Multifunctional composite breathing film, heat insulation assembly, battery module and battery pack

Abstract

The utility model discloses a multifunctional composite breathing film, a heat insulation assembly, a battery module and a battery pack, the multifunctional composite breathing film comprises a phase change layer and a heat insulation packaging film wrapping the phase change layer, and a temperature sensing viscous coating is arranged on the outer surface of the heat insulation packaging film; the phase change layer is in a liquid state within the working temperature range of the battery cell, and the viscosity of the temperature-sensitive viscous coating is gradually weakened along with the rise of the temperature. According to the multifunctional composite breathing film provided by the utility model, the outer temperature sensing viscous coating is bonded with the battery cell, the inner phase change layer can completely meet the ballooning caused by a large surface when the battery cell is charged and discharged, and the breathing film can be automatically adjusted according to the ballooning degrees of different areas on the large surface of the battery cell; therefore, the large surface of the whole battery cell is under the same pre-tightening pressure, the attenuation of the battery cell is improved, and the cycle life of a battery pack is greatly prolonged. Meanwhile, the heat insulation packaging film has excellent heat insulation blocking performance, and heat spreading of the thermal runaway battery cell can be effectively isolated.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, and in particular to a multifunctional composite breathing membrane and heat insulation component, battery module, and battery pack. Background Technology

[0002] Currently, the power battery packs used in new energy vehicles primarily utilize lithium-ion cells. These cells need to operate within a certain preload range to ensure optimal charge and discharge characteristics. Therefore, a certain preload is required for the cells to charge and discharge comfortably. When cells are integrated into modules, rigid PC sheets, aerogel, and elastic foam are added between the cells to provide a specific preload range. These materials also act as insulation in case of thermal runaway, preventing heat propagation between the cells.

[0003] When assembling modules, rigid PC sheets or aerogel sheets are used for heat insulation between the cells. However, rigid PC sheets and aerogel sheets are incompressible, which is detrimental to the module (or battery pack) during the later stages of charging and discharging, significantly reducing the overall lifespan of the pack. When using elastic foam materials for heat insulation between the cells, the foam's compressibility and elasticity can absorb the expansion caused by the cells during charging and discharging. However, because the cells are large and the expansion is uneven, uneven bulging can occur in certain areas. Elastic foam materials can only passively accept the pressure from the cell expansion and do not actively adjust to ensure even stress distribution across the cell surface. Over time, this also reduces the battery pack's lifespan. Furthermore, since the heat insulation materials between the cells are bonded to the cell surfaces with strong adhesive, they are difficult to remove for later reuse and are extremely inconvenient. Utility Model Content

[0004] Based on this, and in view of the technical problems existing in the current use of rigid PC sheets, aerogel sheets or elastic foam materials as heat insulation materials between cells in battery packs, this utility model needs to provide a multifunctional composite breathing membrane and heat insulation component, battery module, and battery pack.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a multifunctional composite breathing membrane, which includes a phase change layer and a heat insulation encapsulation film wrapped around the phase change layer. The outer surface of the heat insulation encapsulation film is provided with a temperature-sensitive adhesive coating. The phase change layer is in a liquid state within the operating temperature range of the battery cell, and the adhesiveness of the temperature-sensitive adhesive coating gradually weakens as the temperature increases.

[0007] As a further improvement to the above scheme, several miniature patch temperature sensors are installed inside the phase change layer.

[0008] As a further improvement to the above scheme, several miniature patch pressure sensors are installed inside the phase change layer.

[0009] As a further improvement to the above solution, the outer surface of the temperature-sensitive adhesive coating is covered with a peelable release paper.

[0010] As a further improvement to the above scheme, the temperature-sensitive adhesive coating is made of poly(N-isopropylacrylamide) or acrylonitrile-methacrylate copolymer.

[0011] As a further improvement to the above scheme, the phase change layer is made of paraffin, fatty acid, or brine compound.

[0012] As a further improvement to the above solution, the heat insulation encapsulation film is an aluminum foil film, a PET reflective film, or a phase change heat insulation film.

[0013] This utility model also provides a heat insulation component, which includes the multifunctional composite breathable membrane as described above.

[0014] This utility model also provides a battery module, which includes multiple battery cells, and a heat insulation pad is provided between any two adjacent battery cells. The heat insulation pad adopts the multifunctional composite breathable membrane as described above.

[0015] This utility model also provides a battery pack, which includes the battery module as described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The multifunctional composite breathing membrane provided by this invention utilizes an outer temperature-sensitive adhesive coating to bond with the battery cell, while the inner phase change layer fully accommodates the bulging caused by the large surface area during charging and discharging of the battery cell. The breathing membrane automatically adjusts according to the degree of bulging in different areas of the large surface area of ​​the battery cell, thereby ensuring that the entire large surface area of ​​the battery cell is under the same pre-tightening pressure. This improves cell degradation and significantly extends the cycle life of the battery pack. Simultaneously, the heat-insulating encapsulation film itself possesses excellent heat-insulating and blocking properties, effectively preventing the thermal runaway of the battery cell from spreading.

[0018] The multifunctional composite breathing membrane provided by this utility model can reduce the adhesion strength between the breathing membrane and the surface of the battery cell by rapid heating, which facilitates the rapid disassembly of the battery cell and provides convenience for the cascade utilization of the battery pack for after-sales service, repair and other purposes.

[0019] The multifunctional composite breathing membrane provided by this utility model contains a miniature patch pressure sensor and a miniature patch temperature sensor, which monitor the working status of all battery cells in real time. By connecting the miniature patch pressure sensor and the miniature patch temperature sensor to the BMS to communicate with the whole vehicle, the car owner can view the status of all battery cells in real time. In the event of a sudden abnormality in the battery pack (such as thermal runaway), the car owner can quickly see and react. This function can detect abnormal sudden situations much earlier than the mainstream battery packs on the market, providing the car owner with more time to escape or react. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a multifunctional composite breathing membrane proposed in an embodiment of the present invention;

[0021] Figure 2 An exploded view of a multifunctional composite respiratory membrane proposed in an embodiment of this utility model;

[0022] Figure 3 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present invention;

[0023] Figure 4 An exploded view of a battery pack according to an embodiment of this utility model;

[0024] Figure 5 This is an assembly diagram of a battery cell and a multifunctional composite breathing membrane in a battery pack according to an embodiment of the present invention;

[0025] Figure 6 This is an assembly diagram of an integrated cover plate and battery cell in a battery pack according to an embodiment of the present utility model;

[0026] Figure 7 This is an assembly diagram of a data acquisition harness and integrated cover plate in a battery pack according to an embodiment of the present invention.

[0027] Reference numerals: 1. Multifunctional composite breathing membrane; 11. Phase change layer; 12. Thermal insulation encapsulation film; 13. Temperature-sensitive adhesive coating; 14. Miniature patch temperature sensor; 15. Miniature patch pressure sensor; 16. Release paper; 2. Battery cell; 3. Integrated cover plate; 4. Data acquisition harness; 5. Low-voltage communication port; 6. Low-voltage management system; 7. High-voltage output port; 8. High-voltage control box; 9. Lower housing. Detailed Implementation

[0028] To facilitate understanding of this invention, a more comprehensive description of the invention will be provided below with reference to specific embodiments. However, this invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure of this invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0030] Reference Figure 1 , Figure 2 This embodiment proposes a multifunctional composite breathing membrane, which includes a phase change layer 11 and a heat insulation encapsulation film 12 wrapped around the phase change layer 11. A temperature-sensitive adhesive coating 13 is provided on the outer surface of the heat insulation encapsulation film 12.

[0031] In this embodiment, the phase change layer 11 is a liquid-molten-semi-solid phase change material, and the phase change is reversible. The phase change layer 11 is in a liquid state within the operating temperature range of the battery cell (20-40℃). In this embodiment, the phase change layer 11 is prepared using commercially available paraffin wax.

[0032] The heat-insulating encapsulation film 12 has excellent heat insulation and blocking properties, which can effectively prevent the thermal runaway of the battery cell 2 from spreading. In this embodiment, the heat-insulating encapsulation film 12 is a commercially available PET reflective film.

[0033] The temperature-sensitive adhesive coating 13 is adhesive and is used to bond the multifunctional composite breathable membrane 1 to the battery cell 2. Furthermore, the temperature-sensitive adhesive coating 13 undergoes a reversible phase transition with temperature changes. In this embodiment, the temperature-sensitive adhesive coating 13 is made of poly(N-isopropylacrylamide) material, and its adhesiveness gradually weakens as the temperature increases. This allows the adhesive strength between the temperature-sensitive adhesive coating 13 and the battery cell 2 to instantly fail under electromagnetic induction heating, facilitating the disassembly of the battery cell 2. This significantly simplifies the disassembly process and improves convenience when the module needs to be disassembled for reuse, such as when it reaches the end of its service life or is returned for repair.

[0034] To facilitate transportation, before use, the multifunctional composite breathable membrane of this embodiment is covered with a glass-like release paper 16 on the outer surface of the temperature-sensitive adhesive coating 13. During the assembly of the mold, the release paper 16 is directly peeled off, and the multifunctional composite breathable membrane 1 is placed between the battery cells 2 to bond with the battery cells 2.

[0035] To monitor the working status of all battery cells 2, the multifunctional composite breathing membrane in this embodiment is equipped with several micro-pattern temperature sensors 14 and several micro-pattern pressure sensors 15 in the phase change layer 11. When the module is assembled, the micro-pattern temperature sensors 14 and micro-pattern pressure sensors 15 are connected to the BMS to communicate with the vehicle, so that the car owner can view the status of all battery cells 2 in real time. In the event of a sudden abnormality in the battery pack (such as thermal runaway), the car owner can quickly see and react, giving the car owner more time to escape.

[0036] The multifunctional composite breathing membrane 1 of this embodiment is designed according to different types of battery cells 2 and the size of the battery cell 2 area. It can be any shape such as rectangle, square, ellipse, ring, etc., and the thickness can be uniform wall thickness or stepped variable thickness. The arrangement and number of miniature patch temperature sensor 14 and miniature patch pressure sensor 15 are also customized according to different battery pack design requirements. This embodiment does not impose specific restrictions.

[0037] The multifunctional composite breathing membrane 1 of this embodiment can be manufactured by the following method: the micro-patch temperature sensor 14 and the micro-patch pressure sensor 15 are immersed in molten paraffin wax and solidified to form a phase change layer 11; then the phase change layer 11 and the micro-patch temperature sensor 14 and the micro-patch pressure sensor 15 inside are wrapped by a heat-insulating encapsulation film 12 and encapsulated by hot pressing; then poly-N-isopropylacrylamide material is sprayed on the surface of the heat-insulating encapsulation film 12 to form a temperature-sensitive adhesive coating 13; finally, release paper is used to cover the surface of the temperature-sensitive adhesive coating 13.

[0038] Reference Figures 3-7 Based on the aforementioned multifunctional composite breathing membrane 1, this embodiment also provides a battery pack, which includes multiple battery cells 2, multiple multifunctional composite breathing membranes 1, a low-voltage management system 6, two integrated cover plates 3, a high-voltage control box 8, and a lower housing 9. Multiple battery cells 2 are stacked in a predetermined direction within the lower housing 9, and a multifunctional composite breathing membrane 1 is disposed between any two adjacent battery cells 2. Integrated cover plates 3 are respectively mounted on both sides of the battery cells 2. The integrated cover plates 3 are connected to a miniature patch temperature sensor 14 and a miniature patch pressure sensor 15 for data acquisition, and the integrated cover plates 3 are plugged into a data acquisition harness 4.

[0039] The battery pack is mounted on the vehicle, with its high-voltage output port and low-voltage communication port connected to the vehicle's high-voltage and control systems, respectively. When the vehicle is in motion, each cell 2 is in a discharging state. The temperature and real-time pressure distribution of each cell 2 are processed by the low-voltage management system 6 and then transmitted to the vehicle via the low-voltage communication port 5. The vehicle owner can view the real-time status of each cell 2 on the instrument panel. The same applies when the battery pack is charging.

[0040] Since the phase change layer 11 of the multifunctional composite breathing membrane 1 is in a liquid state, it can achieve uniform matching according to the expansion of all the large surfaces of the cell 2, so that the entire large surface of the cell 2 is under the same pre-tightening pressure, the cell 2 degradation is improved, and the cycle life of the battery pack is greatly improved.

[0041] When a certain cell 2 malfunctions, since the sampling point is located at cell 2, the car owner can quickly see the faulty cell 2 through the car's dashboard or with the help of a mobile phone app.

[0042] It should be noted that when a component is said to be "installed on" another component, it can be directly on the other component or it may be in a component that is centered on it. When a component is said to be "set on" another component, it can be directly set on the other component or it may also be in a component that is centered on it. When a component is said to be "fixed to" another component, it can be directly fixed to the other component or it may also be in a component that is centered on it.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A multifunctional composite respiratory membrane, characterized in that, It includes a phase change layer (11) and a heat insulation encapsulation film (12) wrapped around the phase change layer (11). A temperature-sensitive adhesive coating (13) is provided on the outer surface of the heat insulation encapsulation film (12). The phase change layer (11) is in a liquid state within the operating temperature range of the battery cell, and the adhesiveness of the temperature-sensitive adhesive coating (13) gradually weakens as the temperature increases.

2. The multifunctional composite respiratory membrane according to claim 1, characterized in that, Several miniature patch temperature sensors (14) are disposed within the phase change layer (11).

3. The multifunctional composite respiratory membrane according to claim 1, characterized in that, Several miniature patch pressure sensors (15) are installed inside the phase change layer (11).

4. The multifunctional composite respiratory membrane according to claim 1, characterized in that, The outer surface of the temperature-sensitive adhesive coating (13) is covered with a peelable release paper (16).

5. The multifunctional composite respiratory membrane according to claim 1, characterized in that, The temperature-sensitive adhesive coating (13) is made of poly(N-isopropylacrylamide) material or acrylonitrile-methacrylate copolymer.

6. The multifunctional composite respiratory membrane according to claim 1, characterized in that, The phase change layer (11) is made of paraffin, fatty acid or salt water compound.

7. The multifunctional composite respiratory membrane according to claim 1, characterized in that, The heat insulation encapsulation film (12) is an aluminum foil film, a PET reflective film, or a phase change heat insulation film.

8. A thermal insulation component, characterized in that, It includes the multifunctional composite respiratory membrane as described in any one of claims 1-7.

9. A battery module comprising a plurality of battery cells (2), wherein a heat insulation pad is disposed between any two adjacent battery cells (2), characterized in that, The heat insulation pad is a multifunctional composite breathable membrane as described in any one of claims 1-7.

10. A battery pack, characterized in that, It includes the battery module as described in claim 9.

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