A method of controlling an electrochromic device

Abstract

The application relates to the technical field of electrochromic technology, in particular to a control method of an electrochromic device, which comprises the following steps: changing working cut-off conditions of the electrochromic device under the same charging and discharging voltage, and obtaining the tolerance charging and discharging degree under each working cut-off condition; changing the charging and discharging voltage of the electrochromic device under each working condition under the same tolerance charging and discharging degree; and selecting the charging and discharging voltage with the best stability under the same cycle number as the optimal charging and discharging voltage. The application effectively improves the cycle stability of the electrochromic device by determining the tolerance charging and discharging degree of the electrochromic device and optimizing the charging and discharging voltage scheme, and further improves the cycle life of the device by adjusting the control logic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochromic technology, and in particular to a control method of an electrochromic device. BACKGROUND

[0002] After a long period of use, electrochromic device products will show signs of aging, especially under high temperature conditions, the decay is more significant; experiments show that the degree of device aging will differ when using different control logic for power cycling, so using inappropriate control logic will seriously affect the stability and service life of the electrochromic device.

[0003] To improve the stability of the electrochromic device during use, the influence of different conditions (cut-off conditions, control voltage, etc.) in the control logic on the stability of the device needs to be determined; through comparative experiments of multiple control logics, the optimal control logic for the type of electrochromic device can be selected; to improve the stability of the electrochromic device, the existing method usually takes certain protective measures on the control logic, such as reducing the working voltage, setting a limit current, etc. This solution sacrifices the color-changing speed of the device and does not significantly improve the stability. SUMMARY

[0004] One object of the present application is to provide a control method of an electrochromic device to solve the problems raised in the background art, i.e. to improve the stability of the electrochromic device, the existing method usually takes certain protective measures on the control logic, such as reducing the working voltage, setting a limit current, etc. This solution sacrifices the color-changing speed of the device and does not significantly improve the stability. The present application provides a control method of an electrochromic device, which effectively improves the cycle stability of the electrochromic device by determining the tolerance of the device to charging and discharging and optimizing the charging and discharging voltage scheme.

[0005] The technical solution adopted by the present application is as follows: the method comprises:

[0006] Changing the working cut-off conditions of the electrochromic device under the same charging and discharging voltage to obtain the tolerance of charging and discharging under each working cut-off condition;

[0007] Under the same tolerance of charging and discharging, changing the charging and discharging voltage of the electrochromic device under each working condition, and selecting the best charging and discharging voltage with the best stability under the same number of cycles as the best charging and discharging voltage.

[0008] As a preferred technical solution of the present application: the working cut-off condition is any one or a combination of multiple of capacity, current and time.

[0009] As a preferred technical solution of the present invention, the step of changing the working cut-off condition of the electrochromic device under the same charge and discharge voltage to obtain the charge and discharge tolerance under each working cut-off condition comprises:

[0010] Changing the electrochromic device's operating cutoff condition at the current charge and discharge voltage so that the electrochromic device reaches the current cutoff charge and discharge level;

[0011] Under a first preset number of cycles, performing a performance test on the electrochromic device with a first test period as a period to obtain a first performance change index;

[0012] When the number of test cycles of the electrochromic device reaches the first preset number of cycles and the first performance change index meets the required performance index, the current cutoff charge and discharge degree is defined as the tolerance charge and discharge degree.

[0013] As a preferred technical solution of the present invention, the method of changing the charge and discharge voltage of the electrochromic device under various operating conditions under the same charge and discharge tolerance and selecting the charge and discharge voltage with the best stability under the same number of cycles as the optimal charge and discharge voltage includes:

[0014] Under the current charge and discharge level, changing the charge and discharge voltage of the electrochromic device and obtaining the current charge and discharge voltage, so that the electrochromic device obtains the current charge and discharge response time under a second preset number of cycles, and performing a performance test on the electrochromic device with a second test cycle as a period to obtain a second performance change index;

[0015] The current charge and discharge voltage with the best second performance change index under the second preset number of cycles is selected as the optimal charge and discharge voltage.

[0016] As a preferred technical solution of the present invention: the target transmittance open-circuit voltage ≤ the current charge and discharge voltage ≤ the electrochemical window voltage of the material of the electrochromic device.

[0017] As a preferred technical solution of the present invention: the required performance indicators include the change rate of bright state transmittance, the change rate of dark state transmittance, the change value of charge and discharge response time and the appearance failure condition under a preset number of cycles.

[0018] As a preferred technical solution of the present invention: the second performance change indicator is the stability of the electrochromic device.

[0019] The present invention effectively improves the cycle stability of the electrochromic device by determining the charge and discharge tolerance of the electrochromic device and optimizing the charge and discharge voltage scheme, and further improves the cycle life of the device by adjusting the control logic. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is a diagram showing the transmittance change before and after the test at the center point of Example 1 of the present invention;

[0021] Figure 2 This is a graph showing the change in charging time before and after the test of Example 1 of the present invention;

[0022] Figure 3 This is a graph showing the change in discharge time before and after the test of Example 1 of the present invention;

[0023] Figure 4 A comparison diagram of the device appearances of experimental group 1 and experimental group 2 of Example 1 of the present invention;

[0024] Figure 5 This is a diagram showing the transmittance change before and after the test at the center point of Example 2 of the present invention;

[0025] Figure 6 This is a graph showing the change in charging time before and after the test of Example 2 of the present invention;

[0026] Figure 7 This is a graph showing the change in discharge time before and after the test of Example 2 of the present invention;

[0027] Figure 8 A comparison diagram of the device appearances of experimental group 1 and experimental group 2 of Example 2 of the present invention;

[0028] Figure 9 This is a diagram showing the transmittance change before and after the test at the center point of Example 3 of the present invention;

[0029] Figure 10 This is a graph showing the change in charging time before and after the test of Example 3 of the present invention;

[0030] Figure 11 This is a graph showing the change in discharge time before and after the test of Example 3 of the present invention;

[0031] Figure 12 3 is a comparison diagram of the device appearance of experimental group 1 and experimental group 2 of Example 3 of the present invention. DETAILED DESCRIPTION

[0032] It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of this application can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] A preferred embodiment of the present invention provides a method for controlling an electrochromic device, the method comprising:

[0034] Changing the working cut-off conditions of the electrochromic device at the same charge and discharge voltage to obtain the charge and discharge tolerance under each working cut-off condition;

[0035] Under the same charge and discharge tolerance level, the charge and discharge voltage of the electrochromic device under various working conditions is changed, and the charge and discharge voltage with the best stability under the same number of cycles is selected as the optimal charge and discharge voltage.

[0036] The working cut-off condition is any one or more combinations of capacity, current and time.

[0037] Changing the working cut-off conditions of the electrochromic device at the same charge and discharge voltage to obtain the charge and discharge tolerance under each working cut-off condition includes:

[0038] Changing the electrochromic device's operating cutoff condition at the current charge and discharge voltage so that the electrochromic device reaches the current cutoff charge and discharge level;

[0039] Under a first preset number of cycles, performing a performance test on the electrochromic device with a first test period as a period to obtain a first performance change index;

[0040] When the number of test cycles of the electrochromic device reaches the first preset number of cycles and the first performance change index meets the required performance index, the current cutoff charge and discharge degree is defined as the tolerance charge and discharge degree.

[0041] Under the same charge and discharge tolerance, changing the charge and discharge voltage of the electrochromic device under various working conditions, and selecting the charge and discharge voltage with the best stability under the same number of cycles as the optimal charge and discharge voltage includes:

[0042] Under the current charge and discharge level, changing the charge and discharge voltage of the electrochromic device and obtaining the current charge and discharge voltage, so that the electrochromic device obtains the current charge and discharge response time;

[0043] Under a second preset number of cycles, performing a performance test on the electrochromic device with a second test period as a period to obtain a second performance change index;

[0044] The current charge and discharge voltage with the best second performance change index under the second preset number of cycles is selected as the optimal charge and discharge voltage.

[0045] The target transmittance open-circuit voltage is ≤ the current charge and discharge voltage ≤ the electrochemical window voltage of the material of the electrochromic device.

[0046] The required performance indicators include the change rate of bright state transmittance, the change rate of dark state transmittance, the change value of charge and discharge response time and the appearance failure status under the preset number of cycles.

[0047] The second performance change index is the stability of the electrochromic device.

[0048] Embodiment 1: Taking the determination of the charging level resistant to high-temperature 85°C cycling as an example, the following two groups of experiments are set up:

[0049]

[0050]

[0051] The electrochromic device has a size of 300 x 300 mm.

[0052] The first preset cycle number is defined as 30,000 cycles. After the cycle aging, the performance of the device is required to have the following performance indexes: the change rate of the bright-state transmittance is less than or equal to 10%, the change value of the dark-state transmittance is less than or equal to 1%, the discharge response time is increased by less than or equal to 50 s, and there is no appearance failure.

[0053] According to the above, the charging level of the experimental group 1 is 76%, and the charging level of the experimental group 2 is 62%. The experimental results are as follows Figures 1-4 :

[0054] According to the experimental results, after 10,000 cycles of the experimental group 1, the change rate of the bright-state transmittance is greater than 10%, the change value of the dark-state transmittance is less than or equal to 1%, the discharge response time is increased by more than 50 s, and there is appearance failure. After 30,000 cycles of the experimental group 2, the change rate of the bright-state transmittance is less than or equal to 10%, the change value of the dark-state transmittance is less than or equal to 1%, the response time is increased by less than or equal to 50 s, and there is no appearance failure.

[0055] Therefore, the charging level resistant to high-temperature 85°C cycling is 62%, and when the charging level is 76%, the device is severely degraded.

[0056] It should be noted that the present embodiment only demonstrates part of the experimental content for example, and can be further refined in practice, for example, an experimental group with a charging level of 70% is set up to determine the highest charging level resistant to 85°C cycling.

[0057] Embodiment 2: Taking the determination of the charging voltage resistant to high-temperature 85°C cycling as an example, the following three groups of experiments are set up:

[0058]

[0059] The device has a size of 300 x 300 mm.

[0060] According to the above, the charging time of the experimental group 3 at high temperature 85°C is 36 s, the charging time of the experimental group 4 at high temperature 85°C is 22 s, and the charging time of the experimental group 5 at high temperature 85°C is 15 s. The second preset cycle number is defined as 10,000 cycles, and the performance of the device after the cycle is compared. The results are as follows Figure 5-Figure 8 :

[0061] According to the experimental results, after 10,000 cycles of experimental group 3, the transmittance in the bright state was higher than that in the initial state, and the stability was optimal.

[0062] As shown above, using a 1V charging voltage results in the shortest time the device spends under the applied electric field, resulting in optimal stability. However, due to the current limiting condition, further increasing the voltage is of little use.

[0063] Example 3: Example 3 is a supplement to Example 2. A sample with a size of 453ⅹ740mm is used to verify the feasibility of the high-voltage charging solution to improve stability.

[0064] Taking the determination of the high temperature 85℃ cycle charging voltage as an example, the following two sets of experiments are set up:

[0065]

[0066] According to the above, the high temperature 85℃ charging time of experimental group 6 is 142s, and the high temperature 85℃ charging time of experimental group 7 is 76s. The second preset number of cycles is defined as 5000 cycles. The performance of the device after the cycle is compared. The results are as follows Figures 9-12 :

[0067] According to the experimental results, after 5,000 cycles, the bright state of experimental group 6 decayed significantly and the appearance failed. The stability of experimental group 7 was better, which further verified that by increasing the charging voltage, the device had the shortest time under the action of the external electric field and the best stability.

[0068] It should be noted that the above embodiment only shows part of the experimental content for example, and can actually be further refined, such as increasing the charging voltage to 1V.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0070] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for controlling an electrochromic device, characterized in that: The method comprises: Changing the working cut-off conditions of the electrochromic device at the same charge and discharge voltage to obtain the charge and discharge tolerance under each working cut-off condition; Under the same charge and discharge tolerance, changing the charge and discharge voltage of the electrochromic device under various working conditions, and selecting the charge and discharge voltage with the best stability under the same number of cycles as the optimal charge and discharge voltage; Changing the working cut-off condition of the electrochromic device under the same charge and discharge voltage to obtain the charge and discharge tolerance under each working cut-off condition comprises: Changing the electrochromic device's operating cutoff condition at the current charge and discharge voltage so that the electrochromic device reaches the current cutoff charge and discharge level; Under a first preset number of cycles, performing a performance test on the electrochromic device with a first test period as a period to obtain a first performance change index; When the number of test cycles of the electrochromic device reaches the first preset number of cycles and the first performance change index meets the required performance index, defining the current cutoff charge and discharge degree as the tolerance charge and discharge degree; The method of changing the charge and discharge voltage of the electrochromic device under various operating conditions under the same charge and discharge tolerance and selecting the charge and discharge voltage with the best stability under the same number of cycles as the optimal charge and discharge voltage includes: Under the current charge and discharge level, changing the charge and discharge voltage of the electrochromic device and obtaining the current charge and discharge voltage, so that the electrochromic device obtains the current charge and discharge response time; Under a second preset number of cycles, performing a performance test on the electrochromic device with a second test period as a period to obtain a second performance change index; The current charge and discharge voltage with the best second performance change index under the second preset number of cycles is selected as the optimal charge and discharge voltage.

2. The method for controlling an electrochromic device according to claim 1, wherein: The working cut-off condition is any one or more combinations of capacity, current and time.

3. The control method of the electrochromic device according to claim 1, characterized in that: The target transmittance open-circuit voltage is ≤ the current charge and discharge voltage ≤ the electrochemical window voltage of the material of the electrochromic device.

4. The control method of the electrochromic device according to claim 1, characterized in that: The required performance indicators include the rate of change of bright state transmittance, the rate of change of dark state transmittance, the change value of charge and discharge response time and the appearance failure condition under a preset number of cycles.

5. The control method of the electrochromic device according to claim 1, characterized in that: The second performance change indicator is the stability of the electrochromic device.

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