DE102020204392A1 - Transfer device, method for operating a transfer device and vehicle - Google Patents

Abstract

The invention relates to a recharging device for a battery, a method for operating a recharging device and a vehicle, the battery comprising a series connection of at least two battery cells (BT1, ..., BT12), with a positive pole of each uneven battery cell (BT1, BT3, ..., BT11) and a negative pole of each straight battery cell (BT2, BT4, ..., BT12) of the series connection of all battery cells (BT1, ..., BT12) or a first subset of these battery cells (BT1, ..., BT12 ) can be connected to a first connecting line (BL1) via a switching element (S1, ..., S12), with a plus pole of each even battery cell (BT2, BT4, ..., BT12) and a minus pole of each odd battery cell (BT1, BT3 , ..., BT11) the series connection of all battery cells (BT1, ..., BT12) or the first subset of these battery cells (BT1, ..., BT12) via a switching element (S1, ..., S12) with another Connecting line (BL2) can be connected, the transfer device (1) having at least one first Uml adezweig (2) with at least one capacitive element, the first connecting line (BL1) being connectable via a first changeover switching element (WS1) to a first connection (A1) as well as to a further connection (A2) of the transfer branch (2), wherein the further connection line (BL2) can be connected via a further changeover switching element (WS2) to the first connection (A1) as well as to the further connection (A2) of the transfer branch (2), with a connection line-side connection of the first changeover switching element (WS1) via a first inductive connection element (VL1) is connected to the first connection line (BL1) and / or a connection line-side connection of the further changeover switching element (WS2) via a further inductive connection element (VL2) with the further connection line (BL2).

Description

The invention relates to a recharging device for a battery and a method for operating such a recharging device. The invention also relates to a vehicle with such a reloading device.

the US 10,446,880 B2 discloses a device for balancing a battery stack with two or more battery modules using a resonance circuit.

the DE 10 2010 029 015 A1 discloses a circuit for a battery which enables inductive cell balancing with reduced circuit complexity.

the US 10,396,569 B2 discloses a system for battery cell balancing using LC resonance.

The post-published DE 10 2018 221 099.3 discloses a recharging device for a battery, a recharging branch comprising a series connection of at least one capacitive element and at least one inductive element.

The technical problem arises of creating a recharging device for a battery, a method for operating such a recharging device and a vehicle with such a recharging device that ensure recharging with a high recharging current and thus rapid recharging.

The solution to the technical problem results from the subjects with the features of the independent claims. Further advantageous refinements of the invention emerge from the subclaims.

A charging device for a battery is proposed, the battery comprising a series connection of at least two battery cells. The battery preferably comprises a series connection of more than two battery cells, in particular three, four, five, six, seven, eight or nine or more than nine battery cells. The series connection can include an odd number of battery cells or an even number of battery cells.

The battery can in particular form a vehicle battery or part of a vehicle battery. The vehicle battery can in particular be a traction battery which is used to provide energy for operating an electrical machine to drive the vehicle.

A positive pole of each odd battery cell and a negative pole of each even battery cell of the series connection of all battery cells or each odd battery cell of a series connection of a first subset of these battery cells can be connected to a first connecting line via a switching element. A first subset can include several, but not all, battery cells of the battery, the battery cells of the first subset, however, being battery cells connected in series.

An odd battery cell here designates a battery cell with an odd ordinal number, the ordinal number denoting the placement of the battery cell in the order of the battery cells connected in series. In other words, the ordinal number is used to identify the point at which the battery cell is located within the row of battery cells connected in series. An odd battery cell is, for example, the first battery cell in the series connection, the third battery cell in the series connection, the fifth battery cell in the series connection, etc. Correspondingly, an even battery cell designates a battery cell with an even ordinal number. A straight battery cell is e.g. the second battery cell in the series connection, the fourth battery cell in the series connection, the sixth battery cell in the series connection, etc.

It is possible for each positive pole of each odd battery cell and each negative pole of each even battery cell to be connectable to the first connecting line via a respective switching element, the switching elements being formed separately from one another. However, if a negative pole of an even battery cell is connected to a positive pole of an odd battery cell, then these poles can be connected to the first connecting line via a common switching element.

Furthermore, a positive pole of every even battery cell and a negative pole of every odd battery cell of the series connection of all battery cells or every even battery cell of the first subset of these battery cells can be connected to a further connecting line, i.e. a second connecting line, via a switching element.

It is possible that all positive poles of every even battery cell and all negative poles of every odd battery cell can be connected to the further connecting line via switching elements which are designed separately from one another. If, however, a negative pole of an odd battery cell is connected to a positive pole of an even battery cell, then these poles can be connected to the further connecting line via a common switching element.

The number of switching elements can thus be one greater than the number of battery cells connected in series.

In the context of this invention, “connected” means that the elements connected to one another can be electrically connected, in particular directly connected. A direct connection can refer to a connection via an electrical connection element, e.g. a line, but not via an electrical or electronic component.

The recharging device here comprises the explained switching elements for connecting the poles of the battery cells to the corresponding connecting lines.

The device further comprises the connecting lines explained.

The reloading device further comprises at least one first reloading branch, which can also be referred to as the first reloading section. Here, a first connection of the transfer branch is connectable or connected, in particular permanently connected, to the first connecting line, in particular via exactly or at least one switching element. Furthermore, a further connection of the transfer branch can be connected to the further connection line, in particular via exactly one or at least one further switching element, or connected, in particular permanently connected.

The first and the further connecting line, which can also be referred to as the second connecting line, are in this case designed as connecting lines that are different from one another.

The first and the further connection of the transfer branch are different connections of the transfer branch. The transfer branch can thus comprise an entirety or an overall circuit of electrical or electronic components which is arranged between the first and the further connection of the transfer branch.

The recharging device further comprises at least one first recharging branch with at least one capacitive element. The transfer branch preferably comprises a series connection of at least one capacitive element and at least one inductive element. The fact that the transfer branch comprises a component can mean that the transfer branch also comprises further electrical or electronic components in addition to this component. A capacitive element can in particular be designed as a capacitor. An inductive element can in particular be designed as a coil. A resonant circuit is formed by connecting at least one capacitive and at least one inductive element in series.

The capacitive element of the recharging branch can also be referred to as a recharging capacitor. This capacitive element serves as an intermediate store for electrical energy / charge during the charge equalization. A process for the charge equalization between different battery cells can include a discharging process and a charging process.

For example, it is possible to transport charge from one or more battery cells into the capacitive element in one discharge process, in particular via a corresponding current flow. After this transport has ended, electrical energy / charge can then be transported in a charging process from the capacitive element of the transfer branch into one or more battery cell (s), in particular also via a corresponding current flow. A battery cell, from which electrical energy is transported into the capacitive element of the transfer branch during the discharge process, is preferably not part of the battery cells into which electrical energy / charge is transported from the capacitive element of the transfer branch during the charging process. All battery cells from which electrical energy / charge is transported into the capacitive element of the transfer branch in the discharge process are preferably different from the battery cells into which electrical energy / charge is transported from the capacitive element of the transfer branch during the charging process.

The presence of the inductive element in the recharging branch results in an advantageous manner that no undesirably high currents can occur during the discharging process or the charging process. This advantageously ensures that the transfer device can be operated in an improved manner.

The recharging device can of course comprise at least one control device for controlling the switching elements, in particular for setting switching times of the switching elements. This control device can be designed as a computing device or comprise such a device. A computing device can in particular be designed as a microcontroller or as an integrated circuit, for example as an FPGA.

The reloading device can further comprise an evaluation device. The evaluation device and the explained control device can be designed as a common device. The evaluation device can also be designed as a computing device or comprise such a device. Means the evaluation device can be evaluated in more detail below.

It is possible for the first connection to be connectable both to the first connection line and to the further connection line, in particular by means of a switching element, e.g. by means of a changeover switching element. However, the first connection cannot be connected to both the first and the further connecting line at the same time. In other words, a first connection that can be connected to the first and further connecting lines can be connected in a first state to the first connecting line, but not to the further connecting line, and in a further state to the further connecting line but not to the first connecting line. As will be explained in more detail below, however, it is also possible, in particular, for the first connection to be connectable or connected to the first connection line but not to the further connection line. In other words, this can mean that the recharging device is configured in such a way that no electrical connection can be established between the first connection and the further connecting line.

Accordingly, it is possible for the further connection to be connectable both to the first connection line and to the further connection line, in particular by means of a switching element, e.g. by means of a changeover switching element. However, the further connection cannot be connected to both the first and the further connecting line at the same time. In other words, a further connection that can be connected to the first and further connecting line can be connected in a first state to the first connecting line, but not to the further connecting line, and in a further state to the further connecting line but not to the first connecting line. As will be explained in more detail below, however, it is also possible, in particular, for the further connection to be connectable or connected to the further connection line but not to the first connection line. In other words, this can mean that the recharging device is configured in such a way that no electrical connection can be established between the first connection and the further connecting line.

According to the invention, the first connection line can be connected to the first connection as well as to the further connection via a first changeover switching element. However, the first connecting line cannot be connected to both the first and the further connection at the same time. In other words, the first connection line that can be connected to the first and further connection can be connected in a first state to the first connection, but not to the further connection, and in a further state to the further connection, but not to the first connection.

Furthermore, the further connecting line can be connected to the first connection as well as to the further connection via a further changeover switching element. However, the further connecting line cannot be connected to both the first and the further connection at the same time. In other words, the further connection line that can be connected to the first and further connection can be connected in a first state to the first connection, but not to the further connection, and in a further state to the further connection, but not to the first connection.

Furthermore, according to the invention, the connection line-side connection of the first changeover switching element is connected to the first connection line via a first inductive connection element and / or a connection line-side connection of the further changeover switching element is connected to the further connection line via a further inductive connection element. An inductive connecting element can in particular be designed as a coil. In other words, the connection on the connection line side of at least one changeover switching element is connected to the corresponding connection line via an inductive connection element.

The integration of inductive connection elements in the electrical connection between the connection line-side connections of the changeover switching elements and the connection lines means that at least one battery cell can be short-circuited via at least one inductive connection element without the capacitive element of the transfer branch being arranged in the corresponding short-circuit circuit. This advantageously enables electrical energy to be temporarily stored in the form of a magnetic field generated by the inductive element, the temporarily stored energy then being able to be supplied to the capacitive element after the short circuit has ended. In this way, a high state of charge of the capacitive element can be achieved in an advantageous manner, which in turn accelerates the recharging process. It is also possible to carry out a recharging, with a voltage across the capacitive element of the recharging branch being greater than the voltage across the battery cell (s) to be discharged, which, as explained in more detail below, results in a voltage swing during the recharging process across the capacitive Element and thus also its thermal load is reduced. Further results in more advantageous Way that high recharging currents can be carried through the proposed design of the recharging branch, whereby a time period for recharging between at least two battery cells is advantageously shortened.

Furthermore, it is advantageously made possible that the reloading device does not have to include a voltage sensor for detecting a voltage across the capacitive element of the reloading branch in order to control the reloading. It is also not necessary for the recharging device to include a current sensor for detecting a current in the recharging branch in order to control the recharging. This advantageously reduces the complexity, the installation space requirement and the costs of the proposed reloading device.

In a further embodiment, the inductive connecting elements have the same inductance. This advantageously simplifies a method for operating the recharging device, in particular since no different properties of differently dimensioned inductances on the time profile of the recharging current have to be taken into account.

In a further embodiment, a changeover switching element is designed as a series connection of two transistor switches or comprises such a series connection. A transistor switch can in particular be a MOSFET or IGBT.

This advantageously results in a simple circuit design of a changeover switching element, as a result of which production costs for the production of the reloading device can be reduced while at the same time ensuring reliable operation.

In a further embodiment, the changeover switching elements are each designed as half-branches of a bridge circuit or comprise these half-branches. Thus, the entirety of the first changeover switching element and the further changeover switching element is provided by a bridge circuit with two half branches. This also advantageously results in a simple circuit implementation of the recharging device, with reliable operation being ensured.

In a further embodiment, the capacitive element of the transfer branch is designed as a polarized capacitor or comprises one. This advantageously reduces the installation space required for realizing the recharging device, since the polarized capacitors, which can also be referred to as ELKO (s), require less installation space than non-polarized capacitors with a comparable capacitance.

It is also possible that a switching element for connecting a pole of a battery cell to the first or the further connecting line is formed by at least two transistor switches connected in reverse series. A first transistor switch is connected to the pole of the battery cell and to the further transistor switch via a connecting section. The further transistor switch is then connected to a connecting line.

A transistor switch is preferably formed by a MOSFET, wherein a MOSFET can comprise an intrinsic freewheeling diode which is connected electrically in parallel to the conduction path between the drain and source of the MOSFET.

Alternatively, the transistor switch can also comprise an IGBT. If a transistor switch comprises an IGBT, the transistor switch can also comprise a freewheeling diode which is connected electrically in parallel to the conduction path between the emitter and collector of the IGBT.

Self-locking MOSFETs or IBGTs can preferably be used as transistor switches, further in particular so-called n-channel MOSFETs / IBGTS or p-channel MOSFETs / IBGTs. Alternatively, however, self-conducting MOSFETs / IBGTs can also be used, which in this case can also be designed as n-channel MOSFETs / IBGTs or p-channel MOSFETs / IBGTs.

In this case, antiserial can mean that the forward directions of the free-wheeling diodes of the two transistor switches are oriented opposite to one another. For example, the transistor switches can be connected in series with one another in such a way that the forward direction of a first transistor switch is oriented from the connecting line to the pole and the forward direction of a further transistor switch is oriented from the pole to the connecting line. Alternatively, the transistor switches can also be connected in series with one another in such a way that the forward direction of the first transistor switch is oriented from the pole to the connecting line and the forward direction of the further transistor switch is oriented from the connecting line to the pole.

In the event that the transistor switches of the switching element are formed by MOSFETs, the switching element can, for example, comprise a first MOSFET, the drain terminal of which is connected to the pole of a battery cell. The source connection of this first MOSFET can be connected to a source connection of a further MOSFET of the switching element. The drain connection of this further MOSFET can then be connected to the connecting line be connected. A forward direction of the intrinsic freewheeling diode of the respective MOSFET can be oriented from the source to the drain.

The recharging device further comprises a driver circuit with a driver voltage connection for each switching element. This driver voltage connection is used to provide the gate voltage for each transistor switch.

Furthermore, a gate connection of each transistor switch of a switching element is in each case connected to the driver voltage connection of the driver circuit of the switching element. In other words, the gate connections of all transistor switches of a switching element are connected to the same driver voltage connection. The same voltage is applied to all gate connections, which means that all transistor switches of a switching element can be switched on (i.e. switched on) or switched off (i.e. switched off) at the same time.

It is also possible that a supply voltage connection of the driver circuit of a switching element, which is connected to a negative pole of a battery cell, is electrically connected to a positive pole of the battery cell and / or that the voltage at the driver voltage connection is provided by means of a level converter and / or that the charging device has a control device for controlling the driver circuits, wherein a supply voltage connection of the control device is connected to a negative pole of the last battery cell of the series connection of all battery cells or the previously explained first subset of battery cells and / or that the positive pole of the first battery cell of the series connection of all battery cells or the first subset via a first protective line connected to the first connecting line and via a second protective line to the further connecting line, with at least one diode being arranged in each protective line and / or that the negative pole of the last battery cell of the series connection of all battery cells or the first subset is connected to the first connecting line via a third protective line and to the further connecting line via a fourth protective line, with at least one diode being arranged in each protective line.

It is also possible that the transfer branch comprises a series connection of at least one capacitive element, at least one inductive element and at least one resistive element and / or that the transfer device comprises at least one means for detecting or determining a voltage across the capacitive element of a transfer branch and at least one Comprises means for detecting or determining a voltage across the inductive element of a transfer branch. The means for detection can in particular be designed as a voltage sensor. Of course, however, the invention is not limited to voltage sensors for detecting or determining the voltage. Alternatively or cumulatively, further means known to the person skilled in the art for detecting or determining such a voltage can be used. The means for detection or determination can be connected in terms of data and / or signal technology to the evaluation device explained above. This advantageously results in an improved control of switching elements of the recharging device is made possible, namely a control as a function of the detected or determined voltage. This is explained in more detail below.

It is also possible for the reloading device to include a further reloading branch. The further transfer branch comprises a series connection of at least one capacitive element and at least one inductive element. It is also possible that the further transfer branch comprises a series connection of the at least one capacitive element, the at least one inductive element and at least one resistive element. The further transfer branch is preferably formed by one of the listed series connections. In other words, the further transfer branch is designed in accordance with the transfer branch explained above.

Furthermore, a first connection of the further transfer branch can be connected to a third connection line, in particular via a switching element, or is connected, in particular permanently connected. Furthermore, a further connection of the further transfer branch can be connected to a fourth connecting line, in particular via a switching element, or is connected, in particular permanently connected.

The third and fourth connecting lines are designed as connecting lines that are different from one another. Furthermore, these connecting lines are also different from the first and the previously explained second connecting line. As already explained with regard to the first and the second connection line, it may be possible that the first connection of the further transfer branch cannot be connected to the fourth connection line. Likewise, the further connection of the further transfer branch cannot be connected to the third connecting line. These connections cannot be connected to the first and second connecting lines either.

There is also a positive pole for every odd battery cell and a negative pole for every even battery cell Battery cells of all battery cells or a further subset of these battery cells can be connected to the third connecting line via a switching element. The further subset of battery cells comprises several series-connected battery cells of the battery. Here, however, the further subset of battery cells comprises at least one battery cell that is not part of the previously explained first subset of battery cells.

Alternatively, it is possible that a positive pole of every odd battery cell and a negative pole of every even battery cell of a further battery can be connected to the third connecting line via a switching element.

Furthermore, a positive pole of every even battery cell and a negative pole of every odd battery cell of all battery cells or the further subset of these battery cells can be connected to the fourth connecting line via a switching element.

Alternatively, it is possible that a positive pole of every even battery cell and a negative pole of every odd battery cell of the further battery can be connected to the fourth connecting line via a switching element.

A method for operating a transfer device according to one of the embodiments disclosed in this description is also proposed. Here, in a discharge state, a first section of the series connection of all battery cells is connected to the transfer branch, with a further section of the series connection of all battery cells being connected to the transfer branch in a charge state, with at least one battery cell of the first section not being part of the further section.

In this discharge state, electrical energy / charge can be transported from the battery cell (s) into the at least one capacitive element of the transfer branch. This can also be referred to as the discharge process. The discharge state can be set, for example, by activating corresponding switching elements and / or changeover switching elements. In the discharged state, in particular at least one battery cell of the first subsection can be discharged.

The first subsection of the series connection of all battery cells comprises at least one, but preferably a plurality of battery cells connected in series, of the series connection of all battery cells, but more preferably not all battery cells of the series connection. However, it is also possible for the first subsection to include exactly one battery cell.

In a state of charge, a further section of the series connection of all battery cells is connected to the transfer branch. The further subsection of battery cells here comprises at least one, but preferably a plurality of battery cells connected in series, of the series connection of all battery cells. However, it is also possible for the further subsection to include exactly one battery cell.

The first subsection preferably comprises more battery cells than the further subsection. This advantageously results in a charge equalization that is faster over time.

In this charge state, electrical energy / charge can be transported from the at least one capacitive element of the transfer branch into the battery cell (s) of the further subsection. This can also be referred to as the charging process. The state of charge can also be set, in particular by activating corresponding switching elements and / or changeover switching elements. Furthermore, at least one battery cell of the first subsection is not part of the further subsection. Preferably, no battery cell of the further subsection is a battery cell of the first subsection (and vice versa). However, it is also possible that several battery cells, but not all battery cells, of the first subsection are not part of the further subsection.

The setting of the state of discharge and the state of charge can be carried out by the control device explained above. In particular, the discharge state can be set until the at least one capacitive element of the transfer branch has reached a predetermined state of charge, in particular until the state of charge has risen to the predetermined state of charge, and / or until one or more battery cell (s) of the first subsection has a predetermined state of charge has reached, in particular until the state of charge of this battery cell (s) has fallen to the predetermined state of charge.

The state of charge can be set until one or more battery cells of the further subsection have each reached a predetermined (desired) state of charge, in particular until the state of charge of this battery cell (s) has risen to this predetermined state of charge, and / or until the state of charge of at least one capacitive element has reached a predetermined threshold value, in particular until this state of charge has fallen to the predetermined threshold value.

Here the Transfer device comprise at least one means for detecting or determining the state of charge of the at least one capacitive element of the transfer branch. Furthermore, the recharging device can comprise at least one means for detecting the state of charge of a battery cell, preferably each battery cell, of the series connection of all battery cells.

A sequence of the states “state of discharge, state of charge” or “state of discharge, idle state, state of charge” can be repeated periodically. In the mutually corresponding states of the different periods, different battery cells can be discharged or charged. For example, it is possible for one of the odd battery cells to be charged in the charge states of consecutive periods. After all of the uneven battery cells have been charged, one of the even battery cells can then be charged in each case in the charge states of further consecutive periods. Between the sequence of periods for charging the uneven battery cells and the sequence of periods for charging the even battery cells, the capacitor can be recharged in the recharging branch, which will be explained below.

Of course, it is also possible for one of the straight battery cells to be charged in each case in the charge states of consecutive periods. After all of the even battery cells have been charged, one of the odd battery cells can then be charged in each case in the charge states of further consecutive periods. The capacitor can be recharged in the recharging branch between the sequence of periods for charging the even battery cells and the sequence of periods for charging the odd battery cells.

This advantageously results in a method for carrying out a charge equalization between different battery cells of the series connection of battery cells of a battery, which method improves the guarantee of operability. In particular, the level of a charging or discharging current, that is to say of the current flowing in the discharging or charging state of the recharging device, is limited by the at least one inductive element.

In a further embodiment, the discharge state is set when a voltage across the capacitive element of the transfer branch is lower than the voltage across the first section of the series connection of all battery cells. In other words, the discharge state is set when the charge-reversal capacitor voltage is lower than the voltage of one or more battery cells connected in series. The discharge state can be set by closing switching elements to connect a pole to a connecting line and by activating the changeover switching elements.

In such a method, the first section is preferably short-circuited via the at least one inductive connection element at a first point in time, this short circuit being canceled at a later point in time, which can be referred to as the second point in time, for example. This can be done, for example, by electrically connecting the capacitive element in the transfer branch to the first subsection of the series circuit, as a result of which the discharge state is set. The period of time between the first and the second point in time can therefore precede the setting of the discharge state.

In the short-circuited state, a current flows through the at least one inductive connection element, as a result of which a voltage builds up across it. If the capacitive element in the transfer branch is then connected to the first section of the series connection of all battery cells via the inductive connection elements, the capacitive element is generated both from the first section and due to the inductive connection elements based on Lenz's rule after the short circuit has ended Charged current flow, whereby the voltage across the capacitive element can be greater than the voltage across the first section of the series circuit, for example twice as high.

At a third point in time, which can in particular be a zero current point in time, the further subsection of the series connection of all battery cells is connected to the connecting lines. The zero current point in time here denotes a point in time at which no current flows through the switching elements. At this point in time, no current can flow in the transfer branch.

At a fourth point in time, the further subsection can then be connected to the reloading branch, in particular by appropriately activating the changeover switching elements. In this state, the transfer branch can in turn be connected to the further subsection via the at least one inductive connection element. This corresponds to the previously explained state of charge. In this state of charge, a current flows from the capacitive element of the transfer branch via the at least one inductive connection element into the further subsection. At a fourth point in time, the transfer branch can then be electrically separated from the further subsection, in particular by activating the changeover switching elements. According to this, the at least one inductive connecting element can continue to drive a current on the basis of Lenz's rule after the disconnection of the recharging branch, which current flows into the further section and charges the battery cell (s) arranged therein. At a fifth point in time, the other Partial section are separated from the connecting lines, in particular by suitable control of the corresponding switching elements. The fifth point in time can also be selected as the zero current point in time, that is to say a point in time at which no current flows through the switching elements.

This advantageously results in a method for operating the recharging device which enables battery cells to be reliably recharged.

In an alternative embodiment, the discharge state is set when a voltage across the capacitive element of the transfer branch is greater than the voltage across the first section of the series connection of all battery cells.

In this embodiment too, the first subsection can be short-circuited via the at least one inductive connection element before the discharge state is set, in particular by suitable control of the changeover switching elements. Furthermore, the first subsection can be connected to the connecting lines at the first point in time, in particular by suitable control of the corresponding switching elements.

At a second point in time, the short circuit can be canceled and the charge transfer branch can be electrically connected to the first section, as a result of which the discharge state is set. As explained above, the capacitive element is then charged both from the first section and due to the current flow generated by the inductive connecting elements based on Lenz's rule after the termination of the short circuit.

At a third point in time, which is in particular a zero current point in time in the discharge state that occurs without switching the (alternating) switching elements, the first section is separated from the connecting lines and the further section is connected to the connecting lines, in particular by suitable control of the corresponding switching elements. At a fourth point in time, the transfer branch can then be connected to the connecting lines, in particular by suitable control of the changeover switching elements. At a fourth point in time, which is in particular a zero current point in time in the charging state that occurs without switching the (alternating) switching elements, the further subsection can then be separated from the connecting lines. A new charge level can then be set.

In a sub-section between the third and the fourth point in time, the current can be driven (further) by the inductive connecting elements and the battery cells of the further sub-section can be charged.

This advantageously results in an operation of the transfer device with a small voltage swing on the capacitive element of the transfer branch, a voltage swing denoting the difference between a maximum and a minimum voltage during a “state of discharge” “state of charge” cycle. This advantageously results in a low thermal load on the capacitive element of the transfer branch.

Furthermore, it results in an advantageous manner that in such an embodiment, when the changeover switching elements are designed as half-branches of a bridge circuit, when the current crosses zero in the charging state, it is not necessary to separate the further subsection from the connecting lines, since free-wheeling diodes of the transistor switching elements used in the half-branches generate a further current flow and thus a Prevent renewed discharge of the battery cells of the further subsection. Thus, there is no need to disconnect the further subsection from the connecting line after the maximum charged state has been reached, which is effected by actively driving the switching elements, so that a switching process and thus also the corresponding generation of control signals are dispensed with. This advantageously results in a simpler operation of the corresponding reloading device.

In a further embodiment, a charge reversal is recorded. The charge reversal current can be a charge current or a discharge current. As already explained above, this can be detected in particular by a means for detecting the current flowing through the transfer branch, wherein the means can in particular be designed as a current sensor. The means for detecting the charge reversal can be connected to the control and evaluation device explained above.
Switching times for switching the changeover switches and / or switching times for switching the switching elements through which poles are connected to connecting lines are then determined as a function of the current, that is to say as a function of the detected charge reversal. In particular, switching times are determined in such a way that the previously explained zero-current switching takes place, i.e. switching at a point in time at which the recharging current is zero or deviates from zero by a predetermined (small) amount, with the current flow through closed switching elements also being zero at this point in time can.

This advantageously results in improved operational reliability of the reloading device, in particular because it is ensured can ensure that the switching elements (including the changeover switching elements) are not switched under current, which increases their service life.

In an alternative embodiment, a time profile of the charge reversal current is determined as a function of electrical properties of the elements of the charge reversal device. Such electrical properties can be, for example, a capacitance, a resistance and an inductance of the elements. The elements of the reloading device can in particular be the capacitive element of the reloading branch, an inductive element in the reloading branch, e.g. the at least one inductive connecting element, the switching elements, including the changeover switching elements, and the battery cells.

It is thus possible to determine the electrical properties of a circuit closed in the recharging device, such a circuit, for example, comprising the capacitive element of the recharging branch, the at least one inductive connecting element, the switching elements and exactly one or more battery cells. The previously explained time profile of the charge reversal can then be determined. This can be done in particular on a model basis. In particular, tolerances of the elements of the reloading device can also be taken into account here.

It is also possible to detect a temperature of the at least one battery cell, an electrical property of the battery cell, in particular an (internal) resistance of the battery cell, then being determined as a function of the temperature. In other words, the electrical property of at least one element of the recharging device is determined as a function of temperature, for example using a previously known temperature model. Furthermore, the time profile of the charge reversal current can then be determined as a function of the temperature-dependent property determined in this way. As explained above, switching times for switching the toggle switches and / or switching times for switching the switching elements for connecting poles to connecting lines can then be determined as a function of the current, that is to say depending on the specific time profile as explained above. In particular, the switching times can be determined in such a way that zero-current switching is made possible.

The determination of the course over time and the switching times can in particular be carried out by the control and evaluation device explained above.

This advantageously results in an operation of the recharging device without direct current detection, as a result of which a current sensor can advantageously be dispensed with and thus manufacturing costs for manufacturing the recharging device can be reduced.

A vehicle, in particular a motor vehicle, is also proposed, the vehicle comprising a battery with a plurality of battery cells connected in series and a recharging device according to one of the embodiments described in this disclosure.

Overall, the reloading device described in this disclosure and the method for operating the reloading device can correspond to one of the subsequently published DE 10 2018 221 099.3 described embodiments or further developed, in particular one in the claims of these subsequently published DE 10 2018 221 099.3 .

• 1 ein schematisches Schaltbild einer erfindungsgemäßen Umladevorrichtung gemäß dem Stand der Technik,
• 2 ein schematisches Schaltbild einer erfindungsgemäßen Umladevorrichtung,
• 3 ein schematisches Schaltbild eines Umladezweigs in einer weiteren Ausführungsform,
• 4 ein schematisches Schaltbild einer erfindungsgemäßen Umladevorrichtung in einer weiteren Ausführungsform,
• 5 schematische zeitliche Verläufe von einer Spannung über einem kapazitiven Element im Umladezweig und einem Umladestrom entsprechend einem ersten Betriebsmodus der Umladevorrichtung und
• 6 schematische zeitliche Verläufe von einer Spannung über einem kapazitiven Element im Umladezweig und einem Umladestrom entsprechend einem weiteren Betriebsmodus der Umladevorrichtung.

The invention is explained in more detail using exemplary embodiments. The figures show:

• 1 a schematic circuit diagram of a reloading device according to the invention according to the prior art,
• 2 a schematic circuit diagram of a reloading device according to the invention,
• 3 a schematic circuit diagram of a transfer branch in a further embodiment,
• 4th a schematic circuit diagram of a reloading device according to the invention in a further embodiment,
• 5 schematic time curves of a voltage across a capacitive element in the recharging branch and a recharging current corresponding to a first operating mode of the recharging device and
• 6th Schematic temporal progressions of a voltage across a capacitive element in the recharging branch and a recharging current corresponding to a further operating mode of the recharging device.

In the following, the same reference symbols designate elements with the same or similar technical properties.

1 shows a schematic circuit diagram of a reloading device according to the invention 1 for a battery according to the prior art, the battery being a series connection of several battery cells BT1 , BT2 , BT3 , BT4 , ...., BT11 , BT12 includes. In 1 are positive poles of the battery cells BT1, ..., BT12 with a "+" sign and the negative pole of the battery cells BT1, ..., BT12 shown with a "-" sign. Also shown are battery cell voltages U1, U2, U3, U4, ..., U11, U12, where this battery cell voltage U1, ..., U12 across the respective battery cell BT1 , .. .., BT12 falls off.

Hereby form the first battery cell BT1 , the third battery cell BT3 , the fifth battery cell, the seventh battery cell, the ninth battery cell and the eleventh battery cell BT11 odd battery cells of the series connection. The second battery cell BT2 , the fourth battery cell BT4 , the sixth battery cell, the eighth battery cell, the tenth battery cell and the twelfth battery cell BT12 just form battery cells of the series connection.

The reloading device further comprises switching elements S1 , S2 , S3 , S4 , ..., S12 , S13 . In particular, the number of switching elements S1, ..., S13 the reloading device 1 that are used to establish or disconnect the electrical connection of the positive or negative poles of the battery cells BT1, ..., BT12 with a first connection line BL1 or a second connection line BL2 serve to be the number one greater than the number of series-connected battery cells BT1, ..., BT12 the battery.

In 1 is shown as having a positive pole of every odd battery cell BT1 , BT3 , ..., BT11 via a switching element S1 , S3 , ... with the first connection line BL1 is connectable. It is also shown that a negative pole of each straight battery cell of the series connection is also via a switching element S3 , ..., S13 with the first connection line BL1 is connectable. Here are the positive poles of all odd battery cells BT3 , ..., BT11 except for the first battery cell BT1 with negative poles of the straight battery cell immediately preceding in the series connection BT2 , BT4 , ... electrically connected.

It is also shown that a positive pole of every straight battery cell BT2 , BT4 , ..., BT12 via a switching element S2 , S4 , ..., S12 with the second connection line BL2 is connectable. It is also shown that the positive poles of the straight battery cells BT2 , BT4 , ..., BT12 with negative poles of the uneven battery cell immediately preceding in the series connection BT1 , BT3 , ..., BT11 are electrically connected. This also includes the negative poles of all odd battery cells BT1 , BT3 , ..., BT11 with the second connection line BL2 via switching elements S2 , S4 , ..., S12 electrically connectable.

It is also shown that the reloading device 1 a transshipment branch 2 comprises, with a capacitor in the transfer branch C. is arranged. It is possible that the transfer branch is a series connection of a capacitor C. and an inductance, for example a coil, comprises or is formed by this. Alternatively, it is possible that the transfer branch is a series connection of a capacitor C. and an inductance, for example a coil, and a resistor or is formed by these. The series connection of the resistor, the capacitor C. and the coil form an oscillating circuit, in particular a damped oscillating circuit. There is no resistance in the transfer branch 2 present, then forms the series connection in the transfer branch 2 an undamped oscillating circuit.

The transshipment branch 2 has a first port A1 and a second port A2 on. The first connection A1 is electrical with the first connection line BL1 connected, especially permanent. Next is the first connection A1 of the transshipment branch 2 not directly or immediately with the second connecting line BL2 connectable. In particular, there can be an electrical connection between the first connection A1 of the transshipment branch 2 and the second connection line BL2 only via at least one battery cell BT1, ..., BT12 getting produced.

It is also shown that the second connection A2 of the transshipment branch 2 with the second connection line BL2 connected, especially permanently.

In particular, is the second port A2 not directly or immediately with the first connection line BL1 connectable. So can the electrical connection of the second connection A2 with the first connection line BL1 (and thus with the first connection A1 ) only via at least one battery cell BT1, ..., BT12 getting produced.

A capacitor voltage is also shown UC that is above the capacitor C. of the transshipment branch 2 drops, as well as a coil voltage that is across the coil L. falls off.

A control and evaluation device is shown schematically 3 , the switching operations of the switching elements S1, ..., S13 can control. The control and evaluation device 3 can for example be designed as a microcontroller or integrated circuit. The switching elements S1, ..., S13 can be designed in particular as a power switch, further in particular as a MOSFET or IGBT.

Various states, in particular an idling state and a discharging state and a charging state, are described in the introduction DE 10 2018 221 099.3 explained.

2 shows a schematic circuit diagram of a reloading device according to the invention 1 . The transfer branch is shown 2 that is a capacitive element C. includes. A first connection A1 of the transshipment branch 2 is via a first changeover switching element WS1 with the first connection line BL1 and about another Changeover switching element WS2 with another connection line BL2 connectable. Another connection A2 of the transshipment branch 2 is via the first changeover switching element WS1 with the first connection line BL1 and via the further changeover switching element WS2 with the other connecting line BL2 connectable. In the in 2 shown state of the reloading device 1 is the first connection A1 via the first changeover switching element WS1 with the first connection line BL1 and the further connection A2 via the second changeover switching element WS2 with the other connecting line BL2 tied together. In other words, it is a connection line-side connection of the first changeover switching element WS1 via the first changeover switching element WS1 with the first or the further connection A1 , A2 of the transshipment branch 2 connectable. A connection line-side connection of the further changeover switching element WS2 is via the further changeover switching element WS2 also with the first or the further connection A1 , A2 of the transshipment branch 2 connectable.

It is also shown that the connection line-side connection of the first changeover switching element WS1 via a first inductive connecting element VL1 with the first connection line BL1 connected is. The connection on the connecting line side of the further changeover switching element is likewise WS2 via another inductive connecting element VL2 with the other connecting line BL2 tied together. The inductances of the first and the further inductive connection element VL1 , VL2 can be the same here.

It is also shown that the transfer branch 2 or a section of the transshipment branch 2 between the first and the next connection A1 , A2 does not include a separate inductive element, in particular no coil. In particular, it is between the first and the further connection A1 , A2 of the transshipment branch 2 no series connection from the capacitive element C. and a separate inductive element is provided.

Next is in 2 shown that the reloading device 1 a series connection of four battery cells BT1 , BT2 , BT3 , BT4 comprises, wherein a positive pole of the first battery cell BT1 via a first switching element S1 with the first connection line BL1 is connectable. A positive pole of the third battery cell is correspondingly BT3 via a third switching element S3 with the first connection line BL1 connectable. A positive pole of the second battery cell BT2 is via a second switching element S2 and a positive pole of the fourth battery cell BT4 via a fourth switching element S4 with the other connecting line BL2 connectable. It is also shown that a negative pole of the fourth battery cell BT4 via a fifth switching element S5 with the first connection line BL1 is connectable.

A control and evaluation device is also shown 3 through which an operation of the switching elements S1 , .. .., S5 and the changeover switching elements WS1 , WS2 can be controlled. Corresponding control signal lines are shown by a dashed line.

3 shows a schematic circuit diagram of a transfer branch 2 in a further embodiment. A first connection is shown A1 and a second port A2 of the transshipment branch 2 , with between the first and the further connection A1 , A2 a recharge capacitor C. is arranged.

It is also shown that the first changeover switching element WS2 by a series connection of two MOSFETs M1 , M2 is formed. Here is a drain connection of the first MOSFET M1 with the first connection A1 and a source terminal of the first MOSFET M1 to a drain connection of the second MOSFET M2 tied together. There is also a source connection of the second MOSFET M2 with the second connection A2 tied together. A first inductive connector VL1 is here with a connecting section of the first changeover switching element WS1 electrically connected, this being the source connection of the first MOSFET M1 to the drain connection of the second MOSFET M2 connects. The series connection of the two MOSFETs M1 , M2 forms a half branch of a bridge circuit. The further changeover switching element is corresponding WS2 from a series connection of a third MOSFET M3 and a fourth MOSFET M4 educated.

The capacitor located in the transfer branch C. can in particular be designed as a polarized capacitor.

4th shows a schematic circuit diagram of a recharging device 1 according to a further embodiment of the invention. A transfer branch is shown 2 with a capacitor C. and a coil L. connected in series. As previously explained, the transfer branch 2 also just a capacitor C. include.

A first connection is also shown A1 and a second port A2 of the transshipment branch 2 . A series connection of four battery cells is also shown BT1 , BT2 , BT3 , BT4 . A first connecting line is also shown BL1 and a second connection line BL2 .

The positive poles of every odd battery cell BT1 , BT3 the series connection of battery cells BT1 , ..., BT4 are about switching elements S1 , S3 with the first connection line BL1 connectable. The negative poles of every straight battery cell BT2 , BT4 are about switching elements S3 , S5 with the first connection line BL1 connectable. The positive poles of every straight battery cell BT2 , BT4 are about switching elements S2 , S4 with the second connection line BL2 connectable. The negative poles of every odd battery cell are correspondingly BT1 , BT3 via switching elements S2 , S4 with the second connection line BL2 connectable.

In the in 4th The embodiment shown is the first connecting line BL1 with the first connection A1 as well as with the further connection A2 by means of a first changeover switching element WS1 is connectable. The further connection line is corresponding BL2 with the first connection A1 as well as with the further connection A2 connectable, namely by means of a further changeover switching element WS2 .

The switching elements S1 , .. ., S5 , over the poles of the battery cells BT1 , .. ., BT4 with connecting lines BL1 , BL2 are connectable or via which the connection between the poles and the connecting lines BL1 , BL2 can be produced or separated, as switching elements S1 , .. ., S5 a first switching element level are designated. The switching elements WS1 , WS2 , via which an electrical connection between the connections A1 , A2 of the transshipment branch 2 and the connecting lines BL1 , BL2 can be produced or separated can be referred to as switching elements of a second switching element level.

The in 4th Shown embodiment switching elements of the first and second switching element level. In the 1 The embodiment shown here comprises switching elements of the first switching element level, but no switching elements of the second switching element level.

A control device is also shown 7th to control the operation of the switching elements S1 , .. ., S5 the first level, the control device 7th Control signals for the operation of these switching elements S1 , ..., S5 generated and via control lines CS1 , CS2 , CS3 , CS4 , CS5 this transmits. A supply voltage connection of the control device 7th is connected to a negative pole of the fourth battery cell BT4 the series connection of all battery cells BT1 , ..., BT4 tied together.

A control and evaluation device is also shown 3 , the switching operations of the changeover switching elements WS1 , WS2 can control. It is possible that the control devices 3 , 7th are designed as a separate or as a common control device.

It is also shown that the positive pole of the first battery cell BT1 via a first protective line SL1 with the first connection line BL1 and a second protective line SL2 with the other connecting line BL2 connected is. In the first protective line SL1 is a first protection diode SD1 arranged, the forward direction of this first protective diode SD1 from the first connection line BL1 is oriented to the positive pole. In the second protective line SL2 is a second protection diode SD2 arranged, whose direction of passage from the second connecting line to the positive pole of the first battery cell BT1 is oriented.

It is also shown that the negative pole of the fourth and thus last battery cell BT4 via a third protective line SL3 with the first connection line BL1 is connected, being in the third protective line SL3 a third protective diode SD3 is arranged, the forward direction of which is from the negative pole to the first connecting line BL1 is oriented. Correspondingly, there is a fourth protective line SL4 a fourth protection diode SD4 arranged, whose forward direction from the negative pole to the second connecting line BL2 is oriented.

5 shows schematic time curves of a voltage UC over a capacitive element C. (see e.g. 2 ) in the transfer branch 2 and a charge reversal IL corresponding to a first operating mode of the reloading device 1 .

At a first point in time t0 at which the voltage UC above the capacitive element C. of the transshipment branch 2 , which is referred to below as the capacitor voltage, is zero or is less than a predetermined amount higher than 0 V, a first subsection of the in 2 shown series connection of all battery cells BT1, ...., BT4 with the connecting lines BL1 , BL2 connected, in particular by controlling the corresponding switching elements S1 , ..., S5 . For example, the first battery cell BT1 , which in this exemplary embodiment forms the first section by way of example, by closing the first and second switching elements S1 , S2 with the connecting lines BL1 , BL2 get connected. It is continued by activating the changeover switching elements WS1 , WS2 a short circuit of the first battery cell BT1 via the inductive connecting elements VL1 , VL2 manufactured. This can be done by using the first changeover switching element WS1 with the further connection A2 of the transshipment branch 2 and also the further changeover switching element WS2 with the second connection A2 of the transhipment branch is connected.

Are the changeover switching elements WS1 , WS2 for example as in the in 3 Formed embodiment shown, this can be done, for example, by switching the second MOSFET on M2 and the fourth MOSFET M4 in the in 3 shown embodiment take place.

After the first point in time t0, the charge reversal increases IL essentially linear. At a second point in time t1 the short circuit is canceled, in particular by, for example, the further changeover switch WS2 no longer with the further connection A2 of the transshipment branch 2 connected is. For example, the fourth MOSFET can do this M4 the in 3 shown embodiment are switched blocking. Is the voltage across the first battery cell BT1 greater than the voltage across the recharging capacitor C. , the current flow commutates in the free-wheeling diode of the in 3 MOSFETs shown M3 .

It is also possible at the second time t1 the first connection A1 of the transshipment branch 2 via the first changeover switching element WS1 with the first connection line BL1 to be connected, for example by switching the in 3 third MOSFETs shown M3 .

The recharging current IL continues to rise until the voltage on the recharge capacitor UC the voltage of the first battery cell BT1 achieved. Then the inductive connecting elements VL1 , VL2 the recharging current IL driven further and charges the recharging capacitor UC further on. It is shown that the charge-reversal capacitor UC at a third point in time t2 roughly twice the cell voltage, i.e. a voltage that is twice as high as the voltage across the first battery cell BT1 is reached. Became the second date t1 the third MOSFET M3 switched on, it will be switched on by the third point in time at the latest t2 switched to blocking. At the third point in time t2 becomes the recharging current IL to zero.

Between the third point in time t2 and a fourth point in time t3 no recharging current flows IL . During this period, the connection lines BL1 , BL2 connected first battery cell BT1 from these connecting lines BL1 , BL2 are separated, in which case the battery cell to be charged, for example the second battery cell BT2 , which exemplifies the further subsection of the series connection of all battery cells BT1, ...., BT4 forms, by controlling the corresponding switching elements S2 , S3 with the connecting lines BL1 , BL2 is connected.

At the fourth point in time t3 becomes the transfer branch 2 with the connecting lines BL1 , BL2 connected, in particular by the first port A1 via the further changeover switching element WS2 with the second connection line BL2 and the further connection A2 via the first changeover switching element WS1 with the first connection line BL1 is connected. The recharging current now flows IL in the negative direction via the inductive connecting elements VL1 , VL2 from the recharging capacitor UC into the second battery cell BT2 until the voltage of the recharging capacitor UC on the cell voltage of this second battery cell BT2 has decreased. Thereafter, the charge current IL due to the inductive connection elements VL1 , VL2 driven on and charges the second battery cell BT2 further on. Are the changeover switching elements WS1 , WS2 formed by half branches of a bridge circuit, as in 3 shown, for example, the third MOSFET M3 as well as the second MOSFET M2 after the fourth point in time t3 be switched blocking, the charge reversal IL can continue to flow through the corresponding freewheeling diodes.

At a fifth point in time t4 becomes the recharging current IL to zero, in which case the second battery cell to be charged BT2 by opening the corresponding switching elements S2 , S3 from the connecting lines BL1 , BL2 separated so that the recharge capacitor C. not from this battery cell BT2 is loaded.

6th shows schematic time curves of a voltage UC over a capacitive element C. (see e.g. 2 ) in the transfer branch 2 and a charge reversal IL corresponding to a further operating mode of the reloading device 1 .

At a first point in time t0 at which the voltage UC above the capacitive element C. of the transshipment branch 2 , which is referred to below as the capacitor voltage, is greater than the voltage of a first section of the in 2 shown series connection of all battery cells BT1, ...., BT4 is, this is with the connecting lines BL1 , BL2 connected, in particular by controlling the corresponding switching elements S1 , ..., S5 . For example, the first battery cell BT1 , which in this exemplary embodiment forms the first section by way of example, by closing the first and second switching elements S1 , S2 with the connecting lines BL1 , BL2 are connected, with then the voltage across the recharging capacitor C. greater than the voltage across the first battery cell BT1 is. It is continued by activating the changeover switching elements WS1 , WS2 a short circuit of the first battery cell BT1 via the inductive connecting elements VL1 , VL2 manufactured. This can be done by using the first changeover switching element WS1 with the further connection A2 of the transshipment branch 2 and also the further changeover switching element WS2 with the second connection A2 of the transhipment branch is connected.

Are the changeover switching elements WS1 , WS2 for example as in the in 3 Formed embodiment shown, this can be done, for example, by switching the second MOSFET on M2 and the fourth MOSFET M4 in the in 3 shown embodiment take place.

After the first point in time t0, the charge reversal increases IL essentially linear. At a second point in time t1 the short circuit is canceled, in particular by, for example, the further changeover switch WS2 no longer with the further connection A2 of the transshipment branch 2 connected is. For example, the fourth MOSFET can do this M4 the in 3 shown embodiment are switched blocking.

It is also possible at the second time t1 the first connection A1 of the transshipment branch 2 via the first changeover switching element WS1 with the first connection line BL1 to be connected, for example by switching the in 3 third MOSFETs shown M3 .

The recharging current IL decreases, but is due to the inductive connecting elements VL1 , VL2 further into the recharging capacitor C. driven and charges this recharging capacitor UC further on. It is shown that the charge-reversal capacitor UC at a third point in time t2 reaches the highest tension. Became the second date t1 the third MOSFET M3 switched on, it will be switched on by the third point in time at the latest t2 switched to blocking. At the third point in time t2 he will recharge current IL to zero.

Between the third point in time t2 and a fourth point in time t3 no recharging current flows IL , where the voltage across the recharge capacitor C. remains constant. During this period, the connection lines BL1 , BL2 connected first battery cell BT1 from these connecting lines BL1 , BL2 are separated, in which case the battery cell to be charged, for example the second battery cell BT2 , which exemplifies the further subsection of the series connection of all battery cells BT1, ...., BT4 forms, by controlling the corresponding switching elements S2 , S3 with the connecting lines BL1 , BL2 is connected.

At the fourth point in time t3 becomes the transfer branch 2 with the connecting lines BL1 , BL2 connected, in particular by the first port A1 via the further changeover switching element WS2 with the second connection line BL2 and the further connection A2 via the first changeover switching element WS1 with the first connection line BL1 is connected. The recharging current now flows IL in the negative direction via the inductive connecting elements VL1 , VL2 from the recharging capacitor UC into the second battery cell BT2 .

The charge current is temporarily here IL due to the inductive connection elements VL1 , VL2 driven on and charges the second battery cell BT2 further on. Are the changeover switching elements WS1 , WS2 formed by half branches of a bridge circuit, as in 3 shown, for example, the third MOSFET M3 as well as the second MOSFET M2 after the fourth point in time t3 , especially at a fifth point in time t4 , be switched off, whereby the charge reversal IL can continue to flow through the corresponding freewheeling diodes.

At a sixth point in time t5 becomes the recharging current IL to zero, then the electrical energy of the inductive connecting elements VL1 , VL2 into the second battery cell BT2 has discharged. There is no further disconnection of the second battery cell BT2 from the connecting lines VL1 , VL2 is necessary because the MOSFET used free-wheeling diodes M1 , M2 , M3 , M4 in the half branches of the in 3 illustrated embodiment a further current flow and thus a renewed discharge of the second battery cell BT2 impede.

List of reference symbols

1

Reloading device

2

Transshipment branch

3

Control and evaluation device

7th

Control device

C.

capacitor

L.

Kitchen sink

R.

Resistance element

S1, ..., S12

Switching element

BT1, ..., BT12

Battery cell

BL1

first connection line

BL2

second connection line

A1

first connection

A2

second connection

IL

Recharge current

UC

Capacitor voltage

UL

Coil voltage

M1, ..., M4

MOSFET

VL1, VL2

inductive connector

WS1, WS2

Changeover switching element

SL1, ..., SL4

Protective line

SD1, ..., SD4

Protection diodes

CS1, ..., CS5

Control signal lines

t1, ..., t5

Points in time

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 10446880 B2 [0002]
• DE 102010029015 A1 [0003]
• US 10396569 B2 [0004]
• DE 102018221099 [0005, 0090, 0104]

Claims (10)

Charging device for a battery, the battery comprising a series connection of at least two battery cells (BT1, ..., BT12), with a positive pole of each odd battery cell (BT1, BT3, ..., BT11) and a negative pole of each even battery cell (BT2 , BT4, ..., BT12) the series connection of all battery cells (BT1, ..., BT12) or a first subset of these battery cells (BT1, ..., BT12) via a switching element (S1, ..., S12) a first connecting line (BL1) can be connected, a plus pole of each even battery cell (BT2, BT4, ..., BT12) and a minus pole of each odd battery cell (BT1, BT3, ..., BT11) of the series connection of all battery cells (BT1, ..., BT12) or the first subset of these battery cells (BT1, ..., BT12) can be connected to a further connecting line (BL2) via a switching element (S1, ..., S12), the recharging device (1) at least comprises a first transfer branch (2) with at least one capacitive element, characterized in that the first connecting line (BL1) can be connected via a first changeover switching element (WS1) to a first connection (A1) as well as to a further connection (A2) of the transfer branch (2), the further connection line (BL2) being connectable via a further changeover switching element (WS2) can be connected to the first connection (A1) as well as to the further connection (A2) of the transfer branch (2), a connection line-side connection of the first changeover switching element (WS1) via a first inductive connection element (VL1) to the first connection line (BL1) and / or a connection line-side connection of the further changeover switching element (WS2) is connected to the further connection line (BL2) via a further inductive connection element (VL2). Reloading device according to Claim 1 , characterized in that a connection line-side connection of the first changeover switching element (WS1) via a first inductive connection element (VL1) with the first connection line (BL1) and a connection line-side connection of the further changeover switching element (WS2) via a further inductive connection element (VL2) with the other Connecting line (BL2) is connected, the inductive connecting elements (VL1, VL2) having the same inductance. Transfer device according to one of the preceding claims, characterized in that a changeover switching element (WS1, WS2) is designed as a series connection of two transistor switches (M1, M2, M3, M4) or comprises such a series connection. Reloading device according to Claim 3 , characterized in that the changeover switching elements (WS1, WS2) are each designed as half-branches of a bridge circuit or comprise these half-branches. Transfer device according to one of the preceding claims, characterized in that the capacitive element of the transfer branch (2) is designed as a polarized capacitor or comprises one. Method for operating a reloading device (1) according to one of the Claims 1 until 5 , characterized in that in a discharged state a first section of the series connection of all battery cells (BT1, ..., BT12) is connected to the transfer branch (2), with a further section of the series connection of all battery cells (BT1, ...) in a charge state. , BT12) is connected to the transfer branch (2), at least one battery cell (BT1, ..., BT12) of the first subsection not being part of the further subsection. Procedure according to Claim 6 , characterized in that the discharge state is set when a voltage across the capacitive element of the transfer branch (2) is less than the voltage across the first section of the series connection of all battery cells (BT1, ..., BT12). Procedure according to Claim 6 , characterized in that the discharge state is set when a voltage across the capacitive element of the transfer branch (2) is greater than the voltage across the first section of the series connection of all battery cells (BT1, ..., BT12). Method according to one of the Claims 6 until 8th , characterized in that a recharging current is detected and switching times for switching the changeover switches (WS1, WS2) and / or switching times for switching the switching elements (S1, ..., S12) are determined as a function of the current. Method according to one of the Claims 6 until 8th , characterized in that a temporal course of the recharging current is determined as a function of the electrical properties of the elements of the recharging device (1) and switching times for switching the changeover switches (WS1, WS2) and / or switching times for switching the switching elements (S1, ..., S12) can be determined as a function of the current.

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