Method for determining electrode lead-out position of electrochromic device, and electrochromic device

Abstract

The present application is applicable to the field of electrochromic technology, and provides a method for determining an electrode lead-out position of an electrochromic device, and an electrochromic device. The method comprises: acquiring an electric field intensity at a target point in an electrochromic device during the process of charging or discharging the electrochromic device according to a preset condition; on the basis of the rate of change of the electric field intensity, changing the relative position of the connection between a power supply and the electrochromic device; re-acquiring an electric field intensity at a target point in the electrochromic device during the process of charging or discharging the electrochromic device according to the preset condition; and when the rate of change of the electric field intensity at all target points is lower than a preset threshold, determining a current position at which the power supply and the electrochromic device are connected as an electrode lead-out position. Therefore, the electric field intensity distribution of the electrochromic device is more uniform, thereby avoiding failure caused by excessively high electric field intensity in some regions of the electrochromic device, and improving the cyclic performance.

Description

Method for determining electrode lead-out position of electrochromic device and electrochromic device

[0001] The present application claims priority to the Chinese patent application No. 202410737471.4, filed on June 6, 2024 in the China Patent Office and entitled "Method for determining electrode lead-out position of electrochromic device and electrochromic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of electrochromic technology, more particularly, to a method for determining electrode lead-out position of electrochromic device and electrochromic device. BACKGROUND

[0003] An electrochromic device is a device that can change color under the action of voltage. The core of the electrochromic device is electrochromic material. Electrochromic materials change their light absorption properties when a voltage is applied or removed, thereby changing color. The transmittance of the electrochromic device changes with the voltage applied between the first conductive layer and the second conductive layer. Therefore, when different voltages are applied, the electrochromic device will display different transmittance states.

[0004] At present, during use of the electrochromic device, some areas of the electrochromic device are prone to premature failure, which eventually leads to rapid failure of the entire electrochromic device.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. TECHNICAL PROBLEM

[0006] The purpose of the embodiments of the present application is to provide a method for determining electrode lead-out position of electrochromic device and electrochromic device, aiming to solve the technical problem that the corner area of the electrochromic device is prone to premature failure in the prior art. TECHNICAL SOLUTION

[0007] To achieve the above purpose, the technical solution adopted by the present application is to provide a method for determining electrode lead-out position of electrochromic device, comprising:

[0008] obtaining the electric field intensity of a target point in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition;

[0009] changing the relative position of the electrochromic device and the power supply according to the change rate of the electric field intensity;

[0010] Obtaining the electric field intensity of the target point in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition;

[0011] When the change rate of the electric field intensity of the target point is lower than a preset threshold, the position where the current power supply is connected to the electrochromic device is determined as the electrode leading-out position.

[0012] In a possible design, the obtaining the electric field intensity of the target point in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition comprises:

[0013] Obtaining the transmittance of the target point or the potential difference of the target point during charging or discharging of the electrochromic device;

[0014] Determining the change rate of the electric field intensity according to the change rate of the transmittance or the potential difference.

[0015] In a possible design, the determining the change rate of the electric field intensity according to the change rate of the transmittance or the potential difference comprises:

[0016] Obtaining the transmittance of the target point during charging or discharging of the electrochromic device;

[0017] Obtaining a transmittance change curve of the transmittance of the target point changing over time, and determining a first slope of the transmittance change curve;

[0018] Determining the change rate of the electric field intensity of the target point according to the first slope, wherein the value of the first slope is positively correlated with the change rate of the electric field intensity of the target point.

[0019] In a possible design, when the absolute value of the first slope is less than a slope threshold, it is determined that the change rate of the electric field intensity of the target point is lower than a preset threshold, wherein the threshold of the absolute value of the slope is greater than 0 and less than 10.

[0020] In a possible design, the determining the change rate of the electric field intensity according to the change rate of the transmittance or the potential difference comprises:

[0021] Measuring the potential difference of the target point during charging or discharging of the electrochromic device;

[0022] When the potential difference of the target point rises to a first preset voltage or falls to a second preset voltage, a current time point is determined as a first time point;

[0023] Calculating a duration between the first time point and an end time point when the charging or discharging of the electrochromic device is completed;

[0024] Determining the change rate of the electric field intensity according to the duration, wherein the duration is positively correlated with the change rate of the electric field intensity of the target point.

[0025] In a possible design, the method further includes:

[0026] When the duration is less than the time threshold, it is determined that the rate of change of the electric field intensity of the target point is lower than the preset threshold, where the time threshold is less than 50s.

[0027] In a possible design, the target point is a point in a corner region of the electrochromic device.

[0028] In a possible design, the preset condition is full charging of the electrochromic device according to a first preset voltage, and / or full discharging of the electrochromic device according to a second preset voltage.

[0029] In a possible design, the relative position of the power supply and the electrochromic device is changed according to the rate of change of the electric field intensity, including: changing the position of the power supply connected to the electrochromic device along a preset path, where the preset path is along an edge of the electrochromic device, away from a corner region corresponding to the target point with a larger rate of change of the electric field intensity, or close to a corner region corresponding to the target point with a smaller rate of change of the electric field intensity.

[0030] Another aspect of the present application provides an electrochromic device, and the electrode lead-out position of the electrochromic device is determined by the method. Advantages

[0031] The method for determining the electrode lead-out position of the electrochromic device provided by the present application mainly has the following advantages: the electrode lead-out position of the electrochromic device is determined by determining target points on the electrochromic device, obtaining the electric field intensity of the target points in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition, changing the relative position of the power supply and the electrochromic device according to the rate of change of the electric field intensity based on the obtained results, obtaining the electric field intensity of the target points in the electrochromic device again during charging or discharging of the electrochromic device according to the preset condition, and determining the current position of the power supply connected to the electrochromic device as the electrode lead-out position when the rate of change of the electric field intensity of the target points is lower than a preset threshold or the difference between the rates of change of the electric field intensity of the target points is within a preset range. Therefore, the electric field intensity distribution of the electrochromic device is more uniform after the circuit board is connected to the electrochromic device at the current position, and the local area of the electrochromic device does not appear to have a high electric field intensity, thereby avoiding the failure of the local area of the electrochromic device and improving the cycle performance of the electrochromic device. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor.

[0033] Fig. 1 is a sectional view of an electrochromic device according to an embodiment of the present application;

[0034] Fig. 2 is a structural schematic diagram of an electrochromic device according to an embodiment of the present application;

[0035] Fig. 3 is a schematic diagram of each corner of an electrochromic device according to an embodiment of the present application;

[0036] Fig. 4 is a graph of the change of transmittance of point a of an electrochromic device according to an embodiment of the present application over time;

[0037] Fig. 5 is a schematic diagram of a straight line corresponding to the first slope of the change curve of transmittance of point a of an electrochromic device according to an embodiment of the present application over time;

[0038] Fig. 6 is a graph of the change of potential difference of point a of an electrochromic device according to an embodiment of the present application over time;

[0039] Fig. 7 is a schematic diagram of a first region and a second region;

[0040] Fig. 8 is a structural schematic diagram of a structure with a slot along the boundary line of the first region and the second region;

[0041] Fig. 9 is a schematic diagram of a target point;

[0042] Fig. 10 is another schematic diagram of a target point.

[0043] Main figure mark explanation:

[0044] 1-first substrate layer, 2-first conductive layer, 3-electrochromic layer, 4-second conductive layer, 5-second substrate layer, 6-first electrode, 7-second electrode, 8-first circuit board, 9-second circuit board, 11-first groove, 12-second groove. Embodiment of the present application

[0045] In order to make the technical problems, technical solutions and beneficial effects of the present application more clearly understood, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0046] It is to be noted that when an element is referred to as being "fixed" or "set" on another element, it can be directly on the other element or indirectly on the other element with intervening elements. When an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or indirectly connected or coupled to the other element through intervening elements.

[0047] It is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, specify relative positions and orientations based on the orientations or positions shown in the drawings, and are used only for the purpose of convenience and simplicity of description and illustration, and thus are not intended to indicate or imply that a device or element referred to in such a manner must have a particular orientation, be constructed and operated in a particular orientation, and thus cannot be interpreted as a limitation thereon.

[0048] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or a quantity of the indicated features. Thus, a feature defined with "first", "second", etc. can include one or more of the features implicitly or explicitly. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0049] Referring to FIG. 1 and FIG. 2, the structure of the electrochromic device is first described. The electrochromic device includes a first substrate layer 1, a first conductive layer 2, an electrochromic layer 3, a second conductive layer 4, and a second substrate layer 5, which are sequentially stacked. The first substrate layer 1 and the second substrate layer 5 are both transparent flexible materials such as PET (Polyethylene terephthalate) or PC. The first conductive layer 2 and the second conductive layer 4 are both transparent ITO (Indium Tin Oxide) materials. The electrochromic layer 3 includes an electrochromic material layer, an electrolyte layer, and an ion conduction layer, which are sequentially stacked. In other embodiments, the electrochromic layer 3 can also be a liquid crystal or the like.

[0050] A plurality of first grooves 11 are arranged at intervals in the edge portion of the electrochromic film, the first grooves 11 penetrating the second conductive layer and the electrochromic layer to expose the first conductive layer 2 to form the first electrode 6. A plurality of second grooves 12 are arranged at intervals in the other side of the opening of the first grooves, the second grooves 12 penetrating the first conductive layer and the electrochromic layer to expose the second conductive layer 4 to form the second electrode 7. A first bus bar (not shown in the figure) is arranged on one side of the electrochromic film in the thickness direction, extending along the circumference of the electrochromic device and electrically connected to each first electrode strip. A second bus bar is arranged on the other side of the electrochromic film in the thickness direction, extending along the circumference of the electrochromic device and electrically connected to each second electrode. In order to facilitate electrical connection with an external power supply, a lead-out structure is usually provided to connect with the bus bar. It is worth noting that the cutting line for cutting the electrode from the back surface is represented by a dashed line in the figure.

[0051] By way of example, the lead-out structure is a flexible circuit board, one end of the first circuit board 8 is connected to the first bus bar (not shown in the figure), i.e., electrically connected to each first electrode, and the other end extends outward from the film to be connected to the positive or negative pole of the power supply. One end of the second circuit board 9 is connected to the second bus bar, i.e., electrically connected to each second electrode, and the other end extends to be connected to the negative or positive pole of the power supply. The first circuit board 8 and the second circuit board 9 are flexible circuit boards, silver wire leads, etc. When the first circuit board 8 and the second circuit board 9 are connected to an external power supply and current is passed through the first conductive layer 2 and the second conductive layer 4, an electric field is formed between the first conductive layer 2 and the second conductive layer 4, causing the electrochromic layer 3 to undergo stable and reversible color changes under the action of the electric field.

[0052] The inventor found that due to the diffusion and superposition of the electric field of the first electrode 6 and the second electrode 7, the electric field intensity at the corner position of the electrochromic device is relatively large. Moreover, the field intensity at the position close to the lead-out structure is also larger than that at other positions. When the lead-out structure is close to a certain corner position, the electric field intensity at the corner position adjacent to the lead-out structure will be significantly increased, causing the corresponding corner position to be continuously subjected to high voltage during the color changing process, resulting in overcharging or overdischarging and failure, partial area failure, and ultimately accelerating the failure speed of the entire electrochromic device.

[0053] For irregular electrochromic films or electrochromic devices with uneven internal resistance, it is difficult to determine the position of the lead-out structure, causing the partial corner area or the position with smaller internal resistance of the electrochromic device to be easily overcharged or overdischarged during the charging and discharging process, and thus fail.

[0054] To solve the above problems, embodiments of the present application provide a method for determining the electrode lead-out position of an electrochromic device, which can be mainly applied to the determination of the electrode lead-out position of an electrochromic device in the field of intelligent light modulation such as glass curtain wall, automobile side window, sunroof, sun visor, rearview mirror, electronic device shell, etc. The method for determining the electrode lead-out position of an electrochromic device is conducive to making the electric field intensity of each position of the electrochromic device more uniform, so as to improve the cycle performance of the corresponding electrochromic device.

[0055] The following will be described in detail in combination with specific drawings and embodiments.

[0056] Referring to FIGS. 1-10, some embodiments of the present application provide a method for determining the electrode lead-out position of an electrochromic device. It should be noted that the electrode lead-out position refers to the relative position on the electrochromic device that is in direct contact with the lead-out structure, that is, the position where the current of the power supply enters the electrochromic film. The method can determine the lead-out position of an electrochromic device with the same shape or similar shape as the electrochromic device sample through the electrochromic device sample. The method comprises: obtaining the electric field intensity of a target point in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition; changing the relative position of the power supply connected to the electrochromic device according to the change rate of the electric field intensity; obtaining the electric field intensity of the target point in the electrochromic device again during charging or discharging of the electrochromic device according to the preset condition; and determining the current position of the power supply connected to the electrochromic device as the electrode lead-out position when the change rate of the electric field intensity of all target points is lower than a preset threshold.

[0057] In some embodiments, the target point is a position in the electrochromic device that is prone to failure, which can be determined by accelerated aging test of the electrochromic device sample. Generally, the target point is a point in the corner region of the electrochromic device. The corner region is the region corresponding to at least one electrode, that is, one groove, in each of the two adjacent straight edges of the electrochromic device. For convenience of description, the electrochromic device in the following embodiments is taken as an example of a rectangular electrochromic film. Referring to FIG. 3, the electrochromic film is rectangular, and the electrochromic film has four corners, which are the four interior angles of the rectangle, respectively, which are the first corner, the second corner, the third corner and the fourth corner. Among them, the region corresponding to the first corner is the A region in FIG. 3, the region corresponding to the second corner is the B region in FIG. 3, the region corresponding to the third corner is the C region in FIG. 3, and the region corresponding to the fourth corner is the D region in FIG. 3. Of course, for the convenience of understanding, the A region, the B region, the C region and the D region in the figure are divided by dashed lines respectively, and in fact, the boundaries of the A region, the B region, the C region and the D region are not limited by the positions of the dashed lines in the figure.

[0058] Referring to FIG. 3, at least one target point can be selected at each corner of the electrochromic device, and the electric field strength of the target point is taken as the electric field strength of the corresponding corner. For example, a point a is selected in the A region, a point b is selected in the B region, a point c is selected in the C region, and a point d is selected in the D region. The electric field strength of the point a is taken as the electric field strength of the first corner, the electric field strength of the point b is taken as the electric field strength of the second corner, the electric field strength of the point c is taken as the electric field strength of the third corner, and the electric field strength of the point d is taken as the electric field strength of the fourth corner. In some embodiments, the point a can be the center position of the first corner, the point b can be the center position of the second corner, the point c can be the center position of the third corner, and the point d can be the center position of the fourth corner. In other embodiments, at least two alternative points are selected in each corner of the electrochromic device, for example, three target points are selected in each corner of the electrochromic device, the electric field strengths of the three target points are measured, and the highest value of the electric field strength change rates of the three target points is taken as the electric field strength change rate of the corner where the target point is located. Thus, the probability of a large electric field strength at the corner can be reduced by introducing a structure position.

[0059] In some preferred embodiments, when the electric field strength change rates of all the target points are lower than the preset threshold, the position where the current power supply is connected to the electrochromic device is determined as the electrode lead-out position. In some preferred embodiments, when the number of target points whose electric field strength change rates are lower than the preset threshold accounts for more than half of the total number, the position where the current power supply is connected to the electrochromic device is determined as the electrode lead-out position. Since the electrochromic device is usually irregular in shape, the speed of partial failure can be reduced and the service life of the device can be improved when the position of the lead-out structure is adjusted as long as part of the requirements are met.

[0060] Preferably, when the electric field strength change rates of all the target points are lower than the preset threshold, the position where the current power supply is connected to the electrochromic device is determined as the electrode lead-out position.

[0061] In some embodiments, after the target points are determined, the electrochromic device is connected to a battery cycle test cabinet, and the electrochromic device is charged according to a preset condition, and the preset condition is that the electrochromic device is fully charged according to a first preset voltage. In other embodiments, the electrochromic device is discharged according to a preset condition, and the preset condition is that the electrochromic device is fully discharged according to a second preset voltage. In yet other embodiments, the electrochromic device is fully charged according to the first preset voltage and fully discharged according to the second preset voltage, so that the transmittance of the electrochromic device changes periodically. Full charging is charging the electrochromic device from its lowest open circuit voltage to the highest open circuit voltage of the electrochromic device at a positive voltage, which is generally from the darkest state to the brightest state. Reaching the highest open circuit voltage generally uses current as the cutoff condition, and the charging current is measured after 5 seconds of charging, and when the charging current is less than 40 mA, it is considered to be fully charged. Full discharge is discharging the electrochromic device from its highest open circuit voltage to the lowest open circuit voltage of the electrochromic device at a negative voltage. It is generally discharged from the brightest state to the darkest state. Reaching the lowest open circuit voltage generally uses current as the cutoff condition, and the discharge current is measured after 5 seconds of charging, and when the absolute value of the discharge current is less than 40 mA, it is considered to be fully discharged. A stable change period is selected, and the electric field strength of the target points at multiple time points in the change period is measured. For example, an electric field strength tester is used, and the electric field strength of the target points is measured every 5 seconds. According to the measurement results, the change rate of the electric field strength of each target point is calculated, and the first target point with the maximum electric field strength change rate and the second target point with the minimum electric field strength change rate are determined. In some embodiments, the power supply is connected to the electrochromic device through a circuit board, which can be a flexible circuit board (FPC) or other circuit board. By moving the circuit board along the circumference of the electrochromic device, in other words, moving the circuit board along the direction in which the bus bar extends, the relative position of the circuit board and the electrochromic device is changed, so that the circuit board is away from the corner corresponding to the first target point with a stronger electric field strength or the circuit board is close to the corner corresponding to the second target point with a weaker electric field strength. Every time the position where the power supply is connected to the electrochromic device is moved by one unit, for example, every 5 cm, the electric field strength of the target points is measured every 5 seconds. According to the measurement results, the change rate of the electric field strength of each target point is calculated, and when the change rate of the electric field strength of all target points is lower than a preset threshold, the current position of the circuit board is determined as the electrode lead-out position of the electrochromic device. It is worth noting that the circuit board can be moved in the length direction of one electrode, or it can be moved to another electrode, so as to change the relative position of the electrochromic device and the circuit board.

[0062] It should be noted that the preset threshold value is related to the material of the electrochromic device and the area of the electrochromic device, of course, also related to the applied voltage. The preset threshold value corresponding to the electrochromic device can be 0.1v / s, 0.2v / s, 0.3v / s, 0.4v / s, etc. For example, in some embodiments, the preset threshold value corresponding to the electrochromic device is 0.2v / s, and when the rate of change of the electric field intensity of all target points is lower than 0.2v / s, the current position of the circuit board is determined as the electrode lead-out position of the electrochromic device.

[0063] In some embodiments, after determining the target point with the maximum rate of change of electric field intensity as the first target point and the target point with the minimum rate of change of electric field intensity as the second target point, the electrical connection between the disconnected electrochromic device and the power supply is disconnected, the circuit board is moved along the edge of the electrochromic device, and then the power supply and the electrochromic device are connected again, so that the position where the power supply and the electrochromic device are connected is away from the corner corresponding to the first target point or the circuit board is close to the corner corresponding to the second target point. For example, referring to FIG. 3, the rate of change of electric field intensity of point a is the maximum, the rate of change of electric field intensity of point b is the minimum, and the initial position of the circuit board is between the first corner A and the second corner B. The circuit board is moved from the initial position along the edge of the electrochromic device away from the first corner A or towards the second corner B, and then the power supply and the electrochromic device are connected again. During the movement, the rate of change of electric field intensity of each target point is measured once for each position of the circuit board, until the rate of change of electric field intensity of all target points is lower than the preset threshold value, and then the current position of the circuit board is determined as the electrode lead-out position of the electrochromic device. For another example, the rate of change of electric field intensity of point a is the maximum, the rate of change of electric field intensity of point c is the minimum, and the initial position of the circuit board is between the first corner and the second corner. The circuit board is moved from the initial position along the edge of the electrochromic device, away from the first corner or towards the third corner, and during the movement, the rate of change of electric field intensity of each target point is measured once for each position of the circuit board, until the rate of change of electric field intensity of all target points is lower than the preset threshold value, and then the current position of the circuit board is determined as the electrode lead-out position of the electrochromic device.

[0064] For example, the circuit board is connected to the power supply and the electrochromic device on the electrochromic device sample, and the position where the circuit board is connected to the electrochromic device is the position where the power supply is connected to the electrochromic device. The method for moving the position where the power supply is connected to the electrochromic device can be directly changing the relative position of the circuit board connected to the electrochromic device. In other embodiments, multiple circuit boards are arranged on the electrochromic device, and a selection switch is arranged between the circuit boards and the power supply. The power supply is connected to one of the circuit boards through the controller to change the position where the power supply is electrically connected to the electrochromic device.

[0065] It should be noted that, generally, under the premise that the lengths of the electrodes on both sides of the corner are consistent, the smaller the angle of the corner, the greater the electric field strength after the superposition of the electric fields generated by the electrodes on both sides of the corner, that is, the electric field strength of the acute corner is greater than that of the right angle corner, which is greater than that of the obtuse corner. In some embodiments, the initial position of the electrode lead-out position of the electrochromic device can be selected near the corner with a larger angle, the circuit board is connected to the electrochromic device at this position, and the external power supply is connected to the electrochromic device to measure the electric field strength, which can avoid large differences in the electric field strength change rate data of each corner of the electrochromic device, and is beneficial to faster moving the circuit board to a position where the electric field strength change rate of all corners is below the preset threshold, so as to find the electrode lead-out position of the electrochromic device faster.

[0066] By using the technical solutions provided in some embodiments of the present application, the target point positions are determined at each corner of the electrochromic device, the electric field strength of each target point position is measured, the electric field strength change rate of each target point position is calculated, the change rate of the electric field strength is used to represent whether the color change of each target point position is balanced during the full charging and / or full discharging process of the electrochromic device, the relative position of the power supply and the electrochromic device is changed based on the change rate of the electric field strength, and when the electric field strength change rate of all target point positions is below the preset threshold or the difference between the electric field strength change rates of each target point position is within the preset range, the current position of the power supply connected to the electrochromic device is determined as the electrode lead-out position. Thus, after the circuit board is connected to the electrochromic device at the current position, the overall electric field strength distribution of the electrochromic device is more uniform, and local corner regions do not have excessively high electric field strength, thereby avoiding the failure of local corner regions of the electrochromic device, and further improving the cycle performance of the electrochromic device. The electric field change rate below the preset threshold indicates that the color change speed of each corner region is below the threshold, that is, it will not cause premature failure of each region, and plays a role in delaying the failure of the electrochromic device.

[0067] In some embodiments of the present application, the electric field intensity of the target point of the electrochromic device during charging or discharging of the electrochromic device according to the preset condition is obtained, including: obtaining the transmittance of the target point or the potential difference of the target point during charging or discharging of the electrochromic device. For example, the transmittance of each target point is tested by a transmittance tester, and a transmittance change over time is made, or the potential difference of each target point of the electrochromic device is tested according to a voltmeter. The change rate of the electric field intensity is determined according to the change rate of the transmittance of the target point or the potential difference of the target point. Since the change of the electric field intensity can be directly reflected in the change of the transmittance, the change rate of the electric field intensity can be more conveniently reflected by testing the change of the transmittance. In addition, since the voltage difference and the potential difference are positively correlated, the change rate of the electric field intensity of each point can also be directly obtained by testing the potential difference. Compared with directly measuring the electric field intensity by using an electric field intensity tester, the measurement data is relatively more stable and accurate by measuring the transmittance of the target point or the potential difference of the target point to determine the electric field intensity of the target point.

[0068] In some embodiments of the present application, the change rate of the electric field intensity is determined according to the change rate of the transmittance of the target point or the potential difference of the target point, including: obtaining the transmittance of the target point during charging or discharging of the electrochromic device; obtaining a transmittance change curve of the transmittance of the target point over time, determining a first slope of the transmittance change curve; and determining the change rate of the electric field intensity of the target point according to the first slope, wherein the value of the first slope is positively correlated with the change rate of the electric field intensity of the target point.

[0069] In some embodiments, the electrochromic device is connected to a battery cycle test cabinet, which is a cycle device with pre-stored test logic. Different cycle parameters are set according to different materials of the electrochromic device, such as charging voltage or discharging voltage, charging or discharging cutoff conditions, etc. The electrochromic device is fully charged according to a first preset voltage. In some other embodiments, the electrochromic device is fully discharged according to a second preset voltage. In some other embodiments, the electrochromic device is fully charged according to the first preset voltage and fully discharged according to the second preset voltage, so that the transmittance of the electrochromic device changes periodically. A stable change period is selected, in which the transmittance of the electrochromic device changes from low to high or from high to low. The transmittance of the target point in a change period is measured, a transmittance change curve of the transmittance of the target point over time is obtained, a first slope K of the transmittance change curve is determined, and the change rate of the electric field intensity of the target point is determined according to the first slope K. The value of the first slope K is positively correlated with the change rate of the electric field intensity of the target point.

[0070] In some embodiments, the transmittance meter is placed at the target points corresponding to the first corner, the second corner, the third corner and the fourth corner, respectively, i.e., points a, b, c and d, the electrochromic device is connected to the battery cycle test cabinet, and the transmittance of the electrochromic device is periodically changed according to the cycle logic of the product corresponding to the electrochromic device. In order to ensure the stability of the data, the transmittance corresponding to points a, b, c and d is recorded from the second cycle. The transmittance change curve of the transmittance corresponding to each target point with respect to time is drawn.

[0071] Referring to FIG. 4, taking point a as an example, FIG. 4 is a transmittance change curve of the transmittance of point a with respect to time, the horizontal axis in the figure represents time, and the vertical axis represents the transmittance of point a. It can be seen that after applying a forward voltage to the electrochromic device, the transmittance of point a gradually increases, and after increasing to a certain extent, the transmittance of point a is basically maintained unchanged, then a reverse voltage is applied to the electrochromic device, and the transmittance of point a gradually decreases, i.e., the cycle process of the electrochromic device from dark to light and then to dark is shown in FIG. 4. The rising section of the transmittance of the electrochromic device from low to high is taken, for the convenience of understanding, the rising section is the curve section between the two dashed lines in the figure. Then the first slope K of the rising section is obtained, the electric field strength of the target point is determined according to the first slope K, and the value of the first slope K is positively correlated with the electric field strength of point a.

[0072] It should be noted that the greater the change rate of the electric field strength, the faster the color change speed of the electrochromic device, and the longer the electrochromic device is subjected to continuous high voltage, which will result in a greater probability of failure of the electrochromic device. The value of the first slope K reflects the color change speed of the electrochromic device, i.e., the greater the value of the first slope K, the faster the color change of the electrochromic device. Therefore, the value of the first slope K is positively correlated with the change rate of the electric field strength.

[0073] Referring to FIG. 5, in some embodiments of the present application, determining the first slope of the transmittance change curve includes: determining the lowest point and the highest point on the transmittance change curve, and connecting the first point and the second point between the lowest point and the highest point to form a line, and the slope of the line corresponds to K. Wherein the transmittance of the first point is 10% higher than that of the lowest point, and the transmittance of the second point is 10% lower than that of the highest point. Alternatively, the starting point and the ending point of the transmittance change curve can be determined, the starting point is the coordinate point with the lowest transmittance on the transmittance change curve, and the ending point is the coordinate point with the highest transmittance on the transmittance change curve; the transmittance change curve between the starting point and the ending point is determined as the target curve, that is, the transmittance change curve of the electrochromic device from the lowest transmittance charging to the highest transmittance. The transmittance corresponding to the starting point is the first transmittance, and the transmittance corresponding to the ending point is the second transmittance. The difference between the second transmittance and the first transmittance is calculated; the third transmittance and the fourth transmittance are determined according to the difference, the third transmittance is the sum of 10% of the difference and the first transmittance, and the fourth transmittance is the sum of 80% of the difference and the first transmittance; the first coordinate point is determined on the target curve according to the third transmittance, and the third transmittance is the transmittance corresponding to the first coordinate point; the second coordinate point is determined on the target curve according to the fourth transmittance, and the fourth transmittance is the transmittance corresponding to the second coordinate point; the slope of the line connecting the first coordinate point and the second coordinate point is determined as the first slope K, referring to FIG. 5, the slope of the straight line l1 is the first slope K. In this way, the rising trend of the transmittance change is represented by selecting the points in the middle section of the change curve, avoiding the inaccuracy of the transmittance at the beginning or end of charging, which affects the test error; the slope of the straight line l1 can accurately represent the rising trend of the transmittance change curve, ensuring the accuracy of the measurement results.

[0074] In some embodiments, the rate of change of the electric field intensity of each corner of the electrochromic device is set to be lower than a threshold value set by the product to avoid premature failure due to excessive rate of change of the electric field intensity of a corner of the electrochromic device. Specifically, when K is less than K1, the rate of change of the electric field intensity of the target point is lower than the preset threshold value, where 0 < K1 < 10. It should be noted that the value of K1 is related to the material selection, the length of the electrode arrangement, and the angle of the electrode arrangement. The value of K1 is different for different products, but the same for each corner of the same product. The value of K1 for each corner of the same product can be set by test results and empirical formula. The value of K1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, etc. For example, when K1 is 5, the value of K obtained from the transmittance change curve of the transmittance change of the point a with time is less than 5, then the rate of change of the electric field intensity of the point a is less than the preset threshold value, indicating that the first corner can meet the cycle performance requirement of the product. Similarly, the determination method of the rate of change of the electric field intensity of the points b, c, and d is the same as that of the point a. When the value of K obtained from the transmittance change curve of the transmittance change of the points a, b, c, and d with time is less than 5, the rate of change of the electric field intensity of the points a, b, c, and d is less than the preset threshold value, indicating that the first corner, the second corner, the third corner, and the fourth corner can all meet the cycle performance requirement of the product. The position of the current circuit board connected to the electrochromic device is determined as the electrode lead-out position. It should be noted that the slope threshold K1 is related to the material of the electrochromic device and the area of the electrochromic device. Generally, the value of the slope threshold K1 is an empirical value verified by tests. It should be noted that the above only illustrates an example in which the preset condition is full charging. In other embodiments, when the preset condition is full discharging, the method of confirming the slope can also refer to the confirmation method in the full charging example. When the preset condition is one cycle of full charging and full discharging, the slopes corresponding to the two stages are used as evaluation criteria to further improve the accuracy of the position confirmation of the lead-out structure.

[0075] In some preferred embodiments, the preset threshold value can be the average value of each target point last time + 10%. For example, the rate of change of the electric field intensity of the points a, b, c, and d is 3, 4, 5, and 4, respectively, and the average value is 4. The preset threshold value is 4.4. When the electric field intensity of each point is less than 4.4, the current position is considered to be the position of the lead-out structure that meets the conditions.

[0076] By means of the technical solutions of the above embodiment, the transmittance of the target point in the corner is measured, the transmittance change curve of the target point with time is obtained, the first slope of the transmittance change curve is determined, and the electric field intensity of the target point is determined according to the first slope. When the first slopes K of the transmittance change curves of all the target points of the electrochromic device are less than K1, the position of the circuit board currently connected with the electrochromic device is determined as the electrode lead-out position on the electrochromic device, so that all the corners of the electrochromic device can reach the cycle performance required by the product, the measurement data is relatively more stable and accurate, and the accuracy of the electrochromic device is improved.

[0077] In some embodiments of the present application, the electric field intensity change rate is determined according to the change rate of the transmittance of the target point or the potential difference of the target point, comprising: measuring the potential difference of the target point during the charging or discharging process of the electrochromic device; when the potential difference of the target point rises to a first preset voltage or falls to a second preset voltage, the current time is determined as the first time, wherein the first preset voltage is the peak value in the potential difference change process, and the second preset voltage is the valley value in the potential difference change process. The duration between the first time and the end time when the charging or discharging of the electrochromic device is completed is calculated; in other words, the duration from when the potential difference of the target point rises to the first preset voltage or falls to the second preset voltage to when the charging or discharging is completed is obtained. The electric field intensity change rate is determined according to the duration, and the duration is positively correlated with the change rate of the electric field intensity of the target point. That is, the longer the duration, the greater the electric field intensity change rate; the shorter the duration, the smaller the electric field intensity change rate. When the change of the voltage per second is less than 0.05V, it is considered that the voltage has reached the peak value or the valley value.

[0078] In some embodiments, the electrochromic device is connected to a battery cycle test cabinet, the electrochromic device is fully charged according to a first preset voltage, when the potential difference of the target point rises to the first preset voltage, the current time is determined as the first time; the duration T between the first time and the end time when the charging or discharging of the electrochromic device is completed is calculated, and the duration T is positively related to the change rate of the electric field intensity of the target point. In other embodiments, the electrochromic device is fully discharged according to a second preset voltage, when the potential difference of the target point falls to the second preset voltage, the current time is determined as the first time; the duration T between the first time and the end time when the charging or discharging of the electrochromic device is completed is calculated, and the duration T is positively related to the change rate of the electric field intensity of the target point. In still other embodiments, the electrochromic device is fully charged according to a first preset voltage and fully discharged according to a second preset voltage, so that the potential difference of the electrochromic device changes periodically. The first preset voltage and the second voltage are determined according to the electrochromic material. A stable change period is selected, and the potential difference of the target point is measured in the period. When the potential difference of the target point rises to the first preset voltage or falls to the second preset voltage, the current time is determined as the first time; the duration T between the first time and the end time when the charging or discharging of the electrochromic device is completed is calculated, and the duration T is positively related to the change rate of the electric field intensity of the target point, that is, the longer the duration, the shorter the time of the previous change stage, and at this time, the greater the change is corresponding, and vice versa, the shorter the duration, the longer the time of the previous change stage, and the slower the change in this stage is corresponding.

[0079] It should be noted that during the duration after reaching the first preset voltage or the second preset voltage, the potential difference will have a slight fluctuation, and the potential difference fluctuation value within 0.05V per unit time is ignored. Or in other words, when the voltage difference fluctuation value within 0.05V per unit time, it is considered that the charging of the electrochromic device reaches the peak value or the discharging has reached the valley value.

[0080] In some embodiments, the potential difference of the target points corresponding to the first corner, the second corner, the third corner and the fourth corner, i.e., the potential difference of points a, b, c and d, is measured by a multimeter respectively. The electrochromic device is connected to a battery cycle test cabinet, and the potential difference of the electrochromic device is periodically changed according to the cycle logic of the product corresponding to the electrochromic device. In order to ensure the stability of the data, the potential difference of points a, b, c and d is recorded from the second cycle after the device starts to cycle. The test can be performed every interval preset time during the change, and the potential difference change curve of the potential difference of each target point with time is drawn respectively. Referring to FIG. 6, taking point a as an example, FIG. 4 is the potential difference change curve of the potential difference of point a with time, the horizontal axis in the figure represents time, and the vertical axis represents the potential difference of point a. It can be seen that after the voltage is applied to the electrochromic device, the potential difference of point a gradually increases, and after the potential difference of point a reaches the peak value, the potential difference of point a remains unchanged. The time period during which the potential difference of point a remains unchanged is the duration T, for the convenience of understanding, the time period between the two dashed lines in the figure, the value of the duration T is positively correlated with the electric field intensity of point a. Of course, in other embodiments, the first preset voltage value can also be other values, which can be set by the user according to the needs to avoid larger voltage difference in the corners. In addition, the first preset voltage value can also be the average value of the potential difference of each point.

[0081] It should be noted that the greater the potential difference change rate, the greater the electric field intensity change rate, which will result in a greater probability of failure of the electrochromic device. The value of the duration T reflects the time during which the potential difference change curve of the electrochromic device maintains at the peak value after reaching the peak value, i.e., the greater the value of the duration T, the longer the electrochromic device is subjected to continuous high voltage, and the more likely the electrochromic device is to fail. Therefore, the value of T is positively correlated with the electric field intensity.

[0082] In some embodiments, the method further comprises: when the duration is less than a time threshold, determining that the electric field intensity of the target point is lower than a field intensity threshold, wherein the time threshold is less than 50s. In other embodiments, the time threshold is set according to the area and material of the electrochromic device. Generally speaking, when the area of the electrochromic device is 1 square meter, the corresponding total color change time is 90 to 120 seconds. The color change is more obvious in the first 50% of the time, so the time threshold can be 50% of the total color change time.

[0083] The time threshold T1 of the duration T value is set, when T is less than T1, the electric field intensity change rate of the target point is lower than the preset threshold, wherein 0s < T1 < 50s. It should be noted that the value of the time threshold T1 is related to the material selection, the electrode arrangement length and the included angle thereof, and is further related to the area of the electrochromic device. The value of T1 corresponding to different products is different, and the values of T1 corresponding to each corner of the same product are the same. The values of T1 corresponding to each corner of the same product can be set through test results and empirical formula, and the value of T1 can be 10s, 20s, 30s, 40s, etc. For example, when T1 is 30s, as long as T is less than 30s, the electric field intensity change rate of a point is lower than the preset threshold, indicating that the first corner can meet the product requirement of cycle performance. Similarly, the determination method of the electric field intensity change rate corresponding to b point, c point and d point is the same as that of the electric field intensity change rate of a point. When the values of T obtained from the potential difference change curve of the potential difference change of a point, b point, c point and d point with time are all less than 30s, the electric field intensity change rates of a point, b point, c point and d point are lower than the preset threshold, indicating that the first corner, the second corner, the third corner and the fourth corner can all meet the product requirement of cycle performance, and the current position of the circuit board connected with the electrochromic device is determined as the electrode lead-out position.

[0084] By using the technical solutions of the above embodiments, the potential difference of the target point is measured, the duration between the first time and the end time of the current change cycle is calculated, the electric field intensity is determined according to the duration, when the duration that the potential difference of all corners of the electrochromic device reaches the peak value and remains unchanged is less than the time threshold, the current position of the circuit board is determined as the electrode lead-out position of the electrochromic device, all corners can meet the product requirement of cycle performance, the measurement data is relatively more stable and accurate, and the strength of the electric field change is tested by testing the battery difference in the embodiments, which is more convenient than testing the transmittance of the electrochromic device.

[0085] As shown in FIG. 1, in some embodiments of the present application, the electrochromic device comprises a first substrate layer 1, a first conductive layer 2, an electrochromic layer 3, a second conductive layer 4 and a second substrate layer 5 which are sequentially stacked. The electrode lead-out position determination method of the electrochromic device further comprises: determining a first region and a second region corresponding to the target point, the first region and the second region at least partially do not coincide in the orthogonal projection on a preset plane, the preset plane is perpendicular to the thickness direction of the electrochromic device; opening a first groove in the first region on the first substrate layer, and opening a second groove in the second region on the second substrate layer, the groove depth direction of the first groove and the second groove is parallel to the thickness direction of the electrochromic device, the groove bottom of the first groove is the second conductive layer, and the groove bottom of the second groove is the first conductive layer; connecting a voltmeter for testing voltage to the second conductive layer at the first groove and the first conductive layer at the first groove, and testing the potential difference change of the place during the color changing process.

[0086] In some embodiments of the present application, the potential difference of the target point is measured, comprising: applying voltage to the electrochromic device, measuring the potential difference between the second conductive layer in the first groove and the first conductive layer in the second groove, and taking the potential difference between the second conductive layer in the first groove and the first conductive layer in the second groove as the potential difference of the target point.

[0087] In some embodiments, the first region and the second region can be completely disjointed or partially intersected. As shown in FIG. 7, in some specific embodiments, the first region is the E region in the figure, the second region is the F region in the figure, and the orthogonal projection of the first region and the second region on the preset plane is a circle. As shown in FIG. 8, the first substrate layer 1 is grooved along the outer contour of the first region in the thickness direction of the electrochromic device, and the first substrate layer 1, the first conductive layer 2 and the electrochromic layer 3 are sequentially cut off until the second conductive layer 4 is exposed. The second substrate layer 5 is grooved along the outer contour of the second region in the thickness direction of the electrochromic device, and the second substrate layer 5, the second conductive layer 4 and the electrochromic layer 3 are sequentially cut off until the first conductive layer 2 is exposed. After wiping off the color changing material at the exposed positions of the first conductive layer 2 and the second conductive layer 4, the conductive wires are respectively attached to the first conductive layer 2 and the second conductive layer 4, the voltage is applied to the electrochromic device, and the potential difference between the exposed position of the first conductive layer 2 and the exposed position of the second conductive layer 4 is measured by using the multimeter, which is the potential difference of the target point.

[0088] In some embodiments, the first region is a circular region with a radius of 2mm-3mm, and the second region is a circular region with a radius of 2mm-3mm. For example, the first region is a circular region with a radius of 2mm, and the second region is a circular region with a radius of 2mm, and the boundary of the first region is in contact with the boundary of the second region. For another example, the first region is a circular region with a radius of 3mm, and the second region is a circular region with a radius of 3mm, and the boundary of the first region is completely not overlapped with the boundary of the second region.

[0089] By using the technical solutions of some embodiments, the second conductive layer 4 is exposed by slotting the first substrate layer 1 along the thickness direction of the electrochromic device, the first conductive layer 2 is exposed by slotting the second substrate layer 5 along the thickness direction of the electrochromic device, and then a more accurate potential difference of the target point is obtained by measuring the potential difference between the exposed positions of the first conductive layer 2 and the second conductive layer 4.

[0090] In some embodiments of the present application, the corner includes an angle region formed by the intersection of two adjacent boundary lines of the electrochromic device, the corner includes a first boundary line and a second boundary line, and the intersection of the first boundary line and the second boundary line is a vertex of the corner. The electrode located on the first boundary line close to the vertex is a first electrode, and the first electrode has a first end and a second end arranged oppositely, and the first end is close to the vertex. The electrode located on the second boundary line close to the vertex is a second electrode, and the second electrode has a third end and a fourth end arranged oppositely, and the third end is close to the vertex.

[0091] In some embodiments of the present application, the method for determining the electrode lead-out position of the electrochromic device further includes: determining a first straight line l2, a second straight line l3, a third straight line l4, and a fourth straight line l5 of the electrochromic device, wherein the first straight line l2 is a line connecting the first end and the third end, the second straight line l3 is a line connecting the second end and the fourth end, the third straight line l4 is a line connecting the midpoint of the first electrode and the midline of the second electrode, and the fourth straight line l5 is an angle bisector of the corner; determining the intersection points of the fourth straight line l5 and the first straight line l2, the second straight line l3, and the third straight line l4 as candidate point positions respectively; and taking the candidate point position with the largest electric field intensity as the target point position. In this way, the electric field intensity of the target point position is larger than that of other point positions in the corner, which is beneficial to making the overall electric field intensity distribution of the electrochromic device more uniform, avoiding the local corner region from having too high electric field intensity, and thus avoiding the local corner region of the electrochromic device from failing.

[0092] In some embodiments, as shown in FIG. 9, taking the case of an acute corner as an example, the two boundary lines of the corner are the first boundary line and the second boundary line, the first electrode 6 is arranged on the first boundary line, the first electrode 6 is connected with the negative electrode of the power supply, the second electrode 7 is arranged on the second boundary line, the second electrode 7 is connected with the positive electrode of the power supply, and the line connecting the first end of the first electrode 6 and the third end of the second electrode 7 is the first straight line l2. The line connecting the second end of the first electrode 6 and the fourth end of the second electrode 7 is the second straight line l3, the line connecting the midpoint of the first electrode 6 and the midpoint of the second electrode 7 is the third straight line l4, and the angle bisector of the corner is the fourth straight line l5. The intersection points of the first straight line l2, the second straight line l3, and the third straight line l4 with the fourth straight line l5 are the candidate point a1, the candidate point a2, and the candidate point a3, respectively. The electric field intensity of each candidate point is measured, and the candidate point with the highest electric field intensity is the target point. For example, the electric field intensity of the candidate point a1 is the highest, and the candidate point a1 is the target point of the corner. Thus, the electrode lead-out position of the electrochromic device is determined to minimize the probability of a large electric field intensity in the corner. In some embodiments, as shown in FIG. 10, the corner end point is a rounded corner, and the method for determining the candidate point is the same as that of the acute corner, which will not be described again.

[0093] In some embodiments of the present application, the relative position of the power supply and the electrochromic device is changed according to the change rate of the electric field intensity, including: changing the position of the power supply connected to the electrochromic device along a preset path, and the preset path is along the edge of the electrochromic device, away from the corner region corresponding to the target point with a large change rate of the electric field intensity, or close to the corner region corresponding to the target point with a small change rate of the electric field intensity. In some embodiments, the circuit board is moved from the corner corresponding to the target point with the largest change rate of the electric field intensity to the corner corresponding to the target point with the smallest change rate of the electric field intensity, every 3-10 mm, and then the change rate of the electric field intensity of each target point is measured and calculated. For example, the electric field intensity of each target point is measured and calculated every 5 mm, until the change rate of the electric field intensity of all target points is lower than a preset threshold, the circuit board stops moving, and the current position of the circuit board connected to the electrochromic device is determined as the electrode lead-out position.

[0094] In some embodiments, the relative position of the power supply and the electrochromic device is changed according to the change rate of the electric field intensity, which can also be that a plurality of lead-out structures are arranged on the edge of the electrochromic device, the plurality of lead-out structures can be uniformly arranged, and then different lead-out structures are controlled to be electrically connected with the power supply by software, so as to achieve the purpose of changing the relative position of the power supply and the electrochromic device.

[0095] In some embodiments, the positive electrode and the negative electrode of the circuit board are integrated on the same circuit board.

[0096] Referring to FIG. 2, in some embodiments of the present application, the circuit board comprises a first circuit board 8 and a second circuit board 9, the positive pole of the power supply can be connected with the first circuit board 8, the negative pole of the power supply can be connected with the second circuit board 9, the first circuit board 8 is connected with the first conductive layer 2, the second circuit board 9 is connected with the second conductive layer 4, and the first circuit board 8 and the second circuit board 9 are at least separated by a corner. For example, the first circuit board 8 and the second circuit board 9 are arranged on opposite edges of the electrochromic device, respectively.

[0097] By using the technical solutions of some embodiments of the present application, since the position of the circuit board is prone to overcharge and overdischarge, by making the first circuit board 8 and the second circuit board 9 at least separated by a corner, the distance between the first circuit board 8 and the second circuit board 9 can be increased, for example, by moving the first circuit board 8 and the second circuit board 9 along the connecting line between them in the direction away from the electrochromic device, the distance between the first circuit board 8 and the second circuit board 9 can reach 10-15 cm, the electric field intensity of the electrochromic device as a whole can be reduced, the electric field intensity of each target point can be ensured to be lower than the threshold value, and the failure caused by too large electric field intensity at the corner can be avoided.

[0098] Some embodiments of the present application provide an electrochromic device, and the electrode lead-out position of the electrochromic device is determined by using the method of any one of the above embodiments.

[0099] Since the method for confirming the electrode lead-out position of the electrochromic device is used, all the advantages of the above embodiments are achieved, and the technical effects of uniform electric field intensity and delayed failure are achieved.

[0100] The above only describes optional embodiments of the present application and does not limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of determining an electrode lead-out position of an electrochromic device, characterized by, The method comprises: obtaining the electric field intensity of a target point in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition; changing the relative position of the electrochromic device and the power supply according to the change rate of the electric field intensity; obtaining the electric field intensity of the target point in the electrochromic device during charging or discharging of the electrochromic device according to a preset condition again; when the change rates of the electric field intensities of the target points are all lower than a preset threshold, determining the position of the current power supply connected to the electrochromic device as the electrode lead-out position.

2. The method of claim 1, wherein, The method comprises: obtaining the transmittance of the target point or the potential difference of the target point during charging or discharging of the electrochromic device; determining the change rate of the electric field intensity according to the change rate of the transmittance or the potential difference.

3. The method of claim 2, wherein, The method comprises: obtaining the transmittance of the target point during charging or discharging of the electrochromic device; obtaining a transmittance change curve of the transmittance of the target point with time, determining a first slope of the transmittance change curve; determining the change rate of the electric field intensity of the target point according to the first slope, the value of the first slope being positively correlated with the change rate of the electric field intensity of the target point.

4. The method of claim 3, wherein, When the absolute value of the first slope is less than a slope threshold, it is determined that the change rate of the electric field intensity of the target point is lower than the preset threshold, wherein the threshold of the absolute value of the slope is greater than 0 and less than 10.

5. The method of claim 2, wherein, The method comprises: measuring the potential difference of the target point during charging or discharging of the electrochromic device; when the potential difference of the target point rises to a first preset voltage or falls to a second preset voltage, determining a first time point as the current time point; calculating the duration between the first time point and an end time point when the charging or discharging of the electrochromic device is completed; determining the change rate of the electric field intensity according to the duration, the duration being positively correlated with the change rate of the electric field intensity of the target point.

6. The method of claim 5, wherein, The method further comprises: when the duration is less than a time threshold, it is determined that the change rate of the electric field intensity of the target point is lower than the preset threshold.

7. The method according to any one of claims 1 to 6, characterized in that, The target point is a point in a corner region of the electrochromic device.

8. The method according to any one of claims 1 to 6, characterized in that, The preset condition is full charging of the electrochromic device according to a first preset voltage and / or full discharging of the electrochromic device according to a second preset voltage.

9. The method according to any one of claims 1 to 6, characterized in that, The method comprises: changing the position of the power supply connected to the electrochromic device along a preset path, the preset path being along an edge of the electrochromic device, away from a corner region corresponding to a target point with a larger change rate of the electric field intensity, or close to a corner region corresponding to a target point with a smaller change rate of the electric field intensity.

10. An electrochromic device, the electrode lead-out position of which is determined using the method of any one of claims 1-9.

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