JPH11111350A - Battery and electronic apparatus with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery and an electronic apparatus with it, which can change a charging voltage by itself in accordance with a temperature and can prevent an internal short-circuit condition by prolonging its life time. SOLUTION: A battery pack 7200 has a secondary battery cell 401, a temperature sensor 402 for measure a temperature of the second battery cell 401 or a temperature in the neighborhood of the second battery cell 401, a voltage control part 503 to control a charging voltage, when charging the second battery cell 401 and a container 201 for containing the second battery cell, the temperature sensor 402 and the voltage control part 403, and the voltage control part 403 controls the charging voltage of the second battery cell 401 according to the temperature detected by the temperature sensor 402.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery and an electronic device having the battery.

[0002]

2. Description of the Related Art In recent years, many portable electronic devices have been released, and advanced electronic devices equipped with a CPU (Central Processing Unit) have appeared. Among portable electronic devices, for example, a portable computer includes a main body and a display unit thereof, and the display unit can be opened and closed with respect to the main body via a hinge. A typical example of such a portable computer is a computer called a notebook personal computer.

An external battery may be set to drive this kind of portable computer. The reason for using an external battery in this manner is that a portable computer is becoming thinner, and a battery pack such as a lithium ion battery is usually used. A battery pack detachable from a portable computer is disclosed in JP-A-4-331291. The battery pack disclosed in this publication incorporates a temperature sensor in a computer, and controls the state of charge of an external battery pack according to the temperature measured by the temperature sensor.

It is necessary to control the state of charge of a secondary battery such as a lithium ion secondary battery in accordance with the temperature for the following reasons. If the temperature of the battery pack itself or its ambient temperature rises above a certain temperature while charging the secondary battery, an internal short-circuit state occurs and the leakage current increases. Also, the life of the battery pack itself may be shortened. Therefore, assuming that the temperature of the battery pack or the ambient temperature has reached a certain temperature, for example, 45 ° C. or higher, it is conceivable to lower the charging voltage during charging in advance to lower the charging speed. Then, full charge (full charge) cannot be performed in a short time.

[0005] The lithium ion secondary battery has a large battery capacity, but has a disadvantage that it is weak in charging at a high temperature. Particularly, a lithium ion secondary battery using a graphite-based material for the cathode material may deteriorate the cycle life of the battery when charged at a high temperature, increase the leakage current of the battery, and cause an internal short circuit.

[0006]

As described above, when the atmosphere of the battery pack exceeds a certain temperature or the temperature of the battery pack itself reaches that temperature, there is a problem that it is difficult to charge the battery pack with a normal charging voltage. . Also, in the above-mentioned publication, since a temperature sensor is provided on the computer side, if a battery pack is connected to a computer without a temperature sensor, the charging voltage of the battery pack is changed according to the temperature. Can not. Accordingly, the present invention has been made to solve the above problems, and to provide a battery capable of changing a charging voltage in accordance with a temperature by a battery itself, extending a life and preventing an internal short-circuit state, and an electronic device having the battery. It is an object.

[0007]

According to the present invention, there is provided a secondary battery cell, and a temperature sensor for measuring a temperature of the secondary battery cell or a temperature near the secondary battery cell.
When charging a secondary battery cell, the battery has a voltage control unit that controls a charging voltage, a secondary battery cell, a temperature sensor, and a container that houses the voltage control unit, and a temperature detected by the temperature sensor. Accordingly, the voltage control unit controls the charging voltage of the secondary battery cell, and is achieved by a battery.

In the present invention, the temperature sensor measures the temperature of the secondary battery cell or the temperature near the secondary battery cell. The voltage control unit controls a charging voltage when charging the secondary battery cell. The container contains a secondary battery cell, a temperature sensor, and a voltage controller. That is, the temperature sensor is disposed in the container of the battery pack. Thereby, the voltage control unit can control the charging voltage of the secondary battery cell according to the temperature of the secondary battery detected by the temperature sensor.
Using the temperature sensor on the battery side, the charging voltage of the secondary battery cell can be controlled according to the temperature detected by the temperature sensor. Thus, even if there is no temperature sensor on the side of the electronic device to which the battery is to be connected, it is possible to easily control the charging voltage related to the temperature of the battery.

[0009] The object of the present invention is to provide a camera comprising:
The main body includes a battery which is detachably attached to an electronic device having a display unit which can be opened and closed. The battery includes a secondary battery cell and a temperature of the secondary battery cell or a secondary battery. A temperature sensor for measuring the temperature in the vicinity of the cell, a voltage controller for controlling the charging voltage when charging the secondary battery cell, and a container containing the secondary battery cell, the temperature sensor, and the voltage controller The voltage control unit controls the charging voltage of the secondary battery cell according to the temperature detected by the temperature sensor, and is achieved by an electronic device having a battery.

[0010] Thereby, the 2 detected by the temperature sensor.
The voltage controller can control the charging voltage of the secondary battery cell according to the temperature of the secondary battery. According to the temperature detected by the temperature sensor using the battery-side temperature sensor, 2
The charge voltage of the secondary battery cell can be controlled. Therefore, even if there is no temperature sensor on the side of the electronic device to which the battery is to be connected, it is possible to easily control the charging voltage related to the temperature of the battery of the electronic device.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description. FIG. 1 shows an example of a battery of the present invention and an electronic device having the battery. The electronic device in FIG. 1 is a portable computer 100. The portable computer 100 includes a main body 2, a display unit 3, a keyboard 4, hinges 1A and 1B surrounded by A and B regions, a battery pack (battery) 200, and the like.

The main body 2 has the above-described keyboard 4 and other pointing devices 5 and the like, and the display section 3 can employ, for example, a liquid crystal display (LCD). The display unit 3 includes hinges 1A and 1B with respect to the main body 2.
Is mounted so that it can be opened and closed (folded) in the direction of arrow R. Although not shown in FIG. 1,
For the main body 2, a device or the like to which a mouse or the like as an external pointing means is externally attached can be set. The main body 2 has a power lamp PL, a battery lamp BL, and a message lamp ML. The battery lamp BL indicates the remaining battery level of the battery pack 200.

FIG. 2 is a view of the display unit 3 of the electronic apparatus of FIG. 1 in a state where the display unit 3 is folded about the center axis CLC with respect to the main body 2 and viewed from the arrow SD. 2, a power switch 40 and other switches 41 and 42 are arranged on a side surface 2S of the main body 2. A slot 43 for inserting an electronic card (PC card) is provided on the side surface 2S.
Is provided. The thickness of the tip of the main body 2 and the thickness of the tip of the display unit 3 shown in FIG. 2 are denoted by reference numerals t1 to t4. For example, the thickness t1 is 1.2 mm, and the thickness t2 is 1.
0 mm, thickness t3 is 1.0 mm, thickness t4 is 1.2 mm
It is set very thin, such as.

As shown in FIGS. 1 to 3, a characteristic feature is that the battery pack 200 is disposed between the hinges 1A and 1B. Preferably these hinges 1
The central axis CLC corresponding to the central axes of A and 1B corresponds to the central axis of the battery pack 200. That is, the center axis of the battery pack 200 and the center axes of the hinges 1A and 1B coincide. The battery pack 200 can be detachably and mechanically held on the main body 2 and can also be detachably electrically connected.

As shown in FIGS. 2 and 3, the battery pack 200 has a rear end 2F of the main body 2 and a rear end 3F of the display section 3.
, The diameters of the battery pack 200 and the hinges 1A and 1B are set to be substantially the same,
Moreover, the diameter K is set to be substantially the same as the thickness M when the display unit 3 is folded with respect to the main body 2.
Thus, the capacity of the battery pack 200 can be increased while the size (thickness M) of the portable computer 100 is reduced as much as possible, and the diameter K of the hinges 1A and 1B can be made as large as possible. ,
1B can have improved durability.

As shown in FIGS. 4, 5 and 6, the battery pack 200 is disposed at the rear end 2F of the main body 2 and between the hinges 1A and 1B as described above.
The battery pack 200 has a shape as shown in FIGS. This battery pack 200
For example, a secondary battery such as a lithium ion secondary battery can be used, and the battery pack 200 has a case 201. The case 201 is made of, for example, plastic molding, and one or a plurality of battery cells are arranged in the case 201. The case 201 has mechanical attachment portions 202, 202, grooves 203, 203, and electrical connection terminals 204.

As shown in FIGS. 8 and 10, the case 201 has two grounding portions 205, 205. The grounding portions 205, 205 prevent the battery pack 200 from slipping on a support surface such as a desk. It is for supporting and is made of rubber, for example. The grooves 203, 203 are
01 are formed along the horizontal direction N in FIG. Also, the mounting portions 202, 202
On the contact surface 209 side of the case 201, it is provided so as to protrude. A male electrical connection terminal 204 is provided on the contact surface 209 between the mounting portions 202. On the other hand, the rear end portion 2F of the main body 2 has the mounting portion 2
Concave portions 302, 302 corresponding to 02, 202 are formed. The main body 2 has an electric connection terminal 304 for electrically fitting the electric connection terminal 204.

On the main body side of the hinges 1A and 1B, there are provided projections 303 for guiding. By inserting these protrusions 303 into the grooves 203 at both ends of the battery pack 200, the battery pack 200 can be guided and fitted in the direction of the arrow N1. Thus, the battery pack 200 can be firmly detachably fixed to the main body 2 side by using the grooves 203, 203, the mounting portions 202, 202, and the electric connection terminals 204. And supply power to one.

FIG. 14 shows the battery of the present invention and the above-described computer 100 to which the battery is attached. The computer 100 and the battery pack as a battery are connected to the electric connection terminals 204 and 304 shown in FIG.
Thus, it can be detachably electrically connected. The battery pack 200 has a case (container) 201, in which components described below are accommodated. In this case 201, one or a plurality of battery cells (secondary battery cells) 401, a temperature sensor 402, and a voltage control unit 403 are incorporated. Case 20
As shown in FIG. 7 and the like, 1 is a substantially cylindrical, long plastic material, for example, in which one or a plurality of battery cells 401 are electrically arranged in series or in parallel. As the battery cell 401, for example, a lithium ion secondary battery can be used.
The cathode material of the secondary battery 401 is, for example, a graphite-based material.

The temperature sensor 402 is a sensor that measures the temperature of the battery cell 401 itself or the temperature near or near the battery cell in the case 201. Voltage control unit 40
Reference numeral 3 is for controlling the charging voltage for the battery cell 401 in accordance with the temperature measured by the temperature sensor 402. The voltage control section 403 has a controller 404 and a semiconductor switching element 405. The controller 404 receives the temperature information signal T from the temperature sensor 402.
By receiving S, on / off control of the switching element 405 is performed. The controller 404 also stabilizes the operation of the switching element 405 by feeding back the switching voltage SV output from the switching element 405.

The switching element 405 is arranged between the electric connection terminal 204 and one end of the battery cell 401. The electric connection terminal 204 is an input / output terminal for the battery cell 401. The temperature sensor 402 is a controller 4
04. The switching element 405 is connected to the controller 404. Switching element 4
The switching voltage SV on the output side of 05 is returned to the controller 404 for feedback as described above. The positive terminal and the negative terminal of the battery cell 401 are connected to the electric connection terminals 204, 204. As described above, the case 201 of the battery pack 200 is characterized in that not only the battery cell 401 and the voltage control unit 403 but also the temperature sensor 402 is built therein.

FIG. 15 shows the battery pack 200 of FIG.
, The controller 404 of the voltage control unit 403
An example is shown in which on / off charging is performed on the battery cell 401 by turning on / off the semiconductor switching element 405 based on the temperature information signal TS of the temperature sensor 402. The input voltage (charging voltage) to the battery cell 401 is supplied from the electric connection terminal 304 of the main body 2 of the computer 100 to the electric connection terminal 204 of the battery pack 200.

In FIG. 15, as described above, the battery cells 40
FIG. 15A shows an example of an intermittent charging (on / off charging) method, and FIG. 15A shows a relationship between an on / off state of the semiconductor switching element 405 and time, and FIG.
Indicates a temporal change in the charging voltage of the battery cell. Temperature information signal TS detected by normal temperature sensor 402
However, based on a predetermined temperature, for example, 45 ° C., the temperature sensor 4
When the temperature information signal TS detected by the temperature sensor 02 is 45 ° C. or higher, the charging voltage (voltage per battery cell) is increased each time the temperature rises, as in the following specific examples of temperature and charging voltage. , By using the semiconductor switching element 405.

[Table 1]

In FIG. 15, when the semiconductor switching element 405 is turned on, the charging voltage of the battery cell 401 gradually increases, and at a certain time T1, the semiconductor switching element 405 is turned off, and this on / off is repeated. At this time, the ON time t1 is set longer than the OFF time t2, that is, the duty ratio (t1 / t2) is set to be large. By doing so, the charging voltage fluctuates relatively, but gradually approaches a certain value, for example, 4.15V. And the semiconductor switching element 405
The on / off duty ratio is changed so that the on time t3 is shorter than the off time t4 as shown in FIG. 15A, that is, the duty ratio is reduced, so that the charging voltage becomes a certain value of the target voltage. It becomes PV.

FIG. 16 further shows in detail the state of the charging voltage of FIG. 15B, and FIG.
The change of the charging voltage in (B) is shown in an enlarged manner. Assuming that the upper limit of the target charging voltage PV is, for example, 4.20 V and the lower limit is 4.10 V, the charging voltage curve once reaches the upper limit and then changes from the point P1 to the point P2 due to a change due to the internal resistance. Due to a change due to discharge or diffusion, the temperature gradually decreases and moves to point P3. At this point P3, the semiconductor switching element 4
Since the switch 05 is turned on again, the charging voltage rises to the point P4 due to the change due to the internal resistance, and gradually increases from the point P4 to the point P5. By repeating such a change, the charge voltage approaches the target charge voltage PV as shown in FIG. If the on / off ratio of the semiconductor switching element 405 is set, that is, if the duty ratio of the semiconductor switching element 405 occupies a large proportion of the on-time, the charging voltage increases. Can be smaller.

As shown in the specific example of the temperature and the charging voltage,
Temperature information signal TS measured by temperature sensor 402 in FIG.
Is 45 ° C. or less, the charging voltage (voltage per cell) for the battery cell 401 is determined by the controller 404 performing on / off control of the switching element 405.
4. Set to 20V. Otherwise, when the temperature sensor 402 measures 45 ° C. to 50 ° C. as the temperature information signal TS, the temperature of the battery cell 401 itself or the battery cell 40
Assuming that the temperature near 1 has risen, the controller 404 controls the semiconductor switching element 405 to lower the charging voltage to 4.15V. 50 ° C to 55
When the temperature reaches ° C, the charging voltage is reduced to 4.10V, and when the temperature reaches 55 ° C to 60 ° C, the charging voltage is reduced to 4.05V.

By the function of the semiconductor switching element 405, the charging voltage for the battery cell 401 can be reduced according to the temperature condition. When the temperature rises, the semiconductor switching element 405 changes (decreases) the charging voltage in a manner also called intermittent charging or pulse charging for the battery cell 401. By doing so, a battery cell 4 such as a lithium ion secondary battery can be obtained.
01 eliminates the disadvantage that the capacity is large but weak in charging at a high temperature state, for example, even in a lithium ion battery using a graphite-based material for the cathode material, to prevent a decrease in the cycle life of the battery when charging at a high temperature, The internal short-circuit state can be released by reducing the leakage current of the battery.

Next, referring to FIGS. 17 and 18, another embodiment of the battery of the present invention and an electronic apparatus having the battery will be described. The portable computer 100 as the electronic device shown in FIG. 17 is the same as the example in FIG.
The battery pack 200 is the same as the battery pack 20 shown in FIG.
Unlike the case 0, the case (container) 201 contains a battery cell 401, a temperature sensor 402, and a voltage control unit 503. Electric connection terminal 20 of battery pack 200
Reference numerals 4 and 204 are connected to the positive and negative poles of the battery cell 401. However, the electric connection terminal 204 and the battery cell 401
A voltage control section 503 is arranged between the one electrode section. This voltage control unit 503 includes a controller 504
And a voltage drop element 505 and a changeover switch 506.

As the changeover switch 506, for example, a semiconductor changeover switch can be used. The changeover switch 506 is connected to the controller 504, and the voltage drop element 505 is also connected to the control terminal 504a of the controller 504. Voltage drop element 5
05 is arranged between one electrical connection terminal 204 and the contact 506a of the semiconductor changeover switch 506. Another contact 506b of the changeover switch 506 is
It is connected to the electric connection terminal 204. An output terminal 506 c of the changeover switch 506 is connected to one electrode of the battery cell 401. And the output side terminal 506
The voltage RV of c can be fed back to the controller 504. The temperature sensor 402 can send a temperature information signal TS to the controller 504.

When the changeover switch 506 is switched to the contact 506a, the electric contact 204, the voltage drop element 505 and one electrode of the battery cell 401 can be electrically connected.
On the other hand, the changeover switch 506 is connected to the other terminal 5.
When switched to 06b, the electrical connection terminal 204 is directly connected to one electrode of the battery cell 401 through the changeover switch 506 through the semiconductor switching element 605. That is, the voltage drop element 505 is not connected. Note that the semiconductor switching element 605 is connected to the electric connection terminal 20.
4, the semiconductor switching element 605 is a simple on / off switch for shutting down the electrical connection of the battery cell 401 to the computer 100 side (that is, disconnecting the electrical connection). is there. This semiconductor switching element 605
Is normally turned on by a command from the controller 504, but is turned off when the electric connection of the battery cell 401 is cut off.

FIG. 18 shows an example of the voltage drop element 505 of FIG. In the voltage drop element 505, a transistor T1 is arranged between the electric connection terminal 204 on the computer 100 side and the battery cell 401 side. The base of this transistor and the control terminal 5 of the controller 504
Another transistor T2 is arranged between the transistors 04a. The transistor T2 operates the transistor T1, and turns on the transistor T2 in response to a signal from the controller 504 input to the control terminal 504a. The voltage drop element 505 includes two transistors T1,
T2, the electric connection terminal 204 and the battery cell 40
1, the voltage Vce between the collector and the emitter of the PNP transistor T1 disposed between the PNP transistors 1 becomes a voltage corresponding to the voltage drop value. In general, the collector /
The voltage between the emitters is about 0.05 V to 0.2 V and is determined by the type of the transistor, the ratio of the base current to the collector current, and the like. Therefore, by setting the base resistance R that determines the type of the transistor and the base current, The voltage drop value can be set arbitrarily. For example, battery cell 401
Is charged by the transistor T1.
It can drop from 20V to 4.10V.

In FIG. 17, when the temperature information signal TS detected by the temperature sensor 402 is lower than 45 ° C., for example, the charging current is 4.20 V, so that the changeover switch 506 is on the contact 506b side and A terminal 204 is a semiconductor switching element 605, a changeover switch 506.
A charging voltage is supplied to the battery cell 401 via the.
On the other hand, when the temperature information signal TS detected by the temperature sensor 402 exceeds 45 ° C. and becomes, for example, 51 ° C., the controller 504 switches the changeover switch 506 to the contact 506a side, and thereby the electric connection terminal 204 Charging voltage applied from the semiconductor switching element 60
5 through 4.20 V to 4.10 at the voltage drop element 505.
After the voltage is dropped to V, it is supplied to the battery cell 401 via the changeover switch 506. Note that specific examples of the temperature and the charging voltage are the same as those already described in the example of FIG.

Although one voltage drop element is used, if a plurality of types of voltage drop elements are provided in parallel, for example, 0.50
V, 0.10V, 0.15V, etc.
By selecting the corresponding voltage drop element by the controller 504 according to the temperature, a plurality of types of charging voltages that can be applied to the battery cell 401 can be set.

As described above, in the embodiment of the present invention, charging can be reliably performed even when the battery pack 200, which is also called a battery pack, is at a relatively high temperature. On the electronic device side to which the battery pack 200 is connected, the same voltage for charging the battery cells can be applied without any change as before. That is, the charging voltage applied from the electronic device 100 such as a computer may be constant even if the temperature inside the battery pack 200 changes. That is, a constant voltage may be applied regardless of the temperature. Then, the battery cell 40
Even if the battery is charged at a high temperature, the battery leakage current can be reduced without deteriorating the cycle life of the battery,
An internal short circuit can be avoided.

FIG. 19 shows an example of a voltage drop of a lithium ion secondary battery when a graphite material is used as a cathode material. A lithium ion secondary battery using a graphite-based cathode material has the feature that it can maintain a substantially constant voltage until a certain time, but as described above, when the temperature rises, it is necessary to consider the charging voltage value. is there.

The present invention is not limited to the above embodiment. In the illustrated embodiment, a so-called portable computer is used as an example of the electronic device to which the hinge of the present invention is applied. However, the present invention is not limited to this, and other types of electronic device may be used. The electronic device of the present invention can be applied to electronic devices that generate various heat, such as portable information terminals, mobile phones, and wireless devices. In the above embodiment, the battery pack as a battery pack includes
Although a lithium ion secondary battery is used as the battery cell, another type of secondary battery may be used.

[0037]

As described above, according to the present invention,
The battery itself can change the charging voltage in accordance with the temperature, thereby extending the life and preventing an internal short-circuit state.

[Brief description of the drawings]

FIG. 1 is an exemplary perspective view showing an embodiment of an electronic device having a battery of the present invention.

FIG. 2 is a side view of a computer which is the electronic apparatus of FIG.

FIG. 3 is a plan view showing a state in which a display unit is closed with respect to the main body of the electronic apparatus of the present invention.

FIG. 4 is a plan view showing a main body and a battery pack.

FIG. 5 is a view showing a main body and a battery pack, and showing a state where a display unit is removed.

FIG. 6 is a partially omitted perspective view showing a main body, a display unit, and a battery pack.

FIG. 7 is a perspective view showing a connection relationship between a battery pack and a main body.

FIG. 8 is a front view of the battery pack.

FIG. 9 is a plan view of the battery pack.

FIG. 10 is a sectional view taken along line CC in FIG. 9;

FIG. 11 is a sectional view taken along line BB in FIG. 9;

FIG. 12 is a sectional view taken along line DD in FIG. 9;

FIG. 13 is a side view of the battery pack seen from the direction E in FIG. 9;

FIG. 14 is a diagram showing a connection example of a battery pack as a battery of the present invention and a computer as an electronic device.

15 is a diagram showing an example of a relationship between an on / off state of a semiconductor switching element in FIG. 14 and a charging voltage of a battery cell.

FIG. 16 is an enlarged view showing a state of change of a charging voltage in FIG. 15;

FIG. 17 is a view showing another embodiment of the battery of the present invention and a connection example of a computer as an electronic device.

18 is a diagram showing an example of the voltage drop element in FIG.

FIG. 19 is a diagram illustrating voltage-time characteristics of a lithium ion secondary battery as an example of a secondary battery that is a battery cell.

[Explanation of symbols]

100: Computer (electronic device), 200:
Battery pack (battery), 201: case (container), 401: battery cell, 402: temperature sensor, 403: voltage controller, 404: controller of voltage controller, 405 ... · Semiconductor switching element, 503 ··· Voltage control unit, 504 ··· Controller, 505 ··· Voltage drop element, 506 ··· Changeover switch

Claims (5)

[Claims] 1. A secondary battery cell, a temperature sensor for measuring a temperature of the secondary battery cell or a temperature near the secondary battery cell, and controlling a charging voltage when charging the secondary battery cell. A battery comprising: a voltage control unit; a secondary battery cell, a temperature sensor, and a container accommodating the voltage control unit. According to a temperature detected by the temperature sensor, the voltage control unit controls a charging voltage of the secondary battery cell. Controlling the battery. 2. A voltage control unit comprising: a semiconductor switching element; and a controller for turning on / off the semiconductor switching element according to a temperature of the secondary battery cell to intermittently charge the secondary battery cell. The battery according to claim 1. 3. A voltage control unit, comprising: a voltage drop element arranged between a charging input terminal and a secondary battery cell to reduce a voltage; a charging input terminal, a voltage drop element, and a secondary battery cell. A changeover switch disposed between the input terminal for charging and a selector for selecting whether to connect the input terminal for charging directly to the secondary battery cell or to connect a voltage drop element between the input terminal for charging and the secondary battery cell; The battery according to claim 1, further comprising: a controller configured to perform an operation of switching the changeover switch according to a temperature of the secondary battery cell. 4. An electronic device having a main body and a display unit which is openable and closable on the main body, comprising a battery detachably set, the battery comprising: a secondary battery cell; A temperature sensor for measuring a temperature of the battery cell or a temperature near the secondary battery cell, a voltage control unit for controlling a charging voltage when charging the secondary battery cell, a secondary battery cell, a temperature sensor, And a container for accommodating the voltage control unit, wherein the voltage control unit controls the charging voltage of the secondary battery cell according to the temperature detected by the temperature sensor. 5. The electronic device having a battery according to claim 1, wherein the electronic device is a portable computer.