WO2012090983A1 - Remaining-capacity measurement device - Google Patents

Abstract

[Problem] To provide a remaining-capacity measurement device in which the need for zero correction, temperature correction, and the like is eliminated by automatic updating of an initial value setting by the remaining-capacity measurement device when measuring remaining capacity, on the basis of a remaining-capacity table that is set for each battery. [Solution] The remaining-capacity measurement device is provided with: a measurement means for measuring remaining capacity data; a recording means that has a pre-set remaining-capacity table and a pre-set upper limit value for remaining battery capacity recorded therein, and records the remaining capacity data measured by the measurement means; and a calculation device for calculating remaining battery capacity on the basis of the remaining capacity data recorded by the recording means. Remaining battery capacity data measured during charge/discharge is consecutively recorded in the recording means. The remaining battery capacity is calculated on the basis of the remaining battery capacity data recorded in the recording means. When battery charging is completed, the upper limit value of the remaining battery capacity is updated using the remaining battery capacity, in the case that the remaining battery capacity exceeds the upper limit value for remaining capacity. When battery discharge is completed, the remaining battery capacity is corrected on the basis of the remaining capacity table.

Description

Remaining capacity measuring device

The present invention relates to a remaining capacity measuring device for measuring (estimating) the remaining capacity of a battery such as a forklift, an electric vehicle, or a hybrid vehicle.

In vehicles using a battery as a power source, such as a forklift, an electric vehicle, and a hybrid vehicle, it is necessary to accurately measure and grasp the remaining capacity of the battery.
Conventionally, in order to perform such remaining capacity measurement, a method of detecting current by using a shunt resistor or a Hall element is known.

In current detection using a shunt resistor, for example, as disclosed in Japanese Patent Application Laid-Open No. 2008-045771, a resistor is provided between the first connection terminal and the second connection terminal. A shunt resistor configured as described above is used. In Patent Document 1, the first connection terminal, the second connection terminal, and the resistor are formed in a washer shape, and the first connection terminal, the second connection terminal, and the resistance are formed using bolts and nuts. The body is fixed together.

Further, in current detection using a Hall element, for example, as disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2007-198904), a core having an annular shape and a gap portion is used. By arranging the Hall element in the gap portion of the core, the Hall element detects a magnetic field corresponding to the magnitude of the current flowing through the current line surrounded by the core, and measures the current.

JP 2008-045771 A JP 2007-198904 A

However, in the current detection method using the Hall element, when used continuously for a long time, the zero point shifts and a measurement error occurs, so that it is difficult to use continuously for a long time. In addition, in current detection using a Hall element, there is a limit to miniaturization of the device. For these reasons, it is impossible to constantly monitor the remaining capacity with high accuracy by attaching the remaining capacity measuring device to a vehicle or the like.

On the other hand, in the current detection method using the shunt resistor, the shunt resistor generates heat. Therefore, it is necessary to perform temperature correction according to the generated heat.
In order to perform such zero point correction and temperature correction, it is usually necessary to correct the remaining capacity meter while the use of the battery is temporarily stopped.

For this reason, in the case of a vehicle that is continuously used, the remaining capacity meter will be distorted without the zero point correction or temperature correction of the remaining capacity meter, and the remaining capacity meter will remain sufficiently on the display. Nevertheless, the power of the vehicle suddenly dropped or stopped.

In addition, when the charge / discharge cycle is continuously used, the battery deteriorates in the course, and the usable capacity of the battery is reduced.
On the other hand, when the battery is refreshed or the usage conditions are improved (for example, when the temperature when the battery is used is changed from low to high), the effective charge increases and the usable capacity increases. Become.

In view of the current situation, the present invention is based on a load voltage-based remaining capacity table determined for each battery, and automatically updates the initial value setting at the time of remaining capacity measurement by the remaining capacity measuring device. It is an object of the present invention to provide a remaining capacity measuring device that does not require zero correction or temperature correction.

The present invention was invented in order to achieve the above-described problems and objects in the prior art, and the remaining capacity measuring device of the present invention is a remaining capacity measuring device for measuring the remaining capacity of a battery. There,
A measuring means for measuring remaining capacity related data;
A storage unit storing a preset remaining capacity table and a preset upper limit value of the remaining capacity of the battery, and storing remaining capacity related data measured by the measuring unit;
An arithmetic device that calculates the remaining capacity of the battery based on the remaining capacity related data stored in the storage means,
The storage means sequentially stores the measured remaining capacity related data of the battery during charging and discharging, and calculates the remaining capacity of the battery based on the remaining capacity related data of the battery stored in the storing means.
At the end of charging of the battery, if the remaining capacity of the battery exceeds the upper limit value of the remaining capacity, the upper limit value of the remaining capacity is updated with the remaining capacity of the battery,
At the end of battery discharge, the remaining battery capacity is corrected based on the remaining capacity table.

Further, the remaining capacity measuring device of the present invention measures the voltage value of the battery by the measuring means when charging the battery, and selects a predetermined charging efficiency coefficient based on the voltage value of the battery,
The remaining capacity of the battery is calculated by the computing means based on the measured battery charging current flowing in the battery and the predetermined charging efficiency coefficient stored in the storage means. To do.

Further, the remaining capacity measuring device of the present invention, when discharging the battery,
The remaining capacity of the battery is calculated by the calculation means based on a measured battery discharge current discharged from the battery and a predetermined discharge efficiency coefficient stored in the storage means. And

The remaining capacity measuring device of the present invention is configured to measure a voltage value of a battery by the measuring means and to select a predetermined discharge efficiency coefficient based on the voltage value of the battery. To do.

The remaining capacity measuring device of the present invention is characterized in that the remaining capacity measuring device includes a display means for displaying at least the remaining capacity of the battery.
Further, the remaining capacity measuring device of the present invention comprises a communication means for the remaining capacity measuring apparatus to communicate with at least one of the display means, an external storage means, and an external computer. It is characterized by.

Further, in the remaining capacity measuring device of the present invention, the battery is provided with an individual identification number for each battery,
The storage means stores remaining capacity related data associated with a battery identification number.

Moreover, the remaining capacity measuring device of the present invention includes the remaining capacity measuring device,
A battery-side terminal for connection to the battery terminal;
An output side terminal constituting the output side terminal, and
The battery side terminal and the output side terminal are respectively plug-in connectors.

In addition, the remaining capacity measuring device of the present invention is configured to output an alarm when the arithmetic device detects a battery abnormality during charging / discharging of the battery.

The remaining capacity measuring device of the present invention is configured to output an alarm when the remaining capacity of the battery falls below a predetermined alarm lower limit value at the time of charge / discharge of the battery. .

According to the present invention, based on the remaining capacity table defined for each battery, the remaining capacity is corrected at the end of the battery discharge, and the upper limit value of the remaining capacity is updated at the end of the battery charging. There is no need to stop using zero correction or temperature correction, and it is possible to use a continuous cycle of battery charging and discharging, and an accurate initial value is set, so highly accurate remaining capacity measurement (estimation) is possible. It can be carried out.

FIG. 1 is a schematic circuit diagram of a remaining capacity measuring apparatus according to the present invention. FIG. 2 is a schematic configuration diagram when the remaining capacity measuring device of FIG. 1 is connected to a battery. FIG. 3 is a schematic configuration diagram illustrating an example of a plug-in connector. FIG. 4 is a schematic configuration diagram when the remaining capacity measuring device of FIG. 1 is connected to an external storage device and a computer by wireless communication. FIG. 5 is a flowchart showing a flow of measuring the remaining capacity during charging / discharging of the battery by the remaining capacity measuring apparatus of the present invention. FIG. 6 is a graph showing the relationship between the battery voltage (V) and the remaining capacity (% capacity) during charging / discharging of the battery, measured by the remaining capacity measuring device of the present invention. FIG. 7 is an example showing an abnormality of the battery, and is a graph showing the relationship between the number of times the battery has been charged and the amount of charge (AH) when only insufficient charging can be performed. FIG. 8 shows an example of battery abnormality, and shows the relationship between the battery charge-discharge amount (AH) and the battery voltage (V) when the battery voltage value suddenly drops when the battery is discharged. It is a graph.

Hereinafter, embodiments (examples) of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a schematic circuit configuration diagram of the remaining capacity measuring device of the present invention, and FIG. 2 is a schematic configuration diagram when the remaining capacity measuring device of FIG. 1 is connected to a battery.

1 and 2, reference numeral 10 generally indicates a remaining capacity measuring apparatus of the present invention.
As shown in FIG. 1, a remaining capacity measuring device 10 of the present invention includes a measuring means 20 including a shunt resistor 22, a storage means 24 for storing measured remaining capacity related data, and a remaining capacity measuring apparatus. 10 for calculating 10 and calculating the remaining capacity, a battery-side positive terminal 12a and a battery-side negative terminal 12b for connecting to the battery 50, an output-side positive terminal 14a for connecting to a vehicle and a charger, The output side negative terminal 14b is provided.

In this embodiment, the end portions of the battery side positive terminal 12a, the battery side negative terminal 12b, the output side positive terminal 14a, and the output side negative terminal 14b are easily connected to the battery 50 and an output side device (not shown), respectively. The plug-in connector 16 as shown in FIG. 3 is provided so that it can be attached to and detached from the connector, but the shape of the terminal is not particularly limited.

The plug-in connector 16 shown in FIG. 3 is configured by connecting the battery-side positive terminal 12a and the battery-side negative terminal 12b (or the output-side positive terminal 14a and the output-side negative terminal 14b) to one connector body 18. Yes.

A battery 50 or an output side device (not shown) having a female positive socket and a female negative socket fitted to the male positive socket 18a and male negative socket 18b provided in the connector main body 18; Connection is possible.

For this reason, it is possible to easily attach and remove the remaining capacity measuring device 10 of the present invention, the battery 50, and the output side device (not shown). Reference numeral 18c denotes a lock mechanism for preventing the plug-in connector 16 from coming off due to vibration or the like when connected to the battery 50 and an output device (not shown).

Such a plug-in connector 16 is used to easily attach and remove the remaining capacity measuring device 10 of the present invention between the battery 50 to be measured and an output device (not shown). The remaining capacity measuring device 10 of the present invention may be attached between the battery 50 and an output side device (not shown) without using the plug-in connector 16. .

As described above, in the remaining capacity measuring device 10 of the present invention attached between the battery 50 and the output device (not shown), the measuring means 20 detects the battery current when the battery 50 is charged and discharged. The detected battery current value is input to the storage means 24 as one of the remaining capacity related data, and is sequentially stored.

Further, the battery current value stored in the storage means 24 as the remaining capacity related data is stored as data related to the time, and based on the battery current value and the time, the charge amount when the battery 50 is charged or The amount of discharge during discharge can be calculated by the calculation means 30.

As the remaining capacity related data, not only the battery current amount but also the battery voltage value at the time of charging / discharging of the battery 50, the calculated remaining capacity of the battery 50, and the like can be stored.

In particular, by storing the battery voltage value at the time of charging / discharging of the battery 50 as data associated with the time, the battery 50 can be more accurately charged based on the battery current value, the battery voltage value, and the time. The amount of charge and the amount of discharge at the time of discharging can be calculated by the computing means 30.

In the present invention, as the storage means 24, known storage means such as RAM (Random Access Memory), flash memory (nonvolatile semiconductor memory), and hard disk drive can be used.

In the present invention, the calculation means 30 is, for example, a CPU (Central Processing Unit) capable of general-purpose calculation processing or an IC (Integrated Circuit) capable of only the calculation processing used in the remaining capacity measuring apparatus 10 of the present invention. For example, known calculation means can be used.

In addition, the remaining capacity measuring device 10 of the present embodiment is provided with a display 40 that constitutes display means. The display for display 40 is configured to display at least the remaining capacity of the battery 50 calculated by the calculation means 30.

The data displayed on the display 40 is not limited to the remaining capacity of the battery 50. For example, the battery voltage value or current value of the battery 50 may be displayed. Further, a thermometer may be provided in the battery 50 so that the temperature of the battery is displayed. In these cases, the data display can be switched according to the input from the data input means 38, which will be described later.

Further, in this embodiment, the display 40 is connected to the calculation means 30 and is integrally configured as the remaining capacity measuring device 10, but a wired cable (not shown) is provided by providing a communication means 36 as will be described later. And the remaining capacity measuring device 10 and the display 40 can be connected by wireless communication, so that the display 40 can be configured as a separate device from the remaining capacity measuring device 10 main body.

Further, in this embodiment, the remaining capacity measuring device 10 includes a communication unit 36, and can be connected to the display 40 as described above, or via a radio wave 36a as shown in FIG. Wireless communication with the data input means 38, the storage device 52, and the computer 54 provided outside.

As described above, by communicating with the storage device 52 or the computer 54 provided outside, the remaining capacity related data that cannot be stored in the storage unit 24 of the remaining capacity measuring device 10 is stored in the external storage device 52 or the computer 54. It is also possible to perform a precise diagnosis of the battery 50 by the computer 54 based on the stored remaining capacity related data.

The communication means 36 is not particularly limited, and may be wired communication or wireless communication.
In this embodiment, the remaining capacity measuring device 10 includes a data input unit 38. The data input means 38 is used when setting a temporary remaining capacity initial value when the remaining capacity of the battery 50 is measured for the first time, or switching data displayed on the display 40 for display.

In addition, for the battery 50 whose remaining capacity is measured (estimated) by the remaining capacity measuring apparatus 10 of the present invention, an individual identification number can be assigned to each battery in order to identify the battery.
In this way, by assigning an individual identification number to the battery, the remaining capacity related data is stored in the storage unit 24 in a state associated with the identification number. With this configuration, the remaining capacity measuring device 10 can store the remaining capacity related data of a plurality of batteries based on the identification number. The remaining capacity can be measured (estimated) in parallel.

Hereinafter, a method for measuring (estimating) the remaining capacity in the remaining capacity measuring apparatus 10 of the present invention will be described with reference to FIGS.
First, as shown in FIG. 2, with the remaining capacity measuring device 10 of the present invention connected between the battery 50 and an output device (not shown), the identification number of the battery 50 is assigned to the remaining capacity measuring device 10. Is stored in the storage means 24.

The upper limit value Zm, the alarm lower limit value Zl, the charge overvoltage value Vc, the alarm lower limit voltage value Vl, the discharge lower limit voltage value Vd, the charge efficiency coefficients Kc1, Kc2, the discharge efficiency coefficient Kd1, and the remaining capacity table ZT1 , ZT2, ZT3, ZT4, ZT5, timer duration T, interval time t, provisional remaining capacity initial value Z0, etc., based on the rated value of battery 50, data determined at the time of precise diagnosis of battery 50, etc. It memorize | stores in the memory | storage means 24 (S10). At this time, it is not necessary to store an optimum value as the temporary remaining capacity initial value Z0, and an arbitrary value may be stored.

Next, when the state of charging / discharging of the battery 50 is determined and it is determined that charging is in progress (S11), the battery voltage of the battery 50 is measured by the measuring unit 20 and stored in the storage unit 24 (S12). . If the battery voltage has not reached the charging overvoltage value Vc, Kc1 is selected as the charging efficiency coefficient (S13), and if the battery voltage has reached the charging overvoltage value Vc, Kc2 is selected as the charging efficiency coefficient. (S14).

Here, the charging efficiency coefficients Kc1 and Kc2 represent the proportion of the current flowing in the battery 50 that is actually charged. If the charging efficiency coefficients Kc1 and Kc2 are in a state before the charging overvoltage value Vc is reached, Kc1 is, for example, 0 .9 (90%) can be set, but when the charging overvoltage value Vc is reached, Kc2 is, for example, about 0.2 (20%).

When the charging efficiency coefficient Kc is set more finely, the charging efficiency coefficient Kc may be selected from three or more by setting a plurality of charging overvoltage values Vc.

When the charging efficiency coefficient Kc is set, the remaining capacity of the battery 50 is calculated as shown in Equation 1 by using the battery charging current Ac and the charging efficiency coefficient Kc measured by the measuring means 20 and stored in the storage means 24. To do.

Next, it is determined whether or not the state of charging continues (S16). If charging continues, the process returns to S12, and the remaining capacity at the time of charging is calculated again. An end process is performed (S17).

In the charge termination process, if the remaining capacity of the battery 50 after the completion of charging exceeds the upper limit value Zm of the remaining capacity stored in the storage unit 24, the upper limit value of the remaining capacity stored in the storage unit 24 Update Zm. Thus, when the battery 50 is discharged, the remaining capacity of the battery 50 can be calculated by subtracting the discharge amount from the upper limit value Zm of the remaining capacity.

When it is determined that the battery 50 is in a discharged state (S19), the battery voltage of the battery 50 is measured by the measuring unit 20 and stored in the storage unit 24 (S20). When the battery voltage does not reach the discharge lower limit voltage value Vd, the discharge efficiency coefficient Kd is set (S21), and the battery discharge current Ad and the discharge efficiency coefficient Kd measured by the measuring means 20 and stored in the storage means 24 are set. By using this, the remaining capacity of the battery 50 is calculated as shown in Equation 2.

Here, the discharge efficiency coefficient Kd represents the proportion of the current actually discharged from the current flowing from the battery 50, and is set as appropriate depending on the type of the battery 50, the type of the device on the output side, and the like. Value.

Note that, similarly to the charging efficiency coefficient, it may be configured to select from a plurality of discharging efficiency coefficients according to the battery voltage.

If the remaining capacity of the battery 50 is lower than the alarm lower limit value Zl (S23) or the battery voltage of the battery 50 is lower than the alarm lower limit voltage value Vl (S24), the remaining capacity alarm is output. (S25). For the remaining capacity alarm, for example, a method such as sound, light, display on the display 40 can be used. The remaining capacity alarm is monitored by a timer (S26), and when the remaining capacity alarm output time reaches the timer duration T, the remaining capacity alarm is reset.

Next, it is determined whether or not the discharge state continues (S27). If the discharge continues, the process returns to S20, and the remaining capacity at the time of discharge is calculated again. An end process is performed (S28).

In the discharge end process, the remaining capacity of the battery 50 is corrected based on the battery voltage of the battery 50 after the end of discharge and the remaining capacity tables ZT1 to ZT5.
Specifically, based on the remaining capacity tables ZT1 to ZT5, for example, the remaining capacity correction function Zc (V) is obtained using linear interpolation or linear approximation.

Then, the remaining voltage Zt at the end of discharge is obtained by substituting the battery voltage of the battery 50 at the end of discharge into the remaining capacity correction function Zc (V). Then, this remaining capacity Zt is stored in the storage means 24 as the current remaining capacity of the battery 50.

The remaining capacity tables ZT1 to ZT5 indicate the relationship between the battery voltage and the remaining capacity when the battery 50 is in use (load state). For example, the remaining capacity tables ZT1 to ZT5 are theoretically based on the rated capacity, rated voltage, etc. of the battery 50. It can also be obtained by performing a close inspection of the battery 50. Further, the number of remaining capacity tables is not particularly limited, and it is sufficient that a number sufficient to create the remaining capacity correction function Zc (V) is stored.

In S20, when the battery voltage of the battery 50 reaches the discharge lower limit voltage value Vd, a polarity inversion alarm is output (S29), assuming that the cell of the battery 50 is in polarity.

In the present embodiment, only an alarm is output, but a calculation process may be performed on the cell reversal of the battery 50.
If it is determined that the battery 50 is in a resting state (S30), the natural discharge current Ak flowing from the battery is measured by the measuring means 20, and the remaining capacity of the battery 50 is calculated as shown in Equation 3 (S31). ).

Next, it is determined whether or not the hibernation state continues (S32). If the hibernation state continues, the process returns to S31, the remaining capacity in the hibernation state is calculated again, and if the hibernation state has ended, The discharge end process of S28 is performed.

After the charge end process is performed in S17 and the discharge end process is performed in S28, it is determined whether or not a remaining capacity measurement end command is input (S18). If no end command is input, the process returns to S11. Then, the remaining capacity measurement described above is repeated.

Thus, by measuring (estimating) the remaining capacity of the battery 50 that repeats charging and discharging while correcting the remaining capacity at the end of discharging and updating the upper limit value Zm of the remaining capacity at the end of charging, It is possible to perform a remaining capacity measurement that eliminates the need for temperature correction during use.

In the above-described embodiment, an alarm is output when the remaining capacity of the battery 50 falls below the alarm lower limit value Zl or when the battery voltage of the battery 50 falls below the alarm lower limit voltage value Vl. Not limited to this, for example, when the temperature of the battery rises abnormally, or as shown in FIG. 7, for example, when a battery with a rated 300 AH is repeatedly charged, only about 10 AH to 30 AH is charged. The alarm may be output even in a state in which the battery voltage value is suddenly decreased during the discharge of the battery as shown in FIG.

As described above, when an abnormality occurs in the charge amount or battery voltage value of the battery 50 during charging / discharging of the battery 50, it is considered that the cell balance of the battery 50 is lost. If it is used, it will be difficult to accurately measure (estimate) the remaining capacity. For example, if it is used for a forklift or an electric vehicle, it will suddenly stop moving. .

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to this. For example, the battery 50 is periodically inspected to check the remaining capacity tables ZT1 to ZT5 and the charge overvoltage value. Various changes can be made without departing from the object of the present invention, such as appropriately updating an initial value such as Vc.

DESCRIPTION OF SYMBOLS 10 Remaining capacity measuring apparatus 12a Battery side positive terminal 12b Battery side negative terminal 14a Output side positive terminal 14b Output side negative terminal 16 Plug-in type connector 20 Measuring means 22 Shunt resistance 24 Storage means 30 Calculation means 36 Communication means 36a Radio wave 38 Data input Means 40 Display for display 50 Battery 52 Storage device 54 Computer

Claims (10)

A remaining capacity measuring device for measuring the remaining capacity of a battery,
A measuring means for measuring remaining capacity related data;
A storage unit storing a preset remaining capacity table and a preset upper limit value of the remaining capacity of the battery, and storing remaining capacity related data measured by the measuring unit;
An arithmetic device that calculates the remaining capacity of the battery based on the remaining capacity related data stored in the storage means,
The storage means sequentially stores the measured remaining capacity related data of the battery during charging and discharging, and calculates the remaining capacity of the battery based on the remaining capacity related data of the battery stored in the storing means.
At the end of charging of the battery, if the remaining capacity of the battery exceeds the upper limit value of the remaining capacity, the upper limit value of the remaining capacity is updated with the remaining capacity of the battery,
A remaining capacity measuring apparatus that corrects the remaining capacity of the battery based on the remaining capacity table when the battery is discharged. When charging the battery, the voltage value of the battery is measured by the measuring means, and a predetermined charging efficiency coefficient is selected based on the voltage value of the battery,
The remaining capacity of the battery is calculated by the computing means based on the measured battery charging current flowing in the battery and the predetermined charging efficiency coefficient stored in the storage means. The remaining capacity measuring device according to claim 1. When the battery is discharged,
The remaining capacity of the battery is calculated by the calculation means based on a measured battery discharge current discharged from the battery and a predetermined discharge efficiency coefficient stored in the storage means. The remaining capacity measuring device according to claim 1 or 2. 4. The remaining capacity measuring device according to claim 3, wherein a voltage value of the battery is measured by the measuring means, and a predetermined discharge efficiency coefficient is selected based on the voltage value of the battery. . 5. The remaining capacity measuring device according to claim 1, wherein the remaining capacity measuring device comprises display means for displaying at least the remaining capacity of the battery. The said remaining capacity measuring device is provided with the communication means for communicating with at least any one among the said display means, the memory | storage means provided outside, and the computer provided outside. The remaining capacity measuring device according to any one of 5. Each battery has an individual identification number for each battery,
The remaining capacity measuring device according to any one of claims 1 to 6, wherein the storage means stores remaining capacity related data associated with a battery identification number. In the remaining capacity measuring device,
A battery-side terminal for connection to the battery terminal;
An output side terminal constituting the output side terminal, and
8. The remaining capacity measuring device according to claim 1, wherein each of the battery side terminal and the output side terminal is a plug-in connector. The remaining capacity measurement according to any one of claims 1 to 8, wherein an alarm is output when the arithmetic unit detects an abnormality of the battery during charging and discharging of the battery. apparatus. 10. The remaining capacity measuring device according to claim 9, wherein an alarm is output when the remaining capacity of the battery falls below a predetermined alarm lower limit during charging and discharging of the battery.

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