Charge control system for batteries

Claim 2

A charging system for a battery comprising a voltage source, means for connecting said voltage source to said battery to establish a current path for charging said battery from said voltage source, temperature sensing means responsive to said battery attaining a fully charged condition for providing a corresponding output signal, and switching means connected in said current path responsive to said output signal for providing an open circuit in said current path, wherein said sensing means is responsive to the temperature of said battery exceeding a temperature external to said battery independently of ambient temperature changes.

Claim 3

The system of claim 1 wherein said sensing means is additionally independent of changes in battery temperature due to useful discharge of current from said battery.

Claim 4

The system of claim 1 wherein the battery includes a passive cell and wherein said temperature external to said active cell is the temperature of said passive cell.

Claim 5

The system of claim 3 wherein said sensing means includes heater means, said heater means having a first portion eLectrically connected to the discharge lead of said battery and having a second portion thermally connected to said passive cell so that said sensing means is responsive to the temperature of an active cell of said battery exceeding the temperature of said passive cell independently of increase in the temperature of said active cell due to current discharge.

Claim 6

The system of claim 4 wherein said sensing means includes a first thermistor for sensing the temperature of said active cell of said battery, and a second thermistor for sensing the temperature of said passive cell of said battery, and wherein said switching means includes a switching transistor circuit responsive to changes in relative resistance of said thermistors for switching on and off.

Claim 7

The system of claim 1 wherein said switching means establishes an additional current path providing a relatively low charging current for said battery.

Claim 8

The system of claim 6 wherein said connecting means includes a high charge transistor circuit for said high charging current and a low charge transistor circuit for said low charging current.

Claim 9

A charging system for a battery comprising a voltage source, means for connecting said voltage source to said battery to establish a current path for charging said battery from said voltage source, temperature sensing means responsive to said battery attaining a fully charged condition for providing a corresponding output signal, and switching means connected in said current path responsive to said output signal for providing an open circuit in said current path, wherein said sensing means is arranged for sensing the absolute battery temperature, said sensing means being responsive to said battery temperature falling out of a predetermined range and being operative for providing a corresponding output signal, and wherein said switching means connected in said current path is responsive to said latter output signal for providing an open circuit in said current path.

Claim 10

A charging system for a battery comprising a voltage source, means for connecting said voltage source to said battery to establish a current path for charging said battery from said voltage source, temperature sensing means responsive to said battery attaining a fully charged condition for providing a corresponding output signal, and switching means connected in said current path responsive to said output signal for providing an open circuit in said current path, wherein said sensing means is arranged for sensing the absolute battery temperature, said sensing means being responsive to said battery temperature falling out of a predetermined range and being operative for providing a corresponding output signal, and wherein said switching means connected in said current path is responsive to said latter output signal for providing an open circuit in said current path.

Claim 11

The system of claim 8, wherein said sensing means is responsive to the temperature of said battery exceeding a temperature external to said battery independently of ambient temperature changes.

Claim 12

The system of claim 9, wherein said sensing means is additionally independent of changes in battery temperature due to useful discharge of current from said battery.

Claim 13

The system of claim 10, wherein said switching means is arranged for maintaining said open circuit until subsequent discharge of energy from said battery.

Claim 14

The system of claim 11, wherein the battery includes a passive cell and wherein said temperature external to said active cell is the temperature of said passive cell.

Claim 15

The system of claim 12, wherein said sensing means includes heater means electrically connected to the discharge lead of said battery and thermally connected to said passive cell so that said sensing means is responsive to the temperature of an active cell of said battery exceeding a temperature external to said active cell independently of increase in the temperature of said active cell due to current discharge.

Claim 16

The system of claim 13, wherein said sensing means includes a thermistor for sensing the temperature of said active cell of said battery, and a thermistor for sensing the temperature of said passive cell of said battery, and wherein said switching means includes a switching transistor circuit responsive to changes in relative resistance of said transistors.

Claim 17

The system of claim 14, wherein said switching means establishes an additional current path providing a relatively low charging current for said battery.

Claim 18

The system of claim 15, wherein said connecting means includes a high charge transistor circuit for said high charging current and a low charge transistor circuit for said low charging current.