DE102015213224A1 - Charging current fuse - Google Patents

Abstract

Vehicle (1) with a high-voltage battery (2) and with a high-voltage vehicle electrical system (3a, 3b), the high-voltage battery being chargeable on a vehicle-external charging device (10), the vehicle comprising a first control unit (6), the vehicle a first adjustable Fuse (S1), and a first triggering threshold of the first adjustable fuse is adjustable by the first control unit.

Description

The invention relates to a vehicle with a high-voltage battery and a high-voltage vehicle electrical system, wherein the high-voltage battery is loadable wired to a vehicle-external charging device, a charging device for wired charging a high-voltage battery of a vehicle, comprising an AC-DC converter for converting AC power from an AC voltage network into DC and a system comprising a vehicle having a high voltage battery and a high voltage vehicle electrical system, said high voltage battery being cabled to an offboard charging device, and comprising a charging device for cabling the high voltage battery of the vehicle, comprising an AC to DC converter for converting AC power from an AC mains to DC.

Various vehicles with an electrified powertrain can be charged at vehicle-external charging stations. According to the prior art, a DC charging station is connected via a connection to the AC network. The DC charging station includes an AC-to-DC converter (AC-to-DC converter) for converting the AC power from the grid into DC having a predetermined voltage and current value for charging a high-voltage battery of the vehicle.

For charging, the vehicle is connected by cable to the vehicle-external charging station in electrical connection. The charging station and the vehicle have a common charging interface. The charging interface includes DC lines, a ground line and lines for control signals. Typically, the charging interface is designed as a male-female connection. Most of the charging plug is a charging callout of the charging station and the charging socket associated with the vehicle. For charging, that is, for receiving the DC power supplied by the charging station, the vehicle has a DC charging architecture, which is part of the high-voltage vehicle electrical system.

When connected to a vehicle charging station, i. When manufactured charging connection, a charging circuit forms from the vehicle's external AC power to the vehicle-integrated high-voltage battery. In the circuit there is an additional switching unit with contactors, through which the DC connection between the vehicle and the charging station despite manufactured charging connection by wiring the contactors is separable and manufacturable. The contactors are usually connected by a charging management.

For error cases, i. especially for any short circuits in the charging circuit of the charging circuit is electrically secure. During normal operation, the current flow in the charging circuit from the charging station to the high-voltage battery. In particular, in the event of a fault, the high-voltage battery, which can act both as a power source and as a current sink, in such a fault, also act as a power-feeding, i. Electricity then flows in the direction of the charging station.

To protect even such a fault, the charging station has a first fuse (eg a fuse or a thermomagnetic circuit breaker) and the charging architecture on a second fuse (eg a fuse or a thermomagnetic circuit breaker), wherein the line strands located between the two fuses are designed so that both the tripping current of the first fuse and the tripping current of the second fuse are capable of carrying.

It is an object of the invention to provide an improved vehicle having a high voltage battery and a high voltage vehicle electrical system, wherein the high voltage battery is chargeable on an offboard charging device, an improved charging device for wired charging a high voltage battery of a vehicle, comprising an AC to DC converter for converting Alternating current from an AC voltage network to DC, and an improved system comprising a vehicle with a high-voltage battery and a high-voltage vehicle electrical system, wherein the high-voltage battery is wired to a vehicle-external charging device, and comprising a charging device for wired charging the high-voltage battery of the vehicle, comprising an AC DC converter for converting alternating current from an alternating voltage network into direct current, form.

This object is achieved by an improved vehicle according to claim 1, an improved loading device according to claim 2 and an improved system according to claim 3. Advantageous embodiments and further developments of the invention will become apparent from the dependent claims.

According to the invention, the vehicle comprises a first control unit and a first adjustable fuse, wherein a first triggering threshold of the first adjustable fuse is adjustable by the first control unit.

This means that the high-voltage vehicle electrical system is protected by an adjustable fuse. The triggering threshold is adjustable by the vehicle's control unit. The advantage of this is that an electrical fuse of the high-voltage electrical system is not immutable - based on the current carrying capacity of the high-voltage vehicle electrical system - takes place, but in particular trigger thresholds are adjustable, which are below the current carrying capacity of the high-voltage vehicle electrical system.

According to a preferred variant of the invention, the first adjustable fuse is an electronic fuse. Alternatively, the adjustable fuse is a relay that is controllable by the first control unit, wherein the triggering threshold is designed as an adjustable control parameter of a software function of the first control unit for monitoring the fuse. The relay must be designed with a suitable separation capability for the maximum short-circuit current.

Furthermore, the first control unit is set up for the transmission of communication signals with the charging device. This means that data information can be transmitted between the first control unit and the charging device.

According to the invention, the charging device comprises a second control unit and a second adjustable fuse, wherein a second triggering threshold of the second adjustable fuse is adjustable by the second control unit.

This means that the loader is secured by an adjustable fuse. The trip level is adjustable by the charger's own control unit. The advantage of this is that an electrical fuse of the charging device is not invariably - based on the current carrying capacity of the components of the charging device - takes place, but in particular trigger thresholds are adjustable, which are below the current carrying capacity of the components of the charging device.

According to a preferred variant of the invention, the second adjustable fuse is an electronic fuse. Alternatively, the adjustable fuse is a relay that is controllable by the second control unit, wherein the triggering threshold is designed as an adjustable control parameter of a software function of the second control unit for monitoring the fuse.

Furthermore, the second control unit is set up for the transmission of communication signals with the vehicle. This means that data information can be transmitted between the second control unit and the vehicle.

According to the invention, the system is designed such that the vehicle comprises a first control unit, the vehicle comprises a first adjustable fuse, a first triggering threshold of the first adjustable fuse is adjustable by the first control unit, the charging device comprises a second control unit, the charging device comprises a second adjustable fuse and a second triggering threshold of the second adjustable fuse is adjustable by the second control unit.

This means that the system is backed up by two adjustable fuses. The respective triggering thresholds can be set by the respective control units. The advantage of this is that the electrical fuse of the high-voltage electrical system is not immutable - based on the current carrying capacity of the high-voltage vehicle system - takes place, but in particular trip thresholds are adjustable, which are below the current carrying capacity of the high-voltage vehicle electrical system and the electrical fuse of the charging device is not invariable - the current carrying capacity of the components Loading device oriented - takes place, but in particular trigger thresholds are adjustable, which are below the current carrying capacity of the components of the charging device.

This is particularly advantageous when a vehicle is loaded on a charging device, wherein the high-voltage vehicle electrical system and the charging device are designed differently with respect to their respective current carrying capabilities. Then, the fuse that protects the respective system part (vehicle high voltage vehicle or charging device) with the design for higher currents, can be adapted to the current carrying capacity of the system part with the design for low currents. Thus, both system parts, i. not only the system part, whose fuse is designed for lower currents, hedged to the low currents. This makes it possible to ensure safe electrical charging vehicles of different design of the high-voltage vehicle electrical system to charging devices of different electrical design of the components of the charging device.

According to a further embodiment of the invention is for wired charging of the high-voltage battery of the vehicle to the vehicle external charging device, a wired charging connection between the vehicle and the charging device via a charging interface electrically and mechanically produced, the charging interface a vehicle associated with the socket and one of the charging device via a charging cable associated with a connector.

Charging is with a charging cable, via which the vehicle is connectable to the charging device. For this purpose, a charging plug attached to the charging cable is inserted in a socket of the vehicle as a counterpart, thus producing a charging connection.

Furthermore, it is advantageous if communication signals can be transmitted bidirectionally via the charging interface between the first control unit and the second control unit, a first communication signal comprises a first value for current carrying capacity of the vehicle's onboard network, and a second communication signal comprises a second value for current carrying capacity of the charging device.

The two control units can thus mutually exchange information about the design for carrying current of the other system part, i. the control unit of the charging device can transmit the current carrying capacity of the charging device to the control unit of the vehicle and vice versa. As a result, when the charging connection is established in both control units, the values are stored via the current carrying capacity of the own system part and the values of the other system part. The value on the current carrying capacity of the own system part is already stored in the relevant control unit.

It is particularly advantageous if the smaller value of the first and second values can be set as the first triggering threshold and the smaller value of the first and second values can be set as the second triggering threshold.

Consequently, when loading both system parts are secured to the smaller current carrying capacity in the system. Thus, in an error situation that can occur anywhere in the system, the system is optimal, i. hedged to the weakest link in terms of current carrying capacity. In this way, vehicles of any design of the high-voltage vehicle electrical system can be charged to any charging device. Vehicles and charging device are thus maximally interoperable, since both the vehicle and the charging device with respect to their protection of current carrying capacity are upwards and downwards compatible.

According to a further variant of the invention, the first and the second adjustable fuse are designed as electronic fuses. Alternatively, the adjustable fuses are each designed as a relay which can be controlled by the respective control unit, the triggering threshold being designed as an adjustable control parameter of a software function of the control unit for monitoring the fuse.

The invention is based on the following considerations:
Electric vehicles are charged in particular for rapid charging with DC voltage. In this case, an AC-DC converter is connected in a vehicle-external charging station directly to the memory in the vehicle, which receives DC, via a male-female connection. The advantage of this DC charging method is that the energy conversion (conversion of the AC mains current into the direct current for the vehicle battery) takes place in the vehicle-external charging station and the necessary power electronics can thus be accommodated in the charging station. The charging current can be "looped" directly to the high-voltage battery via a charging cable external to the vehicle, the plug-socket connection and a high-voltage vehicle electrical system in the vehicle. Thus, very high charging power can be realized in-vehicle without weight penalty for the vehicle.

A scaling of the charging power is possible regardless of the vehicle type. Depending on the network performance and the existing power of the charging station, a lower or very high charging power can be realized. The vehicles to be charged also use different charging currents. Thus, e.g. small storage of PHEV vehicles less receptive than very large storage in pure electric vehicles. The maximum charging current is correspondingly different. This depends on the respective vehicle type.

In practice, therefore, different charging stations with differently designed vehicles come together with regard to the charging power. The difference is primarily due to the respective charge current strength. Especially with the vehicle external charging technology, there are very different charging power. This starts with a few kW (charging with domestic infrastructure) up to a few hundred kW (on the way to fast charging station). The performance differences in charging stations thus move in several orders of magnitude.

Since DC charging is a "backward-current" charging process, the design of the charging station and the high-voltage vehicle electrical system must also take into account the case where e.g. a very high current flows through the charging line through a short circuit in the charging station from the memory of the vehicle.

Because of these different performance considerations of vehicles and charging stations, either all charging stations and vehicles must also be designed for the maximum current rating (which is likely to increase even further in the future), or additional protective elements would have to be installed in the charging plug and charging socket. Apart from cost disadvantages, this is an adverse solution due to space restrictions. Rather, the goal is to choose the application-specific optimal, ie the necessary and sufficient for the application, interpretation. For example, the high-voltage cables in the vehicle and to the charging station belonging charging lines should be as low as possible cross-section (and thus light) and not generally maximum cross-section high (and thus heavy) for the few charging situations when the vehicle in question is loaded at a maximum efficient charging station. Even such an approach in the sense of maximum design is problematic if at later times even more powerful charging stations supplement the charging infrastructure. Then even the original maximum design of the high-voltage vehicle electrical system would no longer be sufficient.

It is therefore proposed to apply an improved, advantageous protection and design concept. This allows a vehicle with low charging power and small cable cross-sections to be operated at a very powerful charging station without generating an electrical overload on components in the vehicle in the event of a fault.

The central element is an adaptively adjustable protective device in the charging station, which is automatically set to the parameters of the vehicle and an adaptive adjustable protection device in the vehicle, which is automatically adjusted to the performance of the charging station. It is an adjustable protection device, which makes it possible to interconnect a regenerative vehicle with a charging device while the protection device with regard to the current carrying capacity on the weakest link (in the vehicle or the charging station) set.

This means that a vehicle with any charging power can be interconnected with any charging station without restriction. In particular, since the charging power in the field of vehicle electromobility develop dynamically, are applications in which a particular vehicle from charging to charging depending on the respective charging station in a charging more powerful or less powerful than the respective charging station in another charging.

The same applies to a particular charging station, which is more powerful from charging to charging depending on the particular vehicle to be charged in one charging process or less powerful than the respective vehicle in another charging.

The protective device may be either in the vehicle, in the charging device, or preferably both in the vehicle and in the charging station. There is communication between the vehicle and the charging device to exchange information about the respective current carrying capabilities. The fuse or both fuses are set to the value of lowest current carrying capacity. The setting is made via adjustable electronic fuses or through a monitoring circuit with current measurement and operation of switches. The setting values can be individual current values as well as I-T characteristics.

The power transmission path, the set size information source, and the adjustment mechanism are designed so that information corruption is always made to the smallest safest value.

In particular, the method is not limited to DC charging, but to any regenerative, i.e.. bidirectional charging method applicable, e.g. in the case of an on-board AC-DC charger, in which AC charging current is transferred to the vehicle for charging.

An advantage of the invention is that the design of all present in the energy transmission path elements can be aligned to the respective system requirements, since the respective more powerful counterpart (i.e., vehicle or charging station) can be hedged to the power limit of the respective lower-power counterpart. This avoids over-interpretation and thus weight, installation space and costs for vehicles and charging infrastructure through thinner and lighter cable strands. In particular, a dynamic development of the charging infrastructure to higher powers does not limit the compatibility of weaker-wiring vehicles. In addition, there is no restriction on the charging power, which would have to be specified by the design of the charging system for faults (for example short-circuits).

Hereinafter, a preferred embodiment of the invention will be described with reference to the accompanying drawings. This results in further details, preferred embodiments and further developments of the invention. The same reference numerals stand for the same technical features. In detail, show schematically

1 System of a vehicle and a loader ...

2 System consisting of a vehicle and a loading device with a fault in the vehicle subsystem

3 System of a vehicle and a charging device with fault in the subsystem charging device

The 1 - 3 show schematically a vehicle ( 1 ) with a high-voltage battery ( 2 ) and a high-voltage on-board electrical system ( 3a . 3b ; short HVBN). The HVBN is a DC on-board network with the two polarities (+) and (-). In the HVBN, high-voltage consumers ( 4 ) be integrated. The vehicle has a charging socket ( 8th ). Furthermore, the vehicle has an electronic fuse (S1), which is controlled by a control unit ( 6 ) of the vehicle is adjustable. The fuse (S1) is located inside the battery without restriction of generality ( 2 ). It can also fuse (S1) outside the battery in the area of the high-voltage vehicle electrical system ( 3a . 3b ) be located.

The vehicle can be installed at an external vehicle charging station ( 10 ) getting charged. The charging station is powered by a public AC grid (if 11 ) and has an AC-DC converter ( 13 ) on. The charging station has an electronic fuse (S2), which is supplied by a control unit ( 14 ) of the charging station is adjustable. Furthermore, the charging station has a charging cable, at one end of a charging plug ( 9 ) is located.

In an electronic fuse semiconductor elements take over the task of the separating element. These are characterized by fast response (power off within micro-seconds) and a simple way to adjust the switching threshold. This can e.g. be made by specifying a threshold voltage. In the case of the charging station, it makes sense that the semiconductor elements used are also used for voltage conversion, in order to achieve a shutdown in the event of a short circuit. In this case, the functional safety required for safety measures must be ensured for the shutdown.

The charging plug is compatible with the charging socket of the vehicle and forms with it a charging interface ( 7 ). With the charging interface, electrical power in the form of two-pole DC voltage can be fed into the high-voltage battery via the charging interface. A charging process can be controlled by a charging management of the vehicle, whereby with contactors ( 5 ) the charging lines can be connected.

The HVBN is designed for a maximum charging current with which the high-voltage battery can be charged. This current reflects the current carrying capacity of the vehicle. The charging station including the charging cable, also referred to as charging device, is also designed for a maximum charging current that can be output for charging the battery of the vehicle. This current reflects the current carrying capacity of the charging station.

Basically, the two fuses (S1) and (S2) are set to the current carrying capacities of the subsystems that comprise the fuses, i. E. the fuse (S1) is set to the current carrying capacity of the HVBN and the fuse (S2) is set to the current carrying capacity of the charging station.

Via the charging interface, which also establishes a communication line between the control unit of the vehicle and the control unit of the charging station when the charging connection is established, the values for the respective current carrying capacities of the vehicle subsystem and the charging station subsystem can be exchanged bidirectionally. Ultimately, the current carrying capacity of both subsystems is stored in both control units. Both control units set the trigger level of the electronic fuse to the smaller of the two values, i. Both fuses protect against a current that is higher than the lower current carrying capacity.

The beneficial effect is the 2 and 3 removable. In case of an error according to 2 forms a short circuit on the part of the subsystem of the charging station (represented by lightning symbol), for example in the area of the charging cable. Consequently, no current flows through the fuse of the charging station. Instead, there is a return current from the high-voltage battery over the short-circuit, with which the high-voltage battery discharges itself. If the current carrying capacity of the HVBN is higher than the current carrying capacity of the charging device, the fuse (S1) remains in the system as the only functional fuse, which is set according to the invention to the value of the smaller current-carrying capacity and thus to the current-carrying capacity of the charging device. Otherwise, the fuse would be set to the higher current carrying capacity of the vehicle subsystem in which the fuse itself is located and the "weakest link" in the fault circuit would be the portion of the charging cable between the charging plug and the short circuit. A melting of the charging cable would be a conceivable continuation of the fault. By setting the fuse (S1), however, the error is effectively prevented.

In case of an error according to 3 A short circuit forms on the part of the subsystem of the vehicle (represented by the lightning symbol), for example in the HVBN area. Consequently, no current flows through the fuse of the vehicle. Instead, there is a current flow through the short circuit and the high-voltage battery is no longer charged. If the current-carrying capacity of the charging device is higher than the current carrying capacity of the HVBN, the fuse (S2) remains in the system as the only functional fuse, which is set according to the invention to the value of the smaller current-carrying capacity and thus to the current carrying capacity of the HVBN. Otherwise, the fuse would be set to the higher current carrying capacity of the charging subsystem in which the fuse itself is located and the "weakest link" in the fault circuit would be the HVBN portion between the charging socket and the short circuit. A melting down of parts of the HVBN would be a conceivable continuation of the error case. By setting the fuse (S2), however, the error is effectively prevented.

Due to the adjustability of a fuse in both subsystems, a vehicle can either be charged to a charging station designed for higher charging currents, such as the vehicle, so that the fuse of the charging station is adapted to the lower current rating of the vehicle when charging, or it can Vehicle are loaded at a charging station, which is designed for lower charging currents as the vehicle, so that the fuse of the vehicle is adapted to the lower current rating of the charging station when charging. In other words, a charging station can be used both for the charging of a vehicle that is protected for faults and that is designed for higher or lower charging currents than the charging station. This results in a maximum interoperability of any loadable vehicles ( 1 ) and any charging stations ( 10 ) for loading according to 1 ,

Claims (11)

Vehicle ( 1 ) with a high-voltage battery ( 2 ) and with a high-voltage on-board electrical system ( 3a . 3b ), wherein the high-voltage battery on an external vehicle charging device ( 10 ) is chargeable, characterized in that - the vehicle has a first control unit ( 6 ), - the vehicle comprises a first adjustable fuse (S1), and - a first triggering threshold of the first adjustable fuse is adjustable by the first control unit. Loading device ( 10 ) for wired charging of a high-voltage battery ( 2 ) of a vehicle ( 1 ), comprising an AC-DC converter ( 13 ) for the conversion of alternating current from an alternating voltage network ( 11 ) in direct current, characterized in that - the charging device has a second control unit ( 14 ), - the charging device comprises a second adjustable fuse (S2), and - a second triggering threshold of the second adjustable fuse is adjustable by the second control unit. System comprising a vehicle ( 1 ) with a high-voltage battery ( 2 ) and with a high-voltage on-board electrical system ( 3a . 3b ), wherein the high-voltage battery on an external vehicle charging device ( 10 ) is loadable by cable, and comprising a charging device ( 10 ) for wired charging of the high-voltage battery ( 2 ) of the vehicle ( 1 ), comprising an AC-DC converter ( 13 ) for the conversion of alternating current from an alternating voltage network ( 11 ) in direct current, characterized in that - the vehicle has a first control unit ( 6 ), - the vehicle comprises a first adjustable fuse (S1), - a first triggering threshold of the first adjustable fuse is adjustable by the first control unit, - the charging device has a second control unit ( 14 ), - the charging device comprises a second adjustable fuse (S2), and - a second triggering threshold of the second adjustable fuse is adjustable by the second control unit. System according to claim 3, characterized in that - for wired charging of the high-voltage battery of the vehicle to the vehicle-external charging device, a wired charging connection between the vehicle and the charging device via a charging interface ( 7 ) is electrically and mechanically producible, - wherein the charging interface a vehicle associated with the socket ( 8th ) and one of the charging device via a charging cable associated with a plug ( 9 ). System according to claim 4, characterized in that - via the charging interface communication signals between the first control unit and the second control unit are bidirectional, - a first communication signal comprises a first value for current carrying capacity of the vehicle's onboard network, and - a second communication signal has a second value for Current carrying capacity of the charging device comprises. System according to claim 5, characterized in that - as the first triggering threshold, the smaller value of the first and second values is adjustable, and - is adjustable as the second triggering threshold, the smaller value of the first and second values. Vehicle according to claim 1, characterized in that - the first adjustable fuse is an electronic fuse. Vehicle according to claim 1 or 7, characterized in that - the first control unit is arranged for the transmission of communication signals with the charging device. Loading device according to claim 2, characterized in that - the second adjustable fuse is an electronic fuse. Loading device according to claim 2 or 9, characterized in that - the second control unit is arranged for the transmission of communication signals with the vehicle. System according to one of claims 3 to 6, characterized in that - the first adjustable fuse is designed as an electronic fuse, - and the second adjustable fuse is designed as an electronic fuse.

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