Method for charging power storage unit including capacitor secondary battery

Abstract

To provide a charging method capable of sufficiently exhibiting each power storage capacity even if there is difference in power storage capacity of a power storage unit on the premise that a capacitor is used as a power storage element and there are variations in the power storage elements constituting the power storage unit and a combination thereof.SOLUTION: A charging method of a power storage unit is configured by connecting a power storage element group composed of capacitors in series, parallel, or series-parallel. After a voltage between terminals of constituting power storage element groups of the power storage unit is measured, and after a known charge Q is supplied to all the power storage element groups, a voltage between terminals of each power storage element group is measured, the power storage element group having the largest voltage change amount is specified, a charge amount until the power storage element group having the lowest power storage capability is fully charged is calculated, and after the power storage unit is charged up to the charge amount, charging operation is completed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charging method for a charging system using a storage element. [Background technology]

[0002] Rechargeable energy storage devices such as lithium-ion batteries have rapidly spread in recent years and are used in a variety of fields, including mobile phones, laptops, electric vehicles (EVs), and electrically assisted bicycles.They have become indispensable devices in our daily lives and social lives.

[0003] In the future, developments in various forms of mobility, including not only ground transportation but also air transportation, are expected. Furthermore, as a countermeasure against global warming caused by carbon dioxide emissions, there is a growing need for energy storage devices to stabilize the power supply by charging electricity from renewable energy sources such as solar and wind power when there is a surplus and discharging it when there is a shortage. Furthermore, to expand the applications of energy storage devices to various robots for improving quality of life (QOL) so that people can lead comfortable daily lives while preparing for the rapid aging and population decline of the future, as well as humanoid robots for nursing care, patrols, and various assistance, and for factory automation and production line integration, energy storage elements and energy storage units using them must be further miniaturized and have high capacity, while also being capable of rapid, high-current charging and discharging, having a long lifespan, and being easy to handle. As a result, it is clear that energy storage devices will be used in an even wider range of fields than before. Based on these ideas, various configurations have been proposed for charging equipment for the above-mentioned EV storage elements to enable faster charging and discharging than ever before (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-058051 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned energy storage unit is generally composed of a group of energy storage elements in which a combination of a plurality of energy storage elements connected in series, parallel, or series-parallel is further connected in series, parallel, or series-parallel as required, and the energy storage device is composed of the energy storage units further connected in series, parallel, or series-parallel as required.

[0006] The energy storage elements currently in practical use, mainly secondary batteries, have two major problems: first, problems related to charging and discharging, mainly due to variations in the storage capacity, internal resistance, leakage current, allowable output current, etc. of each energy storage element; and second, restrictions on handling the energy storage elements during actual use, such as the operating temperature range, output response time, number of charge / discharge cycles and lifespan, deterioration of element characteristics, and restrictions on maximum and minimum voltage during use.

[0007] The first problem here is that it is highly unlikely that the individual energy storage elements, which are the smallest units that make up an energy storage unit, will all have the same values ​​for output voltage, allowable energy storage capacity, etc. This is because the energy storage capacity of individual energy storage elements generally varies within a certain range, and the distribution of this variation is the cumulative effect of variations in the materials and components that make up the energy storage elements, as well as differences in the environment of each manufacturing process, the equipment groups, the manufacturing line, etc., resulting in slightly different characteristics for each energy storage unit. For this reason, it is quite difficult to reduce the deviation in the chargeable energy storage capacity and output voltage values ​​of the energy storage unit and the energy storage elements of each component as a finished product.

[0008] Therefore, the current situation is that the finished energy storage element products are usually measured to measure variations, divided into multiple groups so that they fall within a preset range, and then combined to reduce deviations in variations, resulting in extra effort and man-hours to keep the mutual variations within a group of energy storage elements connected in series or series-parallel within a preset range.As a result, there are problems in that it is not possible to improve the production efficiency of energy storage units and it is difficult to reduce costs.

[0009] In addition to the enormous effort required to eliminate variations in the finished product, there is also the fundamental problem of how difficult it is to predict phenomena such as aging and deterioration that occur depending on the type and specifications of the storage element.

[0010] Next, the second problem is that most of the energy storage elements currently in widespread use are rechargeable secondary batteries, and all of these secondary batteries use chemical reactions.

[0011] Therefore, (1) there are upper and lower limits to the operating temperature range; if the temperature is too high, the reaction will proceed too quickly and cause damage due to heat generation, and if the temperature is too low, the reaction will not proceed and the battery will not function; (2) because electricity is generated by a chemical reaction, there is a limit to the response time, making it difficult to respond to sudden increases and decreases in current; (3) because unnecessary products are produced during the chemical reaction, repeated charging and discharging will gradually deteriorate the performance, so there is a limit to the number of times it can be charged and discharged; (4) there is a lower limit to the battery's output voltage, and if the voltage drops below this, the battery will no longer function as a battery, in other words, it will lose its function; therefore, it is an energy storage element that has inherent problems such as the need for regular inspections and charging when necessary.

[0012] Furthermore, the performance of secondary batteries gradually deteriorates with repeated charging and discharging, but it is difficult to predict the extent of this deterioration. As batteries are used, the characteristics of each storage element deteriorate and the deviation between them also increases. Considering the future expansion of storage elements into various fields, current secondary batteries still have problems that need to be solved, but are difficult to solve.

[0013] The object of the present invention is to provide a method for charging a storage unit consisting of a capacitor secondary battery, which uses a large-capacity capacitor (hereinafter referred to as a capacitor), now exceeding tens of thousands of fara, as a storage element to provide a function similar to that of a secondary battery (hereinafter referred to as a capacitor secondary battery), and which, assuming that there is individual variation among the storage elements that constitute the storage unit and among storage element groups formed by combining these, makes it possible to fully utilize the storage capacity of each storage unit even if there are individual differences in the storage capacity of the storage unit and among the storage elements.

[0014] The charging method of the present invention can also be applied to conventional charging methods for secondary batteries. [Means for solving the problem]

[0015] In order to solve the above-mentioned problems, the present invention proposes a new charging method that treats large-capacity capacitors (hereinafter referred to as capacitors), which have emerged with capacities exceeding tens of thousands of far-field, as storage elements with functions equivalent to secondary batteries (hereinafter referred to as capacitor-secondary batteries), and allows for variations in the various characteristics of so-called storage elements, including capacitors and conventional secondary batteries.

[0016] The method for charging a power storage unit comprising a capacitor secondary battery according to claim 1 of the present invention comprises: A method for charging a storage unit comprising a capacitor secondary battery configured by connecting a single storage element comprising a capacitor, or a group of multiple storage elements connected in parallel, or m sets (m is a natural number) of storage elements further connected in series, parallel, or series-parallel, Step S1 of measuring the inter-terminal voltages of each of the first to n-th (n is a natural number of 2 or more) energy storage element groups constituting the energy storage unit; a step S2 of accumulating a charge δQ for each of the storage element groups by flowing a preset charge δQ through the first to n-th storage element groups connected in series in order to identify the storage element group having the smallest storage capacity among the storage element groups; Step S3 of measuring the terminal voltage of each storage element group after the charge ΔQ is applied to each storage element group in accordance with step S2; Step S4: calculating, for each storage element group, the amount of change between the terminal voltage measured in step S3 when the charge capacity is specified and the terminal voltage measured in step S1; In step S4, the terminal voltage of each storage element group is calculated to identify the storage element group with the largest change, i.e., the storage element group with the lowest storage capacity. If it is determined that the storage element group with the lowest storage capacity cannot be identified under the conditions at this time and the number of times steps S2 to S5 are repeated is less than a preset value, step S5 stores the terminal voltage information of the storage element group, adds 1 to the number of times it is repeated, and then returns to step S2, and if the number of times it is repeated exceeds a predetermined number, it performs a process of terminating the charging operation according to this procedure. Step S6: estimating and calculating the amount of charge required for the storage element group with the lowest storage capacity to be fully charged based on the information specifying the storage element group with the lowest storage capacity; The method is characterized by having step S7 in which the amount of charge calculated in step S6 is applied to the power storage unit, and when this is completed, the charging operation of the power storage unit is completed.

[0017] Furthermore, the method for charging a storage unit made of a capacitor secondary battery according to claim 2 of the present invention is as follows: A charging method for fully charging a group of storage elements that have not yet reached full charge after charging a storage unit made of a capacitor secondary battery, or for fully charging a group of storage elements by using this claim alone, and for specifying a specific group of storage elements and a charging order when charging, First, at the start of charging, each group of storage elements constituting the storage unit follows instructions from a higher-level device, etc., and if there is an instruction as to whether or not individual charging is required, that is accepted; if there is no instruction, all groups of storage elements are treated as having been designated; if there is a designation for charging, the designation is followed (in order of lowest inter-terminal voltage, ascending order of numbers, etc.); if there is no designation, the storage elements that require charging are charged in accordance with that designation; and in step S10, the storage element group to be charged first is selected in accordance with the instructions, and a switch for charging and a switch for measuring the inter-terminal voltage are operated. In accordance with the above-mentioned instructions, first, the switches for charging the storage element group and measuring the terminal voltage are closed, and charging is continued until the storage element group is fully charged. When it is determined that the storage element group is fully charged, the switches for detecting the voltage and for charging are opened. In step S11, Step S12: storing the fact that charging of the storage element group selected in step S11 has been completed; Based on the record of step S12, it is determined whether charging of all the designated groups of storage elements has been completed, and if it is determined that charging of all the designated groups of storage elements has been completed, the charging operation is completed; if not, the next group of storage elements to be charged is selected from the groups of storage elements that have not yet been charged, and after specifying the switches required for the new charging process, the process returns to step S11 and repeats steps S11 to S13.

[0018] Furthermore, the method for charging a storage unit made of a capacitor secondary battery according to claim 3 of the present invention is as follows: A charging method that can fully charge a group of storage elements that have not yet reached full charge or a group of storage elements that meet specific conditions in charging a capacitor secondary battery, When there is an instruction from the energy storage unit control unit, first, a step S20 of operating a group of switches for measuring terminal voltages of each energy storage element group constituting the energy storage unit to measure the voltages between the terminals, and recording information on the energy storage element numbers in ascending order of the terminal voltages; Step S21: according to charge necessity information and charge order instruction information of the storage element groups instructed by the storage unit control unit as necessary, and when instructed, according to the voltage information and charge necessity information of the storage element groups arranged in ascending order of inter-terminal voltage recorded in step S20, designate the storage element group to be charged first; Step S22: Close the contacts of the switches required to charge the storage element group designated in step S21 while measuring the terminal voltage of the storage element group, start the charging operation, and continue measuring the terminal voltage until the storage element group is fully charged. After the storage element group is fully charged, open all the contacts of the switches to complete charging of the storage element group. At this point, it is determined whether charging of all the designated storage element groups has been completed, and if charging has been completed, the contacts of all switches are opened and the charging operation is terminated, and if charging of the designated storage element groups has not yet been completed, the next storage element group to be charged is designated according to the instruction from among the designated storage element groups, and then the process is characterized by further including step S23, which returns to the beginning of step S22.

[0019] Furthermore, the method for charging the power storage unit according to claim 4 of the present invention comprises: The present invention is characterized in that each of the storage elements constituting the storage element group is made up of a chemical secondary battery instead of a capacitor. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a method for charging a storage unit consisting of a capacitor secondary battery that can fully utilize the storage capacity of each storage unit, even if there are individual differences in the storage capacity of the storage unit due to variations in the storage elements that are components of the storage unit and in the storage element groups that combine them. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is an explanatory diagram showing a schematic configuration of an electricity storage unit according to an embodiment of the present invention; [Figure 2] 3 is a flowchart illustrating a basic charging method for the power storage unit according to the embodiment of the present invention shown in FIG. 1. FIG. [Figure 3] 3 is a flowchart illustrating supplementary charging, part 1, for individually charging each of the energy storage element groups constituting the energy storage unit, following FIG. 2. FIG. [Figure 4] 4 is a flowchart illustrating a second supplementary charging method for individually charging some or all of the groups of energy storage elements constituting an energy storage unit, following the flowchart shown in FIG. 3 and continuing from FIG. [Figure 5] FIG. 5(a) is a characteristic diagram showing the relationship between the voltage and the charge amount of each storage element group constituting the storage unit when the storage element of the present invention is a capacitor, and FIG. 5(b) is a characteristic diagram showing the relationship between the voltage and the charge amount of each storage element group constituting the storage unit when the storage element of the present invention is a storage element consisting of a secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0022] A method for charging a power storage unit comprising a capacitor secondary battery according to one embodiment of the present invention will be described below with reference to the drawings. The power storage unit according to this embodiment (hereinafter simply referred to as the "power storage unit") uses a large-capacity capacitor as the power storage element. However, in the following description, in order to standardize terminology, facilitate understanding of the description, and emphasize the advantages of the present invention, the term "capacitor" will be used consistently rather than the term "capacitor." Furthermore, the term "power storage element group" will generally be used, but the term "capacitor group" will also be used in some cases. The power storage unit may also be referred to as a "capacitor power storage unit."

[0023] FIG. 1 is an explanatory diagram showing a schematic configuration of an energy storage unit according to one embodiment of the present invention. As is clear from FIG. 1, this energy storage unit includes a plurality of capacitor groups, each of which is formed by connecting capacitors, which are energy storage elements, in parallel, and these capacitor groups are connected in series. More specifically, as shown at the top of the drawing, a first capacitor group C1 includes capacitors C1-1, C1-2, C1-3, ..., C1-a (where a is a natural number of 2 or greater and may be different for each stage), each of which is connected in parallel. Note that although a is a natural number of 2 or greater, the effects of the present invention can be achieved even if a = 1 in some cases, and therefore this is within the scope of the present invention.

[0024] Similarly, the second capacitor group C2 includes capacitors C2-1, C2-2, C2-3, . . . C2-b (b is a natural number of 2 or more) connected in parallel.

[0025] Similarly, as shown at the bottom of this drawing, an nth (n is a natural number of 2 or more) capacitor group Cn is provided, which is configured by connecting capacitors Cn-1, Cn-2, Cn-3, ... Cn-x (x is a natural number of 2 or more) in parallel. The first to nth capacitor groups are connected in series to configure a capacitor unit (energy storage unit) 100.

[0026] In addition, there are variations among the storage elements that are components of the storage unit 100 and among the storage element groups that combine them, which means that there are individual differences in the storage capacity of the storage unit, as explained in the section on problems to be solved by the invention above.

[0027] In addition to the above, the power storage unit 100 also includes a collective charging power supply unit 210, an individual charging power supply unit 220, and a voltage detection unit 250. Furthermore, switches SWU, SWC, and SWD that open and close the circuit are provided at appropriate locations in the circuit, and a switch switching control unit 260 that controls the opening and closing (connection / disconnection, or on / off) of each of these switches. Here, SWU-1 and SWU-2 are referred to as SWU, SWD-1 and SWD-2 as SWD, SWD(y-1) and SWD(y-2) as SWD(y), and SWC(x-1) and SWC(x-2) as SWC(x), where x and y are natural numbers. In addition, the power storage unit 100 also includes a control unit that controls all of these, i.e., a power storage unit control unit 200, for charging the power storage unit 100 using a charging method specific to the present invention. The power storage unit control section 200 includes a switch changeover control section 260 and also has a charge mode selection section 270 for selecting the optimum charge mode for the charging method specific to the present invention.

[0028] Depending on the form of the power storage unit 100, for example, when the power storage unit 100 is to be used in a vehicle or the like and a fairly large amount of power needs to be supplied, a collective charging power supply unit 210 and an individual charging power supply unit 220 may be provided in addition to the above, separately from the power storage unit 100. On the other hand, for example, when the power storage unit 100 is to be used in a home appliance or the like and a very large amount of power does not need to be supplied, all of the above-mentioned components may be integrated into the power storage unit 100.

[0029] That is, the above-mentioned collective charging power supply unit 210, individual charging power supply unit 220, voltage detection unit 250, switch switching control unit 260, and storage unit control unit 200 as a control unit for these may be provided in the storage unit 100 itself on a case-by-case basis depending on the type of application of the storage unit 100, or may be configured as separate entities.

[0030] The switch SW is made up of a plurality of switches. Specifically, the switches SWU (SWU-1, SWU-2) are for charging the entire power storage unit 100 by using the current from the collective charging power supply unit 210, and switches SWC(z) (where z is an integer from 1 to n) for switching the charging target in order to individually flow the current from the individual charging power supply unit 220 into only the terminal group of each power storage terminal group Cz selected from the power storage element groups C1-1 to C1-a, C2-1 to C2-b, C3-1 to C3-c, ..., Cn-1 to Cn-x. , Cn-1, Cn-x (hereinafter referred to as Cn) are connected in series, and switches SWD (SWD-1 and SWD-2) are used to measure the voltage across the capacitor groups C1, C2, C3, ..., Cn-1, Cn-x (hereinafter referred to as Cn), or switches SWD(y) (i.e., SWD(y-1) and SWD(y-2)) are used to select one storage element Cy (where y is an integer from 1 to n) from among the storage element groups C1, C2, C3, ..., Cn-1, Cn and measure the voltage across the terminals of the storage element group Cy with voltage detection unit 250.

[0031] The circuits opened and closed by switches SWD and SWD(y) have a larger input resistance than circuits opened and closed by other switches, and consideration is given to reducing the impact even during charging, etc., so that switches SWD can perform their original role of measuring voltage.

[0032] The switch SWU functions as a switch for collectively flowing current from the collective charging power supply unit 210 to the respective storage element groups C1, C2, C3, ..., Cn-1, and Cn that constitute the energy storage unit 100 when the respective storage element groups are connected in series, and as already explained, is composed of SWU-1 and SWU-2. By closing (connecting) the switches SWU and SWD and opening (disconnecting) all the other switches (SWC(x) and SWD(x)), it is possible to charge the respective storage element groups with the collective charging power supply unit 210 while also measuring the voltage between their terminals. In other words, by flowing current from the collective charging power supply unit 210 in this state, it is possible to charge the respective storage element groups C1, C2, C3, ..., Cn-1, and Cn at once, and also to measure the voltage between their terminals.

[0033] Furthermore, the group of storage elements C1 is provided with a switch SWC(1), i.e., SWC(1-1) and SWC(1-2), for flowing current only into this group of storage elements C-1 from the individual charging power supply unit 220. Similarly, the group of storage elements C2 is provided with a switch SWC(2) for flowing current only into this group of storage elements from the individual charging power supply unit 220, and the group of storage elements C3 is provided with a switch SWC(3) for flowing current only into this group of storage elements from the individual charging power supply unit 220.

[0034] Similarly, the group of storage elements Cn is provided with a switch SWC(n) that flows current only into this group of storage elements. In this way, each group of storage elements Cx (x is an integer from 1 to n) is provided with a pair of switches SWC(x), i.e., SWC(x-1) and SWC(x-2), that flows current between the terminals of the group of storage elements selected from the individual charging power supply unit 220.

[0035] Furthermore, each energy storage element group Cx (x is an integer from 1 to n, and the same applies below) is provided with a connection switch SWC(x) for connecting the energy storage element group Cx to the individual charging power supply unit 220 for charging, as well as connection switches SWD(x), i.e., SWD(x-1) and SWD(x-2), for connecting the terminal-to-terminal voltage of the same energy storage element group Cx to the voltage detection unit 250 to measure the terminal-to-terminal voltage. Opening and closing control of these switches is performed by a switch switching control unit 260 in the energy storage unit control unit 200.

[0036] Then, by closing (conducting) the switch SWC(x) corresponding to each storage element group Cx to charge the storage element group Cx using the individual charging power supply unit 220, and closing (conducting) the voltage detection switch SWD(x) and opening (blocking) the switches other than SWC(x) and SWD(x), it is possible to charge only the storage element group Cx by passing current from the individual charging power supply 220 while also measuring the voltage between the terminals.

[0037] Furthermore, the storage unit control unit 200 closes (connects) only the switches SWU, i.e., SWU-1 and SWU-2, and the switches SWD, i.e., SWD-1 and SWD-2, via the switch switching control unit 260, thereby charging the group of storage elements connected in series from the batch charging power supply unit 210 via the switches SWU, while connecting the terminal-to-terminal voltage of the group of storage elements connected in series to the voltage detection unit 250, thereby enabling the terminal-to-terminal voltage when the group of storage elements is connected in series.

[0038] More specifically, the switch SWD used when measuring the voltage when the storage element group is connected in series is composed of SWD-1 and SWD-2 as explained previously, and the switch SWD(x) used when measuring the voltage of the storage element group Cx individually is composed of n pairs of SWD(x-1) and SWD(x-2) (where x is a natural number from 1 to n) as explained previously.

[0039] When measuring the voltage of the storage element group Cx, the switch SWD(x), i.e., the two switches SWD(x-1) and SWD(x-2), are closed to connect both ends of the switch, and all other switches used for voltage detection, i.e., SWD(y) (where y is an integer from 1 to n other than x), are opened (cut off), thereby making it possible to measure the voltage value of the storage element group Cx using the voltage detection unit 250 of the storage unit control unit 200 when necessary.

[0040] Furthermore, when measuring the voltage with all the storage element groups connected in series, the switches SWD, i.e., SWD-1 and SWD-2, are closed to conduct electricity across both ends of the switch and connect it to the voltage detection unit 250, and the other switch SWD(x) (x is an integer from 1 to n) used for voltage detection is opened (cut off), so that the voltage between the terminals of the storage element groups C1 to Cn connected in series can be measured using the voltage detection unit 250.

[0041] As described above, by appropriately selecting the open (disconnected) or closed (conductive) states of the multiple switches SWU, SWD, SWC(x), and SWD(x) (x is an integer from 1 to n), when charging the selected group of storage elements Cx using the individual charging power supply unit 220, switches SWC(x) and SWD(x) are closed and all other switches are opened in order to simultaneously charge and measure the voltage between the terminals, and when charging the group of storage elements connected in series using the collective charging power supply unit 210, switches SWU and SWD are closed and all other switches are opened (released) in order to simultaneously charge the group of storage elements connected in series and measure the voltage, thereby enabling the selected group of storage elements to be charged while the voltage value is accurately measured by the voltage detection unit 250.

[0042] Next, a specific description will be given of the basic charging method for the energy storage unit according to the present invention shown in Fig. 1. First, it should be noted that the charging method for the energy storage unit made up of a capacitor secondary battery according to the present invention described below has the advantage that, even if there are variations in characteristics and aging among the energy storage element groups (capacitor groups) in which the energy storage elements (capacitors in this embodiment) of the present invention are connected in parallel, by knowing in advance the amount of charge that can be stored in each energy storage element group, the energy storage unit can be charged without overcharging even the energy storage element group with the smallest storage capacity in the energy storage unit.

[0043] Fig. 2 is a flow chart for explaining a basic charging method for a power storage unit according to one embodiment of the present invention. Note that, as shown in Fig. 1, the power storage element is a capacitor, and the power storage element group is a capacitor unit, but in the following explanation, these terms will be referred to as "power storage element" and "power storage element group," respectively. Charging the power storage unit is specifically carried out in the following procedure.

[0044] First, the terminal voltage of each of the energy storage element groups constituting the energy storage unit is measured (step S1). More specifically, at the start of a routine relating to the basic charging method for the energy storage unit, of the switches shown in Fig. 1, only switch SWD(1) (i.e., SWD(1-1) and switch SWD(1-2)) is closed (conductive state), and the other switches (SWD, SWU, SWC(x), SWD(x) (x is an integer from 2 to n) are all opened (cut off), and the terminal voltage V1 of the energy storage element group C1 is measured by voltage detection unit 250.

[0045] Next, switch SWD(1) is opened and switch SWD(2) is closed, and voltage detection unit 250 measures voltage V2 across terminals of power storage element group C2.

[0046] In this way, the voltages of the storage element groups at that time are measured up to the storage element group Cn. Note that the order in which the voltages of the storage element groups are measured does not have to be the order from storage element group C1 to Cn as described above, and may be measured in any order.

[0047] Next, in order to estimate the storage capacity of each storage element group and identify the storage element group with the smallest storage capacity, a charge of ΔQ is flowed between both electrodes of a storage module made up of storage element groups connected in series, thereby increasing the charge by ΔQ in each of the storage element groups C1 to Cn (step S2).

[0048] Then, after the charge δQ is applied to each storage element group in the above-mentioned step S2, the terminal voltages of all storage element groups constituting the energy storage unit are measured again. In this voltage measurement, the terminal voltages of each storage element group after the charge δQ is applied to each storage element group are measured using a measurement method similar to that used in the measurement in the above-mentioned step S1, and the values ​​are recorded in a storage element (memory not shown) provided in the energy storage unit control unit 200 (step S3).

[0049] At this time, the combination of opening and closing the above-mentioned switches for measuring the voltage of each storage element group is controlled by the switch switching control section 260.

[0050] Specifically, the energy storage unit control unit 200 calculates the change ΔV1, ΔV2, ΔV3, ... ΔVn (n is a natural number greater than or equal to 2) from the terminal voltage measured at the time of identifying the charge capacity in step S3 to the terminal voltage (before charge is applied) measured in step S1 for each energy storage element group (step S4).

[0051] Then, the storage element group with the smallest storage capacity (largest voltage change) is identified based on the fluctuation in the terminal voltage of each storage element. If it is determined that the voltage fluctuation value is too small to perform the above, or that there is still insufficient information because multiple pieces of information are required to make the determination, the following process is performed. Specifically, if the number of times δQ is given is within a preset upper limit, 1 is added to the number of times it is given and the process returns to step S2. If the number of times δQ is given exceeds the preset upper limit, this process is completed. Note that since this is abnormal processing, displaying the fact that the numerical limit has been exceeded or recording information is optional (step S5).

[0052] Here, the amount of change in the terminal voltage of each storage element group in this embodiment is a linear function of the voltage of the parallel-connected storage element groups and the amount of charge possessed by each storage element group, as shown in the characteristic diagram of Figure 5(a).

[0053] In other words, when the storage element is a capacitor, the relationship Q = C·V holds for the charge Q, the increased terminal voltage V, and the capacitance C of the connected storage element group. Therefore, the capacity and charge or power that can be charged for each storage element group connected in parallel can be easily calculated. In addition, the maximum and minimum capacitances of each storage element group can also be easily calculated. As a result, the allowable charge capacity of the entire energy storage unit can also be calculated.

[0054] Next, to calculate the amount of charge required to fully charge the storage element group with the smallest storage capacity, the amount of charge to be sought is found by ΔQ × Vx ÷ ΔVi using the difference Vx between the maximum applied voltage of the capacitors constituting the storage element group and the maximum inter-terminal voltage of each storage element group measured in step S4, and the voltage change value ΔVi of the storage element group with the smallest capacity (this value is also the largest value among the storage element groups), and this is calculated by the storage unit control unit 200. Note that the amount of charge is found by the product of the current value and the current flow time, so once the required amount of charge and the current value to be flowed are determined, the current flow time can be found by the required amount of charge ÷ current value (unit: seconds) (step S6).

[0055] Next, the charge calculated in the previous section is applied between the power supply terminals of the storage module, which is made up of a group of storage elements connected in series. The previously calculated charge, δQ × Vx ÷ ΔVi = Qmin, is applied to the group of storage elements connected in series that make up the storage unit. Since charge is the time integral of current, if the current is constant, current is applied for a time calculated by Qmin ÷ current (A), or if the current fluctuates, until the time integral of the current reaches Qmin. In this way, the basic charging shown in Figure 2 is completed via step S7. Once the charge has been applied to the storage module, charging is complete (step S7). In this way, the routine related to basic charging ends.

[0056] Next, a first supplementary charging method will be described in which, after the charging of the power storage unit is completed by steps S1 to S7 described above, the power storage elements constituting the power storage unit are individually charged to fully charge each power storage unit.

[0057] The reason why this supplemental charging method for the energy storage unit is introduced in this invention is as follows: Even when an energy storage element is generally fully charged, the charge stored therein gradually decreases over time due to self-discharge and leakage current, and the value of this decrease varies from element to element. Therefore, it is necessary to periodically charge the energy storage elements constituting the energy storage unit individually or in parallel-connected units to full charge or to a charge rate preset for the energy storage unit, thereby reducing deviations in the energy storage element group caused by self-discharge, leakage current, etc.

[0058] For the reasons described above, the present invention provides a further storage step for the storage unit that takes these points into consideration, i.e., a charging method for the storage unit based on steps S10 to S13 in which all of the storage element groups are fully charged, as a first supplementary charging method, and also provides a second supplementary charging method for the storage unit based on steps S20 to S26 in which the storage element group with the lowest stored amount of electricity based on the self-discharge and leakage current described above is given priority and individually charged, and the storage element groups with the lowest stored amount of electricity are individually charged in order of decreasing remaining amount of electricity, and the first supplementary charging method and the second supplementary charging method can be selectively implemented depending on the charging time at that time and the use of the storage unit after charging.

[0059] In addition, the second supplementary charging method for the storage unit can appropriately select from among multiple storage element groups if they are specified in advance, or from among all storage element groups if no storage element groups are specified, a so-called shortcut method of individual charging of storage element groups that shortens the charging time by, for example, fully charging the storage element groups in order from the lowest voltage side, or individually charging only the required number of storage element groups in order of the storage element groups with the least remaining charge.

[0060] Fig. 3 is a flowchart of a first supplementary charging method for an energy storage unit in which all of the energy storage element groups constituting the energy storage unit are individually charged, following Fig. 2. Note that, in the explanation based on this flowchart, as in the explanation based on Fig. 2 above, the explanation will be given on the premise that the energy storage unit is configured using capacitors as the energy storage elements shown in Fig. 1 and capacitor groups as the energy storage element groups.

[0061] When starting the routine of the first supplementary charging method for this storage unit, a single storage element Cx (x is an integer from 1 to n) to be charged first is selected from the specified storage element group if specified, or arbitrarily (for example, in the order of the storage element group numbers) if not specified, and at the same time, only the switches necessary to simultaneously measure the terminal voltage of the storage element group Cx are closed (step S10).

[0062] Specifically, only the switches SWC(x) and SWD(x) corresponding to a specific storage element group Cx are closed, and the other switches SWU, SWD, SWC(y), and SWD(y) (where y is an integer between 1 and n excluding x) are open. In other words, all switches except those corresponding to the storage element group Cx are open.

[0063] Next, current is passed through the selected storage element group Cx to charge it and measure the terminal voltage, and charging continues until the storage element group indicates full charge. When full charge is reached, charging is terminated and the switches that were used to charge and measure the terminal voltage are opened to disconnect the storage element group (step S11).

[0064] The fact that the charging of the selected storage element group has been completed is recorded (step S12).

[0065] Next, another group of storage elements is selected and the same procedure as above (switching on and off of the switch SW) is performed to fully charge this group of storage elements.

[0066] The above steps are repeated, and if a storage module is specified, it is determined whether charging of the specified storage element group is complete; if not, it is determined whether charging of all storage element groups is complete. If charging of the storage element group to be charged is not yet complete, the next storage element group to be charged is selected and specified, and the process returns to step S11 to continue charging the uncharged storage element groups. On the other hand, if charging of all storage element groups to be charged is complete, the charging operation of the first supplementary charging method for the storage unit is terminated (step S13). Note that display etc. is optional.

[0067] This first supplemental charging method for the energy storage unit is based on the same concept as the basic charging method for the energy storage unit described above. Specifically, the change in terminal voltage is a function of the voltage of the parallel-connected energy storage element group and the amount of charge possessed by each energy storage element group. When the energy storage element is a capacitor, the relationship Q = C·V holds between the amount of charge Q, the increased terminal voltage V, and the capacitance C of the energy storage element group connected in parallel. Therefore, the capacity and charge or power that can be charged for each energy storage element group connected in parallel can be easily calculated. Furthermore, the maximum and minimum capacities of the energy storage element groups can also be calculated. As a result, it is possible to calculate the allowable charge amount for each energy storage element group individually, as is obvious.

[0068] Next, a second supplemental charging method for an energy storage unit, which is a supplemental charging method different from the first supplemental charging method, will be described. Fig. 4 is a flow diagram of the second supplemental charging method for an energy storage unit, following Fig. 2 and Fig. 3, in which a specific energy storage element group or all of the energy storage element groups constituting the energy storage unit are individually charged. Note that, as with the above-mentioned explanations based on Fig. 2 and Fig. 3, the explanation based on this flow diagram will also be given on the premise that the energy storage unit shown in Fig. 1 is configured using capacitors as the energy storage elements and capacitor groups as the energy storage element groups.

[0069] This charging routine is intended to be performed after charging according to the routine for basic charging has been completed, i.e., after the above-mentioned storage unit has been charged based on steps S1 to S7, or by this charging routine alone. First, the charging unit control unit 260 checks the instructions given by the storage mode selection unit 270, and if there is an instruction to measure the terminal voltage of the storage element group, it operates the voltage measurement switch group SWD(x) (x is an integer from 1 to n) to measure the terminal voltage of all storage element groups that make up the storage module and records them together with the storage element group number in order of lowest terminal voltage. If there is no instruction, this step is terminated without doing anything (step S20).

[0070] Next, the group of storage elements to be charged is selected. Whether a specific group of storage elements or all groups of storage elements is to be charged, and whether the charging order is to be in ascending order of terminal voltage of the storage elements to be charged (i.e., in ascending order of stored charge amount) or in order of storage element number, etc., is determined in accordance with the information received from the charging mode selection unit 270 via the charging unit control unit 260 (step S21).

[0071] First, the switches necessary for charging the designated group of storage elements and measuring the terminal voltage are closed, and then the charging operation begins. The charging operation and measurement of the terminal voltage are continued, and when the group of storage elements is fully charged, the contacts of all switches related to the charging of the group of storage elements are opened, and the fact that the charging of the group of storage elements has been completed is recorded, and the charging operation ends (step S22).

[0072] First, it is confirmed whether charging of all specified storage element groups has been completed using the charging completion information of the storage element groups.If charging of the storage element group to be charged has not yet been completed, the next storage element group to be charged is designated in accordance with conditions such as the instruction information of the storage mode selection unit 270, the charging completion information of the storage element group, information on whether charging of the storage element group is required, and information on the terminal voltage of the storage element group, and then the process returns to the beginning of step S22.If it is determined that charging of all target storage element groups that make up the storage unit has been completed, the second supplementary charging operation is completed (step S23).

[0073] It should be noted that the treatment of storage element groups other than the designated storage element group that have not yet been fully charged will be in accordance with the concept of device operation.

[0074] By going through the above-described routine, the basic charging of the power storage unit can be performed, and then supplemental charging 1 or supplemental charging 2 can be selectively performed depending on the conditions and environment required for the supplemental charging. This makes it possible to solve all the problems described above in the "Problems to be Solved by the Invention" section at once.

[0075] Although the above-mentioned energy storage unit has been described in text and in drawings using capacitors as energy storage elements and a group of capacitors as a group of energy storage elements, more specifically, it can be said that the most suitable capacitors for application to the present invention are so-called electric double layer capacitors, which are all dischargeable. By applying an electric double layer capacitor as the capacitor to the present invention, a capacitor of several thousand to several tens of thousands of farads can be configured as an energy storage unit.

[0076] In addition to the large storage capacity mentioned above, the features of an energy storage unit that uses a capacitor as the energy storage element include the ability to charge quickly in an extremely short time, almost no performance degradation even with repeated charging and discharging, resulting in a cycle life of several million cycles, high output density, no limit on the depth of discharge (i.e., complete discharge is possible), and a wide usable temperature range.

[0077] Therefore, it has an advantage in that it can serve as an emergency power source (backup power source) in the event of a momentary power outage, such as when the power supply is momentarily interrupted due to a relatively large load in a poor surrounding environment.

[0078] However, the present invention can also be applied to an energy storage unit that uses a lithium ion secondary battery as the energy storage element, which functionally needs to retain a certain amount of charge during use, because it basically has the same properties as a capacitor, except for the functional need to retain a certain amount of charge.

[0079] The energy storage element used in the energy storage element charging method according to the present invention is not limited to a capacitor. That is, in the energy storage unit charging method according to the present invention, a plurality of capacitor groups each consisting of parallel-connected capacitors are connected in series to form an energy storage unit, but the energy storage element is not particularly limited to a capacitor, and can also be applied to other energy storage elements, such as chemical secondary batteries, for example, lithium-ion secondary batteries, lead-acid batteries, and nickel-metal hydride secondary batteries.

[0080] Here, when the storage elements are chemical secondary batteries such as lithium-ion secondary batteries, lead-acid batteries, or nickel-metal hydride secondary batteries, it is necessary to understand the charge and discharge characteristics of the constituent storage batteries in advance (see the voltage-charge characteristic diagram in Figure 5(b)). Then, by calculating the amount of change from the individual voltage values ​​of each group of storage elements connected in parallel before and after the application of charge Q, the current allowable charge amount of each storage element group is calculated, and the allowable charge amount of the storage unit is determined, and this charge amount is sent to the storage units connected in series to charge them.

[0081] For example, if the energy storage elements are lithium-ion batteries, even if any one of the energy storage elements or the group of energy storage elements is completely discharged or discharged below a specified lower limit voltage, it will no longer be usable as an energy storage unit. Therefore, by combining the basic charging method of the present invention with the first supplemental charging method or the second supplemental charging method, the energy storage unit can be used for a long period of time by reliably preventing the complete discharge or discharge below a specified lower limit voltage of any of the energy storage elements or the group of energy storage elements that make up the energy storage unit. In other words, as described above, even if the energy storage elements are chemical secondary batteries, the effects of the present invention can be fully achieved as long as they are used in a manner that does not adversely affect the chemical secondary batteries. Therefore, it should be emphasized that the effects of the present invention can be fully achieved even if each of the energy storage elements constituting the energy storage element group in the present invention is a chemical secondary battery instead of a capacitor. Therefore, even if each of the energy storage elements is a chemical secondary battery, the effects of the present invention can be fully achieved. Therefore, it should be emphasized that even if each of the energy storage elements is replaced with a chemical secondary battery, the scope of the present invention also falls within the scope of the present invention.

[0082] It goes without saying that the circuit block diagrams, flow charts, and other explanatory drawings shown in the above-described embodiments are merely examples, and that the structure, materials, circuit configuration, etc. can be appropriately modified within the scope in which the effects of the present invention can be achieved.

[0083] For example, the energy storage unit according to the present invention generally includes all those configured from a group of energy storage elements in which a combination of a plurality of energy storage elements connected in series, parallel, or series-parallel is further connected in series, parallel, or series-parallel as necessary, and the energy storage unit includes all those configured by further connecting each energy storage element group in series, parallel, or series-parallel as necessary.

[0084] Below, we will explain the major differences between an energy storage device in which the energy storage element is a capacitor, so that the energy storage unit itself is a capacitor, and an energy storage device in which the energy storage element is a chemical secondary battery such as a lithium ion battery, so that the energy storage unit itself is a large-capacity secondary battery. First, we will explain the differences that give the energy storage device using a capacitor an advantage over an energy storage element using a chemical secondary battery.

[0085] In principle, a capacitor stores electric charge between electrodes, and therefore has the following advantageous differences (1) to (4) compared to an electric storage element using a chemical secondary battery. (1) In the case of a storage device using a capacitor, the charge moves only between the electrodes, so the internal resistance is small and the delay in operation is inevitably much less than in a storage device using a chemical secondary battery. (2) In the case of a storage device using a capacitor, the allowable current value when discharging is much larger than that of a storage device using a chemical secondary battery, because the device simply transfers charge between the electrodes. Here, the main limiting factor is the resistance value of the capacitor's current path, and this value is largely determined by the physical structure of the product. (3) In the case of a power storage device using a capacitor, since electric charge is stored between electrodes, there are far fewer restrictions on the number of charge / discharge cycles and the operating life compared to a power storage device using a chemical secondary battery. (4) In the case of a storage device using a capacitor, the operating temperature range is overwhelmingly wider than that of a storage device using a chemical secondary battery, since it can operate as long as the movement of charge between the electrodes is not hindered.

[0086] On the other hand, the energy density of capacitor-based energy storage devices is still lower than that of chemical secondary batteries such as lithium-ion batteries. This is because chemical secondary batteries generate electricity through chemical reactions. As a result, secondary batteries have high inter-electrode resistance and high internal battery resistance. Furthermore, because charge is generated through a chemical reaction, there is a delay in operation. Furthermore, secondary batteries are subject to current value restrictions when flowing current in and out in order to keep the reaction rate of the chemical reaction within an appropriate range.

[0087] Specifically, because chemical reactions within the electrodes are utilized, ion migration and reaction time is required, and the resistance due to the chemical reaction is large, limiting the amount of current that can be passed, making them fundamentally different from capacitor-based energy storage devices. In addition, they are significantly limited by heat generation due to the current. In other words, as the temperature rises, the chemical reaction progresses too quickly, which in turn increases heat generation, creating a vicious cycle. To avoid this, heat generation must be strictly controlled within an acceptable range. Furthermore, the current values ​​when flowing in and out of chemical secondary batteries are orders of magnitude smaller than those of capacitor secondary batteries. On the other hand, because capacitor secondary batteries simply physically input and output current, the current values ​​when flowing in and out are significantly larger than those of chemical secondary batteries.

[0088] As mentioned above, chemical secondary batteries utilize chemical reactions, which inevitably limit the number of charge / discharge cycles and their operating life due to the simultaneous production of unnecessary reaction products. Furthermore, as mentioned above, the operating temperature range of chemical secondary batteries is limited to the temperature range within which chemical reactions are permitted. As a result, chemical secondary batteries are naturally inappropriate for use in low-temperature or high-temperature operating environments. However, lithium-ion batteries have a higher energy density than capacitors.

[0089] For this reason, in a large-scale power storage system, there is an essential difference between a power storage device using a capacitor and a power storage device using a large-capacity secondary battery, such as a lithium-ion battery, as follows. (a) Although the energy density of a capacitor is moderate, the output density is much greater than that of a chemical secondary battery because the maximum current is very large. (b) In order for chemical secondary batteries to handle large amounts of power, they need a corresponding amount of storage capacity. (c) With a capacitor, there is no relationship between the amount of stored electricity and the amount of power, so there are no restrictions in this regard. (d) In a storage device with a storage capacity of 1kw / h (1 hour), a lithium-ion battery can handle any power up to 1kw / h, but cannot handle anything above that, even if the power supply can handle it. On the other hand, in the case of a capacitor, even a 1kw / h storage device can increase the current up to the maximum allowable value of the capacitor for a short period of time depending on the power supply.

[0090] In other words, a storage device consisting of a 1kW / h (1 hour) capacitor can also handle 2kW / 30 minutes, 4kW / 15 minutes, or 12kW / 5 minutes. If the power supply is acceptable, it is theoretically clear that it is possible to dramatically shorten the charging time of a storage device using a capacitor compared to a storage device using a secondary battery such as a lithium-ion battery, and in reality, it is naturally possible to achieve a correspondingly significant reduction in the charging time.

[0091] Finally, to facilitate understanding of the merits of the present invention, some specific examples will be introduced. For example, when the load is large and the power supplied to the load occasionally experiences momentary power outages, the first supplementary charging method is implemented following the basic charging method to fully charge all of the storage element groups individually.

[0092] In other words, if the storage elements are, for example, electric double layer capacitors, and a momentary power outage occurs and the storage unit supplies a considerable amount of power to the load as emergency power, by implementing the first supplementary charging method following the basic charging method described above, all of the storage elements can be fully charged, and they can be used again as a backup power source any number of times (without the limit on the number of times that is imposed on chemical secondary batteries).

[0093] Separately from this, even if a momentary power outage occurs once, if the timing when the next momentary power outage will occur is quite some time away, when the storage unit has stored electricity as emergency power and consumed a considerable amount of charge, it can be determined that there will be no immediate need to supply further emergency power, and in preparation for the next momentary power outage, the first supplementary charging method can be carried out with some time to fully charge all of the storage elements of the storage unit.

[0094] Furthermore, in cases where the load is not as large as that described above but instantaneous power outages occur frequently, when charging the storage unit, the storage unit is first charged to the minimum required level using the basic charging method, or in addition, the storage unit is prepared as a backup power source with all storage element groups fully charged using the first supplementary charging method.

[0095] Then, after the power storage unit is installed as a backup power source, if a momentary power outage occurs, it will supply the necessary and sufficient amount of power to the load in order to quickly return to a state where it can function as the next backup power source.

[0096] After the energy storage units are thus functioning as backup power sources, in preparation for the next momentary power outage, which may occur again in a short span of time, the energy storage units are fully charged in order as quickly as possible, as many as necessary, starting with the energy storage element group with the least amount of stored energy, using the second charging method.

[0097] In this way, in order to have the energy storage unit function as a backup power source again in preparation for the next momentary power outage, which may occur at any time, the second supplementary charging method is implemented to quickly charge the energy storage unit with the necessary and sufficient charge. As a result, even if such momentary power outages occur frequently after one power outage, the energy storage unit can adequately respond to these and supply the necessary power to the load during the momentary power outage.

[0098] Furthermore, by charging an electricity storage unit consisting of a capacitor in a short time using the basic charging method, the present invention allows for easy and repeated charging in a short time many times throughout the day, making it extremely convenient for everyday life in which various errands must be run not far from home, for example, by an electric vehicle, an electrically assisted bicycle, an electric motorcycle, an electric moped, etc. In addition, by performing basic charging of the electricity storage unit according to the present invention, rapid charging is possible and a large current can be supplied that is sufficient to handle the large torque required when starting a mobility vehicle, etc.

[0099] Furthermore, even if the energy storage unit has not been used for a certain period of time, the first supplementary charging method or the second supplementary charging method can be used to fully charge all of the energy storage elements of the energy storage unit, and then this can be used to rapidly charge a means of transportation such as the above-mentioned electric vehicle, and a large current can be supplied that is sufficient to handle the large torque required when the mobility starts moving.

[0100] The reason for selecting the first supplemental charging method or the second supplemental charging method as appropriate based on the usage pattern of the energy storage unit is that even if a basic charge that is sufficient for use is performed as described above, if the energy storage unit is not used for a long period of time, the amount of charge in the energy storage unit will gradually decrease due to natural discharge, etc., and this method was conceived as a countermeasure against this.

[0101] For example, if a situation arises in which it is necessary to move quickly using mobility within a short distance, the group of storage elements is individually charged using the second supplementary charging method for this urgent, short-distance movement using mobility.

[0102] In this case, as described above, the group of storage elements having the least amount of charge stored at that time is fully charged first, followed by the group of storage elements having the next least amount of charge stored therein. Such individual charging of each group of storage elements is carried out according to the procedure of the second supplementary charging method, and for the time being, the minimum number of storage element groups necessary for the time being among the groups of storage elements constituting the storage unit are charged.

[0103] Specifically, the amount of charge corresponding to the power to be supplied from the storage element group is determined by a control means (not shown) for each of the plurality of individual storage element groups that can store electricity, and second individual charging is performed.

[0104] On the other hand, for example, if there is a certain amount of time before the storage unit is used again to supply power from the storage unit, and in addition, if the mobility powered by the storage unit must travel a long distance, it is preferable to fully charge all storage elements using the first supplementary charging method.

[0105] This makes it possible to charge the charging unit by the basic charging method, and then to fully charge the storage unit itself by completely replenishing the charge that has been lost due to self-discharge, leakage current, etc.

[0106] Furthermore, if it is not possible to predict the time until the storage unit will actually be used, the second supplemental charging is carried out to fully charge as many storage element groups as time permits, starting with the storage element group with the least amount of charge and continuing until the storage element group with the least amount of charge is fully charged individually.

[0107] This allows the appropriate amount of charge to be charged to the power storage unit depending on the time until the power storage unit is actually used. In other words, when there is not enough time, the minimum number of power storage element groups required can be fully charged for the time being, and when there is more time, all power storage element groups can be fully charged, thereby improving usability.

[0108] The above is an example of a method for charging the power storage unit made up of the capacitor secondary battery of this embodiment. However, in addition to this, for example, when the engine serving as the main power source of construction machinery used in harsh environments serves as a backup power source for operating a safety actuator in the event of an emergency stop for some reason of the engine, which serves as the main power source, it is possible to make effective use of the power storage unit by using the above-mentioned basic charging method, first supplemental charging method, and second supplemental charging method alone or in appropriate combinations depending on the magnitude of the load required to drive this safety actuator and the frequency of trouble occurring in the engine serving as the main power source.

[0109] Furthermore, when supplying power to power generation facilities that utilize natural energy sources such as wind power generation and solar power generation, the amount of power generated by such facilities depends on the natural environment and is therefore subject to considerable fluctuations based on the weather conditions at the time. In other words, there is an essential problem with power generation facilities that use natural energy sources; they are unable to generate power stably with a constant inertia.

[0110] Due to these unique circumstances, when the amount of electricity generated by the power generation equipment using natural energy is large due to its operating conditions, the amount of electricity generated will far exceed the amount of electricity that needs to be supplied at that time, and the surplus will be charged into a capacitor storage device.

[0111] Similarly, if the amount of power generated by a power generation facility that uses natural energy decreases due to its operating status, the amount of power generated will fall far short of the amount of power that needs to be supplied at that time. Therefore, by supplying the shortfall from the capacitor storage device charged as described above, it becomes possible to supply a stable amount of power, similar to hydroelectric or thermal power generation, for example.

[0112] In such cases, by implementing the charging method for a storage unit comprising a capacitor secondary battery according to the present invention, it is possible to realize a stable supply of power tailored to each power generation facility by combining the capacitor storage battery and the charging method for a storage unit comprising a capacitor secondary battery according to the present invention, which is the most preferred charging method based on the individual type of power generation facility that utilizes natural energy under various natural conditions, i.e., the basic charging method, first supplemental charging method, and second supplemental charging according to the present invention, taking into account the individual generation situation of power generation amount based on weather conditions and the type of power generation facility.

[0113] However, as mentioned above, even if each storage element constituting the storage element group in the present invention uses a chemical secondary battery instead of a capacitor, the sufficient effects of the present invention can be achieved to a certain extent, so it should be emphasized that even if each storage element is replaced with a chemical secondary battery, it is still within the scope of the present invention. [Explanation of symbols]

[0114] 100 Energy Storage Units 200 Power storage unit control section 210 Collective charging power supply unit 220 Individual charging power supply section 250 Voltage detection unit 260 Switch control section 270 Charging mode selection section Switches SWU-1, SWU-2 Switches SWC(1-1), SWC(1-2) Switches SWC(2-1), SWC(2-2) Switches SWC(3-1), SWC(3-2) Switches SWC(n-1), SWC(n-2) Switches SWD-1, SWD-2 Switch SWD(1-1),SWD(1-2) Switch SWD(2-1),SWD(2-2) Switch SWD(3-1),SWD(3-2) Switch SWD(n-1),SWD(n-2) Capacitors C1-1, C1-2, C1-3, C1-(a-1), C1-a Capacitors C2-1, C2-2, C2-3, C2-(b-1), C2-b Capacitors C3-1, C3-2, C3-3, C3-(c-1), C3-c Capacitors Cn-1, Cn-2, Cn-3, Cn-(x-1), Cn-x

Claims

1. A method for charging a storage unit comprising a capacitor secondary battery configured by connecting a single storage element comprising a capacitor, or a group of multiple storage elements connected in parallel, or m sets (m is a natural number) of storage elements further connected in series, parallel, or series-parallel, comprising: Step S1 of measuring the inter-terminal voltages of each of first to n-th (n is a natural number of 2 or more) energy storage element groups constituting the energy storage unit; Step S2: flowing a predetermined charge δQ into first to n-th series-connected storage element groups to identify the storage element group with the smallest storage capacity among the storage element groups, thereby accumulating the charge δQ for each storage element group; Step S3 of measuring the terminal voltages of each of the storage element groups after the charge δQ is applied to each of the storage element groups in accordance with step S2; Step S4: calculating, for each storage element group, the amount of change between the inter-terminal voltage measured at the time of specifying the charge capacity in step S3 and the terminal voltage measured in step S1; In step S4, an attempt is made to identify the storage element group with the largest change in terminal voltage for each storage element group, i.e., the storage element group with the lowest storage capacity. If it is determined that the storage element group with the lowest storage capacity cannot be identified under the conditions at this time and the number of times steps S2 to S5 are repeated is less than a preset value, step S5 stores the terminal voltage information of the storage element group, adds 1 to the number of times it is repeated, and then returns to step S2, and if the number of times it is repeated exceeds a predetermined number, it performs a process of terminating the charging operation according to this procedure. Step 6: estimating and calculating the amount of charge required for the storage element group with the lowest storage capacity to be fully charged based on the identification information of the storage element group with the lowest storage capacity; A method for charging a power storage unit comprising a capacitor secondary battery, comprising: step S7 of providing the amount of charge calculated in step S6 to the power storage unit, and completing the charging operation of the power storage unit upon completion of the providing operation.

2. A charging method for fully charging a group of storage elements that have not yet reached full charge after charging a storage unit made of a capacitor secondary battery, or for fully charging a group of storage elements solely by this claim, and for specifying a specific group of storage elements and a charging order when charging, When the charging operation starts, each storage element group constituting the storage unit is handled according to instructions from a higher-level device, etc., and if there is an instruction as to whether or not each storage element group needs to be charged, that is used; if there is no instruction, all storage element groups are treated as specified; and if there is a specification for the charging order, that is used (in order of lowest inter-terminal voltage, in order of specified number, etc.); if there is no specification, charging is performed on the specified storage element group from a predetermined storage element group (for example, in order of lowest element group number), and in step S10, the storage element group to be charged first is selected according to the instructions, and a switch for charging and a switch for measuring the inter-terminal voltage are operated; In accordance with the instructions, first, the switches instructed for charging the storage element group and measuring the terminal voltage are closed, and charging is continued until the storage element group is fully charged. When it is determined that the storage element group is fully charged, the switches for detecting the voltage and charging are opened in step S11. Step S12: storing the fact that the charging of the storage element group selected in step S11 has been completed; A method for charging a storage unit consisting of a capacitor secondary battery, characterized in that, based on the record of step S12, it is determined whether charging of all designated storage element groups has been completed, and if it is determined that charging of all designated storage element groups has been completed, the charging operation is completed, and if not, the storage element group to be charged next is selected from the storage element groups that have not yet been charged, and switches required for charging are operated, and the method returns to step S11 and repeats steps S11 to S13.

3. This is a charging method for charging a capacitor secondary battery, which can fully charge a group of storage elements that have not yet reached full charge or a group of storage elements that meet specific conditions, and first, when there is an instruction from a higher-level device or the like, operates a group of switches for measuring terminal voltages of each storage element group that constitutes the storage unit, measures the terminal voltage of each storage element group, and then records information on the storage element numbers in order of lowest terminal voltage, and does not perform the above-mentioned operation if there is no instruction; If there is an instruction from the higher-level device, step S21 is performed to specify the storage element group to be charged first in accordance with the voltage information of the storage element groups arranged in ascending order of inter-terminal voltage recorded in step S20, information on whether each storage element group needs to be charged, instruction information on the charging order, etc. In step S22, the contacts of the switches required to charge the storage element group designated in step S21 while measuring the terminal voltage of the storage element group are first closed, and then the charging and terminal voltage measurement are continued until the storage element group is fully charged, and after the storage element group is fully charged, all the contacts of the switches are opened to complete charging of the storage element group. At this point, it is determined whether charging of the designated group of storage elements has been completed, and if charging has been completed, the contacts of all switches are opened and the charging operation is terminated, and if charging of the designated group of storage elements has not yet been completed, the next group of storage elements to be charged is designated in accordance with the instructions from among the designated group of storage elements, and then the method for charging a storage unit consisting of a capacitor secondary battery is further characterized by comprising step S23.

4. 4. The method for charging an electricity storage unit according to claim 1, wherein each of the electricity storage elements constituting the electricity storage element group is a chemical secondary battery instead of a capacitor.

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