P2024,0048 WO E /P230173WO01 March 28,2024 -1 - Description ENERGY STORAGE SYSTEM,METHOD FOR ELECTRICALLY ISOALTING AT LEAST ONE STORAGE MODULE SYSTEM AND METHOD FOR TRSAFNERRING ENERGY The present disclosure relates to an energy storage system, a method for electrically isolating at least one ener gy storage module in an energy storage system and a method for transferring energy from at least one energy storag e module to at least one other energy storage module in an e nergy storage system. Typically, energy storage systems play a crucial ro le in ensuring stability and reliability of electrical po wer grids with renewable energysystems. Embodiments of the disclosure relate to an energy s torage system which has an improved functionality. Further embodiments relate to methods for operation of such an energy storage system. This is achieved by the subject-matter of the indep endent claims. Further embodiments are evident from the de pendent claimsand the following description. An energy storage system is described. Exemplarily, the energy storage system is connected to an electrical power grid. In particular, the energy storage system is c onfigured to reduce energy imbalances of the electrical power grid. In particular, the energy storage system is configured to receive an electrical current from the electrical p ower grid
P2024,0048 WO E /P230173WO01 March 28,2024 -2 - aswellasto provide an electricalcurrentto the electrical powergrid. According to an embodiment, the energy storage syst em comprises an energy storage string with energy stor age modules connected in series through current breakin g elements. Exemplarily, the energy storage string is connected to a power transmission system connected to the ele ctrical power grid and connected to an energy source and/or an energy load. For example, the energy storage string is arr anged between the power transmission system and an electr ical reference potential, which is, in particular, a gro und potential,i.e.,a ground. The energy storage modules are each configured to r eceive an electrical current from the power transmission syst em as well as to provide an electrical current to the power tr ansmission system, in particular independently from one anothe r. Exemplarily, each of the energy storage modules com prises an energystorage block.The energystorage blockis, for example,an electricalenergyaccumulatorwhich is configured to store and release electric energy. The energy st orage block is, for example, at least one of a battery mo dule and a supercapacitor. The energy storage block comprises, for example, at least two terminals, a first terminal a nd a second terminal. In particular, the terminals diffe r from one another in their polarity. If the energy storage is a battery, the terminals comprise an anode terminal a nd a cathode terminal. If the energy storage is a superc apacitor, the terminals comprise a positive terminal and a ne gative terminal.
P2024,0048 WO E /P230173WO01 March 28,2024 -3 - The energy storage block can further comprise elect rical storage cells being connected to one another. For e xample, the electrical storage cells are connected in serie s and/or in parallelto one another. For example, directly neighbouring energy storage m odules are connected to one another with a connection, wherein the connection is formed exemplarily by a wire, a busba r and/or a connector. In particular, each connection electrica lly connects the first terminal and the second terminal of directly neighbouring energy storage modules with o ne another. The current breaking elements are exemplar ily arranged between directly neighbouring energy stora ge modules atthe respective connection. For example, each current breaking element is confi gured to disconnect directly neighbouring energy storage mod ules from one another. In particular, the current breaking el ement is configured to transmit electrical current between d irectly neighbouring energy storage modules when the curren t breaking elementisin the closed state.In particular,the current breaking element is configured to interrupt electri cal current between directly neighbouring energy storag e modules when the current breaking element is in an open sta te. Exemplarily, the state of the current breaking elem ent is dependent on an electrical current which is applied to the currentbreaking element. According to the embodiment, the energy storage sys tem comprises a parallel line with switches being conne cted in series. Exemplarily, a number of energy storage mod ules equals a number of switches, such that one of the s witches and one of the current breaking elements are connec ted to one
P2024,0048 WO E /P230173WO01 March 28,2024 -4 - respective energystorage module.Alternatively,a numberof energy storage modules is larger than a number of s witches, such that at least two of the switches and/or at le ast two of the currentbreaking elementsare connected to one respective energystorage module. For example, directly neighbouring switches are con nected to one another with an interconnection. Exemplarily, e ach interconnection is electrically connected to a resp ective connection connecting directlyneighbouring energy storage modules. The switches are exemplarily formed of a m echanical switch and/or an electrical switch or a combination thereof. Exemplarily, the switch is operated with an externa l control device. In particular, the switch is configured to transmit electrical current when the switch is in the closed state. In particular, the switch is configured to interrupt e lectrical currentwhen the switch isin an open state. According to the embodiment of the energy storage s ystem, each energy storage module is connected to one of t he current breaking elements. Exemplarily, at least one energy storage module is connected to exactly one of the current b reaking elementsand/orto exactlyone ofthe switches.In particular, exactly one current breaking element an d/or exactly one switch is assigned to at exactly one en ergy storage module. Exemplarily, the connection connect ing directly neighbouring energy storage modules compri ses exactlyone currentbreaking element. For example, at least two energy storage modules ar e connected to exactly one of the current breaking el ements
P2024,0048 WO E /P230173WO01 March 28,2024 -5 - and/or to exactly one of the switches. In particula r, exactly one current breaking element and/or exactly one swi tch is assigned to at more than one neighboring energy sto rage modulesconnected in series. According to the embodiment of the energy storage s ystem, each switch is connected in parallel with a respect ive energy storage module and a respective current breaking el ement. Exemplarily, exactly one switch is connected in par allel with exactly one respective energy storage module connec ted to exactlyone currentbreaking element. According to the embodiment of the energy storage s ystem, the respective switch is configured to provide a curren t path through the respective energy storage module and th e respective current breaking element. Exemplarily, t he current breaking element is controlled dependent on a state of the switch. The switch is, for example, configured to g enerate an artificial short circuit current when in the closed state. In particular, if the switch is in the closed state, t he energy storage module is shortened by the respective energ y storage module and the respective interconnection in partic ular by the artificialshortcircuitcurrent. Exemplarily, the state of the current breaking elem ent is dependent on an electrical current, which is applie d to the current breaking element. Exemplarily, if an accumu lated value of the artificial short circuit current is hi gher than a threshold value,the respective currentbreaking elementis configured to be in the opened state,particularly disconnecting directlyneighbouring energystorage modules from one another. Exemplarily, the accumulated valu e can be preset to be higher than the threshold value by clo sing the
P2024,0048 WO E /P230173WO01 March 28,2024 -6 - switch. The threshold value is, for example, charac teristic of a breaking current limit of the current breaking element. If the accumulated value of the artificial short ci rcuit current is smaller than the threshold value, the re spective current breaking element is configured to be in the closed state, particularly connecting directly neighbourin g energy storage modules to one another. Exemplarily, the ac cumulated value can be preset to be smaller than the threshol d value depending on closing and opening the switch with a preset frequency. According to the embodiment of the energy storage s ystem, the respective switch isconfigured to allow a current flow through the respective currentbreaking elementto disconnect and bypass the respective energy storage module fro m the energystorage string.In particular,ifdirectly neighbouring energy storage modules are disconnecte d by the respective currentbreaking element,the switch is configured to be in the closed state,in particularto bypass the respective energystorage module. Advantageously,with such an energystorage system a faulty energy storage module can be isolated and bypassed, thereby allowing continuousoperation ofthe otherhealthy energy storage modules. A balancing of energy can advantag eously be implemented among neighbouring energy storage modul es, leading to an optimal use of the available energy s torage modules’ capacity. This avoids unnecessary oversizi ng of the energystorage system. Particularly, with such an energy storage system, a lifetime of the energy storage modules can be maximised, and an
P2024,0048 WO E /P230173WO01 March 28,2024 -7 - accelerated aging of the energy storage modules can be minimized by the energy balancing. In particular, t his leads to reduced energy losses and lower operating expens es due to the active energyredistribution. According to a further embodiment of the energy sto rage system, each switch is connected to one of the curr ent breaking elements by an impedance line. The impedan ce line is,forexample,comprised bythe interconnection. Exemplarily, the interconnection and/or the impedan ce line is formed bya wire,a busbarand/ora connector. Exemplarily, at least some of the impedance lines a re each solely characteristic of an impedance of the connec tion and the interconnection. Alternatively or additionally, at least some of the impedance lines comprise an inductor. Exemplarily, at least s ome of the impedance lines are each characteristic of the impe dance of the connection, the interconnection, and the induct or. According to a further embodiment of the energy sto rage system, at least one current breaking element is co nfigured to electrically isolate the respective energy stora ge module dependent on a first operational mode of the respec tive switch.Exemplarily,the firstoperationalmode is characteristicofclosing the switch such thatthe accumulated value of the artificial short circuit c urrent is higherthan the threshold value and the respective current breaking elementisopened. According to a further embodiment of the energy sto rage system, the impedance lines are configured to trans fer energy
P2024,0048 WO E /P230173WO01 March 28,2024 -8 - from the respective energy storage module to direct ly neighboring energy storage modules dependent on a s econd operational mode of the respective switch. Exemplar ily, the second operational mode is characteristic of closin g and opening the switch with a preset frequency such tha t the accumulated value is smaller than the threshold val ue. For example, the second operational mode is characteris tic of a pulse width modulation of a driving signal of the s witch, particularly characteristic of the closing and open ing of the switch. According to a further embodiment of the energy sto rage system, each current breaking element is arranged o n a connection between the respective energy storage mo dule and the respective switch. According to a further embodiment of the energy sto rage system, the switch is a power semiconductor switch. The power semiconductor switch comprises, for example, a Meta l-Oxide- Semiconductor Field-Effect Transistor, MOSFET, and/ or an Insulated Gate BipolarTransistor,IGBT. Advantageously, by using power semiconductor switch es, the comparatively rapid switching of the second operati onal mode, in particularwith minimallosses,isachieved. According to a further embodiment of the energy sto rage system, at least some of the current breaking eleme nts comprise a fuse. Exemplarily, the fuse is configure d to open, e.g.being operated in the opened state,dependent on an overcurrent event. The overcurrent event is in part icular characteristic of the accumulated value of the arti ficial short circuit current being higher than the thresho ld value.
P2024,0048 WO E /P230173WO01 March 28,2024 -9 - In particular, the fuse automatically opens depende nt on the overcurrent event. “Automatically” means here and i n the following that the current breaking element is conf igured to open dependent on the current flowing through the c urrent breaking element. If the current breaking element is formed as a fuse , advantageously, solely the switch has to be operate d actively, e.g. by the external control device. This advantageously is comparatively communication resou rce- saving. According to a further embodiment of the energy sto rage system, at least some of the current breaking eleme nts comprise an isolation switch. The isolation switch, for example, is configured to open, e.g. being operated in the opened state,dependenton the overcurrentevent automatically or manually. “Manually” means here an d in the following that the current breaking element is conf igured to open dependenton a controlsignalprovided to the current breaking elementfrom an externalcontroldevice. According to a further embodiment of the energy sto rage system, at least some of the impedance lines compri se an inductor. Exemplarily, all impedance lines comprise an inductor. According to a further embodiment, the energy stora ge system further comprises a further parallel line with furt her switchesbeing connected in series.In particular, the further parallel line is connected in parallel to t he parallelline.
P2024,0048 WO E /P230173WO01 March 28,2024 -10 - According to a further embodiment of the energy sto rage system, each further switch is connected in paralle l with a respective energy storage module and a respective c urrent breaking element. For example, directly neighbourin g further switches are connected to one another with a furthe r interconnection. Exemplarily, each further intercon nection is electricallyconnected bya furtherimpedance line to a respective connection connecting directly neighbour ing energy storage modules. According to a further embodiment of the energy sto rage system,each furtherswitch isconnected to one of the current breaking elements by a further impedance li ne. According to a further embodiment of the energy sto rage system, at least some of the further impedance line s comprise a furtherinductor. According to a further embodiment of the energy sto rage system, every second impedance line comprises the i nductor, every second further impedance line comprises the f urther inductor, and the impedance line comprises the indu ctor if the further impedance line comprises no further ind uctor. According to a further embodiment of the energy sto rage system, a resistor is arranged between two connecti ons of one energy storage module. Exemplarily, at least some a nd or all connections are connected to the resistor. In parti cular, each resistor is arranged between two connections c onnected to the firstterminaland the second terminalofa respective single energystorage module.
P2024,0048 WO E /P230173WO01 March 28,2024 -11 - According to a further embodiment of the energy sto rage system, a resistor module is connected to the switc h. In particular, a resistor module is connected to at le ast some ofthe switchesorallofthe switches. According to a further embodiment of the energy sto rage system, the resistor module comprises a resistor an d a bypass switch. According to a further embodiment of the energy sto rage system,the resistormodule isconnected in series to the switch, and the bypass switch is arranged in parall el to the resistor. In particular, the bypass switch is confi gured in this embodiment to bypass the resistor when the byp ass switch isin an opened state. According to a further embodiment of the energy sto rage system, the resistor module is connected in paralle l to the switch, and the bypass switch is arranged in series to the resistor. In particular, the bypass switch is confi gured in this embodiment to bypass the resistor when the byp ass switch isin a closed state. Advantageously, the resistors are used to discharge the respective energy storage module to a voltage level which is safe to handle. According to a further embodiment, the energy stora ge system further comprises a further energy storage string c onnected in parallel to the energy storage string. The furth er energy storage string is embodied as the energy storage st ring described herein before. Additionally, the energy s torage
P2024,0048 WO E /P230173WO01 March 28,2024 -12 - system can comprise a plurality of further energy s torage stringsconnected in parallelto one another. Advantageously,the switchesofthe energystorage string and the further energy storage string are used to suppr ess circulating currents among parallelly connected ene rgy storage strings by ensuring a voltage balancing amo ng the parallelenergystorage strings. A further embodiment relates to a method for electr ically isolating atleastone energystorage module in an energy storage system, in particular an energy storage sys tem described herein above.Therefore,the featuresas described in connection with the method are also applicable f or the energystorage system and vice versa. According to an embodiment of the method, the switc h connected to the at least one energy storage module is closed, such that an artificial short current is ge nerated. According to an embodiment of the method, the curre nt breaking element connected to the at least one ener gy storage module is triggered dependent on the artificial sho rt current,such thatthe atleastone energystorage module is electrically isolated from the other energy storage modules. According to a further embodiment of the method, th e switch is closed dependent on a monitoring information. Th e monitoring information comprises, for example, a st ate information of the respective energy storage module . The state information comprises, for example, a state o f charge, a state of health and/or a temperature. If the moni toring information is indicative of an energy storage modu le which
P2024,0048 WO E /P230173WO01 March 28,2024 -13 - does not function normally, the switch is closed in ducing the artificialshortcurrent. Exemplarily, the external control device is configu red to monitor the monitoring information and is further c onfigured to operate the respective switch dependent on the m onitoring information. A further embodiment relates to a method for transf erring energy from at least one energy storage module to a t least one other energy storage module in an energy storag e system, in particular an energy storage system described he rein above. Therefore, the features as described in conn ection with the method are also applicable forthe energy storage system and vice versa. According to an embodiment of the method, the switc h connected to the at least one energy storage module is closed for a time interval, such that electric energy of t he at least one energy storage module is stored in the re spective impedance line. According to an embodiment of the method, the switc h of the atleastone energystorage module isopened,such that electricenergyofthe atleastone energystorage module is released from the respective impedance line to the atleast one other energy storage module. Exemplarily, the s witch of the at least one energy storage module is opened fo r a furthertime intervalsuch thatelectricenergyof the at least one energy storage module is released from th e respective impedance line to the at least one other energy storage module.
P2024,0048 WO E /P230173WO01 March 28,2024 -14 - Exemplarily, the switch connected to the at least o ne energy storage module is closed and opened with the preset frequency. This means that the time interval and th e further time interval are subsequent to one another and alt ernate with one another. According to a further embodiment of the method, th e time interval is determined such that an accumulated val ue of the artificial short current is smaller than a threshol d value. The accompanying Figuresare included to provide a further understanding. In the Figures, elements of the same structure and/orfunctionalitymaybe referenced bythe same reference signs.Itisto be understood thatthe embodiments shown in the Figures are illustrative representations and ar e not necessarilydrawn to scale. Figure 1 schematically shows an energy storage syst em according to an exemplaryembodiment. Figure 2 schematically shows a part of an energy st orage system according to an exemplaryembodiment. Figures 3 and 4 schematically show a method for ope rating an energy storage system according to an exemplary emb odiment. Figure 5 schematically shows an energy storage syst em according to an exemplaryembodiment. Figures 6, 7, 8 and 9 schematically show a method f or operating an energystorage system according to an exemplary embodiment.
P2024,0048 WO E /P230173WO01 March 28,2024 -15 - Figures 10, 11, 12, 13 and 14 each schematically sh ow an energy storage system according to an exemplary emb odiment. The energy storage system 1 according to the exempl ary embodimentofFigure 1 comprisesan energystorage string 2 with energy storage modules 3 connected in series t hrough current breaking elements 6. For example, the energ y storage string 2 is arranged between a power transmission s ystem and a reference potential.On a side facing the power transmission system, an energy storage system isola tor switch 14 is arranged for electrically isolating the energ y storage string 2 as a whole. A string current 13 is indicat ed, wherein the arrow in Figure 1 ischaracteristicof the current flowing from the energy storage string 2 to the power transmission system. Each energy storage module 3 is connected to one of the current breaking elements 6. Each energy storage mo dule 3 comprises a first terminal 4 indicated with a “-” p olarity in Figure 1 and a second terminal 5 indicated with a “ +” polarityin Figure 1.Directlyneighbouring energy storage modules 3 are connected to one another with a conne ction 7, wherein each connection 7 electrically connects a f irst terminal 4 and a second terminal 5 of directly neig hbouring energy storage modules 3. Each connection 7 compris es one of the current breaking elements 6. Each of the curren t breaking elements6 isparticularlyformed asa fuse. The energy storage system 1 further comprises a par allel line with switches 9 being connected in series. Each swi tch 9 is connected in parallel with a respective energy stor age module 3 and a respective current breaking element 6. Dire ctly neighbouring switches 9 are connected to one anothe r with an
P2024,0048 WO E /P230173WO01 March 28,2024 -16 - interconnection 10. Each interconnection 10 is elec trically connected to a respective connection 7 connecting d irectly neighbouring energy storage modules 3 by an impedan ce line 11. Particularly, the impedance line 11 further com prises an inductor 12. The inductor 12 is, for example, reali zed by a discrete inductor or by a magnetic core arranged ar ound the impedance line 11. Advantageously, such an inductor 12 is a saturable inductor, offering a negligible impedance at comparativelyhigh currents. A respective switch 9 is configured to provide a cu rrent path through the respective energystorage module 3 and the respective current breaking element 6, and the resp ective switch 9 is configured to disconnect the respective energy storage module 3 from the energystorage string 2, as descried in more detail in connection with Figure 2 and/or Figures3 and 4. Advantageously, a combination of the current breaki ng element 6 formed as a fuse and a switch 9 is used for elect rical isolation and bypassing a faulty energy storage mod ule 3. Particularly, the fuse is triggered by a state of t he switch 9.Additionally,such an energystorage system 1 advantageously ensures a voltage balancing by redis tributing energy among at least some of the energy storage mo dules 3 connected in series. The current breaking element 6 formed as a fuse acc ording to the exemplaryembodimentofFigure 2 isconfigured to be operated to be in the opened state, e.g. operated t o melt, dependent on a state of the switch 9. When the swit ch 9 is in the closed state, the energy storage module 3 is sh ortened through the fuse and the impedance lines 11 of a cl osed path.
P2024,0048 WO E /P230173WO01 March 28,2024 -17 - This means that an artificial short circuit current is generated when the switch 9 is in the closed state. An impedance of the closed path is in particular a com bination of an internal impedance of the energy storage modu le 3 and an externalimpedance,e.g.from the connection 7, the interconnection 10 and the impedance line 11 partic ularly comprising the inductor12. When the current breaking element 6 is in the opene d state, the switch 9 remainsin the closed state to bypass a respective faulty energy storage module 3. Advantag eously, a continued operation ofthe energystorage string 2 isthus achieved – with reduced capacity. The artificial short circuit current is exemplarily solely dependent on a voltage of the energy storage module 3 and the impedance ofthe closed path.Advantageously,such an artificialshortcircuitcurrentvariesonlyin a comparatively small range. Therefore, a tight contr ol over a clearing time is advantageously achieved. Typically , for normal fuses it takes a long time to clear a faulty energy storage module 3 when a fault current is low. Howev er, with such an energy storage system 1, once the faulty en ergy storage module 3 is detected, the faulty energy sto rage module 3 can be cleared comparatively fast by gener ating the artificialshortcircuitcurrent. Exemplarily, the switch 9 and thus the current brea king element 6 are operated dependent on a temperature o f the energy storage module 3. As an overheating of the e nergy storage module is an early sign of degradation, i.e . being indicative of the faulty energy storage module 3, t he temperature of the energy storage module 3 is monit ored and
P2024,0048 WO E /P230173WO01 March 28,2024 -18 - the state ofthe switch 9 isoperated dependenton a temperature ofthe energystorage module 3.This advantageously triggers the current breaking elemen t 6 for isolating the respective energy storage module 3 be fore catastrophicfailure. As the artificial short circuit current varies only in a comparatively small range, the current breaking ele ment 6 formed as a fuse can be selected with a required mi nimum breaking capacityparticularlyeasy.Further,asa same amount of the artificial short circuit flows throug h the energy storage module 3 and the current breaking el ement 6, a breaking currentofthe currentbreaking element6 can be advantageously selected to break the current to avo id severe heating of the energy storage module 3 and the swit ch 9. The switches 9 of the energy storage system 1 accor ding to Figures 3 and 4 are formed of power semiconductor s witches 9, such asMOSFETs orIGBTs.Particularly,the energy storage system 1 corresponds to the energy storage system 1 described in connection with Figure 1. For example, each of t he power semiconductor switches 9 intrinsically comprises an anti- parallel diode 15. Advantageously, for an energy ba lancing between the energystorage modules3,the switches 9 can be operated in a modulated manner to avoid the current breaking element 6 to be triggered to switch to the opened s tate. Thus, the switches 9 are formed of comparatively fa st bidirectional switches, i.e. the power semiconducto r switches. The energystorage string 2 comprises,interalia, a first energy storage module 3, a second energy storage mo dule 3 and a third energystorage module 3.The second energy storage
P2024,0048 WO E /P230173WO01 March 28,2024 -19 - module 3 is directly adjacent to the first energy s torage module 3 and the third energy storage module 3, i.e . the second energy storage module 3 is arranged in serie s between the first energy storage module 3 and the third ene rgy storage module 3. Exemplarily, the second energy st orage module 3 is degraded more than the first energy sto rage module 3 and the third energy storage module 3. For example, due to thisdegradation,the second energystorage module 3 experiences more capacity loss and a higher equival ent series resistance compared to the other energy storage mod ules 3. This results, e.g. during a charging process, in th at a voltage of the second energy storage module 3 rises at a faster rate than a voltage of the other energy stor age modules 3, e.g. reaching the maximum permissible vo ltage. At the same time, the other energy storage modules 3 a re undercharged, leading to an underutilization of the capacity ofthe energystorage system 1. For transferring energy from the second energy stor age module 3, being particularly overcharged, to the first and third energy storage modules 3, initially, the switch 9 i s operated to be in the closed state for establishing a curren t path as indicated in Figure 3. In particular, energy of the second energy storage module 3 is stored in the respective inductors 12. Particularly, the switch 9 corresponding to the fau lty second energy storage module 3 is closed for a time interv al. The time interval is determined such that an accumulate d value of the artificial short current is smaller than a thre shold value, wherein the threshold value is, for example, characteristic of a breaking current limit of the c urrent breaking element6.
P2024,0048 WO E /P230173WO01 March 28,2024 -20 - Subsequently,asindicated in Figure 4,the switch 9 ofthe second energy storage module 3 is opened for a furt her time interval, such that electric energy of the at least one energy storage module 3 is released from the respec tive impedance line 11 to the atleastone otherenergy storage module 3. Once the switch 9 is in the opened state, an induct or current isfreewheeled through the anti-paralleldiodes15 ofthe switches 9 corresponding to the first and third ene rgy storage modules3. Exemplarily, as the energy is transferred to the tw o directly neighboring energy storage modules 3, e.g. to the f irst and third energystorage modules3,partofthe energy is transferred back and forth before a balancing is ac hieved. In contrast to the energy storage system 1 accordin g to Figure 1,the energystorage system 1 according to Figure 5 comprises a further parallel line with further swit ches 17 being connected in series, wherein each further swi tch 17 is connected in parallel with a respective energy stor age module 3 and a respective current breaking element 6. Each further switch 17 is connected to one of the current breaki ng elements 6 by a further impedance line 19. In parti cular, every second impedance line 11 comprises the induct or 12, every second further impedance line 19 comprises th e further inductor 20, and the impedance line 11 comprises th e inductor 12 if the further impedance line 19 comprises no fu rther inductor20.
P2024,0048 WO E /P230173WO01 March 28,2024 -21 - Exemplarily, for achieving a comparatively fast bal ancing compared to the energy storage system 1 of Figure 1 , the energy storage system 1 of Figure 5 particularly ha s a parallel connection of bidirectional switches, i.e. being the switches9 and the furtherswitches17. In connection with Figures 6 and 7, a transfer of e nergy is described from the second energy storage module 3 t o the first energy storage module 3, and in connection wi th Figures 8 and 9, a transfer of energy is described from the second energy storage module 3 to the third energy storage module 3, particularly using the energy storage system 1 acco rding to Figure 5. In Figure 7, the switch 9 corresponding to the seco nd energy storage module 3 is in the closed state such that e nergy is transferred from the second energy storage module 3 to the respective inductor12.In Figure 8,the switch 9 corresponding to the second energy storage module 3 is in the opened state such that energy is transferred from t he respective inductor12 to the firstenergystorage module 3. In Figure 9, the further switch 17 corresponding to the second energy storage module 3 is in the closed sta te such that energy is transferred from the second energy s torage module 3 to the respective furtherinductor20.In Figure 8, the further switch 17 corresponding to the second e nergy storage module 3 is in the opened state such that e nergy is transferred from the respective further inductor 20 to the second energystorage module 3.
P2024,0048 WO E /P230173WO01 March 28,2024 -22 - Advantageously, as energy is transferred to only on e directly neighboring energy storage module 3, balancing is a chieved comparativelyfast. In contrast to the energy storage system 1 accordin g to Figure 1, the current breaking element 6 of the ene rgy storage system 1 according to Figure 10 is formed a s an isolation switch 9. In contrast to the energy storage system 1 accordin g to Figure 1,the energystorage system 1 according to Figure 11 further comprises a resistor 21. The resistor 21 is arranged between two connections 7 of one energy storage mod ule 3. Further, the impedance lines 11 in Figure 11 do not comprise the inductor12. Particularly, the resistors 21 are configured to di ssipate energy of the respective energy storage module 3 wi th excess voltage. The resistors 21 are exemplarily used to d ischarge the respective energy storage module 3 to a voltage level which issafe to handle. The impedance lines 11 in Figure 12 do not comprise the inductor12 asdescribed in Figure 1. The energy storage systems 1 according to Figures 1 3 and 14 comprise,in contrastto the energystorage system 1 according to Figure 1, a resistor module 22. The re sistor module 22 is connected to the switch 9, and the res istor module 22 comprises a resistor 21 and a bypass swit ch 23. In Figure 13, the resistor module 22 is connected i n series to the switch 9, and the bypass switch 23 is arrang ed in
P2024,0048 WO E /P230173WO01 March 28,2024 -23 - parallel to the resistor 21. In Figure 14, the resi stor module 22 is connected in parallel to the switch 9, and the bypass switch 23 is arranged in series to the resis tor 21.
P2024,0048 WO E /P230173WO01 March 28,2024 -24 - Reference Signs 1 energystorage system 2 energystorage string 3 energystorage module 4 firstterminal 5 second terminal 6 currentbreaking element 7 connection 8 parallelline 9 switch 10 interconnection 11 impedance line 12 inductor 13 string current 14 energystorage system isolatorswitch 15 anti-paralleldiode 16 furtherparallelline 17 furtherswitch 18 furtherinterconnection 19 furtherimpedance line 20 furtherinductor 21 resistor 22 resistormodule 23 bypassswitch