Control device, battery performance estimation method, and program

Abstract

To provide a technique which accurately estimates the performance of a battery.SOLUTION: A control device 10 comprises: a voltage measurement section 110 which measures a voltage of a battery; and a battery performance estimation section 120 which estimates the performance of the battery using the measured voltage of the battery. In a case where a difference between a first voltage which is measured before the start of charging and a second voltage which is measured after a lapse of a first time while a state during the charging is in a first state is equal to or less than a reference value, the battery performance estimation section 120 executes first estimation processing for estimating the performance of the battery using at least one of the first voltage and the second voltage. In a case where the difference exceeds the reference value, the battery performance estimation section 120 executes second estimation processing for estimating the performance of the battery using a third voltage which is measured after a charging operation is performed for a second time in a second state where charge power per unit time is larger than that in the first state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a technique for estimating battery performance. [Background technology]

[0002] Rechargeable batteries are used for various purposes. The performance of rechargeable batteries deteriorates depending on the usage conditions and aging. When using rechargeable batteries, it is important to have a technology that can accurately calculate the deterioration state of the battery.

[0003] An example of a technology for improving the accuracy of estimating the deterioration state of a rechargeable / dischargeable battery is disclosed in the following Patent Document 1. Patent Document 1 discloses a technology for estimating the open circuit voltage (OCV) of a rechargeable / dischargeable battery after performing pre-charging for a certain period of time before measuring the deterioration state of the battery, and estimating the performance of the battery using the estimated open circuit voltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-062175 A Summary of the Invention [Problem to be solved by the invention]

[0005] Immediately after the power supply to a battery is stopped, the voltage is not stable for a certain period of time. If the performance of the battery is estimated in such a state, there is a problem that the accuracy of the estimation result obtained is reduced. One example of an object of the present invention is to provide a technology for estimating the performance of a battery with high accuracy. [Means for solving the problem]

[0006] According to one aspect of the present invention, A voltage measuring means for measuring the voltage of the battery; a battery performance estimation means for estimating the performance of the battery using the measured voltage of the battery; Equipped with The battery performance estimation means a first estimation process for estimating the performance of the battery using at least one of a first voltage and the second voltage when a difference between a first voltage measured before the start of charging and a second voltage measured after a first time has elapsed in a first charging state is equal to or less than a reference value; if the difference exceeds the reference value, a second estimation process is executed to estimate the performance of the battery using a third voltage measured after a second hour of charging in a second state in which the charging power per unit time is greater than that in the first state. A controller is provided.

[0007] According to one aspect of the present invention, a voltage measuring means for measuring a voltage of the battery at a first point in time and at a second point in time that is later than the first point in time; a battery performance estimation means for repeatedly performing a charging operation for the battery for a predetermined time and measuring the voltage of the battery until a difference between a first voltage at the first time point and a second voltage at the second time point becomes equal to or less than a reference value, and estimating performance of the battery using at least one of the first voltage and the second voltage when the difference becomes equal to or less than the reference value; A control device is provided comprising:

[0008] According to one aspect of the present invention, At least one computer a voltage measurement process for measuring a battery voltage; a battery performance estimation process for estimating the performance of the battery using the measured voltage of the battery; Run, In the battery performance estimation process, the at least one computer a first estimation process for estimating the performance of the battery using at least one of a first voltage and the second voltage when a difference between a first voltage measured before the start of charging and a second voltage measured after a first time has elapsed in a first charging state is equal to or less than a reference value; if the difference exceeds the reference value, a second estimation process is executed to estimate the performance of the battery using a third voltage measured after a second hour of charging in a second state in which the charging power per unit time is greater than that in the first state. A method for estimating battery performance is provided, the method including:

[0009] According to one aspect of the present invention, At least one computer measuring a voltage of the battery at a first time point and at a second time point that is later than the first time point; repeating a charging operation for a predetermined time on the battery and measuring the voltage of the battery until a difference between a first voltage at the first time point and a second voltage at the second time point becomes equal to or less than a reference value; estimating performance of the battery using at least one of the first voltage and the second voltage when the difference becomes equal to or less than the reference value; A method for estimating battery performance is provided, the method including:

[0010] According to one aspect of the present invention, At least one computer a voltage measuring means for measuring the voltage of the battery; and a battery performance estimation means for estimating the performance of the battery using the measured voltage of the battery; Function as a The battery performance estimation means a first estimation process for estimating the performance of the battery using at least one of a first voltage and the second voltage when a difference between a first voltage measured before the start of charging and a second voltage measured after a first time has elapsed in a first charging state is equal to or less than a reference value; if the difference exceeds the reference value, a second estimation process is executed to estimate the performance of the battery using a third voltage measured after a second hour of charging in a second state in which the charging power per unit time is greater than that in the first state. A program is provided that includes:

[0011] According to one aspect of the present invention, At least one computer a voltage measuring means for measuring a voltage of the battery at a first point in time and at a second point in time that is later than the first point in time; and a battery performance estimation means for repeatedly executing a charging operation for the battery for a predetermined time and measuring the voltage of the battery until a difference between a first voltage at the first time point and a second voltage at the second time point becomes equal to or less than a reference value, and estimating the performance of the battery using at least one of the first voltage and the second voltage when the difference becomes equal to or less than the reference value; A program is provided to function as such. Effect of the Invention

[0012] According to the present invention, the performance of a battery can be estimated with high accuracy. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating an example of a usage environment of a control device according to the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a control device according to the first embodiment. [Diagram 3] FIG. 2 is a diagram illustrating a hardware configuration of an integrated circuit. [Figure 4] 4 is a flowchart for illustrating an example of the operation of the control device according to the first embodiment. [Diagram 5] 4 is a flowchart for illustrating an example of the operation of the control device according to the first embodiment. [Figure 6] 4 is a flowchart for illustrating an example of the operation of the control device according to the first embodiment. [Figure 7] 10 is a flowchart illustrating a process flow in a modified example of the first embodiment. [Figure 8] 10 is a flowchart illustrating a process flow in a modified example of the first embodiment. [Figure 9] FIG. 11 is a diagram illustrating an example of a functional configuration of a control device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all drawings, similar components are given similar reference numerals, and descriptions thereof will be omitted as appropriate. In addition, unless otherwise specified, in each block diagram, each block represents a functional configuration, not a hardware configuration. In addition, the direction of the arrows in the drawings is merely for making the flow of information easier to understand, and does not limit the direction of communication (one-way communication / two-way communication) unless otherwise specified.

[0015] ·overview FIG. 1 is a diagram illustrating an example of a usage environment of a control device 10 according to the present disclosure. In the usage environment illustrated in FIG. 1, a battery unit 20 is attached to an electric product 30. The electric product 30 operates using power supplied from the battery unit 20. When charging the battery unit 20 after the operation of the electric product 30 is completed, that is, after the power supply to the battery unit 20 is stopped, the user of the electric product 30 connects the battery unit 20 to a power supply system 24 via a charging device 22 such as a connection cable for charging. This starts charging the battery unit 20. Note that when charging the battery unit 20, the battery unit 20 does not have to be attached to the electric product 30. That is, the battery unit 20 may be connected to the power supply system 24 via the charging device 22 after being removed from the electric product 30.

[0016] The battery section 20 functions as a power source for the electrically powered product 30. The battery section 20 is usually configured to include multiple cells or one or more battery modules. A cell is the smallest structural unit that functions as a battery on its own. A battery module is a structural unit in which multiple cells are combined and packaged. The battery section 20 may also include a charge / discharge circuit, a protection circuit, a cooling mechanism, etc. (none of which are shown).

[0017] The electrically powered product 30 is not particularly limited as long as it operates completely or partially dependent on the power of the battery unit 20. For example, the electrically powered product 30 is an electric vehicle or a plug-in hybrid vehicle.

[0018] The control device 10 has at least a function of acquiring information about the state of the battery unit 20 until charging of the battery unit 20 is completed, and estimating the performance of the battery unit 20 using the acquired information. In the following description, "information about the voltage of the battery unit 20" is given as a specific example of "information about the state of the battery unit 20", but the "information about the state of the battery unit 20" is not particularly limited as long as it is information that can be used to estimate the performance of the battery unit 20. For example, the "information about the state of the battery unit 20" may instead of or in addition to "information about the current of the battery unit 20". Furthermore, the "information about the state of the battery unit 20" may further include auxiliary information such as the temperature of the battery unit 20 (the internal temperature or the atmospheric temperature of the battery unit 20).

[0019] The control device 10 may also function as a Battery Management System (BMS). Alternatively, the control device 10 may be a device that extends the function of an existing BMS by being attached to the BMS. The control device 10 may also be incorporated into a so-called battery pack as one of its components. In this case, the battery pack includes a charge / discharge circuit, a protection circuit, a cooling mechanism, and the like (none of which are shown) in addition to the control device 10 and the battery unit 20. Alternatively, the control device 10 may be incorporated into a charging device 22 used when charging the battery pack.

[0020] Hereinafter, the control device 10 according to the present disclosure will be described with reference to several embodiments.

[0021] First embodiment 2 is a diagram illustrating a functional configuration of the control device 10 according to the first embodiment. As shown in FIG.

[0022] The voltage measuring section 110 measures, at any timing, the voltage of the battery section 20. For example, the voltage measuring section 110 can measure the open circuit voltage of the battery section 20 at any timing.

[0023] The battery performance estimation unit 120 estimates the performance of the battery unit 20 using the voltage measured by the voltage measurement unit 110. The battery performance estimation unit 120 can estimate, for example, the degree of deterioration of the battery unit 20 as the performance of the battery unit 20. The degree of deterioration of the battery unit 20 is expressed by indices such as State of Charge (SOC) and State of Health (SOH). The battery performance estimation unit 120 is configured to derive at least one of the SOC and SOH of the battery unit 20 using the voltage of the battery unit 20 measured by the voltage measurement unit 110. The operation of the battery performance estimation unit 120 will be described in detail later.

[0024] 3 is a diagram illustrating an example of a hardware configuration of the integrated circuit 40. In this diagram, the voltage measurement unit 110 and the battery performance estimation unit 120 of the control device 10 are implemented using the integrated circuit 40.

[0025] The integrated circuit 40 is, for example, a System On Chip (SoC), and includes a bus 402, a processor 404, a memory 406, a storage device 408, an input / output interface 410, and a network interface 412.

[0026] The bus 402 is a data transmission path for transmitting and receiving data between the processor 404, the memory 406, the storage device 408, the input / output interface 410, and the network interface 412. However, the method of connecting the processor 404 and the like to each other is not limited to a bus connection.

[0027] The processor 404 is an arithmetic processing device implemented using a microprocessor or the like.

[0028] The memory 406 is a main storage device realized using a random access memory (RAM) or the like.

[0029] The storage device 408 is an auxiliary storage device realized using a read only memory (ROM), a flash memory, or the like.

[0030] The input / output interface 410 is an interface for electrically connecting the integrated circuit 40 (control device 10) to an external element. The input / output interface 410 is, for example, a wiring terminal or a wiring connector provided on the substrate of the integrated circuit 40.

[0031] The network interface 412 is an interface for connecting the integrated circuit 40 (control device 10) to a communication network. This communication network includes, for example, a Controller Area Network (CAN). Note that the method for connecting to the communication network via the network interface 412 may be wireless connection or wired connection.

[0032] The storage device 408 stores program modules corresponding to various functions of the control device 10. The storage device 408 stores at least a program module corresponding to the function of the voltage measurement unit 110 described in the present disclosure and a program module corresponding to the function of the battery performance estimation unit 120. The processor 404 expands the program module read from the storage device 408 on the memory 406 and executes it, thereby realizing the function corresponding to the program module. For example, the processor 404 reads the program module corresponding to the voltage measurement unit 110 on the memory 406 and executes it, thereby realizing the function of the voltage measurement unit 110 described in the present disclosure. Also, for example, the processor 404 reads the program module corresponding to the battery performance estimation unit 120 on the memory 406 and executes it, thereby realizing the function of the battery performance estimation unit 120 described in the present disclosure. The operation of the processor 404 is common to the embodiments included in the present disclosure.

[0033] The hardware configuration of the integrated circuit 40 (control device 10) is not limited to the configuration shown in this figure. For example, program modules corresponding to each function of the control device 10 may be stored in the memory 406. In this case, the integrated circuit 40 (control device 10) may not include the storage device 408.

[0034] An example of the operation of the control device 10 according to the first embodiment will be described below with reference to the drawings. Figures 4 to 6 are flowcharts for illustratively explaining the operation of the control device 10 according to the first embodiment.

[0035] Before the process shown in this flowchart is executed, the electrically powered product 30 operates using power supplied from the battery unit 20. While the electrically powered product 30 is operating, the battery unit 20 is energized (discharging). Here, polarization may occur inside the battery unit 20 due to the discharge of the battery unit 20. If polarization occurs inside the battery unit 20, the voltage of the battery unit 20 may not be stable, which may adversely affect the estimation result of the performance of the battery unit 20. The degree of progression of polarization that may occur during discharge varies depending on the usage environment of the battery unit 20. For example, the degree of progression of polarization that may occur during discharge depends on various factors such as the temperature of the battery unit 20 (internal temperature and atmospheric temperature) and the load on the battery unit 20 (amount of current per unit time).

[0036] When the use of the battery unit 20 in the electrically powered product 30 ends, the power supply to the battery unit 20 is stopped (S102). After that, the control device 10 monitors whether the battery unit 20 and the charger are connected (S104). For example, the battery performance estimation unit 120 monitors whether the cable of the charger 22 is connected to a connector unit (not shown) that receives the cable. A known method is used to detect the connection of the cable of the charger 22.

[0037] When the battery unit 20 and the charging device 22 are connected (S104: YES), the battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery unit 20 before charging of the battery unit 20 starts. In response to the instruction, the voltage measurement unit 110 measures the voltage of the battery unit 20 before charging starts, i.e., before charging power starts to be supplied to the battery unit 20 (S106). In the following description, the voltage measured at this timing is referred to as a first voltage V1. The voltage measurement unit 110 transmits the measurement result (first voltage V1) to the battery performance estimation unit 120.

[0038] After the voltage measurement unit 110 measures the first voltage V1, the battery performance estimation unit 120 keeps the charging state of the battery unit 20 in a first state until a predetermined period (first time T1) has elapsed (S108). Here, the first state (first charging state) is a state in which the charging power per unit time is smaller than that during normal charging. Although not particularly limited, the first state is, for example, a state in which charging is temporarily stopped, that is, a state in which the charging power is temporarily zero. It can also be said that charging of the battery unit 20 has not actually started until the first time T1 has elapsed. If charging of the battery unit 20 is not started even though the battery unit 20 is connected to a charging device, there is a risk that the user of the electric driving product 30 in which the battery unit 20 is mounted will feel uncomfortable. Therefore, the battery performance estimation unit 120 is preferably configured to cause a predetermined output unit to output an indication that charging is being performed normally even if substantial charging has not started until the first time T1 has elapsed. The “output unit” is, for example, a display or an indicator (charging lamp) provided on the electrically powered product 30 or the charging device 22.

[0039] Here, the first time T1 is set to, for example, a length of 1 minute or less. As one example, the first time T1 is a fixed value such as "1 minute" and is stored in the storage device 408 or the memory 406. As another example, the first time T1 may be dynamically set according to the usage environment of the battery unit 20 (the temperature during use of the battery unit 20 and the discharge load per unit time of the battery unit 20), etc. In this case, for example, a function for calculating the first time T1 using parameters related to the usage environment as input is prepared in the storage device 408 or the memory 406. The battery performance estimation unit 120 can dynamically calculate the first time T1 using the function.

[0040] After the first time T1 has elapsed, the battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery unit 20. In response to the instruction, the voltage measurement unit 110 measures the voltage of the battery unit 20 again (S110). In the following description, the voltage measured at this timing is referred to as the second voltage V2. The voltage measurement unit 110 transmits the measurement result (second voltage V2) to the battery performance estimation unit 120.

[0041] The battery performance estimation unit 120 calculates the difference between the first voltage V1 obtained as a result of the measurement process in S106 and the second voltage V2 obtained as a result of the measurement process in S110. Then, the battery performance estimation unit 120 judges whether or not the difference satisfies a predetermined criterion (S112). For example, the battery performance estimation unit 120 judges whether or not the absolute value of the difference between the first voltage V1 and the second voltage V2 is equal to or less than a predetermined reference value (threshold value). In this case, the battery performance estimation unit 120 judges that the criterion is satisfied when the absolute value of the difference between the first voltage V1 and the second voltage V2 is equal to or less than the predetermined reference value. Also, in this case, the battery performance estimation unit 120 judges that the criterion is not satisfied when the absolute value of the difference between the first voltage V1 and the second voltage V2 exceeds the predetermined reference value. That is, in the process of S112, the battery performance estimation unit 120 judges whether or not the polarization generated in the battery unit 20 due to discharge is eliminated based on the fluctuation value of the voltage of the battery unit 20 during the predetermined period.

[0042] When the difference between the first voltage V1 and the second voltage V2 meets the standard (S112: YES), the battery performance estimation unit 120 estimates the performance of the battery unit 20 using at least one of the first voltage V1 and the second voltage V2. For example, when the difference between the first voltage V1 and the second voltage V2 is equal to or less than the standard value, the battery performance estimation unit 120 acquires first information to be used for measuring the performance of the battery unit 20 using at least one of the first voltage V1 and the second voltage V2 (S114). As a more specific example, the battery performance estimation unit 120 estimates the State of Charge (SOC at the start of charging) of the battery unit 20 using the first voltage V1, the second voltage V2, or the average value of the first voltage V1 and the second voltage V2. Then, the battery performance estimation unit 120 acquires the SOC at the start of charging estimated for the battery unit 20 as the first information for performance estimation. The relationship between the voltage and the SOC depends on the material of the battery module 20, and can basically be defined as correlated information. Therefore, the battery performance estimation unit 120 can estimate the SOC of the battery module 20 by using the first voltage V1, the second voltage V2, or the average value of the first voltage V1 and the second voltage V2, or the like.

[0043] When the first information for performance estimation is acquired, the process shown in the flowchart of FIG. 6 is executed. First, the battery performance estimation unit 120 controls the charger 22 to start normal charging (charging at rated power) for the battery unit 20 (S122). After that, the battery performance estimation unit 120 waits until the charging of the battery unit 20 is completed (S124: NO). The charging of the battery unit 20 is completed, for example, when the battery unit 20 is in a predetermined state, or when the connection between the battery unit 20 and the charger 22 is released. The "predetermined state" is, for example, a fully charged state. The battery performance estimation unit 120 acquires the capacity accumulated (increased) in the battery unit 20 during the charging period, and stores it in the memory 406 or the storage device 408. The battery performance estimation unit 120 can acquire the capacity accumulated (increased) in the battery unit 20 during the charging period, for example, by integrating the charging current measured successively during the charging period. The capacity accumulated (increased) in the battery module 20 during the charging period is used in the process of calculating the deterioration degree of the battery module 20. The process of calculating the deterioration degree of the battery module 20 will be described later in detail.

[0044] When charging of the battery module 20 is completed (S124: YES), the battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery module 20. In response to this instruction, the voltage measurement unit 110 measures the voltage after charging is completed (S126). In the following description, the voltage measured at this timing is referred to as the charging completion voltage V E The voltage measurement unit 110 outputs the measurement result (the charging end voltage V E ) to the battery performance estimation unit 120. The battery performance estimation unit 120 preferably waits a certain period of time (e.g., 1 to 3 minutes) after the end of charging, and then transmits the end-of-charging voltage V E In this case, the voltage measurement unit 110 instructs the voltage measurement unit 110 to measure the charging end voltage V E can be measured.

[0045] Charge end voltage V EWhen the charge end voltage V measured by the voltage measurement unit 110 is measured, the battery performance estimation unit 120 acquires second information to be used for performance measurement of the battery unit 20 (S128). E The battery performance estimation unit 120 estimates the State of Charge (SOC after charging is completed) of the battery unit 20 using the above. The battery performance estimation unit 120 can estimate the SOC of the battery unit 20 after charging is completed by the same process as when charging is started. The battery performance estimation unit 120 then calculates an index indicating the degree of deterioration of the battery unit 20, specifically, a State of Health (SOH), based on the estimated value of the SOC of the battery unit 20 at the start of charging, the estimated value of the SOC of the battery unit 20 after charging is completed, and the capacity accumulated in the battery unit 20 during the charging period. A specific method of calculating the SOH will be described later. The process of estimating the performance of the battery unit 20 when the difference between the first voltage V1 and the second voltage V2 satisfies the standard (the processes of S114 and S122 to S128) described above will be referred to as the "first estimation process" in the following description.

[0046] Returning to the branching process of S112 in Fig. 4, a case where the difference between the first voltage V1 and the second voltage V2 does not satisfy the criterion means that the polarization generated inside the battery module 20 due to the discharge of the battery module 20 has not been sufficiently eliminated. In such a case (S112: NO), the battery performance estimation unit 120 executes a further process (e.g., Fig. 5) to stabilize the voltage of the battery module 20, that is, to eliminate the polarization generated inside the battery module 20 due to the discharge, instead of the first estimation process described above.

[0047] In the flowchart of FIG. 5, the battery performance estimation unit 120 controls the charger 22 to perform a charging operation. Specifically, the battery performance estimation unit 120 causes the charger 22 to perform a charging operation until a predetermined period (second time T2) has elapsed while keeping the charging state of the battery unit 20 in the second state (S116). Here, the second state (second charging state) is a state in which the charging power per unit time is greater than that in the first state. As a specific example, the second state is, for example, a state in which charging is performed at the rated power of the charger 22. The charging rate in the second state is a magnitude that does not cause polarization during charging to progress too much, for example, a charging rate of 0.1C or less. By charging the battery unit 20 with normal power, moderate polarization occurs inside the battery unit 20 in the direction opposite to that during discharging. As a result, the polarization during discharging is eliminated faster than if the battery unit 20 was left alone.

[0048] Here, the second time T2 is preferably set within a range of 10 to 20 minutes. Here, the second time T2 is a fixed value such as "15 minutes" and is stored in, for example, the storage device 408 or the memory 406. Also, the second time T2 may be set using a function that inputs parameters related to the usage environment of the battery unit 20, as described for the first time T1. Such a function for dynamically calculating the second time T2 is prepared in, for example, the storage device 408 or the memory 406. The battery performance estimation unit 120 can dynamically calculate the second time T2 using the function. Note that, when the first time T1 and the second time T2 are compared, the first time T1 is significantly shorter than the second time T2. This is because extending the period of the first time T1, that is, the period during which substantial charging is not performed, is undesirable in terms of time efficiency of charging.

[0049] After the second time T2 has elapsed, the battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery unit 20. In response to the instruction, the voltage measurement unit 110 measures the voltage of the battery unit 20 again (S118). In the following description, the voltage measured at this timing is referred to as a third voltage V3. The voltage measurement unit 110 transmits the measurement result (third voltage V3) to the battery performance estimation unit 120.

[0050] When the third voltage V3 is measured, the battery performance estimation unit 120 uses the third voltage V3 to obtain first information for estimating the performance of the battery unit 20 (S120). This process is similar to the process described in S116, except that the third voltage V3 is used. The battery performance estimation unit 120 estimates the SOC of the battery unit 20 from the third voltage V3 based on the relationship between voltage and SOC. The battery performance estimation unit 120 obtains the SOC of the battery unit 20 estimated in this manner as the first information.

[0051] The process of estimating the performance of the battery module 20, which is executed by the battery performance estimation unit 120 after the first information for performance estimation is acquired based on the third voltage V3, is as described with reference to Fig. 6. The process of estimating the performance of the battery module 20 (the process of S116 to S128) which is executed when the difference between the first voltage V1 and the second voltage V2 does not satisfy the criterion as described above, is also referred to as the "second estimation process" in the following description.

[0052] ·SOH calculation method The battery performance estimation unit 120 estimates the SOH of the battery unit 20 using first information for performance estimation (SOC of the battery unit 20 at the start of normal charging), second information for performance estimation (SOC of the battery unit 20 at the end of normal charging), and the capacity accumulated during the normal charging period. Specifically, the battery performance estimation unit 120 estimates the SOH of the battery unit 20 using the following formula.

number

[0053] For example, assume that the capacity accumulated during normal charging is 40 Ah, the SOC indicated in the first state is 50%, the SOC indicated in the second state is 100%, and the capacity of battery module 20 in the initial state is 100 Ah. In this case, battery performance estimation unit 120 can calculate the value of 80% as the SOH of battery module 20 using the above-mentioned formula.

[0054] The above-mentioned formula is recorded in advance in, for example, the memory 406 or the storage device 408. The battery performance estimation unit 120 can estimate the SOH of the battery unit 20 by reading out the formula and using it in calculations.

[0055] The operation and effect of the control device 10 according to the first embodiment will be illustrated. The two SOCs used in the formula for calculating the SOH described above are both estimated from the voltage of the battery unit 20 that is actually measured. Therefore, the accuracy of estimating the SOC is directly linked to the accuracy of estimating the SOH. The control device 10 according to the present disclosure estimates the SOC of the battery unit 20 using the voltage of the battery unit 20 at a stage where the polarization caused inside the battery unit 20 by discharging is eliminated to a certain extent. In particular, when the difference between the above-mentioned first voltage V1 and the second voltage V2 does not satisfy the criterion, the battery performance estimation unit 120 executes a charging operation in the second state of charge (for example, a charging operation at a rated power) until a predetermined second time T2 has elapsed. Then, the battery performance estimation unit 120 measures the third voltage V3 at a stage after the charging operation in the second state of charge has been executed until the second time T2 has elapsed. By performing such a process, the polarization caused inside the battery unit 20 by discharging can be alleviated. As a result, the accuracy of estimating the SOC of the battery module 20, and therefore the accuracy of estimating the SOH of the battery module 20, is improved.

[0056] First Modification of the First Embodiment The process described using the flowchart in Fig. 5 may be further modified, for example, as shown in Fig. 7. Fig. 7 is a flowchart illustrating a process flow in a modified example of the first embodiment. The flowchart illustrated in Fig. 7 includes step S202 in addition to the process illustrated in Fig. 5. The following mainly describes the new step S202.

[0057] After the process of S116 is completed, that is, after the charging operation in the second charging state for the second time T2 is completed, the battery performance estimation unit 120 stops charging the battery unit 20 until a predetermined third time T3 has elapsed (S204). That is, the battery performance estimation unit 120 provides a predetermined interval from the time when the charging operation in the second charging state is completed. The battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery unit 20 when the third time T3 has elapsed since the charging of the battery unit 20 was stopped. In response to this instruction, the voltage measurement unit 110 measures the voltage of the battery unit 20 (third voltage V3) (S118).

[0058] Here, the third time T3 is preferably set to be approximately the same length as the first time T1 from the viewpoint of time efficiency of charging. For example, the third time T3 is set to be within 1 to 3 minutes. As an example, the third time T3 is a fixed value such as "3 minutes" and is stored in the storage device 408 or the memory 406. As another example, the third time T3 may be set using a function that inputs parameters related to the usage environment of the battery unit 20, as described for the first time T1 and the second time T2. Such a function for dynamically calculating the third time T3 is prepared in, for example, the storage device 408 or the memory 406. The battery performance estimation unit 120 can dynamically calculate the third time T3 using the function.

[0059] According to this modification, after the charging operation in the second state (e.g., charging operation at rated power) is performed, a predetermined interval is provided before the voltage of the battery module 20 (third voltage V3) is measured. This allows the third voltage V3 to be measured in a stable state of the voltage of the battery module 20. As a result, it is expected that the accuracy of estimating the SOC of the battery module 20, and therefore the accuracy of estimating the SOH of the battery module 20, can be further improved.

[0060] Second Modification of the First Embodiment The process described using the flowchart in Fig. 5 may be further modified, for example, as shown in Fig. 8. Fig. 8 is a flowchart illustrating a process flow in a modified example of the first embodiment. The flowchart illustrated in Fig. 8 includes steps S302 to S306 in addition to the process illustrated in Fig. 5. The following mainly describes the new steps S302 to S306.

[0061] 8, the battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery unit 20 when the second time T2 has elapsed. In response to this instruction, the voltage measurement unit 110 measures the voltage of the battery unit 20 (S302). In the following description, the voltage measured at this timing is referred to as a fourth voltage V4. The voltage measurement unit 110 transmits the measurement result (fourth voltage V4) to the battery performance estimation unit 120.

[0062] After the fourth voltage V4 is measured, the battery performance estimation unit 120 stops charging the battery unit 20 until a predetermined third time T3 has elapsed (S304), as in the first modified example. That is, the battery performance estimation unit 120 provides a predetermined interval from the time when the charging operation in the second charging state is completed. The battery performance estimation unit 120 instructs the voltage measurement unit 110 to measure the voltage of the battery unit 20 when the third time T3 has elapsed since the charging of the battery unit 20 was stopped. In response to this instruction, the voltage measurement unit 110 measures the voltage of the battery unit 20 (third voltage V3) (S118).

[0063] The battery performance estimation unit 120 calculates the difference between the fourth voltage V4 obtained as a result of the measurement process in S302 and the third voltage V3 obtained as a result of the measurement process in S118. Then, the battery performance estimation unit 120 determines whether or not the difference satisfies a predetermined criterion (S306). For example, the battery performance estimation unit 120 determines whether or not the absolute value of the difference between the fourth voltage V4 and the third voltage V3 is equal to or less than a predetermined reference value (threshold value). In this case, the battery performance estimation unit 120 determines that the criterion is satisfied when the absolute value of the difference between the fourth voltage V4 and the third voltage V3 is equal to or less than the predetermined reference value. Also, in this case, the battery performance estimation unit 120 determines that the criterion is not satisfied when the absolute value of the difference between the fourth voltage V4 and the third voltage V3 exceeds the predetermined reference value. That is, in the processing of S304, the battery performance estimation unit 120 determines whether or not the polarization generated in the battery unit 20 due to discharging has been eliminated based on the fluctuation value of the voltage of the battery unit 20 during a specified period after the charging operation in the second charging state.

[0064] If the difference between the fourth voltage V4 and the third voltage V3 satisfies the criterion (S306: YES), the battery performance estimation unit 120 estimates the performance of the battery unit 20 using the third voltage V3, as described with reference to Figures 5 and 6. In this case, the battery performance estimation unit 120 may estimate the performance of the battery unit 20 by using the fourth voltage V4 instead of or in addition to the fourth voltage V4. Specifically, the battery performance estimation unit 120 may estimate the SOC of the battery unit 20 by using the third voltage V3, the fourth voltage V4, or an average value of the third voltage V3 and the fourth voltage V4, or the like.

[0065] On the other hand, if the difference between the fourth voltage V4 and the third voltage V3 does not satisfy the criterion (S306: NO), the processes from S116 to S306 illustrated in Fig. 8 are repeated. That is, the battery performance estimation unit 120 repeats the above-mentioned processes until the newly measured fourth voltage V4 and the newly measured third voltage V3 satisfy the criterion. The newly measured third voltage V3 can also be called a fifth voltage to distinguish it from the third voltage V3 described above.

[0066] The feature of the control device 10 of this modification can also be expressed as follows. The control device 10 of the control device 10 measures the voltage of the battery unit 20 at each of two different time points (a first time point and a second time point). The battery performance estimation unit 120 of the control device 10 calculates the difference between a first voltage measured at the first time point and a second voltage measured at the second time point. Then, the battery performance estimation unit 120 of the control device 10 repeatedly performs a charging operation for the battery unit 20 for a predetermined time (a second time T2) and measures the voltage of the battery unit 20 until the difference becomes equal to or less than a predetermined reference value. Then, when the difference becomes equal to or less than a predetermined reference value, the battery performance estimation unit 120 measures the performance of the battery unit 20 using at least one of the first voltage measured at the first time point and the second voltage measured at the second time point.

[0067] According to this modification, the charging operation in the second state (e.g., charging operation at rated power) is repeated for the second time T2 until the polarization generated inside the battery module 20 during discharging is eliminated. As a result, it is expected that the estimation accuracy of the SOC of the battery module 20, and therefore the estimation accuracy of the SOH of the battery module 20, can be further improved.

[0068] From the viewpoint of the time efficiency of charging, it is not preferable to frequently stop charging. Therefore, a limit may be set on the number of repetitions of the charging operation in the second state (e.g., charging operation at rated power) over the second time T2. In this case, the battery performance estimation unit 120 is configured to temporarily store the number of repetitions in the memory 406 or the like. The battery performance estimation unit 120 is also programmed to exit the loop process when the number of repetitions temporarily stored in the memory 406 or the like reaches a specified number. By doing so, it is expected that the effect of suppressing the decrease in the time efficiency of charging can be suppressed.

[0069] Second embodiment The control device 10 according to this embodiment has the same configuration as the first embodiment or the modified example described above, except for the points described below. Fig. 9 is a diagram illustrating a functional configuration of the control device 10 according to the second embodiment. In this diagram, the battery performance estimation unit 120 further includes a condition determination unit 122 for determining a predetermined condition described later.

[0070] In this embodiment, when the usage environment of the battery module 20 satisfies a predetermined condition, the condition determination unit 122 does not execute the first estimation process and the second estimation process described in the above-mentioned first embodiment. In this case, the state of health (SOH) of the battery module 20 is estimated using an SOC estimated from a voltage at a stage when charging of the battery module 20 starts and an SOC estimated from a voltage at a stage when charging of the battery module 20 ends. Note that the "predetermined condition" in this embodiment includes various conditions related to polarization that may occur inside the battery module 20 due to discharge.

[0071] As an example, the predetermined condition includes a condition based on the temperature in the use environment of the battery unit 20. The temperature here may be the internal temperature of the battery or the atmospheric temperature of the battery unit 20. The predetermined condition (reference value of temperature) when the internal temperature of the battery is referred to is set higher than when the atmospheric temperature of the battery is referred to. This is because the internal temperature of the battery unit 20 is usually higher than the atmospheric temperature during use. Basically, the lower the temperature is, the more likely polarization is to occur inside the battery unit 20. Therefore, if the battery unit 20 is used in a state of a relatively high temperature, it can be said that the influence of the polarization caused by discharge on the accuracy of the performance estimation of the battery unit 20 is small. Therefore, the condition determination unit 122 temporarily stores the temperature during use of the battery unit 20 (for example, the average temperature during use) in the memory 406, etc., and does not execute the first estimation process and the second estimation process described in the first embodiment described above when the stored temperature during use exceeds the reference temperature. The reference temperature can be calculated based on experimental data or theoretical calculation. The calculated reference temperature is stored in a storage area accessible by the condition determining unit 122, such as the memory 406 or the storage device 408.

[0072] As another example, the predetermined condition includes a condition based on the time from when the use of the battery unit 20 is stopped to when the battery unit 20 is connected to the charger 22. The polarization caused in the battery unit 20 by discharging is gradually eliminated over time. Therefore, if a certain period of time has passed after the discharge of the battery unit 20 is completed, it can be said that it is not necessary to execute the characteristic process related to the control device 10 described above. In this case, the condition determination unit 122 counts the time from when the use of the battery unit 20 is stopped to when the charger 22 is connected. Alternatively, the condition determination unit 122 may obtain the time when the use of the battery unit 20 is stopped and the time when the charger 22 is connected, and calculate the elapsed time from the difference between these two points in time. If these elapsed times are equal to or longer than a reference time required for the polarization caused by discharging to be eliminated, the condition determination unit 122 does not execute the first estimation process and the second estimation process described in the first embodiment described above. Note that this reference time can be calculated based on experimental data or theoretical calculation. The calculated reference time is stored in a storage area accessible by the condition determination unit 122, such as the memory 406 or the storage device 408.

[0073] As yet another example, the predetermined condition includes a condition based on a load on the battery unit 20 during a predetermined period before the use of the battery unit 20 is stopped. The magnitude of polarization caused by discharge is proportional to the load on the battery unit 20 during use (for example, the magnitude of the current flowing through the battery unit 20). Therefore, the condition determination unit 122 can estimate the magnitude of polarization caused by discharge by referring to the load applied when the battery unit 20 is used. That is, the condition determination unit 122 can determine the necessity of the first estimation process and the second estimation process described in the above-mentioned first embodiment based on the load applied when the battery unit 20 is used. Here, if all information related to the load during use of the battery unit 20 is stored, there is a possibility that a large amount of storage area of ​​the control device 10 will be consumed. Therefore, the condition determination unit 122 preferably stores information related to the load applied to the battery unit 20 during a certain limited period, for example, the most recent 30 minutes, in the memory 406 or the like. Here, when the usage time of the battery unit 20 exceeds 30 minutes, the condition determination unit 122 overwrites the initially stored information with the latest information, thereby reducing the consumption of the storage area of ​​the control device 10. Thereafter, when the use of the battery unit 20 ends and the battery unit 20 is connected to the charging device 22, the condition determination unit 122 reads out information related to the load being used by the battery unit 20 stored in the memory 406 or the like. Then, the condition determination unit 122 compares, for example, the average value, maximum value, and intermediate value of the load with the reference value of the load. When the value obtained from the information stored in the memory 406 or the like is less than the reference value of the load, the condition determination unit 122 does not execute the first estimation process and the second estimation process described in the first embodiment. Note that this reference value of the load can be calculated based on experimental data or theoretical calculation. The calculated reference value of the load is stored in a storage area accessible by the condition determination unit 122, such as the memory 406 or the storage device 408.

[0074] The condition determination unit 122 may also determine the necessity of the first estimation process and the second estimation process described in the first embodiment by combining two or more of the above-mentioned various conditions. In this case, the condition determination unit 122 may perform different weighting for each condition.

[0075] The operation and effect of the control device 10 according to the second embodiment will be illustrated. In this embodiment, the first estimation process and the second estimation process described in the first embodiment are not executed when a predetermined condition is satisfied. The predetermined condition is set from various viewpoints as a condition under which it is determined that the degree of influence of polarization caused by discharge is small. Then, when the predetermined condition is satisfied, the state of health (SOH) of the battery unit 20 is estimated using the SOC estimated from the voltage at the stage when charging of the battery unit 20 is started and the SOC estimated from the voltage at the stage when charging of the battery unit 20 is completed. This is expected to have the effect of suppressing the decrease in the time efficiency of charging.

[0076] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0077] In addition, in the flowcharts used in the above description, multiple steps (processes) are described in order, but the order of execution of the steps performed in each embodiment is not limited to the order described. In each embodiment, the order of the steps shown in the figures can be changed to the extent that the content is not affected. In addition, the above-mentioned embodiments can be combined to the extent that the content is not contradictory. [Explanation of symbols]

[0078] 10 Control device 110 Voltage measurement section 120 Battery performance estimation section 122 Condition judgment section 20 Battery section 22 Charging equipment 24 Power system 30 Electric Drive Products 40 Integrated Circuits 402 Bus 404 Processor 404 Memory 406 Memory 408 Storage Devices 410 Input / Output Interface 412 Network Interface

Claims

1. A voltage measuring means for measuring the voltage of the battery; a battery performance estimation means for estimating the performance of the battery using the measured voltage of the battery; Equipped with The battery performance estimation means a first estimation process for estimating the performance of the battery using at least one of a first voltage and the second voltage when a difference between a first voltage measured before the start of charging and a second voltage measured after a first time has elapsed in a first charging state is equal to or smaller than a reference value; if the difference exceeds the reference value, a second estimation process is executed to estimate the performance of the battery using a third voltage measured after a charging operation in a second state, in which the charging power per unit time is higher than that in the first state, is performed for a second period of time. Control device.

2. The second state is a constant power charging state. The control device according to claim 1 .

3. The first state is a state in which charging is temporarily stopped. The control device according to claim 1 or 2.

4. The battery performance estimation means ceasing charging of the battery for a third period of time after the second period of time has elapsed; The voltage measuring means measuring the voltage of the battery after the third time has elapsed as the third voltage; The control device according to claim 1 or 2.

5. The voltage measuring means measuring a voltage of the battery at the time when the second time has elapsed as a fourth voltage; The battery performance estimation means if the difference between the third voltage and the fourth voltage exceeds the reference value, a third estimation process is performed to estimate the performance of the battery using a fifth voltage measured after performing the charging operation in the second state again. The control device according to claim 4.

6. The second time period is 10 minutes or more and 20 minutes or less. The control device according to claim 1 or 2.

7. the first time period is less than the second time period; The control device according to claim 1 or 2.

8. The battery performance estimation means estimates at least one of a State of Charge and a State of Health of the battery as the performance of the battery. The control device according to claim 1 or 2.

9. The battery performance estimation means When a usage environment of the battery satisfies a predetermined condition, the first estimation process and the second estimation process are not executed. The control device according to claim 1 or 2.

10. the predetermined condition is based on at least one of a temperature in an environment in which the battery is used, a time from when the use of the battery is stopped to when the battery is connected to a charger, and a load on the battery during a predetermined period before the use of the battery is stopped; The control device according to claim 9.

11. a voltage measuring means for measuring a voltage of the battery at a first point in time and at a second point in time that is later than the first point in time; a battery performance estimation means for repeatedly performing a charging operation for the battery for a predetermined time and measuring the voltage of the battery until a difference between a first voltage at the first time point and a second voltage at the second time point becomes equal to or less than a reference value, and estimating performance of the battery using at least one of the first voltage and the second voltage when the difference becomes equal to or less than the reference value; A control device comprising:

12. At least one computer a voltage measurement process for measuring a battery voltage; a battery performance estimation process for estimating the performance of the battery using the measured voltage of the battery; Run, In the battery performance estimation process, the at least one computer a first estimation process for estimating performance of the battery using at least one of a first voltage and the second voltage when a difference between a first voltage measured before the start of charging and a second voltage measured after a first time has elapsed in a first charging state is equal to or smaller than a reference value; if the difference exceeds the reference value, a second estimation process is executed to estimate the performance of the battery using a third voltage measured after a charging operation in a second state, in which the charging power per unit time is greater than that in the first state, is performed for a second period of time. A battery performance estimation method comprising:

13. At least one computer measuring a voltage of the battery at a first time point and at a second time point that is later than the first time point; repeating a charging operation for a predetermined time on the battery and measuring the voltage of the battery until a difference between a first voltage at the first time point and a second voltage at the second time point becomes equal to or less than a reference value; estimating the performance of the battery using at least one of the first voltage and the second voltage when the difference becomes equal to or less than the reference value; A battery performance estimation method comprising:

14. At least one computer, a voltage measuring means for measuring the voltage of the battery; and a battery performance estimation means for estimating the performance of the battery using the measured voltage of the battery; Function as a The battery performance estimation means a first estimation process for estimating the performance of the battery using at least one of a first voltage and the second voltage when a difference between a first voltage measured before the start of charging and a second voltage measured after a first time has elapsed in a first charging state is equal to or smaller than a reference value; if the difference exceeds the reference value, a second estimation process is executed to estimate the performance of the battery using a third voltage measured after a charging operation in a second state, in which the charging power per unit time is higher than that in the first state, is performed for a second period of time. A program that includes:

15. At least one computer, a voltage measuring means for measuring a voltage of the battery at a first point in time and at a second point in time that is later than the first point in time; and a battery performance estimation means for repeatedly executing a charging operation for the battery for a predetermined time and measuring the voltage of the battery until a difference between a first voltage at the first time point and a second voltage at the second time point becomes equal to or less than a reference value, and estimating the performance of the battery using at least one of the first voltage and the second voltage when the difference becomes equal to or less than the reference value; A program to function as a

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