A battery thermal runaway triggering device based on infrared feedback

Abstract

The utility model relates to lithium ion battery safety test and thermal runaway technical field, concretely relates to a kind of eddy current heating formula battery thermal runaway trigger device based on infrared feedback. Including heating medium, the heating medium is attached to power battery outer surface or embedded interlayer of electric core;Heating medium is arranged with induction coil around;Induction coil is connected with power supply, and power supply exports high-frequency alternating current;Still include infrared temperature sensor, the infrared temperature sensor non-contact alignment power battery surface target point area;The infrared temperature sensor is electrically connected with central control module, and the central control module is used to receive the infrared temperature signal of infrared temperature sensor and send the output power control signal of power supply.This technical scheme can improve the accuracy of thermal runaway trigger, reduce test risk, and strong adaptability.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery safety testing and thermal runaway technology, specifically to an eddy current heating battery thermal runaway triggering device based on infrared feedback. Background Technology

[0002] As a key energy carrier for new energy vehicles and energy storage systems, power batteries have been widely used in transportation, power storage, and many other fields due to their high energy density and wide applicability. However, power batteries face complex and variable environmental conditions during operation. When encountering extreme conditions such as overcharging, high temperature, short circuit, or mechanical impact, the electrochemical reactions inside the battery can become uncontrolled, triggering a violent exothermic reaction and causing the battery temperature to rise sharply, thus triggering thermal runaway. Once thermal runaway occurs, it can easily lead to serious safety accidents such as battery fire or even explosion, causing not only huge property losses but also endangering human lives.

[0003] To delve into the mechanisms of battery thermal runaway and develop effective protection strategies, it is necessary to actively trigger the thermal runaway process of individual battery cells in a laboratory setting using appropriate methods. This approach allows for precise control of the triggering conditions, enabling the controlled reproduction of the thermal runaway process and providing reliable data support for subsequent research and analysis.

[0004] Currently, the three main methods commonly used in laboratories to trigger battery thermal runaway are resistance heating, hot air heating, and mechanical needle penetration. Both resistance heating and hot air heating rely on heat transfer processes to heat the battery; resistance heating uses contact heat transfer, while hot air heating relies on radiation heat transfer. However, these two methods have several limitations in practical applications. Firstly, they are significantly affected by thermal resistance, airflow, and environmental factors, leading to uneven battery temperature distribution and significant temperature differences in different parts, making it difficult to achieve precise control of the overall battery temperature. Secondly, these two heating methods have slow response times and significant lag, failing to achieve the preset heating effect in a timely and accurate manner. Furthermore, for pre-packaged battery packs, the compact internal space makes the equipment layout for these two heating methods difficult to implement, hindering practical research needs.

[0005] While mechanical needle penetration can rapidly trigger thermal runaway in a battery, the procedure is quite complex. Before penetration, holes need to be pre-drilled on the battery surface, increasing preparation time and potentially damaging the battery's original structure, affecting the accuracy of results. Furthermore, mechanical needle penetration requires sophisticated equipment, necessitating a high-precision needle penetration device and control system, increasing costs. Additionally, the contact between the needle and internal battery components during penetration can easily trigger secondary arcing, further increasing the experimental risk.

[0006] In recent years, eddy current (electromagnetic induction) heating technology has been gradually introduced into the field of battery thermal runaway research due to its unique advantages. Eddy current heating features non-contact operation, high efficiency, and strong local heating capability. It can generate eddy currents inside the battery through electromagnetic induction without direct contact, thereby achieving rapid heating. However, traditional eddy current heating technologies mostly adopt open-loop control, which cannot adjust the heating power in a timely manner according to the actual temperature changes of the battery during the heating process. This results in an extremely rapid temperature rise rate and severe temperature overshoot. This uncontrollable heating method can easily cause the battery to reach excessively high temperatures in a short period of time, exceeding its tolerance range. This not only fails to accurately simulate the thermal runaway process under actual working conditions but may also cause excessive damage to the battery, affecting the reliability of experimental results.

[0007] Meanwhile, in traditional battery thermal runaway triggering experiments, the commonly used contact thermocouple temperature measurement method has significant drawbacks in strong electromagnetic environments. Because the thermocouple is in direct contact with the battery, the strong electromagnetic field interferes with the thermocouple's signal transmission, causing temperature signal distortion and failing to accurately reflect the true temperature of the battery cell. This makes it difficult to obtain accurate temperature data during the battery's thermal runaway process, thus affecting in-depth analysis of the thermal runaway mechanism and the effective formulation of protection strategies.

[0008] Furthermore, different types of battery structures exhibit significant differences in their response to electromagnetic heating. Taking the common square aluminum-cased battery as an example, its thick outer shell and high conductivity provide significant shielding against magnetic fields, making it difficult for externally applied high-frequency magnetic fields to generate effective eddy currents inside the battery, thus hindering effective eddy current heating. In contrast, the outer layer of a soft-pack aluminum-plastic film battery cell is a metal / non-metal composite film. To achieve localized heating, a ferromagnetic sheet needs to be embedded inside the cell, and a high-frequency magnetic field needs to be tightly coupled to achieve the heating purpose, which increases the complexity and cost of the experiment. For battery systems using steel shells or steel enclosures, although the steel itself can act as a ferromagnetic heating medium, rapidly generating heat by applying a high-frequency magnetic field to the bottom or sidewalls, accurately controlling the heating position and power to precisely simulate the battery's thermal runaway triggering conditions remains a problem that urgently needs to be solved in practical applications. Utility Model Content

[0009] The purpose of this invention is to propose an eddy current heating battery thermal runaway triggering device based on infrared feedback. This technical solution can improve the accuracy of thermal runaway triggering, reduce experimental risks, and has strong adaptability.

[0010] To achieve the above objectives, this utility model proposes an eddy current heating battery thermal runaway triggering device based on infrared feedback, comprising a heating medium, which is attached to the outer surface of the power battery or embedded between the cell layers; an induction coil is arranged around the heating medium; the induction coil is connected to a power source, and the power source outputs a high-frequency alternating current. It also includes an infrared temperature sensor, which is non-contactly aligned with the target area on the surface of the power battery; the infrared temperature sensor is electrically connected to the central control module, which is used to receive the infrared temperature signal from the infrared temperature sensor and issue the power output control signal of the power supply.

[0011] Beneficial effects of the basic scheme: This device first uses an infrared temperature sensor to non-contactly align with the target area on the surface of the power battery, which can collect the temperature data of the target point in real time and feed it back to the central control module, avoiding the lag and temperature point offset problems of contact temperature measurement; the central control module dynamically adjusts the power output power based on the temperature feedback signal, realizing precise closed-loop control of the heating medium heating rate, ensuring that the power battery can heat up according to the preset temperature curve, effectively solving the problems of energy injection imbalance, local overheating or insufficient heating in traditional open-loop eddy current heating, greatly improving the accuracy and consistency of thermal runaway triggering, and providing accurate experimental triggering conditions for battery thermal safety assessment.

[0012] Then, a high-frequency magnetic field is generated by exciting the induction coil with a high-frequency alternating current, which causes eddy currents and hysteresis losses to be generated inside the ferromagnetic heating medium and rapidly raises the temperature. The heat can be directly conducted to the power battery through bonding or embedding. The heat conduction path is short and the heat loss is small, and the heating speed is faster than traditional resistance heating and other methods. At the same time, the closed-loop control mode can dynamically adjust the heating power according to the real-time temperature of the battery to avoid ineffective energy consumption, further shorten the experimental cycle of thermal runaway triggering and improve experimental efficiency.

[0013] The heating medium is arranged to fit the outer surface of the battery or embedded between the cell layers, eliminating the need for destructive drilling or implantation of temperature sensing / heating elements into the power battery, thus preserving the original structural state of the battery to the greatest extent. Non-contact infrared temperature measurement also avoids the obstruction or interference of contact sensors on the battery surface, and can be adapted to power batteries of different specifications and packaging forms (such as cylindrical, square, and pouch batteries), making it more widely applicable.

[0014] The central control module can also adjust the power when the temperature is too high based on the infrared temperature signal, so as to avoid problems such as overheating of the power battery and thermal runaway caused by power runaway.

[0015] Temperature closed-loop control ensures that key parameters such as heating rate and thermal runaway trigger temperature are highly consistent in each experiment, effectively improving the repeatability and comparability of experimental data; it can stably reproduce the entire process of thermal runaway of power batteries, providing high-quality experimental data support for the analysis of thermal runaway mechanism of power batteries, research on thermal propagation path, and verification of protection technology, and helping the research and optimization of related technologies.

[0016] As a feasible preferred embodiment, it also includes an explosion-proof test chamber for providing a closed test environment; the power battery, heating medium, and induction coil are located inside the explosion-proof test chamber.

[0017] As a feasible preferred embodiment, the wall of the explosion-proof test chamber is embedded with an infrared window, and the infrared temperature sensor is located outside the explosion-proof test chamber and is arranged coaxially with the infrared window.

[0018] As a feasible preferred solution, the infrared temperature sensor is connected to the central control module via a shielded signal line, and filtering and anti-interference circuits are provided.

[0019] As a feasible and preferred option, the walls of the explosion-proof test chamber are equipped with observation windows.

[0020] As a feasible preferred option, the heating medium is a thin ferromagnetic material, which is one of low carbon steel, silicon steel or iron-nickel alloy.

[0021] As a feasible preferred option, the induction coil adopts a hollow copper tube structure with cooling water flowing inside.

[0022] As a feasible preferred embodiment, the cooling water inlet and outlet of the induction coil are respectively connected to the cooling water tank through insulated pipes, and the cooling water tank and the refrigeration unit form a circulating cooling loop.

[0023] As a feasible preferred embodiment, the device also includes a temperature and humidity control device, which includes a fan and is located outside the explosion-proof test chamber, connected to the explosion-proof test chamber via an air inlet pipe and an exhaust pipe.

[0024] As a feasible preferred solution, a data acquisition module is also included, which is used to synchronously acquire the current, voltage, temperature and power curves of the induction coil through current sensors and voltage sensors. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the device of this utility model.

[0026] Figure 2 This is a schematic diagram of the eddy current heating principle of this utility model.

[0027] Figure 3 This is a schematic diagram of the eddy current heating thermal runaway triggering process of this utility model.

[0028] Figure reference numerals: 1. Explosion-proof test chamber; 21. Induction coil; 22. Heating medium; 23. Power battery; 31. Cooling water tank; 35. Refrigeration unit; 34. Temperature and humidity control device; 4. Observation window; 41. Infrared window; 42. Infrared temperature sensor; 51. Central control module; 52. Power supply; 53. Data acquisition module; 54. Current sensor; 55. Voltage sensor. Detailed Implementation

[0029] To make the technical solution and advantages of this application clearer, the technical solution of this utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this utility model, and are only used to explain this application, not to limit it. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated; they can be combined with each other to achieve better technical effects. The same reference numerals appearing in the accompanying drawings of the following embodiments represent the same features or components, and can be applied to different embodiments.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection (including various forms of mechanical connection, such as couplings or gear pairs), or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] Furthermore, unless otherwise defined, the technical or scientific terms used in this description shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0032] The present invention will now be described in further detail with reference to the accompanying drawings: Reference Figure 1An eddy current heating battery thermal runaway triggering device based on infrared feedback includes an explosion-proof test chamber 1, a central control module 51, a cooling water tank 31, a refrigeration unit 35, a temperature and humidity control device 34, an induction coil 21, a heating medium 22, a power battery 23, an observation window 4, an infrared window 41, an infrared temperature sensor 42, a power supply 52, a current sensor 54, a voltage sensor 55, and a data acquisition module 53.

[0033] The explosion-proof test chamber 1 is used to provide a safe and enclosed experimental environment to prevent fires or explosions that may occur during thermal runaway from harming experimental personnel and the environment.

[0034] The explosion-proof test chamber 1 is located on the outermost layer of the device. The power battery 23 to be tested is placed inside. The chamber is connected to the refrigeration unit 35 via cooling pipes. A water-cooled induction coil 21 and a heating medium 22 are installed inside. In this embodiment, a pouch battery is used as an example. The outer layer of this structure is an aluminum-plastic film, which facilitates magnetic field coupling. The heating medium can be fitted into the inside of the battery cell to achieve efficient localized heating. For square aluminum-cased cells or steel-cased structures, the relative positions of the induction coil and the ferromagnetic medium can be adjusted according to the characteristics of the casing material to achieve the same eddy current heating and infrared feedback control functions.

[0035] Reference Figure 2 The induction coil 21 is tightly arranged around the heating medium 22, without any aluminum, copper, or other metal shielding layer between them. The power supply 52 is connected to the water-cooled induction coil 21 via a cable, providing it with alternating current to generate a high-frequency magnetic field. This magnetic field induces eddy currents and hysteresis losses within the heating medium 22, resulting in rapid heating. The heat is transferred to the outer surface of the power battery 23 via thermal conductivity, achieving rapid and tight heating of the internal components. In this embodiment, the power supply 52 is a high-frequency induction heating power supply, specifically the SP-15A or a similar high-frequency induction heating device. Its main technical parameters are: rated input voltage AC220V, output oscillation power 15kW - 25kW, and output oscillation frequency range 30kHz - 100kHz.

[0036] The induction coil 21 adopts a hollow copper tube structure with cooling water flowing inside to stabilize the magnetic field and temperature.

[0037] The cooling water tank 31 and the refrigeration unit 35 form a circulating cooling circuit to continuously dissipate heat from the induction coil 21 and the heating medium 22; the refrigeration unit 35 includes a compressor and a circulating pump.

[0038] The temperature and humidity control device 34 is used to regulate the environment inside the test chamber, ensuring experimental stability and safety, and guaranteeing the consistency of the experimental environment. Specifically, the temperature and humidity control device is located outside the explosion-proof test chamber 1 and is connected to the explosion-proof test chamber 1 through air inlet and exhaust pipes. The temperature and humidity control device monitors environmental data in real time through sensors installed inside the chamber and feeds it back to the central control module 51. When the temperature or humidity inside the chamber deviates from the preset value, the central control module 51 controls the temperature and humidity control device 34 to start the circulating fan, extracting the gas inside the chamber, dehumidifying or heating it, and then returning it to the chamber, forming a closed-loop control to ensure the consistency of the experimental environment. The ambient temperature or humidity inside the test chamber can be adjusted by the fan.

[0039] The heating medium 22 is a thin ferromagnetic material (such as low carbon steel, silicon steel or iron-nickel alloy) with a thickness of 0.1-0.5mm. It can be attached to the outer surface of the battery or embedded between the cell layers and is suitable for batteries with different structures (soft-pack cells, steel-cased cells or steel box structures).

[0040] The observation window 4 is set on the wall of the explosion-proof test chamber 1 to observe the test conditions inside the explosion-proof test chamber 1.

[0041] Infrared window 41 is located on the wall of explosion-proof test chamber 1 and is made of a material with high infrared transmittance and electromagnetic shielding performance (such as zinc selenide, germanium, or sapphire glass) to ensure accurate transmission of infrared signals while preventing electromagnetic interference. Infrared temperature sensor is installed outside the explosion-proof chamber and arranged coaxially with the window, and is fixed by insulating clamps to ensure a constant gap between the coil and the heating medium, thereby improving experimental repeatability and safety.

[0042] The infrared temperature sensor 42 is aligned with the target area on the battery surface through the infrared window 41 on the housing wall, receives infrared radiation signals in real time, obtains temperature data after signal amplification and digital processing, and transmits it to the central control module 51.

[0043] The central control module 51 is the core control hub of this device, and in this embodiment, it is implemented using an industrial control computer (IPC) or a host computer system equipped with control software. The central control module 51 is communicatively connected to the power supply 52, the infrared temperature sensor 42, and the data acquisition module 53. Its internal logic includes a signal acquisition unit, a data filtering unit, a PID control unit, and a safety logic unit. The central control module 51 takes the deviation between the real-time temperature signal fed back by the infrared temperature sensor 42 and the set trigger temperature as input, executes a PID closed-loop algorithm within the software, and sends power adjustment commands to the power supply 52 through the communication interface.

[0044] In this embodiment, the core processing unit of the central control module 51 uses an STM32F407ZGT6 microcontroller. This chip has a main frequency of 168MHz, peripheral interfaces, and a floating-point arithmetic unit, enabling it to quickly process high-frequency sampling data from the infrared temperature sensor and run a PID closed-loop control algorithm to output PWM signals in real time to adjust the power supply.

[0045] The infrared temperature sensor is connected to the central control module 51 via a shielded signal line, and filtering and anti-interference circuits are set up to ensure the accuracy of the temperature measurement signal under high-frequency magnetic field.

[0046] The central control module 51 includes a signal acquisition unit, a data filtering unit, a PID control unit, and a safety logic unit 3. The central control module 51 takes the deviation between the infrared temperature signal and the set trigger temperature as input, executes a PID closed-loop algorithm, and outputs a control signal for the output power of the dynamically adjustable power supply 52: when the temperature approaches the threshold, it automatically limits the power to prevent overshoot; when the temperature reaches the set value and the temperature rise rate or voltage drop meets the trigger conditions, the system immediately cuts off the power and records the trigger data.

[0047] Referring to Figure 2, the induction coil 1 and the heating medium constitute the core of energy conversion. The high-frequency magnetic field induces eddy currents and hysteresis losses in the medium, causing its surface to generate a large amount of heat in a short time. Because the coil is tightly attached to the medium and there is no metal shielding, the magnetic field energy utilization rate is extremely high, and the heating rate is much faster than resistance or hot air heating. Compared with traditional contact heating, this embodiment can significantly shorten the triggering time and ensure temperature uniformity.

[0048] Referring to Figure 3, the system's workflow includes five stages: initialization, heating, monitoring, judgment, and power-off. After startup, the system completes temperature and humidity regulation and pre-start of the cooling cycle; subsequently, power supply 52 excites coil 21, and infrared sensor 42 begins monitoring the temperature. The control module adjusts the power based on temperature feedback to stabilize the temperature rise rate. When the temperature reaches the set threshold or triggers characteristics such as a sudden voltage drop or abnormal temperature rise rate occur, the system automatically stops heating and records experimental data; if the conditions are not met, heating continues until the trigger is completed. Data acquisition module 53 synchronously records current, voltage, temperature, and power curves, providing data support for subsequent analysis.

[0049] The working principle of this embodiment is as follows: Under the action of a high-frequency magnetic field, eddy currents and hysteresis losses are generated in the heating medium 22, and the temperature rises rapidly, transferring heat to the power battery 23; the infrared temperature sensor 42 provides real-time feedback, and the central control module 51 realizes closed-loop power regulation. This method effectively overcomes the problems of temperature response lag, energy injection imbalance, and uncontrollable overheating that exist in traditional contact or open-loop eddy current heating, while having the advantages of faster heating, more stable control, and higher repeatability. Combined with a cooling and environmental conditioning system, the experimental process can be ensured to be safe and reliable, providing a high-precision experimental platform for the thermal safety assessment and propagation mechanism research of power batteries.

[0050] The above content is merely an embodiment of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can improve and implement this solution based on the guidance provided in this application and their own capabilities. Typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model. These should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A thermal runaway triggering device for a battery based on infrared feedback and eddy current heating, characterized in that: The battery includes a heating medium that is attached to the outer surface of the power battery or embedded between the cell layers; an induction coil is arranged around the heating medium; the induction coil is connected to a power source that outputs a high-frequency alternating current. It also includes an infrared temperature sensor, which is non-contactly aligned with the target area on the surface of the power battery; the infrared temperature sensor is electrically connected to the central control module, which is used to receive the infrared temperature signal from the infrared temperature sensor and issue the power output control signal of the power supply.

2. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: It also includes an explosion-proof test chamber to provide a closed test environment; the power battery, heating medium, and induction coil are located inside the explosion-proof test chamber.

3. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 2, characterized in that: The explosion-proof test chamber has an infrared window embedded in its wall, and the infrared temperature sensor is located outside the explosion-proof test chamber and is arranged coaxially with the infrared window.

4. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: The infrared temperature sensor is connected to the central control module via a shielded signal line, and filtering and anti-interference circuits are provided.

5. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: The walls of the explosion-proof test chamber are fitted with observation windows.

6. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: The heating medium is a thin ferromagnetic material, made of one of the following: low-carbon steel, silicon steel, or iron-nickel alloy.

7. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: The induction coil uses a hollow copper tube structure with cooling water flowing inside.

8. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: The cooling water inlet and outlet of the induction coil are connected to the cooling water tank through insulated pipes, and the cooling water tank and the refrigeration unit form a circulating cooling loop.

9. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: It also includes a temperature and humidity control device, which includes a fan. The temperature and humidity control device is located outside the explosion-proof test chamber and is connected to the explosion-proof test chamber through an air inlet pipe and an exhaust pipe.

10. The eddy current heating battery thermal runaway triggering device based on infrared feedback according to claim 1, characterized in that: It also includes a data acquisition module, which is used to synchronously acquire the current, voltage, temperature and power curves of the induction coil through current sensors and voltage sensors.

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