A series battery pack dynamic thermal equalization control system

Abstract

The application relates to the technical field of battery thermal management, and discloses a dynamic thermal equalization control system for a series battery pack, which comprises a heat exchange module inlaid with a micro-channel network and attached to a single battery cell, a phase-change magnetic fluid working medium containing magnetic nanoparticles filled in the micro-channel, and a magnetic field generation module composed of a plurality of independently addressable micro electromagnetic coil arrays. Through a processing and control module, two kinds of active control can be realized: one is to generate a static magnetic field on a non-optimal heat transport path to balance the temperature difference, utilize the magnetic field force to form local flow resistance to the working medium vapor, and direct the vapor carrying latent heat from a high-temperature area to a low-temperature area; the other is to generate a dynamic magnetic field in a hot spot area to drive the magnetic nanoparticles to generate micro disturbances to destroy the thermal boundary layer, thereby significantly strengthening local heat exchange. The application realizes active, accurate and low-energy consumption regulation and control of the temperature field of the battery pack.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management technology, specifically to a dynamic thermal balance control system for a series battery pack. Background Technology

[0002] Lithium-ion batteries are core energy components in key areas such as modern electric vehicles and energy storage power stations. Their performance, lifespan, and safety largely depend on their operating temperature. During charging and discharging, especially at high rates, a large amount of heat is inevitably generated inside the battery due to electrochemical reactions and internal resistance. If this heat is not managed effectively and in a timely manner, it will lead to excessively high battery temperatures, accelerating irreversible aging processes such as electrolyte decomposition and degradation of the positive and negative electrode materials. In severe cases, it may even cause thermal runaway, posing a significant safety hazard.

[0003] Even more challenging is the fact that within a battery pack composed of numerous individual cells connected in series, the heat generation and dissipation conditions of each cell are not uniform due to slight differences in manufacturing processes, varying connection impedances, and differences in their spatial location. This unevenness inevitably leads to a non-uniform temperature field within the battery pack, i.e., a significant temperature gradient. Long-term operation under such a temperature difference environment will result in a "weakest link" effect, where the usable capacity and lifespan of the entire battery pack are determined by the worst-performing cell, such as capacity and internal resistance. Therefore, simply controlling the overall average temperature of the battery pack within an ideal range is far from sufficient. Achieving temperature equilibrium within the battery pack, suppressing localized hotspots, and minimizing maximum temperature differences are long-standing and crucial technical challenges in battery thermal management.

[0004] To address this challenge, various thermal management solutions have been developed. For example, forced air cooling systems are simple in structure, but the air medium has low specific heat capacity and thermal conductivity, resulting in limited heat exchange efficiency and making it difficult to meet the heat dissipation requirements of high-power-density battery packs. As an advanced solution, liquid cooling systems remove heat through circulating coolant, offering higher heat exchange efficiency. However, these systems typically require a series of complex auxiliary components such as water pumps, piping, heat exchangers, and coolant tanks, increasing the overall weight, volume, and manufacturing cost of the system. The continuous operation of the water pump also leads to additional parasitic energy consumption. More importantly, both air cooling and liquid cooling are essentially "global" cooling of the entire battery pack, lacking spatial selectivity. They can transfer heat from the battery pack as a whole to the outside, but they cannot actively and purposefully transfer heat from one overheated cell to another underheated cell within the battery pack, thus limiting their ability to actively reduce internal temperature differences.

[0005] Another technological approach involves using phase change materials or traditional heat pipe technology. These passive thermal management solutions utilize the latent heat of phase change in materials to absorb and conduct heat, requiring no external energy input and offering advantages such as high efficiency and reliability. However, their core limitation lies in the "uncontrollability" of the process. Heat transfer relies entirely on the spontaneously generated temperature gradient within the system; technicians cannot intervene in the path or intensity of heat transfer based on the battery's real-time status. When a cell experiences an emergency hotspot due to a sudden surge in current, this passive system cannot provide additional, enhanced localized heat dissipation; nor can it specify the source and target of heat transfer when intra-pack temperature equalization is required. This lack of proactive control makes it unable to flexibly cope with complex and ever-changing real-world operating conditions.

[0006] Therefore, existing technologies urgently need a new battery thermal management solution that can not only achieve efficient heat transfer, but also has active and precise control capabilities. It should be able to directionally allocate heat within the battery pack to balance the temperature difference as needed, and quickly suppress sudden local hot spots. At the same time, it should overcome the inherent defects of traditional active cooling systems, such as complex structure and high energy consumption. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a dynamic thermal equilibrium control system for series battery packs. This system solves the problems in existing battery thermal management technologies, where efficient phase change heat transfer cannot be actively controlled due to its passive nature, while active cooling systems suffer from complex structures, high energy consumption, and difficulty in achieving precise heat management within the pack.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: The first aspect of this invention provides a dynamic thermal equalization control system for a series battery pack, the system comprising: A heat exchange module is provided, which makes thermal contact with multiple individual cells of a series-connected battery pack. In one specific embodiment, the heat exchange module is a mechanical structural component of the series-connected battery pack, such as a metal separator between individual cells or the metal casing of the individual cells themselves.

[0009] The module contains a three-dimensional interconnected microchannel network that covers the surface of the multiple individual battery cells and is vacuum-sealed with a phase change magnetohydrodynamic working fluid inside the network.

[0010] The phase-change magnetohydrodynamic working fluid is composed of an insulating dielectric liquid base with a preset phase-change temperature and magnetic nanoparticles uniformly suspended in the base liquid.

[0011] A magnetic field generating module is disposed on the heat exchange module, and its spatial position corresponds to at least a portion of the microchannel network. This module is capable of generating a controllable static or dynamic magnetic field at a specified location based on an external control signal. In one specific embodiment, this module is a miniature electromagnetic array.

[0012] The processing and control module is electrically connected to the temperature sensor and the magnetic field generating module configured within the series battery pack.

[0013] The processing and control module is configured to perform the following functions: Based on real-time temperature data obtained from the temperature sensor, one or more thermal equilibrium control operations are performed, specifically including: Directed heat dispatch based on static magnetic field When the processing and control module determines that there are heat source cells and heat target cells within the battery pack that require targeted heat management, it controls the magnetic field generation module to generate a static magnetic field at a microchannel network outside the target path. This static magnetic field applies a magnetic force to the phase change magnetohydrodynamic working fluid. This magnetic force creates local flow resistance within the channel, sufficient to impede the passage of the working fluid vapor phase. Consequently, the working fluid vapor originating from the heat source cell is guided to the only low-resistance target path, flowing towards the heat target cell where it condenses and releases heat.

[0014] The magnetic force density F generated by this static magnetic field in the phase-change magnetohydrodynamic working fluid mFm can be characterized by the following formula: ; in, It represents the magnetic field force density; The vacuum permeability; The magnetization intensity of the phase-change magnetohydrodynamic working fluid; For gradient operators; The magnetic field strength of the static magnetic field is given.

[0015] Based on the localized heat transfer enhancement using a dynamic magnetic field, when the processing and control module determines that there are localized hot spots within the battery pack requiring enhanced heat transfer, it controls the magnetic field generation module to generate a dynamic magnetic field at the microchannel network corresponding to the hot spot. This dynamic magnetic field applies a time-varying magnetic torque to the magnetic nanoparticles in the phase-change magnetohydrodynamic working fluid, driving the nanoparticles to generate controlled microscopic vibrations or rotations near the thermal boundary layer. This microscopic disturbance disrupts the static thermal boundary layer, thereby enhancing the local convective heat transfer coefficient.

[0016] The dynamic magnetic field exerts a magnetic torque on a single magnetic nanoparticle. It can be represented by the following formula: ; in, The magnetic torque acting on a single magnetic nanoparticle; The vacuum permeability; The volume of a single magnetic nanoparticle; The magnetization intensity of a single magnetic nanoparticle; For cross product operators; The magnetic field strength of the dynamic magnetic field is given.

[0017] In the coordinated control, when the processing and control module determines that there are both local hot spots and low-temperature regions in the battery pack, it coordinates the execution of the above two operations: controlling the magnetic field generation module to generate a static magnetic field to construct a directional transport channel from the local hot spot to the low-temperature region, and simultaneously generating a dynamic magnetic field at the local hot spot to enhance heat exchange at the hot spot.

[0018] A second aspect of the present invention provides a dynamic thermal equalization control method for a series battery pack, which is applied to the above-mentioned system and includes the following steps: Real-time monitoring of the temperature distribution of the series-connected battery pack; Based on the monitored temperature distribution, it is determined whether there are target areas in the series battery pack that require targeted heat management or strong local heat exchange. In response to the determination that the target region exists, the micro electromagnetic array is controlled to perform a corresponding magnetic field generation operation for the target region, wherein: If the target area requires directional heat dispatch, a static magnetic field is generated to guide the flow path of the phase change magnetohydrodynamic working fluid. If the target area requires enhanced local heat transfer, a dynamic magnetic field is generated to improve the local convective heat transfer coefficient.

[0019] This invention provides a dynamic thermal equalization control system for series-connected battery packs. It has the following beneficial effects: 1. This invention generates a static magnetic field by controlling a micro-electromagnetic array, which can create a local high flow resistance region at any location within a microchannel network, thus constructing a programmable magnetohydrodynamic valve. This allows the phase-change magnetohydrodynamic working fluid that evaporates due to heat to be forcibly guided and transported directionally along a preset path from any high-temperature cell to any low-temperature cell, thereby overcoming the technical deficiency of traditional thermal management systems that cannot actively and accurately perform internal heat scheduling.

[0020] 2. This invention utilizes a dynamic magnetic field to drive the magnetic nanoparticles in the phase-change magnetohydrodynamic working fluid to generate microscopic disturbances, which can actively disrupt and thin the static thermal boundary layer at the heat exchange wall. This approach can instantly and locally enhance the convective heat transfer coefficient without increasing the total system flow rate or pumping power consumption, thereby achieving rapid response and effective suppression of sudden local hot spots.

[0021] 3. This invention integrates thermal management functions with the mechanical structure of the battery pack, eliminating the need for additional liquid cooling plates and other components, thus reducing the system's added weight and volume. Simultaneously, by actively and directionally transferring heat from high-risk hotspots and using it to preheat cryogenic cells, it achieves the recycling of internal heat energy within the battery pack, avoiding simple heat dissipation to the outside and improving the overall energy efficiency of the system. Attached Figure Description

[0022] Figure 1 This is a system architecture diagram of the present invention; Figure 2 This is a flowchart of the method of the present invention.

[0023] Among them, 10 is the heat exchange module; 20 is the magnetic field generation module; 30 is the processing and control module; and 40 is the individual battery cell. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example: Please see the appendix Figure 1 This invention provides a dynamic thermal equalization control system for a series battery pack, comprising: The heat exchange module 10 is in contact with multiple individual cells of a series battery pack. The heat exchange module is a mechanical component of the series battery pack. It has a microchannel network covering multiple individual cells inside and a phase change magnetohydrodynamic working fluid is sealed inside the microchannel network. The core function of the heat exchange module 10 is to serve as a heat transfer medium between the phase-change magnetohydrodynamic working fluid and the individual battery cells 40. In one specific embodiment, the heat exchange module 10 is designed as an integrated thermal management structure. This structure is directly integrated into the physical structure of the series battery pack, rather than an additional, separate thermal management accessory. For example, when the series battery pack consists of multiple square or pouch cells 40 arranged side by side, the heat exchange module 10 can be a metal separator disposed between adjacent individual cells 40. This separator is made of 6061 aluminum alloy or C11000 copper with high thermal conductivity, and it provides the necessary electrical insulation and mechanical support between the cells while undertaking the heat exchange function.

[0026] Inside this integrated thermal management structure, a microchannel network of a predetermined configuration is arranged. This microchannel network is formed on a metal substrate using processes such as CNC micromilling or chemical etching. Subsequently, a cover plate of the same material is sealed to the substrate via laser welding or vacuum brazing, thus forming a closed internal flow channel. The layout of the microchannel network is precisely designed to ensure effective coverage of the main heat-generating areas of each individual cell. For example, the channels can employ a serpentine layout to extend the residence path of the working fluid in specific hot spots, or a manifold-parallel channel layout to achieve uniform coverage of the cell surface. The equivalent hydraulic diameter of the microchannels is controlled within the range of 100 micrometers to 3 millimeters, and their cross-sectional shape can be rectangular, trapezoidal, or circular.

[0027] Inside the microchannel network of the heat exchange module 10, after rigorous cleaning and drying, a specific amount of phase change magnetic fluid is injected, followed by vacuum sealing. This phase change magnetic fluid is a two-component composite fluid, consisting of a dielectric liquid base and magnetic nanoparticles uniformly dispersed in the base liquid.

[0028] The selection criterion for the dielectric liquid base fluid is that it has a phase transition temperature (boiling point) that matches the safe operating temperature range of the battery pack. For example, for lithium-ion batteries with an upper operating temperature limit of 55°C, hydrofluoroethers or insulating hydrocarbons with a boiling point of around 50°C can be selected as the base fluid. Their dielectric properties ensure that even if the working fluid leaks under extreme conditions, it will not cause an electrical short circuit inside the battery pack.

[0029] Magnetic nanoparticles provide the working fluid with magnetic response characteristics. In this embodiment, spherical iron oxide (Fe3O4) particles with an average particle size of 10 nanometers are used. To prevent the nanoparticles from agglomerating and settling in the base fluid due to van der Waals forces or magnetic dipole interactions, an oleic acid molecule layer is chemically grafted onto the particle surface as a surfactant. This surfactant layer forms steric hindrance between the particles, ensuring the long-term existence of the phase change magnetohydrodynamic (MHD) working fluid as a stable colloidal suspension. The volume concentration of magnetic nanoparticles in the base fluid is set within the range of 1% to 8% to achieve a balance between obtaining sufficient magnetic response capability and maintaining low fluid viscosity.

[0030] The phase change magnetohydrodynamic working fluid is vacuum-sealed inside the microchannel network of the heat exchange module 10. It is an engineered two-component composite functional fluid consisting of a dielectric liquid base fluid and multiple magnetic nanoparticles uniformly and stably suspended therein.

[0031] The dielectric base fluid is the continuous phase of the working fluid, and its core function is to provide phase change heat transfer capability. The selection of the base fluid must meet several technical specifications. Its phase change temperature, i.e., the boiling point at standard atmospheric pressure, is selected based on the target operating temperature window of the series-connected battery pack. For example, for a lithium-ion battery system with a safe operating upper limit of 60°C, hydrofluoroether (HFE) or perfluoropolyether with a boiling point in the range of 50°C to 55°C can be selected as the base fluid. Furthermore, the base fluid has high volume resistivity and dielectric strength to ensure that even if working fluid leakage occurs under any operating condition, it will not cause an electrical short circuit risk within the battery pack.

[0032] Magnetic nanoparticles are the solid-phase dispersion of the working fluid, and their function is to impart responsiveness to external magnetic fields to the fluid. In this embodiment, spherical iron oxide particles with an average particle size between 5 nanometers and 20 nanometers are used. This particle size range ensures that the nanoparticles exhibit superparamagnetism, meaning they only exhibit magnetism when an external magnetic field is applied, and their residual magnetism is zero after the magnetic field is removed. This fundamentally avoids irreversible magnetic agglomeration between particles caused by residual magnetism.

[0033] To achieve long-term stable suspension of magnetic nanoparticles in a dielectric liquid base, i.e., to overcome the van der Waals forces and magnetic dipole interactions between particles, the surface of each nanoparticle undergoes chemical modification. Specifically, a layer of long-chain organic molecules, such as oleic acid or citric acid, is grafted onto the particle surface via chemical bonding as a surfactant. This surfactant layer forms effective steric hindrance or electrostatic repulsion between adjacent particles, thereby preventing particle aggregation and sedimentation, and ensuring that the phase change magnetohydrodynamic working fluid maintains uniform colloidal properties throughout its service life.

[0034] The volume concentration of magnetic nanoparticles in the dielectric liquid base is an optimized technical parameter, set between 1% and 8%. This concentration range is designed to balance two technical objectives: on the one hand, to ensure that the working fluid has a sufficiently high saturation magnetization to respond to an external magnetic field and generate the required magnetic force or torque; On the other hand, it avoids a significant increase in the viscosity of the working fluid due to excessively high solid particle concentration, thereby maintaining its low flow resistance characteristics necessary for a two-phase flow working fluid when there is no magnetic field.

[0035] A magnetic field generating module 20 is disposed on the heat exchange module 10 and corresponds to at least a portion of the microchannel network; The function of the magnetic field generation module 20 is to generate a specific type of magnetic field at a designated location in the heat exchange module 10 according to the instructions issued by the processing and control module 30.

[0036] In one specific embodiment, the magnetic field generating module 20 is a miniature electromagnetic array. The physical carrier of this array can be a rigid multilayer printed circuit board or a deformable flexible circuit board (FPC). The circuit board substrate, such as an FR-4 epoxy resin board or a polyimide film, has multiple independent planar spiral coils made of copper foil etched onto one or more layers using standard circuit manufacturing processes. Each planar spiral coil constitutes an independent electromagnetic unit.

[0037] The micro-electromagnetic array is precisely laminated or attached to the outer surface of the heat exchange module 10, and its position corresponds precisely to the microchannel network inside the heat exchange module 10. The array and the heat exchange module 10 are fixed together by a thin layer of adhesive with high thermal conductivity and electrical insulation to ensure good thermal contact and electrical isolation between the two.

[0038] Each planar helical coil in the array, or a unit group consisting of a few coils, has an independent electrical lead. These leads are connected to a multi-channel driver integrated circuit via wiring on a circuit board. This driver integrated circuit is controlled by the processing and control module 30, thereby enabling independent addressing and current driving of any one or more coils in the array.

[0039] When a static magnetic field needs to be generated, the processing and control module 30 instructs the drive circuit to pass a constant direct current into one or more selected planar helical coils 21. This direct current generates a stable static magnetic field with a specific spatial gradient around the coil. The magnetic field gradient acts on the phase-change magnetohydrodynamic working fluid within the microchannel network, generating a macroscopic magnetic field force density. It is used to create local flow resistance.

[0040] When a dynamic magnetic field needs to be generated, the processing and control module 30 instructs the drive circuit to pass a time-varying current through one or more selected planar helical coils. This current can be an alternating current or pulsating direct current in the form of a sine wave, square wave, or pulse sequence at a specific frequency (e.g., in the range of 10 Hz to 10 kHz). This time-varying current generates a dynamic magnetic field that also varies with time. It acts on individual magnetic nanoparticles in a phase-change magnetohydrodynamic working fluid, applying a time-varying magnetic torque. It is used to drive the microscopic movement of particles.

[0041] The processing and control module 30 is electrically connected to the temperature sensor and magnetic field generation module 20 of the series battery pack. The processing and control module 30 is configured to: based on real-time data from the temperature sensor, control the magnetic field generation module to generate a static magnetic field or a dynamic magnetic field, so as to control the flow path of the phase change magnetohydrodynamic working fluid in the microchannel network and enhance the local convective heat transfer coefficient.

[0042] The processing and control module 30 is the centralized control unit of the present invention, which is responsible for performing all functions of data acquisition, status judgment, decision making and control command output.

[0043] In one specific embodiment, the processing and control module 30 can be a dedicated microcontroller unit, a field-programmable gate array (FPGA), or an integrated functional module on the battery management system motherboard. This module includes one or more processor cores, non-volatile memory for storing control algorithms and preset parameters, and random access memory for caching real-time data during operation.

[0044] The processing and control module 30 establishes an electrical connection with other parts of the system through its input / output interface. Its input terminals are connected to multiple temperature sensors located on the surface or at key locations of each individual battery cell 40. These temperature sensors can be negative temperature coefficient thermistors or digital temperature sensors. The processing and control module 30 periodically reads the measured values ​​from all temperature sensors through its built-in analog-to-digital converter channel or a dedicated digital communication bus, thereby constructing a data matrix characterizing the real-time temperature distribution of the entire battery pack.

[0045] The output of the processing and control module 30 is electrically connected to the magnetic field generating module 20. This connection is typically achieved through a multi-channel, high-current driver integrated circuit. The processing and control module 30 generates low-voltage logic level control signals (such as PWM signals or serial data) and sends them to the driver circuit. The driver circuit then converts these logic signals into operating current sufficient to drive the corresponding coils in the miniature electromagnetic array to generate the target magnetic field strength.

[0046] The control algorithm embedded within the processing and control module 30 is the foundation for realizing the functions of this invention. This algorithm includes at least a data acquisition and diagnostic program and a control decision and execution program. The data acquisition and diagnostic program is responsible for updating the battery pack's temperature data matrix in real time and calculating key performance indicators, such as the highest temperature value, the lowest temperature value, and the maximum temperature difference, based on this matrix.

[0047] The control decision and execution procedure determines whether and how to activate the magnetic field generation module 20 based on the performance indicators obtained from the preset control logic and diagnostic procedure.

[0048] In one embodiment, the operation of the series battery pack dynamic thermal equalization control system can be divided into passive thermal equalization mode and active control mode, depending on whether an external magnetic field is applied.

[0049] In passive thermal equilibrium mode, the processing and control module 30 does not apply control current to the magnetic field generation module 20. At this time, the system operates as a highly efficient pulsating heat pipe without external intervention. When the temperature of a single battery cell 40 rises and exceeds the phase change temperature of the phase change magnetohydrodynamic (MHD) working fluid, the working fluid in the microchannels near that cell absorbs heat and undergoes a phase change, evaporating from a liquid base liquid into vapor. The vapor flows to a lower temperature region within the microchannel network due to increased local pressure, condenses on the channel walls in the low-temperature region, and releases its latent heat of vaporization, thus rapidly transferring heat from the high-temperature region to the low-temperature region. The condensed liquid working fluid flows back to the evaporation section under the influence of gravity or capillary force, forming a continuous, passive heat transfer cycle.

[0050] In active control mode, the processing and control module 30 executes one or more active control strategies based on real-time temperature data, specifically including: Directional heat management based on static magnetic field: When the processing and control module 30 determines that there are heat source cells (high-temperature zone) and heat target cells (low-temperature zone) within the battery pack that require heat management, this mode will be activated. The processing and control module 30 first plans the optimal heat transport path connecting the source and target based on the temperature distribution map, and identifies all microchannel network branches that are not on this optimal path and need to be shut down. Subsequently, it controls the magnetic field generation module 20 to supply a constant DC current to the micro-electromagnetic coils covering these non-target path branches, thereby generating a high-gradient static magnetic field at these locations. This static magnetic field acts on the phase-change magnetohydrodynamic working fluid flowing through this region. Due to the presence of magnetic nanoparticles in the working fluid, the entire fluid exhibits macroscopic magnetism. In the high-gradient magnetic field, the fluid experiences a high volumetric magnetic force density. It can be represented by the following formula: ; in: It represents the magnetic field force density, and its direction points towards the magnetic field strength. The fastest growing sector; The vacuum permeability; The overall magnetization vector of the phase-change magnetohydrodynamic working fluid; For gradient operators; is the magnetic field strength vector of the static magnetic field.

[0051] This magnetic force An additional pressure drop, opposite to or perpendicular to the flow direction of the working fluid vapor, is formed within the channel; this constitutes a localized, non-physically contacted flow resistance. By adjusting the applied current intensity, the magnitude of this resistance can be precisely controlled to prevent the vapor phase from flowing through this non-target path. Thus, the high-pressure vapor generated from the heat source cell is forcibly guided to flow only along the single, open, optimal path without additional magnetic resistance to the heat target cell, where it condenses and releases heat. This achieves active and precise heat management within the battery pack.

[0052] Local heat transfer enhancement based on dynamic magnetic field When the processing and control module 30 determines that a local hot spot has appeared in a single cell of the battery pack and needs to be quickly suppressed, this mode will be activated.

[0053] The processing and control module 30 first precisely locates the physical position of the local hot spot on the heat exchange module 10, and then controls the magnetic field generation module 20 to pass a time-varying current, such as a square wave or sine wave current with a frequency in the range of 10Hz to 10kHz, into the miniature electromagnetic coil covering the area. This time-varying current generates a dynamic magnetic field that also varies with time.

[0054] The dynamic magnetic field A phase-change magnetohydrodynamic working fluid that acts within the thermal boundary layer of the microchannel in the hot spot region, adjacent to the heat exchange wall. It applies a time-varying magnetic torque to each magnetic nanoparticle with a magnetic moment. This torque can be characterized by the following formula: ; in: The magnetic torque vector acting on a single magnetic nanoparticle; The vacuum permeability; The volume of a single magnetic nanoparticle; The magnetization vector of a single magnetic nanoparticle; For cross product operators; This is the magnetic field strength vector of the dynamic magnetic field.

[0055] Under the influence of this alternating magnetic torque, the magnetic nanoparticles within the thermal boundary layer undergo controlled, high-frequency microscopic translational vibrations or in-situ rotations. These microscopic movements strongly disturb the thermal boundary layer, which was originally in a laminar state, disrupting its static structure and promoting the mixing of fluids inside and outside the boundary layer. This significantly reduces the convective heat transfer resistance in local areas, thus enhancing the local convective heat transfer coefficient. This allows heat at hotspots to be transferred more quickly to the mainstream working fluid and carried away, achieving immediate and efficient suppression of local hotspots.

[0056] See attached document Figure 2 Another embodiment of the present invention provides a dynamic thermal equalization control method for a series battery pack, the method comprising the following steps: S100: Real-time monitoring of temperature distribution The processing and control module 30 collects temperature data from multiple temperature sensors located on the surface or at key locations of each individual battery cell 40 via its input interface at a preset sampling frequency. The collected data is organized into a real-time updated temperature data matrix, which fully characterizes the thermal field distribution of the entire series battery pack at the current moment.

[0057] S200: Diagnose thermal condition and determine target area The processor inside the processing and control module 30 executes a diagnostic program to analyze the real-time temperature data matrix obtained in S100 to determine whether there is a target area requiring thermal equalization control. Specifically, the program calculates the following key performance indicators: Maximum temperature inside the battery pack and its physical location; Minimum temperature inside the battery pack and its physical location; Maximum temperature difference inside the battery pack .

[0058] The program then compares the calculated metrics with preset control thresholds stored in its non-volatile memory to determine the type of the target region. If we determine the current maximum temperature difference Greater than the first preset threshold (For example, If this is the case, then a target area requiring targeted heat dispatch has been identified. This target area contains a heat source ( (location) and a heat target ( (Location).

[0059] To determine the current highest temperature value Greater than the second preset threshold (For example, If this is the case, then a target region requiring localized heat transfer enhancement has been identified. This target region is... The physical location of the location.

[0060] S300: Executes the corresponding magnetic field generation operation in response to the judgment result. In response to the determination of the existence of one or more target regions in S200, the processing and control module 30 will control the magnetic field generation module 20 to perform corresponding magnetic field generation operations for the target regions: If it is determined that there is a target area that requires targeted heat dispatch, the processing and control module 30 instructs the drive circuit to apply a constant DC current to the miniature electromagnetic coil located on the non-optimal heat transport path to generate a static magnetic field for guiding the flow of working fluid vapor.

[0061] If it is determined that there is a target area that needs to be enhanced in local heat transfer, the processing and control module 30 instructs the drive circuit to apply a time-varying current with a preset frequency and amplitude to the miniature electromagnetic coil covering the hot spot area to generate a dynamic magnetic field for enhancing local heat transfer.

[0062] When two types of target areas exist simultaneously, the processing and control module 30 will collaboratively execute the two magnetic field generation operations described above. If no target area is identified in S200, no active control operation is performed, and the system operates in passive thermal equalization mode. The steps from S100 to S300 constitute a closed-loop control cycle, which is executed repeatedly at a set frequency, thereby achieving continuous and dynamic control of the battery pack temperature.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A dynamic thermal equilibrium control system for a series-connected battery pack, characterized in that, include: A heat exchange module is in contact with multiple individual cells of a series battery pack, and the heat exchange module is a mechanical structural component of the series battery pack. It has a microchannel network covering the multiple individual cells inside, and a phase change magnetohydrodynamic working fluid is sealed inside the microchannel network. A magnetic field generating module is disposed on the heat exchange module and corresponds to at least a portion of the microchannel network; The processing and control module is electrically connected to the temperature sensor of the series battery pack and the magnetic field generating module. The processing and control module is configured to: based on the real-time data from the temperature sensor, control the magnetic field generation module to generate a static magnetic field or a dynamic magnetic field, so as to control the flow path of the phase change magnetohydrodynamic working fluid in the microchannel network and enhance the local convective heat transfer coefficient.

2. The dynamic thermal equilibrium control system for a series battery pack according to claim 1, characterized in that, The heat exchange module includes an integrated thermal management structure, which is a metal partition between the multiple individual cells or a metal shell of the individual cells, and the microchannel network is disposed inside the integrated thermal management structure.

3. The dynamic thermal equilibrium control system for a series battery pack according to claim 1, characterized in that, The phase-change magnetohydrodynamic working fluid is composed of an insulating dielectric liquid base with a preset phase-change temperature and magnetic nanoparticles uniformly suspended in the base liquid.

4. The dynamic thermal equilibrium control system for a series battery pack according to claim 1, characterized in that, The processing and control module is configured to identify the heat source cell and the heat target cell when it is determined that directional heat scheduling is required, and control the magnetic field generation module to generate the static magnetic field at the microchannel network on the non-target path to form local flow resistance, thereby driving the vapor phase of the phase change magnetohydrodynamic working fluid to flow along the target path from the heat source cell to the heat target cell.

5. A dynamic thermal equilibrium control system for a series battery pack according to claim 4, characterized in that, The static magnetic field generates a magnetic field force density in the phase-change magnetohydrodynamic working fluid, and this magnetic field force density forms the local flow resistance, which satisfies the following relationship: ； in, It represents the magnetic field force density; Permeability of free space; The magnetization intensity of the phase-change magnetohydrodynamic working fluid; For gradient operators; The magnetic field strength of the static magnetic field is given.

6. The dynamic thermal equilibrium control system for a series battery pack according to claim 1, characterized in that, The processing and control module is configured to, when it is determined that heat transfer enhancement is needed for a local hot spot, control the magnetic field generation module to generate the dynamic magnetic field at the microchannel network corresponding to the local hot spot, so as to drive the magnetic nanoparticles in the phase change magnetohydrodynamic working fluid to generate microscopic disturbances, thereby enhancing the convective heat transfer coefficient of the local area.

7. A dynamic thermal equilibrium control system for a series battery pack according to claim 6, characterized in that, The dynamic magnetic field applies a time-varying magnetic torque to the magnetic nanoparticles, and the magnetic torque drives the microscopic perturbation, which satisfies the following relationship: ； in, The magnetic torque acting on a single magnetic nanoparticle; Permeability of free space; The volume of a single magnetic nanoparticle; The magnetization intensity of a single magnetic nanoparticle; For cross product operators; The magnetic field strength of the dynamic magnetic field is given.

8. The dynamic thermal equilibrium control system for a series battery pack according to claim 1, characterized in that, The processing and control module is also configured to collaboratively control the magnetic field generation module when a local hot spot and a low-temperature region are detected to coexist. The static magnetic field is generated on a non-target path to construct a directional transport channel from the local hot spot to the low-temperature region, while the dynamic magnetic field is generated at the local hot spot to enhance heat transfer at that hot spot.

9. A dynamic thermal equilibrium control system for a series battery pack according to claim 1, characterized in that, The magnetic field generating module includes a micro electromagnetic array, which is integrated onto the surface of the heat exchange module via a printed circuit board or flexible circuit board.

10. A dynamic thermal equilibrium control method for a series battery pack, applied to the system described in any one of claims 1-9, characterized in that, Includes the following steps: Real-time monitoring of the temperature distribution of the series-connected battery pack; Based on the temperature distribution, it is determined whether there is a target area in the series-connected battery pack that requires targeted heat dissipation or localized heat transfer enhancement; in response to the determination that the target area exists, the micro electromagnetic array is controlled to perform a corresponding magnetic field generation operation for the target area, wherein: If the target area requires directional heat dispatch, a static magnetic field is generated to guide the flow path of the phase change magnetohydrodynamic working fluid. If the target area requires enhanced local heat transfer, a dynamic magnetic field is generated to improve the local convective heat transfer coefficient.

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