Apparatus and method for charging and discharging a battery
First Claim
1. An apparatus for exercising a battery, comprisinga charging circuit having a charging current output coupled to the battery;
- a temperature sensor positioned to sense a temperature related to the battery temperature;
a discharging circuit having a variable impedance load and a discharging current input coupled to the battery;
a controller coupled to said temperature sensor, said charging circuit, and said discharging circuit, said controller operable to set said charging current in accordance with said temperature, and operable to set said discharging current in accordance with said temperature, said controller being operable to minimize said charging current when said temperature is higher than a first predetermined threshold value; and
a memory coupled to said controller having a look up table with temperature versus discharging current and values of said variable impedance load stored therein, whereby said controller accesses said look up table to set said discharging current.
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Accused Products
Abstract
A method and apparatus for controlling the charge and discharge currents in a battery (2) as a function of temperature. When a battery (2) is charged or discharged in an environment that approaches its design operating temperature extreme, the currents are reduced to limit self-heating of the battery and thus extend the useful operating environment temperature range. A temperature sensor (18) is coupled to a controller (6) to sense the battery (2) temperature. The temperature information is used to set a suitable charging or discharging current (8). In the illustrative embodiment, the charging current is set to a maximum value when said temperature is lower than a first predetermined threshold value, the maximum value being the battery'"'"'s maximum specified charging current, and the first predetermined threshold value being the battery'"'"'s maximum charging temperature.
31 Citations
12 Claims
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1. An apparatus for exercising a battery, comprising
a charging circuit having a charging current output coupled to the battery; -
a temperature sensor positioned to sense a temperature related to the battery temperature; a discharging circuit having a variable impedance load and a discharging current input coupled to the battery; a controller coupled to said temperature sensor, said charging circuit, and said discharging circuit, said controller operable to set said charging current in accordance with said temperature, and operable to set said discharging current in accordance with said temperature, said controller being operable to minimize said charging current when said temperature is higher than a first predetermined threshold value; and a memory coupled to said controller having a look up table with temperature versus discharging current and values of said variable impedance load stored therein, whereby said controller accesses said look up table to set said discharging current. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of exercising a battery, comprising the steps of:
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sensing a temperature related to the battery temperature; setting a discharging current in accordance with said temperature by recalling a discharging current corresponding to said sensed temperature from a look up table; discharging the battery at said discharging current with a discharging circuit having a variable impedance load, the impedance of said load being selected from said look up table; discontinuing said discharging step when a predetermined battery voltage is reached; setting a charging current in accordance with said temperature, said setting step further including the step of minimizing said charging current when said temperature is higher than a first predetermined threshold value; and charging the battery at said charging current. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification