Electricity: measuring and testing – Electrolyte properties – Using a battery testing device
Reexamination Certificate
2000-04-10
2002-01-22
Toatley, Jr., Gregory J. (Department: 2838)
Electricity: measuring and testing
Electrolyte properties
Using a battery testing device
C320S134000
Reexamination Certificate
active
06340889
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a battery apparatus and a battery state monitoring circuit each of which is capable of calculating the remaining power of secondary batteries such as the lithium ion secondary batteries.
2. Description of the Related Art
As for a conventional battery state monitoring circuit, there is known the apparatus the circuit diagram of which is shown in FIG.
2
. For example, such a configuration is disclosed in Japanese Patent Application Laid-Open No. Hei 09-312172 entitled “BATTERY PACK, BATTERY CHARGER, CHARGING SYSTEM AND CHARGING METHOD”. This official gazette disclosure relates to a battery apparatus called the Smart Battery System.
Each of the lithium ion secondary batteries for use in the Smart Battery System does not have a self-protection function as in the Ni-Cd battery and hence a circuit for over-charge protection is required therefor. For this reason, a battery voltage monitor circuit
4
A for detecting the battery voltage and a switch device
12
A for stopping charging of the battery from the outside are both provided therein.
A battery apparatus
22
A receives, at a microcomputer
6
A serving as information processing means, signals A3A and A4A which have been respectively output by a current monitor circuit
3
A and a battery voltage monitor circuit
4
A to monitor the battery voltages, the charging current and the discharging current of secondary batteries
7
A,
8
A,
9
A and
10
A. Then, the microcomputer
6
A, using that information (the battery voltages, the charging current and the discharging current), calculates the remaining power of the secondary batteries
7
A,
8
A,
9
A and
10
A, and also controls the ON/OFF state of switching devices
12
A and
13
A used as current limiting means to control the charge and the discharge to and from the secondary batteries
7
A,
8
A,
9
A and
10
A.
The battery apparatus
22
A configured in such a manner carries out the display of remaining power and stops charging of the secondary batteries
7
A,
8
A,
9
A and
10
A by the microcomputer
6
A. The output voltages A3A and A4A are respectively input from a current monitor circuit
3
A and a battery voltage monitor circuit
4
A to the microcomputer
6
A which can calculate the charging current, the discharging current and the battery voltages of the secondary batteries
7
A,
8
A,
9
A and
10
A on the basis of the voltages A3A and A4A thus input thereto to calculate the remaining power of the secondary batteries. In addition, since the microcomputer
6
A carries out the ON/OFF control of the switching devices
12
A and
13
A on the basis of the state of the secondary batteries (in general, the over-charge, the over-discharge and the over-current states), the microcomputer
6
A takes on itself the safety for the protection function (the over-charge protection, the over-discharge protection and the over-current protection) in the battery apparatus
22
A.
The battery voltage monitor circuit
4
A converts the respective voltages of the secondary batteries
7
A,
8
A,
9
A and
10
A into voltages which can be read by the microcomputer
6
A to output the resultant voltages. For example, an example of a configuration of the conventional voltage monitor circuit
4
A is shown in FIG.
6
. The battery voltage monitor circuit
4
A is a circuit including a change-over switch
33
A, a battery voltage monitor amplifier
34
A and the like. The change-over switch
33
A selects the battery voltage of a respective one of the secondary batteries
7
A,
8
A,
9
A and
10
A one after the other, and the battery voltage monitor amplifier
34
A converts the battery voltage thus selected into a voltage which is can be read by the microcomputer
6
A to output as a voltage A4A to one signal line. Thus, which secondary battery is selected is determined on the basis of a control signal B4A which is controlled by the microcomputer
6
A so that the voltages of the secondary batteries are successively output to the one signal line. In this connection, while as for the control signal B4A, only one line is illustrated in
FIG. 6
, it is also conceivable as the assembly of a plurality of signals. In addition, the diagram of the switches in the change-over switch circuit
33
A shown in
FIG. 6
is a schematic expression, and hence any switch configuration may be available for use as long as it can output the battery voltages one after the other.
However, since in the conventional battery voltage monitor circuit
4
A as shown in
FIG. 6
, the battery voltages on the respective output lines of the secondary batteries
7
A,
8
A,
9
A and
10
A are successively output to the microcomputer
6
A one after the other, the following performance is required.
First of all, a large number of switches are required for the change-over switch circuit
33
A and hence a large number of signal patterns based on which of those switches are controlled are required. In addition, when the secondary batteries
7
A,
8
A,
9
A and
10
A are connected in series, the battery voltage monitor amplifier
34
A, for the reason of outputting the respective voltage values, must be a differential amplifier, and needs to have a withstanding voltage which is equal to or higher than the total voltage of the secondary batteries
7
A,
8
A,
9
A and
10
A at the lowest, and also can output or cancel the offset voltage which has been generated depending on the input voltage level.
As described above, there arises the problem that since the conventional battery voltage monitor circuit has many performance requirements, the configuration of the circuit becomes complicated, and also since a high withstanding voltage processing is also required therefor, the circuit area is increased and hence the manufacturing cost of the circuit becomes high.
SUMMARY OF THE INVENTION
In the light of the foregoing, the present invention has been made in order to solve the above-mentioned problems associated with the prior art, and it is therefore an object of the present invention to configure the battery voltage monitor circuit with a simple circuit configuration and also to monitor the battery voltages with simple method to inexpensively provide a battery state monitoring circuit and a battery pack.
In order to attain the above-mentioned object, according to an aspect of the present invention, instead of the conventional battery voltage monitor circuit, there is provided a divided battery voltage monitor circuit which is capable of dividing the total voltage of a plurality of secondary batteries connected in series and the voltage of each of the connections into respective arbitrary voltage values to output the resultant voltage values. The divided battery voltage monitor circuit is realized with a simple circuit configuration and is miniaturized. In addition, there is also adopted a battery voltage monitoring method of calculating the battery voltages on the basis of the combination of the divided battery voltage values using a microcomputer as one constituent element of the battery state monitoring circuit.
REFERENCES:
patent: 5982114 (1999-11-01), Johnson et al.
patent: 6104164 (2000-08-01), Iino et al.
patent: 6121752 (2000-09-01), Kitahara et al.
patent: 19708842 (1998-09-01), None
patent: 1041694 (2000-10-01), None
patent: 05-135792 (1993-06-01), None
patent: 11-262188 (1999-09-01), None
IBM Technical Disclosure Bulletin, “Failed Detector for Series Cell Batteries”, Oct. 1981, vol. 24, issue 5 , pp. 2248-2249.
Adams & Wilks
Seiko Instruments Inc.
Toatley , Jr. Gregory J.
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