JP-2026075570-A - Methods, systems, and devices for identifying and early warning characteristics of thermal runaway expansion forces in batteries.

JP2026075570AJP 2026075570 AJP2026075570 AJP 2026075570AJP-2026075570-A

Abstract

[Problem] To provide a method, system, and device for identifying and early warning of thermal runaway expansion force characteristics of batteries. [Solution] The method includes the steps of: setting a threshold and an initial expansion force value based on the characteristics of the change in expansion force during the charging and discharging process of a battery at different current rates; charging, discharging or leaving the battery to be measured at a preset current rate to obtain the current expansion force value of the battery to be measured; determining the relationship between the current expansion force value of the battery to be measured and the threshold, and if the current expansion force value is greater than or equal to the threshold, issuing a Level 1 early alarm and proceeding to the next step, otherwise returning to the previous step; calculating each expansion force peak and the time corresponding to each expansion force peak based on the current expansion force value and initial expansion force value of the battery to be measured; setting different early alarm levels and determining the early alarm level corresponding to the battery to be measured; and issuing different early alarms according to the early alarm level. [Selection Diagram] Figure 1

Inventors

章月朦
郭龍琴
林春景

Assignees

重慶理工大学

Dates

Publication Date: 20260508
Application Date: 20250310
Priority Date: 20241022

Claims (7)

Step S1 involves pre-setting a threshold and an initial expansion force value based on the characteristics of the change in expansion force during the charging and discharging process of a battery at different current rates. Step S2 involves charging or discharging the battery under test at a preset current rate or leaving it stationary, and obtaining the current expansion force value of the battery under test. Step S3 involves determining the relationship between the current expansion force value of the battery under test and the threshold value. If the current expansion force value is greater than or equal to the threshold value, a Level 1 early warning is issued, and the process proceeds to S4; otherwise, the process proceeds to S2. Step S4, which calculates each expansion force peak and the time corresponding to each expansion force peak using a peak detection algorithm based on the current expansion force value and initial expansion force value of the battery under test, wherein the expansion force peak includes a first expansion force peak, a second expansion force peak and a third expansion force peak, A method for identifying and early warning of thermal runaway expansion force characteristics of a battery, comprising step S5 of presetting different early warning levels and determining the early warning level corresponding to the battery under test based on each expansion force peak and the time corresponding to each expansion force peak.
The step of calculating each expansion force peak using the aforementioned peak detection algorithm is: Step S41 is to obtain the current expansion force value for k seconds before and k seconds after, wherein k is a constant that is not 0. Step S42 involves determining the relationship between the current expansion force value and the expansion force values at the previous k seconds and the following k seconds. If the current expansion force value is greater than or equal to the expansion force value at the previous k seconds and greater than or equal to the expansion force value at the following k seconds, it is determined that the current expansion force value is the expansion force peak. Otherwise, it is determined that the current expansion force value is not the expansion force peak. A method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to claim 1, characterized by including step S43, which involves terminating the calculation process if the current expansion force value is less than the initial expansion force value, and proceeding to S41 if the current expansion force value is greater than or equal to the initial expansion force value.
The step of pre-setting different early warning levels and determining the appropriate early warning level for the battery under test based on each inflation force peak and the time corresponding to each inflation force peak is: A step of pre-setting a first preset value and a second preset value, If a first expansion force peak is detected, the step is to issue a Level 2 early warning, If a second expansion force peak is detected, a Level 3 early warning is issued if the difference between the time corresponding to the first expansion force peak and the time corresponding to the second expansion force peak is greater than or equal to the first preset value and less than the second preset value; and a Level 4 early warning is issued if the difference between the time corresponding to the first expansion force peak and the time corresponding to the second expansion force peak is less than the first preset value. A method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to claim 1, characterized by comprising the step of issuing a level 5 early warning when a third expansion force peak is detected.
The step of obtaining the current expansion force value of the battery under test is: A method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to claim 1, characterized by including the step of obtaining the current expansion force value by installing a pressure sensor on the battery to be measured.
The method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to claim 2, characterized in that k has a positive correlation with the real-time SOC of the battery under test.
A system for identifying and early warning of thermal runaway expansion force characteristics of a battery, for performing a method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to any one of claims 1 to 5, A preset module configured to perform the step of presetting threshold and initial expansion force values based on the characteristics of changes in expansion force during the charging and discharging process of a battery at different current rates, A calculation module configured to perform the following steps: connect to a pre-configuration module, charge/discharge or leave a battery under test at a pre-configured current rate, and obtain the current expansion force value of the battery under test; determine the relationship between the current expansion force value of the battery and a threshold value, and if the current expansion force value is greater than or equal to the threshold value, issue a Level 1 early alarm and proceed to the early alarm module; otherwise, repeat the calculation in the calculation module; A system comprising an early warning module connected to a calculation module, which is configured to perform the steps of: calculating each expansion force peak and the time corresponding to each expansion force peak using a peak detection algorithm based on the current expansion force value and initial expansion force value of the battery under test, wherein the expansion force peak includes a first expansion force peak, a second expansion force peak and a third expansion force peak; and presetting different early warning levels and determining the early warning level corresponding to the battery under test based on each expansion force peak and the time corresponding to each expansion force peak.
Including the processor and memory, The electronic device is characterized in that the processor performs the steps of the method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to any one of claims 1 to 5 by calling a program or instruction stored in the memory.

Description

This specification relates to the technology of batteries, and more particularly to methods, systems, and devices for identifying and early warning of thermal runaway expansion force characteristics of batteries. [References] This application claims priority to China Application No. 202411474210.4, filed on 22 October 2024, the entire contents of which are incorporated herein by reference. In recent years, fire accidents involving new energy vehicles have been on the rise, posing one of the biggest obstacles to the commercialization of electric vehicles today. The internal structure of lithium-ion batteries is an extremely complex electrochemical system, and both normal charging and discharging processes, as well as thermal runaway processes, involve the interaction of various processes including electricity, thermodynamics, chemistry, mechanics, and gas generation dynamics. Current methods for early warning of thermal runaway in lithium-ion batteries primarily rely on voltage, temperature, internal resistance, emitted gases, and smoke. However, these methods cannot provide a timely response or early warning of thermal runaway within the battery. When thermal runaway occurs, the expansion force signal appears earlier than conventional early warning signals such as voltage and temperature, and changes as the thermal runaway progresses. Therefore, there is a need to provide methods, systems, and devices for identifying and early warning of thermal runaway expansion force characteristics in batteries, which can help in timely and accurate determination of the thermal runaway state and provide timely early warnings. This is a flowchart illustrating a method for identifying and early warning of thermal runaway expansion force characteristics of a battery according to the embodiments described herein.This is a schematic diagram of the expansion force peaks and corresponding times identified by a peak detection algorithm during the thermal runaway process at SOC = 110% in a 51Ah rectangular hard-shell ternary/graphite cell according to the embodiments of this specification.This is a schematic diagram of the expansion force peaks and corresponding times identified by a peak detection algorithm during the thermal runaway process at SOC = 100% in a 51Ah rectangular hard-shell ternary/graphite cell according to the embodiments of this specification.This is a schematic diagram of the expansion force peaks and corresponding times identified by a peak detection algorithm during the thermal runaway process at SOC = 50% in a 51Ah rectangular hard-shell ternary/graphite cell according to the embodiments of this specification.This is a schematic diagram of the expansion force peaks and corresponding times identified by a peak detection algorithm during the thermal runaway process at SOC = 25% in a 51Ah rectangular hard-shell ternary/graphite cell according to the embodiments of this specification.This is a schematic diagram of the expansion force peaks and corresponding times identified by a peak detection algorithm during the thermal runaway process at SOC = 0% in a 51Ah rectangular hard-shell ternary/graphite cell according to the embodiments of this specification. To more clearly illustrate the technical means of the embodiments described herein, the drawings necessary for describing the embodiments are briefly described below. Clearly, the drawings described below are only examples or embodiments of this specification, and those skilled in the art can apply this specification to other similar scenarios based on these drawings without requiring any creative effort. Unless otherwise stated or made clear from the context, the same reference numerals in the figures represent the same structure or operation. It should be understood that the terms “system,” “apparatus,” “unit,” and/or “module” as used herein are ways of distinguishing various assemblies, elements, components, parts, or assemblies of different levels. However, other terms may be used in place of the above terms if they can achieve the same purpose. As described herein and in the claims, unless the context explicitly indicates otherwise, terms such as “one,” “one,” “one kind,” and/or “the” do not specifically refer to the singular form and may include the plural form. Generally, the terms “includes” and “contains” merely indicate the inclusion of clearly identified steps and elements, and these steps and elements are not an exclusive list; the method or device may include other steps or elements. This specification uses flowcharts to describe the operations performed by the systems in the embodiments described herein. It should be understood that the preceding and succeeding operations are not necessarily performed in exact order. Instead, each step may be performed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes. Thermal runaway is an abnormal phenom