Process method and system for controlling uniformity of large-size all-solid-state electrochromic device

Abstract

The invention discloses a process method and system for controlling the uniformity of a large-size all-solid-state electrochromic device, and the method comprises the steps: dividing the device into a plurality of independent temperature control regions, the device comprises a substrate, and a first transparent conductive layer, an ion storage layer, an ion conduction layer, an electrochromic layer and a second transparent conductive layer which are sequentially stacked on the surface of the substrate, applying a preset temperature gradient from the middle part to the marginal region of the device by adopting a matrix temperature control annealing process, so that the annealing temperature is gradually reduced from the middle region to the marginal region; through regional temperature regulation and control, the sheet resistance distribution of the first transparent conductive layer and the second transparent conductive layer meets the condition that the sheet resistance value of the edge region is higher than that of the middle region, and the sheet resistance difference rate of the edge region and the middle region is within 10%. The method for regulating and controlling the square resistance distribution of the transparent conducting layer through a matrix temperature control annealing process solves the problems of low color changing speed and non-uniform color caused by non-uniform annealing of a large-size electrochromic device.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromic processes, and particularly to a process method and system for controlling the uniformity of large-size all-solid-state electrochromic devices. Background Art

[0002] The structure of an all-solid-state electrochromic device is as Figure 1 shown, which is a sandwich structure composed of at least five functional film layers, where TCO-1 and TCO-2 are transparent conductive layers, EC is an electrochromic layer, IC is an ion conduction layer, and CE is an ion storage layer. When a voltage is applied between the two transparent conductive layers, the electrochromic device starts to color / fade.

[0003] However, as the size of the electrochromic device increases, the inherent resistance characteristics of the transparent conductive layer will cause uneven potential distribution, that is, a potential difference is formed between the bus bar end and the middle region in the large-size device due to resistance accumulation, resulting in a gradient phenomenon where the color change process gradually deepens from the bus bar end to the middle. This not only prolongs the overall color change time but also causes uneven color change.

[0004] It can be seen that optimizing the performance of the transparent conductive layer is the key to improving the efficiency of electrochromic devices. The transparent conductive layer is usually deposited on the substrate surface by magnetron sputtering, and then needs to be subjected to high-temperature air annealing treatment above 300 °C to improve its conductivity and light transmittance. The air annealing process usually uses radiation heating or assisted by convection, which makes the heat intensity of the edge region of the electrochromic device significantly higher than that of the middle part due to the superposition of thermal radiation or uneven convection, resulting in local differences in the sheet resistance of the transparent conductive layer. This annealing-induced uneven sheet resistance distribution further exacerbates the color gradient effect during the coloring / fading process of the device. Especially in the edge region, due to the too high conductivity, the color change depth is insufficient, forming a defect of "shallow edge coloring".

[0005] Currently, Chinese invention patent CN112981343A discloses a process method for controlling the coloring of large-size all-solid-state electrochromic devices, attempting to optimize the conductivity distribution by adjusting the oxygen partial pressure gradient of the transparent conductive layer. However, such methods only target the material preparation stage and fail to solve the problem of sheet resistance difference of the transparent conductive layer caused by uneven temperature distribution in the annealing process.

[0006] Therefore, how to achieve temperature uniformity control during the annealing process of large-size all-solid-state electrochromic glass, and then optimize the sheet resistance distribution of the transparent conductive layer, has become the core technical bottleneck for improving the color change speed and uniformity of all-solid-state electrochromic devices. Summary of the Invention

[0007] In the first aspect of the present invention, in order to solve the above technical problems, a process method for controlling the uniformity of a large-size all-solid-state electrochromic device is provided. The method includes: Dividing the device into multiple independently temperature-controlled regions. The device includes a substrate and a first transparent conductive layer, an ion storage layer, an ion conduction layer, an electrochromic layer, and a second transparent conductive layer that are sequentially stacked on the surface of the substrate; Adopting a matrix temperature-controlled annealing process to apply a preset temperature gradient to the central to edge regions of the device, so that the annealing temperature gradually decreases from the central region to the edge region; through sub-region temperature regulation, the sheet resistance distribution of the first transparent conductive layer and the second transparent conductive layer satisfies: the sheet resistance value in the edge region is higher than that in the central region, and the difference rate of the sheet resistance between the two is within 10%.

[0008] Further, the temperature gradient gradually decreases along the direction from the center to the edge of the device, and the decreasing amplitude is 5 - 50 °C.

[0009] Further, the annealing temperature range is 300 - 400 °C, wherein the temperature range of the central region is 350 - 380 °C, the temperature range of the edge region is 310 - 340 °C, and the temperature gradient difference between adjacent regions is 5 - 15 °C.

[0010] Further, the division method of the independently temperature-controlled regions is: Dividing the device into several columns along the length direction and several rows along the width direction to form a matrix partition, and the partition includes at least 4 quadrants.

[0011] Further, the temperature gradient is specifically configured as: Along the length direction, the temperature gradually decreases from the center to the two side edges; Along the width direction, the temperature gradually decreases from the center to the two side edges; The annealing temperature of the four corner regions is lower than the average temperature of the edge region.

[0012] Further, the method further includes: after the annealing is completed, performing a coloring / fading driving test on the device to verify the color change time and the color uniformity ΔE value.

[0013] Further, the color uniformity ΔE value is tested by sub-region. The device is divided into several grids, the color difference of the grids is measured, and the color uniformity ΔE value of all grids satisfies within 3.0.

[0014] In the second aspect of the present invention, an electrochromic device manufacturing system is provided, including: A magnetron sputtering device for depositing a transparent conductive layer on a substrate; A matrix temperature-controlled annealing device is used to implement the process method for controlling the uniformity of large-sized all-solid-state electrochromic devices on the coated devices; A voltage driving module is used to apply a coloring / fading driving voltage to the annealed device.

[0015] Furthermore, the matrix temperature-controlled annealing device includes a heating unit with independent temperature control for each region, which can achieve continuous adjustment of the temperature gradient from 380 °C to 310 °C.

[0016] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: The present invention controls the sheet resistance distribution of the transparent conductive layer by means of a matrix temperature-controlled annealing process method in which a preset temperature gradient is applied from the middle region to the edge region of the device, so that the annealing temperature gradually decreases from the middle region to the edge region, solving the problems of slow color change speed and uneven color caused by uneven temperature distribution in the annealing process of existing large-sized electrochromic devices. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the film layer structure of the electrochromic device disclosed in the embodiment of the present invention; Figure 2 It is a flowchart of the process method disclosed in the embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of the electrochromic device divided into four quadrants in the embodiment of the present invention; Figure 4 It is a relationship curve diagram of the sheet resistance and temperature of the transparent conductive layer in the electrochromic device disclosed in the embodiment of the present invention; Figure 5 It is a relationship curve diagram of the potential U between the transparent conductive layers and the position of the H side in the electrochromic device disclosed in the embodiment of the present invention; Figure 6 It is a relationship curve diagram of the actual potential difference ΔV and the position of the H side in the electrochromic device disclosed in the embodiment of the present invention; Figure 7 It is a temperature distribution diagram of the first quadrant on the surface of the original electrochromic device; Figure 8 It is a temperature setting diagram of the first quadrant on the surface of the adjusted electrochromic device disclosed in the embodiment of the present invention; Figure 9Gradient temperature setting diagram preset for the electrochromic device disclosed in the embodiments of the present invention; Figure 10 Coloring time comparison diagram of the electrochromic device; Figure 11 Fading time comparison diagram of the electrochromic device; Figure 12 ΔE value distribution diagram of the color uniformity of the original electrochromic device; Figure 13 ΔE value distribution diagram of the color uniformity of the electrochromic device disclosed in the embodiments of the present invention. Detailed implementation manners

[0019] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0020] The present invention aims to provide a process method for controlling the uniformity of a large-size all-solid-state electrochromic device, and solve the problems of slow color change speed and uneven color of the device caused by the difference in the sheet resistance of the transparent conductive layer due to uneven temperature distribution in the annealing process.

[0021] The core function of the all-solid-state electrochromic device depends on the synergistic effect of the multi-layer film structure. In this embodiment, the electrochromic device includes a substrate and a first transparent conductive layer, an ion storage layer, an ion conduction layer, an electrochromic layer, and a second transparent conductive layer that are sequentially stacked on the surface of the substrate. Hereinafter, for the convenience of description, the first transparent conductive layer and the second transparent conductive layer are collectively referred to as the transparent conductive layer in this embodiment.

[0022] Those skilled in the art further explain that the transparent conductive layer serves as an electrode to provide a charge transfer path; the electrochromic layer undergoes a redox reaction during ion insertion / extraction, resulting in a change in optical properties; the ion conduction layer allows ions to migrate between the electrochromic layer and the ion storage layer; the ion storage layer stores and releases ions to maintain charge balance. When a voltage is applied between the two transparent conductive layers, ions migrate from the ion storage layer through the ion conduction layer to the electrochromic layer, causing the electrochromic layer to be reduced and colored; the reverse voltage causes the ions to return to the ion storage layer, and the electrochromic layer is oxidized and faded.

[0023] Since, on the one hand, the sheet resistance of the transparent conductive layer causes a voltage drop during current transmission. In large-sized devices, the potential difference between the bus bar end (i.e., the edge region) and the central region is significant. Among them, the current density near the bus bar is high, the ion migration speed is fast, and the color change is relatively fast; the current density in the middle is low, the color change lags behind, and the coloring gradually deepens from the edge to the center, forming uneven color change. On the other hand, the traditional annealing process uses uniform heating (such as radiant heating). However, due to the superposition of thermal radiation or uneven convection, the edge is heated stronger, which results in better crystallinity and fewer defects in the edge region of the transparent conductive layer, and the sheet resistance is lower than that in the middle. Because the sheet resistance of the edge of the transparent conductive layer is low, that is, the potential difference is small, the driving force for ion migration is insufficient, and thus the problem of light coloring at the edge appears.

[0024] Please refer to Figure 2 , the present invention optimizes the problems of slow color change speed and uneven color of the device by annealing with a temperature gradient in sub-regions, and reversely regulating the sheet resistance distribution of the transparent conductive layer. The method mainly includes: S1. Divide the device into multiple independently temperature-controlled regions.

[0025] S2. Adopt a matrix temperature-controlled annealing process to apply a preset temperature gradient to the central to edge regions of the device, so that the annealing temperature gradually decreases from the central region to the edge region; through sub-region temperature control, make the sheet resistance distribution of the transparent conductive layer satisfy: the sheet resistance value of the edge region is higher than that of the central region, and the sheet resistance difference rate is within 10%.

[0026] The core principle of this matrix temperature-controlled annealing process is: The sheet resistance of the transparent conductive layer is closely related to the annealing temperature. It can be seen from Figure 4 that in the temperature range of t1 - t2, the film sheet resistance of the transparent conductive layer is negatively correlated with the temperature. Further, it is shown that high-temperature annealing can promote grain growth, reduce grain boundary scattering, and lower the sheet resistance; low-temperature annealing results in poor crystallinity, more grain boundaries and defects, and a higher sheet resistance. By adopting the annealing strategy of high temperature in the middle and low temperature at the edge, the sheet resistance of the central region is low due to the high annealing temperature; the sheet resistance of the edge region is high due to the low annealing temperature. It can be seen from Figure 5 that in the length direction, the voltage magnitude is negatively correlated with the distance of the measurement point from the bus bar. Due to the compensation effect of the potential difference, that is, under the driving voltage, the high sheet resistance at the edge increases the edge current density and thus compensates for the voltage drop from the bus bar to the middle. In this way, the current between the edge and the middle tends to be balanced, that is, the ion migration speed is the same, and thus the color change uniformity is improved. Also, because the overall potential distribution is more uniform, the driving efficiency is improved, and thus the coloring time is shortened.

[0027] The following specifically describes the matrix temperature-controlled annealing process disclosed in this embodiment.

[0028] Please refer to Figures 3 - 9, the device is equally divided into several columns along the length direction (i.e., the H side) and several rows along the width direction (i.e., the W side) to form a matrix partition. The bus bar is located on the W side, and the partition includes at least 4 quadrants. The temperature gradient gradually decreases from the center to the edge of the device, and the decreasing amplitude is 5 - 50 °C. The temperature gradient is specifically configured as follows: along the length direction, the temperature decreases from the center to the two side edges in sequence, and each column decreases by 5 - 15 °C; along the width direction, the temperature decreases from the center to the two side edges in sequence, and each row decreases by 5 - 10 °C; the annealing temperature in the four corner regions is lower than the average temperature in the edge region to further suppress the sheet resistance at the edge.

[0029] In this embodiment, the annealing temperature range is 300 - 400 °C. Among them, the temperature range in the central region is 350 - 380 °C, the temperature range in the edge region is 310 - 340 °C, and the temperature gradient difference between adjacent regions is 5 - 15 °C.

[0030] Please refer to Figures 10 - 13 , after the annealing is completed, the device is subjected to a coloring / fading driving test to verify the color change time and the color uniformity ΔE value. The color uniformity ΔE value is tested by dividing the region. The device is divided into several grids, the color difference of the grids is measured, and the color uniformity ΔE value of all grids satisfies within 3.0.

[0031] First, large-sized inorganic all-solid-state electrochromic devices prepared in the same batch are annealed according to the original annealing scheme and the annealing scheme provided by the present invention respectively, and then their coloring / fading times are measured respectively. Specifically, 16 pieces of inorganic all-solid-state electrochromic glass with a size of 1500 * 1000 mm are divided into two groups. Among them, 8 pieces are heat-treated by the existing annealing method, and the other 8 pieces are heat-treated by this annealing scheme. Taking the first quadrant part as an example, the specific implementation temperatures are as follows in the table: (unit: °C)

[0032] All glasses are driven to color and fade with a voltage of 3V, and their coloring and fading times are recorded. It can be seen from Figures 10 - 11 that compared with the original annealing scheme, the coloring / fading time in the scheme provided by this embodiment is significantly reduced.

[0033] Then, the large-sized inorganic all-solid-state electrochromic glass is evenly divided into 5 * 5 grid regions. As shown in the following table, the color uniformity ΔE values of each of the 25 regions of each piece are measured respectively. It is equally divided into five columns along the W side direction (each 300 mm is a column, distributed as columns A, B, C, D, and E), and the ΔE values of each column are obtained:

[0034] It can be seen from Figures 12 - 13 that compared with the original annealing scheme, the color uniformity in the scheme provided by this embodiment is significantly improved.

[0035] The present invention also protects a preparation system for an electrochromic device, which mainly includes a magnetron sputtering device, a matrix temperature-controlled annealing device, and a voltage driving module. Among them, the magnetron sputtering device is used to deposit a transparent conductive layer on a substrate; the matrix temperature-controlled annealing device is used to implement the above process method for controlling the uniformity of a large-size all-solid-state electrochromic device on the coated device; the voltage driving module is used to apply a coloring / fading driving voltage to the annealed device.

[0036] Among them, the matrix temperature-controlled annealing device includes a heating unit with independent temperature control in different regions, which can realize continuous adjustment of the temperature gradient from 380 °C to 310 °C.

[0037] In this embodiment, the matrix temperature-controlled annealing device is composed of an infrared heating plate, a thermocouple / infrared thermometer, and a PID controller, and each partition is independently feedback-regulated.

[0038] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process method for controlling the uniformity of a large-size all-solid-state electrochromic device, characterized in that The method includes: Dividing the device into multiple independently temperature-controlled regions, where the device includes a substrate and a first transparent conductive layer, an ion storage layer, an ion conduction layer, an electrochromic layer, and a second transparent conductive layer sequentially stacked on the surface of the substrate; Adopting a matrix temperature-controlled annealing process to apply a preset temperature gradient to the middle to edge region of the device, so that the annealing temperature gradually decreases from the middle region to the edge region; through sub-region temperature regulation, the sheet resistance distribution of the first transparent conductive layer and the second transparent conductive layer satisfies that the sheet resistance value in the edge region is higher than that in the middle region and the sheet resistance difference rate is within 10%.

2. The process method for controlling the uniformity of a large-sized all-solid-state electrochromic device according to claim 1, characterized in that, The temperature gradient gradually decreases along the direction from the center to the edge of the device, and the decreasing amplitude is 5 - 50 °C.

3. The process method for controlling the uniformity of a large-size all-solid-state electrochromic device according to claim 1, characterized in that, The annealing temperature range is 300 - 400 °C, where the temperature range of the middle region is 350 - 380 °C, the temperature range of the edge region is 310 - 340 °C, and the temperature gradient difference between adjacent regions is 5 - 15 °C.

4. The process method for controlling the uniformity of a large-size all-solid-state electrochromic device according to claim 1, wherein The division method of the independently temperature-controlled regions is: Dividing the device into several columns along the length direction and several rows along the width direction to form a matrix partition, and the partition includes at least 4 quadrants.

5. The process method for controlling the uniformity of a large-sized all-solid-state electrochromic device according to claim 4, characterized in that, The temperature gradient is specifically configured as: Along the length direction, the temperature gradually decreases from the center to the two side edges; Along the width direction, the temperature gradually decreases from the center to the two side edges; The annealing temperature of the four corner regions is lower than the average temperature of the edge region.

6. The process method for controlling the uniformity of a large-size all-solid-state electrochromic device according to claim 1, characterized in that, The method further includes: after annealing is completed, performing a coloring / fading driving test on the device to verify the color change time and the color uniformity ΔE value.

7. The process method for controlling the uniformity of a large-size all-solid-state electrochromic device according to claim 6, characterized in that, The color uniformity ΔE value is tested by sub-region. The device is divided into several grids, the color difference of the grids is measured, and the color uniformity ΔE value of all grids satisfies within 3.

0.

8. An electrochromic device manufacturing system, characterized in that, It includes: A magnetron sputtering device for depositing a transparent conductive layer on the substrate; A matrix temperature-controlled annealing device for implementing the process method for controlling the uniformity of a large-size all-solid-state electrochromic device according to any one of claims 1 to 7 on the coated device; A voltage driving module for applying a coloring / fading driving voltage to the annealed device.

9. The electrochromic device manufacturing system according to claim 8, wherein The matrix temperature-controlled annealing device includes a heating unit with independently controlled temperature for each region, and can realize continuous adjustment of the temperature gradient from 380 °C to 310 °C.

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