Device for detecting high-voltage and low-voltage faults of battery in battery management system

Abstract

A battery high-low voltage fault detection device in a battery management system belongs to the technical field of battery management. Comprising an overvoltage detection circuit and an undervoltage detection circuit, the overvoltage detection circuit comprises a first battery overvoltage amplification circuit corresponding to a first battery and second to nth battery overvoltage amplification circuits corresponding to second to nth batteries respectively, the first battery overvoltage amplification circuit comprises a comparator U1B and a resistor R11, a pin 6 of the comparator U1B is connected with the first battery, and a pin 7 of the comparator U1B is connected with a pin 7 of the resistor R11. A pin 7 of the comparator U1B is connected with overvoltage fault alarm threshold voltage, one end of a resistor R11 is connected with a pin 1 of the comparator U1B, the other end of the resistor R11 is connected with a direct-current power supply VCC, the second battery overvoltage amplification circuit comprises a comparator U2C, a comparator U2D and resistors R21-R25, and a pin 8 of the comparator U2C is connected with a second battery. The device has the advantages that the fault information can be sent out even if the special battery management chip or the single-chip microcomputer is completely invalid, and the accuracy of fault detection is ensured.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the battery management technical field, specifically relates to a detection device of battery high and low voltage fault in battery management system. BACKGROUND

[0002] Lithium battery has the characteristics of small volume and light weight, and is widely used in mobile energy, but due to its own characteristics, when the battery is overcharged, the output voltage is higher than the rated voltage, and when the battery is insufficient, the output voltage is lower than the rated voltage, which not only affects the stable working state of the battery, but also causes damage to the electrical equipment, therefore, the voltage monitoring of the battery becomes particularly important.

[0003] Generally, the battery system is composed of multiple batteries in series, for example, a battery pack with a nominal voltage of 43.8V can be composed of 12 lithium batteries with a nominal voltage of 3.65V, at this time, the voltage of each of the 12 batteries needs to be monitored. The current common method is to add a battery management system circuit board in each battery pack, the circuit board usually uses a dedicated chip to collect the voltage data of the 12 batteries in real time, the chip generally has a SPI communication port, which can report the data to the single-chip microcomputer on the circuit board in real time, and the single-chip microcomputer generally has a field bus such as CAN / RS485 communication port, which can quickly transmit the battery voltage data to the upper management system, and the upper system can determine whether the battery is normal, and if not, take protective measures.

[0004] A typical battery management system is shown in FIG. Figure 1 Figure 1 The left side of the figure is 12 batteries in series, wherein V1-V12 represent the voltages of the 12 batteries to ground, and the dedicated battery management system chip U0 collects the voltages V1-V12 and sends the data to the single-chip microcomputer through the SPI communication port, and the single-chip microcomputer sends the data to the upper system through the field bus such as CAN. This typical battery management system is currently widely used in almost all electric vehicles and energy storage systems, and there is a certain risk: for example, when the dedicated battery management system chip U0 itself fails, it will not be able to collect real-time information of the battery, and the single-chip microcomputer may receive normal data at the past sampling point, at this time, when the battery voltage fails, it will not be able to correctly and timely sample the data; for another example, the single-chip microcomputer itself is an embedded system, which has hardware risks and software risks, if the single-chip microcomputer crashes or the single-chip microcomputer communication fails, the upper system will also not be able to correctly and timely collect the battery information, and there is a risk of hidden battery failure. The above risks make the battery management system have hidden fatal security vulnerabilities.

[0005] In view of the above prior art, the applicant has made a beneficial design, and the technical scheme to be introduced below is generated in this background. CONTENT OF THE UTILITY MODEL ​

[0006] The utility model discloses a battery management system battery high low voltage fault detection device can send out fault information even if special battery management chip or singlechip is completely inoperable, can guarantee the accuracy of battery fault detection.

[0007] The utility model discloses a battery management system battery high low voltage fault detection device, including special battery management system chip U0 and singlechip, special battery management system chip U0's input side connects n piece battery to be measured, singlechip is connected with special battery management system chip U0 through SPI communication, still connects the superior system through CAN communication, detection device still includes overvoltage detection circuit and undervoltage detection circuit, overvoltage detection circuit includes corresponding first battery overvoltage amplification circuit of 1st battery and respectively corresponding second to n battery overvoltage amplification circuit of 2nd to nth battery and same structure, wherein, n is the integer greater than 2, first battery overvoltage amplification circuit includes comparator U1B and resistance R11, and the 6 feet of comparator U1B connect 1st battery, and the 7 feet of comparator U1B connect overvoltage fault alarm threshold voltage, and one end of resistance R11 connects the 1 foot of comparator U1B, and the other end of resistance R11 connects direct current power supply VCC, second battery overvoltage amplification circuit includes comparator U2C, U2D and resistance R21~R25, and the 8 feet of comparator U2C connect 2nd battery, and the 9 feet of comparator U2C connect comparator U2D's 13 feet and one end of resistance R22, and the 11 feet of comparator U2D connect one end of resistance R24 and one end of resistance R25, and the other end of resistance R24 connects 1st battery, and the other end of resistance R25 connects overvoltage fault alarm threshold voltage, and the 10 feet of comparator U2D connect the other end of resistance R22 and one end of resistance R23, and the other end of resistance R23 connects ground, and one end of resistance R21 connects the 14 feet of comparator U2C, and the other end of resistance R21 connects direct current power supply VCC, and the n battery overvoltage amplification circuit including comparator UnC,UnD and resistance Rn1~Rn5 is connected with second battery overvoltage amplification circuit, and the 8 feet of comparator UnC connect nth battery, and the 9 feet of comparator UnC connect comparator UnD's 13 feet and one end of resistance Rn2, and the 11 feet of comparator UnD connect one end of resistance Rn4 and one end of resistance Rn5, and the other end of resistance Rn4 connects nth-1 battery, and the other end of resistance Rn5 connects overvoltage fault alarm threshold voltage, and the 10 feet of comparator UnD connect the other end of resistance Rn2 and one end of resistance Rn3, and the other end of resistance Rn3 connects ground, and one end of resistance Rn1 connects the 14 feet of comparator UnC, and the other end of resistance Rn1 connects direct current power supply VCC, and the 1 foot of comparator U1B and the 14 feet of comparator U2C,UnC are connected with superior system in common.

[0008] In one specific embodiment of the utility model, the under voltage detection circuit includes the first battery under voltage amplification circuit corresponding the first section battery and the second to N battery under voltage amplification circuit corresponding the second to n section battery respectively and the structure is same, wherein, n is the integer greater than 2, the first battery under voltage amplification circuit includes comparator U1 'B and resistance R11 ', the 7 foot of comparator U1 'B connects the first section battery, the 6 foot of comparator U1 'B connects under voltage fault alarm threshold voltage, one end of resistance R11'connects the 1 foot of comparator U1 'B, the other end of resistance R11'connects DC power supply VCC, the second battery under voltage amplification circuit includes comparator U2 'C, U2 'D and resistance R21 '-R25 ', the 9 foot of comparator U2 'C connects the second section battery, the 8 foot of comparator U2 'C connects the 13 foot of comparator U2 'D and one end of resistance R22 ', the 11 foot of comparator U2 'D connects one end of resistance R24'and one end of resistance R25 ', the other end of resistance R24'connects the first section battery, the other end of resistance R25'connects under voltage fault alarm threshold voltage, the 10 foot of comparator U2 'D connects the other end of resistance R22'and one end of resistance R23 ', the other end of resistance R23'connects ground, one end of resistance R21'connects the 14 foot of comparator U2 'C, the other end of resistance R21'connects DC power supply VCC, and the n battery under voltage amplification circuit includes comparator Un 'C, Un 'D and resistance Rn1 '-Rn5'same as the second battery under voltage amplification circuit, the 9 foot of comparator Un 'C connects the n section battery, the 8 foot of comparator Un 'C connects the 13 foot of comparator Un 'D and one end of resistance Rn2 ', the 11 foot of comparator Un 'D connects one end of resistance Rn4'and one end of resistance Rn5 ', the other end of resistance Rn4'connects the n-1 section battery, the other end of resistance Rn5'connects under voltage fault alarm threshold voltage, the 10 foot of comparator Un 'D connects the other end of resistance Rn2'and one end of resistance Rn3 ', the other end of resistance Rn3'connects ground, one end of resistance Rn1'connects the 14 foot of comparator Un 'C, the other end of resistance Rn1'connects DC power supply VCC, and the 1 foot of comparator U1 'B and the 14 foot of comparator U2 'C, Un 'C are connected to the upper system in common.

[0009] In another specific embodiment of the utility model, the comparator U1B, U2C, U2D, UnC, UnD, U1 'B, U2 'C, U2 'D, Un 'C, Un 'D all adopt LM339N.

[0010] The utility model discloses a new overvoltage detection circuit and under voltage detection circuit, compared with prior art, have beneficial effect is: can send out fault information even if special battery management chip or singlechip is completely inoperable, can safely and reliably real -time monitoring whether the voltage of each battery is overvoltage or under voltage, make the security and stability of battery system greatly improve, can inhibit the occurrence of battery accident. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is the hardware circuit schematic diagram of prior art battery management system;

[0012] Figure 2 It is the electric connection schematic diagram of overvoltage detection circuit in an embodiment of the utility model;

[0013] Figure 3 It is the electric connection schematic diagram of under voltage detection circuit in an embodiment of the utility model. DETAILED DESCRIPTION

[0014] The embodiment of the utility model is described in detail below in combination with the drawings, but the description of the embodiment is not the limitation of the technical scheme, and any form but not the substantial change according to the concept of the utility model should be regarded as the protection scope of the utility model.

[0015] In the following description, the directional (or directional) concept of up, down, left, right, front and back is for the position state of the figure being described, and the purpose is to facilitate the public to understand, so it cannot be understood as the special limitation of the technical scheme provided by the utility model.

[0016] See Figure 1 The utility model relates to a kind of detection devices of battery high-low voltage fault in battery management system, use the special battery management system chip U0 and singlechip in prior art, the input side of the special battery management system chip U0 is connected with n battery to be measured, 12 batteries are shown on the diagram, V1~V12 respectively indicate the voltage of the 12 batteries to ground.The singlechip is connected with the special battery management system chip U0 by SPI communication, and is also connected with the upper system by CAN communication.The singlechip reports the battery voltage data collected by the special battery management system chip U0 to the upper system.The technical scheme described in the utility model is adapted to different models of special battery management system chip U0 and singlechip, the special battery management system chip U0 can be ADBMS2950WCCSZ, and the singlechip can be STM32F107VCT6.

[0017] The technical key point of the utility model lies in Figure 1The overvoltage detection circuit and the undervoltage detection circuit are added on the basis of the prior art. The overvoltage detection circuit comprises a first battery overvoltage amplification circuit corresponding to the first battery and second to nth battery overvoltage amplification circuits corresponding to the second to nth batteries respectively and having the same structure. The undervoltage detection circuit comprises a first battery undervoltage amplification circuit corresponding to the first battery and second to nth battery undervoltage amplification circuits corresponding to the second to nth batteries respectively, wherein n is an integer greater than 2, and in the embodiment, n is 12, i.e., 12 lithium batteries with a nominal voltage of 3.65V are taken as an example for illustration. The overvoltage monitoring takes the voltage of a single battery exceeding 4.2V as the fault alarm voltage threshold, and the undervoltage monitoring takes the voltage of a single battery being lower than 2.5V as the fault alarm voltage threshold.

[0018] See Figure 2 The first battery overvoltage amplification circuit comprises a comparator U1B and a resistor R11. The pin 6 of the comparator U1B is connected to the first battery, the pin 7 of the comparator U1B is connected to the 4.2V overvoltage fault alarm threshold voltage, the pin 1 of the comparator U1B and one end of the resistor R11 are connected to the Vo point for common voltage output, the Vo point is connected to the upper system, and the other end of the resistor R11 is connected to the DC power supply VCC. The voltage V1 of the first battery is directly compared with the 4.2V input into the comparator U1B. If the voltage V1 is greater than 4.2V, the Vo point is at a low level, otherwise, the Vo point is at a high level due to being pulled up by the DC power supply VCC.

[0019] The second battery overvoltage amplification circuit comprises comparators U2C and U2D and resistors R21 to R25. The pin 8 of the comparator U2C is connected to the second battery. The pin 9 of the comparator U2C is connected to the pin 13 of the comparator U2D and one end of the resistor R22, the pin 11 of the comparator U2D is connected to one end of the resistor R24 and one end of the resistor R25, the other end of the resistor R24 is connected to the first battery, and the other end of the resistor R25 is connected to the 4.2V overvoltage fault alarm threshold voltage. The pin 14 of the comparator U2C and one end of the resistor R21 are connected to the Vo point, and the other end of the resistor R21 is connected to the DC power supply VCC. The voltage V2 of the second battery is compared with the V2_ref reference voltage on the pin 9 of the comparator U2C. The V2_ref reference voltage comes from the previous stage of the summing amplifier circuit. According to the knowledge of analog electricity, the value of the V2_ref reference voltage = V1 + 4.2V, so the V2_ref reference voltage is equivalent to being higher than V1 by 4.2V. The voltage at the upper end of the second battery is the voltage V1 of the first battery plus the voltage of the second battery. Therefore, if the voltage comparison between V2 and V2_ref exceeds 0V, it indicates that the voltage V2 of the second battery is higher than 4.2V.

[0020] Since the third to the twelfth battery overvoltage amplification circuits have the same structure as the second battery overvoltage amplification circuit, only the twelfth battery overvoltage amplification circuit is introduced here. The twelfth battery overvoltage amplification circuit includes comparators U12C and U12D and resistors R121-R125. The 8th pin of the comparator U12C is connected to the 12th battery, the 9th pin of the comparator U12C is connected to the 13th pin of the comparator U12D and one end of the resistor R122, the 11th pin of the comparator U12D is connected to one end of the resistor R124 and one end of the resistor R125, the other end of the resistor R124 is connected to the 11th battery, and the other end of the resistor R125 is connected to the 4.2V overvoltage fault alarm threshold voltage. The 14th pin of the comparator U12C is connected to the Vo point. In this embodiment, the comparators U1B, U2C, UnC, U2D and UnD all use LM339N.

[0021] Similarly to the second battery overvoltage amplification circuit, it can be concluded that the voltages V3-V12 of the third to the twelfth batteries can also be used to determine whether the voltages of the third to the twelfth batteries are overvoltage. When the output value of any comparator exceeds the threshold value, the Vo point voltage is pulled down, indicating a fault.

[0022] See Figure 3, the first battery under-voltage amplification circuit includes comparator U1'B and resistor R11', the 7-pin of comparator U1'B is connected with the first section battery, and the 6-pin of comparator U1'B is connected with the 2.5V under-voltage fault alarm threshold voltage. The second battery under-voltage amplification circuit includes comparators U2'C and U2'D and resistors R21'-R25', the 9-pin of comparator U2'C is connected with the second section battery, the 8-pin of comparator U2'C is connected with the 13-pin of comparator U2'D and one end of resistor R22', the 11-pin of comparator U2'D is connected with one end of resistor R24' and one end of resistor R25', the other end of resistor R24' is connected with the first section battery, and the other end of resistor R25' is connected with the 2.5V under-voltage fault alarm threshold voltage. Similarly with the second battery under-voltage amplification circuit, the twelfth battery under-voltage amplification circuit includes comparators U12'C and U12'D and resistors R121'-R125', the 9-pin of comparator U12'C is connected with the twelfth section battery, the 8-pin of comparator U12'C is connected with the 13-pin of comparator U12'D and one end of resistor Rn2', the 11-pin of comparator U12'D is connected with one end of resistor R124' and one end of resistor R125', the other end of resistor R124' is connected with the eleventh section battery, and the other end of resistor R125' is connected with the 2.5V under-voltage fault alarm threshold voltage. The 1-pin of comparator U1'B and the 14-pin of comparators U2'C and U12'C are commonly connected with Vo point. The comparators U1B, U2'C, U12'C, U2'D and U12'D all use LM339N. Similarly with the over-voltage amplification circuit principle, when the voltage of any section battery is lower than the threshold value 2.5V, Vo point voltage is pulled low, and fault is output.

[0023] In the above structure, the over-voltage or under-voltage of any section battery will cause Vo point low level, when Vo point high level, it indicates that all battery voltages are normal, the Vo point line and the GND point line are led out, and are connected with the single-chip microcomputer and the upper system, the working condition of the battery is judged through the hard line, even if the dedicated battery management chip or the single-chip microcomputer is completely disabled, the voltage of each section battery can be quickly and reliably monitored in real time to determine whether it is over-voltage or under-voltage, so that the safety of the battery system of the electric vehicle or the energy storage system is greatly improved, the fire risk of the electric vehicle or the energy storage system is controlled to the minimum level, and the occurrence of accidents is inhibited, so that the purpose is achieved.

Claims

1. A device for detecting high and low voltage faults of a battery in a battery management system, comprising a special battery management system chip U0 and a single-chip microcomputer, an input side of the special battery management system chip U0 being connected to n batteries to be detected, the single-chip microcomputer being connected to the special battery management system chip U0 through SPI communication and being connected to a superior system through CAN communication, characterized in that: The detection device further comprises overvoltage detection circuit and under-voltage detection circuit, the overvoltage detection circuit comprises the first battery overvoltage amplification circuit corresponding to the first section battery and the second to the n battery overvoltage amplification circuit corresponding to the second to the n section battery respectively and the same structure, wherein, n is the integer greater than 2, the first battery overvoltage amplification circuit comprises comparator U1B and resistance R11, the 6 feet of comparator U1B are connected with the first section battery, the 7 feet of comparator U1B are connected with overvoltage fault alarm threshold voltage, one end of resistance R11 is connected with the 1 feet of comparator U1B, the other end of resistance R11 is connected with DC power supply VCC, the second battery overvoltage amplification circuit comprises comparator U2C, U2D and resistance R21-R25, the 8 feet of comparator U2C are connected with the second section battery, the 9 feet of comparator U2C are connected with the 13 feet of comparator U2D and one end of resistance R22, the 11 feet of comparator U2D are connected with one end of resistance R24 and one end of resistance R25, the other end of resistance R24 is connected with the first section battery, the other end of resistance R25 is connected with overvoltage fault alarm threshold voltage, the 10 feet of comparator U2D are connected with the other end of resistance R22 and one end of resistance R23, the other end of resistance R23 is connected with ground, one end of resistance R21 is connected with the 14 feet of comparator U2C, the other end of resistance R21 is connected with DC power supply VCC, the n battery overvoltage amplification circuit is the same as the second battery overvoltage amplification circuit, the n battery overvoltage amplification circuit comprises comparator UnC, UnD and resistance Rn1-Rn5, the 8 feet of comparator UnC are connected with the n section battery, the 9 feet of comparator UnC are connected with the 13 feet of comparator UnD and one end of resistance Rn2, the 11 feet of comparator UnD are connected with one end of resistance Rn4 and one end of resistance Rn5, the other end of resistance Rn4 is connected with the n-1 section battery, the other end of resistance Rn5 is connected with overvoltage fault alarm threshold voltage, the 10 feet of comparator UnD are connected with the other end of resistance Rn2 and one end of resistance Rn3, the other end of resistance Rn3 is connected with ground, one end of resistance Rn1 is connected with the 14 feet of comparator UnC, the other end of resistance Rn1 is connected with DC power supply VCC, the 1 feet of comparator U1B and the 14 feet of comparator U2C, UnC are connected with the upper system. ​ 2. The device for detecting high and low voltage faults of a battery in a battery management system according to claim 1, characterized in that: The under-voltage detection circuit comprises a first battery under-voltage amplification circuit corresponding to the first battery and second to Nth battery under-voltage amplification circuits corresponding to the second to Nth batteries respectively and having the same structure. The first battery under-voltage amplification circuit comprises a comparator U1'B and a resistor R11'. The pin 7 of the comparator U1'B is connected to the first battery, the pin 6 of the comparator U1'B is connected to an under-voltage fault alarm threshold voltage, one end of the resistor R11' is connected to the pin 1 of the comparator U1'B, and the other end of the resistor R11' is connected to a direct current power supply VCC. The second battery under-voltage amplification circuit comprises comparators U2'C and U2'D and resistors R21' to R25'. The pin 9 of the comparator U2'C is connected to the second battery, the pin 8 of the comparator U2'C is connected to the pin 13 of the comparator U2'D and one end of the resistor R22', the pin 11 of the comparator U2'D is connected to one end of the resistor R24' and one end of the resistor R25', the other end of the resistor R24' is connected to the first battery, the other end of the resistor R25' is connected to the under-voltage fault alarm threshold voltage, the pin 10 of the comparator U2'D is connected to the other end of the resistor R22' and one end of the resistor R23', the other end of the resistor R23' is connected to ground, one end of the resistor R21' is connected to the pin 14 of the comparator U2'C, and the other end of the resistor R21' is connected to the direct current power supply VCC. The Nth battery under-voltage amplification circuit comprises comparators Un'C and Un'D and resistors Rn1' to Rn5', which are the same as the second battery under-voltage amplification circuit. The pin 9 of the comparator Un'C is connected to the Nth battery, the pin 8 of the comparator Un'C is connected to the pin 13 of the comparator Un'D and one end of the resistor Rn2', the pin 11 of the comparator Un'D is connected to one end of the resistor Rn4' and one end of the resistor Rn5', the other end of the resistor Rn4' is connected to the (N-1)th battery, the other end of the resistor Rn5' is connected to the under-voltage fault alarm threshold voltage, the pin 10 of the comparator Un'D is connected to the other end of the resistor Rn2' and one end of the resistor Rn3', the other end of the resistor Rn3' is connected to ground, one end of the resistor Rn1' is connected to the pin 14 of the comparator Un'C, and the other end of the resistor Rn1' is connected to the direct current power supply VCC. The pin 1 of the comparator U1'B and the pin 14 of the comparators U2'C and Un'C are connected to a higher-level system.

3. The device for detecting high and low voltage faults of a battery in a battery management system according to claim 2, characterized in that: The comparators U1B, U2C, U2D, UnC, UnD, U1'B, U2'C, U2'D, Un'C and Un'D are all LM339N.

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