A battery management system

Abstract

The utility model discloses a kind of battery management systems, the temperature acquisition module of this system includes at least one multiplexer and multiple temperature acquisition circuits corresponding one-to-one with single battery;Multiple analog channel pins of multiplexer are connected with a temperature acquisition circuit respectively, three address ends are connected with the three general digital output pin of MCU, common end is connected with the ADC pin of MCU, temperature acquisition circuit is also connected with corresponding single battery connection.The utility model realizes the extension of temperature acquisition channel by multiplexer, without extra occupying the ADC pin resource of MCU, can be flexibly adapted to the scene of the increase of single battery quantity, reduces hardware resource occupancy and circuit design complexity, guarantees the accuracy of temperature acquisition, improves the scalability and reliability of battery management system, and is applicable to the safe and efficient management of coal mine underground UPS power battery pack.

Description

Technical Field

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

[0002] In underground coal mine operations, to ensure continuous power supply, UPS power supplies typically use multiple rechargeable individual batteries connected in series to form a battery pack as a backup power source to meet emergency power needs after a mains power outage. To ensure the safe and efficient operation of the battery pack under complex operating conditions, a Battery Management System (BMS) is required to monitor and manage battery performance in real time. Temperature acquisition is one of the core functions of the BMS—by accurately collecting the temperature of each individual battery cell, potential safety hazards such as overheating and abnormal temperature differences can be detected in a timely manner, preventing battery pack failures caused by thermal runaway and ensuring the stability of the underground power supply system.

[0003] In existing technologies, BMS temperature acquisition modules mostly adopt a "one-to-one" or "fixed-channel" hardware design, meaning that the temperature acquisition circuit of each individual battery is directly connected to the ADC pin of the microcontroller (MCU). However, with changes in the power load in coal mines, the number of individual batteries in the UPS battery pack often needs to be increased according to actual needs (such as expanding power supply capacity or extending backup time). At this time, existing temperature acquisition modules expose the problem of poor scalability: on the one hand, the number of ADC pins of the MCU is limited, and adding an individual battery requires additional pin resources, resulting in the need to redesign the hardware circuit; on the other hand, the fixed-channel acquisition circuit is difficult to adapt to scenarios with different numbers of individual batteries, requiring frequent adjustments to the circuit structure, increasing system development costs and maintenance difficulty, and may even affect the temperature monitoring accuracy of the battery pack due to adaptation delays, threatening the safety of underground power supply.

[0004] Therefore, to address the insufficient adaptability of existing BMS temperature acquisition modules in scenarios with an increased number of individual batteries, there is an urgent need for a temperature acquisition solution that is flexibly expandable and has low hardware resource consumption, in order to improve the adaptability of BMS to battery packs of different sizes and ensure the reliable operation of UPS power supplies in coal mines. Utility Model Content

[0005] Based on this, a battery management system is provided to address the aforementioned technical problems.

[0006] The technical solution adopted in this utility model is as follows:

[0007] A battery management system includes a temperature acquisition module for collecting the temperature of each individual cell in a battery pack and transmitting it to an MCU. The temperature acquisition module comprises at least one multiplexer and multiple temperature acquisition circuits corresponding to each individual cell. Multiple analog channel pins of the multiplexer are respectively connected to one of the temperature acquisition circuits. The three address pins of the multiplexer are connected to the three general-purpose digital output pins of the MCU, and the common pin of the multiplexer is connected to the ADC pin of the MCU. The temperature acquisition circuits are also connected to the corresponding individual cells.

[0008] The beneficial effects of this utility model are as follows:

[0009] 1. Significantly improves the scalability of the temperature acquisition module, adapting to scenarios where the number of individual battery cells can be dynamically adjusted.

[0010] The temperature acquisition module adopts an architecture of "multiplexer + independent temperature acquisition circuit". Multiple analog channel pins of the multiplexer are connected to a temperature acquisition circuit corresponding to a single battery cell. The MCU can select different temperature acquisition circuits by controlling the address pins of the multiplexer (connected to a general-purpose digital output pin), enabling the acquisition of the temperature of any single battery cell. When the number of single batteries increases, only the number of multiplexers needs to be increased or multiplexers with more channels (such as 8-channel, 16-channel, etc.) need to be selected. This expands the temperature acquisition channels without occupying additional MCU ADC pin resources, effectively solving the problem of poor scalability caused by pin limitations in existing modules, allowing the BMS to flexibly adapt to battery packs of different sizes.

[0011] 2. Reduce hardware resource consumption and simplify circuit design.

[0012] Traditional temperature acquisition modules require an independent ADC channel for each individual battery cell, leading to a shortage of MCU pin resources. This invention connects the common terminal of a multiplexer to a single ADC pin of the MCU. Signals from all temperature acquisition circuits share a single ADC channel after being selected by the multiplexer, significantly reducing the occupation of MCU hardware pins, lowering the complexity of circuit design and hardware costs. It is especially suitable for scenarios in coal mines where there are strict requirements for equipment miniaturization and low power consumption.

[0013] 3. Ensure the accuracy and relevance of temperature data acquisition, and improve the reliability of BMS management.

[0014] The temperature acquisition circuit corresponds one-to-one with each individual battery, and can independently acquire the temperature signal of each battery, avoiding signal interference or errors caused by the traditional "shared acquisition circuit". Combined with the precise gating control of the multiplexer, the MCU can acquire the temperature data of each individual battery in real time and accurately, providing a reliable basis for functions such as battery equalization and over-temperature protection, and further ensuring the safe and efficient operation of the battery pack in the complex environment of underground coal mines.

[0015] 4. When the battery pack configuration is adjusted (such as adding a single battery cell), only the multiplexer channels need to be expanded or the number of modules increased. There is no need to make large-scale modifications to the core circuit, which improves the practicality and durability of the BMS in the downhole environment. Attached Figure Description

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0017] Figure 1 A schematic diagram of a battery management system provided for an embodiment of this utility model;

[0018] Figure 2 This is a schematic diagram of a multiplexer according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the temperature acquisition circuit according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the reference voltage generation circuit according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the MCU according to an embodiment of the present utility model;

[0022] Figure 6 This is a schematic diagram of the front-end chip in an embodiment of the present utility model;

[0023] Figure 7 This is a schematic diagram of the first peripheral circuit of an embodiment of the present utility model;

[0024] Figure 8 This is a schematic diagram of the second peripheral circuit according to an embodiment of the present invention;

[0025] Figure 9 A schematic diagram of the relevant structure of the EG1192L power supply module, which is the power supply module of this utility model embodiment;

[0026] Figure 10 A schematic diagram of the relevant structure of the SCT2601 power supply module in an embodiment of this utility model;

[0027] Figure 11This is a schematic diagram of the discharge control circuit according to an embodiment of the present invention;

[0028] Figure 12 This is a schematic diagram of the charging control circuit according to an embodiment of the present invention. Detailed Implementation

[0029] The embodiments of this utility model will be described below with reference to the accompanying drawings. It should be noted that the embodiments described in this specification are not exhaustive and do not represent the only embodiments of this utility model. The following corresponding embodiments are only for clearly illustrating the utility model content of this patent and are not intended to limit its implementation. For those skilled in the art, different variations and modifications can be made based on the described embodiments. Any obvious variations or modifications that fall within the technical concept and utility model content of this utility model are also within the protection scope of this utility model.

[0030] like Figure 1 As shown in the figure, this application provides a battery management system, including a temperature acquisition module 11, an MCU 12, a front-end chip 13, and a power supply module 14.

[0031] The temperature acquisition module 11 is used to acquire the temperature of each individual cell in the battery pack and send it to the MCU. It includes at least one multiplexer and multiple temperature acquisition circuits corresponding to each individual cell.

[0032] In this embodiment, as Figure 2 As shown, the multiplexer uses the CD4051BM96 chip, which has eight analog channel pins T1-T8, three address terminals A, B, and C, and a common terminal COM. Each of the eight analog channel pins T1-T8 is connected to a temperature acquisition circuit, allowing for the acquisition of eight temperature channels. In practical applications, more CD4051BM96 chips can be added to acquire more temperature channels, providing convenient expansion. The three address terminals A, B, and C are connected to the three general-purpose digital output pins of the MCU, and the common terminal COM is connected to the MCU's ADC pin. (See [link to relevant documentation]). Figure 5 .

[0033] The temperature acquisition circuit is also connected to the corresponding individual battery cell. In this embodiment, as shown... Figure 3 As shown, taking the temperature acquisition circuit connected to the analog channel pin T1 as an example, it includes a temperature sensor (resistor R4), resistor R5 and resistor R6. One end of resistor R4 is connected to the corresponding single cell, one end of resistor R5 and one end of resistor R6. The other end of resistor R4 is connected to the corresponding analog channel pin T1. The other end of resistor R5 is connected to the 3.3V reference voltage Vref. The other end of resistor R6 is grounded. Capacitor C1 acts as a filter.

[0034] The CD4051BM96 chip can calculate a corresponding voltage value U based on a 3.3V reference voltage Vref. 测 Based on the voltage value U and the resistance values ​​of R5 and R6, the resistance value of the temperature sensor R4 can be obtained, and thus the corresponding temperature value can be obtained. The calculation formula is as follows:

[0035] U 测 =3.33*R6*R4 / (R6*R4+R5*R6+R4*R5).

[0036] The three general-purpose digital output pins of the MCU12 can control the selection of eight analog channel pins T1-T8 of the CD4051BM96 chip by outputting high and low levels. This allows the CD4051BM96 chip to acquire eight temperature values. After obtaining the temperature values, the CD4051BM96 chip uploads them to the MCU12 via the common terminal COM. See [link to relevant documentation]. Figure 5 .

[0037] Figure 4 The reference voltage generation circuit is shown. In this embodiment, the TL431 chip outputs a 3.3V reference voltage Vref to the temperature acquisition circuit. The anode of the TL431 chip is grounded. The reference terminal is connected to the cathode and ground through voltage divider resistors R1 and R2, respectively. The cathode is connected to the input voltage (12V) through the current-limiting resistor R3. The cathode also outputs a 3.3V reference voltage Vref to resistor R5. The TL431 chip has extremely high temperature stability, ensuring that the temperature sampling accuracy is within ±1℃ error range.

[0038] like Figure 5 As shown, MCU12 communicates with the front-end chip via I2C (the communication is to upload the battery pack data collected by the BMS to the upper end via 485), and it also has High T pin and Low T pin for outputting over-temperature signal and low-temperature signal respectively.

[0039] The MCU12 determines whether the temperature is too high or too low based on the temperature value uploaded by the multiplexer. If the temperature is too high, the HighT pin outputs a high level, and under normal conditions, it outputs a low level. If the temperature is too low, the LowT pin outputs a low level, and under normal conditions, it outputs a high level.

[0040] like Figure 6 As shown, the front-end chip 13 is powered by a dual-loop system, either from a battery pack or an external power supply, and has multiple voltage acquisition pins B0 to B1. n The system includes a first resistance value acquisition pin T1, a second resistance value acquisition pin T2, and a first control signal pin CHG and a second control signal pin DSG, which are used to output charging control signals and discharging control signals, respectively.

[0041] In this embodiment, there are 17 voltage acquisition pins, which are respectively connected to the voltage nodes B1- to Bn+ of the battery pack to acquire the voltage of each individual cell in the battery pack. Based on the voltage conditions, charging control signals and discharging control signals can be output to the outside world through the first control signal pin CHG and the second control signal pin DSG.

[0042] The first resistance acquisition pin T1 and the second resistance acquisition pin T2 are respectively connected to the first peripheral circuit and the second peripheral circuit.

[0043] like Figure 7 As shown, the first peripheral circuit includes a first BJT transistor BJT1, resistors R7 and R8. The gate of the first BJT transistor BJT1 is connected to the Low T pin, the source is grounded, and the drain is connected to one end of resistor R7 and one end of resistor R8. The other end of resistor R7 is connected to the first resistance value acquisition pin T1, and the other end of resistor R8 is grounded. The current-limiting resistor R9 limits the current to the gate, and resistor R10 is used to discharge static electricity between the gate and the source.

[0044] like Figure 8 As shown, the second peripheral circuit includes a second BJT transistor BJT2, resistors R11 and R12. The gate of the second BJT transistor BJT2 is connected to the High T pin, the source is grounded, and the drain is connected to one end of resistor R11. The other end of resistor R11 is connected to the second resistance value acquisition pin T2. ​​One end of resistor R12 is connected to the second resistance value acquisition pin T2, and the other end is grounded. Current limiting R13 limits the current to the gate, and resistor R14 releases the static electricity between the gate and the source.

[0045] In this embodiment, the low temperature protection value of the front-end chip 13 is 0°C, and the over-temperature protection value is 50°C (the protection value can be modified by the host computer of the front-end chip).

[0046] When the Low T pin outputs a low level, the DS terminals (source and drain) of the first BJT transistor BJT1 are not conducting. The resistance value sampled by T1 is 40KΩ (the sum of the resistance values ​​of resistors R7 and R8). According to the temperature sensor model 3950, the corresponding temperature is -4℃, which is lower than the low temperature protection temperature value. The CHG and DSG pins of the front-end chip 13 will output control signals to prohibit charging and discharging. Under normal conditions, the Low T pin outputs a high level, the DS terminals of the first BJT transistor BJT1 are conducting, and the resistance sampled by T1 is 20KΩ (the resistance value of resistor R7). According to the temperature sensor model 3950, the corresponding temperature is 9℃, which is normal.

[0047] The High T pin outputs a high level, and the DS terminal of the second BJT transistor BJT2 is turned on. The resistance value measured by T2 is 2.2KΩ (resistance value of resistor R11). According to the temperature sensor model 3950, the corresponding temperature is 63℃, which is higher than the high temperature protection temperature value. The CHG and DSG pins of the front-end chip 13 output control signals to prohibit charging and discharging. Under normal conditions, the High T pin outputs a low level, and the DS terminal of the second BJT transistor BJT2 is not turned on. The resistance value measured by T2 is 10KΩ (resistance value of resistor R12). According to the temperature sensor model 3950, the corresponding temperature is 25℃, which is normal.

[0048] As can be seen, the protection and control of battery pack voltage and temperature are all completed by the front-end chip, which reduces the use of MCU peripheral ports and reduces the amount of embedded software control logic to be written.

[0049] It should be noted that the software programs in the temperature acquisition module 11, MCU 12 and front-end chip 13 (temperature acquisition module 11 calculates the temperature, MCU 12 judges over-temperature or under-temperature and front-end chip 13 judge over-temperature or under-temperature) are all existing conventional programs.

[0050] The power supply module 14 includes an EG1192L power supply module and an SCT2601 power supply module. The EG1192L power supply module provides a 12V power supply voltage to the reference voltage generation circuit and the SCT2601 power supply module, while the SCT2601 power supply module provides a 3.3V power supply voltage to the multiplexer and the MCU.

[0051] Specifically, such as Figure 9 As shown, the EG1192L power module has an input voltage range of DC10V-100V, providing wide-range power supply and ensuring normal power supply even when the number of individual battery cells in the battery pack increases. Its VIN is powered by a dual-circuit supply from the battery pack or an external power source. Capacitors C1 and C2 are input filter capacitors, and resistor R16 is the current-limiting resistor for the EG1192L power module. This chip has overcurrent protection. The output voltage of the EG1192L power module is only used to control the external charge / discharge controller and power the board; there will be no overload behavior. Resistor R16 can be used to limit the current. The resistance value of R16 should be chosen as low as possible. Resistor R16 is used to set the overcurrent protection value of the EG1192L power module. The bootstrap capacitor C4, freewheeling diode D1, and inductor L1 form the input high-frequency circuit section to address heat dissipation and copper plating issues in the design. Resistors R17, R18, and R19 form a feedback voltage divider circuit to adjust the output voltage to 12V. Capacitors C6, C7, and C8 are output filter capacitors to filter the output DC12V. Resistor R20 provides a dummy load for the output to ensure circuit stability. Capacitor C5 is used for output filtering.

[0052] like Figure 10As shown, the SCT2601 power module has a power consumption of 80uA, making it suitable for low-power design of the board. Its VIN pin input voltage is provided by the 12V output of the EG1192L power module; the EN enable pin receives voltage through voltage divider resistor R23 to ensure module startup; L2 is an energy storage inductor; capacitors C10 and C11 are output decoupling filter capacitors to ensure a stable 3.3V output voltage; resistors R21 and R22 are connected to the FB feedback pin, and a 3.3V voltage is obtained through feedback voltage division; capacitor C9 is used to eliminate the influence of reverse surge current on the chip.

[0053] In this embodiment, the temperature acquisition module 11, MCU 12, front-end chip 13 and power supply module 14 are set on the same circuit board. In conjunction with the external charge and discharge controller, the control signals output by pins CHG and DSG are sent to the external charge and discharge controller, which then performs the control and protection of the battery pack charging and discharging, ensuring that the current on the circuit board is not too high, reducing the heat generation of the circuit board and lowering the failure rate.

[0054] The voltage of the control signals output from pins CHG and DSG can be changed by replacing the feedback resistors (resistors R17, R18, and R19) of the EG1192L power module. This allows for the control of external charge / discharge controllers requiring different voltage levels, making it highly versatile. A specific example is shown below.

[0055] Figure 11 The discharge control circuit is shown. Taking the EG1192L power module outputting DC12V voltage as an example, when the front-end chip does not have discharge protection, its pin DSG outputs a high-level signal, forming a conduction voltage difference between the gate and source of Q41, and the drain and source are conducting. This causes the gate and source of T20 to form a conduction voltage, and the drain and source are conducting. FD+ outputs DC12V to the external charge and discharge controller (which can be a relay or DC contactor) to discharge the battery pack. When the front-end chip performs discharge protection, the pin DSG outputs a low level, the gate and source of Q41 do not form a conduction voltage, and the source and drain are not conducting. This causes the gate and source of T20 to not form a conduction voltage, and the drain and source are not conducting. FD+ outputs 0V to the external charge and discharge controller to prevent the battery pack from discharging.

[0056] Among them, F1 is a self-resetting fuse that provides overcurrent protection. You can choose a fuse with an appropriate overcurrent protection trip current value as needed; D20 is used to set a stable clamping voltage between the gate and source to cope with forward and reverse overvoltage (you can choose a suitable Zener diode as needed); C90 is used for filtering; R92 is used to release the static electricity generated between the gate and source of T20; R279 is a current limiting resistor; R89 is used to release the static electricity generated between the gate and source of Q41; D5 is used to prevent reverse voltage.

[0057] Figure 12 The charging control circuit is shown. Taking the EG1192L power module outputting DC12V voltage as an example, when the front-end chip has no charging protection, the CHG pin outputs a high-level signal. A voltage difference is formed between the gate and source of Q43, and the drain and source are conducting. This results in no voltage difference between the gate and source of Q42, thus no voltage difference between the drain and source of T21. T21 is not conducting, and CD+ outputs 0V voltage to the external charge / discharge controller to charge the battery pack. When the front-end chip performs charging protection, the CHG pin outputs a low level. There is no voltage difference between the gate and source of Q43, and the drain and source are not conducting. This results in a voltage difference being formed between the gate and source of Q42, and the drain and source are conducting. This results in a voltage difference being formed between the gate and source of T21, and the drain and source are conducting. CD+ outputs DC12V to the external charge / discharge controller to prevent the battery pack from charging.

[0058] For the functions of other components, please refer to the discharge control circuit.

[0059] As can be seen, the external charge and discharge controller mentioned above requires a voltage level of 12V. Of course, if the external charge and discharge controller requires a voltage level of 24V, the feedback resistor of the EG1192L power module can be replaced to make it output a voltage of 24V.

[0060] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A battery management system, comprising a temperature acquisition module for collecting the temperature of each individual cell in a battery pack and transmitting it to an MCU, characterized in that, The temperature acquisition module includes at least one multiplexer and multiple temperature acquisition circuits corresponding to each individual battery cell. The multiple analog channel pins of the multiplexer are respectively connected to one of the temperature acquisition circuits. The three address terminals of the multiplexer are connected to the three general-purpose digital output pins of the MCU. The common terminal of the multiplexer is connected to the ADC pin of the MCU. The temperature acquisition circuit is also connected to the corresponding individual battery cell.

2. The battery management system according to claim 1, characterized in that, The multiplexer is a CD4051BM96 chip.

3. The battery management system according to claim 1, characterized in that, The temperature acquisition circuit includes a temperature sensor, resistor R5, and resistor R6. One end of the temperature sensor is connected to the corresponding single cell, one end of resistor R5, and one end of resistor R6. The other end of the temperature sensor is connected to the corresponding analog channel pin. The other end of resistor R5 is connected to a reference voltage, and the other end of resistor R6 is grounded.

4. A battery management system according to claim 3, characterized in that, It also includes a TL431 chip for outputting a reference voltage to the temperature acquisition circuit. The anode of the TL431 chip is grounded, and the reference terminal is connected to the cathode and ground through voltage divider resistors R1 and R2, respectively. The cathode is connected to the input voltage through current limiting resistor R3, and the cathode is also connected to resistor R5.

5. A battery management system according to claim 1, characterized in that, The MCU has a High T-pin and a Low T-pin for outputting over-temperature and low-temperature signals, respectively. The battery management system also includes a front-end chip. The front-end chip has multiple voltage acquisition pins connected to the voltage nodes of the battery pack, a first resistance acquisition pin, a second resistance acquisition pin, and a first control signal pin and a second control signal pin for outputting charging and discharging control signals, respectively. The first and second resistance acquisition pins are respectively connected to a first peripheral circuit and a second peripheral circuit. The first peripheral circuit includes a first BJT transistor, resistor R7, and resistor R8. The gate of the first BJT transistor is connected to the Low T-pin. The high-T pin is connected, the source is grounded, and the drain is connected to one end of resistor R7 and one end of resistor R8. The other end of resistor R7 is connected to the first resistance value acquisition pin, and the other end of resistor R8 is grounded. The second peripheral circuit includes a second BJT transistor, resistor R11, and resistor R12. The gate of the second BJT transistor is connected to the high-T pin, the source is grounded, and the drain is connected to one end of resistor R11. The other end of resistor R11 is connected to the second resistance value acquisition pin, and one end of resistor R12 is connected to the second resistance value acquisition pin, while the other end is grounded.

6. A battery management system according to claim 5, characterized in that, It also includes a power supply module, which includes an EG1192L power supply module and an SCT2601 power supply module. The EG1192L power supply module provides power supply voltage to the SCT2601 power supply module, and the SCT2601 power supply module provides power supply voltage to the multiplexer, MCU and front-end chip.

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