EP0831571A2
Expired / Lapsed
EP
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Charging control system
Assignee: VLT Corp
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Filing: 1997-05-12
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Granted: —
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Expires: 2017-05-12
Abstract
Abstract A charging control system for use with a battery charger for charging a battery array which is constituted by battery cells includes charging control units corresponding individually to the battery cells. Each unit includes a voltage-regulator circuit for generating a reference voltage corresponding to the fully charged voltage of the battery cell and a comparator for comparing the inter-electrode voltage of the battery cell with the reference voltage. When the inter-electrode voltage has reached the fully charged voltage, the comparator cooperates with an amplifier to turn ON a field-effect transistor of a bypass circuit of the unit, to thereby divert the charging current from to the battery cell to the bypass circuit. The amplifier receives a feedback voltage indicating the bypass current and operates to keep the bypass current constant, thereby preventing overcharging of the battery cell.
Inventors
- 👤 Akira Kaneko
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 08:52
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/50; H02J7/52; H02J7/54; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/70
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
223 words
A charging control system for use with a battery
charger (4) for charging a battery array comprised of
serially-connected battery cells (1a, 1b, ···, 1n), characterized by: charging control units (5a, 5b, ···, 5n) which are the
same in number to the battery cells (1a, 1b, ···, 1n), each
of said charging control units being adapted to be
connected in parallel with an associated one of the battery
cells (1a, 1b, ···, 1n), said each (5) of the charging
control units includes: a bypass circuit (11) connected in parallel with the
associated one battery cell, said bypass circuit including
a semiconductor switching device (21); a reference voltage generator circuit (13) for
generating a reference voltage (V full ); a comparator circuit (25) for comparing an inter-electrode
voltage (V) of the associated one battery cell
with the reference voltage (V full ), said comparator circuit
(25) switches an operation state of said switching device
(21) from a cutoff state to a conductive state to thereby
divert a charging current (I charge ) for the associated one
battery cell to said bypass circuit (11) when the inter-electrode
voltage (V) exceeds the reference voltage
(V full ); and a bypass current adjuster circuit (15; 115) which is
operable to keep an electric current (I pass ) diverted to
and flowing through said bypass circuit (11) constant.
Claim 2
Dependent Claim
21 words
The charging control system according to claim 1,
wherein said semiconductor switching device (21) is
comprised of a high-power field-effect transistor.
Claim 3
Dependent Claim
67 words
The charging control system according to claim 1,
wherein said reference voltage generator circuit (13)
includes a step-up circuit (12) for stepping up the inter-electrode
voltage (V) of the associated one battery cell
and for outputting the thus stepped-up voltage as its
output voltage, and a voltage-regulator circuit (24) for
generating the reference voltage (V full ) based on the
output voltage of the step-up circuit (12).
Claim 4
Dependent Claim
63 words
The charging control system according to claim 1,
wherein said bypass current adjuster circuit (15) includes
an amplifier circuit (14) for receiving an output of said
comparator circuit (25), a current detection resistor (22)
inserted in said bypass circuit (11), and a feedback
resistor (26) for inversely feeding back a voltage
appearing across said current detection resistor (22) to
said amplifier circuit (14).
Claim 5
Dependent Claim
52 words
The charging control system according to claim 2,
wherein said bypass current adjuster circuit (115) includes
a resistor (122) inserted in said bypass circuit (11) and
operable to cause a drain electrode-to-source electrode
voltage of said field-effect transistor (21) to change
according to the electric current flowing through said
bypass circuit (11).
Claim 6
Dependent Claim
135 words
The charging control system according to claim 1,
wherein said reference voltage generator circuit generates
a plurality of different reference voltages (Va, Vb, ···,
Vm); said comparator circuit (25) includes a plurality of
comparators (25a, 25b, ···, 25m) connected in parallel with
one another; and each of said comparators (25a, 25b, ···, 25m) has a
first input terminal thereof directly supplied with the
inter-electrode voltage (V) of the associated one battery
cell and a second input terminal thereof supplied with a
corresponding one of the plurality of reference voltages
(Va, Vb, ···, Vm), compares the inter-electrode voltage with
the corresponding one reference voltage, and generates an
output indicating a result of the comparison, the outputs
of the plurality of comparators (25a, 25b, ···, 25m) being
added together and supplied to said semiconductor switching
device (21).
Claim 7
Dependent Claim
92 words
The charging control system according to claim 1,
wherein said each charging control unit (5) is formed into
a module structure in which said bypass circuit (11), said
reference voltage generator circuit (13), said comparator
circuit (25) and said bypass current adjuster circuit (15)
are sealed with mold-sealing; and said module structure has two connector terminals (16,
17) thereof exposed to an external surface of the module
structure and is adapted to be connected at its two
connector terminals (16, 17) with positive and negative
electrodes of the associated one battery cell.
References Cited (Backward Citations)
US4146830A
Cited
WO1984001675A1
Cited
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