DE102021201468B3 - Architecture and circuit topology to ensure switchable all-pole galvanic isolation in high-voltage battery systems - Google Patents

Abstract

The invention relates to a high-voltage battery system (1000) with at least one high-voltage battery unit (100), which has a high-voltage battery (200) which has two battery poles (210, 220), between which a high voltage drops when the high-voltage battery (200) is charged, and a protective circuit (300) for all-pole galvanic isolation of the two battery poles (210, 220) from the connection poles (410, 420) of at least one connection (400) of the high-voltage battery unit (100) in a protective state, the protective circuit comprising at least one first switching element (310) and comprises at least one second switching element (320), and a high-voltage, high-power network (800) via which at least one high-voltage consumer (860) is electrically connected, the at least one first switching element (310) as a semiconductor switch (313) and the at least one second switching element (320) is designed as a contactor (324), the at least one being Ha The first switching element (310) designed as a conductor switch (313) is arranged between the one battery pole (210) and the one connection pole (410) of the at least one connection (400) and that at least one second switching element (320) designed as a contactor (324) is arranged between the other battery pole (220) and the other connection pole (420) of the at least one connection (400) and additionally between the one battery pole (210) and the at least one first switching element (310) designed as a semiconductor switch (313) a pyrotechnic fuse (315 ) is arranged, wherein the protective circuit (300) has at least one further first switching element (330) and at least one further second switching element (340) for all-pole disconnection of charge connection poles (510, 520) of a DC voltage charge connection (500) from the battery poles (210, 220) in a disconnected state.The invention further relates to a high voltage battery pack (100) as described above with a high voltage battery (200) and a protection circuit (300).

Description

The invention relates generally to high voltage battery systems. In particular, the invention relates to a high-voltage battery unit and a high-voltage battery system with such a high-voltage battery unit, each of which includes a high-voltage battery, in particular a high-voltage battery unit and a high-voltage battery system for a vehicle with a purely electric drive or a hybrid drive, one of whose drive machines is an electric motor.

It is known from the prior art to equip vehicles with an electric drive. The energy required to drive an electric machine or other high-voltage consumers is stored in a high-voltage battery, both in purely electrically driven vehicles and in hybrid vehicles. Direct voltage is regarded as high voltage if the potential difference is greater than 60 V. As a rule, the voltages of high-voltage batteries, such as those used in motor vehicles, are significantly higher and are in the range between 300 V and 1,000 V, preferably in the range between 400 V and 800 V In the event of an accident in which the insulation of one or more electrical lines can be damaged at the same time, it may be necessary to galvanically isolate the battery poles from the high-voltage grid and its sub-grids. Even in the event of a defect in a high-voltage consumer, it may be necessary with the high-voltage network topologies customary today to galvanically isolate the battery poles from the high-voltage network. A protective circuit is generally provided for this purpose, which can be combined with the high-voltage battery in a high-voltage battery unit. The protective circuit ensures that, in a protective state, the battery poles are galvanically isolated from all high-voltage electrical connections leading out of the high-voltage battery unit.

The bringing about of the galvanic isolation is thus often carried out while large currents are drawn from the high-voltage battery. In the prior art, contactors are used as switching elements, which on the one hand can switch large currents and on the other hand bring about galvanic isolation. In the event of a fault, a short circuit can occur in the high-voltage battery system, among other things, and in this case currents can rise to over 10 kA in a very short time. Due to the large currents, when the contactors are switched it can happen that their isolating contacts are welded together. It is therefore customary in the prior art to provide a further component in series with the contactor, which nevertheless brings about galvanic isolation in the event of damage to the contactor. For this purpose, for example, safety fuses are used, in which a conductor section melts due to the high current flow, or else pyrotechnic fuses, which reliably cut through a conductor when activated by igniting a pyrotechnic propellant charge. Accordingly, a fault involving a short circuit in embodiments according to the prior art becomes an expensive case of damage, which makes it necessary to replace the high-voltage battery and/or the contactors, since damage to the contactors after a short circuit cannot be ruled out even if the separation is functionally error-free .

the DE 10 2015 010 536 A1 describes a battery arrangement for a high-voltage vehicle electrical system in a motor vehicle with a first and a second high-voltage battery, each with a mechanical switching element electrically coupled between a first pole of the respective high-voltage battery and a high-voltage intermediate circuit of the high-voltage vehicle electrical system, one between each second pole of the respective high-voltage battery and the high-voltage intermediate circuit electrically coupled electronic switching element, and a battery control unit, which is designed to close the switching contact of the first mechanical switching element and the first electronic switching element in an electrically conductive state for current-limited pre-charging of the high-voltage To control the intermediate circuit, and to determine a voltage difference between a measured intermediate circuit voltage of the high-voltage intermediate circuit and a measured no-load voltage of the second high-voltage battery and as a function of the determined voltage difference enz to close the switching contact of the second mechanical switching element and / or to control the second electronic switching element in the electrically conductive state. Furthermore, a method for operating such a battery arrangement is described.

From the DE 10 2019 008 835 A1 a vehicle with an electrical high-voltage vehicle electrical system is known, which is divided into two sections, the first section being arranged in a first installation space of the vehicle and the second section being arranged in at least a second installation space of the vehicle. The pairs of potential lines that connect the two sub-networks are connected to a switching unit that can de-energize both potential lines. The switching units are each available as a contactor or semi-conductor terswitch formed or a combination of a contactor and a semiconductor switch.

However, galvanic isolation is not achieved, at least in the case of the switching units that are in the form of conventional semiconductor switches, for example MOSFETs. These only block in one current direction.

The object of the invention is to implement improved galvanic isolation in a protective state and in particular to ensure that the protective state is brought about without causing damage to the high-voltage battery unit or the high-voltage network and its components.

The invention is achieved according to the invention by a high-voltage battery unit having the features of patent claim 1 and a high-voltage battery system having the features of patent claim 6 . Advantageous configurations result from the dependent claims.

The invention is based on the idea of ensuring the battery poles of a high-voltage battery of a high-voltage battery unit with a protective circuit for all-pole galvanic isolation of the two battery poles of the high-voltage battery from the connection poles of at least one connection of the high-voltage battery unit and the charge connection poles of a DC voltage charge connection in a protective state by using a first switching element as semiconductor switch is formed, which separates one battery pole from one connection pole, and to separate the other battery pole from the other connection pole via a second switching element designed as a contactor and to form a further first switching element (330) as a further semiconductor switch that separates the one battery pole from separates the one charge connection pole, and separates the other battery pole from the other charge connection pole via a further second switching element designed as a further contactor (344). l to separate. Since the at least one first switching element designed as a semiconductor switch cannot ensure electrical isolation and only has a blocking direction, which preferably blocks a discharging direction, a pyrotechnic fuse is additionally installed between one battery pole and the first switching element designed as a semiconductor switch to interrupt the electrical line between the one Arranged battery pole and designed as a semiconductor switch first switching element. If a fault is detected and the high-voltage supply is switched off, the first switching element, which is designed as a semiconductor switch, is able to switch so quickly that the currents that occur, which build up, for example, in the event of a short circuit, do not reach a magnitude that, for example, in cause permanent damage to a contactor when de-energized. While DC voltage contactors, which disconnect with a delay time of around 50 ms, can produce currents of up to 15 kA or more when a circuit is interrupted, the increase in current that occurs in the event of a fault can be drastically limited to 200 A to 300 A, for example, when using a semiconductor switch will. This is achieved by the faster switch-off times of less than 1 ms in some cases, for example within 600 ns. Since a semiconductor switch does not block bidirectionally and in the event of damage can be damaged to such an extent that, in the worst case, a conductive, albeit possibly high-impedance, electrically conductive connection forms in the semiconductor switching element, it is important to establish safe galvanic isolation, especially in the event of damage to the semiconductor switch itself, necessary to provide a pyrotechnical fuse in series with the semiconductor switch between the one battery pole and the semiconductor switch, which cuts through a piece of line by igniting a propellant charge. The advantage of the solution is also that the currents required to operate a semiconductor switch are reduced compared to a contactor. Furthermore, the installation space, which is usually limited in a high-voltage battery unit in a vehicle, is reduced.

A high-voltage battery includes battery cells that are connected to one another in series and/or in parallel, so that a high voltage is present between two battery poles of the high-voltage battery when the battery cells are in a charged state. The battery cells can be combined in groups to battery modules, which can have a common temperature and/or load management for the combined battery cells. Several such battery modules can be connected in series or in parallel to form the high-voltage battery.

In particular, a high-voltage battery unit is thus created with a high-voltage battery, which has two battery poles between which a high voltage drops when the high-voltage battery is charged, and a protective circuit for all-pole galvanic isolation of the two battery poles from the connection poles of at least one connection of the high-voltage battery unit in a protective state, wherein the Protection circuit comprises at least one first switching element and at least one second switching element, the at least one first switching element being a semiconductor switch and the at least one second switching element being a contactor, the at least one being a semiconductor ter switch is arranged between the one battery pole and the one connection pole of the at least one connection and that the second switching element designed as a contactor is arranged between the other battery pole and the other connection pole of the at least one connection and additionally between the one battery pole and the one designed as a semiconductor switch first switching element, a pyrotechnic fuse for interrupting the electrical line between the one battery pole and the first switching element designed as a semiconductor switch is arranged in the protected state.

A high-voltage battery unit does not have to be combined in one structural unit. The term high-voltage battery unit is merely the general term for the high-voltage battery and those components that ensure the galvanic isolation of the high-voltage battery poles of the high-voltage battery if necessary.

Furthermore, a high-voltage battery system with
at least one high voltage battery unit, which
a high-voltage battery, which has two battery poles between which a high voltage drops when the high-voltage battery is charged, and a protective circuit for all-pole galvanic isolation of the two battery poles
the terminal poles of at least one terminal of the high-voltage battery unit in a protective state, the protective circuit comprising at least one first switching element and at least one second switching element, and
a high-voltage, high-performance network via which at least one high-voltage consumer, in particular a pulse-controlled inverter (PWR) for generating voltages for at least one electrical machine, is electrically connected, the high-voltage, high-performance network having at least one first connection contact and at least one second connection contact,
wherein the high-voltage, high-power network is connected to the connection in such a way that the at least one first connection contact is electrically connected to the one connection pole and the at least one second connection contact is electrically connected to the other connection pole,
whereby
the at least one first switching element is designed as a semiconductor switch and the at least one second switching element is designed as a contactor, with the at least one switching element designed as a semiconductor switch being arranged between one battery pole and one connection pole of the at least one connection, and the second switching element designed as a contactor between the other Battery pole and the other terminal pole of the at least one terminal is arranged and a pyrotechnical fuse is additionally arranged between the one battery terminal and the switching element designed as a semiconductor switch.

In the meaning used here, the high-voltage battery system also includes the high-voltage battery in addition to a high-voltage grid. A high voltage grid is used as a limited term that does not include the high voltage battery.

In the proposed solution, the short switching time required by the first switching element, which is designed as a semiconductor switch, in order to interrupt the electrical connection, means that the increase in current is also clearly limited in the second switching element. Reliable galvanic isolation can thus also be ensured in each case in the second switching element designed as a contactor. This also makes it possible, in other states in which the high-voltage battery unit is switched off under load, to prevent high loads from acting on the second switching element designed as a contactor. The semiconductor switch can switch high currents as often as you like without causing any damage. At the same time, the load on the second switching element designed as a contactor can be significantly reduced and its service life increased. Overall, the design of the system can be improved so that it can be designed for lower currents that occur, since maximum currents well above 1,000 A are avoided even in damaged states. Furthermore, no irreversibly separating fuse is required and designed in series with the second switching element designed as a contactor. Since the semiconductor switch can also be switched at high frequencies during operation of the battery system, i.e. under load, so-called dynamic damage to the high-voltage battery or its battery cells can be prevented if the semiconductor switch is switched at high frequencies during operation. Current peaks due to low-frequency switching processes, such as those that occur in PTC heating registers, can be prevented or reduced. As a result, the high-voltage battery and its components, in particular its battery cells, can be spared and protected. Such novel applications of the protection circuit are thus made possible.

In order to prevent damage to the insulation that occurs, for example, in the event of an accident and requires the protection state to be triggered, also at other points in the high-voltage network that are at the mind At least one terminal of the high-voltage battery unit are connected to avoid high currents in any case, it is particularly advantageous if the at least one switching element designed as a semiconductor switch is connected to the positive pole of the high-voltage semiconductor battery. In a preferred embodiment of the invention it is therefore provided that one battery pole is a positive pole of the high-voltage battery and the other battery pole is a negative pole of the high-voltage battery. One battery pole, which is the positive pole, is therefore preferably the pole of the high-voltage battery connected to the semiconductor switch.

Provision is particularly preferably made for the at least one connection to be a rated power connection for drawing electrical energy from the high-voltage battery at rated discharge power and/or feeding electrical energy into the high-voltage battery at rated charging power in the high-voltage battery.

The at least one connection of the high-voltage battery unit is therefore preferably designed to take electrical energy from the high-voltage battery or feed it into it at the maximum possible power without causing damage or impairment beyond normal normal wear and tear. A high-voltage, high-performance network is preferably designed accordingly and is designed for energy withdrawal and/or feeding in at such a maximum possible withdrawal power or feed-in power of the high-voltage battery.

In vehicles, however, it is desirable, separately from the components installed in the vehicle, some of which also allow electrical energy to be fed back into the high-voltage battery unit, for example by means of an installed AC direct current charger, which can be connected to a normal household or customary alternating current voltage source To allow charging of the high-voltage battery using high-voltage direct current. Therefore, in addition to the at least one connection, a high-voltage battery unit according to the invention has at least one DC voltage charge connection with a charge connection pole and another charge connection pole, the protective circuit having at least one further first switching element and at least one further second switching element for all-pole disconnection of the charge connection poles of the DC voltage charge connection from the battery poles in a separate state in which the at least one further first switching element is designed as a further semiconductor switch and is arranged between the pyrotechnical fuse and one charge connection pole of the at least one DC voltage charging connection and the at least one further second switching element is designed as a further contactor which is connected between the other battery pole and the other charge connection pole of the at least one DC voltage charge connection is arranged, wherein between d no other switching element and no irreversible fuse is connected in series between the pyrotechnic fuse and the one charge connection pole of the at least one DC voltage charging connection with the further switching element, and no other switching element and no irreversible fuse is connected in series between the other battery pole and the other charge connection pole of the at least one DC voltage charging connection with the further second switching element fuse is connected in series.

One advantage of this solution is that no additional safety elements need to be present in the high-voltage battery unit for the direct-voltage charging connection, via which the high-voltage battery can be charged with high-voltage direct current. Here, too, complete all-pole disconnection can be achieved in that one battery pole is electrically connected via the pyrotechnic fuse, which is arranged between one battery pole and the other first switching element designed as an additional semiconductor switch, and the other battery pole via the additional contactor designed as an additional contactor second switching element is galvanically isolated in the protection state. Further switching elements or irreversible fuses are connected in series neither with the further first switching element nor with further second switching element. Due to the fact that the first switching element and the further first switching element as well as the second switching element and the further second switching element are not connected in series but "in parallel", high-voltage networks that are connected to the high-voltage battery unit can be switched off during the charging process via the DC voltage charging connection . Currents for operating these switching elements can be saved. In addition, and probably more important in practice, the first switching element and the second switching element are not loaded by the charging current, even if the first switching element and the second switching element are in a closed switching state, for example during a charging process with DC voltage via a DC voltage/ Direct voltage converter (DC / DC converter) to support a low-voltage network, such as a 12V network. Although the first switching element and the further first switching elements are each designed as semiconductor switches, so there are no two semiconductor switches in series. This is advantageous since semiconductor switches have slightly higher internal resistances than contactors.

The DC voltage charging station is preferably designed in such a way that it precharges capacities that are present outside the high-voltage battery unit before the charging process to the corresponding high voltage begins.

Likewise, the high-voltage high-performance network, which is connected to the at least one connection of the high-voltage battery unit, is preferably also designed in such a way that it ensures pre-charging via another energy store, for example via a DC/DC converter and a low-voltage battery of an on-board network.

Alternatively, pre-charging can be carried out in a similar way to the prior art, in which this is done via a pre-charging contactor with a series-connected load resistor, which is configured parallel to the first switching element, via a pre-charging switch configured as a semiconductor switch with a series-connected load resistor for current limitation be carried out during the pre-charging, the pre-charging switch designed as a semiconductor switch being connected in parallel to the first switching element with the load resistor arranged in series.

The first switching elements and second switching elements in the high-voltage battery unit are preferably designed such that they only switch to the closed/conductive state when a high voltage is already present between the associated connection poles of the corresponding connection due to precharging. This avoids current peaks when switching to the conductive state.

As a further alternative, the pre-charging can also be carried out by repeatedly switching over the first switching element between the conducting and the blocking state at high frequency, thereby limiting the maximum current increase during the pre-charging.

In vehicles, it is often desirable to provide a second separate high-voltage network in addition to the high-voltage high-power network in which, for example, a drive machine is arranged, which only requires a lower power draw. Therefore, in a preferred embodiment, it is provided that in addition to the at least one connection configured as a nominal power connection, at least one low-power connection is configured in the high-voltage battery unit, the at least one low-power connection for drawing electrical energy from the high-voltage battery below a nominal drawing power and/or feeding in electrical energy is formed into the high-voltage battery with an electrical power below the nominal feed power, wherein a disconnecting element assigned to the at least one low-power connection is formed in the protective circuit in order to interrupt an electrical connection between the high-voltage battery of the at least one high-voltage battery unit and a low-power connection pole of the at least one low-power connection in a fault state , wherein the separating element is designed as a semiconductor switch Netztre nnswitch is and electrically arranged in series with the first switching element designed as a semiconductor switch and electrically between this first switching element and a low-power connection pole of the at least one low-power connection. In a high-voltage battery system, provision is accordingly made for at least one low-power connection to be designed for the additional connection of at least one high-voltage low-power network, the at least one high-voltage low-power network being designed to supply at least one additional high-voltage consumer with electrical energy, the at least one high-voltage low-power network having a lower Rated power for energy withdrawal and/or feed-in as the high-voltage high-power grid, with the at least one low-power connection being assigned a grid disconnecting element in order to interrupt an electrical connection between the high-voltage battery of the at least one high-voltage battery unit and a low-power connection pole in a fault state and to separate the high-voltage low-power grid to be able to, wherein the power isolating element designed as a semiconductor switch power isolating switch is older.

In one variant of the high-voltage battery system, it is provided that the at least one low-power connection is formed in the high-voltage battery unit and the isolating switch is formed in the protective circuit of the high-voltage battery unit and is electrically in series with the first switching element formed as a semiconductor switch and electrically between this first switching element and the at least one low-power connection is arranged. This creates a circuit arrangement in which the various high-voltage networks are all switched off directly in the high-voltage battery unit can become. If the pyrotechnic fuse is connected to the positive pole of the high-voltage battery, the high-voltage low-power network can already be switched off at the at least one low-power connection using the associated isolating switch.

In another variant, it is provided that the at least one low-power connection is formed in or on the high-voltage, high-power grid and the grid circuit breaker is arranged between the high-voltage, high-power grid and the high-voltage, low-power grid in order to form an electrical line between the high-voltage, high-power grid and the high-voltage, low-power grid to be able to disconnect in the fault state. The at least one high-voltage low-power network can thus also be connected at points other than the high-voltage battery unit.

Other variants have a number of low-power connections, which are formed in the high-voltage battery unit and can each be switched off via a mains circuit breaker designed as a semiconductor switch. These are arranged electrically in parallel with one another in the high-voltage battery unit. Likewise, a plurality of low-power connections can be provided in the high-voltage high-power network, which can each be switched off via a network isolating switch designed as a semiconductor switch. Here, too, the mains circuit breakers are arranged electrically parallel to one another. Still other embodiments provide in the high-voltage battery unit one or more low-power connections in the high-voltage battery unit that can each be switched via an assigned mains circuit breaker and additionally one or more low-power connections that can each be switched via an assigned mains circuit breaker in the high-voltage high-power network.

The mains circuit breakers can each be controlled via a monitoring circuit which is arranged in or on the high-voltage low-power network and which monitors a current in the high-voltage low-power network at the low-power connection, for example.

In a further development it is provided that at least the mains circuit breakers arranged in the high-voltage battery unit are also opened in the protected state. As a result, the loads connected in the high-voltage, low-power network and the high-voltage, low-power network can be protected from excessive current loads. This also applies analogously to mains circuit breakers that are not arranged in the high-voltage battery unit, but rather between the high-voltage, high-power network and a high-voltage, low-power network.

The advantage of using mains circuit breakers designed as semiconductor switches is that no additional irreversible isolating fuses have to be used in order to secure and protect the corresponding high-voltage, low-power networks. After a fault condition in the associated high-voltage low-power network, this can thus be put back into operation. Not every malfunction due to a current peak, which is caused by a defective consumer or a consumer that is not working according to the specifications, always leads to maintenance costs.

Preferred embodiments therefore provide that no irreversible fuse is arranged in the high-voltage lines between the high-voltage, high-power network and the high-voltage, low-power network.

Particularly preferred are embodiments in which no irreversible fuses are formed in the high-voltage lines outside the high-voltage battery in the high-voltage battery unit apart from the pyrotechnic fuse, which is arranged between one battery pole and the first switching element designed as a semiconductor switch. Excluded from this are fuses that are designed in individual high-voltage loads or are provided to protect such individual loads.

Thus, no irreversible fuses are preferably formed between the battery poles and the connection poles of the connection and/or between the battery poles and the charge connection poles of the DC voltage charge connection and/or between the battery poles and the connection poles of the connection.

• 1 eine schematische Darstellung eines Hochspannungsbatteriesystems eines als Plug-in-Hybrid ausgebildeten Fahrzeugs; und
• 2 eine schematische Darstellung eines Hochspannungsbatteriesystems eines Elektrofahrzeugs.

The invention is explained in more detail below with reference to a drawing. Here show:

• 1 a schematic representation of a high-voltage battery system designed as a plug-in hybrid vehicle; and
• 2 a schematic representation of a high voltage battery system of an electric vehicle.

In 1 a high-voltage battery system 1000 of a vehicle 1 is shown schematically. The High Voltage Battery System 1000 comprises a high-voltage battery unit 100, which is arranged in a rear carriage 3 in the illustrated embodiment. The high-voltage battery unit 100 is sometimes also referred to here as the battery unit 100 for short. The high-voltage battery unit 100 includes a high-voltage battery 200 with a battery pole 210 and another battery pole 220. When the high-voltage battery 200 is charged, a high voltage in the form of a DC voltage drops between the one battery pole 210 and the other battery pole 220.

A DC voltage with a potential difference greater than 60 V is considered high voltage. As a rule, the voltage difference between one battery pole 210 and the other battery pole 220 when the high-voltage battery is charged is in the range of several 100 V, for example in the range between 300 V and 1,000 V, particularly preferably in the range between 500 V and 800 V In the case of plug-in hybrid vehicles with high-voltage batteries that have capacities of several kilowatt hours, extremely high currents of over 10 kA can occur in the event of a short circuit.

Therefore, the high-voltage battery unit 100 includes a protection circuit 300 in addition to the high-voltage battery 200 . The high-voltage battery unit encloses the high-voltage battery 200 and the protection circuit 300 and mechanically and electrically protects them from the environment. In addition, however, the high-voltage battery unit 100 has at least one connection 400 with a connection pole 410 and another connection pole 420, via which electrical energy can be removed from the electric high-voltage battery 200 at the rated discharge power and/or at the rated feed-in power into the high-voltage battery 200. One battery pole 210 is thus electrically connected to one connection pole 410 and the other battery pole 220 is electrically connected to the other connection pole 420 of connection 400 via protective circuit 300 . The at least one connection 400 is also referred to as a nominal power connection 401 or a high-performance connection. When the terms nominal discharge power and nominal feed power are used, these terms always refer to the high-voltage battery 200 of the high-voltage battery unit 100.

A high-voltage, high-performance grid 800 is connected to the at least one connection 400, with a first high-voltage, high-performance grid connection contact 810 having one connection pole 410 of the at least one connection 400, and a second high-voltage, high-performance grid connection contact 820 having the other connection pole 420 of the at least one connection 400 is connected.

In the event of damage, for example in the event of an accident, in which one or more insulation damage can occur, for example in a high-voltage high-performance network 800 which is connected to the connection 400, the protective circuit 300 is used to prevent high short-circuit currents and to switch all components free of voltage designed to galvanically isolate one battery pole 210 from one connection pole 410 and the other battery pole 220 from the other connection pole 420 in a so-called protection state. The protective state is thus brought about, for example, in the event of an accident in which there is a risk of damage to the high-voltage battery system 1000 or components thereof.

The determination of whether or not the protective state is to be established is generally determined using signals from an airbag control unit. If the airbag control device generates a triggering signal for at least one airbag, the protective state of the protective circuit is generally brought about and thus the galvanic isolation of the battery poles 210, 220 from all consumers connected thereto in the protective circuit 300 is established.

For this purpose, the protective circuit 300 comprises a first switching element 310, which interrupts the electrical line between one battery pole 210 and one connection pole 410, and a second switching element 320, which interrupts the electrical line between the other battery pole 220 and the other connection pole 420. One first switching element 310 is in the form of a semiconductor switch 313 . This offers the advantage that it is possible to change from the closed switching state to the open switching state in a very short period of time. Typical switching times are in the range of a few 100 ns. This limits the build-up of high currents to a few 100 A in the event of a double insulation fault in the high-voltage battery system. The second switching element 320, on the other hand, is embodied as a contactor 324 and separates the other battery pole 220 from the other connection pole 420.

While the second switching element 320 designed as a contactor 324 causes a galvanic isolation between the other battery pole 220 and the other connection pole 420 in the open state, the first separating element 310 embodied as a semiconductor switch 313 does not ensure this galvanic isolation. There is therefore an additional switch element between one battery pole 210 and one ment 310, ie between the one battery pole 210 and the semiconductor switch 313, a pyrotechnic fuse 315 is arranged. When the protective state is brought about, a propellant charge is ignited in pyrotechnical fuse 315, which reliably cuts through an electrical line in the pyrotechnical fuse, so that galvanic isolation is ensured.

Due to the fact that the first switching element 310, which is designed as a semiconductor switch 313, interrupts the circuit of the high-voltage battery system 1000 in a short period of time, currents that occur in the event of damage are limited to a few 100 V. In this way it can be reliably ensured that the contactor 324 also opens in the load state and brings about a galvanic isolation and welding of the contacts can be ruled out.

As a further advantage of this solution, the design of the high-voltage high-power network 800 can be adapted accordingly to the lower currents that occur and, for example, the line cross-section of lines can be reduced.

In the embodiment shown, in which the high-voltage battery unit 100 is arranged in the rear section 3 , the consumers 860 of the high-voltage high-performance network 800 are arranged in the front section 2 of the vehicle 1 . In the exemplary embodiment, a consumer 860 is a combination device 861 made up of a pulse-controlled inverter and a direct current/direct current on-board converter (DC/DC on-board converter). A low-voltage vehicle electrical system (not shown) is coupled to the combination device 861 . This is made available via the DC voltage/DC voltage vehicle electrical system converter configured in combination device 861, which is available for charging capacitances in the high-voltage, high-performance network before first switching element 310 and second switching element 320 are closed in a normal operating state , to draw power from or feed power into the high-voltage battery 200 of the high-voltage battery pack 100 . This process is referred to as intermediate circuit pre-charging. In particular, capacitances in filters (not shown) are precharged to the high voltage.

An electric machine 870 for driving the vehicle 1 is connected to the pulse-controlled inverter component of the combination device 861 . Recuperation energy can also be obtained via this during deceleration and fed back into the high-voltage battery 200 of the high-voltage battery unit 100 .

In the embodiment shown, in addition to the high-voltage, high-power network 800, there is also a high-voltage, low-power network 700, in which further electrical loads 760 are supplied with high-voltage direct current. The other loads 760 include, for example, a charger 761, an electric air conditioning compressor 762 and a high-voltage heater 763. In the illustrated embodiment, the electric air conditioning compressor 762 and the high-voltage heater 763 are coupled to the high-voltage low-power network 700 via the charger 761. The high-voltage, low-power network 700 differs from the high-voltage, high-power network 800 in that, for example, the line cross-sections are designed for lower currents.

In order to prevent excessive currents from occurring in the high-voltage, low-power network 700 , at least one low-power connection pole 780 of the high-voltage, low-power network can be separated from the high-voltage, high-power network 800 via a network isolating element 750 . The isolating element 750 is in the form of a semiconductor switch and is referred to as a mains isolating switch 353 . The grid circuit breaker 753 is actuated via a monitoring circuit (not shown) if, for example, in the high-voltage, low-power grid 700, the current exceeds a predetermined current threshold. The monitoring circuit can also monitor other parameters in order to open the mains circuit breaker 753 or to close it again in the operating state.

All electrical loads and the high-voltage battery unit 100 are connected via potential equalization lines 600 to a potential equalization component 601, which is formed, for example, by the metallic components of the motor vehicle. The equipotential bonding component and the equipotential bonding lines 600 are able to carry a short-circuit current without being damaged as a result.

In vehicle 1 designed as a plug-in hybrid, the battery can be charged by operating electric machine 870 as a generator if it is operated mechanically by an internal combustion engine (not shown) or a different type of machine. In addition, the high-voltage battery 200 can preferably be charged with two- or three-phase AC voltage from the normal low-voltage AC grid 3000, which is typically between 110 V and 250 V for a two-phase grid and between 300 V and 500 V for a three-phase grid. The 761 charger is used for this, which / three-phase current into direct current and carries out a voltage adjustment in high voltage.

In addition, however, it is also desirable to charge the high-voltage battery 200 in a short time by direct current at a high voltage, for example, a high voltage of several hundred V, i.e., on the order of the rated voltage of the high-voltage battery. For this purpose, a DC voltage charging connection 500 is formed on the high-voltage battery unit 100 . This has a charge connection pole 510 and another charge connection pole 520 .

If the DC voltage charging connection 500 is not used, then all poles of this voltage must be switched off. For this purpose, the protective circuit 300 has a further first switching element 330 and a further second switching element 340 . The one charge connection pole 510 is thus connected to the one battery pole 210 via the series-connected pyrotechnic fuse 315 and the one further switching element 330 . This additional first switching element 330 is in the form of an additional semiconductor switch 333 . The other charge connection pole 520 of the DC voltage connection 500 is connected to the other battery pole 220 via the further second switching element 340 which is designed as a further contactor 344 . When the DC charging terminal 500 is not used, the further first switching element 330, i.e. the further semiconductor switch 333, and the further second switching element 340, i.e. the further contactor 344, are in an open state. Only for the high-voltage DC charging, the further first switching element 330, i.e. the further semiconductor switch 333, and the further second switching element 340, i.e. the further contactor 344 are switched to the closed state. After the charging process has ended or in the event of a fault, the further second switching element and the further first switching element are brought into the open state.

In this embodiment, the switching elements embodied as contactors 324, 344, i.e. the second switching element 320 and the further second switching element 340, are arranged parallel to one another, as are the first switching element 310 and the further first switching element, which are each embodied as semiconductor switches 313, 333. In addition to pyrotechnic fuse 315, no irreversibly separating switching and/or safety elements are formed in the high-voltage lines of the high-voltage battery unit outside of high-voltage battery 200. Only the pyrotechnic fuse 315 irreversibly separates a line segment in the event that the protective state is brought about.

The advantage of the described embodiment is that even in the event of damage when opening the corresponding switching elements in the load state, no damage occurs to them, since one of the switching elements is either the first switching element 310 or the further first switching element 330, each of which is embodied as a semiconductor switch 313 or 333 switch in such a short period of time that damage also to the second switching elements designed as a contactor, the one second switching element 320 and the other second switching element 340, i.e. the contactors 324 and 344, does not occur. Another advantage of this circuit arrangement in the protection circuit 300 is that the DC voltage charging can take place with high-voltage direct current via the DC voltage charging connection 500 without the high-voltage high-power grid 800 being supplied with high voltage from the high-voltage battery 200 . This means that the one first switching element 310 and the second switching element 320 can be kept in the open state during DC voltage charging. As a result, a load on these switching elements is reduced and, at the same time, a power requirement that is required to operate these switching elements is reduced.

The charge connection poles 510, 520 of the high-voltage battery unit 100 must be electrically isolated from the battery poles 210 and 220, for example, if a short circuit occurs in the charging cable that connects the DC voltage charge connection 500 to a charging station 2500. In this case, too, the protective circuit 300 brings about the protective state. This means that on the one hand the pyrotechnic fuse 315 is triggered and all switching elements 310, 320, 330, 340 of the protective circuit 300 are brought into the open position.

Also in the high-voltage supply of the high-voltage low-power network 700 there are no irreversibly separating safety or switching elements in the high-voltage high-power network 800 or the high-voltage battery unit 100, apart from the pyrotechnical fuse 315.

In 2 a high-voltage battery system 1000 of a vehicle 1 designed as a purely electric vehicle is shown schematically. Identical technical components are provided with the same reference symbols and are not explained again here. The embodiment after 2 differs on the one hand by the components of the high-voltage high-power network and by the arrangement of the low-power connection 470. In the embodiment according to FIG 2 the low power terminal 470 is part of the high voltage battery pack 100. Correspondingly For example, the isolation element 350 associated with the low-power terminal 470 is formed in the protection circuit 300 of the high-voltage battery unit 100 . This mains isolating element 350 is designed as a semiconductor switch and is referred to as a mains isolating switch 353 . The mains disconnection element 350 is arranged between the one low-power connection pole 480 and the one first disconnection element 310 . One battery pole 210 is connected to the one low-power connection pole 480 via the pyrotechnic fuse 315, the one first switching element 310 and the mains isolating element 350, the pyrotechnic fuse, the one first switching element 310 and the mains isolating element 350 being connected in series in the order given. The other battery pole 220 is electrically connected to the other low-power connection pole 490 only via the second switching element, which is designed as a contactor 324 .

In the high-voltage low-power network 700, which is connected to the low-power terminal 470, a high-voltage heater 763, an electric air-conditioning compressor 762, a high-voltage battery heater 765, a DC voltage/DC voltage converter 766, an AC voltage/DC voltage Converter 767 coupled to an AC charging socket 770 and charging device 778 for automatic wireless charging. These are each electrically connected to the high-voltage low-power grid 700 in parallel with one another.

In the illustrated embodiment, the high-voltage, high-performance network 800 comprises a traction network distributor 862, via which a rear drive unit 880 and, optionally in a four-wheel drive vehicle 1, a front drive unit 890 are supplied with electrical energy. The rear drive unit 880 includes a pulse-controlled inverter 881 and an electric machine 882, which drives the rear axle wheels, for example. The front drive unit 890 includes a further pulse-controlled inverter 891 and a further electric machine 892, which drives the front axle wheels, for example. It will be appreciated by those skilled in the art that rear drive unit 880 and front drive unit 890 may each include multiple electric machines that drive individual wheels on respective axles.

In addition, an auxiliary unit distributor 866 can be provided in the high-voltage high-performance network 800 , which supplies additional high-voltage components, such as an additional high-voltage heater 867 , with electrical energy from the high-voltage battery 100 . The additional high-voltage heater 867 is individually protected from the high-voltage high-power network 800 via fuses 868 .

The DC voltage network 1500, which is connected to the DC voltage charging connection 500, leads to a DC voltage charging socket 900.

Otherwise, the embodiment is the same 1 . The advantage of this embodiment is that all high-voltage networks, the high-voltage high-performance network 800, the DC voltage charging network 1500 and the high-voltage low-power network 700 are all connected to the high-voltage battery unit 100 and the respective connection poles are all poles electrically isolated from the high-voltage battery 200 in the protective state. Thus, in the protection state, there is no high voltage outside the high-voltage battery unit 100 .

While only one high-voltage, low-power network is shown in each of the two illustrated embodiments, other embodiments can include multiple high-voltage, low-power networks, each of which has an associated network isolating element, which is designed as a semiconductor switch in the form of a network isolating switch. The low-power connections can be formed in any combination both in the high-voltage battery unit and on the high-power high-voltage network. The networks themselves (with the exception of the pyrotechnic fuse) are only connected to the high-voltage battery 200 so that they can be separated from them with reversibly switching switching elements. The pyrotechnic fuse is particularly preferably assigned to one battery pole 210 which has a higher DC voltage potential than the equipotential bonding. This is usually the positive terminal of the high voltage battery.

It is clear to the person skilled in the art that the high-voltage low-power network connection can also be formed in the high-voltage battery unit in the high-voltage battery system of a hybrid vehicle. Likewise, in a purely electrically powered vehicle, a high-voltage, low-power grid can be connected to the high-voltage battery unit and the high-voltage battery via the high-voltage, high-power grid.

Reference List

1

vehicle

2

front car

3

rear car

100

(High voltage) battery unit

200

high voltage battery

210

a battery pole

220

different battery pole

300

protection circuit

310

first switching element

313

semiconductor switch

315

pyrotechnic fuse (pyrofuse)

320

second switching element

324

contactor

330

further first switching element

333

further semiconductor switch

340

further second switching element

344

another contactor

350

mesh divider

353

Mains circuit breaker designed as a semiconductor switch

400

connection

401

rated power connection

410

a connection pole

420

other connection pole

470

low-power connector

480

a low power connector

490

other low-power connector

500

DC charging connection

510

a charge terminal

520

other charge terminal pole

600

equipotential bonding line

601

equipotential bonding component

700

high-voltage low-power grid

750

mesh divider

753

(designed as a semiconductor switch) mains circuit breaker

760

high voltage consumers

761

charger

762

air conditioning compressor

763

high voltage heater

765

high voltage battery heater

766

DC/DC converter

767

AC/DC converter

770

AC charging socket

778

Charging device for automatic wireless charging

780

low power connector pin

800

high-voltage high-power grid

810

first (high-voltage, high-power grid) connection contact

820

second (high-voltage, high-power grid) connection contact

860

(High-voltage) consumers

861

combination device

862

traction network distributor

866

accessory distributor

867

another high-voltage heater

868

fuses

870

electric machine

880

rear drive unit

881

pulse inverter

882

an electric machine

890

front drive unit

891

further pulse inverter

892

another electrical machine

900

DC charging socket

1000

high voltage battery system

1500

DC network

2500

charging station

3000

low-voltage AC power grid

Claims (11)

High-voltage battery unit (100) with a high-voltage battery (200), which has a battery pole (210) and another battery pole (220), between which a high voltage drops when the high-voltage battery (200) is charged, and a protective circuit (300) for all-pole galvanic Separating the two battery poles (210, 220) from connection poles (410, 420) of at least one connection (400) of the high-voltage battery unit (100) in a protective state, the protective circuit (300) having at least one first switching element (310) and at least one second switching element ( 320), wherein the at least one first switching element (310) is designed as a semiconductor switch (313) and the at least one second switching element (320) is designed as a contactor (324), wherein the at least one first switching element is designed as a semiconductor switch (313). (310) is arranged between the one battery pole (210) and the one connection pole (410) of the at least one connection (400) and the at least one second switching element (320) designed as a contactor (324) between the other battery pole (220) and the other connection pole (420) of the at least one connection (400) and additionally between the one battery pole (210) and the first switching element (310) designed as a semiconductor switch (313) a pyrotechnic fuse (315) for interrupting an electrical line between the one Battery pole (210) and the at least one first switching element (310) designed as a semiconductor switch (313) is arranged in the protected state, characterized in that the high-voltage battery unit (100) has at least one DC voltage charging connection (500) with a Charge connection pole (510) and another charge connection pole (520), wherein the protective shell Device (300) has at least one further first switching element (330) and at least one further second switching element (340) for all-pole disconnection of the charge connection poles (510, 520) of the DC voltage charge connection (500) from the battery poles (210, 220) in a separated state, wherein the at least one further first switching element (330) is designed as a further semiconductor switch (333) and is arranged between the pyrotechnic fuse (315) and the one charge connection pole (510) of the at least one DC voltage charge connection (500) and the at least one further second switching element ( 340). ) of the at least one DC voltage charging connection (500) with the m at least one further first switching element (330) no other switching element and no irreversible fuse is connected in series and between the other battery pole (220) and the other charge connection pole (520) of the at least one DC voltage charge connection (500) with the at least one further second switching element (340 ) no other switching element and no irreversible fuse is connected in series. High Voltage Battery Pack (100) to claim 1 , characterized in that the at least one connection (400) is a rated power connection (401) for drawing electrical energy at a rated discharge power from the high-voltage battery (200) and/or feeding electrical energy into the high-voltage battery (200) at a rated charging power in the high-voltage battery (200) is formed. High Voltage Battery Pack (100) to claim 2 , characterized in that in addition to the at least one connection (400) designed as a nominal power connection (401), at least one low-power connection (470) is designed in the high-voltage battery unit, the at least one low-power connection (470) for drawing electrical energy from the high-voltage battery (200 ) is designed below a nominal power draw and/or feeding electrical energy into the high-voltage battery (200) with an electrical power below the nominal feeding power, wherein a separating element (350; 750) assigned to the at least one low-power connection (470) is formed in the protective circuit (300). is to interrupt an electrical connection between the high-voltage battery (200) of the high-voltage battery unit (100) and a low-power terminal pole (480) of the at least one low-power terminal (470) in a fault condition, wherein the disconnecting element (350; 750) ei n mains isolating switch (353; 753) and is arranged electrically in series with the at least one first switching element (310) designed as a semiconductor switch (313) and electrically between this at least one first switching element (310) and the low-power connection pole (480) of the at least one low-power connection (470). High voltage battery unit (100) according to one of the preceding claims, characterized in that one battery pole (210) is a positive pole of the high voltage battery (200) and the other battery pole (220) is a negative pole of the high voltage battery (200). High-voltage battery unit (100) according to one of the preceding claims, characterized in that in addition to the pyrotechnic fuse (315) between the one battery pole (210) and the at least one first switching element designed as a semiconductor switch (313) in the high-voltage lines between the battery poles (210, 220 ) and the connection poles (410, 420) of the connection (400) and/or between the battery poles (210, 220) and the charge connection poles (510, 520) of the DC voltage charge connection (500) and/or between the battery poles (210, 220) and no irreversible fuses are formed on the connection poles (410, 420) of the connection (400). High-voltage battery system (1000) with at least one high-voltage battery unit (100), which a high-voltage battery (200), which has two battery poles (210, 220), between which a high voltage drops when the high-voltage battery (200) is charged, and a protective circuit (300) for all-pole galvanic isolation of the two battery poles (210, 220) from connection poles (410, 420) at least one terminal (400) comprising at least one high-voltage battery unit (100) in a protective state, wherein the protective circuit (300) comprises at least one first switching element (310) and at least one second switching element (320), and a high-voltage High-power network (800) via which at least one high-voltage consumer (860) is electrically connected, the high-voltage high-power network (800) having at least one first connection contact (810) and at least one second connection contact (820), the high-voltage high-power network (800) is connected to the at least one port (400) in such a way that the at least one first Connection contact (810) is electrically connected to the one connection pole (410) and the at least one second connection contact (820) is electrically connected to the other connection pole (410), the at least one first switching element (310) being a semiconductor switch (313) and the at least one second switching element (320) is designed as a contactor (324), the at least one first switching element (310) designed as a semiconductor switch (313) being arranged between the one battery pole (210) and the one connection pole (410) of the at least one connection (400). and that at least one second switching element (320) designed as a contactor (324) is arranged between the other battery pole (220) and the other connection pole (420) of the at least one connection (400) and additionally between the one battery pole (210) and the a pyrotechnic fuse (315) is arranged in at least one first switching element (310) designed as a semiconductor switch (313), characterized in that that the at least one high-voltage battery unit (100), in addition to the at least one connection (400), has at least one DC voltage charge connection (500) with a charge connection pole (510) and another charge connection pole (520), the protective circuit (300) having at least one further first switching element ( 330) and at least one further second switching element (340) for all-pole disconnection of the charge connection poles (510, 520) of the DC voltage charging connection (500) from the battery poles (210, 220) in a separated state, the at least one further first switching element (330) is designed as a further semiconductor switch (333) and is arranged between the pyrotechnical fuse (315) and the one charge connection pole (510) of the at least one DC charge connection (500) and the at least one further second switching element (340) is designed as a further contactor (344). , which is between the other battery pole (220) and the other charge connection pole (520) of the at least one DC voltage charge connection (500) is arranged, with no other switching element between the pyrotechnical fuse (315) and the one charge connection pole (510) of the at least one DC voltage charge connection (500) with the at least one further switching element (330) and no irreversible fuse is connected in series and no other switching element and no irreversible fuse is connected in series between the other battery pole (220) and the other charge connection pole (520) of the at least one DC voltage charge connection (500) with the at least one further second switching element (340). . High voltage battery system (1000) after claim 6 , characterized in that at least one low-power connection (470) is designed for the additional connection of at least one high-voltage low-power network (700), the at least one high-voltage low-power network (700) being designed to supply at least one further high-voltage consumer (760) with electrical energy, wherein the at least one high-voltage, low-power grid (700) has a lower rated power for energy withdrawal and/or feed-in than the high-voltage, high-power grid, wherein a grid disconnecting element (350; 750) is assigned to the at least one low-power connection (470) in order to establish an electrical connection between to interrupt the high-voltage battery (200) of the at least one high-voltage battery unit (100) and a low-power connection pole (780) in a fault state and to be able to disconnect the high-voltage low-power network (800), the network disconnecting element (350; 750) being a Hal mains circuit breaker (353; 753) is. High voltage battery system (1000) after claim 7 , characterized in that the at least one low-power connection (470) is formed in the high-voltage battery unit (100) and the isolating switch (353) is formed in the protection circuit (300) of the at least one high-voltage battery unit (100) and is electrically in series with the at least one as Semiconductor switch (313) formed first switching element (310) and electrically between this at least one first switching element (310) and the at least one low-power connection (470) is arranged. High voltage battery system (1000) after claim 7 , characterized in that the at least one low-power connection (470) is formed in or on the high-voltage high-power grid (800) and the grid circuit breaker (753) is arranged between the high-voltage high-power grid (800) and the high-voltage low-power grid (700) in order to an electrical line to be able to separate the high-voltage high-power network (800) with the high-voltage low-power network (700) in the fault state. High voltage battery system (1000) after claim 9 , characterized in that no irreversible fuse is arranged between the high-voltage high-power network (800) and the high-voltage low-power network (700) in the high-voltage lines. High voltage battery system (1000) according to any of Claims 6 until 10 , characterized in that, apart from the pyrotechnic fuse (315), which is arranged between the one battery pole (210) and the at least one first switching element (310) designed as a semiconductor switch (313), in the high-voltage lines outside the high-voltage battery (200) no irreversible fuses are formed in the at least one high-voltage battery unit (100).

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