BATTERY CHARGING SYSTEM WITH MEANS FOR SENSING CURRENT, VOLTAGE, GASSING AND TEMPERATURE

• US 3,652,915 A
• Filed: 04/02/1970
• Issued: 03/28/1972
• Est. Priority Date: 04/02/1970
• Status: Expired due to Term

• Current Assignee: Klaus Eberts
• Original Assignee: Klaus Eberts
• Inventors: Eberts, Klaus
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/025,045
• Time in Patent Office: 726 Days
• Field of Search: 320/35,36,46,52,61,DIG.1,39,40 200/81.6,152.9 338/36,39
• US Class Current: 320/141
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007188 the charge cycle being controlled or terminated in response to non-electric parameters

Abstract

A battery charging system has electronic control means for reducing the charging current in response to attainment of a predetermined battery terminal voltage, a predetermined temperature of the battery and/or a predetermined gassing rate of the battery, and for terminating the charging current when same falls below a predetermined low limit.

Claims

1. Apparatus for charging a battery, comprising a source of unidirectional charging current, a pair of output terminals for connection with a battery to be charged, an electrical charging circuit for supplying charging current from said source to said terminals, a transistor having emitter and collector connected in series with said charging circuit for controlling the flow and magnitude of the charging current in response to at least one of a plurality of control signals applied to the base of said transistor, voltage sensing means connected across said output terminals and providing one of said control signals when the voltage across said output terminals rises to a predetermined value, temperature sensing means mounted in heat-exchange relationship with said battery and responsive to the temperature of said battery for providing one of said control signals when said temperature rises to a predetermined value, gas-pressure sensing means coordinated to the interior space of said battery and responsive to the gas-pressure therein for providing one of said control signals when the gas-pressure within said battery rises to a predetermined value, circuit means connected to said above means and to said base of said transistor to decrease the conductivity of saId transistor and to diminish charging current in response to said signals, and current sensing means connected to said circuit and said base and responsive to the magnitude of the charging current to render said transistor conductive when the magnitude of said charging current exceeds a predetermined lower limit, and to render said transistor non-conductive when the magnitude of said charging current drops below said limit, the gas-pressure sensing means comprising a cylinder adapted to communicate at one end with said interior of said battery to receive gas therefrom, a piston slidable in said cylinder, a pressure sensitive device arranged in said cylinder at its opposite end, and a spring disposed in said cylinder between said piston and said pressure sensitive device, said cylinder having a port in its wall through which gas can escape from said cylinder when said piston has moved a predetermined distance in said cylinder towards said device due to increasing gas pressure.

2. Battery charging apparatus comprising a source of unidirectional charging current, a pair of output terminals for connection with a battery to be charged, an electrical charging circuit for supplying charging current from said source to said terminals, a power transistor having emitter and collector connected in series with said charging circuit for controlling the flow and magnitude of the charging current in response to at least one of a plurality of control signals applied to the base of said transistor, voltage sensing means connected across said output terminals and providing one of said control signals when the voltage across said output terminals rises to a predetermined value, temperature sensing means mounted in heat-exchange relationship with said battery and responsive to the temperature of said battery for providing one of said control signals when said temperature rises to a predetermined value, gas-pressure sensing means coordinated to the interior space of said battery and responsive to the gas-pressure therein for providing one of said control signals when the gas-pressure within said battery rises to a predetermined value, circuit means connected to said above means and to said base of said transistor to decrease the conductivity of said transistor and to diminish charging current in response to said signals, and current sensing means connected to said circuit and said base and responsive to the magnitude of the charging current to render said transistor conductive when the magnitude of said charging current exceeds a predetermined lower limit, and to render said transistor non-conductive when the magnitude of said charging current drops below said limit, said gas-pressure sensing means comprising a cylinder adapted to communicate at one end with said interior of said battery, a gas-pressure actuated body of electrically conductive material slidable in said cylinder, a plurality of electrical contacts provided in spaced relation to one another along the length of said cylinder to be contacted successively by said body as it moves longitudinally in said cylinder due to increasing gas pressure, said cylinder having a port in its wall through which gas can escape when said body has moved a predetermined distance in said cylinder towards its opposite end, said contacts being electrically connected to a resistor element at spaced points along the length thereof, said resistor element being included in the base circuit of a control transistor having its emitter connected to said charging circuit and having its collector connected to said base of said power transistor.

3. Battery charging apparatus comprising a source of unidirectional charging current, a pair of output terminals for connection with a battery to be charged, an electrical charging circuit for supplying charging current from said source to said terminals, a power transistor having emitter and collector connected in series With said charging circuit for controlling the flow and magnitude of the charging current in response to at least one of a plurality of control signals applied to the base of said transistor, voltage sensing means connected across said output terminals and providing one of said control signals when the voltage across said output terminals rises to a predetermined value, temperature sensing means mounted in heat-exchange relationship with said battery and responsive to the temperature of said battery for providing one of said control signals when said temperature rises to a predetermined value, gas-pressure sensing means coordinated to the interior space of said battery and responsive to the gas-pressure therein for providing one of said control signals when the gas-pressure within said battery rises to a predetermined value, circuit means connected to said above means and to said base of said transistor to decrease the conductivity of said transistor and to diminish charging current in response to said signals, and current sensing means connected to said circuit and said base and responsive to the magnitude of the charging current to render said transistor conductive when the magnitude of said charging current exceeds a predetermined lower limit, and to render said transistor non-conductive when the magnitude of said charging current drops below said limit, said gas-pressure sensing means comprising a gas-pressure operated body sliding in a cylinder which is adapted to communicate at one end with the interior space of said battery to move said body in said cylinder upon increase of gas pressure in said battery, and a pressure sensitive device disposed at the opposite end of said cylinder to generate a control signal upon movement of said body towards said pressure sensitive device, said cylinder having a port in its wall for escape of the gas from said cylinder, said port being disposed at a point along the length of said cylinder wall normally to be closed by said body but to be opened upon movement of said body towards said device, said pressure sensitive device comprising a pressure sensitive resistor, a control transistor having its base connected to said pressure sensitive resistor, its emitter connected to said charging circuit, and its collector connected to said base of said power transistor.

4. Battery charging circuit as claimed in claim 1, wherein said pressure sensitive device comprises a pressure sensitive resistor, a control transistor having its base connected to said pressure sensitive resistor, its emitter connected to said charging circuit, and its collector connected to said base of said power transistor.