JPH0462488A - Rest capacity display device for storage battery - Google Patents

Abstract

PURPOSE:To easily judge the charging period of a storage battery by calculating how many times the storage battery can be used more from its rest capacity and displaying the result. CONSTITUTION:A rest capacity arithmetic circuit 4 receives a voltage, developed when a charging current charged in the storage battery 2 with a charging operation switch SWC closed flows to a resistance R1 for charging current measurement, as data on the quantity of charging electricity through an A/D converter 5. Then a voltage developed when the discharging current from the storage battery 2 flows to a resistance R2 for discharging current measurement is received as data on the quantity of discharging electricity and those data on the quantities of charging electricity and discharging electricity are processed according to a previously stored program to detect the rest capacity of the storage battery 2. Consequently, the charging period of the storage battery can easily be judged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a remaining capacity display device that displays the remaining capacity of a storage battery in terms of the remaining number of times it can be used or the remaining usable time.

[Prior Art] Conventionally, a remaining capacity display device that detects and displays the remaining capacity of a storage battery has been provided. This is done by detecting the charging current that enters the storage battery when it is charged, and the discharge current that is discharged from the storage battery when the storage battery is connected to a load, and then adding and subtracting the time products of these charging and discharging currents to calculate the remaining amount. It calculates capacity.

The remaining capacity calculated in this way is converted to a percentage of the full charge capacity when the storage battery is fully charged, and is displayed as a percentage on the level display type display, so the user can know how much capacity will remain. You can find out what's left.

[Problems to be Solved by the Invention] However, although such conventional remaining capacity display devices can tell the current remaining capacity, they cannot display information that is effective in determining when to charge the storage battery. It was something I couldn't say. The reason for this will be explained below.

First, looking at the usage patterns of battery-powered electrical equipment that uses storage batteries, for example, in the case of power tools such as electric screwdrivers and drills, they are often used in high places such as on roofs. If the remaining capacity of the storage battery runs out during work, the worker must come down from the roof each time to charge the battery, which greatly reduces work efficiency.

Therefore, before starting work, the user should judge whether the current remaining capacity is sufficient for the planned amount of work, and if it seems insufficient, charge it in advance before starting work ( There is a need.

Based on the above, the remaining capacity display device used for power tools should be able to display the remaining number of times it can be used, such as how many screws can be tightened or how many holes can be drilled. This is effective in determining when to charge the storage battery.

In addition, the remaining capacity display device used in battery-powered electric razors, for example, shows the number of times the shaver can be used, and the remaining capacity in battery-powered cassette players. In the case of a display device, it is effective to be able to display the remaining usable time, such as how many hours the battery can be used, in determining when to charge the storage battery.

However, with the above-mentioned conventional remaining capacity display device, although it displays the remaining capacity of the storage battery itself, it does not display the remaining number of uses or the remaining usage time, so it is difficult to judge the time to charge the storage battery from the display. It wasn't easy.

The present invention was made in view of the above problems, and an object of the present invention is to provide a remaining capacity display device that makes it possible to easily determine when to charge a storage battery.

[Means for Solving the Problem] The remaining capacity display device of the invention as set forth in claim (1) comprises: a remaining capacity detection circuit that detects the remaining capacity of a storage battery connected to a load provided in an electrical device; an arithmetic circuit that calculates the remaining number of times the storage battery can be used from the remaining capacity data from the capacity detection circuit and the amount of electricity discharged from the storage battery when the electrical device is used once; The data for the number of times that can be used is entered, and
It consists of a display section that displays the number of times the device can be used.

The remaining capacity display device of the invention according to claim (2) includes a remaining capacity detection circuit that detects the remaining capacity of a storage battery connected to a load provided in an electrical device; and remaining capacity data from the remaining capacity detection circuit. and an arithmetic circuit that calculates the remaining usable time of the storage battery from data on the amount of electricity discharged per unit time from the storage battery when the electrical equipment is used; It consists of a display section into which data is input and which displays the usable time.

[Operation] According to the remaining capacity display device of the invention described in claim (1), since the remaining number of usable times of the storage battery is calculated and displayed from the remaining capacity, the displayed number of usable times and the scheduled number of times of use are calculated and displayed. Based on the number of uses, it can be easily determined whether or not the storage battery should be charged.

According to the remaining capacity display device of the invention set forth in claim (2), since the remaining usable time of the storage battery is calculated and displayed from the remaining capacity, the displayed usable time and the scheduled usage time can be calculated and displayed. From this, it can be easily determined whether or not the storage battery should be charged.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a circuit block of a remaining power display device incorporated in a battery-powered electric device having a built-in storage battery.

1 is a charging circuit that obtains an alternating current from an alternating current power source AC and outputs a charging current that is a predetermined direct current. 2 is
It is a storage battery, and is connected to the charging circuit 1 via a charging operation switch SW and a resistor R9 for measuring charging current, and is supplied with charging current. Reference numeral 3 denotes a load such as a motor included in the electrical equipment, and is connected to the storage battery 2 via a load operation switch S6 and a resistor 1112 for measuring discharge current.

Reference numeral 4 denotes a remaining capacity detection circuit, which is composed of a microcomputer that serves both as a storage means and an arithmetic means. The remaining capacity calculation circuit 4 is a charging operation switch. is closed, and the voltage generated when the charging current that charges the storage battery 2 flows through the charging current measuring resistor R1 is captured as data on the amount of charging electricity via the A/D converter 5, and is also used in electrical equipment. The voltage generated when the load operation switch S6 is closed and the discharge current discharged from the storage battery 2 flows through the resistor R2 for measuring the discharged current is expressed as A/
The remaining capacity of the storage battery 2 is detected by taking in data on the amount of electricity discharged via the D converter 7, and calculating the data on the amount of electricity regarding charging and discharging according to a pre-stored program.

Below, the content of the arithmetic processing in the remaining capacity detection circuit 4 will be explained.

The remaining capacity detection circuit 4 calculates the integral value of the charging current T0 when the storage battery 2 is charged, and calculates the remaining capacity A1 of the storage battery 2 as follows.
A, = A, 1-1 +I. XdtXKO formula is calculated and stored. In the above equation, dt is the sampling period of the microcomputer, Ai is the current remaining capacity, A++-1 is the remaining capacity one sampling ago, and ■. is the detected value of the charging current determined by the voltage conversion described above. Further, K is a charging efficiency that changes depending on the temperature, and this charging efficiency is calculated from the temperature detected by a temperature sensor 6 arranged to be thermally coupled to the storage battery 2. When the charging operation switch Sl'lc is opened and charging is completed, the remaining capacity detection circuit 4 calculates the remaining capacity A calculated at that time.
In order to detect the remaining capacity of the storage battery 2 when it is discharged, it is stored as the remaining capacity B0.

Further, the remaining capacity detection circuit 4 uses an electric device to calculate the integral value of the discharge current I when the storage battery 2 is discharged, and calculates the remaining capacity B7 of the storage battery 2 as follows: B11=B, -10
It is calculated and stored using the XdtO equation. In the above formula, dt is the sampling period of the microcombiner,
B7 is the current remaining capacity, B11-1 is the remaining capacity before esampling, 1. is the detected value of the discharge current determined by the voltage conversion described above.

Furthermore, when the storage battery 2 is left unused for a certain period of time or more, the remaining capacity detection circuit 4 calculates the differential coefficient of the remaining capacity B1 at that time based on a self-discharge function determined by the storage battery 2 in advance, in order to take into account self-discharge of the storage battery 2. Find Cn, remaining capacity 6
7 is calculated and stored by B@=Bll-I Cn XdtO2. In the above formula, dt is the sampling period of the microcomputer, B7 is the current remaining capacity, and B
*-1 is the remaining capacity before one sampling.

8 is an arithmetic circuit composed of a microcomputer that serves both as a storage means and an arithmetic means. The arithmetic circuit 8 is
When the electrical equipment is used once, data on the consumption current consumed by the load 3, that is, the standard amount of discharged electricity Kt discharged from the storage battery 2, is stored in advance according to the load 3 of the electrical equipment. For example, if the electrical device is an electric screwdriver,
It stores data on the amount of discharged electricity at discharged from the storage battery 2 when drilling one hole, and in the case of an electric razor, data on the amount of discharged electricity discharged during one shave. The arithmetic circuit 8 detects the remaining capacity from the remaining capacity detection circuit 4 ^7. B
The data of A is input, and the data of the remaining capacity A, , B, and the data of the stored electricity quantity Kt are input.
The remaining number of times the storage battery 2 can be used is calculated by performing arithmetic processing according to a pre-stored program.

The contents of the arithmetic processing in the arithmetic circuit 8 will be explained below.

When the data of the remaining capacities A, , B, are sequentially inputted from the remaining capacity detection circuit 4 during charging and discharging of the storage battery 2, the arithmetic circuit 8 calculates the data of the remaining capacities A, , B, and the data stored in advance. Based on the discharge electricity amount and the data of t, the remaining usable number of times that can drive the load 3 with the remaining capacity angle 〇 is N7
, N--An / Xt or N, 1=B, / Xt
Calculate and store using No.2.

9 is a display section consisting of a liquid crystal display, etc., and an arithmetic circuit 8
The data on the number of times that can be used is input and the number of times that can be used is displayed.

Next, data processing operations in the remaining capacity detection circuit 4 and the arithmetic circuit 8 will be explained based on the flowchart in FIG.

Charging operation switch. When charging is started in step 2, the remaining capacity detection circuit 4 takes in the temperature data from the temperature sensor 6, calculates the charging efficiency K using the formula 2, and converts the charging efficiency K into an integral value of the charging current. Multiply the remaining capacity A in step ■. seek. Next, in step (2), the arithmetic circuit 8 calculates, from the data of the remaining capacity A obtained in step (2) and the data of the standard amount of discharged electricity Kt when the electrical equipment is used once, stored in advance. Remaining number of times the storage battery 2 can be used N. is calculated using the formula Nゎ=8,/Kt.

The obtained data of the number of usable times Nn is sent to the display section 9 as display data, and the remaining number of usable times N is displayed in step (2). Display. This display, the remaining capacity A7, and the calculation of the usable number of times N7 are performed using the charging operation switch S! 1. This is done until the charging operation switch S is released.
If it is determined that the remaining capacity A7 is released, the remaining capacity A7 at this point in time is stored as the remaining capacity B0 in step (2).

Next, in step (2), if it is determined that both the charging operation switch SWo and the load operation switch S6 have been left open for a predetermined time T or more (for example, they have been left unattended for 5 days), the discharge characteristics The self-discharge function to be determined is determined in step (2), the differential coefficient 07 in the remaining capacity B, , at that point is determined in step [phase], and the remaining capacity B7 due to self-discharge is determined in step (2). Remaining capacity B. Once determined, the remaining capacity detection circuit 4 determines whether the remaining capacity B9 is zero or not in step @, and if it is determined that it is not zero, one of the operation switches SWC and 5llD is closed. It is determined whether or not it is in step @.

Double operation switch Sll. , 5t11. If it is determined that both are not closed, the process returns to step (■). Ste Nbu ■
If it is determined that the remaining capacity is zero, execution of the program is terminated so that no calculation operation is performed until the start of the next charging.

If operation switch SW or S6 is closed during the remaining capacity calculation due to self-discharge described above, or between the end of charging and the start of remaining capacity calculation due to self-discharge, the closed switch is removed from the charging operation switch in step , or the load operation switch S6. If the charging operation switch S is closed, follow step 1 mentioned above.
Return to Further, if the load operation switch 511ID is closed, the remaining capacity detection circuit 4 detects the remaining capacity B during discharging.
7 is calculated in step ■.Next, in step ■, the storage battery 2 The remaining usable number N1 is calculated using the formula NB, /Kt. The obtained data for the number of times N can be used is
It is sent as display data to the display section 9, and the remaining usable time N7 is displayed in step (2).

Step [phase] is a routine for determining whether the remaining capacity B of the storage battery 2 has become zero. If the determination is YES, the program proceeds to step (2) and ends the program. If the determination is No, it is determined whether the load operation switch 5III1 is in the open state in step [Phase], and if it is NO, the process returns to Step [Phase], and if YES, the process returns to Step ■. .

A second embodiment of the present invention will be described below based on the flowchart of FIG.

The circuit configuration of the remaining capacity display device of this embodiment is the same as that of the first embodiment except for the arithmetic circuit 8, and only the program in the arithmetic circuit 8 has been partially changed.

The arithmetic circuit 8 in this embodiment calculates data on the current consumed by the load 3 per unit time, that is, the standard amount of discharged electricity Kl discharged from the storage battery 2 per unit time when the electrical equipment is used. , is stored in advance according to the load 3 of the electrical equipment.For example, if the electrical equipment is a battery-powered cassette player, data of the amount of discharged electricity Kl discharged from the storage battery 2 after one hour of use is stored. are doing.

The arithmetic circuit 8 receives the remaining capacity A,
Bn data is input, and the remaining capacity A, , Bn
From the data and the pre-stored data of the amount of electricity Kl discharged per unit time, the remaining usable time T7 in which the load 3 can be driven by the remaining capacity A1 is calculated as T, l=A, , / Kl or, T,,=B,/K
The usable time is calculated using the formula 1 and displayed on the display unit 9.

A third embodiment of the present invention will be described below based on the flowchart of FIG.

The remaining capacity display device of the first and second embodiments calculates the remaining usable number of times or usable time based on preset data of the standard amount of discharged electricity of the storage battery 2. . However, the conditions for using the electrical equipment vary widely depending on the work content and the user, and the amount of electricity discharged from the storage battery 2 is also not constant. Therefore, if the data of the amount of electricity discharged from the storage battery 2 is fixed to one standard data,
If the actual amount of electricity discharged from the storage battery 2 deviates significantly from this standard data, there is a problem that the error between the calculated number of usable times or usable time and the actual usable number of times or time becomes large. . The remaining capacity display device of this embodiment is designed to solve this problem, and is designed to reduce the error between the actual remaining capacity and the displayed remaining number of times of use or available time. It is something.

The circuit configuration of the remaining capacity display device of this embodiment is the same as that of the second embodiment, with only a part of the program for the arithmetic circuit 8 being added.

As is clear from the flowchart in FIG. 4, the programs added to the arithmetic circuit 8 are:
phase], [phase] and Φ. When it is determined in step ■ that the load operation switch S6 is closed, the amount of electricity I1 discharged per unit time stored in the arithmetic circuit 8 in step ■,
The discharge time t and the integrated value Ioy of the amount of discharged electricity are cleared to zero. Next, in step O, the remaining capacity B7 is calculated. Furthermore, 1!1. sampled in step ■. Add the amount of electricity to the integrated value I, □ of the amount of discharged electricity, and calculate Step 7 [
Phase] adds the sampling time (It) to the discharge time t. Next, in step [Phase], the remaining usable time T.
It is calculated by dividing the remaining capacity B7 at that time by the previously determined standard discharged electricity amount Kl, and is displayed in step 0. Next, when it is determined in step @ that the load operation switch s6 is opened, the discharged electricity amount I per unit time due to actual use is determined in step @, ID=+air/l.
Calculate using the formula. That is, by dividing the integrated value I,a of the amount of discharged electricity while the load operation switch SWD is closed and the storage battery 2 is discharging by the discharge time t, the amount of electricity discharged per unit time is calculated. It will be done. In step [phase], the discharge electricity quantity ID per unit time due to actual use is stored as 1 in the standard discharge electricity quantity ID.

The standard amount of discharged electricity Kl obtained as described above is used for calculations in the subsequent steps It is calculated based on the amount of electricity discharged during use. This makes it possible to reduce the error between the calculated usable time and the actual usable time.

In this embodiment, the standard amount of discharged electricity Kl is changed each time the storage battery 2 is discharged, but if this standard amount of discharged electricity Kl is determined during the first use, it will not be changed thereafter. You can also do this. That is, from the second time onwards, step [
phase], 0.0. [Phase] and [Phase] may be skipped.

[Effects of the Invention] Since the remaining capacity display device of the present invention is configured as described above, it has the following effects.

The device described in claim (1) calculates and displays the remaining number of times the storage battery can be used from the remaining capacity, so it can be determined whether the remaining number of times the battery can be used satisfies the planned number of times it can be used. This makes it easy to determine when to charge the storage battery.

The device described in claim (2) calculates and displays the remaining usable time of the N battery from the remaining capacity, so it is easy to check whether the remaining usable time is sufficient for the planned usage time. You can easily determine when to charge the storage battery.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of a first embodiment of the present invention, FIG. 2 is a flowchart showing its data processing operation, and FIG. 3 is a data processing operation of a second embodiment of the present invention. Flowchart FIG. 4 is a flowchart showing the data processing operation of the third embodiment of the present invention. 2...Storage battery, 4...Remaining capacity detection circuit, 8...Arithmetic circuit, 9-...Display section.

Claims (2)

[Claims] (1) A remaining capacity detection circuit that detects the remaining capacity of a storage battery connected to a load provided in an electrical device; and the remaining capacity data from the remaining capacity detection circuit, and when the electrical device is used once. An arithmetic circuit that calculates the remaining number of times the storage battery can be used from data on the amount of discharged electricity discharged from the storage battery, and data on the number of times that the storage battery can be used is inputted from the arithmetic circuit.
A storage battery remaining capacity display device consisting of a display unit that displays the number of times the battery can be used. (2) A remaining capacity detection circuit that detects the remaining capacity of a storage battery connected to a load provided in an electrical device, and data on the remaining capacity from the remaining capacity detection circuit, and when the electrical device is used, information from the storage battery. An arithmetic circuit calculates the remaining usable time of the storage battery from data on the amount of electricity discharged per unit time, and the usable time data from the arithmetic circuit is input and displays the usable time. A storage battery remaining capacity display device comprising: a display section;