Charger for charging an electrical energy storage device of a vehicle

Abstract

A charger for charging an energy storage device of a vehicle is described, wherein the charger is designed to convert an alternating current provided via a first line and a second line at an input of the charger into a direct current for charging the energy storage device. The charger comprises an isolating switching element at the input, which is designed to interrupt the first line when open. The charger further comprises a blocking element, which is arranged in a bridging path arranged parallel to the isolating switching element for bridging the isolating switching element. The blocking element is designed to block a direct current provided via the first line and the second line and to at least partially allow an alternating current provided via the first line and the second line to pass through.

Description

The invention relates to a charging device for charging an electrical energy store of a (motor) vehicle.A vehicle with an electric drive (in particular an electric vehicle or a plug-in hybrid vehicle) comprises an electrical (in particular an electrochemical) energy store which can be connected to a charging station and charged via a charging interface of the vehicle. There are various conductive, i.e. cable-bound, charging technologies for charging the electrical energy store. In the case of so-called AC charging or AC charging, a charger is located in the vehicle, which converts an AC current (also referred to as AC current) into a DC current (also referred to as DC current) for charging the electrical energy store. An AC (alternating current) or alternating current is transmitted on the charging cable between the charging station, e.g. a wallbox, and the vehicle. In the case of so-called DC charging or DC charging, a DC (direct current) or DC current is transmitted on the charging cable.The charging interface of the vehicle may comprise contact elements used for both DC current and AC current. In particular, the charging interface can have a first contact element which is coupled to the positive pole of the direct current for DC charging and to a first phase of the alternating current for AC charging. Furthermore, the charging interface can have a second contact element which is coupled to the negative pole of the direct current for DC charging and to the neutral conductor of the alternating current for AC charging with a second phase or to the neutral conductor of the alternating current. DE 10 2015 016 651 A1 shows, for example, a charging device for a motor vehicle and a method for charging a battery.The present document is concerned with the technical object of providing an efficient and reliable AC charger for a vehicle, wherein the vehicle has a charging interface with contact elements which are used for both AC charging and DC charging.The object is achieved by the independent claim. Advantageous embodiments are described inter alia in the dependent claims. It is pointed out that additional features of a claim dependent on an independent claim can form a separate invention which is independent of the combination of all features of the independent claim without the features of the independent claim or only in combination with a subset of the features of the independent claim and which can be made the subject matter of an independent claim, a divisional application or a subsequent application. This applies in the same way to technical teachings described in the description, which may form an invention independent of the features of the independent claims.According to one aspect, a charging device for charging an electrical, in particular an electrochemical, energy store of a (motor) vehicle is described. The energy store can have a rated voltage of 100 V or more, in particular of 200 V or more or of 400 V or more. The energy store can be configured to store electrical energy for the operation of an electric drive machine of the vehicle.The charger is designed to convert an alternating current provided at the input of the charger via a first line and via a second line into a direct current for charging the energy store. The alternating current can be provided, for example, with an alternating voltage of 110 V or of 230 V. The charger can thus be configured for a direct and / or alternating voltage between the first line and the second line of 100 V or more, in particular of 200 V or more.The charger comprises at the input an isolating switch element which is configured to interrupt the first line in the open state. The isolation switching element may comprise (in particular be) a relay, in particular a mechanical relay or a semiconductor relay. Alternatively or additionally, the charging device can comprise at the input a second isolating switching element which is designed to interrupt the second line in the open state.Furthermore, the charging device comprises a blocking element which is arranged in a bridging path arranged parallel to the isolating switching element for bridging the isolating switching element. The blocking element is preferably designed for a direct voltage and / or alternating voltage between the first line and the second line of 100 V or more, in particular of 200 V or more.The isolation switching element may be configured to short-circuit the bypass path in the closed state. The bypass path can be provided to reduce the inrush current when the isolation switching element is closed. The bridging path can be designed, in particular, for precharging one or more components of the charger. For this purpose, the charger may have a limiting resistor (as a dedicated and / or independent resistor component) arranged on the bridging path. The limiting resistor may be arranged in series with the blocking element.The blocking element is configured to block (substantially completely) a direct current provided via the first line and via the second line, and to let an alternating current provided via the first line and via the second line pass at least partially.The blocking element can be configured, for example, to block a current, in particular direct current and / or alternating current, provided via the first line and via the second line, with the first polarity, and to let a half-wave of an alternating current provided via the first line and via the second line, with a second polarity, which is opposite to the first polarity, pass (while the half-wave of the alternating current with the first polarity is blocked by the blocking element).The blocking element may comprise a diode (wherein the reverse direction of the diode corresponds to the first polarity and the forward direction of the diode corresponds to the second polarity), for example.On the other hand, the blocking element can be configured to allow an alternating current provided via the first line and via the second line to pass substantially completely (i.e. both half-waves of the alternating current). The blocking element can comprise a capacitor, for example.A charger with a (passive) blocking element (which optionally comprises only one or more passive components) can thus be provided in order to enable the charger in an efficient and reliable manner for AC charging and for DC charging via the same (first and second) lines.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 charger described in this document.The vehicle can comprise an electrical energy store and a charging interface (in particular a charging socket) with a first contact element and with a second contact element. Furthermore, the vehicle can comprise a first line electrically conductively connected to the first contact element and a second line electrically conductively connected to the second contact element, wherein the input of the charger is electrically conductively connected to the first line and to the second line.The vehicle may be configured to use a direct current provided via the first line and the second line directly for charging the energy store. Furthermore, the vehicle can be designed to convert an alternating current provided via the first line and the second line by means of the charger into a direct current for charging the energy store.The vehicle may include a control unit. The control unit can be configured to cause the isolating switching element of the charger to remain in the open state if it is detected, in particular as long as it is detected, that a direct current is provided via the first line and the second line. Furthermore, the control unit can be configured to cause the isolating switch element of the charger to be transferred into the closed state after a predefined precharge time period has elapsed and / or when (e.g. as soon as) the voltage across the isolating switch element is less than a predefined voltage threshold value, such that the bypass path is short-circuited by the isolating switch element if, in particular as soon as, it is detected that an alternating current is provided via the first line and the second line.It should be noted that the devices and systems described herein may be used both alone and in combination with other devices and systems described herein. Furthermore, any aspects of the devices and systems described herein may be combined in a variety of ways. In particular, the features of the claims can be combined with one another in many ways. Furthermore, features listed in brackets are to be understood as optional features.The invention is described in more detail below with reference to exemplary embodiments. Figure shows FIG. 1 is a block diagram of an example charging system; FIG. 2 ashows an exemplary AC and DC charging device for a vehicle; and FIG. 2 b shows an exemplary AC charger for a vehicle.As set forth at the beginning, the present document is concerned with the provision of an efficient and reliable AC charger for a vehicle, which can be used in connection with a charging interface having common contact elements (in particular pins) for AC charging and for DC charging. In this context, FIG. 1 shows a block diagram of an exemplary charging system having a charging station 110 (e.g., a wallbox) and a vehicle 100. The vehicle 100 comprises an electrical energy store (not shown) which can be charged with electrical energy from the charging station 110. The vehicle 100 comprises a charging socket 101 (generally referred to as a charging interface) to which a corresponding (charging) plug 111 of a charging cable 112 can be plugged. The charging socket 101 and the plug 111 typically form a plug-in system. The charging cord 112 may be fixedly connected to the charging station 110 (as shown).On the other hand, the charging cable 112 may be connected to the charging station 110 via a plug connection (e.g., during AC charging).The charging interface 101 of the vehicle 100 typically comprises different contact elements for AC charging and for DC charging. In certain countries (e.g., in the USA, according to the NACS (North American Charging Standard)), charging stations 110 may optionally use the same contact portions for AC charging and for DC charging. As a result, an alternating current or a direct current can be provided at a pair of contact elements of the charging interface 101 depending on the charging station 110. The vehicle 100 may include a charging device configured for such a situation, as exemplarily illustrated in FIG. 2 a.The charging device illustrated in FIG. 2 acomprises a first line 221 and a second line 222, wherein the first line 221 is electrically conductively coupled to a first contact element and the second line 222 is electrically conductively coupled to a second contact element of the charging interface 101 of the vehicle 100. In a first charging situation, a direct current can be provided via the lines 221, 222, which direct current can be conducted directly via the switching elements 261 to the electrical energy store 260 in order to charge the energy store 260.In a second charging situation, an alternating current can be provided via the lines 221, 222, wherein the alternating current is converted by a charger 250 into a direct current which is then conducted (optionally via the switching elements 262) to the energy store 260 in order to charge the energy store 260.FIG. 2 bshows an exemplary AC charger 250 which has on the input side a disconnection switching element 251 which is configured to disconnect (in the open state) the first line 221 when a direct current is provided via the lines 221, 222. On the other hand, if it is detected that an alternating current is provided via the lines 221, 222, the isolating switch element 251 may be closed to couple the subsequent components 271, 272, 273, 274 of the charger 250 to the lines 221, 222, and so to enable the transformation of the alternating current on the lines 221, 222 into a direct current for charging the energy store 260.The charging device 250 illustrated in FIG. 2 b comprises the following components,• an input-side filter unit 271;• a power factor correction (PFC) unit 272;• an LLC unit 273 with galvanic isolation; and / or• a DC filter unit 274.The charger 250 may have one or more components, in particular capacitances, which lead to a relatively high inrush current when the isolating switching element 251 is closed. For this purpose, the charger 250 may have a limiting resistor 252 which bypasses the isolating switching element 251 and which is designed to limit the inrush current when the isolating switching element 251 is closed. In particular, the limiting resistor 252 has the effect that the one or more components of the charging device 250 are at least partially charged via the limiting resistor 252 in a pre-charging phase already before the disconnection switching element 251 is closed, such that an excessively high inrush current no longer flows via the disconnection switching element 251 when the disconnection switching element 251 is closed.The limiting resistor 252 is disposed in a bypass path, the bypass path being disposed in parallel with the cut-off switching element 251.The limiting resistor 252 bypassing the isolation switching element 251 results (without using the blocking element described in this document) in that, when a DC voltage is applied to the lines 221, 222, this DC voltage is passed via the limiting resistor 252 to the one or more subsequent components 271, 272, 273, 274 of the charger 250, which can lead to an impairment of the one or more subsequent components 271, 272, 273, 274 of the charger 250.The charger 250 comprises a blocking element 253 arranged (on the bypass path) in series with the limiting resistor 252 and configured to selectively block a direct current and / or a direct current provided via the lines 221, 222. On the other hand, the blocking element 253 is configured to allow an alternating current and / or an alternating voltage, which is provided via the lines 221, 222, to pass at least partially and optionally completely.In the example illustrated in FIG. 2 b, the blocking element 253 comprises a diode configured to block a direct current and / or a direct current (with a specific polarity) provided via the lines 221, 222. If an alternating current and / or an alternating voltage is provided via the lines 221, 222, a half-wave of the alternating current or the alternating voltage can pass through the diode in each case in order to charge the one or more components of the charging device 250 and in order thereby to reduce the inrush current when the isolating switching element 251 is closed. Thus, it is also possible to effect a pre-charging of the one or more components, in particular capacitances, of the charger 250.In another example, the blocking element 253 comprises a capacitor configured to selectively block a direct current and / or a direct current while an alternating current and / or an alternating current passes the capacitor (substantially completely).An AC charger 250 is thus described, which can be connected in an efficient and reliable manner to lines 221, 222, which can have a direct current or a direct voltage or an alternating current or an alternating voltage depending on the charging situation. The charger 250 has a (passive) blocking element 253 which is arranged in parallel with the isolating switching element 251 of the charger 250 and which is designed to protect the subsequent components 271, 272, 273, 274 of the charger 250 from a high-voltage DC voltage.

Claims

Charging device (250) for charging an energy store (260) of a vehicle (100); wherein - the charging device (250) is designed to convert an alternating current provided via a first line (221) and via a second line (222) at an input of the charging device (250) into a direct current for charging the energy store (260); - the charging device (250) comprises at the input a disconnection switching element (251) which is designed to disconnect the first line (221) in an open state; and - the charging device (250) comprises a blocking element (253) which is arranged in a bridging path arranged parallel to the disconnection switching element (251) for bridging the disconnection switching element (251); wherein the blocking element (253) is configured to: - block a direct current provided via the first line (221) and via the second line (222); and - let an alternating current provided via the first line (221) and via the second line (222) pass at least partially.The charger (250) according to claim 1, wherein the blocking element (253) is configured to - block a current, in particular direct current and / or alternating current, provided via the first line (221) and via the second line (222), with a first polarity; and - let a half-wave of an alternating current provided via the first line (221) and via the second line (222), with a second polarity, which is opposite to the first polarity, pass.The charger (250) of any preceding claim, wherein the blocking element (253) comprises a diode.The charger (250) according to any one of the preceding claims, wherein the blocking element (253) is configured to substantially completely allow an alternating current provided via the first line (221) and via the second line (222) to pass.The charger (250) of any preceding claim, wherein the blocking element (253) comprises a capacitor.The charger (250) of any preceding claim, wherein - the charger (250) comprises a limiting resistor (252) disposed on the bypass path; and - the limiting resistor (252) is disposed in series with the blocking element (253).The charger (250) according to any one of the preceding claims, wherein the charger (250), in particular the blocking element (253), is configured for a direct and / or alternating voltage between the first line (221) and the second line (222) of 100V or more, in particular of 200V or more.Charger (250) according to one of the preceding claims, wherein the isolating switching element (251) comprises a relay, in particular a mechanical relay or a semiconductor relay.Vehicle (100) comprising - an electrical energy store (260); - a charging interface (101) having a first contact element and having a second contact element; - a first line (221) electrically conductively connected to the first contact element and a second line (222) electrically conductively connected to the second contact element; and - a charger (250) according to one of the preceding claims; wherein an input of the charger (250) is electrically conductively connected to the first line (221) and to the second line (221); wherein the vehicle (100) is configured to - use a direct current provided via the first line (221) and the second line (222) directly for charging the energy store (260); and - converting an alternating current provided via the first line (221) and the second line (222) by means of the charger (250) into a direct current for charging the energy store (260).Vehicle (100) according to claim 9, wherein the vehicle (100) comprises a control unit which is configured to - cause the isolating switch element (251) of the charger (250) to remain in the open state if, in particular as long as, it is detected that a direct current is provided via the first line (221) and the second line (222); and - cause the isolating switch element (251) of the charger (250) to be transferred to the closed state after a predefined pre-charge period has elapsed and / or if a voltage across the isolating switch element (251) is less than a predefined voltage threshold value, such that the bridging path is short-circuited by the isolating switch element (251) if, in particular as soon as, it is detected that an alternating current is provided via the first line (221) and the second line (222).

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