JP4460063B2 - Battery charge state detection method and charge state detection device - Google Patents

Description

The present invention relates to a charging state detection method and a charging state detection device for detecting a charging state of a battery mounted on a vehicle, and in particular, avoids the influence of pulse discharge performed at the time of measuring the impedance of the battery and accurately controls the charging amount. The present invention relates to a technical state of a charge state detection method and a charge state detection device that can be detected.

Recently, the electric load on vehicles has been increasing, and while the number of electronic control units for electronic control of main and auxiliary equipment and security devices that are operating during parking has increased, Many electrical components such as changing to an electronic display system have been installed.

In addition, in order to improve fuel efficiency and driving performance, vehicle control and power that have been conventionally performed by hydraulic pressure tend to be motorized. For example, electric power steering and electric brakes have been put into practical use. .

As described above, as the electric load of the vehicle increases, the importance of the battery supplying electric power to these electric loads is increasing. For this reason, development of various detection devices for early detection of deterioration and insufficient charging of the battery is in progress.

For example, immediately after turning on the ignition key of the vehicle, the open-circuit voltage of the battery is measured in order to detect the state of charge of the battery mounted on the vehicle. This utilizes the characteristic that when the battery is in a stable state, the open-circuit voltage of the battery is approximately proportional to the amount of charge.

Further, for the purpose of detecting the deterioration state of the battery, after measuring the open circuit voltage, a predetermined pulse discharge is performed, and the voltage and current at that time are measured. An impedance of the battery is obtained from the measured voltage and current, and the deterioration state of the battery is determined based on the impedance.

Such detection of the state of charge or deterioration of the battery is performed each time the ignition key of the vehicle is turned on. When the period from when the ignition key is turned off to when the battery is turned on becomes longer, the charge amount of the battery decreases due to natural discharge or dark current during that period. The longer the period, the lower the charge amount and the lower the open-circuit voltage.

Therefore, if the amount of charge decreases after leaving the vehicle for a long period of time, it will be detected that the open circuit voltage has decreased when the amount of charge is detected by turning on the ignition key next time. An alarm is output to inform the driver that charging is insufficient.

By the way, charging / discharging of the battery of the vehicle is repeatedly performed while the engine is running, and the open circuit voltage of the battery may rise or fall transiently due to the influence. Such transient fluctuations in the open-circuit voltage recover to a sufficiently stable state after about one day has passed since the ignition key was turned off.

However, if the ignition key is turned on before the open-circuit voltage is sufficiently stabilized, if the open-circuit voltage temporarily rises, the amount of charge detected immediately after the ignition key is turned on is detected. In this case, there is a risk of measuring a high open-circuit voltage. For this reason, there is a risk of erroneously determining that the charge amount is sufficiently secured due to the temporary increase in the open-circuit voltage, even though the charge amount is insufficient.

In order to solve such a problem, the corrected charge amount obtained by adding and adding the charge / discharge current with time to the charge amount obtained from the open-circuit voltage at the previous measurement is stored as necessary. Compared with the charge amount obtained from the open-circuit voltage measured immediately after turning on the ignition key this time, a method of detecting the state of charge using the lower charge amount is used.

However, the above method has the following problems. That is, immediately after the ignition key is turned on, the charge amount is detected, and subsequently, the deterioration state of the battery is detected. In the detection of the deterioration state, the battery is pulse-discharged, and the voltage of the battery temporarily decreases after the pulse discharge.

If the ignition key is turned off while the battery voltage is low, and then the ignition key is turned on again within a short period of time, a low open-circuit voltage is measured under the influence of the pulse discharge. There was a fear. As described above, if the ignition key is repeatedly turned on / off within a short time, the open-circuit voltage is further lowered, and it may be erroneously determined that charging is insufficient.

FIG. 2 shows an example of battery voltage change when the ignition key is repeatedly turned on and off in a short time. In the figure, the ignition key is turned on at the time of 11 for the battery whose voltage is sufficiently stable at the beginning.

When the ignition key is turned on, the open-circuit voltage of the battery is measured at 12 time points immediately thereafter, and further, pulse discharge for detecting the deterioration state of the battery is performed at 13 time points thereafter. Although the voltage temporarily decreases due to the pulse discharge, it gradually increases toward the original voltage after the voltage is recovered.

If the ignition key is turned off at 14 time points before the voltage decreased due to the pulse discharge is fully recovered, and then the ignition key is turned on again at 15 time points, then at the 16 time points immediately after that. The open-circuit voltage measured is affected by the pulse discharge performed at the time point 13 and becomes lower than the open-circuit voltage measured at the time point 12. As described above, when the ignition key is repeatedly turned on and off in a short time, the measured open-circuit voltage may gradually decrease.

Compared to the previous charge amount, the charge amount obtained from the open-circuit voltage measured immediately after turning on the ignition key this time, the conventional method that uses the lower charge amount to detect the charge amount has the effect of the above pulse discharge. If a low open-circuit voltage is temporarily measured in response to this, the amount of charge obtained from this low open-circuit voltage is stored. As a result, in the subsequent detection of the charge amount, there is a problem that the charge amount is determined based on the charge amount obtained from the stored low open-circuit voltage.

Furthermore, if the ignition key is repeatedly turned on and off in a short time, as described above, the measured open-circuit voltage gradually decreases, and as a result, it may be erroneously determined that charging is insufficient and an alarm may be output. was there.

Therefore, the present invention has been made to solve these problems, and by making it possible to avoid the influence of a temporary voltage drop due to the pulse discharge, a charged state in which the charged state of the battery can be accurately detected. An object is to provide a detection method and a state-of-charge detection device.

A first aspect of the battery state of charge detection method according to the present invention is a method for detecting the state of charge of a battery mounted on a vehicle, wherein the battery is in an activated state immediately before the engine is activated. The open-circuit voltage of the battery is measured, and the other open-circuit voltage stored in a predetermined storage means is compared with the measured open-circuit voltage, and the lower one is used as the charge amount determination voltage. In place of the voltage, the charge amount determination voltage is stored in the predetermined storage means, and after the measurement of the open circuit voltage, a predetermined pulse discharge is performed, and the impedance of the battery is determined from the voltage and current values measured at that time. determined, detects the deterioration state of the battery based on the impedance, then charges the predetermined volume with the charging device driving means to said battery, predetermined the charge amount determining voltage Converting the charge amount by the conversion means, a charging state detecting method and detecting the insufficient charging of the battery by comparing the charge level to a predetermined lower limit value.

A second aspect is a charging state detection method characterized in that the charging of the predetermined capacity is charging of a capacity necessary for a voltage immediately after charging to exceed at least the open-circuit voltage measured immediately before. .

In a third aspect, the charging of the predetermined capacity is charging of a capacity necessary for the voltage immediately after charging to exceed a voltage obtained by adding a predetermined voltage measurement resolution to at least the open-circuit voltage measured immediately before the charging. It is the charge condition detection method characterized by these.

A fourth aspect is a state of charge detection method characterized in that the charge of the predetermined capacity is charge of a capacity at least equal to or greater than a discharge amount by the pulse discharge.

According to a fifth aspect of the present invention, there is provided a method for detecting a state of charge, wherein the charging of the predetermined capacity is performed immediately after turning off the ignition key of the vehicle.

A sixth aspect is a state of charge detection method characterized in that the voltage stored in the predetermined storage means is the measured open-circuit voltage.

In a seventh aspect, the state of charge detection is characterized in that the predetermined storage means stores the charge amount determination voltage or the charge amount obtained by converting the measured open-end voltage by the predetermined conversion means. Is the method.

An eighth aspect is an apparatus for charging state detection of a battery mounted on a vehicle, the open circuit voltage measuring means for measuring the open circuit voltage of the battery-immediately after turning on the Lee Gunisshon key, the and memorize means Ru to store the said measured open circuit voltage at the open circuit voltage measuring means, a charging device driving means for driving the charging device of the vehicle so as to perform charging of Jo Tokoro volume to the battery, Starring a calculation processing unit, the arithmetic processing result of the calculation by the means and output means deterioration of the battery to output an alarm when it is detected, the charging state detection device characterized by consisting of.

According to the present invention, the state of charge can be accurately detected even when the ignition key is turned on while the voltage of the battery mounted on the vehicle is not sufficiently stable.

In particular, even when the ignition key is repeatedly turned on / off in a short time, it is possible to accurately determine the state of charge of the battery while avoiding the effect of pulse discharge performed for detecting the deterioration state of the battery. A battery charge state detection method and a battery charge state detection device can be provided.

Embodiments of a battery state-of-charge detection method and a state-of-charge detection device of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

When the ignition key is turned on, the battery mounted on the vehicle is subjected to pulse discharge for detection of a deteriorated state, which temporarily decreases the voltage of the battery. Therefore, in the battery charge state detection method of the present invention, a predetermined capacity is charged after the pulse discharge.

When the battery state of charge detection method of the present invention is used, the voltage of the battery changes as shown in FIG. 3, for example. In the figure, when the ignition key is turned on at time 21, the open-circuit voltage of the battery is measured at 22 to detect the state of charge.

Thereafter, at 23, pulse discharge is performed to detect the deterioration state of the battery. After the pulse discharge is performed, the voltage gradually recovers, but cannot immediately return to the voltage before the pulse discharge.

In the battery state of charge detection method of the present invention, the battery is charged with the predetermined capacity at a time point 24 when the voltage after the pulse discharge is in the process of recovery. Thereby, the voltage after the charging temporarily becomes higher than the voltage before the pulse discharge, but then gradually decreases and approaches the voltage before the pulse discharge.

As described above, in the method for detecting the state of charge of the battery according to the present invention, the ignition key is turned off by charging the predetermined capacity at time 24 in FIG. 3, and the ignition key is again turned on within a short time. Even when is turned on, the voltage is never lower than the voltage when the voltage is stable, so that it is not erroneously determined that charging is insufficient.

FIG. 1 is a flowchart of a process for explaining an embodiment according to a method for detecting a charged state of a battery according to the present invention. When the ignition key is turned on in step S1, the open circuit voltage of the battery is first measured (step S2). Thereafter, another open-circuit voltage stored in a predetermined storage means is read (step S3) and compared with the open-circuit voltage measured this time (step S4).

As a result of the comparison in step S4, when the open-circuit voltage measured in step S2 is lower than the other open-circuit voltage read in step S3, the open-circuit voltage is used as a charge amount determination voltage. Is set (step S5). When the open circuit voltage is higher than or equal to the other open circuit voltage, the other open circuit voltage is set as the charge amount determination voltage (step S6).

When the charge amount determination voltage is set in step S5 or step 6, the charge amount determination voltage is converted into a charge amount of the battery by a predetermined conversion means (step S7). It is known that the amount of charge of the battery is substantially proportional to the open-circuit voltage, and the predetermined conversion means can be realized using this characteristic.

An example showing the relationship between the charge amount of the battery and the open-circuit voltage is shown in FIG. Since the charge amount of the battery and the open-end voltage have a linear relationship like a straight line 31, the straight line 31 can be used in a conversion formula for calculating the charge amount from the open-end voltage. The open circuit voltage shown in FIG. 4 is a measured value when the battery is sufficiently stable.

In step S8, the charge amount obtained from the conversion formula is compared with a predetermined lower limit value. As a result, when the amount of charge is equal to or less than the predetermined lower limit value, it is determined that the battery is insufficiently charged and an alarm is output (step S9).

On the other hand, when the charge amount is larger than the predetermined lower limit value, the following processing is performed in preparation for the next charge state detection. First, in step S10, the charge amount determination voltage set in step S5 or step 6 is stored in the predetermined storage means, and the stored content is updated. And after the pulse discharge performed for detection of a deterioration state is complete | finished, only the predetermined capacity | capacitance is charged with respect to the said battery in step S11.

The charging of the predetermined capacity performed in step S11 is preferably charging with a capacity such that the voltage after charging exceeds at least the open-circuit voltage measured in step S2.

Furthermore, it is desirable that the charging of the predetermined capacity is a charging of a capacity such that the voltage immediately after the charging becomes at least a voltage obtained by adding a predetermined voltage measurement resolution to the open end voltage measured in step S2.

Alternatively, the charging of the predetermined capacity may be charging of a capacity that is at least equal to the amount of discharge discharged by the pulse discharge.

The processing from step S1 to step S11 described above is executed every time the ignition key is turned on. Therefore, even when the ignition key is repeatedly turned on / off within a short time, there is no possibility that the open-circuit voltage gradually decreases due to charging in step S11.

In the process flow of FIG. 1, when the state of charge of the battery has not decreased, the previous charge amount determination voltage stored in the storage means in the comparison in step S4 is selected. As a result, in the determination in step S8, the same determination result as the detection result of the previous charge state is obtained. That is, unless it is determined that the amount of charge is insufficient in the previous state of charge detection, the alarm in step S9 is not output.

On the other hand, when the state of charge of the battery is lowered, the open-circuit voltage measured this time in the comparison in step S4 is selected. If it is determined in step S7 that the amount of charge obtained from the open-circuit voltage measured this time is equal to or less than a predetermined lower limit in the determination in step S8, an alarm output is performed in step S9.

Next, another embodiment of the present invention will be described below.
In the above embodiment, the charge amount determination voltage is stored in the predetermined storage unit in step S10. On the other hand, in another embodiment of the present invention, in step S10, the open-circuit voltage measured in step S2 is stored in the predetermined storage means.

Since the open-circuit voltage is stored in the predetermined storage means, even if the open-circuit voltage is affected by a temporary voltage drop, the influence of the next charge amount is limited. Until the time of detection, there is no possibility that the open end voltage is continuously stored in the predetermined storage means.

Therefore, even if a warning is issued due to a misjudgment due to a temporary voltage drop, the warning will not continue three times or more.

Still another embodiment of the battery charge state detection method of the present invention will be described below.
In order to avoid the influence of the voltage drop due to the pulse discharge for detecting the deterioration state, in FIG. 1, a predetermined capacity is charged after the pulse discharge is completed in step S11.

On the other hand, in the present embodiment, instead of the charging of the predetermined capacity performed in step S11, the charging of the predetermined capacity is performed immediately after the ignition key of the vehicle is turned off.

The battery is repeatedly charged and discharged while the vehicle is running. For this reason, immediately after the ignition key is turned off, the battery voltage may be temporarily reduced due to the influence of the charge / discharge. Therefore, in the present embodiment, the predetermined capacity is charged immediately after the ignition key is turned off.

As described above, if charging is performed immediately after the ignition key is turned off, if the state of charge of the battery has not decreased, the next time the ignition key is turned on, In step S4, the previous open-circuit voltage stored in the storage unit can be selected. As a result, the alarm output in step S9 is not selected as described above.

An embodiment of the battery state of charge detection device of the present invention will be described with reference to the block diagram shown in FIG. In the figure, the battery charge state detection device 41 of the present embodiment is composed of an open-end voltage measurement means 42, an arithmetic processing means 43, a storage means 44, a charging device drive means 45, and an output means 46. In the arithmetic processing means 43, the battery charge state detection method according to any one of the above embodiments is executed.

For example, when the embodiment shown in FIG. 1 is executed by the arithmetic processing unit 43, the open end voltage measurement unit 42 is used to measure the open end voltage of the battery 51 in the measurement of the open end voltage in step S2.

In step S3, the other open-circuit voltage is read from the storage unit 44, and in step S10, the charge amount determination voltage is stored in the storage unit 44.

Furthermore, if it is determined in step S8 that the charge amount of the battery 51 is equal to or less than the predetermined lower limit value, an alarm in step S9 is output to the output means 46. On the other hand, when it is determined that the charge amount of the battery 51 is greater than the predetermined lower limit value, the charging in the step S11 is performed using the charging device driving means 45.

By configuring the battery state-of-charge detection device of the present invention as described above, the function of any form of the battery state-of-charge detection method of the present invention can be realized.

FIG. 1 is a flowchart of a process for explaining an embodiment according to a method for detecting a charged state of a battery according to the present invention. FIG. 2 is a diagram illustrating an example of a change in battery voltage when the ignition key is repeatedly turned on and off in a short time. FIG. 3 is a diagram showing an example of battery voltage change when the battery charge state detection method of the present invention is used. FIG. 4 is a diagram illustrating an example of the relationship between the charge amount of the battery and the open-circuit voltage. FIG. 5 is a block diagram for explaining an embodiment of the battery charge state detection device of the present invention.

Explanation of symbols

11, 15, 21, when the ignition key is turned on 12, 16, 22, when the open circuit voltage is measured 13, 23, when pulse discharge is performed 14, ignition The time point 24 when the key is turned off ... The time point 31 when charging is performed ... The straight line 41 representing the relationship between the open-ended voltage and the charged amount ... The charging state detection device 42 ... The open-ended voltage measuring means 43 ... arithmetic processing means 44 ... storage means 45 ... charging device driving means 46 ... output means 51 ... battery 52 ... charging device

Claims (8)

A method for detecting the state of charge of a battery mounted on a vehicle,
Measure the open circuit voltage of the battery immediately after the battery is activated before the engine is activated,
Comparing another open end voltage stored in a predetermined storage means with the measured open end voltage, the lower one is used as a charge amount determination voltage,
In place of the other open-ended voltage, the charge amount determination voltage is stored in the predetermined storage means,
After the measurement of the open circuit voltage, a predetermined pulse discharge is performed, the impedance of the battery is obtained from the voltage and current value measured at that time, and the deterioration state of the battery is detected based on the impedance,
Thereafter, the battery is charged with a predetermined capacity using a charging device driving means ,
The charge amount determination voltage is converted into a charge amount by a predetermined conversion means,
A method for detecting a state of charge, comprising: detecting an insufficient charge of the battery by comparing the charge amount with a predetermined lower limit value. The charge of the predetermined capacity is
The charge state detection method according to claim 1, wherein the voltage immediately after charging is at least a capacity necessary to exceed the open-circuit voltage measured immediately before. The charge of the predetermined capacity is
3. The charge according to claim 1, wherein the voltage immediately after charging is a charge of a capacity necessary to exceed at least a voltage obtained by adding a predetermined voltage measurement resolution to the open-circuit voltage measured immediately before. Charge state detection method. The charge state detection method according to any one of claims 1 to 3, wherein the charge of the predetermined capacity is charge of a capacity at least equal to or greater than a discharge amount by the pulse discharge. The charge of the predetermined capacity is
The charging state detection method according to any one of claims 1 to 4, wherein the charging state detection method is performed immediately after the ignition key of the vehicle is turned off. The voltage to be stored in the predetermined storage means is
The charge state detection method according to any one of claims 1 to 5, wherein the measured open-end voltage is used. In the predetermined storage means,
The charge state according to any one of claims 1 to 6, wherein a charge amount obtained by converting the charge amount determination voltage or the measured open-end voltage by the predetermined conversion means is stored. Detection method. A device for detecting the state of charge of a battery mounted on a vehicle,
And an open circuit voltage measuring means for measuring the open circuit voltage of the battery-immediately after the Lee Gunisshon key on,
And memorize means Ru to store the said measured open circuit voltage in the open circuit voltage measuring means,
A charging device driving means for driving the charging device of the vehicle so as to perform charging of Jo Tokoro volume to the battery,
And arithmetic processing means,
An output means for outputting an alarm when deterioration of the battery is detected as a result of calculation by the calculation processing means ;
A charging state detection device comprising:

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