PTC heating film, heating assembly and battery module

Abstract

The utility model relates to the technical field of lithium batteries, and discloses a PTC (Positive Temperature Coefficient) heating film, a heating assembly and a battery module, the PTC heating film comprises a base layer; the PTC thermistor layer is arranged on the base layer, the base layer supports the PTC thermistor layer, and the PTC thermistor layer emits heat to heat the battery; the covering layer is arranged on the side, away from the base layer, of the PTC thermistor layer, and the covering layer prevents water and impurities from entering the PTC thermistor layer; the thickness of the PTC heating film ranges from 1.5 mm to 3.5 mm. The heating assembly comprises the PTC heating film according to any one of claims 1-5, and the PTC heating film is electrically connected with a temperature control module used for controlling the temperature of the PTC heating film. The battery module disclosed by the utility model comprises the battery and the heating assembly, the PTC heating film is coated on the battery, and the battery module disclosed by the utility model has the technical effects of uniform heating and self temperature control in the heating process, so that the risk of thermal runaway such as local overheating in the battery heating process is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of lithium battery technology, specifically relating to a PTC heating film, a heating component, and a battery module. Background Technology

[0002] A lithium-ion battery is a battery that uses lithium metal or lithium alloy as the negative electrode material and a non-aqueous electrolyte solution. It mainly consists of a positive electrode, a negative electrode, a separator, an electrolyte, and a casing. Lithium-ion batteries achieve charging and discharging through the continuous insertion and extraction of lithium ions, which simultaneously combine with electrons. Currently, lithium-ion batteries are connected in series or parallel to form battery modules. These modules serve as energy storage devices in new energy vehicles, energy storage systems, and other fields. However, the performance of lithium-ion batteries in low-temperature environments has become a key factor restricting their further development.

[0003] At low temperatures, the viscosity of the electrolyte inside a lithium battery increases significantly, reducing the diffusion rate of lithium ions within the electrolyte. This leads to increased internal resistance, decreased charge / discharge rates, and a noticeable capacity decay. To improve the performance of lithium batteries under low-temperature conditions, resistance wire heating is typically employed.

[0004] However, resistance wire heating has problems such as high energy consumption and poor heating uniformity. Uneven heating of the resistance wire can easily cause local overheating of the lithium battery, which in turn affects the consistency and service life of the lithium battery. Utility Model Content

[0005] To address the shortcomings of the prior art, this invention provides a PTC heating film, a heating component, and a battery module. In low-temperature environments, the PTC heating film uniformly heats the battery and achieves self-temperature control during the heating process, effectively reducing the risk of thermal runaway caused by localized overheating of the battery and ensuring the safety of battery use.

[0006] The technical effects to be achieved by this utility model are realized through the following technical aspects:

[0007] In a first aspect, this utility model provides a PTC heating film, comprising a base layer; a PTC thermistor layer disposed on the base layer, the base layer supporting the PTC thermistor layer, the PTC thermistor layer generating heat to heat a battery; and a cover layer disposed on the side of the PTC thermistor layer away from the base layer, the cover layer preventing moisture and impurities from entering the PTC thermistor layer; the thickness of the PTC heating film is 1.5mm to 3.5mm.

[0008] In some implementations, the PTC thermistor layer includes conductive particles and an insulating layer, with the conductive particles uniformly distributed within the insulating layer, and the thickness of the PTC thermistor layer being 0.2 mm to 0.5 mm.

[0009] In some implementations, the base layer is a polyethylene terephthalate layer.

[0010] In some implementations, the covering layer is a polytetrafluoroethylene layer or a silicone layer.

[0011] In some implementations, the thickness of the covering layer is 0.5 mm to 2 mm.

[0012] Secondly, this utility model provides a heating component, including the aforementioned PTC heating film, wherein the PTC heating film is electrically connected to a temperature control module for controlling the temperature of the PTC heating film.

[0013] In some implementations, the PTC heating film includes a wire outlet area with a thickness of 3mm to 5mm. The PTC heating film is electrically connected to a wire at the wire outlet area and is electrically connected to the temperature control module via the wire.

[0014] In some implementations, the wire is electrically connected to a normally closed temperature switch, which is located on the battery.

[0015] In some implementations, the temperature control module includes a temperature sensor for detecting the battery temperature.

[0016] Thirdly, this utility model provides a battery module, including a battery and the above-mentioned heating component, wherein the PTC heating film covers the battery.

[0017] In summary, this utility model has at least the following advantages:

[0018] 1. The PTC heating film provided by this utility model includes a PTC thermistor layer that heats the battery. The PTC thermistor layer has a positive temperature coefficient; when its temperature rises to a specific value, its resistance increases sharply, and the heating power of the PTC thermistor layer automatically decreases, achieving precise temperature control. Compared with traditional resistance wire heating, the PTC thermistor layer can heat uniformly, effectively reducing the risk of thermal runaway due to localized overheating and mitigating battery damage caused by overheating. Simultaneously, the base layer supports the PTC thermistor layer and the cover layer. The cover layer effectively prevents moisture and impurities from entering the PTC thermistor layer. The PTC heating film heats the battery uniformly, reduces energy consumption, and improves battery safety and overall performance consistency.

[0019] 2. The heating component provided by this utility model has a temperature control module that can accurately control the battery heating temperature of the PTC heating film and realize safety monitoring of the battery heating process, thereby ensuring the safe operation of the battery. At the same time, the heat emitted by the PTC heating film can be efficiently transferred to the battery, which helps to reduce power consumption and thus reduce the operating cost of the battery.

[0020] 3. The battery module provided by this utility model has a PTC heating film covering the battery, which can maintain a suitable and stable temperature range, thereby improving the battery's performance under low temperature conditions. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a PTC heating film according to a specific embodiment of the present invention.

[0022] Figure 2 This is a top view of a heating component according to a specific embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of a battery module according to a specific embodiment of the present utility model.

[0024] Figure 4 This is a partial structural diagram of a battery module according to a specific embodiment of the present utility model.

[0025] Marked in the image:

[0026] 1. PTC heating film; 11. Base layer; 12. PTC thermistor layer; 13. Covering layer; 14. Outlet area; 2. Wire; 21. Normally closed temperature switch; 3. Battery. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of this utility model.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] Please see the appendix Figure 1The PTC heating film 1 of this utility model heats the battery 3, which can improve the performance of the battery 3 in low-temperature environments. Moreover, the PTC heating film 1 heats the battery evenly, which can effectively reduce the risk of local overheating and thermal runaway due to overheating and dry burning during the heating process, thus improving the safety of the battery 3.

[0031] The PTC heating film 1 of this utility model includes a base layer 11, which can play a role in providing stable support. In a preferred embodiment, the base layer 11 is a polyethylene terephthalate layer. The base layer 11 has good flexibility and insulation, which can provide a stable support structure while ensuring excellent electrical insulation performance and effectively reducing the possibility of short circuit. However, the above is not the only limitation on the base layer 11. In some embodiments, it can also be a polyethylene layer or a polyamide layer, etc.

[0032] A PTC thermistor layer 12 is provided on one side of the base layer 11. Specifically, the PTC thermistor layer 12 can be attached to the surface of the base layer 11. The base layer 11 supports the PTC thermistor layer 12, and the PTC thermistor layer 12 heats up to heat the battery 3.

[0033] In a preferred embodiment, the PTC thermistor layer 12 includes conductive particles and an insulating layer. The conductive particles are uniformly distributed within the insulating layer, ensuring uniform heating of the PTC thermistor layer 12. This helps reduce the possibility of uneven local heating during the heating process, which could lead to excessively high dry-burning temperatures. The PTC thermistor layer 12 has a positive temperature coefficient. During the heating process of the battery 3, when the temperature of the PTC thermistor layer 12 rises to a specific value, namely the Curie temperature, the resistance increases sharply, thereby automatically reducing the heating power and achieving precise constant temperature control.

[0034] Specifically, the conductive particles are preferably, but not limited to, carbon nanotubes and silver nanowires, and the insulating layer is preferably, but not limited to, a polyimide layer. The insulating layer can ensure the insulation of the PTC thermistor layer 12 and its stability under high-temperature conditions. Furthermore, the thickness of the PTC thermistor layer 12 is 0.2mm to 0.5mm, specifically, the thickness of the PTC thermistor layer 12 can be 0.2mm, 0.35mm, 0.4mm, or 0.5mm, etc. The PTC thermistor layer 12 has good flexibility and can fully adhere to the battery 3 to encapsulate the battery 3.

[0035] A cover layer 13 is provided on the side of the PTC thermistor layer 12 away from the base layer 11. The cover layer 13 can effectively prevent moisture and impurities from entering the interior of the PTC thermistor layer 12, thereby extending the service life of the PTC thermistor layer 12. In the PTC heating film 1, the cover layer 13, the PTC thermistor layer 12 and the base layer 11 are stacked in sequence. The cover layer 13 and the base layer 11 provide double protection for the PTC thermistor layer 12, so as to effectively prevent the PTC thermistor layer 12 from being damaged by external environmental factors such as moisture and corrosion during use, thereby improving the overall stability and reliability of the PTC heating film 1.

[0036] In a preferred embodiment, the cover layer 13 is a polytetrafluoroethylene (PTFE) layer or a silicone layer. The cover layer 13 possesses good high-temperature resistance and corrosion resistance. The cover layer 13 separates the PTC thermistor layer 12 from the external environment, which helps extend the service life of the PTC thermistor layer 12. It is understood that this is not a specific limitation on the selection of the cover layer 13, and those skilled in the art can make substitutions based on this. Furthermore, the thickness of the cover layer 13 is 0.5mm to 2mm, such as 0.5mm, 1mm, 1.5mm, or 2mm, etc., and the cover layer 13 effectively transfers heat.

[0037] The thickness of the PTC heating film 1 is 1.5mm to 3.5mm. Specifically, the PTC heating film 1 can be 1.5mm, 2.5mm or 3.5mm, etc.

[0038] In low-temperature environments, the PTC thermistor layer 12 generates heat, which passes through the base layer 11 or the covering layer 13 to heat the battery 3. The PTC thermistor layer 12 automatically adjusts its heating power based on the actual temperature of the battery 3, utilizing its positive temperature coefficient characteristic. The PTC heating film 1 achieves precise constant-temperature heating without the need for a complex temperature feedback control system. Compared to traditional resistance wire heating, the uniform heating characteristics and self-temperature control of the PTC thermistor layer 12 effectively reduce the risk of thermal runaway in the battery 3 due to uneven local heating or excessively high dry-burning temperatures, ensuring the safety and performance consistency of the battery 3 and mitigating damage caused by overheating.

[0039] Example 2:

[0040] This embodiment, based on the above embodiments, provides a heating component. Please refer to [link / reference]. Figure 2 .

[0041] A heating component includes the aforementioned PTC heating film 1. Specifically, the PTC heating film 1 can be a square film. The PTC heating film 1 is electrically connected to a temperature control module for controlling the temperature of the PTC heating film 1. The temperature control module can perform safety monitoring and precise control of the heating working state of the battery 3 during the heating process, so that the PTC heating film 1 can operate safely under any circumstances.

[0042] In a preferred embodiment, the PTC heating film 1 includes a wire outlet area 14, the thickness of which is 3mm to 5mm. Specifically, the thickness of the wire outlet area 14 can be 3mm, 4mm, or 5mm. A wire 2 is electrically connected to the PTC heating film 1 at the wire outlet area 14, and is electrically connected to the temperature control module via the wire 2. Specifically, the PTC heating film 1 can be soldered to the wire 2 at the wire outlet area 14 to achieve a stable connection. A plug is provided on the wire 2.

[0043] In a preferred embodiment, the wire 2 is electrically connected to a normally closed temperature switch 21. Specifically, the wire 2 includes a positive electrode harness and a negative electrode harness. The normally closed temperature switch 21 is connected in series with the positive electrode harness and is located on the battery 3. As shown in some specific embodiments, the set temperature of the normally closed temperature switch 21 can be 70°C. When the normally closed temperature switch 21 detects that the battery 3 has heated to a temperature higher than the set temperature, the normally closed temperature switch 21 automatically disconnects, and the PTC heating film 1 stops heating. The normally closed temperature switch 21, together with the temperature control module, can provide a double safety function.

[0044] In a preferred embodiment, the temperature control module includes a temperature sensor for detecting the temperature of the battery 3. Specifically, the temperature sensor can be installed at key locations in the battery module, such as the surface of the battery, between the positive and negative electrodes, or at the connection points between the various modules of the battery 3, to detect temperature changes inside the battery 3 in real time. Furthermore, the temperature sensor is electrically connected to an intelligent control unit, which is connected to the PTC heating film 1 via the plug of the wire 2. The intelligent control unit precisely controls the heating operation of the PTC heating film 1. Specifically, the intelligent control unit can be a BMS with heating functionality.

[0045] When the PTC heating film 1 heats the battery 3, the temperature sensor transmits the collected temperature signal to the intelligent control unit. The intelligent control unit automatically adjusts the working state of the PTC heating film 1 according to the preset temperature range. When the temperature of the battery 3 is lower than the set low temperature threshold, the intelligent control unit activates the PTC thermistor layer 12 in the PTC heating film 1 to heat the battery 3. When the surface of the PTC heating film 1 reaches the set temperature, such as 60°C, the temperature of the PTC thermistor layer 12 stops rising, and constant temperature heating is achieved. When the temperature sensor senses that the internal temperature of the battery 3 has reached the suitable temperature set by the intelligent control unit, the intelligent control unit reduces the heating power of the PTC thermistor layer 12 or stops heating, thereby achieving precise temperature control of the battery 3 through the PTC heating film 1. The method by which the intelligent control unit controls the heating power to adjust the heating state of the PTC heating film 1 is known to those skilled in the art and is achievable, and will not be described in detail in this embodiment.

[0046] The temperature control module and the self-temperature control of the PTC heating film 1 help to automatically reduce power consumption, reduce unnecessary energy waste, thereby improving energy utilization efficiency and reducing the operating cost of battery 3.

[0047] Example 3:

[0048] This embodiment, based on the above embodiments, provides a battery module. Please refer to [link / reference]. Figure 3 and Figure 4 .

[0049] A battery module includes a battery 3 and the aforementioned heating assembly. A PTC heating film 1 covers the surface of the battery 3. In some specific embodiments shown, the battery 3 may be a cylindrical battery 3. The PTC heating film 1 wraps around the surface of the battery 3, and a base layer 11 or a cover layer 13 is in contact with the battery 3. The PTC heating film 1 is U-shaped and interspersed among multiple batteries 3, wrapping the battery 3 to be heated. The PTC heating film 1 can be adhered to the battery 3 with adhesive to ensure good contact between the PTC heating film 1 and the battery 3. Simultaneously, a normally closed temperature switch 21 is attached to the surface of the battery 3.

[0050] In low-temperature environments, the PTC heating film 1 can be activated quickly and raise the temperature of the battery 3 to a suitable range. During the charging and discharging process of the battery module, the temperature of the battery 3 remains stable, which is beneficial to improving the charging and discharging efficiency and capacity retention rate of the battery 3 under low-temperature conditions.

[0051] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0052] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0053] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0054] In this invention, unless otherwise expressly specified and limited, "above or below" the first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0055] Although the description of this utility model has been given in conjunction with the specific embodiments described above, it is obvious to those skilled in the art that many substitutions, modifications, and variations can be made based on the above description. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A PTC heating film, characterized by, Comprising a base layer (11); a PTC thermistor layer (12) disposed on the base layer (11), the base layer (11) supporting the PTC thermistor layer (12), the PTC thermistor layer (12) generating heat to heat the battery (3); and a cover layer (13) disposed on a side of the PTC thermistor layer (12) away from the base layer (11), the cover layer (13) blocking moisture and impurities from entering the PTC thermistor layer (12); the PTC heating film (1) has a thickness of 1.5mm-3.5mm.

2. The PTC heating film according to claim 1, characterized in that, The PTC thermistor layer (12) comprises conductive particles and an insulating layer, the conductive particles being uniformly distributed in the insulating layer, and the PTC thermistor layer (12) has a thickness of 0.2mm-0.5mm.

3. The PTC heating film according to claim 1, characterized in that, The base layer (11) is a polyethylene terephthalate layer.

4. The PTC heating film according to claim 1, characterized in that, The cover layer (13) is a polytetrafluoroethylene layer or a silica gel layer.

5. The PTC heating film according to claim 4, characterized in that, The cover layer (13) has a thickness of 0.5mm-2mm.

6. A heating assembly characterized by, The PTC heating film (1) of any one of claims 1-5 is electrically connected with a temperature control module for controlling the temperature of the PTC heating film (1).

7. The heating assembly of claim 6, wherein, The PTC heating film (1) comprises a wire outlet area (14) having a thickness of 3mm-5mm, and the PTC heating film (1) is electrically connected with a wire (2) at the wire outlet area (14) and is electrically connected with the temperature control module through the wire (2).

8. The heating assembly of claim 7, wherein, The wire (2) is electrically connected with a normally closed temperature switch (21), and the normally closed temperature switch (21) is disposed on the battery (3).

9. The heating assembly of claim 6, wherein, The temperature control module comprises a temperature sensor for detecting the temperature of the battery (3).

10. A battery module, characterized by The battery (3) and the heating assembly of any one of claims 6-9, wherein the PTC heating film (1) is wrapped around the battery (3).

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