Lithium battery passivation detection
AssigneeJohnson Controls Fire Protection LP
InventorsRobert Reginald Albert Feltham, Martin A. Chiarizio, Vyacheslav Voloshin
Life of this patent
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Abstract
A method for determining lithium battery passivation starts by applying a load across a lithium battery at the start of a test interval. Measurements of the battery's voltage are taken after applying the load, and then again periodically during the test interval. A final measurement of the battery's voltage at the end of the test interval. The state of the battery is then determined based on the first and final measurements, and at least one of the periodic measurements.
Claims11
A method for determining lithium battery passivation by a detection circuit coupled with the lithium battery, comprising:
- applying a load across the lithium battery to begin a test interval;
- obtaining periodic voltage measurements of the lithium battery during the test interval;
- determining a state of the lithium battery is a passivation state in response to a voltage change between two of the periodic voltage measurements being greater than or equal to a threshold;
- determining the state of the lithium battery is a depletion state in response to the voltage change between the two of the periodic voltage measurements being less than the threshold;
- selecting and performing a depassivation process of the lithium battery from a plurality of depassivation processes in response to determining the state to be the passivation state, wherein the depassivation process is selected based on a degree of the passivation state;
- and
- sending a notification of the lithium battery being depleted in response to determining the state to be the depletion state.
A method for determining lithium battery passivation by a detection circuit coupled with the lithium battery, comprising:
- applying a load in series with the lithium battery;
- obtaining a sequence of voltage measurements, periodically during a test interval, of output voltage of the lithium battery across the load;
- matching the sequence of voltage measurements against a set of profiles;
- determining a state of the lithium battery is a passivation state in response to a profile of the set of profiles most closely matching the sequence of voltage measurements;
- determining the state of the lithium battery is a depletion state in response to a second profile of the set of profiles most closely matching the sequence of voltage measurements;
- selecting and performing a depassivation process of the lithium battery from a plurality of depassivation processes in response to determining the state to be the passivation state, wherein the depassivation process is selected based on a degree of the passivation state;
- and
- sending a notification of the lithium battery being depleted in response to determining the state to be the depletion state.
A first device in wireless communication with a second device, the first device comprising:
- an electronic circuit;
- a lithium battery configured to provide power to the electronic circuit;
- a battery test circuit configured to:
- obtain periodic voltage measurements taken during a test interval with a load across the lithium battery;
- determine a state of the lithium battery is a passivation state in response to a voltage change between two of the periodic voltage measurements being greater than or equal to a threshold;
- and
- determine the state of the lithium battery is a depletion state in response to the voltage change between the two of the periodic voltage measurements being less than the threshold;
- and
- a depassivation circuit configured to:
- select and perform a depassivation process of the lithium battery from a plurality of depassivation processes in response to determining the state to be the passivation state, wherein the depassivation process is selected based on a degree of the passivation state;
- and
- send a notification of the lithium battery being depleted in response to determining the state to be the depletion state.
Dependencies are inferred from the claim text.