CN-122025922-A - Liquid-cooled lithium battery pack thermal management system and temperature adjustment method

CN122025922ACN 122025922 ACN122025922 ACN 122025922ACN-122025922-A

Abstract

The invention discloses a liquid cooling type lithium battery pack heat management system and a temperature regulation method, and relates to the technical field of lithium battery heat management, wherein the system comprises a liquid cooling circulation module for forming an insulating fluoride liquid closed circulation; the intelligent control module is based on an industrial embedded controller, calculates and issues a regulating instruction, builds a coordinated linkage heat management framework, provides data support by means of multi-dimensional sensing, optimizes the target phase change temperature of cooling liquid in real time, efficiently interacts with each module to avoid the traditional problem, forms a multi-level heat regulating system, can self-adapt and optimize cooling parameters, and ensures the execution effect of closed loop calibration, strengthens the adaptability and reliability of the system and ensures the operation of the lithium battery pack.

Inventors

QIAN LIJUAN
LI ZHENNAN
ZHU CHENLIN
GUO JINBAO

Assignees

中国计量大学

Dates

Publication Date: 20260512
Application Date: 20260129

Claims (10)

1. A liquid cooled lithium battery pack thermal management system, the system comprising: The liquid cooling circulation module consists of a liquid storage tank, a circulation pump and a condenser, forms an insulating fluorinated liquid closed circulation passage, is integrally linked with the phase-change temperature regulation module and the auxiliary heat dissipation module, and receives an instruction of the intelligent control module to regulate circulation flow; the phase change temperature adjusting module is integrated in the liquid storage tank and consists of a phase change regulator liquid storage bottle, a high-precision metering pump and a mixing cavity, and is used for completing mixing adjustment with the insulating fluoridized liquid, and receiving the adjusting and controlling instruction of the intelligent control module to complete quantitative addition and fine adjustment of the regulator; The multi-dimensional sensing module consists of an environment temperature and humidity sensor and a battery internal resistance on-line monitoring module, acquires data of temperature and humidity, battery internal resistance and change rate outside the lithium battery module, and transmits the data to the intelligent control module through an industrial bus; The detection feedback module is arranged in the liquid storage tank and consists of a phase-change temperature detection probe and a cooling liquid concentration sensor, detects the actual phase-change temperature and the mixed concentration of the cooling medium after adjustment, transmits data to the intelligent control module, and forms closed-loop regulation and control association with the phase-change temperature adjustment module; The auxiliary heat dissipation module is arranged at the outer side of the condenser, the core is a speed-regulating heat dissipation fan, two gears of fixed rotation speeds are arranged, start-stop and rotation speed instructions of the intelligent control module are received, and the auxiliary heat dissipation module is matched with the condenser to finish heat dissipation of a cooling medium; The intelligent control module is used for calculating the target phase change temperature of the cooling medium through a dynamic adaptation algorithm of the phase change temperature of the cooling medium based on the industrial embedded controller, calculating the target circulation flow of the liquid cooling loop through a liquid cooling loop flow collaborative regulation algorithm, realizing electric connection with the liquid cooling circulation module, the phase change temperature regulation module, the multidimensional sensing module, the detection feedback module and the auxiliary heat dissipation module, and issuing corresponding regulation and control instructions to the modules.
2. The liquid cooling type lithium battery pack heat management system according to claim 1 is characterized in that a liquid storage tank of the liquid cooling circulation module is a sealed pressure container, an independent phase change regulator mixing chamber is arranged in the liquid storage tank, a liquid level sensor and a pressure sensor are arranged on the outer wall of the liquid storage tank, the detection end of the sensor stretches into a medium in the tank, the sensor is connected with the intelligent control module through a communication line and transmits monitoring data, the circulation pump is a variable frequency adjustable centrifugal pump, a pump body is integrated with an overcurrent and overheat protection unit, the protection unit is electrically connected with the intelligent control module and sends working condition signals, the condenser is of a shell-and-tube heat exchange structure, heat exchange fins are made of aluminum alloy materials and are subjected to corrosion-resistant coating treatment on the surface, and a temperature sensor is arranged at the medium inlet end of the condenser.
3. The liquid-cooled lithium battery pack thermal management system of claim 1, wherein the phase-change regulator liquid storage bottle of the phase-change temperature regulating module is a light-proof sealed liquid storage container, a liquid level low alarm device is arranged at the bottom of the bottle body, a one-way valve is arranged at a liquid outlet, the metering pump is a micro-flow high-precision plunger pump, a pump body is integrated with a liquid adding quantity accumulation counting unit and is provided with three working modes of quantitative liquid adding, supplementing and fine tuning and emergency stopping, the mixing cavity is a sealed cavity with spiral turbulence blades, the turbulence blades are made of polytetrafluoroethylene materials, a liquid inlet of the mixing cavity is provided with a flow regulating valve, and the liquid outlet is provided with a static mixer.
4. The thermal management system of a liquid-cooled lithium battery pack according to claim 1, wherein the mathematical expression of the dynamic adaptation algorithm of the phase transition temperature of the cooling liquid in the intelligent control module is Wherein, the method comprises the steps of, To cool the liquid dynamic target phase transition temperature, Is a phase change temperature basic value matched with the ambient temperature and humidity, For the internal resistance change rate correction coefficient, Is a normalization factor of the internal resistance change rate of the battery, For the temperature-humidity coupling correction coefficient, The normalization factor is the ambient temperature and humidity coupling.
5. The heat management system of a liquid-cooled lithium battery pack according to claim 1, wherein the mathematical expression of the liquid-cooling loop flow collaborative regulation algorithm built in the intelligent control module is calculated as Wherein, the method comprises the steps of, Q 0 is the basic flow of the liquid cooling loop under the rated working condition of the lithium battery module, Is the feedforward weight coefficient of the internal resistance, Is a normalization factor of the internal resistance change rate of the battery, Is a reference threshold value for the rate of change of the internal resistance of the battery, The weight coefficient is fed back for the phase transition temperature deviation, Is a normalized factor of the phase transition temperature deviation, Is the weight coefficient of the heat exchange gain of the humidity, Is an ambient humidity heat exchange gain factor.
6. A method for regulating the temperature of a liquid-cooled lithium battery thermal management system, the method being applied to a liquid-cooled lithium battery thermal management system according to any one of claims 1 to 5, the method comprising the steps of: S100, parameter pre-configuration, namely presetting a system regulation rule, a threshold parameter and an algorithm coefficient in a controller, and finishing calibration and storage of a thermal regulation reference parameter; S200, data acquisition, namely continuously acquiring the temperature and humidity of the external environment of the lithium battery module, the internal resistance of the battery and the change rate data through a multidimensional sensing module, and synchronously transmitting all acquired data to a controller; s300, parameter calculation, namely preprocessing data after the controller receives the acquired data, calculating a target phase change temperature of the cooling liquid through a dynamic adaptation algorithm of the phase change temperature of the cooling liquid, calculating a target flow of the liquid cooling loop through a flow collaborative regulation algorithm of the liquid cooling loop, and integrating the target phase change temperature of the cooling liquid and the target flow of the liquid cooling loop to form a cooling parameter regulation scheme; S400, regulating and calibrating, namely, the controller issues regulating and controlling instructions to each execution module according to a cooling parameter regulating and controlling scheme to finish phase-change temperature regulation, auxiliary heat dissipation regulation and emergency flow regulation, and the actual phase-change temperature and mixed concentration data monitored by the detection feedback module are combined to perform closed-loop calibration and correction on the phase-change temperature of the cooling liquid and the flow of the liquid cooling loop; S500, dynamically adapting, namely continuously acquiring real-time data by the multidimensional sensing module and the detection feedback module and transmitting the real-time data to the controller, continuously updating the target phase-change temperature of the cooling liquid and the target flow of the liquid cooling loop by the controller according to data fluctuation through a dynamic phase-change temperature adapting algorithm of the cooling liquid and a flow cooperative regulating and controlling algorithm of the liquid cooling loop, repeatedly executing the operation of regulating and controlling calibration, and completing dynamic self-adapting regulation and control of cooling parameters.
7. The method for temperature regulation of a liquid-cooled lithium battery pack thermal management system according to claim 6, wherein in step S100, the preset system regulation rule in the controller includes a rule for matching an ambient temperature and a cooling liquid phase temperature change basic value, the cooling liquid phase temperature change basic value is 25 ℃ when the ambient temperature is from-20 ℃ to 10 ℃, the cooling liquid phase temperature change basic value is 30 ℃ when the ambient temperature is from 10 ℃ to 25 ℃, the cooling liquid phase temperature change basic value is 35 ℃ when the ambient temperature is from 25 ℃ to 40 ℃, the cooling liquid phase temperature change basic value is 40 ℃ when the ambient temperature is from 40 ℃ to 60 ℃, the preset threshold parameter includes a temperature and humidity mutation judgment threshold, a phase change temperature deviation regulation threshold, a battery internal resistance change rate threshold, the temperature and humidity mutation judgment threshold is an ambient temperature change rate critical value, the phase change temperature deviation regulation threshold is an allowable deviation value between an actual cooling liquid phase temperature value and a target value, the battery internal resistance change rate threshold is a critical value changing in unit time when the ambient temperature is from 10 ℃ to 25 ℃, the preset correction algorithm includes a humidity change factor correction algorithm, a humidity change factor correction weight factor, a calibration factor is stored in the memory module, and a calibration factor is calibrated after all the temperature change factor is stored in the memory, and the temperature regulation control module is calibrated by the parameter.
8. The method for temperature regulation of a liquid-cooled lithium battery pack thermal management system according to claim 6, wherein in step S200, the multi-dimensional sensing module collects the current ambient temperature outside the lithium battery module, the ambient temperature before one hour, and the real-time ambient relative humidity each time, the battery internal resistance on-line monitoring module collects the current internal resistance of the lithium battery, the internal resistance before one hour, and calculates the internal resistance change rate, the multi-dimensional sensing module synchronously transmits all collected data to the controller through the industrial bus, a data frame checking mechanism is adopted in the transmission process, the controller performs time stamp marking on all the received collected data, the data is stored in a cache unit of the controller according to the collection time sequence, the cache unit is a component of the intelligent control module, the cache unit stores the collected data according to a preset rule, and the preset rule sequentially covers historical collected data exceeding the storage capacity.
9. The method for adjusting the temperature of a liquid-cooled lithium battery pack thermal management system according to claim 6, wherein in the step S300, the operation of preprocessing the collected data by the controller includes removing abnormal collected data exceeding 3 sigma principle, replacing the abnormal collected data with effective collected data of a previous collection period, calculating a target phase-change temperature of the cooling liquid through a dynamic adaptation algorithm of the phase-change temperature of the cooling liquid after preprocessing is completed, limiting the value rule of the target phase-change temperature of the cooling liquid to a range from 25 ℃ to 40 ℃, calculating a target flow of the liquid-cooled circuit through a cooperative regulation algorithm of the flow of the liquid-cooled circuit, limiting the value rule of the target flow of the liquid-cooled circuit to 1.2 times of the basic flow of the liquid-cooled circuit under the rated working condition of the lithium battery module, limiting the upper limit to 2.0 times of the basic flow of the liquid-cooled circuit under the rated working condition of the lithium battery module, executing the target flow of the liquid-cooled circuit according to a lower limit value when the change rate of the ambient temperature and the change rate of the ambient relative humidity in the collected data reach a mutation judgment threshold, and integrating the target temperature of the cooling liquid and the target flow of the liquid cooled circuit as the cooling parameter.
10. The method for temperature regulation of a liquid-cooled lithium battery pack thermal management system according to claim 6, wherein in step S400, the controller issues a regulation command to the phase-change temperature regulation module, the liquid cooling circulation module and the auxiliary heat dissipation module according to a cooling parameter regulation scheme, the regulation command issued to the phase-change temperature regulation module comprises a liquid adding amount, a liquid adding rate and a liquid adding interval, the judgment rule of closed loop calibration is that when the deviation between the actual phase-change temperature value of the cooling liquid collected by the detection feedback module and the target phase-change temperature of the cooling liquid reaches a phase-change temperature deviation regulation threshold value, the controller issues a command for adding a regulator to the phase-change temperature regulation module, the regulation command issued to the auxiliary heat dissipation module comprises a fan start-stop state and a fan rotating speed, the speed regulation rule of the speed regulation type heat dissipation fan of the auxiliary heat dissipation module is that the fan is closed when the ambient relative humidity is lower than 60%, the fan rotating speed is 1000 revolutions per minute when the ambient relative humidity is between 60% and 80%, the fan rotating speed is 1500% or more, and the emergency flow regulation rule issued to the liquid cooling circulation module is that the ambient temperature change rate and the ambient temperature change rate reaches the threshold value when the ambient relative humidity change rate reaches the threshold value.

Description

Liquid-cooled lithium battery pack thermal management system and temperature adjustment method Technical Field The invention relates to the technical field of lithium battery thermal management, in particular to a liquid-cooled lithium battery pack thermal management system and a temperature regulation method. Background With the rapid development of new energy industry, the lithium battery has become the core power source of various new energy devices by virtue of the core advantages of high energy density, long cycle life, low pollution discharge and the like, and is widely applied to a plurality of important fields, the operation performance and the service life of the lithium battery directly depend on the working temperature environment of the lithium battery, the temperature deviation from a proper interval can lead to rapid attenuation of the battery capacity and abnormal increase of internal resistance, and the safety risks such as thermal runaway and the like can be caused when the temperature deviation is serious, so that the thermal management system becomes an indispensable key supporting facility in the application of the lithium battery, and compared with the traditional air cooling technology, the liquid-cooled thermal management system has the remarkable advantages of high heat exchange efficiency, good temperature control uniformity, low space occupancy rate and the like, and gradually becomes the main flow thermal management scheme of a medium-high power lithium battery pack, however, the operation environment of the lithium battery is more complex with the continuous expansion of application scenes, the working condition fluctuation is more and more frequent, the requirements on the dynamic adaptation capability, the accurate regulation level and the comprehensive reliability of the thermal management system are provided, the comprehensive requirements on the key parameters of the battery operation state and environment parameters of the battery are required to be comprehensively perceived, and the requirements on the key states and the environment parameters of the cooling system are met, and the requirements of the lithium battery can stably operate under different conditions. The traditional liquid cooling type lithium battery pack thermal management system has a plurality of limitations which are difficult to overcome, cannot fully adapt to complex and changeable practical application requirements, most traditional systems only take single temperature data as a regulation basis, ignore key influencing factors such as battery internal resistance change, environment temperature and humidity coupling effect and the like, lead to lack of comprehensiveness and scientificity of regulation and control decisions, often keep constant phase change characteristics of cooling media, cannot be dynamically regulated according to changes of battery working conditions and environment conditions, enable deviation of cooling effects and practical requirements to exist, and the flow regulation of a liquid cooling loop is mainly controlled independently, does not form a cooperative regulation mechanism with the phase change temperature of the cooling media, is easy to cause the problem of insufficient heat dissipation or overhigh energy consumption, meanwhile, the sensing dimension of the traditional systems is relatively single, accurate monitoring of key state parameters such as the concentration of the cooling media, the phase change temperature and the like is not complete, the regulation and control deviation is difficult to be found and corrected in time, hysteresis of temperature control exists, the environment mutation or the battery state cannot be rapidly responded, the battery ageing can be accelerated during long-term operation, and the reliability and safety of the whole system are reduced. Disclosure of Invention The invention aims to make up the defects of the prior art, and provides a liquid cooling type lithium battery pack thermal management system and a temperature regulation method, which integrate liquid cooling circulation, phase transition temperature regulation, multidimensional sensing, detection feedback, auxiliary heat dissipation and intelligent control modules, build a collaborative linkage framework, carry two types of core algorithms on the intelligent control modules, dynamically calculate the target phase transition temperature of cooling liquid and the target flow of a liquid cooling loop by combining data such as environmental temperature and humidity, internal resistance of a battery and the like acquired by multidimensional sensing, and realize accurate optimization and real-time adjustment of cooling parameters through complete flows of parameter pre-configuration, data acquisition, calculation regulation, closed loop calibration and dynamic adaptation, ensure that the lithium battery pack is in a proper temperature range due to high effect on working conditions and