U.S. patent application number 11/668196 was filed with the patent office on 2008-09-04 for battery pack.
Invention is credited to Takayuki Inoi, Hiroshi Sasaki.
Application Number | 20080213633 11/668196 |
Document ID | / |
Family ID | 27785347 |
Filed Date | 2008-09-04 |
United States Patent
Application |
20080213633 |
Kind Code |
A1 |
Sasaki; Hiroshi ; et
al. |
September 4, 2008 |
BATTERY PACK
Abstract
A battery pack is provided which can be suitably used in a case
where charging of a dedicated secondary battery in a portable
terminal device is difficult. The battery pack is mounted in a
battery mounting section in a portable cellular phone (portable
terminal device) proper. In the battery pack, alkaline accumulators
are connected in series. Alkaline accumulators generate
electromotive forces having a voltage (3V) being lower than that of
the dedicated secondary battery. A power source circuit has a
boosting-type DC/DC converter which boosts a voltage of the
alkaline accumulators being connected in series at a level being
same as that of the dedicated secondary battery (for example,
4.5V), and outputs the boosted voltage. An electrical double layer
capacitor has a capacity to feed stable power to an internal
circuit in which power consumption increases or decreases in a
burst manner and is charged by application of an output of the
power source circuit and stores the power.
Inventors: |
Sasaki; Hiroshi; (Miyagi,
JP) ; Inoi; Takayuki; (Miyagi, JP) |
Correspondence
Address: |
WHITHAM, CURTIS & CHRISTOFFERSON & COOK, P.C.
11491 SUNSET HILLS ROAD, SUITE 340
RESTON
VA
20190
US
|
Family ID: |
27785347 |
Appl. No.: |
11/668196 |
Filed: |
January 29, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10387521 |
Mar 14, 2003 |
7183014 |
|
|
11668196 |
|
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Current U.S.
Class: |
429/7 |
Current CPC
Class: |
H01M 16/003 20130101;
H01M 6/42 20130101; H04M 1/0262 20130101; H01M 6/50 20130101; H01M
6/00 20130101; H02J 7/345 20130101; H01M 16/00 20130101; H01M 8/00
20130101; Y02E 60/50 20130101; H01M 6/5033 20130101 |
Class at
Publication: |
429/7 |
International
Class: |
H01M 12/08 20060101
H01M012/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 20, 2002 |
JP |
2002-079802 |
Claims
1.-14. (canceled)
15. A battery pack being placed in a portable terminal device in a
manner so as to be replaceable with a dedicated secondary battery
for being used as a power source of said portable terminal device
comprising: a fuel cell to generate a specified electromotive
force; and a package to house said fuel cell.
16. The battery pack according to claim 15, wherein said package,
instead of said dedicated secondary battery, is configured to be
placed in said portable terminal device and is provided with
terminals to feed said specified electromotive force of said fuel
cell to said portable terminal device.
17. The battery pack according to claim 15, further comprising: a
power storing unit to be charged by application of a voltage output
from said fuel cell, hereby storing fed power, and to feed the
stored power to said portable terminal device, wherein said a
package houses said fuel cell and said power storing unit.
18. The battery pack according to claim 17, wherein said power
storing unit is made up of an electrical double layer
capacitor.
19. The battery pack according to claim 17, further comprising; a
current limiting circuit to limit a current of input said specified
electromotive force of said fuel cell to a level being a
predetermined value or less, wherein said a package houses said
fuel cell, said power storing unit and said current limiting
circuit.
20. The battery pack according to claim 17, further comprising; a
voltage boosting unit to boost a voltage level of said specified
electromotive force fed from said fuel cell to a voltage level of
said dedicated secondary battery; and, wherein said power storing
unit is charged by application of a voltage output from said
voltage boosting unit, hereby storing fed power, and feed the
stored power to said portable terminal device, and wherein said a
package houses said fuel cell, said power storing unit and said
voltage boosting unit.
21. The battery pack according to claim 20, wherein said voltage
boosting unit comprises a Direct Current/Direct Current (DC/DC)
converter.
22. The battery pack according to claim 19, wherein said electrical
double layer capacitor has an equivalent serial resistance being
lower than that of said fuel cell.
23. The battery pack according to claim 18, wherein said electrical
double layer capacitor has a capacity being able to feed stable
power to said portable terminal device in which power consumption
increases or decreases in a burst manner.
24. The battery pack according to claim 15, wherein said portable
terminal device has a function of a Time Division Multiple Access
(TDMA)-type portable cellular phone.
25. A battery pack being placed in a portable terminal device in a
manner so as to be replaceable with a dedicated secondary battery
for being used as a power source of said portable terminal device
comprising: a fuel cell to generate electromotive force; a current
limiting circuit to limit a current of input electromotive force of
said fuel cell to a level being a predetermined value or less; and
a voltage boosting unit to boost a voltage of said electromotive
force of said fuel cell fed from said current limiting circuit to a
voltage level of said dedicated secondary battery and to feed
boosted voltage to said portable terminal device.
26. A battery pack being placed in a portable terminal device in a
manner so as to be replaceable with a dedicated secondary battery
for being used as a power source of said portable terminal device
comprising: a fuel cell to generate electromotive force; a current
limiting circuit to limit a current of input electromotive force of
said fuel cell to a level being a predetermined value or less; a
Direct Current/Direct Current (DC/DC) converter to boost a voltage
of said electromotive force of said fuel cell fed from said current
limiting circuit to a voltage level of said dedicated secondary
battery and to feed boosted voltage to said portable terminal
device; a package to house said fuel cell, said current limiting
unit, and said DC/DC converter; and wherein said package, instead
of said dedicated secondary battery, is configured to be placed in
said portable terminal device and is provided with terminals to
feed power output from said DC/DC converter to said portable
terminal device.
27. A battery pack being placed in a portable terminal device in a
manner so as to be replaceable with a dedicated secondary battery
for being used as a power source of said portable terminal device
comprising: a fuel cell to generate electromotive force; a current
limiting circuit to limit a current of input electromotive force of
said fuel cell to a level being a predetermined value or less; a
voltage boosting unit to boost a voltage of said electromotive
force of said fuel cell fed from said current limiting circuit to a
voltage level of said dedicated secondary battery; and a power
storing unit to be charged by application of a voltage output from
said voltage boosting unit, hereby storing fed power, and to feed
the stored power to said portable terminal device.
28. A battery pack being placed in a portable terminal device in a
manner so as to be replaceable with a dedicated secondary battery
for being used as a power source of said portable terminal device
comprising: a fuel cell to generate electromotive force; a current
limiting circuit to limit a current of input electromotive force of
said fuel cell to a level being a predetermined value or less; a
Direct Current/Direct Current (DC/DC) converter to boost said
voltage of said electromotive force of said fuel cell fed from said
current limiting circuit to a voltage level of said dedicated
secondary battery; a power storing unit to be charged by
application of a voltage output from said DC/DC converter and to
store fed power and to feed the stored power to said portable
terminal device; a package to house said fuel cell, said current
limiting circuit, said DC/DC converter, and said power storing
unit; and wherein said package, instead of said dedicated secondary
battery, is configured to be placed in said portable terminal
device and is provided with terminals to feed said power being
accumulated in said power storing unit to said portable terminal
device.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a battery pack and more
particularly to the battery pack that can be suitably used for a
portable terminal device such as a portable cellular phone being
carried by for example a user who is on the road over an extended
period of time.
[0003] The present application claims priority of Japanese Patent
Application No. 2002-079802 filed on Mar. 20, 2002, which is hereby
incorporated by reference.
[0004] 2. Description of the Related Art
[0005] Generally, a portable terminal device such as a portable
cellular phone 1 is so configured as to operate using its dedicated
secondary battery 20. For example, as shown in FIGS. 12A and 12B,
the portable cellular phone 1 is made up of a main body of portable
cellular phone 10 and the dedicated secondary battery 20. As shown
in FIGS. 12A and 12B, the main body of portable cellular phone 10
has a battery mounting section 11, a multifunctional connector 12,
terminals 13a and 13b, and an antenna 14. The dedicated secondary
battery 20 is mounted in the battery mounting section 11. To the
multifunctional connector 12 are connected a charging adapter used
to charge the dedicated secondary battery 20, a personal computer,
or a like. The terminals 13a and 13b are coupled to terminals 21a
and 21b (not shown) of the dedicated secondary battery 20 used to
take in electromotive force of the dedicated secondary battery 20.
The antenna 14 is adapted to transmit and receive radio waves to
and from a radio base station (not shown).
[0006] When the dedicated secondary battery 20 is discharged, if a
user stays indoors and commercial power supply is available, the
charging adapter is connected to the multifunctional connector 12
to charge the dedicated secondary battery 20. Moreover, when
commercial power supply is not available in such a case where a
user stays outdoors, conventionally, as shown in FIG. 13A, a
battery pack 30 is connected to the multi functional connector 12
to charge the dedicated secondary battery 20. The battery pack 30
serves as a simple charger or an emergency power source. The main
body of portable cellular phone 10, as shown in FIG. 13B, includes
a charge controlling circuit 40 and the internal circuit 50. The
charge controlling circuit 40 feeds electromotive force of the
battery pack 30 through terminals 13a and 13b and terminals 21a and
21b to the dedicated secondary battery 20 at a constant current and
at a constant voltage for charging. Power of the dedicated
secondary battery 20 is fed to an internal circuit 50 to perform
main operations of a TDMA (Time Division Multiple Access)-type
portable cellular phone.
[0007] FIGS. 14A, 14B, 14C, and 14D are circuit diagrams showing
electrical configurations of the battery pack 30 in FIGS. 13A and
13B. Each symbol of batteries shown in FIGS. 14A, 14B, 14C, and 14D
represents a cell unit of a battery and one cell has electromotive
force of 1.5V.
[0008] The battery pack 30 shown in FIG. 14A is made up of three
serially connected battery cells each having a voltage of 1.5 V
(for example, three pieces of alkaline accumulators) 31, 32, and
33. The battery pack 30 shown in FIG. 14B is made up of four
battery cells 31, 32, 33, and 34 (for example, four pieces of
alkaline accumulators, two pieces of serially-connected manganese
dioxide lithium batteries each having a voltage of 3.0 V, or a
like) each having a voltage of 1.5 V, a diode 35 for preventing
backflow of a current, and a resistor 36 for limiting currents,
being connected in series. The battery pack 30 shown in FIG. 14C is
made up of six serially-connected battery cells 31, 32, 33, 34, 37,
and 38 (for example, six pieces of alkaline accumulators, three
manganese dioxide lithium batteries each having a voltage of 3V,
one square-shaped stacked alkaline accumulator having a voltage of
9V, or a like) each having a voltage of 1.5 V, and a voltage
dropping circuit 39 adapted to drop a voltage of the battery cells
from 9V to 5V, all of which are connected in series. The battery
pack 30 shown in FIG. 14D is made up of three battery cells each
having a voltage that has come nearer to a final level and a
voltage boosting circuit 3A adapted to boost the voltage of the
battery cell up to a level of 5V, both being connected in
series.
[0009] FIG. 15 is a circuit diagram showing electrical
configurations of a charge controlling circuit 40 shown in FIGS.
13A and 13B. The charge controlling circuit 40 includes a current
limiting circuit 41, a voltage limiting circuit 42, a limiting-type
selecting switch 43, and a voltage detector 44. The current
limiting circuit 41 limits a current flow of power to be fed from
an AC adapter (adapter for charging) 60 adapted to convert a
voltage (AC100V) of commercial power supply to DC 6V or from the
battery pack 30 to a level that can be suitably used for charging
the dedicated secondary battery 20 and outputs it. The voltage
limiting circuit 42 limits a voltage of power to be fed from the AC
adapter 60 or from the battery pack 30 to a level (for example,
4.5V) that can be suitably used for charging the dedicated
secondary battery 20 and outputs it.
[0010] The limiting-type selecting switch 43 is used to select,
based on a selecting signal SL output from the voltage detector 44,
a power M of the current limiting circuit 41 and a power N of the
voltage limiting circuit 42 and outputs the selected power. The
voltage limiting circuit 42 outputs a voltage of a power Q output
from the limiting-type selecting switch 43 and detects it and,
based on a result from the selection, outputs the selecting signal
SL. In this case, if a voltage of the power Q is higher than that
being suitably used for charging the dedicated secondary battery
20, the power N of the voltage limiting circuit 42 is selected by
the selecting signal SL, and if the voltage of the power Q is lower
than that being suitably used for charging the dedicated secondary
battery 20, the power M of the current limiting circuit 41 is
selected by the selecting signal SL.
[0011] In the conventional portable cellular phone 1, when the
battery pack 30 is connected to the multifunctional connector 12,
the dedicated secondary battery 20 is charged at a constant current
and at a constant voltage fed from the battery pack 30 through the
charge controlling circuit 40, terminals 13a and 13b, and terminals
21a and 21b, and an electromotive force of the dedicated secondary
battery 20 is supplied to the internal circuit 50. Operations of
the TDMA-type portable cellular phone l are performed in the
internal circuit 50. Moreover, when the AC adapter 60, instead of
the battery cell 30, is connected to the multifunctional connector
12, the dedicated secondary battery 20 is charged at a constant
current and at a constant voltage fed from the AC adapter 60
through the charge controlling circuit 40, terminals 13a and 13b,
and terminals 21a and 21b.
[0012] However, the above conventional battery pack 30 has
following problems to be solved. That is, when a user goes the
outdoors carrying the portable cellular phone 1 and the dedicated
secondary battery 20 is already discharged and when commercial
power is not available because the user is outdoors, the user has
to perform charging the portable cellular phone 1 by using the
battery pack 30, however, in this case, it will be time before a
voltage of the portable cellular phone 1 reaches a specified level
according to a state of the dedicated secondary battery 20 and
therefore the portable cellular phone 1 does not operate
immediately even after the connection of the battery pack 30.
Another problem is that, since the dedicated secondary battery 20
makes up part of components of a power source section of the
portable cellular phone 1, if a failure occurs in the dedicated
secondary battery 20, the portable cellular phone 1 cannot be
operated even by the connection of the battery pack 30.
[0013] Moreover, there is still another problem that, since the
charge controlling circuit 40 is configured assuming that the
dedicated secondary battery 20 is charged, if the dedicated
secondary battery 20 is lost, the charge controlling circuit 40
does not operate normally in some cases and, as a result, a voltage
required to normally operate the portable cellular phone 1 cannot
be obtained even by the connection of the battery pack 30. Also,
still another problem is that, since a voltage required for
operating the charge controlling circuit 40 is 4V, it is necessary
for the battery pack 30 to have at least three battery cells (each
having a voltage of 1.5V) being connected in series, which thus
causes a user to feel that the portable cellular phone 1 is heavy
to carry. Furthermore, the conventional portable cellular phone
presents another problem in that, when the battery pack 30 is
connected to its multifunctional connector 12, other devices such
as personal computers or a like cannot be connected to the
multifunctional connector 12.
[0014] To solve these problems, a method is thought to be available
in which another dedicated secondary battery having a same function
as that of the dedicated secondary battery 20 and being in a
fully-charged state is carried as a backup cell. However, this
method has a problem in that that not only carrying the dedicated
secondary battery is attended with risk of occurrence of a short
but also buying such the backup dedicated secondary battery is
costly. Moreover, in this case, a user has to carry an AC adapter
required to charge such the dedicated backup secondary battery.
Also, since the portable cellular phone 1 is operated according to
the TDMA communication method, a judgement as to whether a voltage
of the dedicated secondary battery 20 has reached its final voltage
is made based on a voltage value that has dropped when power
consumption increases or decreases in a burst manner. As a result,
in some cases, a message that the voltage has reached its final
level even in a state where a discharging depth of the dedicated
secondary battery 20 is shallow (that is, battery capacity is still
residual somewhat) appears on a displaying section of the portable
cellular phone 1, which presents another problem that battery
capacity cannot be used to the fullest.
SUMMARY OF THE INVENTION
[0015] In view of the above, it is an object of the present
invention to provide a battery pack which is capable of operating a
portable cellular phone immediately even when a dedicated secondary
battery is discharged.
[0016] According to a first aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including: a primary battery to generate a
specified electromotive force; and a package to house the primary
battery.
[0017] In the foregoing first aspect, a preferable mode is one
wherein the package, instead of the dedicated secondary battery, is
configured to be placed in the portable terminal device and is
provided with terminals to feed the specified electromotive force
of the primary battery or the fuel cell to the portable terminal
device,
[0018] Also, a preferable mode is one that wherein further includes
a power storing unit to be charged by application of a voltage
output from the primary battery or the fuel cell, hereby storing
fed power, and to feed the stored power to the portable terminal
device,
[0019] wherein the a package houses the primary battery or the fuel
cell and the power storing unit.
[0020] Also, a preferable mode is one wherein the power storing
unit is made up of an electrical double layer capacitor.
[0021] Also, a preferable mode is one that wherein further includes
a current limiting circuit to limit a current of input the
specified electromotive force of the primary battery or the fuel
cell to a level being a predetermined value or less, wherein the a
package houses the primary battery or the fuel cell, the power
storing unit and the current limiting circuit.
[0022] Also, a preferable mode is one that wherein further includes
a voltage boosting unit to boost a voltage level of the specified
electromotive force fed from the primary battery or the fuel cell
to a voltage level of the dedicated secondary battery; and, wherein
the power storing unit is charged by application of a voltage
output from the voltage boosting unit, hereby storing fed power,
and feed the stored power to the portable terminal device, and
wherein the a package houses the primary battery or the fuel cell,
the power storing unit and the voltage boosting unit.
[0023] Also, a preferable mode is one wherein the voltage boosting
unit includes a Direct Current/Direct Current (DC/DC)
converter.
[0024] Also, a preferable mode is one wherein the electrical double
layer capacitor has an equivalent serial resistance being lower
than that of the primary battery or the fuel cell.
[0025] Also, a preferable mode is one wherein the electrical double
layer capacitor has a capacity being able to feed stable power to
the portable terminal device in which power consumption increases
or decreases in a burst manner.
[0026] According to a second aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including:
[0027] a primary battery to generate electromotive force;
[0028] a current limiting circuit to limit a current of input
electromotive force of the primary battery to a level being a
predetermined value or less; and
[0029] a voltage boosting unit to boost a voltage of the
electromotive force of the primary battery fed from the current
limiting circuit to a voltage level of the dedicated secondary
battery and to feed boosted voltage to the portable terminal
device.
[0030] According to a third aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including:
[0031] a primary battery to generate electromotive force;
[0032] a current limiting circuit to limit a current of input
electromotive force of the primary battery to a level being a
predetermined value or less;
[0033] a Direct Current/Direct Current (DC/DC) converter to boost a
voltage of the electromotive force of the primary battery fed from
the current limiting circuit to a voltage level of the dedicated
secondary battery and to feed boosted voltage to the portable
terminal device;
[0034] a package to house the primary battery, the current limiting
unit, and the DC/DC converter; and
[0035] wherein the package, instead of the dedicated secondary
battery, is configured to be placed in the portable terminal device
and is provided with terminals to feed power output from the DC/DC
converter to the portable terminal device.
[0036] According to a fourth aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including:
[0037] a primary battery to generate electromotive force;
[0038] a current limiting circuit to limit a current of input
electromotive force of the primary battery to a level being a
predetermined value or less;
[0039] a voltage boosting unit to boost a voltage of the
electromotive force of the primary battery fed from the current
limiting circuit to a voltage level of the dedicated secondary
battery; and
[0040] a power storing unit to be charged by application of a
voltage output from the voltage boosting unit, hereby storing fed
power, and to feed the stored power to the portable terminal
device.
[0041] According to a fifth aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including:
[0042] a primary battery to generate electromotive force;
[0043] a current limiting circuit to limit a current of input
electromotive force of the primary battery to a level being a
predetermined value or less;
[0044] a Direct Current/Direct Current (DC/DC) converter to boost
the voltage of the electromotive force of the primary battery fed
from the current limiting circuit to a voltage level of the
dedicated secondary battery;
[0045] a power storing unit to be charged by application of a
voltage output from the DC/DC converter and to store fed power and
to feed the stored power to the portable terminal device;
[0046] a package to house the primary battery, the current limiting
circuit, the DC/DC converter, and the power storing unit; and
[0047] wherein the package, instead of the dedicated secondary
battery, is configured to be placed in the portable terminal device
and is provided with terminals to feed the power being accumulated
in the power storing unit to the portable terminal device.
[0048] According to a sixth aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including: a fuel cell to generate a specified
electromotive force; and a package to house the fuel cell.
[0049] According to a seventh aspect of the present invention,
there is provided a battery pack being placed in a portable
terminal device in a manner so as to be replaceable with a
dedicated secondary battery for being used as a power source of the
portable terminal device including:
[0050] a fuel cell to generate electromotive force;
[0051] a current limiting circuit to limit a current of input
electromotive force of the fuel cell to a level being a
predetermined value or less; and
[0052] a voltage boosting unit to boost a voltage of the
electromotive force of the fuel cell fed from the current limiting
circuit to a voltage level of the dedicated secondary battery and
to feed boosted voltage to the portable terminal device.
[0053] According to an eighth aspect of the present invention,
there is provided a battery pack being placed in a portable
terminal device in a manner so as to be replaceable with a
dedicated secondary battery for being used as a power source of the
portable terminal device including:
[0054] a fuel cell to generate electromotive force;
[0055] a current limiting circuit to limit a current of input
electromotive force of the fuel cell to a level being a
predetermined value or less;
[0056] a Direct Current/Direct Current (DC/DC) converter to boost a
voltage of the electromotive force of the fuel cell fed from the
current limiting circuit to a voltage level of the dedicated
secondary battery and to feed boosted voltage to the portable
terminal device;
[0057] a package to house the fuel cell, the current limiting unit,
and the DC/DC converter; and
[0058] wherein the package, instead of the dedicated secondary
battery, is configured to be placed in the portable terminal device
and is provided with terminals to feed power output from the DC/DC
converter to the portable terminal device.
[0059] According to a ninth aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including:
[0060] a fuel cell to generate electromotive force;
[0061] a current limiting circuit to limit a current of input
electromotive force of the fuel cell to a level being a
predetermined value or less;
[0062] a voltage boosting unit to boost a voltage of the
electromotive force of the fuel cell fed from the current limiting
circuit to a voltage level of the dedicated secondary battery;
and
[0063] a power storing unit to be charged by application of a
voltage output from the voltage boosting unit, hereby storing fed
power, and to feed the stored power to the portable terminal
device.
[0064] According to a tenth aspect of the present invention, there
is provided a battery pack being placed in a portable terminal
device in a manner so as to be replaceable with a dedicated
secondary battery for being used as a power source of the portable
terminal device including:
[0065] a fuel cell to generate electromotive force;
[0066] a current limiting circuit to limit a current of input
electromotive force of the fuel cell to a level being a
predetermined value or less;
[0067] a Direct Current/Direct Current (DC/DC) converter to boost
the voltage of the electromotive force of the fuel cell fed from
the current limiting circuit to a voltage level of the dedicated
secondary battery;
[0068] a power storing unit to be charged by application of a
voltage output from the DC/DC converter and to store fed power and
to feed the stored power to the portable terminal device;
[0069] a package to house the fuel cell, the current limiting
circuit, the DC/DC converter, and the power storing unit; and
[0070] wherein the package, instead of the dedicated secondary
battery, is configured to be placed in the portable terminal device
and is provided with terminals to feed the power being accumulated
in the power storing unit to the portable terminal device.
[0071] With the above configurations, since a battery pack is
placed in a portable terminal device instead of a dedicated
secondary battery, power being stored in an electrical double layer
capacitor (power storing section) is supplied, immediately after
the battery pack is placed, to the portable terminal device, thus
enabling the portable terminal device to be immediately operated.
Moreover, even when the dedicated secondary battery is out of
running order or is lost, since the dedicated secondary battery
does not make up a power source section proper and the battery pack
is configured to be placed in the portable terminal device, the
portable cellular phone can be immediately operated. Since the
battery pack is provided with a voltage boosting unit (DC/DC
converter), the portable terminal device can be operated by using a
primary battery having a voltage being lower than that of the
dedicated secondary battery. Also, since the battery pack is not
connected to a multifunctional connector, other devices such as a
personal computer or a like can be connected to the multifunctional
connector. Furthermore, since almost no drop occurs in a voltage of
the electrical double layer capacitor (power storing section) even
while power consumption increases or decreases in a burst manner,
capacity of the primary battery can be utilized to the fullest.
[0072] Moreover, since the primary battery produces electromotive
force having a voltage being same as that of the dedicated
secondary battery and the power storing section is made up of the
electrical double layer capacitor having an equivalent serial
resistance being lower than that of the primary battery, a current
limiting circuit and DC/DC converter are not required, which can
simplify its configurations. Also, since the battery pack is
provided with a fuel cell, when fuel runs out, by supplementing the
fuel, operations of the battery pack can be immediately restored to
its normal state. Since the fuel cell generates electromotive force
having a same voltage as that of the dedicated secondary battery
and since the power storing section has an equivalent serial
resistance being lower than the fuel cell, the current limiting
circuit and DC/DC converters are not required, which can simplify
its configurations. Since almost no drop occurs in a voltage of the
electrical double layer capacitor (power storing section) even
while power consumption increases or decreases in a burst manner,
capacity of the fuel cell can be utilized to the fullest.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] The above and other objects, advantages, and features of the
present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings in
which:
[0074] FIGS. 1A and 1B are perspective views showing a battery pack
and a battery mounting section of a portable cellular phone
according to a first embodiment of the present invention;
[0075] FIGS. 2A, 2B, and 2C are diagrams illustrating the portable
cellular phone with its battery pack shown in FIG. 1A being placed
in a portable cellular phone proper according to the first
embodiment of the present invention;
[0076] FIG. 3 is a schematic block diagram showing electrical
configurations of a charge controlling circuit and a power source
circuit according to the first embodiment of the present
invention;
[0077] FIG. 4 is a schematic block diagram showing electrical
configurations of an internal circuit shown in FIG. 2C;
[0078] FIGS. 5A and 5B are perspective views showing a battery pack
and a battery mounting section of a portable cellular phone
according to a second embodiment of the present invention;
[0079] FIGS. 6A, 6B and 6C are diagrams illustrating the portable
cellular phone with its battery pack shown in FIG. 5A placed in a
portable cellular phone proper according to the second embodiment
of the present invention;
[0080] FIGS. 7A and 7B are perspective views showing a battery pack
and a battery mounting section of a portable cellular phone
according to a third embodiment of the present invention;
[0081] FIGS. 8A, 8B, and 8C are diagrams illustrating the portable
cellular phone in which its battery pack shown in FIG. 7A is placed
in a portable cellular phone proper according to the third
embodiment of the present invention;
[0082] FIG. 9 is a configuration diagram showing one example of a
fuel cell in FIG. 8C;
[0083] FIGS. 10A and 10B are perspective views showing a battery
pack and a battery mounting section of a portable cellular phone
according to a fourth embodiment of the present invention;
[0084] FIGS. 11A, 11B, and 11C are diagrams illustrating the
portable cellular phone in which its battery pack shown in FIG. 10A
is placed in a portable cellular phone proper according to the
fourth embodiment of the present invention;
[0085] FIGS. 12A and 12B are perspective views showing a dedicated
secondary battery and a battery mounting section of a conventional
portable cellular phone;
[0086] FIGS. 13A and 13B are diagrams showing the conventional
portable cellular phone in which a conventional battery pack is
connected to a multifunctional connector;
[0087] FIGS. 14A, 14B, 14C, and 14D are circuit diagrams showing
electrical configurations of the conventional battery pack in FIGS.
13A and 13B; and
[0088] FIG. 15 is a circuit diagram showing conventional electrical
configurations of a charge controlling circuit 40 shown in FIGS.
13A and 13B.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0089] Best modes of carrying out the present invention will be
described in further detail using various embodiments with
reference to the accompanying drawings.
First Embodiment
[0090] FIG. 1A is a perspective view showing a battery pack 70 and
FIG. 1B is a perspective view showing a battery mounting section 11
of a portable cellular phone proper 10 according to a first
embodiment of the present invention. A battery pack 70 of the first
embodiment, as shown in FIG. 1A is made up of alkaline accumulators
71 and 72, a power source circuit 73, an electrical double layer
capacitor 74, and a package 75 to house them, and is placed in a
portable cellular phone proper 10 instead of conventional
detachable dedicated secondary battery 20 as shown in FIG. 12A.
FIGS. 2A, 2B, and 2C are diagrams illustrating the portable
cellular phone with the battery pack 70 shown in FIG. 1A being
placed in the portable cellular phone proper 10 of the first
embodiment of the present invention. FIG. 2A is a front view of the
portable cellular phone proper 10 of FIG. 1A. FIG. 2B is a side
view of the portable cellular phone proper 10 and the battery pack
70 of FIGS. 1A and 1B. FIG. 2C is a circuit diagram showing
electrical configurations of the portable cellular phone of FIGS.
1A and 1B. In FIGS. 2A to 2C, same reference numbers are assigned
to components having same functions as those in FIG. 19. In the
portable cellular phone of the embodiment, as shown in FIG. 2A,
since the conventional battery pack 30 is not connected to a
multifunctional connector 12, and other devices such as a personal
computer or a like can be connected to the multifunctional
connector 12. As shown in FIG. 2B, the battery pack 70 is mounted
in the battery mounting section 11.
[0091] As shown in FIG. 2C, in the battery pack 70, the alkaline
accumulators 71 and 72 are connected in series. The alkaline
accumulators 71 and 72 being serially connected generate
electromotive force having a voltage (3V) being lower than that of
the conventional dedicated secondary battery 20. To a plus (+) side
terminal of the alkaline accumulator 71 is connected an input
terminal of the power source circuit 73. An electrical double layer
capacitor 74 is connected between an output terminal of the power
source circuit 73 and a minus (-) side terminal of the alkaline
accumulator 72. The power source circuit 73 has a boosting-type
DC/DC (Direct Current/Direct Current) converter which boosts a
voltage of the alkaline accumulators 71 and 72 being connected in
series, which is as high as that of the conventional dedicated
secondary battery 20 (for example, 4.5 V) and then outputs the
boosted voltage. The electrical double layer capacitor 74 is formed
to be thin and planar so that it is housed in the package 75,
having a capacity (for example, 10 mF or more) to feed stable power
to an internal circuit 50 in a portable cellular phone in which
power consumption increases or decreases in a burst manner and is
charged by application of a voltage output from the power source
circuit 73 and charged power is stored. Moreover, terminals 76a and
76b adapted to feed power accumulated in the electrical double
layer capacitor 74 to the portable cellular phone proper 10 are
connected to the electrical double layer capacitor 74.
[0092] FIG. 3 is a schematic block diagram showing electrical
configurations of a charge controlling circuit 40 and the power
source circuit 73 in FIG. 2C according to the first embodiment of
the present invention. In FIG. 3, same reference numbers are
assigned to components having same functions as those shown in FIG.
15. The power source circuit 73, as shown in FIG. 3, includes a
current limiting circuit 73a, a boosting-type DC/DC converter 73b
and a voltage detector 73c. The current limiting circuit 73a limits
a current flow of input electromotive force of the alkaline
accumulators 71 and 72 to a level being a predetermined value or
less and outputs the limited current. The above limited current
value is so set that a life of the alkaline accumulators 71 and 72
is lengthened as much as possible by discharging the electrical
double layer capacitor 74 preferentially rather than the alkaline
accumulators 71 and 72 while power consumption increases or
decreases in a burst manner. The boosting-type DC/DC converter 73b
boosts a voltage of electromotive force of the alkaline
accumulators 71 and 72 fed from the current limiting circuit 73a to
an output voltage being equal to that of the conventional dedicated
secondary battery 20. The voltage detector 73c detects a voltage U
output from the boosting-type DC/DC converter 73b and feeds the
detected voltage to the electrical double layer capacitor 74,
produces a negative feedback signal F, and transmits the produced
negative feedback signal F used to exert negative-feedback
controlling on the output voltage U to the boosting-type DC/DC
converter 73b.
[0093] FIG. 4 is a schematic block diagram showing electrical
configurations of the internal circuit 50 shown in FIG. 2C. The
internal circuit 50, as shown in FIG. 4, includes a power amplifier
51, a sending and receiving section 52, a control section 53, a
driver 54, a display 55, a microphone-speaker section 56, and a
regulator 57. The power amplifier 51 receives a voltage output from
the battery pack 70 and transmits a sending signal output from the
sending and receiving section 52 through an antenna 14 as a
transmitting radio wave to be handled according to a TDMA (Time
Division Multiple Access) communication method. To perform the TDMA
communication method, specifications called a PDC (Personal Digital
Cellular) system are employed in Japan and specifications called a
GSM (Global System for Mobile Communication) system are employed in
Europe. The sending and receiving section 52 transmits and receives
a radio signal through the antenna 14.
[0094] The control section 53 is made up of a CPU (Central
Processing Unit) or a like (not shown) and controls entire
operations of the internal circuit 50 based on a control program.
The driver 54 converts a voice signal fed from the
microphone-speaker section 56 into a digital signal, converts a
digital signal fed from the sending and receiving section 52 into a
voice signal, and sends out the converted signal to the
microphone-speaker section 56. Moreover, the driver 54 sends out a
signal for displaying to the display 55. The display 55 displays
information such as various messages to a user. The regulator 57
receives a voltage output from the battery pack 70, produces a
constant voltage having a predetermined value and feeds the
produced voltage to the sending and receiving section 52, control
section 53, driver 54, and microphone-speaker section 56.
[0095] Next, operations of the battery pack 70 of the first
embodiment are described. As shown in FIGS. 12A and 12B, a portable
cellular phone 1 operates using the dedicated secondary battery 20
as a power source and, if the dedicated secondary battery 20 is
discharged, instead of the dedicated secondary battery 20, the
battery pack 70 is used to supply power according to the present
invention. That is, in the battery pack 70, electromotive force
having a voltage of 3V is generated by alkaline accumulators 71 and
72 being connected in series. In the battery pack 70, a current
flow of the electromotive force produced by the alkaline
accumulators 71 and 72 is limited by the current limiting circuit
73a to a level being not more than a predetermined value and is
sent out to the boosting-type DC/DC converter 73b where a voltage
of the electromotive force is boosted to the output voltage U being
equal to such the voltage employed in the conventional dedicated
secondary battery 20. The output voltage U is detected by the
voltage detector 73c and is negative-feedback controlled so as to
be a predetermined value by transmission of the negative feedback
signal F from the voltage detector 73c to the boosting-type DC/DC
converter 73b. Moreover, the output voltage U of the boosting-type
DC/DC converter 73b is applied to the electrical double layer
capacitor 74. Then, power is stored in the electrical double layer
capacitor 74. The power is fed through terminals 76a and 76b (FIG.
3) from terminals 13a and 13b (FIG. 3) to the portable cellular
phone proper 10. In the portable cellular phone proper 10, a
transmitting radio wave is transmitted according to the TDMA
communication method and, at this point, a pulse-like load current
having a frequency determined according to the TDMA communication
method is taken out from the battery pack 70. Since the electrical
double layer capacitor 74 has capacitance enough to feed stable
power to the internal circuit 50 in which power consumption
increases or decreases in a burst manner, almost no drop in a
voltage of the electrical double layer capacitor 74 occurs even
while power consumption of the power amplifier 51 increases or
decreases in a burst manner. Therefore, since a message that a
voltage of the battery pack 70 has reached a final voltage even in
a state in which a discharging depth of the alkaline accumulators
71 and 72 is shallow does not appear on the display 55 of the
portable cellular phone proper 10, capacity of the alkaline
accumulators 71 and 72 can be utilized to the fullest.
[0096] Thus, according to configurations of the first embodiment,
since the battery pack 70 is placed in the portable cellular phone
proper 10 instead of the dedicated secondary battery 20, power
being accumulated in the electrical double layer capacitor 74 is
fed to the portable cellular phone immediately after the battery
pack 70 is installed, thereby enabling the portable cellular phone
to be operated immediately. Moreover, even when the dedicated
secondary battery 20 is out of running order or is lost, the
portable cellular phone can be operated immediately, since the
dedicated secondary battery 20 does not make up a power source
section proper and the battery pack 70 is mounted in the battery
mounting section 11 instead. Also, the battery pack 70, since it is
provided with the boosting-type DC/DC converter 73b, can operate
the portable cellular phone by serially-connected and light-weight
two pieces of alkaline accumulators 71 and 72 or one piece of
alkaline accumulator. Furthermore, since the battery pack 70 is
connected to terminals 13a and 13b and is not connected to the
multifunctional connector 12, the multifunctional connector 12 can
be connected to other devices such as a personal computer or a
like. Also, since a voltage of the electrical double layer
capacitor 74 does not drop even when the power consumption
increases or decreases in a burst manner, capacity of the alkaline
accumulators 71 and 72 can be utilized to the fullest. Also, since
the user of the portable cellular phone can easily obtain such
alkaline accumulators regardless of where or when the user lives or
stays, when the alkaline accumulators 71 and 72 are discharged, the
user can replace the discharged alkaline accumulators 71 and 72
with new ones.
Second Embodiment
[0097] FIGS. 5A and 5B are perspective views showing a battery pack
70A and a battery mounting section 11 of a portable cellular phone
proper 10 according to a second embodiment of the present
invention. In FIGS. 5A and 5B, same reference numbers are assigned
to components having same functions as those in FIGS. 1A and 1B. In
the battery pack 70A of the second embodiment, as shown in FIG. 5A,
a power source circuit 73 is removed from the battery pack 70A and
an alkaline accumulator 77 is additionally provided. Other
components are same as those in FIGS. 1A and 1B and their
description is omitted for brevity.
[0098] FIGS. 6A, 6B and 6C are diagrams illustrating a portable
cellular phone in which its battery pack 70A shown in FIG. 5A is
placed in a portable cellular phone proper 10 (FIG. 5B) of the
second embodiment of the present invention. In FIGS. 6A, 6B, and
6C, same reference numbers are assigned to components having same
functions as those in FIGS. 2A, 2B, and 2C. As shown in FIG. 6C, in
the battery pack 70A, alkaline accumulators 71, 72, and 77 are
connected in series. The serially connected alkaline accumulators
71, 72, and 77 generate electromotive force having a voltage of 4.5
V, which is same as that generated by a dedicated secondary battery
20 provided in the conventional example. To the serially connected
alkaline accumulators 71, 72, and 77 is connected an electrical
double layer capacitor 74 in parallel. In the second embodiment,
the electrical double layer capacitor 74 whose equivalent serial
resistance is lower than that of the serially connected alkaline
accumulators 71, 72, and 77 is used. The equivalent serial
resistance is so set that a life of each of the alkaline
accumulators 71, 72, and 77 is lengthened as much as possible by
discharging the electrical double layer capacitor 74 preferentially
rather than each of the alkaline accumulators 71, 72, and 77 while
power consumption increases or decreases in a burst manner.
[0099] Next, operations of the battery pack 70A of the second
embodiment are described. The conventional portable cellular phone
1 operates using the dedicated secondary battery 20 shown in FIG.
12A as a power source. However, in the embodiment, at this point,
if the dedicated secondary battery 20 of the portable cellular
phone 1 is discharged, the battery pack 70A instead of the
dedicated secondary battery 20 is used to supply power. That is, in
the battery pack 70A, electromotive force of 4.5V is generated by
the serially connected alkaline accumulators 71 and 72. A voltage
produced by the alkaline accumulators 71, 72, and 77 is applied to
an electrical double layer capacitor 74. Then, the produced power
is stored in the electrical double layer capacitor 74. The produced
power is supplied through terminals 76a and 76b from terminals 13a
and 13b to the portable cellular phone proper 10. In the portable
cellular phone proper 10, same operations as in the first
embodiment are performed. In this case, since the equivalent serial
resistance of the electrical double layer capacitor 74 is lower
than that of the serially connected alkaline accumulators 71, 72,
and 77, the electrical double layer capacitor 74 is preferentially
discharged while power consumption increases or decreases in a
burst manner. Since almost no drop in a voltage of the electrical
double layer capacitor 74 occurs even while power consumption
increases or decreases in a burst manner, a message that a voltage
of the battery pack 70A has reached a final voltage even in a state
in which a discharging depth of the alkaline accumulators 71, 72,
and 77 is shallow does not appear on a display section of the
portable cellular phone proper 10, capacity of the alkaline
accumulators 71, 72, and 77 can be utilized to the fullest.
[0100] Thus, according to configurations of the second embodiment,
since the battery pack 70A is placed in the portable cellular phone
proper 10 instead of the dedicated secondary battery 20, power
being accumulated in the electrical double layer capacitor 74 is
fed to the portable cellular phone proper immediately after the
battery pack 70A is installed, thereby enabling the portable
cellular phone to be operated immediately. Since the battery pack
70A is mounted in the portable cellular phone proper 10 and since
the dedicated secondary battery 20 is not mounted in a power source
section, the portable cellular phone can be operated immediately
even if the dedicated secondary battery 20 is out of running order
or is lost. Moreover, in the battery pack 70A, since the alkaline
accumulators 71, 72, and 77 produce electromotive force having same
voltage (for example, 4.5V) as that of the dedicated secondary
battery 20 and since the equivalent serial resistance of the
electrical double layer capacitor 74 is lower than that of the
alkaline accumulators 71, 72, and 77, mounting of a power source
circuit 73 (as in the first embodiment) is not required and its
configurations can be more simplified. Moreover, since the battery
pack 70A is connected to terminals 13a and 13b and is not connected
to a multifunctional connector 12, the multifunctional connector 12
can be connected to other devices such as a personal computer or a
like. Also, since a voltage of the electrical double layer
capacitor 74 does not drop even when the power consumption
increases or decreases in a burst manner, capacity of the alkaline
accumulators 71, 72, and 77 can be utilized to the fullest.
Third Embodiment
[0101] FIGS. 7A and 7B are perspective views showing a battery pack
70B and a battery mounting section 11 of a portable cellular phone
proper 10 according to a third embodiment of the present invention.
In FIGS. 7A and 7B, same reference numbers are assigned to
components having same functions as those in FIGS. 1A and 1B and
description of some parts have been omitted. In the battery pack
70B of the third embodiment, as shown in FIGS. 7A and 7B, instead
of alkaline accumulators 71 and 72 shown in FIGS. 1A and 1B, a fuel
cell 78 is provided. Other configurations are same as those in
FIGS. 1A and 1B.
[0102] FIGS. 8A, 8B, and 8C are diagrams illustrating a portable
cellular phone in which its battery pack 70B shown in FIG. 7A is
placed in the portable cellular phone proper 10 of the first
embodiment of the present invention. In FIGS. 8A, 8B, and 8C, same
reference numbers are assigned to components having same functions
as those in FIG. 2. As shown in FIG. 8C, in the battery pack 70B,
the fuel cell 78 is provided instead of the serially connected
alkaline accumulators 71 and 72. The fuel cell 78 produces
electromotive force having a voltage (for example, 3V) being lower
than that of the dedicated secondary battery 20 (conventional art).
Other configurations are same as those in FIG. 2.
[0103] FIG. 9 is a configuration diagram showing one example of the
fuel cell 78 in FIG. 8C. The fuel cell 78, as shown in FIG. 9,
includes a positive polarity side gas chamber 79, a positive
polarity 7A, a negative polarity side gas chamber 7B, a negative
polarity 7C, an electrolyte layer 7D placed between the positive
polarity 7A and the negative polarity 7C. In the fuel cell 78, a
positive polarity active material (oxidizing agent) is taken in the
positive polarity side gas chamber 79 and a given negative active
material (fuel made of hydrogen, methanol, or a like) is taken in
the negative polarity side gas chamber 7B and a reaction product is
output from the positive polarity active material 79, the negative
polarity side gas chamber 7B, and the electrolyte layer 7D and, at
a same time, electromotive force "e" is produced between the
positive polarity 7A and the negative polarity 7C.
[0104] Next, operations of the battery cell of the third embodiment
are described. A portable cellular phone 1 shown in FIGS. 12A and
12B is operated using a dedicated secondary battery 20 as a power
source in the conventional art. However, in the embodiment, if the
dedicated secondary battery 20 in the portable cellular phone 1 is
discharged, instead of the dedicated secondary battery 20, the
battery pack 70B is used to supply power. That is, in the battery
pack 70B of the embodiment, electromotive force having a voltage of
3V is generated by the fuel cell 78. A current flow of the
electromotive force is limited by a current limiting circuit 73a to
a level being not more than a predetermined value and is sent out
to a boosting-type DC/DC converter 73b and then is boosted by the
boosting-type DC/DC converter 73b to an output voltage "U" (FIG. 3)
being same as that of the dedicated secondary battery 20. The
output voltage U is detected by a voltage detector 73c and is
negative-feedback controlled so as to be a predetermined value by
transmission of a negative feedback signal F from the voltage
detector 73c to the boosting-type DC/DC converter 73b. The output
voltage U from the boosting-type DC/DC converter 73b is applied to
a electrical double layer capacitor 74 (FIG. 7A). The applied power
is stored in the electrical double layer capacitor 74. The power is
fed through terminals 76a and 76b from terminals 13a and 13b to the
portable cellular phone proper 10. In the portable cellular phone
proper 10, same operations as those in the first embodiment are
performed are performed. In this case, since the electrical double
layer capacitor 74 has a capacitor to feed stable power to an
internal circuit 50 in which power consumption increases or
decreases in a burst manner, almost no drop in a voltage of the
electrical double layer capacitor 74 occurs even while power
consumption of a power amplifier 51 increases or decreases in a
burst manner. Therefore, since a message that a voltage of the
battery pack 70B has reached a final level even in a state in which
a discharging depth of the fuel cell 78 is shallow does not appear
on a display section of the portable cellular phone proper 10,
capacity of the fuel cell 78 can be utilized to the fullest.
[0105] Thus, in the third embodiment, almost same advantages as
obtained in the first embodiment can be also achieved.
Additionally, since the battery pack 70B is provided with the fuel
cell 78 instead of the alkaline accumulators 71 and 72 shown in
FIGS. 1A and 1B, when fuel runs out, by supplementing the fuel,
operations of the battery pack 70B are immediately restored to its
normal state. Moreover, since no drop in voltage of the electrical
double layer capacitor 74 occurs even while power consumption
increases or decreases in a burst manner, capacity of the fuel cell
78 can be utilized to the fullest.
Fourth Embodiment
[0106] FIGS. 10A and 10B are perspective views showing a battery
pack 70C and a battery mounting section 11 of a portable cellular
phone proper 10 according to a fourth embodiment of the present
invention. In FIGS. 10A and 10B, same reference numbers are
assigned to components having same functions as those in FIGS. 7A
and 7B. In the battery pack 70C, as shown in FIG. 10A, a power
source circuit 73 provided in a battery pack 70B shown in FIG. 7A
is removed and, instead of a fuel cell 78, a fuel cell 78C is
provided. Other configurations are same as those in FIGS. 7A and 7B
and description has been omitted.
[0107] FIGS. 11A, 11B, and 11C are diagrams illustrating a portable
cellular phone in which the battery pack 70C shown in FIG. 10A is
placed in a portable cellular phone proper 10 of the fourth
embodiment. In FIG. 11A, 11B, and 11C, same reference numbers are
assigned to components having same functions as those in FIGS. 8A,
8B, and 8C. As shown in FIG. 11C, in the battery pack 70C, instead
of the fuel cell 78 shown in FIGS. 8C, a fuel cell 78C that can
produce electromotive force being different from that in the fuel
cell 78 is provided. The fuel cell 78C produces electromotive force
having a voltage (for example, 4.5V) being same as that of a
dedicated secondary battery 20 employed in the conventional case.
To the fuel cell 78C is connected an electrical double layer
capacitor 74 in parallel. In the embodiment, the electrical double
layer capacitor 74 whose equivalent serial resistance is lower than
that of the fuel cell 78C is used. The equivalent serial resistance
is so set that use time of the fuel cell 78C is lengthened as much
as possible by discharging the electrical double layer capacitor 74
preferentially rather than the fuel cell 78C while power
consumption increases or decreases in a burst manner.
[0108] Next, operations of the battery pack 70C of the embodiment
are described. A portable cellular phone 1 shown in FIGS. 12A and
12B is operated using the dedicated secondary battery 20 as a power
source. However, in the fourth embodiment, if the dedicated
secondary battery 20 of the portable cellular phone 1 is
discharged, the battery pack 70C instead of the dedicated secondary
battery 20 is used to supply power. That is, in the battery pack
70C, electromotive force having a voltage of 4.5V is produced by
the fuel cell 78C. A voltage of the fuel cell 78C is applied to the
electric double layer capacitor 74. Then, power is accumulated in
the electrical double layer capacitor 74. The power is fed through
terminals 76a and 76b from terminals 13a and 13b to the portable
cellular phone proper 10. In the portable cellular phone proper 10,
same operations as those in the first embodiment are performed. In
this case, since an equivalent serial resistance of the electrical
double layer capacitor 74 is lower than that of the fuel cell 78C,
while power consumption increases or decreases in a burst manner,
the electrical double layer capacitor 74 is preferentially
discharged. Moreover, since almost no drop in a voltage of the
electrical double layer capacitor 74 occurs even while power
consumption increases or decreases in a burst manner, a message
that a voltage of the fuel cell 78C has reached a final voltage
even in a state in which a discharging depth of the fuel cell 78C
is shallow does not appear on a display section of the portable
cellular phone proper 10, capacity of the fuel cell 78C can be
utilized to the fullest.
[0109] Thus, in the fourth embodiment, almost the same advantages
as obtained in the second embodiment can be achieved. Additionally,
since the battery pack 70C is provided with the fuel cell 78C,
instead of alkaline accumulators 71, 72, and 77 employed in the
conventional case shown in FIG. 6C, even when the fuel runs out, by
supplementing the fuel, operations of the portable cellular phone
can be immediately restored to its normal state. Moreover, since
almost no drop in a voltage of the electrical double layer
capacitor 74 occurs even while power consumption increases or
decreases in a burst manner, capacity of the fuel cell 78 can be
utilized to the fullest.
[0110] It is apparent that the present invention is not limited to
the above embodiments but may be changed and modified without
departing from the scope and spirit of the invention. For example,
in each of the above embodiments, when a dedicated secondary
battery 20 is discharged, battery packs 70, 70A, 70B, and 70C are
placed instead of the dedicated secondary battery 20, however, the
battery packs 70, 70A, 70B, and 70C may be mounted without using
the dedicated secondary battery 20 from a first stage. Moreover,
the two pieces of alkaline accumulators 71 and 72 maybe one
accumulator. However, in this case, a boosting-type DC/DC converter
73b must be so configured that a voltage of electromotive force of
one alkaline accumulator is boosted to an output voltage U being
same as a voltage of the dedicated secondary battery 20. Moreover,
each of the alkaline accumulators may be, for example, manganese
dioxide lithium cell, nickel hydrogen cell, or a like. Also, the
electrical double layer capacitor 74 may be, for example, an
aluminum electrolytic capacitor or a like. Also, in each of the
above embodiments, battery cells 70, 70A, 70B, and 70C are placed
in the portable cellular phone proper 10, however, may be placed
not only in the portable cellular phone but also in a PDA (Personal
Digital Assistance) containing functions of a portable cellular
phone.
* * * * *