Battery thermal management method and system based on new energy agricultural machinery

Abstract

The application discloses a battery thermal management method and system based on new energy agricultural machinery, relates to the technical field of new energy agricultural machinery, and comprises the following steps: S001, an energy backflow cooling flow direction synchronous perception chain is constructed, the cooling liquid flow direction change is detected in real time, the dynamic characteristics of the cooling liquid flow direction turning moment is captured, the flow direction reversal starting point is calibrated, and the reversal anchor point is generated; S002, a cooling flow field and a thermal flow conduction phase difference distribution model are established with the reversal anchor point as the center, the difference value of the cooling flow phase and the thermal conduction phase is calculated, a phase difference distribution diagram is formed, and a phase error layer area is identified and a temperature oscillation source is determined. Through the construction of the cooling flow direction synchronous perception chain and the phase difference distribution model, the application realizes the dynamic coordination of the flow direction and the thermal conduction, improves the temperature distribution uniformity; through the setting of the temperature back-rolling bypass, the pump speed phase traction sequence and the thermal balance scheduling window, the cooling liquid flow direction change is stable and controllable, the battery system temperature difference is maintained stable, and the efficient and safe operation of the battery system is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy agricultural machinery, in particular to a battery thermal management method and system based on new energy agricultural machinery. BACKGROUND

[0002] The battery thermal management based on new energy agricultural machinery refers to establishing a dynamic monitoring and active control thermal management mechanism for lithium ion batteries of agricultural machinery equipment (such as electric tractors, electric harvesters, electric plant protection machines, etc.) with electric energy as the main power source, which is prone to be affected by factors such as external environment temperature, operation load, and charging and discharging intensity under different operation environments. The mechanism collects the temperature distribution of lithium ion battery monomers and groups, environmental temperature, and power consumption information in real time, judges whether the battery is in an overheating or overcooling state, and executes cooling, heating, or thermal balance scheduling strategies accordingly. Through liquid cooling, air cooling, phase change material heat absorption, heat pump circulation, and other means, the lithium ion battery temperature is balanced and controlled to keep it within an appropriate working temperature range, thereby improving the battery energy utilization level, prolonging the service life, and reducing the risk of thermal runaway, ensuring the safe and stable operation of new energy agricultural machinery under high load, long time, and complex climate conditions.

[0003] The prior art has the following disadvantages:

[0004] In the prior art, when the new energy agricultural machinery is in the recovery braking stage of descending slope, the drive system will change from energy output state to energy return state, and the motor will convert mechanical energy into electric energy to charge the battery. Due to the sudden change in energy flow direction, the cooling liquid flow direction in the thermal management system is prone to reverse in a short time, and the response of the control strategy lags behind, so that the cooling flow field and the heating flow field still in the heat dissipation state are superimposed in space. During this superimposition process, the reverse pulsation of the cooling flow field and the heat flow conduction phase of the cell heat dissipation path resonate, causing periodic oscillation in the temperature field. Temperature oscillation can cause uneven heat distribution between cells, destroy the thermal balance structure, cause local overheating or overcooling, and easily lead to cell performance degradation, unstable battery pack energy output, and even thermal runaway risk after long-term operation, seriously affecting the safety and reliability of new energy agricultural machinery under complex slope operation conditions.

[0005] The above information disclosed in the background section is only used to enhance the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a battery thermal management method and system based on new energy agricultural machinery to solve the problems in the background.

[0007] In order to achieve the above object, the present application provides the following technical scheme: a battery thermal management method based on new energy agricultural machinery, comprising the following steps:

[0008] S001, a synchronous sensing chain of energy backflow cooling flow direction is constructed, the change of cooling liquid flow direction is detected in real time, the dynamic characteristics of the moment of cooling liquid flow direction reversal are captured, the starting point of flow direction reversal is calibrated, and a reversal anchor point is generated;

[0009] S002, a phase difference distribution model of cooling flow field and heat flow conduction is established with the reversal anchor point as the center, the difference between the cooling flow phase and the heat conduction phase is calculated, a phase difference distribution map is formed, a phase error layer area is identified, and a temperature shock source is determined;

[0010] S003, reverse guide channels are constructed on both sides of the phase error layer area, a temperature roll-back bypass is formed through the guide channels, an energy back-feeding path is limited to buffer the reverse impact of the cooling flow field;

[0011] S004, a pump speed phase traction sequence is established based on the tail end of the temperature roll-back bypass, segmented flow direction switching is performed according to the time rhythm of the reversal anchor point, the cooling liquid flow direction change rate is controlled to reduce the reverse superposition effect;

[0012] S005, a thermal equilibrium scheduling window is set at the tail end of the pump speed phase traction sequence, the position of the reversal anchor point is adjusted and the cooling flow direction weight is compressed under the time rhythm, the stability of the battery temperature distribution is maintained through time sequence scheduling, and the thermal equilibrium state of the battery system is maintained.

[0013] Preferably, step S001 comprises:

[0014] A plurality of flow direction detection units are arranged in the key flow path of the cooling liquid circulation loop, the flow direction, flow rate and flow pressure of the cooling liquid in the energy output stage are continuously collected through the flow detection sensor assembly, and a continuous flow state data stream is formed;

[0015] After completing the flow state data collection, the initial signs of cooling liquid flow direction reversal are identified based on the time comparison results of the cooling liquid flow rate vector and the pressure gradient, and the trend change process of the cooling liquid flow direction reversal is extracted;

[0016] After identifying the trend change of the cooling liquid flow direction reversal, the changes of the cooling liquid flow rate, pressure and temperature are continuously tracked, the transition process of the cooling liquid from forward flow to reverse flow is captured, and the critical moment of flow direction reversal is calibrated;

[0017] After completing the capture of the critical moment of flow direction reversal, the starting point of flow direction reversal is calibrated and a reversal anchor point is generated according to the combined characteristics of the cooling liquid flow direction, pressure and temperature, which is used as a reference time signal for subsequent thermal management control.

[0018] Preferably, step S002 comprises:

[0019] After the calibration of the reverse anchor point of the cooling liquid flow is completed, the time node and the spatial position corresponding to the reverse anchor point are taken as the reference to collect the cooling liquid flow rate, pressure and temperature change data, and the basic distribution framework of the cooling flow field is established;

[0020] After the basic distribution framework of the cooling flow field is established, a plurality of equidistant sampling points are divided along the length direction of the cooling channel, the cooling liquid flow state and the heat conduction state are spatially mapped, and the difference between the cooling flow phase and the heat conduction phase is calculated;

[0021] After the difference between the cooling flow phase and the heat conduction phase is obtained, the phase difference distribution map is formed with the reverse anchor point as the center, and the phase mismatch layer area between the cooling flow field and the heat conduction is depicted in the distribution map;

[0022] After the phase difference distribution map is formed, the phase gradient change of the phase mismatch layer area is identified, the area with the largest phase shift between the cooling flow phase and the heat conduction phase is determined, and the center point of the area is determined as the temperature oscillation source.

[0023] Preferably, the determination of the temperature oscillation source is based on the position with the largest phase gradient change in the phase difference distribution map, and is confirmed in combination with the spatial intersection area of the cooling liquid flow direction and the heat conduction direction.

[0024] Preferably, step S003 comprises:

[0025] After the phase mismatch layer area is identified, the area with uneven heat flow distribution in the cooling liquid flow field is determined with the center axis of the phase mismatch layer area as the symmetrical reference, and the guide channel reserved area is set on both sides of the boundary of the phase mismatch layer area;

[0026] After the guide channel reserved area is set, the reverse guide channel parallel to the main cooling channel is established along the outer edge of the phase mismatch layer area, so that the cooling liquid enters the reverse guide channel to form the backflow when the flow direction is reversed;

[0027] After the reverse guide channel is established, the temperature backflow bypass is formed through the intersection structure of the reverse guide channel and the main cooling channel, so that the heat in the cooling liquid is backflowed and transferred on both sides of the phase mismatch layer area;

[0028] After the temperature backflow bypass is formed, the energy backflow path is limited based on the multi-point connection of the reverse guide channel and the main cooling channel, so that the flow trajectory of the cooling liquid in the energy backflow stage is controlled and distributed to buffer the reverse impact of the cooling flow field.

[0029] Preferably, the inner wall of the reverse guide channel is made of the same heat conduction material as the main cooling channel, so as to keep the temperature change process of the cooling liquid in the guide channel smooth and prevent local overheating area.

[0030] Preferably, step S004 comprises:

[0031] A pump speed regulation response node is arranged at the fluid confluence area at the tail end of the temperature rollback bypass, and the changes in the flow rate, pressure and temperature of the cooling liquid are collected to form a reference basis for pump speed regulation;

[0032] After the pump speed regulation response node is set, a pump speed phase traction sequence is constructed based on the time reference of the reverse anchor point, the change in the pump speed is divided into multiple phase intervals, and the pump speed change is kept in correspondence with the change in the flow direction of the cooling liquid;

[0033] After the pump speed phase traction sequence is formed, the segmented flow direction switching is performed according to the time rhythm of the reverse anchor point, and the cooling liquid gradually completes the flow direction transition between the temperature rollback bypass and the main cooling channel;

[0034] After the segmented flow direction switching is completed, the tail section of the pump speed phase traction sequence is adjusted to control the change rate of the flow direction of the cooling liquid, so that the momentum change of the cooling liquid in the reverse flow stage is gentle, thereby reducing the reverse superposition effect of the cooling flow field.

[0035] Preferably, the pump speed regulation response node is arranged at a position upstream of the intersection area of the temperature rollback bypass and the main cooling channel, and the change amplitude of the pump speed is dynamically adjusted according to the temperature change trend of the cooling liquid, so that the cooling liquid completes kinetic energy buffering and heat distribution before entering the main cooling channel.

[0036] Preferably, step S005 comprises:

[0037] The time boundary of the thermal equilibrium scheduling window is established at the tail end of the pump speed phase traction sequence, so that the thermal equilibrium scheduling window corresponds to the time interval in which the cooling liquid completes the segmented flow direction switching and enters the stable backflow stage;

[0038] After the thermal equilibrium scheduling window is opened, the position of the reverse anchor point is dynamically adjusted based on the time rhythm, so that the temperature distribution of the cooling liquid changes around the reverse anchor point in different rhythm periods;

[0039] After the position adjustment of the reverse anchor point is completed, the flow direction weight is compressed, so that the flow proportion of the cooling liquid in different flow direction stages forms a gradual distribution;

[0040] After the flow direction weight compression is completed, the flow state of the cooling liquid is regulated through timing scheduling, so that the temperature distribution of the electric core remains stable, thereby maintaining the thermal equilibrium state of the battery system.

[0041] The battery thermal management system based on the new energy agricultural machine comprises a flow direction sensing module, a phase analysis module, a guide bypass module, a flow direction control module and a thermal equilibrium scheduling module:

[0042] A flow direction sensing module is configured to build a cooling flow direction synchronous sensing chain, to detect the change in the cooling liquid flow direction in real time, to capture the dynamic characteristics of the cooling liquid flow direction reversal moment, to mark the reversal starting point and to generate a reversal anchor point.

[0043] A phase analysis module is configured to build a cooling flow field and heat flow conduction phase difference distribution model with the reversal anchor point as the center, to calculate the difference between the cooling flow phase and the heat conduction phase, to form a phase difference distribution map, to identify the phase misalignment area and to determine the temperature oscillation source.

[0044] A guide bypass module is configured to build a reverse guide channel on both sides of the phase misalignment area, to form a temperature roll-back bypass through the guide channel, to limit the energy injection path to buffer the reverse impact of the cooling flow field.

[0045] A flow direction control module is configured to build a pump speed phase traction sequence based on the tail end of the temperature roll-back bypass, to perform segmented flow direction switching according to the time rhythm of the reversal anchor point, to control the cooling liquid flow direction change rate to reduce the reverse superposition effect.

[0046] A thermal balance scheduling module is configured to set a thermal balance scheduling window at the tail end of the pump speed phase traction sequence, to adjust the position of the reversal anchor point and to compress the cooling flow direction weight under the time rhythm, to maintain the stability of the battery cell temperature distribution through time sequence scheduling, and to maintain the thermal balance state of the battery system.

[0047] In the above technical solution, the present application provides technical effects and advantages:

[0048] The present application builds a cooling flow direction synchronous sensing chain and a phase difference distribution model in the energy return stage, so that the dynamic relationship between the cooling liquid flow direction change and the heat conduction path can be grasped in real time. When the flow direction reverses, the time and space state of the cooling liquid flow can be captured and adjusted synchronously based on the reversal anchor point, so as to avoid the superposition phenomenon of the cooling flow field and the heat flow conduction field in the transition stage. Through accurate marking of the reversal starting point, the heat flow transfer remains continuous during direction conversion, significantly improves the uniformity of the temperature distribution, suppresses the periodic fluctuation of heat in the battery cell, and improves the thermal response stability of the battery pack.

[0049] The present application builds a temperature roll-back bypass and a pump speed phase traction sequence, so that the cooling liquid flow has a buffering and rhythm regulation function in the reversal process. The flow direction change changes from mutation to gradual change, the pump speed adjustment is consistent with the rhythm of the reversal anchor point, and the kinetic energy of the cooling liquid and the heat distribution are gradually balanced. The thermal balance scheduling window realizes dynamic thermal scheduling under the time rhythm, so that the temperature difference between the battery cells is kept within a stable range, avoiding local overheating or overcooling caused by flow field impact, thereby improving the operation safety and service life of the battery system under complex operating conditions. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed in the embodiments will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only represent some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0051] Figure 1 The method flowchart of the battery thermal management method based on new energy agricultural machinery of the present application.

[0052] Figure 2 The module schematic diagram of the battery thermal management system based on new energy agricultural machinery of the present application. DETAILED DESCRIPTION

[0053] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these example implementations are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art.

[0054] The present application provides a battery thermal management method based on new energy agricultural machinery as shown in Figure 1 The battery thermal management method based on new energy agricultural machinery of the present application comprises the following steps:

[0055] S001, an energy backflow cooling flow direction synchronous sensing chain is constructed, real-time detection of cooling liquid flow direction change is performed, dynamic characteristics of cooling liquid flow direction reversal moment are captured, a flow direction reversal starting point is calibrated, and a reversal anchor point is generated;

[0056] In order to realize accurate perception and synchronous response of new energy agricultural machinery to cooling liquid flow direction in the energy backflow stage, an energy backflow cooling flow direction synchronous sensing chain can be constructed to monitor and calibrate the transient change of cooling liquid from forward flow to reverse flow in the recycling braking process in real time, thereby providing basic data support for subsequent flow field control and temperature regulation. The specific implementation steps are as follows:

[0057] A plurality of flow direction detection units are arranged in the key flow path of the cooling liquid circulation loop, the flow direction, flow speed, flow pressure and other physical characteristics of the cooling liquid under normal driving conditions are continuously collected by the flow detection sensor assembly arranged between the flow inlet and the flow outlet, to form a continuous flow state data stream. At this time, the flow direction detection unit and the temperature acquisition unit work cooperatively to ensure that the flow reference state of the cooling liquid in the energy output stage is completely recorded. By continuously collecting the flow direction change curve under different conditions, a stable reference baseline can be provided for subsequent flow direction mutation identification. The focus of this stage is to establish a complete sequence of cooling liquid flow characteristics, so that the sensing chain has a pre-response capability to flow direction change before the energy backflow condition arrives.

[0058] After the completion of the baseline state acquisition, the perception chain enters the energy backflow trigger response stage. When the new energy agricultural machinery is in the energy recovery working condition such as downhill, the driving motor starts to convert mechanical energy into electrical energy to inject into the battery pack, at this time the cooling liquid flow direction changes trend. In order to accurately capture this trend change, the flow direction detection unit compares the flow velocity vector and the pressure gradient in time series, and monitors the gradual transition process of the cooling liquid flow direction. At the same time, the inertial flow of the cooling liquid in the circuit will cause a short-term lag phenomenon, and the perception chain identifies the time delay of the flow direction change, and matches the time node of the energy backflow start with the time node of the cooling liquid direction change, so as to extract the initial sign of the cooling liquid flow direction reversal. When the flow direction vector direction changes in the opposite direction in the continuous time, it is determined that the flow direction reversal is in the early stage, and the perception chain enters the dynamic feature capture process.

[0059] After detecting the initial trend of flow direction reversal, the perception chain captures the instantaneous features of the cooling liquid flow direction reversal with high precision. This process refines the transition stage of the cooling liquid flow direction from positive inflow to reverse outflow by continuously tracking the flow velocity change curve, pressure change gradient and temperature fluctuation amplitude. The cooling liquid is affected by inertial force and pressure difference in the circuit, and may appear local reverse vortex area and flow wave crest in a short time. The perception chain identifies the time sequence of these flow wave crests to determine the critical moment when the cooling liquid completes the direction reversal. This critical moment is the key node of the flow direction reversal in the energy backflow stage, and the corresponding time point and the flow direction vector direction change point together constitute the preliminary calibration basis of the flow direction reversal starting point. In this process, the momentum change and temperature gradient change of the cooling liquid are used as reference parameters to accurately lock the time window of the cooling liquid flow direction reversal, so that the critical moment of the cooling liquid flow direction change is recorded synchronously.

[0060] After the flow direction reversal critical moment is captured, the perception chain completes the calibration of the flow direction reversal starting point and generates the reversal anchor point according to the joint features of flow direction, pressure and temperature. The reversal anchor point is used as the reference control signal of the energy backflow stage to identify the accurate time position of the transition of the cooling liquid from positive flow state to reverse flow state. The reversal anchor point not only records the starting point information of the cooling liquid flow direction reversal, but also synchronously contains the multi-dimensional physical parameters such as flow velocity, flow pressure and cooling liquid temperature at this moment, to describe the dynamic state characteristics at the time of flow direction reversal. By embedding the reversal anchor point into the subsequent flow field regulation process, the subsequent temperature equalization regulation link can respond dynamically around the anchor point. The generation of the reversal anchor point completes the whole process from cooling liquid flow direction perception to time calibration, so that the whole process of cooling liquid flow direction change has the basic conditions of traceability, response and quantification.

[0061] S002, a phase difference distribution model of cooling flow field and heat conduction is established based on the reverse anchor point as the center, the difference between cooling flow phase and heat conduction phase is calculated, a phase difference distribution map is formed, a phase error layer area is identified, and a temperature shock source is determined;

[0062] In order to accurately grasp the coupling relationship between the cooling flow state and the thermal conduction state of the new energy agricultural machine in the energy reflux stage, and identify the phase error layer between the flow field and the thermal field, a phase difference distribution model of cooling flow field and heat conduction can be established based on the reverse anchor point as the time and space reference center. The specific implementation steps are as follows:

[0063] After completing the calibration of the cooling liquid flow direction reverse anchor point, the time node and space position corresponding to the reverse anchor point are taken as the synchronous reference point of the cooling flow state and the thermal conduction state, and the basic distribution framework of the cooling flow field is established. By setting flow parameter acquisition units on the key flow paths inside the battery pack cooling channel, the flow velocity vector direction, flow pressure gradient and temperature gradient change of the cooling liquid are continuously collected to form the flow state distribution of the period before and after the reverse anchor point. The focus of this stage is to capture the flow pattern of the cooling liquid at each instant in the transition area from forward to reverse flow based on the reverse anchor point, and then to depict the evolution trajectory of the cooling liquid flow direction in space. At the same time, the thermal conduction path inside the cooling channel is recorded synchronously to ensure that a one-to-one mapping relationship is established between the spatial distribution of heat conduction and the cooling liquid flow path. Through this synchronous collection based on the reverse anchor point as the core, the time-space relationship of cooling flow and heat conduction can be obtained under the same reference coordinate, providing a continuous data basis for subsequent phase difference analysis.

[0064] After establishing the time-space mapping of cooling flow and heat conduction, a phase difference distribution model of cooling flow field and heat conduction is constructed based on the reverse anchor point as the center. This process divides multiple equidistant sampling points in the length direction of the cooling channel, and synchronously calibrates the cooling liquid flow velocity change direction and the heat conduction direction at each sampling point to determine the corresponding relationship between the cooling liquid flow and the heat conduction in the spatial distribution. When the cooling liquid flow direction is reversed, the fluid particles at different positions will produce time delay effect, making the flow phase present a lag distribution in space; while the heat inside the battery cell propagates along the heat conduction path, due to the relatively slow heat conduction rate, the heat conduction phase lags behind the flow phase. By establishing the spatial mapping of cooling flow phase and heat conduction phase on both sides of the reverse anchor point, the relative phase difference between the two can be obtained. This phase difference reflects the degree of asynchronization between the cooling flow field and the heat conduction path during the cooling liquid flow direction reversal process, providing a quantitative basis for identifying the heat-flow error layer.

[0065] After obtaining the difference between the cooling flow phase and the heat conduction phase, a phase difference distribution map is formed with the reversed anchor point as the center. The distribution map takes spatial coordinates as the horizontal axis and time series as the vertical axis, and depicts the phase difference of different regions in the cooling flow field in a continuous layered manner, thereby presenting the offset between the cooling fluid flow and the heat conduction in the time and space dimensions. When the flow direction of the cooling fluid in a certain region periodically deviates from the heat flow conduction direction, regularly distributed staggered bands will appear in the phase difference distribution map. Through the density, width and change trend of these staggered bands, the degree of energy transfer asynchronization between the cooling fluid and the heat conduction path can be intuitively reflected. Especially in the cooling channel near the reversed anchor point, if the phase difference periodically fluctuates, it means that the cooling flow direction reverses and interferes with the heat conduction direction in a short time, which may cause temperature oscillation. At this stage, the phase difference distribution map not only plays a role in visualizing the cooling flow field and the heat conduction field, but also provides a spatial indication for identifying the temperature oscillation source.

[0066] After the phase difference distribution map is established, the region where the phase staggered layer appears in the distribution map is identified and located to determine the temperature oscillation source. By analyzing the phase gradient change on both sides of the phase staggered layer region, the region where the phase difference between the cooling fluid flow and the heat conduction is the largest can be determined, and the center point of this region is the core position of the temperature oscillation source. This temperature oscillation source reflects the uneven coupling region between the energy transfer path of the cooling fluid flow and the heat conduction path after the flow direction of the cooling fluid reverses, and its existence causes the periodic fluctuation of heat in the spatial distribution. Corresponding to the heat flow conduction direction of the temperature oscillation source and the adjacent region with the reversed anchor point as the center, the diffusion range and duration of the temperature oscillation source can be further confirmed, thereby providing accurate spatial reference for subsequent cooling flow field guidance and heat balance regulation. By identifying the position and boundary of the temperature oscillation source, a guide channel can be constructed in the subsequent step with the region as the center, realizing the redistribution of the cooling fluid flow direction and the optimization of the energy return path.

[0067] S003, reverse guide channels are constructed on both sides of the phase staggered layer region to form temperature roll-back bypasses, and the energy return path is limited to buffer the reverse impact of the cooling flow field;

[0068] To slow down the fluid impact of the cooling flow field after the flow direction reverses in the energy return stage, and to suppress the uneven heat transfer caused by the sudden change of the cooling fluid direction, reverse guide channels can be constructed on both sides of the identified phase staggered layer region to form temperature roll-back bypasses, thereby limiting the energy return path and buffering the reverse impact of the cooling flow field. The specific implementation process is as follows:

[0069] After the phase slip layer region is identified, the center axis of the phase slip layer region is taken as the symmetric reference to determine the uneven area of the heat flow distribution in the cooling liquid flow field. On both sides of the phase slip layer region, there are usually areas where the cooling liquid flow direction and the heat flow conduction direction are opposite. At the boundary between these areas, the cooling liquid flow rate gradient and the temperature gradient change most obviously, forming an energy transfer discontinuous band. In order to enable energy to transition in a controlled manner within the discontinuous band, a guide channel reservation area is set up on both sides of the boundary of the phase slip layer region. The reservation area is selected in a section with a high frequency of cooling liquid flow direction conversion, so that the cooling liquid can enter the stable flow area through the guide channel after the flow direction is reversed. The focus of this stage is to determine the starting position, flow direction, and connection mode with the main cooling channel of the guide channel according to the spatial distribution structure of the phase slip layer region, thereby forming the geometric basis for constructing the reverse guide channel.

[0070] After the guide channel reservation area is determined, the reverse guide channel is established along the outer edge of the phase slip layer region according to the dynamic characteristics of the energy backflow in the cooling liquid flow field. The reverse guide channel is formed by an auxiliary flow path parallel to the main cooling channel, and its flow direction is opposite to the energy backflow direction, forming a local backflow fluid channel structure. When the cooling liquid in the main channel changes the flow direction, part of the cooling liquid is introduced into the reverse guide channel, forming a local annular flow inside the channel. The annular flow forms a backflow effect through the spatial curvature and flow rate difference, so that the cooling liquid completes energy exchange and momentum decay in the guide channel before entering the main channel in the reverse direction, thereby reducing the fluid impact strength inside the main channel. At the same time, the material thermal conductivity of the inner wall of the reverse guide channel is consistent with that of the main cooling channel, to ensure that the temperature change process of the cooling liquid in the guide channel can be smoothly transitioned, without producing new local overheating areas. The role of this step is to build a physical flow path for the cooling liquid to obtain an intermediate path with energy buffering and heat balance characteristics during the energy backflow stage.

[0071] After the reverse guiding channels are formed, a temperature backflow bypass is established on both sides of the phase slip layer area through the channels. The temperature backflow bypass is formed by the intersection of the two reverse guiding channels and the middle part of the main cooling channel. During the flow of the cooling liquid in the reverse guiding channels, part of the heat is returned to the lower temperature area of the main cooling channel through conduction and convection, thereby forming a circular heat backflow path. The temperature backflow bypass can make the cooling liquid transfer the residual heat in the hot area to the lower temperature area through the bypass in the initial stage of reverse flow in the main channel, achieving energy redistribution. Through the establishment of the temperature backflow bypass, the heat distribution of the cooling liquid flow in the phase slip layer area changes from a concentrated state to a diffuse state, and the area where the temperature peak is prone to occur is effectively buffered. At the same time, the temperature backflow bypass forms an energy buffer ring in fluid dynamics, which gradually reduces the pressure difference between the reverse guiding channel and the main channel, thereby weakening the inertial impact force of the cooling liquid in the reverse stage. This process ensures that the flow kinetic energy of the cooling liquid after the flow direction is reversed tends to be stable in spatial distribution, reducing the temperature fluctuation amplitude.

[0072] After the temperature backflow bypass is established, an energy injection path is defined based on the bypass to control the flow trajectory of the cooling liquid in the energy return stage. The energy injection path is formed by the multi-point connection of the reverse guiding channel and the main cooling channel. When the motor enters the energy recovery state, the cooling liquid gradually transitions from backflow in the guiding channel to reverse flow in the main channel. This process, through path definition, allows the energy in the cooling liquid to gradually conduct from the heat-intensive area to the lower temperature energy absorption area, achieving energy redistribution in the flow space. Through the definition of the energy injection path, the disordered diffusion of the cooling liquid when the flow direction is reversed can be avoided, preventing local turbulence and energy superposition caused by the intersection of hot and cold fluids in the phase slip layer area. The existence of the energy injection path allows the energy to migrate from the hot area to the cold area while the momentum decays, thereby buffering the reverse impact of the fluid in the main channel. In this way, the cooling liquid flow field forms a controlled backflow in the flow direction reversal stage, and the cooling liquid flow velocity gradient and temperature gradient are redistributed in space, significantly reducing the interference between the flow field and the thermal field. Finally, the entire cooling flow process changes from a sudden change to a gradual change, and the temperature field changes from a shock state to a stable state.

[0073] S004, based on the temperature backflow bypass tail end, a pump speed phase traction sequence is established, a segmented flow direction switching is performed according to the time rhythm of the reverse anchor point, and the flow direction change rate of the cooling liquid is controlled to reduce the reverse superposition effect;

[0074] To weaken the flow field superposition impact caused by flow direction reversal in the energy reflux stage, and to keep the temperature rollback bypass and the main cooling channel balanced during the flow switching process, a pump speed phase traction sequence can be established at the tail end of the temperature rollback bypass. Through the phased regulation of the cooling liquid pump speed and flow direction, the segmented flow direction switching is performed according to the time rhythm of the reversal anchor point, thereby controlling the rate of change of the cooling liquid flow direction and reducing the reverse superposition effect caused by fluid inertia mutation. The specific implementation steps are as follows:

[0075] A pump speed regulation response node is established at the fluid convergence area at the tail end of the temperature rollback bypass. The response node is selected at the position where the temperature rollback bypass intersects with the main cooling channel, that is, the intersection where the cooling liquid reenters the main channel after rolling back through the guide channel. The flow rate, temperature and pressure of the cooling liquid at this point are in a state of dynamic change, and it is the key position for the cooling liquid flow direction to change from the transition zone to the stable zone in the energy reflux stage. In order to realize controllable adjustment of the flow direction change, a monitoring unit for sensing the flow state needs to be set up in this area to form an input reference signal for pump speed response by collecting the cooling liquid flow rate gradient, pressure change trend and temperature distribution characteristics. Based on these signals, the speed control mechanism of the cooling liquid driving pump can establish a traction response relationship at the tail end of the temperature rollback bypass that is synchronized with the cooling liquid flow state, so that the change of pump speed corresponds to the change of cooling liquid flow direction. The technical key of this stage is to determine the time correlation between the pump speed control starting point and the fluid reflux node, so that the pump speed regulation process can enter the pre-response stage in advance when the cooling liquid is about to complete the rollback flow, providing a basic rhythm for the subsequent flow direction switching.

[0076] After the pump speed regulation response node is established, a pump speed phase traction sequence is constructed based on the reversal anchor point as the time reference. The sequence takes the reversal anchor point as the periodic trigger reference, divides the cooling liquid pump speed change process into several phase intervals, and each phase interval corresponds to a transition stage of the cooling liquid flow direction change. By setting the time rhythm in the pump speed phase traction sequence, the pump speed increase and decrease process is matched with the time waveform of the reversal anchor point, thereby forming a continuous time and smooth space flow direction switching process. When the cooling liquid forms a rollback flow along the guide channel in the early stage of energy reflux, the pump speed is in the stable interval; when the cooling liquid starts to enter the main channel at the tail end of the rollback, the pump speed gradually enters the adjustment interval; when the cooling liquid completes the flow direction reversal and enters the reverse flow stage, the pump speed enters the balance interval. In this way, the pump speed phase traction sequence presents a hierarchical regulation feature on the time axis, so that the pump speed change is synchronized with the cooling liquid flow state, preventing pressure pulsation caused by instantaneous flow rate mutation.

[0077] After the pump speed phase traction sequence is constructed, the segmented flow direction switching is performed according to the time rhythm of the reverse anchor point. The segmented flow direction switching takes the temperature roll-back bypass tail end as the starting point, and divides the transition process of the cooling liquid flow direction into multiple continuous stages. The first stage is a pre-adjustment stage, the cooling liquid still partially flows through the temperature roll-back bypass, and the pump speed is slowly adjusted to form a weak flow direction transfer trend; the second stage is a transition stabilization stage, the cooling liquid forms a fluid distribution between the roll-back bypass and the main channel, and the pump speed slightly fluctuates with the rhythm of the reverse anchor point, so that the flow direction conversion is gradually promoted; the third stage is a complete reverse stage, the cooling liquid completes the direction switching in the main channel, the pump speed changes into a stable interval, and the flow direction changes from transition flow to stable backflow. The process of segmented flow direction switching releases the flow inertia of the cooling liquid in stages, thereby preventing the formation of shock waves in the initial reverse flow of the cooling liquid. Since each stage is coupled with the time rhythm of the reverse anchor point, the overall process of the cooling liquid flow direction change presents time continuity and flow smoothness, thereby eliminating the fluid superposition phenomenon caused by the sudden change of the cooling liquid flow direction.

[0078] After the segmented flow direction switching is completed, the rate of change of the cooling liquid flow direction is controlled and the reverse superposition effect is reduced by dynamically adjusting the tail section of the pump speed phase traction sequence. This process takes the cooling liquid flow rate and temperature distribution at the tail end of the temperature roll-back bypass as a feedback reference, and adjusts the pump speed change amplitude and time interval to keep the acceleration and deceleration process of the cooling liquid flow rate smooth. When the cooling liquid is completely in the reverse flow state in the main channel, the tail end of the pump speed traction sequence enters the stable control stage, and the change of the cooling liquid flow rate tends to be constant. At this time, the residual heat in the temperature roll-back bypass is gradually introduced into the reverse flow in the main channel, realizing the energy re-equilibrium inside the flow field. By controlling the rate of change of the cooling liquid flow direction, the spatial distribution of fluid kinetic energy and thermal energy is adjusted synchronously, thereby effectively weakening the reverse superposition effect of the cooling liquid in the energy return stage and preventing secondary disturbance of the cooling liquid flow field. The whole process ensures that the pump speed change and the cooling liquid flow direction are consistent in time, so that the fluid forms a dynamic balance between energy return and heat dissipation, and finally stabilizes the flow state of the cooling liquid flow field.

[0079] S005, a heat balance scheduling window is set at the tail end of the pump speed phase traction sequence, the position of the reverse anchor point is adjusted and the cooling flow direction weight is compressed under the time rhythm, the temperature distribution of the battery cell is maintained stable through time sequence scheduling, and the heat balance state of the battery system is maintained;

[0080] To maintain the balance of the temperature distribution of the battery cell and prevent the thermal imbalance and temperature drift caused by the lag of the cooling liquid flow adjustment during the flow field regulation in the energy return phase, a thermal balance scheduling window can be set at the end of the pump speed phase traction sequence, the position of the reverse anchor point is dynamically adjusted by time rhythm, and the cooling flow weight is compressed on this basis, so that the cooling liquid forms a rhythmic temperature stable interval during the flow process, thereby maintaining the stability of the temperature distribution of the battery cell in the time dimension and keeping the overall thermal balance of the battery system. The specific implementation steps are as follows:

[0081] The time boundary of the thermal balance scheduling window is established at the end of the pump speed phase traction sequence. The thermal balance scheduling window is based on the termination phase of the pump speed phase traction sequence, and the time boundary corresponds to the time interval when the cooling liquid completes the segmented flow switching and enters the stable return phase. At this time, the flow direction of the cooling liquid has stabilized, the flow inertia gradually dissipates, and the residual heat in the temperature rollback bypass is guided into the return path of the main channel. At this stage, the flow rate of the cooling liquid is relatively stable, and the heat distribution among the battery cells tends to be balanced, which is the key time window for thermal balance scheduling. To make full use of the window for thermal management scheduling, a time rhythm signal corresponding to the time period of the reverse anchor point is preset in the cooling channel, and the rhythm signal is used as the synchronous trigger condition of the thermal balance scheduling window. When the rhythm signal enters the tail end phase, the scheduling window is automatically opened to receive and regulate the cooling liquid temperature, flow rate and pressure information from the end of the flow switching. By setting the time boundary, the thermal balance scheduling window forms a controllable thermal scheduling period at the end of the pump speed phase traction sequence, providing a time basis for the dynamic adjustment of the reverse anchor point.

[0082] After the thermal balance scheduling window is opened, the position of the reverse anchor point is dynamically adjusted based on the time rhythm. The reverse anchor point is originally the time and space reference point of the flow direction reversal of the cooling liquid. During the execution of the pump speed phase traction sequence, the position of the reverse anchor point is fixed at the initial area of the energy return. When the thermal balance scheduling window enters the working state, the time position of the reverse anchor point can be periodically shifted according to the rhythm of the cooling liquid flow direction and temperature change. Through this time adjustment, a moving thermal balance center is formed inside the flow field, so that the temperature distribution of the cooling liquid in different rhythm periods always develops around the reverse anchor point, thereby suppressing the local heat accumulation phenomenon caused by energy return. Specifically, when the flow rate of the cooling liquid decreases and the temperature rises in the main channel, the reverse anchor point is slightly shifted to the front end of the time sequence to trigger the flow direction adjustment earlier, so that the cooling liquid enters the uniform temperature stage earlier. When the temperature of the cooling liquid decreases and the flow rate recovers, the reverse anchor point is extended to the rear end of the time sequence to prolong the energy release period. Through this rhythm adjustment in the time dimension, the reverse anchor point can be in the most favorable heat exchange position in each thermal balance period, thereby maintaining the continuity of heat transfer and the stability of flow control in the time axis.

[0083] After the dynamic adjustment of the reverse anchor point position according to the time rhythm is completed, the cooling flow direction weight compression is started. The cooling flow direction weight reflects the flow proportion of the cooling liquid in different flow direction stages. When the cooling liquid changes from forward flow to reverse flow, if the flow weight distribution in each direction is too balanced, it is easy to cause the hot and cold fluids to form a hedge in the main channel, thereby causing local temperature oscillation. To avoid this phenomenon, during the working period of the thermal balance scheduling window, the cooling flow direction weight is compressed and adjusted, so that the fluid momentum in the reverse flow stage is gradually weakened, and the amplitude of the flow direction switching is limited in space. The flow direction change speed of the cooling liquid in the area close to the tail end of the temperature roll-back bypass is appropriately reduced, while the flow direction speed in the area far from the phase error layer area of the main channel remains stable. Through the compression of the flow direction weight in space, the cooling liquid forms a gradual speed transition layer in different areas, making the energy transfer between hot and cold fluids more smooth, and avoiding the formation of flow superposition around the reverse anchor point. The technical core of this process lies in controlling the proportion of the cooling liquid flow direction, so that the temperature gradient in the main channel is continuously compressed, and a stable temperature distribution structure is formed.

[0084] After the dynamic adjustment of the reverse anchor point and the compression of the flow direction weight in the thermal balance scheduling window are completed, the time sequence scheduling is used to maintain the stability of the battery cell temperature distribution and ensure the thermal balance state of the battery system. The time sequence scheduling takes the time rhythm of the thermal balance scheduling window as the control main line, and adjusts the cooling liquid flow parameters in each rhythm period to keep the temperature change and flow speed change synchronized. When the cooling liquid temperature is too high, the scheduling window triggers the reverse flow adjustment in the next period; when the cooling liquid temperature is too low, the scheduling window delays the trigger to prolong the heat accumulation time. Through this continuous scheduling based on time rhythm, the cooling liquid can automatically adapt to the change of energy flow direction in each thermal balance period, and realize the uniform distribution of temperature in space. Finally, the temperature difference between the battery cells is maintained within a stable range, and the heat transfer in the battery pack presents a balance state, and the cooling liquid flow field no longer appears periodic temperature fluctuation. This process not only balances the interaction between the cooling liquid flow direction and the temperature field, but also establishes a continuous and stable thermal management rhythm in the time dimension, so that the battery system can maintain stable operation under long-time energy backflow conditions.

[0085] The application can realize real-time control of the dynamic relationship between the cooling liquid flow direction change and the heat conduction path by constructing a cooling flow direction synchronous sensing chain and a phase difference distribution model in the energy reflux stage. When the flow direction reverses, the time and space state of the cooling liquid flow can be captured and adjusted synchronously based on the reverse anchor point, so as to avoid the superposition of the cooling flow field and the heat flow conduction field in the transition stage. By accurately marking the starting point of the flow direction reversal, the heat flow transfer can be kept continuous in the direction conversion, the uniformity of the temperature distribution is significantly improved, the periodic fluctuation of heat in the battery cell is inhibited, and the thermal response stability of the battery pack is improved.

[0086] The application can make the cooling liquid flow have the functions of buffering and rhythm regulation in the reverse process by establishing a temperature roll-back bypass and a pump speed phase traction sequence. The flow direction change is changed from mutation to gradual change, the pump speed adjustment is consistent with the rhythm of the reverse anchor point, and the kinetic energy of the cooling liquid and the heat distribution are gradually balanced. The thermal balance scheduling window realizes dynamic thermal scheduling under the time rhythm, so that the temperature difference between the battery cells is kept in a stable range, and local overheating or overcooling caused by flow field impact is avoided, thereby improving the operation safety and service life of the battery system under complex operation conditions.

[0087] The application provides a battery thermal management system based on a new energy agricultural machine, as shown in Figure 2 The battery thermal management system based on the new energy agricultural machine comprises a flow direction sensing module, a phase analysis module, a guide bypass module, a flow direction control module and a thermal balance scheduling module.

[0088] The flow direction sensing module constructs an energy reflux cooling flow direction synchronous sensing chain, detects the change of the cooling liquid flow direction in real time, captures the dynamic characteristics at the moment of the cooling liquid flow direction reversal, marks the starting point of the flow direction reversal and generates a reverse anchor point.

[0089] The phase analysis module establishes a phase difference distribution model of the cooling flow field and the heat flow conduction based on the reverse anchor point, calculates the difference between the cooling flow phase and the heat conduction phase, forms a phase difference distribution map, identifies the phase misregistration area and determines the temperature shock source.

[0090] The guide bypass module constructs reverse guide channels on both sides of the phase misregistration area, forms a temperature roll-back bypass through the guide channels, limits the energy injection path to buffer the reverse impact of the cooling flow field.

[0091] The flow direction control module establishes a pump speed phase traction sequence based on the tail end of the temperature roll-back bypass, performs segmented flow direction switching according to the time rhythm of the reverse anchor point, controls the flow direction change rate of the cooling liquid to reduce the reverse superposition effect.

[0092] The thermal balance scheduling module sets a thermal balance scheduling window at the tail end of the pump speed phase traction sequence, adjusts the position of the reverse anchor point and compresses the weight of the cooling flow direction under the time rhythm, maintains the stability of the battery cell temperature distribution through time sequence scheduling, and keeps the thermal balance state of the battery system.

[0093] The battery thermal management method based on the new energy agricultural machine is implemented through the battery thermal management system based on the new energy agricultural machine, and the specific method and process of the battery thermal management system based on the new energy agricultural machine are described in the above embodiment of the battery thermal management method based on the new energy agricultural machine, which will not be described here.

[0094] The above only describes some exemplary embodiments of the present application by way of illustration, and it is needless to say that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present application. Therefore, the above drawings and descriptions are illustrative in nature and should not be understood as limiting the scope of protection of the claims of the present application.

Claims

1. A battery thermal management method based on new energy agricultural machinery, characterized in that, Includes the following steps: S001, Construct an energy return cooling flow direction synchronous sensing chain to detect changes in coolant flow direction in real time, capture the dynamic characteristics of the moment when the coolant flow direction reverses, calibrate the flow direction reversal starting point and generate reversal anchor point; S002, establish a phase difference distribution model of cooling flow field and heat conduction with the reversal anchor point as the center, calculate the difference between cooling flow phase and heat conduction phase, form a phase difference distribution map, identify phase misalignment region and determine temperature oscillation source; S003, constructs reverse guidance channels on both sides of the phase misalignment region, forms a temperature rewind bypass through the guidance channels, and limits the energy reinjection path to buffer the reverse impact of the cooling flow field; S004, based on the temperature rewind bypass tail end, establish the pump speed phase traction sequence, and perform segmented flow direction switching according to the time rhythm of the reverse anchor point to control the coolant flow direction change rate to reduce the reverse superposition effect. S005 sets a thermal balance scheduling window at the end of the pump speed phase traction sequence, adjusts the position of the reversal anchor point and compresses the cooling flow weight under the time rhythm, and maintains the stability of the cell temperature distribution through time-series scheduling to maintain the thermal balance state of the battery system.

2. The battery thermal management method based on new energy agricultural machinery according to claim 1, characterized in that, Step S001 includes: Multi-point flow direction detection units are set in the key flow paths of the coolant circulation loop. The flow direction, flow velocity and flow pressure of the coolant during the energy output stage are continuously collected by the flow detection sensing components to form a continuous flow state data stream. After completing the flow state data acquisition, based on the time comparison results of coolant velocity vector and pressure gradient, the initial signs of coolant flow reversal are identified, and the trend change process of coolant flow reversal is extracted. After identifying the trend of coolant flow reversal, the changes in coolant flow rate, pressure and temperature are continuously tracked to capture the transition process of coolant flowing from the forward direction to the reverse direction and to calibrate the critical moment of flow reversal. After capturing the critical moment of flow reversal, the starting point of flow reversal is calibrated and a reversal anchor point is generated based on the combined characteristics of coolant flow direction, pressure and temperature, which is used as a reference time signal for subsequent thermal management control.

3. The battery thermal management method based on new energy agricultural machinery according to claim 2, characterized in that, Step S002 includes: After completing the calibration of the coolant flow reversal anchor point, the coolant flow rate, pressure and temperature change data are collected with reference to the time node and spatial location corresponding to the reversal anchor point, and the basic distribution framework of the cooling flow field is established. After establishing the basic distribution framework of the cooling flow field, multiple equidistant sampling points are divided along the length of the cooling channel to spatially map the coolant flow state and the heat conduction state, and calculate the difference between the cooling flow phase and the heat conduction phase. After obtaining the difference between the cooling flow phase and the heat conduction phase, a phase difference distribution map is formed with the reversal anchor point as the center, and the phase misalignment region between the cooling flow field and the heat conduction is depicted in the distribution map. After forming the phase difference distribution map, the phase gradient change in the phase misalignment zone is identified, the region with the largest phase shift between cooling flow and heat conduction is determined, and the center point of this region is identified as the temperature oscillation source.

4. The battery thermal management method based on new energy agricultural machinery according to claim 3, characterized in that, The source of temperature oscillation is determined based on the location of the largest phase gradient change in the phase difference distribution diagram, and confirmed by combining the spatial intersection area of ​​the coolant flow direction and the heat conduction direction.

5. The battery thermal management method based on new energy agricultural machinery according to claim 3, characterized in that, Step S003 includes: After identifying the phase misalignment region, the region with uneven heat flow distribution in the coolant flow field is determined with the central axis of the phase misalignment region as a symmetry reference, and a guide channel reserved area is set on both sides of the boundary of the phase misalignment region. After completing the setting of the guide channel reserved area, a reverse guide channel parallel to the main cooling channel is established along the outer edge of the phase misalignment area, so that the coolant enters the reverse guide channel to form a rewind flow when the flow direction is reversed. After the reverse guidance channel is established, a temperature rollback bypass is formed through the intersection structure of the reverse guidance channel and the main cooling channel, so that the heat in the coolant can be rolled back and transferred on both sides of the phase misalignment region. After forming a temperature recirculation bypass, the energy reinjection path is defined by the multi-point connection between the reverse guidance channel and the main cooling channel, so that the flow trajectory of the coolant in the energy recirculation stage is controlled and distributed to buffer the reverse impact of the cooling flow field.

6. The battery thermal management method based on new energy agricultural machinery according to claim 5, characterized in that, The inner wall of the reverse guide channel is made of the same material with the same thermal conductivity as the main cooling channel to ensure a smooth transition of the coolant temperature during the guide channel process and prevent local overheating.

7. The battery thermal management method based on new energy agricultural machinery according to claim 5, characterized in that, Step S004 includes: A pump speed control response node is set in the fluid confluence area at the end of the temperature rewind bypass to collect the changes in coolant flow rate, pressure and temperature, forming a reference basis for pump speed control. After setting the pump speed control response node, a pump speed phase traction sequence is constructed with the reversal anchor point as the time reference. The coolant pump speed change is divided into multiple phase intervals so that the pump speed change and the coolant flow direction change are in correspondence. After forming the pump speed phase traction sequence, the segmented flow direction switching is performed according to the time rhythm of the reverse anchor point, so that the coolant gradually completes the flow direction transition between the temperature rewind bypass and the main cooling channel. After completing the segmented flow direction switching, the tail end of the pump speed phase traction sequence is adjusted to control the rate of change of coolant flow direction, so that the momentum change of coolant in the reverse flow stage is gradual, thereby reducing the reverse superposition effect of the cooling flow field.

8. The battery thermal management method based on new energy agricultural machinery according to claim 7, characterized in that, The pump speed control response node is set upstream of the intersection of the temperature rewind bypass and the main cooling channel, and dynamically adjusts the pump speed change range according to the coolant temperature change trend, so that the coolant completes kinetic energy buffering and heat distribution before entering the main cooling channel.

9. The battery thermal management method based on new energy agricultural machinery according to claim 7, characterized in that, Step S005 includes: Establish the time boundary of the thermal balance scheduling window at the end of the pump speed phase traction sequence, so that the thermal balance scheduling window corresponds to the time interval during which the coolant completes the segmented flow direction switching and enters the stable reflux stage. After the thermal balance scheduling window is opened, the position of the reversal anchor point is dynamically adjusted based on the time rhythm, so that the coolant temperature distribution changes around the reversal anchor point in different rhythm cycles. After the reversal anchor point position is adjusted, the cooling flow direction weight is compressed so that the flow proportion of coolant in different flow direction stages forms a gradual distribution. After the flow direction weight compression is completed, the flow state of the coolant is regulated by timing scheduling to keep the cell temperature distribution stable, thereby maintaining the thermal balance of the battery system.

10. A battery thermal management system based on new energy agricultural machinery, used to implement the battery thermal management method based on new energy agricultural machinery as described in any one of claims 1-9, characterized in that, It includes a flow direction sensing module, a phase analysis module, a guidance bypass module, a flow direction control module, and a thermal balance scheduling module: The flow direction sensing module constructs a synchronous sensing chain for energy return cooling flow direction, detects changes in coolant flow direction in real time, captures the dynamic characteristics of the instantaneous reversal of coolant flow direction, calibrates the reversal starting point, and generates reversal anchor points. The phase analysis module establishes a phase difference distribution model of the cooling flow field and heat conduction with the reversal anchor point as the center, calculates the difference between the cooling flow phase and the heat conduction phase, forms a phase difference distribution map, identifies the phase misalignment region, and determines the temperature oscillation source. The guiding bypass module constructs reverse guiding channels on both sides of the phase misalignment region, and forms a temperature rewind bypass through the guiding channels to limit the energy reinjection path and buffer the reverse impact of the cooling flow field. The flow direction control module establishes a pump speed phase traction sequence based on the temperature rewind bypass tail end, and performs segmented flow direction switching according to the time rhythm of the reverse anchor point to control the rate of change of coolant flow direction in order to reduce the reverse superposition effect. The thermal balance scheduling module sets a thermal balance scheduling window at the end of the pump speed phase traction sequence, adjusts the position of the reversal anchor point and compresses the cooling flow weight under the time rhythm, and maintains the stability of the cell temperature distribution through time-series scheduling to maintain the thermal balance state of the battery system.

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