Diaphragm structure, battery, battery pack, battery pack and electric equipment
By setting thermal responsive materials inside the diaphragm, the problem of thermal runaway of lithium-ion batteries at high temperatures is solved, the safety performance of the diaphragm is improved, and the risk of battery overheating is reduced.
Patent Information
- Application Number
- CN202510845868.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-23
- Publication Date
- 2025-09-30
AI Technical Summary
The separators of existing lithium-ion batteries are prone to shrinkage or melting at high temperatures, leading to thermal runaway, posing a safety hazard and potentially causing equipment failure and fire.
A thermally responsive material is set inside the diaphragm. When the temperature reaches a certain value, the thermally responsive material melts and covers the surface of the diaphragm, blocking ion transmission and releasing flame retardant to inhibit thermal runaway.
It effectively reduces the risk of battery thermal runaway, improves battery safety performance, and reduces the possibility of overheating.
Smart Images
Figure CN120728167A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of battery technology, and in particular to a diaphragm structure, a battery, a battery pack, a battery package and an electrical device. Background Art
[0002] Lithium-ion batteries are developing rapidly and becoming increasingly popular in the current industry. Their energy density has greatly increased, their cost has gradually decreased, and their scope of application has been widely expanded. However, as their usage increases, so have related accidents. Overheating of lithium-ion battery systems can cause exothermic reactions and thermal runaway, which can ultimately lead to equipment failure or even fire and explosion, threatening life safety. Therefore, improving the safety performance of lithium-ion batteries and reducing potential safety hazards have become important driving forces for the leapfrog development of the current industry. The main function of the diaphragm is to separate the cathode and anode (positive and negative) materials of the battery to prevent short circuits caused by contact between the two levels. In addition, during electrochemical reactions, it can maintain the necessary electrolyte and form a channel for ion movement. Currently, the diaphragms of lithium-ion batteries are mostly single-layer polyolefin diaphragms, which have limited thermal stability. If the temperature is too high, the diaphragm will shrink or melt, which can easily cause thermal runaway and pose a safety hazard. Summary of the Invention
[0003] The present application provides a diaphragm, a battery, a battery pack, a battery package and an electrical device to effectively suppress the occurrence of thermal runaway and reduce safety hazards.
[0004] In order to achieve the above objectives, this application adopts the following technical solutions:
[0005] In one aspect, the present application provides a diaphragm structure, comprising:
[0006] a diaphragm, wherein an accommodating space is formed inside the diaphragm;
[0007] A thermally responsive material is disposed in the accommodating space and is adapted to melt when the heated temperature reaches a predetermined value and to cover the inner surface of the diaphragm.
[0008] In a possible implementation, the diaphragm structure further includes a matrix, the matrix fills the accommodating space, and the thermal responsive material is dispersed in the matrix.
[0009] In a possible implementation, the diaphragm has at least two diaphragm base layers, and the accommodating space is formed between the at least two diaphragm base layers.
[0010] In a possible implementation, the thermally responsive material is provided with an internal space, and a flame retardant is provided in the internal space.
[0011] In a possible implementation, the thermally responsive material includes an organic material.
[0012] In a possible implementation, the material of the separator includes polyolefin.
[0013] In a possible implementation, the thermally responsive material includes a thermistor material.
[0014] In a possible implementation, the thermistor material includes a PTC material.
[0015] In a possible implementation, polydopamine is provided on the surface of the thermoresponsive material opposite to the diaphragm.
[0016] In a possible implementation, the flame retardant includes triphenyl phosphate.
[0017] In a possible implementation, the matrix includes PVDF glue.
[0018] In a possible implementation, the thickness of the diaphragm is 5 to 8 microns.
[0019] In a possible implementation, the volume of the internal space of the thermally responsive material is 0.5 to 1.5 cubic micrometers.
[0020] According to the first aspect of the present invention, the present application provides a battery comprising a positive electrode sheet, a negative electrode sheet, and a diaphragm structure disposed between the positive electrode sheet and the negative electrode sheet, wherein the diaphragm structure is the diaphragm structure described above.
[0021] According to a second aspect of the present invention, the present application provides a battery pack, comprising a box and a battery, wherein the battery is placed in the box, and the battery is the battery described above.
[0022] According to a third aspect of the present invention, the present application provides an electrical device comprising the battery pack or the battery described above.
[0023] The present application provides a diaphragm structure, a battery, a battery pack, a battery pack and an electrical device. By setting a thermal responsive material, when the diaphragm structure undergoes thermal runaway, the thermal responsive material is damaged or melted by heat and adheres to the surface of the diaphragm, which can reduce the risk of thermal runaway and improve the safety performance of the diaphragm, thereby reducing the risk of battery overheating and improving the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0025] Figure 1 Provides a schematic diagram of the diaphragm structure for the embodiment of the present application;
[0026] Figure 2 Schematic diagram of the thermal responsive material structure;
[0027] Figure 3 Schematic diagram of the thermal responsive material attaching to the diaphragm after melting.
[0028] Description of reference numerals:
[0029] 1-diaphragm; 2-thermal responsive material; 21-flame retardant; 22-adhesion layer; 3-substrate. DETAILED DESCRIPTION
[0030] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.
[0031] Lithium-ion batteries are rapidly developing and becoming increasingly popular in the industry. Their energy density has significantly increased, their cost has gradually decreased, and their application has expanded widely. However, as their usage increases, so too have related accidents. Overheating of lithium-ion battery systems can cause exothermic reactions and thermal runaway, ultimately leading to equipment failure and even fire and explosion, threatening life. Therefore, improving the safety performance of lithium-ion batteries and reducing potential safety hazards have become important driving forces for the leapfrog development of the industry. Currently, lithium-ion battery separators mostly use single-layer polyolefin separators, which have limited thermal stability. Excessive temperatures can cause the separator to shrink or melt, posing a safety hazard.
[0032] In view of this, the present application provides a diaphragm structure, the diaphragm structure comprising:
[0033] a diaphragm, wherein an accommodating space is formed inside the diaphragm;
[0034] A thermally responsive material is disposed within the housing space and is adapted to melt when the temperature reaches a predetermined value and to coat the inner surface of the diaphragm. When thermal runaway occurs, the internal temperature of the battery changes, the ambient temperature rises, and the diaphragm structure is heated. When the temperature reaches a certain value, the thermally responsive material breaks or melts and adheres to the diaphragm surface, thereby reducing the risk of thermal runaway and improving battery safety.
[0035] The contents of this application will be described in detail below with reference to the accompanying drawings so that those skilled in the art can understand the contents of this application more clearly and in detail.
[0036] The specific structure of the diaphragm and various possible implementations are described in detail below.
[0037] Figure 1 The present invention provides a schematic diagram of the diaphragm structure for the embodiment of the present invention. Figure 2 is a schematic diagram of the structure of thermal responsive materials. Figure 3 Schematic diagram of the thermal responsive material attaching to the diaphragm after melting
[0038] As shown in the figure, the diaphragm structure provided by the embodiment of the present application includes: a diaphragm, wherein the diaphragm 1 has an internal accommodation space; and a thermally responsive material 2, which is disposed within the accommodation space. The thermally responsive material 2 is adapted to melt when the heated temperature reaches a predetermined value and to cover the inner surface of the diaphragm 1, forming an adhesion layer 22. When the diaphragm structure experiences thermal runaway, the thermally responsive material 2 is damaged or melted by the heat and adheres to the surface of the diaphragm 1, forming an adhesion layer 22. The adhesion layer 22 can effectively prevent ion transmission between the two ends of the diaphragm 1, reducing the risk of thermal runaway and improving the safety performance of the diaphragm structure, thereby reducing the risk of battery overheating and improving the safety performance of the battery.
[0039] In one possible implementation, the diaphragm structure further includes a base 3, which fills the accommodation space and in which the thermally responsive material 2 is dispersed. The base 3 facilitates the thermally responsive material 2 to move within the accommodation space after melting due to heat, thereby facilitating the thermally responsive material 2 to adhere to the diaphragm 1 after melting due to heat.
[0040] In a possible implementation, the diaphragm 1 has at least two diaphragm base layers, and an accommodating space is formed between the at least two diaphragm base layers.
[0041] In one possible implementation, the thermally responsive material 2 is provided with an internal space, within which a flame retardant 21 is disposed. When the thermally responsive material 2 is damaged or melted by heat, the flame retardant 21 is released. The release of the flame retardant 21 can effectively inhibit battery combustion, thereby reducing the risk of battery overheating and improving battery safety.
[0042] In one possible implementation, the thermally responsive material 2 includes an organic material.
[0043] In a possible implementation, the material of the diaphragm 1 includes polyolefin.
[0044] In one possible implementation, the organic material includes ethylene-ethyl acetate copolymer EVA. When thermal runaway occurs, the selected ethylene-ethyl acetate copolymer EVA shell material will decompose or dissolve due to high temperature and cover the diaphragm 1. At this time, the ion channel of the diaphragm 1 will be blocked and restricted, thereby effectively blocking the lithium ion reaction. The internal electrochemical reaction of the battery will be forced to stop, avoiding heat accumulation due to continuous reaction, and effectively reducing the risk of thermal runaway.
[0045] In one possible implementation, the thermally responsive material 2 includes a thermistor material. When the temperature reaches a certain level, the thermistor material experiences a sudden increase in resistance, generating localized Joule heat. This localized Joule heat closes the pores of the separator 1, effectively blocking the lithium ion reaction and forcing the internal electrochemical reaction of the battery to stop, thus preventing heat accumulation from continuous reactions and effectively reducing the risk of thermal runaway. Different thermistor materials can be selected according to the required temperature conditions. The single-layer polyolefin diaphragm 1 is irreversible after high-temperature closure, lacks the active protection of the flame retardant 21, and is prone to chain reactions. This implementation method can achieve dual responses to temperature and flame retardancy. The release of the flame retardant 21 and the closure work synergistically to improve safety and rate performance, and inhibit thermal runaway chain reactions. The ionic conductivity of the single-layer polyolefin diaphragm 1 is about 0.9mS / cm. This implementation method can inhibit dendrite growth while taking into account high ionic conductivity and long cycle life. The dry process of the single-layer polyolefin diaphragm 1 is simple and the single-line investment is low, but it has limitations and cannot meet the needs of high energy density and high safety. The diaphragm structure can meet the needs of high energy density and high safety. The flame retardant 21 packaging amount is small and is compatible with the existing wet-process diaphragm production line. Only the coating module needs to be added, and the overall mass production cost is low.
[0046] In one possible implementation, the thermistor material includes a PTC material. When the temperature reaches 110°C-130°C, the resistance of the PTC material increases sharply, generating local Joule heat. This local Joule heat closes the pores of the separator 1, effectively blocking the lithium ion reaction. The internal electrochemical reaction of the battery is forced to stop, preventing heat accumulation due to continuous reaction and effectively reducing the risk of thermal runaway.
[0047] In one possible implementation, polydopamine is provided on the surface of the thermally responsive material 2 opposite to the diaphragm 1. It is used to improve the interfacial stability with the electrolyte and reduce the polarization overpotential. The PDA surface is rich in polar groups such as hydroxyl (-OH) and amino (-NH2), which significantly improves the wettability of the electrolyte on the material surface. At the same time, the PDA functional groups (such as catechol) can react with metal ions (such as Li + 、Zn 2+ ) coordination, reducing the desolvation energy barrier, increasing the Li+ migration number, effectively alleviating concentration polarization, and reducing the polarization overpotential.
[0048] In one possible implementation, the flame retardant 21 includes triphenyl phosphate, which is a phosphorus-based barrier. When thermal runaway occurs in the diaphragm structure, triphenyl phosphate decomposes at high temperature to generate phosphoric acid that covers the electrode surface and inhibits the free radical chain reaction.
[0049] In one possible implementation, the matrix 3 includes PVDF glue. PVDF dissolved in a solvent as the matrix 3 can evenly disperse the active substance, i.e., the organic material, and play a certain bonding role, ensuring that the distance between the organic materials is uniform and stable.
[0050] In a possible implementation, the thickness of the diaphragm 1 is 5 to 8 micrometers.
[0051] In a possible implementation, the distance between the base layers of at least two diaphragm layers 1 is 5 to 8 micrometers.
[0052] In a possible implementation, the volume of the internal space of the thermally responsive material 2 is 0.5 to 1.5 cubic micrometers.
[0053] According to the second aspect of the present invention, an embodiment of the present application further provides a battery, comprising a positive electrode sheet, a negative electrode sheet, and a diaphragm structure disposed between the positive electrode sheet and the negative electrode sheet, wherein the diaphragm structure is the diaphragm structure described above.
[0054] According to a third aspect of the present invention, an embodiment of the present application further provides a battery pack, comprising a box and a battery, wherein the battery is placed in the box, and the battery is the battery described above.
[0055] According to a fourth aspect of the present invention, the present application provides an electrical device comprising the battery pack and the battery described above.
[0056] The electric equipment also includes the electric device. The battery assembly or battery device is used to provide power to the electric device.
[0057] The electrical equipment in the embodiments of the present application may be a vehicle. For example, the vehicle may be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. Accordingly, the electrical device may be the vehicle's drive mechanism or the vehicle's control system.
[0058] In addition, the electrical equipment may also be other energy storage devices, such as energy storage power stations, energy storage cabinets, mobile phones, portable devices, laptops, electric toys, electric tools, ships and spacecraft, etc., among which spacecraft may include airplanes, rockets, space shuttles or spacecraft.
[0059] It should be noted that references in this specification to "one embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not necessarily every embodiment includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not.
[0060] Generally speaking, terms should be understood, at least in part, based on the context in which they are used. For example, as used herein, the term "one or more" can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense, depending at least in part on the context. Similarly, terms such as "a," "an," or "the" can also be understood to convey either singular or plural usage, depending at least in part on the context.
[0061] It should be readily understood that “between,” “above,” and “over” in this application should be interpreted in the broadest manner, such that “between” means not only “directly between something,” but also includes “in something” with intervening features or layers therebetween, and “above” or “over” includes not only the meaning of “above” or “over,” but also includes the meaning of “above” or “over” with no intervening features or layers therebetween (i.e., directly on something).
[0062] Additionally, spatially relative terms, such as "below," "beneath," "beneath," "above," and the like, may be used herein for ease of description to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be in other orientations (rotated 90° or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.
[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A diaphragm structure, characterized in that: The diaphragm structure comprises: a diaphragm, wherein an accommodating space is formed inside the diaphragm; A thermally responsive material is disposed in the accommodating space and is adapted to melt when the heated temperature reaches a predetermined value and to cover the inner surface of the diaphragm.
2. The diaphragm structure according to claim 1, characterized in that The diaphragm structure further includes a matrix, the matrix fills the accommodating space, and the thermal response material is dispersed in the matrix.
3. The diaphragm structure according to claim 1, characterized in that The diaphragm has at least two diaphragm base layers, and the accommodating space is formed between the at least two diaphragm base layers.
4. The diaphragm structure according to claim 1, characterized in that The thermally responsive material is provided with an internal space, and a flame retardant is provided in the internal space.
5. The diaphragm structure according to claim 1, characterized in that The thermally responsive material includes an organic material.
6. The diaphragm structure according to claim 1, characterized in that The material of the separator includes polyolefin.
7. The diaphragm structure according to claim 5, characterized in that The organic material includes ethylene-vinyl acetate copolymer (EVA).
8. The diaphragm structure according to claim 1, characterized in that The thermally responsive material includes a thermistor material.
9. The diaphragm structure according to claim 8, characterized in that: The thermistor material includes a PTC material.
10. The diaphragm structure according to claim 1, characterized in that Polydopamine is provided on the surface of the thermal response material opposite to the diaphragm.
11. The diaphragm structure according to claim 4, characterized in that The flame retardant includes triphenyl phosphate.
12. The diaphragm structure according to claim 2, characterized in that: The matrix includes PVDF glue.
13. The diaphragm structure according to claim 1, characterized in that The thickness of the diaphragm is 5 to 8 microns.
14. The diaphragm structure according to claim 3, characterized in that The distance between at least two layers of the diaphragm base layer is 5 to 8 microns.
15. The diaphragm structure according to claim 4, characterized in that The volume of the internal space of the thermal response material is 0.5 to 1.5 cubic micrometers.
16. A battery, characterized in that: The invention comprises a positive electrode sheet, a negative electrode sheet and a diaphragm structure arranged between the positive electrode sheet and the negative electrode sheet, wherein the diaphragm structure is the diaphragm structure according to any one of claims 1 to 15.
17. A battery pack, characterized in that: The invention comprises a box and a battery, wherein the battery is placed in the box, and the battery is the battery according to claim 16.
18. An electrical device, characterized in that: Comprising the battery pack according to claim 17 or the battery according to claim 16.