Battery system and management method
First Claim
1. A storage battery system runaway protection unit, comprising:
- a current sensor;
a voltage sensor connected across a series string of storage batteries;
a processor configured to accept data from the current sensor and the voltage sensor and to;
determine a charging state of the series string of storage batteries;
compute a measure of the state of charge of the series string of storage batteries;
compare a measured current of the current sensor with a state dependent threshold current;
set a threshold current and a delay time criteria for each of a fully charged state and a charging state, wherein a threshold in the charging state is related to an averaged battery string current value for the charging state; and
provide a warning or control signal output when the measured current exceeds the threshold current for a predetermined delay time.
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Accused Products
Abstract
A system and method for monitoring the status of a system of battery strings is described. The battery string current is measured by a current sensor urged into contact with a metallic element in which the battery string current is flowing. The time history of the battery string current and voltage is interpreted to determine whether the battery string is discharging, charging or in a fully charged state. A moving average current in the charging state is used to establish a threshold for determining whether a thermal runaway condition exists. The moving average is maintained at the value that existed at a time when the battery string has been disconnected from the system current bus.
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Citations
31 Claims
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1. A storage battery system runaway protection unit, comprising:
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a current sensor; a voltage sensor connected across a series string of storage batteries; a processor configured to accept data from the current sensor and the voltage sensor and to; determine a charging state of the series string of storage batteries; compute a measure of the state of charge of the series string of storage batteries; compare a measured current of the current sensor with a state dependent threshold current; set a threshold current and a delay time criteria for each of a fully charged state and a charging state, wherein a threshold in the charging state is related to an averaged battery string current value for the charging state; and provide a warning or control signal output when the measured current exceeds the threshold current for a predetermined delay time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of protecting a storage battery system from thermal runaway, comprising:
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measuring a current of a storage battery string measuring a voltage of the storage battery string; determining a charging state of battery string as one of charging, discharging or fully charged; determining the state of charge of the storage battery string; determining threshold current and delay time criteria for each of a fully charged state and a charging state, wherein a threshold in the charging state is related to an averaged battery string current value for the charging state; and providing an alarm or control signal when the threshold in the charging state or in the fully charged state is exceeded by the measured current for greater than the delay time criteria for the threshold. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A software program product, stored on a non-transitory medium, comprising:
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instructions executable by a processor to perform the steps of; measuring a current of a battery string measuring a voltage of the battery string; determining the charging state of battery string as one of charging, discharging or fully charged; determining a state of charge of the battery string; determining threshold current and delay time criteria for each of a fully charged state and a charging state, wherein a threshold in the charging state is related to an averaged battery string current value for the charging state; and providing an alarm or control signal when the threshold in a charging state or in a fully charged state is exceeded by the measured current for greater than the delay time criteria for the threshold.
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Specification