JP7658929B2 - Battery Capacity Recovery System - Google Patents

Description

The present invention relates to a battery capacity recovery system.

As background technology in this technical field, the abstract of the following Patent Document 1 states, "A capacity recovery system recovers the capacity of a battery pack of lithium ion secondary batteries mounted on a vehicle. The capacity recovery system includes a capacity recovery device 40, a communication device 340, and a server 300. The capacity recovery device 40 is configured to be capable of executing a recovery process that recovers the capacity of the battery pack 10 by maintaining the SOC of the battery pack 10 at or below a reference value X2. The communication device 340 acquires recovery data P1, P2 including the reference value X2 of the SOC used in the recovery process and the capacity recovery rate R by the recovery process. The server 300 calculates the reference value X2 used in the recovery process for the target vehicle, vehicle 1, using the recovery data P1, P2."

JP 2018-63906 A

However, in the above-mentioned technology, there is a demand for a method for more appropriately restoring the capacity of a secondary battery.
The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a battery capacity recovery system that can appropriately recover the capacity of a secondary battery.

In order to solve the above problem, the battery capacity recovery system of the present invention comprises a battery system including a secondary battery having a plurality of battery cells connected in series and a battery control device that controls the plurality of battery cells, a charger that charges the battery system, a processing device connected to a database unit that stores information about the battery system, and a communication device that is connected to the battery system or the charger and inputs and outputs information between the battery system and the charger. The processing device comprises a data acquisition unit that acquires an operation history including time series data of the cell voltage of the battery cell and time series data of the cell current that is the current flowing through the battery cell from the communication device when the battery system and the charger are connected, a recovery capacity calculation unit that calculates a recovery capacity expectation value, which is an expected value at which capacity can be restored in the secondary battery, based on the operation history, a capacity recovery control unit that outputs a capacity recovery command to the secondary battery via the communication device based on the recovery capacity expectation value, and a notification unit that transmits to a specified terminal device whether the capacity recovery process is being executed or not, or a schedule for the capacity recovery process.

According to the present invention, the capacity of the secondary battery can be appropriately restored.

FIG. 2 is a schematic cross-sectional view of a bipolar battery cell. FIG. 2 is a schematic side view of the electricity storage element. 1 is a block diagram of a battery capacity recovery system according to a first embodiment. FIG. 1 is a block diagram of a computer. FIG. 2 is a block diagram of a battery pack. FIG. 1 is a diagram showing an overview of a material property database. FIG. 2 is a diagram showing an overview of a deterioration prediction database. FIG. 13 is a diagram showing an overview of a capacity recovery database. FIG. 2 is a diagram showing an overview of a safety judgment database. 13 is a flowchart of a diagnostic mode processing routine. FIG. 4 is a diagram showing an example of potential curve data. FIG. 4 is an enlarged view of a main portion of negative electrode potential curve data. 2 is a block diagram showing the relationship between the main parts of a server machine and a database unit. 11 is a flowchart (1/2) of a capacity recovery process routine in the first embodiment. 13 is a flowchart (2/2) of a capacity recovery process routine in the first embodiment. FIG. 11 is a diagram showing an example of a distribution state of discharge amount data during a capacity recovery process. FIG. 13 is a diagram illustrating an example of a distribution state of recovery upper limit capacity data. FIG. 5 is a block diagram of a battery capacity recovery system according to a second embodiment. 10 is a flowchart of a diagnosis process in a second embodiment. 10 is a flowchart of a capacity recovery process routine in the second embodiment.

[Battery cell structure]
First, with reference to Figs. 1 and 2, a structural example of a bipolar battery cell applicable to the embodiment will be described.
FIG. 1 is a schematic cross-sectional view of a bipolar battery cell 10.
In Fig. 1, a battery cell 10 is a lithium ion battery cell, and includes an electricity storage element 1, a positive electrode terminal 2, a negative electrode terminal 3, and an exterior material 6. A separator 5 is included in the electricity storage element 1. The exterior material 6 is made of a laminate film or a similar material. Note that the shape of the battery cell 10 is not limited to a rectangular shape as shown in Fig. 1, and may be a cylindrical shape (not shown).

FIG. 2 is a schematic side view of the electricity storage element 1. As shown in FIG.
As shown in FIG. 2, in the electric storage element 1, a plurality of positive electrodes 12 and a plurality of negative electrodes 13 are alternately stacked with a separator 5 interposed therebetween. The electric storage element 1 shown in FIG. 1 corresponds to the area where the positive electrodes 12 and the negative electrodes 13 appear to overlap. The structure of the electric storage element 1 is not limited to the stacked type as shown in FIG. 2. That is, although not shown, the electric storage element 1 may be a wound type in which the positive electrodes 12 and the negative electrodes 13 are stacked so as to face each other with the separator 5 therebetween and then wound. The electric storage element 1 further contains an electrolyte (not shown), and the electrolyte is impregnated into the micropores of the positive electrodes 12, the negative electrodes 13, the separator 5, and the like. For example, polypropylene can be used as the separator 5. However, in addition to polypropylene, a microporous film or nonwoven fabric made of polyolefin such as polyethylene can also be used as the separator 5.

The positive electrode 12 and the negative electrode 13 are each made by applying a mixture of an appropriate electrode active material, conductive agent, binder, etc. to a current collector foil of an appropriate metal. Metal tabs are connected to the current collector foils of the positive electrode 12 and the negative electrode 13. The exterior material 6 is sealed so that only the tabs are exposed to the outside of the exterior material 6. As a result, the tabs become the positive electrode terminal 2 and the negative electrode terminal 3 in Figure 1. Hereinafter, the potentials of the positive electrode 12 and the negative electrode 13 are referred to as the positive electrode potential Ep and the negative electrode potential En. The difference between the two, i.e., "Ep-En", is the voltage between the positive electrode terminal 2 and the negative electrode terminal 3, and this is referred to as the cell voltage V.

The current collector foil of the positive electrode 12 may be made of aluminum foil having a thickness of 10 to 100 μm, aluminum perforated foil having a thickness of 10 to 100 μm and a pore size of 0.1 to 10 mm, expanded metal, or foamed metal plate. In addition to aluminum, the current collector foil may also be made of stainless steel or titanium. In this embodiment, any current collector may be used without being limited by material, shape, manufacturing method, or the like.

The electrode active material of the positive electrode 12 is preferably one that contains a reactive species therein. The reactive species of a lithium ion battery is lithium ions. In this case, the electrode active material of the positive electrode 12 contains a lithium-containing compound that can reversibly insert and remove lithium ions. The type of electrode active material of the positive electrode 12 is not particularly limited, and examples thereof include lithium cobalt oxide, lithium manganese-substituted cobalt oxide, lithium manganate, lithium nickel oxide, lithium transition metal phosphate such as olivine-type lithium iron phosphate, and Li _w Ni _x Co _y Mn _z O ₂ (wherein w, x, y, and z are 0 or positive values). The electrode active material of the positive electrode 12 may contain one or more of the above materials.

The current collector foil of the negative electrode 13 may be copper foil having a thickness of 10 to 100 μm, copper perforated foil having a thickness of 10 to 100 μm and a pore size of 0.1 to 10 mm, expanded metal, or foamed metal plate. In addition to copper, stainless steel, titanium, and other materials may also be used for the current collector foil. In this embodiment, any current collector can be used without being limited by material, shape, manufacturing method, etc.

The electrode active material of the negative electrode 13 contains a material capable of reversibly inserting and detaching lithium ions. The type of electrode active material of the negative electrode 13 is not particularly limited, but examples thereof include natural graphite, composite carbonaceous materials formed by forming a coating on natural graphite by a dry CVD method or a wet spray method, artificial graphite produced by firing resin materials such as epoxy and phenol, or pitch-based materials obtained from petroleum or coal, silicon (Si), graphite mixed with silicon, non-graphitizable carbon materials, lithium titanate Li ₄ Ti ₅ O ₁₂ , and niobium titanium oxide TiNb ₂ O _7. The negative electrode active material may contain one or more of the above materials.

The storage element 1 is impregnated with an electrolyte. There are no particular limitations on the electrolyte, but in the case of a lithium ion battery, aprotic organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), methyl propyl carbonate (MPC), and ethyl propyl carbonate (EPC) can be used.

The electrolyte may also be a solution of a lithium salt such as lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium iodide, lithium chloride, lithium bromide, LiB[ _OCOCF3 ] ₄ , LiB _[ OCOCF2CF3]4, _LiPF4 ( _CF3 ) ₂ , LiN( _SO2CF3 ) ₂ , LiN( _SO2CF2CF3 ) ₂ , or a mixed _lithium salt of _two or more of these, dissolved in a solvent of _{a mixed} organic compound of two or more _of these.

A solid electrolyte may be used instead of the electrolytic solution. There are no particular limitations on the solid electrolyte, but examples include ion-conductive polymers such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, polyhexafluoropropylene, and polyethylene oxide. When such solid polymer electrolytes are used, the separator 5 can be omitted.

[First embodiment]
Configuration of the First Embodiment
FIG. 3A is a block diagram of a battery capacity recovery system 100 according to a first embodiment.
The battery capacity recovery system 100 includes a communication module 52 (communication device), a charger 54, a battery system 56, a user terminal 60 (terminal device), a server machine 70 (processing device), and a database unit 80.

The user terminal 60 is, for example, a portable information terminal.
The server machine 70 includes a data acquisition unit 71, a recovery upper limit capacity calculation unit 72 (recovery capacity calculation unit), a recoverable capacity calculation unit 74, an operation history/deterioration rate validity determination unit 75, a capacity recovery control unit 76, an alarm unit 77, a capacity recovery evaluation unit 78, and a capacity recovery amount prediction correction unit 79.

The database section 80 includes a material property database 82, a deterioration prediction database 84, a capacity recovery database 86, and a safety judgment database 88 (relationship storage database).
The database unit 80 in this embodiment does not simply store data, but also has a function of outputting predicted values for data that has not been stored by performing machine learning, interpolation processing, and the like.

When the battery system 56 and the charger 54 are connected, the data acquisition unit 71 in the server machine 70 acquires operation history data including time series data of the cell voltage V and cell current I of each battery cell 10 from the communication module 52.
Furthermore, the recovery upper limit capacity calculation unit 72 calculates recovery upper limit capacity expectation value data, which is an expectation value for the capacity recoverable in the battery pack 20 (secondary battery, see FIG. 4), based on the operation history data.

The function of the recoverable capacity calculation unit 74 will be described later.
The operation history/deterioration rate validity determination unit 75 determines whether or not the operation history data Dn11 and the deterioration rate data Dn12 of the target battery pack 20 have a predetermined validity.
The capacity recovery control unit 76 outputs a capacity recovery command to the battery pack 20 via the communication module 52 based on the recovery upper limit capacity expectation value data, to instruct the battery pack 20 to execute a capacity recovery process (S22, S24 described below).

The notification unit 77 transmits to the user terminal 60 whether or not the capacity recovery process (S22, S24 described below) is being executed, or a schedule for the capacity recovery process (S22, S24). Furthermore, the notification unit 77 notifies the user terminal 60 of the recovery upper limit capacity expected value data, the capacity recovery actual value, and the next capacity recovery time.

The capacity recovery evaluation unit 78 determines whether the capacity recovery process (S22, S24) was successful based on the contents of the safety judgment database 88, the discharge amount data after the capacity recovery process (S22, S24) was performed, and the capacity recovery performance value data.

Fig. 3B is a block diagram of a computer 980. Each of the server machine 70, the charger 54, the user terminal 60 and the database unit 80 shown in Fig. 3A includes one or more computers 980 shown in Fig. 3B.
3B, a computer 980 includes a CPU 981, a storage unit 982, a communication I/F (interface) 983, an input/output I/F 984, and a media I/F 985. Here, the storage unit 982 includes a RAM 982a, a ROM 982b, and a HDD 982c.

The communication I/F 983 is connected to a communication circuit 986. The input/output I/F 984 is connected to an input/output device 987. The media I/F 985 reads and writes data from a recording medium 988. The ROM 982b stores control programs executed by the CPU, various data, etc. The CPU 981 realizes various functions by executing application programs loaded into the RAM 982a. The interior of the server machine 70 shown in Figure 3A above is a block diagram showing the functions realized by application programs, etc.

Fig. 4 is a block diagram of the battery pack 20. The battery system 56 shown in Fig. 3A includes this battery pack 20.
In FIG. 4 , the battery pack 20 includes a plurality of battery cells 10 connected in series, a plurality of cell controllers 22, a plurality of voltage detection lines 23, a plurality of thermocouples 24, a battery control device 25, communication lines 26, 28, and a current sensor 27.

The cell controller 22 is connected to the battery cells 10 via a voltage detection line 23, and detects the state of the battery cells 10, i.e., the cell voltage V (see FIG. 1) and temperature. The multiple cell controllers 22 are also connected to the battery control device 25 via a communication line 26. The current sensor 27 detects the cell current I flowing through the battery cells 10 connected in series, and notifies the battery control device 25 of the cell current I. The battery control device 25 obtains the state of the multiple battery cells 10 from the multiple cell controllers 22.

The battery control device 25 calculates the SOC (state of charge) of the battery pack 20 and other data based on the cell current I obtained from the current sensor 27 and the states of the multiple battery cells 10 obtained from the cell controller 22. The battery control device 25 then communicates the calculated SOC and other data to a higher-level device (e.g., the charger 54 or server machine 70 in FIG. 3A) via the communication line 28.

FIG. 5 is a diagram showing an overview of the material characteristics database 82.
5, the material property database 82 stores deterioration state data D10 and potential curve data D50 in association with each other. Here, the deterioration state data D10 includes operation history data D11 (operation history) and deterioration rate data D12 (deterioration rate).

The operation history data D11 is time-series data such as the SOC, temperature, cell voltage V, cell current I, and voltage drop rate of each battery cell 10. The deterioration rate data D12 includes the capacity deterioration rate SOHQ of the battery pack 20, the resistance deterioration rate SOHR of the battery pack 20, the capacity deterioration rate SOHQ of each battery cell 10, and the resistance deterioration rate SOHR of each battery cell 10.

The potential curve data D50 also includes positive electrode potential curve data D54 and negative electrode potential curve data D56. Here, the positive electrode potential curve data D54 indicates the characteristics of the positive electrode potential Ep (see FIG. 1) relative to the amount of discharge or charge of the battery cell 10. Furthermore, the negative electrode potential curve data D56 indicates the characteristics of the negative electrode potential En (see FIG. 1) relative to the amount of discharge or charge of the battery cell 10.

FIG. 6 is a diagram showing an overview of the deterioration prediction database 84. As shown in FIG.
6, the deterioration prediction database 84 stores the above-mentioned operation history data D11 and the above-mentioned deterioration rate data D12 for various battery packs 20 (see FIG. 4) in association with each other.

FIG. 7 is a diagram showing an overview of the capacity recovery database 86. As shown in FIG.
7, the capacity recovery database 86 stores, in association with each other, degradation state data D10, recovery upper limit capacity data D20, and capacity recovery performance value data D24. Here, the recovery upper limit capacity data D20 is data indicating the upper limit of the capacity that can be recovered by the capacity recovery process in the battery pack 20 (see FIG. 4).

The capacity recovery rate data D22 is the result of dividing the capacity recovery actual value data D24 by the recovery upper limit capacity data D20. Here, the capacity recovery actual value data D24 is data indicating the actual value of the capacity recovered by the capacity recovery process. The capacity recovery database 86 also does not include data for cases where the determination result in the above-mentioned capacity recovery evaluation unit 78 is negative, i.e., where the capacity recovery process has failed.

FIG. 8 is a diagram showing an overview of the safety determination database 88. As shown in FIG.
8, the safety determination database 88 stores discharge amount data D30, capacity recovery result value data D24, and safety determination data D32 in association with each other. Here, the discharge amount data D30 is data indicating the discharge amount in the capacity recovery process.

The safety judgment data D32 is data indicating the degree of safety when the capacity recovery process is executed under the conditions for the corresponding discharge amount data D30 and capacity recovery actual value data D24. The safety judgment database 88 also does not include data for cases where the judgment result in the capacity recovery evaluation unit 78 described above is negative, i.e., when the capacity recovery process has failed.

<Operation of the First Embodiment>
Next, the operation of this embodiment will be described.
FIG. 9 is a flow chart of the diagnostic mode processing routine.
This routine is started when a command to execute a diagnostic mode process is output from the user terminal 60 (see FIG. 3A).
First, when the process in the charger 54 proceeds to step S2, the charger 54 executes a charging process. The charging process in step S2 is an intermittent charging process or a charging process at a low current. In other words, it is preferable that the charging process includes a timing at which the cell voltage V can be regarded as "cell voltage V = OCV (Open Circuit Voltage)".

Next, when the process proceeds to step S4 in the charger 54, the charger 54 transmits the operation history data Dn11 obtained in the previous step S2 to the server machine 70. Here, the operation history data Dn11 includes data such as the cell current I (see FIG. 5), cell voltage V (see FIG. 1), voltage drop rate, and temperature, similar to the operation history data D11 (see FIG. 6). However, the operation history data Dn11 was obtained in the previous step S2, and is generally not yet included in the deterioration prediction database 84.

Meanwhile, in step S8, the server machine 70 receives the operation history data Dn11 from the charger 54. Next, when the process in the server machine 70 proceeds to step S10, the recovery upper limit capacity calculation unit 72 of the server machine 70 refers to the material property database 82 and the deterioration prediction database 84. That is, the recovery upper limit capacity calculation unit 72 reads out the operation history data D11 adjacent to the operation history data Dn11 currently acquired from the charger 54 and the corresponding deterioration rate data D12 from the deterioration prediction database 84.

The upper recovery capacity calculation unit 72 then performs an interpolation process on the read data to calculate the deterioration rate data Dn12 (not shown) corresponding to the current operation history data Dn11. This results in the deterioration state data Dn10 (not shown) that combines the operation history data Dn11 and the deterioration rate data Dn12. Next, the upper recovery capacity calculation unit 72 refers to the material properties database 82 and obtains the potential curve data Dn50 that corresponds to the deterioration state data Dn10.

First, FIG. 10 is a diagram showing an example of the potential curve data Dn50.
In Fig. 10, the potential curve data Dn50 includes corrected positive electrode potential curve data Dn54 and corrected negative electrode potential curve data Dn56 (negative electrode potential curve data). The voltage curve data Vx in the figure is the result of subtracting the corrected negative electrode potential curve data Dn56 from the corrected positive electrode potential curve data Dn54. The vertical axis in Fig. 10 represents voltage and potential. The horizontal axis represents discharge capacity [Ah], with a value of "0" representing a fully charged state and a negative value representing an overcharged state.

The recovery upper limit capacity calculation unit 72 acquires the potential curve data Dn50 as follows. First, the material property database 82 stores the positive electrode potential curve data D54 and the negative electrode potential curve data D56. These have shapes that are similar to the corrected positive electrode potential curve data Dn54 and the corrected negative electrode potential curve data Dn56 shown in FIG. 10. In addition, the difference between the positive electrode potential curve data D54 and the negative electrode potential curve data D56 provides the virtual characteristics of the cell voltage V (see FIG. 1).

This hypothetical characteristic has a shape similar to the voltage curve data Vx shown in FIG. 10, but generally deviates from the voltage curve data Vx. Therefore, the upper recovery capacity calculation unit 72 shifts and expands the positive electrode potential curve data D54 and the negative electrode potential curve data D56 in the horizontal axis direction to determine the shift amount and expansion rate at which the hypothetical characteristic of the cell voltage V (see FIG. 1) is most similar to the voltage curve data Vx.

Then, the positive electrode potential curve data D54 and the negative electrode potential curve data D56 are transformed based on the calculated shift amount and expansion/contraction rate to become the corrected positive electrode potential curve data Dn54 and the corrected negative electrode potential curve data Dn56 shown in FIG. 10.

Returning to FIG. 9, when the process proceeds to step S12, the recovery upper limit capacity calculation unit 72 calculates the recovery upper limit capacity expected value data Dn20 based on the potential curve data Dn50. The details of the process in step S12 will be described again with reference to FIG. 10 and FIG. 11.

10, the negative electrode potential En when the SOC is 0% can be obtained based on the corrected negative electrode potential curve data Dn 56. The negative electrode potential En at this time is called En0 (charging information).
FIG. 11 is an enlarged view of a main portion of the corrected negative electrode potential curve data Dn56 shown in FIG.
The discharge capacity at the discharge end in the corrected negative electrode potential curve data Dn56 is denoted by Qe. Then, the difference between the discharge capacity at the negative electrode potential En0 (charging information), i.e., the discharge capacity at SOC=0%, and the discharge capacity Qe corresponds to the upper limit recoverable capacity and becomes the recovery upper limit capacity expected value data Dn20 of the battery cell 10.

Returning to FIG. 9, when the process proceeds to step S 14 , the recoverable capacity calculation unit 74 refers to the capacity recovery database 86 .
As shown in FIG. 7, the capacity restoration database 86 stores degradation state data D10, restoration upper limit capacity data D20, and capacity restoration result value data D24 in association with each other.
Therefore, the capacity recovery database 86 outputs the capacity recovery expectation value data Dn24 corresponding to the current recovery upper limit capacity expectation value data Dn20 (see FIG. 11) and the current degradation state data Dn10.

Next, when the process proceeds to step S16, the recoverable capacity calculation unit 74 calculates the capacity recovery rate expectation data Dn22 by dividing the capacity recovery expectation data Dn24 by the recovery upper limit capacity expectation data Dn20.

Next, when the process proceeds to step S18, the recoverable capacity calculation unit 74 transmits the calculated capacity recovery rate expected value data Dn22 and capacity recovery expected value data Dn24 to the user terminal 60 (see FIG. 3A). This allows the user to understand what level of capacity recovery rate can be expected if a capacity recovery process is performed on the battery system 56 (see FIG. 1). Of the above-mentioned processes, steps S2 to S16 are referred to as "diagnosis mode process S100."

FIG. 12 is a block diagram showing the relationship between the main parts of the server machine 70 and the database unit 80. As shown in FIG.
The material property database 82 outputs potential curve data Dn50 based on the degradation state data Dn10, i.e., the operation history data Dn11 and the degradation rate data Dn12. The recovery upper limit capacity calculation unit 72 outputs recovery upper limit capacity expectation value data Dn20 based on the potential curve data Dn50, the cell voltage V, and the cell current I. The capacity recovery database 86 outputs capacity recovery expectation value data Dn24 based on the degradation state data Dn10 and the recovery upper limit capacity expectation value data Dn20. In addition, the recoverable capacity calculation unit 74 outputs capacity recovery rate expectation value data Dn22 by dividing the capacity recovery expectation value data Dn24 by the recovery upper limit capacity expectation value data Dn20.

13 and 14 are flow charts of a capacity recovery processing routine.
This routine is started when a command to execute capacity recovery processing is output from the user terminal 60 .
First, in step S21 of Fig. 13, when the charger 54 is connected to the battery system 56, the charger 54 notifies the server machine 70 of this fact. Next, the charger 54 and the server machine 70 execute the contents of the diagnosis mode process S100 (see Fig. 9).

When the diagnosis mode process S100 ends, the recoverable capacity calculation unit 74 determines whether or not all of the capacity recovery conditions C1, C2, and C3 listed below are satisfied.
C1: The recovery upper limit capacity expectation data Dn20 is equal to or greater than a predetermined value.
C2: The capacity deterioration rate SOHQ of each battery cell 10 included in the deterioration rate data D12 is equal to or lower than a predetermined value.
C3: No abnormal changes were found in the operation history data Dn11.
To further explain the capacity recovery condition C3, the deterioration prediction database 84 (see FIG. 6) records past operation history data D11 and deterioration rate data D12 for each battery cell 10. It is advisable to statistically compare these contents with the currently acquired operation history data Dn11 and deterioration rate data Dn12 to determine whether any abnormal changes have been observed.

If the result of step S32 is "No", the process proceeds to step S36 in the server machine 70. The recoverable capacity calculation unit 74 transmits a message to the user terminal 60 indicating that "capacity recovery processing is not possible", and the process of this routine ends. On the other hand, if the result of step S32 is "Yes", the process proceeds to step S34 in the server machine 70, and the capacity recovery control unit 76 outputs a capacity recovery command SC2 to the charger 54 via the communication module 52.

When the charger 54 receives the capacity recovery command SC2, the process proceeds to step S22 (capacity recovery process). Here, the charger 54 performs CCCV discharge (constant current constant voltage discharge) process for the capacity recovery process until the cell voltage V reaches a predetermined value. Next, when the process proceeds to step S24 in the charger 54, the charger 54 performs intermittent charging or small current charging of the battery pack 20. Next, when the process proceeds to step S24, the charger 54 outputs charging result report data SC4 to the server machine 70, and the process in the charger 54 ends. Here, the charging result report data SC4 is time series data of the cell voltage V, cell current I, temperature, etc. in the discharging process in step S22 and the charging process in step S24.

When the server machine 70 receives the charging result report data SC4, the process proceeds to step S38 (see FIG. 14) in the server machine 70. Here, the capacity recovery evaluation unit 78 calculates the recovery upper limit capacity expected value data Dn20, the discharge amount data Dn30, and the capacity recovery actual value data Dc24 based on the charging result report data SC4.

Next, when the process proceeds to step S40, the capacity recovery evaluation unit 78 reads the capacity recovery database 86 (see FIG. 7). That is, the capacity recovery evaluation unit 78 acquires the past recovery upper limit capacity data D20 and the capacity recovery performance value data D24 stored in the capacity recovery database 86.

Next, when the process proceeds to step S42, the capacity recovery evaluation unit 78 performs a statistical comparison process. That is, the capacity recovery evaluation unit 78 performs a statistical comparison process between the currently acquired recovery upper limit capacity expectation value data Dn20 and the past recovery upper limit capacity data D20, and performs a statistical comparison process between the currently acquired capacity recovery actual value data Dc24 and the past capacity recovery actual value data D24. For example, the capacity recovery evaluation unit 78 calculates the average value and standard deviation of the past recovery upper limit capacity data D20, and compares the calculated average value with the recovery upper limit capacity expectation value data Dn20. Furthermore, the capacity recovery evaluation unit 78 may calculate the average value and standard deviation of the past capacity recovery actual value data D24, and compare the calculated average value with the capacity recovery actual value data Dc24.

Next, when the process proceeds to step S44, it is determined whether or not both the recovery upper capacity expectation data Dn20 and the capacity recovery actual value data Dc24 are valid based on the results of the statistical comparison process (step S42). For example, when the average value of the recovery upper capacity data D20 is Qa and the standard deviation is σa, if the recovery upper capacity expectation data Dn20 is in the range of "Qa±3σa", it can be determined that the recovery upper capacity expectation data Dn20 is valid, and inappropriate otherwise. Similarly, when the average value of the capacity recovery actual value data D24 is Qb and the standard deviation is σb, if the capacity recovery actual value data Dc24 is in the range of "Qb±3σb", it can be determined that the capacity recovery actual value data Dc24 is valid, and inappropriate otherwise.

If the recovery upper capacity expected value data Dn20 or the capacity recovery actual value data Dc24 is invalid, step S44 is judged as "No" and the process proceeds to step S50. Here, the capacity recovery evaluation unit 78 notifies the user terminal 60 of the abnormality, and the process of this routine ends. For example, the capacity recovery evaluation unit 78 may notify the user terminal 60 that "the battery system 56 is abnormal" and that "it is recommended to stop using the battery system 56." The notified content is also displayed on the user terminal 60.

On the other hand, if both the recovery upper capacity expectation data Dn20 and the capacity recovery actual value data Dc24 are valid, the result of step S44 is determined to be "Yes" and the process proceeds to step S46. Here, the capacity recovery evaluation unit 78 updates the contents of the capacity recovery database 86 (see FIG. 7) and the safety judgment database 88 (see FIG. 8) so as to add the recovery upper capacity expectation data Dn20 and the capacity recovery actual value data Dc24.

Next, when the process proceeds to step S48, the capacity recovery evaluation unit 78 transmits to the user terminal 60 a notification that capacity recovery has been completed and the capacity recovery performance value data Dc24, and the process of this routine ends. The user terminal 60 also displays the notified content.

FIG. 15 is a diagram showing an example of a distribution state of the discharge amount data D30 during the capacity recovery process.
In Fig. 15, the horizontal axis represents the discharge amount data D30 during the capacity recovery process, and the vertical axis represents the number of capacity recovery results, i.e., the number of results of capacity recovery. When the standard deviation of the discharge amount data D30 is σc, most of the discharge amount data D30 during the capacity recovery process falls within a range of "±3σb" from the average value (variance = 0). Therefore, if the discharge amount data Dn30 calculated in step S38 (see Fig. 14) exceeds the range of "±3σb", the discharge amount data Dn30 is considered to be invalid.

FIG. 16 is a diagram showing an example of a distribution state of the recovery upper limit capacity data D20.
In Fig. 16, the horizontal axis is the recovery upper limit capacity data D20, and the vertical axis is the number of capacity recovery results, i.e., the number of results of capacity recovery. When the standard deviation of the recovery upper limit capacity data D20 is σa, most of the recovery upper limit capacity data D20 falls within the range of "±3σa" from the average value (variance = 0). Therefore, if the recovery upper limit capacity expectation value data Dn20 calculated in step S38 (see Fig. 14) exceeds the range of "±3σa", the recovery upper limit capacity expectation value data Dn20 is considered to be invalid.

[Second embodiment]
17 is a block diagram of a battery capacity recovery system 120 according to the second embodiment. In the following description, the same reference numerals are used to designate parts corresponding to those in the first embodiment, and the description thereof may be omitted.
The configuration of the battery capacity recovery system 120 is similar to that of the battery capacity recovery system 100 of the first embodiment described above (see FIG. 3A ), but in this embodiment, a charger 58 is provided instead of the charger 54 of the first embodiment. The charger 58 charges the battery system 56 as necessary, but the charger 58 can operate without being controlled by the server machine 70. For example, when the battery system 56 is applied to a hybrid vehicle, the engine and generator of the hybrid vehicle can be considered to be the charger 58. The configuration of the second embodiment other than that described above is similar to that of the first embodiment.

FIG. 18 is a flowchart of the diagnosis process in this embodiment.
First, unlike the communication module 52 of the first embodiment (see FIG. 9 ), the communication module 52 attached to the battery system 56 repeatedly executes the process of step S6 during operation of the battery system 56. Then, in step S6, the communication module 52 acquires the state of the battery system 56 and transmits the resulting operation history data Dn11 to the server machine 70.

In this embodiment, the server machine 70 also refers to the material property database 82 and the deterioration prediction database 84 in step S8 to acquire the potential curve data Dn50. There are various known methods for acquiring the potential curve data Dn50 based on the operation history data Dn11 during normal operation of the battery system 56. In this embodiment, any of these methods may be applied to acquire the potential curve data Dn50. Otherwise, the processing contents of steps S8 to S18 in the server machine 70 are the same as those in the first embodiment (see FIG. 9). Of the above-mentioned processing, the processing of steps S6 and S8 to S16 is referred to as the "operational diagnosis processing S120."

FIG. 19 is a flowchart of a capacity recovery processing routine in this embodiment.
In Fig. 19, the charger 54 and the server machine 70 execute the contents of the operation diagnostic process S120 (see Fig. 18). The process after the operation diagnostic process S120 is the same as that in the first embodiment (see Figs. 13 and 14). That is, after the process of step S34 is completed, when the server machine 70 receives the charging result report data SC4, the process of step S38 (see Fig. 14) and the subsequent processes are executed in the server machine 70.

[Effects of the embodiment]
As described above, according to the first embodiment, the battery capacity recovery system 100 includes a battery system 56 including a secondary battery (20) having a plurality of battery cells 10 connected in series and a battery control device 25 that controls the plurality of battery cells 10, chargers 54, 58 that charge the battery system 56, a processing device (70) connected to a database unit 80 that stores information related to the battery system 56, and a communication device (52) that is connected to the battery system 56 or the chargers 54, 58 and inputs and outputs information between the processing device (70), and when the battery system 56 and the chargers 54, 58 are connected, the processing device (70) receives time-series data of the cell voltage V of the battery cells 10 and The battery cell 10 includes a data acquisition unit 71 that acquires an operation history (Dn11) including time-series data of a cell current I that is a current flowing through the battery cell 10, a recovery capacity calculation unit (72) that calculates a recovery capacity expectation value (Dn20) that is an expectation value for capacity recovery in the secondary battery (20) based on the operation history (Dn11), a capacity recovery control unit 76 that outputs a capacity recovery command SC2 to the secondary battery (20) via a communication device (52) based on the recovery capacity expectation value (Dn20) to execute a capacity recovery process (S22, S24), and a notification unit 77 that transmits to a predetermined terminal device (60) whether the capacity recovery process (S22, S24) is being executed or a schedule for the capacity recovery process (S22, S24). As a result, the recovery capacity expectation value (Dn20), which is an expectation value for capacity recovery in the secondary battery (20), can be calculated and transmitted to the predetermined terminal device (60), so that the capacity of the secondary battery (20) can be appropriately restored.

According to the second embodiment described above, the system includes a battery system 56 including a secondary battery (20) having a plurality of battery cells 10 connected in series and a battery control device 25 that controls the plurality of battery cells 10, a processing device (70) connected to a database unit 80 that stores information related to the battery system 56, and a communication device (52) connected to the battery system 56 and inputting and outputting information between the processing device (70), and the processing device (70) receives from the communication device (52) an operation history (Dn11) including time series data of the cell voltage V of the battery cell 10 and time series data of the cell current I, which is the current flowing through the battery cell 10. The system includes a data acquisition unit 71 that acquires the data of the secondary battery (20), a recovery capacity calculation unit (72) that calculates a recovery capacity expectation value (Dn20) that is an expected value for which the capacity can be restored in the secondary battery (20) based on the operation history (Dn11), a capacity recovery control unit 76 that outputs a capacity recovery command SC2 to the secondary battery (20) via a communication device (52) based on the recovery capacity expectation value (Dn20) to execute a capacity recovery process (S22, S24), and a notification unit 77 that transmits to a specified terminal device (60) whether the capacity recovery process (S22, S24) is being executed or a schedule for the capacity recovery process (S22, S24). This also makes it possible to calculate the recovery capacity expectation value (Dn20), which is an expected value for which the capacity can be restored in the secondary battery (20), and transmit it to the specified terminal device (60), so that the capacity of the secondary battery (20) can be appropriately restored.

The battery cell 10 further includes a positive electrode 12 and a negative electrode 13, and the recovery capacity calculation unit (72) further includes a function for calculating a recovery capacity expectation value (Dn20) based on the charging information (En0), the deterioration rate (D12) of the battery cell 10, and the operation history (Dn11) of the battery cell 10, and more preferably further includes a capacity recovery amount prediction correction unit 79 that corrects the calculation algorithm for the recovery capacity expectation value (Dn20) based on the charging information (En0), the deterioration rate (D12), the operation history (Dn11), and the capacity recovery actual value (Dc24), which is the actual capacity recovery amount in the secondary battery (20). As a result, the capacity recovery amount prediction correction unit 79 can correct the calculation algorithm for the recovery capacity expectation value (Dn20) to an appropriate one.

Moreover, it is more preferable that the charging information (En0) is a value that correlates with the potential of the negative electrode 13 when the SOC of the battery cell 10 is 0%. This makes it possible to determine the potential of the negative electrode 13 when the SOC of the battery cell 10 is 0% based on the charging information (En0).

The processing device (70) further includes an operation history/deterioration rate validity determination unit 75 that determines whether the operation history (Dn11) and the deterioration rate (Dn12) of the target secondary battery (20) have a predetermined validity based on a deterioration prediction database 84 that stores the correspondence between the operation history (D11) and the deterioration rate (D12), and it is more preferable that the capacity recovery control unit 76 prohibits the execution of the capacity recovery process (S22, S24) when the judgment result of the operation history/deterioration rate validity determination unit 75 is negative. This makes it possible to prohibit the execution of the capacity recovery process (S22, S24) when the operation history (Dn11) or the deterioration rate (Dn12) does not have the predetermined validity.

Moreover, it is more preferable that the processing device (70) further includes a capacity recovery evaluation unit 78 that determines (S44) whether the capacity recovery process (S22, S24) has been successful or not based on the contents of a relationship storage database (88) that stores the relationship between the discharge amount data D30 and the capacity recovery actual value data D24, and the relationship between the discharge amount data Dn30 after the capacity recovery process (S22, S24) has been executed and the capacity recovery actual value (Dc24). This allows appropriate determination of whether the capacity recovery process (S22, S24) has been successful or not.

Moreover, it is more preferable that the relationship memory database (88) does not include data for which the determination result in the capacity recovery evaluation unit 78 is negative. This allows data for which the determination result in the capacity recovery evaluation unit 78 is negative to be excluded from the relationship memory database (88).

Moreover, it is more preferable that the capacity recovery evaluation unit 78 further includes a function of referring to the capacity recovery database 86 that stores the relationship between the capacity recovery actual value data D24 and the recovery upper limit capacity data D20, and judging (S44) whether the capacity recovery process (S22, S24) has been successful or not based on the relationship between the recovery capacity expectation value (Dn20) and the capacity recovery actual value (Dc24) after the capacity recovery process (S22, S24) has been completed. This makes it possible to judge whether the capacity recovery process (S22, S24) has been successful or not based on the relationship between the recovery capacity expectation value (Dn20) and the capacity recovery actual value (Dc24).

Moreover, it is more preferable that the capacity recovery database 86 does not include data for which the determination result in the capacity recovery evaluation unit 78 is negative. This allows data for which the determination result in the capacity recovery evaluation unit 78 is negative to be excluded from the capacity recovery database 86.

Moreover, it is even more preferable that the notification unit 77 further includes a function for notifying the terminal device (60) of the expected recovered capacity value (Dn20), the actual capacity recovery value (Dc24), and the next capacity recovery time. This allows the notification unit 77 to notify the terminal device (60) of the expected recovered capacity value (Dn20), the actual capacity recovery value (Dc24), and the next capacity recovery time.

[Modification]
The present invention is not limited to the above-mentioned embodiment, and various modifications are possible. The above-mentioned embodiment is exemplified to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete a part of the configuration of each embodiment, or to add or replace other configurations. In addition, the control lines and information lines shown in the figure show those that are considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary on the product. In reality, it may be considered that almost all the configurations are connected to each other. Possible modifications of the above-mentioned embodiment are, for example, as follows.

(1) The hardware of the user terminal 60, server machine 70, and database unit 80 in the above embodiment can be realized by a general computer, so programs for executing the various processes shown in the above-mentioned flowcharts, etc., may be stored on a storage medium or distributed via a transmission line.

(2) In the above embodiment, the processes shown in the flowcharts and the like are described as software processes using programs, but some or all of them may be replaced with hardware processes using ASICs (Application Specific Integrated Circuits) or FPGAs (Field Programmable Gate Arrays), etc.

10 Battery cell 12 Positive electrode 13 Negative electrode 20 Battery pack (secondary battery)
25 Battery control device 52 Communication module (communication device)
54, 58 Charger 56 Battery system 60 User terminal (terminal device)
70 Server machine (processing device)
71 Data acquisition unit 72 Recovery upper limit capacity calculation unit (recovery capacity calculation unit)
74 Recoverable capacity calculation unit 75 Operation history/deterioration rate validity determination unit 76 Capacity recovery control unit 77 Notification unit 78 Capacity recovery evaluation unit 79 Capacity recovery amount prediction correction unit 80 Database unit 82 Material property database 84 Deterioration prediction database 86 Capacity recovery database 88 Safety determination database (relationship storage database)
100, 120 Battery capacity recovery system I Cell current V Cell voltage D11 Operation history data (operation history)
D12 Deterioration rate data (deterioration rate)
D20 Recovery upper limit capacity data D24 Capacity recovery actual value data D30 Discharge amount data En0 Negative electrode potential (charging information)
SC2 Capacity recovery command Dc24 Capacity recovery performance value data (capacity recovery performance value)
Dn11 Operation history data (operation history)
Dn12 Deterioration rate data (deterioration rate)
Dn20 Recovery upper limit capacity expected value data (recovery capacity expected value)
Dn30 Discharge amount data Dn50 Potential curve data Dn56 Corrected negative electrode potential curve data (negative electrode potential curve data)
Steps S22 and S24 (Capacity recovery process)

Claims (10)

A battery system including a secondary battery having a plurality of battery cells connected in series and a battery control device that controls the plurality of battery cells;
a charger for charging the battery system;
A processing device connected to a database unit that stores information about the battery system;
a communication device connected to the battery system or the charger for inputting and outputting information between the battery system and the processing device,
The processing device includes:
a data acquisition unit that acquires, from the communication device when the battery system and the charger are connected, an operation history including time series data of a cell voltage of the battery cell and time series data of a cell current that is a current flowing through the battery cell;
a recovery capacity calculation unit that calculates a recovery capacity expectation value, which is an expectation value of capacity recovery in the secondary battery, based on the operation history;
a capacity recovery control unit that outputs a capacity recovery command to the secondary battery via the communication device based on the recovery capacity expected value, the capacity recovery command instructing the secondary battery to execute a capacity recovery process;
a notification unit that transmits to a predetermined terminal device whether the capacity recovery process is being executed or not, or a schedule of the capacity recovery process. The battery cell includes a positive electrode and a negative electrode,
the recovery capacity calculation unit further has a function of calculating the recovery capacity expectation value based on charging information, a deterioration rate of the battery cell, and the operation history of the battery cell;
The battery capacity recovery system according to claim 1, further comprising a capacity recovery amount prediction correction unit that corrects a calculation algorithm of the recovered capacity expected value based on the charging information, the deterioration rate, the operation history, and a capacity recovery actual value that is an actual capacity recovery amount in the secondary battery. 3. The battery capacity recovery system according to claim 2, wherein the charging information is a value correlated with a potential of the negative electrode when the SOC of the battery cell is 0%. the processing device further includes an operation history/deterioration rate validity determination unit that determines whether the operation history and the deterioration rate of a target secondary battery have a predetermined validity based on a deterioration prediction database that stores a correspondence relationship between the operation history and the deterioration rate;
4. The battery capacity recovery system according to claim 2, wherein the capacity recovery control unit prohibits execution of the capacity recovery process when a result of the determination by the operation history/deterioration rate validity determination unit is negative. The battery capacity recovery system according to any one of claims 2 to 4, characterized in that the processing device further comprises a capacity recovery evaluation unit that determines whether the capacity recovery process is successful or not based on the contents of a relationship storage database that stores the relationship between discharge amount data and capacity recovery actual value data, and the relationship between the discharge amount data after executing the capacity recovery process and the capacity recovery actual value. 6. The battery capacity recovery system according to claim 5, wherein the relationship storage database does not include data for cases where the result of the determination in the capacity recovery evaluation unit is negative. The capacity recovery evaluation unit is
The battery capacity recovery system according to claim 5 or 6, further comprising a function of referring to a capacity recovery database that stores the relationship between the capacity recovery actual value data and recovery upper limit capacity data, and determining whether the capacity recovery process has been successful or not based on the relationship between the recovered capacity expectation value and the capacity recovery actual value after the capacity recovery process is completed. 8. The battery capacity recovery system according to claim 7, wherein the capacity recovery database does not include data for cases where the determination result in the capacity recovery evaluation unit is negative. A battery system including a secondary battery having a plurality of battery cells connected in series and a battery control device that controls the plurality of battery cells;
A processing device connected to a database unit that stores information about the battery system;
a communication device connected to the battery system for inputting and outputting information between the battery system and the processing device,
The processing device includes a data acquisition unit that acquires an operation history including time series data of a cell voltage of the battery cell and time series data of a cell current that is a current flowing through the battery cell from the communication device; and
a recovery capacity calculation unit that calculates a recovery capacity expectation value, which is an expectation value of capacity recovery in the secondary battery, based on the operation history;
a capacity recovery control unit that outputs a capacity recovery command to the secondary battery via the communication device based on the recovery capacity expected value, the capacity recovery command instructing the secondary battery to execute a capacity recovery process;
a notification unit that transmits to a predetermined terminal device whether the capacity recovery process is being executed or not, or a schedule of the capacity recovery process. The battery capacity recovery system according to any one of claims 2 to 8, characterized in that the notification unit further has a function of notifying the terminal device of the expected recovery capacity value, the actual capacity recovery value, and the next capacity recovery time.

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