CN110071339A - The method for controlling the method for the charging of battery assembly module and charging to battery assembly module - Google Patents

Abstract

The present invention relates to a method of controlling the charging of a battery cell and a method of charging a battery cell. A method for controlling the charging of a battery cell (10) with as short a charging time as possible while avoiding lithium electroplating, the method having the steps of determining (S1) the battery cell (10) on which it is based The current value of the overpotential margin (U(t)) of the anode; the current value of the internal resistance R(t) of the battery cell (10) on which the determination (S2) is based; the value of the quotient of the current value of the overpotential margin (U(t)) of the unit (10) and the current value of the internal resistance (R(t)); and according to the value of said quotient, according to the relational expression to set ( S4 ) the intensity and/or time course of at least one charging current (I _Lade (t)). The invention also relates to a method for charging, a control unit (50) for controlling charging, a charging system (110), a battery system (100) and a working device.

Description

Method of controlling charging of battery unit and method of charging battery unit

technical field

The present invention relates to a method for controlling charging of a battery unit, a method for charging a battery unit, a control unit for controlling charging, a charging system for charging, a battery Group system and a working device.

Background technique

In recent times, battery pack systems have been increasingly used to power work equipment and, in particular, vehicles for operating them. Here, battery cells based on lithium-ion chemistry are particularly important due to their high energy density and capacity. Problematic in such battery cells are safety issues, which also have to be taken into account in connection with the charging operation. Depending on the ambient and operating conditions and the lifetime of the respective battery cell, the applied charging current must not exceed a defined maximum limit so that no deposition of lithium on the anode, so-called lithium electroplating, occurs.

DE 11 2010 005 906 T5 describes a battery control system capable of properly charging a secondary battery while the deposition of metallic lithium on the negative plate is suppressed.

DE 10 2013 204 507 20 A1 relates to a method for monitoring a battery cell with a lithium deposition safety function for determining critical battery states and for transitioning the battery into a safe operating mode.

DE 10 2015 111 195 A1 discloses a charging method for a lithium-ion battery for adaptively charging a rechargeable battery, wherein the charging current is adapted to the parameters of the battery.

SUMMARY OF THE INVENTION

The invention is based on the task of providing a method for controlling the charging of a battery unit, a method for charging such a battery unit, a control unit for controlling the charging, a charging system , a battery system and a working device and in particular a vehicle, in which battery cells based on lithium-ion chemistry can be charged particularly efficiently by setting an optimum charging current in a flexible manner with particularly simple means Charge in order to keep the charging time as short as possible in particular.

Alternatively, the object on which the invention is based is solved by a subject matter having the features of one of claims 1 and 12 to 16 . Advantageous refinements are the subject of the corresponding subclaims.

According to a first aspect of the present invention, there is provided a method for controlling the charging of a battery cell based on lithium ion chemistry, the method having the steps of:

(i) determining the current value of the overpotential margin U(t) of the anode of the battery cell on which it is based;

(ii) determining the current value of the internal resistance R(t) of the battery cell on which it is based;

(iii) determine the value of the quotient of the current value of the overpotential margin U(t) of the battery cell on which it is based and the current value of the internal resistance R(t); and

(iv) According to the value of the quotient, the intensity and/or the time course of the at least one charging current I _Lade (t) is set according to the following relation (I):

(I).

For the purposes of the present invention, the term anode overpotential margin may be understood as the anode's ability to tolerate a certain overvoltage without the anode potential becoming negative. Technically, the overpotential margin U(t) of the anode corresponds in equilibrium to the equilibrium voltage of the anode relative to lithium, i.e. the value 𝑉 _neg /V vs. Li/Li ⁺ , and can be measured relative to the lithium electrode, for example by The half-cell anode is determined, ie, for example, by means of a measurement for determining the voltage OCV when the battery circuit is open (OCV: Open-Circuit-Voltage).

According to the invention, by means of the measures (i) to (iv) described above, it is achieved that the current value at a given point in time and the internal resistance of the battery cell at a given point in time are fully utilized for the overpotential margin of the anode of the battery cell. The charging current to be applied for charging the battery cells is set at the current values at the given point in time or estimated values close to these values. Such a set value of the charging current provides optimal charging results, wherein the charging process is run such that lithium electroplating has not yet occurred.

In an advantageous development of the method according to the invention, the above-mentioned steps (i) to (iv) are carried out repeatedly in real time such that the current value of the charging current is correlated with the underlying battery cell during the charging process. The current value of the overpotential margin and the internal resistance of the battery pack is adapted and/or kept adapted to the current value of the overpotential margin and the internal resistance of the battery cell on which it is based.

In particular, the process can continue as long as the charging conditions are met. The charging condition may consist of one or more individual conditions and may in particular describe the necessity to charge the underlying battery cell, for example the underlying battery is required due to falling below a lower threshold value of the state of charge of the underlying battery cell Necessity of group unit charging. In a vehicle, this charging condition can also be fulfilled, for example, when braking energy is recovered.

In principle, there are different possibilities for determining the required value of the overpotential margin of the anode of the battery cell and/or the internal resistance of the battery cell.

This can be a direct measurement or also an indirect method, which is determined on the basis of the state parameters and/or operating parameters of the underlying operating device, the underlying vehicle and/or the underlying battery cell, and in particular The current value of the overpotential margin of the anode of the battery cell and/or the internal resistance of the battery cell is estimated.

In this way, it is provided in a further advantageous embodiment of the method according to the invention that the current value of the overpotential margin is determined directly from the voltage measurement.

Alternatively or additionally it may be provided that the current value of the overpotential margin is determined by directly measuring the anode voltage of the anode of the battery cell with the battery circuit open, ie just like the open circuit voltage of the battery cell.

If the current value of the overpotential margin is determined by directly measuring the voltage of the half-cell anode of the battery cell at equilibrium relative to the lithium electrode, the method according to the invention provides a particularly accurate result of this current value.

For the determination of the internal resistance of the battery cell on which it is based, there are also different technical processing methods which can be used in the present invention.

If the value of the internal resistance is determined directly from the current measurement and the voltage measurement on the basis of a further advantageous embodiment of the method according to the invention, a particularly simple relationship which is still highly reliable occurs.

This can be achieved, for example, simply by applying and, if necessary, measuring a pulsed constant current to the battery cell and measuring the voltage response of the battery cell.

In order to also be able to detect more complex relationships with regard to the characteristics of the battery cells, according to a further embodiment of the method according to the invention, it is also possible to use a relationship between the evolution of the open-circuit voltage of the battery cells detected under equilibrium and the charging curve. The voltage difference between them determines the value of the internal resistance.

In a further embodiment of the method according to the invention, if the value of the internal resistance is based on the value of the internal resistance at the current point in time during operation, during operation at the full start of operation of the battery cell (BoL: begin of life (start of life)) and the value of the internal resistance at the point in time when the battery unit fully starts to operate, it is particularly reliable for the constant change of the characteristics of the battery unit during operation. possibility of revision and due consideration.

In this context, in particular when determining the value of the internal resistance of the battery cell on the basis of the following relation (II), a simple and reliable numerical determination is possible from the determined value:

, (II)

where R(t) represents the value of the internal resistance of the battery unit at the current time point t to be determined, R _Betrieb (t) represents the value of the internal resistance at the current time point t during operation, and R _Betrieb,BoL represents The value of the internal resistance at the time point when the battery unit fully starts to operate during operation, R _BoL represents the value of the internal resistance at the time point when the battery unit fully starts to operate, and b represents the proportionality coefficient. Here, R(t) is a parameter related to SoC like R _BoL . This parameter may also be related to the current, temperature, mechanical tension of the battery, for example. Here, SoC dependencies are key.

Here it is appropriate to determine the scaling factor b according to the following relation (III):

or , (III)

Namely as the change in the value of the internal resistance R _Betrieb (t) currently measured during operation relative to the change ΔR in the value of the internal resistance R or alternatively relative to the mean value of the internal resistance R The change business. Especially when the correlations mentioned above come into play, the mean of R as an alternative is reasonable. Without considering the correlation, R is a scalar.

In addition to direct measurement methods, which take voltage measurements and current measurements at the battery cells, indirect determination methods are also suitable.

Thus, an alternative processing method of the method according to the invention provides that the current value of the overpotential margin and/or the current value of the internal resistance of the battery cell is determined indirectly, in particular by reading out the values from a reading table and/or indirectly determining the current value of the overpotential margin and/or the current value of the internal resistance of the battery cell by reading out the value using addressing of the current measured state parameter and/or operating parameter of the battery cell .

It can be advantageous here that the battery cells on which they are based are pre-measured with regard to their relationship of the overpotential margin to the internal resistance in a previous pre-program, in particular in order to prepare a reading table.

The value of one or more parameters from the following parameter group with a battery pack can be used as the currently measured status parameter and/or operating parameter for addressing the readout from the readout table The state of charge of the cell, the charging time on the battery cell, the charging current of the battery cell, the service life of the battery cell, in particular from full operation, the pressure and/or mechanical tension of the battery cell and The temperature of the battery pack cells. Additionally or alternatively, other physical and/or chemical parameters can also be used for parameterizing and determining the overpotential margin and the internal resistance of the battery cells.

According to another aspect of the present invention, there is also provided a method for charging a battery cell, in particular a battery cell based on lithium ion chemistry.

The method according to the invention has the steps of supplying a charging current and charging the battery cells with this charging current. The charging current can be set using the method for controlling according to the invention. In this case, the charging current can be set synchronously like a control (open loop control) or like a regulation (closed loop control), taking into account other influencing variables.

Furthermore, the subject-matter of the invention is also a control unit for controlling the charging and in particular the charging current for charging a battery cell, in particular a battery cell based on lithium ion chemistry. The control unit is designed to implement the method according to the invention for controlling the charging and in particular the charging current of the battery cells and/or be used in the method according to the invention for charging the battery cells.

The control unit according to the invention can be designed as a battery management system or as part of a battery management system.

The present invention also provides a charging system for charging battery cells, especially based on lithium ion chemistry. The charging system is designed to be used and/or controlled in the method according to the invention for controlling charging, used and/or implemented in the method according to the invention for charging.

In particular, the charging system has a charging unit which can be connected to the battery unit and is designed to provide a charging current and to actuate the battery unit with this charging current. Furthermore, a control unit designed according to the invention for controlling the operation of the charging unit is part of the charging system.

The invention also proposes a battery system which is designed with at least one battery cell and has a charging system designed according to the invention, which is set up to supply the battery in a controllable manner The cells are charged and used for controllable electrical connection to the battery cells.

Finally, the subject-matter of the invention is also a working device which can be designed as a vehicle and/or which is designed with an electrically drivable device and a battery system designed according to the invention. Here, the battery system is designed to supply the device in a controllable manner with electrical energy for operating the device. The device can be, for example, a drive or part of a drive.

Description of drawings

Further details, features and advantages of the present invention emerge from the ensuing description and drawings.

FIG. 1 shows, in a combination of a block diagram and a flowchart, an embodiment of a battery system according to the invention with a charging system according to the invention and with a control unit according to the invention, which is designed to implement Embodiments of the method according to the invention for control and for charging.

2 to 6B illustrate aspects of an embodiment of the method for controlling and charging according to the present invention in the form of graphs.

FIG. 7 shows, in a combination of a block diagram and a flowchart, another embodiment of a method for controlling the charging of battery cells according to the present invention.

8 and 9 show in block diagram form other embodiments of a battery system, charging system and control unit according to the present invention.

Detailed ways

Subsequently, embodiments and technical backgrounds of the present invention are described in detail with reference to FIGS. 1 to 9 . Identical and equivalent and elements and components serving the same or equivalent functions are denoted by the same reference numerals. Detailed descriptions of the elements and components shown have not been reproduced in all instances where they appear.

The features and other characteristics shown may be separated from each other in any desired manner and may be combined with each other in any desired manner, without departing from the core of the present invention.

FIG. 1 shows an embodiment of a battery system 100 according to the invention with a charging system 110 according to the invention and with a control unit 50 according to the invention, which control unit is An embodiment of the method S for controlling charging and/or for charging according to the invention is provided.

The battery system 100 shown in FIG. 1 consists of a charging system 110 constructed in accordance with the present invention and a battery unit 10 connected to the charging system via first and second charging cables 1 , 2 . The first and second charging cables 1 and 2 are connected to the first and second connection ends 11 or 12 of the battery pack unit 10 with their first ends, and are connected to the first and second ends of the charging unit 40 with their second ends On the connection end 41 or 42, the charging unit can also be called a charging device. The charging unit 40 is set up to generate a corresponding charging current I _Lade for charging the battery unit 10 according to the control signal delivered via the control line 53; The first and second charging cables 1 and 2 are supplied to the battery unit 10 .

In an embodiment according to the invention, a control unit 50 is provided in order to set the charging current I Lade as a function of the value of the charging current I _Lade for charging the battery unit 10 . The control unit 50 is capable of detecting certain operating parameters of the battery unit 10 and/or via the detection and control line 54 and via the first and second signal lines 51 or 52 connected to the first and second charging lines 1 and 2 Status parameters, on the basis of which the value of the charging current I _Lade is _generated and supplied to the charging unit 40 via the control line 53 , eg in the form of a corresponding control signal.

In the control unit 50 itself, an embodiment of the method S according to the invention for controlling the charging and in particular the charging current I _Lade for charging the battery unit 10 is run.

First, it is determined in the preceding checking step S0 whether or not the charging conditions are satisfied. The charging conditions may consist of one or more individual conditions and specify whether or not the underlying battery cell 10 is to be charged at all.

If the charging conditions are not met, corresponding to "NO" in step S0, the actual method S for controlling the charging and/or charging current is left and returns to the higher-level processing steps.

Whereas, if the charging condition is satisfied, corresponding to "Yes" in step S0, the subsequent steps S1 to S4 are executed with jumping back to step S0.

First, in step S1 , the current value U(t) of the overpotential margin of the anode of the battery cell 10 is determined in a manner according to the invention, which should be determined by direct measurement or indirectly by reading a table.

In the subsequent step S2, the current value of the internal resistance R(t) of the battery cell 10 is determined.

In the following step S3, the current value of the charging current I _Lade is calculated by means of a corresponding quotient, in particular by means of a corresponding quotient with full use of Ohm's law.

In step S4 following this, the strength of the actual charging current I _Lade is set, in particular by giving the charging unit 40 a control signal representing the value of the rechargeable battery I _Lade using the control line 53 . Determine the strength of the actual charging current I _Lade .

FIGS. 2 to 6B show a method S according to the invention for controlling the charging of battery cells 10 and/or for charging battery cells 10 in the form of graphs 20 , 25 , 30 , 35 , 60 , 65 . aspects of the implementation.

FIG. 2 shows by way of example the value of the overpotential margin U(t) of the anode of the battery cell 10 depending on the state of charge SoC by means of the trace 23 in a graph 20 , which has a horizontal Coordinate 21 and has an ordinate 22 on which the value in % of the state of charge SoC is plotted, on which the overpotential margin U(t) of the anode of the battery cell 10 is plotted The value in relative units. The following profile is obtained, in which the overpotential margin U(t) decreases approximately monotonically as the value of the state of charge SoC increases.

FIG. 3 shows by way of example traces 28 - 1 to 28 - 3 in graph 25 the values of the internal resistance R(t) of the anode of the battery cell 10 based on the state of charge SoC, that is to say Said graph 25 shows the dependent value of the internal resistance R(t) of the anode of the battery cell 10 depending on the state of charge SoC according to the increasing ageing which is symbolically represented by the direction of the arrow 29 . There is an abscissa 26 on which the value in % of the state of charge SoC is plotted and an ordinate 27 on which the value of the internal resistance R(t) of the battery cell 10 is plotted in %. The value in relative units.

FIG. 4 schematically shows on the basis of the graph 30 the scaling factor b for determining the adaptation of the value of the internal resistance R(t), in particular on the basis of the relationships (III) and (5), for determining the adaptation of the internal resistance R( The value of t) is adapted to the fundamental aspect of the scaling factor b. The averaged resistance is plotted on the abscissa 31 and the internal resistance R _Betrieb determined during operation is plotted on the ordinate 32 . The measurement points 34 and their fitted lines 33 are respectively drawn. Fitted line 33 is used to determine the scaling factor b from the sloped triangle.

FIG. 5 shows by way of example traces 38 - 1 to 38 - 3 in graph 35 the value of charging current I _Lade of battery cell 10 as a function of state of charge SoC, that is to say as a function of increasing internal The resistance R(t), whose rise is symbolically represented by the direction of the arrow 39 , shows the value of the charging current I _Lade of the battery cell 10 depending on the state of charge SoC, the graph 35 having the abscissa 36 and having The ordinate 37 is plotted on the abscissa 36 with the value in % of the state of charge SoC, and the value in relative units of the charging current I _Lade of the battery cell 10 is plotted on the ordinate 27 .

6A and 6B illustrate, in the form of graphs 60 and 65, aspects for determining the internal resistance R(t) of the battery cell 10 on which it is based. The battery cell 10 is loaded with a current pulse, as shown by the trace 63 in the graph 60 of FIG. 6A . The voltage response of the battery cell 10 shown as trace 68 in graph 65 in FIG. 6B is obtained.

In the graph 60 the time t is plotted on the abscissa 61 and the value of the applied current I is plotted on the ordinate 62 . The current changes from the value I ₀ to the increased value I ₁ at time t ₀ and returns to the initial value I ₀ at a later time t ₁ .

In the graph 65 , the time t is plotted on the abscissa 66 and the value of the battery voltage U is plotted on the ordinate 67 . It can be seen that the corresponding charge and discharge curves appear with the change of the current amplitude at time points t ₀ and t ₁ , that is, at successive time points t ₀ , t ₁ ′, t ₁ , t ₂ have corresponding values U ₀ , U ₁ ′, U ₁ , U ₂ , these values can be analyzed in conjunction with relations (2) and (3), as described in more detail below.

FIG. 7 shows a further embodiment of a method T according to the invention for controlling charging and/or for charging a battery cell 10 in a combination of a block diagram and a flow chart.

In a first step T1, the overpotential margin U(t) of the anode of the battery cell 10 is determined as a basic parameter or basic function, in particular the previous current value is determined and provided. In a second step, the internal resistance R(t) of the battery cell 10 is determined and provided, in particular with respect to the respective current value at the point in time t. In steps T4-1 to T4-3, the value of the internal resistance R _Betrieb,BoL of the battery cell 10 at the start of full operation (BoL, begin of life) during operation, the value of the battery cell 10 during operation are determined The current value of the internal resistance R _Betrieb and the relative changes of these parameters to each other. In step T4-4, the proportionality coefficient b that has been described above is determined and added to the internal resistance R(t of the battery cell 10 by addition in step T4-6 through multiplication in step T4-5 ) of the value determined in step T2. Then, in a subsequent step T3, a quotient is performed to obtain the optimized charging current I _Lade (t).

8 and 9 show in block diagram form other embodiments of the battery system 100, the charging system 110 and the control unit 50 according to the present invention.

In the embodiment according to FIG. 8 , the battery cell 10 consists of a single lithium-ion battery. The setpoint value of the charging current I _Lade (t) is supplied to the charging device 40 as a function of time via the control line 53 with a corresponding control signal. For this purpose, the control unit 50 has a controller 45 . The control unit 50 is supplied by the sensor 13 via the corresponding detection and control line 54 with corresponding control signals, eg actual voltage, temperature and actual current, and then on the basis of these control signals the charging current to be set is determined according to the invention I _Lade (t) control signal.

Unlike the embodiment according to FIG. 8 , in the embodiment according to FIG. 9 , the battery cell 10 on which it is based has a plurality of lithium-ion cells. Each individual lithium-ion battery of the battery unit 10 is constructed with a set of sensors 13 , which transmit their values via corresponding detection and control lines 54 to a control unit 50 , wherein the control unit 50 can be used here as a control unit. The controller or battery management system 46 may be configured as or may be configured as part of the controller or battery management system 46 .

These and other features and characteristics of the invention are set forth below and are further explained on the basis of possible embodiments of the invention:

The invention also relates, in particular, to a battery and a corresponding battery for the function of basic variables or basic functions, eg also including the open circuit voltage U(t) or OCV (open circuit voltage) at the anode, ie the anode voltage when the circuit is open The internal resistance R(t) of the battery cells (understood as battery cells 10 ) depends on the Soc (SoC: state of charge, in English) to determine and in particular to calculate the improved or maximum resistance of the lithium-ion battery 10 . The optimum charging current I _Lade is determined, in particular by the adaptation of the charging current I _Lade in the event of an increasing aging of the battery cells 10 , and the improved or optimal charging current I of the lithium-ion battery 10 is calculated in particular _Lade 's method S.

What is important for the use of the battery cells 10 is the available capacity and the maximum power that can be used. Over time and due to the charging and discharging process, the capacity (SoH: state of health) decreases and the internal resistance R(t) increases, whereby the working capacity of the battery cell 10 decreases, commonly known as aging or service life.

Charging, and in particular rapid charging, leads to accelerated aging of the battery cells 10 . Today, fast charging is of increasing importance for the improved everyday usability of electric vehicles. In order to minimize the negative effects of this fast charging with the shortest charging duration, an optimized charging strategy is required.

The starting point of the invention is that the charging and discharging processes of the battery cells 10 lead to the aging of the battery cells 10 . Particular damage due to rapid charging, in particular due to so-called lithium electroplating, is also known.

Lithium electroplating, ie the deposition of metallic lithium on the anode surface when charging the battery cell 10, leads to ageing of the lithium-ion cell 10 and is therefore to be avoided. Lithium electroplating occurs once the potential of the anode relative to lithium, i.e. 𝑉 _neg /V vs. Li/Li ⁺ , drops to a value below 0V.

Overvoltage during charging reduces the anode potential and causes the potential on the anode to drop to a value below 0V during the charging process.

When these conditions are met depends on different conditions.

In addition to the material properties of the battery 10 , other operating conditions such as charging current, state of charge (SoC: State of Charge) and temperature are also important.

To avoid lithium electroplating, ie deposition of metallic lithium on the anode, the charging current I _Lade can be reduced, thereby increasing the required charging time.

However, the anode has a so-called overpotential margin, which makes it possible to tolerate a certain overvoltage (denoted here by U(t)) without the anode potential becoming negative.

This overpotential margin U(t) is greater in the case of a low state of charge SoC than in the case of a higher state of charge, as is also clear from FIG. 2 . Therefore, a higher charging current I _Lade can be tolerated when the state of charge SoC is low, without the potential on the anode falling below 0V.

If the anode potential assumes a value of 0V during the entire charging process, the greatest reduction in charging time without lithium electroplating is achieved.

Although it is also possible to determine the maximum charging current with the aid of a reference electrode and/or using test cells.

In this case, the anode potential is measured during operation and the maximum tolerable charging current is thus determined as a function of the state of charge SoC and the temperature. However, this is associated with an increased measurement outlay due to the additionally required reference electrode and possibly the design of the test cell. Additionally, the test batteries differ in their properties and/or their geometry from batteries used in applications (eg BEV: battery electric vehicle). The reference electrode may also affect the electrochemical properties of a real battery. For these reasons, it is difficult to transfer measurements to batteries in this application (eg BEV). Additionally, optimal operating conditions change as the battery ages.

Solutions that utilize reference potentials and/or test cells do not take these changes into account.

This aspect may lead to the fact that the charging current may be increased without the anode potential falling to a value below 0V. In this case, the drop potential during the charging time is not fully utilized. On the other hand, however, this can also lead to the fact that the anode potential drops to a value below 0V and the cell is irreversibly damaged.

According to the invention, in order to calculate the optimized charging current I _Lade , the overpotential margin U(t) of the anode is detected as a basic variable or basic function, for example as a function of the state of charge SoC of the battery cells 10 and/or as a function of other A parameter, such as the temperature and/or ageing of the battery cell 10 on which it is based, is used to detect the overpotential margin U(t) of the anode, as a basic parameter or basic function.

For this purpose, an overpotential allowance U _neg := U _neg (SoC, T, ...) of the anode can be used, for example. This overpotential margin can be determined, for example, by measuring the anode OCV or the open circuit voltage of the anode, as shown in connection with FIG. 2 .

Furthermore, the internal resistance R(t) of the battery 10 and in particular the internal resistance R(t) and/or the change in the internal resistance in the charging direction are detected as a function of the state of charge SoC, ie in particular with respect to R:=R(SoC). The portion formed only due to the insertion process of lithium ions into the anode.

However, alternatively or additionally, the dependence of the charging time t, preferably in the time range of a few milliseconds to a few hours, the charging current I, the temperature T and the state of charge SoC, is preferably detected, as this is combined with As shown in FIG. 3, in particular with respect to R:=R(SoC, T, t, I).

The SoC-dependent internal resistance R(t) can be determined, for example, by the voltage difference between the OCV curve recorded in the equilibrium state and the charging curve of the battery cell 10 on which it is based.

According to the following relationship (1):

(1)

And in particular according to Ohm's law, the optimized charging current I _Lade to be used to charge the battery cell 10 on which it is based is obtained as the value of the determined overpotential margin U(t) as a basic parameter or basic function Quotient with the value of the internal resistance R(t).

The charging current I _Lade is thus optimized to a maximum value, while the anode potential just does not drop below 0 V during the entire charging process and the condition 𝑉 _neg /V vs. Li/Li ⁺ ≥ 0 is satisfied. The result is a reduction in charging time to a minimum.

For applications in battery operation, the charging current I _Lade can optionally be adapted to the continuous aging of the underlying battery. The internal resistance R can be determined according to the charging time t, the current I, the pressure p and/or tension, the temperature T and/or the state of charge SoC.

There is also the possibility of determining values only for quasi-static states, that is to say independently of charging time t, current I, pressure p and/or tension, temperature T and/or state of charge SoC.

An exemplary method for determining the internal resistance R during operation is shown in conjunction with FIG. 7 .

There, through relations (2) and (3), that is, as follows

(2)

(3)

The internal resistance R _Betrieb from the operation of the battery cell 10 on which it is based is obtained, wherein the associated times t ₁ ′, t ₁ , t ₂ can take values in the range of milliseconds to hours.

The determination of the internal resistance R _Betrieb at runtime can also be carried out by any other method, which is already known or is still being developed.

According to the change of the internal resistance R _Betrieb measured during operation, for example in the vehicle, relative to the internal resistance R _Betrieb,BoL measured during operation at BoL By means of the resistance R _BoL at the BoL, ie the point in time at which the battery cell 10 fully starts to operate, and the proportionality factor b of the internal resistance R can be estimated during operation, for example based on the following relation (4):

, (4)

The resistance R _BoL can be understood to depend on the charging time t, the current I, the pressure p (tension), the temperature T and/or the state of charge SoC, and the internal resistance R can also be understood as being dependent on the charging time t, the current I, Pressure p (tension), temperature T and/or state of charge SoC.

The scaling factor b can be determined, for example, by upstream measurements on battery cells, preferably battery cells of the same battery type.

To this end, it can be understood that the value of the internal resistance R of the SoC depending on the charging time t, the current I, the pressure p (strain), the temperature T and/or the state of charge SoC can be repeatedly measured with respect to the ageing of the battery cells 10 , As this is shown in conjunction with FIG. 3 .

Following these measurements, the resistance is also determined, as this resistance might be measured during operation. The scaling factor b is based on the mean value of R _Betrieb relative to R or alternatively only relative to R, i.e. The quotient of the change (as this is also shown schematically in conjunction with Fig. 4) is obtained by the following relation (5):

or (5).

In the case of equation (1), the optimized charging current I _Lade can be determined with the internal resistance adapted according to equation (4), as explained further in connection with FIG. 5 .

This enables the determination of an optimized charging current I _Lade with minimal charging time over the entire battery life without causing increased battery aging and not fully utilizing the anode's overpotential margin.

The calculation process is schematically explained with reference to FIG. 7 .

This method can be used not only for the charging process of a single cell 10 but also for the charging process of a plurality of battery cells connected in series. In this case, for example, a controller, preferably a controller as a component of a BMS unit (BMS: battery management system), transmits the target current value according to equation (1) to the charging device.

The method is further explained in conjunction with FIGS. 8 and 9 . When applying the method in a battery-operated electric vehicle (BEV), the charging device 40 can be built either in the vehicle itself or in a charging station.

Unlike the known methods, for the application of the charging design, it is not necessary to perform measurements on the test cell and/or the reference electrode to optimize the anode potential to a value of 0V. It is also possible to adapt the charging current I _Lade to the constant aging during operation by means of simple measurements. This adaptation is helpful, since a higher overvoltage U(t) can lead to a more severe drop in the anodic potential due to constant aging and thus to a negative anodic potential.

Some core aspects of the present invention are:

(1) describe a method and/or apparatus for charging battery cells 10 or battery system 100;

(2) Determine the charging current I _Lade by using the registered comprehensive characteristic curve and measuring the actual parameter on the battery cell 10 or the battery system 100;

(3) Make full use of the overpotential margin U(t) on the anode side during charging; and/or

(4) Establish and/or provide a closed-loop control circuit composed of the charging device 40 , the battery management system, and the battery cells 10 or the battery system 100 .

The embodiments according to FIGS. 7 , 8 and 9 are preferred.

The internal resistance determination can be carried out according to Figure 6, alternatively it would be possible to use electrical consumers to generate the current distribution.

In the embodiments according to FIGS. 7 , 8 and 9 , a closed-loop control circuit is used to determine the internal resistance R(t). Additional components can be integrated in the embodiment according to FIG. 6 .

According to the invention, in particular the following advantages over conventional methods arise:

(A) optimizing the charging of battery cells 10 or battery system 100 with respect to aging effects;

(B) reducing the charging time to the minimum value that is optimal for the service life;

(C) eliminates additional component costs, such as those associated with test cells or reference electrodes; and/or

(D) Introducing a charging method based on overpotential on the anode side.

Even though aspects and advantageous embodiments in accordance with the present invention have been described in detail with reference to the embodiments set forth in connection with the accompanying drawings, modifications and features of the illustrated embodiments will be apparent to those skilled in the art. Combinations are also possible without departing from the scope of the invention, which is defined by the appended claims.

List of reference signs

1 (first) charging cable

2 (second) charging cable

10 battery pack units

11 (first) connection end

12 (second) connector

13 Sensors

20 Graph (overpotential margin)

21 Abscissa

22 Ordinate

23 track

25 Graph (internal resistance at aging)

26 Abscissa

27 Ordinate

28-1 Track

28-2 Track

28-3 Track

29 Aging increases

30 Graph (scale factor)

31 Abscissa

32 Ordinate

33 Tracks

34 measuring points

35 Graph (charging current at aging)

36 Abscissa

37 Ordinate

38-1 Track

38-2 Track

38-3 Track

39 Internal resistance R(t) rises

40 charging unit

41 (first) connection end

42 (second) connector

45 Controller

46 Battery Pack Management System

50 Control unit

51 (first) signal line

52 (second) signal line

53 Control wire

54 Detection and control lines

60 Graph (current pulse)

61 Abscissa

62 Ordinate

63 Tracks

65 Graph (Voltage Response)

66 Abscissa

67 Ordinate

68 tracks

100 battery pack system

110 Charging system

S Method used to control

S0 asks for charging conditions

S1 Determines the current value of the anode's overpotential margin U(t)

S2 Determine the current value of the internal resistance R(t) of the battery pack unit 10

S3 determiner

S4 Set the charging current I _Lade (t)

Claims (16)

1. the method (S) of charging of the one kind for controlling battery assembly module (10), the method have following steps:

(i) current value of the overpotential allowance (U (t)) of the anode for the battery assembly module (10) that (S1) is based on is determined；

(ii) current value of the internal resistance (R (t)) for the battery assembly module (10) that (S2) is based on is determined；

(iii) current value and internal resistance (R of the overpotential allowance (U (t)) for the battery assembly module (10) that (S3) is based on are determined (t)) value of the quotient of current value；And

(iv) according to the value of the quotient, (S4) at least one charging current (I is set according to following relationship formula (I)_Lade(t)) Intensity and/or time-varying process:

(I).

2. according to the method for claim 1 (S), as long as wherein meet charge condition, step (i) to (iv) weighing in real time It is implemented as again so that the charging current (I_Lade(t)) current value during the charging process with the battery pack list that is based on The overpotential allowance (U (t)) of first (10) and the current value adaptation of internal resistance (R (t)) and/or holding and the battery assembly module being based on (10) the current value adaptation of overpotential allowance (U (t)) and internal resistance (R (t)).

3. method (S) according to one of the above claims, wherein directly determining the overpotential according to voltage measurement The current value of allowance (U (t)), and/or by directly measuring the battery assembly module under conditions of battery circuit is opened a way (10) anode voltage of anode determines the current value of the overpotential allowance (U (t)).

4. according to the method for claim 3 (S), wherein positive by the half-cell for directly measuring the battery assembly module (10) Pole determined the current value of the overpotential allowance (U (t)) relative to the voltage of lithium electrode at equilibrium.

5. method (S) according to one of the above claims, wherein directly being determined according to current measurement and voltage measurement The value of the internal resistance (R (t)), and/or by applying and to measure pulse on the battery assembly module (10) permanent when necessary Fixed electric current and the voltage responsive of the battery assembly module (10) is measured to determine the value of the internal resistance (R (t)).

6. method (S) according to one of the above claims, wherein based on the battery pack detected at equilibrium Voltage difference between the change procedure and charging curve of the open-circuit voltage of unit (10) determines the value of the internal resistance (R (t)).

7. method (S) according to claim 5 or 6, based at runtime in the internal resistance (R at current time point_Betrieb (t)) value, at runtime in the internal resistance (R at the time point of the battery assembly module (10) to start running completely_Betrieb,BoL) Internal resistance (the R of value and the time point to start running completely in the battery assembly module (10)_BoL) value determine the internal resistance (R (t)) value.

8. according to the method for claim 7 (S), wherein determining the internal resistance (R (t)) based on following relationship formula (II) Value:

, (II)

Wherein R (t) indicates the value to be determined of the internal resistance, R_Betrieb(t) it indicates at runtime current time point t's The value of the internal resistance, R_Betrieb,BoLIt indicates at runtime at the time point of the battery assembly module (10) to start running completely The value of the internal resistance, R_BoLIndicate the value in the internal resistance at the time point of the battery assembly module (10) to start running completely And b indicates proportionality coefficient.

9. according to the method for claim 8 (S), wherein determining proportionality coefficient b according to following relationship formula (III):

Or, (III)

I.e. as the internal resistance R currently measured at runtime_Betrieb(t) variation of the variation of value relative to the value of internal resistance RΔROr Person's average value relative to internal resistance R as an alternativeVariationQuotient.

10. method (S) according to one of the above claims, wherein by using about the battery assembly module (10) The battery assembly module (10) is determined indirectly from readout is read in table in the addressing of currently measured operating parameter The current value of overpotential allowance (U (t)) and/or the current value of internal resistance (R (t)).

11. according to the method for claim 10 (S), wherein by the value of one or more parameters in following parameter group As currently measured for the operating parameter being addressed from the reading read in table, the parameter group to have described The charged state (SoC) of battery assembly module (10), the charging time on the battery assembly module (10), the battery assembly module (10) the service life of charging current, the battery assembly module (10), the pressure of the battery assembly module (10) and the electricity The temperature (T) of pond group unit (10).

12. method of the one kind for charging to battery assembly module (10), the method have following steps:

(a) charging current (I is provided_Lade)；And

(b) with the charging current (I_Lade) the load battery assembly module (10),

Wherein using setting the charging current (I to method described in one of 11 according to claim 1_Lade).

13. one kind is for controlling charging and/or controlling the charging current (I for charging to battery assembly module (10)_Lade) control Unit (50), described control unit is established as: implementing method according to one of claims 1 to 12 and/or the control Unit processed is configured to batteries management system or is configured to the part of batteries management system.

14. charging system (110) of the one kind for charging to battery assembly module (10),

The charging system is established as: used in the case where according to claim 1 to method described in one of 11 and/ Or it is controlled, and/or this method is used and/or implemented in the method according to claim 11；And/or

The charging system has

(I) charhing unit (40) that can be connect with the battery assembly module (10), the charhing unit, which is configured to provide, to be filled Electric current (I_Lade) and be used for the charging current (I_Lade) the load battery assembly module (10), and

(II) control unit (50) according to claim 13, for controlling the operation of the charhing unit (40).

15. a kind of battery pack system (100), includes

At least one battery assembly module (10)；With

Charging system (110) according to claim 14, the charging system are configured for controllably It charges and is used for and controllable being electrically connected of the battery assembly module (10) to the battery assembly module (10).

16. a kind of working equipment, includes

It can electrically driven (operated) equipment；With

Battery pack system (100) according to claim 15, the battery pack system are configured for controllable Mode supplies electric energy to the equipment, for running the equipment.