POWER SUPPLY DEVICE AND BATTERY DETERIORATION DEGREE DETERMINATION SYSTEM

To provide a power supply device and a battery deterioration degree determination system that enables continuous use of stable electric power even if used battery cells of various deterioration degrees are used. A power supply device for performing charging from a charging part and discharging from a discharging part includes plural battery units including plural battery cells connected in series or in parallel, a connection selection part configured to select at least one of the battery units to be connected to the charging part or the discharging part, an accommodation part configured to detachably accommodate each of the battery units. The battery cells are classified into plural deterioration ranks according to a deterioration degree, and the battery cells included in one of the battery units have the same deterioration rank.

TECHNICAL FIELD

The present invention relates to a power supply device and a battery deterioration degree determination system, and more particularly, to a power supply device and a battery deterioration degree determination system capable of replacing plural battery units.

BACKGROUND ART

In recent years, there is a growing use of electric objects, hybrid cars, and electric motorcycles using electric power as a power source for mobile objects (e.g., automobiles, motorcycles) and converting the power supplied from a secondary battery into kinetic energy. Further, the adoption rate of power-assisted bicycles using electric power as an auxiliary power source of the bicycle is also increasing.

Because these mobile objects use the electric power stored in the secondary battery mounted on the mobile objects, their travel distance is determined by the chargeable capacity of the secondary battery. In order to increase the travel distance of the mobile object, it is effective to increase the capacity by increasing the size of the secondary battery. However, it is known that the chargeable capacity of the secondary battery deteriorates according to its used environment and its use history. Further, the travel distance of the mobile object gradually becomes shorter in comparison with the travel distance of a brand new secondary battery.

Thus, it is proposed to individually measure the degree of deterioration of secondaries batteries and replace a secondary battery whose deterioration has progressed more than a predetermined degree with a new secondary battery, so that the travel distance of the mobile object can be maintained. Further, it is also proposed that a deteriorated secondary battery be collected by a collector company and reused as a reusable product or a rebuilt product after it has been subject to performance recovery and reassembly (For example, see Patent Document 1).

FIG.9is a schematic diagram illustrating a conventionally proposed model for collecting a secondary battery. In this drawing, the proportion of a chargeable capacity of a battery cell compared to that of a new battery cell is illustrated in percentages. In other words, assuming that the chargeable capacity at the time of a new product is indicated as 100% (deterioration degree of 0%), deterioration degree would be 100%−(chargeable capacity %).

In the example illustrated inFIG.9, a battery cell with a chargeable capacity of 100% can be used in new cars, and a battery cell with a chargeable of 90% (deterioration degree of 10%) is used for used cars or sold as a used secondary battery. Further, a battery cell with a chargeable capacity of 70-80% (deterioration level of 20-30%) is used for applications other than mobile objects, such as a power supply for a streetlight because it is difficult to ensure a sufficient travel distance compared to a new battery. Further, because it is difficult for a battery cell whose chargeable capacity has deteriorated to approximately 10% (deterioration degree of 90%) to be reused in other applications, they are disassembled and have their raw materials recycled.

As described above, with the conventional art, a battery cell whose deterioration has not progressed substantially can be reused whereas a battery cell whose deterioration is significant can be recycled. Thereby, resources can be efficiently used.

RELATED ART DOCUMENTS

Patent Documents

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

However, with the conventional art, it is difficult to maintain a chargeable capacity with respect to those having a chargeable capacity of approximately 20% to 60% (deterioration degree of 40% to 80%) because deterioration progresses even in reuse. Thus, it is a problem that the application for reuse is limited. In addition, when deterioration of a reused battery cell further progresses, the deterioration degree eventually becomes 90% or more, and it becomes impossible to use the battery cell even for applying it for reuse. Thus, difficulty in attaining a stable power supply is also a problem.

However, the present invention is provided in view of the above-described conventional problem and aims to provide a power supply device and a battery deterioration degree determination system that enables continuous use of a stable power supply even in a case of using used battery cells of various deterioration degrees.

Means for Solving the Problem

In order to solve the above-mentioned problems, the power supply device of the present invention is characterized in that a power supply device for performing charging from a charging part and discharging from a discharging part includes plural battery units including plural battery cells connected in series or in parallel, a connection selection part configured to select at least one of the battery units to connected to the charging part or the discharging part, an accommodation part configured to detachably accommodate each of the battery units, wherein the battery cells are classified into plural deterioration ranks according to a deterioration degree, and the battery cells included in one of the battery units have the same deterioration rank.

With the power supply device of the present invention, because the battery cells included in the battery unit have the same deterioration rank, each battery unit can be appropriately used in charging and discharging even if battery cells having different deterioration degrees are used. This enables continuous use of stable electric power even if used battery cells of various deterioration degrees are used.

Further, according to one aspect of the present invention, there is further included a deterioration measurement part configured to measure the deterioration degree of the battery cells included in the battery unit, and a unit replacement notification part configured to transmit a unit replacement signal based on a measurement result of the deterioration measurement part.

Further, according to one aspect of the present invention, the unit replacement notification part is configured to transmit the unit replacement signal in a case where a charge capacity of any one of the battery cells is equal to or less than a first threshold value.

Further, according to one aspect of the present invention, the connection selection part is configured to exclude the battery unit included in the battery cell having a charging capacity equal to or less than the first threshold value from a selection target.

Further, according to one aspect of the present invention, the unit replacement notification part is configured to calculate a sum of a chargeable amount of electricity of plural the battery units accommodated in the accommodation part as a total charge amount, and transmit the unit replacement signal in a case where the total charge amount is equal to or less than a second threshold value.

Further, according to one aspect of the present invention, the deterioration measurement unit is configured to measure the deterioration degree based on electrical characteristics at a time of charging or discharging of the battery unit.

Further, according to one aspect of the present invention, a photovoltaic power generating part for generating electricity by light is connected to the charging part.

In order to solve the above-mentioned problems, a battery deterioration degree determination system for determining deterioration of a used battery element is characterized in that the battery deterioration degree determination system includes a management server configured to record identification data of the battery element in association with usage history data, and a deterioration determination part configured to measure a first electrical characteristic at a time of charging or discharging of the battery element, determine a first deterioration degree based on a measurement result of the first electrical characteristic and the usage history data, and record the identification data in association with diagnosis data including the first deterioration degree in the management server.

With the battery deterioration degree determination system according to the present invention, by determining the deterioration degree based on the electrical characteristics and the usage history data of the battery element, accurate determination of the deterioration degree can be achieved by considering not only the status of the battery element at the time of measurement of the electrical characteristics but also considering the usage history from the time of the manufacturing of the battery element.

Further, according to one aspect of the present invention, the deterioration determination part is configured to measure a second electrical characteristic at a time of charging or discharging of the battery element after a lapse of a predetermined period, update the usage history data, determine a second deterioration degree based on a measurement result of the second electrical characteristic and the usage history data, and update the diagnosis data by adding the second deterioration degree to the diagnosis data.

Further, according to one aspect of the present invention, the deterioration determination part is configured to analyze a relation between the usage history data and the diagnosis data regarding plural battery elements by machine learning, and update a method for determining the first deterioration degree and the second deterioration degree based on a result of the analysis.

Effects of the Invention

According to the present invention, it is possible to provide a power supply device that enables continuous use of stable electric power even in a case of using used battery cells of various deterioration degrees.

MODES FOR CARRYING OUT THE INVENTION

First Embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes illustrated in the respective drawings are denoted by the same reference numerals, and duplicate descriptions are omitted as appropriate.FIG.1is a block diagram schematically illustrating a configuration of a power supply device100according to this embodiment. As illustrated inFIG.1, the power supply device100includes plural battery units10a-10e, an accommodation part20, a control part30, a connection selection part40, a deterioration measurement part50, a unit replacement notification part60, a charging part70, and a discharging part80. Further, a solar panel90is connected to the charging part70, and a load91is connected to the discharging part80.

Each battery unit10a-10eis a secondary battery in which plural battery cells are electrically connected. Similar to a publicly known secondary battery, each battery unit10a-10eincludes, for example, a terminal for charging and discharging and a BMS (Battery Management System) for controlling the charging and discharging. As described below, the battery cells included in each battery unit10a-10eare those obtained by reusing the battery cells included in the secondary batteries that were used in a mobile object or the like. Further, each battery unit10a-10ehas a shape enabling it to be detachably accommodated in the accommodation part20and is provided with a structure in which detachment is restricted by a locking mechanism included in the accommodation part20.

The accommodation part20is a part for detachably accommodating and holding plural battery units10a-10eand regulating the attaching and detaching of the battery units10a-10eby actuating the locking mechanism. The shape of the accommodation part20and the structure of the specific locking mechanism is not limited in particular. Publicly known battery attachment/detachment mechanisms may be used. Further, the accommodation part20includes terminals and wires for electrically connecting the battery units10a-10eand the control part30. AlthoughFIG.1illustrates an example in which five battery units10a-10eare accommodated in the accommodation part, the number of battery units that are accommodated is not to be limited.

The control part30is a part for controlling the operation of the connection selection part40, the deterioration measurement part50, and the unit replacement notification part60. The control part30includes a memory (not illustrated) and an external storage device, a central processing unit (CPU: Central Processing Unit) and performs data processing according to a predetermined program to control each part.

The connection selection part40is a part for selecting the battery units10a-10eto be connected to the charging part70or the discharging part80. The connection selection part40switches between connection and disconnection between each of the parts mechanically or electronically. For example, in a case where the connection selection part40connects the battery unit10aand the charging part70and connects the battery unit10eand the discharging part80, the electric power supplied from the solar panel90charges the battery unit10aand the electric power is supplied from the battery unit10eto the load. Although the specific configuration of the connection selection part40is not limited in particular, it is preferable to use a circuit configuration capable of suppressing the instantaneous interruption that stops the supply of power when switching the battery units10a-10econnected to the discharging part80.

The deterioration measurement part50is a part for acquiring data regarding the battery units10a-10econnected to the control part30and measuring the deterioration degree of the battery cells included in the battery units10a-10e. Here, assuming that the chargeable capacity in a state where all of the battery cells are brand new is “brand new capacity” whereas the chargeable capacity in a state where the battery cells10a-10eare reassembled is “deteriorated capacity”, the “deterioration degree” is expressed by the ratio between the deteriorated capacity and the brand new capacity.

Further, “chargeable capacity” indicates the amount of electric power that can be extracted from the time when the battery is fully charged to the time when the battery is fully discharged in a case where full charge and full discharge of the battery are set. In other words, with each of the battery units10a-10e, in a case where a “full charge” (100%) is assumed as a state in which the BMS stops charging by activating an overcharge protection function and a “full discharge” (0%) is assumed as a state in which the BMS stops discharging by activating an overdischarge protection function, the amount of electric power required to charge from “full discharge” (0%) to “full charge” (100%) is the chargeable capacity of each of the battery units10a-10e.

The deterioration measurement part50measures the electrical characteristics of the battery units10a-10eat the time of charging or discharging of the battery units10a-10eand calculates the deterioration degree based on the measured electrical characteristics. The specific method for calculating the deterioration degree is not limited in particular. The electrical characteristics that are measured may be, for example, full charge voltage, full discharge voltage, open circuit voltage, closed circuit voltage, charge characteristic, discharge characteristic, internal resistance, temperature characteristic, load characteristic, cyclic usage history data, or impedance.

The unit replacement notification part60is a part which transmits a unit replacement signal based on the measurement result of the deterioration measurement part50. Here, the unit replacement signal is a signal that notifies the battery unit10a-10eto be replaced to the outside of the power supply device100. The unit replacement signal is a signal transmitted to a transmission target by using publicly known communication methods. The specific configuration of the unit replacement notification part60is not limited in particular. For example, a warning lamp using electrical wiring and a lamp may be used. Alternatively, electronic data communication using a wireless communication method may be used.

The charging part70is a part for receiving electric power from an electric power source connected to the power supply device100. The charging part70includes a connection terminal and an electronic circuit. The charging part70may include a conversion circuit for converting the current value and the voltage value for charging the battery units10a-10e. Further, the charging part70may include a control circuit for controlling the charging of the battery units10a-10e. In particular, when using the solar panel90as an electric power source, it is preferable to include a circuit for performing pulse-width-modulated (PWM: Pulse Width Modulation) control or maximum-power point tracking (MPPT: Maximum Power Point Tracking) control.

The discharging part80is a part for supplying power to the load91connected to the power supply device100. The discharging part80includes a connection terminal and an electronic circuit. The discharging part80may include a conversion circuit for converting the current value or the voltage value of the power supplied from the battery units10a-10e. Further, it is preferable to include a DC/AC inverter-circuit when outputting an alternating current to the load91.

The solar panel90is an electric power source that is connected to the charging part70and supplies electric power to the power supply device100. The solar panel90receives sunlight and converts light energy into electrical energy. Therefore, the solar panel90corresponds to a photovoltaic power generation part in the present invention. Although an example in which the solar panel90is used as the electric power source is described, the configuration of the electric power source is not to be limited as long as electric power can be supplied to the power supply device100through the charging part70. For example, a commercial power supply or other electric power generation devices may be used.

The load91is a device connected to the discharging part80and supplied with electric power from the power supply device100. The specific configuration of the load91is not limited in particular. For example, a lighting device such as a street lamp, an image display device, a wireless communication base station, or a power source such as a pump or a motor may be used. Although this example illustrates the discharging part80connected to the load91, the discharging part80may be connected to a power grid to sell electric power to an electric power company.

FIG.2is a schematic diagram illustrating a model of collecting a secondary battery included in the power supply device100according to this embodiment. In the embodiment illustrated inFIG.2, deterioration degree is calculated by measuring the electrical characteristics of the battery cells included in a collected secondary battery. A battery cell with a chargeable capacity of 20% to 80% (deterioration degree of 20% to 80%) is reused and reassembled into the battery units10a-10e. Here, the method for calculating the deterioration degree at the time of collecting the secondary battery is not limited in particular. However, it is preferable to derive a result equivalent to the result of the calculation of deterioration degree by the deterioration measurement part50, and preferable to perform the same measurement of electrical characteristics and calculation of deterioration degree as those of the deterioration measurement part50. Similar to before, battery cells with 100% chargeable capacity will be used in new cars, and battery cells with 90% chargeable capacity (deterioration degree of 10%) will be used in used cars or sold as used secondary batteries. Further, battery cells with a chargeable capacity of approximately 10% (deterioration degree of 90%) are disassembled and sent to have their raw materials recycled.

FIG.3is a schematic diagram illustrating battery cells included in the battery units10a-10e. As illustrated inFIG.3, each battery unit10a-10eincludes plural battery cells11a-11d,12a-12d,13a-13d,14a-14d,15a-15d. Each of the battery cells11-15is connected in series or in parallel. The number of battery cells11-15included in each battery unit10a-10eis the same, and the connection relation of the battery cells inside the battery units10a-10eis the same.

Further, in a case where the battery cells11-15having different deterioration degrees are connected in series or in parallel, the characteristics of the battery units10a-10ewould be affected by the electrical characteristics of the most deteriorated battery cell among the battery cells11-15. Thus, it would be difficult to utilize the chargeable capacity in correspondence with the deterioration degree of each of the battery cells11-15. However, in this embodiment, although the deterioration degrees of the battery cells11-15included in the battery units10a-10eare different, the ranks of the deterioration degree (deterioration ranks) of the battery cells11-15included in one battery unit10a-10eare the same. Here, the “deterioration rank” represents a classification that is ranked according to the deterioration degree. The rank may be assigned by, for example, rounding a first digit of a percentage.

In the embodiment illustrated inFIG.3, the battery cells11a-11dincluded in the battery unit10ahave a chargeable capacity of 60% (rank of 40% deterioration degree), the battery cells12a-12dincluded in the battery unit10bhave a chargeable capacity of 80% (rank of 20% deterioration degree), the battery cells13a-13dincluded in the battery unit10chave a chargeable capacity of 20% (rank of 80% deterioration degree), the battery cells14a-14dincluded in the battery unit10dhave a chargeable capacity of 50% (rank of 50% deterioration degree), and the battery cells15a-15dincluded in the battery unit10ehave a chargeable capacity of 40% (rank of 60% deterioration degree).

Accordingly, effective utilization of the chargeable capacities corresponding to the respective electrical characteristics of each of the battery units10a-10ecan be achieved by classifying the battery cells11-15according to the deterioration rank and reassembling the battery units10a-10eonly with the battery cells11-15having the same deterioration rank. In the embodiment illustrated inFIG.3, since the four battery cells11a-11dincluded in the battery unit10ahave a rank of 60% deterioration degree, the chargeable capacity of the entire battery unit10ais approximately four times greater than the chargeable capacity of each of the battery cells11a-11d. This similarly applies to the other battery units10b-10e.

Therefore, the chargeable capacity of the battery units10a-10ecan be determined according to the deterioration degree of the respective battery cells11a-11d. Further, the sum of the chargeable electric amount of the battery units10a-10eaccommodated in the accommodation part20can be calculated as a total charge amount. According to the embodiment illustrated inFIG.3, in a case where the chargeable electric amount (capacity) of a single brand new battery cell is 1 kWh, the chargeable electric amount of the battery unit10ais 1×0.6×4=2.4 kWh. Similarly, the chargeable electric amount of the battery units10b-10ewould each be 3.2 kWh, 0.8 kWh, 2 kWh, 1.6 kWh, and the entire power supply device100would be able to charge 10 kWh.

As described above, the chargeable capacity of the power supply device100(total charge amount) is the sum of the chargeable capacities of the battery units10a-10eaccommodated in the accommodation part20. Accordingly, by appropriately combining the battery units10a-10eof various chargeable capacities, the total charge amount of the power supply100can be determined. Thus, even if a battery unit uses a battery cell having a deterioration rank indicating progressed deterioration, the battery unit can be used in combination with another battery unit using a battery cell having a deterioration rank indicating a low deterioration degree, so that the power supply device100can attain a desired total charge amount.

FIG.4is a flow chart illustrating a procedure for managing the battery units10a-10eof the power supply device100. When the driving of the power supply device100is started, the control part30reads a program from a storage device into a memory and executes the following steps starting from step S1. Here, although the program is read from the storage device provided in the power supply device100, it may be a program downloaded via a network.

Step S1is a connection-target selection step for selecting a battery unit10a-10eto be charged or discharged. The control part30acquires data from the BMS regarding the battery units10a-10eaccommodated in the accommodation part20and selects a target to be charged and discharged according to a predetermined order of priorities for charging and discharging. Further, the connection selection part40electrically connects the selected target among the battery units10a-10ewith the charging part70or the discharging part80and disconnects the electrical connection with the unselected battery units10a-10e. After selecting the charge/discharge target and performing connection/disconnection, the procedure proceeds to step S2.

Step S2is a charging/discharging step for performing a charging operation on the selected charging target of the battery units10a-10efrom the charging part70and discharging from the discharging target of the battery units10a-10evia the discharging part80. The specific charging and discharging operations performed by the charging part70and the discharging part80are not limited in particular. Publicly known circuit configurations and controlling methods may be used. The procedure proceeds to step S3while continuing the charging/discharging operations with the charging part70and the discharging part80.

Step S3is a deterioration degree calculation step for calculating the deterioration degrees of the battery cells11-15included in the respective battery unit10a-10e. In the power supply device100, deterioration of the battery cells11-15further progresses by performing the charging operation or the discharging operation in step S2. In the deterioration degree calculation step, the deterioration measurement part50measures the electrical characteristics at the time of the charging operation or the discharging operation of the battery units10a-10eselected as the charging target or the discharging target and calculates the deterioration degree based on the measured electrical characteristics. After the deterioration measurement part50calculates the deterioration degrees, the procedure proceeds to step S4.

Step S4is a unit deterioration determination step in which the battery cells10a-10eof the battery units to be excluded from charge/discharge are determined based on the deterioration degrees of the battery cells11-15of the battery units10a-10ecalculated in the deterioration degree calculation step. The control part30compares the chargeable electric amounts (charge capacity) obtained from the deterioration degrees of the battery cells11-15calculated by the deterioration measurement part50with a predetermined determination criterion and determines whether the battery units10a-10ecorrespond to an exclusion target. If a battery unit10a-10ecorresponding to the exclusion target exists, the procedure proceeds to step S5, and if it does not exist, the procedure proceeds to step S6. In the example illustrated inFIG.4, a threshold value of the charge capacity (first threshold value) is determined beforehand as the determination criterion. The criterion is whether the charge capacity of any of the battery cells11-15is equal to or less than the first threshold value. As an example, the first threshold value may be assumed to be 10% (deterioration degree of 90% or more) of the charge capacity at the time of a brand new state.

Step S5is an exclusion target determination step in which the battery unit10a-10edetermined to correspond to an exclusion target in the unit deterioration determination step is excluded from the targets to be subject to the charging operation and the discharging operation. The control part30records that the battery unit10a-10edetermined as the exclusion target in the unit deterioration determination step is the exclusion target in the storage device and excludes the battery unit from the targets to be selected for charging operation and discharging operation in the subsequent connection target selection step. After the control part30records the exclusion target, the procedure proceeds to step S7.

Step S6is a total charge amount determination step for determining whether the chargeable electric amount (total charge amount) of the entire power supply device100is maintained. The control part30calculates the total charge amount of the battery units10a-10eaccommodated in the accommodation part20based on the deterioration degrees of the battery cells11-15of the battery units10a-10ecalculated in the deterioration degree calculation step. In a case where the calculated total charge amount is lower than a predetermined threshold value (second threshold value), the procedure proceeds to step S7. In a case other than the aforementioned case, the procedure proceeds to step S1.

Step S7is a replacement notification step for prompting replacement of the battery units10a-10e. The unit replacement notification part60transmits a unit replacement signal to the outside of the power supply device100to indicate that a battery unit10a-10eselected as an exclusion target in the unit deterioration determination step exists or that the total charge amount is below the second threshold value. At the same time, it is notified which battery unit10a-10eis excluded as the exclusion target, and a battery unit having the greatest deterioration and low charge capacity is notified to be a replacement target. Further, the battery unit10a-10enotified as the replacement target is excluded from the charging/discharging targets for the charging/discharging operations. In addition, the locking mechanism of the accommodation part20is released, so that the battery unit10a-10enotified as the replacement target can be removed.

A collector company receiving the unit replacement signal newly prepares a reassembled battery unit10, takes out the battery unit10a-10eto be replaced from the accommodation part20, and replaces it with the newly prepared battery unit10. After the unit replacement notification part60transmits the unit replacement signal, the procedure proceeds to step S8.

Step S8is a continuation determination step for determining whether to continue the charging and discharging operations. The control part30determines whether to continue the charging and discharging operations based on, for example, the power supplied from the electric power source connected to the charging part70and the connection status of the load91. In a case where it is determined to be continued, the procedure proceeds to step S1. In a case where it is determined to not be continued, the control operation is terminated.

FIG.5is a schematic diagram illustrating an example of a power supply system using the power supply device100. In the power supply device100, the solar panel90serving as the electric power source is connected to the charging part70, and a lighting device is connected as the load91to the discharging part80. Further, the power supply device100is data-communicably connected to the management server110via a network. With the power supply system as illustrated inFIG.5, the power supply device100can be charged by electric power generated in the solar panel90and the load91can be driven by the electric power charged in the power supply device100even in remote areas where securing a commercial power supply is difficult.

The management server110is a data processing device operated by a collector company that collects secondary batteries and reassembles the battery unit10. The management server110receives the unit replacement signal transmitted by the unit replacement notification part60via a network. The collector company receiving the unit replacement signal removes and retrieves the battery unit10a-10edetermined as the replacement target. Further, the collector company disassembles the retrieved battery unit and sends it for recycling its raw material. Further, the newly prepared battery unit10is accommodated in the accommodation part20to be subject to charging and discharging operations in a subsequent charging/discharging step. Because the newly prepared battery unit10has a charge capacity larger than that of the battery unit10a-10eremoved as a replacement target, the total charge amount of the power supply device100can be maintained. Further, because the battery unit10a-10ethat is determined as the replacement target is excluded from the targets of the charging/discharging operation, the charging operation and the discharging operation can be continued even during the replacement with the new battery unit10.

In the above-described embodiment, because a portion of the battery units10a-10eis replaced with the newly prepared battery unit10, the total charge amount of the entire power supply device100can be maintained and stable electric power can be continuously used. Further, because the total charge of the plural battery units10a-10eis ensured by the battery unit10using used battery cells11-15of various deterioration degrees, the battery cells11-15that have a progressed deterioration degree and a small charge capacity can be effectively utilized.

Second Embodiment

Next, a second embodiment of the present invention is described with reference toFIG.6toFIG.8. Details overlapping with those of the first embodiment are omitted. This embodiment is different from that of the first embodiment in that usage history data of the battery cell is referred for accurately determining the deterioration degree of the battery cell.

FIG.6is a schematic view illustrating a battery reuse step according to this embodiment. In the present embodiment illustrated inFIG.6, a used battery210is removed from a battery using apparatus200and plural battery elements220included in the used battery210are disassembled individually. While a charging or discharging operation is being performed, the deterioration degree of each individual disassembled battery element220is calculated by measuring the electrical characteristics of each individual disassembled battery element220. Based on the calculated deterioration degree, the battery elements220are graded into plural ranks and classified into, for example, ranks A to C. The graded battery elements220are accommodated in the accommodation part20and assembled as a new battery to be used for the power supply device100. Similar to the first embodiment, the battery elements220of the same rank may be connected in series or in parallel to form the battery unit10a-10e.

The battery using apparatus200is an apparatus that is driven by the electric power stored in the secondary battery (cell) such as an electric vehicle or a hybrid car. In the battery using apparatus200, the usage environment and usage status of the battery being used are recorded as historical data. The data that is recorded as historical data may be, for example, the number of times of charging, the number of times of discharging, the usage environment temperature, the usage hours, and SOH (State of Health). Particularly, with a mobile object such as an electric vehicle, the historical data should preferably include driving history such as travel distance, travel history, the number of times of acceleration, travel speed, and the number of times of brakes.

The used battery210has an identification number that is assigned to each individual battery. The historical data and the identification number of the battery using apparatus200are associated with each other and recorded in the storage device of the battery using apparatus200. The used battery210includes plural battery elements220that are electrically connected to each other. The plural battery elements220are collectively controlled as a single cell whose charging and discharging are controlled by the BMS (Battery Management System).

The battery element220is an element included in plural in the used battery210as a battery unit or a battery cell. Because the battery elements220are not provided with an individual BMS, it is preferable to add a new BMS to the battery element220for measuring their electrical characteristics and managing their charging and discharging. Further, each battery element220is newly provided with identification data for identifying an object. The identification data of each battery element220is recorded in association with an identification number assigned to the used battery210before its disassembly.

FIG.7is a flowchart illustrating an example of a procedure of a battery deterioration degree determination system according to this embodiment.FIG.8is a block diagram illustrating an example of a configuration of the management server110used in the battery deterioration degree determination system according to this embodiment. Although not illustrated inFIG.8, the management server110includes a recording part that records data and a data communication part that performs data communication with the outside. The management server110uses a data processing part to perform a data processing operation by executing a program recorded beforehand. Further, an operation program of the management server110need not be recorded in the recording part beforehand but may be downloaded from an external device. Further, similar to the first embodiment illustrated inFIG.5, the management server110of this embodiment is data-communicably connected to the power supply device100via a network.

As illustrated inFIG.8, the management server110has a recording part in which identification data111, historical data112, and diagnosis data113are recorded and a deterioration determination part114that determines deterioration of the battery element220. The deterioration determination part114may be implemented by executing a program by the data processing part of the management server110or implemented by an external device that is data-communicably connected to the management server110via a network. Further, a measurement device that measures the electrical characteristics of the battery element220is provided inside or outside the management server110. The measurement device transmits the result of the measurement to the management server110as measurement data, to thereby provide the measurement function of the deterioration determination part114.

As illustrated inFIG.7, in the battery deterioration degree determination system of this embodiment, the used battery210is removed from the battery using apparatus200in a removing step of step S11. Then, in a usage history data acquisition step of step S12, the historical data of the used battery210recorded in the battery using apparatus200is acquired. The historical data112acquired in the usage history data acquisition step is recorded in the management server110in association with the identification number of the used battery210.

Then, in a disassembly step in Step S13, the used battery210is disassembled, and the battery elements220included in the used battery210are separated individually. At this time, each separated battery element220is provided with identification data111. The identification data111of each battery element220is recorded in the management server110in association with the identification number and historical data112of the used battery210before its disassembly. Accordingly, the identification data111for each battery element220and the identification number and historical data112of the used battery210are associated with each other and recorded in the management server110. This allows each battery element220to be tracked back to the historical data112of the used battery210and the battery using apparatus200prior to the disassembly of the used battery210.

Then, in a module diagnosis step of step S14, a charging operation or a discharging operation is performed on the battery elements220to measure the electrical characteristics of the battery elements220, so that the deterioration determination unit114determines an initial deterioration degree. Here, the electrical characteristics measured in the module diagnosis step corresponds to the first electrical characteristics of the present invention. Further, the initial deterioration degree is the deterioration degree of the used battery210in a first stage of being removed from the battery using apparatus200, which corresponds to the first deterioration degree of the present invention. Further, in a case of measuring the electrical characteristics, it is preferable to add a BMS to each battery element220when each battery element220is not provided with a BMS.

Then, in an individual data recording step of step S15, the initial deterioration degree determined by the deterioration determination part114is included in the diagnosis data113and recorded in the management server110. Further, the historical data112of the used battery210associated with each battery element220is duplicated, and the individual historical data112associated with the identification data111of each battery element220are recorded in the management server110. Here, the diagnosis data113may include, in addition to the initial deterioration degree that is determined, the date and time of the measurement of electrical characteristics, the measurement conditions, and the measurement results. Further, the deterioration determination part114records the diagnosis data113in association with the identification data111and historical data112of the battery element220.

In a module diagnosis step of step S14, in addition to the measured electrical characteristics, the deterioration degree of an initial stage may be determined by referring to the identification data111and the historical data112recorded in the management server110. For example, data such as the number of times of charging or discharging, the travel distance, or the like is acquired from the historical data of the used battery210in the battery using apparatus200, and the relation between these data and the deterioration degree is created beforehand as the table data. Thereby, the deterioration degree is determined by referring to the table data. Further, because the management server110records the historical data112and the diagnosis data113with respect to a vast number of battery elements220, the relation between the historical data112and the diagnosis data113may be analyzed by machine learning based on the vast amount of data. Thereby, the deterioration degree can be determined according to the analysis.

Then, in a grading step of step S16, the battery elements220are classified (classified into classes) according to the deterioration degrees from the diagnosis data113recorded in the management server110. Then, in a reconstruction step of step S17, plural classified battery elements220are combined and accommodated in the accommodation part20to be reconstructed into a regeneration battery. At this time, the battery elements220classified into the same class may be connected in series or in parallel, and the battery elements220classified into different classes may be connected in series or in parallel depending on the required voltage. Further, the total of the chargeable capacity of the reconstructed regeneration battery can also be calculated as the sum of the battery elements220included in the regeneration battery. Here, the configuration of the power supply device100illustrated in the first embodiment can be adopted as that of the regeneration battery,

Then, in a reuse step of step S18, the reconstructed regeneration battery is used to perform a discharging operation by supplying electric current to the various loads91and perform a charging operation from an external electric power supply or the solar panel90. After the reuse step is continued for a predetermined period, the procedure proceeds to step S19.

Then, in a deterioration data acquisition step of step S19, the electrical characteristics of the regeneration battery at the time of the charging operation or the discharging operation are measured by using the deterioration measurement part50of the power supply device100or the deterioration determination part114of the management server110. Here, the electrical characteristics of the regeneration battery correspond to the second electrical characteristics of the present invention. Further, the deterioration measurement part50or the deterioration determination part114updates the historical data112by adding the measured electrical characteristics and the usage history of the regeneration battery until the time of the measurement to the historical data112. Further, the deterioration measurement part50or the deterioration determination part114determines the deterioration degree of the battery element220again based on the measured electrical characteristics and the updated historical data112and updates the diagnosis data113of the management server110by adding the determined deterioration degree to the diagnosis data113. Here, the deterioration degree determined again in the deterioration data acquisition step corresponds to the second deterioration degree of the present invention.

As described above, in this embodiment, the historical data112and the diagnosis data113updated in the deterioration data acquisition step are accumulated in the management server110whenever the regeneration battery is used and are used in determining the deterioration degree of the other battery elements220. Therefore, in the module diagnosis step and the deterioration data acquisition step, the initial deterioration degree is determined by referring to the usage history of the battery using apparatus200, the electrical characteristics at the time of disassembly of the battery elements220, and the usage history of the other regeneration batteries. Accordingly, not only is the electrical characteristics at the time of disassembly of the battery units220used for determining the deterioration degree, but also big data of the usage history and the electrical characteristics chronologically obtained from the time before the disassembly to the time after the reuse are used. Thus, the deterioration degree can be determined with increased accuracy for predicting how much the regeneration battery reconstructed with the battery elements220can be continuously charged or discharged.

Then, in a replacement target determination step of step S20, it is determined whether to replace the battery element220using the method illustrated inFIG.4of the first embodiment. If the battery element220to be the target for replacement does not exist, the procedure proceeds to step S18to continue the reuse step. If it does exist, the procedure proceeds to step S21. In a replacement notification step of step S21, the battery element220to be replaced is notified to the outside of the management server110via the network.

As described above, the battery deterioration degree determination system of this embodiment records the identification data111of the battery element220in association with the historical data112used in the management server110, measures the first electrical characteristic at the time of charging or discharging of the battery element220, and determines the initial deterioration degree based on the measurement result and the historical data112. Further, the deterioration determination part114records the diagnosis data113including the initial deterioration degree in association with the identification data111in the management server110. By determining the deterioration degree based on the electrical characteristics and historical data of the battery element220, the deterioration degree can be determined accurately because not only is the status of the battery element220at the time of measuring the electrical characteristics taken into consideration but also the usage history starting from the time of the manufacture of the battery element220is taken into consideration.

Further, the deterioration determination part114updates the historical data112by measuring the second electrical characteristic at the time of charging or discharging of the battery element220after a lapse of a predetermined period, determines the second deterioration degree based on the measurement result of the second electrical characteristic and the historical data112, and updates the diagnosis data113by adding it with the second deterioration degree. Thus, the deterioration degree can be determined with consideration of the usage history of the reconstructed regeneration battery. Thereby, the deterioration degree can be determined with greater accuracy.

Further, the deterioration determination part114analyzes the relation between the historical data112and the diagnosis data113regarding the plural battery elements220by machine learning and updates the method of determining the initial deterioration degree and the second deterioration degree based on the result of the analysis. Accordingly, the deterioration degree of the battery element220can be determined with greater accuracy by measuring the battery element220removed from the battery using apparatus200, using the reconstructed regeneration battery, and gathering the usage history and the electrical characteristics of the regeneration battery.

The present invention is not limited to the above-described embodiments, and various changes can be made within the scope shown in the claims, and embodiments obtained by appropriately combining the technical means disclosed respectively in the different embodiments are also included in the technical scope of the present invention.

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