Method and apparatus for operating a fleet of charging stations having a plurality of charging stations for charging batteries of devices

Abstract

The present invention relates to a method for operating a group of charging stations (1) having multiple charging stations (2) for charging device batteries (41) of technical equipment (4), the method comprising the steps of: - providing (S2) a corresponding charging start time, a corresponding charging end time, a corresponding final charging state and a corresponding initial charging state for the multiple device batteries (41); - providing the maximum total charging power that can be provided by the charging stations of the group of charging stations (1); - performing (S3) an optimization method to obtain charging characteristics for each device battery (41) such that each device battery (41) reaches its respective final charging state at the latest at the respective provided charging end time without exceeding the maximum total charging power of the group of charging stations; - performing (S4) a charging process of the device batteries (41) according to the pre-given charging characteristics.

Description

Technical Field

[0001] This invention relates to a group of charging stations having multiple charging stations for charging device batteries, and more particularly to a control method for controlling the charging process of multiple device batteries at the charging stations. Background Technology

[0002] A common need when operating a fleet of electric vehicles, especially commercial vehicles, is to fully charge the batteries of all commercial vehicles as much as possible before the start of each day.

[0003] This allows for no recharging or only a small recharge during short driving breaks during the day, thus providing enough energy to complete daily driving tasks.

[0004] To charge the batteries of such vehicles as quickly as possible, a charging method is typically employed that involves rapidly charging the battery in a first charging phase using a pre-defined, relatively high charging current until, for example, reaching a maximum state of charge (SOC) of 80%. A charging interval is then incorporated, during which the battery temperature is reduced through cooling. Following the charging interval, the battery is fully charged in a second charging phase using a constant voltage method and a low charging current.

[0005] A cluster of charging stations typically consists of multiple charging stations that are supplied with electricity by a common power supplier.

[0006] Because multiple vehicle batteries are typically charged simultaneously, the high charging current during the first charging phase can accumulate into a total charging power that cannot be provided by a power supplier with a network of charging stations.

[0007] Furthermore, rapid charging of vehicle batteries can lead to severe degradation. This can be avoided if the chosen charging characteristics are designed to accommodate a lower charging current during the charging process. This conflicts with the requirement to charge the vehicle battery until a predetermined end time of charging and until a predetermined final state of charge (typically full charge).

[0008] The aforementioned issues are not limited to vehicle batteries, but also involve batteries for other high-power devices that must be charged regularly in time-critical applications. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a method for operating a group of charging stations having multiple charging stations for charging device batteries, wherein, taking into account the maximum total charging power and, if necessary, minimizing battery degradation, the required charging of all device batteries up to a separately predetermined charging end time can be achieved.

[0010] This objective is achieved by the method of claim 1 for operating a group of charging stations having multiple charging stations for charging the batteries of technical equipment, and by the equipment and group of charging stations according to the parallel claims.

[0011] Other design options are described in the dependent claims.

[0012] According to the first aspect, a method for operating a group of charging stations having multiple charging stations for charging device batteries is provided, the method comprising the following steps: - Provides corresponding charging start time, corresponding charging end time, corresponding final charging state, and corresponding initial charging state for multiple device batteries. The charging start time is the earliest time the device battery can begin charging, and the charging end time is the latest time the device battery should be charged. The final charging state corresponds to the charging state required at the charging end time, and the initial charging state indicates the charging state at the charging start time. - Provides the maximum total charging power that can be provided by all charging stations in the charging station cluster. - Implement optimization methods to determine the charging characteristics for each device battery in the device battery cluster, ensuring that each device battery reaches its final state of charge no later than the end of its respective charging period, without exceeding the maximum total charging power of the charging station cluster. - Perform the charging process of the device battery according to the pre-given charging characteristics.

[0013] Specifically, the charging characteristics can be determined by multiple charging process parameters, which include one or more of the following parameters: - The charging current during the first charging phase, or multiple charging currents depending on the state of charge range, during which the device battery is charged with one or more associated charging currents. - The moment when the ultimate charging state is reached corresponds to the end of the first charging phase. - The duration of the charging interval during which no charging occurs and the battery temperature is allowed to decrease. - A constant charging current and a subsequent constant voltage are used for charging during the second charging phase, in which the device battery is charged with a constant current and then with a constant voltage in order to reach the final state of charge.

[0014] To operate a cluster of charging stations, the method described above pre-defines corresponding charging characteristics for multiple device batteries. These charging characteristics must, on the one hand, meet required characteristics (according to which the device batteries should be charged until a specific time) and on the other hand, not exceed a pre-defineed maximum value for the total charging power.

[0015] This approach uses a cost function to evaluate whether all device batteries have reached their desired final state of charge by the end of the optimization time period. Optimization is performed under the condition that the maximum total charging power is not allowed to be exceeded at any point during the considered optimization time period.

[0016] The method can be executed using an optimized time domain, which specifically corresponds to the latest charging end time or a slightly later time at which all vehicle batteries should reach the desired final state of charge.

[0017] Taking into account the availability requirements of device batteries and the power limitations imposed by the maximum total charging power of the charging station cluster, the above method enables charging management for multiple device batteries.

[0018] The method optimizes all charging characteristics of a device battery to be charged, which are configured to be charged using a CCCV charging scheme. The CCCV charging scheme is configured to first charge with a pre-given charging current (particularly depending on the range of the state of charge) in a first charging phase, followed by charging intervals, and a second charging phase with constant voltage.

[0019] This enables a final state of charge up to 100% SOC, even for the CCCV charging method, so that it is readily available at the end of the charging process.

[0020] In another implementation, the cost function can further account for the degradation of the device battery caused by charging with relevant charging characteristics. Here, the optimization method should aim to minimize the overall degradation of all device batteries awaiting charging, up to the optimization time domain.

[0021] In particular, degradation can be determined by means of an aging state model, which evaluates the temporal current and temperature trends during the CCCV charging process in order to optimize the changes in the aging state of the device battery in the time domain.

[0022] Aging states can be simulated or determined using conventional and known aging state models. In particular, electrochemical aging state models, which are in principle based on electrochemical cell models, can be used. Such electrochemical cell models can include a system of differential equations that, based on differential equations parameterized by model parameters, model the internal cell state, especially the equilibrium state and, where necessary, the kinetic state, using time integration. This provides the relationship between the temporal trends of the device cell's operating parameters (i.e., cell current, cell voltage, cell temperature, and the state of charge of the device cell) and the internal cell state. Such electrochemical cell models are known, for example, from US20230305073A1, US20220179009A1, US20220334191A1, US20220099743A1, US2016 / 023,566, US2016 / 023,567, and US2020 / 150,185. The aging state can be derived from the internal battery state. Data-based models or hybrid models can also be used as aging state models to determine changes in aging state.

[0023] If trends in battery current and temperature exist, the temporal trend of battery voltage can be determined using a battery model, for example, in the form of an equivalent circuit diagram model, and the temporal trend of the state of charge can be determined through charge accumulation. Thus, the degradation of the relevant device battery during the CCCV process can be determined through an aging state model. The temporal trend of temperature can be determined using a temperature equilibrium model that relies on the charging current taking into account thermal input and models the temporal development of battery temperature through thermal equilibrium observation.

[0024] In this way, the degradation (aging state change) at a given moment in the optimization time domain can be determined by using an aging state model.

[0025] Furthermore, the optimization method can be re-executed when a new device battery is connected to one of the charging stations or when one of the device batteries is disconnected from one of the charging stations. Attached Figure Description

[0026] The implementation method will now be explained in more detail with reference to the accompanying drawings. Wherein: Figure 1 A schematic diagram of a cluster of charging stations with multiple charging stations is shown, which are set up to charge the vehicle batteries of electric vehicles. Figure 2 A flowchart illustrating a method for charging management in a charging station cluster is shown. Figure 3 A feasible scheme for modifying charging characteristics through optimization methods is shown. Detailed Implementation

[0027] Figure 1 A group of charging stations 1 with multiple charging stations 2 is schematically shown, designed to charge the vehicle battery 41 of an electric vehicle 4. The electric vehicle 4 can be, for example, a commercial vehicle or a similar vehicle. Other battery types requiring high charging power for various other technological devices can also be charged using the methods described below.

[0028] The objective is to fully charge the vehicle battery 41 within a relatively short period of time, up to a pre-defined end time for charging. In particular, there is a need in commercial vehicles to achieve full charging of multiple vehicle batteries 41 overnight.

[0029] The method is typically implemented using an optimized time domain that ends at a predetermined time the following morning or at a pre-defined charging end time, so that the electric vehicle 4 is ready to start. Needless to say, other optimized time domains can also be pre-defined, wherein the optimized time domain can correspond, in particular, to the latest charging end time at which all vehicle batteries 41 should reach the desired final state of charge.

[0030] The charging station cluster has a charging management system 3, which controls the energy flow to the charging station 2 and pre-determines the corresponding charging characteristics for the connected vehicle battery 41.

[0031] The charging management system 3 includes a data processing unit 31 to execute an optimization method to determine the charging characteristics for the vehicle battery 41. The charging characteristics are defined by the charging current or charging voltage within the time trend of the optimization time domain.

[0032] The charging characteristics are based on a CCCV charging scheme, which exemplarily demonstrates... Figure 3 As shown in the figure, the CCCV charging scheme includes: a first charging phase having a time characteristic of one or more pre-defined charging currents; a charging interval following the first charging phase during which no charging current flows; and a subsequent second charging phase having a constant voltage in which the vehicle battery 41 is charged at the constant voltage until it reaches a final state of charge.

[0033] Specifically, the charging characteristics can be determined by multiple charging process parameters, which include one or more of the following parameters: - The charging current IL during the first charging phase, or multiple charging currents depending on the state of charge range, during which the vehicle battery 41 is charged with one or more associated charging currents. - The moment tG when the predetermined limit charging state is reached corresponds to the end of the first charging phase (the starting charging state and the charging current of the first charging phase can be determined by the limit charging state). - The duration tD of the charging interval, during which no charging occurs and the battery temperature is allowed to decrease. - A constant voltage UK is used for charging during the second charging phase, in which the vehicle battery 41 is charged at a constant voltage in order to reach the final state of charge.

[0034] Here, the charging characteristics are obtained from the initial charging state, which corresponds to the charging state that the vehicle battery 41 has at the start of charging when it is connected to the charging station.

[0035] Here, the moment when the first charging phase reaches a predetermined limit state of charge (e.g., 80% SoC) can be determined by accumulating the charge introduced into the vehicle battery 41 by the charging current set for the first charging phase. This moment corresponds to the end of the first charging phase. Therefore, the duration of the first charging phase is obtained by the charging current set for the first charging phase.

[0036] Alternatively, the first charging phase can be defined by multiple sub-segments with different charging currents, wherein the limiting charging state of the first charging phase is determined by the time integral of the charging current of the sub-segments.

[0037] The charging intervals can vary in duration and allow for cooling of the vehicle battery to achieve the lowest possible temperature for the constant current constant voltage charging process (CCCV) during the second charging phase, thereby reducing the stress load on the vehicle battery 41 during the second charging phase.

[0038] The charging current time trend is obtained from the entire charging characteristics, and the battery temperature time trend can be derived from the charging current time trend by means of an appropriate temperature model.

[0039] Temperature characteristics indicate the trend of battery temperature with respect to time, especially with respect to the duration of the optimization time domain, and can be obtained using a thermal equilibrium model.

[0040] The degradation of vehicle batteries can be determined from the trends of temperature and charging current using known electrochemical aging state models.

[0041] An optimization method can be executed in the data processing device 31. This optimization method calculates the corresponding charging characteristics for multiple vehicle batteries 41 that need to be charged, thereby achieving the desired final charging state of the vehicle batteries 41 at the end of the optimization time domain. To this end, the optimization method uses the corresponding charging characteristic parameter set to simulate the charging characteristics and minimizes the corresponding cost according to the cost function.

[0042] Typically, the final state of charge is defined as the state of charge of a fully charged vehicle battery (SOC=100%).

[0043] An optimization method can be performed based on a cost function that evaluates whether all vehicle batteries 41 are charged to their respective final state of charge until their respective end-of-charge time, and optionally considers the overall degradation of all vehicle batteries in a cost-increasing manner using the obtained charging characteristics. The overall degradation of all vehicle batteries 41 can be determined by the sum of the aging state changes of the charging characteristics simulated during the optimization method.

[0044] The optimization auxiliary condition is that the maximum total charging power that the charging station group can provide will never be exceeded at any time.

[0045] Once a certain number of vehicle batteries 41 are connected to the charging station, the optimization method is activated.

[0046] If another vehicle battery 41 is connected to a charging station in the charging station group, the optimization method will always be reimplemented.

[0047] exist Figure 2 The diagram shows a flowchart illustrating a method for running charging management of charging station group 1.

[0048] In step S1, it is first checked whether a predetermined number of vehicle batteries are connected to the charging station.

[0049] If this is the case (either option: yes), then continue with step S2; otherwise (either option: no), then jump back to step S1.

[0050] In step S2, for all vehicle batteries 41 awaiting charging, the corresponding instantaneous charging state is considered as the corresponding initial charging state of the vehicle battery 41. Furthermore, the required final charging state and the desired charging end time are obtained from a database or other source.

[0051] In step S3, an optimization method is now performed, wherein charging characteristic parameters for the charging characteristics associated with the vehicle battery 41 are determined.

[0052] In step S4, the charging process is initiated according to the pre-given charging characteristics.

[0053] In step S5, it is checked whether another vehicle battery 41 is connected to one of the charging stations 2 or whether one of the connected vehicle batteries 41 is disconnected from one of the charging stations 2. If this is the case (either option: yes), the method continues to step S6; otherwise (either option: no), it jumps back to step S5.

[0054] In step S6, the starting charging state, the desired final charging state, and the required charging end time are queried for the other connected vehicle battery 41, and the optimization method is restarted by jumping back to step S3.

Claims

1. A method for operating a group (1) of charging stations (2) for charging a device battery (41) of a technical device (4), the method comprising the steps of: - Provide (S2) corresponding charging start time, corresponding charging end time, corresponding final charging state, and corresponding starting charging state for multiple device batteries (41), wherein, The charging process of the device battery (41) can be started at the earliest at the charging start time, and the device battery (41) should be charged at the latest at the charging end time. This final charging state corresponds to the charging state required at the charging end time, and the initial charging state indicates the charging state at the charging start time. - Provides the maximum total charging power that can be provided by all the charging stations in the charging station group (1). - Execute the (S3) optimization method to obtain the charging characteristics for each device battery in the device battery (41) so that each device battery in the device battery (41) reaches its respective final charging state at the latest at the end of its respective charging time, without exceeding the maximum total charging power of the charging station group. - Perform the charging process of the device battery (41) according to the pre-given charging characteristics (S4).

2. The method according to claim 1, Its features are, The charging feature has a CCCV charging scheme, which in particular has: - The first charging phase, during which charging is performed with a constant charging current or a charging current that depends on the state of charging. - Subsequent charging intervals, during which no charging current is supplied, are used to reduce battery temperature. - The subsequent second charging phase, during which charging is performed with a constant current and then with a constant voltage.

3. The method according to claim 2, Its features are, The charging characteristics are determined by a plurality of charging characteristic parameters, which include one or more of the following parameters: - The charging current during the first charging phase, or multiple charging currents depending on the state of charge range, during which the device battery is charged with one or more associated charging currents. - The moment when the ultimate charging state is reached corresponds to the end of the first charging phase. - The duration of the charging interval during which no charging occurs and the battery temperature is reduced. - A constant charging current and a subsequent constant voltage are used for the charging during the second charging phase, in which the device battery (41) is charged with the constant voltage after being charged with the constant current in order to reach the final charging state.

4. The method according to any one of the preceding claims, Its features are, The optimization method is based on a cost function. The optimization method is configured to optimize charging characteristic parameters for a device battery (41) to be charged, taking into account charging characteristics. The cost function is defined such that a reward is given for reaching the final charging state at or before the corresponding end of charging.

5. The method according to claim 4, Its features are, The cost function is additionally configured to minimize the overall degradation of the device battery during the charging process, which utilizes the corresponding charging characteristics considered during the optimization method.

6. The method according to any one of the preceding claims, in, The optimization method is re-executed when a new device battery (41) is connected to one of the charging stations (2) or when one of the device batteries (41) is disconnected from one of the charging stations (2).

7. The method according to any one of the preceding claims, in, The optimization method is performed for an optimization time domain that corresponds to the latest charging end time or a slightly later time when all connected vehicle batteries (41) should reach the desired final charging state.

8. A charging management system for operating a group (1) of charging stations having multiple charging stations (2), the charging management system comprising a data processing device (31) designed to perform the method according to any one of claims 1 to 7.

9. An apparatus for performing the method according to any one of claims 1 to 7.

10. A computer program product comprising instructions that, when the program is executed by at least one data processing device (31), cause the data processing device to perform the steps of the method according to any one of claims 1 to 7.

11. A machine-readable storage medium comprising instructions, when implemented by at least one data processing device, causing the data processing device to perform the steps of the method according to any one of claims 1 to 7.

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