Method / device for operating PCS in the most efficient section

Abstract

An embodiment of the present invention provides a power control system and method including: an energy storage system (ESS) connected to a power grid and having a battery; a power conversion system (PCS) operatively connected to the power grid and the energy storage system (ESS); and a control unit that provides control to execute charging and discharging procedures for the battery with priority given to power conversion efficiency of the power conversion system (PCS).

Description

[Technical Field]

[0001] The present invention relates to an integrated system that combines an energy storage device (ESS) and a charger, and more particularly, to a method / apparatus for operating a PCS in an optimal efficiency zone in an integrated system that combines an energy storage device (ESS) and a charger. [Background technology]

[0002] An energy storage system (ESS) is a device that stores electricity in a battery and then supplies it to the grid. Energy storage devices can be charged and discharged. In recent years, as the use of electric vehicles has expanded, electric vehicle chargers have been installed in various spaces. However, the use of electric vehicle chargers increases the amount of electricity used on the grid and can affect the amount of electricity used in other areas. In particular, there is a problem that the use of electric vehicle chargers is limited when electricity usage increases sharply.

[0003] Therefore, there is a need for a method to provide a system that can stably charge the battery in the space where the charger is installed. Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide an electric vehicle charging system in which an energy storage device assists the charger's power usage to stabilize the grid's power supply and is driven in cooperation with ESS power.

[0005] Another problem to be solved by the present invention is to provide control so that power conversion is performed according to a specific charge / discharge range of the VIB ESS so as to satisfy the optimum efficiency range of the PCS in consideration of power efficiency.

[0006] The problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned here will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0007] According to an embodiment of the present invention, there is provided a power control system including: an energy storage system (ESS) connected to a power grid and having a battery; a power conversion system (PCS) operatively connected to the power grid and the energy storage system (ESS); and a control unit that provides control to perform charging and discharging procedures for the battery by giving priority to power conversion efficiency of the power conversion system (PCS).

[0008] According to an embodiment of the present invention, there is provided a power conversion device efficiency control system including: a VIB ESS (Vanadium-ion Battery Energy Storage System); a power conversion system (PCS) connected to a power grid and the VIB ESS; and a power conversion device operatively connected to the PCS, wherein the power conversion device controls power conversion according to a specific charge / discharge range of the VIB ESS to satisfy an optimum efficiency range of the PCS in consideration of power efficiency.

[0009] According to an embodiment of the present invention, there is provided a method for controlling a power conversion device, which uses a power conversion device that controls the transmission of at least one of power from a power grid and power from an energy storage device (ESS) to an electric vehicle charging system and adjusts charging and discharging of the ESS according to the electric vehicle charging speed, thereby providing operational control to correspond to an optimal efficiency range for power conversion, and the power conversion device controls the power conversion according to a specific charging and discharging range of the ESS to satisfy the optimal efficiency range of a power conversion system (PCS) connected to the ESS, taking into account power efficiency. [Effects of the Invention]

[0010] When implementing an embodiment of the present invention, the energy storage device can assist the charger in using power to stabilize the grid power supply, thereby enabling the charger to provide stable electric vehicle charging services.

[0011] When implementing an embodiment of the present invention, control can be provided so that power conversion is performed according to a specific charge / discharge range of the VIB ESS to satisfy the optimum efficiency range of the PCS in consideration of power efficiency.

[0012] The effects provided by the present invention are not limited to those mentioned above, and other effects not mentioned here will be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawings]

[0013] [Figure 1(a)] FIG. 1 illustrates a power supply configuration with a power grid, energy storage devices, and other electrical devices relevant to an embodiment of the present invention. [Figure 1(b)] FIG. 10 shows the corresponding outputs at points A, B, and C over time. [Figure 1(c)] FIG. 1 is a conceptual configuration diagram related to an embodiment of the present invention. [Figure 2(a)] FIG. 2 is a diagram illustrating a charger output, an ESS output, and an ESS state of charge (SoC) according to an embodiment of the present invention. [Figure 2(b)] FIG. 2 is a diagram illustrating a charger output, an ESS output, and an ESS state of charge (SoC) according to an embodiment of the present invention. [Figure 2(c)] FIG. 2 is a diagram illustrating a charger output, an ESS output, and an ESS state of charge (SoC) according to an embodiment of the present invention. [Figure 3(a)] 10 is a graph showing the output of ultra-fast charging mode 1 for a charger 360 of a power supply system 300 according to an additional embodiment of the present invention. [Figure 3(b)] FIG. 3(b) is a conceptual diagram showing power supply in phase 1 and phase 2 of FIG. [Figure 4(a)]10 is a graph showing the output of ultra-fast charging mode 2 for a charger 360 of a power supply system 300 according to an additional embodiment of the present invention. [Figure 4(b)] FIG. 4(b) is a conceptual diagram showing power supply in phase 1 and phase 2 of FIG. 4(a). [Figure 5] FIG. 1 is a diagram showing a configuration in which an energy storage device is arranged in a space according to one embodiment of the present invention and a configuration in which it supplies power to other electrical devices. [Figure 6] FIG. 1 illustrates a configuration in which a charger according to an embodiment of the present invention is powered by an energy storage device and a power distribution device. [Figure 7] 1 is a diagram illustrating the configuration of an energy storage device according to an embodiment of the present invention. [Figure 8] FIG. 10 is a diagram illustrating a process in which a controller according to an embodiment of the present invention controls an energy storage device according to the amount of power in a grid. [Figure 9] 1 illustrates the arrangement and operation of an energy storage device and charger according to one embodiment of the present invention. [Figure 10] 10A and 10B illustrate the arrangement and operation of an energy storage device and a charger according to another embodiment of the present invention. [Figure 11] 10 is a diagram illustrating a process in which an energy storage device operates in response to an increase in power usage in a grid according to an embodiment of the present invention. [Figure 12] FIG. 10 is a diagram illustrating the configuration of an energy storage device according to another embodiment of the present invention. [Figure 13] 1 is a diagram showing the configuration of a charger according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0014] The advantages and features of the invention presented herein, and methods for achieving them, will become clearer with reference to the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed herein, and may be realized in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully convey the scope of the invention to those skilled in the art to which the present invention pertains. The present invention is defined solely by the scope of the claims. The same reference numerals may refer to the same elements throughout the specification.

[0015] Furthermore, when describing the present invention, if it is determined that a detailed description of related publicly known structures or functions may obscure the gist of the present invention, such detailed description may be omitted.

[0016] Furthermore, terms such as first, second, A, B, a, and b may be used to describe components of the present invention. These terms are merely used to distinguish the component from other components, and do not limit the nature, order, sequence, or number of the components. When a component is described as being "connected," "coupled," or "connected" to another component, it should be understood that the component can be directly connected or connected to the other component, but that other components may be "intervening" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0017] Hereinafter, this specification describes a technology in which an energy storage device installed in a space such as a building, a house, a subway, or a public place controls charging and discharging of the energy storage device according to the electricity usage status of other electrical devices in the space. Also, a technology in which the energy storage device controls a charger according to the electricity usage status is described. Finally, a technology in which the energy storage device supplies power to other electrical devices in the space when the power usage load of the other electrical devices increases is described.

[0018] Generally, an energy storage system (ESS) is composed of a battery, a battery management system (BMS), a power conversion system (PCS), an energy management system (EMS), etc. A battery has one or more cells, and multiple cells form a module, and multiple modules can form a rack. An energy storage system (ESS) configured in this way can be connected to a power grid, electrical network, or power grid to receive power.

[0019] Energy storage systems (ESS) can be used to charge electric vehicles (EVs). The batteries used in ESSs and the batteries used inside EVs each have a state-of-charge (SoC), the background of which is as follows:

[0020] First, we need to understand the battery charge / discharge rate (C-Rate). The charge rate and / or discharge rate of a battery can be controlled by the charge / discharge rate (C-Rate). The charge / discharge rate (C-Rate) is a measurement of the current used to charge and / or discharge a battery. For example, a particular battery discharging at 1C-Rate or 1C means that a battery with a capacity of 10Ah (i.e., the amount of electricity when 10A (amperes) of current flows in 1 hour) can discharge 10A (amperes) from a fully charged state in 1 hour. In this way, the battery charge rate can also be expressed as a C-Rate.

[0021] By measuring a battery being charged at a specific C-Rate, you can check the corresponding State of Charge (SoC).When charging an electric vehicle (EV) using an energy storage system (ESS), you can check the SoC of the battery inside the ESS and the SoC of the battery inside the electric vehicle (EV) and perform various controls related to charging. The embodiments of the present invention described below relate to system control required for charging an electric vehicle (EV) using an integrated system that applies an EV charger to an energy storage system (ESS), and the present inventors will present technically improved features in comparison with conventional or existing energy storage system (ESS) system configurations and controls. The features of the present invention can also be expressed as an EV charging system operated in conjunction with ESS power.

[0022] The features of the present invention will now be described in more detail with reference to examples. FIG. 1(a) is a diagram showing a power supply configuration between a power grid 110, an energy storage device 140, and other electric devices 120, 130, 150, 160, and 170 in a power supply system 100 according to an embodiment of the present invention.

[0023] Generally, a power supply system 100 includes a main distribution board 120 that receives power, i.e., alternating current (AC), from a power grid 110, and distributes the power to a power conversion system (PCS), power bank, or similar power conversion equipment 130. Meanwhile, the main distribution board 120 may also be connected to an ESS external load 170 to supply power.

[0024] The power conversion equipment 130 is operatively connected to an energy storage device 140, such as a VIB ESS, and can transmit or receive power by providing necessary control. The power conversion equipment 130 is also connected to a charger 150, which can be connected to an electric vehicle (EV) 160 or other object that needs to be charged. The electric vehicle (EV) 160 can selectively receive power from at least one of the power grid 110 and the energy storage device 140 under the control of the power conversion equipment 130.

[0025] Here, at least one of the main distribution board 120, power conversion equipment 130, energy storage device 140, charger 150, electric vehicle 160, and ESS external load 170 can be installed in a designated location, for example, inside or adjacent to a specific building.

[0026] It is desirable that such a power supply system 100 be installed and controlled so that it can supply grid power to a specific building and also charge electric vehicles. Therefore, the outputs for the portions indicated by A, B, and C in FIG. 1(a) will be explained in more detail in FIG. 1(b).

[0027] FIG. 1(b) is a conceptual diagram for explaining the output for the portions indicated by A, B, and C in FIG. 1(a) described above. Figures 1(a) and 1(b) show a configuration that combines an ESS and a charger, and correspond to a technology in which the ESS assists so as not to exceed the grid's contracted power, and the ESS charges after charging is completed.

[0028] The graph of output A shows the charger output over time, and the electric vehicle is charged while receiving power from the grid and ESS. The highest output is observed at the beginning and initial stage of the electric vehicle charging, and as time passes, the charger output decreases, reaching a minimum level as the end of the electric vehicle charging approaches. The contracted power associated with the grid is shown at a constant level for illustrative purposes, and will be described in more detail below.

[0029] The graph of output B shows the grid output over time, with the highest output occurring at the beginning and initial stage of charging the electric vehicle, and the charger output decreasing as time passes, reaching a minimum level as the electric vehicle charging nears its end.

[0030] The graph of output C shows the ESS output over time, with the maximum output occurring at the beginning and initial stage of charging the electric vehicle, then the charger output decreasing over time and reaching a minimum level as the end of charging approaches. Here, the maximum output of the ESS is the value obtained by subtracting the grid contract power mentioned above from the maximum output of the charger.

[0031] FIG. 1(c) is a conceptual configuration diagram related to an embodiment of the present invention. To charge an electric vehicle, power is provided from the power grid and supplied to the electric vehicle charger after the corresponding AC / DC conversion. When an energy storage device (ESS) charges and discharges while supplementing the grid power, a switching circuit is included in the corresponding AC / DC conversion unit, allowing the energy storage device to switch between charging and discharging during the electric vehicle charging procedure.

[0032] Therefore, it can be said that an embodiment of the present invention provides an electric vehicle charging method, which receives power from at least one of a power grid and an energy storage device, performs a charging procedure through a charger, and is capable of switching between discharging and charging the energy storage device depending on the state of the power grid during the electric vehicle charging procedure.

[0033] Next, the relationship between the output of the charger and the output and state-of-charge (SoC) of the ESS will be described in more detail. FIG. 2(a) is a conceptual diagram showing the relationship between the output of the charger, the output of the ESS, and the state of charge (SoC) according to the first embodiment of the present invention.

[0034] Following the explanation of Figures 1(a) through 1(c) above, this figure shows a case where, when charging the first EV (electric vehicle), a charger output exceeding the grid's contracted power is required, and the EV is initially charged using the ESS output. Over time, the ESS's sustained discharge reduces the charger's output, and in the range below the grid's contracted power, charging continues using the grid's power until the first EV is fully charged. If the second EV is then immediately charged, the ESS discharge prevents immediate use. In other words, measuring the ESS's SoC reveals that the SoC reaches nearly 0% by the time the first EV is fully charged.

[0035] If EV charging begins when the ESS is fully charged, the ESS will provide support, allowing charging at maximum output. If the ESS capacity is similar to the amount of power it provides to support the EV, it may be difficult to provide support for a second EV after charging one. To solve this problem, the ESS capacity can be increased, but this increases overall costs and reduces profitability. Another option is to recharge the ESS, but this reduces profitability as the number of EVs being charged decreases due to waiting time during recharging.

[0036] On the other hand, it can be seen that there is an area in the latter half of the first EV charging where the grid contracted power is wasted. In response to this, the inventors of the present invention recognized the problem of such a wasted area and conducted research and development into a technical solution that can improve it.

[0037] FIG. 2(b) is a conceptual diagram showing the relationship between the output of a charger, the output of an ESS, and the state of charge (SoC) according to an additional embodiment of the present invention. To explain the background, the electrochemical characteristics of the lithium batteries (LIBs) currently used to charge electric vehicles allow for fast charging at low SoC, but once the SoC exceeds a certain level, the charging speed slows down for safety reasons. Even when an ultra-fast charger is used, ultra-fast charging only occurs in the initial section, and after a certain point, the EV charging process becomes unsatisfactory. In other words, the ESS that supports the power grid must supply optimal power according to the amount of power required by the electric vehicle, and VIBs, with their wide charge / discharge rate (C-rate) coverage, are considered to be the battery optimized for ESS.

[0038] Therefore, the inventors developed a charging system that simultaneously charges and discharges the ESS while charging an electric vehicle. That is, they devised a system in which the ESS discharges in the electric vehicle fast charging section to supplement power from the power grid, and then charges the ESS according to the state of the power grid when the electric vehicle enters the slow charging section. As a result, the system can be said to have a certain difference in the ESS SoC between when the electric vehicle starts charging and when the electric vehicle finishes charging.

[0039] In addition, the inventors have found that since the charge / discharge output varies greatly depending on the state of the power grid, VIB ESS, which can handle a wide range of outputs from low to high, is suitable.

[0040] The present inventors propose to use the area where the grid contracted power shown in FIG. 2(a) is wasted for VIB ESS charging. Here, charging can be performed for at least one battery, at least one cell, at least one module, and / or at least one rack in the VIB ESS.

[0041] First, when electric vehicles are continuously being charged, if the charger output falls below a certain reference value, such as the contracted power (of the power grid), the remaining surplus output can be used to charge the ESS. By performing the necessary control, the ESS's SoC remains unchanged from the time the first EV charging ends until the next second EV charging occurs. In other words, the inventors have devised a charging system that allows EV users to always use the best charger, supplies grid power to a specific building, and performs both charging and discharging of the ESS during the electric vehicle charging process, allowing electric vehicles to be charged at the same time.

[0042] In this case, a VIB with a long lifespan is advantageous because the ESS requires a full charge and discharge cycle for each EV. Charger operators may be able to maintain maximum charging speeds even when using an ESS with half the capacity of an EV.

[0043] FIG. 2(c) is a conceptual diagram showing another relationship between the output of the charger, the output of the ESS, and the state of charge (SoC) according to an additional embodiment of the present invention. If electric vehicle charging is interrupted midway, some EV users may stop charging if the charging speed drops below a certain level. Therefore, it may be necessary to reserve some time for ESS charging or to reduce the maximum output to a certain level while the ESS is charging.

[0044] This is shown as a short standby time region in Figure 2(c), and the relationship between the corresponding charger output, ESS output, and ESS SoC is shown. If electric vehicle charging ends before the reference value for switching from ESS discharging to charging is reached, control is executed to resume ultra-fast charging after ensuring a certain amount of time for ESS charging.

[0045] Alternatively, if the electric vehicle charging is terminated before the reference value for switching from ESS discharging to charging is reached and ultra-fast charging is immediately started, control is performed to adjust the electric vehicle ultra-fast charging power downward. For example, this control can be performed when the ESS is difficult to discharge.

[0046] An additional embodiment of the present invention will now be described in more detail with reference to Figures 3(a), 3(b), 3(c), 4(a) and 4(b). A battery management system or battery control system has efficiency for the battery itself and efficiency for the power conversion device. Battery efficiency refers to the efficiency of the input to output of the battery. More specifically, it refers to the efficiency of the battery's charge capacity to its dischargeable capacity. In the case of an AC / DC converter, the higher the output power, the better the efficiency. In the case of a DC / AC inverter, the higher the DC voltage, the better the efficiency.

[0047] Here, in AC / DC converter operation, switching control is performed and power control is possible according to the switching speed. When outputting low power, the switching speed is low, and when outputting high power, the switching speed is high. Therefore, in order to control the efficiency of the power conversion device, it is necessary to use power above a certain level.

[0048] Therefore, in order to control the efficiency of the power converter, a battery voltage above a certain level must be used. However, conventional power conversion devices have efficiency issues, resulting in excessive power loss and waste. The inventors of the present invention have recognized a specific problem: power loss increases even more during low-power output, and the loss rate is excessive in conventional battery management system operation methods that do not consider power efficiency due to output limitations based on battery status (or performance). Based on this recognition, the inventors have focused on technology that can solve the conventional problems and operate the system by utilizing the optimal efficiency range of the power conversion device by applying the vanadium-ion battery (VIB) that the inventors are researching and developing to the battery management system and operating the system with improved control and / or a method that is more advanced than conventional methods.

[0049] Compared to lithium-ion batteries (LIBs), vanadium-ion batteries (VIBs) have superior output range, stability, and usable charge / discharge rate (C-rate) range. Experimental measurements have shown that vanadium-ion batteries currently have the highest efficiency between 0.2C and 1.0C. That is, efficiency is relatively better in the 0.2C to 1.0C range compared to below 0.2C and above 1.0C. This range is exemplary, and the wider efficiency range between 0.2C and 10C can also be seen as a feature of the present invention. Furthermore, the optimal efficiency range for vanadium-ion batteries may change as technological developments progress. While such vanadium-ion batteries are fully capable of high C-rate input and output, it can also be seen as desirable to operate them at optimal efficiency.

[0050] It can be seen that conventional technology performs charge / discharge control centered on battery performance and does not consider power efficiency. In contrast, the present invention performs special control over the standby process after charging at a voltage above a certain level for more efficient battery discharge. In addition, the inventors have developed battery technology that charges at the optimal amount of power according to the specifications of the power conversion device for efficient battery charging. More specifically, in some embodiments, efficiency can be maximized by charging a vanadium ion battery (VIB) at a value between 0.2C and 1.0C.

[0051] Hereinafter, with reference to Figures 3(a) to 3(c), the efficiency control of the power conversion device will be further explained by comparing the case of an energy storage device (ESS) using a lithium ion battery (LIB) with the case of an energy storage device (ESS) using a vanadium ion battery (VIB).

[0052] 3(a) shows a conceptual diagram of an energy storage system (ESS) using a lithium-ion battery (LIB) receiving power from a power grid through a power conversion system (PCS). For example, the power supplied from the AC grid is converted by the PCS to a range of 14kW to 35kW, allowing the LIB ESS to charge and discharge in a range of 20A to 50A.

[0053] The characteristics of the lithium-ion battery (LIB) used in the LIB ESS include an optimal battery efficiency range of 0.2C to 0.5C, which corresponds to the stable range of the LIB, with a 1C-Rate of 100A and a current voltage of 700V. The PCS connected to such a LIB ESS includes a power conversion device that can perform optimal efficiency control, and theoretically can control charging and discharging in the range of 20A to 50A based on the battery, and can also theoretically control power conversion in the range of 14kW to 35kW. As a result, the optimal efficiency range of the PCS can be considered to be in the range of 50kW to 100kW.

[0054] However, in the case of LIBs, the amount of power conversion is determined by the performance of the lithium battery, making it virtually impossible to control the efficiency of the power conversion device. As a result, the power conversion device cannot achieve optimal efficiency, and as a result, power loss is unavoidable.

[0055] Figure 3(b) shows a conceptual diagram of the same PCS as in Figure 3(a) above, with all other conditions remaining the same, but with a VIB instead of a LIB. Due to the electrochemical characteristics of a VIB, the battery's optimum efficiency range is wider than that of a LIB, ranging from 0.2C to 1C. The 1C-rate is 100A and the current voltage is 700V, the same as in the case of a LIB. Furthermore, with the same PCS applied, the optimum efficiency range for the PCS is between 50kW and 100kW.

[0056] However, unlike LIBs, the PCS connected to the VIB ESS includes a power converter, which can perform optimal efficiency control, controlling charging and discharging in the range of approximately 70A to 100A based on the battery, and controlling power conversion in the range of approximately 50kW to 80kW, thereby satisfying the PCS's optimal efficiency range (50kW to 100kW).This is because the higher the ESS voltage during VIB discharge, the more efficient the power conversion.

[0057] Figure 3(c) shows the same conceptual diagram as Figure 3(b) above, but with a higher specification PCS applied. As a result, the battery optimal efficiency range (0.2C~1C), 1C-Rate (100A), and current voltage (700V) are the same as in Figure 3(b), but the PCS optimal efficiency range is wider, from 100kW to 200kW.

[0058] Therefore, the power conversion device of the PCS connected to the VIB ESS can be controlled to charge and discharge in the range of approximately 140A to 290A based on the battery, and can be controlled to perform power conversion in the range of approximately 100kW to 200kW, thereby satisfying the optimal efficiency range (100kW to 200kW) of a high-spec PCS.

[0059] Here, the optimal battery efficiency range for VIBs, 0.2C to 1C, is relatively good, and due to the electrochemical characteristics of VIBs, they can be used in ranges above that. The VIB's output-to-input efficiency is best between 0.2C and 1C, but this does not mean that it is inefficient below 0.2C or above 1C. Regardless of the PCS output, the VIB can operate stably, and because the VIB has higher efficiency than the PCS's power loss, it is possible to control the amount of charging power by prioritizing the PCS power conversion efficiency. In other words, the amount of power conversion is not determined by the performance of the applied battery, but rather operation is possible in the optimal efficiency range by prioritizing the power conversion device, and unlike the case of LIBs, it is possible to control the efficiency of the power conversion device.

[0060] Therefore, by utilizing the features of the present invention, it is possible to operate the PCS in the optimum efficiency range. The charging and discharging sequence of the VIB battery will be explained below. FIG. 4(a) is a flow chart illustrating a VIB battery charging sequence S4000 according to at least one embodiment of the present invention.

[0061] First, steps S4010 to S4030 indicated by dotted lines can be executed when it is assumed that there is a surplus of grid power. That is, the maximum amount of power available to the grid is saved in S4010, the contracted amount of power is saved in S4020, and the amount of available power or power being used is checked in S4030. Here, various amounts of power can be checked using monitoring means, devices, sensors, measuring instruments, etc., and the corresponding amounts of power can be saved in storage means such as memory or storage device.

[0062] Generally, the battery voltage is first checked in step S4040. Next, the optimal battery charging energy amount is calculated in step S4050 (battery voltage x optimal charging current). The calculated energy amount is then compared with the grid power margin in step S4060. If the grid power margin is insufficient, the system can return to the battery voltage checking step S4040, or it can wait until the grid power margin is reached.

[0063] Then, it is determined whether the battery charging power amount conforms to the PCS optimum efficiency section (S4070), the charging power is set based on the calculated power (S4080), and charging is started (S4090). If it is determined in the compatibility determination step S4070 that the PCS efficiency range is greater than the battery power capacity, the charging power is set to the PCS minimum efficiency range S4072 and charging is started S4090. Alternatively, if it is determined that the PCS efficiency range is less than the battery power capacity, the charging power is set to the PCS maximum efficiency range S4074 and charging is started S4090.

[0064] According to the flowchart of FIG. 4, the charging process of the VIB battery can be performed according to the VIB battery optimum efficiency section and the PCS optimum efficiency section of FIG. 3(b) or FIG. 3(c).

[0065] FIG. 4(b) is a flow chart illustrating a VIB battery discharge sequence S5000 according to at least one embodiment of the present invention. First, steps S5010 to S5030 indicated by dotted lines can be executed when it is assumed that there is a surplus of grid power. That is, the maximum amount of power available to the grid is saved S5010, the contracted amount of power is saved S5020, and the amount of available power or power being used is checked S5030. Here, various amounts of power can be checked using monitoring means, devices, sensors, measuring instruments, etc., and the corresponding amounts of power can be saved in storage means such as memory.

[0066] Generally, the grid power status is first checked S5040. If it is confirmed that the grid power is insufficient, the discharge power is set to the PCS maximum efficiency section S5041, and the battery discharge starts S5043.

[0067] If the grid power is found to be sufficient, the battery voltage is checked (S5042). If the optimal discharge voltage is found, the process returns to the step of checking the available power or the amount of power being used (S5030) and checks the grid power status again (S5040). If the efficient discharge voltage is found to be insufficient, the charging logic control is executed (S5044).

[0068] In other words, when the grid power is insufficient, the power converter discharges in the maximum efficiency range, and when there is a surplus of grid power and the battery voltage is not the optimal discharge voltage, the charging logic is executed. Therefore, the battery voltage is increased even slightly to prepare, allowing for optimally efficient power conversion.

[0069] According to the flowchart of FIG. 4(b), the VIB battery discharge process can be performed according to the VIB battery optimum efficiency section and PCS optimum efficiency section of FIG. 3(a) or FIG. 3(b).

[0070] As mentioned above, in the contents and related explanations of Figures 3(a), 3(b), 3(c), 4(a), and 4(b), various types of power consumption can be confirmed and compared using monitoring means, devices, sensors, measuring instruments, power meters, etc., and the transmission and reception of the relevant power consumption information can be carried out using wired communication or wireless communication equipment and technology such as Wi-Fi.

[0071] 5 is a diagram showing a configuration in which an energy storage device is disposed in a space and a configuration for supplying power to other electrical devices according to an embodiment of the present invention. FIG. 1 shows an energy storage system (ESS) 100 and other devices. A grid corresponding to a power source 10 can supply power to a supportive power region 30 and a primary power region 40. The energy storage device (ESS) 100 can be disposed in the supportive power region 30.

[0072] An energy storage device (ESS 100) and one or more chargers 50a, ..., 50n can be located in the supportive power domain 30. A number of electrical devices 60a, ..., 60n can be located in the primary power domain 40. Also, a separate ESS, distinct from the energy storage device 100 located in the supportive power domain 30, can be located in the primary power domain 40.

[0073] 5, power distribution device 20 can distribute power to supportive power domain 30 and primary power domain 40. Energy storage device 100 can be charged or discharged according to the electrical demand or predicted demand in the two domains 30, 40. To this end, power meter 210 can be connected to or disposed within supportive power domain 30. Also, power meter 220 can be connected to or disposed within primary power domain 40.

[0074] The power measuring devices 210 and 220 are, for example, power meters, and measure the amount of power being used in the area where they are installed. The power measuring devices 210 and 220 transmit the measured value (amount of power) to the energy storage device 100. Furthermore, according to an embodiment of the present invention, a separate power measuring device may be installed in the power source 10. In this case, the energy storage device 100 can check the amount of power consumed by the power source 10 in real time.

[0075] In this specification, the energy storage device includes an energy storage device including a vanadium ion battery, but the present invention is not limited thereto. For example, the energy storage device in this specification includes a VRB (Vanadium Redox Battery), a PSB (Polysulfide Bromide Battery), a ZBB (Zinc Bromine Battery), etc.

[0076] 5, when charger 50 charges an electric vehicle or other device requiring charging, it can perform charging according to the charging conditions required by the electric vehicle or other device. For example, if high current charging is requested, charger 50 performs high current charging. Power from power source 10 and energy storage device 100 is provided to charger 50 under the control of energy storage device 100. When charger 50 performs low current charging, energy storage device 100 can supply power to charger 50 from power source 10 according to the power supply status of power source 10 or the power usage status of primary power domain 40.

[0077] FIG. 6 is a diagram showing a configuration in which a charger according to an embodiment of the present invention is supplied with power from an energy storage device 100 and a power distribution device 20. The charger 50 can be supplied with power P1 from the power distribution device 20. In one embodiment, this is supplied with power from the grid, i.e., the power source 10. The energy storage device 100 can compare information about the amount of power received from the power meters 211, 212, and 220 with the maximum amount of power that can be provided by the corresponding power source 10, and can subsidize part or all of the amount of power used by the charger 50.

[0078] The energy storage device 100 can supply power to the charger 50 (P2). The charger 50 can switch or merge the power supplied under the control of the energy storage device 100. The charger 50 can supply power according to a charging request from an external device (P5).

[0079] The energy storage device 100 can receive power from the power distribution device 20 (P3). The energy storage device 100 can then supply power to the primary power domain 40 (P4). The power supplied by the energy storage device 100 can be supplied to the primary power domain 40 via the power distribution device 20. That is, the power supply direction between the energy storage device 100 and the power distribution device 20 can be bidirectional.

[0080] The power supply P4 of the energy storage device 100 may be determined based on the power demand of the primary power domain 40, the maximum amount of power that the power source 10 can supply, and the like. When the energy storage device 100 supports the fast charging and discharging function of the charger 50, the energy storage device 100 can monitor the amount of power in the grid 10 and flexibly respond to the power situation in the grid 10. In particular, the energy storage device 100 can accumulate and store information about past power usage times in the grid 10 and predict time periods when power usage in the grid 10 is low. As a result, the energy storage device 100 can prepare for a sudden increase in power usage in the grid 10 during the fast charging and discharging process of the charger 50.

[0081] The above process can also be applied when high-speed charging of the energy storage device 100 is required. That is, the energy storage device 100 receives power from the grid 10 and can perform high-speed charging of the energy storage device 100. In this process, the amount of power in the grid 10 can be monitored as described above, and the system can flexibly respond to the power situation in the grid 10.

[0082] 7 is a diagram showing the configuration of an ESS according to an embodiment of the present invention. The energy storage device 100 includes an energy storage module 110 including a battery and a controller 150.

[0083] The energy storage device 100 includes a Pack BMS 120 that manages charging and discharging of the energy storage module 110. The energy storage device 100 may also optionally include a Power Management System (PMS) 130 and a Power Conversion System (PCS) 140. When the energy storage device 100 includes both the PMS 130 and the PCS 140, it may be referred to as an integrated ESS.

[0084] The module BMS manages the battery by monitoring the charge state, discharge state, temperature, voltage, current, etc. The pack BMS 120 is a battery management system for the entire battery pack.

[0085] The controller 150 can use the power measurement results from the supportive power domain and the power measurement results from the primary power domain to determine whether to charge or discharge the energy storage module 110, or to determine whether to discharge to one or more chargers located in the supportive power domain or the primary power domain. In one embodiment, the controller 150 can be integrated with the PMS 130 and operate as a single component.

[0086] FIG. 8 is a diagram illustrating a process in which a controller controls an energy storage device according to the amount of power in a grid according to an embodiment of the present invention. The controller 150 can store the maximum power amount (Grid_Max) of the grid that supplies power to the primary power domain and the supportive power domain, i.e., the power source 10 (S301). The maximum power amount (Grid_Max) means the maximum amount of power that can be used in the grid.

[0087] Thereafter, the power meter 220 measures the power usage (Primary_Usage) of the primary power domain 40 (S302). In one embodiment, this is to measure the power usage (load usage) generated in a domain other than the supportive power domain 30 where the energy storage device 100 is located.

[0088] According to another embodiment of the present invention, in step S302, the energy storage device 100 or the controller 150 may receive the power consumption of the entire grid and the power usage of the primary power domain.

[0089] Next, the controller 150 determines whether a charger 50 located in the supportive power region 30 is in use (S303). If there are multiple chargers 50, the controller 150 can determine whether each charger 50 is in use. If a charger 50 is not in use, the controller 150 executes step S307. The controller 150 compares the amounts of power (S307), and compares Grid_Max with Primary_Usage. If Grid_Max is greater than or equal to Primary_Usage, the controller 150 determines the amount of ESS charging and proceeds with charging (S311).

[0090] The controller 150 then measures the SOC (State of Charge) of the ESS (S312), and terminates charging if the SOC is equal to or greater than the reference value. On the other hand, the controller 150 measures the SOC of the energy storage device 100 (S312), and if the SOC is equal to or less than the reference value, repeats the steps from S302 onward to control charging of the ESS.

[0091] On the other hand, if Grid_Max is less than Primary_Usage in S307, the controller 150 determines the amount of discharged power of the energy storage device 100 and controls the energy storage device 100 to discharge to the primary power domain 40 in S313. As a result, the excess grid power is replenished by the discharge of the energy storage device 100.

[0092] If the charger is in use in S303, the controller 150 measures the charger requested power amount (Charging_Request) in S304. At this time, it is assumed that the SOC of the ESS is equal to or greater than the reference value. The controller 150 then compares the power amounts (S305) and compares the sum of Charging_Request and Primary_Usage (Charging_Request + Primary_Usage) with Grid_Max.

[0093] If the comparison result shows that Grid_Max is less than Primary_Usage+Charging_Request, the controller 150 determines the amount of discharged power of the energy storage device 100 and controls the energy storage device 100 to discharge to the primary power domain 40 (S313). As a result, the excess grid power is replenished by the discharge of the energy storage device 100.

[0094] Furthermore, if the comparison result in S305 shows that Grid_Max is equal to or greater than Primary_Usage+Charging_Request, the controller 150 checks whether the difference (the amount of grid power margin, see Equation 1 below) is equal to or greater than a grid margin reference value in S306.

[0095] [Formula 1] Grid margin = Grid_Max - (Primary_Usage + Charging_Request) If the amount of grid power margin is equal to or greater than the grid power margin reference value, the amount of power is sufficient, so the controller 150 determines the amount of power to be charged to the energy storage device 100 and controls the energy storage device 100 to charge S314, which means that the energy storage device 100 is charged with the amount of grid power that is sufficient for charging.

[0096] On the other hand, if the grid's power margin is less than the grid margin reference value, it is highly likely that the grid's power will not be able to meet the power demand of the supportive power region 30 and the primary power region 40 in the future, so the controller 150 transitions the energy storage device 100 to a discharge standby mode S315.

[0097] In steps S311 and S314 of charging the ESS in Figure 8, the controller 150 can perform a high current charging process for the battery. The controller 150 continuously receives the power measurement results for the primary power domain, and if the grid's available power becomes low, it can charge the battery at low current or transition to discharge standby mode as in S315. Of course, even in discharge standby mode, the controller 150 can monitor the overall grid power status and the battery's SOC to determine whether to perform low current or high current charging of the battery.

[0098] FIG. 9 illustrates the arrangement and operation of an ESS and a charger according to an embodiment of the present invention. FIG. 8 illustrates a configuration in which a vanadium ion battery (VB) ESS (VIB ESS) 100a, which is an embodiment of an ESS, is installed. The electricity supply process is in the order of a power source 10 (the grid), a substation room 5, a power meter 205, and a power distribution device 20a (an embodiment of a main distribution board). Electricity is supplied from the power distribution device 20a to the VIB ESS 100a, the charger 50, and loads outside the ESS. A power meter 205 is installed on the grid main power line, and power meters 211, 212, and 220 may be installed on each line in each of the areas 30a and 40a. Information about power consumption by each area and overall is transmitted to the VIB ESS 100a.

[0099] As shown in FIG. 8, the VIB ESS 100a stores information about the maximum amount of power (Grid_Max) that can be used in the grid. The VIB ESS 100a can also receive information about the amount of power supplied to loads outside the ESS (e.g., the amount of power being used in 40a) from the power meter 220 located in 40a. In one embodiment of the present invention, the VIB ESS 100a can also receive the amount of power consumed by the entire grid (Grid_Usage) from the power meter 205.

[0100] The reception method can be either periodic reception or real-time reception. In the case of periodic reception, the period can be changed according to changes in the amount of power used in the primary power region 40a. For example, the controller 150 can set the reception period to 5 minutes at night when there is little change in the amount of power, and to 1 minute at daytime when there is a large change in the amount of power.

[0101] The VIB ESS 100a can control charging or discharging of the VIB ESS 100a so that grid power usage is optimized according to the amount of power used in the primary power domain 40a. The VIB ESS 100a's operating modes include a charging mode, a discharging mode, and a standby mode. In the charging mode, the VIB ESS 100a determines the ESS charging amount, proceeds with charging according to the ESS's SOC reference value, and then terminates the charging mode.

[0102] In addition, the VIB ESS 100a can also subsidize all or part of the amount of power output by the charger 50 (P11). For example, if the value (available power amount) obtained by subtracting the amount of power used in the primary power domain 40a from the maximum amount of power on the grid is smaller than the amount of power output by the charger 50 (a shortage of charger charging power occurs), the VIB ESS 100a can subsidize the shortage or an amount of power greater than the shortage.

[0103] In addition, if Grid_Usage is at or exceeds Grid_Max and grid power is cut off, the VIB ESS 100a can discharge the amount of power charged to the primary power domain 40a. For example, if the VIB ESS 100a discharges power to the power distribution device 20a as in P10, the power distribution device 20a can supply this power to the primary power domain 40a.

[0104] In addition, the VIB ESS 100a can also subsidize all or part of the amount of power output by the charger 50 (P11). For example, if the value (available power) obtained by subtracting the total grid power consumption (Grid_Usage) from the grid maximum power is smaller than the amount of power output by the charger 50 (a shortage of charger charging power occurs), the VIB ESS 100a can subsidize the shortage or an amount of power greater than the shortage.

[0105] 9, the VIB ESS 100a can optimize the amount of power in the grid according to the power usage status in the grid. For example, the VIB ESS 100a can supplement the amount of power to minimize losses due to excessive peak power and suppress grid overload.

[0106] Therefore, the controller 150 of the VIB ESS 100a can determine whether to charge the battery at high current or low current after receiving the power measurement result of the primary power domain. If the power amount in the primary power domain is below a certain level (e.g., below 80%) compared to the total grid usage, the VIB ESS 100a can be quickly charged through high current charging.

[0107] On the other hand, if the amount of power in the primary power domain exceeds a certain standard (e.g., 80% or more) compared to the total grid usage, the VIB ESS100a is continuously charged through low-current charging to reduce the load on the entire grid, and the charged power can be used to supplement grid power in the future.

[0108] Figure 10 is a diagram showing the arrangement and operation of an ESS and charger according to another embodiment of the present invention. The configuration of Figure 10 differs from that of Figure 9 in that the power distribution device 20a functioning as a main distribution board and the power distribution device 20b functioning as an ESS distribution board are separated. In addition, a power distribution device 20c functioning as a DC distribution board (container) for supplying power to the VIB ESS 100b is separately arranged.

[0109] The power distribution device 20c may be configured as one or more separate units, and the present invention is not limited to a specific configuration of the power distribution device. The power distribution device 20c may be selectively arranged depending on the configuration and arrangement of the VIB ESS 100b.

[0110] 10 shows the PMS 130b and the PCS 140b separately, the present invention is not limited thereto, and the PMS 130b and the PCS 140b may be configured within the VIB ESS 100b. The PMS 130b may be integrated with the controller 150 described above to control the operation mode, such as charging or discharging, of the VIB ESS 100b.

[0111] Furthermore, the power bank 51 may be a component of the charger 50 or may be a component independent of the charger 50, depending on the implementation method of the invention. In the configuration of FIG. 9, the VIB ESS 100a can supplement the power of the entire grid. The VIB ESS 100b stores information about the maximum output of the power grid. The VIB ESS 100b can receive the amount of power consumed by the entire grid from the power meter 205. Alternatively, the VIB ESS 100b can receive a measured value of load usage outside the ESS to determine the amount of power available on the grid. The VIB ESS 100b can receive information about the amount of power consumed by the entire grid or a measured value of load usage outside the ESS to control charging or discharging of the VIB ESS 100b.

[0112] The load outside the ESS refers to a load for power usage outside the VIB ESS 100b and the charger 50, and refers to a load within the primary power domain 40b such as power usage within a building, a house, a server, a subway, etc.

[0113] Information about the grid maximum power amount can be input to the VIB ESS 100b in advance, and if the grid maximum power amount is changed, the VIB ESS 100b stores the changed value. The input value can be stored in the ESS 100b and maintained for a certain period of time. The VIB ESS 100b can store information about the grid maximum power amount (Grid_Max) in a format such as 380V AC / 150KW.

[0114] 10, a grid such as a power source 10 supplies power to an energy storage device 100b, a charger 50, and other loads (loads outside the ESS) other than the energy storage device and the charger. The energy storage device 100b may also include one or more power meters 205, 211, 212, and 220 that measure the amount of power of the grid, the energy storage device 100b, the charger 50, and other loads (loads outside the ESS).

[0115] The controller of the energy storage device 100b can determine whether to charge or discharge the energy storage module or supply power to a charger or other load using one or more of the amounts of power in the grid or the amounts of power in other loads measured by the power meters 205, 211, 212, and 220.

[0116] In an embodiment in which the amount of power in the grid can be determined from the amount of power in other loads (loads outside the ESS), the energy storage device 100b can use the value measured by the power meter 220 arranged in the load outside the ESS to determine whether to charge or discharge the energy storage module, or to supply power to a charger or other load.

[0117] On the other hand, when the amount of power in the grid cannot be confirmed from the amount of power in other loads, or when it is necessary to confirm the amount of power in the grid in real time without error, the energy storage device 100b can use the value measured by the power meter 205 arranged in the power source 10 to determine whether to charge or discharge the energy storage module, or to supply power to a charger or other load.

[0118] FIG. 11 is a diagram illustrating a process in which an ESS operates in response to an increase in power usage within a grid according to an embodiment of the present invention. The controller 150 stores the maximum amount of power available to the grid (Grid_Max) in step S321. This allows the power source 10 to provide information about the maximum amount of power available to the controller 150. Alternatively, the maximum amount of power available to the power source 10 can be input to the controller 150 in advance.

[0119] Thereafter, the power meter 220 measures the power usage (Primary_Usage) in the primary power domain, and the controller 150 calculates the expected usage within N hours (S322). The controller 150 can accumulate and store information on the power usage (Primary_Usage) in the primary power domain. The controller 150 monitors the power usage (Primary_Usage) in the primary power domain in real time, and if the power usage increases, calculates the expected usage within N hours.

[0120] At this time, the controller 150 may calculate the expected usage amount by taking seasonal factors into account. In one embodiment, the controller 150 may calculate the expected usage amount based on information about a time period (e.g., 2:00 PM to 4:00 PM) when the air conditioner is likely to be used in the corresponding space (e.g., building, house, etc.).

[0121] As a result, the controller 150 determines whether the current power usage (Primary_Usage) of the primary power domain is within a stable range or is below a reference value, but whether the expected usage within N hours will fall outside the stable range or exceed the reference value (S323). In this case, the controller 150 proceeds to a standby mode in which the power usage (Primary_Usage) of the primary power domain can be supplemented in preparation for an increase in power usage.

[0122] The controller 150 checks whether the charger 50 is in use (S324). If the charger 50 is in use, the controller 150 can control the charger 50 to proceed with charging using only grid power (S325). This is to preserve the power stored in the energy storage device 100 so that it can supplement the power usage in the primary power domain.

[0123] Also, if the charger 50 is not in use or if the charger 50 is charging using only grid power, the controller 150 measures the SOC of the energy storage device 100 (S326). If the measurement result shows that the SOC of the energy storage device 100 is equal to or lower than the reference value (S327), the controller 150 proceeds with charging the energy storage device 100 (S328).

[0124] When the process of FIG. 11 is applied, if the power usage (Primary_Usage) of the primary power domain increases, the energy storage device 100 can provide supplemental power. FIG. 12 is a diagram showing the configuration of an ESS according to another embodiment of the present invention. Externally supplied power is applied to a battery pack 110d via a ground fault device (GFD) 127d and a switch gear 125d. The detailed configuration of the switch gear 125d is shown in one example as a switched-mode power supply (SMPS) 121d and a pack BMS 120d. The pack BMS 120d can perform control and sensing, and can control LEDs and relays and sense current and voltage. In FIG. 12, the switch gear 125d and PMS 130d can form a controller 150.

[0125] FIG. 13 is a diagram showing the configuration of a charger according to one embodiment of the present invention. The charger control unit 550 controls the operation of the charger 50 and controls the various components 510 , 520 , 530 , and 540 that make up the charger 50 .

[0126] The interface unit 510 provides an interface for a user to input or check information during the charging of various devices such as an electric vehicle or an electric bicycle from the charger 50. The interface unit 510 may be configured with a touch screen, buttons, and the like.

[0127] The communication unit 520 transmits and receives information to and from an external device. The communication unit 520 can receive information about the currently available power status and whether the input power is input from the grid or the ESS from the ESS 100 or the PMS 130. The communication unit 520 can also transmit information about the current charging status of the charger 50 to the ESS 100 or the PMS 130. Alternatively, the communication unit 520 can transmit information about the current charging status to another charger.

[0128] The charging unit 530 charges other devices (electric vehicles, electric bicycles, electronic products, etc.) The power supply unit 540 receives power from an external source and provides it to the charging unit 530. The charger control unit 550 outputs the amount, time, options, etc. related to charging to the interface unit 510 according to the source of power supplied by the power supply unit 540. The charger control unit 550 can control the charging unit 530 according to the source of power supplied by the power supply unit 540, the charging options set by the interface unit 510, etc.

[0129] The charger control unit 550 determines the charging amount or the charging time according to the type of the power supply source. The charging unit 530 proceeds with charging according to the time or amount selected by the interface unit 510.

[0130] By utilizing some or all of the features of the present invention, a battery charging management system can be used to analyze the details of power usage generated during a user's charging process at an ESS or electric vehicle charging station, charge only for the amount of power actually charged, and analyze the power usage status and check power loss. According to an embodiment of the present invention, the battery charging management system can include means for understanding the details of use or consumption of power delivered from the ESS and analyzing information on energy usage and loss. Such power usage information analysis means can resolve issues related to the difference between the actual power used and the delivered power as well as the occurrence of abnormalities in the power delivered from the ESS.

[0131] In an ESS operation system, in order to perform various controls to supply power from the power grid to the ESS battery, various measurements, checks, supervision, and / or monitoring of the inside of the battery, the outside of the battery, the surrounding environment, and the entire system must be performed at each stage (level). According to at least one embodiment of the present invention, the monitoring levels include four levels. Each level is connected by a network communication line and has the function of exchanging signals and issuing or executing commands.

[0132] FIG. 14 is a conceptual diagram illustrating an example of the operational status management range when the monitoring levels are configured from level 1 to level 4, as an example in which some or all of the features of the present invention are applied to an ESS security management system.

[0133] According to at least one embodiment of the present invention, the monitoring levels may include one or more of Level 1 including a BMS directly connected to a battery, Level 2 including Level 1 and including a master BMS connected to aggregate the BMSs of Level 1, Level 3 including Level 2 and including a power management system (PMS) that controls one or more of heating / cooling, loads, and the grid, and Level 4 including Level 3 and including a top-level energy management system (EMS) that controls one or more of ESSs and power systems in various regions. When such monitoring levels are configured in four stages, the multiple levels can be specifically configured as follows:

[0134] In the ESS battery charging management system utilizing these four levels, battery charging management can be performed by including a power usage information collection unit that collects power usage information related to actual charging power and other power (e.g., heater power, BMS balancing power, V2L power, external outflow loss power, etc.), an information analysis unit that classifies or analyzes the information collected by the power usage information collection unit, and a charging execution unit that stops charging or controls the charging state based on the analysis results.

[0135] In addition, some or all of the features of the present invention can be applied to an electric energy supply method and system thereof. More specifically, the present invention relates to an electric energy supply method for efficiently supplying electric power to an electric energy storage or electric energy consumption area including an energy storage system (ESS) through a grid that receives electricity from a power supply source, and an electric energy supply device and supply system using the same.

[0136] In addition, when supplying power from the grid and ESS, information on power consumption and residual power can be collected and evaluated, and the charging and discharging of the ESS and the supply of electrical energy from the grid can be efficiently controlled and managed, which allows for the optimization of the grid's power amount, optimization and minimization of losses due to excess power and peak power, and suppression of grid overload.In addition, since the mutually complementary relationship between the grid and ESS can be maintained, high output is possible even when the grid's total power supply is insufficient or there is a momentary power outage or blackout, which has the advantage of enabling stable supply and demand of grid power.

[0137] FIG. 15 illustrates an example of a system that supplies power from a grid to an ESS and a power consumption area, controls information about available power acquired by the PMS of the ESS, and controls power supply to the power consumption area, and performs electrical energy supply including ESS charge / discharge management.

[0138] An electric energy supply system can be provided, which includes an ESS that receives power through a grid and performs charging and discharging, a charger that receives power from one or more power sources in the ESS or the grid, and auxiliary equipment that receives power from a load outside the ESS, and includes a step of storing the maximum output power that can be output from the grid; a step of measuring or receiving the amount of power used by the load outside the ESS of the auxiliary equipment; a step of measuring the amount of power used by the grid; and a step of controlling the charging or discharging of the ESS based on the power information collected at each of the above steps.

[0139] For example, while LIBs generate heat and affect battery life at high output, vanadium-ion batteries (VIB) are capable of stable high output. Also, while LIBs have limitations such as 1C charge and 1C discharge, vanadium-ion batteries (VIB) are capable of high output and input / output flow control. For example, in the event of a grid power outage, an ESS that uses a vanadium-ion battery (VIB) can provide high output support to both the grid and the charger, making ESS charge / discharge management particularly efficient when using a vanadium-ion battery (VIB).

[0140] In particular, since there is no risk of fire due to overload in the case of a vanadium ion battery (VIB), when such a vanadium ion battery (VIB) is applied to the ESS of the present invention, the electrical energy supply system of the present invention can be suitably applied while ensuring safety in various ancillary equipment, making it a very effective power supply system. Furthermore, since the present invention is capable of safe and efficient energy supply, it can be used as a very effective, safe, and environmentally friendly energy supply means for energy conservation, energy environment, and carbon neutrality.

[0141] Additionally, some or all of the features of the present invention may be utilized to implement high C-rate output and cell balancing control according to output.

[0142] Figure 16 shows various cell deviations for the cells in the battery inside the ESS when the ESS is charged and discharged at a high C-rate for a specific load. <1> , <2> and <3> FIG.

[0143] The inventors recognized the problem of increased cell deviation probability and deviation voltage during high C-rate charge / discharge. As a solution, the balancing current can be adjusted using pulse width modulation (PWM), and it can be controlled by methods such as balancing with maximum current amount at high C-rate and balancing with minimum current amount at low C-rate.

[0144] As a result, it is possible to maintain a stable high C-rate by dynamically controlling the balancing current. For example, if there are many cells with cell deviation, PWM control can be performed to balance more specifically the cells.

[0145] The specific balancing method can be applied in various ways and is not limited, but the fundamental importance is to adjust the balancing current flexibly. Also, the balancing current can be controlled by controlling the current through PWM control after lowering the resistance value of the balancing current limiting element as much as possible while still protecting the balancing switch element.

[0146] The inventors also recognized that if there are many cells that are over-discharged during high C-rate charge / discharge, there may be a concern that the cell monitoring BMS may stop operating. Similarly, with existing configurations or conventional technologies, stable operation was impossible when high-power discharge was performed while using battery power due to fluctuations in the BMS input power. In other words, when the BMS power supply is cut off, the ESS power is usually cut off, causing many difficulties during high-power discharge. In addition, when using an external power supply as with existing / conventional technologies, there are problems with the addition of parts such as numerous connector wires, the addition of the necessary manufacturing processes, and the overall increase in costs, resulting in an increase in unit price.

[0147] The solution is to configure a boost circuit so that the BMS can operate normally when only a minimum voltage is input. The battery voltage is input first, and then the input voltage is converted (boosted) to a voltage that the BMS can operate at, and then provided as the BMS power input.

[0148] As a result, the BMS can operate stably even when deviations in the battery occur, and even when multiple over-discharged batteries occur. Since only a few elements are added to the internal circuit board of the BMS, it can be implemented without adding any special processes and minimizing increases in unit costs.

[0149] The embodiments of the present invention have been described above. An embodiment of the present invention can also be described as follows. At least some embodiments present a power control system comprising: an energy storage device (ESS) connected to a power grid and having a battery; a power conversion device (PCS) operatively connected to the power grid and the energy storage device (ESS); and a control unit that provides control to execute charging and discharging procedures for the battery with priority given to power conversion efficiency of the power conversion device (PCS).

[0150] Because priority is given to the power conversion efficiency of the power conversion system (PCS), the battery has a higher efficiency than the power loss of the power conversion system (PCS), allowing stable operation regardless of the power output of the power conversion system (PCS).

[0151] In order to prioritize the power conversion efficiency of the power conversion system (PCS), the battery can be charged and standby at a voltage above a certain level for efficient discharge, and can be charged with an optimal amount of power according to the specifications of the power conversion system (PCS) for efficient charging.

[0152] Here, the voltage above a certain level can vary depending on the battery capacity, charging / discharging conditions, operation of the power control system, etc. For example, the certain level may be determined to be 0.5V and can be set based on related experiments, various measurements, and operational experience. The specific voltage of the certain level may change depending on the battery life, and the necessary certain voltage level can be changed with appropriate control depending on the situation.

[0153] The power control system is characterized in that the battery is a vanadium ion battery (VIB). The power control system is characterized by having an output between 0.2C and 1C, at which the vanadium ion battery (VIB) has the highest efficiency.

[0154] For the charging procedure, the control unit calculates the optimal amount of charging power for the battery, compares the calculated amount of power with the power grid surplus power, and if there is surplus power, performs control to confirm whether the amount of charging power for the battery matches the optimal efficiency range of the power conversion system (PCS).

[0155] The control unit selectively executes one of the following controls: setting the charging power based on the calculated amount of power; setting the charging power in the maximum efficiency range of the power conversion system (PCS); and setting the charging power in the minimum efficiency range of the power conversion system (PCS).

[0156] For the discharging procedure, the control unit performs discharging in a maximum efficiency section of the power converter (PCS) when the amount of power in the power grid is insufficient. The control unit executes the charging procedure when the battery voltage is not at an optimal discharge voltage when there is a power margin in the power grid.

[0157] The energy storage system (ESS) includes a charger for charging an electric vehicle, and the control unit adjusts charging and discharging of the energy storage system (ESS) according to a charging speed of the electric vehicle, and provides operation control to correspond to an optimal efficiency range for power conversion.

[0158] Additionally, at least some embodiments provide a method for controlling a power conversion device, which uses a power conversion device that controls the transfer of at least one of power from a power grid and power from an energy storage device (ESS) to an electric vehicle charging system and adjusts charging and discharging of the ESS according to an electric vehicle charging rate, thereby providing operational control to correspond to an optimal efficiency range for power conversion, and the power conversion device performs control to perform power conversion according to a specific charging and discharging range of the ESS to satisfy the optimal efficiency range of a power conversion system (PCS) connected to the ESS, taking into account power efficiency.

[0159] The energy storage device (ESS) uses a vanadium-ion battery (VIB), which has a wider charge / discharge rate (C-rate:C) range compared to lithium-based batteries. The vanadium-ion battery (VIB) can achieve the wide charge / discharge rate (C-rate) range because it does not have an irreversible reaction caused by the phase change of lithium from solid to ion.

[0160] The charging and discharging of the energy storage device (ESS) can be adjusted according to the electric vehicle charging speed, and operation control can be performed to correspond to the optimum efficiency section for power conversion, so that the discharging and charging of the energy storage device (ESS) can all be performed during the electric vehicle charging procedure.

[0161] Here, the execution of both discharging and charging may mean that they are performed simultaneously. However, this does not necessarily mean that charging and discharging are performed at the same time. In other words, it means that the ESS is both discharged and charged while the electric vehicle is being charged.

[0162] The specific charge / discharge range of the VIB ESS is determined according to the specifications of the PCS. The vanadium-ion battery has a wider charge / discharge rate (C-Rate) range than a lithium-ion battery (LIB), allowing the power conversion device to perform control to satisfy the optimum efficiency range of the PCS.

[0163] At least some embodiments provide a power conversion device operatively connected to a power grid and an energy storage device (ESS), comprising: a conversion unit that converts power from the power grid; and a control unit that controls transmission of power from the power grid to an electric vehicle charging system and adjusts charging and discharging of the energy storage device (ESS) in accordance with an electric vehicle charging rate, thereby providing operational control to correspond to an optimal efficiency range for power conversion.

[0164] Here, the optimum efficiency range can be determined according to the specifications of the PCS. For example, referring again to Figures 3(a) to 3(c), the optimum efficiency range of the corresponding PCS can be in the range of 50kW to 100kW or 100kW to 200kW. Furthermore, the efficiency of power conversion, which adjusts the charging and discharging of the ESS, can be considered as the basis for PCS control. Meanwhile, the efficiency of power conversion is the overall efficiency (round-trip efficiency) that takes into account both the charging and discharging operations, and it can be considered that the use of the power conversion technology of the present invention will improve the related overall efficiency.

[0165] The energy storage device (ESS) uses a vanadium-based battery, which has a wider charge / discharge rate (C-rate) range than a lithium-based battery. The vanadium-based battery can achieve the wide charge / discharge rate (C-rate) range because it does not undergo irreversible reactions caused by the phase change of lithium from solid to ion. The wide charge / discharge rate (C-rate) range is characterized by being 0.2 to 10C.

[0166] Here, the numerical range of the charge / discharge rate (C-Rate) varies depending on the capacity, control method, operating environment, etc. of the vanadium ion battery (VIB). That is, even if the C-Rate exceeds or slightly deviates from the above-mentioned 0.2 to 10C, more efficient operation than the existing lithium ion battery (LIB) is possible even when the charge / discharge regulation control according to the present invention is implemented.

[0167] At least some of the components and functions of the control unit are implemented in a power conversion system (PCS) of a battery management system (BMS), and at least some of the components and functions of the control unit are implemented in a power bank of the battery management system (BMS).

[0168] The operation control for adjusting the charging and discharging of the energy storage device (ESS) according to the charging speed of the electric vehicle and corresponding to the optimum efficiency section for power conversion is performed such that the discharging and charging of the energy storage device (ESS) are all performed during the electric vehicle charging procedure.

[0169] The electric vehicle charging procedure starts a fast charging section first and then enters a slow charging section, and in the fast charging section, the electric vehicle is charged using mainly power from the power grid but the energy storage system (ESS) is discharged to assist the power grid, and in the slow charging section, the energy storage system (ESS) is discharged and charged depending on the state of the power grid.

[0170] Here, fast charging and slow charging are relative concepts and vary depending on the power grid's power supply status and ESS discharge status. Electric vehicle charging can basically be divided into three levels. Level 1 can be considered slow charging (up to 16A) when using a standard outlet. Level 2 is charging using a 32A current, and is called slow charging in Korea when AC power is charged to the vehicle. Level 3 supplies DC of 400V or more, and is called quick charging in Korea. Therefore, this can be said to mean that the first half of electric vehicle charging is fast (quick) charging with a DC supply that is relatively high in power and fast, and the second half is slow (slow) charging with an AC supply that is relatively low in power and slow. Alternatively, whether charging is fast or slow can be determined using the charge / discharge rate (C-rate).

[0171] The operation control for adjusting the charging and discharging of the energy storage device (ESS) according to the charging speed of the electric vehicle to correspond to an optimal efficiency range for power conversion may include the steps of: the power grid has a maximum power amount; the energy storage device (ESS) and a charger connected to the power grid have a required power amount required for charging the electric vehicle; and, if the required power amount is greater than or equal to the maximum power amount, discharging the energy storage device (ESS) with power in a range exceeding the maximum power amount to charge the electric vehicle; and, if the required power amount is less than the maximum power amount, charging the energy storage device (ESS) with power in a range below the maximum power amount.

[0172] The energy storage device (ESS) is a power conversion device comprising: at least one secondary battery capable of being charged and discharged; an input unit that receives power from a power grid to charge the secondary battery; an output unit that discharges the secondary battery and provides power to a charger for charging an electric vehicle; and a controller operatively connected to the secondary battery, the input unit, and the output unit, and configured to maintain a state of charge (SoC) of the secondary battery at the start of charging the electric vehicle similar to a state of charge (SoC) of the secondary battery at the end of charging the electric vehicle.

[0173] Here, maintaining a similar state of charge (SoC) can be seen as a condition that is met if the relative levels at the start and end of charging are within a specific range. For example, if the SoC levels at the start and end of charging are within 15% of each other, this can be seen as a similarly maintained state. The percentage (%) or specific numerical range of the relevant range can vary depending on the operation of the energy storage device (ESS).

[0174] Also, at least some embodiments provide a power conversion device efficiency control system including: a VIB ESS (Vanadium-ion Battery Energy Storage System); a power conversion system (PCS) connected to a power grid and the VIB ESS; and a power conversion device operatively connected to the PCS, wherein the power conversion device performs control to perform power conversion according to a specific charge / discharge range of the VIB ESS so as to satisfy an optimal efficiency range of the PCS in consideration of power efficiency.

[0175] The specific charge / discharge range of the VIB ESS is determined according to the specifications of the PCS. Because the vanadium-ion battery has a wider charge / discharge rate (C-Rate) range than a lithium-ion battery (LIB), the power converter can perform control to satisfy the optimal efficiency range of the PCS. When the optimal efficiency range of the PCS is in the range of 50kW to 200kW, the power converter performs control so that the VIB ESS is charged or discharged in the range of 50A to 200A.

[0176] Although all components constituting an embodiment of the invention are described as being combined together or operating in combination, the present invention is not necessarily limited to such an embodiment, and all components may be selectively combined together and operate in one or more units within the scope of the present invention.

[0177] Furthermore, all of the components can be implemented as independent pieces of hardware, or some or all of the components can be selectively combined to implement a computer program having program modules that perform some or all of the combined functions in one or more pieces of hardware. The codes and code segments that make up the computer program can be easily construed by those skilled in the art. Such a computer program can be stored in a computer-readable storage medium and read and executed by a computer to implement embodiments of the present invention. Storage media for computer programs include storage media such as magnetic recording media, optical recording media, and semiconductor recording devices. Furthermore, a computer program that implements embodiments of the present invention includes a program module that is transmitted in real time via an external device.

[0178] The above-described embodiments should be understood to be illustrative in all respects and not restrictive, and the scope of the present invention will be indicated by the following claims rather than the above detailed description. The meaning and scope of the claims should be interpreted as including all changes and modifications derived from the equivalent concepts.

Claims

1. Energy storage systems (ESS) connected to the power grid and equipped with batteries; Power converters (PCS) operationally connected to the power grid and the energy storage system (ESS); and A power control system characterized by including a control unit that provides control to execute charging and discharging procedures for the battery, prioritizing the power conversion efficiency of the power conversion device (PCS).

2. In the power control system according to claim 1, in order to prioritize the power conversion efficiency of the power converter (PCS), the battery is, A power control system characterized by having a higher efficiency than the power loss of the aforementioned power converter (PCS), and being designed to operate stably regardless of the output of the power converter (PCS).

3. In the power control system according to claim 1, in order to prioritize the power conversion efficiency of the power converter (PCS), the battery is, A power control system characterized by being able to charge and stand by at a voltage above a certain level for efficient discharge, and being able to charge with the optimal amount of power according to the specifications of the power conversion device (PCS) for efficient charging.

4. A power control system according to claim 1, characterized in that the battery is a vanadium-ion battery (VIB).

5. A power control system according to claim 4, characterized in that the vanadium ion battery (VIB) has an output between 0.2C and 1C, which is the most efficient range for the vanadium ion battery.

6. A power control system according to claim 1, wherein the control unit calculates the optimal amount of power to charge the battery for the charging procedure, compares the calculated amount of power with the surplus power of the power grid, and, if there is surplus power, performs control to confirm whether the amount of power to charge the battery matches the optimal efficiency interval of the power converter (PCS).

7. In the power control system according to claim 6, the control unit is: A power control system characterized by selectively executing one of the following: a control that sets the charging power using the calculated amount of energy; a control that sets the charging power in the maximum efficiency section of the power converter (PCS); and a control that sets the charging power in the minimum efficiency section of the power converter (PCS).

8. In the power control system according to claim 1, the control unit shall, for the discharge procedure, A power control system characterized in that, when the amount of power in the power grid is insufficient, discharge proceeds in the maximum efficiency section of the power converter (PCS).

9. A power control system according to claim 8, characterized in that the control unit executes the charging procedure when there is sufficient power in the power grid and the battery voltage is not at the optimal discharge voltage.

10. A power control system according to claim 1, wherein the energy storage device (ESS) includes a charger for charging an electric vehicle, and the control unit adjusts the charging and discharging of the energy storage device (ESS) in accordance with the charging speed of the electric vehicle to provide operational control to correspond to the optimal efficiency interval for power conversion.

11. Energy storage devices containing vanadium-ion batteries (VIBESS); Power grids and power conversion systems (PCS) connected to the VIB ESS; and Includes a power converter that is operationally connected to the PCS, The power converter is controlled to perform power conversion according to a specific charge / discharge range of the VIB ESS, taking power efficiency into consideration, so as to satisfy the optimal efficiency interval of the PCS.

12. A power converter efficiency control system according to claim 11, characterized in that the specific charge / discharge range of the VIB ESS is determined according to the specifications of the PCS.

13. A power converter efficiency control system according to claim 11, characterized in that the vanadium-ion battery has a wider charge / discharge rate (C-Rate) range compared to a lithium-ion battery (LIB), enabling the power converter to perform control to satisfy the optimal efficiency interval of the PCS.

14. A power converter efficiency control system according to claim 11, characterized in that when the optimal efficiency interval of the PCS is in the range of 50 kW to 200 kW, the power converter performs control so that the VIB ESS is charged or discharged in the range of 50 A to 200 A.

15. Using a power converter that provides control for transmitting at least one of the power from the power grid and the power from an energy storage system (ESS) to an electric vehicle charging system, and operational control for adjusting the charging and discharging of the ESS in accordance with the electric vehicle charging speed to correspond to the optimal efficiency interval for power conversion, A control method for a power converter, characterized in that the power converter performs control so that power conversion is carried out according to a specific charge / discharge range of the ESS, taking power efficiency into consideration and satisfying the optimal efficiency interval of the power conversion system (PCS) connected to the ESS.

16. A method for controlling a power conversion device according to claim 15, characterized in that the energy storage device (ESS) is a vanadium-ion battery (VIB) with a wider charge / discharge rate (C-rate:C) range compared to a lithium-based battery.

17. A control method for a power converter according to claim 15, characterized in that the charging and discharging of the energy storage device (ESS) is adjusted in accordance with the electric vehicle charging speed, and operational control is performed to correspond to the optimal efficiency interval for power conversion, so that the discharging and charging of the energy storage device (ESS) can be fully performed during the electric vehicle charging procedure.

18. A method for controlling a power converter according to claim 16, characterized in that the specific charge / discharge range of the VIB ESS is determined according to the specifications of the PCS.

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