Polyester composite membranes and their preparation methods, composite current collectors and their preparation methods, electrodes and their applications

Abstract

This application relates to the field of electrochemical technology, specifically to polyester composite films and their preparation methods, composite current collectors and their preparation methods, electrodes and their applications. The polyester composite film of this application comprises: a polyester substrate layer and a first surface layer and a second surface layer respectively disposed on opposite sides of the polyester substrate layer; the polyester substrate layer comprises, by weight, 90 to 99 parts of polyester material and 1 to 10 parts of photo-straining material; the first and second surface layers comprise polyethylene terephthalate polymers; the transmittance of the first surface layer, the second surface layer, and the polyester material is independently 92% to 99%; the photo-straining material comprises one or more of barium titanate ceramics, lead zirconate titanate ceramics, PI / CNTs photosensitive composite materials, PEEK / anthraquinone photosensitive composite materials, MIL-101 chromium metal-organic frameworks, and UiO-66-NH2 / ZnO composite materials. The polyester composite film can easily break under high-destructive external forces such as battery breakdown and battery collision, effectively suppressing thermal runaway.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, specifically to polyester composite membranes and their preparation methods, composite current collectors and their preparation methods, and electrodes and their applications. Background Technology

[0002] Current collectors are an important component of secondary batteries. They help reduce the battery's internal resistance and improve its coulombic efficiency, cycle stability, and rate performance. The main function of the current collector is to collect and output the current generated by the active material and to input the electrode current to the active material.

[0003] To reduce the weight of current collectors and increase battery energy density, composite current collectors have emerged. A composite current collector is a "sandwich" structure composite material, with a polymer substrate in the middle and a metal layer on each side. Currently, the polymer substrate for composite current collectors is generally polyethylene terephthalate (PET). PET has an elongation at break exceeding 90%. This high elongation means that the composite current collector cannot disconnect in time when subjected to destructive forces, meaning it can maintain battery conductivity even under destructive forces. This leads to short circuits, increased heat generation, and limited ability to suppress battery thermal runaway. Summary of the Invention

[0004] Based on this, this application provides a polyester composite film and its preparation method, a composite current collector and its preparation method, an electrode and its application. The polyester composite film provided in this application can be used as the intermediate layer of the composite current collector. The composite current collector obtained in this way can make the battery more easily break under the external force of battery breakdown, battery collision and other destructive forces, thereby effectively suppressing the phenomenon of battery thermal runaway.

[0005] A first aspect of this application provides a polyester composite film, comprising: a polyester base layer and a first surface layer and a second surface layer respectively disposed on opposite sides of the polyester base layer;

[0006] The components of the polyester substrate layer, by weight, include: 90 to 99 parts of polyester material and 1 to 10 parts of photo-strain material;

[0007] The components of the first and second surface layers include polyterephthalate polymers;

[0008] The light transmittance of the first surface layer, the second surface layer, and the polyester material is independently 92%~99%; the photo-strained material includes one or more of barium titanate ceramics, lead zirconate titanate ceramics, PI / CNTs photosensitive composite materials, PEEK / anthraquinone photosensitive composite materials, MIL-101 chromium metal-organic frameworks, and UiO-66-NH2 / ZnO composite materials.

[0009] In one embodiment, the first and second surface layers are porous structures.

[0010] In one embodiment, the raw material components for preparing the first surface layer and the second surface layer each independently comprise, by weight: 5 to 30 parts of an inorganic pore-forming agent and 70 to 95 parts of a polyterephthalate polymer.

[0011] In one embodiment, the polyterephthalate polymer, by weight, includes one or more of polyethylene terephthalate, poly(1,4-cyclohexanediethanol terephthalate), and polyethylene terephthalate-1,4-cyclohexanediethanol terephthalate.

[0012] In one embodiment, the inorganic pore-forming agent includes one or more of alumina, silica, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, lead sulfate, and zinc oxide.

[0013] In one embodiment, the D50 particle size of the inorganic pore-forming agent is 0.01 μm-2 μm.

[0014] In one embodiment, the thickness ratio of the first surface layer to the polyester base layer is (1~1.5):(3~4).

[0015] In one embodiment, the thickness ratio of the second surface layer to the polyester base layer is (1~1.5):(3~4).

[0016] In one embodiment, the polyester material includes one or more of polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanediethanol and polyethylene terephthalate-1,4-cyclohexanediethanol.

[0017] A second aspect of this application provides a method for preparing a polyester composite film, the polyester composite film comprising: a polyester base layer and a first surface layer and a second surface layer respectively disposed on opposite sides of the polyester base layer, the preparation method comprising the following steps:

[0018] The raw materials of the first surface layer, the polyester base layer and the second surface layer are mixed independently, and after melt slicing, the first pellet, the second pellet and the third pellet are prepared respectively.

[0019] The first granulated material, the second granulated material, and the third granulated material are melt-mixed, co-extruded, and then stretched to prepare a polyester composite film matrix.

[0020] The polyester substrate layer comprises, by weight, 90 to 99 parts of polyester material and 1 to 10 parts of photo-straining material; the photo-straining material includes one or more of barium titanate ceramic, lead zirconate titanate ceramic, PI / CNTs photosensitive composite material, PEEK / anthraquinone photosensitive composite material, MIL-101 chromium metal-organic framework, and UiO-66-NH2 / ZnO composite material; the first and second surface layers comprise polyethylene terephthalate polymers; the light transmittance of the first surface layer, the second surface layer, and the polyester material is independently 92% to 99%;

[0021] The polyester composite film substrate is subjected to light irradiation treatment to prepare a polyester composite film. In one embodiment, the raw material components for preparing the first surface layer and the second surface layer each independently include: 5 parts to 30 parts of an inorganic pore-forming agent and 70 parts to 95 parts of a polyethylene terephthalate polymer.

[0022] In one embodiment, the preparation method includes, before the light irradiation treatment, acid washing the polyester composite film substrate to form a porous structure in the first surface layer and the second surface layer.

[0023] In one embodiment, the pickling step includes: pickling the polyester composite film substrate with an acidic elution solvent; wherein the acidic elution solvent includes one or more of hydrochloric acid, sulfuric acid, oxalic acid, citric acid, acetic acid, and hydrofluoric acid.

[0024] In one embodiment, the process parameters of the light irradiation treatment include: the irradiation wavelength is 100nm~1000nm, and the irradiation time is 10s~10min.

[0025] In one embodiment, the photo-strained material is barium titanate ceramic, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 240nm~260nm.

[0026] In one embodiment, the photo-strained material is lead zirconate titanate ceramic, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 300nm~400nm.

[0027] In one embodiment, the photo-strained material is a PI / CNTs photosensitive composite material, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is infrared light, and the wavelength of the irradiation light is 800nm~1000nm.

[0028] In one embodiment, the photo-strained material is a PEEK / anthraquinone photosensitive composite material, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 350nm~370nm.

[0029] In one embodiment, the photo-strained material is a MIL-101 chromium metal-organic framework, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 340nm~365nm.

[0030] In one embodiment, the photo-strained material is a UiO-66-NH2 / ZnO composite material, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 300nm~400nm.

[0031] A third aspect of this application provides a method for preparing a composite current collector, comprising the following steps:

[0032] At least one surface of the polyester composite film prepared by the preparation method described in the second aspect of this application is deposited with a metal layer.

[0033] The time interval between the light irradiation treatment and the deposition of the metal layer is 0.1 minutes to 30 minutes.

[0034] A fourth aspect of this application provides a composite current collector, comprising a polyester composite film as described in any embodiment of the first aspect of this application and a metal layer disposed on at least one surface of the polyester composite film.

[0035] In one embodiment, the material of the metal layer includes one or more of aluminum and aluminum alloys.

[0036] In one embodiment, the thickness of the metal layer is 0.8 mm to 1.2 mm.

[0037] A fifth aspect of this application provides an electrode comprising the composite current collector described in the fourth aspect of this application or the composite current collector prepared by the preparation method described in the third aspect of this application.

[0038] A sixth aspect of this application provides a battery including the electrodes described in the fifth aspect of this application.

[0039] The polyester composite film provided in this application has at least the following beneficial effects:

[0040] The polyester composite film provided in this application includes a polyester base layer and a first surface layer and a second surface layer respectively disposed on opposite sides of the polyester base layer. The polyester base layer comprises a specific type of photo-straining material. This photo-straining material and a specific weight proportion of polyester material work synergistically. Under conditions where the first surface layer, the second surface layer, and the polyester material have light transmittance, the photo-straining material, under light irradiation, can alter the stress distribution uniformity of the polyester base layer, thereby causing localized stress concentration and reducing the overall elongation of the polyester composite film. Therefore, under the damaging external forces such as battery breakdown or battery collision, the polyester composite film can more easily break, preventing battery short circuits and increased heat generation, thus effectively suppressing battery thermal runaway and significantly improving battery safety performance.

[0041] The first and second surface layers prevent the photo-strain material from being exposed on the surface of the polyester composite film, thereby preventing the photo-strain material from falling off or causing damage to the film surface due to friction of the photo-strain material after the polyester composite film is rolled up. Furthermore, the components of the first and second surface layers include polyterephthalate polymers, which have excellent compatibility with the polyester substrate layer, thereby effectively enhancing the interlayer adhesion and preventing the polyester composite film from delaminating when the photo-strain material undergoes volume changes. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the structure of a polyester composite film provided as an example of this application.

[0044] In the figure, 10 is the polyester composite film; 100 is the polyester base layer; 200 is the first surface layer; and 300 is the second surface layer. Detailed Implementation

[0045] The following detailed description, in conjunction with specific embodiments, provides a more complete and clear account of the polyester composite film and its preparation method, the composite current collector and its preparation method, and the electrode and its application. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0046] See Figure 1In a first aspect, this application provides a polyester composite film 10, comprising: a polyester base layer 100 and a first surface layer 200 and a second surface layer 300 respectively disposed on opposite sides of the polyester base layer 100.

[0047] In one example, the polyester substrate 100 comprises, by weight, 90 to 99 parts of polyester material and 1 to 10 parts of photo-strained material.

[0048] In one example, the photo-strained material includes one or more of barium titanate ceramics, lead zirconate titanate ceramics, PI / CNTs photosensitive composites, PEEK / anthraquinone photosensitive composites, MIL-101 chromium metal-organic frameworks, and UiO-66-NH2 / ZnO composites.

[0049] The polyester substrate layer comprises specific types of photo-straining materials. These photo-straining materials and a specific weight proportion of polyester material synergistically alter the stress distribution uniformity of the polyester substrate layer, thereby causing localized stress concentration and reducing the overall elongation of the polyester composite film. Barium titanate ceramics are ceramic materials with barium titanate (BaTiO3) or its solid solution as the main crystalline phase, possessing an ABO3 perovskite structure. Lead zirconate titanate ceramics are composed of elements such as lead, zirconium, titanium, and oxygen, and also possess a perovskite structure. Photoirradiation induces changes in the internal electronic structure of these ceramic materials, causing ion shifts within their crystal structure. Simultaneously, photoirradiation may introduce defects such as oxygen vacancies, affecting the internal charge distribution and stress state, leading to volume changes in the material.

[0050] PI / CNTs photosensitive composite material is a composite material composed of polyimide (PI) and carbon nanotubes (CNTs). It exhibits photosensitivity and undergoes specific physicochemical changes under light irradiation. After absorbing photon energy, the photosensitive groups in the PI molecular chain undergo cross-linking reactions or conformational changes, altering the arrangement and interactions of the molecular chains, thereby changing the microstructure of the material. On the other hand, CNTs possess excellent photothermal conversion properties; after absorbing light, they convert light energy into heat energy, causing a local temperature increase in the material and resulting in thermal expansion, which in turn causes a volume change in the polyester substrate. Therefore, the combination of these materials results in a significant volume change in the PI / CNTs photosensitive composite material after light irradiation, which in turn affects the overall stress distribution of the polyester composite film and its elongation at break.

[0051] PEEK / anthraquinone photosensitizer is a novel composite material composed of polyether ether ketone (PEEK) and anthraquinone photosensitizers. Anthraquinone undergoes a photochemical reaction under light irradiation, generating photogenerated carriers and free radicals. These changes alter the charge distribution and chemical potential within the material, leading to conformational changes in the molecular chains and alterations in intermolecular forces. Simultaneously, PEEK may also absorb heat and undergo thermal expansion under light irradiation, resulting in volume changes in the PEEK / anthraquinone photosensitizer composite material under light irradiation.

[0052] MIL-101 chromium metal-organic framework is a metal-organic framework material composed of chromium ions and terephthalic acid ligands. Light irradiation causes electronic transitions in the metal ions or ligands within the material, altering the properties and strength of their chemical bonds and consequently adjusting their crystal structure. Furthermore, light irradiation induces internal thermal effects, resulting in volume changes within the material.

[0053] UiO-66-NH2 / ZnO composite material is a composite material composed of a metal-organic framework UiO-66-NH2 and nano-zinc oxide (ZnO). Light irradiation causes UiO-66-NH2 and ZnO to generate photogenerated charge carriers, leading to changes in the internal charge distribution of the material and generating internal stress.

[0054] Therefore, the aforementioned materials undergo volume or stress changes under light irradiation, affecting the overall stress distribution of the polyester base film and consequently its elongation at break. Understandably, the weight percentage of the polyester material can be selected from any value between 1 and 10 parts. For example, the weight percentage of the photostraining material includes, but is not limited to, 1, 3, 5, 7, 9, or 10 parts, or any range formed by any two of the above points as endpoints. The weight percentage of the polyester material can be selected from any value between 90 and 99 parts. For example, the weight percentage of the polyester material includes, but is not limited to, 90, 93, 95, 97, 98, or 99 parts. Limiting the composition of the polyester base layer within the above ranges ensures that the photostraining material exhibits sufficient volume and stress changes while preserving the tensile strength of the polyester composite film. If the content of photo-straining material is too low, the volume and stress changes will be limited, which means that the effect on the elongation at break of the polyester composite film will be limited. If the content of photo-straining material is too high, the film-forming properties of the polyester composite film will decrease, and the strength of the polyester composite film will also decrease.

[0055] In one example, the polyester material includes one or more of polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanediethanolate, and polyethylene terephthalate-1,4-cyclohexanediethanolate.

[0056] In one example, the components of the first and second surface layers include polyterephthalate polymers.

[0057] The first and second surface layers prevent the photo-strain material from being exposed on the surface of the polyester composite film, thus avoiding damage to the film surface caused by the photo-strain material detaching or rubbing against the film surface after the polyester composite film is rolled up. Furthermore, the components of the first and second surface layers include polyterephthalate polymers, which have excellent compatibility with the polyester substrate layer, thereby effectively enhancing the interlayer adhesion and preventing delamination of the polyester composite film when the photo-strain material undergoes volume changes.

[0058] In one example, the transmittance of the first surface layer, the second surface layer, and the polyester material is independently 92% to 99%. The high transmittance of the first surface layer, the second surface layer, and the polyester material allows the photo-strained material to be fully irradiated, ensuring volume or stress changes. Understandably, the transmittance of the first surface layer, the second surface layer, and the polyester material is independently, but not limited to, 92%, 93%, 94%, 95%, 96%, 97%, 98%, and 99%. The transmittance of the first surface layer, the second surface layer, and the polyester material can be adjusted by controlling the crystallinity of the polymer material and process parameters such as the forming temperature, pressure, and speed during film stretching.

[0059] In one example, the first and second surface layers have a porous structure. The components of the first and second surface layers include polyterephthalate polymers.

[0060] In one example, the porous structure of the first and second surface layers was obtained by acid washing with an inorganic pore-forming agent.

[0061] The first and second surface layers consist of polyethylene terephthalate polymers, which exhibit excellent compatibility with the polyester substrate, effectively enhancing interlayer adhesion and preventing delamination. Simultaneously, the porous structure of the first and second surface layers increases the surface roughness of the polyester composite film, thereby increasing its adhesion to the metal layer. Furthermore, the porous structure of the first and second surface layers disrupts the continuity and homogeneity of the material. When the battery is subjected to destructive forces, the stress values ​​in the stress concentration areas of the first and second surface layers are much higher than the average stress, preventing further significant plastic deformation and reducing elongation. At the same time, the porous structure of the first and second surface layers reduces energy loss during light irradiation, allowing the photo-strained material to be fully irradiated and ensuring volume or stress changes. Moreover, the porous structure absorbs some deformation during volume changes in the photo-strained material, preventing the first and second surface layers from separating from the polyester substrate.

[0062] It should be noted that, since the photo-strain material is set in the polyester substrate, there is less reaction between the pickling liquid and the photo-strain material during the pickling process, thus avoiding the pickling process from affecting the effect of the photo-strain material.

[0063] In one example, the raw material components for preparing the first and second surface layers, by weight, each independently comprise: 5 to 30 parts of an inorganic pore-forming agent and 70 to 95 parts of a polyterephthalate polymer.

[0064] The weight percentage of the inorganic pore-forming agent plays a crucial role in ensuring the porosity of the porous structure in the first and second surface layers. The addition of the inorganic pore-forming agent can provide an anchor for the formation of the porous structure in the first and second surface layers, and can influence the pore distribution density and pore size of the porous structure in the first and second surface layers.

[0065] For example, the weight parts of the non-mechanized pore-forming agent include, but are not limited to, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, or any two of the above values ​​as endpoints. The weight parts of the polyethylene terephthalate polymer include, but are not limited to, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, 85 parts, 88 parts, 90 parts, 92 parts, 95 parts, 98 parts, or 100 parts, or any two of the above values ​​as endpoints. Limiting the weight parts of the raw material components for the preparation of the first and second surface layers ensures both the pore distribution density and film-forming properties of the first and second surface layers. If the content of the non-mechanized pore-forming agent is slightly less, the pore distribution density of the first and second surface layers will be slightly lower, thus having a limited impact on the overall elongation at break of the polyester composite film. If the content of the non-mechanical pore-forming agent is slightly too high, it will lead to a decrease in the film-forming properties of the first and second surface layers, increasing the risk of film breakage.

[0066] In one example, the inorganic pore-forming agent includes one or more of alumina, silica, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, lead sulfate, and zinc oxide.

[0067] In one example, the D50 particle size of the inorganic pore-forming agent is 0.01 μm to 2 μm. A D50 particle size within this range helps to form uniformly sized and regularly shaped pores in the first and second surface layers.

[0068] In one example, the polyterephthalate polymer, by weight, includes one or more of polyethylene terephthalate, poly(1,4-cyclohexanediethanol) terephthalate, and polyethylene terephthalate-1,4-cyclohexanediethanol.

[0069] In one example, the thickness ratio of the first surface layer to the polyester substrate layer is (1~1.5):(3~4). Further, the thickness ratio of the first surface layer to the polyester substrate layer includes, but is not limited to, 1:3, 1:3.5, 1:4, 1.2:3, 1.2:3.5, 1.2:4, 1.5:3, 1.5:3.5, or 1.5:4, or any two of the above values ​​as endpoints within a range.

[0070] In one example, the thickness ratio of the second surface layer to the polyester substrate layer is (1~1.5):(3~4). Further, the thickness ratio of the second surface layer to the polyester substrate layer includes, but is not limited to, 1:3, 1:3.5, 1:4, 1.2:3, 1.2:3.5, 1.2:4, 1.5:3, 1.5:3.5, or 1.5:4, or any two of the above values ​​as endpoints within a range.

[0071] When the thickness ratios of the first surface layer and the polyester substrate layer, and the second surface layer and the polyester substrate layer are within the aforementioned ranges, it is beneficial to leverage the synergistic effect of the polyester substrate layer and the surface layer, creating a reasonable stress distribution between them. This ensures the polyester composite film's resistance to tensile failure while reducing its elongation at break.

[0072] In one example, the thickness of the polyester substrate layer is 3μm to 15μm. Limiting the thickness of the polyester substrate layer to this range provides the composite current collector with ideal mechanical strength and flexibility, effectively preventing cracking and wrinkling, and greatly enhancing structural stability. Furthermore, it facilitates achieving lightweight design goals, reduces material costs, and increases battery energy density.

[0073] A second aspect of this application provides a method for preparing a polyester composite film as described in any example of the first aspect of this application, comprising the following steps:

[0074] S10: The raw materials of the first surface layer, the polyester base layer and the second surface layer are mixed independently, and after melt slicing, the first pellet, the second pellet and the third pellet are prepared respectively.

[0075] S20: The first granulated material, the second granulated material, and the third granulated material are melt-mixed, co-extruded, and then stretched to prepare a polyester composite film matrix; wherein, the polyester composite film matrix includes a polyester base layer, a first surface layer, and a second surface layer. The first surface layer and the second surface layer are located on opposite sides of the polyester base layer.

[0076] S30: The polyester composite film substrate is subjected to light irradiation treatment to form a porous structure in the first surface layer and the second surface layer, thereby preparing a polyester composite film.

[0077] Understandably, the polyester composite film includes: a polyester base layer and a first surface layer and a second surface layer respectively disposed on opposite sides of the polyester base layer.

[0078] In one example, the preparation method includes, before the light irradiation treatment, acid washing the polyester composite film substrate to form a porous structure in the first and second surface layers.

[0079] Furthermore, the pickling step includes: pickling the polyester composite film substrate with an acid-based elution solvent.

[0080] The acid elution solvent includes one or more of hydrochloric acid, sulfuric acid, oxalic acid, citric acid, acetic acid, and hydrofluoric acid.

[0081] The aforementioned acid-based eluents not only clean the inorganic pore-forming agents on the surfaces of the first and second surface layers, but also penetrate into the interior of these layers to remove the internal inorganic pore-forming agents. This results in the formation of pores within a shorter pickling time, reducing the impact of prolonged contact with acid-based eluents on the polyester composite film. The formation of these pores effectively reduces the elongation of the polyester composite film while preserving its tensile strength. Furthermore, the presence of these pores increases the surface roughness of the polyester base film, enhancing its adhesion to the metal layer.

[0082] In one example, the first and second surface layers do not include photosensitive material. This application has found that when photosensitive material is added to the first or second surface layer, its compatibility with inorganic pore-forming agents is slightly poor, which can affect the film formation of the first and second surface layers. Furthermore, since the first or second surface layer undergoes an acid washing step, if the photosensitive material is disposed on the first or second surface layer, the acidic elution solvent will react with the photosensitive material, affecting its effectiveness. By placing the photosensitive material within the polyester substrate layer, the effects of acid washing on the photosensitive material can be effectively avoided.

[0083] In one example, the process parameters for the photo-irradiation treatment include: an irradiation wavelength of 100 nm to 1000 nm and an irradiation time of 10 s to 10 min. The irradiation time plays a crucial role in ensuring the photo-straining effect and avoiding thermal damage to the polyester composite film. If the irradiation time is slightly shorter, the volume change and local strain of the photo-strained material are slightly lower, and its impact on the elongation of the polyester composite film is limited. If the irradiation time is slightly longer, the thermal damage to the polyester composite film is slightly higher, affecting the strength of the polyester composite film and the subsequent metal coating effect.

[0084] Photoirradiation treatment can cause changes in volume or stress in the photo-strained material in the polyester substrate, thereby affecting the overall stress distribution of the polyester composite film and ensuring that the elongation at break of the polyester composite film is moderate.

[0085] This application discovers that different types of photostrain materials have different optical absorption characteristics and energy level structures. Only by selecting appropriate irradiation light and corresponding wavelengths that match them can the photostrain materials be effectively excited to produce the expected strain response.

[0086] For example, the photo-strained material is barium titanate ceramic, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 240nm~260nm.

[0087] For example, the photo-strained material is lead zirconate titanate ceramic, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 300nm~400nm.

[0088] For example, the photo-strained material is a PI / CNTs photosensitive composite material, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is infrared light, and the wavelength of the irradiation light is 800nm~1000nm.

[0089] For example, the photo-strained material is a PEEK / anthraquinone photosensitive composite material, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 350nm~370nm.

[0090] For example, the photo-strained material is a MIL-101 chromium metal-organic framework, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 340nm~365nm.

[0091] For example, the photo-strained material is a UiO-66-NH2 / ZnO composite material, and the process parameters of the photo-irradiation treatment include: the type of irradiation light is ultraviolet light, and the wavelength of the irradiation light is 300nm~400nm.

[0092] A third aspect of this application provides a composite current collector comprising a polyester composite film as described in any of the first aspects of this application and a metal layer disposed on at least one surface of the polyester composite film.

[0093] In one example, the material of the metal layer includes one or more of aluminum and aluminum alloys.

[0094] This application discovers that internal short circuits between the negative electrode material and the positive electrode material, as well as between the positive electrode aluminum current collector and the positive electrode material, in battery thermal runaway are directly related to the positive electrode aluminum current collector. The elongation of pure aluminum material is between 10% and 30%, while the elongation of PET material generally exceeds 90%. Therefore, the overall breaking elongation of the composite current collector aluminum foil is mainly determined by the PET film material. However, excessively high breaking elongation prevents the composite aluminum foil from breaking immediately under external force. The polyester composite film and composite current collector provided in this application can reduce their elongation, thereby preventing battery thermal runaway.

[0095] In one example, the thickness of the metal layer is 0.8µm to 1.2µm. This thickness range ensures that the metal layer has good conductivity, effectively reducing the battery's internal resistance and improving the battery's charge / discharge efficiency and performance stability.

[0096] This application also provides a method for preparing a composite current collector, comprising the following steps:

[0097] At least one surface of the polyester composite film prepared by the preparation method described in any example of the second aspect of this application is deposited with a metal layer. The time interval between the light irradiation treatment and the deposition of the metal layer is 0.1 minutes to 30 minutes. Further, the method of depositing the metal layer includes, but is not limited to, vacuum evaporation.

[0098] When a polyester composite film is irradiated with light, the photo-strained material in the polyester substrate layer undergoes volume changes and localized strain. These stress changes cause fine deformations and wrinkles to form on the surface of the polyester composite film. This application discovers that when the aforementioned polyester composite film undergoes vacuum evaporation, the deformations and wrinkles formed on its surface are smoothed out under the high temperature of the evaporation chamber and the action of the flattening rollers, thereby effectively reducing the impact on the adhesion of the metal layer.

[0099] Furthermore, the time interval between the photo-irradiation treatment and the deposition of the metal layer is set between 0.1 minutes and 30 minutes. This means that the photo-irradiated polyester composite film can directly enter the metal deposition process without requiring an additional winding step. This effectively avoids the problem of the minute strains induced by photo-induced strain in the polyester composite film accumulating and forming wrinkles and deformations under winding tension, and ultimately becoming permanent wrinkles under prolonged winding pressure.

[0100] Furthermore, the method for preparing the composite current collector in this application involves depositing a metal layer on a polyester composite film after it has undergone light irradiation treatment; that is, the light irradiation treatment step is performed first, followed by the metal layer preparation step. This effectively avoids the problem that the metal layer on the surface of the polyester composite film is opaque and reflects most of the ultraviolet / infrared light, thus failing to induce photo-induced strain.

[0101] In one example, the metal layer is made of aluminum.

[0102] For example, the equipment for vacuum evaporation includes, but is not limited to, evaporation boats and wire feeding systems. More specifically, the equipment for vacuum evaporation consists of 72 evaporation boats. The wire feeding system feeds aluminum wires above the evaporation boats, where the heat generated by heating the evaporation boats melts the aluminum wires. The molten aluminum drips onto the evaporation boats, where it further evaporates to form gas, ultimately depositing onto the polyester composite film. For example, the diameter of the aluminum wires is 1.5 mm to 2.5 mm.

[0103] In one example, the process parameters for the vacuum evaporation include: the wire feeding speed of the wire feeding system is 400 mm / min to 500 mm / min. For example, the wire feeding speed of the wire feeding system includes, but is not limited to, 400 mm / min, 410 mm / min, 420 mm / min, 430 mm / min, 440 mm / min, 450 mm / min, 460 mm / min, 470 mm / min, 480 mm / min, 490 mm / min, or 500 mm / min, or any two of the above values ​​as endpoints.

[0104] In one example, the evaporation rate of the vacuum evaporation is 10 m / min to 20 m / min. An evaporation rate within this range ensures production efficiency while maintaining a high yield of the evaporated product, and avoids excessively high production costs. For example, the evaporation rate includes, but is not limited to, 10 m / min, 12 m / min, 15 m / min, 18 m / min, or 20 m / min, or any two of the above values ​​as endpoints.

[0105] In one example, the evaporation power of the vacuum evaporation is 7kW to 12kW. The evaporation power of vacuum evaporation is generally around 5kW. The evaporation power in this application, within the above range, can ensure sufficient heat treatment effect. If the evaporation power is too high, it will lead to excessive thermal damage to the polymer composite film, and its tensile strength will be significantly reduced. If the evaporation power is too low, it will result in insufficient crystallinity of the polymer composite film, leading to a negligible decrease in its elongation. For example, the evaporation power of the vacuum evaporation includes, but is not limited to, 7 kW, 7.5 kW, 8 kW, 8.5 kW, 9 kW, 9.5 kW, 10 kW, 10.5 kW, 11 kW, 11.5 kW, or 12 kW, or any two of the above values ​​within the range.

[0106] In one example, the temperature of the vacuum evaporation main roller is -20℃ to 0℃. The temperature of the evaporation main roller within this range works in conjunction with the evaporation power to ensure sufficient heat ironing effect. For example, the temperature of the vacuum evaporation main roller includes, but is not limited to, -20℃, -18℃, -16℃, -14℃, -12℃, -10℃, -8℃, -6℃, -4℃, -2℃, or 0℃, or any two of these values. If the temperature of the evaporation main roller is too low, the cooling effect on the polyester composite film is significant, resulting in insufficient heat ironing and flattening. In this case, the deformation and wrinkles caused by uneven stress distribution due to photo-induced strain cannot be fully ironed and flattened, thus affecting the appearance quality of the composite aluminum foil. If the temperature of the evaporation main roller is too high, the heat cannot be dissipated in time, leading to excessive thermal damage to the polyester composite film, significantly reducing its tensile strength and exacerbating its appearance deterioration.

[0107] In one example, the winding tension and unwinding tension of the vacuum evaporation are each independently between 100N and 300N. Within this range, the winding and unwinding tensions can both accelerate and optimize the heat treatment effect while ensuring good winding effect and appearance quality. For example, the winding tension and unwinding tension of the vacuum evaporation are independently, but not limited to, 100N, 110N, 120N, 150N, 180N, 200N, 220N, 250N, 270N, 280N, or 300N, or any two of the above values ​​as endpoints within a range. This application has found that excessively high or low winding tension can affect the heat-ironing and flattening effect on the polyester composite film.

[0108] In one example, the distance between the evaporation boat and the polymer composite film in the vacuum evaporation process is 250mm to 350mm. This distance ensures the heat treatment effect while preventing excessive thermal damage to the polymer composite film. For example, the distance between the evaporation boat and the polymer composite film may include, but is not limited to, 250mm, 270mm, 290mm, 310mm, 330mm, or 350mm, or any two of these values ​​as endpoints.

[0109] A fifth aspect of this application provides an electrode comprising the composite current collector described in the fourth aspect of this application or the composite current collector prepared by the preparation method described in the third aspect of this application.

[0110] A sixth aspect of this application provides a battery including the electrodes described in the fifth aspect of this application.

[0111] A seventh aspect of this application provides an electrical device comprising the battery described in the fifth aspect.

[0112] The following detailed embodiments illustrate this application in more detail. It should also be understood that the following embodiments are for further explanation only and should not be construed as limiting the scope of protection of this application. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of this application fall within the scope of protection of this application. The specific process parameters, etc., in the following embodiments are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the range based on the description herein, and are not necessarily limited to the specific values ​​in the embodiments below.

[0113] Example 1

[0114] Example 1 of this application provides a polyester composite film and its preparation method, and a composite current collector and its preparation method.

[0115] Polyester composite film:

[0116] (1) Forming a polyester composite membrane substrate: The polyester composite membrane substrate includes a polyester base layer and a first surface layer and a second surface layer respectively disposed on opposite sides of the polyester base layer. The raw material components of the polyester base layer, by weight, include: 95 parts of PET material and 5 parts of photo-strained material (barium titanate ceramic). The raw material components of the first and second surface layers, by weight, include: 20 parts of an inorganic pore-forming agent (D50 particle size of 1 μm) calcium sulfate and 80 parts of PET material. The thickness of the polyester base layer is 6 μm; the thickness ratio of the first surface layer to the polyester base layer is 1.0:4.0, and the thickness ratio of the second surface layer to the polyester base layer is 1.0:4.0.

[0117] (2) The polyester composite film substrate was acid-washed with hydrochloric acid to remove the inorganic pore-forming agent, forming a porous structure in the first and second surface layers. Then, the polyester composite film substrate was subjected to light irradiation treatment: the irradiation light was ultraviolet light with a wavelength of 250 nm and an irradiation time of 2 min, causing strain or volume change in the polyester substrate layer to prepare the polyester composite film. The light transmittance of the PET material, the first surface layer, and the second surface layer was 96%.

[0118] Composite current collector:

[0119] Using 72 evaporation boats and 2mm diameter aluminum wires, aluminum wires were vacuum-deposited onto opposite sides of the polyester composite film to prepare a first metal layer and a second metal layer respectively (the time interval between the formation of the first metal layer and the light irradiation treatment was 15min). The first metal layer was set on the side of the first surface layer away from the polyester substrate layer, and the second metal layer was set on the side of the second surface layer away from the polyester substrate layer. The thickness of the first metal layer and the second metal layer was 1μm; thus, a composite current collector was obtained.

[0120] The process parameters for vacuum evaporation include: aluminum wire feeding speed of 450 mm / min, evaporation rate of 15 m / min, evaporation power of 8 kW, evaporation main roller temperature of -10℃, evaporation winding tension of 200 N, and distance between the evaporation boat and the polymer composite film in vacuum evaporation of 300 mm.

[0121] Example 2

[0122] Example 2 is basically the same as Example 1, the main difference being that the photo-straining material added in Example 2 is MIL-101 chromium metal-organic framework.

[0123] The type of irradiation light is ultraviolet light, the wavelength of the irradiation light is 365nm, and the irradiation time is 2min.

[0124] Example 3

[0125] Example 3 is basically the same as Example 1, the main difference being that the photo-straining material added in Example 3 is a PEEK / anthraquinone photosensitive composite material.

[0126] The type of irradiation light is ultraviolet light, the wavelength of the irradiation light is 350nm, and the irradiation time is 5min.

[0127] Example 4

[0128] Example 4 is basically the same as Example 1, the main difference being that the type of inorganic pore-forming agent added in Example 4 is calcium carbonate.

[0129] Example 5

[0130] Example 5 is basically the same as Example 1, the main difference being that the raw material components of the first and second surface layers in Example 5, by weight, include: 5 parts of an inorganic pore-forming agent (D50 particle size of 0.01 μm) and 95 parts of PET material.

[0131] Example 6

[0132] Example 6 is basically the same as Example 1, the main difference being that the raw material components of the polyester substrate layer, by weight, include: 99 parts of PET material and 1 part of photo-strained material (barium titanate ceramic).

[0133] Example 7

[0134] Example 7 is basically the same as Example 1, the main difference being that the raw material components of the polyester substrate layer, by weight, include: 90 parts of PET material and 10 parts of photo-strained material (barium titanate ceramic).

[0135] Example 8

[0136] Example 8 is basically the same as Example 2, the main difference being that the wavelength of the irradiated light is 300nm.

[0137] Example 9

[0138] Example 9 is basically the same as Example 1, the main difference being that the raw material components of the first and second surface layers of Example 9 do not include an inorganic pore-forming agent.

[0139] Example 10

[0140] Example 10 is basically the same as Example 1, the main difference being that the light transmittance of the PET material, the first surface layer, and the second surface layer in Example 10 is 99%.

[0141] Example 11

[0142] Example 11 is basically the same as Example 1, the main difference being that the light transmittance of the PET material, the first surface layer, and the second surface layer in Example 10 is 92%.

[0143] Comparative Example 1

[0144] Polymer base layer: The polymer base layer is made of PET layer with a thickness of 6μm.

[0145] Composite current collector and its preparation method: Using 72 sets of evaporation boats and aluminum wires with a diameter of 2 mm, the aluminum wires are vacuum deposited on the opposite two sides of the polymer base layer to prepare the first metal layer and the second metal layer respectively. The thickness of the first metal layer and the second metal layer is 1 μm; thus, the composite current collector is obtained.

[0146] The process parameters for vacuum evaporation include: aluminum wire feeding speed of 450 mm / min, evaporation rate of 15 m / min, evaporation power of 8 kW, evaporation main roller temperature of -10℃, evaporation winding tension of 200 N, and distance between the evaporation boat and the polymer composite film in vacuum evaporation of 300 mm.

[0147] Comparative Example 2

[0148] Comparative Example 2 is basically the same as Example 1, except that the raw material composition of the polyester substrate in Comparative Example 2 does not include photo-strain material.

[0149] Performance testing:

[0150] Mechanical performance testing of composite current collectors

[0151] The tensile strength and elongation at break of the composite current collectors prepared in the examples and comparative examples were tested. The composite current collectors to be tested were cut into test strips using a strip cutting machine. Ten test strips were cut for each set of examples. The test strips were 15 mm wide and 150 mm long. The tensile rate was 100 mm / min and the spacing between the tensile clamps was 100 mm. The tensile strength and elongation at break in the MD direction were tested and the average value was taken. The test data are shown in Table 1.

[0152] Table 1

[0153]

[0154] Battery collision safety performance test

[0155] The ternary active material NCM811, conductive carbon black, and binder PVDF were thoroughly mixed in NMP at a weight ratio of 93:2:5 to obtain a positive electrode slurry. The positive electrode slurry was coated onto the current collector samples of the examples or comparative examples, dried, rolled, and then die-cut to obtain the positive electrode sheet.

[0156] The negative electrode active material, artificial graphite, binder SBR, dispersant CMC, and conductive carbon black were thoroughly mixed in water at a weight ratio of 95.5:2.3:1.5:0.7 to obtain a negative electrode slurry. The negative electrode slurry was coated onto copper foil, dried, rolled, and then die-cut to obtain the negative electrode sheet.

[0157] The positive electrode, separator (PE film), and negative electrode are stacked in sequence, wound to obtain a battery cell, placed in a battery casing, and electrolyte (lithium salt LiPF6, concentration 1mol / L, carbonate solvent) is added. After encapsulation, a battery sample is obtained.

[0158] The battery samples obtained from the composite current collectors prepared in the examples and comparative examples were subjected to collision safety performance tests.

[0159] (1) Battery pretreatment

[0160] The packaged battery sample is fully charged to its rated capacity (SOC=100%) and left to stand for at least 4 hours to eliminate polarization effects. A temperature measurement hole is pre-drilled during battery production to house a miniature thermocouple for temperature measurement.

[0161] (2) Battery fixing

[0162] The battery sample was fixed on the test bench using a three-point clamp, and a metal pendulum was mounted on the test bench, ensuring that the battery axis was completely perpendicular to the pendulum's trajectory. The impact center point was marked on the front of the battery.

[0163] (3) Collision test

[0164] Release the pendulum and let it fall freely to strike the center point of the front of the battery three times. Record the temperature inside the battery sample 10 minutes after the impact. The test data are shown in Table 2.

[0165] Table 2

[0166]

[0167] As can be seen from the test results in Tables 1 and 2, Examples 1 to 3 are basically the same. The main difference is that the types of photo-strain materials are different. Among them, the MIL-101 chromium metal-organic framework photo-strain material in Example 2 has the lowest cell temperature in the collision test. Therefore, it can more effectively suppress thermal runaway.

[0168] Example 1 and Example 4 are basically the same, the main difference being that the types of inorganic pore-forming agents are different. From the test results in Tables 1 and 2, it can be seen that the inorganic pore-forming agent calcium sulfate in Example 1 is easier to remove by acid washing, so as to enrich the porous structure of the first and second surface layers, thereby effectively suppressing battery thermal runaway and improving battery safety performance.

[0169] Examples 1 and 5 are basically the same, the main difference being the weight percentage of the inorganic pore-forming agent. Comparison revealed that in Example 1, when the weight percentages of the inorganic pore-forming agent and PET material were 20 parts and 80 parts respectively, the suppression effect on battery thermal runaway was excellent.

[0170] Examples 1, 6, and 7 are basically the same, with the main difference being the different weight fractions of the photo-strained material. Comparison revealed that in Example 7, when the weight fractions of PET material and photo-strained material were 90 parts and 10 parts respectively, the suppression effect on battery thermal runaway was excellent.

[0171] Examples 2 and 8 are essentially the same, with the main difference being the different wavelengths of the irradiated light. As can be seen from the above comparison, the irradiation parameters of the photo-strained material play a crucial role in reducing the elongation at break of the polyester composite film. The preferred irradiation wavelength for the MIL-101 chromium metal-organic framework is 340 nm to 365 nm.

[0172] Example 1 and Example 9 are basically the same, the main difference being that Example 9 does not contain a pore-forming agent. Since the first and second surface layers do not form a porous structure, their suppression of thermal runaway is relatively limited.

[0173] Examples 1, 10, and 11 are basically the same, with the main difference being that the light transmittance of the PET material, the first surface layer, and the second surface layer differs in each example. In Example 10, when the light transmittance of the PET material, the first surface layer, and the second surface layer is 99%, the photo-strained material can more significantly alter the stress distribution uniformity of the polyester substrate under light irradiation, thereby more effectively suppressing battery thermal runaway and ensuring battery safety performance.

[0174] Comparative Examples 1 and 2 did not use the polyester composite film of this application as the inner layer of the composite current collector, so their elongation at break and cell temperature were both high, and they could not suppress the thermal runaway phenomenon under impact conditions.

[0175] 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.

[0176] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A polyester composite film, characterized by, The polyester composite film comprises a polyester base layer and first and second surface layers respectively arranged on opposite sides of the polyester base layer. The polyester base layer comprises 90-99 parts by weight of a polyester material and 1-10 parts by weight of a photo-strain material. The first and second surface layers comprise a polyalkylene terephthalate polymer. The first and second surface layers and the polyester material each independently have a light transmittance of 92-99%. The first and second surface layers are porous structures.

2. The polyester composite film according to claim 1, characterized by, The first and second surface layers each independently comprise, by weight:

3. The polyester composite film according to claim 2, characterized by 5-30 parts of an inorganic porogen and 70-95 parts of a polyalkylene terephthalate polymer. The polyalkylene terephthalate polymer comprises one or more of polyethylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, and polyethylene terephthalate-1,4-cyclohexane dimethylene terephthalate.

4. The polyester composite film according to claim 3, characterized by The inorganic porogen comprises one or more of aluminum oxide, silicon dioxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, lead sulfate, and zinc oxide. The inorganic porogen has a D50 particle size of 0.01-2 μm. The polyester composite film has one or more of the following characteristics:

5. The polyester composite film according to any one of claims 1 to 4, characterized by, (1) The thickness ratio of the first surface layer to the polyester base layer is (1-1.5):(3-4). (2) The thickness ratio of the second surface layer to the polyester base layer is (1-1.5):(3-4). (3) The polyester material comprises one or more of polyethylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, and polyethylene terephthalate-1,4-cyclohexane dimethylene terephthalate. The polyester composite film comprises a polyester base layer and first and second surface layers respectively arranged on opposite sides of the polyester base layer, and the preparation method comprises the following steps:

6. A method for producing a polyester composite film, characterized by, The raw materials of the first, second, and third surface layers are independently mixed, and after melt-chip processing, first, second, and third chip materials are respectively prepared. The first, second, and third chip materials are independently melt-mixed, co-extruded, and then stretched to prepare a polyester composite film substrate. ​ The components of the polyester substrate layer include, in terms of weight fractions, 90-99 parts of a polyester material and 1-10 parts of a photo-strain material; the photo-strain material includes one or more of barium titanate ceramics, lead zirconate titanate ceramics, PI / CNTs photosensitive composite material, PEEK / anthraquinone photosensitive composite material, MIL-101 chromium metal organic framework, and UiO-66-NH2 / ZnO composite material; the components of the first surface layer and the second surface layer include polyalkylene terephthalate polymers; the light transmittances of the first surface layer, the second surface layer, and the polyester material are each independently 92%-99%; The polyester composite film substrate is subjected to light irradiation treatment to prepare a polyester composite film.

7. The method for preparing a polyester composite film according to claim 6, characterized by, The raw material components of the first surface layer and the second surface layer each independently include: 5-30 parts of an inorganic pore-forming agent and 70-95 parts of a polyalkylene terephthalate polymer; And / or, the preparation method includes, before the light irradiation treatment, subjecting the polyester composite film substrate to acid washing treatment to form a porous structure of the first surface layer and the second surface layer; And / or, the step of acid washing includes subjecting the polyester composite film substrate to acid washing treatment using an acid eluent; wherein the acid eluent includes one or more of hydrochloric acid, sulfuric acid, oxalic acid, citric acid, acetic acid, and hydrofluoric acid.

8. The method for producing a polyester composite film according to claim 6 or 7, characterized by, The process parameters of the light irradiation treatment include: irradiation light wavelength of 100-1000 nm, and irradiation time of 10 s-10 min.

9. The method for preparing a polyester composite film according to claim 8, characterized by, The light irradiation treatment has one or more of the following characteristics: (1) the photo-strain material is barium titanate ceramics, and the process parameters of the light irradiation treatment include: irradiation light type is ultraviolet light, and irradiation light wavelength is 240-260 nm; (2) the photo-strain material is lead zirconate titanate ceramics, and the process parameters of the light irradiation treatment include: irradiation light type is ultraviolet light, and irradiation light wavelength is 300-400 nm; (3) the photo-strain material is a PI / CNTs photosensitive composite material, and the process parameters of the light irradiation treatment include: irradiation light type is infrared light, and irradiation light wavelength is 800-1000 nm; (4) the photo-strain material is a PEEK / anthraquinone photosensitive composite material, and the process parameters of the light irradiation treatment include: irradiation light type is ultraviolet light, and irradiation light wavelength is 350-370 nm; (5) the photo-strain material is a MIL-101 chromium metal organic framework, and the process parameters of the light irradiation treatment include: irradiation light type is ultraviolet light, and irradiation light wavelength is 340-365 nm; (6) the photo-strain material is a UiO-66-NH2 / ZnO composite material, and the process parameters of the light irradiation treatment include: irradiation light type is ultraviolet light, and irradiation light wavelength is 300-400 nm.

10. A method of making a composite current collector, characterized by, The following steps are included: depositing a metal layer on at least one surface of the polyester composite film prepared by the preparation method of any one of claims 6-9, wherein the time interval between the light irradiation treatment and the deposition of the metal layer is 0.1 min-30 min.

11. A composite current collector, characterized by, The composite current collector comprises the polyester composite film according to any one of claims 1-5 and a metal layer arranged on at least one surface of the polyester composite film.

12. The composite current collector of claim 11, wherein, The material of the metal layer comprises one or more of aluminum and aluminum alloy. And / or, the thickness of the metal layer is 0.8-1.2 mm.

13. An electrode characterized by, The composite current collector according to claim 11 or 12 or prepared by the preparation method according to claim 10.

14. A battery, characterized by The electrode according to claim 13.

Images