Overheat protection method for a charging connection assembly

Abstract

The application provides a kind of overheat protection method for charging connection assembly, charging connection assembly includes terminal and wire harness, terminal includes axially opposite plug end and connecting end, connecting end is connected with wire harness, method includes the following steps: S1: determining first monitoring position and second monitoring position on terminal, first monitoring position is at a first distance from plug end in axial direction, second monitoring position is at a second distance from plug end in axial direction, first distance is less than second distance;S2: synchronously collecting first temperature value and second temperature value at first monitoring position and second monitoring position respectively, and synchronously collecting current value of charging connection assembly;S3: calculating the thermal resistance of terminal according to first temperature value, second temperature value and current value of charging connection assembly;S4: determine whether the thermal resistance meets the preset protection condition, reduce or cut off the charging current of charging connection assembly according to the judgment result.

Description

Technical Field

[0001] This application relates primarily to the field of charging guns, and more particularly to an overheat protection method for charging connection components. Background Technology

[0002] With the rapid development of the new energy industry, the charging gun, as the core physical interface connecting the power battery and the charging pile, directly affects charging safety due to the contact performance of its internal terminals. Terminals are susceptible to overheating and even burning accidents due to multiple factors, including plating aging, crimping failures, increased mechanical tolerances from prolonged insertion and removal, and improper user operation. Therefore, timely overheat protection technology has become a key research focus.

[0003] Current mainstream overheat protection solutions typically only incorporate a single temperature sensor within the charging gun, relying on a fixed threshold to determine the measured temperature. This approach has significant technical limitations. First, since charging guns operate outdoors, a single sensor is highly susceptible to interference from external wind cooling and natural convection. This prevents the sensor from effectively separating the actual heat source temperature at the contact point from environmental heat dissipation, leading to distorted temperature judgments. Second, using a fixed threshold to judge the temperature at a single point cannot fully adapt to the wide-ranging dynamic fluctuations in charging current during fast charging.

[0004] Based on the above problems, there is an urgent need for an overheat protection method for charging connection components to more accurately determine the actual working conditions of the internal terminals of the charging gun, thereby avoiding the burning of the charging gun. Summary of the Invention

[0005] To address the aforementioned issues, this application proposes an overheat protection method for charging connection components, aiming to improve the accuracy and timeliness of the overheat protection method.

[0006] In a first aspect, this application proposes an overheat protection method for a charging connection assembly, the charging connection assembly including terminals and a wiring harness, the terminals including a plug end and a connecting end opposite each other along the axial direction, the connecting end being connected to the wiring harness, the method including the following steps: S1: determining a first monitoring position and a second monitoring position on the terminals, the first monitoring position being a first distance along the axial direction from the plug end, the second monitoring position being a second distance along the axial direction from the plug end, the first distance being less than the second distance; S2: synchronously acquiring a first temperature value and a second temperature value at the first monitoring position and the second monitoring position, respectively, and synchronously acquiring a current value of the charging connection assembly; S3: calculating the thermal resistance of the terminals based on the first temperature value, the second temperature value, and the current value of the charging connection assembly; S4: determining whether the thermal resistance meets a preset protection condition, and reducing or cutting off the charging current of the charging connection assembly based on the determination result.

[0007] Secondly, this application also proposes an overheat protection system for a charging connection assembly, the charging connection assembly including terminals and a wiring harness, the terminals including a plug end and a connecting end opposite each other along the axial direction, the connecting end being connected to the wiring harness, comprising: a first temperature sensor disposed at a first monitoring position of the terminal and configured to collect a first temperature value at the first monitoring position; a second temperature sensor disposed at a second monitoring position of the terminal and configured to collect a second temperature value at the second monitoring position, wherein the first monitoring position is axially a first distance from the plug end, the second monitoring position is axially a second distance from the plug end, and the first distance is less than the second distance; a current sensor configured to collect a current value of the charging connection assembly; and a processor configured to: calculate the thermal resistance of the terminal based on the first temperature value, the second temperature value, and the current value of the charging connection assembly; determine whether the thermal resistance meets a preset protection condition, and control the charging current of the charging connection assembly to be reduced or cut off based on the determination result.

[0008] Thirdly, this application also proposes a charging gun, including an overheat protection system for the charging connection assembly as described in the second aspect.

[0009] Compared with the prior art, the beneficial effects of this application are as follows: (1) This application constructs a spatial temperature difference at two terminal points and calculates the thermal resistance based on the current as the basis for overheat protection, effectively eliminating environmental heat dissipation interference, avoiding temperature criterion distortion caused by external airflow, and greatly improving the accuracy of operating condition monitoring.

[0010] (2) This application combines preset differentiated protection conditions to realize graded control for different abnormal operating conditions. It can perform current reduction buffering in the early stage of contact degradation and implement emergency power cut-off in case of serious fault, effectively balancing the operational stability and system safety of the charging process. Attached Figure Description

[0011] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings: Figure 1 This is a schematic diagram of the charging gun structure provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the charging connection component provided in the embodiments of this application; Figure 3 This is a schematic flowchart of an overheat protection method for a charging connection component provided in an embodiment of this application; Figure 4This is a flowchart illustrating the thermal resistance calculation method for an overheat protection method for a charging connection component provided in an embodiment of this application. Figure 5 This is a schematic flowchart of the temperature compensation calculation method for the overheat protection method for a charging connection component provided in the embodiments of this application; Figure 6 This is a schematic diagram of the overheat protection system for a charging connection component provided in an embodiment of this application.

[0012] Reference numerals: charging gun 100, charging connection assembly 200, terminal 210, plug end 211, connection end 212, wire harness 220, first temperature sensor 230, second temperature sensor 240, current sensor 250, processor 260, first monitoring position 270, second monitoring position 280. Detailed Implementation

[0013] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0014] As indicated in this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0015] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0016] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0017] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0018] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0019] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0020] The overheat protection method for the charging connection component of this application will be described below through specific embodiments.

[0021] As the core physical interface connecting the power battery and the charging pile, the contact performance of the charging connection component 200 directly affects charging safety. (Reference) Figure 1 and Figure 2 The charging gun 100 includes a charging connection assembly 200, which includes terminals 210 and a wiring harness 220. Terminal 210 includes a plug end 211 and a connecting end 212 that are axially opposed, and the connecting end 212 is connected to the wiring harness 220. In practical applications, the terminals 210 are highly susceptible to burning due to factors such as plating aging, poor contact at the crimp joint, or prolonged plugging and unplugging.

[0022] Traditional overheat protection designs often employ a single-point temperature sensor placement inside the charging gun 100, with overheat protection based on a fixed temperature threshold. However, this approach has significant drawbacks in actual operating conditions. Specifically, the terminals in the charging connection assembly 200 are often exposed to complex outdoor environments, making the temperature measured by a single sensor susceptible to external environmental influences; furthermore, the judgment logic based on a fixed threshold is ill-suited to operating scenarios with significant temperature fluctuations.

[0023] To address the aforementioned problems, this application proposes an overheat protection method for a charging connection assembly 200. This method involves axially spaced first temperature sensors 230 and second temperature sensors 240 on the terminal 210 to collect temperature values ​​at different locations; simultaneously, it acquires the current value of the charging connection assembly 200. Based on the collected temperature and current values, the internal thermal resistance of the terminal 210 is calculated; and the calculated thermal resistance is judged based on preset protection conditions; when the thermal resistance meets the preset protection conditions, a protection action of reducing or cutting off the charging current is executed. This application can effectively identify the deterioration trend of the contact performance of the terminal 210 and achieve active overheat protection.

[0024] refer to Figure 3 The overheat protection method for the charging connection assembly 200 proposed in this application includes... Figure 3 Steps S1 to S4 in the process.

[0025] In step S1, refer to Figure 2 A first monitoring position 270 and a second monitoring position 280 are determined on terminal 210. The first monitoring position is a first distance along the axial direction from the plug end 211, and the second monitoring position is a second distance along the axial direction from the plug end 211. The first distance is less than the second distance.

[0026] Specifically, along the axial direction of terminal 210, a first monitoring position 270 and a second monitoring position 280 are sequentially and spaced apart. These two monitoring points are distributed at different positions along the axial direction of terminal 210 and are used to collect the temperature values ​​of the first monitoring position 270 and the second monitoring position 280, respectively. The first monitoring position 270 is axially spaced from the plug end 211 by a first distance. The second monitoring position 280 is axially distanced from the plug end 211, representing the second distance. , where the first distance Less than the second distance Through the first distance With the second distance The distance between them is used to create an effective temperature difference.

[0027] In some embodiments, the first monitoring position is defined as being near the plug end 211, while the second monitoring position is defined as being at the connection end 212 where the wire harness 220 and the terminal 210 connect. This location is a stress concentration area at the crimping point of the wire harness 220 and the terminal 210. This allows the first monitoring position to detect temperature fluctuations caused by poor contact due to plating wear and mechanical deformation of the terminal 210 caused by high-frequency insertion and removal. The second monitoring position can detect temperature fluctuations caused by crimping process defects at the crimping point or loosening of the wire harness 220 due to external pulling. This significantly improves the ability to identify faults in different parts of the terminal 210.

[0028] In step S2, the first temperature value and the second temperature value are collected simultaneously at the first monitoring position and the second monitoring position, respectively, and the current value of the charging connection component 200 is collected simultaneously.

[0029] Specifically, the first temperature value was collected at the first monitoring location 270. The second temperature value was simultaneously collected at the second monitoring location 280. Simultaneously, the current value I in the charging connection component 200 is collected. The aforementioned first temperature value... Second temperature value The current value I in the charging connection component 200 can be continuously collected according to a preset collection period to achieve periodic and dynamic monitoring of the contact status of the terminal 210.

[0030] In step S3, the thermal resistance of terminal 210 is calculated based on the first temperature value, the second temperature value, and the current value of the charging connection component 200.

[0031] Specifically, the thermal resistance of terminal 210 is calculated based on the real-time measured first temperature value, second temperature value, and current value I of charging connection component 200, so as to reduce or cut off the charging current of charging connection component 200 according to the value of thermal resistance.

[0032] In some embodiments, reference Figure 4 , Figure 4 This includes steps S31 to S33 in step S3.

[0033] In step S31, refer to Figure 2 Calculate the temperature difference between the first temperature value and the second temperature value.

[0034] Specifically, in obtaining the first temperature value Second temperature value Next, calculate the first temperature value. With the second temperature value The difference.

[0035] In step S32, the Joule heat power is calculated based on the current value of the charging connection component 200 and the contact resistance of the terminal 210.

[0036] Specifically, the contact resistance of terminal 210 can be obtained from the factory markings on the charging gun or by testing the charging gun. Based on the current value I of the charging connection component 200 and the contact resistance of terminal 210, the Joule heat power can be calculated using the following formula (1).

[0037] (1)

[0038] Where P is the Joule thermal power, This represents the contact resistance of terminal 210. Joule thermal power indicates the rate at which heat is generated at terminal 210 under ideal conditions per unit time.

[0039] In step S33, the thermal resistance is calculated based on the temperature difference and Joule thermal power.

[0040] Specifically, based on the obtained first temperature value With the second temperature value The difference between the two values, and the Joule thermal power P, can be used to calculate the thermal resistance of terminal 210 using the following formula (2).

[0041] (2)

[0042] in, The thermal resistance of terminal 210 is thus calculated by creating a temperature difference at two points on terminal 210 and combining it with the current to effectively eliminate environmental interference with temperature, avoid temperature distortion caused by external airflow, and significantly improve the accuracy of temperature monitoring of charging gun 100.

[0043] In some embodiments, reference Figure 5After step S31 and before step S32, there is also step S34, which includes steps S34a to S34c.

[0044] In step S34a, refer to Figure 2 Within the acquisition period, the periodic temperature difference between the first temperature value at the current acquisition time and the first temperature value at the previous acquisition time is calculated, and the rate of change of the first temperature value is calculated based on the periodic temperature difference and the acquisition period.

[0045] Specifically, when the charging current experiences a transient surge, the calculated temperature difference shows a significant, step-like spike. This spike is not due to actual physical degradation of terminal 210, and without correction, it would lead to misjudgment. Therefore, a temperature difference compensation method is used to correct the temperature difference.

[0046] Within the acquisition period, the first temperature value collected by the first temperature sensor 230 at the current acquisition time is obtained, and the first temperature value at the previous acquisition time is compared with the first temperature value at the previous acquisition time. The periodic temperature difference between the two is calculated, and the rate of change of the first temperature value at the current time and the previous time is calculated based on the periodic temperature difference and the acquisition period.

[0047] Continue to refer to Figure 2 and Figure 5 In step S34b, if the rate of change of the first temperature value is greater than the preset sudden change threshold, the compensation temperature difference is calculated based on the rate of change of the first temperature value and the preset heat capacity coefficient of the terminal 210.

[0048] Specifically, the rate of change of the first temperature value is compared with a preset abrupt change threshold. If the rate of change of the first temperature value is greater than the preset abrupt change threshold, it indicates that a large transient step change has occurred in the temperature at the current moment. Therefore, the compensation temperature difference is calculated based on the rate of change of the first temperature value and the preset heat capacity coefficient of terminal 210.

[0049] In step S34c, the temperature difference is corrected using a compensated temperature difference, and the corrected temperature difference is used as the temperature difference value.

[0050] Specifically, the calculated temperature difference is subtracted from the compensated temperature difference to eliminate errors caused by transient temperature jumps. In this way, by constructing a compensated temperature difference to dynamically correct the temperature difference, false temperature differences caused by transient current jumps during charging can be effectively eliminated. This ensures that current reduction or power cut-off is only triggered when irreversible degradation occurs at terminal 210 (such as severe plating wear or loose crimping), greatly improving the stability of the charging process and the user experience.

[0051] Continue to refer to Figure 3 In step S4, it is determined whether the thermal resistance meets the preset protection conditions, and the charging current of the charging connection component 200 is reduced or cut off according to the determination result.

[0052] For details, please refer to Figure 2 The thermal resistance is compared with the preset protection conditions. Based on the judgment result, the current operating condition is identified, it is determined whether there is an abnormal deterioration trend in terminal 210, and then specific protection actions are executed.

[0053] In some embodiments, the preset protection conditions include: if the thermal resistance is less than a first basic thermal resistance, the current state is maintained; if the thermal resistance is greater than or equal to the first basic thermal resistance and less than a third basic thermal resistance, the current value of the charging connection component 200 is reduced by a preset current reduction margin; if the thermal resistance is greater than or equal to the third basic thermal resistance, the charging current of the charging connection component 200 is cut off and a fault is reported. Specifically, the basic thermal resistance is a fixed constant value obtained by the operator's experience. The first basic thermal resistance is 1.5 times the basic thermal resistance. If the calculated thermal resistance is less than the first basic thermal resistance, it indicates that the temperature of the terminal 210 is normal, and the charging connection component 200 maintains its current charging state. The third basic thermal resistance is 5 times the basic thermal resistance. When it is determined that the current thermal resistance reaches the first basic thermal resistance but does not exceed the third basic thermal resistance, it is determined that the contact state of the terminal 210 has become abnormal, but has not yet reached the level of severe deterioration to the point of melting. At this time, the current value of the charging connection component 200 is reduced by a preset current reduction margin, wherein the preset current reduction margin is 40% of the current current. The system records the current operating conditions and continuously monitors the corrected temperature difference and thermal resistance trend. If the thermal resistance is less than the first basic thermal resistance after the current reduction operation, the reduced current is maintained. If the current thermal resistance reaches or exceeds the third basic thermal resistance, it indicates that the contact interface of terminal 210 has severely deteriorated. In this case, the charging current of the charging connection component 200 is forcibly cut off, and the current operating condition is classified as a safety fault event. The current thermal resistance value and real-time current are recorded, and fault alarms and diagnostic data are sent to the host computer or cloud management platform. In this way, differentiated response strategies are set for different degrees of deterioration. Current reduction buffering is implemented for mild deterioration, effectively avoiding the erroneous cutting off of the current of the charging gun 100.

[0054] In some embodiments, when the charging current of the charging connection component 200 is cut off, if the thermal resistance is less than the first basic thermal resistance, the charging connection component 200 is powered on again. Specifically, after the charging current of the charging connection component is cut off, the system continuously monitors the decay trend of the thermal resistance. Power is only allowed to be restored when the current thermal resistance value is lower than the first basic thermal resistance. This mechanism avoids repeated power-on oscillations caused by temporary cooling of the terminal 210 surface, ensures the safe restoration of power to the charging connection component 200, and extends the service life of the charging connection component 200.

[0055] In some embodiments, if the thermal resistance is greater than or equal to a first basic thermal resistance and less than a second basic thermal resistance, the current value of the charging connection component 200 is reduced by a preset first current reduction margin; if the thermal resistance is greater than or equal to a second basic thermal resistance and less than a third basic thermal resistance, the current value of the charging connection component 200 is reduced by a preset second current reduction margin, wherein the preset first current reduction margin is less than or equal to the preset second current reduction margin. Specifically, the second basic thermal resistance is three times the basic thermal resistance, the preset first current reduction margin can be a 30% reduction of the current, and the preset second current reduction margin can be a 50% reduction of the current. Thus, by adopting a multi-level differentiated current reduction strategy, different protection actions can be performed for different degrees of degradation of the terminal 210. In the case of mild thermal resistance abnormality, the temperature rise is quickly suppressed with a small reduction margin, while maintaining charging continuity to the greatest extent and reducing user complaints; in the case of severe thermal resistance abnormality, the heat source is significantly reduced with a large reduction margin, strongly suppressing the risk of thermal runaway. This graded mechanism effectively balances safety protection and charging experience.

[0056] This application also proposes an overheat protection system for the charging connection assembly 200, referenced to Figure 2 and Figure 6 The charging connection assembly 200 includes a terminal 210 and a wire harness 220. The terminal 210 includes a plug end 211 and a connection end 212 that are axially opposite each other. The connection end 212 is connected to the wire harness 220.

[0057] The overheat protection system of the charging connection assembly 200 includes a first temperature sensor 230, a second temperature sensor 240, a current sensor 250, and a processor 260. The first temperature sensor 230 is located at a first monitoring position 270 of the terminal 210 and configured to collect a first temperature value at the first monitoring position 270. The second temperature sensor 240 is located at a second monitoring position 280 of the terminal 210 and configured to collect a second temperature value at the second monitoring position 280. The first monitoring position 270 is axially located at a first distance from the plug end 211, and the second monitoring position 280 is axially located at a second distance from the plug end 211, the first distance being less than the second distance. The current sensor 250 is configured to collect the current value of the charging connection assembly 200.

[0058] It also includes a processor 260, which is configured to calculate the first temperature value, the second temperature value and the current value of the charging connection component 200 to obtain the thermal resistance of the terminal 210; determine whether the thermal resistance meets the preset protection conditions, and control the charging current of the charging connection component 200 to be reduced or cut off according to the determination result.

[0059] In some embodiments, the processor 260 is further configured to calculate the temperature difference between the first temperature value and the second temperature value; and to calculate the thermal resistance based on the temperature difference and the Joule thermal power of the charging connection component 200, wherein the Joule thermal power is calculated based on the current value of the charging connection component 200 and the contact resistance of the terminal 210.

[0060] In some embodiments, the processor 260 is further configured to calculate, within the acquisition period, the periodic temperature difference between the first temperature value at the current acquisition time and the first temperature value at the previous acquisition time, and calculate the rate of change of the first temperature value based on the periodic temperature difference and the acquisition period; if the rate of change of the first temperature value is greater than a preset abrupt change threshold, calculate a compensation temperature difference based on the rate of change of the first temperature value and the preset thermal capacity coefficient of the terminal 210; use the compensation temperature difference to correct the temperature difference, and use the corrected temperature difference as the temperature difference value.

[0061] In some embodiments, the processor 260 is further configured to maintain the current state if the thermal resistance is less than the first basic thermal resistance; reduce the current value of the charging connection component 200 by a preset first current reduction margin if the thermal resistance is greater than or equal to the first basic thermal resistance and less than the second basic thermal resistance; reduce the current value of the charging connection component 200 by a preset second current reduction margin if the thermal resistance is greater than or equal to the second basic thermal resistance and less than the third basic thermal resistance; cut off the charging current of the charging connection component 200 and report a fault if the thermal resistance is less than the first basic thermal resistance after the current of the charging connection component 200 is cut off; and restore the power supply to the charging connection component 200 when the thermal resistance is less than the first basic thermal resistance after the current of the charging connection component 200 is cut off.

[0062] In some embodiments, the projections of the first temperature sensor 230 and the second temperature sensor 240 onto the cross-section of the terminal 210 are offset circumferentially by a predetermined angle. Specifically, the first temperature sensor 230 and the second temperature sensor 240 are arranged in a staggered manner along the circumferential direction of the cross-section of the terminal 210, that is, offset circumferentially by a predetermined angle, which is greater than 30° and less than 180°. The first temperature sensor 230 and the second temperature sensor 240 are asymmetrically arranged on the outer peripheral surface of the terminal 210. This ensures that the two sensors are on different heat conduction paths on the terminal 210. This arrangement effectively prevents heat from the first monitoring position from being directly conducted to the second monitoring position through the metal substrate, eliminating the superimposed interference of heat conduction caused by the two sensors being in the same heat dissipation channel.

[0063] This application also proposes a charging gun 100, such as Figure 1 As shown. The charging gun 100 includes an overheat protection system for the charging connection assembly.

[0064] This application uses specific terms to describe embodiments of the application. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0065] It should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0066] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used to describe embodiments are sometimes modified by the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A method for overheat protection of a charging connection assembly, the charging connection assembly comprising terminals and a wiring harness, the terminals comprising a plug end and a connecting end opposite each other along an axial direction, the connecting end being connected to the wiring harness, characterized in that, The method includes the following steps: S1: Determine a first monitoring position and a second monitoring position on the terminal, wherein the first monitoring position is axially a first distance from the plug end, and the second monitoring position is axially a second distance from the plug end, wherein the first distance is less than the second distance; S2: Simultaneously collect the first temperature value and the second temperature value at the first monitoring position and the second monitoring position, respectively, and simultaneously collect the current value of the charging connection component; S3: Calculate the thermal resistance of the terminal based on the first temperature value, the second temperature value, and the current value of the charging connection component; S4: Determine whether the thermal resistance meets the preset protection conditions, and reduce or cut off the charging current of the charging connection component according to the determination result.

2. The overheat protection method for a charging connection assembly as described in claim 1, characterized in that, The preset protection conditions include: If the thermal resistance is less than the first basic thermal resistance, then maintain the current state; If the thermal resistance is greater than or equal to the first basic thermal resistance and less than the third basic thermal resistance, then the current value of the charging connection component is reduced by a preset current reduction range. If the thermal resistance is greater than or equal to the third basic thermal resistance, the charging current of the charging connection component is cut off and a fault is reported.

3. The overheat protection method for a charging connection component as described in claim 2, characterized in that, Also includes: If the thermal resistance is greater than or equal to the first basic thermal resistance and less than the second basic thermal resistance, then the current value of the charging connection component is reduced by a preset first current reduction amplitude. If the thermal resistance is greater than or equal to the second basic thermal resistance and less than the third basic thermal resistance, then the current value of the charging connection component is reduced by a preset second current reduction amplitude. Wherein, the second basic thermal resistance is less than the third basic thermal resistance, and the preset first current reduction amplitude is less than or equal to the preset second current reduction amplitude.

4. The overheat protection method for a charging connection assembly as described in claim 2, characterized in that, When the charging current of the charging connection component is cut off, if the thermal resistance is less than the first basic thermal resistance, the charging connection component is powered on again.

5. The overheat protection method for a charging connection assembly as described in claim 1, characterized in that, Step S3 includes the following steps: S31: Calculate the temperature difference between the first temperature value and the second temperature value; S32: Calculate the Joule thermal power based on the current value of the charging connection component and the contact resistance of the terminal; S33: Calculate the thermal resistance based on the temperature difference and the Joule thermal power.

6. The overheat protection method for a charging connection assembly as described in claim 5, characterized in that, After step S31 and before step S32, there is a step S34, which includes the following steps: S34a: Within the acquisition period, calculate the periodic temperature difference between the first temperature value at the current acquisition time and the first temperature value at the previous acquisition time, and calculate the rate of change of the first temperature value based on the periodic temperature difference and the acquisition period. S34b: If the rate of change of the first temperature value is greater than the preset sudden change threshold, then calculate the compensation temperature difference based on the rate of change of the first temperature value and the preset thermal capacity coefficient of the terminal. S34c: Use the compensated temperature difference to correct the temperature difference value, and use the corrected temperature difference value as the temperature difference value.

7. An overheat protection system for a charging connection assembly, the charging connection assembly comprising terminals and a wiring harness, the terminals comprising a plug end and a connecting end opposed along an axial direction, the connecting end being connected to the wiring harness, characterized in that, include: A first temperature sensor is disposed at a first monitoring position of the terminal and configured to collect a first temperature value at the first monitoring position; A second temperature sensor is disposed at a second monitoring position of the terminal and configured to collect a second temperature value at the second monitoring position, wherein the first monitoring position is axially a first distance from the plug end, the second monitoring position is axially a second distance from the plug end, and the first distance is less than the second distance; A current sensor is configured to acquire the current value of the charging connection component; The processor is configured as follows: The thermal resistance of the terminal is calculated based on the first temperature value, the second temperature value, and the current value of the charging connection component; it is determined whether the thermal resistance meets the preset protection conditions, and the charging current of the charging connection component is reduced or cut off according to the determination result.

8. The overheat protection system for a charging connection assembly as described in claim 7, characterized in that, The processor is also configured to: Calculate the temperature difference between the first temperature value and the second temperature value; The thermal resistance is calculated based on the temperature difference and the Joule thermal power, wherein the Joule thermal power is calculated based on the current value of the charging connection component and the contact resistance of the terminal.

9. The overheat protection system for a charging connection assembly as described in claim 8, characterized in that, The processor is also configured to: Within the acquisition period, the periodic temperature difference between the first temperature value at the current acquisition time and the first temperature value at the previous acquisition time is calculated, and the rate of change of the first temperature value is calculated based on the periodic temperature difference and the acquisition period. If the rate of change of the first temperature value is greater than the preset abrupt change threshold, then the compensation temperature difference is calculated based on the rate of change of the first temperature value and the preset thermal capacity coefficient of the terminal. The temperature difference is corrected using the compensated temperature difference, and the corrected temperature difference is used as the temperature difference value.

10. The overheat protection system for a charging connection assembly as described in claim 7, characterized in that, The processor is also configured to: If the thermal resistance is less than the first basic thermal resistance, then maintain the current state; If the thermal resistance is greater than or equal to the first basic thermal resistance and less than the second basic thermal resistance, then the current value of the charging connection component is reduced by a preset first current reduction amplitude. If the thermal resistance is greater than or equal to the second basic thermal resistance and less than the third basic thermal resistance, then the current value of the charging connection component is reduced by a preset second current reduction amplitude. If the thermal resistance is greater than or equal to the third basic thermal resistance, the charging current of the charging connection component is cut off and a fault is reported. When the charging current of the charging connection component is cut off, if the thermal resistance is less than the first basic thermal resistance, the charging connection component is powered on again.

11. The overheat protection system for a charging connection assembly as described in claim 7, characterized in that, The projections of the first temperature sensor and the second temperature sensor on the cross-section of the terminal are offset circumferentially by a predetermined angle.

12. A charging gun, characterized in that, Includes an overheat protection system for a charging connection assembly as described in any one of claims 7 to 11.

Images