JP7380068B2 - Power supply device, estimation method and computer program - Google Patents

Description

The present invention relates to a power supply device, an estimation method, and a computer program.

Lead-acid batteries are used in various moving bodies such as vehicles, and supply power to various loads. Typically, a lead-acid battery supplies power to a starter when starting an internal combustion engine (hereinafter simply referred to as the "engine"). Lead-acid batteries may become over-discharged due to various causes, causing sulfation and decreasing capacity, making it impossible to start the engine.
Lead-acid batteries may suddenly become unusable without any symptoms indicating that they are at the end of their lifespan. It is difficult to properly determine when to replace lead-acid batteries.

To easily and appropriately estimate the battery's SOH (State of Health: capacity maintenance rate, capacity decline rate, resistance value, etc.) in deciding whether to use lead-acid batteries, how to use them, when to replace them, etc. is important.

In the state determination device of Patent Document 1, a sub-battery such as a lead-acid battery and a main battery are connected via a main relay and a bidirectional converter. When the vehicle is stopped, that is, when the main relay is off, power is supplied from the sub-battery to the smoothing capacitor via the bidirectional converter, and the internal resistance of the sub-battery is estimated from the current and voltage at that time, and deterioration is estimated. .

Japanese Patent Application Publication No. 2014-230343

In the state determination device of Patent Document 1, power is supplied from the sub-battery to the smoothing capacitor and the deterioration of the sub-battery is estimated by detecting the current and voltage, so the circuit configuration is complex and the estimation process is complicated. It is. It is desired to easily and appropriately estimate the deterioration of a power storage element such as a lead-acid battery with a simple configuration.

An object of the present invention is to provide a power supply device, an estimation method, and a computer program that can easily and appropriately estimate the deterioration of a power storage element with a simple configuration.

The power supply device according to one aspect of the present invention includes a first power storage element, a second power storage element which is different in type from the first power storage element, and which is capable of supplying power to the first power storage element, and a second power storage element, which is different in type from the first power storage element. and an estimation unit that estimates deterioration of the first power storage element based on the number of times the first power storage element is charged.

The estimation method according to one aspect of the present invention charges the first power storage element with power supplied from a second power storage element different in type from the first power storage element, and charges the first power storage element from the second power storage element to the first power storage element. Deterioration of the first power storage element is estimated based on the number of times of charging.

A computer program according to one aspect of the present invention includes a process of estimating deterioration of the first power storage element based on the number of times the first power storage element is charged from a second power storage element different in type from the first power storage element. have the computer execute it.

With the above configuration, deterioration of the power storage element can be easily and appropriately estimated with a simple configuration.

FIG. 1 is a block diagram showing the configuration of a vehicle including a power supply system according to an embodiment. It is a graph showing the first relationship between the number of times n of charging within one week and the capacity reduction rate. It is a flowchart which shows the procedure of the estimation process of the deterioration of the 1st battery by a control part. FIG. 3 is a block diagram showing a state in which the switch is turned on and the first battery is charged from the second battery.

(Summary of embodiment)
The power supply device includes a first power storage element, a second power storage element that is different in type from the first power storage element and is capable of supplying power to the first power storage element, and a second power storage element that supplies power from the second power storage element to the first power storage element. and an estimation unit that estimates deterioration of the first power storage element based on the number of times of charging.

The present inventors have proposed that in a power supply device including a first power storage element and a second power storage element capable of supplying power to the first power storage element, the SOC (State Of Charge) of the first power storage element becomes low. It has been found that when the number of times the second power storage element is charged increases, it can be determined that the first power storage element has deteriorated.
According to the above configuration, it is possible to easily and appropriately estimate the deterioration of the first power storage element with a simple configuration based on the number of times of charging.

In the power supply device described above, the estimation unit may estimate deterioration of the first power storage element based on the number of times of charging within a predetermined period.

If the number of times of charging within a predetermined period is large, that is, the frequency of charging is high, it is considered that the first power storage element is deteriorating. According to the above configuration, it is possible to more appropriately estimate the deterioration of the first power storage element based on the frequency of the number of times of charging.

The above-described power supply device may include a notification unit that notifies deterioration of the first power storage element based on the number of times the first power storage element is charged from the second power storage element.

According to the above configuration, the user can determine whether or not the first power storage element can be used, how to use it in the future, the timing of replacement, etc. by reporting the deterioration of the first power storage element.
Conventionally, users of lead-acid batteries have not been able to obtain objective information for making decisions such as replacement timing. With the above configuration, the user can know objective information such as the number of times the first power storage element is charged from the second power storage element, and can use it for decision making.

The estimation method is based on charging the first power storage element with electric power supplied from a second power storage element different in type from the first power storage element, and the number of times the second power storage element charges the first power storage element. Then, deterioration of the first power storage element is estimated.

The computer program causes the computer to execute a process of estimating deterioration of the first power storage element based on the number of times the first power storage element is charged from a second power storage element different in type from the first power storage element.

(Details of embodiment)
FIG. 1 is a block diagram showing the configuration of a vehicle including a power supply system 1 according to an embodiment.
The vehicle includes a power supply system 1, an ignition switch (hereinafter referred to as IGN) 11, a control device 12, an alternator 13, a starter 14, and an auxiliary machine 15.
The power supply system 1 includes a first battery 2, CMUs (Cell Monitoring Units) 3 and 5, a second battery 4, current sensors 6 and 7, a switch section 8, and a control device 9. When the first battery 2 is a lead-acid battery, the control device 12 may also serve as the CMU 3. Alternatively, if the control device 9 also serves as the functions of the CMUs 3 and 5, the CMUs 3 and 5 may not be provided in the individual batteries 2 and 4. If the circuit board mounted on the second battery 4 also serves as the function of the control device 9, the control device 9 may not be provided.
In this embodiment, the control device 9 functions as an estimator. Alternatively, the control device 12 located outside the power supply system 1 may perform the deterioration estimation based on the information output by the control device 9. Further, a computer or a server connected by wire or wirelessly to the control device 9 or the control device 12 may perform the deterioration estimation based on the information output by the control device 9.

The IGN 11 switches the vehicle to an OFF state when the vehicle is stopped, an ON state before and when the vehicle is running, and a start state when the engine is started. The alternator 13 converts the rotational force of the engine into regenerative power during braking and when the accelerator is off. Starter 14 starts the engine. The starter 14 is switched to the start state by the IGN 11, and power is supplied from the first battery 2 to the starter 14, which rotates the starter 14. The rotational force of the starter 14 is transmitted to the engine via the crankshaft, and the engine starts. . Examples of the auxiliary equipment 15 include a room lamp, various lights, an air conditioner, a fan, a radio, a television, a CD player, a car navigation system, and the like.

The control device 12 includes a control section 12a, a display section 12b, and a communication section 12c. In FIG. 1, a storage section, a timekeeping section, an input section, etc. are omitted.
The control unit 12a includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls the operation of the vehicle.
The display section 12b can be configured with a liquid crystal panel, an organic EL (Electro Luminescence) display panel, or the like. The control unit 12a performs control to display required information on the display unit 12b.
The communication unit 12c has a function of communicating with other devices such as the control device 9 via a network, and can send and receive required information.

In this embodiment, the first battery 2 is a lead acid battery. The first battery 2 includes a case, a positive terminal, a negative terminal, and a group of electrode plates each housed in a plurality of cell chambers within the case. The cell chamber contains an electrolytic solution containing dilute sulfuric acid, and the entire electrode plate group is immersed in the electrolytic solution. The electrode plate group includes a plurality of positive electrode plates, a plurality of negative electrode plates, and a separator. The plurality of positive electrode plates and the plurality of negative electrode plates are arranged alternately.

The second battery 4 is a lithium ion secondary battery. The second battery 4 may be an assembled battery formed by connecting a plurality of cells in series. The cell includes a case, a lid plate, a positive electrode terminal and a negative electrode terminal provided on the lid plate, and an electrode body. The cell is not limited to a prismatic cell, but may be a pouch cell or a cylindrical cell. The electrode body is formed by laminating a positive electrode plate, a separator, and a negative electrode plate, and is housed in a case. The electrode body may be obtained by winding a positive electrode plate and a negative electrode plate into a flat shape with a separator in between. The electrode body is not limited to a wound type, but may be a laminated type in which a rectangular positive electrode plate, a separator, and a negative electrode plate are laminated.

The switch unit 8 may include two switches 81 and 82 connected in series. In FIG. 1, the charging control circuit is omitted. The switch 81 and the switch 82 are made of switching elements such as relays and power MOSFETs that can flow large currents. A connection point between switch 81 and switch 82 is connected to starter 14 , auxiliary machine 15 , and alternator 13 . The other end of the switch 81 and the other end of the switch 82 are connected to the positive terminal of the first battery 2 and the positive terminal of the second battery 4, respectively.

When the power supply system 1 receives regenerated power supplied from the alternator 13 , one of the first battery 2 and the second battery 4 is connected to the alternator 13 by turning on one of the switch 81 and the switch 82 .
When discharging from the power supply system 1 to the starter 14 or the auxiliary device 15, by turning on one of the switches 81 and 82, one of the first battery 2 and the second battery 4 is supplied to the starter 14 or the auxiliary device 15. Connecting.
FIG. 1 shows a state in which the switch 81 is on and power is being supplied from the first battery 2 to the starter 14.

The CMUs 3 and 5 are electronic control units (monitoring boards) that monitor the voltage, current, and other states of the first battery 2 and the second battery 4. The CMUs 3 and 5 each include a voltage sensor and detect the voltages of the first battery 2 and the second battery 4. The current sensor 6 is connected to the CMU 3, and the CMU 3 detects the current flowing through the first battery 2. The current sensor 7 is connected to the CMU 5, and the CMU 5 detects the current flowing through the second battery 4.

The control unit 91 may have the same configuration as the control unit 12a, and controls the operation of the power supply system 1.
The control unit 91 executes deterioration estimation processing by reading and executing a deterioration estimation program 97, which will be described later.

The clock section 93 counts the elapsed time.
The input unit 94 receives input of the detection results of the current and voltage of the first battery 2 and the second battery 4 from the CMU 3 and the CMU 5 .
The communication unit 95 has a function of communicating with other devices such as the control device 12 via the network 10, and can send and receive required information.

The storage unit 92 stores various programs and data. A deterioration estimation program 97 is stored in the storage unit 92 . The deterioration estimation program 97 is provided in a state stored in a computer-readable recording medium 96 such as a CD-ROM, DVD-ROM, or USB memory, and is stored in the storage unit 92 by installing it in the control device 9. . Alternatively, the deterioration estimation program 97 may be acquired from an external computer (not shown) connected to a communication network and stored in the storage unit 92.

The storage unit 92 also stores charging/discharging history data 98 . The charging/discharging history is the operation history of the first battery 2 and the second battery 4, and includes information indicating the period (usage period) during which the first battery 2 and the second battery 4 were charged or discharged, and information indicating the period of use during the usage period. It includes information regarding charging or discharging performed by the first battery 2 and the second battery 4, information regarding charging from the second battery 4 to the first battery 2, and the like. The information indicating the period of use of the first battery 2 and the second battery 4 includes information indicating the start and end points of charging or discharging, the cumulative period of use during which the first battery 2 and the second battery 4 were used, etc. It is information. The information regarding the charging or discharging performed by the first battery 2 and the second battery 4 is information indicating the voltage, rate, etc. during charging or discharging performed by the first battery 2 and the second battery 4. The information regarding charging from the second battery 4 to the first battery 2 is information including the voltage of the first battery 2 before charging, the SOC, the number of times n of charging within one week, etc.

A threshold table 99 is also stored in the storage unit 92 .
A first relationship between the number of times the second battery 4 is charged to the first battery 2 within a predetermined period of time, such as one week, and the capacity reduction rate is determined in advance through experiments.
FIG. 2 is a graph showing the first relationship between the number of times n of charging within one week and the capacity reduction rate. The horizontal axis is the number of times n of charging, and the vertical axis is the capacity reduction rate (%). The control unit 91 determines n as a threshold b when the capacity reduction rate exceeds the allowable amount, and stores it in the threshold table 99. The first relationship may be determined for each usage condition such as the average temperature and rate of the first battery 2, and a plurality of threshold values b may be stored in the threshold value table 99. As the first relationship, the relationship between the number of times of charging and the capacity retention rate or resistance value may be determined.

FIG. 3 is a flowchart showing a procedure for estimating deterioration of the first battery 2 by the control unit 91. The control unit 91 repeats the following process at every predetermined sampling time.
The control unit 91 determines whether it is reset time (S1). For example, the control unit 91 counts the number of times n of charging from the second battery 4 to the first battery 2 every week, and determines deterioration. The control unit 91 determines whether it is the reset time by determining whether one week has passed since the previous reset.

If the control unit 91 determines that it is not the reset time (S1: NO), it advances the process to S3.
When the control unit 91 determines that it is the reset time (S1: YES), it resets the number of times n of charging to "0" (S2).
The control unit 91 determines whether the engine has stopped (S3). If the control unit 91 determines that the engine is not stopped (S3: NO), it ends the process.

When the control unit 91 determines that the engine has stopped (S3: YES), the control unit 91 acquires the voltage of the first battery 2 using the CMU 3 (S4).
The control unit 91 obtains the SOC of the first battery 2 from the SOC-OCV (open circuit voltage) curve or the like. The control unit 91 determines whether the acquired SOC is less than or equal to a threshold value a (S5). The threshold value a is the SOC at which charging of the first battery 2 from the second battery 4 is required. When the control unit 91 determines that the SOC is not equal to or less than the threshold value a (S5: NO), the process ends.
If the control unit 91 determines that the SOC is less than or equal to the threshold value a (S5: YES), it turns on both the switches 81 and 82, and charges the first battery 2 from the second battery 4 (S6).
FIG. 4 is a block diagram showing a state in which the switches 81 and 82 are turned on to charge the first battery 2 from the second battery 4.

The control unit 91 increments the number of times n of charging by "1" (S7).
The control unit 91 reads the threshold value table 99, obtains the threshold value b, and determines whether n is greater than or equal to b (S8). When the threshold value table 99 is determined for each usage condition such as the average temperature of the first battery 2 and the charging rate of the starter 14, the control unit 91 acquires the threshold value b according to the condition.

When the control unit 91 determines that n is greater than or equal to b (S8: YES), the control unit 91 notifies the control unit 12a of the control device 12 that the first battery 2 has deteriorated (S9), and the process proceeds to S10. Proceed. The control unit 12a displays on the display unit 12b that the first battery 2 has deteriorated. The means for notifying the user may include audible notification, displaying a message on the display of the car navigation system, etc. Note that the notification may be performed while the engine is operating. When the control device 9 includes a display section or an audio output section, the display section or the audio output section may be used to perform the notification.

The control unit 91 determines whether or not to end charging (S10). The control unit 91 determines whether to terminate charging by determining whether the charging time has exceeded a predetermined time, or determining whether the remaining capacity of the second battery 4 has become below a threshold value. judge. When the control unit 91 determines that charging is not to be terminated (S10: NO), this determination process is repeated.
When the control unit 91 determines to end charging (S10: YES), it ends the process.

According to this embodiment, the deterioration of the first battery 2 can be easily and appropriately estimated with a simple configuration based on the number of times n of charging within one week.
By reporting the deterioration, the user can decide whether to use the first battery 2, how to use it in the future, whether to replace it, etc. As described above, it is difficult to know when to replace a lead-acid battery, but the user can know when to replace it by reporting deterioration.

The embodiments described above are not limiting. The scope of the present invention is intended to include all changes within the meaning and scope equivalent to the claims.
The present invention is not limited to estimating deterioration based on the number of times n of charging within one week. Deterioration can be estimated based on the number of times of charging within a predetermined period. Deterioration may be estimated based on the number of times of charging after a predetermined period of time has elapsed. Alternatively, the deterioration may be estimated by counting the total number of times of charging from the first time without dividing the period, and determining whether the counted number of times exceeds a threshold value determined in advance by experiment.

The estimation method according to the present invention is applicable to vehicles other than engine vehicles (hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs)), mobile objects other than vehicles, power generation facilities, power demand facilities, and regenerative power storage devices for railways. It can also be applied to power supply devices such as
The first battery 2 is not limited to a lead acid battery, and the second battery 4 is not limited to a lithium ion secondary battery. The first battery 2 and the second battery 4 may be other secondary batteries, primary batteries, or electrochemical cells such as capacitors.

1 Power system (power supply device)
2 First battery (power storage element)
3,5 CMU
4 Second battery (storage element)
6, 7 Current sensor 8 Switch section 81, 82 Switch 9, 12 Control device 91, 12a Control section 92 Storage section 93 Time measurement section 94 Input section 95, 12c Communication section 96 Recording medium 97 Deterioration estimation program 98 History data 99 Threshold table 12b Display section

Claims (4)

a first energy storage element;
a second power storage element that is different in type from the first power storage element and capable of supplying power to the first power storage element;
an estimation unit that estimates deterioration of the first power storage element based on the number of times the first power storage element is charged from the second power storage element ;
The estimation unit calculates the average temperature of the first power storage element within a predetermined period or the charging rate,
reading different threshold values according to the calculated average temperature or the rate of charging;
Determining whether the number of times of charging is equal to or greater than the read threshold;
If it is determined that the number of times of charging is equal to or greater than a read threshold value, the power supply device is estimated to have deteriorated . 2. The threshold value is stored as the number of times the capacity decrease rate exceeds an allowable capacity decrease rate based on the relationship between the capacity decrease rate and the number of times of charging within the predetermined period, which differs depending on the average temperature and/or charging rate. The power supply described in . charging the first power storage element with power supplied from a second power storage element different in type from the first power storage element;
Calculating the average temperature of the first power storage element within a predetermined period or the rate of charging,
reading different threshold values according to the calculated average temperature or the rate of charging;
determining whether the number of times the second power storage element charges the first power storage element is equal to or greater than a read threshold;
An estimation method that estimates that the first power storage element has deteriorated when it is determined that the number of times of charging is equal to or greater than a read threshold value. A computer that controls charging of the first power storage element from a second power storage element different in type from the first power storage element,
Calculating the average temperature of the first power storage element within a predetermined period or the rate of charging,
reading different threshold values according to the calculated average temperature or the rate of charging;
determining whether the number of times the second power storage element charges the first power storage element is equal to or greater than a read threshold;
If it is determined that the number of times of charging is equal to or greater than the read threshold, it is estimated that the first storage element has deteriorated.
A computer program that causes a computer to perform a process.

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