Signal acquisition circuit of battery management system, vehicle high-voltage system and vehicle

Abstract

The application discloses a signal acquisition circuit of a battery management system, a high-voltage system of a vehicle and the vehicle, relates to the technical field of signal acquisition, and comprises a fusing and absorbing unit, a first end of the fusing and absorbing unit is connected with a positive electrode of a power battery, a second end of the fusing and absorbing unit is connected with a negative electrode of the power battery, and the fusing and absorbing unit is used for fusing and absorbing counter electromotive force and / or inrush current to obtain normal acquisition signals when the power battery outputs the counter electromotive force and / or the inrush current; an isolation filtering unit, a first end of the isolation filtering unit is connected with a second end of the fusing and absorbing unit, a second end of the isolation filtering unit is connected with a third end of the fusing and absorbing unit, a third end of the isolation filtering unit is connected with a positive electrode of a battery management system, a fourth end of the isolation filtering unit is connected with a negative electrode of the battery management system, and the isolation filtering unit is used for carrying out isolation filtering on the normal acquisition signals to obtain target acquisition signals, so that the signal acquisition of the battery management system is realized. The application prolongs the service life of the signal acquisition circuit of the battery management system.

Description

Technical Field

[0001] This application relates to the field of signal acquisition technology, and in particular to a signal acquisition circuit for a battery management system, a vehicle high-voltage system, and a vehicle. Background Technology

[0002] With the increasing use of signal acquisition circuits in battery management systems, users are also placing higher demands on the design of these circuits.

[0003] The traditional signal acquisition circuit design of a battery management system (BMS) acquires signals from the component to be acquired (such as a power battery) by sequentially connecting a voltage divider resistor and a sampling chip. This design has certain drawbacks. When the component to be acquired outputs extremely high back electromotive force (EMF) and / or surge current, the back EMF and / or surge current can damage the voltage divider resistor and the sampling chip. In other words, this design of the battery management system's signal acquisition circuit can lead to damage to the voltage divider resistor and the sampling chip due to back EMF and / or surge current, resulting in a short service life for the signal acquisition circuit. Utility Model Content

[0004] The main purpose of this application is to provide a signal acquisition circuit for a battery management system, a vehicle high-voltage system, and a vehicle, aiming to solve the technical problem of the short service life of the signal acquisition circuit for the battery management system.

[0005] To achieve the above objectives, this application provides a signal acquisition circuit for a battery management system, the signal acquisition circuit of which includes: A fuse and absorption unit is provided, wherein the first end of the fuse and absorption unit is connected to the positive terminal of the power battery, and the second end of the fuse and absorption unit is connected to the negative terminal of the power battery. The fuse and absorption unit is used to fuse and absorb the back electromotive force and / or the surge current when the power battery outputs back electromotive force and / or surge current to obtain a normal acquisition signal. An isolation filtering unit is provided, wherein a first end of the isolation filtering unit is connected to a second end of the fuse and absorption unit, a second end of the isolation filtering unit is connected to a third end of the fuse and absorption unit, a third end of the isolation filtering unit is connected to the positive terminal of the battery management system, and a fourth end of the isolation filtering unit is connected to the negative terminal of the battery management system. The isolation filtering unit is used to isolate and filter the normal acquisition signal to obtain the target acquisition signal, thereby realizing the signal acquisition of the battery management system.

[0006] In one embodiment, the fusing and absorbing unit includes: A fuse, the first end of which serves as the first end of the fusing and absorption unit and is connected to the positive terminal of the power battery; A varistor, wherein the first end of the varistor serves as the third end of the fuse and absorption unit, and is connected to the second end of the isolation filter unit and the second end of the fuse; the second end of the varistor serves as the second end of the fuse and absorption unit, and is connected to the negative terminal of the power battery and the first end of the isolation filter unit.

[0007] In one embodiment, the fusing and absorbing unit includes: A varistor, the first end of which serves as the first end of the fuse and absorption unit and is connected to the positive terminal of the power battery; A fuse, the first end of which serves as the third end of the fusing and absorption unit, is connected to the second end of the isolation filter unit and the second end of the varistor. The second end of the fuse serves as the second end of the fusing and absorption unit and is connected to the negative terminal of the power battery and the first end of the isolation filter unit.

[0008] In one embodiment, the isolation filtering unit includes: A common-mode inductor, wherein the first terminal of the common-mode inductor serves as the first terminal of the isolation filter unit and is connected to the second terminal of the fuse and absorption unit; the second terminal of the common-mode inductor serves as the second terminal of the isolation filter unit and is connected to the third terminal of the fuse and absorption unit; the third terminal of the common-mode inductor serves as the second terminal of the isolation filter unit and is connected to the positive terminal of the battery management system; and the fourth terminal of the common-mode inductor serves as the third terminal of the isolation filter unit and is connected to the negative terminal of the battery management system. A first capacitor, wherein a first terminal of the first capacitor is connected to a third terminal of the common-mode inductor and the positive terminal of the battery management system, and a second terminal of the first capacitor is connected to a fourth terminal of the common-mode inductor and the negative terminal of the battery management system. The second capacitor has its first terminal connected to the third terminal of the common-mode inductor and the positive terminal of the battery management system, and its second terminal connected to the fourth terminal of the common-mode inductor and the negative terminal of the battery management system.

[0009] In one embodiment, the common-mode inductor includes: The first inductor winding has a first end that serves as the first end of the common mode inductor and is connected to the second end of the fuse and absorption unit. The second end of the first inductor winding serves as the third end of the common mode inductor and is connected to the positive terminal of the battery management system. The second inductor winding has a first end that serves as the second end of the common-mode inductor and is connected to the third end of the fuse and absorption unit. The second end of the second inductor winding serves as the fourth end of the common-mode inductor and is connected to the negative terminal of the battery management system.

[0010] In one embodiment, the signal acquisition circuit of the battery management system further includes a protection switching unit, the protection switching unit comprising: The transistor has its first end connected to the second end of the fuse in the fusing and absorption unit, and its second end connected to the positive terminal of the power battery. A current comparator, wherein the first terminal of the current comparator is connected to the third terminal of the transistor, and the second terminal of the current comparator is connected to a comparison current source; A fuse switching subunit, wherein the first terminal of the fuse switching subunit is connected to the third terminal of the current comparator, the second terminal of the fuse switching subunit is connected to the first terminal of the fuse, and the third terminal of the fuse switching subunit is connected to the second terminal of the fuse.

[0011] In one embodiment, the fuse switching subunit includes: A replacement fuse is provided, wherein the second end of the replacement fuse is connected to the second end of the original fuse. The two-to-one selection device has a control terminal that serves as the first terminal of the fuse switching subunit and is connected to the third terminal of the current comparator. The input terminal of the two-to-one selection device serves as the second terminal of the fuse switching subunit and is connected to the first terminal of the fuse. The first output terminal of the two-to-one selection device serves as the third terminal of the fuse switching subunit and is connected to the first terminal of the replacement fuse. The second output terminal of the two-to-one selection device is left floating.

[0012] In addition, to achieve the above objectives, this application also provides a vehicle high-voltage system, which includes the signal acquisition circuit of the battery management system, the battery management system, the power battery, and the motor drive module described above. The first terminal of the signal acquisition circuit of the battery management system is connected to the positive and negative terminals of the power battery, and the second terminal of the signal acquisition circuit of the battery management system is connected to the positive and negative terminals of the battery management system. The first terminal of the motor drive module is connected to the positive and negative terminals of the power battery through a high-voltage DC bus. The back electromotive force and / or the surge current are generated by the motor drive module and transmitted to the power battery through the high-voltage DC bus.

[0013] In one embodiment, the motor drive module includes: Motor controller and motor; The motor drive circuit has a first terminal serving as the first terminal of the motor drive module and connected to the positive and negative terminals of the power battery. The second terminal of the motor drive circuit is connected to the motor controller, and the third terminal of the motor drive circuit is connected to the motor.

[0014] In addition, to achieve the above objectives, this application also provides a vehicle that includes the aforementioned vehicle high-voltage system.

[0015] This application provides a signal acquisition circuit for a battery management system. The signal acquisition circuit includes a fuse and absorption unit. The first terminal of the fuse and absorption unit is connected to the positive terminal of the power battery, and the second terminal is connected to the negative terminal of the power battery. The fuse and absorption unit is used to fuse and absorb the back electromotive force and / or surge current when the power battery outputs back electromotive force and / or surge current to obtain a normal acquisition signal. An isolation filtering unit is also provided. The first terminal of the isolation filtering unit is connected to the second terminal of the fuse and absorption unit, the second terminal is connected to the third terminal of the fuse and absorption unit, the third terminal is connected to the positive terminal of the battery management system, and the fourth terminal is connected to the negative terminal of the battery management system. The isolation filtering unit is used to isolate and filter the normal acquisition signal to obtain the target acquisition signal, thereby realizing the battery management system... The signal acquisition circuit of this battery management system can use fuses and absorption units to melt and absorb the back EMF and / or surge current when the power battery outputs back EMF and / or surge current, thus obtaining a normal acquisition signal. Simultaneously, the normal acquisition signal is further isolated and filtered to obtain the target acquisition signal. In other words, the fuse and absorption units and isolation filtering units eliminate the influence of back EMF and / or surge current on the battery management system (such as damage to the voltage divider resistors and sampling chips). This avoids damage to the voltage divider resistors and sampling chips caused by back EMF and / or surge current, thereby improving the service life of the battery management system's signal acquisition circuit. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the first embodiment of the signal acquisition circuit of the battery management system of this application; Figure 2 This is a circuit diagram of the second embodiment of the signal acquisition circuit of the battery management system of this application; Figure 3 This is yet another circuit diagram of the signal acquisition circuit of the battery management system of this application; Figure 4 This is a circuit diagram of the signal acquisition circuit of the battery management system of this application in the third embodiment. Figure 5 This is yet another circuit diagram of the signal acquisition circuit of the battery management system of this application; Figure 6 This is a circuit diagram of the signal acquisition circuit of the battery management system of this application, according to the fourth embodiment. Figure 7 This is yet another circuit diagram of the signal acquisition circuit of the battery management system of this application; Figure 8 This is a schematic diagram of the framework of the first embodiment of the vehicle high-voltage system of this application.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0018] Explanation of icon numbers: 100. Signal acquisition circuit of battery management system; 200. Power battery; 300. Battery management system; 10. Fuse and absorption unit; 20. Isolation and filtering unit; F1. Fuse; R1. Varistor; 21. Common mode inductor; C1. First capacitor; C2. Second capacitor; L1. First inductor winding; L2. Second inductor winding; 30. Protection switching unit; 31. Current comparator; 32. Comparison current source; 33. Fuse switching subunit; Q1. Transistor; F2. Replacement fuse; 331. Two-to-one selection device; 400. Motor drive module; 410. Motor drive circuit; 420. Motor; 430. Motor controller. Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0020] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0021] The BMS (Battery Management System) 300 is the core controller of the power battery 200, requiring real-time and accurate monitoring of the battery pack's total voltage via a high-voltage acquisition line. However, when the vehicle's motor burns out due to overload, short circuit, or other reasons, it generates extremely high back electromotive force and surge current, which are conducted to the power battery 200's port via the DC bus. These strong interferences directly couple to the BMS's high-voltage acquisition signal, causing drastic fluctuations and jumps in the acquired values, and even damaging the BMS's internal precision voltage divider resistors and sampling chips, leading to system misjudgments, restarts, or permanent hardware damage. Existing BMS acquisition circuits typically only include simple RC filtering, which cannot effectively resist such extreme high-voltage surge impacts from the load side, posing significant safety hazards and maintenance costs. Common improvement methods focus on enhancing the anti-interference capabilities of the chips and circuits, a "passive" approach. However, this is often insufficient when facing extreme failures like motor burnout.

[0022] Therefore, based on the shortcomings of the signal acquisition circuit 100 of the battery management system 300 mentioned above, the signal acquisition circuit 100 of the battery management system 300 of this application is proposed. The main solution of the embodiment of this application is: when the power battery 200 outputs back electromotive force and / or surge current, the fuse and absorption unit 10 can be used to fuse and absorb the back electromotive force and / or surge current to obtain a normal acquisition signal, thereby obtaining a normal acquisition signal. At the same time, the normal acquisition signal is further isolated and filtered to obtain the target acquisition signal. That is, the fuse and absorption unit 10 and the isolation filtering unit 20 are used to eliminate the influence of back electromotive force and / or surge current on the battery management system 300 (such as damage to the voltage divider resistor and sampling chip), thereby avoiding the phenomenon that the battery management system 300 is damaged by back electromotive force and / or surge current. In other words, by using the fuse and absorption unit 10 and the isolation filtering unit 20, the influence of back electromotive force and / or surge current on the battery management system 300 is eliminated, thereby improving the service life of the signal acquisition circuit 100 of the battery management system 300.

[0023] Based on this, this application provides a signal acquisition circuit 100 for a battery management system 300, referring to... Figure 1 , Figure 1 This is a schematic diagram of the first embodiment of the signal acquisition circuit 100 of the battery management system 300 of this application.

[0024] Reference Figure 1 This application provides a signal acquisition circuit 100 for a battery management system 300, the signal acquisition circuit 100 of the battery management system 300 including: The fuse and absorption unit 10 has its first end connected to the positive terminal of the power battery 200 and its second end connected to the negative terminal of the power battery 200. The fuse and absorption unit 10 is used to fuse and absorb the back electromotive force and / or surge current to obtain a normal acquisition signal when the power battery 200 outputs back electromotive force and / or surge current. The isolation filtering unit 20 has its first end connected to the second end of the fuse and absorption unit 10, its second end connected to the third end of the fuse and absorption unit 10, its third end connected to the positive terminal of the battery management system 300, and its fourth end connected to the negative terminal of the battery management system 300. The isolation filtering unit 20 is used to isolate and filter the normal acquisition signal to obtain the target acquisition signal, so as to realize the signal acquisition of the battery management system 300.

[0025] In this embodiment, to avoid the influence of back EMF and / or surge current on the composition of the acquisition circuit, a fuse and absorption unit 10 can be designed in the signal acquisition circuit 100 of the battery management system 300. The fuse and absorption unit 10 is connected to the positive terminal and the negative terminal of the power battery 200. When the power battery 200 outputs back EMF and / or surge current, the fuse and absorption of back EMF and / or surge current can be used to obtain a normal acquisition signal. The back EMF and / or surge current may be generated by the motor burning out due to overload, short circuit, etc., and thus output by the power battery 200, affecting the information acquisition of the power battery 200 and the service life of the internal acquisition device. It may also be generated by other reasons, which are not limited here. Therefore, when the back electromotive force and / or surge current output by the power battery 200 passes through the fuse and absorption unit 10, the back electromotive force and / or surge current will be absorbed by the fuse and absorption unit 10. At the same time, the back electromotive force and / or surge current will also melt the line from the power battery 200 to the BMS, thereby protecting the BMS. It is worth noting that the design advantage of the fuse and absorption unit 10 is that if back EMF and / or surge current are present, the circuit between the power battery 200 and the BMS can be fused. At the same time, since the back EMF and / or surge current will still exist in the circuit after the fuse is fused, the signal at the moment of fuse fusion (the signals in this application all refer to current and voltage signals) can be absorbed so that the signal at the moment of fuse fusion meets the acquisition requirements without damaging the acquisition resistor or chip. Thus, the normal acquisition signal after fuse fusion and absorption of back EMF and / or surge current can be obtained. The normal acquisition signal refers to the signal after fuse fusion and absorption of back EMF and / or surge current. Fusing back EMF and / or surge current refers to fusing the output circuit of back EMF and / or surge current, thereby cutting off the back EMF and / or surge current to the power battery 200. For example, to ensure the accuracy of subsequent data acquisition, an isolation filtering unit 20 can be set after the fuse and absorption unit 10 to isolate and filter the normal acquisition signal, thereby obtaining the target acquisition signal. This enables the signal acquisition of the battery management system 300, filtering out differential-mode noise from the normal acquisition signal and outputting a clean and stable low-voltage signal to the BMS. The target acquisition signal refers to the normal acquisition signal after isolation and filtering. Finally, the target acquisition signal is passed through a sampling resistor and acquired based on the sampling resistor and the sampling chip. Of course, other acquisition circuit designs are also possible and are not limited here. Therefore, the entire design consists of a hardware protection circuit composed of three series-connected stages: fuse protection, surge absorption, and isolation filtering. These three lines of defense work together in time and space to achieve comprehensive protection from "coarse cut-off" to "fine filtering," thereby protecting the BMS sampling and improving the service life of the signal acquisition circuit 100 of the battery management system 300.

[0026] In this embodiment, a signal acquisition circuit 100 for a battery management system 300 is provided. The signal acquisition circuit 100 includes a fuse and absorption unit 10. The first terminal of the fuse and absorption unit 10 is connected to the positive terminal of a power battery 200, and the second terminal of the fuse and absorption unit 10 is connected to the negative terminal of the power battery 200. The fuse and absorption unit 10 is used to fuse and absorb the back electromotive force and / or surge current when the power battery 200 outputs a back electromotive force and / or surge current to obtain a normal acquisition signal. An isolation filtering unit 20 is also provided. The first terminal of the isolation filtering unit 20 is connected to the second terminal of the fuse and absorption unit 10, the second terminal of the isolation filtering unit 20 is connected to the third terminal of the fuse and absorption unit 10, the third terminal of the isolation filtering unit 20 is connected to the positive terminal of the battery management system 300, and the fourth terminal of the isolation filtering unit 20 is connected to the negative terminal of the battery management system 300. The isolation filtering unit 20 is used to isolate and filter the normal acquisition signal to obtain a target acquisition signal. To achieve signal acquisition of the battery management system 300, the signal acquisition circuit 100 of the battery management system 300 can use the fuse and absorption unit 10 to fuse and absorb the back EMF and / or surge current when the power battery 200 outputs it, thereby obtaining a normal acquisition signal. Simultaneously, the normal acquisition signal is further isolated and filtered to obtain the target acquisition signal. That is, the fuse and absorption unit 10 and the isolation filtering unit 20 are used to eliminate the influence of back EMF and / or surge current on the battery management system 300 (such as damage to the voltage divider resistor and sampling chip), thus avoiding damage to the voltage divider resistor and sampling chip caused by back EMF and / or surge current. In other words, by using the fuse and absorption unit 10 and the isolation filtering unit 20, the influence of back EMF and / or surge current on the battery management system 300 is eliminated, thereby improving the service life of the signal acquisition circuit 100 of the battery management system 300.

[0027] Furthermore, based on the first embodiment of this application described above, a second embodiment of the signal acquisition circuit 100 of the battery management system 300 of this application is proposed, referring to... Figure 2 , Figure 2 This is a circuit diagram of the signal acquisition circuit 100 of the battery management system 300 of this application in a second embodiment. The fuse and absorption unit 10 includes: Fuse F1, the first end of fuse F1 serves as the first end of the fusing and absorption unit 10 and is connected to the positive terminal of the power battery 200; The first end of the varistor R1 serves as the third end of the fuse and absorption unit 10, and is connected to the second end of the isolation filter unit 20 and the second end of the fuse F1. The second end of the varistor R1 serves as the second end of the fuse and absorption unit 10, and is connected to the negative terminal of the power battery 200 and the first end of the isolation filter unit 20.

[0028] In one embodiment, reference is made to Figure 3 , Figure 3 This is another circuit diagram of the signal acquisition circuit 100 of the battery management system 300 of this application. The fuse and absorption unit 10 includes: The first end of the varistor R1 serves as the first end of the fuse and absorption unit 10 and is connected to the positive terminal of the power battery 200. Fuse F1, the first end of fuse F1 serves as the third end of the fusing and absorption unit 10, and is connected to the second end of the isolation filter unit 20 and the second end of the varistor R1. The second end of fuse F1 serves as the second end of the fusing and absorption unit 10, and is connected to the negative terminal of the power battery 200 and the first end of the isolation filter unit 20.

[0029] In this embodiment, the fusing and absorption unit 10 is composed of a fuse F1 and a varistor R1 connected in series. The fuse F1 and varistor R1 can be connected in series with the fuse F1 first, at the very beginning of the high-voltage acquisition circuit. By connecting a small-current high-voltage DC fuse F1 in series, when the surge current exceeds the threshold, F1 will be the first to blow, physically and permanently cutting off the fault path, thus sacrificing itself to protect all the expensive core components downstream (such as voltage divider resistors and sampling chips). This is a "sacrifice the pawn to save the king" strategy with extremely high reliability. The varistor R1 is placed downstream because the fuse F1 alone is not fast enough; before it blows, the nanosecond-level high voltage spike may have already broken down the subsequent circuitry. The varistor R1, with its nanosecond-level response speed, can compensate for the slow response of the fuse F1. Furthermore, the instantaneous action of the varistor R1 can clamp the abnormal high voltage to a safe value and dissipate the huge surge energy, thereby preventing the high-voltage pulse from impacting the precision sampling components. It perfectly complements F1 in terms of response speed. Of course, other equivalent devices can be used to replace the fuse F1 and the varistor R1, which will not be discussed here.

[0030] In one embodiment, to avoid the fuse F1 blowing directly due to minor current or voltage fluctuations, the fuse F1 can be placed after the varistor R1. Thus, the fuse F1 will only be used for protection when the varistor R1 fails to absorb the voltage. This reduces the frequency of fuse F1 replacement, thereby reducing the overall circuit cost. It also avoids the phenomenon of the entire circuit becoming unusable due to minor fluctuations, thereby improving the accuracy of the signal acquisition circuit in handling back electromotive force and / or surge current.

[0031] In one embodiment, based on the first and / or second embodiments of this application described above, a third embodiment of the signal acquisition circuit 100 of the battery management system 300 of this application is proposed, referring to... Figure 4 , Figure 4 This is a circuit diagram of the signal acquisition circuit 100 of the battery management system 300 of this application in a third embodiment. The isolation filtering unit 20 includes: The common mode inductor 21 has the following characteristics: its first end serves as the first end of the isolation filter unit 20 and is connected to the second end of the fuse and absorption unit 10; its second end serves as the second end of the isolation filter unit 20 and is connected to the third end of the fuse and absorption unit 10; its third end serves as the second end of the isolation filter unit 20 and is connected to the positive terminal of the battery management system 300; and its fourth end serves as the third end of the isolation filter unit 20 and is connected to the negative terminal of the battery management system 300. The first capacitor C1 has its first terminal connected to the third terminal of the common mode inductor 21 and the positive terminal of the battery management system 300, and its second terminal connected to the fourth terminal of the common mode inductor 21 and the negative terminal of the battery management system 300. The second capacitor C2 has its first terminal connected to the third terminal of the common-mode inductor 21 and the positive terminal of the battery management system 300, and its second terminal connected to the fourth terminal of the common-mode inductor 21 and the negative terminal of the battery management system 300.

[0032] Furthermore, refer to Figure 5 , Figure 5 This is another circuit diagram of the signal acquisition circuit 100 of the battery management system 300 of this application. The common mode inductor 21 includes: The first inductor winding L1 has its first end serving as the first end of the common mode inductor 21 and connected to the second end of the fuse and absorption unit 10. The second end of the first inductor winding L1 serves as the third end of the common mode inductor 21 and is connected to the positive terminal of the battery management system 300. The second inductor winding L2 has its first end serving as the second end of the common-mode inductor 21 and connected to the third end of the fuse and absorption unit 10. The second end of the second inductor winding L2 also serves as the fourth end of the common-mode inductor 21 and is connected to the negative terminal of the battery management system 300.

[0033] In this embodiment, the isolation filtering unit 20 includes a common-mode inductor 21, a first capacitor C1, and a second capacitor C2. This allows for the addition of a π-type filter circuit composed of the common-mode inductor 21 and capacitors (C1, C2) before the signal finally enters the BMS chip. High-frequency noise generated by motor faults can interfere with the accuracy of the acquired signal, causing jumps in BMS calculations. Ordinary RC filters have limited effectiveness in suppressing common-mode interference. The common-mode inductor 21 can effectively suppress high-frequency common-mode interference, while the π-type filter composed of the inductor and capacitor can further filter out differential-mode noise. The signal, after being processed by melting and absorption, is "purified" in this unit, outputting a stable and smooth DC signal to the BMS ADC (Analog-to-Digital Converter), fundamentally eliminating fluctuations in the acquired value. For example, the common-mode inductor 21 includes a first inductor winding L1 and a second inductor winding L2, which can effectively suppress high-frequency common-mode interference. Furthermore, the synergistic effect of a three-tiered hardware protection system—"fuse-clamping-filtering"—fundamentally solves the problem of BMS data acquisition fluctuations or damage caused by motor burnout. Simultaneously, this circuit structure is simple, low-cost, fast-responding, and highly reliable, requiring no software intervention and easily integrated into existing BMS designs, significantly improving the system's robustness and security.

[0034] In one embodiment, based on the first, second, and / or third embodiments of this application described above, a fourth embodiment of the signal acquisition circuit 100 of the battery management system 300 is proposed. The signal acquisition circuit 100 of the battery management system 300 further includes a protection switching unit 30, as described above. Figure 6 , Figure 6 This is a circuit diagram of the signal acquisition circuit 100 of the battery management system 300 according to the fourth embodiment of this application. The protection switching unit 30 includes: Transistor Q1, the first end of transistor Q1 is connected to the second end of fuse F1 in fuse and absorption unit 10, and the second end of transistor Q1 is connected to the positive terminal of power battery 200. The first terminal of the current comparator 31 is connected to the third terminal of the transistor Q1, and the second terminal of the current comparator 31 is connected to the comparison current source 32 (the user can set the maximum sampling current). The fuse switching subunit 331 has its first terminal connected to the third terminal of the current comparator 31, its second terminal connected to the first terminal of the fuse F1, and its third terminal connected to the second terminal of the fuse F1.

[0035] Furthermore, refer to Figure 7 , Figure 7 This is another circuit diagram of the signal acquisition circuit 100 of the battery management system 300 of this application in a fourth embodiment. The fuse switching subunit 331 includes: Replace fuse F2, and connect the second end of fuse F2 to the second end of fuse F1. The two-to-one selection device 331 has its control terminal serving as the first terminal of the fuse switching subunit 331 and connected to the third terminal of the current comparator 31. The input terminal of the two-to-one selection device 331 serves as the second terminal of the fuse switching subunit 331 and is connected to the first terminal of the fuse F1. The first output terminal of the two-to-one selection device 331 serves as the third terminal of the fuse switching subunit 331 and is connected to the first terminal of the replacement fuse F2. The second output terminal of the two-to-one selection device 331 is left floating.

[0036] In this embodiment, since fuse F1 may blow due to back electromotive force and / or surge current, a replacement fuse F2 that automatically replaces it can be designed. The signal acquisition circuit 100 of the battery management system 300 also includes a protection switching unit 30. The protection switching unit 30 includes a transistor Q1, a current comparator 31, and a fuse switching subunit 331 composed of the replacement fuse F2 and a two-to-one selection device 331. The principle of transistor Q1 is that when there is current at the second terminal of fuse F1 (fuse F1 is not blown), transistor Q1 is cut off, that is, the third terminal of transistor Q1 is not connected to the second terminal of transistor Q1. In other words, the current comparator 31 has no comparison object or the comparison object is 0, so the output is high level, and then the high level is sent to the control terminal of the two-to-one selection device 331. At this time, the input terminal of the two-to-one selection device 331 is connected to the second output terminal of the two-to-one selection device 331. That is, at this time, fuse F1 is not blown, and fuse F1 continues to be used for protection. When there is no current at the second terminal of fuse F1 (fuse F1 blows), transistor Q1 turns on, meaning the third terminal of transistor Q1 is connected to the second terminal. This means the current comparator 31 compares the output of the power battery 200, resulting in a low-level output. This low level is then sent to the control terminal of the 2-to-1 selector 331. At this point, the input terminal of the 2-to-1 selector 331 is connected to its first output terminal, meaning fuse F1 blows again, and replacement fuse F2 continues to provide protection. To ensure accurate switching, the 2-to-1 selector 331 can be configured with two conducting levels. For example, if the output is 11 for two consecutive times (fuse F1 did not blow for two consecutive times), fuse F1 continues to provide protection. If the output is 01 for two consecutive times (fuse F1 blows for two consecutive times, and the power battery 200 drops below the comparison current source 32 in the latter time period), replacement fuse F2 is used for protection. It is worth noting that the 2-to-1 selector 331 is also configured so that when its input terminal is connected to its first output terminal, it is no longer controlled by its control terminal. This is to prevent the circuit from switching to a connection between the input terminal and the second output terminal of the 2-to-1 selector 331 after replacing fuse F2. For example, the above two level conductions can be implemented using a delay timer, where the delay is equal to the minimum output time of the current comparator 31. That is, when the current comparator 31 outputs, one signal is output directly, and the other signal is the previous signal. Alternatively, a controller can be used for storage, but this will not be elaborated upon here.The method of not being controlled by the control terminal of the two-to-one selection device 331 can be that after triggering the 01 level, the entire two-to-one selection device 331 automatically locks the input of the control terminal, thereby ensuring the accuracy of subsequent use. At the same time, based on the design of the protection switching unit 30, intelligent switching of fuses can be realized, thereby improving the intelligence of the signal acquisition circuit 100 of the battery management system 300.

[0037] Based on the first, second, third, and / or fourth embodiments of the signal acquisition circuit 100 of the battery management system 300 described above, a first embodiment of the vehicle high-voltage system of this application is proposed, with reference to... Figure 8 , Figure 8 This is a schematic diagram of the framework of the first embodiment of the vehicle high-voltage system of this application. The vehicle high-voltage system includes the signal acquisition circuit 100 of the battery management system 300, the battery management system 300, the power battery 200 and the motor drive module 400. The first terminal of the signal acquisition circuit 100 of the battery management system 300 is connected to the positive and negative terminals of the power battery 200, and the second terminal of the signal acquisition circuit 100 of the battery management system 300 is connected to the positive and negative terminals of the battery management system 300. The first terminal of the motor drive module 400 is connected to the positive and negative terminals of the power battery 200 through a high-voltage DC bus. The back electromotive force and / or surge current are generated by the motor drive module 400 and transmitted to the power battery 200 through the high-voltage DC bus.

[0038] In this embodiment, when the motor 420 stops due to a fault or other malfunction, it generates back electromotive force and / or surge current, which is transmitted to the power battery 200 through the first terminal of the motor drive module 400 and the high-voltage DC bus. When the power battery 200 is collecting information, the back electromotive force and / or surge current are transmitted to the signal acquisition circuit 100 of the battery management system 300, potentially damaging the sampling resistor and sampling chip in the signal acquisition circuit 100. Therefore, the signal acquisition circuit 100 of the battery management system 300 uses a fuse and absorption unit 10 to fuse and absorb the back electromotive force and / or surge current to obtain a normal acquisition signal. This normal acquisition signal is then filtered by the isolation and filtering unit 20 to obtain the target acquisition signal, thus enabling signal acquisition by the battery management system 300 and avoiding the influence of back electromotive force and / or surge current, thereby improving the service life of the signal acquisition circuit 100. It is worth noting that the signal acquisition circuit 100 of the battery management system 300 can also be applied to other systems with back electromotive force and / or surge current, which will not be described in detail here.

[0039] Based on the first embodiment of this application described above, a second embodiment of the vehicle high-voltage system of this application is proposed, wherein the motor drive module 400 includes: Motor controller 430 and motor 420; The motor drive circuit 410 has a first terminal that serves as the first terminal of the motor drive module 400 and is connected to the positive and negative terminals of the power battery 200. The second terminal of the motor drive circuit 410 is connected to the motor controller 430, and the third terminal of the motor drive circuit 410 is connected to the motor 420.

[0040] In this embodiment, the motor drive module 400 includes a motor controller 430, a motor 420, and a motor drive circuit 410. The motor drive circuit 410 can be a three-phase motor drive circuit, such as consisting of three drive bridge arms. Each drive bridge arm is composed of two switching transistors connected in series, with the midpoint of the two switching transistors serving as the output terminal, which is then connected to the motor 420. The control terminals of the two switching transistors are connected to the motor controller 430. Alternatively, it can be a single-phase motor drive circuit, which is not limited here. The motor controller 430 can be a commonly used controller for driving motors. However, when the motor 420 malfunctions, the back electromotive force and / or surge current will be transmitted to the power battery 200 through the high-voltage DC bus, thereby affecting the subsequent information acquisition function of the power battery 200. Therefore, the signal acquisition circuit 100 of the battery management system 300 of this application is proposed to improve the service life of the signal acquisition circuit 100 of the battery management system 300.

[0041] Based on the above embodiment of the signal acquisition circuit 100 of the battery management system 300, a vehicle is proposed, the vehicle including the above-mentioned vehicle high voltage system.

[0042] In this embodiment, when the power battery 200 outputs back EMF and / or surge current through the vehicle's high-voltage system, the fuse and absorption unit 10 can be used to fuse and absorb the back EMF and / or surge current to obtain a normal acquisition signal. Simultaneously, the normal acquisition signal is further isolated and filtered to obtain the target acquisition signal. That is, the fuse and absorption unit 10 and the isolation filtering unit 20 are used to eliminate the influence of back EMF and / or surge current on the battery management system 300 (such as damage to the voltage divider resistor and sampling chip). This avoids damage to the voltage divider resistor and sampling chip caused by back EMF and / or surge current. In other words, by using the fuse and absorption unit 10 and the isolation filtering unit 20, the influence of back EMF and / or surge current on the battery management system 300 is eliminated, thereby improving the service life of the signal acquisition circuit 100 of the battery management system 300. Furthermore, the entire vehicle high-voltage system can ensure the accuracy of information collection and the service life of internal components. For example, various operations are performed based on the collected information. The accuracy of information collection ensures the accuracy of the operation, thereby protecting the components performing the operation.

[0043] The above are only some embodiments of this application and do not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A signal acquisition circuit for a battery management system, characterized in that, The signal acquisition circuit of the battery management system includes: A fuse and absorption unit is provided, wherein the first end of the fuse and absorption unit is connected to the positive terminal of the power battery, and the second end of the fuse and absorption unit is connected to the negative terminal of the power battery. The fuse and absorption unit is used to fuse and absorb the back electromotive force and / or the surge current when the power battery outputs back electromotive force and / or surge current to obtain a normal acquisition signal. An isolation filtering unit is provided, wherein a first end of the isolation filtering unit is connected to a second end of the fuse and absorption unit, a second end of the isolation filtering unit is connected to a third end of the fuse and absorption unit, a third end of the isolation filtering unit is connected to the positive terminal of the battery management system, and a fourth end of the isolation filtering unit is connected to the negative terminal of the battery management system. The isolation filtering unit is used to isolate and filter the normal acquisition signal to obtain the target acquisition signal, thereby realizing the signal acquisition of the battery management system.

2. The signal acquisition circuit of the battery management system as described in claim 1, characterized in that, The fusing and absorbing unit includes: A fuse, the first end of which serves as the first end of the fusing and absorption unit and is connected to the positive terminal of the power battery; A varistor, wherein the first end of the varistor serves as the third end of the fuse and absorption unit, and is connected to the second end of the isolation filter unit and the second end of the fuse; the second end of the varistor serves as the second end of the fuse and absorption unit, and is connected to the negative terminal of the power battery and the first end of the isolation filter unit.

3. The signal acquisition circuit of the battery management system as described in claim 1, characterized in that, The fusing and absorbing unit includes: A varistor, the first end of which serves as the first end of the fuse and absorption unit and is connected to the positive terminal of the power battery; A fuse, the first end of which serves as the third end of the fusing and absorption unit, is connected to the second end of the isolation filter unit and the second end of the varistor. The second end of the fuse serves as the second end of the fusing and absorption unit and is connected to the negative terminal of the power battery and the first end of the isolation filter unit.

4. The signal acquisition circuit of the battery management system as described in claim 1, characterized in that, The isolation filtering unit includes: A common-mode inductor, wherein the first terminal of the common-mode inductor serves as the first terminal of the isolation filter unit and is connected to the second terminal of the fuse and absorption unit; the second terminal of the common-mode inductor serves as the second terminal of the isolation filter unit and is connected to the third terminal of the fuse and absorption unit; the third terminal of the common-mode inductor serves as the second terminal of the isolation filter unit and is connected to the positive terminal of the battery management system; and the fourth terminal of the common-mode inductor serves as the third terminal of the isolation filter unit and is connected to the negative terminal of the battery management system. A first capacitor, wherein a first terminal of the first capacitor is connected to a third terminal of the common-mode inductor and the positive terminal of the battery management system, and a second terminal of the first capacitor is connected to a fourth terminal of the common-mode inductor and the negative terminal of the battery management system. The second capacitor has its first terminal connected to the third terminal of the common-mode inductor and the positive terminal of the battery management system, and its second terminal connected to the fourth terminal of the common-mode inductor and the negative terminal of the battery management system.

5. The signal acquisition circuit of the battery management system as described in claim 4, characterized in that, The common-mode inductor includes: The first inductor winding has a first end that serves as the first end of the common mode inductor and is connected to the second end of the fuse and absorption unit. The second end of the first inductor winding serves as the third end of the common mode inductor and is connected to the positive terminal of the battery management system. The second inductor winding has a first end that serves as the second end of the common-mode inductor and is connected to the third end of the fuse and absorption unit. The second end of the second inductor winding serves as the fourth end of the common-mode inductor and is connected to the negative terminal of the battery management system.

6. The signal acquisition circuit of the battery management system as described in claim 1, characterized in that, The signal acquisition circuit of the battery management system further includes a protection switching unit, which includes: The transistor has its first end connected to the second end of the fuse in the fusing and absorption unit, and its second end connected to the positive terminal of the power battery. A current comparator, wherein the first terminal of the current comparator is connected to the third terminal of the transistor, and the second terminal of the current comparator is connected to a comparison current source; A fuse switching subunit, wherein the first terminal of the fuse switching subunit is connected to the third terminal of the current comparator, the second terminal of the fuse switching subunit is connected to the first terminal of the fuse, and the third terminal of the fuse switching subunit is connected to the second terminal of the fuse.

7. The signal acquisition circuit of the battery management system as described in claim 6, characterized in that, The fuse switching subunit includes: A replacement fuse is provided, wherein the second end of the replacement fuse is connected to the second end of the original fuse. The two-to-one selection device has a control terminal that serves as the first terminal of the fuse switching subunit and is connected to the third terminal of the current comparator. The input terminal of the two-to-one selection device serves as the second terminal of the fuse switching subunit and is connected to the first terminal of the fuse. The first output terminal of the two-to-one selection device serves as the third terminal of the fuse switching subunit and is connected to the first terminal of the replacement fuse. The second output terminal of the two-to-one selection device is left floating.

8. A vehicle high-voltage system, characterized in that, The vehicle high-voltage system includes a signal acquisition circuit, a battery management system, a power battery, and a motor drive module as described in any one of claims 1 to 7. The first terminal of the signal acquisition circuit of the battery management system is connected to the positive and negative terminals of the power battery, and the second terminal of the signal acquisition circuit of the battery management system is connected to the positive and negative terminals of the battery management system. The first terminal of the motor drive module is connected to the positive and negative terminals of the power battery through a high-voltage DC bus. The back electromotive force and / or the surge current are generated by the motor drive module and transmitted to the power battery through the high-voltage DC bus.

9. The vehicle high-voltage system as described in claim 8, characterized in that, The motor drive module includes: Motor controller and motor; The motor drive circuit has a first terminal serving as the first terminal of the motor drive module and connected to the positive and negative terminals of the power battery. The second terminal of the motor drive circuit is connected to the motor controller, and the third terminal of the motor drive circuit is connected to the motor.

10. A vehicle, characterized in that, The vehicle includes the high-voltage system of any one of claims 8 to 9.

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