Charging system having liquid-cooling system for multiple electric vehicles

Abstract

A charging system (10) for charging electric vehicles is provided which comprises a grid interface (GI), a multitude of converter modules (Cm) connected to the grid interface (GI), a reconfiguration switch (S), a multitude of dispensers (Dn) connected to the multitude of converter modules (Cm) via the reconfiguration switch (S), and a liquid-cooling system (CS). The converter modules (Cm) are flexibly assigned to the dispensers (Dn) via the reconfiguration switch (S) for adjusting different charging-power needs of the dispensers (Dn). A total installed current capacity of the converter modules (Cm) is lower than a total installed current capacity of the dispensers (Dn). The dispensers (Dn) are fluidly connected in a cooling loop of the liquid-cooling system (CS). The liquid-cooling system (CS) comprises a central cooler (CC) and a central pump (CP). A maximum cooling power of the liquid-cooling system (CS), for which the central cooler (CC) is dimensioned, is adapted to a maximum of ohmic losses in the dispensers (Dn) generated with the total installed current capacity of the converter modules (Cm).

Description

[0001] P2023,0648 WO E / P230038WO01 July 31, 2023 - 1 - Description CHARGING SYSTEM HAVING LIQUID-COOLING SYSTEM FOR MULTIPLE ELECTRIC VEHICLES The present disclosure relates to a charging system having a liquid-cooling system for multiple electric vehicles. A charging system for concurrent charging of the batteries of multiple electric vehicles (EVs) may be built in a modular way and can comprise a plurality of converter modules which are connected flexibly to a plurality of dispensers for instance via a reconfiguration switch. This allows to satisfy the different needs of charging power, current, and voltage of the different EVs. Both the converter modules and the dispensers have their power and current limits, usually due to temperature limits. So far, in many conventional charging systems for the concurrent charging of multiple EVs, it has been suggested to over-dimension a cooling system of the charging system in terms of cooling power. The over- dimensioning of the cooling system, however, results in high cost, size, and volume of the cooling system. Thus, it is desirable to reduce the cost and size of the charging system while maintaining the flexibility and efficiency of the charging system, in particular the flexibility and efficiency of the cooling system of the charging system. One embodiment of this disclosure, as claimed in the independent claim, addresses the above shortcomings in the art in whole or in part. Further embodiments of the charging system are subject matter of the further claims. P2023,0648 WO E / P230038WO01 July 31, 2023 - 2 - It has been found that statistically, it is not often that all dispensers of a charging system are connected at the same time to different EVs that request the maximum admissible current of the dispensers. Therefore, for reducing the investment cost, it is suggested to underrate the total installed power and the total admissible current of the converter modules as compared with the total maximum admissible power and current of the dispensers. Furthermore, for high charging currents, using liquid-cooled charging cables significantly improves the cooling effectiveness of the charging system. Moreover, it is suggested that a maximum cooling power of the cooling system shall correspond to that of the maximum of the losses in the dispensers that can be generated with the capacity of the converter modules installed. Thus, according to one aspect of the present disclosure, a charging system is provided, which comprises a multitude of dispensers connected to a multitude of converter modules via a reconfiguration switch and a cooling system, for instance a liquid-cooling system. Different charging-power needs of the dispensers are adjustable due to the connection to the reconfiguration switch which flexibly assigns different numbers of the converter modules to one or several dispensers. It is suggested that a maximum cooling power of the liquid-cooling system is adapted to a maximum of ohmic losses in the dispensers generated with the total installed current capacity of the converter modules. Thus, with regards to its maximum cooling power, the liquid-cooling system is dimensioned in such a way that the liquid-cooling system is capable of preventing the whole charging system from being overheated. Here, a suitable central pump and a suitable P2023,0648 WO E / P230038WO01 July 31, 2023 - 3 - central cooler of the cooling system can be used to adjust the maximum cooling power of the cooling system. According to one embodiment of a charging system for charging electric vehicles, the system comprises a grid interface, a multitude of converter modules connected to the grid interface, a reconfiguration switch, a multitude of dispensers connected to the multitude of converter modules via the reconfiguration switch and a liquid-cooling system. The converter modules are flexibly assigned to the dispensers via the reconfiguration switch for adjusting different charging-power needs of the dispensers. A total installed current capacity of the converter modules is lower than a total installed current capacity of the dispensers. The dispensers are fluidly connected in a cooling loop of the liquid-cooling system. The liquid-cooling system comprises a central cooler and a central pump. A maximum cooling power of the liquid-cooling system, for which the central cooler is dimensioned, is adapted to a maximum of ohmic losses in the dispensers generated with the total installed current capacity of the converter modules. Thus, there is no need to provide different coolers for different dispensers. Using one central cooler, whose maximum cooling power is configured to compensate the maximum of ohmic losses generated in the dispensers, when the dispensers are provided with the total installed current capacity of the converter modules, an over-dimensioning of the cooling system in terms of the cooling power is not required, so that the pump and heat-exchanger capacity can be reduced resulting in a reduction of cost, size and volume of the cooling system and thus of the charging system. P2023,0648 WO E / P230038WO01 July 31, 2023 - 4 - According to a further embodiment of the charging system, the maximum cooling power of the liquid-cooling system is lower than a cooling power corresponding to a maximum of a sum of admissible ohmic losses in the dispensers that would be generated with the total admissible installed current capacity of the dispensers. Since the total installed current capacity of the converter modules is lower than a total installed current capacity of the dispensers, in praxis, the theoretical maximum of the sum of the admissible ohmic losses in the dispensers cannot be attained. Thus, the charging system or the dispensers of the charging system will not be over-heated even if the maximum cooling power of the cooling is lower than a theoretical maximum cooling power that would be needed for compensating the maximum of the sum of the admissible ohmic losses in the dispensers. For example, the maximum cooling power of the liquid-cooling system is from 60 % to 90 %, from 66 % to 90 %, from 66 % to 85 %, from 70 % to 85 % or from 75 % to 85 % of the theoretical maximum cooling power mentioned above that that would be needed for compensating the maximum of the sum of the admissible ohmic losses in the dispensers. According to a further embodiment of the charging system, a total admissible installed power of the converter modules is underrated compared to a total admissible installed power of the dispensers. For instance, a ratio of the total admissible installed power of the converter modules to the total admissible installed power of the dispensers is from 0.5 to 0.95, from 0.5 to 0.9 or from 0.5 to 0.85, from 0.6 to 0.9, from 0.6 to 0.85 or from 0.6 to 0.8. P2023,0648 WO E / P230038WO01 July 31, 2023 - 5 - According to a further embodiment of the charging system, the central pump is designed for a flow rate corresponding to a maximum amount of ohmic losses that are created with a maximum current that the converter modules can provide. Moreover, the central pump is not designed for a flow rate that would be needed if all the dispensers were operating at their maximum charging currents. Thus, the flow rate corresponding to the maximum amount of ohmic losses that are created with the maximum current that the converter modules can provide can form a lower bound when designing the central pump. The flow rate that would be needed if all the dispensers were operating at their maximum charging currents, i.e. at their admissible maximum charging currents, can form a higher bound when designing the central pump. According to a further embodiment of the charging system, the dispensers are fluidly connected in series in the cooling loop of the liquid-cooling system. For instance, each of the dispensers comprises a charging cable which is to be cooled down by the liquid-cooling system. In this case, via fluid conduits forming the cooling loop, the dispensers can be hydraulically in series. Moreover, the dispensers, the central pump and the central cooler can also be hydraulically in series. Here, it is possible that the fluid conduits are in direct or indirect mechanical contact to the charging cables of the dispensers. The fluid conduits can be integrated into the charging cables of the dispensers. The charging cables of the dispensers can be surrounded by the fluid conduits. In this sense, the fluid conduits may form a shell-structure for the charging cables of the dispensers. P2023,0648 WO E / P230038WO01 July 31, 2023 - 6 - According to a further embodiment of the charging system, the liquid-cooling system comprises fluid conduits forming the cooling loop. For instance at least one of the dispensers comprises a flow bypass of one of the fluid conduits. The bypass can be configured to let only one part of a liquid flow passing along the charging cable and another part of the liquid flow bypassing the charging cable. The dispenser comprising a flow bypass can mean that the flow bypass is located at or within the dispenser or that the flow bypass is unambiguously assigned to this dispenser. In this case, the flow bypass can be configured to lead and / or to control an amount or a flow rate of the cooling fluid entering or flowing through the charging cable and / or the connector of this dispenser. The bypass can be considered as part of the dispenser. According to a further embodiment of the charging system, each one of the dispensers comprises one flow bypass. Thus, depending on whether the dispenser is being in operation or not, or whether the dispenser is operating at its maximum charging current or not, a suitable amount or a suitable flow rate of the cooling fluid can be adjusted for this dispenser. Since any of the dispensers can comprise one flow bypass, the cooling system can be operated in a very flexible and efficient manner. According to a further embodiment of the charging system, a flow resistance of the bypasses increases from one dispenser to another dispenser in a downstream direction, resulting in an increasing fraction of the liquid flow through the dispensers located more downstream from the central cooler and / or from the central pump. P2023,0648 WO E / P230038WO01 July 31, 2023 - 7 - Thus, the flow resistance of the bypasses may increase from one dispenser to another dispenser along a downstream direction to form a greater fraction of flow through the charging cable and / or connector of the dispenser located more downstream. This results in a better cooling effect in the cooling system and may at least partially compensate the higher overall temperature level in the more downstream dispensers. According to a further embodiment of the charging system, the flow bypass or each of the flow bypasses comprises an adjustable valve for regulating the liquid flow through the flow bypass. There can be a one-to-one correspondence between the flow bypasses and the valves. The valves can be opened, closed or partially closed to regulate the flow of the cooling fluid through the bypasses. According to a further embodiment of the charging system, the liquid-cooling system is void of any valves or moving parts configured for controlling a liquid flow within the cooling loop. A balancing of temperature rises can be an inherent feature of a series connection of the dispensers. "Balancing" in this context can mean that in a series connection, the temperature rises from an inlet fluid to an outlet fluid add up over all dispensers to the same over all temperature rise from the inlet fluid to the outlet fluid, no matter what the order of the temperature rises is. It is the same way as in a sum, as the order of the summands plays no role, and the sum is always the same. According to a further embodiment of the charging system, the dispensers are fluidly connected in parallel in the cooling P2023,0648 WO E / P230038WO01 July 31, 2023 - 8 - loop of the liquid-cooling system. A flow of a cooling fluid through each dispenser can be controllable through a valve. Here, via the fluid conduits forming the cooling loop, the dispensers can be in hydraulic parallel connection. According to a further embodiment of the charging system, a number of the dispensers is equal to a number of the valves so that there is a one-to-one correspondence between the dispensers and the valves. For adjusting the flow of the cooling fluid to a required cooling power at each dispenser, each of the valves can be adjustable to be fully opened, fully closed, partially opened or partially closed. According to a further embodiment of the charging system, each of the dispensers comprises one associated charging cable and one associated connector. The liquid-cooling system comprises fluid conduits extending along or at least into the one associated charging cable of the dispenser, or extending along or into both the one associated charging cable and the one associated connector of the dispenser. According to a further embodiment of the charging system, the central cooler comprises a main cooler and an additional cooler parallel-connected to the main cooler. Alternatively or in addition, the central pump comprises a main pump and an additional pump parallel-connected to the main pump. According to a further embodiment of the charging system, the liquid-cooling system is configured also for cooling down the converter modules. Here, it is possible for the fluid conduits to extend along or into the converter modules. Very similar to the dispensers, the converter modules can be fluidly connected in series or in parallel. All features P2023,0648 WO E / P230038WO01 July 31, 2023 - 9 - described in the context of hydraulic series or parallel connection of the dispensers can therefore also be used to describe the hydraulic connection of the converter modules. The present disclosure comprises several embodiments of the charging system. Every feature described with respect to one of the embodiments is also disclosed herein with respect to the other embodiments, even if the respective feature is not explicitly mentioned in the context of the specific embodiment. While the disclosure is amenable to various modifications and implementations of the charging system, specifics thereof are shown by way of example in the figures and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments and examples described here. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. The accompanying figures are included to provide a further understanding. In the figures, elements of the same structure and / or functionality may be assigned to the same reference signs. It is to be understood that the examples shown in the figures are illustrative representations and are therefore not necessarily true to scale. Figure 1 shows a general concept of a charging system for charging electric vehicles. Figures 2A, 2B, 3A, 3B, 4A and 4B show some possible realizations of the charging system according to some specific examples. P2023,0648 WO E / P230038WO01 July 31, 2023 - 10 - Figure 1 shows a charging system 10 for charging electric vehicles (EV), for instance for concurrent charging of batteries of multiple electric vehicles. Such a system may be built in a modular way as shown in Figure 1. The charging system 10 comprises a grid interface GI and a multitude of converter modules Cm, here Nmconverter modules Cm 1 to Cm Nm, connected to the grid interface GI. The grid interface comprises a bus (AC or DC) that connects the converter modules, and may further comprise one or several of: step-down transformer, a rectifier transformer with a multi-pulse rectifier, multi-winding transformer, solid-state transformer, AC-to-DC converter, and the like. The system 10 further comprises a reconfiguration switch S and a multitude of dispensers Dn, here Nddispensers Dn 1 to Dn Nd, connected to the multitude of converter modules Cm via the reconfiguration switch S. The number of the converter modules Cm and / or of the dispensers Dn can be larger than 2, 3, 5, 8 or 10. It is possible that the number Nmof the converter modules Cm is equal to, smaller or larger than the number Ndof the dispensers Dn. For having a flexible assignment of the converter modules Cm to the dispensers Dn, the number Nmof the converter modules Cm shall be larger than the number Ndof the dispensers Dn, for instance at least two times or three times larger. The charging system 10 further comprises a liquid-cooling system CS, wherein the liquid-cooling system CS comprises at least a central cooler CC, a central pump CP and fluid conduits Cd. The fluid conduits Cd are configured to lead cooling fluids through the central cooler CC, the central P2023,0648 WO E / P230038WO01 July 31, 2023 - 11 - pump CP and the dispensers Dn. The fluid conduits Cd can form a cooling loop of the cooling system CS. In case that the liquid-cooling system CS is configured also for cooling down the converter modules Cm, it is possible that fluid conduits Cd are configured to lead cooling fluids also through the converter modules Cm. As shown in Figure 1, each of the dispensers Dn comprises one associated charging cable Cb and one associated connector Cn. The fluid conduits Cd can extend along or at least into the one associated charging cable Cb of the dispenser Dn, or along or into both the one associated charging cable Cb and the one associated connector Cn of the dispenser Dn. It is possible for the fluid conduits Cd to extend along or into all charging cables Cb of the dispensers Dn, or along or into all charging cables Cb as well as all connectors Cn of the dispensers Dn. Thus, in operation of the liquid-cooling system CS, the liquid-cooling system CS is configured to cool down the charging cables Cb of dispensers Dn, the connectors Cn of dispensers Dn and / or the converter modules Cm. The dispensers Dn, i.e. the charging cables Cb and optionally the connectors Cn, can be fluidly connected in a cooling loop of the liquid-cooling system CS. It has been observed that it is statistically unlikely that all the dispensers Dn are connected at the same time to an EV or to EVs that request the maximum admissible current of the dispensers. Therefore, this disclosure suggests to reduce the investment cost and to enhance the flexibility as well as the effectiveness of the charging system 10 by underrating a total installed power and a total admissible current of the converter modules Cm as compared to a total maximum P2023,0648 WO E / P230038WO01 July 31, 2023 - 12 - admissible power and a total maximum admissible current of the dispensers Dn, respectively. In this case, a total admissible installed power of the converter modules Cm shall be underrated compared to a total admissible installed power of the dispensers Dn. Moreover, a total installed current capacity of the converter modules Cm shall be lower than a total installed current capacity of the dispensers Dn. The reconfiguration switch S is configured to flexibly assign the converter modules Cm to one dispenser Dn or to several dispensers Dn for adjusting different charging- power needs of the one or several dispensers Dn. The charging system 10 can be configured to provide charging currents for instance of at least 50 A, 100 A, 150 A, 200 A, or to provide high charging currents for instance of at least 250 A, 300 A, 350 A, 400 A, 450 A or 500 A. For example, for charging currents higher than 250 A, 300 A or 350 A, it is highly suitable to use liquid-cooled charging cables Cb and optionally also liquid-cooled connectors Cn. Such high currents above 250 A, 300 A or 350 A are typically used for fast charging of large vehicles such as battery-electric long-haul (BE-LH) trucks. The proliferation of BE-LH trucks is anticipated based on the plans of numerous governments, including those of the European Union and the USA, to reduce carbon emissions in transportation. The charging system 10 described here may provide appropriate fast-charging infra- structure for such BE-LH trucks. So far, in conventional systems for the concurrent charging of multiple EVs, it is rather suggested to over-dimension the cooling system in terms of cooling power. This approach P2023,0648 WO E / P230038WO01 July 31, 2023 - 13 - rather results in high cost, size and volume of the cooling system. For illustrating the suggested solution for reducing the investment cost, size and volume of the cooling system as well as for enhancing the flexibility and effectiveness of the charging system 10 by underrating the total installed power and the total admissible current of the converter modules Cm as compared to the total maximum admissible power and the total maximum admissible current of the dispensers Dn, following quantities are introduced: total number of converter modules (1) maximum admissible current of module ^(usually due to thermal (2) limit) current of module ^ in an operating state total current of the converter modules in an operating state maximum admissible total current of the converter modules (usually (5) due to thermal limit) total number of dispensers, wherein each dispenser can comprise a charging cable and a connector maximum admissible current of ^ dispenser ^, i.e., in cable and ^,^^^,^ connector of dispenser ^ (usually due to thermal limit) losses in dispenser ^ ^̇^,^^^,^(8) corresponding to ^^,^^^,^^ ≤ current of dispenser ^ in an ^,^^^,^^^,^operating state P2023,0648 WO E / P230038WO01 July 31, 2023 - 14 - maximum admissible total current ^^of the dispensers, respecting only the dispenser current limits (10) ^^,^^^,^, but not the converter- module current limit ^^,^^^maximum total dispenser losses (11) corresponding to ^^,^^^maximum total dispenser losses when respecting also the (12) condition ^^≤ ^^,^^^. In praxis, the converter modules Cm and the dispensers Dn have their power and current limits, usually due to temperature limits. Here, the dispenser Dn can be directly associated with its charging cable Cb and connector Cn, wherein the connector Cn is configured to electrically connect the charging system 10 to the EV. Thus, in this disclosure, “dispenser losses” can mean the ohmic losses in the charging cable Cb and in the connector Cn of the associated dispenser Dn. In general, there are different ways of connecting the converter modules Cm to the dispensers Dn that all generate the maximum possible dispenser losses ^̇^,^^^^. This can be illustrated by means of following example: Consider ^^= 3 dispensers, each rated for a maximum current of ^^,^^^,^= 1 kA, yielding ^ = 3 kA. If is the ohmic resistance of dispenser Dn, e.g. of the charging cable Cb and the connector Cn of the dispenser Dn, then ^̇^,^^^^= 3(kA)^^^. Assume further ^^= 10 converter modules Cm of ^^,^^^,^= 200 A each, yielding in total ^^,^^^= 2 kA. Thus, ^^,^^^can be distributed in at least three different ways to always yield the maximum possible P2023,0648 WO E / P230038WO01 July 31, 2023 - 15 - dispenser losses ^̇^,^^^^that respect the current limit of the converter modules, namely: a) no current in dispenser Dn 1; 1 kA each in dispensers Dn 2 and Dn 3; b) no current in dispenser Dn 2; 1 kA each in dispensers Dn 1 and Dn 3; and c) no current in dispenser Dn 3; 1 kA each in dispensers Dn 1 and Dn 2. In each of these cases, ^̇^,^^^^= 2(kA)^^^, which is 33 % lower than ^̇^,^^^^= 3(kA)^^^. Another straightforward way of providing a cooling system for the charging system 10 shown in Figure 1 would be to build into each dispenser Dn its own liquid-to-air cooler that can remove the ohmic losses in the charging cable Cb and the connector Cn of the dispenser Dn by transferring these losses from the cooling liquid to the ambient air. In this case, each cooler can be dimensioned for ^̇^,^^^,^, which results in a total needed cooling power of ^̇^,^^^^= 3(kA)^^^, i.e., 50 % more than necessary from a point of view of the converter modules Cm in the three cases mentioned above having ^̇^,^^^^= 2 (kA)^^^. In contrast to conventional charging systems, this disclosure suggests underrating the total installed power and current capacity of the converter modules Cm as compared to the total installed current capacity of the dispensers Dn. Thus, the total installed current capacity of the converter modules Cm shall be lower than the total installed current capacity of the dispensers Dn. Moreover, a maximum cooling power of the P2023,0648 WO E / P230038WO01 July 31, 2023 - 16 - liquid-cooling system CS, for which the central cooler CC is dimensioned, shall be adapted to a maximum of ohmic losses in the dispensers Dn generated with the total installed current capacity of the converter modules Cm. The adaptation of the central cooler CC to the maximum of ohmic losses in the dispensers Dn means for instance that such a central cooler CC is capable of removing or transferring the maximum of ohmic losses in the dispensers Dn for preventing the system from being overheated. The central cooler CC is configured to transfer the heat of the liquid cooling of the dispensers Dn to the ambient surrounding. This may be the ambient air or any other ambient fluid, such as water, or radiation to the ambient, or a combination of these options. The maximum cooling power of the liquid-cooling system CS, however, can remain lower than a cooling power corresponding to a maximum of a sum of admissible ohmic losses in the dispensers Dn that would be generated with the total admissible installed current capacity of the dispensers Dn. The dispensers Dn can be fluidly connected in a cooling loop of the liquid-cooling system CS, wherein the liquid-cooling system CS comprises the central cooler CC and a central pump CP. The liquid-cooling system CS further comprises fluid conduits Cd. Via the fluid conduits Cd, the cooling liquid can be transferred from the central cooler CC to the dispensers Dn and back by using the central pump CP. The dispensers Dn can be fluidly connected in series or in parallel in the cooling loop of the liquid-cooling system CS. Figures 2A and 2B show the charging system 10, wherein the dispensers Dn are fluidly connected in series in the cooling P2023,0648 WO E / P230038WO01 July 31, 2023 - 17 - loop of the liquid-cooling system CS. Figures 3A and 3B show the charging system 10, wherein the dispensers Dn are fluidly connected basically in series, wherein flow bypasses Bp are integrated in the cooling loop of the liquid-cooling system CS. Figures 4A and 4B show the charging system 10, wherein the dispensers Dn are fluidly connected in parallel in the cooling loop of the liquid-cooling system CS. Here, the route of the fluid conduits Cd as well as possible interconnections of the fluid conduits Cd determine whether the dispensers Dn are fluidly connected in series or in parallel. In Figures 2A to 4B, the grid interface GI is electrically connected to a grid G. As shown in Figure 2A, the individual dispensers Dn are fluidly connected in series. Hence, the fluid conduits Cd form a loop extending through the central cooler CC, the central pump CP and the dispensers Dn. The rise in temperature of the liquid from an inlet to an outlet of an individual dispenser Dn i with ^ = is where ^̇ and ^^are the mass-flow rate of the cooling liquid and its specific heat at constant pressure, respectively. The total temperature rise ∆^^of the cooling liquid, i.e. the temperature rise over all the dispensers Dn, determines the temperature level of the last and most critical dispenser Dn in the series connection and is therefore decisive for the performance of the cooling system. Depending on the flow direction of the cooling fluid, the last and most critical P2023,0648 WO E / P230038WO01 July 31, 2023 - 18 - dispenser Dn in Figure 2A is the dispenser Dn 1 or Dn ^^. The total temperature rise ∆^^is determined as follows: Using equation (12), the maximum of ∆^^is: Hence, the cooling system CS can be designed based on the lower losses ^̇^,^^^^, rather than based on the higher losses ^̇^,^^^^. In other words, with regard to its capability, the cooling system CS can be adapted to the lower losses ^̇^,^^^^but not to the higher losses ^̇^,^^^^. For instance, the central cooler CC and / or the central pump CP of the cooling system CS are configured to deal with the lower losses ^̇^,^^^^but not to deal with the higher losses ^̇^,^^^^. The lower losses ^̇^,^^^^can form a lower bound while the higher losses ^̇^,^^^^can form a higher bound when designing the central cooler CC and / or the central pump CP. Notably, in the examples mentioned above, ^̇^,^^^^is the same for the cases a), b) and c). In other words, no matter how the losses are distributed over the dispensers Dn, the total temperature rise caused by the dispensers Dn is always the same. Hence, the maximum temperature that can occur in an operating state in the last most downstream dispenser Dn in the series connection is always the same. It is worth mentioning that this feature or technical effect is achieved P2023,0648 WO E / P230038WO01 July 31, 2023 - 19 - without any valves or other elements controlling the flow of the cooling fluids. The balancing of the temperature rises, i.e., their adding up to the same total temperature rise, is an inherent feature of the series connection and does not require any moving parts or an active control of the flow of the cooling fluids. This holds true not only for the explicit cases a), b) and c) mentioned above but also for more general cases shown for instance in Figure 2A. Thus, as schematically shown in Figure 2A, the liquid-cooling system CS can be void of any valves or moving parts configured for controlling a liquid flow within the cooling loop. The balancing of temperature rises is rather an inherent feature of a series connection of the dispensers Dn. In other words, the cooling system CS comprises a cooling fluid loop being a purely passive fluid circuit. In Figure 2A, the fluid conduits Cd extend through or along the central cooler CC as well as the central pump CP and run along or into the charging cables Cb of the dispensers Dn. It is possible for the fluid conduits Cd to extend also along or into the connectors Cn. The fluid conduits Cd is configured to conduct the cooling fluids and can be in direct or indirect contact with the charging cables Cb and / or the connectors of the dispensers Dn. Figure 2A shows schematically that the central cooler CC comprises a main cooler mC. The main cooler mC can be the only cooler of the central cooler CC and is adapted to the maximum of ohmic losses in the dispensers Dn generated with the total installed current capacity of the converter modules Cm. Figure 2A further shows that the central pump CP comprises a main pump mP which can be the only pump of the P2023,0648 WO E / P230038WO01 July 31, 2023 - 20 - central pump CP and is designed to deal with the maximum of ohmic losses in the dispensers Dn. Compared to the example shown in Figure 2A, according to Figure 2B, the central cooler CC comprises a main cooler mC and an additional cooler aC parallel-connected to the main cooler mC. For instance, the main cooler mC and the additional cooler aC are capable of being operated independently from each other. On one hand, this enhances the flexibility in adjusting the cooling power of the liquid- cooling system CS. On the other hand, the central cooler CC comprises two parallel-connected coolers for redundancy. Compared to the example shown in Figure 2A, according to Figure 2B, the central pump CP comprises a main pump mP and an additional pump aP parallel-connected to the main pump mP. For instance, the main pump mP and the additional pump aP are capable of being operated independently from each other. This enhances the flexibility in adjusting the cooling power of the liquid-cooling system CS. Furthermore, the central pump CP comprises two parallel-connected pumps for redundancy. For example, the central pump CP comprising only the main pump mP or both the main pump mP and the additional pump is designed for a flow rate corresponding to a maximum amount of ohmic losses that are created with a maximum current that the converter modules Cm can provide. It is possible, however, that the central pump CP is not designed for a flow rate that would be needed if all the dispensers Dn were operating at their maximum charging currents. In deviation from Figures 2A and 2B, it is also possible for the liquid-cooling system CS to be configured for cooling P2023,0648 WO E / P230038WO01 July 31, 2023 - 21 - down not only the dispensers Dn but also the converter modules Cm. The example of the charging system 10 shown in Figure 3A is substantially the same as the example of the charging system 10 shown in Figure 2A. In contrast, flow bypasses Bp are provided in the dispensers Dn or in the cooling system CS at the dispensers Dn. Without the bypass Bp, the entire cooling liquid would flow through the charging cable Cb and optionally through the connector Cn of the dispenser Dn or of each dispenser Dn. However, in some cases, this may not be desirable, for instance when the dispenser Dn in question is not connected to an electric vehicle and therefore does not need to be cooled down. In such cases, if there are no bypasses Bp in the cooling system CS, the cooling system may have the disadvantage of either causing a large pressure drop or requiring a large cross-section of the fluid conduits Cd in the charging cables Cb resulting in unnecessarily thick charging cables Cb. At one end of the bypass Bp, the fluid conduit Cd from the charging cable Cb and the bypass-conduit join and the two streams of liquid are mixed to yield an average temperature according to the mass-flow rates. As shown in Figure 3A, the cooling system CS can comprise one bypass Bp in or at each of the dispensers Dn. In this sense, each one of the dispensers Dn can comprise one flow bypass Bp. Thus, each dispenser Dn can comprise one flow bypass Bp of one of the fluid conduits Cd that leads along the charging cable Cb of the corresponding dispenser Dn, such that only one part of a liquid flow passes along the charging cable Cb and another part of the liquid flow bypasses the charging cable Cb. P2023,0648 WO E / P230038WO01 July 31, 2023 - 22 - The bypasses Bp of the charging system 10 can be formed for instance with regard to their sizes and geometries in such a way that a flow resistance of the bypasses Bp increases from one dispenser Dn to another dispenser Dn in a downstream direction. This arrangement causes an increasing fraction of the liquid flow through the dispensers Dn located more downstream from the central cooler CC and / or from the central pump CP resulting in an increased overall efficiency of the cooling system. In other words, the flow resistance of the bypasses Bp increases from one dispenser Dn to another dispenser Dn in downstream direction to force a greater fraction of flow through the charging cable Cb in the more downstream dispenser Dn. This leads to a better cooling effect in the charging cables Cb and may at least partially compensate the higher overall temperature level in the more downstream dispensers Dn. For adjusting the flow resistance of the bypasses Bp, it is possible for the bypasses Bp to have adjustable valves V. The valves V can be used for regulating the liquid flow through the flow bypasses Bp. For instance, some or each of the flow bypasses Bp comprises an adjustable valve V. This is schematically shown in Figure 3B. For adjusting the flow of the cooling fluid to a required cooling power at each dispenser Dn, each of the valves V is adjustable to be fully opened, fully closed, partially opened or partially closed. It is possible that a number of the dispensers Dn is equal to a number of the valves V so that there is a one-to-one correspondence between the dispensers Dn and the valves V. In deviation from Figure 3A, according to Figure 3B and very similarly to Figure 2B, the central cooler CC can comprise a main cooler mC and an additional cooler aC parallel connected P2023,0648 WO E / P230038WO01 July 31, 2023 - 23 - to the main cooler mC. Hence, the two coolers or heat exchangers are parallel connected for redundancy. One cooler may be replaced while the other one keeps running. Moreover, the central pump CP can comprise a main pump mP and an additional pump aP parallel-connected to the main pump mP. Thus, the two pumps can be parallel connected for redundancy. One pump may be replaced while the other one keeps running. It is also possible to integrate valves V at the main pump mP and / or at the additional pump aP. These valves V can be individually adjusted to be fully opened, fully closed, partially opened or partially closed. Figures 4A and 4B show the charging system 10 schematically shown in Figure 1 for the case that the dispensers Dn are fluidly connected in parallel in the cooling loop of the liquid-cooling system CS. Hence, the individual dispensers Dn are fluidly connected in parallel, wherein the valves V are configured to control the flow rate of the cooling fluid to each dispenser Dn. Thus, a flow or a flow rate of the cooling fluid through each dispenser Dn is controllable through a corresponding valve V. In case a dispenser Dn is not operating and thus is not generating ohmic losses, no flow rate is required, and unnecessary pumping of cooling fluid through the charging cable Cb and / or the connector Cn of the respective dispenser Dn can be avoided. In case that one dispenser Dn is not operating at full power but rather at reduced power and thus generates reduced losses, only low flow rate at this dispenser Dn is required. Thus, the flow rate can be reduced to the needed amount by partially closing the respective valve V. P2023,0648 WO E / P230038WO01 July 31, 2023 - 24 - Hence, according to the charging system 10 shown in Figure 4A or 4B, it can be regulated that only a required amount of cooling fluid is pumped through the charging cable Cb and / or the connector Cn the dispenser Dn. In particular, the central pump CP needs to be designed only for a flow rate that corresponds to the maximum amount of ohmic losses that can be generated with the maximum current that the converter modules Cm can be provided. In particular, it can be avoided that the central pump Cp is designed for the flow rate that would be needed if all the dispensers Dn were operating at their maximum charging currents and / or charging powers. In deviation from Figure 4A, according to Figure 4B and very similarly to Figures 2B and 3B, the central cooler CC can comprise a main cooler mC and an additional cooler aC parallel-connected to the main cooler mC. Moreover, the central pump CP can comprise a main pump mP and an additional pump aP parallel-connected to the main pump mP. As shown in Figure 4A and 4B, the number of the dispensers Dn can be equal to a number of the valves V so that there is a one-to-one correspondence between the dispensers Dn and the valves V. For adjusting the flow of the cooling fluid to a required cooling power at each dispenser Dn, each of the valves V can be adjusted for instance independently from the other. The valves V can be fully opened, fully closed, partially opened or partially closed to meet the actual need of the amount or flow rate of the cooling fluid at each dispenser Dn. In this disclosure, different examples of a charging system for the charging of a multitude of electric vehicles are provided. The system can comprise a multitude of dispensers P2023,0648 WO E / P230038WO01 July 31, 2023 - 25 - with charging cables and connectors, a multitude of converter modules connected to a grid via a grid interface, a reconfiguration switch, and a liquid-cooling system for cooling down the dispensers and / or the converter modules. The liquid-cooling system can comprise a central cooler and a central pump. The converter modules are flexibly connectable to the dispensers via the reconfiguration switch to satisfy different charging-power needs of the dispensers. In a cooling loop of the liquid-cooling system, the dispensers can be fluidly connected in series or in parallel. A maximum cooling power, for which the central cooler and / or the central pump are / is dimensioned, corresponds to that of the maximum of the losses in the dispensers that can be generated with the capacity of the converter modules installed. In case the dispensers are fluidly connected in parallel in the cooling loop, a flow of a cooling fluid through each dispenser can be controlled by valves, which are configured to adjust a flow rate of the cooling fluid to the needed cooling power. In case the dispensers are fluidly connected in series in the cooling loop, the temperature rises of the cooling liquid of the dispensers can add up to about the same value, no matter how the losses are distributed among the dispensers as long as the sum of the losses remains the same, wherein due to the series connection, the central cooler can be dimensioned for a maximum cooling power lower than that corresponding to the sum of the maximum admissible losses of each individual dispenser. The embodiments shown in the Figures as stated represent only some examples of the charging system; thus they do not constitute a complete list of all examples according to the improved arrangement for the charging system. Actual P2023,0648 WO E / P230038WO01 July 31, 2023 - 26 - arrangements of the charging system may vary from the examples described above. Moreover, the present disclosure comprises several embodiments and examples of the charging system. Every feature described with respect to one of the embodiments or examples is also disclosed herein with respect to other embodiments or example even if the respective feature is not explicitly mentioned in the context of the specific embodiment or example.

[0002] P2023,0648 WO E / P230038WO01 July 31, 2023 - 27 - List of references signs 10 charging system G grid GI grid interface Cm converter module S reconfiguration switch Dn dispenser Cb charging cable of the dispenser Cn connector of the dispenser CS liquid-cooling system CC central cooler mC main cooler aC additional cooler CP central pump mP main pump aP additional pump Cd fluid conduits Bp bypass V valve

Claims

P2023,0648 WO E / P230038WO01 July 31, 2023 - 28 - Claims 1. A charging system (10) for charging electric vehicles, the system (10) comprising a grid interface (GI), a multitude of converter modules (Cm) connected to the grid interface (GI), a reconfiguration switch (S), a multitude of dispensers (Dn) connected to the multitude of converter modules (Cm) via the reconfiguration switch (S), and a liquid-cooling system (CS), wherein ^ the converter modules (Cm) are flexibly assigned to the dispensers (Dn) via the reconfiguration switch (S) for adjusting different charging-power needs of the dispensers (Dn), ^ a total installed current capacity of the converter modules (Cm) is lower than a total installed current capacity of the dispensers (Dn), ^ the dispensers (Dn) are fluidly connected in a cooling loop of the liquid-cooling system (CS), ^ the liquid-cooling system (CS) comprises a central cooler (CC) and a central pump (CP), and ^ a maximum cooling power of the liquid-cooling system (CS), for which the central cooler (CC) is dimensioned, is adapted to a maximum of ohmic losses in the dispensers (Dn) generated with the total installed current capacity of the converter modules (Cm).

2. The charging system (10) according to claim 1, wherein the maximum cooling power of the liquid-cooling system (CS) is lower than a cooling power corresponding to a maximum of a sum of admissible ohmic losses in the dispensers (Dn) that would be generated with the total admissible installed current capacity of the dispensers (Dn).P2023,0648 WO E / P230038WO01 July 31, 2023 - 29 - 3. The charging system (10) according to any of claims 1 to 2, wherein a total admissible installed power of the converter modules (Cm) is underrated compared to a total admissible installed power of the dispensers (Dn).

4. The charging system (10) according to any of claims 1 to 3, wherein the central pump (CP) is designed ^ for a flow rate corresponding to a maximum amount of ohmic losses that are created with a maximum current that the converter modules (Cm) can provide, and ^ not for a flow rate that would be needed if all the dispensers (Dn) were operating at their maximum charging currents.

5. The charging system (10) according to any of claims 1 to 4, wherein the dispensers (Dn) are fluidly connected in series in the cooling loop of the liquid-cooling system (CS), and wherein each of the dispensers (Dn) comprises a charging cable (Cb) which is to be cooled down by the liquid-cooling system (CS).

6. The charging system (10) according to claim 5, wherein ^ the liquid-cooling system (CS) comprises fluid conduits (Cd) forming the cooling loop, and ^ at least one of the dispensers (Dn) comprises a flow bypass (Bp) of one of the fluid conduits (Cd) that leads along the charging cable (Cb) of the at least one dispenser (Dn), such that only one part of a liquid flow passes along the charging cable (Cb) and another part of the liquid flow bypasses the charging cable (Cb).P2023,0648 WO E / P230038WO01 July 31, 2023 - 30 - 7. The charging system (10) according to any of claims 5 to 6, wherein each one of the dispensers (Dn) comprises one flow bypass (Bp).

8. The charging system (10) according to any of claims 6 to 7, wherein a flow resistance of the bypasses (Bp) increases from one dispenser (Dn) to another dispenser (Dn) in a downstream direction, resulting in an increasing fraction of the liquid flow through the dispensers (Dn) located more downstream from the central cooler (CC) and / or from the central pump (CP).

9. The charging system (10) according to any of claims 6 to 8, wherein the flow bypass (Bp) or each of the flow bypasses (Bp) comprises an adjustable valve (V) for regulating the liquid flow through the flow bypass (Bp).

10. The charging system (10) according to any of claims 5 to 8, wherein the liquid-cooling system (CS) is void of any valves or moving parts configured for controlling a liquid flow within the cooling loop, and wherein a balancing of temperature rises is an inherent feature of a series connection of the dispensers (Dn).

11. The charging system (10) according to any of claims 1 to 4, wherein ^ the dispensers (Dn) are fluidly connected in parallel in the cooling loop of the liquid-cooling system (CS), and ^ a flow of a cooling fluid through each dispenser (Dn) is controllable through a valve (V).

12. The charging system (10) according to claim 11,P2023,0648 WO E / P230038WO01 July 31, 2023 - 31 - wherein a number of the dispensers (Dn) is equal to a number of the valves (V) so that there is a one-to-one correspondence between the dispensers (Dn) and the valves (V), and wherein, for adjusting the flow of the cooling fluid to a required cooling power at each dispenser (Dn), each of the valves (V) is adjustable to be fully opened, fully closed, partially opened or partially closed.

13. The charging system (10) according to any of claims 1 to 12, wherein ^ each of the dispensers (Dn) comprises one associated charging cable (Cb) and one associated connector (Cn), and ^ the liquid-cooling system (CS) comprises fluid conduits (Cd) extending along or into the one associated charging cable (Cb) of the dispenser (Dn), or along or into both the one associated charging cable (Cb) and the one associated connector (Cn) of the dispenser (Dn).

14. The charging system (10) according to any of claims 1 to 13, wherein ^ the central cooler (CC) comprises a main cooler (mC) and an additional cooler (aC) parallel-connected to the main cooler (mC), and / or ^ the central pump (CP) comprises a main pump (mP) and an additional pump (aP) parallel-connected to the main pump (mP).

15. The charging system (10) according to any of claims 1 to 14, wherein the liquid-cooling system (CS) is configured also for cooling down the converter modules (Cm).

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