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

Abstract

Method for the uninterrupted operation of a network-independent mobile system (1), wherein the mobile system (1) comprises: - an accumulator system (10) with a plurality N of removable battery units (11-1,..., 11-n) that can be recharged outside the mobile system; - a current control unit (20) with the plurality N of current regulators (21-1,..., 21-n), wherein each of the battery units (11-1,..., 11-n) is assigned a current regulator (21-1,..., 21-n) in order to adjust the current output of each of the battery units (11-1,..., 11-n) individually and independently of the other battery units (11-1,..., 11-n); - a charge determination unit (30) which is designed to determine a current charge (Q n ) and a current total charge (Q tot ) to determine; - a computing unit (40) which is designed to calculate, 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 ) to control the plurality N of current controllers (21-1,..., 21-n) of the current control unit (20); and - a general load (50); the method comprising the following steps: a) Determine the current charge (Q n ) each of the 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, wherein in the first group (Grp_I) the battery units with the highest current charge (Q n ) of the plurality N of battery units (11-1,..., 11-n) are included; 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, wherein in the second group (Grp_II) those battery units with the least current charge (Q n ) of the plurality N of battery units (11-1,..., 11-n) and where: P = N - O; d) Discharging the battery units (11-1,..., 11-n) until a specified residual charge (R tot ), where the residual charge (R tot ) is the charge required during a replacement of the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) of discharged battery units by charged battery units in order to supply the general load (50) without interruption during the replacement; 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 (11-1,..., 11-n) belonging to the second group (Grp_II) of discharged battery units by charged battery units is completed.

Description

[0001] The invention relates to a method for the uninterrupted operation of a network-independent mobile system and to a network-independent mobile system.

[0002] Mobile electrical systems, such as communications, computer, or robotic systems, are equipped with power supply units that provide a network-independent (wireless) power supply. To ensure continuous network-independent operation of the mobile system, these power supply units must be recharged when they are discharged, which requires the mobile system to be paused. If the mobile system has a power supply unit swap system with at least two battery units, the mobile system can continue to operate with the other battery unit while one battery unit is being swapped.

[0003] In such power supply units designed as swappable systems, all battery units in the power supply unit are usually discharged simultaneously and evenly. This means that all battery units in the power supply unit become empty at approximately the same time. To ensure uninterrupted operation of the mobile system, the battery units must be swapped for fully charged ones before they are completely discharged. During the swap or swap process, the mobile system is supplied with power from the other battery units in the mobile system that have sufficient charge. However, since battery units must always be swapped at a time when the replaced or swapped battery units still have a charge, this means a reduction in the mobile system's runtime between swapping or swapping battery units.

[0004] In another variant, the battery units of the power supply unit could be discharged simultaneously, in an undefined independent and uneven manner, which, however, makes a deterministic replacement of the respective battery units difficult.

[0005] Additionally, the option to switch between individual battery units could be provided to discharge them in a defined manner and not simultaneously. However, this also has a negative impact on the operating time of the mobile system, as the system power is drawn from individual battery units instead of all of the power supply unit's batteries. This leads to a lower energy yield due to the well-known Peukert effect, higher losses due to the internal resistance of each battery unit, and an earlier end of discharge due to the internal resistance-related earlier reaching of the end-of-charge voltage due to the higher discharge currents.

[0006] US 5 959 368 A discloses a power supply device comprising a plurality of batteries and a plurality of power supply sections for connection to loads, wherein a plurality of switches connects these batteries to these power supply sections, respectively. The power supply device further includes a control mechanism that controls the opening and closing operations of the switches. When one of the switches in one of the power supply sections is turned on, the control mechanism executes control such that the other switches are turned off. The control mechanism further controls each of the switches based on the remaining capacity of each battery and the load state of each part of the power supply. In the event of an excessive load current being drawn from one battery, a selection M of batteries is determined. This is intended to distribute the load currents.The number M represents a subset of the total number of batteries. Load balancing occurs within the M batteries.

[0007] US 2005 / 0 121 979 A1 discloses battery packs comprising a plurality of rechargeable batteries connected in series to obtain a voltage required by a load device. The battery packs are removably housed in a housing and connected in parallel. Each of their outputs is set to a predetermined voltage by a discharge control section. The battery packs are connected to a power source line of the load device. Each battery pack is connected via an information transmission line to a control section for the power source, which controls the charging and discharging of the batteries and determines their service life. A battery pack is only replaced when a life cycle criterion, which is determined using an impedance measurement, is met. Thus, only the battery pack determined for the service life is replaced.

[0008] EP 2 441 632 B1 discloses a power supply system for a hybrid vehicle, comprising a main energy storage device and a plurality of selectively used sub-storage devices. When the SOC of each energy storage device drops to an SOC control target, a driving mode changes. Differential discharge of the sub-storage devices may be provided during discharge allocation.

[0009] It is an object of the invention to provide a method for the uninterrupted operation of a network-independently operated mobile system and a network-independently operated mobile system which is functionally improved and enables optimized energy utilization of the energy available in its energy supply unit.

[0010] 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 embodiments emerge from the dependent claims.

[0011] 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 communications system, a computer system, or a robotic system. The mobile system can also comprise functions of communications, computer, and robotic components in any combination. For example, the mobile system is an assistance robotics system or a mobile transport system used for logistics.

[0012] The mobile system comprises an accumulator system with a plurality N of removable battery units that can be recharged outside the mobile system. A battery unit (also referred to as an accumulator or battery) is a rechargeable galvanic element consisting of two electrodes and an electrolyte, which stores electrical energy on an electrochemical basis. A battery unit can comprise any number of different storage elements (also referred to as secondary elements or secondary cells), which are suitably connected in series and / or parallel. Connecting several storage elements in series enables the usable electrical voltage to be increased. Connecting several storage elements in parallel enables the usable capacity to be increased and is suitable for higher currents.Both circuit variants allow for a specified total energy content, specified in watt-hours (Wh), of the respective battery unit. The plural N is two or more. The battery units are arranged in the battery system, e.g., in a housing, in such a way that they can be removed and reinserted from the battery system, e.g., manually or using an automated gripping unit. The battery units are not recharged within the mobile system, but rather at an external charger.

[0013] The mobile system further comprises a current control unit with a plurality of N current regulators. Each of the battery units is assigned a current regulator to adjust the current output of each of the battery units individually and independently of the other battery units. A respective current regulator can, for example, be designed as a current-regulating switching regulator. This compensates for the voltage differences between the voltage of the connected battery unit and the power supply bus and, based on an external input, can generate a current flow between the battery unit and the power supply bus with a defined direction and strength.

[0014] The mobile system further comprises a charge determination unit configured 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 battery system is determined from the sum of all current charges of each of the plurality N of battery units.

[0015] A computing unit of the mobile system is configured to control the plurality of N current regulators of the current control unit depending on the current charge of the plurality of N battery units and the current total charge. The computing unit is thus configured to apply setpoints to the individual current regulators depending on a method it executes, so that they can individually and independently adjust the current output of each of the battery units.

[0016] 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 devices, 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 that are supplied with energy from the accumulator system for their operation. The load, consisting of one or more consumers, is connected to the power regulators via a common power supply bus.

[0017] The procedure includes the following steps: In step a) the current charge of each of the battery units is determined. In step b), a number O of the plurality N of battery units is assigned to a first group of battery units. The number O of the plurality N of battery units thus represents a partial number of the plurality N of battery units. The first group of battery units contains the battery units with the highest current charge of the plurality N of battery units. The number O of the plurality N can, in principle, be chosen arbitrarily. It is expedient if the number O is approximately half of the plurality N, i.e. O ≈ 0.5 N. In step c), the remaining number P of the plurality N of battery units is assigned to a second group of battery units, wherein the second group contains those battery units with the lowest current charge of the plurality N of battery units. The relationship between the number O, the number P, and the plurality N is as follows: P = N - O. If the number O is approximately half of the plurality N, i.e., O ≈ 0.5 N, then the number P is also approximately half of the plurality N, i.e., P ≈ 0.5 N. In step d), the battery units are discharged until a predetermined residual charge is reached. The residual charge is the charge required during a replacement of the battery units belonging to the second group of discharged battery units with charged battery units in order to supply the general load without interruption during the replacement. This means that the residual charge must be provided by the battery units belonging to the first group. 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 by charged battery units is completed.

[0018] The method according to the invention enables continuous operation of the mains-independent mobile system. This ensures gentle discharging and optimal energy yield of the battery units of the battery system. In particular, the method ensures that no battery units remain unused in the battery system, but rather that all battery units from the first and second groups can be discharged - with the exception of the time required to replace the battery units belonging to the second group of discharged battery units. After the initially discharged battery units of the second group have been replaced, 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 replaced when they are discharged.

[0019] In one expedient embodiment, it is provided that, in order to supply the general load, the battery units of the battery units belonging to the first group and the battery units belonging to the second group are discharged until a predetermined residual charge is reached. In other words, according to this embodiment, all battery units are always discharged to supply the general load. When the predetermined residual charge is reached, which initiates a change of the battery units of the battery units belonging to the second group, supply is then carried out by the battery units belonging to the first group of battery units while the discharged battery units of the battery units belonging to the second group are changed. This ensures that no battery units remain unused in the mobile system or its battery system.

[0020] 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 share. By doing this, the battery units of both groups, i.e. the first and the second group, are discharged simultaneously. However, the battery units of one group, namely the battery units belonging to the first group, are discharged more slowly than the battery units of the other group, namely the battery units belonging to the second group. While the faster discharged group (second group) is being changed, the supply of the mobile system is ensured by the other (first) group. After the initially faster discharged battery units have been changed, their fully charged battery units ensure the supply of the system, so that the battery units of the other group can be changed.

[0021] A further advantageous embodiment provides that the battery units belonging to the first group are discharged with a load share that is lower than the load share of the battery units belonging to the second group. Discharging the battery units belonging to the second group with a higher load share thus results in faster discharging than the battery units belonging to the first group.

[0022] A further advantageous embodiment provides that the battery units belonging to the second group of battery units are completely discharged. This allows the energy stored in the second group of battery units to be fully utilized. During the replacement 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.

[0023] It is also advisable to fully discharge the battery units belonging to the first group of battery units after replacing the battery units belonging to the second group of battery units. This results in maximum energy yield from the energy content provided by the battery system.

[0024] A further expedient embodiment provides that the discharge of the battery units belonging to the first group is carried out 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 discharge of the battery units belonging to the second group is carried out by the respective current regulators in such a way that the respective current draw follows a predetermined second discharge curve for the second group of battery units. This can be achieved by comparing the relative charge state of the respective battery units with the applicable discharge curve.The first and second discharge curves therefore represent target discharge curves, with the respective current regulators regulating in such a way that they individually and independently of the other battery units set the required current output in order to achieve the best possible match between the actual discharge curve and the predetermined discharge curve. In particular, the first discharge curve comprises two or more straight line segments. The second discharge curve expediently comprises a single straight line segment. The intersection point of the two straight line segments of the first discharge curve expediently coincides with the reaching of the residual charge, at which point the single straight line segment of the second discharge curve has dropped to 0%, i.e. when the battery units of the battery units belonging to the second group are discharged.

[0025] A further advantageous embodiment provides that steps a) to c) are initially performed when the plurality N of battery units are each fully charged. Steps d) and e), however, are performed iteratively to ensure continuous operation of the mobile system by successively changing the battery units belonging to the two groups: changing the battery units belonging to the second group, followed by changing the battery units belonging to the first group, followed by changing the battery units belonging to the second group, etc.

[0026] In a further embodiment, steps a) to c) are also performed after the battery units belonging to the second group have been replaced by charged battery units. In this way, the plurality N of battery units is dynamically assigned to the first or second group of battery units, so that the battery units of the accumulator system are subject to approximately the same load over their operating time.

[0027] 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 and its embodiments described herein are carried out when the product is run on a computer.

[0028] According to a third aspect, a mobile system that can be operated independently of a mains supply is proposed. The mobile system comprises an accumulator system with a plurality N of removable battery units that can be recharged outside 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 and a current total charge available in the accumulator system for each of the battery units, a computing unit, and a general load. The aforementioned components are designed as described above. The computing unit is designed to carry out the steps of the method described herein and one or more embodiments.

[0029] The invention is described in more detail below using an exemplary embodiment in the drawing. In the drawings: Fig. 1 is a schematic representation of a mobile system operable independently of the mains, comprising an accumulator system with a plurality N of accumulator units according to an embodiment of the invention; Fig. 2 is a diagram illustrating first and second discharge curves as default discharge curves for a first and second group of battery units, respectively; Fig. 3 a diagram showing the two Fig. 2 illustrated discharge curves together with the actual discharge profiles of the plurality N of battery units; Fig. 4 a diagram illustrating the normalized discharge of respective battery units belonging to the first and second groups over time and a change of the battery units belonging to the second group of battery units; and Fig. 5 a diagram illustrating the temporal discharge curve for all battery units of the plurality N of battery units of a battery system.

[0030] Fig. 1 shows a schematic representation of a network-independently operable mobile system 1. The mobile system 1 can in principle serve any desired application, such as the transport of people and / or goods, the handling of objects and / or devices, communication and / or information transfer and / or information receipt, and combinations thereof. The mobile system 1 can comprise any desired combination of different functions, such as communication, computing, handling, transport, and the like. In general, the mobile system can be a communication system, a computer system, or a robot system. In a specific embodiment, the mobile system 1 is an assistance robotics system, for example for supporting people in caregiving professions, an assistance robotics system for supporting maintenance work, or a mobile transport system used for logistics.However, possible applications are not limited to those described here.

[0031] The mobile system 1 comprises a battery system 10, a current control unit 20, a charge determination unit 30, a computing unit 40, and a general load 50. The mobile system 1 may also comprise other components, e.g., depending on the application. In the present description, components such as those enabling movement and / or handling of objects and / or communication are understood as components of the general load 50.

[0032] The accumulator system 10 comprises a plurality N of removable battery units 11-1, ..., 11-n (n = 1 to N) that can be recharged outside of the mobile system 1. A battery unit 11-1, ..., 11-n is understood to be a rechargeable galvanic element consisting of two electrodes and an electrolyte, and stores electrical energy on an electrochemical basis. A battery unit 11-1, ..., 11-n can comprise any number of different storage elements (secondary element or secondary cell) that are suitably interconnected. Connecting several of the storage elements in series enables the usable electrical voltage to be increased. Connecting several storage elements in parallel enables the usable capacity to be increased and is also suitable for higher currents. A battery unit can also comprise a combination of storage elements connected in series and in parallel.

[0033] The plurality N is two or more, ie N ≥ 2. The plurality N is chosen as an even number for practical reasons, although this is not mandatory, e.g. N = 2, 4, 6, 8, 10, ...

[0034] The battery units 11-1, ..., 11-n are in a Fig. 1, so that they can be removed by a person or an automated gripping system and replaced with battery units of the same mechanical design. Battery units with different mechanical dimensions and capacities can also be used, provided the electrical and mechanical interface of the various battery units 11-1, ..., 11-n allows for shared use.

[0035] This means that the respective total energy contents, ie capacity C, of ​​the N battery units 11-1, ..., 11-n can also be different.

[0036] The current control unit 20 comprises the same plurality N of current regulators 21-1, ..., 21-n (n = 1 to N). Each of the battery units 11-1, ..., 11-n is assigned exactly one current regulator 21-1, ..., 21-n. Each of the current regulators 21-1, ..., 21-n is configured to adjust 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. With the aid of a respective current regulator 21-1, ..., 21-n, it is thus possible to individually adjust the current or power output of each of the battery units 11-1, ..., 11-n. For this purpose, the current regulator 21-1, ..., 21-n can be designed, for example, as a control circuit in the form of a current-regulating switching regulator.

[0037] The charge determination unit 30 is designed to determine a current charge Q for each of the battery units 11-1, ..., 11-n n (n = 1 to N). From the total (sum) of the current charges Q n, then a current total charge Q available in the accumulator system 10 can be tot be determined.

[0038] The computing unit 40 is designed to, depending on the current charge Q n the plurality N of battery units 11-1, ..., 11-n and the current total charge Q tot to control the plurality N of current regulators 21-1, ..., 21-n of the current control unit 20. The computing unit 40 makes it possible, depending on a method executed by it, to apply setpoints to the individual current regulators 21-1, ..., 21-n so that they individually and independently adjust the current output of each of the battery units 11-1, ..., 11-n in a predetermined manner.

[0039] The general load 50 comprises all consumers contained in the mobile system 1, as described above. This includes, for example, electrical drives for the autonomous, semi-autonomous, or controlled movement of the mobile system, autonomous drives 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 50 thus represents all consumers present in the mobile system 1 that must be supplied with energy from the accumulator system 10 for their operation.

[0040] For uninterrupted operation of the mains-independent mobile system 1, the following parameters must be defined in addition to the number N of battery units 11-1, ..., 11-n contained in the battery system 10.

[0041] The number O of battery units 11-1, ..., 11-n represents the number N of battery units 11-1, ..., 11-n which are required in order to be able to provide sufficient power for the operation of the mobile system 1 during a phase of exchanging discharged battery units. 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 amounts to at least 1. In a preferred and practical variant of the invention, the remaining number O of the plurality N of battery units 11-1, ..., 11-n amounts to half of the plurality N of battery units, i.e. O ½ × N, provided N is an even number. If N is an odd number, the following preferably applies: O (½ × N) ± ½.

[0042] The appropriate determination of the remaining number O of the plurality N of battery units 11-1, ..., 11-n is necessary because an arbitrarily high power cannot be drawn from a single battery unit. However, there are operating cases of the mobile system 1 in which more than one battery unit must remain in the battery system 10 to ensure reliable operation of the general load 50.

[0043] Another parameter to be defined is a residual charge R required in the accumulator system 10 during operation of the mobile system 1 tot . The residual charge R totis the charge that should remain in the accumulator system 10 during a replacement of a part P (number P) of the accumulator units 11-1, ..., 11-n of the accumulator system 10, so that during the replacement the mobile system 1 can be supplied without interruption by the accumulator units 11-1, ..., 11-n remaining in the accumulator system 10. The following relationship applies between the numbers O, P and N of accumulator units 11-1, ..., 11-n: O + P = N or P = N - O. If necessary, it can be provided that the residual charge R tot is set in such a way that the operation provided during the changeover takes place with reduced performance.

[0044] To determine when a replacement of part P of the battery units of the battery system 10 is necessary, the current charge Q must be known. ncontained in each of the battery units 11-1, ..., 11-n present in the battery system 10. Various methods for determining the current charge in battery units 11-1, ..., 11-n are known from the prior art and will therefore not be explained in more detail here.

[0045] Advantageously, the current charges Q n standardized to the typical capacity C, i.e. the charge that can typically be stored in a battery unit: Q n / C. If the battery units 11-1, ..., 11-n have different capacities, the typical capacity of the respective battery unit size is set to C n (n = 1 to N). Unused or unoccupied battery unit terminals of the battery system 10 are rated with a residual charge of 0. This means that the total charge Q present in the system tot as the sum of all existing individual charges Q n calculated, i.e. Qtot=∑n=1NQn. For the sake of clarity, the current total charge Q in the accumulator system is shown below. tot to the typical total capacity C tot normalized, i.e. Q tot / C tot .

[0046] During the discharge process, the battery units 11-1, ..., 11-n are divided into two groups. The classification is based on the determination of the current charge Q n each of the battery units 11-1, ..., 11-n using the charge determination unit 30.

[0047] The number O of the plurality N of battery units 11-1, ..., 11-n is assigned to a first group Grp_I of battery units, wherein in the first group Grp_I the O battery units with the highest current charge Q nof the plurality N of battery units are included. The remaining number P of the plurality N of battery units 11-1, ..., 11-n is assigned to a second group Grp_II of battery units, wherein in the second group those P battery units with the least current charge Q n the majority N of the battery units 11-1, ..., 11-n are included. The relationship between the remaining number O, the number P, and the plurality N is as described above: P = N - O. If, as also described above, O is chosen as half of the plurality N, it follows that the number P also corresponds to half of the plurality N (wherein an even number of N is assumed in this formulation).

[0048] In a next step, the total residual charge R tot as the sum of all residual charges of all battery units 11-1, ..., 11-n of the plurality N, whereby in predetermined time steps a comparison with the predetermined residual charge R totIf the current residual charge reaches the specified residual charge value R tot For example, information can be issued to a user or a station that some of the discharged battery units 11-1, ..., 11-n need to be replaced. If the replacement is carried out automatically, the mobile system 1 can also travel to a corresponding station.

[0049] The described method enables a simultaneous and defined uneven (in the sense 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 until the battery units are changed and on the other hand also sufficient energy reserve during the battery unit change is ensured.

[0050] Please note that in this description, the term "charge" is used as a measure of the "fill level" of the battery units. Alternatively, the method can of course also be implemented using the energy contained as a "fill level measure."

[0051] Gentle discharging and high energy yield are achieved by ensuring that none of the N battery units 11-1, ..., 11-n remains unused in the battery system, but rather that all battery units 11-1, ..., 11-n from both the first and second groups Grp_I, Grp_II are always discharged with a different load share for each of the two groups. The first and second groups Grp_I, Grp_II are discharged simultaneously, with the battery units belonging to the second group Grp_II being discharged faster than the battery units belonging to the first group Grp_I, in order to ensure the supply of the general load 50 by the battery units of the first group Grp_I while the battery units of the faster-discharging group (second group Grp_II) are swapped.After replacing the initially faster-discharged battery units of the second group Grp_II, their fully charged battery units ensure the supply of the general load 50, so that the battery units of the first group Grp_I can be replaced. This process is then repeated cyclically.

[0052] For this purpose, as described in Fig. 2 is shown schematically, two sectionally defined discharge curves are generated from straight lines which have the following properties. Fig. Figure 2 shows a diagram illustrating a first and a second discharge curve y1, y2 for the first and second groups Grp_I, Grp_II of battery units, respectively. The sectionally defined discharge curves y1 for the battery units of the first group Grp_I and y2 for the battery units of the second group Grp_II are plotted against the typical standardized total capacity Q tot / C tot plotted. y1 and y2 represent the residual charge in percent (%).

[0053] The discharge curve y1 for the O battery units of the first group Grp_I is defined by two straight lines. The first straight line is 1 (100%) at Q tot / C tot = 1 (100 %) and decreases linearly to R tot / C tot / P · N at Q tot / C tot = R tot / C tot away.

[0054] For values ​​of Q tot / C tot > R tot / C tot the second straight section drops more steeply, so that at Q tot / C tot = 0 (0 %) to 0 (0 %). This results in the following definition for the O battery units of the first group Grp_I: y1(Qtot)={Qtot−RtotCtot−Rtot⋅(1−Rtot⋅NCtot⋅P)+Rtot⋅NCtot⋅Pfu¨rQtot≥RtotQtotCtot⋅NPfu¨rQtot <Rtot

[0055] The discharge curve y2 for the P battery units of the second group Grp_II is defined by 1 (100 %) at Q tot / C tot = 1 (100 %) and a linear decrease to 0 (0 %) at Qtot / C tot = R tot / C tot . For values ​​of Q tot / C tot > R tot / C tot it remains 0 (0%). For the P battery units of the second group Grp_II, the discharge curve y is determined as a function of the current total charge Q in the system. tot following definition: y2(Qtot)={Qtot−RtotCtot−RtotforQtot≥Rtot0forQtotCtot <RtotCtot

[0056] The Fig. The exemplary discharge curves y1, y2 shown in Figure 2 represent discharge specifications for the first and second groups Grp_I, Grp_II of battery units 11-1, ..., 11-n, where the specified residual charge R tot to 15%, the majority N = 6 and the numbers O = P = 3 were chosen.

[0057] The control algorithm described below ensures that the O battery units of the first group Grp_I, which initially have the highest current charge Q nthe plurality N of battery units 11-1, ..., 11-n, follow the discharge curve y1 when discharging and the units of the second group Grp_II of battery units follow the discharge curve y2.

[0058] For this purpose, the relative charge level of each battery unit Q n / C n compared with the discharge curve y1 or y2 responsible for them - depending on the state of charge - and a load share A n (n = 1 to N) via a proportional component k, as well as a manipulated variable limitation to a value range between A min and A max determined according to: An={min(max((QnCn−y1,2)⋅k;Amin);Amax)forQn>00forQn=0

[0059] The manipulated variable limitation to the value range between A min and A maxIt allows for limiting the oscillation around the specified discharge curve. The control variable limit also serves to prevent the battery units from being accidentally recharged due to the determined specifications. Furthermore, the control variable limit allows some charge to be drawn from almost empty battery units, resulting in better capacity utilization.

[0060] Completely empty battery units or battery units not plugged into the battery system 10 receive a load share A n = 0.

[0061] 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 experiments. The manipulated variable limitation A min is selected to be greater than 0. Values ​​less than 0 would result in the controller triggering a recharge between the battery units 11-1, ..., 11-n. Smaller values ​​for Amin in the range of [0, 1 ... 1] lead to a slight deviation from ideal behavior, ensure that even almost empty battery units are used and thus improve the overall running time of the battery system 10. A value in the range [1 ... 10] for A max gave good values ​​in experiments and is determined empirically.

[0062] With the load shares A n and the required total power L tot the current or power L to be drawn from each battery unit 11-1, ..., 11-n can be n (n = 1 to N) can be determined by determining the required total power L tot with the ratio of the respective load share A n to the sum of all load shares is multiplied according to: Ln=Ltot⋅An∑i=1…NAi

[0063] Fig. 3 shows the discharge curve of the exemplary N = 6 battery units (“Unit 1”, “Unit 2”, “Unit 3”, “Unit 4”, “Unit 5”, “Unit 6”) with a proportional component k = 10, A min = 0.1 and A max = 2, where again O = P = 3 and R tot= 15% are selected. It is clearly visible that three of the six battery units are assigned to 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 then approaches the assigned discharge specification y1 or y2 with its charge. In this exemplary embodiment, the curves labeled "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 curves labeled "Unit 4", "Unit 5", "Unit 6" belong to the P = 3 battery units of the second group Grp_II (with a lower current charge). The three battery units with the low charge ("Unit 4", "Unit 5", "Unit 6"), ieBattery units of the second group Grp_II become empty first and exactly when the three other 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.

[0064] 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.

[0065] Fig. Figure 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 Fig. 4, for the sake of clarity, has a different scaling of the discharge curve. Here, the horizontal axis does not indicate the total charge, but rather the qualitative temporal progression of the discharge at a constant discharge current. It is again clearly visible that the battery units of the second group Grp_II ("Unit 4", "Unit 5", "Unit 6") of the second group Grp_II are discharged faster than the battery units of the first group Grp_I ("Unit 1", "Unit 2", "Unit 3"), which represent the battery units of the first group Grp_I.

[0066] If the procedure is to ensure that after exchanging the empty battery units belonging to the second group Grp_II, the not yet completely empty battery units of the first group Grp_I are then discharged more quickly in order to be able to exchange them as soon as possible, the distance between A min and A maxreduced and, if necessary, the factor k increased.

[0067] Fig. 5 shows the rapid exchange of all six battery units (“Unit 1”, “Unit 2”, “Unit 3”, “Unit 4”, “Unit 5”, “Unit 6”) at a factor k = 100, A min = 1 and A max = 2, where the following also applies: The curves marked "Unit 1", "Unit 2", and "Unit 3" belong to the O = 3 battery units of the first group Grp_I (with higher current charge). The curves marked "Unit 4", "Unit 5", and "Unit 6" belong to the P = 3 battery units of the second group Grp_II (with lower current charge).

[0068] Assigning respective battery units to the first group Grp_I of battery units or the second group Grp_II of battery units after determining respective current charges Q noccurs initially, when the plurality N of battery units is fully charged and introduced into the battery system 10. Furthermore, the aforementioned steps are carried out after each replacement of the battery units belonging to the second group Grp_II by charged battery units or generally after each replacement of at least one battery unit.

[0069] The described method is also suitable, in a simpler embodiment, for discharging exclusively battery units of the second group Grp_II and protecting the battery units belonging to the first group Grp_I until the battery units from the second group Grp_II are completely discharged. Information is then generated that the battery units of the second group Grp_II can now be replaced, but do not have to be. 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 Rtot falls, a warning message is issued that the empty battery units must now be replaced if uninterrupted operation is to be ensured.

[0070] One advantage of the simpler design is that batteries are ready to be replaced as early as possible. Furthermore, this variant is particularly simple. A disadvantage is that the load is always unevenly distributed among the battery units, resulting in a lower energy yield due to the well-known Peukert effect and increased internal resistance. In addition, those battery units with a slightly above-average capacity are protected because fuller battery units are not discharged initially, and even after the emptier units are replaced with fuller units, charge is only drawn from the units in the other group with the lower capacity. This means that the battery units with the highest capacity remain unused in the system initially and possibly for a longer period of time. List of reference symbols 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 computing unit 50 load Grp_I first group of battery units Grp_II second group of battery units Q n current charge R tot Remaining charge

Claims

[1] Method for the uninterrupted operation of a network-independent mobile system (1), the mobile system (1) comprising: - an accumulator system (10) with a plurality N of removable battery units (11-1,..., 11-n) that can be recharged outside the mobile system; - a current control unit (20) with the plurality N of current regulators (21-1,..., 21-n), wherein each of the battery units (11-1,..., 11-n) is assigned a current regulator (21-1,..., 21-n) in order to adjust the current output of each of the battery units (11-1,..., 11-n) individually and independently of the other battery units (11-1,..., 11-n); - a charge determination unit (30) which is designed to determine a current charge (Q n ) and a current total charge (Q tot ) to determine; - a computing unit (40) which is designed to calculate, 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 ) to control the plurality N of current controllers (21-1,..., 21-n) of the current control unit (20); and - a general load (50); the method comprising the following steps: a) Determine the current charge (Q n ) each of the 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, wherein in the first group (Grp_I) the battery units with the highest current charge (Q n ) of the plurality N of battery units (11-1,..., 11-n) are included; 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, wherein in the second group (Grp_II) those battery units with the least current charge (Q n ) of the plurality N of battery units (11-1,..., 11-n) and where: P = N - O; d) Discharging the battery units (11-1,..., 11-n) until a specified residual charge (R tot ), where the residual charge (R tot ) is the charge required during a replacement of the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) of discharged battery units by charged battery units in order to supply the general load (50) without interruption during the replacement; 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 (11-1,..., 11-n) belonging to the second group (Grp_II) of discharged battery units by charged battery units is completed. [2] Method according to claim 1, characterized by that to supply the general load (50) until a predetermined residual charge (R tot ) the battery units of the battery units (11-1,..., 11-n) belonging to the first group (Grp_I) and the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) are discharged. [3] Method according to claim 1 or 2, characterized by that the battery units of the battery units (11-1,..., 11-n) belonging to the first group (Grp_I) and the battery units of the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) are provided with a different load share (A n ) can be discharged. [4] Method according to one of the preceding claims, characterized bythat the battery units of the battery units (11-1,..., 11-n) belonging to the first group (Grp_I) are discharged with a load share that is smaller than the load share of the battery units belonging to the second group (Grp_II) [5] Method according to one of the preceding claims, characterized by that the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) of battery units are completely discharged. [6] Method according to one of the preceding claims, characterized by that the battery units (11-1,..., 11-n) belonging to the first group (Grp_I) of battery units are completely discharged after the change. [7] Method according to one of the preceding claims, characterized bythat the discharge of the battery units (11-1,..., 11-n) belonging to the first group (Grp_I) by the respective current regulators (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 segments, and the discharge of the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) by the respective current regulators (21-1,..., 21-n) takes place in such a way that the respective current draw follows a predetermined second discharge curve (K_II) for the second group (Grp_II) of battery units, in particular with one straight line segment. [8] Method according to one of the preceding claims, characterized by that steps a) to c) are initially carried out when the plurality N of battery units (11-1,..., 11-n) are each fully charged. [9] Method according to one of the preceding claims, characterized bythat steps a) to c) are carried out dynamically, in particular after the replacement of the battery units (11-1,..., 11-n) belonging to one of the first or second groups (Grp_I, Grp_II) by charged battery units. [10] A computer program product which can be loaded directly into the internal memory of a digital computer and which comprises software code sections which carry out the steps according to any one of the preceding claims when the product is run on a computer. [11] Mobile system (1), comprising: - an accumulator system (10) with a plurality N of removable battery units (11-1,..., 11-n) that can be recharged outside the mobile system; - a current control unit (20) with the plurality N of current regulators (21-1,..., 21-n), wherein each of the battery units (11-1,..., 11-n) is assigned a current regulator (21-1,..., 21-n) in order to adjust the current output of each of the battery units (11-1,..., 11-n) individually and independently of the other battery units (11-1,..., 11-n); - a charge determination unit (30) which is designed to determine a current charge (Q n ) and a current total charge (Q tot ) to determine; - a computing unit (40) which is designed to calculate, 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 ) to control the plurality N of 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 perform the following steps: a) Determine the current charge (Q n ) each of the 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, wherein in the first group (Grp_I) the battery units with the highest current charge (Q n ) of the plurality N of battery units (11-1,..., 11-n) are included; 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, wherein in the second group (Grp_II) those battery units with the least current charge (Q n ) of the plurality N of battery units (11-1,..., 11-n) and where: P = N - O; d) Discharging the battery units (11-1,..., 11-n) until a specified residual charge (Rtot ), where the residual charge (R tot ) is the charge required during a replacement of the battery units (11-1,..., 11-n) belonging to the second group (Grp_II) of discharged battery units by charged battery units in order to supply the general load (50) without interruption during the replacement; 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 (11-1,..., 11-n) belonging to the second group (Grp_II) of discharged battery units by charged battery units is completed. [12] Device according to claim 11, characterized by that the computing unit (40) is designed to carry out the steps contained in one of claims 2 to 9.

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