JPH1189105A - Residual charging time calculation, residual charging time display device and charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge device which can more accurately grasp residual charging time. SOLUTION: This charging device, which charges a secondary battery 1 constituted of a plurality of single-cells C1 to Cn as a constant-power and constant-current control method, is provided with a current sensor 5 which detects charging current I, a battery controller 2 which calculates a residual charging time to through an expression 'A(elapsed time after charging has started)=tc' by obtaining a required charging time A based on the charging rate of the secondary battery 1 before the start of charging during constant- power charging, and calculates the remaining charging time to through an expression '(residual correction time)-(elapsed time after residual correction time is calculated)=tc', using the remaining correction time calculated based on a charging current I detected by the current sensor 5 each time when the cell voltage of any of the single-cells C1 to Cn becomes a prescribed value or higher, at the time of switchover from constant-power charging to constant- current charging and during the constant-current charging, and an indicator 8 which displays the calculated remaining charge time tc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calculating a remaining charge time when charging a secondary battery, a remaining charge time display device, and a charging device.

[0002]

2. Description of the Related Art Conventionally, this kind of technology is disclosed in
As disclosed in Japanese Unexamined Patent Application Publication No. 298728/1990, the current and voltage of the secondary battery during charging are detected, and compared with a charging voltage characteristic curve and a charging current characteristic curve stored in a storage circuit in advance, until the charging is completed. 2. Description of the Related Art A charging device that calculates a time and displays the calculated time on a display device is known. In addition, in the case of a timer-controlled charging device in which the relationship between the charging rate (SOC: State Of Charge) of the secondary battery and the charging time is determined in advance, and the required charging time is set based on the SOC at the start of charging. On the other hand, it was possible to display the remaining charge time until the completion of charging by displaying the remaining charge time of the timer on a display.

[0003]

However, in the case of the above-mentioned Japanese Patent Application Laid-Open No. 8-298728, the characteristic curves and the required charging time in the timer control method are obtained in advance for a predetermined state (for example, an initial state) of the battery. It was done. However, the time until the charging is completed varies depending on the battery temperature, the deterioration state, the load state during the charging, and the like. Therefore, when charging is performed until the remaining charge time displayed on the display becomes zero, the charging is completed. However, there is a possibility that charging may be excessive or insufficient. Therefore, in order to avoid such an excess or deficiency of charging, charging must be stopped before the displayed remaining charge time becomes zero, or charging must be performed after the display becomes zero. However, there is a possibility that a difference may occur between the time when charging is actually completed and the displayed remaining charge time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for calculating a remaining charge time which can reduce a difference between a time when charging is actually completed and a remaining charge time obtained by calculation, and an accurate remaining charge time. An object of the present invention is to provide a remaining charge time display device and a charging device that can be understood.

[0005]

Means for Solving the Problems According to the invention of claim 1, when charging a secondary battery by a constant power and constant current control method, a required time until charging is completed based on a charging rate of the secondary battery at the start of charging. The present invention is applied to a remaining charge time calculation method in which a charge time is calculated, and a time obtained by subtracting the charge time from the required charge time is set as a remaining charge time, at the time of transition from constant power charge to constant current charge and during constant current charge. Each time the charge current value decreases, the remaining charge time is corrected based on the charge current value to calculate the corrected remaining time, and the elapsed time from when the corrected remaining time is calculated is subtracted from the corrected remaining time. Is set as the remaining charge time, thereby achieving the above object. According to a second aspect of the present invention, when the secondary battery is charged by the constant power and constant current control method, the required charging time until the completion of charging is calculated based on the charging rate of the secondary battery at the start of charging, and the required charging time is calculated. Applied to the remaining charge time display device that displays the time obtained by subtracting the charge time from the time as the remaining charge time, during the transition from constant power charging to constant current charging and during constant current charging,
Each time the charge current value decreases, the remaining charge time is corrected based on the charge current value to calculate the corrected remaining time, and the remaining charge time is calculated by subtracting the elapsed time from the correction remaining time calculation from the corrected remaining time. The above object is achieved by displaying the time. The invention of claim 3 charges a secondary battery 1 composed of a plurality of single cells C1 to Cn by a constant power and constant current control method. A charging device for determining a required charging time A based on (a) a current sensor 5 for detecting a charging current I, and (b) during constant power charging, based on a charging rate of the secondary battery 1 before starting charging; The following equation (3)

[Equation 3] (Required charging time A) − (Elapsed time from the start of charging) = (Remaining charging time tc) (3) The remaining charging time tc is calculated according to (3), and the transition from constant power charging to constant current charging is performed. And during the constant current charging, each single cell C1 ~
Each time any cell voltage of Cn becomes higher than a predetermined value (see FIG. 2).
At t2, t3, t4, t5, t6), the remaining correction time is obtained based on the charging current I detected by the current sensor 5, and the following equation (4) is obtained.

[Mathematical formula-see original document] (Remaining correction time)-(Elapsed time since calculation of the remaining correction time) = (Remaining charging time tc) ... (4)
And (c) a display 8 for displaying the remaining charge time tc calculated by the arithmetic units 2, 6, and 7 to achieve the above object.

[0006]

As described above, according to the first aspect of the present invention, each time the charging current value decreases during the transition from the constant power charging to the constant current charging and during the constant current charging, the charging is performed. The remaining charge time is corrected based on the current value to calculate the corrected remaining time, and the remaining charge time is calculated by subtracting the elapsed time from the corrected remaining time from the corrected remaining time. It is possible to calculate a more accurate remaining charge time that reflects the state and the load state during charging. According to the invention of claim 2, during the transition from constant power charging to constant current charging and during constant current charging, each time the charging current value decreases, the remaining charge time is corrected based on the charging current value. The remaining battery charge time is calculated, and the remaining charge time is subtracted from the elapsed time from the calculation of the remaining compensation time. The remaining battery charge time is displayed as the remaining charge time. A more accurate remaining charge time that reflects the state is displayed, and the charge completion time can be known more accurately. According to the invention of claim 3, during the transition from the constant power charging to the constant current charging and during the constant current charging, each time any one of the cell voltages of the single cells becomes equal to or higher than the predetermined value, the charging at that time is performed. The remaining charge time is corrected and displayed based on the current, so the more accurate remaining charge time that reflects the battery temperature, deterioration state, and load state during charging is calculated, and the charge completion time is known more accurately. be able to.

[0007] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to the embodiment.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram illustrating an embodiment of a method for calculating a remaining charge time according to the present invention, and is a block diagram illustrating a configuration of a secondary battery and a charging device used for charging the secondary battery. Reference numeral 1 denotes a secondary battery, which is composed of n single cells C1
To Cn, for example, a lithium ion battery or the like is used. Reference numeral 2 denotes a battery controller which controls charging of the secondary battery 1 by the charger 3. The battery controller 2 detects a terminal voltage Vt of the battery 1 detected by the voltage sensor 4 and a current flowing through the battery 1 detected by the current sensor 5. I, the cell voltage signal Sc from the cell controller 6 described later and the SO of the battery 1 stored in the storage device 7
The charging is controlled based on C. The cell controller 6
The charge / discharge control of each single cell C1 to Cn of the battery 1 is performed, and the cell voltage Vc of each single cell is detected. The cell voltage signal Sc for each cell voltage Vc changes from off to on when any one of the cell voltages Vc of the single cells C1 to Cn exceeds a predetermined voltage. Reference numeral 8 denotes a display provided in the charger 3, which displays the remaining charge time calculated by the battery controller 2.

As a method of calculating the SOC, for example, based on the voltage and current at the time of discharge detected by the voltage sensor 4 and the current sensor 5, the integrated value of the discharge amount from the fully charged state to the start of charging is calculated. There is a method of subtraction, etc., and the SOC is calculated by the battery controller 2 and stored in the storage device 7.

FIGS. 2A and 2B are diagrams for explaining the constant power / constant current control method and the remaining charge time of the secondary battery. FIG. 2A shows the change in the charging power P, and FIG. FIG. 9 is a diagram showing a change in the cell voltage Vc of the cell having the highest SOC, (c) shows a change in the charging current I, and (d) shows a change in the remaining charge time tc. In each drawing, the horizontal axis represents the charging time. In the constant power and constant current control method, charging with constant power (hereinafter, referred to as a CP mode) is started as shown in FIG. In this state, the cell controller 6
Is in the ON state. When charging is continued in the CP mode, the voltage Vc gradually increases, reaches a predetermined voltage Vmax at the charging time t1, and shifts the charging method to charging with a constant current (hereinafter, referred to as CC mode). In addition,
FIG. 2B shows a change in the cell voltage Vc of the single cell having the highest SOC, but shows a similar change in the other cells, and the cell voltage of any one of the cells has a predetermined value Vmax.
, The cell controller 6 outputs the cell voltage signal S
Change c from off to on.

When the cell voltage Vc becomes Vmax, the cell voltage signal Sc of the cell controller 6 changes from off to on, and the charging current I is reduced. At this time, when the charging current I decreases and the cell voltage Vc decreases, the cell voltage signal Sc returns from on to off. When the charging current I decreases, the cell voltage Vc once decreases, but gradually increases as the charging time elapses. Then, at time t2, the cell voltage Vc becomes Vma again.
When the cell voltage signal Sc changes from off to on as x, the charging current I is further reduced. Such a procedure is repeated (six times in the example shown in FIG. 2), and the charging current I
Is smaller than the charging end target current Imin (time t6), the charging ends.

Next, a method of calculating the remaining charge time will be described with reference to the flowcharts shown in FIGS. FIG. 3 is a flowchart showing a procedure for calculating the remaining charge time performed by the battery controller. The flow in FIG. 3 starts at the same time when charging of the battery 1 by the charger 3 is started. In step S1, a table T1 relating to the SOC at the start of charging and the remaining charge time stored in the storage device 7 is set.
Is calculated on the basis of the remaining charge time tc at the start of charging. The table shown in FIG. 4A shows an example of the table T1. For example, when the SOC is 40 (%), the time A = 5 (hr) in the table T1 is set as the remaining charge time tc. SO
If the value of C is not in the table T1 (for example, 45
(%), Etc., and may be obtained by linear approximation from values before and after that. In step S2, the remaining charge time A at the start of charging calculated in step S1 is transmitted to the charger 3, and the remaining charge time A is displayed on the display 8.

Step S3 is a step of judging whether or not the cell voltage signal Sc has turned on. For example, as shown in FIG. 2, the cell voltage signal Sc is changed from the CP mode to the CC mode at time t1. When turned on, step S4
Otherwise, to step S5. This step S3 is executed every 100 (msec). When the process proceeds to step S4, the remaining charge time tc is corrected to the time B in the table T2 in FIG. 4B based on the charge current value I at that time. At time t1, the charging current value I
Is 14 (A), the remaining charge time tc is corrected to time B = 60 (min) in the table T2. In step S5,
100 (msec) is subtracted from the remaining charge time tc, the result is transmitted to the charger 3 and displayed on the display 8 and the process returns to step S3. Here, the remaining charge time tc in step S5
Is time B when the process proceeds to step S4 in step S3, and time A in other cases. The tables T1 and T2 are stored in the storage device 7 in advance.

Thereafter, step S3 is performed until charging is completed.
The operation from to is performed repeatedly. As described above, since step S3 is performed every 100 (msec), one cycle from step S3 to step S5 is performed every 100 (msec), and the display is 100.
(Msec).

An example of the remaining charge time tc shown in FIG. 2D will be described. The charge remaining time at the start of charging is A, and the charge time t1 for shifting from the CP mode to the CC mode.
It decreases linearly with the passage of charging time. Time t
At 1 the cell voltage signal Sc is turned on and the current value I is 14
When it decreases to (A), the remaining charge time tc is corrected to the time B = 60 (min) in the table T2 as described above.
Thereafter, the remaining charge time tc decreases linearly and becomes tc = 50 (min) at time t2. At time t2, the cell voltage signal Sc is turned on again, and the current value at that time = 1
From 2 (A), the remaining charge time tc is the time B = 5 in the table T2.
It is corrected to 0 (min). This is the same as the value linearly reduced from the time t1, so that the remaining charge time tc is equal to the time t2.
Does not change stepwise but continues to change linearly at time t
At 3, tc = 40 (min).

Further, at time t3, the cell voltage signal Sc is turned on again. From the current value = 8 (A) at that time, the remaining charge time tc is calculated as time B = 30 (min) in the table T2.
Is corrected to Thereafter, at the times t4, t5, and t6, the remaining charge time tc is corrected based on the table T2. When the cell voltage signal Sc is turned on at time t6, the charging current value becomes smaller than the charging stop current value Imin.
At time t6, charging is stopped and charging is completed.

Changes in the charging current I and the cell voltages Vc after the transition from the CP mode to the CC mode as described above depend on the temperature, the deterioration state, and the load state during charging of each of the single cells C1 to Cn constituting the battery. Therefore, by correcting the remaining charge time based on the charging current I each time the cell voltage signal Sc is turned on, a more accurate remaining charge time can be obtained.

In the correspondence between the embodiment described above and the elements of the claims, the battery controller 2, the storage device 7, and the cell controller 6 constitute an arithmetic unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a secondary battery 1 and a charging device used for charging the secondary battery.

2A and 2B are diagrams illustrating a constant power / constant current control method and a remaining charge time of a secondary battery, wherein FIG. 2A illustrates a change in charging power P, FIG. 2B illustrates a change in cell voltage Vc, and FIG. Indicates a change in the charging current I, and (d) indicates a change in the remaining charging time tc.

FIG. 3 is a flowchart showing a procedure for calculating a remaining charge time.

4A and 4B are diagrams showing tables T1 and T2, wherein FIG. 4A is a table T1, and FIG. 4B is a table T2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Battery controller 3 Charger 4 Voltage sensor 5 Current sensor 6 Cell controller 7 Storage device 8 Display C1-Cn Single cell Sc Cell voltage signal

Claims (3)

[Claims] When charging a secondary battery by a constant power and constant current control method, a required charging time until completion of charging is calculated based on a charging rate of the secondary battery at the start of charging, and the required charging time is calculated based on the required charging time. In the remaining charge time calculation method in which the time obtained by subtracting the charge time is used as the remaining charge time, when the charge current value decreases during the transition from constant power charging to constant current charging and during constant current charging. The remaining charge time is corrected based on the current value to calculate a corrected remaining time, and the remaining charge time is obtained by subtracting the elapsed time from the corrected remaining time calculation from the corrected remaining time. Charge remaining time calculation method. 2. When charging a secondary battery by a constant power and constant current control method, a required charging time until completion of charging is calculated based on a charging rate of the secondary battery at the start of charging, and the required charging time is calculated from the required charging time. In the remaining charge time display device, which displays the time obtained by subtracting the charge time as the remaining charge time, during the transition from the constant power charge to the constant current charge and during the constant current charge, the charge current value decreases every time the charge current value decreases. The correction remaining time is calculated by correcting the remaining charging time based on the charging current value, and a value obtained by subtracting the elapsed time from the correction remaining time calculation from the corrected remaining time is displayed as the remaining charging time. Charge remaining time display device characterized by the above-mentioned. 3. A charging device for charging a secondary battery composed of a plurality of single cells by a constant power and constant current control method, comprising: (a) a current sensor for detecting a charging current; and (b) constant power charging. During the charging, the required charging time is determined based on the charging rate of the secondary battery before the start of charging, and the following formula (1) is obtained. (Required charging time) − (time elapsed from the start of charging) = (remaining charge) Time) ... (1) to calculate the remaining charge time, and during the transition from the constant power charging to the constant current charging and during the constant current charging, each time any one of the cell voltages of the single cells becomes equal to or higher than a predetermined value. The remaining correction time is determined based on the charging current detected by the current sensor, and the following equation (2) is obtained. (Remaining correction time) − (Elapsed time from calculation of the remaining correction time) = (Remaining charging time) An arithmetic unit for calculating the remaining charge time according to (2); and (c) the arithmetic unit A display for displaying the remaining charge time calculated Ri, charging apparatus comprising: a.