Battery impedance detection system, apparatus and method

Abstract

Various aspects of the present invention are directed to monitoring battery cells. In accordance with various embodiments, an energy storage cell apparatus includes a current injection circuit that separately inject current into individual ones of a plurality of battery cells that store energy, and an impedance-detection circuit detects an impedance characteristic of each of the plurality of battery cells in response to the injected current. A filter circuit receives impedance data regarding the detected impedance characteristic and separates low-frequency components of the impedance data from high-frequency components of the impedance data. A memory circuit stores data corresponding to high-bandwidth data including both the low-frequency components and the high-frequency components, and an access circuit provides the low-frequency components for the plurality of battery cells to a battery pack controller. The access circuit further accesses and provides the stored high-bandwidth data for a subset of the individual battery cells to the battery pack controller based upon available bandwidth for communicating the high-bandwidth data.

Description

Background technique [0001] In many rechargeable battery applications, such as battery systems for hybrid / electric vehicles, a large number of batteries connected in series are used to generate high voltages that can be used to drive components such as the car's engine. In such systems, it is important to know the SoH (State of Health) and SoC (State of Charge) of cells connected in series (such as a battery pack). [0002] One way to estimate or determine the SoH and / or SoC includes using the impedance of the battery cell, where the impedance of the battery cell (and how it changes over time) can be used to accurately determine these characteristics. Although SoC is not usually derived directly from impedance, knowing SoH can help improve the estimate of SoC, especially when the battery cell is aging and has undergone many charge / discharge cycles. Knowing the SoH and / or SoC can also apply desired / optimal charging and discharging strategies, which can enhance battery pack lif...

AI Technical Summary

Problems solved by technology

However, many battery cell condition detection methods can require the communication and processing of large amounts of data, which can be challenging to implement in a variety of systems

For example, the available bandwidth in many battery applications, such as those implemented in automotive systems, can be relatively limited

[0004] These and other issues continue to challenge the monitoring of battery cell characteristics

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