DE102020212769A1 - Method for the uninterrupted operation of a network-independent mobile system and mobile system - Google Patents

Abstract

The invention describes a method for the uninterrupted operation of a network-independent mobile system (1) for supplying a general load (50). The mobile system (1) includes a battery system (10) with a plurality N of battery units (11-1, ..., 11-n). A current regulator (21-1, ..., 21-n) is assigned to each of the rechargeable battery units (11-1, ..., 11-n) in order to regulate the current output of each of the rechargeable battery units (11-1, ..., 11 -n) to be set individually. A charge determination unit (30) determines a current charge (Qn) and a current total charge (Qtot) available in the battery system (10) for each of the rechargeable battery units (11-1, . . . , 11-n). A computing unit (40) controls the current controller (21-1, ..., 21-) depending on the current charge (Qn) of the N battery units (11-1, ..., 11-n) and the current total charge (Qtot). n). The method comprises the following steps: determining the current charge (Qn) of each of the battery units (11-1, ..., 11-n); Assigning a number O of the plurality N of battery units (11-1, ..., 11-n) to a first group (Grp_I) of battery units, wherein in the first group (Grp I) the battery units with the highest current charge (Qn ) are included; Assigning the remaining number P of the plurality N of battery units (11-1, ..., 11-n) to a second group (Grp_II) of battery units, wherein in the second group (Grp_II) those battery units with the least current charge (Qn ) are included and where: P = N - Q; Discharging the battery units (11-1, ..., 11-n) until a predetermined residual charge (Rtot) is reached, the residual charge (Rtot) being that charge which is discharged during a change to the second group (Grp_II). Battery units associated battery units (11-1, ..., 11-n) is required by charged battery units to supply the general load (50) without interruption during the change; Supplying the general load (50) from the battery units (11-1, ..., 11-n) belonging to the first group (Grp I) of battery units until the replacement of the battery units belonging to the second group (Grp_II) of discharged battery units (11-1, ..., 11-n) is completed by charged battery units.

Description

The invention relates to a method for the uninterrupted operation of a network-independent mobile system and a network-independent mobile system.

Mobile electrical systems such as communication, computer or robot systems are equipped with power supply units that provide a mains-independent (wireless) power supply. In order to ensure permanent mains-independent operation of the mobile system, these energy supply units must be charged when they are discharged, which entails a pause in the mobile system. If the mobile system has an exchange system for the energy supply unit with at least two battery units, the mobile system can continue to be operated with the other battery unit while one battery unit is being replaced.

In the case of such energy supply units designed as an exchangeable system, all battery units of the energy supply unit are usually discharged simultaneously and evenly. The consequence of this is that all the rechargeable battery units of the energy supply unit become empty at about the same time. In order to enable uninterrupted operation of the mobile system, it is necessary to replace the battery units with fully charged battery units before they are completely discharged. During the exchange or changing process, the mobile system is supplied with power via the other rechargeable battery units that are contained in the mobile system and that have sufficient charge. However, since the battery units must always be changed at a point in time when the battery units that have been exchanged or replaced are still charged, this means losses for the mobile system with regard to the running time between an exchange or change of battery units.

In another variant, the rechargeable battery units of the energy supply unit could be discharged simultaneously, undefined independently and unevenly from one another, which, however, makes a deterministic exchange of respective rechargeable battery units more difficult.

In addition, the possibility could be provided to switch between individual battery units in order to discharge them in a defined manner and not at the same time. However, this also has a disadvantageous effect on the running time of the mobile system, since the system power is drawn from individual battery units of the energy supply unit instead of from all of them. This leads to a lower energy yield due to the well-known Peukert effect, higher losses at the internal resistance of a respective battery unit and an earlier end of discharging due to the internal resistance-related earlier reaching of the end-of-charge voltage due to the higher discharging currents.

The object of the invention is to specify a method for the uninterrupted operation of a mobile system that is operated independently of the mains and a mobile system that can be operated independently of the mains, which is functionally improved and enables optimized energy utilization of the energy available in its energy supply unit.

These objects are achieved by a method according to the features of claim 1 and a device according to the features of claim 11. Advantageous refinements result from the dependent claims.

According to a first aspect of the present invention, a method for the uninterrupted operation of a network-independent mobile system is proposed. The mobile system is, for example, a communication system, a computer system or a robot system. The mobile system can also include functions of communication, computing and robotic components in any combination. For example, the mobile system is an assistance robotic system or a mobile transport system used for logistics.

The mobile system includes a battery system with a plurality N of removable battery units that can be recharged outside of the mobile system. A rechargeable battery unit (also referred to as an accumulator or rechargeable battery) is a rechargeable galvanic element that consists of two electrodes and an electrolyte and stores electrical energy on an electrochemical basis. A rechargeable battery unit can include any number of different storage elements (also referred to as secondary element or secondary cell), which are connected in a suitable manner in series and/or in parallel. A series connection of several storage elements enables the usable electrical voltage to be increased. A parallel connection of several storage elements enables the usable capacity to be increased and is suitable for higher current intensities. Both circuit variants allow a specified total energy content, specified in watt hours (Wh) of the respective battery unit. The plural number N is two or more. The accumulator units are arranged in such a way, for example in a housing, in the accumulator system that they can be removed from the accumulator system, for example manually or by means of an automated gripping unit, can be removed and reinserted. The battery units are not recharged within the mobile system, but on an external charger.

The mobile system also includes a current control unit with the plurality N of current controllers. In this case, each of the battery units is assigned a current controller in order to set the current output of each of the battery units individually and independently of the other battery units. A respective current regulator can be designed, for example, in the form of a current-regulating switching regulator. This equalizes the voltage differences between the voltage of the connected battery unit and the power supply bus and can generate a current flow between the battery unit and the power supply bus that is defined in terms of direction and strength through an external specification.

The mobile system also includes a charge determination unit, which is designed to determine a current charge and a current total charge available in the battery system for each of the battery units. The current total charge available in the accumulator system is determined from the sum of all current charges of each of the plurality N of accumulator units.

A computing unit of the mobile system is designed to control the plurality N of current controllers of the current control unit depending on the current charge of the plurality N of rechargeable battery units and the current total charge. The arithmetic unit is therefore intended to load the individual current controllers with desired values depending on a method it executes, so that they can set the current output of each of the rechargeable battery units individually and independently.

Finally, the mobile system includes a general load. The general load includes consumers contained in the mobile system, such as electric drives for autonomous, semi-autonomous or controlled movement of the mobile system, for performing movements of mechanical gripping, holding or moving means, input and output units of a user interaction interface, lighting units, audio - and/or video units and the like. The general load thus represents all consumers present in the mobile system, which are supplied with energy from the accumulator system for their operation. The load, consisting of one or more consumers, is connected to the current regulators by means of a common power supply bus.

The procedure includes the following steps:

In a step a), the current charge of each of the rechargeable battery units is determined.

In a step b), a number O of the plurality N of rechargeable battery units is assigned to a first group of rechargeable battery units. The number O of the plurality N of rechargeable battery units thus represents a partial number of the plurality N of rechargeable battery units. The first group of rechargeable battery units contains the rechargeable battery units with the highest current charge of the plurality N of rechargeable battery units. The number O of the plurality N can in principle be chosen arbitrarily. It is useful if the number O is approximately half of the number N, i.e. O ≈ 0.5 N.

In a step c), the remaining number P of the plurality N of rechargeable battery units is assigned to a second group of rechargeable battery units, the second group containing those rechargeable battery units with the least current charge of the plurality N of rechargeable battery units. The relation between the number O, the number P and the plural number N is as follows: P = N - O. If the number O is approximately half of the plural number N, i.e. O ≈ 0.5 N, then the number is P also in about half of the plural number N, i.e. P ≈ 0.5 N.

In a step d), the battery units are discharged until a predetermined residual charge is reached. The remaining charge is that charge which is required during a change from the battery units belonging to the second group of discharged battery units to charged battery units in order to supply the general load without interruption during the change. It follows from this that the remaining charge must be applied by the battery units belonging to the first group of battery units.

Step e) comprises supplying the general load from the battery units belonging to the first group of battery units until the replacement of the battery units belonging to the second group of discharged battery units with charged battery units is completed.

The method according to the invention enables continuous operation of the network-independent mobile system. Gentle discharging and an optimal energy yield of the battery units of the accumulator system are ensured. The method allows in particular that no battery units remain unused in the battery system, but all battery units from the first and second group - with the exception of the time period of changing to the second group of discharged batteries units associated battery units - can be discharged. After changing the initially discharged battery units of the second group, the fully charged battery units of the second group then ensure the supply of the mobile system, so that the units of the first group can be changed when they are discharged.

In an expedient embodiment it is provided that the battery units of the battery units belonging to the first group and of the battery units belonging to the second group are discharged in order to supply the general load until a predetermined residual charge is reached. In other words, according to this refinement, all battery units are always discharged for supplying the general load. When the predetermined residual charge is reached, which initiates a change of the battery units belonging to the second group, the battery units belonging to the first group of battery units are then supplied with power while the discharged battery units of the battery units belonging to the second group are being changed. As a result, no battery units remain unused in the mobile system or its battery system.

A further expedient embodiment provides that the battery units belonging to the first group and the battery units belonging to the second group are discharged with a different load proportion. This procedure discharges the battery units of both groups, i.e. the first and the second group, at the same time. However, the rechargeable battery units in one group, namely the rechargeable battery units belonging to the first group, are discharged more slowly than the rechargeable battery units in the other group, namely the rechargeable battery units belonging to the second group. During the change of the faster discharged group (second group), the supply of the mobile system is ensured by the other (first) group. After changing the battery units, which initially discharged more quickly, their fully charged battery units ensure the supply of the system, so that the battery units of the other group can be changed.

A further expedient embodiment provides that the battery units of the battery units belonging to the first group are discharged with a load component which is lower than the load component of the battery units belonging to the second group. The discharging of the battery units of the battery units belonging to the second group with a higher load proportion thus causes faster discharging than the battery units belonging to the first group.

A further expedient embodiment provides that the battery units belonging to the second group of battery units are completely discharged. This enables the energy retention of the second group of battery packs to be fully utilized. During the exchange of the battery units belonging to the second group of battery units, the energy supply is ensured by the battery units belonging to the first group.

It is also expedient if, in addition, the battery units belonging to the first group of battery units are completely discharged after changing the battery units belonging to the second group of battery units. This results in a maximum energy yield of the energy content provided by the accumulator system.

A further expedient embodiment provides that the battery units belonging to the first group are discharged by the respective current regulators in such a way that the respective current draw follows a predetermined first discharge curve for the first group of battery units and the battery units belonging to the second group are discharged by the respective Current regulator takes place in such a way that the respective current draw is a predetermined second discharge curve for the second group of battery units. This can be realized by comparing the relative state of charge of the respective battery units with the relevant discharge curve that applies to them. The first and the second discharge curve thus represent target discharge curves, with the respective current controllers regulating in such a way that they set the required current output individually and independently of the other rechargeable battery units in order to achieve the best possible match between the actual discharge curve and the specified discharge curve. In particular, the first discharge curve comprises two or more straight line sections. The second discharge curve expediently comprises a single straight line section. The point of intersection of the two straight sections of the first discharge curve expediently coincides with reaching the residual charge, at which point the only straight section of the second discharge curve has dropped to 0%, i.e. when the battery units belonging to the second group are discharged.

• Wechsel der zu der zweiten Gruppe gehörigen Akkueinheiten, gefolgt vom einem Wechsel der zu der ersten Gruppe gehörigen Akkueinheiten, gefolgt von einem Wechsel der zu der zweiten Gruppe gehörigen Akkueinheiten, usw.

A further expedient embodiment provides that steps a) to c) are initially carried out when the plurality N of rechargeable battery units is fully charged in each case. Steps d) and e), however, are carried out iteratively in order to ensure the continuous operation of the mobile system by successively changing the to ensure that the battery units belonging to the two groups:

• Changing the battery packs belonging to the second group, followed by changing the battery packs belonging to the first group, followed by changing the battery packs belonging to the second group, etc.

In a further refinement, it is provided that steps a) to c) are also carried out after the rechargeable battery units belonging to the second group have been replaced by charged rechargeable battery units. In this way, the plurality N of rechargeable battery units is dynamically assigned to the first or second group of rechargeable battery units, so that the rechargeable battery units of the rechargeable battery system are subjected to approximately the same load over the running time.

According to a second aspect, a computer program product is proposed, which can be loaded directly into the internal memory of a digital computer and comprises software code sections, with which the steps of the method described herein and its embodiments are carried out when the product is run on a computer.

According to a third aspect, a mobile system that can be operated independently of the network is proposed. The mobile system includes an accumulator system with a plurality N of removable and rechargeable battery units outside of the mobile system, a current control unit with the plurality N of individually and independently controllable current regulators, a charge determination unit that is designed to determine a current charge for each of the battery units and determine a current total charge available in the accumulator system, a computing unit, and a general load. The components mentioned are designed as described above. The computing unit is designed to carry out the steps of the method described herein and one or more configurations.

• 1 eine schematische Darstellung eines netzunabhängig betreibbaren mobilen Systems mit einem Akkumulator-System mit einer Mehrzahl N an Akkueinheiten gemäß einer Ausführung der Erfindung;
• 2 ein Diagramm, das eine erste und eine zweite Entladekurve als Vorgabe-Entladekurven für eine erste bzw. eine zweite Gruppe an Akkueinheiten illustriert;
• 3 ein Diagramm, das die beiden in 2 dargestellten Entladekurven zusammen mit den realen Entladeverläufen der Mehrzahl N an Akkueinheiten illustriert;
• 4 ein Diagramm, das die normierte Entladung jeweiliger zu der ersten und zu der zweiten Gruppe gehöriger Akkueinheiten über die Zeit und einen Wechsel der zu der zweiten Gruppe an Akkueinheiten gehörigen Akkueinheiten illustriert; und
• 5 ein Diagramm, das den zeitlichen Entladungsverlauf für alle Akkueinheiten der Mehrzahl N an Akkueinheiten eines Akkumulator-Systems illustriert.

The invention is described in more detail below using an exemplary embodiment in the drawing. Show it:

• 1 a schematic representation of a network-independent operable mobile system with a battery system with a plurality N of battery units according to an embodiment of the invention;
• 2 a diagram illustrating a first and a second discharge curve as default discharge curves for a first and a second group of rechargeable battery units;
• 3 a diagram that puts the two in 2 illustrated discharge curves illustrated together with the real discharge curves of the plurality N of battery units;
• 4 a diagram illustrating the normalized discharge of respective battery units belonging to the first and to the second group over time and a change of the battery units belonging to the second group of battery units; and
• 5 a diagram that illustrates the discharge profile over time for all rechargeable battery units of the plurality N of rechargeable battery units of a rechargeable battery system.

1 shows a schematic representation of a mobile system 1 that can be operated independently of the network. In principle, the mobile system 1 can be used for any application, such as the transport of people and/or goods, the handling of objects and/or devices, communication and/or information transfer and/or or receiving information and combinations thereof. The mobile system 1 can include any combination of different functions such as communication, computation, handling, transport and the like. In general, the mobile system can be a communication system, a computer system or a robotic system. In a specific embodiment, the mobile system 1 is a robotic assistance system, for example to support people in caring professions, a robotic assistance system to support maintenance work or a mobile transport system used for logistics. However, possible applications are not limited to the applications described here.

Mobile system 1 includes an accumulator system 10, a current control unit 20, a charge determination unit 30, a computing unit 40 and a general load 50. Mobile system 1 can also include other components, e.g. depending on the application. In the present specification, components such as to enable movement and/or manipulation of objects and/or communication are understood to be part of the general load 50 .

The accumulator system 10 comprises a plurality N of accumulator units 11-1, . . . , 11-n (n=1 to N) which can be removed and recharged outside of the mobile system 1. A rechargeable battery unit 11-1, . . . , 11-n is to be understood as meaning a rechargeable galvanic element which consists of two electrodes and an electrolyte and stores electrical energy on an electrochemical basis. A battery unit 11-1, ..., 11-n can have any number of different storage elements (secondary element or secondary cell), which are connected in a suitable manner. A series connection of several of the storage elements enables the usable electrical voltage to be increased. A parallel connection of several storage elements makes it possible to increase the usable capacity and is also suitable for higher currents. A rechargeable battery unit can also comprise a combination of storage elements connected in series and in parallel.

The plural number N is two or more, i.e. N ≥ 2. The plural number N is chosen as an even number for practical reasons, but this is not mandatory, e.g. N = 2, 4, 6, 8, 10, ...

The battery units 11-1, ..., 11-n are in an in 1 not shown housing or shaft arranged so that they can be removed by a person or an automated gripping system and replaced by battery units of the same mechanical design. In this case, rechargeable battery units with different mechanical dimensions and capacities can also be used, provided that the electrical and mechanical interface of the various rechargeable battery units 11-1, . . . , 11-n allows them to be used together.

The respective total energy contents, i.e. capacity C, of the N rechargeable battery units 11-1, . . . , 11-n can therefore also be different.

The current control unit 20 includes the same plurality N of current controllers 21-1, ..., 21-n (n=1 to N). Exactly one current controller 21-1, ..., 21-n is assigned to each of the rechargeable battery units 11-1, ..., 11-n. Each of the current controllers 21-1, ..., 21-n is set up to regulate the current output of each of the battery units 11-1, ..., 11-n assigned to it individually and independently of the other battery units 11-1, ... , 11-n to set. With the aid of a respective current controller 21-1, . For this purpose, the current controller 21-1, . . . , 21-n can be in the form of a control circuit in the form of a current-controlling switching controller.

The charge determination unit 30 is designed to determine a current charge Q _n (n=1 to N) for each of the rechargeable battery units 11-1, . . . , 11-n. A current total charge Q _tot available in the accumulator system 10 can then be determined from the entirety (sum) of the current charges Q _n .

The arithmetic unit 40 is designed to, depending on the current charge Q _n of the plurality N of battery units 11-1, ..., 11-n and the current total charge Q _tot the plurality N of current regulators 21-1, ..., 21 -n of the current control unit 20 to control. The arithmetic unit 40 makes it possible, depending on a method it executes, to load the individual current controllers 21-1, ..., 21-n with setpoint values, so that they can individually and independently control the current output of each of the rechargeable battery units 11-1, ..., set 11-n.

The general load 50 includes all consumers included in the mobile system 1, as described above. This includes, for example, electric drives for autonomous, semi-autonomous or controlled movement of the mobile system, autonomous drives for carrying out movements of mechanical gripping, holding or moving means, input and output units of a user interaction interface, lighting units, audio and/or video units and the like. The general load 50 thus represents all of the consumers present in the mobile system 1 that must be supplied with energy from the accumulator system 10 in order to operate them.

In addition to the number N of battery units 11-1, . . .

The number O of rechargeable battery units 11-1, ..., 11-n represents the number of N rechargeable battery units 11-1, ..., 11-n that are required to still have enough during a phase of exchanging discharged rechargeable battery units To be able to provide power for the operation of the mobile system 1 available. The number O of battery units 11-1, ..., 11-n represents a remaining (partial) number O of the plurality N of battery units of the invention, the remaining number O is less than N (i.e. O<N) and is at least 1. In a preferred and practical variant of the invention, the remaining number O of the plurality N of rechargeable battery units 11-1, ..., 11-n is half of the plurality N of rechargeable battery units, i.e. O½ × N, provided N is an even number is. If N is odd, the following preferably applies: O (½ × N) ± ½.

The suitable determination of the remaining number O of the plurality N of rechargeable battery units 11-1, . . . However, there are operating cases of the mobile system 1 in which more than one battery unit must remain in the battery system 10 in order to ensure reliable operation of the general load 50.

A further parameter to be defined is a residual charge R _tot required in the battery system 10 during operation of the mobile system 1 . the Residual charge R _tot is the charge that should remain in the battery system 10 during a change of part P (number P) of the battery units 11-1, ..., 11-n of the battery system 10 so that during the change the mobile system 1 can be supplied without interruption by the battery units 11-1, ..., 11-n remaining in the battery system 10. The following relationship applies between the numbers O, P and N of battery units 11-1, ..., ll-n: O + P = N or P = N - O. If necessary, it can be provided that the residual charge R _tot such it is determined that the operation provided during the change will take place with reduced performance.

In order to determine when it is necessary to change the part P of the rechargeable battery units in the rechargeable battery system 10, it must be known which current charge Q _n is in each of the rechargeable battery units 11-1, ..., 11- present in the rechargeable battery system 10. n is included. Various methods for determining the current charge in rechargeable battery units 11-1, . . . , 11-n are known from the prior art and are therefore not detailed here.

Der Übersichtlichkeit halber wird im Weiteren die im Akkumulator-System vorhandene aktuelle Gesamtladung Q_tot auf die typische Gesamtkapazität Ctot normiert, d.h. Qtot/Ctot.Advantageously, the current charges Q _n are normalized to the typical capacity C, ie the charge that can typically be stored in a rechargeable battery unit: Q _n /C. If the rechargeable battery units 11-1, . . . , 11-n have different capacities, then the typical capacity of the respective rechargeable battery unit size is normalized to C _n (n=1 to N). Unused or unoccupied battery unit connections of the battery system 10 are rated with a remaining charge of 0. As a result, the total charge Q _tot present in the system is calculated as the sum of all individual charges Q _n present, ie $Q_{tOt}={\displaystyle {\sum }_{n=1}^N{Q}_n.}$

For the sake of clarity, the current total charge Q _tot present in the accumulator system is normalized to the typical total capacity Ctot, ie Qtot/Ctot.

During the discharging process, the rechargeable battery units 11-1, ..., 11-n are divided into two groups. The classification takes place after the determination of the current charge Q _n of each of the rechargeable battery units 11-1, ..., 11-n with the aid of the charge determination unit 30.

The number O of the plurality _N of rechargeable battery units 11-1, are. The remaining number P of the plurality N of rechargeable battery units 11-1, ..., 11-n is assigned to a second group Grp_II of rechargeable battery units, with those P rechargeable battery units in the second group having the least current charge Q _n of the plurality N of rechargeable battery units 11 -1, ..., 11-n are included. The relation between the remaining number O, the number P and the plurality N is as stated above: P = N - O. If, as also described above, O in is chosen as half of the plurality N, it follows that the number P equals half of the plurality N (where N is assumed to be even in this formulation).

In a next step, the total residual charge R _tot is determined as the sum of all residual charges of all rechargeable battery units 11-1 _, . If the determined current residual charge reaches the predefined residual charge value R _tot , information can be output to a user or a station, for example, that some of the discharged rechargeable battery units 11-1, . . . , 11-n must be replaced. If the exchange takes place in an automated manner, the mobile system 1 can also drive to a corresponding station.

The method described enables a simultaneous and defined uneven (in terms of power consumption) discharge of the plurality N of battery units 11-1, ..., 11-n of the battery system 10, so that on the one hand the longest possible service life before changing battery units and on the other hand, enough energy reserve is guaranteed while changing the battery units.

It should be noted that in this description the term "charge" is used as a measure for the "level" of the battery units. Alternatively, the process can of course also be implemented with the energy contained as a "level gauge".

Gentle discharging and a high energy yield are achieved in that none of the N rechargeable battery units 11-1, ..., 11-n remains unused in the rechargeable battery system, but always all rechargeable battery units 11-1, ..., 11-n be discharged from both the first and the second group Grp_I, Grp_II with a different load share for each of the two groups. The first and the second group Grp_I, Grp_II are discharged at the same time, the battery units belonging to the second group Grp_II being discharged more quickly than the battery units belonging to the first group Grp_I, so that during the changeover of the battery units of the more quickly discharged group (second group Grp_II ) ensure the supply of the general load 50 by the battery units of the first group Grp_I. After changing the battery units of the second group Grp_II, which initially discharged more quickly, their fully charged batteries stop ensure the supply of the general load 50, so that the battery units of the first group Grp_I can be changed. This procedure is then repeated in a cyclic manner.

This will be like this in 2 is shown schematically, two sections defined discharge curves generated from straight sections that have the following properties. 2 shows a diagram that illustrates a first and a second discharge curve y1, y2 for the first and the second group Grp_I, Grp_II of rechargeable battery units. The discharge curves y1 defined in sections for the rechargeable battery units of the first group Grp_I and y2 for the rechargeable battery units of the second group Grp_II are plotted against the typical normalized total capacity Q _tot /C _tot . y1 and y2 represent the remaining charge in percent (%).

The discharge curve y1 for the O battery units of the first group Grp_I is defined by two straight lines. The first line segment is 1 (100%) at Q _tot /C _tot = 1 (100%) and falls linearly to R _tot /C _tot /P .· N at Qtot/Ctot = R _tot /C _tot .

For values of Qtot/Ctot > R _tot /C _tot , the second line segment falls more steeply, so that it falls to 0 (0%) at Qtot/Ctot = 0 (0%). This results in the following definition for the O battery units of the first group Grp_I: $$y_1\left(Q_{tOt}\right)=\{\begin{array}{c}\frac{Q_{tOt}-R_{tOt}}{C_{tOt}-R_{tOt}}\cdot \left(1-\frac{R_{tOt}\cdot N}{C_{tOt}\cdot P}\right)+\frac{R_{tOt}\cdot N}{C_{tOt}\cdot P}ƒ\ddot{\text{and}}\mathrm{right}{Q}_{tOt}\ge R_{tOt}\\ \frac{Q_{tOt}}{C_{tOt}}\cdot \frac{N}{P}ƒ\ddot{\text{and}}\mathrm{right}{Q}_{tOt}<R_{tOt}\end{array}$$

The discharge curve y2 for the P battery units of the second group Grp_II is defined by 1 (100%) at Qtot/Ctot = 1 (100%) and a linear drop to 0 (0%) at Q _tot /C _tot = R _tot /C _dead . For values of Qtot/Ctot > R _tot /C _tot it remains 0 (0%). For the P rechargeable battery units of the second group Grp_II, this results in the following definition for the discharge curve y depending on the current total charge Q _tot in the system: $$y_2\left(Q_{tOt}\right)=\{\begin{array}{c}\frac{Q_{tOt}-R_{tOt}}{C_{tOt}-R_{tOt}}ƒ\ddot{\text{and}}\mathrm{right}{Q}_{tOt}\ge R_{tO\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="DE102020212769A1\_0007.png,DE102020212769A1\_0008.png"\; state="\{\{state\}\}">t</figure-callout>}}\\ 0ƒ\ddot{\text{and}}\mathrm{right}\frac{Q_{tOt}}{C_{tOt}}<\frac{R_{tOt}}{C_{tOt}}\end{array}$$

In the 2 The exemplary discharge curves y1, y2 shown represent discharge specifications for the first and second group Grp_I, Grp_II of rechargeable battery units 11-1, ..., 11-n, with the specified remaining charge R _tot being 15%, the majority N=6 and the numbers O = P = 3 were chosen.

The control algorithm described below ensures that the O battery units of the first group Grp_I, which initially include the highest current charge Q _n of the plurality N of battery units 11-1, ..., 11-n, when discharging the discharge curve y1 and the Units of the second group Grp_II of battery units follow the discharge curve y2.

For this purpose, the relative state of charge of each battery unit Q _n /C _n is compared with the discharge curve y1 or y2 responsible for it - depending on the state of charge - and a load component An (n = 1 to N) via a proportional component k, as well as a control variable limitation to a value range between Amine and Amax determined according to: $$A_n\{\begin{array}{c}min\left(max\left(\left(\frac{Q_n}{C_n}-y_{1.2}\right)\cdot k;A_{min}\right);A_{max}\right)f\ddot{\mathrm{and}}\mathrm{right}{Q}_n>0\\ 0ƒ\ddot{\text{and}}\mathrm{right}{Q}_n=0\end{array}$$

Limiting the manipulated variable to the value range between Amin and Amax makes it possible to limit fluctuations around the specified discharge curve. The command value limit also serves to ensure that the battery units are not unintentionally recharged as a result of the specifications determined. Furthermore, the limitation of the manipulated variable makes it possible for some charge to be taken from almost empty battery units, which results in a better utilization of capacity.

Completely empty battery units or battery units that are not plugged into the battery system 10 receive a load proportion An=0.

The proportional component k is determined empirically. The proportional component k results from the controller principle. A value of k=10 has proven to be useful in tests. The manipulated variable limit Amin is selected to be greater than 0. Values less than 0 would result in the controller triggering charge transfer between the battery units 11-1, ..., 11-n. Smaller values for Amin in the order of [0.1...1] lead to a slight deviation from ideal behavior, ensure shared use of almost empty battery units and thus improve the overall running time of the battery system 10. A value in the range [1 ... 10] for Amax gave good values in tests and is determined empirically.

With the load shares An and the required total power Ltot, the current to be drawn from each battery unit 11-1, ..., 11-n or the power to be drawn L _n (n=1 to N) can be defined in that the required Total power L _tot is multiplied by the ratio of the respective load share A _n to the sum of all load shares according to: $$L_n=L_{tOt}\cdot \frac{A_n}{{\displaystyle \sum {}_{i=1...N}{A}_i}}$$

3 shows the discharge process of the example N = 6 battery units (“unit 1”, “unit 2”, “unit 3”, “unit 4”, “unit 5”, “unit 6”) with a proportional component k = 10, amine = 0 ,1 and Amax = 2, where again O = P = 3 and R _tot = 15% are chosen. It is easy to see that three of the six battery units are divided into the first or second group Grp_I, Grp_II due to their slightly different charges, some of which are above and some below the nominal capacity of a battery unit, and each of the battery units is then assigned their charge approaches the associated discharge specification y1 or y2. In this exemplary embodiment, the curves marked “unit 1”, “unit 2”, “unit 3” belong to the O=3 rechargeable battery units of the first group Grp_I (with a higher current charge). The trajectories labeled "Unit 4", "Unit 5", "Unit 6" belong to the P = 3 battery units of the second group Grp_II (with low current charge). The three battery units with the low charge ("Unit 4", "Unit 5", "Unit 6"), ie battery units of the second group Grp_II, become empty first and exactly when the other three battery units ("Unit 1", " Unit 2", "Unit 3"), ie battery units of the first group Grp_I) still contain 30% of their charge, which corresponds to a total charge of 15% in the battery system 10.

If one or more of the battery units of the second group Grp_II ("Unit 4", "Unit 5", "Unit 6") are changed, i.e. replaced by fully charged battery units, the algorithm automatically adapts to the new conditions.

4 shows an example of the process after changing the battery units of the second group Grp_II ("Unit 4", "Unit 5", "Unit 6"). It should be noted that 4 has a different scaling of the discharge course for the sake of clarity. Here, the horizontal axis does not show the total charge, but the qualitative course over time of the discharge with a constant discharge current. Again, it is easy to see that the battery units of the second group Grp_II ("Unit 4", "Unit 5", "Unit 6") of the second group Grp_II on the battery unit are discharged faster than the battery units of the first group Grp_I ("Unit 1 ", "Unit 2", "Unit 3") representing battery units of the first group Grp_I of battery units.

If the method is to ensure that after the exchange of the empty battery units of the battery units belonging to the second group Grp_II, the not yet completely empty battery units of the first group Grp_I of battery units are then discharged more quickly so that they can then also be exchanged immediately the distance between amine and Amax can be reduced and, if necessary, the factor k can be increased.

5 shows the exchange of all six battery units (“unit 1”, “unit 2”, “unit 3”, “unit 4”, “unit 5”, “unit 6”) in quick succession with a factor k = 100, A _min = 1 and A _max = 2, whereby the following still applies: The curves marked with "Unit 1", "Unit 2", "Unit 3" belong to the O = 3 battery units of the first group Grp_I (with a higher current charge). The trajectories labeled "Unit 4", "Unit 5", "Unit 6" belong to the P = 3 battery units of the second group Grp_II (with low current charge).

The assignment of respective rechargeable battery units to the first group Grp_I of rechargeable battery units or the second group Grp_II of rechargeable battery units after determining the respective current charges Q _n takes place initially when the plurality N of rechargeable battery units is brought into the rechargeable battery system 10 fully charged. Furthermore, the steps mentioned are carried out after each replacement of the rechargeable battery units belonging to the second group Grp_II with charged rechargeable battery units or generally carried out after each replacement of at least one rechargeable battery unit.

In a simpler embodiment, the described method is also suitable for exclusively discharging rechargeable battery units of the second group Grp_II and protecting the rechargeable battery units belonging to the first group Grp_I until the rechargeable battery units from the second group Grp_II are completely discharged. Information is then generated that the rechargeable battery units of the second group Grp_II can now be exchanged, but do not have to. From this point on, only the battery units of the first group Grp_I are discharged. As soon as the total charge falls below the specified residual charge R _tot , warning information is issued that the empty battery units now have to be replaced if uninterrupted operation is to be ensured.

An advantage of the simpler embodiment is that batteries that are ready to be replaced are available as early as possible. In addition, this variant is particularly simple. One disadvantage is that the load is always distributed unevenly across the battery units, which means that a lower energy yield has to be accepted, which results from the well-known Peukert effect and increased internal resistance. In addition, those battery units that have a slightly above-average capacity Protected, since fuller battery units are initially not discharged and even after replacing the empty units with the fuller units, charge is only taken from the units of the other group with the lower capacity. As a result, the battery units with the highest capacity initially remain unused in the system and possibly for a longer period of time.

Reference List

1

mobile system

10

accumulator system

11-1, ..., 11-n

battery units

20

current control unit

21-1, ..., 21-n

current regulator

30

charge determination unit

40

unit of account

50

load

Grp_I

first group of battery packs

Grp_II

second group of battery units

Qn

current charge

red

residual charge

Claims (12)

Method for the uninterrupted operation of a mobile system (1) that is operated independently of the mains, the mobile system (1) comprising: - a rechargeable battery system (10) with a plurality N of removable rechargeable battery units (11-1, .. ., 11-n); - a current control unit (20) with the plurality N of current regulators (21-1, ..., 21-n), each of the rechargeable battery units (11-1, ..., 11-n) having a current regulator (21-1, ..., 21-n) is assigned to the power output of each of the battery units (11-1, ..., 11-n) individually and independently of the other battery units (11-1, ..., 11-n) to discontinue; - a charge determination unit (30) which is designed to determine a current charge (Q _n ) and a current total charge (Q n ) available in the battery system (10) for each of the rechargeable battery units (11-1, ..., to determine Qtot); - A computing unit (40) which is designed to, depending on the current charge (Q _n ) of the plurality N of rechargeable battery units (11-1, ..., 11-n) and the current total charge (Qtot) the plurality N to control current controllers (21-1, ..., 21-n) of the current control unit (20); and - a general load (50); the method comprising the following steps: a) determining the current charge (Q _n ) of each of the rechargeable battery units (11-1, ..., 11-n); b) assigning a number O of the plurality N of battery units (11-1, ..., 11-n) to a first group (Grp_I) of battery units, the battery units with the highest current charge being in the first group (Grp I). (Q _n ) of the plurality N of battery units (11-1, ..., 11-n); c) assigning the remaining number P of the plurality N of battery units (11-1, ..., 11-n) to a second group (Grp_II) of battery units, the second group (Grp_II) containing those battery units with the least current charge (Q _n ) of the plurality N of rechargeable battery units (11-1, ..., 11-n) and where: P = N - Q; d) Discharging the rechargeable battery units (11-1, ..., 11-n) until a predetermined residual charge (Rtot) is reached, the residual charge (Rtot) being the charge that remains during a change to the second group (Grp_II) battery units (11-1, ..., 11-n) belonging to discharged battery units are required by charged battery units in order to supply the general load (50) without interruption during the change; e) Supplying the general load (50) from the battery units (11-1, ..., 11-n) belonging to the first group (Grp_I) of battery units until the replacement of the battery units belonging to the second group (Grp_II) of discharged battery units Battery units (11-1, ..., 11-n) is completed by charged battery units. procedure after claim 1 , characterized in that to supply the general load (50) until a predetermined residual charge (Rtot) is reached, the battery units of the first group (Grp I) and the second group (Grp_II) belonging battery units (11-1,. .., 11-n) are discharged. procedure after claim 1 or 2 , characterized in that the battery units of the first group (Grp_I) and the battery units of the second group (Grp_II) associated battery units (11-1, ..., 11-n) with a different load share (A _n ) discharged will. Method according to one of the preceding claims, characterized in that the battery units belonging to the first group (Grp_I) battery units (11-1, ..., 11-n) are discharged with a load component which is smaller than the load component of the the second group (Grp_II) Method according to one of the preceding claims, characterized in that the battery units (11-1, ..., 11-n) belonging to the second group (Grp_II) of battery units are completely discharged. Method according to one of the preceding claims, characterized in that the battery units (11-1, ..., 11-n) belonging to the first group (Grp_I) of battery units are completely discharged after the change. Method according to one of the preceding claims, characterized in that the discharge of the rechargeable battery units (11-1, ..., 11-n) belonging to the first group (Grp_I) is controlled by the respective current regulator (21-1, ..., 21 -n) takes place in such a way that the respective current draw follows a predetermined first discharge curve (K_I) for the first group (Grp_I) of battery units, in particular with two straight line sections, and the discharge of the battery units (11-1 , ..., 11-n) by the respective current controller (21-1, ..., 21-n) takes place in such a way that the respective current draw of a predetermined second discharge curve (K_II) for the second group (Grp_II) of battery units, in particular with a straight line segment, follows. Method according to one of the preceding claims, characterized in that steps a) to c) are initially carried out when the plurality N of rechargeable battery units (11-1, ..., 11-n) is fully charged in each case. Method according to one of the preceding claims, characterized in that steps a) to c) are carried out dynamically, in particular after changing the rechargeable battery units (11-1, ..., 11-n) is performed by charged battery units. A computer program product loadable directly into the internal memory of a digital computer, comprising software code portions which, when run on a computer, perform the steps of any preceding claim. Mobile system (1), comprising: - a battery system (10) with a plurality N of removable and rechargeable battery units (11-1, ..., 11-n) outside of the mobile system; - a current control unit (20) with the plurality N of current regulators (21-1, ..., 21-n), each of the rechargeable battery units (11-1, ..., 11-n) having a current regulator (21-1, ..., 21-n) is assigned to the power output of each of the battery units (11-1, ..., 11-n) individually and independently of the other battery units (11-1, ..., 11-n) to discontinue; - a charge determination unit (30) which is designed to determine a current charge (Q _n ) and a current total charge (Q n ) available in the battery system (10) for each of the rechargeable battery units (11-1, ..., to determine Qtot); - A computing unit (40) which is designed to, depending on the current charge (Q _n ) of the plurality N of rechargeable battery units (11-1, ..., 11-n) and the current total charge (Qtot) the plurality N to control current controllers (21-1, ..., 21-n) of the current control unit (20); and - a general load (50); wherein the computing unit (40) is designed to carry out the following steps: a) determining the current charge (Q _n ) of each of the rechargeable battery units (11-1, ..., 11-n); b) assigning a number O of the plurality N of battery units (11-1, ..., 11-n) to a first group (Grp_I) of battery units, the battery units with the highest current charge being in the first group (Grp I). (Q _n ) of the plurality N of battery units (11-1, ..., 11-n); c) assigning the remaining number P of the plurality N of battery units (11-1, ..., 11-n) to a second group (Grp_II) of battery units, the second group (Grp_II) containing those battery units with the least current charge (Q _n ) of the plurality N of rechargeable battery units (11-1, ..., 11-n) and where: P = N - Q; d) Discharging the rechargeable battery units (11-1, ..., 11-n) until a predetermined residual charge (Rtot) is reached, the residual charge (Rtot) being the charge that remains during a change to the second group (Grp_II) battery units (11-1, ..., 11-n) belonging to discharged battery units are required by charged battery units in order to supply the general load (50) without interruption during the change; e) Supplying the general load (50) from the battery units (11-1, ..., 11-n) belonging to the first group (Grp_I) of battery units until the replacement of the battery units belonging to the second group (Grp_II) of discharged battery units Battery units (11-1, ..., 11-n) is completed by charged battery units. device after claim 11 , characterized in that the computing unit (40) for carrying out in one of claims 2 until 9 included steps is formed.

Images