U.S. patent application number 09/777860 was filed with the patent office on 2001-08-09 for battery pack.
This patent application is currently assigned to NEC Mobile Energy Corporation. Invention is credited to Sonobe, Satoshi.
Application Number | 20010011883 09/777860 |
Document ID | / |
Family ID | 18553891 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010011883 |
Kind Code |
A1 |
Sonobe, Satoshi |
August 9, 2001 |
Battery pack
Abstract
The present invention provides a battery pack, using a battery 1
comprising one or more cells as a power source and for connecting
power to an external host device, and it comprises
charging/discharging means 2-4 connected in series to the battery 1
and for performing charging and discharging, current detecting
means 6 and 7 for detecting charging and discharging current,
voltage detecting means 5 for detecting voltage, temperature
detecting means for detecting temperature, and control means 9,
whereby the control means is operated in such manner that it turns
the state from at least one of charging state, discharging state,
charging stop state, and discharging stop state to another state by
controlling the charging/discharging means 2-4 based on the
charging/discharging current, the voltage and the temperature as
detected, and said state information is transmitted to the external
host device when there is a request or at regular interval or when
there is state transition, and state transition such as a
charging/discharging state or a stop state of the battery pack
controlled according to charging/discharging current, voltage, and
temperature is controlled, and information of state transition can
be managed and controlled by the external host device.
Inventors: |
Sonobe, Satoshi;
(Utsunomiya-shi, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
NEC Mobile Energy
Corporation
Utsunomiya-shi
JP
|
Family ID: |
18553891 |
Appl. No.: |
09/777860 |
Filed: |
February 7, 2001 |
Current U.S.
Class: |
320/134 |
Current CPC
Class: |
H02J 7/00304 20200101;
H02J 7/00714 20200101; H02J 7/0029 20130101; H02J 7/007182
20200101; H02J 7/0047 20130101; H02J 7/0049 20200101; H02J 7/00309
20200101 |
Class at
Publication: |
320/134 |
International
Class: |
H02J 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2000 |
JP |
2000-028496 |
Claims
What is claimed is:
1. A battery pack, using a battery comprising one or more cells as
a power source and for connecting power to an external host device,
said battery pack comprising: charging/discharging means connected
in series to said battery and used for discharging and discharging;
current detecting means for detecting the charging/discharging
current; voltage detecting means for detecting voltage; and
temperature detecting means for detecting temperature, whereby: at
least charging state, discharging state, charging stop state and
discharging stop state can be selected by controlling said
charging/discharging means based on the charging/discharging
current, the voltage, and the temperature as detected, and it is
turned from one of these states to another state, and state
transition information is transmitted to the external host
device.
2. A battery pack according to claim 1, wherein said
charging/discharging means comprises a charging switch for charging
said battery and a discharging switch for discharging said battery,
said control means is operated in such manner that it is turned to
the charging state or the discharging state when said charging
switch and said discharging switch are both turned on and charging
current or discharging current higher than a preset values is
detected, it is turned to a charging stop state when the charging
switch is turned off and the discharging switch is turned on, and
it is turned to a discharge stop state when the charging switch is
turned on and the discharging switch is turned off.
3. A battery pack according to claim 2, wherein said control means
is operated in such manner that it is turned to system
disconnection when it has been detected that connection with the
external host device is disconnected, and the charging switch and
the discharging switch are both turned off at the system
disconnection, and this state is turned to a non-operation
state.
4. A battery pack according to claim 2, wherein said
charging/discharging means comprises a spare charging switch
arranged in parallel to the charging switch and the discharging
switch and used for charging with micro current, said control means
is operated in such manner that the charging switch and the
discharging switch are both turned off and only the spare charging
switch is turned on when voltage is lower than a preset value, and
it is turned to spare charging state.
5. A battery pack according to claim 4, wherein the control means
is operated in such manner that the spare charging switch is turned
off when the preset voltage value is not reached even when charging
has been performed for a preset period of time with the preset
amount of charging current in said spare charging state, and it is
turned to a spare charging state.
6. A battery pack according to claim 4, wherein said control means
is operated in such manner that, in the spare charging state, it is
turned to the non-operation state under the condition that the cell
voltage is higher than the preset value and system disconnection
has been detected.
7. A battery pack according to claim 1, wherein said control means
is operated in such manner that, when the voltage is compared with
the preset value and pulse charging is performed, it is turned to a
charging stop state when the average current during a preset period
of time is lower than a preset value, and it is turned to a spare
stop state based on full charging detection.
8. A battery pack according to claim 2, wherein said control means
is operated in such manner that, when the voltage is compared with
the preset value and pulse charging is performed, and when the
charging temporary stop state where the charging switch is turned
off and the discharging switch is turned on is longer than the
preset period of time, it is turned to the charging stop state, and
it is defined as a charging stop state based on full charging
detection.
9. A battery pack according to claim 7 or 8, wherein the control
means is operated in such manner that, in the charging stop state
based on the full charging detection, it is turned to the charging
state under the condition that the charging ratio is lower than the
preset value.
10. A battery pack according to claim 1, wherein said control means
is operated in such manner that it is turned to charging stop state
under the condition that the charging current is higher than the
preset value, and this state is defined as a charging stop state
based on abnormal current.
11. A battery pack according to claim 1, wherein said control means
is operated in such manner that, in the charging state, it is
turned to the charging stop state under the condition that the cell
voltage is lower than the preset value even when the charging time
is longer than the preset period of time, and this state is defined
as a charging stop state based on abnormal charging time.
12. A battery pack according to one of claims 7, 8, 10 or 11,
wherein said control means is operated in such manner that, in the
charging stop state based on the full charging detection, in the
charge stop state based on abnormal current, and in the charging
stop state based on abnormal charging time, it is turned to the
discharging state under the condition that the discharging has been
detected, and it is turned to the non-operation state under the
condition that system disconnection has been detected.
13. A battery pack according to claim 1, wherein the control means
is operated in such manner that, in the charging state, it is
turned to the charging stop state under the condition that the cell
temperature is higher than the preset value, and this state is
defined as a charging stop state based on temperature.
14. A battery pack according to claim 13, wherein the control means
is operated in such manner that it is turned from the charging stop
state based on the temperature to the charging state under the
condition that the cell temperature is lower than the preset
value.
15. A battery pack according to claim 1, wherein the control means
is operated in such manner that, in the charging state, it is
turned to the discharging stop state under the condition that the
cell temperature is higher than the preset value, and this state is
defined as a discharging stop state based on abnormal
temperature.
16. A battery pack according to claim 1, wherein the control means
is operated in such manner that, in the discharging state, it is
turned to the discharging stop state under the condition that the
discharging current is higher than the preset value, and this state
is defined as a discharging stop state based on abnormal
current.
17. A battery pack according to claim 1, wherein said control means
is operated in such manner that said state transition information
is transmitted to the external host device at least once when there
is a request or at regular interval or when there is state
transition.
18. A battery pack according to claim 1, wherein the control means
counts the time elapsed since it has been turned to the current
state and this count value is transmitted to the external host
device.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a battery pack, using a
battery comprising one or more cells as a power source and for
connecting power to an external host device.
[0002] A battery pack comprises one or more cells (secondary
batteries) of charging type, and it is used as a power source for
an electronic device such as portable telephone, notebook-sized
personal computer, CD or DVD player, digital camera, etc. In an
external host device such as portable electronic device using a
battery pack of this type as the power source, it is essential to
facilitate the control and the management to identify the condition
of the battery pack. In case of a trouble, it is necessary to
promptly judge how to restore the condition to the normal. However,
in a battery pack of conventional type, it has been not possible to
fulfill these functions.
SUMMARY OF THE INVENTION
[0003] To solve the above problems, it is an object of the present
invention to provide a battery pack, by which it is possible to
control state transition such as a charging/discharging state or a
stop state and to monitor information on state transition of the
battery pack at the external host device.
[0004] To attain the above object, the present invention provides a
battery pack, using a battery comprising one or more cell as a
power source and for connecting power to an external host device,
and said battery pack comprises charging/discharging means
connected in series to the battery and for performing charging and
discharging, current detecting means for detecting the charging and
the discharging current, voltage detecting means for detecting
voltage, temperature detecting means for detecting temperature, and
control means, whereby the control means is operated in such manner
that it is turned from at least one of charging state, discharging
state, charging stop state or discharging stop state to another
state by controlling the charging/discharging means according to
the charging/discharging current, voltage and temperature as
detected, and information of said state transition is transmitted
to the external host device at least once when there is a request
or at regular interval or when there is state transition.
[0005] Further, the charging/discharging means comprises a switch
for charging the battery and a switch for discharging the battery.
The control means comprises a switch for spare charging, whereby,
in charging state or discharging state, the switch for charging and
the switch for discharging are both turned on. In the charging stop
state, the switch for charging is turned off and the switch for
discharging is turned on. In the discharge stop state, the switch
for charging is turned on and the switch for discharging is turned
off, and it comprises a spare charging switch arranged in parallel
to the charging switch and the discharging switch and for charging
micro current or very small amount of current. The control means is
operated in such manner that, when the voltage is lower than the
preset value, the charging switch and the discharging switch are
turned off and only the spare charging switch is turned on, and it
is turned to a spare charging state. When the voltage is not higher
than the preset voltage value even when charging has been performed
with the preset charging current under the spare charging state,
the control means turns off the spare charging switch and it is
turned to a spare charging stop state. When it has been detected
that the connection with the external host device is disconnected,
it is turned to system disconnection. The charging switch and the
discharging switch are both turned off, and it is turned to a
non-operation state.
[0006] Also, the control means is operated in such manner that,
when the voltage is compared with the preset value and pulse
charging is performed, and when average current in the preset
period of time is lower than the preset value, it is turned to a
charging stop state and it is defined as a charging stop state
based on full charging detection. Also, when the charging switch is
turned off and the discharging switch is turned on in the charging
temporary stop state, and when this charging temporary state is
longer than the preset period of time, it is turned to the charging
stop state, and this is defined as a charging stop state based on
full charging detection. In the charging stop state based on the
full charging detection, it is turned to the charging state under
the condition that the charging ratio is lower than the preset
value. In the charging state, it is turned to the charging stop
state under the condition that the charging current is higher than
the preset value, and this sate is defined as a charging stop state
based on abnormal current. Also, it is turned to the charging stop
state under the condition that the cell voltage is lower than the
preset value even when the charging time is longer than the preset
time, and this state is defined as a charging stop state based on
abnormal charging time. Also, in the charging stop state based on
the full charging detection, in the charging stop state based on
abnormal current, and in the charging stop state based on abnormal
charging time, it is turned to discharging state under the
condition that discharging has been detected, and it is turned to
the non-operation state under the condition that system
disconnection has been detected.
[0007] Also, the control means is operated is such manner that, in
the charging state, it is turned to a charging stop state under the
condition that the cell temperature is higher than the preset
value, and this state is defined as a charging stop state based on
temperature. Also, under the condition that the cell temperature is
lower than the preset value, it is turned from the charging stop
state based on the temperature to the charging state. In the spare
charging state, it is turned to a non-operation state under the
condition that the cell voltage is higher than the preset value and
system disconnection has been detected. In the discharging state,
it is turned to the discharging stop state under the condition that
the cell temperature is higher than the preset value, and this
state is defined as a discharging stop state based on abnormal
temperature. In the discharging state, it is turned to discharging
stop state under the condition that the discharging current is
higher than the preset value, and this state is defined as a
discharging stop state based on abnormal current.
[0008] Still other objects and advantages of the invention will in
part be obvious and will in part be apparent from the
specification.
[0009] The invention accordingly comprises the features of
construction, combination of elements, and arrangement of parts
which will be exemplified in the construction hereinafter set
forth, and the scope of the invention will be indicated in the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a block diagram showing an embodiment of a battery
pack according to the present invention;
[0011] FIG. 2 is a table of judgment flags, showing the results of
judgment under various conditions of state transition control;
[0012] FIG. 3 is a table of an arrangement example of state flags
to maintain the state under transition control;
[0013] FIG. 4 is a flow chart to explain an example of processing
to perform state transition control; and
[0014] FIG. 5 is a block diagram of an example of state
transition.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Description will be given below on an embodiment of the
present invention referring to the attached drawings. FIG. 1 shows
an embodiment of a battery pack according to the present invention.
Reference numeral 1 denotes a battery, 2 a charging FET, 3 a
discharging FET, 4 a spare charging FET, 5 a voltage detection IC,
6 a current detection resistance, 7 an operational amplifier, 8 a
display unit, 9 a microcomputer, and 10 an EEPROM.
[0016] In FIG. 1, the battery 1 comprises one or more cells. The
charging FET 2 is a switching element for charging the battery 1,
and the discharging FET 3 is a switching element for discharging
the battery 1. The spare charging FET 4 is arranged in parallel to
the charging FET 2 and the discharging FET 3 and it is a switching
element for charging the battery 1 with micro current or very small
amount of current. The voltage detection IC 5 is to detect battery
voltage or cell voltage Vb. The current detection resistance 6 and
the operational amplifier 7 are to detect a charging current Ic and
a discharging current Id respectively. The microcomputer 9 is a
computer for control, which compares various values with preset
values and makes judgment. These values to be compared with the
preset values include the battery voltage or the cell voltage Vb
detected at the voltage detection IC 5, the charging current Ic or
the discharging current Id detected at the current detection
resistance 6 and the operational amplifier 7, and a cell
temperature Hb detected by means such as a temperature sensor (not
shown) It also judges connecting condition with an external host
equipment or device (i.e. the system is disconnected or not) and
controls state transition of the battery pack by performing on-off
control of the spare charging FET 4. In the state transition
control, transition operation is performed from the following four
types of state to another state: a charging state "a" where the
charging FET 2 and the discharging FET 3 are turned on and the
battery pack detects charging current higher than a preset value, a
discharging state "b" where the charging FET 2 and the discharging
FET 3 are turned on and the battery pack detects discharging
current higher than a preset value, a charging stop state "c" where
the charging FET 2 is turned off and the discharging FET 3 is
turned on, and a discharging stop state "d" where the charging FET
2 is turned on and the discharging FET 3 is turned off. The display
unit 8 displays the state of the battery pack and the details of
the setting. In the EEPROM 10, various type of control information
for controlling state transition of the battery pack are
stored.
[0017] The microcomputer 9 performs transition operation from a
state to another state according to voltage, current and
temperature as detected and to a signal from the external host
device. Further, upon request from the external host device or at
regular interval, it transmits code data to show the current state
of the battery pack. Also, the microcomputer 9 has a function to
detect disconnection from the external host device. When
disconnection is detected, it is turned to a non-operation state
"e" where the charging FET 2 and the discharging FET 3 are turned
off beside the four types of state "a" to "d" as described above.
Here, the term "disconnection" means that it is disconnected or
separated from the external host device.
[0018] Next, description will be given on concrete examples of
state transition control and transition to each of these types of
state.
[0019] As described above, according to the present invention, the
battery voltage or the cell voltage Vb, the charging current Ic,
the discharging current Id, and the cell temperature Hb are
compared with the preset values and judgment is made to control
state transition. FIG. 2 shows examples of judgment flags to
maintain the results of comparison when this control is performed.
In FIG. 2, a judgment flag Fic1 is a flag to maintain "1" when the
charging current Ic is higher than a preset value Icrf1. A judgment
flag Fic2 is a flag to maintain "1" when the charging current Ic is
higher than a preset value Icrf2. A judgment flag Fid is a flag to
maintain "1" when the discharging current Id is higher than a
preset value Idrf1, and a judgment flag Fia is a flag to maintain
"1" when an average current Ia is lower than a preset value Iarf1.
Similarly, each of judgment flags Fvb1, Fvb2, Fvb3, Fvb4, Fvb5 and
Fvb6 is a flag to maintain "1" respectively when the battery
voltage or the cell voltage Vb is lower than a preset value Vbrf1,
when it is lower than a preset value Vbrf2, when it is higher than
a preset value Vbrf3, when it is lower than a preset value Vbrf4,
when it is lower than a preset value Vbrf5, and when it is higher
than a preset value Vbrf6. Each of judgment flags Fhb1, Fhb2, and
Fhb3 is a flag to maintain "1" respectively when the cell
temperature Hb is higher than a preset value Hbrf1, when it is
lower than a preset value Hbrf2, and when it is higher than a
preset value Hbrf3. Judgment flags Ftc1 and Ftc2 are flags to
maintain "1" when a charging time Tc, during which the charging
current Ic flows for more than a preset value Iorf1, is longer than
a preset time Tcrf1 or when normal charging time Tc is longer than
a preset time Tcrf2 under a spare charging state "f" where the
charging FET 2 and the discharging FET 3 are turned off and the
spare charging FET 4 is turned on. A judgment flag Tts is a flag to
maintain "1" when a period of time Ts in a charging temporary stop
state a2 goes beyond and is longer than a preset time Tsrf1. A
judgment flag Fo is a flag to maintain "1" when system
disconnection has been detected.
[0020] State transition control is performed according to these
judgement flags. FIG. 3 shows examples of state flags to maintain
the state to transmit code data, which indicates the present state
of the battery pack when there is a request from the external host
device or at regular interval. FIG. 4 represents examples of
processing to judge the condition for transition control and to
carry out transition control using these flags.
[0021] In the state transition control, when operation is started
at regular interval by a clock as shown in FIG. 4, for instance,
the charging current Ic or the discharging current Id is measured
(Step S11). Then, the battery voltage or the cell voltage Vb is
measured (Step S12). Further, the cell temperature Hb is measured
(Step S13), and the charging time Tc is determined (Step S14).
Also, it is judged whether it is separated and disconnected from
the external host device (Step S15) or not. If separated, the
judgement flag Fo for disconnection is turned to 1 (Step S16). If
it is not separated, the judgment flag for disconnection is turned
to 0 (Step S17). Next, the measured values Ic, Id, Vb, Hb and Tc
are compared with the preset values Icrf1, Icrf2, Idrf1, Iarf1,
Vbrf1 to Vbrf6, Hbrf1 to Hbrf3, Tcrf1, Tcrf2 and Tsrf1
respectively. Then, the judgment flags Fic1, Fic2, Fid, Fia, Fvb1
to Fvb6, Fhb1 to Fhb3, Ftc1, Ftc2, and Fts are updated (Step S18).
Then, based on these judgment flags, state transition is
controlled, and transition state flag is updated (Step S19). In
this case, it is judged whether it is necessary to transmit the
state code or not (Step S20). If it is necessary, based on the
maintaining condition of the state flag, the state code is
transmitted (Step S21). This judgment is made at the request from
the external host device or at regular interval as described
above.
[0022] FIG. 5 shows examples of state transition. Description will
be given below on concrete examples of state transition
control.
[0023] (1) In case the battery voltage or the cell voltage Vb is
lower than the preset value Vbrf1 (the judgment flag Fvb1 is set to
1), power to the microcomputer is cut off. Under the condition that
the battery pack has been charged, the supply of the power to the
microcomputer is resumed. In this case, under the condition that
the battery voltage or the cell voltage Vb is lower than the preset
value Vbrf2 (the judgement flag Fvb2 is set to 1), the charging FET
2 and the discharging FET 3 are turned off, and the spare charging
FET 4 is turned on, and it is turned to the spare charging state
"f". Also, under the condition that the microcomputer has been
started, it is turned to the spare charging state "f". Further,
under the condition that a predetermined data is not written to a
given address of nonvolatile memory, the microcomputer writes
initial data to the nonvolatile memory.
[0024] (2) In the spare charging state "f", even though the
charging time Tc, during which the charging current Ic is higher
than the preset value Icrf1 (the judgment flag Fic1 is set to 1),
is longer than the preset time Tcrf1 (the judgment flag Ftc1 is set
to 1), if the cell voltage Vb is lower than the preset value Vbrf2
(the judgment flag Fvb2 is set to 1), all of the charging FET2, the
discharging FET 3 and the spare charging FET 4 are turned off, and
it is turned to the spare charging stop state "g". The purpose of
this operation is that charging and discharging are turned to
unable status and the battery pack is turned to a status not
suitable for the use when the cell voltage is not increased even
when it is charged due to the causes such as short-circuiting
inside the cell.
[0025] (3) Pulse charging is performed by alternately turning from
a normal charging state a1 to a charging temporary stop state a2 or
vice versa. (In the normal charging state a1, the charging FET 2
and the discharging FET 3 are both turned on, and in the charging
temporary stop state a2, the charging FET 2 is turned off, and the
discharging FET 3 is turned on.) Under the condition that the cell
voltage Vb is higher than the preset value Vbrf3 (e.g. 4.25 V) (the
judgment flag Fvb3 is set to 1), it is turned to the normal
charging state a1. Under the condition that the cell voltage Vb is
lower than the preset value Vbrf4 (e.g. 4.20 V) (the judgment flag
Fvb4 is set to 1), it is turned to the charging temporary stop
state a2.
[0026] (4) Under the condition that the period of time Ts, during
which the average current Ia in a preset period of time is lower
than the preset value Iarf1 (the judgment flag Fia is set to 1) or
it is in the charging temporary stop state a2, is longer than the
preset time Tsrf1 (the judgment flag Fts is set to 1), it is turned
to the charging stop state "c". This state is defined as a charging
stop state c4 based on the full charging detection. In the charging
stop state c4 based on the full charging detection, under the
condition that the charging ratio is lower than a preset value, it
is turned to the charging state "a".
[0027] (5) In the charging state "a", under the condition that the
cell temperature Hb is higher than the preset value Hbrf1 (the
judgment flag Fhb1 is set to 1), it is turned to the charging stop
state "c", and this state is defined as a charging stop state c1
based on the temperature. Then, under the condition that the cell
temperature Hb is lower than the preset value Hbrf2 (the judgment
flag Fhb2 is set to 1), it is turned from the charging stop state
c1 based on the temperature to the charging state "a".
[0028] (6) In the charging state "a", under the condition that the
charging current Ic is higher than the preset value Icrf2 (the
judgement flag Fic2), it is turned to the charging stop state "c",
and this state is defined as a charging stop state c2 based on
abnormal current
[0029] (7) In the charging state "a", under the condition that the
cell voltage Vb is lower than the preset value Vbrf5 (the judgment
flag Fvb5 is set to 1) and does not reach full charging, even when
the charging time Tc is longer than the preset time Tcrf2 (the
judgment flag Ftc2 is set to 1), it is turned to the charging stop
state "c", and this state is defined as a charging stop state c3
based on abnormal charging time.
[0030] (8) In the charging stop state c2 based on abnormal current,
in the charging stop state c3 based on abnormal charging time, and
in the charging stop state c4 based on full charging detection, it
is turned to the discharging state "b" under the condition that
discharging has been detected, or it is turned to the non-operation
state "e" under the condition that disconnection from the system
has been detected.
[0031] (9) In the spare charging state "f", under the condition
that the cell voltage Vb is higher than the preset value Vbrf6 (the
judgment flag Fvb6 is set to 1) and disconnection of the system has
been detected (the judgment flag Fo is set to 1), it is turned to
the non-operation state "e".
[0032] (10) In the discharging state "b", under the condition that
the cell temperature Hb is higher than the preset value Hbrf3 (the
judgment flag Fhb3 is set to 1), it is turned to the charging stop
state "d", and this state is defined as a charging stop state based
on abnormal temperature.
[0033] (11) In the discharging state "b", under the condition that
the discharging current Id is higher than the preset value Idrf1
(the judgment flag Fid1 is set to 1), it is turned to the
discharging stop state "d", and this state is defined as a
discharging stop state d1 based on abnormal current.
[0034] It is needless to say that the present invention is not
limited to the above embodiment, and various changes and
modifications can be made. For instance, in the above embodiment,
the judgment flags are set. Then, the battery voltage or the cell
voltage Vb, the charging current Ic, the discharging current Id,
and the cell temperature Hb are compared with the preset values,
and the judgment flags are set to control the state transition.
This method is simply an illustrative example, and it goes without
saying that other methods may be applied to control the state
transition. Also, in the above embodiment, the code data showing
the state is transmitted at regular interval or when there is a
request from the external host device, while it is may be designed
in such manner that, when it is turned from a state to another
state in the state transition, a code data representing the state
may be transmitted at least once. This is because, if the data is
transmitted at regular interval, the period of application of
communication interrupt to the external host device is increased.
If data is transmitted only when there is a request, this cannot be
detected at accurate timing in abnormal condition. Thus, it is
aimed to transmit the state information at the timing as it is
turned to the new state. Further, it may be designed in such manner
that it is counted how much time has elapsed since it has been
turned to the current state, and this count value may be
transmitted.
[0035] As it is evident from the above description, the present
invention provides a battery pack which uses a battery comprising
one or more cells as a power source and for connecting the battery
to an external host device. The battery pack comprises
charging/discharging means connected in series to the battery and
used for charging or discharging, current detecting means for
detecting charging and discharging current of the battery, voltage
detecting means for detecting voltage of the cell, temperature
detecting means for detecting temperature of the cell, and control
means for transmitting data to the external host device at least
once when there is a request or at regular interval, whereby the
charging/discharging means is controlled according to the
charging/discharging current, voltage and temperature as detected,
and it is turned from at least one of the types of state including
charging state, discharging state, charging stop state, and
discharging stop state to another state. As a result, for the
external host device, it is easier to perform management and
control of the current state of the battery pack. The state of the
battery pack controlled according to the data such as
charging/discharging current, voltage and temperature is
transmitted to the external host device based on transition
information regarding charging state, discharging state, charging
stop state and discharging stop state.
[0036] Further, the charging/discharging means comprises a switch
for charging the battery and a switch for discharging the battery.
The control means comprises a switch for spare charging, whereby,
in charging state or discharging state, the switch for charging and
the switch for discharging are both turned on. In the charging stop
state, the switch for charging is turned off and the switch for
discharging is turned on. In the discharge stop state, the switch
for charging is turned on and the switch for discharging is turned
off, and it comprises a spare charging switch arranged in parallel
to the charging switch and the discharging switch and for charging
micro current or very small amount of current. The control means is
operated in such manner that, when the voltage is lower than the
preset value, the charging switch and the discharging switch are
turned off and only the spare charging switch is turned on, and it
is turned to the spare charging state. When the voltage is not
higher than the preset voltage value even when charging has been
performed with the preset charging current under the spare charging
state, the control means turns off the spare charging switch and it
is turned to a spare charging stop state. When it has been detected
that the connection with the external host device is disconnected,
it is turned to system disconnection. The charging switch and the
discharging switch are both turned off, and it is turned to a
non-operation state. Also, it is turned to the charging stop state
to match the state transition. The external host device can monitor
the current state of the battery pack, and it is possible to judge
how to restore to normal state promptly.
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