JP7444846B2 - Rechargeable battery fluid loss detection device and rechargeable battery fluid loss detection method - Google Patents

Description

The present invention relates to a rechargeable battery fluid loss detection device and a rechargeable battery fluid loss detection method.

As a technique for detecting an abnormality in a rechargeable battery, for example, there is a technique disclosed in Patent Document 1.

Patent Document 1 describes a remaining capacity measurement method in which the specific gravity of an electrolyte is determined from the open circuit voltage of a lead-acid battery and the remaining capacity is estimated from the specific gravity of the electrolyte. A technique has been disclosed in which the remaining capacity is determined by determining the spatial volume within the battery at a given time, and correcting the electrolyte specific gravity determined from the open circuit voltage by the amount of electrolyte solution determined from the difference in these volumes.

Japanese Patent Application Publication No. 09-211090

By the way, in the technique disclosed in Patent Document 1, in order to estimate the amount of liquid loss from the specific gravity of the electrolyte, it is necessary to measure the volume of the lead-acid battery to be measured in advance and investigate the relationship between the amount of liquid loss and specific gravity. There is. For this reason, there is a problem in that it is difficult to accommodate lead-acid batteries of different capacities.

The present invention has been made in view of the above circumstances, and provides a rechargeable battery fluid loss detection device and a rechargeable battery fluid loss detection method that are capable of detecting fluid loss in various rechargeable batteries. It is intended to.

In order to solve the above-mentioned problems, the present invention provides a rechargeable battery fluid loss detection device that detects fluid loss of electrolyte of a rechargeable battery, including a identifying means for identifying the open circuit voltage of the rechargeable battery, and a When the charging rate of the rechargeable battery is a predetermined value and the open circuit voltage identified by the identifying means is greater than a predetermined threshold, abnormal liquid loss has occurred in the electrolyte of the rechargeable battery. The present invention is characterized by comprising a determining means for determining that there is a presence, and a presenting means for presenting the determination result of the determining means.
According to such a configuration, it becomes possible to detect fluid loss in various rechargeable batteries.

Further, in the present invention, when the charging rate of the rechargeable battery is a full charge and the open circuit voltage specified by the specifying means is larger than a predetermined threshold value, the determining means determines whether the charging It is characterized in that it is determined that the abnormal liquid loss has occurred in the electrolyte of the battery.
According to such a configuration, since full charge can be detected relatively easily, abnormal liquid reduction can be reliably detected using the time of full charge as a reference.

Further, in the present invention, the determining means determines that a difference value between the open circuit voltage specified by the specifying means and the open circuit voltage when the rechargeable battery is new, when it is replaced, or when the rechargeable battery is replaced is determined by a predetermined value. is larger than a threshold value, it is determined that the abnormal liquid loss has occurred in the electrolytic solution of the rechargeable battery.
According to such a configuration, even if rechargeable batteries have different characteristics, abnormal fluid loss can be reliably detected without being influenced by individual differences.

Further, the present invention is characterized in that it includes a correction means for correcting the open circuit voltage specified by the identification means in accordance with the temperature of the electrolytic solution or the temperature around the rechargeable battery.
According to such a configuration, abnormal liquid reduction can be reliably detected by reducing the influence of temperature.

Further, the present invention includes calculation means for calculating a value of internal resistance of the rechargeable battery, and the determination means is configured to determine that the value of the increase rate of the internal resistance over a certain period of time calculated by the calculation means is a predetermined value. If the rechargeable battery is larger than a threshold value, it is determined that the electrode plates of the rechargeable battery are exposed from the electrolyte.
According to such a configuration, it is possible to detect that the electrode plate is exposed from the electrolyte due to abnormal liquid reduction due to electrolyte leakage caused by damage to the battery case or the like.

The present invention also provides a rechargeable battery fluid loss detection method for detecting fluid loss of electrolyte in a rechargeable battery, including a measuring step of measuring an open circuit voltage of the rechargeable battery, and a charging rate of the rechargeable battery. If the open circuit voltage measured in the measuring step is larger than a predetermined threshold when the value is a predetermined value, a determining step of determining that abnormal liquid reduction has occurred in the electrolyte of the rechargeable battery; , and a presentation step of presenting the determination result of the determination step.
According to such a method, it becomes possible to detect fluid loss in various rechargeable batteries.

According to the present invention, it is possible to provide a rechargeable battery fluid loss detection device and a rechargeable battery fluid loss detection method that are capable of detecting fluid loss in various rechargeable batteries.

1 is a diagram illustrating a configuration example of a rechargeable battery liquid loss detection device according to an embodiment of the present invention. FIG. 2 is a block diagram showing a detailed configuration example of a control section in FIG. 1. FIG. FIG. 3 is a diagram showing the relationship between the liquid level height of an electrolytic solution and OCV. FIG. 3 is a diagram showing the relationship between the amount of electrolytic solution reduction (exposure rate of electrode plates) and the rate of increase in internal resistance. FIG. 3 is a diagram showing a method for measuring internal resistance. 2 is a flowchart showing an example of a process executed in the embodiment shown in FIG. 1. FIG. 2 is a flowchart showing an example of other processing executed in the embodiment shown in FIG. 1. FIG.

Next, embodiments of the present invention will be described.

(A) Description of the configuration of the embodiment of the present invention FIG. 1 is a diagram showing a power supply system of a vehicle having a rechargeable battery liquid loss detection device according to an embodiment of the present invention. In this figure, a rechargeable battery liquid loss detection device 1 has a control unit 10, a voltage sensor 11, a current sensor 12, and a temperature sensor 13 as main components, and detects the occurrence of abnormality inside a rechargeable battery 14. To detect. Note that the configuration may be such that the temperature sensor 13 is not included.

Here, the control unit 10 refers to outputs from the voltage sensor 11, current sensor 12, and temperature sensor 13, detects the state of the rechargeable battery 14, and controls the generated voltage of the alternator 15 to charge the battery. The state of charge of the battery 14 is controlled. Voltage sensor 11 detects the terminal voltage of rechargeable battery 14 and notifies control unit 10 of the detected terminal voltage. Current sensor 12 detects the current flowing through rechargeable battery 14 and notifies control unit 10 of the current. The temperature sensor 13 detects the temperature of the electrolyte of the rechargeable battery 14 or the temperature around the rechargeable battery 14 and notifies the control unit 10 of the temperature. Note that instead of the control unit 10 controlling the charging state of the rechargeable battery 14 by controlling the generated voltage of the alternator 15, for example, an ECU (Electric Control Unit) (not shown) may control the charging state. good.

The rechargeable battery 14 is constituted by a rechargeable battery having an electrolytic solution, such as a lead-acid battery, a nickel-cadmium battery, or a nickel-metal hydride battery, and is charged by the alternator 15 to drive the starter motor 17 to start the engine. At the same time, power is supplied to the load 18. Note that the rechargeable battery 14 is configured by connecting a plurality of cells in series. Alternator 15 is driven by engine 16 , generates alternating current power, converts it into direct current power through a rectifier circuit, and charges rechargeable battery 14 . The alternator 15 is controlled by the control unit 10 and is capable of adjusting the generated voltage.

The engine 16 is configured by, for example, a reciprocating engine or a rotary engine such as a gasoline engine or a diesel engine, and is started by a starter motor 17 and drives the drive wheels via a transmission to provide propulsive force to the vehicle. to generate electricity. The starter motor 17 is configured by, for example, a DC motor, generates rotational force using electric power supplied from the rechargeable battery 14, and starts the engine 16. The load 18 includes, for example, an electric steering motor, a defogger, a seat heater, an ignition coil, a car audio system, a car navigation system, and the like, and is operated by electric power supplied from the rechargeable battery 14 .

FIG. 2 is a diagram showing a detailed configuration example of the control section 10 shown in FIG. 1. As shown in FIG. As shown in this figure, the control unit 10 includes a CPU (Central Processing Unit) 10a, a ROM (Read Only Memory) 10b, a RAM (Random Access Memory) 10c, a communication unit 10d, an I/F (Interface) 10e, and It has a bus 10f. Here, the CPU 10a controls each section based on a program 10ba stored in the ROM 10b. The ROM 10b is composed of a semiconductor memory or the like, and stores a program 10ba and the like. The RAM 10c is constituted by a semiconductor memory or the like, and stores data generated when executing the program 10ba and data 10ca such as a table to be described later. The communication unit 10d communicates with an ECU (Electronic Control Unit), which is a higher-level device, and notifies the higher-level device of detected information or control information. The I/F 10e converts signals supplied from the voltage sensor 11, current sensor 12, and temperature sensor 13 into digital signals and takes them in, and also supplies drive current to the alternator 15, starter motor 17, etc. control. The bus 10f is a group of signal lines that connects the CPU 10a, ROM 10b, RAM 10c, communication unit 10d, and I/F 10e to each other and enables information to be exchanged between them.

(B) Description of operation of embodiment of the present invention Next, operation of the embodiment of the present invention will be explained. Note that, after explaining the operating principle of the embodiment of the present invention, the detailed operation will be explained below.

First, the operating principle of the embodiment of the present invention will be explained. In the embodiment of the present invention, a decrease in electrolyte solution is detected based on the OCV (Open Circuit Voltage) of the rechargeable battery 14. FIG. 3 is a diagram showing the relationship between the liquid level of the electrolyte of the rechargeable battery 14 and the OCV (V) when the charging rate SOC is 100%. As the liquid reduction progresses, the electrolyte level changes from the Upper Line (the line indicating the appropriate upper limit of the electrolyte) to the Lower Line (the line indicating the appropriate lower limit of the electrolyte) near the top of the electrode plate. There is.

In the example of FIG. 3, hatched diamonds indicate measurement results. Further, the horizontal broken line indicates the OCV when new and the OCV when the liquid is abnormally reduced from the bottom. As shown in FIG. 3, OCV increases as liquid reduction progresses.

Figure 4 shows the internal resistance increase with respect to the exposure rate of the electrode plate (height from the top surface of the electrode plate to the liquid level, that is, the value obtained by dividing the exposed height of the electrode plate by the height of the entire electrode plate x 100) (%). It is a figure showing the relationship between the ratio (the value obtained by dividing the amount of change from the internal resistance value before liquid reduction by the internal resistance value before liquid reduction x 100) (%). As shown in FIG. 4, the internal resistance increases as the exposed area of the electrode plate increases as the electrolyte decreases. Note that the internal resistance increase rate (%) shown by the solid line in Figure 4 is the increase rate in an abnormal liquid reduction state where about 40% of the electrode plate is exposed. may be exposed from the electrolyte. Furthermore, by confirming that such a change occurs within a certain period of time, it is possible to confirm that the electrode plate has been exposed due to electrolyte leakage. Further, one of the characteristics is that an increase in internal resistance value caused by liquid loss due to liquid leakage occurs even when no charge/discharge reaction is taking place. Therefore, even when the vehicle is stopped, an abnormal liquid reduction state can be detected with high accuracy based on, for example, a change in the internal resistance value calculated by applying periodic discharge pulses. In addition, the index used for determination using internal resistance is not necessarily the rate of increase in internal resistance, but also the amount of change in internal resistance (absolute value), which detects the state in which the internal resistance value changes within a certain period of time. Other indicators can be used as long as they can be used. The certain period of time can be set to an appropriate amount of time, such as 30 minutes or 1 hour, during which the liquid must be reduced until the electrode plate is exposed due to liquid leakage.

Therefore, in this embodiment, the OCV at the time of abnormal liquid reduction shown by the broken line in FIG. 3 is set as the threshold value Th1, and the internal resistance increase rate at the time of abnormal liquid reduction shown by the solid line in FIG. 4 is set as the threshold value Th2. Then, when the charging rate SOC becomes 100% (fully charged state), the open circuit voltage OCV is measured, and if OCV>Th1, it is determined that abnormal liquid reduction has occurred. Further, the internal resistance R is calculated, and if the internal resistance increase rate>Th2, it is determined that there is a possibility that the electrode plate is exposed to the outside from the electrolytic solution. According to such a means, it is possible to detect even a liquid reduction that does not involve a change in OCV, that is, an abnormal liquid reduction due to liquid leakage or the like that does not cause a change in the concentration of the electrolytic solution.

More specifically, when the rechargeable battery 14 is in a stable state (for example, when several hours have passed since the engine 16 was stopped), the control unit 10 of the rechargeable battery liquid loss detection device 1 controls the voltage The sensor 11 measures the open circuit voltage OCV.

Next, the control unit 10 measures the ambient temperature of the rechargeable battery 14 with reference to the output of the temperature sensor 13, and estimates the temperature of the electrolytic solution from the obtained ambient temperature. Then, based on the temperature of the obtained electrolytic solution, temperature correction is performed so that the open circuit voltage OCV becomes the open circuit voltage OCV at a reference temperature (for example, 25° C.). For example, a table showing the relationship between the temperature of the electrolytic solution and the open circuit voltage OCV is prepared, and the open circuit voltage OCV at the reference temperature is corrected based on the table.

Next, the control unit 10 calculates the charging rate SOC based on the relationship between the open circuit voltage OCV and the charging rate SOC. For example, a table showing the relationship between open circuit voltage OCV and charging rate SOC is prepared, and charging rate SOC is calculated from open circuit voltage OCV based on the table.

Next, the control unit 10 refers to the charging rate SOC to determine whether the rechargeable battery 14 is in a fully charged state, and if it is in a fully charged state, the open circuit voltage OCV is set to a predetermined threshold Th1 ( For example, it is determined whether the OCV value is larger than the OCV value at the time of abnormal liquid reduction shown in FIG.

Next, the control unit 10 calculates the internal resistance R of the rechargeable battery 14. FIG. 5(A) is a diagram showing changes in voltage and current of the rechargeable battery 14. Note that in FIG. 5(A), the horizontal axis indicates elapsed time (s) from the start of measurement, and the vertical axis indicates voltage (V) and current (A). FIG. 5(B) is an enlarged view of a part of FIG. 5(A). In this embodiment, for example, the changing voltage ΔV and changing current ΔI are measured every 1 ms, and cumulatively added over a period of 10 seconds to obtain ΔVa and ΔIa. From these values, the internal Calculate the value of resistance R (=ΔVa/ΔIa).

Next, the control unit 10 determines whether the internal resistance increase rate within a certain period of time is larger than a predetermined threshold Th2 (for example, the value of the internal resistance increase rate during a certain period of time during abnormal liquid reduction shown in FIG. 4). If it is large, it is determined that there is a possibility that the electrode plate is exposed from the electrolyte, and the higher-level device is notified.

According to the above process, by comparing the open circuit voltage OCV at full charge with the threshold Th1, it is possible to easily detect the possibility of liquid reduction, and also to compare the internal resistance increase rate and the threshold Th2. By comparing the results, it is possible to detect whether or not the electrode plate is exposed to the electrolyte. Further, in the above process, since it is not necessary to know the volume of the electrolyte in the rechargeable battery 14, it is possible to detect a decrease in the electrolyte in various types of rechargeable batteries 14.

Next, detailed operation of the embodiment of the present invention will be described with reference to FIG. When the process of the flowchart shown in FIG. 6 is started, the following steps are executed.

In step S10, the CPU 10a of the control unit 10 determines whether or not the rechargeable battery 14 is in a stable state. If it is determined that the rechargeable battery 14 is in a stable state (step S10: Y), the process proceeds to step S11; otherwise (step At S10:N), the process ends. For example, if several hours have passed since the engine 16 was stopped and polarization and stratification have been eliminated, the determination is Y and the process proceeds to step S11.

In step S11, the CPU 10a refers to the output of the voltage sensor 11 and measures the open circuit voltage OCV of the rechargeable battery 14.

In step S12, the CPU 10a estimates the temperature of the electrolyte. More specifically, the CPU 10a measures the ambient temperature of the rechargeable battery 14 with reference to the output of the temperature sensor 13, and estimates the electrolyte temperature from the ambient temperature. As an estimation method, for example, a thermal equivalent circuit (a circuit consisting of thermal resistance, heat capacity, etc.) of the rechargeable battery 14 is obtained, and when the ambient temperature is applied as a voltage to this thermal equivalent circuit, the temperature of the electrolyte is The temperature of the electrolyte can be estimated by determining the output.

In step S13, the CPU 10a temperature-corrects the open circuit voltage OCV measured in step S11 based on the electrolyte temperature determined in step S12. More specifically, the CPU 10a determines the open circuit voltage OCV when the electrolyte temperature estimated in step S12 is the reference temperature of 25°C.

In step S14, the CPU 10a calculates the charging rate SOC from the open circuit voltage OCV temperature-corrected in step S13. More specifically, a table showing the relationship between the open circuit voltage OCV and the SOC is stored in advance in the RAM 10c as data 10ca, and the CPU 10a refers to this table to determine the charging rate SOC from the open circuit voltage OCV. can.

In step S15, the CPU 10a refers to the charging rate SOC determined in step S14, and determines whether the state is fully charged (SOC=100%), and if it is determined that the state is fully charged (step S15: If Y), the process advances to step S16, and otherwise (step S15: N), the process ends.

In step S16, the CPU 10a compares the open circuit voltage OCV temperature-corrected in step S13 with a predetermined threshold Th1, and if OCV>Th1 is satisfied (step S16: Y), the process proceeds to step S17; otherwise, (Step S16: N), the process ends. For example, if the open circuit voltage OCV is larger than the OCV at the time of abnormal liquid reduction shown in FIG. 3, the determination is Y and the process proceeds to step S17.

In step S17, the CPU 10a notifies the host device (for example, an ECU, not shown) via the communication unit 10d that abnormal liquid reduction may have occurred.

In step S18, the CPU 10a calculates the internal resistance R of the rechargeable battery 14. More specifically, at a predetermined timing (for example, the timing when the engine 16 is started), the CPU 10a measures the changing voltage ΔV and changing current ΔI every 1 ms, for example, as explained with reference to FIG. Then, for example, ΔVa and ΔIa are cumulatively added over 10 seconds, and from these values, the value of the internal resistance R (=ΔVa/ΔIa) is calculated by ΔVa/ΔIa. Note that 1 ms and 10 seconds are just examples, and times other than these may be set. Further, the value of the internal resistance R may be temperature-corrected to the value at the reference temperature of 25° C. with reference to the electrolyte temperature estimated in step S12.

In step S19, the CPU 10a determines whether the value of the internal resistance increase rate within a certain period of time calculated in step S18 is larger than a predetermined threshold Th2, and if the internal resistance increase rate>Th2 is satisfied (step If S19:Y), the process proceeds to step S20, and otherwise (step S19:N), the process ends. For example, if the value of the internal resistance increase rate is larger than a predetermined threshold value (for example, the internal resistance increase rate at the time of abnormal liquid reduction shown in FIG. 4), the determination is Y and the process proceeds to step S20.

In step S20, the CPU 10a notifies the host device that the electrode plates of the rechargeable battery 14 may be exposed from the electrolyte.

According to the above processing, the above-described operation can be realized.

(C) Description of Modified Embodiments The above embodiments are merely examples, and it goes without saying that the present invention is not limited to only the cases described above. For example, in the above embodiment, in step S16 shown in FIG. 6, the open circuit voltage OCV and a predetermined threshold value (OCV at the time of abnormal liquid reduction shown in FIG. 3) are used to determine whether there is a possibility of abnormal liquid reduction. I decided to compare and judge. However, the open circuit voltage at the initial time (for example, when the rechargeable battery 14 is new) may differ depending on the rechargeable battery 14. Therefore, as shown in FIG. 7, the initial open circuit voltage of the rechargeable battery 14 is stored as OCV0, and the difference between the open circuit voltage OCV at the time of determination and the initial open circuit voltage OCV0 is compared with the threshold Th3. You can do it like this.

More specifically, in the example shown in FIG. 7, compared to FIG. 6, step S16 is excluded, and step S30 and step S31 are added. Since the other parts are the same as those in FIG. 6, the following description will focus on the different parts.

In step S30, the CPU 10a acquires the initial open circuit voltage OCV0 that is measured at the initial stage of the rechargeable battery 14 and stored in the RAM 10c, for example. Note that the initial open circuit voltage OCV0 can be measured when the vehicle is assembled at the factory and the rechargeable battery 14 is installed, and can be stored in the RAM 10c. Alternatively, it can be measured when the rechargeable battery 14 is replaced after shipment from the factory and stored in the RAM 10c.

In step S31, the CPU 10a calculates the difference value (OCV-OCV0) between the open circuit voltage OCV measured in step S11 and subjected to temperature correction in step S13 and the initial open circuit voltage OCV0, and the difference value is determined to be a predetermined value. It is determined whether or not it is larger than a threshold value (Th3), and when it is determined that it is larger (step S31: Y), the process proceeds to step S17, and in other cases (step S31: N), the process ends.

According to the process shown in FIG. 7, it becomes possible to detect abnormal fluid loss in various types of rechargeable batteries 14.

In FIG. 7, the open circuit voltage when the rechargeable battery 14 is new is used as the initial open circuit voltage OCV0. However, for example, when the rechargeable battery 14 is replenished with distilled water, etc. If the fluid is replaced), the open circuit voltage at that time is measured and stored as, for example, the open circuit voltage during fluid replacement OCV1, and in step S31, the determination is made based on the difference value (OCV-OCV1) and the threshold Th4. You may also do so. That is, in this embodiment, the initial time refers to (1) when new, (2) when replaced, (3) when fluid is replaced, etc.

In addition, in the process of step S31 described above, the presence or absence of abnormal liquid reduction was determined based on the difference value (OCV-OCV0) and the threshold value Th3, but the difference value is divided by the initial open circuit voltage OCV0. The determination may be made based on the value (OCV-OCV0)/OCV0 and the threshold Th5. Similarly, the determination may be made based on the value (OCV-OCV1)/OCV1 obtained by dividing the difference value by the open circuit voltage OCV1 during fluid replacement and the threshold Th6.

Further, in the above embodiment, the open circuit voltage is actually measured when the rechargeable battery 14 is stable, but it may be determined based on an estimated value. For example, by using a voltage characteristic equation that can approximate temporal fluctuations in the open circuit voltage, the open circuit voltage of the rechargeable battery 14 when it is stable can be estimated. By using an approximation formula including a high-order (for example, fourth-order or higher) exponential attenuation function as the voltage characteristic formula, it is possible to estimate the time fluctuation of the open circuit voltage with high accuracy.

Further, in the above embodiment, the internal resistance R is referred to in order to detect that the electrode plate is exposed from the electrolyte, but the process in step S16 in FIG. 6 and step S31 in FIG. In addition, the determination may be made with reference to the change in the internal resistance R. For example, the open circuit voltage OCV and internal resistance R may be multiplied by weighting coefficients W1 and W2, respectively, and added, and the resulting value (W1×OCV+W2×R) is compared with the threshold Th7 to make a decision. You may also do so. Of course, OCV in the above formula may be (OCV-OCV0) or (OCV-OCV1), or (OCV-OCV0)/OCV0 or (OCV-OCV1)/OCV1.

Furthermore, in the above embodiments, the measured open circuit voltage OCV is corrected based on the temperature of the electrolytic solution, but in addition to this, for example, changes over time may be taken into account for correction.

Further, in the embodiments described above, abnormal liquid reduction is detected using the open circuit voltage OCV when the rechargeable battery 14 is fully charged. etc.), the determination may be made using the open circuit voltage OCV. Further, whether or not the battery is fully charged does not necessarily need to be measured, and it may be assumed that the battery is fully charged if charging continues for a predetermined period of time or more.

In step S18 of FIGS. 6 and 7, the internal resistance R is determined by the process shown in FIG. 5, but the value of the internal resistance R may be determined by other methods. For example, the voltage and current when current flows through the load may be determined, and the internal resistance may be determined from these voltages and currents. Alternatively, an equivalent circuit of the rechargeable battery 14 may be set, the voltage and current of the rechargeable battery 14 may be measured, and the equivalent circuit may be determined by learning processing based on these voltages and currents.

Furthermore, the flowcharts shown in FIGS. 6 and 7 are just examples, and the present invention is not limited to the processing in these flowcharts.

1 Rechargeable battery fluid loss detection device 10 Control unit 10a CPU
10b ROM
10c RAM
10d Communication department 10e I/F
11 Voltage sensor 12 Current sensor 13 Temperature sensor 14 Rechargeable battery 15 Alternator 16 Engine 17 Starter motor 18 Load

Claims (5)

In a rechargeable battery liquid loss detection device that detects liquid electrolyte loss in a rechargeable battery,
identification means for identifying an open circuit voltage when the charging rate of the rechargeable battery is fully charged;
determining means for determining whether abnormal liquid reduction has occurred in the electrolyte of the rechargeable battery by comparing the open circuit voltage specified by the specifying means with a predetermined threshold;
Presentation means for presenting the determination result of the determination means;
Calculation means for calculating the value of internal resistance of the rechargeable battery;
has
The identifying means identifies an open circuit voltage of the rechargeable battery that has been continuously charged for a predetermined period of time or more as the open circuit voltage at the time of full charge,
The open circuit voltage at the time of full charge is a terminal voltage of the rechargeable battery that does not include an internal resistance component of the rechargeable battery ,
The determining means determines that the electrode plates of the rechargeable battery are exposed from the electrolyte when the rate of increase in the internal resistance over a certain period of time calculated by the calculating means is greater than a predetermined threshold. A rechargeable battery liquid loss detection device characterized by : The determining means determines that the abnormal liquid reduction has occurred in the electrolyte of the rechargeable battery when the open circuit voltage specified by the specifying means is greater than a predetermined threshold.
The rechargeable battery liquid loss detection device according to claim 1. The determining means determines that when a difference value between the open circuit voltage specified by the identifying means and the open circuit voltage when the rechargeable battery is new, when it is replaced, or when fluid is replaced is larger than a predetermined threshold value. determines that the abnormal liquid loss has occurred in the electrolyte of the rechargeable battery;
The rechargeable battery liquid loss detection device according to claim 1. comprising a correction means for correcting the open circuit voltage specified by the identification means according to the temperature of the electrolytic solution or the temperature around the rechargeable battery;
The rechargeable battery fluid loss detection device according to any one of claims 1 to 3. In a rechargeable battery fluid loss detection method for detecting fluid loss of electrolyte in a rechargeable battery,
a measuring step of measuring an open circuit voltage when the charging rate of the rechargeable battery is fully charged;
a determination step of determining whether abnormal liquid reduction has occurred in the electrolyte of the rechargeable battery by comparing the open circuit voltage measured in the measurement step with a predetermined threshold;
a presentation step of presenting the determination result of the determination step;
a calculating step of calculating a value of internal resistance of the rechargeable battery;
has
In the measuring step, the open circuit voltage of the rechargeable battery that has been continuously charged for a predetermined period of time or more is measured as the open circuit voltage at the time of full charge,
The open circuit voltage at the time of full charge is a terminal voltage of the rechargeable battery that does not include an internal resistance component of the rechargeable battery ,
In the determination step, if the rate of increase in the internal resistance over a certain period of time calculated in the calculation step is greater than a predetermined threshold, it is determined that the electrode plate of the rechargeable battery is exposed from the electrolyte. A method for detecting fluid loss in a rechargeable battery, characterized by :

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