Battery management system and automobile

Abstract

The utility model relates to the technical field of battery management, and discloses a battery management system and an automobile, and the system comprises a battery pack which comprises a plurality of battery cells; the plurality of battery sampling chips are connected in a daisy chain series structure, and two ends of each battery sampling chip are connected with two ends of the battery cell; the first end of the main control chip is connected with the two ends of the battery sampling chip; the first end of the voltage-stabilized source is connected with the second end of the main control chip, and the second end and the third end of the voltage-stabilized source are connected with the two ends of the battery pack respectively; the first end of the battery pack monitoring chip is connected with the third end of the main control chip, the second end of the battery pack monitoring chip is connected with the first end of the battery pack, and the third end of the battery pack monitoring chip is connected with the third end of the stabilized voltage supply. The system can determine the health state and the charging state of the battery based on the electrochemical AC impedance spectroscopy technology, thereby controlling the charging process and the like of the battery according to the state of the battery, avoiding the risk of thermal runaway of the battery in advance, prolonging the service life of the battery, and improving the customer experience.

Description

Technical Field

[0001] The utility model relates to the technical field of battery management, in particular to a battery management system and an automobile. Background Art

[0002] With the breakthrough and maturity of new energy electric vehicle power battery technology, the entire vehicle is generally moving towards high-voltage fast charging and long driving range, which also puts higher requirements on the safety and reliability of the vehicle battery.

[0003] Currently, there are limited early warning measures to avoid the risks brought about by thermal runaway of battery cells. These measures are usually taken after a fault occurs. For example, after monitoring the relevant signals of thermal runaway (local overtemperature on the battery cell surface, sudden change in battery cell voltage, overcurrent in the power circuit, sudden change in air pressure in the pack, smoke alarm), risks can be avoided by cutting off power and urgently evacuating the driver and passengers away from the faulty vehicle.

[0004] Therefore, existing technologies are unable to directly detect and warn of battery thermal runaway events in advance through effective means, and there are cases of missed or false alarms of thermal runaway, which may lead to safety accidents or affect the user experience. Utility Model Content

[0005] In view of this, the present invention provides a battery management system and a vehicle to solve the problem of being unable to detect the risk of thermal runaway in advance.

[0006] In the first aspect, the present invention provides a battery management system, comprising: a battery pack, a battery sampling chip, a main control chip, a voltage-stabilized power supply and a battery pack monitoring chip, wherein the battery pack comprises a plurality of battery cells; a plurality of battery sampling chips connected in series in a daisy chain structure, and the two ends of each battery sampling chip are connected to the two ends of the battery cell; a main control chip, the first end of the main control chip is connected to the two ends of the battery sampling chip; a voltage-stabilized power supply, the first end of the voltage-stabilized power supply is connected to the second end of the main control chip, and the second and third ends of the voltage-stabilized power supply are respectively connected to the two ends of the battery pack; a battery pack monitoring chip, the first end of the battery pack monitoring chip is connected to the third end of the main control chip, the second end of the battery pack monitoring chip is connected to the first end of the battery pack, and the third end of the battery pack monitoring chip is connected to the third end of the voltage-stabilized power supply.

[0007] The battery management system provided by the embodiment of the present utility model connects the battery pack, the battery sampling chip, the main control chip, the voltage-stabilized power supply and the battery pack monitoring chip. The main control chip controls the voltage-stabilized power supply to generate an excitation current. The battery sampling chip and the battery pack monitoring chip synchronously detect the excitation voltage signal and the excitation current signal on the battery pack cell based on the main control chip. The battery health state and charging state can be determined based on the electrochemical AC impedance spectroscopy technology, so as to control the battery charging process according to the battery state, avoid the risk of thermal runaway of the battery in advance, increase battery life, and enhance customer experience.

[0008] In an optional embodiment, the system further includes: a shunt, wherein two ends of the shunt are respectively connected to the second end and the third end of the battery pack monitoring chip.

[0009] The utility model provides a shunt, which can facilitate the battery pack monitoring chip to detect the excitation current signal, thereby obtaining the cell impedance when the battery cell is excited.

[0010] In an optional embodiment, the system further includes: a battery connected to the fourth terminal of the regulated power supply.

[0011] The utility model is provided with a storage battery, which can store energy during the charging process, thereby ensuring the normal starting of the car.

[0012] In an optional embodiment, the number of the battery sampling chips does not exceed the number of the battery cells, and each of the battery sampling chips is connected to both ends of at least one of the battery cells.

[0013] The utility model connects a battery sampling chip at both ends of each battery cell or multiple battery cells, thereby being able to synchronously obtain the excitation voltage signal of the battery cells, and providing data support for accurately grasping the relevant status of the battery.

[0014] In an optional embodiment, the two battery sampling chips at both ends of the series structure are connected to the first end of the main control chip via a bridge chip.

[0015] The utility model manages the bus interface between the main control chip and the battery sampling chip through the bridge chip, can realize the communication between the main control chip and the battery sampling chip, overcomes the limitation between the host interface and the peripherals, and makes the design more flexible.

[0016] In an optional embodiment, the two battery sampling chips at both ends of the series structure are respectively connected to the first end and the second end of the bridge chip in a daisy chain topology; the third end of the bridge chip is connected to the first end of the main control chip via a full-duplex synchronous serial bus.

[0017] The utility model can simultaneously collect the excitation voltage signals at both ends of each cell in the battery pack by daisy-chaining the cell and the cell sampling chip, realize the synchronization of the excitation voltage signals on each cell at a specific frequency, and thus obtain the cell impedance under the excitation of the cell.

[0018] In an optional implementation, the third terminal of the main control chip is connected to the first terminal of the battery pack monitoring chip via a full-duplex synchronous serial bus.

[0019] The utility model connects the battery sampling chip and the battery pack monitoring chip through the main control chip, which can further realize the synchronization of the excitation voltage signal and the excitation current signal, thereby obtaining data such as the cell impedance (imaginary part, real part) under the excitation of the battery cell, the excitation frequency, and the phase of the voltage and current of the battery cell under the excitation.

[0020] In an optional implementation, the second end of the main control chip is connected to the first end of the regulated power supply via a serial communication protocol bus.

[0021] The utility model is connected to the voltage-stabilized power supply through the main control chip, which can notify the voltage-stabilized power supply to generate an excitation signal of a specific frequency, thereby generating an AC excitation signal on all series battery cell bus bars and shunt bus bars, providing data for the realization of accurate battery status evaluation.

[0022] In an optional embodiment, the system also includes: a first switching tube, arranged on the connecting line between the second end of the regulated power supply and the second end of the battery pack; a second switching tube, arranged on the connecting line between the third end of the regulated power supply and the third end of the battery pack monitoring chip.

[0023] The utility model provides a switch tube on the connecting line, which can be opened and closed according to a specific frequency, thereby converting the direct current generated by the voltage-stabilized power supply into alternating current and generating an alternating voltage signal on the battery cell of the battery pack.

[0024] In a second aspect, the present invention further provides an automobile, comprising the battery management system of the first aspect or any corresponding embodiment thereof.

[0025] The automobile provided by the present invention has the same effect as the battery management system because the automobile includes a battery management system, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic structural diagram of a battery management system according to an embodiment of the present utility model;

[0028] Figure 2 This is the Nyquist diagram of the battery management system according to an embodiment of the present invention.

[0029] Description of reference numerals:

[0030] 100-battery pack; 101-battery cell; 200-battery sampling chip; 300-main control chip; 400-voltage-stabilized power supply; 500-battery pack monitoring chip; 600-shunt; 700-battery; 800-bridge chip; 901-first switch tube; 902-second switch tube. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0032] The embodiment of the present utility model is applicable to the scenario of early detection of thermal runaway events during the fast charging process of lithium batteries in new energy electric vehicles. At present, due to the limitations of the selection of excitation sources, energy efficiency utilization, and cost constraints, the real-time detection of battery cells in the battery pack by on-board EIS (Electrochemical Impedance Spectroscopy) has not been realized. The EIS technology remains in the detection process of battery cell production and assembly production lines. For example, the production line usually requires dedicated large-scale EIS detection equipment to support offline detection. In addition, there is a certain deviation in the current model estimation of the battery life SOC (State of Charge) / SOH (State of Health) algorithm, which has certain limitations on the fast charging efficiency and battery pack life, and the battery cell life decay cannot be effectively delayed.

[0033] This utility model provides a battery management system, which is installed on the vehicle and samples the excitation signal during the battery charging process to achieve EIS detection of all cells in the battery pack under multiple working conditions of the actual vehicle, accurately identify the charging state and health state of the battery pack, and avoid thermal runaway. Figure 1 and Figure 2 , describing the embodiments of the present utility model.

[0034] According to an embodiment of the present invention, on the one hand, a battery management system is provided, such as Figure 1 As shown, the system includes: a battery pack 100, a battery sampling chip 200, a main control chip 300, a regulated power supply 400 and a battery pack monitoring chip 500, wherein the battery pack 100 includes multiple battery cells 101; multiple battery sampling chips 200 connected in series in a daisy chain structure, and the two ends of each battery sampling chip 200 are connected to the two ends of the battery cell 101; the main control chip 300, the first end of the main control chip 300 is connected to the two ends of the battery sampling chip 200; the regulated power supply 400, the first end of the regulated power supply 400 is connected to the second end of the main control chip 300, and the second and third ends of the regulated power supply 400 are respectively connected to the two ends of the battery pack 100; the battery pack monitoring chip 500, the first end of the battery pack monitoring chip 500 is connected to the third end of the main control chip 300, the second end of the battery pack monitoring chip 500 is connected to the first end of the battery pack 100, and the third end of the battery pack monitoring chip 500 is connected to the third end of the regulated power supply 400.

[0035] Specifically, in the embodiment of the present invention, a specific BMS (Battery Management System) system architecture is set based on the EIS technology principle. Among them, the EIS technology is to apply a small amplitude AC disturbance excitation voltage signal at different frequencies to the electrochemical system (lithium battery), measure the ratio of the AC potential to the current signal (the impedance of the system) as the frequency ω changes, and then obtain the impedance (imaginary part, real part), impedance modulus and excitation current voltage phase angle at different frequencies, and draw a graph to obtain the electrochemical impedance spectrum. Since the disturbance electrical signal is an AC signal, the electrochemical impedance spectrum is also called the AC impedance spectrum. The information in EIS is usually represented by a Nyquist diagram, such as Figure 2 As shown, in the Nyquist plot, the imaginary component of impedance (y-axis) is plotted against the real component of impedance (x-axis). The specific meaning is conventional technical means in this field and will not be repeated here. The different regions of the Nyquist plot correspond to the various chemical and physical processes occurring in the battery. These data can be used in battery cell modeling to determine the state of health (SOH) and state of charge (SOC) of the lithium battery.

[0036] In some optional embodiments, such as Figure 1As shown, the battery pack 100 of the embodiment of the present invention includes a plurality of battery cells 101 connected in series in sequence. The battery pack 100 is called a Pack, and the specific number of battery cells 101 is determined according to the power performance of the car. In order to meet the application conditions of the EIS technology, a main control chip 300 and a voltage-stabilized power supply 400 are deployed in the battery management system, wherein the main control chip is an MCU (Microcontroller Unit), and the voltage-stabilized power supply 400 is a DC / DC module. The DC / DC module can convert electrical energy of one voltage value into electrical energy of another voltage value, for example only and not limited to this. The DC / DC module serves as the excitation source in the Pack, and its two ends are respectively connected to the battery cells 101 at both ends of the battery pack 100, and a first switch tube 901 and a second switch tube 902 are deployed on the two connecting lines, and the DC / DC module and the MCU are connected via a serial communication protocol (CAN, Controller Area Network) bus.

[0037] In some optional embodiments, such as Figure 1 As shown, in order to collect excitation signals for the battery pack 100 or the battery cells 101 in the battery pack 100 during the battery charging process, an embodiment of the present invention connects a battery sampling chip 200, commonly referred to as an AFE (Analog Front End) chip, such as a Cell Monitor Unit (CMU), at both ends of each battery cell 101, or at both ends of multiple series-connected battery cells 101. The chip is responsible for synchronously measuring the voltage parameters of each battery cell 101 at a specific frequency. Therefore, it includes multiple AFE chips, the number of AFE chips does not exceed the number of battery cells 101, and all AFE chips are connected in series in sequence to form a series structure. The two AFE chips at both ends of the series structure are respectively connected to a bridge chip 800 to form a daisy chain topology. At the same time, the bridge chip 800 converts the daisy chain into an SPI (Serial Peripheral Interface, a full-duplex synchronous serial interface) and connects to the MCU through the SPI bus, so that the battery cell excitation voltage signal collected by the AFE chip can be parsed and transmitted to the MCU through the bridge chip 800. By managing the bus interface between the main control chip and the battery sampling chip through the bridge chip, communication between the main control chip and the battery sampling chip can be achieved, overcoming the limitations between the host interface and the peripherals, making the design more flexible.

[0038] In some optional implementations, in order to synchronously measure the excitation current signal on the Pack busbar based on the measurement of the excitation voltage signal of the battery cell, thereby providing data support for accurately grasping the relevant status of the battery, such as Figure 1As shown, in an embodiment of the present invention, a battery pack monitoring chip 500 is set between one end of the battery pack 100 and the main control chip 300. For example, the battery pack monitoring chip 500 is a Pack Monitor chip. At the same time, a shunt 600 is set between the Pack and the DC / DC module, which is represented by SHUNT. The battery pack monitoring chip 500 is connected at both ends of the shunt 600. When the current signal of the battery cell series bus passes through the shunt 600, a voltage is generated at both ends of the shunt 600, thereby facilitating the battery pack monitoring chip 500 to detect the excitation current signal according to the voltage data. The Pack Monitor chip is connected to the MCU via the SPI bus, and can transmit the excitation current signal collected on the Pack bus series shunt 600 to the MCU.

[0039] In some optional implementations, the embodiment of the present invention notifies the DC / DC module through a control signal by the MCU to generate excitation at a specific frequency, and performs switch chopping on the first switch tube 901 and the second switch tube 902 based on the specific frequency, which can convert the direct current generated by the voltage-stabilized power supply into alternating current, and generate an AC excitation signal on all series-connected battery cell buses, thereby generating an AC excitation signal on all series-connected battery cell buses and shunt buses, providing data for the realization of accurate battery status assessment. At the same time, the MCU outputs instructions to all AFE chips and Pack Monitor chips, which can synchronously collect the excitation voltage signal on the battery cell and the excitation current signal on the shunt, and confirm the current excitation DCDC frequency, and finally realize the synchronization of the excitation voltage and current analog signals on each battery cell at a specific frequency, and obtain the battery cell impedance (imaginary part, real part), excitation frequency, and the phase of the voltage and current of the battery cell under excitation. After performing frequency and time domain analysis, the MCU obtains the excitation data of each battery cell in the pack and passes the relevant data to the application layer. The application layer uses the algorithm model to analyze the electrochemical impedance spectrum of the battery cell to obtain the Nyquist spectrum. By comparing the Nyquist spectrum of the battery cell, the internal resistance, internal core temperature, SOC, SOH and other information of the battery cell are matched, thereby monitoring the health status of the battery cell in real time, identifying and screening outlier batteries in advance, and avoiding thermal runaway and preventing risks such as fire in advance by implementing strategic control measures such as power limiting and alarming in advance.

[0040] In some optional embodiments, the battery management system provided by the embodiments of the present invention can accurately obtain the SOC and SOH of the battery, and thus can accurately control the charging process based on SOC and SOH. On the one hand, it can accurately control the charging current according to the battery temperature, which is expected to shorten the charging time and improve the fast charging efficiency. On the other hand, it can widen the SOC correction range, solve the problems of mileage jump and the waiting time at the charging terminal, so as to ensure that the battery life is closer to the actual battery life, and the charging and discharging are closer to the actual capacity limit of the battery cell, reduce overheating and overcharging, significantly improve battery life, and improve user experience.

[0041] In some optional embodiments, such as Figure 1 As shown, the embodiment of the present invention deploys a battery 700 connected to a DC / DC module in the battery management system, such as a 12V BAT, which can transfer the energy generated during excitation to the battery 700. The battery 700 is usually located inside the engine hood, specifically in the upper right position, and is part of the vehicle's electrical system. Especially in hybrid electric vehicles, the replacement of this small battery is crucial for the normal starting of the vehicle. The battery 700 mainly supplies power to the vehicle's low-voltage electrical appliances, such as lights, speakers, radios, and other electronic control units (ECUs). Its voltage is generally around 12V, while commercial vehicles may be 24V. During the excitation generation process, the embodiment of the present invention can store energy and replenish the battery 700, thereby ensuring that the above-mentioned low-voltage electrical appliances can operate normally.

[0042] According to an embodiment of the present invention, on the other hand, a car is provided, comprising the above Figure 1 The battery management system shown.

[0043] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A battery management system, characterized in that: include: A battery pack (100) comprising a plurality of battery cells (101); a plurality of battery sampling chips (200) connected in a daisy chain series structure, wherein two ends of each battery sampling chip (200) are connected to two ends of the battery cell (101); a main control chip (300), wherein a first end of the main control chip (300) is connected to two ends of the battery sampling chip (200); a voltage-stabilized power supply (400), wherein a first end of the voltage-stabilized power supply (400) is connected to a second end of the main control chip (300), and a second end and a third end of the voltage-stabilized power supply (400) are respectively connected to two ends of the battery pack (100); A battery pack monitoring chip (500), wherein a first end of the battery pack monitoring chip (500) is connected to a third end of the main control chip (300), a second end of the battery pack monitoring chip (500) is connected to a first end of the battery pack (100), and a third end of the battery pack monitoring chip (500) is connected to a third end of the regulated power supply (400).

2. The system according to claim 1, wherein: Also includes: A shunt (600), wherein two ends of the shunt (600) are respectively connected to the second end and the third end of the battery pack monitoring chip (500).

3. The system according to claim 1, wherein: Also includes: A storage battery (700) is connected to the fourth end of the voltage-stabilized power supply (400).

4. The system according to claim 1, wherein: The number of the battery sampling chips (200) does not exceed the number of the battery cells (101), and each of the battery sampling chips (200) is connected to both ends of at least one of the battery cells (101).

5. The system according to claim 4, characterized in that The two battery sampling chips (200) at both ends of the series structure are connected to the first end of the main control chip (300) via a bridge chip (800).

6. The system according to claim 5, characterized in that The two battery sampling chips (200) at both ends of the series structure are respectively connected to the first end and the second end of the bridge chip (800) in a daisy chain topology; The third end of the bridge chip (800) is connected to the first end of the main control chip (300) via a full-duplex synchronous serial bus.

7. The system according to claim 1, wherein: The third end of the main control chip (300) is connected to the first end of the battery pack monitoring chip (500) via a full-duplex synchronous serial bus.

8. The system according to claim 1, wherein: The second end of the main control chip (300) is connected to the first end of the voltage-stabilized power supply (400) via a serial communication protocol bus.

9. The system according to claim 1, wherein: Also includes: A first switch tube (901) is provided on a connection line between the second end of the voltage-stabilized power supply (400) and the second end of the battery pack (100); The second switch tube (902) is provided on a connection line between the third end of the voltage-stabilized power supply (400) and the third end of the battery pack monitoring chip (500).

10. An automobile, characterized in that: A battery management system comprising the battery management system according to any one of claims 1 to 9.

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