High-accuracy lithium ion battery thermal runaway early warning method

Abstract

The invention relates to the technical field of lithium ion battery safety monitoring, and particularly discloses a high-accuracy lithium ion battery thermal runaway early warning method, which comprises the following steps of: obtaining a comprehensive early warning threshold value of battery thermal runaway through stress change, temperature and charging curve calculation generated during battery deformation and battery life calculation; the early warning threshold value can be used for daily maintenance and early warning judgment of the lithium ion battery energy storage system. According to the method, multiple battery data such as stress, temperature and charging and discharging data are collected at the same time and serve as the judgment basis of thermal runaway early warning, the state of the battery can be reflected more comprehensively from multiple dimensions, the accuracy of thermal runaway early warning is greatly improved, and the potential risk of thermal runaway of the battery can be found in time.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion battery safety monitoring, and in particular to a high-accuracy lithium-ion battery thermal runaway early warning method. Background Art

[0002] In recent years, the application of energy storage has become increasingly widespread. As more energy storage power plants come into operation, fires and explosions are occurring more frequently, and energy storage safety issues are attracting increasing attention. There are many causes of fires in energy storage power plants, including quality issues with the batteries and electrical equipment themselves, incomplete design of system protection measures, poor coordination of control and protection functions between systems such as the PCS, BMS, and EMS, and quality issues during construction, as well as improper operation and maintenance management, are also contributing factors. However, problems with energy storage batteries are the primary and fundamental factor in accidents such as fires and explosions in energy storage systems. Therefore, establishing a safety status model for energy storage batteries, predicting battery safety status in advance, and preventing thermal runaway are fundamental to energy storage battery safety control.

[0003] Therefore, a high-accuracy early warning method for thermal runaway of lithium-ion batteries has become an urgent problem to be solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-accuracy early warning method for thermal runaway of lithium-ion batteries. Through multi-dimensional data collection and analysis, early and accurate warning of thermal runaway of lithium-ion batteries can be achieved, and the battery life can be effectively evaluated, thereby improving the safety and reliability of lithium-ion battery use.

[0005] To solve the above technical problems, the present invention provides a technical solution: a high-accuracy lithium-ion battery thermal runaway early warning method, comprising the following steps:

[0006] S1. Collecting battery management system (BMS) data through stress sensors installed on the battery and temperature sensors installed at different locations in the battery pack;

[0007] S2. Using the charge and discharge data, determine the precursors of battery thermal runaway through calculations using a data model;

[0008] S3. Use the battery capacity, internal resistance, charge and discharge time data to determine the battery life through calculation using a data model.

[0009] Furthermore, the stress sensor is a strain gauge stress sensor, a piezoelectric stress sensor or a piezoresistive stress sensor, and the stress measured by the stress sensor is used as a judgment value for battery thermal runaway warning.

[0010] Furthermore, the temperature sensor uses a temperature sensor provided by the battery module to measure the temperature value.

[0011] Furthermore, the battery management system records charge and discharge data through a charge and discharge curve, and the charge and discharge data includes current, voltage, and capacity; and uses the percentage of the single charge capacity decay rate to the average capacity decay rate, i.e., δ%, as one of the variables for battery thermal runaway warning.

[0012] Furthermore, the battery life includes battery cycle life, internal resistance, and single charge and discharge time. These data are used to calculate the comprehensive battery life, which serves as one of the variables for battery thermal runaway warning when a sudden change occurs in the comprehensive battery life.

[0013] Furthermore, after step S3, the battery energy storage safety monitoring and management system comprehensively calculates four battery indicators, namely stress, temperature, capacity attenuation, and battery comprehensive life change, to give three thresholds of battery status, which are used for battery maintenance, replacement, and alarm processing respectively.

[0014] The advantages of the present invention compared with the prior art are:

[0015] The present invention simultaneously collects multiple battery data such as stress, temperature, charge and discharge data, and uses them as the basis for determining thermal runaway warning. It can more comprehensively reflect the battery status from multiple dimensions, greatly improving the accuracy of early warning of thermal runaway, and can promptly discover the potential risk of battery thermal runaway.

[0016] The present invention can not only determine the precursors of battery thermal runaway, but also calculate the battery life by analyzing data such as battery capacity, internal resistance, and charge and discharge time. It combines battery life assessment with thermal runaway warning to comprehensively evaluate the safety performance and health status of the battery, providing a more scientific basis for battery maintenance and management.

[0017] The present invention sets three thresholds through the battery energy storage safety monitoring and management system, corresponding to battery maintenance, replacement and alarm processing, making battery management more standardized and intelligent. When the battery status reaches the corresponding threshold, the management personnel can take timely measures to effectively reduce the probability of safety accidents such as thermal runaway of the battery, and improve the safety and reliability of battery use. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of a high-accuracy lithium-ion battery thermal runaway early warning method of the present invention. DETAILED DESCRIPTION

[0019] Various exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0020] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0021] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0022] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0023] The following is a further detailed description of a high-accuracy lithium-ion battery thermal runaway early warning method according to the present invention with reference to the accompanying drawings.

[0024] Combined with attachment Figure 1 , the present invention is introduced in detail.

[0025] A high-accuracy lithium-ion battery thermal runaway early warning method specifically comprises the following steps:

[0026] S1. Battery management system data is collected through stress sensors installed on the battery and temperature sensors installed at various locations within the battery pack. The stress sensors can be strain gauge, piezoelectric, or piezoresistive. The measured stress serves as a criterion for battery thermal runaway warning. The temperature sensors use the temperature sensors built into the battery modules to measure temperature. The battery management system records charge and discharge data through charge and discharge curves, including current, voltage, capacity, and other information.

[0027] S2. Use charge and discharge data to determine precursors to battery thermal runaway through calculations using a data model. Specifically, the percentage of the single-charge capacity decay rate to the average capacity decay rate, i.e., δ%, is used as one of the variables for battery thermal runaway warning. The data model analyzes and calculates this variable along with other charge and discharge data to determine whether the battery is experiencing precursors to thermal runaway.

[0028] S3. Use battery capacity, internal resistance, and charge / discharge time data to determine battery life through a data model calculation. Battery life includes indicators such as battery cycle life, internal resistance, and single charge / discharge time. This data is used to calculate the battery's overall lifespan. When the battery's overall lifespan suddenly changes, it serves as one of the variables for warning of battery thermal runaway.

[0029] After step S3, the battery energy storage safety monitoring and management system uses four battery indicators—stress, temperature, capacity decay, and overall battery life—to generate three thresholds for battery status. These thresholds are used for battery maintenance, replacement, and alarm processing, respectively. When each battery indicator reaches a certain threshold, the system takes appropriate measures to ensure safe battery operation.

[0030] The specific implementation process of the high-accuracy lithium-ion battery thermal runaway early warning method of the present invention is as follows:

[0031] Conduct thermal runaway tests on batteries, record the battery stress change data during the experiment, and send it to the battery energy storage safety monitoring and management system as one of the variables for battery thermal runaway warning.

[0032] Perform a charge and discharge test cycle on the battery, record the capacity change data during the battery charge and discharge process, and send it to the battery energy storage safety monitoring and management system. i =(C i -C i+1 ) / C0 for average capacity attenuation rate Percentage The amount is used as one of the variables for battery thermal runaway warning.

[0033] The battery is subjected to a charge-discharge cycle test, and the changes in capacity and charge-discharge time during the experiment are recorded and fed into the battery energy storage safety monitoring and management system. This data is used to calculate the battery's overall lifespan, which is used as a variable to warn of thermal runaway if a sudden change in the overall lifespan occurs.

[0034] Conduct thermal runaway experiments on batteries, record battery temperature changes, and send them to the battery energy storage safety monitoring and management system as one of the variables for battery thermal runaway warning.

[0035] The battery energy storage safety monitoring and management system calculates three thresholds of battery status based on stress, temperature, capacity decay, and life change.

[0036] Threshold 1 reminds users to perform battery maintenance and inspection.

[0037] Threshold 2, reminding users to replace batteries.

[0038] Threshold 3, alarm, notifying the system to take fire-fighting measures.

[0039] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A high-accuracy early warning method for thermal runaway of lithium-ion batteries, characterized in that: The following steps are involved: S1. Collect battery management system data through stress sensors installed on the battery and temperature sensors installed at different locations in the battery pack; S2. Using the charge and discharge data, determine the precursors of battery thermal runaway through calculations using a data model; S3. Use the battery capacity, internal resistance, charge and discharge time data to determine the battery life through calculation using a data model.

2. A high-accuracy lithium-ion battery thermal runaway early warning method according to claim 1, characterized in that: The stress sensor is a strain gauge stress sensor, a piezoelectric stress sensor or a piezoresistive stress sensor. The stress measured by the stress sensor is used as a judgment value for battery thermal runaway warning.

3. A high-accuracy lithium-ion battery thermal runaway early warning method according to claim 2, characterized in that: The temperature sensor measures the temperature value using the temperature sensor provided by the battery module.

4. A high-accuracy lithium-ion battery thermal runaway early warning method according to claim 3, characterized in that: The battery management system records charge and discharge data through charge and discharge curves, and the charge and discharge data includes current, voltage, and capacity. The percentage of the single charge capacity decay rate to the average capacity decay rate, i.e., δ%, is used as one of the variables for battery thermal runaway warning.

5. A high-accuracy lithium-ion battery thermal runaway early warning method according to claim 4, characterized in that: The battery life includes battery cycle life, internal resistance, and single charge and discharge time. These data are used to calculate the comprehensive battery life. When the comprehensive battery life suddenly changes, it serves as one of the variables for battery thermal runaway warning.

6. A high-accuracy lithium-ion battery thermal runaway early warning method according to claim 5, characterized in that: After step S3, the battery energy storage safety monitoring and management system uses four battery indicators, namely stress, temperature, capacity attenuation, and battery comprehensive life change, to give three thresholds for the battery status, which are used for battery maintenance, replacement, and alarm processing respectively.

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