A thermal runaway comprehensive alarm method and system for a lithium-ion battery energy storage power station

Abstract

The present application relates to the field of thermal runaway early warning of energy storage power station, and particularly relates to a lithium ion battery energy storage power station thermal runaway comprehensive warning method and system.The method comprises the following steps: when the battery temperature does not exceed the set temperature T1, judging whether the battery is in a charging or discharging state; when the battery is in a charging or discharging state: when the battery temperature is in a first temperature interval [T3, T2], judging whether the battery temperature rise exceeds the set first temperature rise threshold value: if yes, triggering a first level alarm; when the battery temperature is in a second temperature interval [T2, T1], judging whether the battery temperature rise exceeds the set second temperature rise threshold value, whether the voltage exceeds the set voltage change threshold value and whether gas is generated: if any of the above is yes, triggering a second level alarm; when the battery temperature exceeds T1, judging whether the battery temperature rise exceeds the set third temperature rise threshold value and whether gas is generated: if any of the above is yes, triggering a third level alarm.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thermal runaway early warning of energy storage power stations, in particular to a lithium ion battery energy storage power station thermal runaway comprehensive warning method and system. BACKGROUND

[0002] With the widespread adoption of renewable energy sources such as wind and solar energy, energy storage technology has become increasingly important. Energy storage systems can balance energy supply and demand, improve the stability of the power grid, reduce the environmental impact of energy systems, and increase the flexibility of the power system. Among them, lithium ion batteries are one of the most commonly used energy storage technologies, widely used in electric vehicles, home energy storage and industrial energy solutions. However, a key problem in energy storage systems is thermal runaway. Thermal runaway events can cause fires, battery damage, battery aging and system failure, posing potential threats to personnel safety, the environment and the reliability of energy storage systems. Therefore, the prevention and management of thermal runaway is crucial to ensure the performance, reliability and safety of energy storage systems.

[0003] Prior art I related to the present application

[0004] Technical solution of prior art I

[0005] Chinese invention application with publication number CN115842183A discloses a thermal runaway early warning system and method for lithium ion battery energy storage cabin. The system uses multiple detection devices, including a pressure detection module, a sound detection module and a particle detection module, installed in the shell of the battery pack unit. The monitoring host is connected to the detection modules of all detection devices and is used to receive and analyze monitoring signals, and triggers an alarm when an abnormal signal is received.

[0006] The disadvantage of prior art I is that the technology uses a series of detection modules and sensors to alarm thermal runaway. However, for large-scale energy storage systems, a large number of detection devices need to be installed and managed, increasing the cost and complexity of the system, and requiring higher technical personnel in the later maintenance.

[0007] Prior art II related to the present application

[0008] Technical solution of prior art II

[0009] The Chinese invention application with the publication number CN116706296A provides a battery system thermal runaway monitoring method, by controlling the opening of the valves corresponding to all single batteries in the battery system, obtaining the gas inside all single batteries in the battery system, and analyzing and judging whether the battery system has a thermal runaway risk; if the battery system has a thermal runaway risk, then control the opening of the valves corresponding to all single batteries in each battery module, respectively, obtain the gas inside all single batteries in each battery module, and analyze and judge whether each battery module has a thermal runaway risk.

[0010] Disadvantages of prior art two

[0011] This technology only determines the thermal runaway risk through gas, and in actual situations, the appearance of gas may have been in the middle or later stage of thermal runaway, which has a certain delay in the aspect of alarm, and time is needed to open and close the valves of each single battery to obtain the gas sample, especially in large battery systems, there may be a large time delay. This means that the monitoring system may not be able to detect a rapidly developing thermal runaway situation in time. SUMMARY

[0012] The purpose of the present application is to overcome the problems existing in the prior art. In the energy storage system, most of the thermal runaway is caused by the abnormal state of the battery. The present application analyzes the stage of thermal runaway development and the battery temperature statistics based on the existing energy storage container operation data, and designs a thermal runaway grading alarm system with strong real-time performance, easy integration, fast alarm and linkage to fire.

[0013] To achieve the above purpose, the present application realizes the following technical solutions.

[0014] The present application proposes a lithium ion battery energy storage power station thermal runaway comprehensive alarm method, the method comprising:

[0015] Collecting battery data, including temperature and voltage; detecting whether the battery produces gas and making a judgment:

[0016] When the battery temperature does not exceed the set temperature T1, judge whether the battery is in charging or discharging state:

[0017] When the battery is in charging or discharging state, judge the relationship between the battery temperature and the set first temperature interval [T3, T2] and second temperature interval [T2, T1], T3 < T2 < T1:

[0018] When the battery temperature is in the first temperature interval, judge whether the battery temperature rise exceeds the set first temperature rise threshold: if yes, trigger a first level alarm;

[0019] When the battery temperature is in the second temperature interval, it is determined whether the battery temperature rise exceeds a set second temperature rise threshold, whether the voltage exceeds a set voltage change threshold, and whether gas is generated: when any of the above is yes, a secondary alarm is triggered;

[0020] When the battery temperature exceeds T1, it is determined whether the battery temperature rise exceeds a set third temperature rise threshold and whether gas is generated: when any of the above is yes, a tertiary alarm is triggered.

[0021] As one of the improvements of the above technical solutions, it is determined whether the battery temperature rise exceeds a set first temperature rise threshold: when the battery temperature rise exceeds the first temperature rise threshold, a primary alarm is triggered, including:

[0022] The first temperature interval is divided into a plurality of sub-intervals;

[0023] The temperature rise of each sub-interval is calculated, and when the temperature rise of any sub-interval is greater than the maximum temperature rise threshold set for the sub-interval, it is determined to be abnormal;

[0024] Starting from the time when the abnormality is triggered, it is determined whether the temperature rise in the future period of time meets a set rising trend temperature rise threshold, and if so, a primary alarm is triggered.

[0025] As one of the improvements of the above technical solutions, it is determined whether the battery temperature rise exceeds a set second temperature rise threshold: when the battery temperature rise exceeds the second temperature rise threshold, a secondary alarm is triggered, including:

[0026] The second temperature interval is divided into a plurality of sub-intervals;

[0027] The temperature rise of each sub-interval is calculated, and when the temperature rise of any sub-interval is greater than the maximum temperature rise threshold set for the sub-interval, it is determined to be abnormal;

[0028] Starting from the time when the abnormality is triggered, it is determined whether the temperature rise in the future period of time meets a set rising trend temperature rise threshold, and if so, a secondary alarm is triggered.

[0029] As one of the improvements of the above technical solutions, it is determined whether the battery voltage change exceeds a set voltage change threshold: when the set voltage change threshold is exceeded, a secondary alarm is triggered, including:

[0030] Real-time voltage data is collected, and the collected data is linearly fitted to obtain the slope of the fitted straight line;

[0031] The obtained slope is compared with the set voltage change threshold: when the obtained slope is less than the set voltage change threshold, a secondary alarm is triggered.

[0032] As one of the improvements of the above technical solutions, when the battery temperature is in the second temperature interval, it is determined whether the generated gas is H2.

[0033] As one of the improvements of the above technical solutions, whether the battery temperature rise exceeds the set third temperature rise threshold is judged, and when the battery temperature rise exceeds the third temperature rise threshold, a third level alarm is triggered, including:

[0034] The battery temperature rise is calculated, and whether the battery temperature rise is greater than the set third temperature rise threshold is judged.

[0035] When the battery temperature rise is greater than the third temperature rise threshold, whether the temperature of the adjacent battery is greater than T2 is judged, and if the temperature of the adjacent battery is greater than T2, the third level alarm is triggered.

[0036] As one of the improvements of the above technical solutions, when the battery temperature exceeds T1, whether the generated gas is CO is judged.

[0037] The present application provides a kind of lithium ion battery energy storage power station thermal runaway comprehensive alarm system, the system includes: data acquisition module, gas detection device and thermal runaway grading early warning module;Wherein,

[0038] The data acquisition module is used to collect the battery data of energy storage power station, including: temperature and voltage;

[0039] The gas detection device is used to detect whether the battery generates gas;

[0040] The thermal runaway grading early warning module is used to receive the data collected by the data acquisition module and the detection result of the gas detection device to judge:

[0041] When the battery temperature does not exceed the set temperature T1, whether the battery is in charging or discharging state is judged:

[0042] When the battery is in charging or discharging state, the relationship between the battery temperature and the set first temperature interval [T3, T2] and the second temperature interval [T2, T1] is judged:

[0043] When the battery temperature is in the first temperature interval, whether the battery temperature rise exceeds the set first temperature rise threshold is judged: if yes, the first level alarm is triggered.

[0044] When the battery temperature is in the second temperature interval, whether the battery temperature rise exceeds the set second temperature rise threshold, whether the voltage exceeds the set voltage change threshold and whether gas is generated are judged: when any one of them is yes, the second level alarm is triggered;Supplement the relationship of first temperature interval and second temperature interval and T1

[0045] When the battery temperature exceeds T1, whether the battery temperature rise exceeds the set third temperature rise threshold and whether gas is generated are judged: when any one of them is yes, the third level alarm is triggered.

[0046] As one of the improvements of the above technical solutions, the system further comprises a fire-fighting host;

[0047] The fire-fighting host is configured to perform fire-fighting treatment according to the alarm result triggered by the thermal runaway grading early warning module.

[0048] As one of the improvements of the above technical solutions, the system further comprises an audible light alarm, a ventilation device and a fire extinguishing device.

[0049] Compared with the prior art, the present application has the following advantages:

[0050] The thermal runaway early warning system of the present application is based on in-depth research on the development law of thermal runaway events and the statistics of related operation data, and realizes more accurate and early alarm parameter setting; compared with the traditional method, the system can accurately capture and quickly respond to abnormal battery temperature, thereby effectively reducing the potential safety risk and performance decline. In addition, the unique linkage fire-fighting host function also provides an important guarantee for the safety of the system, and once the thermal runaway event further deteriorates, the system will take loss-limiting measures in time, reducing the risk of fire and equipment damage. In summary, the present application not only can protect the stable operation of the energy storage system, but also helps to prolong the life of the battery and improve the reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a method flowchart of the present application;

[0052] Figure 2 is a temperature criterion flowchart;

[0053] Figure 3 is the system structure related to the present application as a whole. DETAILED DESCRIPTION

[0054] The present research proposes a complete and real-time comprehensive thermal runaway grading early warning system, which can provide real-time early warning in the early stage of thermal runaway, and provide more reliable, efficient and safe solutions for future energy storage system design and operation, and promote the wider application of sustainable energy.

[0055] The technical solutions of the present application will be described in detail below in combination with the drawings and examples.

[0056] Example 1

[0057] As shown in Figure 1 is a method flowchart of the present application, the present application divides thermal runaway alarm into three levels: the first level alarm is the lightest, and the third level alarm is the most serious. As shown in Figure 1As shown, the first level alarm starts at the battery temperature of 35-55℃ under the charging and discharging condition, and the temperature rise criterion is used as the condition to trigger the first level alarm signal to the PCS (energy storage converter), the PCS cuts off the DC side, and issues the standby instruction. In addition to the temperature rise criterion, the second level alarm has two other criteria, namely hydrogen and voltage, and any one of the three criteria triggers the second level alarm. After triggering, the PCS AC side and each cluster breaker are cut off, and the audible and light alarm is triggered. If there is hydrogen, the ventilation equipment needs to be turned on.

[0058] The complete alarm triggering logic and parameter setting provided by the embodiment of the present application are described as follows.

[0059] The present application classifies the alarm of the battery and the energy storage cabin from multiple angles, and the criteria include temperature criterion, voltage criterion, and temperature and gas comprehensive criterion. In addition, the present application sets the second judgment condition after triggering in the temperature criterion to avoid abnormal BMS data acquisition, which can effectively avoid false reports and disorderly reports caused by abnormal values.

[0060] 1. First level alarm

[0061] 1) Temperature rise criterion

[0062] ①Calculation premise: the battery temperature is between 35-55℃, and is in the charging and discharging state.

[0063] ②Temperature rise criterion: divide 35-55℃ into two intervals of 35-45℃ and 45-55℃, respectively, and preset the maximum temperature rise threshold of 30s / 1min / 5min in each interval for rolling calculation. Any value greater than the preset maximum temperature rise value can be preliminarily determined as abnormal; if all values are not greater than the preset maximum temperature rise value, no pre-warning is performed. In order to exclude the influence of abnormal values in data acquisition, a verification strategy is set after triggering the abnormality to determine the rising trend. Specifically, set the maximum temperature rise threshold within 15s, take the time when the abnormality is triggered as the starting point, and determine whether the temperature rise within the subsequent 15s / 15-30s meets the threshold set for the rising trend. If yes, the first level alarm is triggered. For example, Figure 2 As shown, it is a temperature criterion flowchart.

[0064] 2) Control strategy

[0065] Send alarm signal, cut off PCS DC side, PCS to standby (issue standby command to PCS), and verify battery condition.

[0066] 3) Alarm release condition

[0067] Set the normal temperature rise condition as the threshold value, and calculate the temperature rise every 15 seconds with a 15-second cycle. If the temperature rise is less than the threshold value for two consecutive times and the battery temperature is lower than 45℃, the alarm can be removed.

[0068] 2. Secondary alarm

[0069] The secondary alarm includes temperature criteria, voltage criteria, and temperature and gas combined criteria. If any of them is triggered, the secondary alarm will be triggered. If none of them is triggered, no alarm will be given.

[0070] 1) Temperature criteria

[0071] ① Calculation premise: The battery temperature is between 55-85℃, and it is in the charging or discharging state.

[0072] ② Temperature rise criteria: Divide 55-85℃ into two intervals, 55-65℃ and 65-85℃. Set the maximum temperature rise threshold values for 30s / 1min / 5min in the initial temperature interval 55-65℃ and 5s / 10s / 30s in the initial temperature interval 65-85℃, and calculate them rolling. If any of them is greater than the set maximum temperature rise value, it can be preliminarily determined as abnormal. If all of them are not greater than the set maximum temperature rise value, continue rolling calculation. For the same level of alarm, to exclude the influence of abnormal values in data sampling, set a verification strategy after triggering the abnormality. Specifically, set the maximum temperature rise threshold value for 15s in the initial temperature interval 55-65℃, and set the threshold value for the rising trend of the temperature rise in the subsequent 15s / 15-30s based on the initial time of the abnormality. Set the maximum temperature rise threshold value for 5s in the initial temperature interval 65-85℃, and set the threshold value for the rising trend of the temperature rise in the subsequent 5s / 5-10s / 10-15s based on the initial time of the abnormality. If it meets the threshold value, trigger the secondary alarm. If it does not meet the threshold value, do not alarm.

[0073] 2) Voltage criteria

[0074] ① Calculation premise: The battery is in the charging state.

[0075] ② Voltage criteria: First, detect that the voltage is ≥5V, record the current voltage U0, and record the current time as T0. Then, collect the voltage values for the next 30s every 5s starting from T0, remove the maximum and minimum values of the 30 voltage points (a total of 28 points), and perform linear fitting. If the slope is <-0.2mV / s, the voltage criteria is met.

[0076] 3) Temperature and gas criteria

[0077] Judgment basis: The temperature is greater than 55℃, and there is H2.

[0078] 4) Control strategy

[0079] Disconnect the PCS AC side and all cluster circuit breakers; trigger the fire alarm with sound and light; if H2 is present, turn on the energy storage compartment ventilation equipment.

[0080] 5) Alarm cancellation conditions

[0081] The alarm will be deactivated if the battery temperature returns to below 55°C.

[0082] 3. Level 3 Alarm

[0083] The Level 3 alarm includes temperature criteria and a combined temperature and gas criterion; triggering any one of these criteria will activate the Level 3 alarm. If neither is triggered, no alarm will be issued.

[0084] 1) Temperature Criteria

[0085] ① Calculation premise: Battery temperature is greater than 85℃.

[0086] ② Temperature rise criterion: When the battery temperature is greater than 85℃, a maximum temperature rise threshold of 5 seconds is set, and then the temperature rise of 5 seconds is calculated in a rolling manner. After the set maximum temperature rise threshold of 5 seconds is met, it is necessary to determine that the temperature of its adjacent battery is also greater than 55℃, and then a level 3 alarm is triggered.

[0087] 2) Temperature and Gas Criteria

[0088] Judgment criteria: temperature greater than 85℃, adjacent battery temperature greater than 55℃ and presence of CO.

[0089] 3) Control Strategy

[0090] Disconnect the PCS AC side and each cluster of circuit breakers, spray fire-fighting agents, trigger the fire alarm with sound and light, and turn on the ventilation equipment of the energy storage compartment.

[0091] 4) Alarm cancellation conditions

[0092] The alarm was lifted after the relevant staff determined that there was no abnormality.

[0093] No strategy judgment or alarm will be performed when the temperature is not higher than 85℃ and the device is not in a charging or discharging state.

[0094] Example 2

[0095] like Figure 3 The diagram shows the overall system structure involved in this invention. The thermal runaway alarm strategy is deployed to the BMS (Battery Management System) as needed and linked with systems such as the fire alarm control panel. Data such as temperature, voltage, and gas are transmitted to the BMS for relevant logical calculations and the issuance of alarm signals at different levels. The fire alarm control panel is responsible for receiving signals and taking fire-fighting measures to control the development of thermal runaway in a timely manner.

[0096] Finally, it should be noted that the above examples are merely used to illustrate the technical solutions of the present application but not to limit. Although the present application is explained in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A comprehensive alarm method for thermal runaway in a lithium-ion battery energy storage power station, the method comprising: Collect battery data, including temperature and voltage; detect and determine whether the battery is producing gas. When the battery temperature does not exceed the set temperature T1, determine whether the battery is in a charging or discharging state: When the battery is in a charging or discharging state, determine the relationship between the battery temperature and the set first temperature range [T3,T2] and second temperature range [T2,T1]: When the battery temperature is in the first temperature range, determine whether the battery temperature rise exceeds the set first temperature rise threshold: if it is determined to be yes, trigger a level one alarm. When the battery temperature is in the second temperature range, it is determined whether the battery temperature rise exceeds the set second temperature rise threshold, whether the voltage exceeds the set voltage change threshold, and whether gas is generated: if any one of these is determined to be true, a second-level alarm is triggered. Determine whether the battery voltage change exceeds the set voltage change threshold. If it does, trigger a secondary alarm, including: Voltage data is acquired in real time, and linear fitting is performed on the acquired data to obtain the slope of the fitted line; The obtained slope is compared with a set voltage change threshold: when the obtained slope is less than the set voltage change threshold, a secondary alarm is triggered; the set voltage change threshold is -0.2mV / s. The condition for clearing the level 2 alarm is: the battery temperature is below T2; When the temperature criterion or the combined temperature and gas criterion is met, a level 3 alarm is triggered. The temperature criterion is: the battery temperature is greater than T1, and the temperature rise reaches the set third temperature rise threshold within a set time period, and the temperature of adjacent batteries is greater than 55°C. The combined temperature and gas criterion is: the battery temperature is greater than T1, the temperature of adjacent batteries is greater than 55°C, and gas is present. The Level 3 alarms are resolved by manual judgment. T1 is 85°C; T2 is 55°C; and T3 is 35°C.

2. The integrated alarm method for thermal runaway in lithium-ion battery energy storage power stations according to claim 1, characterized in that, Determine if the battery temperature rise exceeds the set first temperature rise threshold: When the battery temperature rise exceeds the first temperature rise threshold, a level one alarm is triggered, including: The first temperature range is divided into multiple sub-ranges; Calculate the temperature rise of each sub-interval. If the temperature rise of any sub-interval exceeds the maximum temperature rise threshold set for that sub-interval, it is judged as abnormal. Starting from the time the anomaly was triggered, it is determined whether the temperature rise in the future meets the set upward trend temperature rise threshold. If it does, a level one alarm is triggered.

3. The integrated alarm method for thermal runaway in lithium-ion battery energy storage power stations according to claim 1, characterized in that, Determine if the battery temperature rise exceeds the set second temperature rise threshold. When the battery temperature rise exceeds the second temperature rise threshold, trigger a level two alarm, including: The second temperature range is divided into multiple sub-ranges; Calculate the temperature rise of each sub-interval. If the temperature rise of any sub-interval exceeds the maximum temperature rise threshold set for that sub-interval, it is judged as abnormal. Starting from the time the anomaly was triggered, it is determined whether the temperature rise in the future meets the set upward trend temperature rise threshold. If it does, a level 2 alarm is triggered.

4. The integrated alarm method for thermal runaway in lithium-ion battery energy storage power stations according to claim 1, characterized in that, When the battery temperature is in the second temperature range, determine whether the generated gas is H2.

5. The integrated alarm method for thermal runaway in lithium-ion battery energy storage power stations according to claim 1, characterized in that, When the battery temperature exceeds T1, determine whether the generated gas is CO.

6. A comprehensive alarm system for thermal runaway in a lithium-ion battery energy storage power station, implemented based on the method described in any one of claims 1-5, characterized in that, The system includes: a data acquisition module, a gas detection device, and a thermal runaway graded early warning module; wherein... The data acquisition module is used to collect battery data from the energy storage power station, including temperature and voltage. The gas detection device is used to detect whether the battery is producing gas; The thermal runaway graded early warning module is used to receive data collected by the data acquisition module and the detection results of the gas detection device for judgment: When the battery temperature does not exceed the set temperature T1, determine whether the battery is in a charging or discharging state: When the battery is in a charging or discharging state, determine the relationship between the battery temperature and the set first temperature range [T3, T2] and second temperature range [T2, T1]. <T2<T1: When the battery temperature is in the first temperature range, determine whether the battery temperature rise exceeds the set first temperature rise threshold: if it is determined to be yes, trigger a level one alarm. When the battery temperature is in the second temperature range, it is determined whether the battery temperature rise exceeds the set second temperature rise threshold, whether the voltage exceeds the set voltage change threshold, and whether gas is generated: if any one of these is determined to be true, a second-level alarm is triggered. When the temperature criterion or the combined temperature and gas criterion is met, a level 3 alarm is triggered. The temperature criterion is: the battery temperature is greater than T1, and the temperature rise reaches the set third temperature rise threshold within a set time period, and the temperature of adjacent batteries is greater than 55°C. The combined temperature and gas criterion is: the battery temperature is greater than T1, the temperature of adjacent batteries is greater than 55°C, and carbon monoxide gas is present.

7. The integrated alarm system for thermal runaway of a lithium-ion battery energy storage power station according to claim 6, characterized in that, The system also includes a fire control panel; The fire control panel is used to perform fire-fighting operations based on the alarm results triggered by the thermal runaway graded early warning module.

8. The integrated alarm system for thermal runaway of a lithium-ion battery energy storage power station according to claim 6, characterized in that, The system also includes: audible and visual alarms, ventilation equipment, and fire extinguishing devices.

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