Method and apparatus for battery testing
First Claim
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1. A method for testing an electrochemical battery, the method comprising:
- generating a response by applying an excitation waveform to an electrochemical battery being tested while maintaining a magnitude of the excitation waveform small enough that a relationship between the response and the excitation waveform is substantially linear;
monitoring the response;
based upon values of the response during a period which does not exceed one cycle of the excitation waveform, determining a relationship between phase and amplitude of the excitation waveform and phase and amplitude of the response.
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Abstract
A method for testing electrochemical cells applies to a portion of a cycle of a low-frequency excitation waveform to a cell under test while maintaining an amplitude of the excitation waveform below a threshold value. In some cases a quarter cycle of the excitation waveform is used. Phase an amplitude of a response to the excitation waveform may be determined by applying formulae based on geometry.
27 Citations
21 Claims
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1. A method for testing an electrochemical battery, the method comprising:
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generating a response by applying an excitation waveform to an electrochemical battery being tested while maintaining a magnitude of the excitation waveform small enough that a relationship between the response and the excitation waveform is substantially linear; monitoring the response; based upon values of the response during a period which does not exceed one cycle of the excitation waveform, determining a relationship between phase and amplitude of the excitation waveform and phase and amplitude of the response. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 21)
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12. A method for testing an electrochemical battery, the method comprising:
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generating a response by applying an excitation waveform to an electrochemical battery being tested while maintaining a magnitude of the excitation waveform small enough that a relationship between the response and the excitation waveform is substantially linear; monitoring the response; based upon values of the response during a period which does not exceed one cycle of the excitation waveform, determining a relationship between phase and amplitude of the excitation waveform and phase and amplitude of the response wherein determining a phase relationship between the excitation waveform and the response comprises performing the calculation;
or a mathematical equivalent thereof, wherein θ
is a relative phase angle, y1 is a magnitude of the response at a first time within the period, y2 is the magnitude of the response at a second time within the period, γ
=2π
ft, if is a frequency of the excitation waveform, t is a time between the first and second times.- View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
or a mathematical equivalent thereof, where A is a relative magnitude of the excitation waveform and the response.
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17. A method according to claim 16 comprising computing the relative amplitude for a plurality of pairs of first and second times to obtain a plurality of computed relative amplitudes and combining the plurality of computed relative amplitudes to provide an estimate of the relative amplitudes of the excitation waveform and response.
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18. A method according to claim 17 wherein combining the plurality of computed relative amplitudes comprises determining an average of the plurality of computed relative amplitudes.
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19. A method according to claim 17 comprising computing the relative amplitude for at least 100 pairs of first and second times within the period.
Specification