A battery management system

Abstract

The application discloses a battery management system and belongs to the technical field of power batteries. The battery management system comprises an MCU circuit, a low-voltage connector, a high-voltage connector and a battery acquisition connector. A second isolation unit is arranged between the high-voltage connector and the MCU circuit, and a third isolation unit is arranged between the battery acquisition connector and the MCU circuit, so that an isolation circuit is formed between a high-voltage circuit and a low-voltage circuit. A first isolation unit is arranged between the low-voltage connector and the MCU circuit, so that an isolation circuit is formed between a BMS system and other controllers of a whole vehicle. When a single-point fault occurs between high-voltage and low-voltage circuits of the BMS, the additional isolation circuit can guarantee that a driver and passengers will not be hurt by accidental electric shock.

Description

Technical Field

[0001] This utility model belongs to the field of power battery technology, and specifically relates to a battery management system. Background Technology

[0002] With the development of electric vehicles, their safety performance has gradually attracted attention. Among them, the high-voltage system is an important component of electric vehicles, responsible for storing and managing the high-voltage electrical energy of electric vehicles. The safety of the high-voltage system is receiving increasing attention. The battery management system (BMS) is an important component of the power battery system. The main function of the BMS is to ensure that the battery pack operates under safe and stable conditions, extend its service life, and improve energy utilization efficiency. The BMS is the link between the high-voltage system and the low-voltage system of an electric vehicle.

[0003] To prevent accidental electric shock to occupants during the use of electric vehicles, the high and low voltage systems must be isolated. Currently, most mainstream battery management systems on the market adopt high and low voltage isolation designs, meeting the insulation and withstand voltage test requirements under 800V high voltage systems. However, given the complexity of the automotive operating environment, issues such as wiring aging and insulation failure can still lead to risks of electric shock and leakage. This places higher design requirements on the high voltage safety of electric vehicles. For example, existing standards require that the high voltage and accessible low voltage components meet one of the following three insulation methods: (1) Double insulation or reinforced insulation; (2) Basic insulation is used and, in the event of a single point of failure, the voltage on the accessible Class A voltage terminals of Class B voltage components is limited to below 60V DC or 30V AC. (3) Basic insulation is used and, in the event of a single point of failure, the steady-state contact current between the accessible Class A voltage terminal of the Class B voltage component and the conductive component is limited to below 3.5mA AC and 10mA DC, while the contact energy is below the specified ventricular fibrillation limit and has sufficient margin.

[0004] Existing BMS designs are insufficient to meet the requirements. Utility Model Content

[0005] The purpose of this invention is to provide a battery management system to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a battery management system, comprising: MCU circuit; A low-voltage connector is connected to the MCU circuit, and a first isolation unit is configured between the low-voltage connector and the MCU circuit; A high-voltage connector is connected to the MCU circuit, and a second isolation unit is configured between the high-voltage connector and the MCU circuit; A battery acquisition connector is connected to the MCU circuit, and a third isolation unit is configured between the battery acquisition connector and the MCU circuit.

[0007] This application establishes an isolation circuit between the high-voltage and low-voltage circuits by using a second isolation unit located between the high-voltage connector and the MCU circuit, and a third isolation unit located between the battery acquisition connector and the MCU circuit. By using a first isolation unit located between the low-voltage connector and the MCU circuit, an isolation circuit is established between the BMS system and other controllers in the vehicle. When a single point of failure occurs between the high-voltage and low-voltage circuits of the BMS, the additional isolation circuit can ensure that the occupants will not be injured by accidental electric shock.

[0008] Furthermore, the battery management system also includes a high-voltage acquisition and insulation detection module, which is connected to the MCU circuit and the high-voltage connector, and the second isolation unit includes an isolation operational amplifier circuit configured between the MCU circuit and the high-voltage acquisition and insulation monitoring module.

[0009] Furthermore, the second isolation unit also includes an optocoupler isolation configured between the MCU circuit and the high-voltage acquisition and insulation monitoring module, and the isolation operational amplifier circuit and the optocoupler isolation are connected in parallel.

[0010] Furthermore, the battery management system also includes an AFE circuit, which is connected to the battery acquisition connector and the MCU circuit, and the third isolation unit includes a transformer isolation configured between the AFE circuit and the MCU circuit.

[0011] Furthermore, the battery management system also includes a communication conversion circuit configured between the transformer isolation and the MCU circuit.

[0012] Furthermore, the first isolation unit includes an isolated CAN bus, which is directly connected to the MCU circuit and the low-voltage connector.

[0013] Furthermore, the first isolation unit includes an isolation ADC, which is directly connected to the MCU circuit and the low-voltage connector.

[0014] Furthermore, the battery management system also includes a PWM circuit, and the first isolation unit includes isolation I / O configured between the PWM circuit and the low-voltage connector.

[0015] Furthermore, the first isolation unit includes an isolated power supply configured between the MCU circuit and the low-voltage connector.

[0016] Furthermore, the battery management system also includes a power conversion circuit, which is connected to the MCU circuit and the isolated power supply. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall battery management system of this application. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] A battery management system, as described above Figure 1 The main body consists of an MCU (Microcontroller Unit Circuit), a low-voltage connector, a high-voltage connector (battery high-voltage signal connector), and a battery acquisition connector. The low-voltage connector serves as a low-voltage communication plug between the battery management system and other controllers in the vehicle (such as the vehicle controller and motor controller). The low-voltage connector is connected to the MCU circuit, and a first isolation unit is configured between the low-voltage connector and the MCU circuit. The high-voltage connector serves as a connection plug between the battery management system and the internal and external total voltages of the power battery. The high-voltage connector is connected to the MCU circuit, and a second isolation unit is configured between the high-voltage connector and the MCU circuit. Correspondingly, the battery acquisition connector serves as a data acquisition plug for the individual operating data of the power battery cells. The battery acquisition connector is connected to the MCU circuit, and a third isolation unit is configured between the battery acquisition connector and the MCU circuit. The second and third isolation units form an isolation unit between the high-voltage and low-voltage circuits. The first isolation unit serves as an additional isolation unit between the BMS system and other controllers in the vehicle. When a single point of failure occurs between the high and low voltage circuits of the BMS, the additional isolation circuit can ensure that the occupants will not suffer accidental electric shock.

[0020] In some embodiments, the battery management system further includes a high-voltage acquisition and insulation detection module. This module is connected to a high-voltage connector to receive a high-voltage signal output from the connector. Simultaneously, the module is connected to an MCU circuit. Correspondingly, the second isolation unit includes an isolation operational amplifier power supply and optocoupler isolation configured between the MCU circuit and the high-voltage acquisition and insulation detection module. The isolation operational amplifier power supply and optocoupler isolation are connected in parallel. In this case, the MCU circuit outputs an I / O signal to the optocoupler isolation circuit and controls the on / off state of the high-voltage acquisition and insulation detection module. The high-voltage acquisition and insulation detection module outputs an analog signal to the isolation operational amplifier circuit. The isolation operational amplifier circuit outputs the isolated analog signal to the analog acquisition channel of the MCU circuit to complete the high-voltage and insulation acquisition functions.

[0021] In some embodiments, the battery pipeline module further includes an AFE circuit (Analog Front End Circuit) and a communication conversion circuit. The AFE circuit is connected to the battery acquisition connector to receive battery cell operating data (e.g., temperature and voltage), and the communication conversion circuit is connected to the MCU circuit. Correspondingly, the third isolation unit includes a transformer isolation unit disposed between the AFE circuit and the communication conversion circuit. When the battery management system is in operation, the MCU circuit converts the SPI signal into a daisy-chain signal through the communication conversion circuit. The daisy-chain signal communicates with the AFE circuit after passing through the transformer isolation circuit to complete battery voltage acquisition, temperature acquisition, equalization management, and fault alarm.

[0022] In some embodiments, the battery management system further includes a power conversion circuit. Correspondingly, the first isolation unit includes an isolation power supply configured between the power conversion circuit and the low-voltage connector. The low-voltage connector outputs KL_30 (positive power supply of the vehicle's low-voltage battery), KL_31 (negative power supply of the vehicle's low-voltage battery), and a wake-up signal to the isolation power supply. The isolation power supply outputs the isolated power supply PWR (positive power supply of the BMS) and GND (negative power supply of the BMS) to the power conversion circuit. The power conversion circuit outputs the digital circuit power supply VCCD, the analog circuit power supply VCCA, and the reference power supply VREF required for system operation.

[0023] In some embodiments, the first isolation unit further includes an isolation ADC. When the power management system is running, the low-voltage connector outputs CC and CC2 analog signals to the isolation ADC. The isolation ADC communicates with the MCU circuit through the IIC signal to realize the acquisition of the slow charging CC signal and the fast charging CC2 signal.

[0024] In some embodiments, the first isolation unit further includes an isolated CAN bus. The isolated CAN bus is connected to the MCU circuit and the low-voltage connector. When the battery management system is running, it communicates with the isolated CAN bus via CAN_TX and CAN_RX signals. The isolated CAN bus outputs isolated CAN_H and CAN_L signals to the low-voltage connector to realize communication between the battery pipeline system and other controllers of the vehicle.

[0025] In some embodiments, the battery management system further includes a PWM (Pulse Width Modulation) circuit connected to the MCU circuit. Correspondingly, the first isolation unit includes an isolation I / O configured between the PWM circuit and the low-voltage connector. When the battery management system is running, the MCU circuit outputs an HVIL_CTRL (loop interlock) signal to the PWM circuit, the PWM circuit outputs an HVIL_OUT signal (loop interlock output signal) to the isolation I / O circuit, the isolation I / O circuit outputs the isolated HVIL_OUT signal to the low-voltage connector to achieve loop interlock output, the low-voltage connector outputs an HVIL_IN signal (loop interlock input signal) to the isolation I / O circuit, the isolation I / O circuit outputs the isolated HVIL_IN signal to the PWM circuit, and the PWM circuit outputs an HVIL_ST signal to the MCU circuit for loop interlock acquisition.

[0026] In some embodiments, the low-voltage connector outputs a CP signal (slow charging signal) to the isolation I / O circuit, the isolation I / O circuit outputs the isolated CP signal to the PWM circuit, and the PWM circuit outputs CP_ST to the MCU circuit to complete the slow charging CP signal acquisition function.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A battery management system, characterized in that, include: MCU circuit; A low-voltage connector is connected to the MCU circuit, and a first isolation unit is configured between the low-voltage connector and the MCU circuit; A high-voltage connector is connected to the MCU circuit, and a second isolation unit is configured between the high-voltage connector and the MCU circuit; A battery acquisition connector is connected to the MCU circuit, and a third isolation unit is configured between the battery acquisition connector and the MCU circuit.

2. The battery management system according to claim 1, characterized in that: The battery management system further includes a high-voltage acquisition and insulation detection module, which is connected to the MCU circuit and the high-voltage connector. The second isolation unit includes an isolation operational amplifier circuit configured between the MCU circuit and the high-voltage acquisition and insulation monitoring module.

3. A battery management system according to claim 2, characterized in that: The second isolation unit also includes an optocoupler isolation configured between the MCU circuit and the high voltage acquisition and insulation monitoring module, and the isolation operational amplifier circuit and the optocoupler isolation are connected in parallel.

4. A battery management system according to claim 1, characterized in that: The battery management system further includes an AFE circuit, which is connected to the battery acquisition connector and the MCU circuit, and the third isolation unit includes a transformer isolation configured between the AFE circuit and the MCU circuit.

5. A battery management system according to claim 4, characterized in that: The battery management system also includes a communication conversion circuit configured between the transformer isolation and the MCU circuit.

6. A battery management system according to claim 1, characterized in that: The first isolation unit includes an isolated CAN bus, which is directly connected to the MCU circuit and the low-voltage connector.

7. A battery management system according to claim 1, characterized in that: The first isolation unit includes an isolation ADC, which is directly connected to the MCU circuit and the low-voltage connector.

8. A battery management system according to claim 1, characterized in that: The battery management system further includes a PWM circuit, and the first isolation unit includes isolation I / O configured between the PWM circuit and the low-voltage connector.

9. A battery management system according to claim 1, characterized in that: The first isolation unit includes an isolated power supply configured between the MCU circuit and the low-voltage connector.

10. A battery management system according to claim 9, characterized in that: The battery management system also includes a power conversion circuit, which is connected to the MCU circuit and the isolated power supply.

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