Battery monitoring device

Abstract

To provide a monitoring device capable of monitoring whether a storage battery is being used properly. [Solution] The monitoring device 10 for a storage battery 1 according to the present invention comprises a measurement unit 11 that measures the voltage and current values ​​between a pair of external terminals 1a, 1b of the storage battery 1, a judgment unit 12 that judges the improper use state of the storage battery 1 based on the voltage and current values ​​of the storage battery 1 measured by the measurement unit 11, and a recording unit 13 that records the start date and time and end date and time of the improper use state as a data log.

Description

[Technical Field]

[0001] The present invention relates to a monitoring device for a storage battery, and more particularly to a monitoring device for monitoring the operation of a storage battery that leads to a reduction in its lifespan. [Background technology]

[0002] Storage batteries such as lead-acid batteries and lithium-ion batteries are widely used. Storage batteries are a type of secondary battery that can be recharged and reused, allowing for long-term use. However, proper use is required, as overcharging, over-discharging, and other practices that can damage the battery can shorten its lifespan. Normally, when charging a storage battery, a charging device monitors and controls the voltage and current during charging to prevent overcharging.

[0003] Regarding storage batteries, for example, Patent Document 1 describes a charging system that includes a charging device, a charging cable interposed between the battery and the charging device, and a monitoring device that is provided separately from the charging device and acquires battery current information and transmits individual information related to the charging and discharging of the battery to the charging device via wireless communication. The monitoring device calculates the amount of discharge based on the current and time discharged from the battery to a group of loads and transmits this amount of discharge as individual information to the charging device. The charging device performs charging control to charge the battery based on the amount of discharge received from the monitoring device. This allows the charging device to perform charging control to charge the battery based on the accurate amount of discharge received from the monitoring device, allowing the battery to be appropriately charged regardless of the remaining charge.

[0004] Patent Document 2 also describes a method for providing battery status that allows a user to easily recognize the status of a storage battery. This method installs storage battery status providing software in a user terminal device that includes a receiving unit and an output unit, sets the receiving unit to be able to receive storage battery information from a storage battery mounted on a vehicle via communication, receives storage battery information recorded when the storage battery is in a predetermined condition via communication, and outputs the status of the storage battery based on the storage battery information received by the receiving unit to the output unit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2024-033742 [Patent Document 2] Patent Publication No. 2021-083252 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional battery systems, the charging device is equipped with a function to prevent overcharging. However, if this function does not function properly, the battery may deteriorate, necessitating the replacement of the battery. Furthermore, if the battery is left unused for a long period of time, the battery may deteriorate and its performance may drop significantly. Although these problems are actually problems with the battery's usage, they are often misdiagnosed as problems with the battery itself. This makes it difficult to identify the root cause of battery deterioration.

[0007] Therefore, an object of the present invention is to provide a monitoring device that can correctly evaluate whether a storage battery is being used properly. [Means for solving the problem]

[0008] In order to solve the above problems, the storage battery monitoring device of the present invention is characterized by comprising a measurement unit that measures the voltage and current of the storage battery, a judgment unit that judges an inappropriate use state of the storage battery based on the voltage value and the current value of the storage battery measured by the measurement unit, and a recording unit that records the start date and time and the end date and time of the inappropriate use state as a data log.

[0009] According to the present invention, it is possible to evaluate whether the charging and discharging operation of a storage battery is being performed properly or whether the storage battery has not been used for a long time, and to determine whether the deterioration of the storage battery is due to the storage battery itself or to an external factor such as an abnormal operation of the charging device, thereby making it possible to determine the cause of the deterioration of the storage battery.

[0010] In the present invention, it is preferable that the inappropriate use state includes an overcharged state of the storage battery, and the determination unit determines the overcharged state when the voltage value reaches a first threshold voltage higher than the rated voltage of the storage battery and the current value is equal to or greater than the first threshold current for a duration equal to or greater than a first threshold period. This makes it possible to determine that deterioration of the storage battery is due to overcharging.

[0011] In the present invention, the inappropriate use state preferably includes an over-discharge state of the storage battery, and the determination unit preferably determines the over-discharge state when the voltage value becomes equal to or lower than a second threshold voltage that is lower than a rated voltage of the storage battery and the current value becomes equal to or higher than the second threshold current for a duration equal to or longer than a second threshold period. This makes it possible to determine that the deterioration of the storage battery is due to over-discharge.

[0012] In the present invention, the inappropriate use state preferably includes an over-discharge state of the storage battery. The determination unit determines the over-discharge state when the voltage value becomes equal to or less than a second threshold voltage lower than the rated voltage of the storage battery and the current value becomes equal to or greater than a second threshold current. When the determination unit determines that the storage battery is in the over-discharge state, it records the start date and time of the over-discharge state and the voltage and current values ​​at that time as the data log, and then stops measuring the voltage and current values ​​of the storage battery by the measurement unit. When the over-discharge state of the storage battery ends, it resumes measuring the voltage and current values ​​of the storage battery by the measurement unit and records the start date and time of the over-discharge state and the voltage and current values ​​at that time as the data log. This makes it possible to determine that deterioration of the storage battery is due to over-discharge. Furthermore, deterioration of the storage battery due to the monitoring device continuing to consume power from the over-discharged storage battery can be prevented.

[0013] In the present invention, the inappropriate use state preferably includes a state in which the storage battery has not been used for a long time, and the determination unit preferably determines that the storage battery has been in the long-term unused state when the state in which the current value is equal to or less than a third threshold current continues for a third threshold period or longer, thereby making it possible to determine that deterioration of the storage battery is caused by the long-term unused state.

[0014] The monitoring device according to the present invention may further include a temperature sensor for measuring the temperature of the storage battery, and the determination unit may determine that the storage battery is in an inappropriate use state when the temperature measured by the temperature sensor is equal to or greater than a first temperature threshold that is higher than the usable temperature or equal to or less than a second temperature threshold that is lower than the room temperature. This improves the accuracy of detecting an overcharge state.

[0015] The monitoring device according to the present invention preferably further includes a communication unit for communicating data with an external device, and the communication unit preferably transmits the data log to the external device in response to a request from the external device, thereby enabling the results of monitoring the storage battery by the monitoring device to be confirmed.

[0016] The monitoring device according to the present invention may be integrated into the main body of the storage battery, or may be configured to be detachable from the storage battery. In the former case, the reliability of the monitoring device can be improved. In the latter case, it can be retrofitted to a storage battery that does not have a monitoring device, thereby expanding the scope of monitoring.

[0017] In the present invention, the storage battery may also be measured in a storage battery group consisting of a plurality of storage battery units connected in series, in parallel, or a combination thereof, and the measurement unit may be connected to a pair of external terminals of the storage battery group. In this way, the monitoring device of the present invention can monitor a plurality of storage battery units collectively. [Effects of the Invention]

[0018] As described above, the present invention can provide a monitoring device that can correctly evaluate whether a storage battery is being used appropriately. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a storage battery monitoring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating the operation of the monitoring device during charging of the storage battery. [Figure 3] FIG. 3 is a diagram illustrating the operation of the monitoring device during the discharging operation of the storage battery. [Figure 4] FIG. 4 is a flowchart showing a method for monitoring a storage battery using the monitoring device according to this embodiment. [Figure 5] FIG. 5 is a flowchart illustrating an example of a method for determining whether a storage battery is in an overcharged state. [Figure 6] FIG. 6 is a flowchart illustrating an example of a method for determining whether a storage battery is in an over-discharged state. [Figure 7] FIG. 7 is a flowchart illustrating another example of a method for determining whether a storage battery is in an over-discharged state. [Figure 8]FIG. 8 is a flowchart illustrating an example of a method for determining whether a storage battery has been unused for a long period of time. [Figure 9] FIG. 9 is a block diagram that schematically shows the configuration of a storage battery system to which the storage battery monitoring device according to this embodiment is applied. [Figure 10] FIG. 10 is a block diagram that schematically shows another configuration of a storage battery system to which the storage battery monitoring device according to this embodiment is applied. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] FIG. 1 is a block diagram showing a schematic configuration of a storage battery monitoring device according to an embodiment of the present invention.

[0022] As shown in Figure 1, this monitoring device 10 includes a measurement unit 11 that measures the voltage and current of the storage battery 1, a judgment unit 12 that judges whether the storage battery 1 is in an inappropriate state of use, such as an overcharged state, based on the voltage and current values ​​of the storage battery 1 measured by the measurement unit 11, a recording unit 13 that records the start date and time and the end date and time of the inappropriate state of use as a data log, a display unit 14 that visually indicates the usage state of the storage battery 1, a communication unit 15 that communicates data with an external device 5 such as a smartphone, and a power supply unit 16 that converts the power supplied from the storage battery 1 into a voltage and supplies it to each unit.

[0023] The type of storage battery 1 is not particularly limited, and a lead-acid battery, a lithium-ion battery, a nickel-metal hydride battery, or the like can be used. The nominal voltage (rated voltage) of the storage battery 1 varies depending on the type of storage battery and the number of cells, and is determined appropriately depending on the use and purpose of the storage battery system. For example, in the case of a lead-acid battery, the nominal voltage per cell is approximately 2.0 V, and a 12 V automotive battery has an internal structure in which six cells are connected in series. In the case of a lithium-ion battery, one or more battery cells are connected to a BMS (Battery Management System), and the nominal voltage is determined according to the number of battery cells. Generally, the nominal voltage (cell voltage) of a single lithium-ion battery is approximately 3.7 V, and the single cell voltage ranges from 2.7 to 4.2 V.

[0024] The monitoring device 10 is attached to the storage battery 1, and a pair of input terminals 11a, 11b of the monitoring device 10 is connected to a pair of external terminals 1a, 1b (positive and negative poles) of the storage battery 1. The power required for the operation of the monitoring device 10 is supplied from the storage battery 1, but a dedicated auxiliary battery may be provided in case the storage battery 1 runs out of charge.

[0025] The monitoring device 10 may be retrofitted to the storage battery 1, or may be built into the main body (housing) of the storage battery 1 from the beginning and integrated therewith. Typically, the monitoring device 10 retrofitted to the storage battery 1 is not removed and is used continuously until the storage battery 1 is disposed of. In other words, the retrofit type monitoring device 10 is detachable from the storage battery 1, but is not frequently attached to or detached from the storage battery 1.

[0026] The measurement unit 11 continuously measures the voltage and current values ​​of the storage battery 1 at a fixed sampling period (e.g., every 1 second). The measurement values ​​are temporarily stored as digital values ​​in the recording unit 13, and later, only necessary measurement values ​​are retained and unnecessary measurement values ​​are deleted. The determination unit 12 includes an overcharge state determination unit 12a that determines an overcharge state when the voltage value of the storage battery 1 during charging exceeds a predetermined threshold voltage (first threshold voltage), an overdischarge state determination unit 12b that determines an overdischarge state when the voltage value of the storage battery 1 falls below a predetermined threshold voltage (second threshold voltage), and a long-term unused state determination unit 12c that determines whether the storage battery 1 is in a long-term unused state. The determination unit 12 also includes a time counter that measures time. The determination unit 12 is preferably composed of a semiconductor IC such as an ASIC. The recording unit 13 is a semiconductor memory such as RAM, and records various data including the details of the improper use state, the start date and time, and the end date and time.

[0027] The display unit 14 is, for example, an LED lamp, and is configured to light up or flash while an improper use state of the storage battery 1 is detected. The display unit 14 may be a liquid crystal display. When a liquid crystal display is used, the display unit 14 can display setting information (threshold voltage, threshold current, etc.) within the monitoring device 10.

[0028] The communication unit 15 is for performing data communication with the external device 5. The data communication method is not particularly limited, and may be short-range wireless communication such as Bluetooth or NFC, or wired communication such as USB. The monitoring device 10 transmits a data log to the external device 5 in response to a request from the external device 5.

[0029] The external device 5 is capable of data communication with the monitoring device 10 and can read out the data log recorded in the recording unit 13 of the monitoring device 10. The external device 5 can graphically display the details of the inappropriate use state, as well as the start date and time and the end date and time.

[0030] The power supply unit 16 is connected to a pair of input terminals 11a, 11b of the monitoring device 10 together with the measurement unit 11. The power supplied from the storage battery 1 is converted to a predetermined voltage by the power supply unit 16 and then supplied to each unit constituting the monitoring device 10 (the measurement unit 11, the determination unit 12, the recording unit 13, the display unit 14, and the communication unit 15). The power supply unit 16 may have a function to automatically stop the power supply to each unit when the output voltage of the storage battery 1 drops, and a restart function to resume the power supply to each unit when the output voltage of the storage battery 1 returns to a voltage equal to or higher than the cut-off voltage. This makes it possible to avoid a situation in which the over-discharge state of the storage battery 1 worsens due to the monitoring device 10 continuing to operate despite a drop in the state of charge of the storage battery 1.

[0031] FIG. 2 is a diagram illustrating the operation of the monitoring device 10 during the charging operation of the storage battery 1. In FIG.

[0032] As shown in Figure 2, when charging the storage battery 1, a charging device 2 is connected to a pair of external terminals 1a, 1b, and power is supplied from the charging device 2, thereby charging the storage battery 1. Normally, the charging device 2 has an overcharge prevention function 2a. The overcharge prevention function 2a monitors the charging state of the storage battery 1 and stops the charging operation when overcharge is detected.

[0033] The monitoring device 10 according to this embodiment provides an overcharge monitoring function that is installed on the storage battery 1 side, separate from the overcharge prevention function 2a of the charging device 2. However, the monitoring device 10 only detects and records an overcharge state, and does not have the function of preventing overcharge. The monitoring device 10 according to this embodiment simply monitors from the outside whether the overcharge prevention function 2a of the charging device 2 is working properly.

[0034] The overcharge state of the storage battery 1 is detected primarily by monitoring changes in the output voltage and output current of the storage battery 1. In an overcharge state, the voltage of the storage battery 1 continues to rise, and the charging current tends to become abnormally high. For example, a lead-acid battery with a nominal voltage of 12 V is generally charged to approximately 14.4 V, but in an overcharge state, the voltage may significantly exceed 14.4 V. The measurement unit 11 and overcharge state determination unit 12a of the monitoring device 10 detect such voltage changes and determine that the storage battery 1 is in an overcharge state if the voltage value exceeds a predetermined threshold voltage (first threshold voltage) that is higher than the rated voltage of the storage battery 1. This threshold voltage can be, for example, 15 V, and can be set and changed as desired.

[0035] When detecting an overcharged state, the current value of the storage battery 1 may also be measured, and if the voltage value exceeds a predetermined threshold voltage (first threshold voltage) and the current value exceeds a predetermined threshold current (first threshold current), the storage battery 1 may be determined to be in an overcharged state. The threshold current in this case may be, for example, 0.1 A, and may be set or changed as desired. By using not only the voltage value but also the current value to determine whether or not the storage battery 1 is in an overcharged state, the accuracy of determining whether or not the storage battery 1 is in an overcharged state can be improved.

[0036] An overcharged state causes the temperature of the storage battery 1 to rise. If the overcharged state continues, there is a risk that the electrolyte will boil or gas will be generated. Therefore, the monitoring device 10 may monitor the temperature of the storage battery 1 using the temperature sensor 11c, and may determine that the storage battery 1 is in an overcharged state when the temperature measurement value of the temperature sensor 11c exceeds a predetermined usable temperature (temperature threshold) that is higher than room temperature. The temperature sensor 11c may be attached to the surface of the body of the storage battery 1, for example. Alternatively, the temperature sensor 11c may be incorporated into the monitoring device 10. By attaching the monitoring device 10 to the surface of the body of the storage battery 1, the temperature sensor 11c is also attached to the surface of the body of the storage battery 1.

[0037] The monitoring device 10 may use the temperature sensor 11c to determine whether the temperature of the storage battery 1 is within a predetermined temperature range. That is, if the temperature of the storage battery 1 remains equal to or higher than a first temperature threshold higher than room temperature for a certain period of time, or remains equal to or lower than a second temperature threshold lower than room temperature for a certain period of time, the monitoring device 10 determines that the storage battery 1 is in an inappropriate use state.

[0038] When the storage battery 1 is exposed to high temperatures, its output decreases. This is because the chemical reactions inside the storage battery accelerate. For example, in the case of a lead-acid battery, the electrolytic water evaporates and the concentration increases as the amount of liquid decreases, which accelerates damage due to corrosion at the positive terminal. Therefore, the monitoring device 10 according to this embodiment determines that the storage battery 1 is in an inappropriate state if the high temperature state continues for a long period of time.

[0039] On the other hand, when the temperature of the storage battery 1 is low, the capacity does not decrease, but the energy supply capability decreases. This is because the internal chemical reaction slows down when the temperature of the storage battery drops. It is generally known that a temperature drop of 10°C approximately doubles the time required for a chemical reaction. Therefore, the monitoring device 10 according to this embodiment determines that the storage battery 1 is in an inappropriate use state when the low temperature state continues for a long period of time.

[0040] The allowable temperature range of the storage battery 1 varies depending on the type of storage battery. For example, the temperature range during use for a stationary lead battery is set to -15°C to +40°C, and the temperature range during charging for a lithium ion battery is set to 0°C to 45°C. Therefore, the monitoring device 10 determines whether or not the storage battery is being used inappropriately based on the temperature range set in advance for each storage battery.

[0041] Typically, the charging device 2 is equipped with an overcharge prevention function 2a that stops charging or limits the charging current when it detects an overcharge state. Therefore, if the overcharge prevention function 2a functions properly, the monitoring device 10 according to this embodiment is unnecessary. However, due to a malfunction or abnormal operation of the charging device 2, the overcharge prevention function 2a may not function properly, which may cause deterioration of the storage battery 1. If the deterioration of the storage battery 1 progresses slowly over a long period of time due to occasional abnormal operation of the charging device 2, it is very difficult to prove that the cause is the charging device 2. Overcharging not only shortens the life of the storage battery 1, but also poses the risk of heat generation, fire, explosion, and the like.

[0042] However, the monitoring device 10 according to this embodiment implements an overcharge detection function on the storage battery 1 side in addition to the overcharge prevention function 2a of the charging device 2, so that it is possible to detect an overcharged state of the storage battery 1 due to abnormal operation of the charging device 2, etc., and to investigate the cause of deterioration of the storage battery 1.

[0043] FIG. 3 is a diagram illustrating the operation of the monitoring device 10 during the discharging operation of the storage battery 1. In FIG.

[0044] As shown in Figure 3, when the storage battery 1 is in use, a load 3 is connected to a pair of external terminals 1a and 1b, and power is supplied from the storage battery 1 to the load 3, thereby discharging the storage battery 1. Normally, the load 3 consumes power within its rated range, and may consume a large current depending on the operating conditions.

[0045] The over-discharge state of the storage battery 1 is detected primarily by monitoring a drop in the voltage of the storage battery 1. To detect the over-discharge state, the voltage of the storage battery 1 is periodically measured to check whether it falls below a predetermined threshold voltage (second threshold voltage) that is lower than the rated voltage of the storage battery 1. For example, in the case of a lead-acid battery with a rated voltage of 12 V, the output voltage gradually decreases as the remaining charge decreases, and in an over-discharge state, the output voltage drops to 11 V or less. In an over-discharge state, the discharge current may also drop suddenly, so the over-discharge state can be detected by monitoring the discharge current. The threshold voltage (second threshold voltage) used to detect the over-discharge state is set to an arbitrary value lower than the rated voltage. While the threshold voltage used to detect the over-discharge state is preferably lower than the cut-off voltage, it may also be set to be higher than the cut-off voltage to prioritize protection of the storage battery 1. It can be set arbitrarily according to the operating conditions, taking into account the type of storage battery 1 and the priority of protection. For example, if the end voltage of a lead-acid battery with a rated voltage of 12 V is 10.5 V, the second threshold voltage is preferably lower than 10.5 V, but may be 10.5 V or higher.

[0046] When detecting an over-discharge state, the current value of the storage battery 1 may also be measured, and if the voltage value becomes equal to or less than a predetermined threshold voltage (second threshold voltage) and the current value becomes equal to or greater than a predetermined threshold current (second threshold current), the storage battery 1 may be determined to be in an over-discharge state. The threshold current in this case may be, for example, 1 A, and may be set or changed as desired. By using not only the voltage value but also the current value to determine whether or not the storage battery 1 is in an over-discharge state, the accuracy of determining the over-discharge state can be improved.

[0047] If the storage battery 1 is not used or charged for a long period of time, it will self-discharge and enter an over-discharge state. In an over-discharge state, even if the storage battery's capacity reaches a reference value, continuing to discharge accelerates chemical reactions inside the battery, causing the storage battery 1 to deteriorate. In particular, if a lead-acid battery is in an over-discharge state for a long period of time, lead sulfate will adhere to the electrode plates, causing sulfation. Sulfation can cause a decrease in the capacity of the lead-acid battery and lead to charging problems.

[0048] Normally, if the storage battery 1 is charged periodically and the load 3 always operates correctly, the monitoring device 10 according to this embodiment is not necessary. However, the storage battery 1 may enter an over-discharge state due to insufficient charge of the storage battery 1 or a malfunction or abnormal operation of the load 3.

[0049] However, the monitoring device 10 according to this embodiment is equipped with an over-discharge detection function on the storage battery 1 side, so that it is possible to detect an over-discharge state of the storage battery 1 due to abnormal operation of the load 3, etc., and to investigate the cause of deterioration of the storage battery 1.

[0050] As described above, the monitoring results (data log) of the storage battery 1 by the monitoring device 10 are recorded in the recording unit 13. An external device 5 such as a smartphone can perform data communication with the monitoring device 10 and read the data log. Therefore, when deterioration of the storage battery 1 occurs, the data log can be analyzed to verify the cause of the deterioration of the storage battery 1.

[0051] FIG. 4 is a flowchart showing a method for monitoring the storage battery 1 using the monitoring device 10 according to this embodiment.

[0052] 4, the monitoring device 10 measures the voltage value V and current value I of the storage battery 1 at regular intervals (e.g., every 1 second) and estimates the state of charge of the storage battery 1 (step S11). Next, based on the measurement results, it determines whether the storage battery 1 is in an inappropriate use state (step S12). An inappropriate use state is a use state that leads to deterioration of the storage battery 1, and particularly refers to an overcharged state, an overdischarged state, or a state where the storage battery has not been used for a long time. If an inappropriate use state is detected, the details of the inappropriate use state, as well as the start date and time and the end date and time, are recorded in the recording unit 13 as a data log (steps S12Y and S13).

[0053] In this embodiment, the recording unit 13 does not record all voltage and current values ​​measured by the measuring unit 11, but records the voltage and current values ​​when the inappropriate use state starts / ends, along with the date and time of the start / end. This allows necessary information to be recorded with a small memory capacity, achieving low power consumption and low cost. The recording unit 13 may also record intermediate voltage and current values ​​between the start and end dates / times of the appropriate use state, along with the measurement date and time, as a data log, within the limits of its memory capacity. This allows detailed recording of changes in the output of the storage battery 1 over time.

[0054] When a data log request is received from the external device 5 (step S14Y), the monitoring device 10 starts communication with the external device 5 (step S15) and transmits the data log to the external device 5 (step S16). Therefore, the external device 5 can display the data log and check when the improper use state of the storage battery 1 occurred and when it ended. This makes it possible to determine whether the deterioration of the storage battery 1 is caused by an external factor or by the storage battery itself.

[0055] FIG. 5 is a flowchart illustrating an example of a method for determining whether the storage battery 1 is in an overcharged state.

[0056] As shown in FIG. 5, to determine whether or not the battery is in an overcharged state, the voltage value V and current value I of the battery 1 are measured at regular intervals (for example, every 1 second) (step S101), and the state of charge SOC of the battery 1 is calculated from the measurement results.

[0057] Next, it is determined whether the storage battery 1 is in an overcharged state based on the voltage value V and current value I of the storage battery 1. Specifically, when the voltage value V of the storage battery 1 is equal to or higher than a first threshold voltage V that is higher than the rated voltage of the storage battery 1, the TH1 (For example, the charging voltage of a 12V lead-acid battery is 14.4V) or more, and the current value I of the storage battery 1 exceeds the first threshold current I TH1 (for example, 0.1 A) or more, it is determined that the storage battery 1 is in an overcharged state. TH1 and the first threshold current I TH1can be set arbitrarily depending on the type of storage battery. When the overcharged state of the storage battery 1 is detected, the time counter starts measuring time (step S103).

[0058] Thereafter, the measurement of the voltage value V and the current value I of the storage battery 1 and the calculation of the charging rate continue (step S104). TH1 or the current value I falls below the first threshold current I TH1 If the voltage drops below 0V, it is determined that the overcharged state has ended (step S105Y). When the end of the overcharged state of the storage battery 1 is detected, the time measurement by the time counter ends (step S106).

[0059] Next, the duration of the overcharge state is evaluated, and if the counting period by the time counter is equal to or exceeds a first threshold period (e.g., three months or more), it is determined that the storage battery 1 is being used in an inappropriate manner that could lead to deterioration (steps S107Y and S108), and the start and end dates and times of the time counter are recorded as the start and end dates and times of the overcharge state (step S109). Furthermore, the voltage value V and current value I at the start date and time of the overcharge state, and the voltage value V and current value I at the end date and time of the overcharge state, are recorded along with the start date and time and the end date and time of the overdischarge state. The time counter is then reset, and the series of operations is terminated (step S110).

[0060] FIG. 6 is a flowchart illustrating an example of a method for determining whether the storage battery 1 is in an over-discharged state.

[0061] As shown in FIG. 6, to determine whether or not the storage battery 1 is in an over-discharge state, the voltage value V and current value I of the storage battery 1 are measured at regular intervals (for example, every 1 second) (step S201).

[0062] Next, it is determined whether the storage battery 1 is in an over-discharge state based on the voltage value V and current value I of the storage battery 1 (step S202). Specifically, when the voltage value V of the storage battery 1 is equal to a second threshold voltage V that is lower than the rated voltage of the storage battery 1, TH2 or less, and the current value I of the storage battery 1 is equal to or less than the second threshold current I TH2(for example, 0.1 A) or more, it is determined that the storage battery 1 is in an over-discharge state. For example, if the lead-acid battery manufacturer specifies the end voltage of a lead-acid battery with a rated voltage of 12 V as 10.5 V, then the second threshold voltage V TH2 It is preferable that the second threshold voltage V is set to a value lower than the end voltage (for example, 10.3 V), but it may be set to a value equal to or higher than the end voltage (for example, 10.7 V) to prioritize protection of the lead-acid battery. TH2 and the second threshold current I TH2 can be set arbitrarily depending on the type of storage battery. When an over-discharge state of the storage battery 1 is detected, time measurement by the time counter is started (step S203).

[0063] Thereafter, measurement of the voltage value V and the current value I of the storage battery 1 continues (step S204). Then, when the voltage value V of the storage battery 1 returns to a predetermined voltage equal to or higher than the cut-off voltage (preferably equal to or higher than the rated voltage) due to the storage battery 1 being charged, it is determined that the over-discharge state has ended (step S205Y). When the end of the over-discharge state of the storage battery 1 is detected, the time measurement by the time counter ends (step S206).

[0064] Next, the duration of the over-discharge state is evaluated, and if the count period by the time counter is equal to or exceeds a second threshold period (e.g., one day or more), it is determined that the state corresponds to an inappropriate use state that may lead to deterioration of the storage battery 1 (steps S207Y and S208), and the start and end dates and times of the time counter are recorded as the start and end dates and times of the over-discharge state, respectively (step S209). In addition, the voltage value V and current value I at the start date and time of the over-discharge state, and the voltage value V and current value I at the end date and time of the over-discharge state, are recorded together with the start date and time and the end date and time of the over-discharge state. Thereafter, the time counter is reset, and the series of operations is terminated (step S210).

[0065] FIG. 7 is a flowchart illustrating another example of a method for determining whether the storage battery 1 is in an over-discharged state.

[0066] As shown in FIG. 7, to determine whether or not the storage battery 1 is in an over-discharge state, the voltage value V and current value I of the storage battery 1 are measured at regular intervals (for example, every 1 second) (step S201).

[0067] Next, it is determined whether the storage battery 1 is in an over-discharge state based on the voltage value V and current value I of the storage battery 1 (step S202). Specifically, when the voltage value V of the storage battery 1 is equal to a second threshold voltage V that is lower than the rated voltage of the storage battery 1, TH2 or less, and the current value I of the storage battery 1 is equal to or less than the second threshold current I TH2 If the current is equal to or greater than (for example, 1 A), it is determined that the storage battery 1 is in an over-discharge state (step S211).

[0068] If it is determined that the storage battery 1 is in an over-discharge state, the monitoring device 10 records the start date and time of the over-discharge state as the start date and time of the inappropriate use state, and also records the voltage value V and current value I at the start date and time of the over-discharge state together with the start date and time of the over-discharge state (steps S211, S212).

[0069] Thereafter, the monitoring device 10 is automatically stopped, and the operation of measuring the voltage value V and the current value I of the storage battery 1 is also stopped (step S213). By stopping the operation of the monitoring device 10, the consumption of the storage battery 1 can be suppressed, and a shortening of the lifespan of the storage battery 1 can be prevented.

[0070] Next, when the voltage value V of the storage battery 1 returns to a predetermined voltage equal to or higher than the end voltage (preferably equal to or higher than the rated voltage) due to the storage battery 1 being charged, the power supply unit 16 of the monitoring device 10 starts up and the monitoring device 10 automatically starts up, thereby resuming the measurement operation of the voltage value V and current value I of the storage battery 1 (steps S214Y, S215).

[0071] Next, the monitoring device 10 determines that the over-discharge state of the storage battery 1 has ended, and records the end date and time of the over-discharge state as the start date and time of the inappropriate use state, and also records the voltage value V and the current value I at the end date and time of the over-discharge state together with the end date and time of the over-discharge state (step S216). This completes the series of operations of the monitoring device 10 related to determining the over-discharge state of the storage battery 1.

[0072] FIG. 8 is a flowchart illustrating an example of a method for determining whether the storage battery 1 has been unused for a long period of time.

[0073] As shown in FIG. 8, to determine whether or not the storage battery 1 has not been used for a long period of time, the current value I of the storage battery 1 is measured at regular intervals (for example, every 1 second) (step S301).

[0074] Next, it is determined whether the storage battery 1 is in an unused state based on the current value I of the storage battery 1. Specifically, when the current value I of the storage battery 1 is equal to or lower than the third threshold current I TH3 (for example, 0.1 A) or less, it is determined that the unused state of the storage battery 1 has occurred (step S302Y). TH3 can be set arbitrarily depending on the type of storage battery. When it is detected that the storage battery 1 is in an unused state, the time counter starts measuring time (step S303).

[0075] Thereafter, the measurement of the current value I of the storage battery 1 continues (step S304). Then, when the current value I reaches the third threshold current I TH3 If the time exceeds the time limit, it is determined that the unused state has ended (step S305Y). When the end of the unused state of the storage battery 1 is detected, the time measurement by the time counter ends (step S306).

[0076] Next, the duration of the unused state is evaluated, and if the count period by the time counter is equal to or exceeds a third threshold period (e.g., one month or more), it is determined that the state corresponds to an inappropriate use state that may lead to deterioration of the storage battery 1 (steps S307Y and S308), and the start and end dates and times of the time counter measurement are recorded as the start and end dates and times of the long-term unused state, respectively (step S309). In addition, the voltage value V and current value I at the start date and time of the long-term unused state and the voltage value V and current value I at the end date and time of the long-term unused state are recorded together with the start date and time and end date and time of the long-term unused state. Thereafter, the time counter is reset, and the series of operations ends (step S310).

[0077] As described above, the monitoring device 10 for the storage battery 1 according to this embodiment includes a measurement unit 11 that measures the voltage value V and current value I of the storage battery 1, a determination unit 12 that determines whether the storage battery 1 is in an improper use state, and a recording unit 13 that records the start date and time and the end date and time of the improper use state as a data log. This makes it possible to evaluate whether the charging and discharging operations of the storage battery 1 are being performed correctly and to objectively determine whether the deterioration of the storage battery 1 is due to the storage battery itself or an external factor such as a charging device. Therefore, the cause of the deterioration of the storage battery 1 can be determined.

[0078] FIG. 9 is a block diagram that schematically shows the configuration of a storage battery system 1S to which a monitoring device 10 for a storage battery 1 according to this embodiment is applied.

[0079] As shown in FIG. 9, a storage battery system 1S according to this embodiment includes a battery pack 7 consisting of a plurality (four in this example) of storage battery units 1-1 to 1-4 connected in series, and a load 3 is connected to the battery pack 7. For example, if the rated voltage of one storage battery unit 1 is 12 V, a voltage of 12 × 4 = 48 V is applied to the load 3. When charging the battery pack 7, a charging voltage exceeding 48 V is applied to a pair of external terminals 7a, 7b of the battery pack 7, and the four series-connected storage battery units 1-1 to 1-4 are simultaneously charged. The battery system may have a configuration in which a plurality of storage battery units are connected in parallel, or may have a combination of series and parallel connections.

[0080] In this combination of four storage battery units 1-1 to 1-4, a monitoring device 10 according to this embodiment is provided for each storage battery 1 and connected to each storage battery unit individually. That is, a first monitoring device 10-1 is connected to the pair of external terminals 1a, 1b of the first storage battery unit 1-1, a second monitoring device 10-2 is connected to the pair of external terminals 1a, 1b of the second storage battery unit 1-2, a third monitoring device 10-3 is connected to the pair of external terminals 1a, 1b of the third storage battery unit 1-3, and a fourth monitoring device 10-4 is connected to the pair of external terminals 1a, 1b of the fourth storage battery unit 1-4.

[0081] When a charging device is connected to a pair of external terminals 7a, 7b of the battery pack 7 to simultaneously charge the four battery units 1-1 to 1-4, an imbalance in charging voltages may cause a specific battery unit to become overcharged. However, in this embodiment, a monitoring device 10 is provided for each of the multiple battery units 1, so it is possible to individually check which battery unit 1 has become overcharged and to verify whether the cause of the overcharge is the battery itself or something other than the battery, such as the charging device. It is also possible to individually check which battery unit 1 has become overdischarged.

[0082] FIG. 10 is a block diagram that schematically shows another configuration of a storage battery system 1S to which the monitoring device 10 for the storage battery 1 according to this embodiment is applied.

[0083] As shown in FIG. 10, the battery system according to this embodiment includes a battery pack 7 consisting of a plurality (24 in this example) of battery units 1-1 to 1-24 connected in series, and a load 3 is connected to a pair of external terminals 7a, 7b of the battery pack 7. For example, if the rated voltage of one battery unit 1 is 2V, a voltage of 2×24=48V is applied to the load 3. When charging the battery pack 7, a charging voltage exceeding 48V is applied to the pair of external terminals 7a, 7b of the battery pack 7, and the 24 battery units 1-1 to 1-24 connected in series are simultaneously charged. The battery system may have a configuration in which a plurality of battery units are connected in parallel, or may have a combination of series and parallel connections.

[0084] In the battery pack 7, which is a combination of 24 storage battery units 1-1 to 1-24, the 24 storage battery units 1-1 to 1-24 are divided into four storage battery groups 8-1 to 8-4. A monitoring device 10 according to this embodiment is provided for each group and connected to each of the four storage battery groups 8-1 to 8-4. That is, a first monitoring device 10-1 is connected to a pair of external terminals 8a, 8b of a first storage battery group 8-1 consisting of storage battery units 1-1 to 1-6, a second monitoring device 10-2 is connected to a pair of external terminals 8a, 8b of a second storage battery group 8-2 consisting of storage battery units 1-7 to 1-12, a third monitoring device 10-3 is connected to a pair of external terminals 8a, 8b of a third storage battery group 8-3 consisting of storage battery units 1-13 to 1-18, and a fourth monitoring device 10-4 is connected to a pair of external terminals 8a, 8b of a fourth storage battery group 8-4 consisting of storage battery units 1-19 to 1-24.

[0085] When a charging device is connected to a pair of external terminals 7a, 7b of the battery pack 7 to simultaneously charge the four battery groups 8-1 to 8-4, an imbalance in charging voltages may cause a specific battery unit to become overcharged. However, in this embodiment, a monitoring device 10 is provided for each of the four battery groups 8-1 to 8-4, making it possible to individually check which battery group has become overcharged and to determine whether the cause of the overcharge is the battery itself or something other than the battery, such as the charging device. It is also possible to individually check which battery group has become overdischarged.

[0086] The above describes a preferred embodiment of the present invention, but the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the present invention, and it goes without saying that these modifications are also included within the scope of the present invention.

[0087] For example, in the above embodiment, the voltage and current values ​​(or temperature measurements) indicating the details of the inappropriate use state are recorded as a data log along with the start date and time and the end date and time, but it is sufficient to record at least the start date and time and the end date and time, and it is also possible to omit recording the voltage and current values ​​(or temperature measurements). Furthermore, either the voltage or the current value may be recorded as the details of the inappropriate use state, or a code indicating the type of inappropriate use state (overcharged state / overdischarged state / long-term unused state) may be recorded. Furthermore, the above-described method of determining the inappropriate use state (overcharged state / overdischarged state / long-term unused state) is merely an example, and various determination methods may be employed. [Explanation of symbols]

[0088] 1. Storage battery 1-1, 1-2, 1-3, 1-4 Battery Unit 1a External terminal (positive) 1b External terminal (negative pole) 1S battery storage system 2 Charging device 2a Overcharge prevention function 3. Load 5 External device 7 Battery pack 7a,7b External terminal 8-1, 8-2, 8-3, 8-4 Battery Group 8a, 8b external terminals 10,10-1,10-2,10-3,10-4 Monitoring device 11 Measuring part 11a input terminal 11b input terminal 11c Temperature Sensor 12 Judgment section 12a Overcharge state determination unit 12b Over-discharge state determination unit 12c Long-term unused status determination section 13 Recording section 14 Display section 15 Communications Department 16 Power supply section

Claims

1. a measurement unit that measures a voltage value and a current value between a pair of external terminals of a storage battery; a determination unit that determines an inappropriate use state of the storage battery based on the voltage value and the current value of the storage battery measured by the measurement unit; and a recording unit that records the start date and time and the end date and time of the inappropriate use state as a data log, the inappropriate use state includes an overcharged state or an overdischarged state of the storage battery; the determination unit determines that the storage battery is in the overcharged state when the voltage value becomes equal to or greater than a first threshold voltage that is higher than a rated voltage of the storage battery and the duration of a state in which the current value is equal to or greater than the first threshold current becomes equal to or greater than a first threshold period; The determination unit determines that the battery is in an over-discharge state when the voltage value becomes equal to or lower than a second threshold voltage that is lower than the rated voltage of the battery, and the duration of the state in which the current value is equal to or higher than the second threshold current becomes equal to or longer than the second threshold period.

2. The determination unit determines that the battery is in the over-discharge state when the voltage value is equal to or lower than a second threshold voltage that is lower than the rated voltage of the battery, and the current value is equal to or higher than a second threshold current; When it is determined that the storage battery is in the over-discharged state, the date and time when the over-discharged state started and the voltage value and current value at that time are recorded as the data log, and then the measurement unit stops measuring the voltage value and current value of the storage battery; The monitoring device of claim 1, wherein when the over-discharge state of the storage battery ends, the measurement unit resumes measuring the voltage and current values ​​of the storage battery, and records the date and time when the over-discharge state ends and the voltage and current values ​​at that time as the data log.

3. Further, a temperature sensor is provided to measure the temperature of the storage battery. the determination unit determines that the device is in the inappropriate use state when the temperature measured by the temperature sensor is equal to or greater than a first temperature threshold value that is higher than an usable temperature or equal to or less than a second temperature threshold value that is lower than room temperature, The monitoring device according to claim 1 , wherein the recording unit further records the temperature measurement value at the start date and time of the inappropriate use state and the temperature measurement value at the end date and time of the inappropriate use state as the data log.

4. The monitoring device according to claim 1 , wherein the monitoring device is integrated into the main body of the storage battery or is detachable.

5. The monitoring device according to claim 1, wherein the monitoring device monitors a storage battery group consisting of a plurality of storage battery units connected in series or in parallel, or a combination thereof, and the measurement unit is connected to a pair of external terminals of the storage battery group.

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