Safety protection system and method for relay of battery pack and vehicle

Abstract

The invention provides a safety protection system and method for a relay of a battery pack and a vehicle. The relay is connected in series in a main loop of the battery pack and comprises a movable contact and a static contact, and the safety protection system comprises a pressure sensor which is arranged between the movable contact and the static contact so as to detect the pressure between the movable contact and the static contact; the circuit breaking device is connected in series in a main loop of the battery pack; and the control unit is coupled between the pressure sensor and the circuit breaking device and is configured to start the circuit breaking device in response to the fact that the detected pressure is smaller than a preset threshold value so as to cut off a main loop of the battery pack. The pressure sensor is used for detecting the pressure between the movable contact and the static contact of the relay, the change of the pressure can be detected in the early stage that the pressure of the movable contact and the static contact is gradually reduced or poor contact occurs, the contact state of the relay is predicted in advance, and a main loop of the battery pack is cut off before arc discharge. And the safety and the reliability of an electrical system of the battery pack are improved.

Description

Technical Field

[0001] This invention relates to the field of vehicles, and more particularly to the field of vehicle battery systems. More specifically, it relates to a safety protection system and method for a relay of a battery pack, a vehicle including the safety protection system or using the safety protection method, a control unit implementing the safety protection method, a computer-readable storage medium executing the safety protection method, and a computer program product implementing the safety protection method. Background Technology

[0002] With the rapid development of new energy vehicle technology, electric vehicles are increasingly being used in daily life. In the electrical systems of electric vehicles, especially in high-voltage, high-current applications of the battery pack, relays, as key components of circuit control, are directly related to vehicle safety in terms of stability and reliability. When faults such as overcurrent or short circuits occur in the circuit, these abnormalities rapidly generate large currents in the high-voltage circuit of the battery pack, leading to strong electromagnetic repulsion. This electromagnetic repulsion is sufficient to forcibly separate the moving and stationary contacts of the relay, causing air gaps between the contacts and resulting in arcing. Arcing is not only accompanied by extremely high discharge energy but may also cause localized high temperatures, ultimately leading to fire or explosion of the relay or even the entire electrical system, seriously threatening the safety of the vehicle and its users.

[0003] Currently, current detection is commonly used to monitor the aforementioned problems. Specifically, a current sensor is installed in the main circuit of the battery pack to continuously monitor the current value in the main circuit and compare it with a preset threshold. When the current exceeds the preset threshold multiple times consecutively, it is determined to be an overcurrent or short circuit, and corresponding protective measures are taken, such as cutting off the circuit and activating an alarm mechanism. However, this method can only detect one threshold. For example, if the preset threshold is 4000A, then a low current short circuit below 4000A will not be identified as a short circuit. In addition, the range of the current sensor is usually no more than 1500A. If the current exceeds 1500A, it will produce a large error and a long response time. Therefore, multiple consecutive measurements of the current exceeding the preset threshold are required to determine that an overcurrent or short circuit has occurred in the main circuit, making it impossible to take timely protective measures.

[0004] Therefore, a safety protection system is needed that can quickly disconnect the main circuit to protect the relay when an overcurrent or short circuit occurs in the main circuit of the battery pack. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and provide a safety protection system and corresponding safety protection method for a battery pack relay, so as to protect the relay in a cost-effective and reliable manner.

[0006] Therefore, according to one aspect of the present invention, a safety protection system for a relay of a battery pack is provided, the relay being connected in series in the main circuit of the battery pack and including a moving contact and a stationary contact, the safety protection system comprising: a pressure sensor disposed between the moving contact and the stationary contact to detect the pressure between the moving contact and the stationary contact; a circuit breaker device connected in series in the main circuit of the battery pack; and a control unit coupled between the pressure sensor and the circuit breaker device and configured to activate the circuit breaker device in response to the detected pressure being less than a preset threshold, thereby disconnecting the main circuit of the battery pack.

[0007] Based on the above-described technical concept, the present invention may further include any one or more of the following optional forms.

[0008] In some alternative configurations, the relay includes a main positive relay and a main negative relay, with the circuit breaker coupled between the main positive relay and the battery pack.

[0009] In some alternative configurations, the battery pack includes a battery management system, and the control unit is integrated with the battery management system.

[0010] In some alternative configurations, the battery pack includes a battery disconnect unit, and the safety protection system is integrated with the battery disconnect unit.

[0011] In some alternative forms, the control unit includes any of a microcontroller, a digital signal processor, or an application-specific integrated circuit, and / or the circuit breaker is configured as a blowout fuse or a DC circuit breaker, and / or the pressure sensor is configured as a varistor.

[0012] According to another aspect of the present invention, a safety protection method for a relay of a battery pack is provided, the relay being connected in series in the main circuit of the battery pack and including a moving contact and a stationary contact, the safety protection method comprising: detecting the pressure between the moving contact and the stationary contact; and disconnecting the main circuit of the battery pack in response to the detected pressure being less than a preset threshold.

[0013] According to another aspect of the present invention, a vehicle is provided that includes the above-described safety protection system for the relays of the battery pack, or the vehicle uses the above-described safety protection method for the relays of the battery pack to provide safety protection for the relays of the battery pack.

[0014] In some alternative forms, the vehicle includes a body controller that communicates with a control unit of the safety system, wherein the body controller is configured to send an alarm notification to a user via the vehicle's dashboard and / or infotainment system in response to a detected pressure being less than a preset threshold.

[0015] According to another aspect of the present invention, a control unit is provided, the control unit including a memory, a processor and instructions stored in the memory and executable by the processor, wherein the processor implements the above-described safety protection method for the relay of the battery pack when executing the instructions.

[0016] According to another aspect of the present invention, a computer-readable storage medium is provided having computer-executable instructions stored thereon for performing the above-described safety protection method for a relay of a battery pack.

[0017] According to another aspect of the present invention, a computer program product is provided, comprising computer-executable instructions that, when executed by at least one processor, implement the aforementioned safety protection method for the relay of the battery pack.

[0018] This invention uses a pressure sensor to detect the pressure between the moving and stationary contacts of a relay. It can detect pressure changes in the early stages when the pressure between the moving and stationary contacts gradually decreases or poor contact occurs, thus predicting the contact state of the relay in advance and cutting off the main circuit of the battery pack before arcing occurs. Furthermore, by detecting the physical state of the moving and stationary contacts, the operating state of the relay can be understood more intuitively, reducing the possibility of accidental disconnection of the main circuit and improving the reliability of the safety protection system. Attached Figure Description

[0019] Other features and advantages of the present invention will be better understood through the following detailed description of optional embodiments in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 A schematic diagram of a relay according to an embodiment of the present invention during normal operation is shown;

[0021] Figure 2 It shows Figure 1 A schematic diagram of the forces acting on the moving contact of a relay during a short circuit;

[0022] Figure 3 It shows Figure 1 A schematic diagram showing arcing in a relay;

[0023] Figure 4 A schematic diagram of a relay safety protection system for a battery pack according to an embodiment of the present invention is shown;

[0024] Figure 5 It shows Figure 4 Enlarged view of the relay in the image;

[0025] Figure 6A schematic diagram of the main circuit of a battery pack according to an embodiment of the present invention is shown;

[0026] Figure 7 A schematic flowchart of a safety protection method for a relay of a battery pack according to an embodiment of the present invention is shown;

[0027] Figure 8 A schematic diagram of a control unit according to one embodiment of the present invention is shown. Detailed Implementation

[0028] The implementation and use of the embodiments are discussed in detail below. While the exemplary systems described below include software and / or firmware executed on hardware among other components, it should be noted that these examples are merely illustrative and should not be considered limiting. Therefore, although exemplary systems have been described below, those skilled in the art will readily understand that the specific embodiments discussed are merely exemplary of particular ways of implementing and using the invention, and not intended to limit the scope of the invention.

[0029] Furthermore, the flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions, and operations of the methods and systems according to various embodiments of the present invention. It should be noted that the functions marked in the boxes may occur in a different order than that shown in the drawings. For example, two consecutively indicated boxes may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved.

[0030] like Figure 1 As shown, when the battery pack is operating normally, the moving contact 133 and the stationary contact 134 of the relay are engaged, allowing current to flow through the main circuit of the battery pack. When the battery pack experiences events such as thermal runaway, mechanical damage, or overcharging, the current in the battery pack will increase, potentially causing a short circuit. During a short circuit, a large current will flow through the main circuit of the battery pack, resulting in a very large electromagnetic force. This electromagnetic force will push the moving contact 133 of the relay along... Figure 2As shown in Figure A, the stationary contact 134 is moved away. Since the relay can only withstand large currents for a few milliseconds—for example, approximately 10 milliseconds for 6000A, approximately 5 milliseconds for 8000A, and approximately 1 millisecond for 10000A—the inventors discovered that current sensors used to detect overcurrent or short circuits require continuous detection of current exceeding a preset threshold. For example, to detect overcurrent, 20 consecutive detections of current exceeding 1000A are needed; to detect short circuits, 10 consecutive detections of current exceeding 4000A are needed. This detection method can take tens of milliseconds. During detection, the electromagnetic force continuously pushes the moving contact 133 of the relay away from the stationary contact 134. After the relay's ability to withstand large currents exceeds its limit, an electric arc will be generated between the moving contact 133 and the stationary contact 134, causing arcing. Figure 3 As shown, when the moving contact 133 of the relay moves away from the stationary contact 134, the electric arc B will cause the relay to catch fire or explode with extremely high energy.

[0031] Combination Figures 4 to 6 As shown, the safety protection system for the relay of a battery pack according to one embodiment of the present invention generally includes a pressure sensor 110, a circuit breaker 120, and a control unit 140. Figure 4 and Figure 6 In this configuration, a relay is connected in series in the main circuit of the battery pack 200, and a pressure sensor 110 is located between the moving contact 133 and the stationary contact 134 of the relay to detect the pressure between them. In some embodiments, the pressure sensor 110 can be a piezoresistive resistor, whose resistance changes with pressure. This change in resistance allows the detection of the pressure state between the relay contacts. Piezoresistive resistors have a simple structure, reducing installation time and simplifying the design of the safety protection system. It is understood that the pressure sensor 110 is not limited to this; any sensor suitable for detecting the pressure between the relay contacts is acceptable. Figure 6 As shown, the circuit breaker 120 is connected in series in the main circuit of the battery pack 200. The circuit breaker 120 can disconnect the main circuit of the battery pack 200 after activation to prevent the relay from catching fire or exploding. Figure 4 In this configuration, control unit 140 is coupled between pressure sensor 110 and circuit breaker 120. When pressure sensor 110 detects that the pressure between the moving contact 133 and stationary contact 134 of the relay is less than a preset threshold, control unit 140 activates circuit breaker 120 to disconnect the main circuit of the battery pack. In some embodiments, control unit 140 may include a microcontroller (MCU), digital signal processor (DSP), application-specific integrated circuit (ASIC), etc. In some embodiments, the preset pressure threshold may be in the range of 30N to 350N, for example, 50N. It is understood that the preset pressure threshold is not limited to this and may be changed according to the relay specifications.

[0032] In this manner, the safety protection system of the battery pack relay according to one embodiment of the present invention detects the pressure between the moving contact 133 and the stationary contact 134 of the relay using a pressure sensor 110. This allows for early detection of pressure changes in the early stages of gradually decreasing pressure or poor contact between the moving and stationary contacts, thus predicting the contact state in advance and cutting off the main circuit of the battery pack 200 before arcing occurs. Furthermore, since the moving and stationary contacts cannot return to their original state after arcing, detecting the physical state of the relay contacts eliminates the need for repeated detections, providing a more intuitive understanding of the relay's operating state, reducing the likelihood of accidental disconnection of the main circuit, and improving the reliability of the safety protection system.

[0033] like Figure 6 As shown, the relays in the battery pack 200 include a main positive relay 131 and a main negative relay 132. The main positive relay 131 and the main negative relay 132 are respectively connected to the positive and negative terminals of the battery pack 200 to control the connection between the positive and negative terminals of the battery pack 200 and the external circuit. In this embodiment, the circuit breaker 120 is coupled between the main positive relay 131 and the battery pack 200. Thus, in the event of an overcurrent or short-circuit fault, current can be prevented from flowing out of the positive terminal of the battery pack 200 first, effectively controlling the disconnection of the main circuit of the battery pack 200. Furthermore, since the positive terminal of the battery pack 200 has a higher voltage than the negative terminal, overcurrent or short circuits at the positive terminal are usually more dangerous. Placing the circuit breaker 120 near the positive terminal can interrupt the high-potential current at an earlier stage, avoiding more severe arcing and further improving the reliability of the safety protection system.

[0034] exist Figure 6 The safety protection system may also include a current sensor 150 to detect the current in the main circuit of the battery pack 200 in real time. It is understood that the safety protection system may also include other sensors such as voltage sensors and temperature sensors to detect the status of the battery pack 200 in real time. The battery management system (BMS) of the battery pack 200 can adjust the relevant parameters of the battery pack 200 according to the detected data to maintain the working performance of the battery pack 200.

[0035] In some embodiments, the circuit breaker 120 can be a pyro fuse or a DC circuit breaker. When activated, the pyro fuse ignites internal explosive fuel, which drives a piston device to move rapidly, cutting off the copper bar of the pyro fuse and thus disconnecting the main circuit of the battery pack 200. The copper bar refers to a flexible connector made of copper foil material used to connect the pyro fuse in series with the main circuit of the battery pack 200. The DC circuit breaker can be, for example, Eaton's Breaktor, a high-voltage circuit protection device for electric vehicles. This DC circuit breaker combines the functions of a circuit breaker and a fuse and employs hybrid switching technology to effectively suppress arcing and improve the reliability of the safety protection system.

[0036] In some implementations, the control unit 140 can be integrated with the battery management system of the battery pack 200 to obtain the pressure detected by the pressure sensor 110 and activate the circuit breaker 120. In this way, the triggering mechanism of the circuit breaker 120 can be integrated into the battery management scheme through the battery management system, enabling a comprehensive judgment on whether to activate the circuit breaker 120 based on multiple parameters such as current, voltage, and temperature, thus providing more precise safety protection for the relay.

[0037] Additionally, the battery pack 200 also includes a battery circuit breaker unit (BDU). In some embodiments, the safety protection system can be integrated with the battery circuit breaker unit to disconnect the main circuit of the battery pack 200. In this case, the battery management system and the battery circuit breaker unit can handle different voltage levels. For example, the battery management system can be responsible for the management and protection of the battery pack 200, primarily handling operations in the low-voltage range, such as monitoring each battery cell and low-voltage communication, which can be in the range of approximately 3.6V to 4.2V. The battery circuit breaker unit can be responsible for circuit protection and switching operations related to high voltage, such as controlling the switching operation of relays, detecting relay arcing or short circuits, etc., in the high-voltage range of approximately 400V to 800V. Thus, electrical isolation between the high and low voltage levels of the battery pack 200's electrical system can be achieved, improving the safety and reliability of the electrical system.

[0038] In some implementations, the control unit 140 of the safety protection system can communicate with the vehicle's body control unit (VCU). Thus, when the pressure sensor 110 detects that the pressure between the relay contacts is less than a preset threshold, the body control unit can send an alert notification to the user via the vehicle's dashboard and / or infotainment system. The user can then use this alert notification to notify a service center to inspect and repair the vehicle's battery pack and related electrical systems.

[0039] Reference Figure 7A safety protection method for a relay in a battery pack according to an embodiment of the present invention includes the following steps:

[0040] Step S1: Detect the pressure between the moving contact and the stationary contact of the relay.

[0041] Step S2: In response to the detected pressure being less than a preset threshold, disconnect the main circuit of the battery pack.

[0042] Please refer to the above text for the function of the safety protection method for the relay in the battery pack according to this embodiment. Figures 4 to 6 The content mentioned above will not be repeated here.

[0043] Reference Figure 8 , Figure 8 This is a schematic diagram of a control unit according to one embodiment of the present invention.

[0044] The present invention also provides a control unit, such as Figure 8 As shown, the control unit may include a memory 310 and a processor 320. The memory 310 may store instructions 311, which may be executed by the processor 320. When the processor 320 executes the instructions 311, it implements the safety protection method for the relay of the battery pack according to the above embodiment.

[0045] The control unit in this embodiment can be a device such as a laptop, desktop computer, or cloud server. It is understood that the components included in the control unit are not limited to the memory 310 and processor 320, and can vary depending on different needs. Exemplarily, the control unit may also include multiple components connected to its input / output interfaces (…). Figure 8 (Not shown in the image), including but not limited to: input units, such as keyboards, mice, etc.; output units, such as displays, speakers, etc.; storage units, such as semiconductor storage devices, magnetic surface storage devices, optical storage devices, etc.; and communication units, such as network interface cards, wireless communication transceivers, etc.

[0046] In some implementations, memory 310 may include, for example, random access memory (RAM) or read-only memory (ROM). Memory 310 may be used to store instructions, programs, code, and other programs and data required by the control unit, but is not limited thereto.

[0047] In addition, the processor 320 can be a central processing unit (CPU) or other general-purpose processors, such as digital signal processing (DSP), field-programmable gate array (FPGA), programmable logic array (PLA), etc.

[0048] In an exemplary embodiment of the present invention, a computer-readable storage medium is also provided having computer-executable instructions stored thereon for performing a safety protection method for a relay of a battery pack according to the above embodiments.

[0049] Alternatively, the computer-readable storage medium according to this embodiment may be a ROM, RAM, semiconductor storage device, magnetic surface storage device, and optical storage device, etc.

[0050] The present invention also proposes a computer program product comprising computer-executable instructions that, when executed, cause at least one processor to perform the safety protection method for the relay of the battery pack according to the above embodiments.

[0051] Generally, various embodiments of the present invention can be implemented in hardware, dedicated circuitry, software programs, firmware, logic circuitry, or any combination thereof, as needed. Specifically, some aspects may be implemented in hardware, while others may be implemented in firmware or software programs executable by a controller, microprocessor, or other computing device. When aspects of embodiments of the present invention are illustrated or described as block diagrams, flowcharts, or using some other graphical representation, it will be understood that the blocks, apparatuses, systems, techniques, or methods described herein can be implemented as non-limiting examples in hardware, software, firmware, dedicated circuitry, logic circuitry, general-purpose hardware, or controllers or other computing devices, or some combination thereof.

[0052] Computer-readable program instructions or computer program products for executing various embodiments of the present invention can also be stored in the cloud. When needed, users can access the computer-readable program instructions stored in the cloud for executing an embodiment of the present invention via mobile internet, fixed network or other networks, thereby implementing various embodiments of the present invention.

[0053] It should be understood that the embodiments shown in the figures only illustrate optional configurations of the safety protection system of the relay of the battery pack according to the present invention; however, they are merely illustrative and not limiting. Other configurations may be adopted without departing from the spirit and scope of the present invention.

[0054] The technical content and features of the present invention have been disclosed above. However, it is understood that those skilled in the art can make various changes and improvements to the disclosed concepts under the inventive concept of the present invention, all of which fall within the protection scope of the present invention. The description of the above embodiments is illustrative rather than restrictive, and the protection scope of the present invention is determined by the claims.

Claims

1. A safety protection system for a relay in a battery pack, wherein the relay (131, 132) is connected in series in the main circuit of the battery pack (200) and includes a moving contact (133) and a stationary contact (134), characterized in that, The security protection system includes: A pressure sensor (110) is disposed between the moving contact (133) and the stationary contact (134) to detect the pressure between the moving contact (133) and the stationary contact (134); A circuit breaker (120) is connected in series in the main circuit of the battery pack (200); A control unit (140) is coupled between the pressure sensor (110) and the circuit breaker (120) and configured to activate the circuit breaker (120) in response to the detected pressure being less than a preset threshold, thereby disconnecting the main circuit of the battery pack (200).

2. The security protection system according to claim 1, characterized in that, The relays (131, 132) include a main positive relay (131) and a main negative relay (132), and the circuit breaker (120) is coupled between the main positive relay (131) and the battery pack (200).

3. The security protection system according to claim 1 or 2, characterized in that, The battery pack (200) includes a battery management system, and the control unit (140) is integrated with the battery management system.

4. The security protection system according to claim 1 or 2, characterized in that, The battery pack (200) includes a battery circuit breaker unit, and the safety protection system is integrated with the battery circuit breaker unit.

5. The security protection system according to claim 1 or 2, characterized in that, The control unit (140) includes any of a microcontroller, a digital signal processor, and an application-specific integrated circuit, and / or the circuit breaker (120) is configured as a blown fuse or a DC circuit breaker, and / or the pressure sensor (110) is configured as a varistor.

6. A safety protection method for a relay in a battery pack, wherein the relay (131, 132) is connected in series in the main circuit of the battery pack (200) and includes a moving contact (133) and a stationary contact (134), characterized in that, The security protection method includes: Detect the pressure (S1) between the moving contact (133) and the stationary contact (134); In response to the detected pressure being less than a preset threshold, the main circuit of the battery pack (200) is cut off (S2).

7. A vehicle, characterized in that, The vehicle includes a safety protection system for the relays of the battery pack according to any one of claims 1 to 5, or the vehicle uses a safety protection method for the relays of the battery pack (200) according to claim 6 to provide safety protection for the relays (131, 132) of the battery pack (200).

8. The vehicle according to claim 7, characterized in that, The vehicle includes a body controller that communicates with a control unit (140) of the safety protection system, wherein the body controller is configured to send an alarm notification to a user via the vehicle's dashboard and / or infotainment system in response to a detected pressure being less than a preset threshold.

9. A control unit, characterized in that, The control unit includes a memory (310), a processor (320), and instructions (311) stored in the memory (310) and executable by the processor (320), wherein the processor (320) implements the safety protection method for the relay of the battery pack according to claim 6 when executing the instructions (311).

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium has computer-executable instructions stored thereon for performing the safety protection method for the relay of the battery pack according to claim 6.

11. A computer program product comprising computer-executable instructions, characterized in that, When the computer-executable instructions are executed by at least one processor, the safety protection method for the relay of the battery pack according to claim 6 is implemented.

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