Battery Failure Analysis and Characterization of Failure Types 2021

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Baker Engineering and Risk Consultants, Inc.
BESS Frequency of Failure Research Topic
By Wun Wong October 8, 2021
Systems (BESS)
Battery Energy Storage
This article is an introduction to the current state of failure frequency research for
. This is the second article in a six-part series. To read other articles in this series, click here.
BESS is a subset of Energy Storage Systems (ESS), which is a system of devices intended to store energy and then release for use. BESS is specifically the type of ESS that uses a rechargeable battery for energy storage, a component to convert/release the electrical energy into motive force or to feed an electric grid/device(s), often with a Battery Management System (BMS) to control its performance and ensure safety. BESS is utilized in a multitude of applications, but the most attention is paid to the growing field of vehicular batteries for hybrid or fully electric vehicles, and stationary battery systems for electrical grids or facilities. In article one of this series, battery failures and the mechanisms of how they occur, and techniques used to evaluate them were discussed. This article discusses the frequency of such failures, which can in turn be helpful in determining the risk from such systems. Failure rate predictions of BESS are conducted with a variety of methods and with differing amounts of success. Review of literature on this topic shows that there are numerous factors that limit the accuracy and usefulness of these prediction methodologies. The primary factors are:
• BESS has many failure modes, and they are not uniformly defined. There are many different failure modes for different batteries, or under different configurations. Even among the Lithium- ion batteries (by far the most used in the market), each type has widely different characteristics with regards to fire resistance, fire and explosion propagation, and resilience to ambient conditions. This is not including factors such as manufacturing flaws, the wide range of operating conditions that BESS are subjected to, and effectiveness of the BMS. There are also non-Lithium- ion batteries with different chemical characteristics or mode of operations, such as flow batteries, which have different failure modes and risks.
• BESS reliability data is scarce. The publicly available data is limited and non-uniform. Additionally, data recorded is often in the range of fixed temperatures and with fixed cycling conditions. These conditions do not reflect the variability of real-world use.
• BESS design changes are ‘fast paced’. The drive to develop BESS with more energy density, efficiency, and higher integrity results in changes in BESS design at a high pace. This changes the potential failure modes and frequencies of BESS being modeled, and gathering potentially obsolete failure rate data from older designs.
Standard “simple” equations of component failures
A BESS consists of not only the battery cell but multiple components that can fail and cause the chain of events that result in hazards. Failure rates for BESS can be roughly estimated by conducting failure mode analysis (fault tree, FMEA, etc.) and evaluating the failure rates of each component in its system to determine the overall failure rate. Because failure rates for electronic instrumentation and components are extensively studied, there are simplified equations to estimate failure rates that are commonly used
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