JP3500950B2 - Battery pack - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention calculates the state of a battery during operation, such as a remaining capacity that can be discharged, and manages the power of an apparatus body to which the battery is mounted. For this purpose, a battery management unit (Battery Management Un) that outputs data indicating the state of the battery to the device body
and a battery pack for supplying power to a load composed of a power tool such as a notebook computer or an electric screwdriver. 2. Description of the Related Art In recent years, battery packs having a BMU function of calculating and outputting the number of repetitions of charge / discharge and the remaining capacity have been widely used. The operation of this battery pack will be described below with reference to FIG. FIG. 2 is a block diagram showing a conventional battery pack 1 having a function of counting the number of charge / discharge repetitions and a device main body 2. [0005] The battery pack 1 and the main body 2 of the battery pack 1 have the + terminal of the battery pack 1 and the + terminal of the main body 2, and the − terminal of the battery pack 1 and the − terminal of the main body 2 have the same connection. Are electrically connected to a data communication terminal a of the device main body 2 by a connector or the like. The current supplied from the battery pack to the equipment body flows from the + terminal of the battery block 3 in which a plurality of secondary batteries are connected in series, to the load 4 of the equipment body 2, and passes through the current detection resistor 5 to the battery. Return to the negative terminal of block 3. The charge / discharge current flowing through the battery block 3 is 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 + or-. If the charge state is a discharge state, the discharge current integration circuit 9 performs a discharge current integration calculation process.
Also, when the battery switches from discharging to charging, the integrated discharge current is cleared to zero. The discharge capacity setting circuit 11 stores a preset discharge capacity. 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 are the discharge capacity. The comparison is performed by the comparison circuit 12b. 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. [0007] The signal of the number of charge / discharge repetitions is output to the display unit 14, converted into communication data by the communication circuit unit 15, and passed through the data communication terminal a of the battery pack 1 and the data communication terminal b of the device body 2. The data is input to the device main body circuit 16 and arithmetic processing is performed as data of the battery pack 1 from the BMU. However, in the battery pack having the function of counting the number of times of repetition of charge / discharge, if the cumulative discharge capacity value becomes equal to or more than the set discharge capacity value, the number of charge / discharge repetitions is reduced. The normal operation counts up by one, but charging is performed during discharge or when discharge stops.
When the electricity is charged, the accumulated discharge capacity value is reset,
If charge / discharge is repeated in a state where the accumulated discharge capacity value is less than the set discharge capacity value, the number of charge / discharge repetitions is not counted up even though charge / discharge is 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 has a function of counting the number of times of repetition of charging and discharging so that the correlation between the actual use state of the battery pack and the number of times of recharging can be properly obtained. It is intended to provide a battery pack. [0010] In order to achieve the above object, the present invention provides a battery pack comprising a secondary battery and a measuring unit for measuring the number of charge / discharge repetitions of the battery. The measuring unit detects whether the secondary battery is in a charged state or a discharged state.
Only when the secondary battery is detected to be in a discharged state, the discharged capacity of the secondary battery is accumulated, and when the accumulated discharge capacity reaches the set discharge capacity, the number of charge / discharge repetitions is set to 1
Times and reset the accumulated discharge capacity .
It was assumed having a that function. DETAILED DESCRIPTION OF THE INVENTION The present invention is a battery pack having the above-described contents, and in particular, accumulates the discharged capacity of a secondary battery only when the secondary battery is in a discharged state. When the capacity reaches the set discharge capacity, the number of charge / discharge repetitions is counted as one, and the accumulated discharge capacity is reset.
It has a function to cut. With such a configuration, even when the battery capacity is not fully used and the shallow discharge and charge are used repeatedly, the number of charge / discharge repetitions is grasped and the battery is deteriorated due to charge / discharge. The degree can be quantified correctly. In other words, this battery pack can quantitatively determine the degree of aging, thereby greatly improving the maintainability of the battery pack and accurately controlling the device main body and the battery pack. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a battery pack 1 and a device main body 2 according to an embodiment of the present invention. The battery pack 1 and the main body 2 of the battery pack 1 have the + terminal of the battery pack 1 and the + terminal of the main body 2, and the − terminal of the battery pack 1 and the − terminal of the main body 2 have the same connection. Are electrically connected to a data communication terminal a of the device main body 2 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 direction of current during charging and discharging of the battery block 3 in which five nickel-hydrogen storage batteries are connected in series is detected as a potential difference between both ends of the current detection resistor 5. Reference numeral 6 denotes a measurement unit, 7 denotes 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, 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. 1
Reference numeral 6 denotes a device main body circuit provided in the device main body 2. Next, the operation of the battery pack according to the embodiment of the present invention will be described in detail. Potential difference between both ends of the current detection resistor 5 (data of current direction during charging and discharging)
Are converted into digital data by the AD conversion circuit 7. If the digital data is positive, the charge is performed, and if the digital data is negative, the discharge is performed. The charge / discharge detection circuit 8 detects whether the digital data 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 the discharge capacity accumulating circuit 1
It is input to 0, where the accumulation operation is performed. The accumulated discharge capacity and the discharge capacity setting circuit 1
The set discharge capacity set to 1 is the discharge capacity comparison circuit 1
When the comparison is made at 2a, when the accumulated discharge capacity reaches the set discharge capacity, the charge / discharge repetition number counter 13 is counted up by one, and at the same time, the accumulated discharge capacity of the discharge capacity accumulation circuit 10 is reset to zero. The number of charge / discharge repetitions obtained by the charge / discharge repetition 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 is used for arithmetic processing and the like as data on the number of charge / discharge repetitions of the battery pack 1 from the BMU. After resetting the cumulative discharge capacity to 0, the discharge capacity accumulating circuit 10 restarts the accumulating operation in response to an input signal from the discharging current integrating circuit 9, and the above-described counting operation is repeated. As described above, in the battery pack of the present invention, in addition to counting up the charge / discharge repetition number counter by one when the battery is discharged to the set discharge capacity after charging, Even if shallow discharge and charge are repeated without using up all the capacity, the charge / discharge repetition counter is counted up by one even when the accumulated discharge capacity integrated by the discharge capacity accumulation circuit reaches the set discharge capacity. Since the battery pack has the function, the correlation between the actual use state of the battery and the calculated number of charge / discharge repetitions can be properly obtained, and excellent maintenance of the battery pack can be performed. 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 battery pack and a device main body in an embodiment of the present invention. FIG. 2 is a block diagram showing a battery pack and a device main body in a conventional example. 2 Equipment main 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 12a Discharge capacity comparison circuit 13 Charge / discharge repetition counter 14 Display unit 15 Communication circuit unit 16 Main unit circuit

Claims (1)

(57) and [Claims 1. A secondary battery, a battery pack that includes a measuring unit for measuring the charge and discharge number of repetitions of the cell, the measurement unit, the secondary battery To determine if the
Only when the secondary battery is detected to be in a discharged state, the discharged capacity of the secondary battery is accumulated, and when the accumulated discharge capacity reaches the set discharge capacity, the charge / discharge repetition count is set to 1 A battery pack having a function of counting up and resetting the accumulated discharge capacity.