Energy storage system

Abstract

To provide an energy storage system and a method for operating such an energy storage system for minimizing the internal energy consumption of the energy storage system.SOLUTION: The energy storage system includes multiple energy storage modules and a control device. The control device is configured to specify operating conditions of the energy storage system for a predetermined time period and to select one of the modules depending on the specified operating conditions of the energy storage system and at least one internal parameter of each of the multiple energy storage modules. Furthermore, the control device is configured to determine whether the selected storage module is to absorb energy, release energy, or halt operation on the basis of the specified operating conditions of the energy storage system and at least one internal parameter of the selected energy storage module.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an energy storage system including a plurality of power storage modules and a method for operating such an energy storage system.

Background Art

[0002] In an energy storage system, basically, only a part of the energy supplied to the system for storage can be taken out again and then, for example, supplied to another device or another system. For example, self-discharge of power storage modules that usually occurs in a flywheel generator or a battery is an example of inevitable energy loss that can be regarded as internal energy consumption of the energy storage system. Further, in order to maintain the function of the energy storage system, a certain amount of energy is required, and electronic devices for controlling and monitoring each energy storage system also require a certain amount of energy. When the required amount of energy is taken out from the energy storage system itself instead of being supplied from the outside, the maintenance of the function of the energy storage system and the electronic devices are also related to internal energy consumption.

[0003] When the energy storage system includes, for example, batteries, a certain amount of energy may be required to heat or cool those batteries. On the other hand, when the energy storage system includes one or more flywheel generators, inevitable energy losses occur due to mechanical friction and friction with gas, but they can be reduced by the operation of the flywheel in a vacuum and magnetic axial support of the flywheel. However, the generation of a vacuum and magnetic axial support also requires a certain amount of energy consumption, which is taken out from, for example, the flywheel generator itself, and in that case, it contributes to the internal energy consumption of the energy storage system.

[0004] The energy storage system can further include a plurality of energy storage modules, in which case different module types can be distinguished by certain characteristics. For example, batteries and flywheel energy storage devices differ with respect to self-discharge, temperature sensitivity, and charge cycles. The charging performance, i.e., the amount of energy that can be supplied to each energy storage module within a given time period, varies significantly between batteries and flywheel energy storage devices. This also applies to the maximum amount of energy that can be extracted from a battery or flywheel energy storage device within a given time period. Furthermore, flywheel energy storage devices are suitable without problems for full discharge, i.e., the extraction of energy until the energy holding amount is almost zero, while for batteries, such full discharge should be avoided in order to extend their lifespan.

[0005] The energy storage system can further include a plurality of modules of the same type, for example, a plurality of flywheel energy storage devices or a plurality of batteries, or a combination of modules of different types, for example, one or more batteries and one or more flywheel energy storage devices simultaneously. In such an energy storage system, the above-mentioned energy losses and the amount of energy for maintaining the functions occur for each module, and these modules are usually handled independently of each other or controlled with respect to the normal energy balance.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] The problem of the present invention is to realize an energy storage system and an operating method of such an energy storage system that can minimize the internal energy consumption of the energy storage system.

MEANS FOR SOLVING THE PROBLEM

[0007] This problem is solved by an energy storage system and method having the features of the independent claims. Advantageous improvements of the present invention are presented in the dependent claims, the specification, and the drawings.

[0008] This energy storage system includes a plurality of power storage modules and one control device. This control device is configured to identify the operating conditions of the energy storage system for a predetermined time period, and to select one of these power storage modules depending on the identified operating conditions of this energy storage system and on at least one internal parameter of each of the plurality of power storage modules. Further, this control device is configured to determine whether the selected power storage module is to take in energy, release energy, or stop operating, based on the identified operating conditions of the energy storage system and on at least one internal parameter of the selected power storage module.

[0009] The operating conditions of the energy storage system can include, for example, the respective states in which energy is supplied to the energy storage system or energy is taken out from the energy storage system, and an operation stop state in which energy is neither supplied to the energy storage system nor taken out from the energy storage system. Further, these operating conditions can include, for example, special states such as maintenance time. These operating conditions are further specified for future points in time within a predetermined time period, and can include whether energy should be supplied to the energy storage system at one or more of these future points in time, or energy should be taken out from the energy storage system, or the energy storage system should be stopped from operating during the time period between two future points in time, that is, should neither take in nor release energy.

[0010] This predetermined time period can include the current time and can extend to past times, for example, from the distant past, and future times, for example, in the near future. However, alternatively, this predetermined time period can include only future time periods. Therefore, when this control device defines the operating conditions of the energy storage system for a predetermined time period, this control device can, on the one hand, determine the current operating conditions and, on the other hand, predict the future operating conditions, or one or more of them. Such prediction of future operating conditions can include, for example, that energy should be supplied from the energy storage system to a predetermined device at a predetermined future time period, or that another device already knows at the current time that it can supply energy that can be captured by the energy storage system after a future time point.

[0011] In addition to, or alternatively to, specifying the current or future operating conditions of the energy storage system, that is, in addition to external conditions, this control device selects one of these power storage modules taking into account at least one internal parameter of each of the plurality of power storage modules. This internal parameter can include, for example, the energy holding amount, and in the case of a power storage module, this amount can be the state of charge of each power storage module. Furthermore, a plurality of other internal parameters, for example, the temperature of each power storage module, or the self-discharge or achievable charging capacity of a predetermined module type can also be considered.

[0012] The advantages of this energy storage system are, first, to select one of the power storage modules using a control device, depending on external conditions and on the current internal situation of a plurality of power storage modules, and then to adapt the selected power storage module to specified operating conditions and optimize it with respect to its energy balance, taking into account the internal state of the selected power storage module. The decision as to whether the selected power storage module should take in energy, release energy, or stop operating can be made so as to conform to the operating conditions, for example, so as to minimize the amount of energy necessary to maintain the function of the selected power storage module. Therefore, this control device can select and control one of the power storage modules and minimize its internal energy consumption.

[0013] However, such optimization of internal energy consumption can be carried out in a manner related to another power storage module of the energy storage system. For example, with respect to the energy holding amount of the selected power storage module, if it is specified as its internal parameter that the amount falls below a predetermined threshold value, this control device can, for example, realize that the selected power storage module stops operating after releasing its remaining energy holding amount to one or more other power storage modules. Conversely, if the specified operating conditions include that a predetermined amount of energy can be provided from another device to supply energy to the energy storage system, for example, one of the power storage modules can be selected based on its current energy holding amount and its current or future energy intake capacity. Next, since this power storage module is most suitable for taking in this amount of energy currently or in the near future, it can take in the provided amount of energy.

[0014] Furthermore, the selection of one of the plurality of power storage modules for optimizing the energy balance can be repeatedly performed using a control device. For example, first, select a power storage module and discharge the required amount of energy until the energy storage of that power storage module is exhausted, then select the next power storage module and discharge the required energy until the energy storage of that power storage module is also exhausted, and so on. In this way, after sequentially extracting energy, it is possible to realize that the operation of each power storage module of the energy storage system can be stopped. As a result, the number of currently or future-operating power storage modules of the energy storage system can be minimized, and thus the total amount of energy required to maintain the function of the energy storage system can be minimized.

[0015] Overall, with regard to the intake and discharge of energy and the stoppage of operation, selecting one of the plurality of power storage modules and treating that power storage module specially realizes minimizing the internal energy consumption of the energy storage system. This further causes the extension of the lifespan and the improvement of the operation rate of the energy storage system. Furthermore, particularly when the operation of selecting and treating one of the plurality of power storage modules specially is repeatedly performed, the efficiency of the intake and discharge of energy of the entire energy storage system can be optimized.

[0016] In one implementation, this control device can further be configured to determine whether another energy storage module of the energy storage system takes in the energy released from the selected energy storage module or whether the energy storage system releases the energy released from the selected module to an external device based on the specified operating conditions of the energy storage system and based on at least one internal parameter of the selected energy storage module. Therefore, if it is predetermined that the selected energy storage module releases energy based on an external criterion for determining the operating conditions of the energy storage system and based on the internal criterion or characteristics of the selected energy storage module, it is possible to determine where to direct the energy flow from the selected energy storage module. This can optimize the efficiency of the energy flow when releasing energy to devices inside and outside the energy storage system.

[0017] If the selected energy storage module is configured as, for example, a flywheel energy storage machine and an external device requests the release of a large amount of energy from the energy storage system, such a flywheel energy storage machine can release at least a portion of the requested amount of energy to the external device within a relatively short time period as long as the energy holding amount of the flywheel energy storage machine exceeds a predetermined threshold. However, if such a flywheel energy storage machine has a relatively small energy holding amount, for example, below a predetermined threshold, this control device can instead determine to transmit the remaining energy holding amount of the flywheel energy storage machine to another energy storage module of the energy storage system, such as another flywheel energy storage machine or a battery.

[0018] At least one internal parameter of this energy storage module can include the energy holding amount of each energy storage module. When the energy storage modules of the energy storage system are configured to take in and discharge electrical energy, this internal parameter can specifically include the state of charge of each energy storage module. Further, in order to identify the selected energy storage module, a plurality of internal parameters of each energy storage module can be considered. When the energy storage module is configured to take in and discharge electrical energy, these plurality of internal parameters can include, for example, the state of charge, self-discharge, and / or the amount of energy that can be taken in per unit time, i.e., characteristics related to the charging performance of each energy storage module.

[0019] Furthermore, the amount of energy to be supplied to or taken out from the energy storage system within a predetermined time period can be allocated to the specified operating conditions. Therefore, by treating the selected energy storage module specially, the operating conditions of the energy storage system can be specified so that the energy storage system can be adapted to the supply and demand of the amount of energy to be taken in or taken out. As a result, overall, the energy balance of the energy storage system can be further optimized.

[0020] Furthermore, the amount of energy allocated to the specified operating conditions can be associated with, for example, the amount of energy expected to be taken out by a consumer, such as an electric vehicle to be charged using the energy storage system. Further, the amount of energy related to the operating conditions of the energy storage system can include, for example, the expected energy supply to the energy storage system by the night-time power from the power grid to which the energy storage system can be connected. In this case, the control device of the energy storage system can identify or determine the future operating conditions of the energy storage system and select the energy storage modules of the energy storage system that are likely to be able to take in the energy supply, specifically, the night-time power.

[0021] In another implementation configuration, this control device can further be configured to define the operating conditions of the energy storage system based on the state of an external device that is connected to the energy storage system and configured to transmit energy to the external device. In this implementation configuration, the determination of the selected power storage module and its special handling or special control can be adapted to the requirements of the external device for determining the operating conditions of the energy storage system. Thereby, the energy flow from the energy storage system or from the selected power storage module to the external device can be optimized, for example, with respect to the amount of energy transmitted to the external device within a predetermined time period. This external device can be any consumer or, for example, the battery of an electric vehicle to be charged within a predetermined time period.

[0022] In another implementation configuration, this control device can further be configured to identify the operating conditions of the energy storage system based on the parameters of an external device that can be connected to the energy storage system to transmit energy to the energy storage system. In this implementation configuration, the external device can be composed of any energy source, for example, a device that generates energy such as a power grid, a solar power generation facility, or another energy storage system. The parameters of this external device can include, for example, the amount of energy that can be provided during a predetermined time period or the power during energy transmission, that is, the maximum amount of energy that can be transmitted per unit time. Therefore, in this implementation configuration, the selection and control of one of the power storage modules when taking in the amount of energy from the external device can be adapted to the characteristics of this external device.

[0023] In another implementation configuration, this control device can further control a plurality of power storage modules such that only the selected power storage module releases energy until the energy holding amount of the selected power storage module falls below a predetermined threshold value, while another power storage module does not release energy, and when the energy holding amount falls below the predetermined threshold value, the operation of the selected module is configured to be stopped.

[0024] When these power storage modules are configured to take in and discharge electrical energy, the energy holding amount can include the state of charge of each power storage module. In this implementation configuration, the selected power storage module is, so to speak, for example, after another power storage module has been selected as described above and then emptied for the first time as a single module and before its operation is stopped, emptied for the first time with respect to the energy holding amount and then its operation is stopped. Therefore, the control according to this implementation configuration can be executed repeatedly, and as a result, one power storage module is sequentially stopped after another power storage module.

[0025] By emptying each single module and then stopping the operation, the number of power storage modules operating at a given time can be minimized, and as a result, the internal energy consumption or self-consumption of the power storage modules is minimized as a whole. This is particularly applicable when emptying and stopping the operation of a plurality of power storage modules sequentially.

[0026] In another implementation configuration, these power storage modules are composed of at least two different module types. The power storage module of the first module type is configured to have its energy extracted until it reaches a first remaining energy holding amount, while the power storage module of the second module type can be configured to have its energy extracted until it reaches a second remaining energy holding amount. The first remaining energy amount can be made smaller than the second remaining energy amount.

[0027] The power storage module of the first module type can be considered, for example, to be suitable for so-called full discharge where the first remaining energy holding amount becomes very small, especially zero. In other words, the power storage module of the first module type can advantageously be fully discharged. An example of such a power storage module is a flywheel energy storage machine.

[0028] In contrast, the energy storage module of the second module type can be considered an energy storage device that should avoid full discharge or complete discharge during the operation of the energy storage module. In one example, the second module type is composed of a battery where a complete discharge may have an adverse effect on its lifespan.

[0029] Furthermore, the energy storage module of the first module type can have a first internal energy consumption, while the energy storage module of the second module type can have a second internal energy consumption. The first internal energy consumption can be greater than the second internal energy consumption.

[0030] Each energy consumption of the energy storage module of the first or second module type can be caused, in particular, by the self-discharge of the energy storage module. Therefore, this self-discharge can be greater in the first module type than in the second module type. For example, the self-discharge of a flywheel energy storage is considerably greater than that of a battery. Furthermore, the operation of a flywheel energy storage may require additional energy consumption, for example, for the generation of a vacuum to reduce friction with gas and for magnetic bearings to reduce mechanical friction. The additional energy consumption for magnetic bearings and the generation of a vacuum does not occur in a battery.

[0031] Furthermore, the first module type and the second module type can be distinguished by different charging / discharging characteristics. For example, it can be assumed that the energy storage module of the first module type is suitable for discharging a larger amount of energy than the energy storage module of the second module type within a predetermined time, that is, it is suitable for a larger discharge capacity. Similarly, conversely, it can be assumed that the energy storage module of the first module type is suitable for taking in a larger amount of energy per unit time than the energy storage module of the second module type, that is, it is suitable for a larger charging performance. Furthermore, it can be assumed that the energy storage module of the second module type has less energy loss due to self-discharge during storage than the energy storage module of the first module type.

[0032] As already mentioned previously, the energy storage module of the first module type can be configured as a flywheel energy storage device, while the energy storage module of the second module type can be configured as a battery. Combinations of different module types in such a plurality of energy storage modules can have the advantage that the energy storage system can be optimally adapted to the respective current or future operating conditions of the energy system during operation. Furthermore, when there are two different module types of energy storage modules, the internal energy consumption of the energy storage system can be reduced.

[0033] If the future operating conditions of the energy storage system are configured such that, for example, they can take in a large amount of energy provided by an energy generation device or the power grid, the control device of the energy storage system can select one or more power storage modules of the first module type, for example, one or more flywheel energy storage devices, in order to take in the provided amount of energy. This also applies to the operating conditions of the energy storage system that it should also be able to extract a large amount of energy in a short time. Regarding such operating conditions, a power storage module of the first module type can be selected, because it can be assumed that the power storage module is more suitable for full discharge than, for example, a power storage module of the second module type. Specifically, in order to extract a large amount of energy, one or more flywheel energy storage devices suitable for full discharge until the energy holding amount becomes zero can be selected, and this does not have an adverse effect on the life of each flywheel energy storage device.

[0034] During the operation of the energy storage system, this control device can transmit the energy holding amounts of one or more power storage modules of the first module type or the second module type to one or more power storage modules of a different module type respectively depending on the operating conditions of the energy storage system and each internal parameter of the power storage module, thereby controlling the power storage modules of the first module type and the second module type so as to minimize the number of operating power storage modules. For example, when the flywheel energy storage device operates at a low rotational speed and thereby has a small amount of energy, the energy holding amount or charge amount of the flywheel energy storage device representing the first module type can be transmitted to the battery belonging to the second module type. In this case, further, based on the specified operating conditions of the energy storage system, if it can be detected that a large amount of energy should not be supplied to or extracted from the energy storage system for a predetermined future time period, the flywheel energy storage device can stop operating after transmitting its remaining energy to the battery.

[0035] Therefore, the use of two different types of energy storage modules can be pre - adapted to the current and future operating conditions of the energy storage system, i.e., with respect to a predetermined time period, using a control device. Thereby, the internal energy consumption of the energy storage system can be further reduced.

[0036] In another implementation configuration, at least one energy storage module is configured as a flywheel energy storage machine. Therefore, in this implementation configuration, the energy storage system includes at least one energy storage module suitable for full discharge until the state of charge or the energy holding amount becomes zero. Thereby, it can be assumed that the energy storage system can take in a large amount of energy within a short time period and release it again. In this implementation configuration, another energy storage module of the energy storage system can also be a flywheel energy storage machine, and as a result, all the energy storage modules of the energy storage system are configured as flywheel energy storage machines. Instead, these energy storage modules can be composed of one or more flywheel energy storage machines and one or more batteries, which are not suitable for full discharge, but have the advantages of low self - discharge and thus low internal energy consumption.

[0037] The flywheel energy storage machine can be equipped with magnetic bearings and vacuum equipment. This control device can further be configured to stop the operation of the magnetic bearings and at least partially stop the vacuum equipment during the stop of the operation of the flywheel energy storage machine. Therefore, when the flywheel energy storage machine is selected as an energy storage module that stops operating after completely discharging its energy holding amount based on the current or future operating conditions of the energy storage system, the internal energy consumption of the energy storage system can be reduced by also stopping or at least partially stopping the operation of the magnetic bearings and vacuum equipment of the flywheel energy storage machine.

[0038] When stopping the vacuum machine, in order to reduce the friction with the gas, one or more vacuum pumps equipped to evacuate one or more flywheel generators can be stopped sequentially. This can depend on the number of vacuum pumps assigned to the one or more flywheel generators. For example, when one vacuum pump evacuates multiple flywheel generators, each time the operation of a flywheel generator is stopped, the rotational speed of the vacuum pump can be decreased by a predetermined amount respectively.

[0039] At least one other energy storage module, i.e., in addition to at least one flywheel generator, can be configured as a battery, and this control device can further be configured to control the energy storage module to transmit the energy holding amount of the flywheel generator to the battery when the energy holding amount of the flywheel generator falls below a predetermined threshold. This control device can then stop the operation of the flywheel generator.

[0040] For example, when the rotational speed of the flywheel generator is low with respect to the overall internal energy consumption of the energy storage system, it can be considered advantageous to completely empty or discharge the flywheel generator by transmitting its energy holding amount to the battery. This control device can, for example, detect that a large amount of energy should not be taken out of the energy storage system within a predictable time and identify the operating conditions accordingly. In this case, in order to minimize the overall internal energy consumption of the energy storage system, the operation of the flywheel generator can be stopped after its discharge.

[0041] In another implementation, this control device is further configured to identify a first time point after which the energy storage system should capture a first amount of energy, and to identify a second time point after which the energy storage system should release a second amount of energy. Further, based on the time difference between the first time point and the second time point, based on the first amount of energy, and based on the second amount of energy, this control device can determine whether the flywheel generator or the battery can release the second amount of energy after capturing the first amount of energy. Therefore, in this implementation, the operating conditions of the energy storage system specified or defined by the control device not only depend on whether the energy should be taken out or released after the first time point or the second time point, but also depend on the time period or time difference between these two time points. Therefore, in this implementation, the operating conditions of the energy storage system can include the current operating conditions at the first time point, the future operating conditions at the second time point, and optionally, the future operating conditions at another future time point.

[0042] For example, if the first amount of energy is relatively large and exceeds a predetermined threshold, and further, the second amount of energy is within a similar range, and further, the time difference between the first time point and the second time point is relatively short, i.e., for example, shorter than a predetermined time interval, the flywheel generator can capture the first amount of energy so that the second amount of energy can be released again within a relatively short time period. The prerequisite for this is, of course, that the overall energy holding of the flywheel generator including the first amount of energy is larger than the second amount of energy. In this scenario, it can be considered that the fact that the flywheel generator has a larger internal energy consumption than the battery is not very relevant. Instead, based on the specified operating conditions of the energy storage system, i.e., based on the relatively large second amount of energy to be released in the near future, it can be considered that it is more relevant that the flywheel generator can provide the second amount of energy within a relatively short time period.

[0043] Conversely, within a relatively long future time period, for example, overnight, it is expected that the required energy amount to be taken out from the energy storage system as the second energy amount is not large or not present at all. At the same time, if a predetermined first energy amount is required for storage in the energy storage system, based on such operating conditions, this control device can select a battery as the power storage module that supplies the first energy amount. In this scenario, since the first energy amount has to be held for a longer time after its storage, the internal energy consumption of the power storage module of the energy storage system plays a more significant role.

[0044] Therefore, in the two scenarios described above, by selecting the optimal power storage module, the energy balance of the energy storage system can be optimized to conform to the specified operating conditions.

[0045] Another object of the present invention is a method for operating an energy storage system provided with a plurality of power storage modules and one control device. In this method, first, the operating conditions of the energy storage system assigned to a predetermined time period are specified. Next, depending on the specified operating conditions of this energy storage system and on at least one internal parameter of each of the plurality of power storage modules, one of the plurality of power storage modules is selected, and based on the specified operating conditions of this energy storage system and on at least one internal parameter of the selected power storage module, it is determined using this control device whether the selected module takes in energy, discharges energy, or stops operating.

[0046] Regarding this method, the above detailed description regarding the energy storage system applies accordingly, which is particularly applicable regarding advantages and advantageous implementation configurations. Furthermore, it is self-evident that all the features mentioned here can be combined with each other as long as no contrary description is explicitly presented.

[0047] Hereinafter, with reference to the accompanying drawings, examples of the present invention will be described based on advantageous embodiments.

Brief Description of the Drawings

[0048]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0049] FIG. 1 schematically illustrates an energy storage system 100 according to the prior art and its operation method, that is, a method of operating the energy storage system 100. In this embodiment, this energy storage system 100 includes a plurality of power storage modules 110 each configured as a flywheel generator 115, and a control device 120 connected to the power storage modules 110 of the energy storage system 100 by signal technology and communication. These power storage modules 110 are further arranged to take in, store, and extract electrical energy.

[0050] This control device 120 controls the supply of energy to the power storage module 110 and the extraction of energy from the power storage module 110, and also controls internal parameters of the power storage module 110, for example, parameters of the magnetic bearing and the vacuum system of the flywheel electric generator 115 (see FIGS. 3 and 4), and when at least a part of the power storage module 110 is configured as a battery, parameters related to heating or cooling of the battery 515 (see FIG. 5). The energy holding amount 130 of each power storage module 110, that is, the flywheel electric generator 115 (see FIG. 1) and / or the battery 515 (see further FIG. 5) is indicated by a crossbar in each module 110.

[0051] FIG. 1 further illustrates the time sequence during the operation of the energy storage system 100 regarding the phase of extracting energy from the energy storage system 100 and releasing it to an external device (not shown). Specifically, the energy holding amount 130 of each power storage module 110 of the energy storage system 100 at four different time points t1, t2, t3, and t4 is illustrated. For ease of viewing, this control device 120 is illustrated only at the first time point t1. However, the power storage module 110 is always, that is, also connected to the control device 120 at the subsequent time points t2, t3, t4.

[0052] At time t1, all the power storage modules 110 or the flywheel generator 115 of the energy storage system 100 are fully charged, which is illustrated by three horizontal bars respectively regarding the energy holdings 130 of each power storage module 110. When extracting energy from the energy storage system 100 for external devices, this control device 120 controls a plurality of power storage modules 110 based on the prior art to simultaneously extract energy from each of the power storage modules 110. Extracting energy equally from all the power storage modules 110 or the flywheel generator 115 in this way is illustrated by the energy holdings 130 of two horizontal bars at time t2 respectively, and by the energy holdings 130 of one horizontal bar at time t3. Further, the block arrows 140 indicate the transitions from one of the times t1, t2, and t3 to the next times t2, t3, and t4 respectively. As can be recognized based on the time sequence of the energy holdings 130 of each power storage module 110, energy is extracted equally in parallel from these power storage modules 110 until the energy holdings 130 of the power storage modules 110 become almost zero at time t4.

[0053] The drawback of the operation method of the energy storage system 100 according to the prior art is that while extracting energy from the energy storage system 100, all the power storage modules 110 are operating, and thus each has internal energy consumption. The internal energy consumption of the power storage module 110 configured as a flywheel generator 115 is caused, on the one hand, by the magnetic bearings and the generation of vacuum (see also FIG. 3) of each flywheel generator 115 that reduce the mechanical friction and gas friction between the components of each flywheel generator 115, and on the other hand, by the operation of the electronic devices that control and monitor the power storage modules 110 held by the control device 120.

[0054] FIG. 2 schematically illustrates an energy storage system 101 according to the present invention and a method of operating the corresponding system thereof. This energy storage system 101 includes a plurality of power storage modules 110 each configured as a flywheel generator 115 and a control device 121. This control device controls the power storage modules 110 in a different manner from the control device 120 according to the prior art. For ease of viewing, this control device 121 is shown only at the first time point t1. However, the power storage modules 110 are always connected to the control device 121, that is, also at subsequent time points t2, t3, and t4.

[0055] In FIG. 2, the energy amount 130 of each power storage module 110 is displayed by a horizontal bar in the same manner as in FIG. 1 at four different time points t1, t2, t3, and t4. During the phase between time points t1 and t4, energy for an external device (not shown) is also taken out from the energy storage system 101 in the same manner as described above for the prior art energy storage system 100. However, this control device 121 specifies the operating conditions of the energy storage system 101 at time point t1, which in this case includes that energy for the external device should be taken out from the energy storage system 101. Further, this control device 121 specifies the internal parameters of each power storage module 110, for example, its energy holding amount or state of charge 130.

[0056] At time point t1, this control device 121 selects one of the energy storage modules 110 or one of the flywheel energy storage machines 115, for example, the first energy storage module 111, and first extracts energy only from the selected energy storage module 111. At time point t2, the first energy storage module 111 is almost completely discharged or emptied, and as a result, its energy holding amount 130 becomes almost zero. Therefore, at time point t2, this control device 121 selects the second energy storage module 112 to extract energy for the external device. At the same time, the operation of the first energy storage module 111 is stopped, and as a result, the generation of its vacuum and the internal energy consumption for the magnetic bearing are eliminated. The operation stop of the first energy storage module 111 and the subsequent second energy storage module 112 is indicated by showing the outer contour of this energy storage module with a dotted line.

[0057] At time point t3, the second energy storage module 112 is also completely discharged or emptied, and as a result, the second energy storage module 112 is also stopped from operating at time point t3. At the same time, the third energy storage module 113 is activated at time point t3, and as a result, after time point t3, energy is extracted only from the third energy storage module 113.

[0058] At time point t4, the third energy storage module 113 certainly has a smaller energy holding amount than at time point t3. However, since the first and second energy storage modules 111, 112 were previously stopped from operating and their internal energy consumption for the magnetic bearing and the generation of the vacuum has already disappeared for a certain time period, at time point t4, the third energy storage module 113 still has, that is, different from the energy storage module 110 of the prior art energy storage system 100, a certain amount of residual energy holding amount 135.

[0059] Therefore, the energy storage system 101 according to the present invention is different from the prior art energy storage system 100 in that during the phases between time points t1 to t4 when energy is extracted from the energy storage systems 100 and 101, the operations of the power storage modules 110 are sequentially stopped. Sequentially stopping the operations of the power storage modules 110 is achieved by sequentially selecting one of the power storage modules 110, first extracting energy only from the selected power storage modules 111, 112, 113, etc., completely discharging it, and then stopping the operation.

[0060] Therefore, by sequentially stopping the operations of the power storage modules 110 of the energy storage system 101, the internal energy consumption of the energy storage system 101 is reduced. Further, the power storage modules 110 of the energy storage system 101 according to the present invention are completely stopped more frequently during their operations than the prior art energy storage system 100, so that maintenance work for each power storage module 110 that requires complete stoppage of operation can be planned more easily. In other words, since the operations are sequentially stopped, opportunities to maintain each power storage module 110 of the energy storage system 101 are frequently obtained, while at the same time, the energy storage system 101 remains in an operable state.

[0061] Sequentially stopping the operations of the power storage modules 110 described above can also be applied to an energy storage system that uses a battery instead of the flywheel generator 115, for example, in the case of an energy storage system of a storage system 501 equipped with a battery 515 in addition to the flywheel generator 115 as shown in FIGS. 5 and 6. These batteries 515 can also be sequentially disconnected from the energy storage system 501 one after another, and at that time, they can be sequentially discharged to a certain state of charge in order to reduce or completely stop their heating or cooling. As a result, the internal energy consumption of each power storage module 110 and thus the entire energy storage system 501 is reduced.

[0062] Figures 3 and 4 illustrate an energy storage system 101 according to the present invention, each provided with a vacuum system 300 or 400 respectively arranged to generate a vacuum in the flywheel generator 115 of the energy storage system 101. The vacuum system 300 in FIG. 3 includes a plurality of vacuum pumps 310, one of which is assigned to each flywheel generator 115 respectively. These vacuum pumps 310 are connected to the control device 121 by signal technology or communication for their control, similar to the power storage modules 110 or the flywheel generators 115. This applies to all time points t1, t2, and t3 illustrated in FIGS. 3 and 4, even though the control device 121 is explicitly illustrated only at the first time point t1.

[0063] At time point t1, first, all the power storage modules 110 or flywheel generators 115 of the energy storage system 101 are operating, and as a result, all the vacuum pumps 310 of the vacuum system 300 are operating. As previously explained, at time point t2, since the first power storage module 111 is completely discharged or emptied, the operation of the first power storage module 111 is stopped at that time. The stop of the operation of the first power storage module 111 also includes stopping the operation of the vacuum pump 311 assigned to the first power storage module 111.

[0064] At time point t3, since the operation of the second power storage module 112 is additionally stopped, at that time, the operation of the vacuum pump 312 assigned to the second power storage module 112 is also stopped. Therefore, each vacuum pump 310 assigned to one of the power storage modules 110 is stopped and operated again as needed together with each power storage module 110. As a whole, the vacuum system 300 is adapted to each state of the power storage module 110 by the operation or stop of the vacuum pumps 311, 312.

[0065] The vacuum system 400 for the flywheel generator 115 of the energy storage system 101 according to the present invention, shown in FIG. 4, is different from the vacuum system 300 of FIG. 3 in that only one vacuum pump 410 is allocated to all the power storage modules 110 of the energy storage system 101. At time t1, since all the power storage modules 310 of the energy storage system 101 are operating, the vacuum pump 410 is operating at full power or at a high rotational speed. The high rotational speed of the vacuum pump 410 is indicated by the display of the corresponding rotational speed measuring device 415.

[0066] However, when the first power storage module 111 stops operating at time t2, it is still necessary to generate a vacuum only in the remaining power storage modules 110, but since there is no longer a need to generate a vacuum in the first power storage module 111 that has stopped operating, the rotational speed of the vacuum pump 410 is correspondingly reduced. When the second power storage module 112 also stops operating at time t3, again, as indicated by the display of the rotational speed measuring device 415, the rotational speed of the vacuum pump 410 is further reduced accordingly. That is, at time t3, there is no longer a need to generate a vacuum in the first and second power storage modules 111, 112.

[0067] By adapting the vacuum systems 300, 400 according to the number of operating power storage modules 110 of the energy storage system 101, the number of operating vacuum pumps 310 matches the number of operating power storage modules 110 (see FIG. 3), or the rotational speed of the vacuum pump 410 is adapted to the number of operating power storage modules 110. Thus, overall, the internal energy consumption of the energy storage system 101 is reduced.

[0068] Figures 5 and 6 schematically illustrate an energy storage system 501 with a plurality of power storage modules 110 as an alternative implementation configuration. These power storage modules 110 are each configured as a flywheel energy storage machine 115 or as a battery 515. Therefore, in this implementation configuration, the power storage modules 110 are composed of at least two module types. These power storage modules 110 are also each connected to the control device 121 of the energy storage system 501.

[0069] Figure 5 illustrates a scenario or operating condition of the energy storage system 501 in which one of the flywheel energy storage machines 115 has a relatively small energy holding 130. When the energy holding 130 of this flywheel energy storage machine 115 becomes smaller than a predetermined threshold value, the control device 121, as shown on the right side of Figure 5, realizes completely discharging or emptying this flywheel energy storage machine 115 and transmitting the remaining energy holding 130 to one of the two batteries 515. Therefore, the control device 121 observes or measures the energy holding 130 of each power storage module 110 as one of the internal parameters of the power storage module 110, and controls and optimizes the energy balance of the energy storage system 501 depending on such internal parameters. Furthermore, the control device 121 is also connected to the power storage module 110, although not explicitly shown with respect to the scenario illustrated on the right side of Figure 5.

[0070] As can be recognized on the right side of FIG. 5, the energy storage module 110 equipped with the flywheel generator 115 is completely stopped when its energy holding amount becomes almost zero as shown by the dotted line. Compared with the state on the left side of FIG. 5, in the state on the right side, one of the batteries 515 has a larger energy holding amount 137. In the state on the right side of FIG. 5, since one of the flywheel generators 115 is stopped, its internal energy consumption is eliminated. Therefore, by transmitting the remaining energy holding amount 130 from one of the flywheel generators 115 to one of the batteries 515, the overall internal energy consumption of the energy storage system 501 is reduced.

[0071] In this scenario, the optimization or reduction of the internal energy consumption of such an energy storage system 501 can be achieved by the presence of two different module types of storage modules 110 in the energy storage system 501. The flywheel energy storage module 115 as the first module type is suitable for so-called full discharge without problems, that is, it can be completely discharged or emptied without adversely affecting the life of the flywheel energy storage module 115.

[0072] Therefore, since the flywheel generator 115 has a larger internal energy consumption compared to the battery 515, this control device 121 controls the energy storage module 110 of the energy storage system 501 so that the flywheel generator 115 is not operated in an adverse state where the energy holding amount 130 is small. Therefore, since full discharge may adversely affect the life of the battery 515, the small energy holding amount 130 of the flywheel generator 115 has as little internal energy consumption as possible, but is transmitted to one or more batteries 515 that are less suitable than the flywheel generator 115 for discharge or full discharge until the energy holding amount becomes almost zero.

[0073] FIG. 6 illustrates two different scenarios or operating conditions of an energy storage system 501 including a plurality of flywheel electrical storage machines 115 and a plurality of batteries 515. Although not explicitly shown, in the scenarios illustrated in FIG. 6, the control device 121 of the energy storage system 501 is also connected to the power storage modules 110, respectively.

[0074] In the scenario on the left side of FIG. 6, this control device 121 first identifies that after a predetermined first time point, the energy storage system 501 can take in a relatively large first amount of energy provided from an external device. In other words, at the current time, that is, after the first time point, there is a supply from which the energy storage system 501 can take in advantageous energy, and this first amount of energy or advantageous energy is provided, for example, by a solar power generation facility or by an appropriate supply in the power grid.

[0075] Furthermore, this control device 121 identifies that in the near future, that is, for example, after a second time point in the near future immediately after the first time point, there will be a high probability of a large demand occurring and a relatively large amount of energy will be taken out from the energy storage system 501. Such a near-future demand can be given, for example, as shown in FIG. 6, by the fact that the electric vehicle 610 should be charged after a known time point. Due to the relatively short time difference between the first time point when the energy supply is available and the second time point when a large demand for taking out energy from the energy storage system 501 is expected, this control device 121 decides to use the power storage module 110 including the flywheel electrical storage machine 115 to take out the amount of energy after taking it in.

[0076] The minimum time difference between the first point in time and the second point in time when the energy storage module 110 equipped with the flywheel generator 115 is used and the energy storage module 110 equipped with the battery 515 is no longer used can be determined in advance based on empirical values. Furthermore, the time difference as a limit value regarding the use of this flywheel generator 115 can be determined with respect to the internal parameters of the two module types of the energy storage system 501, for example, regarding the self-discharge and internal energy consumption of the individual energy storage modules 110 equipped with the flywheel generator 115 or the battery 515.

[0077] In the scenario illustrated on the left side of FIG. 6, where a large energy demand for charging the electric vehicle 610 occurs prior to the favorable energy supply, due to the relatively short time interval between the energy intake and the energy release, the simultaneous occurrence of the charging cycle and the discharging cycle of the energy storage module 110 equipped with the battery 515 is avoided, so the increase in the internal energy consumption of the flywheel generator 115 is not very relevant. Therefore, by using the flywheel generator 115 when the time difference between the intake and release of a relatively large amount of energy is short, the battery 515 of the energy storage system 501 can be conserved, thereby extending its lifespan. Accordingly, in the scenario on the left side of FIG. 6, the energy storage module 110 equipped with the battery 515 is stopped from operating as shown by the dotted outline of that module.

[0078] However, in another scenario illustrated on the right side of FIG. 6, different from the scenario illustrated on the left side of FIG. 6, this control device 121 determines that, for example, an energy supply is surely obtained by the solar power generation facility or by the night-time power in the power grid (as indicated by the symbol 620 regarding night-time power), but on the other hand, during a longer time period, a small amount of energy should be taken out from the energy storage system 501 or no energy should be taken out at all.

[0079] Therefore, under such scenarios or operating conditions of the energy storage system 501 as shown on the right side of FIG. 6, this control device 121 determines to use the power storage modules 110 each equipped with a battery 515 to capture energy. Using the power storage modules 110 equipped with the batteries 515, similar to the case of long-term energy storage by the flywheel generator 115, the internal energy consumption of the power storage modules 110 equipped with the batteries 515 can capture and then store a certain amount of energy over a longer period without having an adverse effect on the overall energy balance of the energy storage system 501.

[0080] Therefore, as also indicated by the dotted line, while the power storage module 110 equipped with the battery 515 is capturing energy, the operation of the power storage module 110 equipped with the flywheel generator 115 remains stopped. Thereby, the overall internal energy consumption of the energy storage system 501 is minimized.

[0081] The control device 121 of the energy storage systems 101 and 501 can use different algorithms, artificial intelligence, databases, and combinations thereof to preferably control the energy flow among the power storage modules 110 of the energy storage systems 101 and 501, and the energy flow captured by the energy storage systems 101 and 501 and taken out therefrom for the current time point and future time periods. Thereby, overall, the internal energy consumption of the energy storage systems 101 and 501 can be minimized and the operating rate of the energy storage systems 101 and 501 can be improved.

[0082] Furthermore, for example, by optimizing the internal energy balance, it is possible to avoid frequent occurrences of processes such as the charge-discharge cycle of the battery 515 that may have an adverse effect on the life of a predetermined power storage module 110 of the energy storage systems 101, 501. Therefore, by suitable control using the control device 121, the life of the energy storage systems 101, 501 can be extended as a whole. In some cases, in addition to monitoring and predicting the internal parameters of each power storage module 110 that can include multiple module types, this control device 121 can further identify the supply and demand regarding the amount of energy to be taken in or taken out from the energy storage systems 101, 501 for a future time period, and control the power storage module 110 accordingly, as described above based on the different examples in FIGS. 5 and 6.

[0083] Furthermore, the control device 121 of the energy storage systems 101, 501 can identify an external energy storage device and its operating rate in a predetermined future time period, and incorporate such an external device, for example, the battery of an electric vehicle, as a temporary power storage machine into the energy balance of the energy storage systems 101, 501. This control device 121 can communicate and connect with different external devices to identify the current operating conditions and possible future operating conditions of the energy storage systems 101, 501. As a result, such external devices transmit information regarding the parameters of external devices that can request the extraction of energy from the energy storage systems 101, 501 or provide the supply of energy to the system, and information regarding future energy supply or future energy demand to the control device 121.

Explanation of Reference Numerals

[0084] 100 Energy storage system according to the prior art 101 Energy storage system according to the present invention 110 Power storage module 111 Selected first power storage module 112 Selected second power storage module 113 Selected third power storage module 115 Flywheel power generator 120 Control device according to the prior art 121 Control device according to the present invention 130 Energy holding amount of each power storage module 135 Residual energy holding amount 137 Increased energy holding amount 140 Block arrow 300 Vacuum system 310 Vacuum pump 311, 312 Vacuum pumps whose operations have been stopped 400 Vacuum system 410 Vacuum pump 415 Rotation speed measuring device 501 Energy storage system according to the present invention 515 Battery 610 Electric vehicle 620 Symbol related to night power

Claims

1. An energy storage system (101, 501) including a plurality of storage modules (110) and one control device (121), This control device is Identifying operating conditions of the energy storage system (101, 501) for a predetermined period of time; selecting one of the plurality of storage modules (110) depending on the specified operating conditions of the energy storage system (101, 501) and depending on at least one internal parameter of each of the plurality of storage modules (110); determining whether the selected storage module (110) will take in energy, release energy, or cease operation based on the identified operating conditions of the energy storage system (101, 501) and based on at least one internal parameter of the selected storage module (110); 1. An energy storage system configured as follows:

2. 2. The energy storage system (101, 501) of claim 1, The control device (121) is further configured to determine, based on the specified operating conditions of the energy storage system (101, 501) and based on at least one internal parameter of the selected storage module (110), whether another storage module (110) of the storage system (101, 501) will absorb the amount of energy released from the selected storage module (110) or whether the energy storage system (101, 501) will release the amount of energy released from the selected storage module (110) to an external device.

3. The energy storage system (101, 501) according to claim 1 or 2, The energy storage system, wherein the at least one internal parameter of the storage modules (110) includes an energy reserve of each storage module (110).

4. The energy storage system (101, 501) according to any one of claims 1 to 3, The specified operating conditions are assigned amounts of energy to be supplied to or drawn from the energy storage system (101, 501) within a predetermined period of time.

5. The energy storage system (101, 501) according to any one of claims 1 to 4, The control device (121) is further configured to determine operating conditions of the energy storage system (101, 501) based on a state of an external device, the external device being connected to the energy storage system (101, 501) and configured to transmit energy to the external device.

6. The energy storage system (101, 501) according to any one of claims 1 to 5, The control device (121) is further configured to determine operating conditions of the energy storage system (101, 501) based on parameters of an external device, and the energy storage system (101, 501) is connectable to the external device to transfer energy to the energy storage system (101, 501).

7. The energy storage system (101, 501) according to any one of claims 1 to 6, The control device (121) is further configured to control the multiple storage modules (110) so that only the selected storage module (110) releases energy until the energy reserve (130) of the selected storage module (110) falls below a predetermined threshold, while the other storage modules (110) do not release energy and the operation of the selected storage module (110) is stopped when the energy reserve (130) falls below a predetermined threshold.

8. The energy storage system (101, 501) according to any one of claims 1 to 7, The storage module (110) includes at least two different module types (115, 515); a storage module (110) of a first module type (115) configured to draw energy up to a first remaining energy reserve; a storage module (110) of a second module type (515) configured to draw energy up to a second remaining energy reserve; the first amount of remaining energy is less than the second amount of remaining energy; Energy storage systems.

9. 9. The energy storage system (101, 501) according to claim 8, the storage module (110) of the first module type (115) has a first internal energy consumption; the storage module (110) of the second module type (515) has a second internal energy consumption; The first internal energy consumption is greater than the second internal energy consumption; Energy storage systems.

10. The energy storage system (101, 501) according to claim 7 or 8, The storage module (110) of the first module type is configured as a flywheel storage machine (115); The second module type storage module (110) is configured as a battery (515); Energy storage systems.

11. The energy storage system (101, 501) according to any one of claims 1 to 10, An energy storage system, wherein at least one storage module (110) is configured as a flywheel storage (115).

12. 12. The energy storage system (101, 501) according to claim 11, The flywheel electric accumulator (115) includes a magnetic bearing and a vacuum device (300, 400); The control device (121) is further configured to stop operation of the magnetic bearing and at least partially stop the vacuum device (300, 400) while the flywheel electric storage machine (115) is stopped.

13. 13. An energy storage system (101, 501) according to claim 11 or 12, At least one other storage module (110) configured as a battery (515); The control device (121) further comprises: Controlling the storage module (110) to transfer the energy reserve (130) of the flywheel storage unit (115) from the storage unit to a battery (515) when the energy reserve (130) of the flywheel storage unit (115) falls below a predetermined threshold; Next, the operation of the flywheel electric storage machine (115) is stopped.

1. An energy storage system configured as follows:

14. The energy storage system (101, 501) according to any one of claims 1 to 13, The control device (121) further comprises: identifying a first time point after which the energy storage system (101, 501) should capture a first amount of energy; identifying a second point in time after which the energy storage system (101, 501) should release a second amount of energy; The energy storage system is configured to determine whether to allow the flywheel electric machine (115) or the battery (515) to release the second amount of energy after capturing the first amount of energy based on a time difference between the first and second points in time, based on the first amount of energy, and based on the second amount of energy.

15. A method of operating an energy storage system (101, 501) having a plurality of storage modules (110) and a control device (121), comprising: Identifying an operating condition of an energy storage system (101, 501) for a predetermined period of time; selecting one of the plurality of storage modules (110) depending on specified operating conditions of the energy storage system (101, 501) and depending on at least one internal parameter of each of the plurality of storage modules (110); determining whether the selected storage module (110) will take in energy, release energy, or stop operating based on the identified operating conditions of the energy storage system (101, 501) and based on at least one internal parameter of the selected storage module (110); The method according to claim 1,

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