Control circuit of electrochromic device, rearview mirror system and vehicle

Abstract

The invention discloses a control circuit of an electrochromic device, a rearview mirror system and a vehicle. The control circuit of the electrochromic device comprises a switch module, a control module and a control module, a first end of the switch module is connected with a first end of a first external power supply for supplying power to the electrochromic device, a second end of the switch module is connected with a second end of the first external power supply and a first electrode of the electrochromic device, and the switch module is used for responding to disconnection of the first external power supply to be automatically switched on. The first electrode of the electrochromic device and the second electrode of the electrochromic device are short-circuited. The control circuit can control the switch module to be switched on when the first external power supply is switched off, so that the first electrode of the electrochromic device and the second electrode of the electrochromic device are short-circuited, automatic short-circuit control is achieved, the discharging speed of the electrochromic device is increased, the electrochromic device achieves the effect of rapid color fading, and the service life of the electrochromic device is prolonged. The circuit does not need a processor or a control unit, and is simple in structure, reliable in circuit connection and low in cost and power consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicles, in particular to a control circuit of an electrochromic device, a rearview mirror system and a vehicle. BACKGROUND

[0002] In the related art, an electrochromic device can undergo reversible color change under the action of an applied electric field, and an electrochromic material undergoes reversible oxidation-reduction reaction at the two electrodes, and loses or gains electrons to adjust the transmittance and reflectance of the device. However, there is ion migration in the process of the electrochromic material losing or gaining electrons at the electrode, and the response rate of the device greatly depends on the migration rate of the color-changing material. In addition, during the power-on process of the device, the electrochromic material not only moves longitudinally between the two electrodes, but also has lateral diffusion. After the additional electric field disappears, the diffused color-changing material can only exchange charges slowly, so that the color slowly returns to the initial state after power-off. Moreover, the existing technology has complex circuit connection, high cost and power consumption, and cannot realize automatic control. SUMMARY

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present application is to propose a control circuit of an electrochromic device, which can control the switch module to be turned on when the first external power source is disconnected, so as to short-circuit the first electrode of the electrochromic device and the second electrode of the electrochromic device, realize automatic short-circuit control, improve the discharging speed of the electrochromic device, so as to achieve the effect of rapid fading of the electrochromic device, and the circuit does not need a processor or a control unit, the structure is simple, the circuit connection is reliable, the cost and power consumption are low.

[0004] A second object of the present application is to propose a rearview mirror system.

[0005] A third object of the present application is to propose a vehicle.

[0006] In order to solve the above problems, the first aspect of the present application provides a control circuit of an electrochromic device, comprising: a switch module, a first end of the switch module is connected with a first end of a first external power source for supplying power to the electrochromic device, a second end of the switch module is connected with a second end of the first external power source and a first electrode of the electrochromic device, and the switch module is used to automatically turn on in response to disconnection of the first external power source, so as to short-circuit the first electrode of the electrochromic device and a second electrode of the electrochromic device.

[0007] According to the control circuit of the electrochromic device of the present invention, the switching module is turned on or off in response to the on / off state of the first external power supply. When the first external power supply is off, the switching module is turned on to short-circuit the first electrode and the second electrode of the electrochromic device, thereby realizing automatic short-circuit control, improving the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading. Moreover, the circuit does not require a processor or control unit, has a simple structure, reliable circuit connection, and low cost and power consumption.

[0008] In some embodiments, when the first external power supply is disconnected, the switching module satisfies the following:

[0009]

[0010] Among them, R 开关模块电阻1 U is the resistance when the switching module is turned on. 电致变色器件电压 I is the voltage of the electrochromic device when the switching module is turned on. 开关模块电流 The current flowing through the switch module when the switch module is turned on.

[0011] In some embodiments, the switching module is further configured to be in an off state when the first external power supply is turned on, so that the first external power supply supplies power to the electrochromic device.

[0012] In some embodiments, when the first external power supply is turned on, the switching module satisfies the following:

[0013]

[0014] Among them, R 开关模块电阻2 U is the resistance when the switch module is disconnected. 电致变色器件电压 I is the voltage of the electrochromic device when the switching module is turned off. 电致变色器件电流 The current of the electrochromic device when the switching module is turned off.

[0015] In some embodiments, the switching module includes: a first transistor, the source of the first transistor being connected to a first terminal of the first external power supply and a second electrode of the electrochromic device, the drain of the first transistor being connected to a first electrode of the electrochromic device and a second terminal of the first external power supply, and the gate of the first transistor being connected to the drain of the first transistor, a first electrode of the electrochromic device and a second terminal of the first external power supply.

[0016] In some embodiments, the first transistor includes a junction field-effect transistor.

[0017] In some embodiments, the switching module further includes: a first diode, wherein the gate of the junction field-effect transistor is connected to the first electrode of the electrochromic device and the second terminal of the first external power supply through the first diode, the anode of the first diode is connected to the gate of the junction field-effect transistor, and the cathode of the first diode is connected to the first electrode of the electrochromic device and the second terminal of the first external power supply, for controlling the switching on and off of the junction field-effect transistor.

[0018] In some embodiments, the first diode is a silicon diode.

[0019] In some embodiments, the switching module includes: a normally closed relay, wherein a first terminal of the normally closed relay is connected to a first terminal of the first external power supply and a second electrode of the electrochromic device, a second terminal of the normally closed relay is connected to a first electrode of the electrochromic device and a second terminal of the first external power supply, and a third terminal of the normally closed relay is connected to the second terminal of the normally closed relay, a first electrode of the electrochromic device and a second terminal of the first external power supply.

[0020] In some embodiments, the control circuit further includes a current limiting module, wherein a first terminal of the current limiting module is connected to a first terminal of the switching module and a first terminal of the first external power supply, and a second terminal of the current limiting module is connected to a second electrode of the electrochromic device, for limiting the voltage input to the electrochromic device.

[0021] In some embodiments, when the first external power supply is disconnected, the current limiting module satisfies the following:

[0022]

[0023] R 等效电阻 =R 限流电阻 +R 电致变色器件电阻 ;

[0024] Among them, U 电致变色器件电压 R is the voltage of the electrochromic device when the switch module is turned on. 等效电阻 I is the equivalent resistance of the control circuit when the switching module is turned on. 放电电流 R is the discharge current of the electrochromic device. 限流电阻 R is the resistance of the current limiting module. 电致变色器件电阻 The resistance of the electrochromic device is given.

[0025] In some embodiments, when the first external power supply is turned on, the current limiting module satisfies:

[0026]

[0027] Among them, U第一外部电源电压 U is the voltage of the first external power supply. 电致变色器件电压 R is the voltage of the electrochromic device when the switching module is turned off. 限流电阻 R is the resistance of the current limiting module. 电致变色器件电阻 I is the resistance of the electrochromic device. 第一外部电源电流 This is the current supplied when the first external power source is turned on.

[0028] In some embodiments, the current limiting module includes an anti-reverse current unit, the first end of which is connected to the first end of the switching module and the first end of the first external power supply, and the second end of which is connected to the second electrode of the electrochromic device, for preventing the electrochromic device from reversing its input or output.

[0029] In some embodiments, the current limiting module further includes: a voltage regulating unit, wherein a first end of the voltage regulating unit is connected to a first end of the switching module and a first end of the first external power supply, and a second end of the voltage regulating unit is connected to a second electrode of the electrochromic device and a second end of the anti-reverse current unit, for voltage regulation.

[0030] In some embodiments, the anti-reverse current unit includes: a second diode, the cathode of the second diode being connected to a first terminal of the switching module and a first terminal of the first external power supply, and the anode of the second diode being connected to a second electrode of the electrochromic device.

[0031] In some embodiments, the voltage regulator unit includes: a fixed resistor, the first end of which is connected to the first end of the switching module and the first end of the first external power supply, and the second end of which is connected to the second electrode of the electrochromic device and the second end of the anti-reverse current unit.

[0032] In some embodiments, when the first external power supply is disconnected, the second diode and the fixed resistor satisfy the following:

[0033]

[0034] Among them, U 电致变色器件电压 R is the voltage of the electrochromic device. 第二二极管导通电阻 R is the on-resistance of the second diode. 定值电阻 I is the resistance value of the fixed resistor. 放电电流 The discharge current of the electrochromic device is denoted as .

[0035] In some embodiments, when the first external power supply is turned on, the second diode and the fixed resistor satisfy the following:

[0036]

[0037] Among them, U 第一外部电源电压 U is the voltage of the first external power supply. 电致变色器件电压 R is the voltage of the electro-hydraulic transmission device. 第二二极管截留电阻 R is the resistance when the second diode is turned off. 定值电阻 I is the resistance value of the fixed resistor. 第一外部电源电流 This is the current when the first external power source is turned on.

[0038] In some embodiments, the voltage regulator unit includes: a second transistor, the source of which is connected to a first terminal of the switching module and a first terminal of the first external power supply, and the drain of which is connected to a second electrode of the electrochromic device and an anode of the second diode; and a third diode, the anode of which is connected to the gate of the second transistor, and the cathode of which is connected to a second electrode of the electrochromic device and an anode of the second diode.

[0039] In some embodiments, the control terminal of the switch module is connected to a second external power supply, which is switched on and off synchronously with the first external power supply to control the switching on and off of the switch module.

[0040] In some embodiments, the switching module includes: a third transistor, the source of which is connected to a first terminal of the first external power supply and a first terminal of the second external power supply, the drain of which is connected to a first electrode of the electrochromic device and a second terminal of the first external power supply, and the gate of which is connected to a second terminal of the second external power supply.

[0041] A second aspect of the present invention provides a rearview mirror system, including an electrochromic device and a control circuit for the electrochromic device described in the above embodiments, wherein the control circuit is connected to the electrochromic device.

[0042] According to an embodiment of the present invention, when the first external power supply is disconnected, the control switch module is turned on, causing the first electrode and the second electrode of the electrochromic device to be short-circuited, thereby realizing automated short-circuit control, increasing the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading. This allows the rearview mirror to make corresponding adjustments quickly under different ambient light intensities, preventing driver dizziness. Furthermore, the circuit does not require a processor or control unit, has a simple structure, reliable circuit connection, and low cost and power consumption.

[0043] A third aspect of the present invention provides a vehicle including the rearview mirror system described in the above embodiments.

[0044] According to an embodiment of the present invention, in the rearview mirror system, when the first external power supply is disconnected, the control switch module is turned on, causing the first electrode and the second electrode of the electrochromic device to be short-circuited, thereby realizing automated short-circuit control, increasing the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading, allowing the rearview mirror to make corresponding adjustments quickly under different ambient light intensities, and preventing driver dizziness.

[0045] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0046] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0047] Figure 1 This is a schematic diagram of the control circuit of an electrochromic device according to an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of an electrochromic device according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of an equivalent model of an electrochromic device according to an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of a switching module according to an embodiment of the present invention;

[0051] Figure 5 This is a flowchart of a control method according to an embodiment of the present invention;

[0052] Figure 6 This is a schematic diagram of a current limiting module according to an embodiment of the present invention;

[0053] Figure 7 This is a schematic diagram of a current limiting module according to another embodiment of the present invention;

[0054] Figure 8 This is a schematic diagram of the control circuit of an electrochromic device according to another embodiment of the present invention;

[0055] Figure 9 This is a schematic diagram of the control circuit of an electrochromic device according to another embodiment of the present invention;

[0056] Figure 10 This is a structural block diagram of a rearview mirror system according to an embodiment of the present invention;

[0057] Figure 11 This is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0058] Figure label:

[0059] Vehicle 300;

[0060] Rearview mirror system 200;

[0061] Control circuit 100 for electrochromic device; Electrochromic device 130;

[0062] Switching module 110; First external power supply 120; Current limiting module 140; Second external power supply 150;

[0063] First transistor JFET31; First diode Si40; Anti-reverse current unit 141; Voltage regulator unit 142; Second diode Ge10; Fixed resistor R20; Second transistor JFET30; Third diode Ge11; Third transistor 111. Detailed Implementation

[0064] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0065] The first aspect of the present invention provides a control circuit for an electrochromic device. When the first external power supply is disconnected, the control circuit can control the switching module to conduct, so that the first electrode and the second electrode of the electrochromic device are short-circuited, thereby realizing automated short-circuit control, improving the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading. Moreover, the circuit connection is reliable and the cost and power consumption are low.

[0066] The following is for reference. Figure 1 The control circuit of the electrochromic device according to an embodiment of the first aspect of the present invention is described, such as... Figure 1 As shown, the control circuit 100 of the electrochromic device includes a switching module 110.

[0067] The first terminal of the switch module 110 is connected to the first terminal of the first external power supply 120 for supplying power to the electrochromic device 130, and the second terminal of the switch module 110 is connected to the second terminal of the first external power supply 120 and the first electrode of the electrochromic device 130. The switch module 110 is used to automatically turn on in response to the first external power supply 120 being disconnected, so as to short-circuit the first electrode and the second electrode of the electrochromic device 130.

[0068] Specifically, when the first external power supply 120 is closed, the switch module 110 is open. At this time, the first external power supply 120 supplies power to the electrochromic device 130, providing the voltage required for the electrochromic device 130 to change color, thus coloring the electrochromic material. When the first external power supply 120 is closed, the switch module 110 is closed. At this time, the first electrode and the second electrode of the electrochromic device 130 are short-circuited, and the electrochromic device 130 quickly exchanges charges to its initial state, thereby achieving the effect of rapid fading.

[0069] This invention relates to the field of short-circuit control methods, control circuits, and electronic components for electrochromic devices; for ease of description, this invention uses a liquid electrochromic device based on a viologen and methylphenazine system as an example, such as... Figure 2 As shown, the electrochromic device of the present invention includes a power control module, a first substrate, a second substrate, an electrochromic layer, a first conductive layer, a second conductive layer, an insulating layer, conductive adhesive, a cut wire, a first electrode, and a second electrode.

[0070] It is understandable that when an electrochromic device is energized, it can be represented as an equivalent parallel model of a diode and a capacitor, such as... Figure 3 As shown in the equivalent model of the electrochromic device, when the input voltage across the first and second electrodes is 1.2V, a portion of the current charges the capacitor until the stored voltage reaches approximately 0.6V, while the remaining current returns to the second electrode through the diode, causing the electrochromic material to color. At this point, the diode's resistance is approximately 6Ω-10Ω. When the external power supply is disconnected, the capacitor begins to discharge, with a discharge voltage ≤0.6V. Due to the high turn-on voltage of the diode, its resistance is ≥30Ω, resulting in a slow self-discharge rate. Furthermore, as the capacitor voltage decreases, the diode resistance continuously increases, necessitating an external short circuit to rapidly discharge the capacitor and restore it to its initial state.

[0071] According to the control circuit of the electrochromic device of the present invention, the switching module is turned on or off in response to the on / off state of the first external power supply. When the first external power supply is off, the switching module is turned on to short-circuit the first electrode and the second electrode of the electrochromic device, thereby realizing automatic short-circuit control, improving the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading. Moreover, the circuit does not require a processor or control unit, has a simple structure, reliable circuit connection, and low cost and power consumption.

[0072] In some embodiments, when the first external power supply is disconnected, the switching module satisfies:

[0073]

[0074] Among them, R 开关模块电阻1 U is the resistance when the switching module is turned on. 电致变色器件电压I is the voltage of the electrochromic device when the switching module is turned on. 开关模块电流 This refers to the current flowing through the switching module when it is turned on.

[0075] Specifically, when the first external power supply 120 is turned off, the switch module 110 is turned on, requiring the electrochromic device 130 to be shorted to discharge rapidly. Therefore, the resistance value of the switch module 110 when it is turned on needs to be less than the minimum resistance value required for the electrochromic device 130 to discharge rapidly. As shown in Table 1, U 第一外部电压、 U 电致变色器件电压 R 开关模块电阻 and I 开关模块电流 The corresponding relationship table is shown below:

[0076] Table 1U 第一外部电压、 U 电致变色器件电压 R 开关模块电阻 and I 开关模块电流 Correspondence table

[0077] U 第一外部电压 / V]] U 电致变色器件电压 / V]] [R 开关模块电阻 / Ω]] I 开关模块电流 / mA]]> 12 1.2±0.1 ≥5000 ≤1 5 1.2±0.1 ≥500 ≤10 3 1.2±0.1 ≥150 ≤20 1.2 1.2±0.1 ≥50 ≤25 0.8 0.8 (minimum operating voltage) ≥26 ≤30 0 0.6 ≤15 ≥40 0 0.5 ≤14 ≥35 0 0.3 ≤12 ≥25 0 0 ≤12 0

[0078] The switching module 110 needs to remain on in the low voltage region (0V-0.6V), that is, when the first external power supply 120 is disconnected, with the on-resistance R... 开关模块电阻1 ≤15Ω, conduction current I 开关模块电流 Only electrochromic devices of type 130 can fully discharge within 2s-3s with an input current of ≥25mA.

[0079] In some embodiments, the switching module is further configured to be in an off state when the first external power supply is turned on, so that the first external power supply supplies power to the electrochromic device.

[0080] Specifically, such as Figure 1 As shown, when the first external power supply 120 is turned on, the switch module 110 is in the off state. At this time, the first external power supply 120 supplies power to the electrochromic device 130, providing the voltage that satisfies the color change of the electrochromic device 130, so that the electrochromic material is colored.

[0081] In some embodiments, when the first external power supply is turned on, the switching module satisfies:

[0082]

[0083] Among them, R 开关模块电阻2 U is the resistance when the switching module is disconnected. 电致变色器件电压 I is the voltage of the electrochromic device when the switching module is disconnected. 电致变色器件电流 This represents the current in the electrochromic device when the switching module is disconnected.

[0084] Specifically, when the first external power supply 120 is turned on, the switch module 110 needs to be turned off. The first external power supply 120 supplies power to the electrochromic device 130, providing the voltage required for the electrochromic device 130 to change color, thus coloring the electrochromic material. Therefore, the resistance value of the switch module 110 needs to be greater than the maximum resistance value when the electrochromic device 130 can work normally, so that when the electrochromic device 130 is working normally, the switch module 110 is turned off and the first external power supply 120 supplies power to the electrochromic device 130.

[0085] In some embodiments, such as Figure 4 As shown, the switching module 110 includes: a first transistor JFET31.

[0086] In this configuration, the source S of the first transistor JFET31 is connected to the first terminal of the first external power supply 120 and the second electrode of the electrochromic device 130; the drain D of the first transistor JFET31 is connected to the first electrode of the electrochromic device 130 and the second terminal of the first external power supply 120; and the gate G of the first transistor JFET31 is connected to the drain D of the first transistor JFET31, the first electrode of the electrochromic device 130, and the second terminal of the first external power supply 120.

[0087] Specifically, the switching module 110 can be composed of transistors. Depending on the direction of the control voltage and the switching conditions, the transistor is preferably a junction field-effect transistor (JFET). When the external power supply voltage is higher than the transistor's turn-on voltage, the transistor is in a current-cut-off state; when the external power supply voltage is lower than the transistor's turn-on voltage, the transistor is in a conducting or partially conducting state. The JFET can be an N-type or a P-type JFET, and can be voltage-controlled or current-controlled.

[0088] In some embodiments, the first transistor JFET31 includes a junction field-effect transistor.

[0089] Specifically, a junction field-effect transistor (JFET) is a voltage-controlled semiconductor device, belonging to the field-effect transistor family. It controls the current magnitude by changing the gate voltage to control the width of the conductive channel between the source and drain. JFETs offer many advantages, such as high input impedance, low noise, low power consumption, and good temperature stability. These characteristics make JFETs widely used in analog circuits, audio amplifiers, voltage regulators, and switching circuits.

[0090] In some embodiments, such as Figure 4 As shown, the switching module 110 includes: a first diode Si40.

[0091] In this configuration, the gate G of the junction field-effect transistor JFET31 is connected to the first electrode of the electrochromic device 130 and the second terminal of the first external power supply 120 via the first diode Si40. The anode of the first diode Si40 is connected to the gate G of the junction field-effect transistor JFET31, and the cathode of the first diode Si40 is connected to the first electrode of the electrochromic device 130 and the second terminal of the first external power supply 120, thereby controlling the on / off state of the junction field-effect transistor JFET31.

[0092] Specifically, in some embodiments, when the external power supply voltage and the operating voltage of the electrochromic device are the same, taking the electrochromic device of the present invention as an example, when the operating voltage is 0.8V-1.2V, the control circuit 100 of the electrochromic device can be further simplified as follows: Figure 4 The circuit structure is shown. The current limiting module is simplified. The switching module 110 consists of a junction field-effect transistor (JFET31) and a first diode Si40. The function of the first diode Si40 is to remain in the conducting state when the first external power supply 120 is turned on, i.e., when the voltage is between 0.8V and 1.2V, thereby activating the gate G of the JFET31 and ensuring that the source S and drain D are in an open or high-resistance state. When the first external power supply 120 is turned off, the electrochromic device 130 discharges at a voltage ≤0.6V, which is insufficient to turn on the first silicon diode Si40 (turn-on voltage ≥0.7V). At this time, the gate G of the JFET31 cannot be turned on, and the source S and drain D are in a fully conducting state. The resistance value of the switching module 110 is at its lowest, and the discharge current of the electrochromic device 130 is at its maximum.

[0093] In some embodiments, the first diode Si40 is a silicon diode.

[0094] Specifically, a silicon diode is an important semiconductor device with unidirectional conductivity and many advantages, and it is widely used in various electronic circuits. A silicon diode is composed of P-type semiconductor and N-type semiconductor materials connected together to form a PN junction. When the anode of the diode is connected to the P-type semiconductor and the cathode is connected to the N-type semiconductor, the diode is in the conducting state and current can flow through the diode. When the polarity of the diode is reversed, that is, when the anode is connected to the N-type semiconductor and the cathode is connected to the P-type semiconductor, the diode is in the cut-off state and current cannot flow through it. This unidirectional conductivity is the basic characteristic of silicon diodes and the basis for their widespread application in various circuits.

[0095] In some embodiments, the switching module 110 includes a normally closed relay.

[0096] The first terminal of the normally closed relay is connected to the first terminal of the first external power supply 120 and the second electrode of the electrochromic device 130; the second terminal of the normally closed relay is connected to the first electrode of the electrochromic device 130 and the second terminal of the first external power supply 120; and the third terminal of the normally closed relay is connected to the second terminal of the normally closed relay, the first electrode of the electrochromic device 130 and the second terminal of the first external power supply 120.

[0097] Specifically, in some embodiments, when there is only one external power supply, the switch module 110 can also be composed of relay elements to achieve the same function as a transistor. In this case, the relay must be a normally closed relay. When the first external power supply 120 is turned on, the normally closed relay must remain open, and current flows from the first external power supply 120 through the current limiting module 140 into the electrochromic device 130. When the first external power supply 120 is turned off, the normally closed relay must remain closed or partially closed, allowing the discharge current of the electrochromic device 130 to pass through the normally closed relay, achieving a short-circuit function. Normally closed relays include electromagnetic relays and solid-state relays, which can be single-pole single-throw, single-pole double-throw, or double-pole double-throw.

[0098] The corresponding relationships between the relay's on-resistance, relay on-current, first external power supply voltage, and electrochromic device voltage are shown in Table 2 below:

[0099] Table 2U 第一外部电压 U 电致变色器件电压 R 继电器导通电阻 and I 继电器导通电流 Correspondence table

[0100] U 外部电源电压 / V]] U 电致变色器件电压 / V]] [R 继电器导通电阻 / Ω]] I 继电器导通电流 / mA <!-- 7 -->]]> 12 1.2±0.1 ≥5000 ≤1 5 1.2±0.1 ≥500 ≤10 3 1.2±0.1 ≥150 ≤20 1.2 1.2±0.1 ≥100 ≤25 0.8 0.8 ≥80 ≤30 0 0.6 ≤15 ≥40 0 0.5 ≤14 ≥35 0 0.3 ≤12 ≥25 0 0 ≤12 0

[0101] When the first external power supply is connected, the voltage of the first external power supply must be 0.8V ≤ 12V, and the following conditions must be met:

[0102]

[0103] When the first external power supply is disconnected, the voltage of the first external power supply is 0V, and the following conditions must be met:

[0104]

[0105] In some embodiments, such as Figure 1 As shown, the control circuit 100 of the electrochromic device includes a current limiting module 140.

[0106] The first end of the current limiting module 140 is connected to the first end of the switch module 110 and the first end of the first external power supply 120, and the second end of the current limiting module 140 is connected to the second electrode of the electrochromic device 130, which is used to limit the voltage input to the electrochromic device 130.

[0107] Specifically, in order to keep the electrochromic device 130 within its operating voltage range and prevent the current through the electrochromic device 130 from exceeding its rated current, a current limiting module 140 is added to the control circuit 100 of the electrochromic device. This allows the current from the first external power supply 120 to flow through the current limiting module 140 before supplying power to the electrochromic device 130, thus preventing damage to the electrochromic device 130 due to excessive current.

[0108] In some embodiments, when the first external power supply is disconnected, the current limiting module satisfies:

[0109]

[0110] R 等效电阻 =R 限流电阻 +R 电致变色器件电阻 ;

[0111] Among them, U 电致变色器件电压 R is the voltage of the electrochromic device when the switching module is turned on. 等效电阻 I is the equivalent resistance of the control circuit when the switching module is turned on. 放电电流 R is the discharge current of the electrochromic device. 限流电阻 R is the resistor for the current limiting module. 电致变色器件电阻 The resistor is for the electrochromic device.

[0112] Specifically, when the transistor is in the high-voltage region (0.8V-12V), a current-limiting module 140 needs to be connected in series with the electrochromic device 130 to ensure that the electrochromic device 130 is always within the operating voltage range (0.8V-1.2V), and the operating current of the electrochromic device 130 needs to be ≤150mA. The current-limiting module 140 can be composed of electronic components with variable resistance, such as current-limiting resistors, step-down components, voltage regulators, and diodes. The resistors in the current-limiting module 140 are collectively referred to as current-limiting resistors, i.e., R. 限流电阻 The entire circuit can be considered as an equivalent resistance, i.e., R. 等效电阻 , and U 第一外部电源电压 I 放电电流 and U 电致变色器件电压 The correspondence is shown in Table 3:

[0113] Table 3U 第一外部电源电压 U 电致变色器件电压 R 等效电阻 and I 放电电流 Correspondence table

[0114] U 第一外部电源电压 / V]]> U 电致变色器件电压 / V]] [R 等效电阻 / Ω]] I 放电电流 / mA]]> 12 1.2±0.1 72-90 120-150 5 1.2±0.1 25-31 120-150 3 1.2±0.1 13-17 120-150 1.2 1.2±0.1 ≤1 120-150 0.8 0.8 ≤1 90-110 0 0.6 ≤5 ≥40 0 0.5 ≤5 ≥35 0 0.3 ≤5 ≥25 0 0 ≤5 0

[0115] Since the current-limiting module 140 in the control circuit 100 of the electrochromic device is connected in series with the electrochromic device 130, the equivalent resistance is the sum of the current-limiting resistor and the electrochromic device resistance. Based on the voltage of the electrochromic device and the equivalent resistance, the discharge current of the electrochromic device 130 can be calculated. According to Table 3, I... 放电电流 ≥25mA.

[0116] In some embodiments, when the first external power supply is turned on, the current limiting module satisfies:

[0117]

[0118] Among them, U 第一外部电源电压 U is the voltage of the first external power supply. 电致变色器件电压 R is the voltage of the electrochromic device when the switching module is off. 限流电阻 R is the resistor for the current limiting module. 电致变色器件电阻 For the resistance of the electrochromic device, I 第一外部电源电流 This is the current supplied when the first external power source is turned on.

[0119] Specifically, when the first external power supply 120 is turned on, the switch module 110 is turned off, and the first external power supply 120 supplies power to the electrochromic device 130 through the current limiting module 140. At this time, the current limiting module 140 is connected in series with the electrochromic device 130, and the current flowing through the current limiting module 140 is equal to the current flowing through the electrochromic device 130. The maximum allowable current through the electrochromic device 130 is 150mA. Therefore, the current flowing through the current limiting module 140 is equal to the current flowing through the electrochromic device 130 and does not exceed 150mA. The maximum current of the first external power supply is 150mA.

[0120] In some embodiments, such as Figure 1 As shown, the current limiting module 140 includes: an anti-backflow unit 141.

[0121] The first end of the anti-reverse current unit 141 is connected to the first end of the switch module 110 and the first end of the first external power supply 120, and the second end of the anti-reverse current unit 141 is connected to the second electrode of the electrochromic device 130, which is used to prevent the electrochromic device 130 from being input or output in reverse.

[0122] Specifically, the anti-reverse current unit 141 is connected to the second electrode of the electrochromic device 130, ensuring that when the electrochromic device 130 discharges, the current can flow smoothly through the anti-reverse current unit 141. At the same time, the anti-reverse current unit 141 monitors and prevents the reverse flow of current to protect the components in the circuit from damage.

[0123] In some embodiments, such as Figure 1As shown, the current limiting module 140 includes a voltage regulator unit 142.

[0124] The first end of the voltage regulator unit 142 is connected to the first end of the switch module 110 and the first end of the first external power supply 120, and the second end of the voltage regulator unit 142 is connected to the second electrode of the electrochromic device 130 and the second end of the anti-reverse current unit 141, for voltage regulation.

[0125] Specifically, in order to keep the electrochromic device 130 within its operating voltage range and prevent the current through the electrochromic device 130 from exceeding its rated current, a voltage limiting and regulating unit 142 is added before the electrochromic device 130 to ensure the voltage of the electrochromic device 130 remains stable when the voltage of the first external power supply 120 fluctuates.

[0126] For example, the control circuit of the electrochromic device of the present invention is as follows: Figure 1 As shown, the first external power supply 120 is DC power provided by an external host or processor according to demand. For example, in the field of automotive anti-glare rearview mirrors, the operating voltage of the rearview mirror given by the automotive host according to the ambient light intensity can be 0.8V-1.2V, or it can be higher than the maximum operating voltage of the electrochromic device, such as 1.3V, 1.5V, 3V, 5V, 12V, etc.

[0127] The flow of the control method of the present invention is as follows: Figure 5 As shown, it includes at least steps S1 to S2.

[0128] Step S1: After the external power supply is turned on, the power control module controls the voltage to color the electrochromic material.

[0129] Specifically, when the external power supply is turned on, the current passes through the voltage regulator unit 142 and then reaches the first and second electrodes of the electrochromic device 130, causing the color-changing material to color. The switching module 110 automatically disconnects the circuit on this side according to the applied voltage to prevent short circuits. When the external voltage exceeds the maximum operating voltage of the electrochromic device 130, the voltage regulator unit 142 acts as a voltage divider, protecting the electrochromic device 130 within its operating voltage range. At this time, the anti-reverse current unit 141 is also in a cut-off state to prevent short circuits.

[0130] In step S2, after the external power supply is disconnected, the power control module short-circuit the first conductive layer and the second conductive layer, causing the electrochromic material to fade.

[0131] Specifically, when the external power supply is disconnected, the electrochromic device 130 is in a discharging state. At this time, the switch module 110 automatically turns on according to the status of the external power supply. The first electrode is now the negative electrode and the second electrode is the positive electrode. Current flows from the second electrode through the anti-reverse current unit 141, through the switch module 110, and back to the first electrode. At this time, the first electrode and the second electrode are essentially short-circuited, and the electrochromic device 130 discharges rapidly, returning to its initial state.

[0132] The discharge voltage of the electrochromic device 130 varies depending on the color-changing material. Taking a system with viologen and methylphenazine as the cathode and anode color-changing materials as examples, the maximum discharge voltage is 0.6V. When the voltage drops to 0V, it indicates that the electrochromic device 130 is fully discharged and the electrochromic material 130 has completely returned to its initial colorless state.

[0133] In some embodiments, such as Figure 6 As shown, the anti-reverse current unit 141 includes: a second diode Ge10.

[0134] The cathode of the second diode Ge10 is connected to the first terminal of the switch module 110 and the first terminal of the first external power supply 120, and the anode of the second diode Ge10 is connected to the second electrode of the electrochromic device 130.

[0135] Specifically, the second diode Ge10 is connected to the second electrode of the electrochromic device 130, ensuring that when the electrochromic device 130 discharges, the current can flow smoothly from the second diode Ge10 to the switching module 110. At the same time, the second diode Ge10 prevents the current from the first external power supply 120 from flowing through, so as to protect the electrochromic device 130 from damage.

[0136] In some embodiments, such as Figure 6 As shown, the voltage regulator unit 142 includes a fixed resistor R20.

[0137] The first end of the fixed resistor R20 is connected to the first end of the switch module 110 and the first end of the first external power supply 120, and the second end of the fixed resistor R20 is connected to the second electrode of the electrochromic device 130 and the second end of the anti-reverse current unit 141.

[0138] Specifically, the fixed resistor R20 is located between the first external power supply 120 and the electrochromic device 130. When the voltage of the first external power supply 120 is higher than the maximum operating voltage of the electrochromic device 130, the fixed resistor R20 can act as a voltage divider to protect the electrochromic device 130 from operating voltage range.

[0139] In some embodiments, when the first external power supply is disconnected, the second diode and the fixed resistor satisfy the following:

[0140]

[0141] Among them, U 电致变色器件电压 R is the voltage of the electrochromic device. 第二二极管导通电阻 R is the on-resistance of the second diode. 定值电阻 I is the resistance value of the fixed resistor. 放电电流 This represents the discharge current of the electrochromic device.

[0142] Specifically, the current limiting module 140 can be composed of a fixed resistor R20 and a second diode Ge10 connected in parallel, such as... Figure 6 As shown, the second diode Ge10 is in the off state when the first external power supply 120 is turned on, and in the fully conducting state when the first external power supply 120 is turned off. It needs to meet the requirements of high cut-off resistance and low on-resistance. The corresponding relationship is shown in Table 4.

[0143] Table 4U 第一外部电源电压 R 定值电阻 and R 第二二极管导通电阻 Correspondence table

[0144]

[0145] In some embodiments, when the first external power supply is turned on, the second diode and the fixed resistor satisfy the following:

[0146]

[0147] Among them, U 第一外部电源电压 U is the voltage of the first external power supply. 电致变色器件电压 R is the voltage of the electro-hydraulic transmission component. 第二二极管截留电阻 R is the resistance when the second diode is turned off. 定值电阻 I is the resistance value of the fixed resistor. 第一外部电源电流 This is the current when the first external power source is turned on.

[0148] Specifically, when the first external power supply 120 is turned on, the switch module 110 is turned off. Since the electrochromic device 130 also discharges, the voltage at the second diode Ge10 is the first external voltage minus the voltage of the electrochromic device; the voltage at the fixed resistor R20 is the first external voltage minus the voltage of the electrochromic device. Since the second diode Ge10 and the fixed resistor R20 are connected in parallel, the sum of the currents of the second diode Ge10 and the fixed resistor R20 is less than or equal to the current when the first external power supply is turned on.

[0149] In some embodiments, such as Figure 7 As shown, the voltage regulator unit 142 includes a second transistor JFET30 and a third diode Ge11.

[0150] In this configuration, the source S of the second transistor JFET30 is connected to the first terminal of the switching module 110 and the first terminal of the first external power supply 120; the drain D of the second transistor JFET30 is connected to the second electrode of the electrochromic device 130 and the anode of the second diode Ge10; the anode of the third diode Ge11 is connected to the gate G of the second transistor JFET30; and the cathode of the third diode Ge11 is connected to the second electrode of the electrochromic device 130 and the anode of the second diode Ge10.

[0151] Specifically, in some embodiments, the current limiting module 140 can also be composed of a second transistor JFET30 and a third diode Ge11. When the external power supply is turned on, the second transistor JFET30 is in a semi-conducting state, the third diode Ge11 is fully conducting, and the second diode Ge10 is in a cutoff state. The resistance of the third diode Ge11 and the second transistor JFET30 is equivalent to a variable resistance, which increases with the increase of voltage, playing a voltage division role to ensure that the operating current of the electrochromic device 130 is within the allowable range and to provide overvoltage protection. When the external power supply is turned off, the third diode Ge11 is in a cutoff state, and the second transistor JFET30 is equivalent to a wire formed by the source (S) and drain (D). After being connected in parallel with the second diode Ge10, the resistance is further reduced.

[0152] In some embodiments, such as Figure 8 As shown, the control terminal of the switch module 110 is connected to the second external power supply 150. The second external power supply 150 and the first external power supply 120 are switched on and off synchronously to control the switching of the switch module 110.

[0153] Specifically, in some embodiments, the number of external voltage groups can be two or more, wherein the first external power supply 120 provides the operating voltage for the electrochromic device 130, and the second external power supply 150 controls the opening and closing of the switch module 110.

[0154] In some embodiments, such as Figure 8 As shown, the switching module 110 includes a third transistor 111.

[0155] In this configuration, the source S of the third transistor 111 is connected to the first terminal of the first external power supply 120 and the first terminal of the second external power supply 150, the drain D of the third transistor 111 is connected to the first electrode of the electrochromic device 130 and the second terminal of the first external power supply 120, and the gate G of the third transistor 111 is connected to the second terminal of the second external power supply 150.

[0156] Specifically, the first external power supply 120 provides the operating voltage for the electrochromic device 130, and the second external power supply 150 controls the opening and closing of the switch module 110. When the first external power supply 120 and the second external power supply 150 are turned on simultaneously, the third transistor 111 is open-circuited; when the first external power supply 120 and the second external power supply 150 are turned off simultaneously, the second external power supply 150 and the third transistor 111 are in a fully conducting state. At this time, the first electrode and the second electrode of the electrochromic device 130 are short-circuited, and the electrochromic device discharges rapidly, returning to its initial state.

[0157] The electrochromic device and control method of the present invention will be described below through specific embodiments.

[0158] Example 1: In a glove box, the prepared sulfonate-modified polyacrylate was dissolved in dehydrated and deoxygenated propylene carbonate solvent and diluted to 5 wt%. 1,1-Dihexyl-4,4-bipyridine tetrafluoroborate (35 mmol / L) and 5,10-dihydrodimethylphenazine (35 mmol / L) were added to prepare the electrochromic electrolyte of this invention, which served as the electrochromic layer. The electrolyte was poured into the electrochromic device and sealed with UV adhesive. The device size was 26 cm x 7 cm, and the sheet resistance of the first conductive layer was 16 Ω / cm. 2 The sheet resistance of the second conductive layer is 2Ω / cm 2 The device edges are connected using conductive silver paste to form the circuit, thus obtaining the present invention. Figure 2 The large-size electrochromic device shown.

[0159] Integrating such on the PCB board Figure 9 The circuit shown has an electrochromic device with an operating voltage of 0.8V-1.2V and a resistance of 9Ω when operating at 1.2V. The diode in the current limiting module has a turn-on voltage of 0.2V-0.3V and an on-resistance ≤20Ω (0V-0.6V). The current limiting resistor has a resistance of 25Ω. The external power supply voltage is 5V. The transistor is an N-type JFET, with an on-current ID ≤10mA and an on-resistance RSD ≥500Ω when the gate voltage VGS(off) = -5V; and an on-resistance RSD ≤5Ω when the gate voltage VGS(on) ≥ -0.1V.

[0160] Test Method: Connect an external 5V DC power supply. Use a UV-Vis analyzer to measure the reflectance changes of the electrochromic device during energization and de-energization, recording the peak current and operating current of the external DC power supply, and calculating the power consumption. Place the electrochromic device in a -30℃ test chamber, connect it to the aforementioned PCB board, and perform a cyclic power-on test with 30s on and 30s off cycles. Observe the device status every 24 hours until a large area of ​​color residue appears on the device, and record the test time.

[0161] Example 2: The difference from Example 1 is that the external power supply voltage is 12V; when the transistor VGS(off)=-12V, ID≤0.2mA, RSD≥60kΩ; when VGS(on)≥-0.1V, RSD≤5Ω; the current limiting resistor value is 83Ω.

[0162] Example 3: The difference from Example 1 is that the external power supply voltage is 3V; when the transistor VGS(off) = -3V, ID≤20mA, RSD≥150Ω; when VGS(on)≥-0.1V, RSD≤5Ω; the current limiting resistor value is 14Ω.

[0163] Example 4: The difference from Example 1 is that the external power supply voltage is 1.2V; when the transistor VGS(off) = -1.2V, ID ≤ 25mA, RSD ≥ 50Ω; when VGS(on) ≥ -0.1V, RSD ≤ 8Ω; the current limiting resistor value is 0Ω.

[0164] Example 5: The difference from Example 1 is that the external power supply voltage is 1.2V; when the transistor VGS(off) = -1.2V, ID ≤ 10mA, RSD ≥ 120Ω; when VGS(on) ≥ -0.1V, RSD ≤ 15Ω; and the current limiting resistor has a resistance of 0Ω.

[0165] Example 6: The difference from Example 1 is that the transistor is replaced with a solid-state relay. When the external power supply is turned on, the relay's on-resistance is 600Ω, and when the external power supply is turned off, the relay's on-resistance is 12-30Ω.

[0166] Example 7: The difference from Example 1 is that the external power supply consists of two sets, as shown in the circuit diagram below. Figure 8 As shown.

[0167] The first external power supply is 1.2V, providing the operating voltage for the electrochromic device; the second external power supply is 12V, serving as the independent control power supply for the transistor. When both the first and second external power supplies are turned on, VGS(off) = -12V, ID ≤ 0.2mA, RSD ≥ 60kΩ, and the current-limiting resistor is 0Ω. When both the first and second external power supplies are turned off simultaneously, the second external power supply is open-circuited, and the transistor is in a fully conducting state, with its on-resistance RSD ≤ 5Ω. At this time, the current flows through the first electrode, the current-limiting resistor, and the transistor, and the short-circuit resistance can reach its minimum value.

[0168] Comparative Example 1: The difference from Example 1 is that the first and second electrodes of the electrochromic device are directly connected to an external power supply and controlled by a 1.2V DC power supply.

[0169] All test results are shown in Table 5:

[0170] Table 5 Comparison of Experimental Results

[0171]

[0172]

[0173] Compared with Comparative Example 1, Examples 1-7 show that the power control module of the present invention can significantly shorten the fading time of the electrochromic device from 13s to less than 3s; the delamination phenomenon at -30℃ is greatly improved.

[0174] Compared with Example 5, the higher the voltage of the external power supply in Examples 1-4, the higher the overall energy consumption, and the higher the performance of the transistors is required to reduce energy consumption.

[0175] Compared with Example 7, Example 2 uses two sets of external power supplies, which requires less energy and has lower requirements for transistor performance, but the circuit is more complex and the requirements for external power supplies are also higher.

[0176] For example, in this embodiment of the invention, an external power supply applies a first voltage to the control circuit of the electrochromic device, and the control circuit of the electrochromic device applies a second voltage to the electrochromic material to color the electrochromic material; after the external power supply is disconnected, the control circuit of the electrochromic device automatically short-circuits the first electrode and the second electrode of the electrochromic device to achieve rapid fading; wherein, the first voltage is 1.2V-12V, and the second voltage is 0.8V-1.2V.

[0177] The electrochromic material is an organic electrochromic material, and the operating voltage of the electrochromic device can be 0.8V-1.5V or higher. The control circuit of the electrochromic device requires ≤2 external power supply groups, and one independent power supply can also achieve automatic control. The control circuit of the electrochromic device consists of at least a transistor, a diode, and a current-limiting resistor, and can also consist of a relay, a diode, and a current-limiting resistor. The component specifications in the control circuit of the electrochromic device can be adjusted accordingly.

[0178] Compared with existing technologies, the control circuit of the electrochromic device of the present invention can achieve rapid coloring upon power-on and automatic short-circuiting upon power-off using only one external DC power supply, with only transistors, diodes and current-limiting resistors. It eliminates the need for processors or control chips, greatly reducing the design difficulty and manufacturing cost of the electrochromic device control circuit, and significantly reducing overall energy consumption. Large-size devices can also achieve rapid automatic discharge and complete fading within 3 seconds, greatly improving the device response rate and improving the layering phenomenon of liquid devices.

[0179] A second aspect of the present invention provides a rearview mirror system, such as Figure 10As shown, the rearview mirror system 200 includes an electrochromic device 130 and a control circuit 100 for the electrochromic device.

[0180] The control circuit 100 is connected to the electrochromic device 130.

[0181] According to an embodiment of the present invention, when the first external power supply is disconnected, the control switch module is turned on, causing the first electrode and the second electrode of the electrochromic device to be short-circuited, thereby realizing automated short-circuit control, increasing the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading. This allows the rearview mirror to make corresponding adjustments quickly under different ambient light intensities, preventing driver dizziness. Furthermore, the circuit does not require a processor or control unit, has a simple structure, reliable circuit connection, and low cost and power consumption.

[0182] A third aspect of the present invention provides a vehicle, such as Figure 11 As shown, vehicle 300 includes: a rearview mirror system 200.

[0183] According to an embodiment of the present invention, in the rearview mirror system, when the first external power supply is disconnected, the control switch module is turned on, causing the first electrode and the second electrode of the electrochromic device to be short-circuited, thereby realizing automated short-circuit control, increasing the discharge speed of the electrochromic device, and thus enabling the electrochromic device to achieve rapid fading, allowing the rearview mirror to make corresponding adjustments quickly under different ambient light intensities, and preventing driver dizziness.

[0184] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0185] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A control circuit for an electrochromic device, characterized by The switch module includes: a first end of the switch module is connected with a first end of a first external power supply for powering an electrochromic device, a second end of the switch module is connected with a second end of the first external power supply and a first electrode of the electrochromic device, and the switch module is used to automatically turn on in response to the first external power supply being disconnected to short-circuit the first electrode of the electrochromic device and a second electrode of the electrochromic device.

2. The control circuit of claim 1, wherein, When the first external power supply is disconnected, the switch module satisfies: wherein Rswitch module resistance 1 is a resistance of the switch module when the switch module is turned on, Uelectrochromic device voltage is a voltage of the electrochromic device when the switch module is turned on, and Iswitch module current is a current flowing through the switch module when the switch module is turned on.

3. The control circuit of claim 1, wherein, The switch module is also used to be in a disconnected state when the first external power supply is turned on, so that the first external power supply powers the electrochromic device.

4. The control circuit of claim 3, wherein, When the first external power supply is turned on, the switch module satisfies: wherein Rswitch module resistance 2 is a resistance of the switch module when the switch module is disconnected, Uelectrochromic device voltage is a voltage of the electrochromic device when the switch module is disconnected, and Ielectrochromic device current is a current of the electrochromic device when the switch module is disconnected.

5. The control circuit according to any one of claims 1 to 4, characterized in that, The switch module includes: a first triode, a source of the first triode is connected with a first end of the first external power supply and a second electrode of the electrochromic device, a drain of the first triode is connected with a first electrode of the electrochromic device and a second end of the first external power supply, and a gate of the first triode is connected with the drain of the first triode, the first electrode of the electrochromic device, and the second end of the first external power supply.

6. The control circuit of claim 5, wherein, The first triode includes a junction field effect transistor.

7. The control circuit of claim 6, wherein, The switch module further includes: a first diode, a gate of the junction field effect transistor is connected with the first electrode of the electrochromic device and the second end of the first external power supply through the first diode, an anode of the first diode is connected with the gate of the junction field effect transistor, and a cathode of the first diode is connected with the first electrode of the electrochromic device and the second end of the first external power supply, for controlling on-off of the junction field effect transistor.

8. The control circuit of claim 7, wherein, The first diode is a silicon diode.

9. The control circuit according to any one of claims 1 to 4, characterized in that The switch module includes: a normally closed relay, a first end of the normally closed relay is connected with the first end of the first external power supply and the second electrode of the electrochromic device, a second end of the normally closed relay is connected with the first electrode of the electrochromic device and the second end of the first external power supply, and a third end of the normally closed relay is connected with the second end of the normally closed relay, the first electrode of the electrochromic device, and the second end of the first external power supply.

10. The control circuit of claim 3, wherein, The control circuit further includes: a current limiting module, a first end of the current limiting module is connected with the first end of the switch module and the first end of the first external power supply, and a second end of the current limiting module is connected with the second electrode of the electrochromic device, for limiting voltage input to the electrochromic device.

11. The control circuit of claim 10, wherein, When the first external power supply is disconnected, the current-limiting module satisfies: R equivalent resistance = R current-limiting resistance + R electrochromic device resistance; Wherein, U electrochromic device voltage is the voltage of the electrochromic device when the switch module is turned on, R equivalent resistance is the equivalent resistance of the control circuit when the switch module is turned on, I discharge current is the discharge current of the electrochromic device, R current-limiting resistance is the resistance of the current-limiting module, and R electrochromic device resistance is the resistance of the electrochromic device.

12. The control circuit of claim 10, wherein, When the first external power supply is connected, the current-limiting module satisfies: Wherein, U first external power supply voltage is the voltage of the first external power supply, U electrochromic device voltage is the voltage of the electrochromic device when the switch module is disconnected, R current-limiting resistance is the resistance of the current-limiting module, R electrochromic device resistance is the resistance of the electrochromic device, and I first external power supply current is the connection current of the first external power supply.

13. The control circuit according to any one of claims 10-12, characterized by The current-limiting module comprises: A reverse flow prevention unit, a first end of the reverse flow prevention unit being connected with a first end of the switch module and a first end of the first external power supply, and a second end of the reverse flow prevention unit being connected with a second electrode of the electrochromic device, for preventing reverse input or output of the electrochromic device.

14. The control circuit of claim 13, wherein, The current-limiting module further comprises: A voltage stabilizing unit, a first end of the voltage stabilizing unit being connected with a first end of the switch module and a first end of the first external power supply, and a second end of the voltage stabilizing unit being connected with a second electrode of the electrochromic device and a second end of the reverse flow prevention unit, for voltage stabilization.

15. The control circuit of claim 14, wherein, The reverse flow prevention unit comprises: A second diode, a cathode of the second diode being connected with a first end of the switch module and a first end of the first external power supply, and an anode of the second diode being connected with a second electrode of the electrochromic device.

16. The control circuit of claim 15, wherein, The voltage stabilizing unit comprises: A fixed value resistor, a first end of the fixed value resistor being connected with a first end of the switch module and a first end of the first external power supply, and a second end of the fixed value resistor being connected with a second electrode of the electrochromic device and a second end of the reverse flow prevention unit.

17. The control circuit of claim 16, wherein, When the first external power supply is disconnected, the second diode and the fixed value resistor satisfy: Wherein, U electrochromic device voltage is the voltage of the electrochromic device, R second diode on-resistance is the on-resistance of the second diode, R fixed value resistance is the resistance value of the fixed value resistor, and I discharge current is the discharge current of the electrochromic device.

18. The control circuit of claim 16, wherein, When the first external power supply is connected, the second diode and the fixed value resistor satisfy: Wherein, U first external power supply voltage is the voltage of the first external power supply, U electrochromic device voltage is the voltage of the electrochromic device, R second diode off-resistance is the resistance when the second diode is off, R fixed value resistance is the resistance value of the fixed value resistor, and I first external power supply current is the current when the first external power supply is connected.

19. The control circuit of claim 15, wherein, The voltage stabilizing unit comprises: a second triode, a source of the second triode is connected with a first end of the switch module and a first end of the first external power supply, a drain of the second triode is connected with a second electrode of the electrochromic device and an anode of the second diode; a third diode, an anode of the third diode is connected with a gate of the second triode, a cathode of the third diode is connected with the second electrode of the electrochromic device and the anode of the second diode.

20. The control circuit of claim 1 or 3 or 10, wherein, a control end of the switch module is connected with a second external power supply, the second external power supply is synchronously turned on and turned off with the first external power supply to control the switch module to be turned on and turned off.

21. The control circuit of claim 20, wherein, the switch module comprises: a third triode, a source of the third triode is connected with a first end of the first external power supply and a first end of the second external power supply, a drain of the third triode is connected with a first electrode of the electrochromic device and a second end of the first external power supply, a gate of the third triode is connected with a second end of the second external power supply.

22. A rearview mirror system characterized by, a control circuit comprising the electrochromic device and the electrochromic device of any one of claims 1-21, the control circuit is connected with the electrochromic device.

23. A vehicle characterized by comprising: a rearview mirror system comprising the rearview mirror system of claim 22.

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