Multi-stage cooperative safety protection system for power battery with built-in self-heating function

Abstract

The application provides a kind of inbuilt self-heating function power battery multistage collaborative safety protection system, the system includes battery cell, and the physical connection of battery cell is electrically isolated protection module and structure sealing protection module and the electrical connection of battery cell is hardware loop fuse protection module, software strategy temperature control protection module and whole vehicle linkage safety protection module, battery cell includes self-heating battery pole piece and self-heating battery pole piece is built-in electric heating conversion layer, electric heating conversion layer is used to connect with power supply and carry out electric heating conversion when power on.The application realizes the full cycle, multidimensional safety protection of pole piece self-heating process through the collaborative cooperation of four levels of protection modules of structure, hardware, software and whole vehicle, completely avoids heating short circuit, over-temperature, string voltage, electrolyte corrosion and other safety hazards, meets the demand of national mandatory safety standards and actual operation scene.

Description

Technical Field

[0001] This invention relates to the field of power battery thermal safety protection technology, and in particular to a multi-level collaborative safety protection system for power batteries with built-in self-heating function. Background Technology

[0002] Power batteries are the core power supply unit of new energy equipment. Their low temperature adaptability is the core bottleneck restricting their application in extremely cold scenarios: In low temperature environments of -20℃ and below, the viscosity of the battery electrolyte increases significantly, the ionic conductivity decreases sharply, and the polarization reaction intensifies. This not only leads to a significant reduction in driving range, but also makes it easier to induce lithium dendrite growth during low temperature charging, which can puncture the separator and cause internal short circuits, posing a risk of thermal runaway.

[0003] To address the challenges of low-temperature start-up and operation of power batteries, the industry is gradually promoting self-heating technology. Unlike the inefficient external heating mode of traditional PTC, self-heating technology generates heat directly inside the battery cell by setting up an electrothermal conversion unit inside the cell after power is applied. It has advantages such as fast heating speed, good temperature uniformity, and high energy utilization rate, and has now become a key direction for industry research and development and industrialization.

[0004] The current mainstream self-heating solution for battery electrodes involves composite electrothermal conversion layers inside the battery electrode substrate, with heating achieved through an external control circuit. However, this structure inherently presents multiple safety hazards, and existing technologies have not developed a system-level collaborative protection solution. ① Risk of series voltage and short circuit in the circuit: The heating circuit and the main energy storage circuit are both located inside the cell. The existing technology does not provide mandatory physical isolation. The two circuits are prone to series voltage and short circuit due to insulation aging and electrode displacement, which can directly induce thermal runaway of the cell. ② Risk of electrothermal conversion layer erosion failure: The power battery is a sealed liquid-immersed structure with organic electrolyte inside the cell. The existing heating electrode mostly adopts a simple sealed structure with an insulating layer coated on one side. During long-term charge and discharge cycles, the electrolyte can easily erode the electrothermal conversion layer through the micropores and edge gaps of the coating, resulting in heating power attenuation, internal insulation damage, and causing continuous safety hazards. ③ Single protection method without coordination: The existing self-heating system only has independent hardware overcurrent protection or software over-temperature protection, and has not formed a multi-level coordinated protection mechanism of structure-hardware-software-vehicle, resulting in protection blind spots: simple hardware protection has no predictive ability, and simple software protection relies on power supply and signal transmission. Once special working conditions such as signal interruption or relay sintering occur, the protection mechanism will fail. ④ Insufficient full-condition monitoring coverage: Existing technology lacks real-time monitoring methods for heating circuit leakage, abnormal heating of single cells, low-temperature heating deformation and expansion, and long-term aging of the heating layer. Furthermore, it has not formed a linkage control with the vehicle controller and battery fire protection system, making it impossible to quickly handle faults. This does not meet the latest mandatory standard requirements for thermal runaway protection in GB38031-2025 "Safety Requirements for Power Batteries for Electric Vehicles".

[0005] Currently available self-heating battery technologies can only achieve basic heating control and lack multi-level collaborative protection schemes to address the specific safety hazards of the built-in heating structure of the electrodes. They cannot balance low-temperature heating efficiency with safety protection under all operating conditions. Especially in dangerous scenarios such as insulation failure in the heating circuit, electrolyte erosion of the heating layer, and excessive cell expansion due to abnormal heating, existing technologies lack system-level protection capabilities for multi-dimensional prediction, active disconnection, and fault isolation. Therefore, their safety protection reliability cannot meet the needs of industrialization. Summary of the Invention

[0006] This invention provides a multi-level collaborative safety protection system for power batteries with built-in self-heating function to solve one or more technical problems encountered in the prior art.

[0007] In a first aspect, the present invention provides a multi-level collaborative safety protection system for a power battery with built-in self-heating function, including a battery cell, an electrical isolation protection module and a structural sealing protection module physically connected to the battery cell, and a hardware circuit fuse protection module, a software strategy temperature control protection module and a vehicle linkage safety protection module electrically connected to the battery cell. The battery cell includes a self-heating battery electrode and the self-heating battery electrode has a built-in electrothermal conversion layer. The electrothermal conversion layer is used to connect to the power supply and perform electrothermal conversion when energized. It realizes safe operation protection of the built-in self-heating battery electrode under all working conditions from multiple dimensions, avoiding safety hazards such as heating short circuit, overheating, voltage leakage and electrolyte corrosion.

[0008] In a preferred embodiment, the electrical isolation protection module is used to physically isolate the energy storage circuit of the battery cell from the heating circuit.

[0009] In a preferred embodiment, the structural sealing protection module uses a multi-layer thermo-pressurized sealing structure to isolate the internal electrothermal conversion layer from electrolyte corrosion.

[0010] In a preferred embodiment, the hardware circuit fuse protection module integrates overcurrent protection, over-temperature power-off protection, and short-circuit self-locking protection devices.

[0011] In a preferred embodiment, the software strategy temperature control protection module is used to set the maximum temperature rise rate limit and the extreme temperature cut-off threshold of the battery cell.

[0012] In a preferred embodiment, the vehicle-wide safety protection module includes real-time monitoring of leakage current in the heating circuit and a rapid power-off function.

[0013] In a preferred embodiment, the vehicle-wide safety protection module includes functions for independent identification of single-cell heating faults and isolation and control of faulty cells.

[0014] In a preferred embodiment, during the low-temperature heating operation, the vehicle-wide safety protection module includes synchronous monitoring of the battery cell expansion and deformation status.

[0015] In a preferred embodiment, the vehicle-linked safety protection module is linked to the battery pack fire alarm device to provide early warning of impending thermal runaway; when the heating circuit malfunctions, the vehicle-linked safety protection module automatically switches to a pure energy storage safety operating mode.

[0016] In a preferred embodiment, the vehicle-wide safety protection module includes an online monitoring and early warning function for the aging status of the heating layer under long-term cyclic operating conditions.

[0017] One of the above technical solutions has the following advantages or beneficial effects: (1) Dual structure isolation to block primary safety hazards from the root: On the one hand, the energy storage circuit and the heating circuit are hard isolated by the electrical isolation protection module to completely avoid the risk of series voltage and cross short circuit; on the other hand, the electrothermal conversion layer is isolated from the electrolyte by the multi-layer hot-press sealing structure to completely eliminate the heating layer failure and internal short circuit hazards caused by electrolyte corrosion, and improve the long-term cycle reliability of the self-heating structure. (2) Three-level circuit protection to achieve rapid fault handling: The hardware circuit fuse protection module serves as a backup hard protection, with a response speed faster than the software protection; the software strategy temperature control protection module achieves precise process control. The two, together with the remote protection command of the vehicle linkage module, form a three-level protection mechanism, which takes graded actions under different fault levels to completely avoid the risks of over-temperature, overcurrent, and short circuit. (3) Full-condition multi-dimensional monitoring and system-level collaborative risk prediction: The vehicle linkage safety protection module covers the full-dimensional monitoring of leakage, deformation, single cell failure, heating layer aging, and thermal runaway precursors during the heating process. It is linked with the vehicle and fire protection system in real time, and can identify fault signs before danger occurs and take measures in advance. It meets the latest mandatory standard of GB38031-2025 "Safety Requirements for Power Batteries for Electric Vehicles" that "no fire or explosion within 2 hours after thermal runaway". (4) Flexible handling of faults to ensure basic operation capability: After the heating circuit fails, the system does not directly cut off the entire battery circuit, but automatically switches to pure energy storage safety working mode to retain the basic functions of normal charging and discharging of the battery and avoid secondary safety accidents such as unexpected power outages and breakdowns during vehicle operation. (5) Multi-level protection coordination to eliminate protection blind spots: The four levels of protection modules, namely structural, hardware, software and vehicle, do not operate independently, but form a linkage closed loop control through the BMS main control unit. Under different operating conditions, protection actions are performed in coordination according to the fault level, which completely eliminates the protection blind spots of a single protection scheme and comprehensively improves the safety protection level of the built-in self-heating battery under all operating conditions.

[0018] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0019] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in the invention and should not be construed as limiting the scope of the invention.

[0020] Figure 1 This is a schematic diagram of the overall structure and connection of the intelligent temperature-controlled self-heating battery in this embodiment. Detailed Implementation

[0021] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0022] This embodiment provides a multi-level collaborative safety protection system for a power battery with built-in self-heating function. (See also...) Figure 1 As shown, the safety protection system includes a battery cell 100, an electrical isolation protection module 130 and a structural sealing protection module 140 physically connected to the battery cell 100, and a hardware circuit fuse protection module 150, a software strategy temperature control protection module 160 and a vehicle linkage safety protection module 170 electrically connected to the battery cell 100. The battery cell 100 includes a self-heating battery electrode 120, and the self-heating battery electrode 120 has a built-in electrothermal conversion layer. The electrothermal conversion layer is connected to an external control power supply through a dedicated heating electrode column. When energized, it efficiently converts electrical energy into heat energy, directly heating the battery cell 100 body internally. This solves the problems of insufficient activity of active materials and low conductivity of electrolyte under low temperature conditions, and achieves full-condition safe operation protection of the built-in self-heating battery electrode 120 from multiple dimensions, avoiding safety hazards such as heating short circuit, overheating, voltage leakage, and electrolyte corrosion.

[0023] In one specific embodiment, the electrical isolation protection module 130 is used to physically isolate the energy storage circuit and the heating circuit of the battery cell 100. Located at the connection points of the internal and external circuits of the battery cell 100, it completely physically isolates the main energy storage circuit of the cell from the heating circuit, structurally eliminating the risk of voltage surges, insulation breakdown, and cross-short circuits between the two circuits.

[0024] In one specific embodiment, the structural sealing protection module 140 uses a multi-layer thermo-pressed sealing structure to isolate the internal electrothermal conversion layer from electrolyte corrosion. The multi-layer thermo-pressed composite sealing structure completely encloses the electrothermal conversion layer within the self-heating electrode 120. The edges of the sealing structure are sealed using a high-temperature thermo-pressing process, completely isolating the electrothermal conversion layer from the electrolyte inside the battery cell and ambient moisture, thus preventing electrolyte corrosion of the electrothermal conversion layer from causing insulation failure and heating power attenuation.

[0025] In one specific embodiment, the hardware circuit fuse protection module 150 integrates overcurrent protection, over-temperature power-off, and short-circuit self-locking protection devices. Arranged in series in the power supply trunk of the heating circuit, it integrates three independent protection devices: an overcurrent protection fuse, an over-temperature power-off temperature control switch, and a short-circuit self-locking protection relay. In the event of heating overcurrent, circuit over-temperature, or short-circuit faults, it directly and quickly cuts off the heating circuit at the hardware level without relying on any external control signals, serving as the first line of passive safety protection.

[0026] In one specific embodiment, the software strategy temperature control and protection module 160 is used to set the maximum temperature rise rate limit and the extreme temperature cutoff threshold of the battery cell. Integrated in the main control and computing unit of the battery management system (BMS), it has two types of core safety control parameters pre-calibrated: the maximum temperature rise rate limit and the extreme temperature cutoff threshold of the battery cell. It collects data on the operating current of the heating circuit, the surface temperature of the battery cell, and the internal temperature of the battery cell in real time, and performs closed-loop control of the heating process. When the measured data reaches the preset threshold, it actively issues a cutoff command, serving as the core control unit for active safety protection.

[0027] In one specific embodiment, the vehicle-linked safety protection module 170 includes real-time monitoring of leakage current in the heating circuit and rapid power-off disconnection function.

[0028] In one specific embodiment, the vehicle-wide safety protection module 170 includes functions for independent identification of single-cell heating faults and isolation and control of faulty cells.

[0029] In one specific embodiment, during the low-temperature heating operation, the vehicle linkage safety protection module 170 includes synchronously monitoring the expansion and deformation state of the battery cell 100.

[0030] In one specific embodiment, the vehicle-linked safety protection module 170 is linked to the battery pack fire alarm device to provide early warning of impending thermal runaway; when the heating circuit fails, the vehicle-linked safety protection module 140 is used to automatically switch to a pure energy storage safety working mode.

[0031] In one specific embodiment, the vehicle-linked safety protection module 170 includes an online monitoring and early warning function for the aging status of the heating layer under long-term cyclic operating conditions.

[0032] The vehicle-wide integrated safety protection module 170 uses the BMS as its main control core and establishes a signal interaction link with the vehicle controller (VCU), battery pack fire alarm device, and multi-dimensional sensor group. It integrates six sub-functions: ① real-time monitoring and rapid power-off of heating circuit leakage; ② independent identification and isolation management of single cell heating faults; ③ synchronous monitoring of cell expansion and deformation under low temperature heating conditions; ④ linkage with the battery pack fire alarm device to achieve early warning of thermal runaway precursors; ⑤ automatic switching to pure energy storage safety working mode when the heating circuit fails; ⑥ online monitoring and early warning of heating layer aging under long-term cyclic conditions, realizing system-level fault prediction, emergency response, and risk isolation.

[0033] like Figure 1 As shown, this invention comprises six core components: a battery cell 100, an electrical isolation protection module 130, a structural sealing protection module 140, a hardware circuit fuse protection module 150, a software strategy temperature control protection module 160, and a vehicle-wide linkage safety protection module 170. The assembly and connection relationships of each module strictly distinguish between physical connections and electrical connections, fully complying with the claims. (1) Assembly of battery cell 100 with physical connection module: The battery cell 100 is the core functional unit of the system, which contains a self-heating battery electrode. The self-heating battery electrode uses a traditional lithium iron phosphate / ternary lithium electrode as the electrode substrate. An electrothermal conversion layer is embedded in the center of the electrode substrate. The electrothermal conversion layer is made of nickel-chromium alloy foil, graphene conductive coating or other materials with stable resistivity and high electrothermal conversion efficiency. It is connected to the external control power supply through a dedicated heating circuit terminal on the electrode. The energy storage circuit outputs power to the outside through an independent energy storage circuit terminal. Sufficient safety insulation distance is maintained between the two terminals.

[0034] The electrical isolation protection module 130 is physically connected to the battery cell 100.

[0035] Specific embodiments include: an insulating isolation plate is provided inside the cell between the current collector of the energy storage circuit and the electrothermal conversion layer of the heating circuit; at the circuit connection outside the cell, an insulating sealing gasket is used to physically isolate the energy storage circuit terminal and the heating circuit terminal, and the external wiring harnesses of the two circuits are respectively wrapped with insulating flame-retardant sleeves and fixed on independent mounting brackets inside the battery pack, without any physical contact, thus achieving complete physical isolation between the two circuits.

[0036] The structural sealing and protection module 140 is physically connected to the battery cell 100. Specific embodiments include: employing a three-layer hot-pressed composite sealing structure to completely encapsulate the electrothermal conversion layer. The first hot-pressed insulating sealing layer is a polyimide insulating layer, directly bonded to the upper and lower surfaces of the electrothermal conversion layer, providing basic insulation and sealing performance. The second corrosion-resistant sealing layer is a fluororubber composite layer, covering the outside of the first hot-pressed insulating sealing layer, possessing resistance to organic electrolyte corrosion and high / low temperature aging. The third structural reinforcement sealing layer is a polypropylene fiber composite layer, covering the outside of the second corrosion-resistant sealing layer, enhancing the overall mechanical strength of the sealing structure. The edges of the three layers are sealed together using a high-temperature hot-pressing process, completely enclosing the electrothermal conversion layer within the sealed structure, preventing electrolyte from eroding the electrothermal conversion layer from the electrode edges and coating gaps.

[0037] (2) Electrical connection module circuit layout: The hardware circuit fuse protection module 150 is arranged in series in the power supply trunk of the heating circuit and is electrically connected to the battery cell 100.

[0038] Specific embodiments include: the module integrates three independent protection devices: an overcurrent protection fuse, an over-temperature power-off temperature control switch, and a short-circuit self-locking protection relay; the rated current of the overcurrent protection fuse is calibrated according to the rated operating current of the heating circuit, and is generally set to 1.2-1.5 times the rated current; the over-temperature power-off temperature control switch is a normally open type temperature control switch, attached to the outer surface of the battery cell 100, and the operating temperature threshold is set to 60℃-65℃; the short-circuit self-locking protection relay is a normally closed type self-locking relay, with the coil end connected to the control circuit. The three protection devices work in series to directly cut off the heating circuit when a fault occurs.

[0039] The software strategy temperature control protection module 160 is integrated into the storage and computing unit of the BMS main control unit. It is electrically connected to the battery cell 100 and the hardware circuit fuse protection module 150 through the acquisition harness. It collects the working current of the heating circuit, the surface temperature of the cell, and the internal temperature of the cell in real time, and outputs control signals according to the preset control threshold.

[0040] The vehicle-wide safety protection module 170, with the BMS main control unit as its core, is electrically connected to the battery cell 100, the hardware circuit fuse protection module 140, and the software strategy temperature control protection module 150. It also interacts with the vehicle controller (VCU) and the battery pack fire alarm device via the CAN / LIN communication bus. The heating circuit leakage sensor is located at the grounding terminal of the heating circuit. The cell deformation monitoring sensor adopts a micro-stroke contact sensor, which is attached to the side of the battery cell 100 at the position of maximum expansion displacement. The signal output terminals of all sensors are connected to the BMS main control unit to realize multi-dimensional data acquisition and linkage control.

[0041] (1) Electrical isolation protection module 130: strictly isolates the energy storage circuit and heating circuit of the battery cell 100. The two circuits have no electrical connection or direct contact path, thus completely avoiding the risk of voltage leakage, insulation breakdown and cross short circuit between the two circuits from the structural level. (2) Structural sealing protection module 140: Through a three-layer hot-pressed composite sealing structure, the electrothermal conversion layer is completely isolated from the electrolyte inside the battery cell and the external environment moisture, so as to prevent the electrolyte from seeping into the electrode plate and eroding the electrothermal conversion layer during long-term cycling, and to prevent the insulation failure of the heating layer and the attenuation of heating power. (3) Hardware circuit fuse protection module 150: The three integrated protection devices work independently and do not rely on any external control signals: When an overcurrent fault occurs in the heating circuit, the fuse of the overcurrent protection fuse melts quickly to cut off the circuit; when the surface temperature of the battery cell touches the action threshold of the over-temperature power-off temperature control switch, the switch is passively disconnected; when a short circuit fault occurs in the circuit, the short circuit self-locking protection relay locks the circuit instantly to achieve hardware-level fast protection; (4) Software strategy temperature control protection module 160: The maximum temperature rise rate limit of the battery cell (generally set to 3-5℃ / min) and the extreme temperature cut-off threshold (generally set to 55-60℃) are pre-calibrated in the BMS. The working current and battery cell temperature data of the heating circuit are collected in real time, and the actual temperature rise rate is calculated. When the measured data is close to or touches the preset threshold, the BMS actively sends a cut-off command to the hardware circuit fuse protection module 150 to accurately control the heating process and avoid excessive temperature rise and temperature exceeding the standard. (5) Vehicle-wide safety protection module 170: The BMS main control unit coordinates and processes multi-dimensional sensor data and executes six sub-functions: ① Real-time monitoring and rapid power-off function for leakage current in heating circuit: The leakage current sensor in heating circuit collects leakage current data of the circuit in real time. When the leakage current exceeds the safety threshold (generally 10mA), the BMS sends a signal within 10ms to cut off the short-circuit self-locking protection relay and quickly disconnect the heating circuit. ②Independent identification and isolation control of heating faults in a single cell: Each 100-cell heating circuit is equipped with an independent current acquisition terminal. The BMS independently monitors the heating current of each cell. When the heating current of a cell deviates abnormally from the calibration range, it is determined that the cell has a heating fault. The heating circuit of the cell is cut off separately, while the other normal cells continue to perform heating work to avoid overall failure. ③ Synchronous monitoring of battery cell expansion and deformation during low-temperature heating operation: The cell deformation monitoring sensor collects the thickness expansion data of the cell in real time during the heating process, calculates the actual expansion rate, and when the expansion rate exceeds the preset safety value (generally 5%), the BMS immediately issues an instruction to gradually reduce the heating power and, if necessary, directly cut off the heating circuit to prevent excessive expansion of the cell from causing damage to the internal structure. ④ Linking the battery pack fire alarm device to achieve early warning of thermal runaway precursors: The BMS and the battery pack fire alarm device interact in real time. The fire alarm device integrates three types of sensors: smoke detector, combustible gas detector, and temperature detector. When it collects data of thermal runaway precursors (such as combustible gas concentration exceeding the standard or temperature rising rapidly), the BMS immediately cuts off the heating circuit and uploads the fault signal to the vehicle controller. The alarm is then triggered at the vehicle instrument level to prompt the driver to take safe measures. ⑤ Automatic switch to pure energy storage safe working mode when heating circuit fails: When the system identifies irreversible faults such as leakage, short circuit, overheating, or aging of the heating circuit, it does not directly cut off all battery circuits, but only disconnects the heating circuit, retains the normal working capability of the battery energy storage main circuit, and switches to the normal pure energy storage mode to ensure that the vehicle can be safely driven to the repair area and avoid secondary safety accidents. ⑥ Online monitoring and early warning function for the aging status of the heating layer under long-term cyclic operating conditions: During each heating operation, the BMS records the actual resistance value, electrothermal conversion efficiency, and temperature rise rate of the heating circuit in real time, and compares and analyzes them with the initial calibration data of the battery cell; when the heating circuit resistance rises by more than 20% or the electrothermal conversion efficiency drops by more than 15%, it is determined that there is a risk of aging failure of the electrothermal conversion layer. The system issues a maintenance warning in advance at the vehicle end, prompting the user to carry out timely inspection and replacement to avoid further expansion of the fault.

[0042] The four-level protection modules of this invention do not operate independently, but form a collaborative protection closed loop from the structural level to the hardware level, software level, and vehicle level, covering all operating conditions of the battery. The collaborative workflow under typical operating conditions is as follows: (1) Low-temperature cold start heating condition: When the vehicle controller detects that the battery temperature is lower than the preset low temperature start threshold (generally below 0℃), it sends a self-heating start command to the BMS. The BMS first confirms that the isolation status between the energy storage circuit and the heating circuit is normal through the electrical isolation protection module 130, and then closes the short-circuit self-locking protection relay to connect the power supply of the heating circuit. The electrothermal conversion layer generates heat when energized, which heats the cells internally. During the heating process, the structural sealing protection module continuously isolates the electrolyte, protecting the electrothermal conversion layer from corrosion; the software strategy temperature control protection module 160 monitors the temperature rise rate and cell temperature in real time, keeping them within a safe range; the hardware circuit fuse protection module 150 serves as backup protection, constantly monitoring; the vehicle linkage safety protection module 170 synchronously collects leakage current, cell expansion deformation, and heating circuit resistance data to analyze the operating status from multiple dimensions; when the battery temperature rises to the preset operating temperature range (generally 25-40℃), the BMS automatically cuts off the heating circuit, ending the heating process.

[0043] (2) Emergency protection conditions: If an abnormality occurs during the heating process, the system will execute protective actions in a coordinated manner according to the fault level: Level 1 fault (minor overcurrent, minor overtemperature): The software strategy temperature control protection module 160 will first actively reduce the heating power and reduce the heating current. If the data returns to normal, the system will maintain the collaborative monitoring state. Level 2 fault (overcurrent, overtemperature, excessive cell expansion): If the software control is ineffective and the measured data continues to reach a higher threshold, the overtemperature power-off temperature control switch or overcurrent protection fuse of the hardware circuit fuse protection module 150 will be passively activated, directly cutting off the heating circuit. At the same time, the BMS will upload the fault signal to the vehicle controller. Level 3 fault (short circuit, severe leakage, precursor to thermal runaway): After the vehicle linkage safety protection module 170 detects a severe fault, it immediately sends a cut-off command to the hardware circuit fuse protection module 150. The short circuit self-locking protection relay quickly disconnects and locks the circuit. At the same time, the BMS linkage battery pack fire alarm device issues an audible and visual alarm signal, switches the battery system to a pure energy storage safety working mode, limits the battery charging and discharging power, and minimizes the risk.

[0044] (3) Long-term cyclic aging monitoring conditions: During long-term battery use, the vehicle-linked safety protection module 170 will automatically compare and analyze the heating circuit resistance value, temperature rise rate, and heating efficiency data of this heating operation with historical data after each heating operation to determine the aging trend of the electrothermal conversion layer. When the aging degree reaches the preset warning threshold, the system will issue a maintenance reminder in advance through the vehicle instrument panel, and the user can complete the inspection and replacement in time to avoid aging failures from inducing further safety accidents.

[0045] This invention effectively solves the safety defects of existing built-in self-heating power batteries through the coordinated operation of multi-level protection modules. While achieving rapid internal heating of the battery cell and ensuring low-temperature operation performance, it comprehensively covers the safety protection requirements under all working conditions and has high industrial application value.

[0046] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-level collaborative safety protection system for a power battery with built-in self-heating function, characterized in that, It includes a battery cell, an electrical isolation protection module and a structural sealing protection module physically connected to the battery cell, and a hardware circuit fuse protection module, a software strategy temperature control protection module and a vehicle linkage safety protection module electrically connected to the battery cell. The battery cell includes a self-heating battery electrode with a built-in electrothermal conversion layer. The electrothermal conversion layer is used to connect to the power supply and perform electrothermal conversion when energized. It realizes safe operation protection of the built-in self-heating battery electrode under all working conditions from multiple dimensions, avoiding safety hazards such as heating short circuit, overheating, voltage leakage and electrolyte corrosion.

2. The security protection system according to claim 1, characterized in that, Electrical isolation protection modules are used to physically isolate the energy storage circuit and heating circuit of the battery cell.

3. The security protection system according to claim 1, characterized in that, The structural sealing protection module uses a multi-layer thermo-press sealing structure to isolate the internal electrothermal conversion layer from electrolyte corrosion.

4. The security protection system according to claim 1, characterized in that, The hardware circuit fuse protection module integrates overcurrent protection, over-temperature power-off protection, and short-circuit self-locking protection devices.

5. The security protection system according to claim 1, characterized in that, The software strategy temperature control protection module is used to set the maximum temperature rise rate limit and the extreme temperature cut-off threshold of the battery cell.

6. The security protection system according to claim 1, characterized in that, The vehicle-wide safety protection module includes real-time monitoring of leakage in the heating circuit and rapid power-off disconnection.

7. The security protection system according to claim 1, characterized in that, The vehicle-wide safety protection module includes functions for independent identification of single-cell heating faults and isolation and control of individual faults.

8. The security protection system according to claim 1, characterized in that, During the low-temperature heating operation, the vehicle's integrated safety protection module includes synchronous monitoring of the battery cell expansion and deformation status.

9. The security protection system according to claim 1, characterized in that, The vehicle-wide safety protection module is linked to the battery pack fire alarm device to provide early warning of signs of thermal runaway. When the heating circuit malfunctions, the vehicle-wide safety protection module automatically switches to a pure energy storage safety operating mode.

10. The security protection system according to claim 1, characterized in that, The vehicle-wide safety protection module includes an online monitoring and early warning function for the aging status of the heating layer under long-term cyclic operating conditions.

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