DE102018221099A1 - Transfer device, method for operating a transfer device and vehicle - Google Patents

Abstract

The invention relates to a recharging device (1) for a battery, the battery comprising a series connection of at least two battery cells (BT1, ..., BT24), a positive pole of each odd battery cell (BT1, BT3, ..., BT23) and a negative pole of each straight battery cell (BT2, BT4, ..., BT24) of the series connection of all battery cells (BT1, ..., BT24) or a first subset of these battery cells (BT1, ..., BT24) via a switching element (S1, ..., S25) can be connected to a first connecting line (BL1), with a positive pole of each even battery cell (BT2, BT4, ..., BT24) and a negative pole of each odd battery cell (BT1, BT3, ..., BT23) the series connection of all battery cells (BT1, ..., BT24) or the first subset of these battery cells (BT1, ..., BT24) can be connected to a further connecting line (BL2) via a switching element (S1, ..., S25), wherein the transfer device (1) comprises at least a first transfer branch (2), a first connection (A1) of the transfer branch (2) can be connected or connected to the first connecting line (BL1), a further connection (A2) of the transfer branch (2) being connectable or connected to the further connecting line (BL2), the transfer branch (2) having a series connection of at least comprises a capacitive element and at least one inductive element, as well as a method for operating a transfer device and a vehicle with a battery and a transfer device (1).

Description

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

The DE 10 2005 045 107 A1 discloses a charging method for extending the life of batteries and an apparatus for performing the same.

The DE 10 2017 037 094 A1 discloses a charge balancing circuit for a plurality of battery cells connected in series and a method for predictive control of the charge balancing between such battery cells.

The document M. Daowd et al. "A review of passive and active battery balancing based on Matlab / Simuling", International Review of Electrical Engineering, Copyright 2011. This discloses different circuit topologies for a so-called passive and active balancing of charge states of different battery cells of a battery.

Methods for so-called active charge equalization and methods for so-called passive charge equalization are known.

The passive balancing of charge states disadvantageously generates an undesirably high thermal energy, in particular since an excessively high charge state is reduced via a current flow via a resistor. The usable capacity is also reduced by the thermal energy, in particular by the amount of thermal energy.

The circuit topologies of so-called active compensation circuits generally include a large number of switching elements in order to produce current paths required for compensation or to separate current paths that are not required. It is desirable to reduce the number of switching elements required.

It is also known that high currents can occur during active charge equalization, which can be disadvantageous for the operability of the transfer device.

The technical problem therefore arises of creating a transfer device for a battery, a method for operating such a transfer device and a vehicle with such a transfer device, which achieve an improved guarantee of the operability of the transfer device. The problem also arises of creating an inexpensive transfer device, in particular with a minimized number of switching elements, and of reducing the thermal energy generated during charge equalization.

The solution to the technical problem results from the subjects with the features of independent claims 1, 8 and 16. Further advantageous refinements of the invention result from the subclaims.

A recharging 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 comprise 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 the operation of an electrical machine for driving 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 denotes a battery cell with an odd atomic number, the atomic number denoting the placement of the battery cell in the order of the battery cells connected in series. In other words, the atomic number serves to identify the position at which the battery cell is located within the row of battery cells connected in series. An odd battery cell is e.g. that is, the first battery cell of the series circuit, the third battery cell of the series circuit, the fifth battery cell of the series circuit, etc. Accordingly, a straight battery cell denotes a battery cell with an even atomic number. A straight battery cell is e.g. the second battery cell of the series circuit, the fourth battery cell of the series circuit, the sixth battery cell of the series circuit, etc.

It is possible that each positive pole of each odd battery cell and each negative pole of each even battery cell can be connected 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, these poles can be connectable to the first connecting line via a common switching element.

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

It is possible that all positive poles of each even battery cell and all negative poles of each odd battery cell can be connected to the further connecting line via switching elements which are formed separately from one another. However, if a negative pole of an odd battery cell is connected to a positive pole of an even battery cell, these poles can be connectable to the further connecting line via a common switching element.

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

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

The recharging device in this case comprises the switching elements explained for connecting the poles of the battery cells to the corresponding connecting lines. A switching element can in particular be designed as an electronic switching element, in particular as a MOSFET or as an IGBT. The device also includes the connection lines explained.

The transfer device further comprises at least one first transfer branch, which can also be referred to as a first transfer section. In this case, a first connection of the recharging branch can be connected or connected to the first connecting line, in particular via exactly or at least one switching element, in particular permanently connected. Furthermore, a further connection of the transfer branch can be connected to the further connecting line, in particular via exactly one or at least one 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 designed here as connecting lines that are different from one another.

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

It is possible that the first connection can be connected both to the first connection line and to the further connection line, in particular by means of a switching element, for example 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 which 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 explained in more detail below, however, it is also possible, in particular, for the first connection to be connectable to the first connecting line but not to the further connecting line. In other words This can mean that the recharging device is configured such 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 connecting line and to the further connecting line, in particular by means of a switching element, e.g. by means of a two-way 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 which 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 explained in more detail below, however, it is also possible, in particular, for the further connection to be connectable to the further connecting line, but not to the first connecting line. In other words, this can mean that the recharging device is configured such that no electrical connection can be established between the first connection and the further connecting line.

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

The transfer branch is preferably formed by such a series connection. In this case, the transfer branch only includes the series connection explained.

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 discharge process and a charging process.

So it is e.g. possible to transport charge from one or more battery cell (s) 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 recharging branch into one or more battery cells, in particular likewise via a corresponding current flow. In this case, a battery cell from which electrical energy is transported in the discharge process into the capacitive element of the transfer branch is preferably not part of the battery cells into which electrical energy / charge is transported from the capacitive element of the charge branch during the charging process. Preferably, all the battery cells from which electrical energy / charge is transported in the discharge process into the capacitive element of the transfer branch are different from the battery cells into which electrical energy / charge is transported from the capacitive element of the transfer branch in the charge process.

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

The transfer device can of course include 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 transfer 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. Using the evaluation device, variables explained in more detail below can be evaluated.

In a further embodiment, the recharging branch comprises a series connection of at least one capacitive element, at least one inductive element and at least one resistive element. The resistive element can in particular be designed as a resistor. However, it is also possible that the transfer branch does not comprise or contain a resistive element. The transfer branch is preferably formed by the series connection explained.

This advantageously results in that the vibration properties of the resonant circuit formed by the transfer branch can be adapted. In particular, the provision of a resistor makes it possible to set a damping of such a resonant circuit and thus of desired electrical properties of the resonant circuit and thus of the transfer device.

In a further embodiment, the elements of the series circuit form an undamped resonant circuit in the transfer branch. The formation of an undamped resonant circuit advantageously reduces ohmic losses during a recharging process. As a result, less thermal energy is transferred to a control board and there are also fewer losses in components of control electronics, which can therefore also be designed in accordance with correspondingly lower requirements. Furthermore, there is advantageously a high degree of efficiency in charge balancing, the efficiency being the ratio between the charge removed from the battery cell (s) of the first section during the discharge process and the charge supplied to the battery cell (s) of the further section during the charging process becomes.

It is also possible for the elements of the series connection in the transfer branch to form an undamped resonant circuit. An undamped oscillating circuit here designates an oscillating circuit in which state variables, in particular an electrical current and an electrical voltage, carry out several oscillation processes at connections of the oscillating circuit, that is to say they undergo several oscillation periods, an amplitude of the oscillations decreasing quantitatively over time and approaching a final value. This advantageously results in a good compromise between a sufficiently high efficiency in charge balancing and ohmic losses.

Alternatively, the elements of the series connection form a damped resonant circuit in the recharging branch, which can also be referred to as a damped resonant circuit. A damped oscillating circuit here designates an oscillating circuit in which state variables, in particular an electrical current and an electrical voltage at connections of the oscillating circuit, execute exactly one oscillation or exactly one half oscillation and then approach a final value without further oscillations.

This advantageously results in the fact that no computationally intensive evaluation is necessary to determine a switching point in time to terminate a state of charge, since in the case of a damped oscillating circuit, a current through the recharging branch does not have a zero crossing and thus does not undesirably have current in the state of charge in the capacitive element of the recharging branch flows back. Rather, the switching time for ending the state of charge can be a predetermined time after the switching time for setting the state of charge.

In a further embodiment, the first connection of the transfer branch cannot be connected to the further connecting line and the further connection of the transfer branch cannot be connected to the first connecting line. This has already been explained above. In particular, it is possible for the first connection to be permanently connected to the first connection line or to be connectable to it, and for the transfer device not to include any means for establishing an electrical connection between the first connection and the further connection line. Furthermore, it is conceivable that the further connection is permanently connected to the further connection line or can be connected to it, and the transfer device does not include any means for establishing an electrical connection between the further connection and the first connection line. In other words, there can be no direct electrical connection between the first connection and the further connection line and between the further connection and the first connection line. Of course, however, it is possible to establish such an electrical connection via at least one electrical or electronic component, in particular via a battery cell or a series connection of at least two battery cells.

This advantageously results in a reduction in the number of switching elements in the proposed transfer device, which is used for active charge equalization. In particular, no switching elements are required to connect the first connection to the further connecting line and to connect the further connection to the first connecting line. This in turn advantageously enables the saving of manufacturing costs and the saving of installation space in the manufacture of the transfer device.

Computational effort to control the switching elements is also advantageously reduced. This, in turn, enables the use of computation devices which perform less than a transfer device with more switching elements, and further cost savings.

In a further embodiment, the battery comprises a series connection of at least four battery cells. The battery cell preferably comprises a series connection of exactly nine or more than nine battery cells. The corresponding advantages are explained in more detail below.

In a further embodiment, the transfer device comprises a further transfer 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 for the further transfer branch to comprise 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 series connections mentioned. 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 connecting line, in particular via a switching element, or 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 connected, in particular permanently connected.

The third and fourth connecting lines are designed as different connecting lines. 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 connecting line, it may be possible that the first connection of the further transfer branch cannot be connected to the fourth connecting line. Likewise, the further connection of the further transfer branch cannot be connectable to the third connecting line. Also, these connections cannot be connectable to the first and second connecting lines.

Furthermore, a positive pole of each odd battery cell and a negative pole of each even battery cell 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 battery cells of the battery connected in series. Here, however, the further subset of battery cells comprises at least one battery cell that is not part of the first subset of battery cells explained above.

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

Furthermore, a positive pole of each even battery cell and a negative pole of each 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 each even battery cell and a negative pole of each odd battery cell of the further battery can be connected to the fourth connecting line via a switching element.

This advantageously results in that a charge equalization can take place over several capacitive elements. This in turn advantageously increases the flexibility of the recharging and the possibility of using switching elements with a lower maximum dielectric strength. This in turn saves costs in the manufacture of the transfer device. Furthermore, it advantageously results that a recharge between battery cells of different batteries can also take place.

In a further embodiment, the recharging device comprises at least one means for detecting or determining a voltage across the capacitive element of a recharging branch and at least one means for detecting or determining a voltage across the inductive element of a recharging 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 those skilled in the art can be used to detect or determine such a voltage. The means for detection or determination can be connected in terms of data and / or signal technology to the previously explained evaluation device. This advantageously results in an improved control of switching elements of the recharging device being made possible, namely control depending on the detected or determined voltage. This is explained in more detail below.

A method for operating a transfer device according to one of the embodiments described in this disclosure is also proposed. In this case, a discharge state can be set, wherein in the discharge state a first section of the series connection of all battery cells is connected to the recharging branch. In this discharge state, electrical energy / charge can be transported from the battery cell (s) into the at least one capacitive element of the recharging branch. This can also be called an unloading process. The discharge state can be set, for example, by controlling corresponding switching elements. In the discharge state, in particular at least one battery cell of the first section can be discharged.

The first section of the series connection of all battery cells comprises at least one, but preferably several, series-connected battery cell (s) of the series connection of all battery cells, but further preferably not all battery cells of the series connection. However, it is also possible for the first section to comprise exactly one battery cell.

In a charge state, a further section of the series connection of all battery cells is connected to the recharging branch. The further subsection of battery cells in this case comprises at least one, but preferably several, battery cells connected in series of the series connection of all battery cells. However, it is also possible for the further subsection to comprise exactly one battery cell.

The first section preferably comprises more battery cells than the further section. This advantageously results in a faster charge equalization.

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

The discharge and charge state can be set by the control device explained above. In particular, the discharge state can be set until the at least one capacitive element of the recharging 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 cells in the first section have a predetermined state of charge has reached, in particular until the state of charge of this battery cell (s) has dropped to the predetermined state of charge.

The state of charge can be set until one or more battery cells of the further section 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 the at least one capacitive element has reached a predetermined threshold, in particular until this state of charge has dropped to the predetermined threshold.

In this case, the transfer device can 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 "discharge state, state of charge" or "discharge state, idle state, state of charge" can be repeated periodically. In the corresponding states of the different periods, different battery cells can be discharged or charged. It is e.g. possible that one of the odd battery cells is charged in the charging states of successive periods. After all the odd battery cells have been charged, one of the even battery cells can then be charged in the charging states of further periods in time. The capacitor in the recharging branch can be recharged between the period sequence for charging the odd battery cells and the period sequence for charging the even battery cells, which will be explained below.

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

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

In a preferred embodiment, the first section comprises more battery cells than the further section. The difference between the number of battery cells of the first section and the number of battery cells of the further section is preferably greater than two. This advantageously results in a short period of time for charge equalization. Furthermore, it advantageously results that a capacitive element with low capacitance, in particular in the μF range, can be used, which in turn reduces the manufacturing costs of the recharging circuit.

More preferably, the first section comprises an odd number of battery cells. More preferably, the further section also includes an odd number of battery cells.

In a further embodiment, the first section comprises at least three, in particular exactly three, battery cells. In this embodiment, the further subsection can comprise exactly one battery cell. This advantageously results in high efficiency. In particular, the maximum possible efficiency results if exactly one battery cell is to be charged, that is to say if the further subsection comprises exactly one battery cell, wherein a rapid charge equalization is made possible.

In a further embodiment, a switching point in time for establishing or disconnecting a section of the series connection, that is to say the first or the further section, with the transfer branch is selected such that an amplitude of the current which flows through the transfer branch at this point in time and also as a current can be designated by the transfer branch, is zero or does not deviate more than a predetermined measure from zero. The point in time at which the amplitude of the current through the recharging branch is zero or no longer deviates from zero as a predetermined measure can also be referred to as the zero current instant. This point in time can therefore in particular be a point in time for setting or ending the charge state or for setting or ending the discharge state. In particular, the point in time is a point in time for ending the charge state.

This advantageously results in a high efficiency of charge balancing, a further improvement in the guarantee of operability and a reduction in switching losses.

In this regard, it should be noted that in the case of a recharging branch formed by an undamped oscillating circuit, the current through the recharging branch, in particular in the discharge state, can have a zero crossing and thus a change of sign. Current can thus flow back from the battery cells into the capacitive element, as a result of which these battery cells are discharged again and the efficiency of the charge equalization is thus reduced. With a damped resonant circuit, no zero crossing can occur. In this case, however, the switching point in time can be selected as a point in time at which the current through the recharging branch no longer deviates from a predetermined value from zero.

The recharging device can further comprise a means for detecting or determining a current flowing through the recharging branch. Furthermore, the recharging device can comprise a means for predicting a point in time of the zero crossing of this current. This means can be formed, for example, by the evaluation or control device. It is conceivable, for example, that at least one current value or a time profile of current values of the current is detected or determined by the recharging branch, with a (future) point in time being then determined (predicted) depending on the current value or the time profile of the current values the amplitude of the current through the recharging branch is zero or does not deviate more than a predetermined amount from zero. A switching time of switching elements for establishing or disconnecting the connection explained can then be selected as this time.

In a further embodiment, a voltage across the at least one capacitive element and a voltage across the at least one inductive element of the transfer branch are determined or detected. Furthermore, a zero difference time is determined at which the voltage across the at least one capacitive element does not deviate from the voltage across the at least one inductive element, or does not deviate by more than a predetermined amount. For example, the point in time at which the voltage across the at least one capacitive element exceeds the voltage across the at least one inductive element for the first time after a reference point in time to be explained in more detail below can be determined.

Furthermore, a switching time for establishing or disconnecting a connection of a section, that is to say the first or the further section, of the series connection with the recharging branch is determined as a function of the zero difference time. In particular, it can be assumed that the previously explained point in time, in which the amplitude of the current through the transfer branch becomes zero or does not deviate more than a predetermined amount from zero, is related, in particular functionally, to the explained zero difference time. For example, the zero current instant can be after the zero difference instant by a predetermined period of time. In such a case, the functional relationship can be formed by a sum function, by means of which a predetermined time period is added to the zero difference time in order to determine the zero current time.

This advantageously results in a simple and reliable determination of the zero current instant explained above, which in turn can reduce switching losses in a simple manner and improve the operability.

In a further embodiment, a time period between the zero difference time and a reference time point is determined, the switching time point being determined such that a time period between the switching time point and the reference time point corresponds to three times the time period between the zero difference time point and the reference time point. This determination is preferably made when the resonant circuit formed by the transfer branch is a damped resonant circuit.

The time between the switching time and the reference time can also be longer than 2.5 times, 2.8 times or 2.9 times the time between the zero difference time and the reference time. Alternatively or cumulatively, the time period between the switching time and the reference time can be shorter than 3 times the time period between the zero difference time and the reference time. This determination is preferably made when the resonant circuit formed by the recharging branch is an undamped resonant circuit in order to prevent energy from being transferred back into the recharging branch, in particular in a charge state.

If the resonant circuit formed by the transfer branch is a damped resonant circuit, the time period between the switching time and the reference time can be longer than 3 times the time period between the zero difference time and the reference time.

The reference point in time can in particular be selected as the point in time at which the recharging branch last became part of a closed circuit, that is to say was switched on. For example, the reference point in time can be selected as the point in time of the last switching operation to establish a connection of a section of the series connection to the transfer branch.

Simulations and tests have shown that this enables a sufficiently accurate and easy-to-implement prediction of the zero-current instant and thus the switching instant for manufacture or disconnection.

In a further embodiment, the at least one capacitive element of the recharging branch is connected to at least one battery cell, preferably to a plurality of battery cells connected in series, in such a way that the capacitive element is recharged. In particular, a change in polarization of the state of charge of the capacitive element can take place. A polarization change can take place in that a voltage changes its sign between a first connection of the capacitive element and a further connection of the capacitive element. This can mean that a sign of the state of charge of the at least one capacitive element is changed during the recharging process. It is possible, but not imperative, that a sign, but not an amount of the state of charge, is changed when the polarity is changed. The state of charge can be set here, for example by activating corresponding switching elements.

To charge the capacitive element, a series connection of several battery cells or exactly one battery cell with the polarity to be set, preferably the battery cell with the highest cell voltage, can be connected to the capacitive element.

This advantageously results in the fact that both even and odd battery cells of the series circuit can be integrated into a charge equalization. Despite a small number of switching elements, this ensures that the state of charge can be compensated for by a large number of battery cells. In particular, in comparison with a transfer device with two switching element levels, which will be explained in more detail below, there is a reduction in the switching elements required.

Likewise, there is an advantageous protection of components when carrying out the charge equalization for both even and odd battery cells.

In a further embodiment, a first partial section of the series connection of all battery cells is connected to a further recharging branch in a further discharge state.

Further alternatively or cumulatively, a partial section of the series connection of all battery cells is connected to the further recharging branch in a further charge state.

It is further possible that in the further discharge state a series connection of all battery cells or a partial section of this series connection or also only one battery cell of a further battery is connected to the further recharging branch. Further alternatively or cumulatively, it is possible that in the further state of charge the further recharging branch is connected to the series connection of all battery cells or a partial section of this series connection or a battery cell of the further battery.

Here, the statements regarding the charging and discharging process via the first transfer branch also apply accordingly to the charging and discharging process via the further transfer branch.

This advantageously enables the charge to be balanced between battery cells of different batteries. Furthermore, it is advantageously made possible for a charge equalization to take place in addition or as an alternative to the capacitive element of a transfer branch, also via the capacitive element of a further transfer branch, as a result of which larger ones Amounts of cargo can be transported during charge balancing.

A vehicle, in particular a motor vehicle, is further 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.

• 1 ein schematisches Schaltbild einer erfindungsgemäßen Umladevorrichtung gemäß einer ersten Ausführungsform,
• 2a eine erfindungsgemäße Umladevorrichtung in einem Leerlaufzustand,
• 2b die in 2a dargestellte Umladevorrichtung in einem Entladezustand,
• 2c die in 2a dargestellte Umladevorrichtung in einem Ladezustand,
• 3a schematische zeitliche Verläufe von Spannungen und einem Strom in einem Umladezweig mit einem ungedämpften Resonanzschwingkreis,
• 3b ein schematischer zeitlicher Verlauf von Spannungen und einem Strom in dem Umladezweig mit einem unterdämpften Resonanzschwingkreis,
• 3c schematische zeitliche Verläufe von Spannungen und einem Strom im Umladezweig mit einem bedämpften Resonanzschwingkreis,
• 4 ein schematisches Schaltbild einer Umladevorrichtung gemäß einer weiteren Ausführungsform und
• 5 ein schematisches Schaltbild einer erfindungsgemäßen Umladevorrichtung gemäß einer weiteren Ausführungsform.

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

• 1 1 shows a schematic circuit diagram of a transfer device according to the invention in accordance with a first embodiment,
• 2a a transfer device according to the invention in an idle state,
• 2 B in the 2a Reloading device shown in a discharge state,
• 2c in the 2a shown transfer device in a state of charge,
• 3a schematic temporal profiles of voltages and a current in a transfer branch with an undamped resonant circuit,
• 3b 2 shows a schematic time course of voltages and a current in the transfer branch with an undamped resonant circuit,
• 3c schematic temporal courses of voltages and a current in the transfer branch with a damped resonant circuit,
• 4th a schematic diagram of a transfer device according to a further embodiment and
• 5 a schematic diagram of a transfer device according to the invention according to another embodiment.

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

1 shows a schematic circuit diagram of a transfer device according to the invention 1 for a battery, 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 negative poles of the battery cells BT1 , ..., BT12 represented with a "-" sign. Battery cell voltage is also shown U1 , U2 , U3 , U4 , ..., U11 , U12 , this battery cell voltage U1 , ..., U12 above the respective battery cell BT1 , ...., BT12 falls off.

This is 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 transfer device further comprises switching elements S1 , S2 , S3 , S4 , ..., S12 , S13 . In particular, the number of switching elements S1 , ..., S13 the transfer device 1 used to make or disconnect 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 make the number one greater than the number of battery cells connected in series BT1 , ..., BT12 the battery.

In 1 is shown to be a positive pole of every odd battery cell BT1 , BT3 , ..., BT11 via a switching element S1 , S3 , ... with the first connecting line BL1 is connectable. It is also shown that a negative pole of each straight battery cell of the series connection via a switching element S3 , ..., S13 with the first connecting line BL1 is connectable. Here are 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 each in the series connection BT2 , BT4 , ... electrically connected.

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

It is also shown that the transfer device 1 a transfer branch 2nd comprises, the transfer branch by a series connection of a resistance element R , a capacitor C. and a coil L is formed. The transhipment branch 2nd has a first connection A1 and a second connector A2 on. The first connection A1 is electrical with the first connection line BL1 connected, especially permanently. Next is the first connection A1 of the transfer branch 2nd not directly or immediately with the second connection line BL2 connectable. In particular, an electrical connection between the first connection A1 of Transhipment branch 2nd and the second connecting line BL2 only via at least one battery cell BT1 , ..., BT12 getting produced.

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

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

It is shown here that the transfer branch 2nd the resistance R includes. However, this is not mandatory. So it is also conceivable that the reloading branch 2nd by connecting the capacitor in series C. and the coil L is formed and no resistance element R includes.

A capacitor voltage is also shown UC that over the capacitor C. of the transfer branch 2nd drops, as well as a coil voltage UL that over the coil L falls off.

The series connection of the resistor R , the capacitor C. and the coil L form a resonant circuit, in particular a damped resonant circuit. Is not a resistance element R in the transhipment branch 2nd is present, so the series connection forms in the transfer branch 2nd an undamped resonant circuit.

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

2a shows a transfer device 1 with six battery cells connected in series BT1 , ..., BT6 and seven switching elements S1 , ..., S7 . In 2a is shown that all switching elements S1 , ..., S7 are open. So none of the battery cells BT1 , .. ., BT6 with a first connection line BL1 or a second connection line BL2 connected. This state of the transfer device 1 can also be called an idle state.

In the exemplary embodiment explained, two switching elements, namely the third switching element, are in a discharge state S3 and the sixth switching element S6 , closed. This becomes a negative pole of the second battery cell BT2 and a positive pole of the third battery cell BT3 with the first connecting line BL1 connected. Next is a negative pole of the fifth battery cell BT5 and a positive pole of the sixth battery cell BT6 with the second connection line BL2 connected. Overall, a first section of the series connection of all battery cells is thus in the discharge state BT1 , ..., BT6 with the transfer branch 2nd connected, the first section being connected in series by the third battery cell BT3 , the fourth battery cell BT4 and the fifth battery cell BT5 is formed. In this discharge state, charge flows from this first section of the series circuit, that is from the third, fourth and fifth battery cells BT3 , BT4 , BT5 in the capacitor C. of the transfer branch 2nd , which can also be called unloading.

After a predetermined period of time or after reaching a predetermined target state of charge of the capacitor C. of the transfer branch 2nd or after reaching a predetermined minimum state of charge of a battery cell BT3 , BT4 , BT5 In the first section, all switching elements S1 , ..., S7 opened and the in 2a idle state shown set.

Then, in time after the discharge state and the idle state following the discharge state, the in 2c shown state of charge of the reloading device 1 set. For this purpose switching elements, namely in the present case the first and the second switching element S1 , S2 , closed. This becomes a positive pole of the first battery cell BT1 with the first connecting line BL1 and thus with the first connection point A1 connected. Next is a negative pole of the first battery cell BT1 with the second connection line BL2 and the second connection point A2 connected. In this discharge state, charge flows out of the capacitor C. into the first battery cell BT1 . This can also be called a charging process.

It is possible that the switching elements closed in the discharge state S1 , ..., S7 the transfer device 1 different from the switching elements closed in the state of charge S1 , ..., S7 the transfer device 1 differentiate. In particular, at least one switching element is closed in the discharge state S1 , ..., S7 the transfer device 1 not closed when charging. Furthermore, there are exactly two switching elements of the number of switching elements in both the charging and discharging state S1 , ..., S7 closed.

It should be noted that those in the 2a , 2 B and 2c shown states are purely exemplary. In particular, it is also possible for switching elements other than those shown S1 , ..., S7 be closed in the discharge or charge state.

From the 2a , 2 B and 2c it follows that the first section in the present exemplary embodiment has three battery cells BT3 , BT4 , BT5 comprises, the further section only one battery cell BT1 includes. Thus, the first section comprises more battery cells than the further section. Here, the first battery cell forms BT1 a further section of the series connection of all battery cells BT1 , ..., BT6 being the battery cell BT1 of the further section not part of the first section, that is, no battery cell BT3 , BT4 , BT5 of the first section.

3a shows a schematic time course of a capacitor voltage UC , a coil voltage UL and a stream 12 passing through the transhipment branch 2nd (please refer 1 ) flows, especially when a charge level is set. It is assumed that the transfer branch 2nd forms an undamped resonant circuit. In particular, the transfer branch comprises 2nd a series connection of a capacitor C. and a coil L , but the series connection is not a resistance element R includes.

It is shown that both the capacitor voltage UC who have favourited Coil Voltage UL as well as the current 12 in the transhipment branch 2nd have a periodic course over time.

Point of time T ₀ denotes a reference point in time. This reference point in time can in particular be the point in time at which the reloading device 1 last in a discharge state (see 2 B) or to a state of charge (see 2c ) was transferred.

A zero difference time is also shown T _ND , where at this zero difference time T _ND the capacitor voltage UC equal to the coil voltage UL is or does not deviate from it by more than a predetermined amount.

A zero current instant is also shown T _IN to which the stream 12 in the transfer branch or the amplitude of this current 12 Is zero or deviates no more than a predetermined amount from it.

A switching time for opening or closing switching elements is preferred S1 , ..., S13 the transfer device (see 1 ), in particular to terminate the state of charge and thus to set the idle state or a further state of discharge, selected such that it corresponds to such a zero-current instant.

In 3a it is shown that a time period from the reference time Z ₀ to the zero current time T _IN three times the time between the reference time T ₀ and the zero difference time T _ND corresponds. If the zero difference time T _ND determined, for example by determining / detecting and comparing the coil voltage UL and the capacitor voltage UC , the zero current instant T _IN and thus the switching time is also predicted, i.e. predicted. This can be done in particular through the 1 shown control and evaluation device 3rd respectively. For this purpose, this can be done with voltage sensors for detecting the capacitor and coil voltage UC , UL (not shown) connected.

3b shows a schematic of the capacitor voltage over time UC , the coil voltage UL and the stream 12 through the reloading branch 2nd (please refer 1 ). In the 3b Time profiles shown occur when the transfer branch forms an under-damped resonant circuit. Corresponding 3a is a zero difference time T _ND shown. Next is a zero current time T _IN shown. The reference time is also shown T ₀ . Also from the in 3b The temporal courses shown show that the time period between the reference time T ₀ and the zero difference time T _ND in about a third of the time between the reference time T ₀ and the zero current time T _IN corresponds.

Thus, it can also be used for a transfer branch designed as an undamped resonant circuit 2nd one according to the explanations 3a Prediction of the zero current instant T _IN and thus the switching time.

3c shows schematically temporal profiles of a capacitor voltage UC , a coil voltage UL and a stream 12 through the reloading branch 2nd (please refer 1 ), which occur when the of the transfer branch 2nd formed resonant circuit is a damped resonant circuit. It can be seen here that the current I2 in the transhipment branch 2nd never becomes zero. In this case, a switching time can be selected such that switching elements S1 , ..., S13 (please refer 1 ) be opened or closed when an amplitude of the current I2 in the transhipment branch 2nd is less than a predetermined threshold. Alternatively, the switching point in time can be selected such that a predetermined period of time between the reference point in time T ₀ and the switching time.

For each of the in 3a , 3b and 3c In the exemplary embodiments shown, the switching time should preferably be selected such that the switching process takes place or has ended before the current I2 in the transhipment branch 2nd flows in a direction that the current direction is opposite immediately before the start of the switching process. This can cause a backflow of current into the capacitor C. can be avoided, which in turn increases the efficiency of charge balancing.

4th shows a transfer device 1 according to a further embodiment of the invention. A battery is shown with a series connection of 24 battery cells BT1 , ..., BT24 as well as a first transfer branch 2nd and another transfer branch 4th . The further transfer branch 4th comprises a series connection of a capacitor C4 and a coil L4 the further transfer branch 4th . A capacitor voltage is also shown UC4 that over the capacitor C4 the further transfer branch 4th falls off. A first connection is also shown A14 and another connector A24 the further transfer branch 4th . The further transfer branch 4th is over the first connection A14 with a third connecting line BL3 and via the second connection A2 with a fourth connecting line BL4 connected, especially permanently.

The first transfer branch 2nd by a series connection of a capacitor C2 and a coil L2 of the first transfer branch 2nd is formed here via a first connection A1 with a first connection line BL1 and via a second connection A2 with a second connection line BL2 connected, especially permanently.

There are also positive poles of every odd battery cell BT1 , BT3 , ..., BT13 a first subset of the series connection of all battery cells BT1 , ..., BT24 via switching elements S1 , S3 , ..., S13 with the first connecting line BL1 connectable. There are also negative poles of each straight battery cell of the first subset via switching elements S3 , ..., S15 with the first connecting line BL1 connectable. The first subset of the series connection comprises all battery cells BT1 , ..., BT 24th the series connection from the first to the fourteenth battery cell BT1 , ..., BT14 . Furthermore, positive poles of each straight battery cell of this first subset are via switching elements S2 , S4 , ..., S14 with the second connection line BL2 connectable. There are also negative poles of every odd battery cell BT1 , BT3 , ..., BT13 this first subset via switching elements S2 , S4 , ..., S14 with the second connection line BL2 connectable.

Another subset of battery cells is also shown BT11 , ..., BT24 the series connection of all battery cells BT1 , ..., BT24 , this further subset the series connection of the eleventh battery cell BT11 up to the twenty-fourth battery cell BT24 includes.

It is also shown that each positive pole of the odd battery cells BT11 , BT13 , BT15 , BT17 , ..., BT23 this further subset via switching elements S11a , S13a , S15a , S17 , ..., S23 with the third connecting line BL3 are connectable. It is also shown that the negative poles of each straight battery cell BT12 , BT14 , BT16 , BT18 , ..., BT24 this further subset via switching elements S13a , S15a , S17 , ..., S25 with the third connecting line BL3 are connectable.

It is also shown that positive poles of each straight battery cell of the further subset via switching elements S12a , S14a , S16 , S18 , ..., S24 with the fourth connection line BL4 are connectable. It is also shown that minus poles of each odd battery cell of the further subset via switching elements S12a , S14a , S16 , S18 , ..., S24 with the fourth connection line BL4 are connectable.

Thus, a charge balance between battery cells BT1 , ..., BT24 both the capacitor C2 of the first transfer branch 2nd as well as the capacitor C4 the further transfer branch 4th be used. In particular, the battery cells BT11 , ..., BT14 the intersection between the first and the further subset both for a transport of charge / electrical energy between these battery cells BT11 , ..., BT14 and the capacitor C2 of the first transfer branch 2nd as well as the capacitor C4 the further transfer branch 4th be used. Thus, such a transport can either be between the capacitor C2 of the first transfer branch 2nd and the battery cells BT11 , ..., BT14 the intersection or between the capacitor C4 the further transfer branch 4th and these battery cells BT11 , ..., BT14 respectively.

This advantageously results in switching elements S1 , ..., S25 can be used with low maximum dielectric strengths.

5 shows a schematic circuit diagram of a transfer device 1 according to a further embodiment of the invention. A transfer branch is shown 2nd with a capacitor C. and a coil L connected in series. A first connection is also shown A1 and a second connector A2 of the transfer branch 2nd . Also shown is a series connection of four battery cells BT1 , BT2 , BT3 , BT4 . A first connecting line is also shown BL1 and a second connection line BL2 .

The plus 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 connecting line BL1 connectable. The minus poles of every straight battery cell BT2 , BT4 are via switching elements S3 , S5 with the first connecting line BL1 connectable. The plus 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 each odd battery cell are correspondingly BT1 , BT3 via switching elements S2 , S4 with the second connection line BL2 connectable.

It is also shown that the first connection A1 of the transfer branch 2nd via a switching element SA1 either with the first connecting line BL1 or with the second connecting line BL2 is connectable. This means that the first connection A1 via the switching element SA1 either with the first connecting line BL1 or with the second connecting line BL2 is connected or can be connected. It is also shown that the second connection A2 via a switching element SA2 either with the first connecting line BL1 or with the second connecting line BL2 is connected or can be connected. The switching elements SA1 , SA2 through which the connections A1 , A2 with the connecting lines BL1 , BL2 are connectable, are designed in particular as two-way switching elements. Here, the reloading device 1 be configured such that the second port A2 not with the first connection line BL1 can be connected when the first port A2 via the switching element SA1 with the first connecting line BL1 connected is. The second connection can continue A2 via the switching element SA2 not with the second connection line BL2 be connected when the first port A1 via the switching element SA1 with the second connection line BL2 connected is.

Here, the switching elements S1 , ..., S5 , over the poles of the battery cells BT1 , ..., BT4 with connecting lines BL1 , BL2 are connectable or via 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. The switching elements SA1 , SA2 , through which an electrical connection between the connections A1 , A2 of the transfer branch 2nd and the connecting lines BL1 , BL2 that can be produced or separated can be referred to as switching elements of a second switching element level.

Here, the in 5 Embodiment shown 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.

Reference symbol list

1

Reloading device

2nd

Transhipment branch

3rd

Control and evaluation device

4th

further transfer branch

C, C2, C4

capacitor

L, L2, L4

Kitchen sink

R

Resistance element

S1, ..., S25

Switching element

BT1, ..., BT24

Battery cell

BL1

first connection line

BL2

second connecting line

BL3

third connecting line

BL4

fourth connecting line

A1

first connection

A2

second connection

A14

first connection of the further transfer branch

A24

further connection of the further transfer branch

I2

Current through the transfer branch

UC

Capacitor voltage

UL

Coil tension

T ₀

Reference time

T _ND

Zero difference time

T _IN

Zero current time

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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

• DE 102005045107 A1 [0002]
• DE 102017037094 A1 [0003]

Claims (16)

Transfer device for a battery, the battery comprising a series connection of at least two battery cells (BT1, ..., BT24), with a positive pole of each odd battery cell (BT1, BT3, ..., BT23) and a negative pole of each even battery cell (BT2 , BT4, ..., BT24) of the series connection of all battery cells (BT1, ..., BT24) or a first subset of these battery cells (BT1, ..., BT24) with a switching element (S1, ..., S25) a first connecting line (BL1) can be connected, a positive pole of each even battery cell (BT2, BT4, ..., BT24) and a negative pole of each odd battery cell (BT1, BT3, ..., BT23) of the series connection of all battery cells (BT1, ..., BT24) or the first subset of these battery cells (BT1, ..., BT24) can be connected to a further connecting line (BL2) via a switching element (S1, ..., S25), the transfer device (1) at least comprises a first transfer branch (2), a first connection (A1) of the transfer branch (2) with the first connector Connection line (BL1) is connectable or connected, with a further connection (A2) of the transfer branch (2) being connectable or connected to the further connection line (BL2), characterized in that the transfer branch (2) is a series connection of at least one capacitive element and comprises at least one inductive element. Reloading device after Claim 1 , characterized in that the transfer branch (2) comprises a series connection of at least one capacitive element, at least one inductive element and at least one resistive element. Transfer device according to one of the preceding claims, characterized in that the elements of the series connection in the transfer branch (2) form an undamped or a damped resonant circuit. Transfer device according to one of the preceding claims, characterized in that the first connection (A1) of the transfer branch (2) cannot be connected to the further connecting line (BL2) and the further connection (A2) of the transfer branch cannot be connected to the first connecting line (BL1). Transfer device according to one of the preceding claims, characterized in that the battery comprises a series connection of at least four battery cells (BT1, ..., BT24). Transfer device according to one of the preceding claims, characterized in that the transfer device (2) comprises a further transfer branch (4), the further transfer branch (4) comprising a series connection of at least one capacitive element and at least one inductive element, a first connection ( A14) of the further transfer branch (4) can be connected or connected to a third connecting line (BL3), wherein a further connection (A24) of the further transfer branch (4) can be connected or connected to a fourth connecting line (BL4), one positive pole of each odd Battery cell (BT1, BT3, ..., BT23) and a negative pole of each straight battery cell (BT2, BT4, ..., BT24) of all battery cells (BT1, ..., BT24) or a further subset of these battery cells (BT1 ,. .., BT24) or battery cells of a further battery can be connected to the third connecting line (BL3) via a switching element (S11a, ..., S25), with one positive pole of each straight battery ie cell (BT2, BT4, ..., BT24) and a negative pole of each odd battery cell (BT1, BT3, ..., BT23) of all battery cells (BT1, ..., BT24) or the further subset of these battery cells (BT1 ,. .., BT24) or battery cells of a further battery can be connected to the fourth connecting line (BL4) via a switching element (S11a, ..., S25). Transfer device according to one of the preceding claims, characterized in that the transfer device (2) has at least one means for detecting or determining a voltage across the capacitive element of a transfer branch (2, 4) and at least one means for detecting or determining a voltage across the inductive element of a transfer branch (2, 4). Method for operating a reloading device (1) according to one of the Claims 1 to 7 , characterized in that in a discharge state a first section of the series connection of all battery cells (BT1, ..., BT24) is connected to the recharging branch (2), with a further section of the series connection of all battery cells (BT1, ... , BT24) is connected to the recharging branch (2), at least one battery cell (BT1, ..., BT24) of the first section not being part of the further section. Procedure according to Claim 8 , characterized in that the first section comprises more battery cells (BT1, ..., BT24) than the further section. Procedure according to Claim 8 or 9 , characterized in that the first section comprises at least three battery cells (BT1, ..., BT24). Procedure according to one of the Claims 8 to 11 , characterized in that a switching time for establishing or separating a connection of a section of the series connection to the transfer branch (2) is selected such that an amplitude of the current (12) flowing through the transfer branch (2) is zero or no longer as a predetermined measure deviates from zero. Procedure according to one of the Claims 8 to 11 , characterized in that a voltage (UC) across the at least one capacitive element and a voltage (UL) across the at least one inductive element of the transfer branch (2) is determined or detected, a zero difference time (T _ND ) being determined, in which the voltage (UC) across the at least one capacitive element does not deviate from the voltage (UL) across the at least one inductive element, or does not deviate more than a predetermined amount, with a switching time for establishing or disconnecting a section of the series circuit from the Reloading branch (2) is determined as a function of the zero difference time (T _ND ). Procedure according to Claim 12 , characterized in that a time period between the zero difference time (T _ND ) and a reference time (T ₀ ) is determined, the switching time being determined such that a time period between the switching time and the reference time (T ₀ ) is three times the time period between the zero difference time (T _ND ) and the reference time (T ₀ ). Procedure according to one of the Claims 8 to 13 , characterized in that in a recharging state the at least one capacitive element of the recharging branch (2) is connected to at least one battery cell (BT1, ..., BT24) such that the capacitive element is recharged. Procedure according to one of the Claims 8 to 14 , characterized in that in a further discharge state a first section of the series connection of all battery cells (BT1, ..., BT24) is connected to a further transfer branch (4) and / or in a further state of charge a section of the series connection of all battery cells (BT1, ... ..., BT24) is connected to the further transfer branch (4). Vehicle with a battery and a transfer device (1) according to one of the Claims 1 to 7 .

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