A heat dissipation module for lithium battery

Abstract

The utility model discloses a kind of heat dissipation modules for lithium battery, including battery core and the multiple layer heat dissipation flexible module adhered to its surface, the multiple layer heat dissipation flexible module uses double-layer PAM / PEG / Si3N4 composite film as core heat dissipation layer, and instantaneous heat generated by phase-change material absorption battery core charge and discharge;The film surface covers honeycomb aluminum foil and is laser welded with openwork aluminum-magnesium alloy shell, forms " phase-change layer+heat conduction layer+radiation layer " composite structure.The utility model technical scheme further in composite film surface chemical vapor deposition vertically arranged carbon nanotube array, constructs directional heat conduction network.The utility model also integrates intelligent temperature control system, realizes closed-loop heat dissipation control by film temperature sensor, micro fan and PCB board, finally realizes the technical effect of battery's efficient heat buffering, rapid heat conduction, active heat dissipation.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery heat dissipation technology, and in particular to a heat dissipation module for lithium batteries. Background Technology

[0002] With the rapid development of new energy vehicles and energy storage technologies, lithium batteries are widely used due to their high energy density. However, the heat generated during charging and discharging can easily lead to uneven cell temperature, shortened cycle life, and even thermal runaway. Traditional heat dissipation solutions, such as metal heat sinks or liquid cooling systems, suffer from problems such as large weight, complex structure, and slow response. For example, metal heat sinks rely on passive conduction, making it difficult to cope with instantaneous high heat loads; liquid cooling systems require additional pump and valve components, increasing energy consumption and the risk of failure.

[0003] In existing technologies, while phase change materials can absorb heat, they pose a risk of leakage and have insufficient thermal conductivity; while single thermally conductive structures (such as graphene coatings) cannot simultaneously meet the requirements of thermal buffering and rapid heat dissipation. Furthermore, existing temperature control systems mostly employ centralized sensor layouts, making it difficult to accurately monitor localized hot spots within the battery cell. Therefore, there is an urgent need for a heat dissipation module that integrates efficient thermal buffering, rapid heat conduction, and intelligent temperature control to address the technical bottlenecks in lithium battery thermal management. Utility Model Content

[0004] This application provides a heat dissipation module for lithium batteries. Through a three-level structural innovation of "phase change material encapsulation + honeycomb aluminum foil thermal conduction + carbon nanotube directional heat transfer", it solves the problem of thermal runaway in lithium batteries, thereby achieving the technical effects of efficient thermal buffering, rapid thermal conduction and active heat dissipation of the battery.

[0005] This application provides a heat dissipation module for lithium batteries, characterized in that it includes: Battery cells, A multi-layer flexible heat dissipation module is attached to the surface of the battery cell. The multi-layer flexible heat dissipation module uses a double-layer PAM / PEG / Si3N4 composite film as the core heat dissipation layer. The PAM / PEG / Si3N4 composite film is cut into strips that match the size of the battery cell and the thickness of the PAM / PEG / Si3N4 composite film is 0.3mm. Honeycomb aluminum foil covering the multi-layer heat dissipation flexible module; The heat dissipation module housing is welded to the honeycomb aluminum foil, and the housing is made of a hollow aluminum-magnesium alloy frame with a hollow area accounting for ≥45%.

[0006] Preferably, a vertically aligned array of carbon nanotubes is embedded in the surface of the PAM / PEG / Si3N4 composite film using chemical vapor deposition.

[0007] Preferably, the carbon nanotube array has a height of 50 μm and a spacing of 10 μm.

[0008] Preferably, a miniature temperature control PCB board is installed on the top of the module housing, and thin-film temperature sensors are installed on the corresponding PAM / PEG / Si3N4 composite film surfaces at the tabs, central area, and four key corners of the battery cell. The thin-film temperature sensors are connected to the miniature temperature control PCB board via flexible FPC cables. A miniature fan is installed at the air inlet on the side of the module housing and connected to the miniature temperature control PCB board via a 2-pin socket.

[0009] Preferably, a flexible silicone buffer layer is provided between the PAM / PEG / Si3N4 composite film and the battery cell.

[0010] One technical solution provided in this application embodiment has at least the following technical effects or advantages: 1. This utility model solves the problem of thermal runaway in lithium batteries through a three-level structural innovation of "phase change material encapsulation + honeycomb aluminum foil thermal conduction + carbon nanotube directional heat transfer", thereby achieving the technical effects of efficient thermal buffering, rapid thermal conduction and active heat dissipation of the battery.

[0011] 2. This utility model constructs a multi-level heat conduction network through the synergistic effect of honeycomb aluminum foil and carbon nanotube array, which reduces thermal resistance by 35% and controls the temperature difference between battery cells within ±2℃, significantly improving the uniformity of heat distribution.

[0012] 3. This utility model combines an intelligent temperature control system to adjust the speed of the micro fan in real time, realizing dynamic heat dissipation through "phase change heat absorption and forced convection". Under 2C charge and discharge conditions, the overall temperature rise of the battery module is ≤15℃, and the range stability is improved by 40%. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the heat dissipation module structure in Embodiment 1 of this application; Figure 2 This is a schematic diagram of the battery module housing in Embodiment 1 of this application; Figure 3 for Figure 1 A magnified partial view of part A in the middle; Figure 4 The absorption rate of infrared light for the PAM / PEG / Si3N4 composite film.

[0014] 1-Battery cell; 2-Multi-layer composite heat dissipation module; 3-Honeycomb aluminum foil; 4-Module shell; 5-Flexible silicone buffer layer. Detailed Implementation

[0015] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods. Example 1

[0016] This application provides a heat dissipation module for lithium batteries, including a battery cell 1 and a multi-layer composite heat dissipation module 2 bonded to the surface of the battery cell 1. The multi-layer composite heat dissipation module 2 uses a double-layer PAM / PEG / Si3N4 composite film as the core heat dissipation layer. A three-dimensional network of PAM hydrogel is used to seal the phase change material PEG, further improving the leakage prevention capability of the double-layer PAM / PEG / Si3N4 composite film. The high thermal conductivity of Si3N4 accelerates the heat transfer performance of the composite film. The 0.3mm thick double-layer PAM / PEG / Si3N4 composite film is cut into strips matching the size of the battery cell 1 and then bonded to the surface of the battery cell 1. The phase change material absorbs the instantaneous heat generated during the charging and discharging of the battery cell 1.

[0017] Then, a 0.1 mm thick honeycomb aluminum foil 3 is coated on the double-layer PAM / PEG / Si3N4 composite film to form a composite structure of "phase change layer + thermally conductive layer + radiation layer", which accelerates the diffusion of heat to the external environment. The honeycomb aluminum foil 3 is connected to the battery module shell 4 by laser welding to ensure maximum thermal contact area.

[0018] Among them, the battery module shell 4 has a wave-shaped hollow structure with a hollow area accounting for ≥45%, which maximizes both mechanical strength and heat dissipation surface area, while reducing weight by 30% compared to traditional metal shells.

[0019] In this embodiment, a flexible silicone buffer layer 5 with a thickness of 0.5 mm can be provided between the double-layer PAM / PEG / Si3N4 composite film and the battery cell 1. The buffer layer has a built-in micro-airbag structure, which can absorb the volume expansion stress during battery charging and discharging, and at the same time avoid the film from cracking due to mechanical deformation.

[0020] In this embodiment, carbon nanotube arrays with a height of 50 μm and a spacing of 10 μm can also be grown by chemical vapor deposition (CVD) on the surface of a bilayer PAM / PEG / Si3N4 composite film to form a vertical thermally conductive network, thereby constructing a fast thermal conduction path from the inside of the battery cell to the outer shell of the module and reducing thermal resistance.

[0021] This application embodiment can also install thin-film temperature sensors on the corresponding PAM / PEG / Si3N4 composite film surfaces at the tabs, central area, and four key corners of the battery cell. A miniature fan (15mm×15mm×5mm in size, power ≤0.5W) is installed at the air inlet on the side of the module housing. A miniature temperature control PCB board is installed on the top of the module housing. The thin-film temperature sensors are connected to the miniature temperature control PCB board via a 0.1mm thick flexible FPC cable. The miniature fan is connected to the miniature temperature control PCB board via a 2-pin connector. The PCB board integrates a low-power MCU and an ESP32-C3 Bluetooth module (such as ESP32) to achieve wireless transmission of temperature data, which is transmitted to a mobile APP via the BLE 5.0 protocol, supporting real-time monitoring by the mobile APP. When the temperature at the monitoring point is >45℃, the MCU outputs a PWM signal to drive the fan to start, forming a "phase change heat absorption - forced convection" collaborative heat dissipation mechanism to ensure that the cell temperature gradient is ≤2℃. This application embodiment achieves accurate temperature measurement by the thin-film sensor → heat absorption by the phase change material → forced heat dissipation by the fan, forming a closed-loop control.

[0022] Performance verification of the heat dissipation module: Test conditions: The lithium battery pack was charged and discharged at a rate of 2C for 100 cycles, and the ambient temperature was 30℃.

[0023] Results: (1) The maximum temperature of the battery pack using this heat dissipation structure is ≤48℃, which is 22.6% lower than the traditional natural heat dissipation scheme (maximum 62℃).

[0024] (2) The carbon nanotube thermal conduction channels control the temperature difference between cells within ±2℃, significantly improving battery consistency.

[0025] (3) After 1000 charge-discharge cycles, the flexible buffer layer showed no leakage and the cell expansion rate was <1%.

[0026] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0027] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A heat dissipation module for lithium batteries, characterized in that, include: Battery cells, A multi-layer flexible heat dissipation module is attached to the surface of the battery cell. The multi-layer flexible heat dissipation module uses a double-layer PAM / PEG / Si3N4 composite film as the core heat dissipation layer. The PAM / PEG / Si3N4 composite film is cut into strips that match the size of the battery cell and the thickness of the PAM / PEG / Si3N4 composite film is 0.3mm. Honeycomb aluminum foil covering the multi-layer heat dissipation flexible module; The heat dissipation module housing is welded to the honeycomb aluminum foil, and the housing is made of a hollow aluminum-magnesium alloy frame with a hollow area accounting for ≥45%.

2. The heat dissipation module for lithium batteries as described in claim 1, characterized in that, A vertically aligned array of carbon nanotubes was embedded in the surface of the PAM / PEG / Si3N4 composite film using chemical vapor deposition.

3. A heat dissipation module for lithium batteries as described in claim 2, characterized in that, The carbon nanotube array has a height of 50 μm and a spacing of 10 μm.

4. A heat dissipation module for lithium batteries as described in claim 1, characterized in that, A miniature temperature control PCB board is installed on the top of the module housing. Thin film temperature sensors are installed on the surface of the PAM / PEG / Si3N4 composite film at the tabs, central area, and four key corners of the battery cell. The thin film temperature sensors are connected to the miniature temperature control PCB board via flexible FPC cables. A miniature fan is installed at the air inlet on the side of the module housing and connected to the miniature temperature control PCB board via a 2-pin socket.

5. A heat dissipation module for lithium batteries as described in claim 1, characterized in that, A flexible silicone buffer layer is provided between the PAM / PEG / Si3N4 composite film and the battery cell.

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