JP3084903B2 - Devices using secondary battery packs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for loading and using a secondary battery pack having various electric and electronic component loading means, and more particularly to an apparatus having a residual capacity integrating means as a secondary battery pack. It relates to a device to be used.

[0002]

2. Description of the Related Art A device using a secondary battery pack includes, for example, a still camera. That is, in recent years,
In still cameras, there is a remarkable tendency toward computerization. For example, a shutter mechanism, an automatic exposure control mechanism,
Various electric and electronic components such as an auto focus mechanism, an automatic film winding / rewinding mechanism, various function display devices, and the like have been incorporated as load means for a battery power supply. In order to cope with such computerization, it is desired that the battery power supply incorporated in the camera body has a large capacity and a low cost. Recently, a secondary battery such as a rechargeable nickel-cadmium battery has been assembled. It has been considered to use a rechargeable battery pack.

By the way, a still camera as a device using such a secondary battery pack, a secondary battery pack such as a nickel-cadmium battery which is removably mounted and used in the camera,
Furthermore, one of the important things in systematization by combining a charger for the secondary battery pack is to accurately check the remaining capacity of the battery in the secondary battery pack,
Use or charge the camera,
As a countermeasure for this, the following method for confirming the remaining capacity of the secondary battery has been proposed.

That is, a secondary battery such as a nickel-cadmium battery housed in a secondary battery pack is provided with a resistor having a required resistance value in series, and a current flowing therethrough is converted into a voltage and integrated with a time signal. , It is possible to determine the remaining capacity of the battery.

[0005] Specifically, first, when this secondary battery pack is connected to a charger, the charging current is integrated. Conversely, when the secondary battery pack is mounted on a camera and used for photographing, the discharging current is integrated. , And by calculating the difference between them, it is possible to display the remaining battery capacity and to issue a warning.

[0006]

However, in order to display and warn the remaining capacity of the secondary battery by the above-described method, the most important point is the integration accuracy of the charging and discharging currents as described above. However, in this case, in the above-described still camera or the like, a large variation occurs in the current value due to the operation state of various built-in load units, and as a result, it is possible to accurately check the remaining capacity. Could not be said.

For example, if only the discharge is described, for example, in a video camera conventionally known as a device using this kind of secondary battery pack, the discharge current is substantially constant. Since a substantially constant voltage is generated also as the current-voltage conversion resistor described above,
It was possible to relatively easily determine the optimum resistance value of the resistor to be provided in the secondary battery pack.

However, considering the application to a still camera using a film, there are the following problems due to the difference in the type and operation method of the load means as a component thereof. That is, in the still camera, when the power is not turned on, the power is turned on, the display is checked by the display unit, the shutter is opened to expose the film, and then the motor is driven to drive the film. When feeding, etc., the current value to be used is
It will be much different.

[0009] Despite such a large change in the current value, if a current-voltage conversion is performed using a resistor having a single resistance value, the following large errors cannot be avoided. is there.

That is, in order to convert a small current at the time of standby with high accuracy, it is necessary to increase the resistance value. However, with such a large resistance value, the converted voltage overflows when the motor is energized, and the measured voltage is increased. It becomes impossible. Conversely, if the resistance value is optimized for a large current such as when the motor is energized, the voltage conversion value of the standby current is too small, causing an error.

Therefore, in order to incorporate the secondary battery pack into the above-described still camera and use it, the remaining capacity of the secondary battery in the secondary battery pack depends on the usage mode of the plurality of load means as described above. It is necessary to take some measures to prevent the measurement from becoming impossible or causing errors due to large changes in the current value, such as large current and small current, in the resistor provided to display and warn the is necessary.

[0012]

An apparatus using a secondary battery pack according to the present invention in order to meet such a demand includes:
A plurality of types of load means for consuming the discharge current from the secondary battery in the secondary battery pack that can be used repeatedly by charging from the charger are provided, and depending on the magnitude of the load accompanying the selective use of these load means. Means for transmitting a level signal related to the magnitude of the use current value depending on the magnitude of the load, and providing a means for transmitting a level signal corresponding to the magnitude of the use current value according to the magnitude of the load; The amount of charge current from the charger to the battery is integrated by current-voltage conversion, and the amount of discharge current discharged according to the magnitude of the load on the device is integrated by current-voltage conversion, and based on the difference between these two integrated amounts. A charge / discharge integrating means for calculating the remaining capacity of the secondary battery, a means for receiving a level signal from a level signal sending means on the device side, and a level signal obtained by the level signal receiving means. Flip charge and, is provided with a control means for controlling operation of discharge integration means.

According to the present invention, the secondary battery pack is provided with means for receiving a level signal related to the magnitude of the charging current from the charger, and the remaining capacity of the secondary battery in the secondary battery pack is provided. Is configured so that the integration constant can be varied according to the level signal from the device or the charger.

[0014]

According to the present invention, the level of the discharge current according to the magnitude of the load by the load means in the apparatus using the secondary battery pack is provided in the secondary battery pack via the level signal receiving means from the apparatus. Control means to control the operation of the charge / discharge integration means to the required state, and as a result, it is possible to dramatically improve the accuracy of the remaining capacity of the secondary battery obtained by the integration method. Becomes

Therefore, according to the present invention, for example, when the present invention is applied to a camera using a film, the shutter is opened to expose the film when the power is turned on, when the display is checked by the display means, and when the power is turned on and the display is checked. In this case, it is possible to optimize the integral constants for discharge current values that are very different from each other when driving the motor and feeding the film afterwards. It is possible to dramatically improve the accuracy of the remaining capacity of the secondary battery. This is not only a discharge,
By knowing the charging current level signal from the charger for the secondary battery pack, it is also possible to optimize the charging current, and the accuracy of the remaining capacity of the secondary battery obtained by the integration method can be obtained more accurately. Things.

[0016]

1 to 6 show an embodiment in which an apparatus using a secondary battery pack according to the present invention is applied to a still camera incorporating a secondary battery pack. The schematic configuration of a still camera with a built-in secondary battery pack, a secondary battery pack, and a charger for charging a secondary battery is as shown in FIG.

Briefly describing this, reference numeral 1 in FIG. 6 denotes a camera body which is a built-in load device in which various load means such as an electric motor (not shown) for driving automatic film winding and rewinding are incorporated. Reference numeral 2 denotes a secondary battery pack having a built-in secondary battery such as a nickel-cadmium battery which is detachably mounted on the camera body 1 and used.
Charger for the secondary battery.

Reference numeral 4 denotes a photographing lens mounted on the front of the camera body 1. Reference numeral 5 denotes a finder for confirming an image of a subject. Exposure to the film is performed by pressing a shutter button 6 while looking through the finder 5. Is performed. Also,
Reference numeral 7 denotes a secondary battery pack storage section (hereinafter referred to as a storage section) formed at a lower portion of the camera body 1, and the secondary battery pack 2 is removably mounted in the storage section 7.

The secondary battery pack 2 has a structure in which a plurality of secondary batteries such as nickel-cadmium batteries are housed therein and is covered with a resin case. Square head 2 having a shape that is easy to handle
a is formed, and four electrodes 8, 9, 10, 11 are formed on one side of the end of the insertion portion 2b, and a charging jack 12 is provided on the side surface of the insertion portion 2b.

The secondary battery pack 2 is connected to the camera body 1
When the terminals 8 to 11 are loaded into the storage section 7 and assembled.
Contacts the same number of terminals (not shown) provided opposite to each other inside the camera body 1, and power is supplied from the battery inside the secondary battery pack 2 in accordance with the operation of each unit on the camera side.

Here, terminals 8 and 11 are power supply terminals, and terminals 9 and 10 are current level signal terminals which characterize the present invention. Depending on the signal states of these level signal terminals 9, 10, as described later, the secondary battery pack 2
The arithmetic functions within are controlled, the details of which will be described later.

Reference numeral 13 denotes a secondary battery capacity display section (hereinafter referred to as a display section) formed on an end face exposed to the outside when the rectangular head section 2a of the secondary battery pack 2 is mounted on the camera body 1. The unit 13 constantly displays the remaining capacity of the internal secondary battery, and may be performed by, for example, an LCD (liquid crystal) display.

Here, in the present embodiment, such a display unit 13 is an LCD display in which a plurality of segments are formed in a so-called bar graph shape, and is based on a result obtained by a remaining capacity detection unit described later. The remaining length of the secondary battery is indicated by the length of the black segment of the displayed horizontal bar. In addition, as such a display unit 13, a display unit is configured by a light emitting diode array or the like, and light is emitted by performing a push button operation or the like, and the display is performed only for a certain period of time. Good.

When the secondary battery (NiCd battery) in the secondary battery pack 2 as described above is exhausted, it is removed from the housing 7 of the camera body 1 and the charging jack 1 on the side thereof is removed.
2, a charging plug 14 drawn out of the charger 3
And charge the battery. Here, this charger 3
Is used with the AC plug 15 pulled out from one end thereof inserted into a household outlet. The internal circuit (not shown) of the charger 3 generally includes an AC input rectifier circuit, a constant voltage output circuit, a charge completion detection circuit, and the like.

FIG. 1 shows a first embodiment of an electric circuit inside a secondary battery pack 2 according to the present invention. Here, an example of an electric circuit on the camera body 1 side is also shown on the right side in the figure. I have.

More specifically, the charging output from the charger 3 is applied to power supply terminals 20 and 21 provided inside the charging jack 12. The charging current is supplied from the terminal 20 to the diode 22 and the integrating resistor 2.
The secondary battery (NiCd battery) 27 is charged via 3, 24, and 25. Here, the diode 2
Reference numeral 2 is for preventing the secondary battery 27 from being reversely charged and damaged when a voltage having a polarity different from that of the charger 3 is erroneously applied to the terminals 20 and 21.

On the other hand, when the secondary battery pack 2 is mounted on the camera body 1 and used, the discharge current from the secondary battery 27 is supplied to the circuit inside the camera body 1 via the terminals 8 and 11. Is done.

The resistors 23, 24, 25 are connected to terminals 20,
The charging current applied from between the terminals 21 and the discharging current output from the terminals 8 and 11 are converted into a voltage including the direction of the current. Of these resistors 23, 24, 25, the resistors 23,
24 is determined by the state of the transistors 40 and 41 whether or not the resistor 24 is connected in parallel to the resistor 25. The on / off of the transistors 40 and 41 is determined by the terminals 9 and 1
CPU 1 (hereinafter, referred to as a first CPU) 2 in accordance with a level signal from the camera body 1 transmitted through
8, which will be described later in detail.

Further, the current detection circuit 26 (DET)
The direction of the charge / discharge current generated as described above is identified and the amount of the current is grasped, and the result is transmitted to the first CPU 28.
On the other hand, since the clock output of the clock circuit 39 (TIM) is also applied to the first CPU 28, the current capacity is obtained by the calculation with the charge / discharge current value described above.

That is, the charging capacity for the secondary battery 27 is determined from the product of the charging current and the charging time during charging, and the discharging capacity from the secondary battery 27 is determined from the product of the discharging current and the discharging time during discharging. If you find the difference between the former and the latter,
The remaining capacity in the secondary battery 27 is required. The obtained battery capacity value is displayed on the display circuit 29 (DS
P), and is displayed on the display unit 13 using the LCD described above.

Here, the right side from the terminals 8, 9, 10, 11 in the figure is a circuit diagram in the camera body 1. In brief, a CPU (CPU 2; hereinafter, referred to as a second CPU) 33 in the camera body 1 includes a subject luminance detection circuit 30 (B
V) and a sensitivity signal from the film sensitivity detection circuit 31 to perform an operation, and a drive circuit 34 (DV
The photographing information is displayed by the display means 35 via R).

Further, a switch group 3 including a switch interlocked with the operation of the shutter button 6 in the camera body 1 or a sequence state detection switch in the camera body 1
Based on the signal from SW 2 (SW), the opening and closing of the shutter curtain 36, the setting of the aperture 37, the winding of the film by the rotation of the motor 38 and the like are executed via the drive circuit 34.

Further, the second CPU 33 outputs a level signal to the terminals 9 and 10 in accordance with each of the above operation states.

FIG. 2 is a diagram showing the operation current waveform in the camera body 1 and the states of the terminals 9 and 10 and the transistors 40 and 41. Here, the operating current waveform in the camera body 1 is a waveform divided into four types of current values represented by approximately 70, 71, 72, and 73.

First, the current 70 is a standby current when the camera body 1 is not operated, and generally consumes several tens of microamps. The current 71 is a display current when the camera body 1 first performs only a display operation, and generally consumes several tens to one hundred and several tens of milliamps. Further, a current 72 is an exposure current when the diaphragm 37 and the shutter curtain 36 are operated to perform exposure, and generally consumes about one hundred and several tens of milliamps. Finally, the current 73 is a motor current when the film winding motor 38 is rotated, and generally consumes several hundred millimeters to several amperes.

Then, the second CPU 33 changes the levels of the terminals 9 and 10 as shown in the figure according to the above four types of operations. For example, for the exposure current 72, the terminals 9 and 10 are set to L and H, respectively.

The first CPU in the secondary battery pack 2
Reference numeral 28 corresponds to the ON / OFF states of the transistors 40 and 41 in accordance with the states of the terminals 9 and 10 as shown in FIG. For example, the transistors 40 and 4 are adjusted in accordance with L and H of the terminals 9 and 10 when the exposure current 72 is generated.
1 is turned off and on (OFF, ON), respectively.

Therefore, the combination of the resistance values for converting the discharge current into a voltage is as shown in the figure. For example, when the exposure current 72 is generated, the combination is performed by the parallel circuit of the resistors 24 and 25. is there.

In the case of a small current value such as the standby current 70, the terminals 9 and 10 become L and L, whereby the transistors 40 and 41 are turned off and the resistors 23 and 24 are disconnected from the circuit. And while the display current is 71,
When the motor current 73 has the largest current value in the parallel circuit of the resistors 23 and 25, the three resistors 23,
24 and 25 are executed in parallel.

In other words, a level signal is sent from the terminals 9 and 10 in accordance with the magnitude of the discharge current on the camera body 1 side, and the three resistors 23, 24 and 2 in the secondary battery pack 2 are sent.
5 is selectively combined. When the current is small, only one resistor 25 is used. When the current is large, a parallel circuit of three resistors 23, 24, and 25 is used. In such a case, the resistor 23 or 24 is selectively arranged in parallel with the resistor 25.

That is, according to this embodiment, since the level of the discharge current can be known, when the present invention is applied to a camera using a film, the power is turned on at the time of standby when the power is not turned on and the display by the display means is performed. When checking the
When exposing the film by opening the shutter and then driving the motor to feed the film, it is possible to optimize integration constants for discharge current values having very different values. Therefore, the accuracy of the remaining capacity required by the integration method can be significantly improved.

FIG. 3 shows an example of a processing program in the second CPU 33 in the camera body 1. Note that this processing program is repeatedly executed while the power is supplied to the second CPU 33 from the terminal 8.

Each step of the processing program will be described below in order. Step 45: First, both terminals 9 and 10 are set to the initial value L
And The secondary battery pack 2 recognizes the standby state based on this signal.

Step 46: It is determined whether or not the display mode is instructed by half-pressing the shutter button 6. And when the shutter button 6 is not pressed,
It is determined that it is in the standby state, and the process returns to step 45.

Step 47: When it is determined that the shutter button 6 is half-pressed, the mode is shifted to the display mode.
Are set to H and L, respectively. The secondary battery pack 2
Based on this signal, the display mode is recognized. Step 48: A proper exposure condition is calculated by calculating the luminance signal from the luminance detection circuit 30 and the sensitivity signal from the sensitivity detection circuit 31. Step 49: The appropriate exposure conditions and the like are displayed on the display means 35.

Step 50: It is determined whether or not a mode for executing the exposure operation is instructed by fully pressing the shutter button 6. If it has not been fully pressed, the process returns to step 46, and the above-described processing steps 46 to 50 are repeated.

Step 51: When fully depressed, the mode shifts to the exposure mode, and first, terminals 9 and 10 are set to L and H, respectively.
Set to. The secondary battery pack 2 recognizes the exposure mode based on this signal. Step 52; Then, as is well known, a mirror (not shown) is raised and retracted from the photographing optical path. Step 53: Next, the aperture 37 is set to a predetermined value. Step 54: Then, the shutter 36 is opened for a predetermined time,
The film is exposed.

Step 55: When the above operation is performed, the mode is shifted from the exposure mode to the film winding mode. First, both terminals 9 and 10 are set to H. The secondary battery pack 2 recognizes the film winding mode based on this signal. Thereafter, the process returns to step 46,
The above processing is repeatedly executed.

As is clear from the above description,
Each time it switches to the four types of current states shown in FIG.
The state of the terminals 9 and 10 is switched, and the current level at that time is transmitted to the secondary battery pack 2.

FIG. 4 shows the first CPU 2 in the secondary battery pack 2.
8 illustrates a processing program. These processes are repeatedly executed while the secondary battery 27 (secondary battery pack 2) is incorporated in the camera body 1.

Each step of the processing program will be described below in order. Step 60: Determine whether the terminal 9 is at H level. Step 61: Since the terminal 9 is at H level, the transistor 4
Turn on 0. Thus, at least the resistors 23 and 25 are connected in parallel. Step 62: Since the terminal 9 is at L level, the transistor 4
Turn off 0. Thus, at least the resistor 23 is disconnected from the circuit.

Step 63: It is determined whether the terminal 10 is at H level. Step 64: Since the terminal 10 is at H, the transistor 41 is turned on. Thus, at least the resistors 24 and 25 are connected in parallel. Step 65: Since the terminal 10 is at L, the transistor 41 is turned off. This disconnects at least the resistor 24 from the circuit.

Step 66: The detection circuit 26 detects the voltage generated in the resistor network whose connection relation has been determined as described above, and the first CPU 28 takes in the voltage. Step 67: The time is calculated based on the time signal output from the clock circuit 39.

Step 68: Based on the two signals obtained in steps 66 and 67, a current-time product is calculated and subtracted from the past remaining capacity to obtain the current remaining capacity. Step 69: A display signal is output to the display circuit 29 to perform display on the LCD display unit 13.

FIG. 5 shows a second embodiment of the electric circuit in the secondary battery pack 2 according to the present invention. Here, a circuit example on the charger 3 side is also shown on the left side in the figure.

This embodiment is based on the premise that there are a plurality of types of chargers 3 and that their charging currents are different for each model. Moreover, although it is a single charger 3,
It is possible to cope with a case where the charging current is not uniform and changes with time. Here, components having the same functions as those in FIG. 1 described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference from FIG. 1 described above in this example is that terminals 42 and 43 are newly added to the charging jack 12 for the charger 3.
And terminals 9 and 10 are connected in parallel, respectively.

Of course, a similar terminal is also provided and connected to the charging plug 14 on the charger 3 side.
The terminal 42 is connected to the circuit on the terminal 20 side in the charger 3, and the terminal 43 is connected to the circuit on the terminal 21 side in the charger 3. In the figure, reference numeral 80 denotes a rectifier converter connected to the AC plug 15, and a circuit for outputting a charging current from the rectifier converter 80 to the terminals 20, 21 is configured.

According to the above configuration, the charger 3
Since the voltage conversion of the charging current in the secondary battery pack 2 when is connected is performed based on the level signals from the terminals 42 and 43, the integration of the charged amount can be performed with high accuracy.

That is, according to the present invention, not only the discharge on the camera body 1 side using the secondary battery pack 2 as described above, but also the charger 3 as described in this embodiment.
By knowing the charging current level signal from, the charging current can be optimized, and the remaining capacity accuracy required by the integration method can be improved.

It should be noted that the present invention is not limited to the structure of the embodiment described above, and the shape of each part including the secondary battery pack 2,
It goes without saying that the structure and the like can be appropriately modified and changed.

Further, in the above-described embodiment, an example in which the present invention is applied to a still camera as an apparatus using the secondary battery pack 2 has been described. However, the present invention is not limited to this. The present invention can be applied to various types of electrical equipment and devices having a plurality of load means and having large and small currents to be used. In short, any device or device that uses the secondary battery pack 2 provided with the remaining capacity integrating means may be used.

[0063]

As described above, according to the apparatus using the secondary battery pack according to the present invention, a plurality of batteries that consume the discharge current from the secondary batteries in the secondary battery pack that can be repeatedly used by charging are used. It is configured such that the used current value differs depending on the magnitude of the load accompanying the selective use of the type of load means, and means for transmitting a level signal related to the magnitude of the used current value is provided. In response to the above, the amount of charge current from the charger to the secondary battery and the amount of discharge current discharged according to the magnitude of the load on the device side are integrated in the secondary battery pack by current-voltage conversion. The charge / discharge integrating means for calculating the remaining capacity of the secondary battery based on the difference between the two integrated amounts, the means for receiving a level signal from the level signal transmitting means on the device side, and the level signal receiving means. Level signal Control means for controlling the operation of the charge / discharge integrating means, the discharge obtained in accordance with the magnitude of the load by the load means in the device using the secondary battery pack despite the simple configuration. Depending on the level of the current, the operation of the charging / discharging integration means can be controlled to a required state by the control means in the secondary battery pack. As a result, the remaining capacity of the secondary battery obtained by the integration method There is an excellent effect of dramatically improving accuracy.

Further, according to the present invention, the secondary battery pack is provided with a means for receiving a level signal related to the magnitude of the charging current from the charger, or the remaining battery power in the secondary battery pack is reduced. By configuring the charge / discharge integrating means for calculating the capacity so that the integration constant can be varied according to the level signal from the device or the charger, the above-mentioned effect can be further exhibited.

For example, when the present invention is applied to a camera using a film, the shutter is opened to expose the film when the power is turned on, when the display is checked by the display means, and when the power is turned on. Time,
After that, it is possible to optimize the integration constants for discharge current values that are very different from each other, for example, when driving a motor to feed a film, and thereby, the residual of the secondary battery obtained by the integration method. It is possible to dramatically improve the capacity accuracy.

Further, this can be achieved not only by discharging but also by knowing the charging current level signal from the charger for the secondary battery pack, so that the charging current can be optimized. This has the advantage that the remaining capacity accuracy of the secondary battery can be further improved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an apparatus using a secondary battery pack according to the present invention, and is an electric circuit diagram of a secondary battery pack and a camera body using the secondary battery pack.

FIG. 2 is a time chart for explaining an operation current waveform and a level signal terminal in the camera body and a control operation by the terminal signal.

FIG. 3 is a flowchart illustrating a processing program by a CPU in the camera body.

FIG. 4 is a flowchart illustrating a processing program by a CPU in a secondary battery pack.

FIG. 5 is an electric circuit diagram of a secondary battery pack and a charger used for the secondary battery pack.

FIG. 6 is a schematic perspective view showing a schematic configuration of a camera body, a secondary battery pack, and a charger suitable for applying the present invention.

[Explanation of symbols]

 Reference Signs List 1 Camera body (device using secondary battery pack) 2 Secondary battery pack (Nicad battery pack) 3 Charger (device using secondary battery pack) 7 Secondary battery pack storage section 8 Power supply terminal 9 Level signal Terminal 10 Level signal terminal 11 Power supply terminal 12 Charging jack 13 Secondary battery capacity display 14 Charging plug 15 AC plug 20 Power supply terminal 21 Power supply terminal 23 Integrating resistor 24 Integrating resistor 25 Integrating resistor 26 Current detection Circuit 27 Secondary battery 28 CPU (control means) 29 Display circuit 30 Subject luminance detection circuit 31 Film sensitivity detection circuit 32 Switch group 33 CPU 34 Drive circuit 36 Shutter curtain 37 Aperture 38 Motor 40 Transistor 41 Transistor 42 Level signal terminal 43 Level signal Terminal 80 Rectifier converter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-74526 (JP, A) JP-A-56-28476 (JP, A) JP-A-56-48075 (JP, A) 29079 (JP, A) JP-A-4-357480 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B ^7/ 00-7/28 G03B 17/00-17/02 H01M 10/42-10/48

Claims (3)

(57) [Claims] 1. A plurality of types of secondary battery packs having a secondary battery that can be used repeatedly and used in combination with a charger for charging the secondary battery, and consuming discharge current from the secondary battery. An apparatus using a secondary battery pack including a load unit and configured to have a different current value depending on the magnitude of a load accompanying the selective use of the load unit, the use of the secondary battery pack The apparatus is provided with means for transmitting a level signal relating to the magnitude of the current used depending on the magnitude of the load accompanying the selective use of the load means, and the secondary battery pack comprises: The amount of charging current from the charger to the battery is integrated by current-to-voltage conversion, and the amount of discharge current discharged according to the magnitude of the load on the device is integrated by current-to-voltage conversion. Charge / discharge integrating means for calculating the remaining capacity of the secondary battery based on: a means for receiving a level signal from a level signal sending means on the device side; and a means for receiving a level signal obtained by the level signal receiving means. And a control means for controlling the operation of the charge / discharge integrating means. 2. The apparatus using the secondary battery pack according to claim 1, wherein the secondary battery pack is provided with means for receiving a level signal related to the magnitude of the charging current from the charger. A device that uses a secondary battery pack. 3. An apparatus using the secondary battery pack according to claim 1 or 2, wherein the charge and discharge currents of the secondary batteries are integrated in the secondary battery pack to calculate a remaining capacity. An apparatus using a secondary battery pack, wherein the integrating means is configured to be capable of changing an integration constant according to a level signal from the apparatus or the charger.