CN-122025880-A - Thermal runaway protection method and system for immersed liquid-cooled battery energy storage system

CN122025880ACN 122025880 ACN122025880 ACN 122025880ACN-122025880-A

Abstract

The application relates to the technical field of safety of an electrochemical energy storage system and discloses a thermal runaway protection method and a thermal runaway protection system for an immersed liquid-cooled battery energy storage system, wherein the method comprises the steps of monitoring vibration signals on the surface of a sealed box body through a vibration sensor array arranged outside the sealed box body, judging that a hydraulic hammer impact event caused by thermal runaway occurs in the sealed box body, and positioning an impact area according to the difference of the vibration signals of all sensors in the vibration sensor array; the pressure relief device is used for relieving the pressure of the sealed box body, and the intensified cooling program of the cooling loop is activated. The application designs a set of thermal management system, which is characterized in that a vibration sensor array is arranged on the outer wall of a box body and the signal characteristics of the vibration sensor array are analyzed, then a multistage pressure release channel is utilized for pressure release, and finally, the circulation flow of a cooling loop is simultaneously improved and an intensified cooling medium is introduced, so that the immersed liquid cooling battery energy storage system is helped to truly get rid of thermal runaway and restore to a safe state.

Inventors

ZHAO RONG
ZHOU YUAN
GAN JUNHAO
LIANG FUXIONG

Assignees

湖南西来客储能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The thermal runaway protection method for an immersed liquid-cooled battery energy storage system, the immersed liquid-cooled battery energy storage system comprising a sealed box, a battery module arranged in the sealed box and a cooling loop for circulating insulating cooling liquid, is characterized in that the method comprises the following steps: Monitoring vibration signals on the surface of the box body through a vibration sensor array arranged outside the sealed box body, extracting preset characteristic quantity of the vibration signals, judging that a hydraulic hammer impact event caused by thermal runaway occurs in the sealed box body when the preset characteristic quantity exceeds a preset threshold value, and if the hydraulic hammer impact event is judged to occur, positioning an impact area according to the difference of the vibration signals of all sensors in the vibration sensor array; the pressure relief device is used for relieving pressure of the sealed box body and comprises a plurality of stages of pressure relief channels with different response thresholds, and when the internal pressure of the sealed box body reaches the corresponding response threshold, the pressure relief channels with different stages are sequentially opened; And activating an intensified cooling program of the cooling circuit according to the located impact area, wherein the intensified cooling program comprises the steps of lifting the circulation flow of the cooling circuit and introducing intensified cooling medium into the cooling circuit so as to intensify and cool the located impact area.
2. The method of thermal runaway protection for an immersion liquid cooled battery energy storage system of claim 1, wherein the method of locating an impact region comprises: Performing spectrum analysis on the vibration signal, and extracting signal energy in a preset characteristic frequency band as a preset characteristic quantity; And determining a positioning impact area according to the arrival time difference of the preset characteristic quantity received by the sensors at different positions in the vibration sensor array.
3. The thermal runaway protection method for an immersion liquid cooled battery energy storage system of claim 1, wherein the multi-stage pressure relief channel comprises at least one low pressure pilot channel and at least one high pressure main relief channel; The response threshold corresponding to the low-pressure guide channel is a first-stage pressure threshold, the response threshold corresponding to the high-pressure main relief channel is a second-stage pressure threshold, and the second-stage pressure threshold is larger than the first-stage pressure threshold; When the internal pressure of the sealed box body reaches a first-stage pressure threshold value, opening a low-pressure guide channel; And when the internal pressure of the sealed box body reaches a second-stage pressure threshold value, opening the high-pressure main relief channel.
4. A thermal runaway prevention method for an submerged, liquid-cooled battery energy storage system as claimed in claim 3 wherein the outlet of the low pressure pilot passage is connected to a pilot line for directing the initial gas-liquid mixture flow discharged to a designated area within the sealed enclosure.
5. The method of claim 1, wherein the enhanced cooling medium is a perfluorinated compound having a phase change endothermic characteristic; The method of introducing the enhanced cooling medium into the cooling circuit includes injecting the perfluorinated compounds stored in the separate tank into the cooling circuit to be mixed with the circulated insulating cooling liquid when the enhanced cooling program is activated.
6. The method of claim 1, wherein the method of activating the enhanced cooling procedure of the cooling circuit comprises: increasing the driving power of a circulating pump in the cooling loop to improve the total circulating flow of the system; Valves in the cooling circuit are synchronously regulated to increase the proportion of flow distribution through the branch where the localized impingement region is located.
7. The thermal runaway protection method for an immersion liquid cooled battery energy storage system of claim 1, further comprising the step of cascade fault determination after depressurizing the sealed enclosure by a pressure relief device: And continuously monitoring the feature quantity of the vibration signal after the release and the pressure in the sealed box body, judging that multi-cell interlocking thermal runaway occurs if the feature quantity of the vibration signal and the pressure in the sealed box body do not fall below the corresponding safety threshold value respectively in a preset observation time window, and executing system-level emergency shutdown and fault isolation.
8. The thermal runaway protection method for an immersion liquid cooled battery energy storage system of claim 1, wherein the decision condition for activating the enhanced cooling procedure of the cooling circuit further comprises: the rate of change of the coolant temperature corresponding to the located impingement area is monitored to exceed a change threshold.
9. The thermal runaway protection method for an immersion liquid cooled battery energy storage system of claim 1, wherein the arrangement position of the vibration sensor array is determined based on structural vibration mode analysis of the sealed box body in a characteristic frequency band corresponding to a hydraulic hammer impact event.
10. A thermal runaway protection system for an immersed liquid cooled battery energy storage system for implementing the thermal runaway protection method for an immersed liquid cooled battery energy storage system of any one of claims 1 to 9, the system comprising: The vibration monitoring module comprises a vibration sensor array arranged outside the sealed box body and an analysis unit connected with the vibration sensor array, wherein the analysis unit is configured to execute vibration signal characteristic quantity analysis, preset threshold comparison and impact area positioning; The hierarchical pressure relief module comprises a pressure relief device communicated with the sealed box body, wherein the pressure relief device comprises multi-stage pressure relief channels with different response thresholds; the enhanced cooling control module comprises a driving and valve unit for improving the circulation flow of the cooling loop, an independent storage tank for storing the enhanced cooling medium and an injection unit for connecting the cooling loop and the independent storage tank; the central controller is in communication connection with the vibration monitoring module, the grading pressure relief module and the enhanced cooling control module, and is configured to control the grading pressure relief module to relieve pressure of the sealing box body after judging that a hydraulic hammer impact event occurs in the sealing box body and locating an impact area, and control the enhanced cooling control module to execute an enhanced cooling program according to the located impact area.

Description

Thermal runaway protection method and system for immersed liquid-cooled battery energy storage system Technical Field The invention relates to the technical field of safety of electrochemical energy storage systems, in particular to a thermal runaway protection method and a thermal runaway protection system for an immersed liquid-cooled battery energy storage system. Background With the development of battery energy storage systems, an immersion liquid cooling technology has become a key direction for improving the energy density and the thermal safety of the energy storage systems, and the technology fully submerges battery modules in insulating cooling liquid, and realizes efficient and uniform-temperature heat dissipation through the high specific heat capacity and direct contact of the liquid, so that the temperature difference and hot spot formation between electric cores are obviously inhibited. However, the characteristic of full immersion introduces a physical risk which is easy to be ignored while bringing about extremely high heat dissipation efficiency and fireproof capability, and when a certain cell in the box body is subjected to sudden thermal runaway, a great amount of high-temperature gas generated instantaneously rapidly expands and collapses in nearly incompressible cooling liquid, so that strong transient pressure shock waves are excited, and the phenomenon is also called hydraulic hammer effect caused by local overpressure. The failure mode of thermal runaway is different from slow pressure accumulation, the peak pressure of shock waves caused by the failure mode is extremely high, the propagation is extremely fast, and the safety design of the existing immersed system focuses on thermal management and fire protection, for example, a simple mechanical pressure relief valve or linkage fire protection spray is arranged, and the dynamic hydraulic hammer impact of millisecond to second cannot be effectively identified, buffered or dissipated by passive response measures for static or quasi-static pressure rising and combustion. The resulting shock wave may cause damage to the mechanical structure, failure of the electrical connection, and even fracture of the sealed enclosure adjacent the cell, thereby initiating a series of catastrophic chain reactions. Disclosure of Invention Aiming at the defects in the prior art, the application designs a set of thermal management system, wherein the vibration sensor array is arranged on the outer wall of the box body and the signal characteristics of the vibration sensor array are analyzed, then the multistage pressure release channel is utilized for pressure release, and finally the circulating flow of the cooling loop is simultaneously improved and the reinforced cooling medium is introduced, so that the immersed liquid-cooled battery energy storage system is helped to truly get rid of thermal runaway and restore to a safe state. In order to achieve the above purpose, the present invention provides the following technical solutions: in a first aspect, the invention discloses a thermal runaway protection method for an immersed liquid cooled battery energy storage system comprising a sealed tank, a battery module disposed within the sealed tank, and a cooling circuit for circulating an insulating coolant, the method comprising: Monitoring vibration signals on the surface of the box body through a vibration sensor array arranged outside the sealed box body, extracting preset characteristic quantity of the vibration signals, judging that a hydraulic hammer impact event caused by thermal runaway occurs in the sealed box body when the preset characteristic quantity exceeds a preset threshold value, and if the hydraulic hammer impact event is judged to occur, positioning an impact area according to the difference of the vibration signals of all sensors in the vibration sensor array; the pressure relief device is used for relieving pressure of the sealed box body and comprises a plurality of stages of pressure relief channels with different response thresholds, and when the internal pressure of the sealed box body reaches the corresponding response threshold, the pressure relief channels with different stages are sequentially opened; according to the located impingement area, an enhanced cooling procedure of the cooling circuit is activated, the enhanced cooling procedure comprising elevating a circulation flow of the cooling circuit and introducing an enhanced cooling medium into the cooling circuit. Further, the method of locating the impact zone includes: Performing spectrum analysis on the vibration signal, and extracting signal energy in a preset characteristic frequency band as a preset characteristic quantity; And determining a positioning impact area according to the arrival time difference of the preset characteristic quantity received by the sensors at different positions in the vibration sensor array. Further, the multi-stage pressure relief chann