JPH11233153A - Method for counting number of repeated charging and discharging of battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely perform the maintenance of a secondary battery by cumulating the discharged capacity of the battery, and incrementing the number of repeated charging and discharging by one while setting a cumulative discharge capacity at zero when this cumulated discharge capacity has attained a set discharge capacity. SOLUTION: A potential difference between both ends of a current detection resistance 5 is converted into digital data by an A/D conversion circuit 7, and a charge/ discharge detection circuit 8 detects whether charging or discharging takes place. During discharging, operations for integrating currents are performed by a discharge current integrating circuit 9. The cumulating discharge capacity computed is input to a discharge capacity cumulating circuit 10, where cumulating operations are performed. The cumulative discharge capacity and the discharge capacity set by a discharge capacity setting circuit 11 are subjected to cumulating operations by a discharge capacity ratio cumulating circuit 10. The cumulative discharge capacity and the set discharge capacity are compared by a discharge capacity comparison circuit 12a, and when the cumulative discharge capacity attains the set discharge capacity, the cumulative discharge capacity is reset to zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention calculates the state of a battery during operation, such as the remaining capacity that can be discharged, and manages the state of the battery in the apparatus main body in order to manage the power of the device main body to which the battery is mounted. Battery Management Unit that outputs the indicated data
The present invention relates to a method for calculating the number of times of repetition of charging / discharging of a battery having a power supply, such as a notebook personal computer or an electric screwdriver, for supplying power to a load having a power tool such as a notebook computer or an electric screwdriver.

[0002]

2. Description of the Related Art In recent years, a count calculation method of the number of times of repetition of charge / discharge has been frequently mounted on a battery pack as an important function of a BMU such as a battery pack for a notebook personal computer.

To count the number of charge / discharge repetitions,
In general, a method of detecting recovery charge after discharging at a discharge capacity equal to or greater than a predetermined discharge capacity and measuring the number of times of repetition of charge / discharge as one is generally used.

[0004] This representative method will be described below with reference to FIG.

FIG. 2 is a block diagram showing a conventional count calculation method of the number of charge / discharge repetitions.

[0006] The battery pack 1 and the device body 2 are connected to the + terminal of the battery pack 1 and the + terminal of the device body 2, the − terminal of the battery pack 1 and the − terminal of the device body 2, and the data of the battery pack 1. Communication terminal a and data communication terminal b of device body 2
Are electrically connected by a connector or the like.

[0007] The current supplied from the battery pack to the main body of the device is a battery block 3 in which a plurality of secondary batteries are connected in series.
Flows from the + terminal to the load 4 of the device main body 2 and returns to the battery block 3 through the current detection resistor 5. The charge and discharge currents flowing through the battery block 3 are represented by the potential difference between both ends of the current detection resistor 5 according to Ohm's law. The potential difference between both ends of the current detection resistor 5 is converted into a digital value by the AD conversion circuit 7. The charge / discharge detection circuit 8 detects whether the state is a charge state or a discharge state depending on whether the potential difference is positive or negative. If the state is a discharge state, the discharge current integration circuit 9 performs a discharge current integration calculation process. When the battery switches from discharge to charge, the integrated discharge current is cleared to zero. The discharge capacity setting circuit 11 stores a preset discharge capacity, and the accumulated discharge capacity calculated by the discharge current integrating circuit 9 and the set discharge capacity stored in the discharge capacity setting circuit 11 correspond to the discharge capacity. Comparison circuit 1
2b. When the accumulated discharge capacity becomes equal to or larger than the set discharge capacity, a signal is sent from the discharge capacity comparison circuit 12b to the charge / discharge repetition number counter 13, and the charge / discharge repetition number counter 13 counts up by one.

The charge / discharge repetition count is output to the display unit 14, converted into communication data by the communication circuit unit 15, and transmitted through the data communication terminal “a” of the battery pack 1 and the data communication terminal “b” of the device body 2. Input to the main body circuit 16,
Calculation processing and the like are performed as data of the battery pack 1 from the BMU.

[0009]

However, in the battery pack having the function of counting the number of repetitions of charge / discharge, if the accumulated discharge capacity value becomes equal to or greater than the set discharge capacity value, the number of charge / discharge repetitions is one. Although the normal operation of counting up is performed, if charging and discharging are repeated in a state where the accumulated discharge capacity value is less than the set discharging capacity value, the number of charge / discharge repetitions is not counted even though charging and discharging are repeated. For this reason, there was a problem that an appropriate correlation between the actual use state of the battery pack and the number of charge / discharge repetitions could not be obtained.

The present invention solves such a conventional problem, and provides a method of calculating the number of charge / discharge repetitions in which a proper correlation between the number of repetitions of charge / discharge of the battery and the aging state of the battery due to repeated use can be obtained. The purpose is to provide.

[0011]

In order to achieve the above object, a method for calculating the number of repetitions of charge / discharge of a battery according to the present invention accumulates the discharged capacity of one or a plurality of secondary batteries. When the accumulated discharge capacity reaches the set discharge capacity, the number of charge / discharge repetitions is counted up by one and the accumulated discharge capacity is reset to zero.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method for counting the number of repetitions of charge / discharge based on the above contents. In particular, the discharged capacity of a secondary battery is accumulated, and the accumulated discharge capacity is reduced to a set discharge capacity. In this case, the number of charge / discharge repetitions is incremented by one, and the accumulated discharge capacity is reset to zero.

With such a configuration, even when the battery capacity is not fully used and the shallow discharge and charge are repeatedly used, the aging degree of the battery due to charge and discharge can be correctly quantified. Therefore, by using the method of counting the number of times of charge / discharge repetition, the aging degree of the battery can be quantitatively determined. In addition, by using the data on the number of times of repetition of charge / discharge, the maintainability of the battery can be greatly improved, and the control between the device body and the power supply battery can be accurately performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a method for calculating the number of times of repetition of charging / discharging in an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a battery pack, reference numeral 2 denotes an apparatus main body, and reference numeral 3 denotes a battery block constituted by connecting five nickel-hydrogen storage batteries in series.

The battery pack 1 and the device main body 2 have the + terminal of the battery pack 1 and the + terminal of the device main body 2, and the − terminal of the battery pack 1 and the − terminal of the device main body 2 have the data of the battery pack 1. Communication terminal a and data communication terminal b of device body 2
Are electrically connected by a connector or the like. Reference numeral 4 denotes a load of the device main body 2, and reference numeral 5 denotes a current detection resistor.
The amount of current during charging and discharging of the battery block 3 is detected as a potential difference between both ends of the current detection resistor 5. 6 is a measurement unit, 7 is an AD conversion circuit connected to one end of the resistor 5,
8 is a charge / discharge detection circuit, 9 is a discharge current integration circuit, 10 is a discharge capacity integration circuit which is a feature of the present invention, 11 is a discharge capacity setting circuit, 12a is a discharge capacity comparison circuit, and 13 is a charge / discharge repetition number counter. . Reference numeral 14 denotes a display unit, and 15 denotes a communication circuit unit. Reference numeral 16 denotes a device main body circuit provided in the device main body 2.

Next, a method for counting the number of repetitions of charge / discharge in this battery pack will be described in detail.

The potential difference between both ends of the current detecting resistor 5 (current direction data at the time of charging and discharging) is calculated by an AD conversion circuit 7.
Is converted into digital data. If the digital data is +, the battery is charged, and if the digital data is-, the battery is discharged.
The charge / discharge detection circuit 8 detects whether the battery is discharged or charged. If the battery is in the discharging state, the discharging current integrating circuit 9 performs a current integrating operation. The integrated discharge capacity calculated by the discharge current integrating circuit 9 is input to the discharge capacity accumulating circuit 10, where the cumulative operation is performed.

The accumulated discharge capacity and the discharge capacity setting circuit 1
The set discharge capacity set in step 1 is the discharge capacity comparison circuit 1
When the accumulated discharge capacity is equal to the set discharge capacity, the charge / discharge repetition number counter 13 is counted up by one and the accumulated discharge capacity of the discharge capacity accumulation circuit 10 is reset to 0 at the same time.

The number of charge / discharge repetitions obtained by the charge / discharge repetition number counter 13 is output to the display unit 14 and transmitted from the communication circuit 15 through the data communication terminal a of the battery pack 1 and the data communication terminal b of the device body 2 to the device. The data is sent to the device main body circuit 16 in the main body 2 and used as arithmetic and other processing as charge / discharge repetition count data of the battery pack 1 from the BMU.

Incidentally, the count calculation of the number of charge / discharge repetitions is performed after the cumulative discharge capacity of the circuit 10 is reset to 0.
The accumulation of the discharge capacity is performed again, and the above operation is repeated.

[0023]

As described above, according to the present invention, the discharged capacity of the battery is accumulated, and when the accumulated discharge capacity is discharged to the set discharge capacity, the charge / discharge repetition counter is set to one.
This is a method of counting the number of repetitions of charging / discharging of the battery, which counts up and resets the cumulative discharge capacity to 0. Even if shallow discharge and charge are repeated without using up all the battery capacity, integration is performed by the discharge capacity accumulation circuit. When the accumulated discharge capacity reaches the set discharge capacity, the charge / discharge repetition counter has a function of counting up by one. And maintenance of the battery can be performed accurately. Further, by accurately grasping the number of repetition of charge / discharge of the battery, the data can be used to accurately control the battery pack and the device body.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a method of counting the number of repetitions of charge / discharge in an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a method of counting the number of repetitions of charge / discharge in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 battery pack 2 device body 3 battery block 4 load 5 current detection resistor 6 measuring unit 7 AD conversion circuit 8 charge / discharge detection circuit 9 discharge current integration circuit 10 discharge capacity accumulation circuit 11 discharge capacity setting circuit 12 a discharge capacity comparison circuit 13 charge / discharge Repeat counter 14 Display unit 15 Communication circuit unit 16 Main unit circuit

Claims (1)

[Claims] 1. A method of accumulating the discharged capacity of one or a plurality of secondary batteries, counting up the number of charge / discharge repetitions by one when the cumulative discharge capacity reaches a set discharge capacity, A method for counting the number of repetitions of charge / discharge of a battery for resetting the accumulated discharge capacity to zero.