Battery cell voltage sampling detection circuit, battery management system and electric vehicle

Abstract

The utility model provides a cell voltage sampling detection circuit, a battery management system and an electric vehicle. The circuit comprises a voltage acquisition sub-circuit, a detection sub-circuit and a processing sub-circuit. The voltage acquisition sub-circuit is respectively connected with each battery cell in the battery module, the input end of the detection sub-circuit is respectively connected to a sampling line between the voltage acquisition sub-circuit and each battery cell, and the output end of the detection sub-circuit is connected with the processing sub-circuit; the voltage acquisition sub-circuit is used for acquiring the battery cell voltage of each battery cell; the detection sub-circuit is used for comparing battery cell voltages on the sampling lines on the two sides of each battery cell, and outputting broken line state signals corresponding to the sampling lines on the two sides of each battery cell to the processing sub-circuit after voltage isolation conversion; and after the processing sub-circuit receives the broken line state signal, the sampling line on-off state of each battery cell is obtained according to the level state of the broken line state signal. According to the scheme provided by the utility model, the reliability and the safety of a cell voltage sampling link are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery management, in particular to a cell voltage sampling and detecting circuit, a battery management system and an electric vehicle. Background Art

[0002] With the increase of the cruising range of electric vehicles, the requirement for the energy density of the battery pack is gradually increasing, and the working safety and stability of the battery pack are also more prominent. At present, an Analog Front End (AFE) chip is usually used to collect key state signals such as cell voltage, so as to monitor the working state of the battery pack in real time.

[0003] In the related art, in the cell voltage sampling link, multiple sampling channels are set according to the cell distribution. If one or several sampling lines in the multiple sampling channels are broken, the accuracy of the voltage sampling result will be affected. At the same time, the damaged sampling channel will also have the problem of increased power consumption. Since the analog front end chip takes power from the cell voltage, the increased channel power consumption will affect the working stability of the cell.

[0004] However, there is currently no effective solution for detecting the damage condition of the sampling line and the position of the damaged channel, so that the accuracy and safety of the cell voltage sampling link are both low. Summary of the Utility Model

[0005] The utility model provides a cell voltage sampling and detecting circuit, a battery management system and an electric vehicle, so as to solve the defect that it is difficult to effectively detect the damage condition of the sampling line and the position of the damaged channel in the cell voltage sampling link.

[0006] On the one hand, the utility model provides a cell voltage sampling and detecting circuit, including: a voltage acquisition sub-circuit, a detection sub-circuit and a processing sub-circuit;

[0007] The voltage acquisition sub-circuit is respectively connected to each cell in the battery module. The input end of the detection sub-circuit is respectively connected to the sampling lines between the voltage acquisition sub-circuit and each cell, and the output end of the detection sub-circuit is connected to the processing sub-circuit;

[0008] The voltage acquisition sub-circuit is used to acquire the cell voltage of each cell;

[0009] The detection sub-circuit is used to compare the cell voltages on the sampling lines on both sides of each cell, and after voltage isolation conversion, output the disconnection state signal corresponding to the sampling lines on both sides of each cell to the processing sub-circuit;

[0010] After receiving the disconnection state signal, the processing sub-circuit obtains the on-off state of the sampling line of each cell according to the level state of the disconnection state signal.

[0011] According to the cell voltage sampling and detection circuit provided by the present utility model, the detection sub-circuit includes: a voltage comparison module and an isolation output module;

[0012] The input ends of the voltage comparison module are respectively connected to the sampling lines between the voltage acquisition sub-circuit and each cell, the output end of the voltage comparison module is connected to the isolation output module, and the isolation output module is also connected to the processing sub-circuit;

[0013] The voltage comparison module is used to compare the cell voltages on the sampling lines on both sides of each cell, and output the comparison result signals corresponding to the sampling lines on both sides of each cell to the isolation output module;

[0014] The isolation output module is used to perform voltage isolation conversion according to each comparison result signal, and output a disconnection state signal to the processing sub-circuit.

[0015] According to the cell voltage sampling and detection circuit provided by the present utility model, the voltage comparison module includes multiple voltage dividing and comparing units, and the set number of the voltage dividing and comparing units is the same as the number of cells;

[0016] The voltage dividing and comparing unit includes: a first voltage dividing resistor, a second voltage dividing resistor, and a voltage comparator;

[0017] The first end of the first voltage resistor and the first end of the second voltage dividing resistor are respectively connected to the sampling lines between the voltage acquisition sub-circuit and the corresponding cell on both sides, the second end of the first voltage dividing resistor is connected to the non-inverting input end of the voltage comparator, the second end of the second voltage dividing resistor is connected to the inverting input end of the voltage comparator, and the output end of the voltage comparator is connected to the isolation output module.

[0018] According to the cell voltage sampling and detection circuit provided by the present utility model, the voltage dividing and comparing unit further includes: a current limiting resistor;

[0019] The current limiting resistor is respectively connected to the output end of the voltage comparator and the isolation output module.

[0020] According to the cell voltage sampling and detection circuit provided by the present utility model, the voltage dividing and comparing unit further includes: an anti-reverse diode;

[0021] The positive electrode of the anti-reverse diode is connected to the output end of the voltage comparator, and the negative electrode of the anti-reverse diode is connected to the isolation output module.

[0022] According to the cell voltage sampling and detection circuit provided by the present utility model, the isolation output module includes multiple optocoupler isolation units, and the set number of the optocoupler isolation units is the same as the number of cells;

[0023] The optocoupler isolation unit includes: an optocoupler switch and a triode;

[0024] The base of the triode is connected to the output terminal of the voltage comparison module, the collector of the triode is connected to the optocoupler switch, the emitter of the triode is connected to the high-voltage area ground terminal, and the optocoupler switch is also connected to the processing sub-circuit.

[0025] According to the cell voltage sampling and detection circuit provided by the present invention, the optocoupler isolation unit further includes: a third voltage dividing resistor, a fourth voltage dividing resistor, a fifth voltage dividing resistor, and a sixth voltage dividing resistor;

[0026] The first end of the third voltage dividing resistor is connected to the high-voltage area power supply, the first end of the fourth voltage dividing resistor is connected to the low-voltage area power supply, the first end of the fifth voltage dividing resistor is connected to the low-voltage area ground terminal, the second ends of the third voltage dividing resistor, the fourth voltage dividing resistor, and the fifth voltage dividing resistor are all connected to the optocoupler switch, and the sixth voltage dividing resistor is respectively connected to the emitter of the triode and the high-voltage area ground terminal.

[0027] According to the cell voltage sampling and detection circuit provided by the present invention, the processing sub-circuit includes: a processing chip and a power management chip;

[0028] The processing chip is respectively connected to the output terminal of the detection sub-circuit and the wake-up pin of the power management chip;

[0029] After receiving the disconnection state signal, the processing chip obtains the on / off state of the sampling line of each cell according to the level state of the disconnection state signal, and outputs a wake-up signal to the power management chip when detecting that the level state of the disconnection state signal is the target state.

[0030] On the other hand, the present invention also provides a battery management system, including any one of the above-mentioned cell voltage sampling and detection circuits.

[0031] On the other hand, the present invention also provides an electric vehicle, including any one of the above-mentioned cell voltage sampling and detection circuits or the above-mentioned battery management system.

[0032] The cell voltage sampling and detection circuit, battery management system, and electric vehicle provided by the present utility model cooperate through a voltage acquisition sub-circuit, a detection sub-circuit, and a processing sub-circuit. Based on the voltage acquisition sub-circuit collecting the cell voltage of each cell, the detection sub-circuit compares the cell voltages on the sampling lines on both sides of each cell, and after voltage isolation and conversion, outputs the disconnection state signals corresponding to the sampling lines on both sides of each cell to the processing sub-circuit. The processing sub-circuit obtains the on-off state of the sampling line of each cell according to the level state of the disconnection state signal, thereby effectively detecting the damage conditions and damaged channel positions of each sampling line in the cell voltage sampling link, and improving the reliability and safety of the cell voltage sampling link. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 is one of the structural schematic diagrams of the cell voltage sampling and detection circuit provided by the embodiment of the present utility model;

[0035] Figure 2 is the circuit structural schematic diagram of the voltage acquisition sub-circuit;

[0036] Figure 3 is the second of the structural schematic diagrams of the cell voltage sampling and detection circuit provided by the embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] To make the objectives, technical solutions, and advantages of the present utility model clearer, the following will clearly and completely describe the technical solutions in the present utility model in conjunction with the drawings in the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the protection scope of the present utility model.

[0038] This embodiment relates to the field of battery management. With the increase in the cruising range of electric vehicles, the requirement for the energy density of the battery pack is getting higher and higher, and the role of the analog front-end chip becomes particularly prominent. The analog front-end chip is responsible for real-time collection of key signals such as cell voltage. Once there is an abnormal monitoring, the battery management system can quickly upload the fault to the whole vehicle to prompt the driver of driving safety.

[0039] In the battery cell voltage sampling process, multiple sampling channels are set according to the distribution of battery cells. If one or several sampling lines in the multiple sampling channels are damaged, the accuracy of the voltage sampling result will be affected. At the same time, since the analog front-end chip consumes some power of the battery cell during use, generally, the working power consumption of the analog front-end chip itself is relatively low, so the impact on the battery cell voltage is not significant. However, once the sampling channel is damaged, it will cause the power consumption of the analog front-end chip to increase. Relatively speaking, the analog front-end chip with a damaged channel will consume more power than a normal analog front-end chip. After a long time, the voltage of the battery cell supplying power to the analog front-end chip with a damaged channel will be lower than that of other battery cells, that is, the phenomenon of battery cell voltage stratification will occur, affecting the working stability of the battery cell.

[0040] Therefore, in the battery cell voltage sampling process, it is very important to detect and locate the damaged channel. However, there is currently no effective solution for detecting the damage of the sampling line and the position of the damaged channel.

[0041] In response to the above technical problems, the present embodiment provides an effective solution. The following will describe the detailed solutions of the battery cell voltage sampling detection circuit, battery management system, and electric vehicle provided by the present invention in combination with Figures 1 to 3 Describe the detailed solutions of the battery cell voltage sampling detection circuit, battery management system, and electric vehicle provided by the present invention.

[0042] Figure 1 It is one of the structural schematic diagrams of the battery cell voltage sampling detection circuit provided by the embodiment of the present invention.

[0043] As Figure 1 shown, the battery cell voltage sampling detection circuit provided by the embodiment of the present invention specifically includes: a voltage acquisition sub-circuit 10, a detection sub-circuit 20, and a processing sub-circuit 30.

[0044] The voltage acquisition sub-circuit 10 is respectively connected to each battery cell in the battery module. The input end of the detection sub-circuit 20 is respectively connected to the sampling lines between the voltage acquisition sub-circuit 10 and each battery cell, and the output end of the detection sub-circuit 20 is connected to the processing sub-circuit 30.

[0045] The voltage acquisition sub-circuit 10 is used to acquire the battery cell voltages on both sides of each battery cell;

[0046] The detection sub-circuit 20 is used to compare the battery cell voltages on the sampling lines on both sides of each battery cell, and after voltage isolation conversion, output the disconnection state signal corresponding to the sampling lines on both sides of each battery cell to the processing sub-circuit 30;

[0047] After receiving the disconnection state signal, the processing sub-circuit 30 obtains the on-off state of the sampling line of each battery cell according to the level state of the disconnection state signal.

[0048] It can be understood that the detection sub-circuit 20 can compare the cell voltages on the sampling lines on both the positive and negative sides of each cell, and after voltage isolation conversion, output a disconnection status signal corresponding to the corresponding cell. This disconnection status signal is essentially a level signal, and each group of comparison and isolation output links will output a corresponding disconnection status signal.

[0049] In practical applications, the number of output disconnection status signals is the same as the number of cells in the battery module. Subsequently, the processing sub-circuit 30 can directly determine the on-off status of the sampling lines of the corresponding cells according to the level status of each disconnection status signal, thereby accurately detecting the damage conditions and damaged channel positions of each sampling line in the cell voltage sampling link by using a simple circuit structure.

[0050] In this embodiment, the voltage acquisition sub-circuit 10 can be specifically implemented by cooperating an analog front-end chip with relevant peripheral circuits. Figure 2 An exemplary structural scheme for realizing the acquisition of cell voltages by cooperating an analog front-end chip with relevant peripheral circuits is shown.

[0051] See Figure 2 , the analog front-end chip P1 can adopt the MC337xC series chips. Taking the MC337xC series chips as an example, the pins Channel1 to Channel5 on the analog front-end chip P1 correspond to different voltage sampling channels. The AFE_VMODULE pin of the analog front-end chip P1 is connected to the positive electrode of the first cell V1 in the battery module, and the GNDH pin is connected to the negative electrode of the first cell V1. Furthermore, the voltage difference between the positive and negative electrodes of the battery module can be used to supply power to the analog front-end chip P1 to make the analog front-end chip P1 work normally and collect the cell voltages at both ends of different cells in the corresponding battery module. Figure 2 Four cells are exemplarily shown in , namely the first cell V1, the second cell V2, the third cell V3, and the fourth cell V4.

[0052] In the relevant peripheral circuits of the analog front-end chip, the capacitors C1, C11, C21, C31, and C41 are all ESD capacitors, which are used to prevent electrostatic damage to the circuit.

[0053] The resistors R1 and C2, R11 and C12, R21 and C22, R31 and C32, R41 and C42 form an RC filter circuit, which can filter out the common-mode interference in the circuit.

[0054] The resistors R2 and C3, R12 and C13, R22 and C23, R32 and C33, R42 and C43 form an RC filter circuit, which can filter out the differential-mode interference in the circuit.

[0055] It can be understood that by setting the above two RC filter circuits, the anti-interference ability of the voltage acquisition sub-circuit can be improved.

[0056] In one embodiment, referring to Figure 3 , the detection sub-circuit 20 specifically includes: a voltage comparison module 201 and an isolation output module 202.

[0057] The input terminals of the voltage comparison module 201 are respectively connected to the sampling lines between the voltage acquisition sub-circuit 10 and each battery cell, the output terminal of the voltage comparison module 201 is connected to the isolation output module 202, and the isolation output module 202 is also connected to the processing sub-circuit 30.

[0058] The voltage comparison module 201 is used to compare the battery cell voltages on the sampling lines on both sides of each battery cell, and output the comparison result signal corresponding to the sampling lines on both sides of each battery cell to the isolation output module 202.

[0059] The isolation output module 202 is used to perform voltage isolation conversion according to each comparison result signal, and output a disconnection state signal to the processing sub-circuit 30.

[0060] It can be understood that the comparison result signal is also a level signal. The comparison result signal depends on the number of battery cells and there are also multiple paths. After each path of comparison result signal is processed by the isolation output module, a corresponding disconnection state signal will be output.

[0061] In one embodiment, the voltage comparison module 202 includes multiple voltage division comparison units, and the set number of voltage division comparison units is the same as the number of battery cells.

[0062] The voltage division comparison unit includes: a first voltage division resistor, a second voltage division resistor, and a voltage comparator;

[0063] The first end of the first voltage resistor and the first end of the second voltage division resistor are respectively connected to the sampling lines on both sides of the voltage acquisition sub-circuit and the corresponding battery cell. The second end of the first voltage division resistor is connected to the non-inverting input terminal of the voltage comparator, the second end of the second voltage division resistor is connected to the inverting input terminal of the voltage comparator, and the output terminal of the voltage comparator is connected to the isolation output module.

[0064] Figure 3 Exemplarily shows a scenario where the number of battery cells in the battery module is 4, and there are four voltage division comparison units, namely the first voltage division comparison unit, the second voltage division comparison unit, the third voltage division comparison unit, and the fourth voltage division comparison unit.

[0065] Among them, the first voltage division and comparison unit includes a voltage division resistor RU11, a voltage division resistor RU13, and a voltage comparator U1. Among them, the first end of the voltage resistor RU11 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the negative electrode of the first battery cell V1, the first end of the voltage division resistor RU13 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the positive electrode of the first battery cell V1, the second end of the voltage division resistor RU11 is connected to the inverting input terminal U1- of the voltage comparator U1, the second end of the voltage division resistor RU13 is connected to the non-inverting input terminal U1+ of the voltage comparator U1, and the output terminal of the voltage comparator U1 is connected to the isolation output module 202. In addition, the inverting input terminal U1- of the voltage comparator U1 is also connected to the negative electrode of the battery module, that is, the high-voltage area ground terminal V-GNDH, through the voltage division resistor RU12, and the non-inverting input terminal U1+ of the voltage comparator U1 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU14 and RU15.

[0066] The second voltage division and comparison unit includes a voltage division resistor RU13, a voltage division resistor RU21, and a voltage comparator U2. Among them, the first end of the voltage resistor RU13 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the negative electrode of the second battery cell V2, the first end of the voltage division resistor RU21 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the positive electrode of the second battery cell V2, the second end of the voltage division resistor RU13 is connected to the inverting input terminal U2- of the voltage comparator U2, the second end of the voltage division resistor RU21 is connected to the non-inverting input terminal U2+ of the voltage comparator U2, and the output terminal of the voltage comparator U2 is connected to the isolation output module 202. In addition, the inverting input terminal U2- of the voltage comparator U1 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU14 and RU15, and the non-inverting input terminal U2+ of the voltage comparator U2 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU22 and RU23.

[0067] The third voltage division and comparison unit includes a voltage division resistor RU21, a voltage division resistor RU31, and a voltage comparator U3. Among them, the first end of the voltage resistor RU21 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the negative electrode of the third battery cell V3, the first end of the voltage division resistor RU31 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the positive electrode of the third battery cell V3, the second end of the voltage division resistor RU21 is connected to the inverting input terminal U3- of the voltage comparator U3, the second end of the voltage division resistor RU31 is connected to the non-inverting input terminal U3+ of the voltage comparator U3, and the output terminal of the voltage comparator U3 is connected to the isolation output module 202. In addition, the inverting input terminal U3- of the voltage comparator U3 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU22 and RU23, and the non-inverting input terminal U3+ of the voltage comparator U3 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU32 and RU33.

[0068] The fourth voltage division and comparison unit includes a voltage division resistor RU31, a voltage division resistor RU41, and a voltage comparator U4. Among them, the first end of the voltage resistor RU31 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the negative electrode of the fourth battery cell V4, the first end of the voltage division resistor RU41 is connected to the sampling line between the voltage acquisition sub-circuit 10 and the positive electrode of the fourth battery cell V4, the second end of the voltage division resistor RU31 is connected to the inverting input terminal U4- of the voltage comparator U4, the second end of the voltage division resistor RU41 is connected to the non-inverting input terminal U4+ of the voltage comparator U4, and the output terminal of the voltage comparator U4 is connected to the isolation output module 202. In addition, the inverting input terminal U4- of the voltage comparator U4 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU32 and RU33, and the non-inverting input terminal U4+ of the voltage comparator U4 is also connected to the high-voltage area ground terminal V-GNDH through the series-connected voltage division resistors RU42 and RU43.

[0069] In one embodiment, referring to Figure 3 , the voltage division and comparison unit further includes: a current-limiting resistor;

[0070] The current-limiting resistor is respectively connected to the output terminal of the voltage comparator and the isolation output module.

[0071] As Figure 3 shown in the four voltage division and comparison units, a current-limiting resistor RR1 is provided in the first voltage division and comparison unit, a current-limiting resistor RR2 is provided in the second voltage division and comparison unit, a current-limiting resistor RR3 is provided in the third voltage division and comparison unit, and a current-limiting resistor RR4 is provided in the fourth voltage division and comparison unit.

[0072] In one embodiment, the voltage division and comparison unit further includes: an anti-reverse diode;

[0073] The positive electrode of the anti-reverse diode is connected to the output terminal of the voltage comparator, and the negative electrode of the anti-reverse diode is connected to the isolation output module. The anti-reverse diode is used to prevent the current in the line from flowing in the reverse direction.

[0074] As Figure 3 In the four-component voltage division comparison unit shown, an anti-reverse diode D1 is provided in the first voltage division comparison unit, an anti-reverse diode D2 is provided in the second voltage division comparison unit, an anti-reverse diode D3 is provided in the third voltage division comparison unit, and an anti-reverse diode D4 is provided in the fourth voltage division comparison unit.

[0075] It can be understood that the setting of the anti-reverse diode and the current-limiting resistor can improve the working safety and stability of each voltage division comparison unit.

[0076] In one embodiment, the isolation output module includes a plurality of optocoupler isolation units, and the number of optocoupler isolation units provided is the same as the number of battery cells;

[0077] The optocoupler isolation unit includes: an optocoupler switch and a triode;

[0078] The base of the triode is connected to the output terminal of the voltage comparison module, the collector of the triode is connected to the optocoupler switch, the emitter of the triode is connected to the high-voltage area ground terminal, and the optocoupler switch is also connected to the processing sub-circuit.

[0079] In this embodiment, the optocoupler switch is used to isolate the high-voltage area from the low-voltage area to ensure the working safety of the entire circuit, and the triode is used to control the open-circuit state signal.

[0080] Figure 3 An exemplary scenario with four groups of optocoupler isolation units is shown, namely the first optocoupler isolation unit, the second optocoupler isolation unit, the third optocoupler isolation unit, and the fourth optocoupler isolation unit.

[0081] Among them, the first optocoupler isolation unit includes an optocoupler switch G1 and a triode N1. The base of the triode N1 is connected to the output terminal of the voltage comparison module 201, the collector of the triode N1 is connected to the optocoupler switch G1, the emitter of the triode N1 is connected to the high-voltage area ground terminal V-GNDH, and the optocoupler switch G1 is also connected to the processing sub-circuit 30.

[0082] The second optocoupler isolation unit includes an optocoupler switch G2 and a triode N2. The base of the triode N2 is connected to the output terminal of the voltage comparison module 201, the collector of the triode N2 is connected to the optocoupler switch G2, the emitter of the triode N2 is connected to the high-voltage area ground terminal V-GNDH, and the optocoupler switch G2 is also connected to the processing sub-circuit 30.

[0083] The third opto-isolation unit includes an opto-switch G3 and a triode N3. The base of the triode N3 is connected to the output terminal of the voltage comparison module 201. The collector of the triode N3 is connected to the opto-switch G3. The emitter of the triode N3 is connected to the high-voltage area ground terminal V-GNDH. The opto-switch G3 is also connected to the processing sub-circuit 30.

[0084] The fourth opto-isolation unit includes an opto-switch G4 and a triode N4. The base of the triode N4 is connected to the output terminal of the voltage comparison module 201. The collector of the triode N4 is connected to the opto-switch G4. The emitter of the triode N4 is connected to the high-voltage area ground terminal V-GNDH. The opto-switch G4 is also connected to the processing sub-circuit 30.

[0085] In one embodiment, the opto-isolation unit further includes: a third voltage-dividing resistor, a fourth voltage-dividing resistor, a fifth voltage-dividing resistor, and a sixth voltage-dividing resistor;

[0086] The first end of the third voltage-dividing resistor is connected to the high-voltage area power supply. The first end of the fourth voltage-dividing resistor is connected to the low-voltage area power supply. The first end of the fifth voltage-dividing resistor is connected to the low-voltage area ground terminal. The second ends of the third voltage-dividing resistor, the fourth voltage-dividing resistor, and the fifth voltage-dividing resistor are all connected to the opto-switch. The sixth voltage-dividing resistor is respectively connected to the emitter of the triode and the high-voltage area ground terminal.

[0087] As Figure 3 shown, the first opto-isolation unit includes: a voltage-dividing resistor RU16, a voltage-dividing resistor RU17, a voltage-dividing resistor RU18, and a voltage-dividing resistor RU19;

[0088] The first end of the voltage-dividing resistor RU16 is connected to the high-voltage area power supply VDD 5V. The first end of the voltage-dividing resistor RU17 is connected to the low-voltage area power supply VCC 5V. The first end of the voltage-dividing resistor RU19 is connected to the low-voltage area ground terminal GNDH. The second ends of the voltage-dividing resistor RU16, the voltage-dividing resistor RU17, and the voltage-dividing resistor RU19 are all connected to the opto-switch G1. The voltage-dividing resistor RU18 is respectively connected to the emitter of the triode N1 and the high-voltage area ground terminal V-GNDH.

[0089] The second opto-isolation unit includes: a voltage-dividing resistor RU24, a voltage-dividing resistor RU25, a voltage-dividing resistor RU26, and a voltage-dividing resistor RU27;

[0090] The first terminal of the voltage-dividing resistor RU24 is connected to the high-voltage area power supply VDD 5V, the first terminal of the voltage-dividing resistor RU25 is connected to the low-voltage area power supply VCC 5V, the first terminal of the voltage-dividing resistor RU27 is connected to the low-voltage area ground terminal GNDH, the second terminals of the voltage-dividing resistor RU24, the voltage-dividing resistor RU25, and the voltage-dividing resistor RU27 are all connected to the optocoupler switch G2, and the voltage-dividing resistor RU26 is respectively connected to the emitter of the triode N2 and the high-voltage area ground terminal V-GNDH.

[0091] The third optocoupler isolation unit includes: a voltage-dividing resistor RU34, a voltage-dividing resistor RU35, a voltage-dividing resistor RU36, and a voltage-dividing resistor RU37;

[0092] The first terminal of the voltage-dividing resistor RU34 is connected to the high-voltage area power supply VDD 5V, the first terminal of the voltage-dividing resistor RU35 is connected to the low-voltage area power supply VCC 5V, the first terminal of the voltage-dividing resistor RU37 is connected to the low-voltage area ground terminal GNDH, the second terminals of the voltage-dividing resistor RU34, the voltage-dividing resistor RU35, and the voltage-dividing resistor RU37 are all connected to the optocoupler switch G3, and the voltage-dividing resistor RU36 is respectively connected to the emitter of the triode N3 and the high-voltage area ground terminal V-GNDH.

[0093] The fourth optocoupler isolation unit includes: a voltage-dividing resistor RU44, a voltage-dividing resistor RU45, a voltage-dividing resistor RU46, and a voltage-dividing resistor RU47;

[0094] The first terminal of the voltage-dividing resistor RU44 is connected to the high-voltage area power supply VDD 5V, the first terminal of the voltage-dividing resistor RU45 is connected to the low-voltage area power supply VCC 5V, the first terminal of the voltage-dividing resistor RU47 is connected to the low-voltage area ground terminal GNDH, the second terminals of the voltage-dividing resistor RU44, the voltage-dividing resistor RU45, and the voltage-dividing resistor RU47 are all connected to the optocoupler switch G4, and the voltage-dividing resistor RU46 is respectively connected to the emitter of the triode N4 and the high-voltage area ground terminal V-GNDH.

[0095] In one embodiment, referring to Figure 3 , the processing sub-circuit 30 includes: a processing chip P2 and a power management chip P3;

[0096] The processing chip P2 is respectively connected to the output terminal of the detection sub-circuit and the wake-up pin of the power management chip P3;

[0097] After receiving the disconnection state signal, the processing chip P2 obtains the on / off state of the sampling line of each battery cell according to the level state of the disconnection state signal, and outputs a wake-up signal to the power management chip P3 when detecting that the level state of the disconnection state signal is the target state.

[0098] Figure 3In the shown scenario, the processing chip P2 receives the output signals of four groups of optocoupler isolation units in the isolation output module 202 in the detection sub-circuit through four receiving pins GPIO1, GPIO2, GPIO3, and GPIO4, and the output signals of the four groups of optocoupler isolation units will be transmitted to four wake-up pins Wake1, Wake2, Wake3, and Wake4 of the power management chip P3.

[0099] In practical applications, the processing chip P2 can adopt an MCU (Micro Controller Unit), and the power management chip P3 can adopt an SBC (System Base Chip).

[0100] The following combines Figure 3 to illustrate the working principle of the cell voltage sampling and detection circuit provided in this embodiment:

[0101] Taking Figure 3 the working process of a certain sampling and detection branch of the cell voltage as an example, specifically taking the detection process of the on-off state of the sampling lines on both sides of the first cell V1 as an example for illustration.

[0102] When there is no sampling line disconnection fault on both sides of the first cell V1, the receiving pin GPIO1 of the processing chip P2 is a low-level signal.

[0103] When there is a sampling line disconnection fault on both sides of the first cell V1, at this time, the resistance value of the voltage-dividing resistor corresponding to the first cell V1 satisfies RU14 + RU15 > RU12. After voltage division, the input voltage of the voltage comparator U1 satisfies U1- < U1+. The output end of the voltage comparator U1 outputs a comparison result signal in a high-level state. The triode N1 is an NPN triode. When the base of the triode N1 is at a high level, it satisfies the conduction state. At this time, the collector and emitter of the triode N1 output through the pull-up VDD 5V, the diode in the optocoupler switch G1 conducts, so the 3 contact and 4 contact of the optocoupler switch G1 are attracted, and the output end is conducted. The GPIO1 pin of the processing chip P2 collects a disconnection state signal in a high-level state, and it can be judged that the Channel2 channel of the analog front-end chip P1 is in a sampling line disconnection state at this time.

[0104] When the battery management system is in the sleep state, the power management chip P3 is also in the sleep state. At this time, the disconnection state signal received by the GPIO1 pin can be further input to the wake-up pin Wake1 of the power management chip, thereby waking up the power management chip P3. At this time, the power management chip P3 can detect the abnormal situation of the cell voltage acquisition in time and inform the user to handle it in time to avoid greater losses.

[0105] As can be seen, the cell voltage sampling and detection circuit provided by the present utility model has at least the following advantages:

[0106] First, when a break fault occurs in the sampling line during the cell voltage sampling process, the sampling channel with the break fault can be detected in a timely manner, and the detection process is more accurate and reliable.

[0107] Second, when the battery management system is in the sleep state, the power management chip can be awakened to wake up the battery management system, so as to report the fault in a timely manner.

[0108] Third, the voltage loss at the power input end is reduced, so that the minimum operating voltage of the battery management system is lower, and the minimum operating voltage of the power management chip is increased, enabling a wider range of choices, and lower-cost devices can be selected, thus saving costs.

[0109] In addition, the embodiment of the present utility model further provides a battery management system, which includes the cell voltage sampling and detection circuit provided by each of the above embodiments.

[0110] Furthermore, the embodiment of the present utility model further provides an electric vehicle, which includes the cell voltage sampling and detection circuit provided by each of the above embodiments or the above battery management system.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, rather than to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present utility model.

Claims

1. A cell voltage sampling and detection circuit, characterized in that: include: A voltage acquisition subcircuit, a detection subcircuit, and a processing subcircuit; The voltage collection subcircuit is respectively connected to each battery cell in the battery module, the input end of the detection subcircuit is respectively connected to the sampling line between the voltage collection subcircuit and each battery cell, and the output end of the detection subcircuit is connected to the processing subcircuit; The voltage collection subcircuit is used to collect the cell voltage of each cell; The detection subcircuit is used to compare the cell voltages on the sampling lines on both sides of each cell, and after voltage isolation conversion, output the disconnection status signal corresponding to the sampling lines on both sides of each cell to the processing subcircuit; After receiving the disconnection status signal, the processing subcircuit obtains the on / off status of the sampling line of each battery cell according to the level state of the disconnection status signal.

2. The cell voltage sampling and detection circuit according to claim 1, characterized in that: The detection subcircuit includes: a voltage comparison module and an isolation output module; The input end of the voltage comparison module is respectively connected to the sampling line between the voltage acquisition subcircuit and each battery cell, the output end of the voltage comparison module is connected to the isolation output module, and the isolation output module is also connected to the processing subcircuit; The voltage comparison module is used to compare the cell voltages on the sampling lines on both sides of each cell, and output the comparison result signals corresponding to the sampling lines on both sides of each cell to the isolation output module; The isolation output module is used to output a disconnection status signal to the processing sub-circuit after performing voltage isolation conversion according to each of the comparison result signals.

3. The cell voltage sampling and detection circuit according to claim 2, characterized in that: The voltage comparison module includes a plurality of voltage division comparison units, and the number of the voltage division comparison units is consistent with the number of the battery cells; The voltage division comparison unit includes: a first voltage division resistor, a second voltage division resistor and a voltage comparator; The first end of the first voltage resistor and the first end of the second voltage-dividing resistor are respectively connected to the voltage acquisition sub-circuit and the sampling lines on both sides of the corresponding battery cell, the second end of the first voltage-dividing resistor is connected to the non-inverting input end of the voltage comparator, the second end of the second voltage-dividing resistor is connected to the inverting input end of the voltage comparator, and the output end of the voltage comparator is connected to the isolation output module.

4. The cell voltage sampling and detection circuit according to claim 3, characterized in that: The voltage division comparison unit further includes: a current limiting resistor; The current limiting resistor is connected to the output end of the voltage comparator and the isolation output module respectively.

5. The cell voltage sampling and detection circuit according to claim 3 or 4, characterized in that: The voltage division comparison unit further includes: an anti-reverse diode; The anode of the anti-reverse diode is connected to the output end of the voltage comparator, and the cathode of the anti-reverse diode is connected to the isolation output module.

6. The cell voltage sampling and detection circuit according to claim 2, characterized in that: The isolated output module includes a plurality of optical coupling isolation units, and the number of the optical coupling isolation units is consistent with the number of the battery cells; The optical coupling isolation unit includes: an optical coupling switch and a triode; The base of the transistor is connected to the output end of the voltage comparison module, the collector of the transistor is connected to the optocoupler switch, the emitter of the transistor is connected to the ground end of the high voltage area, and the optocoupler switch is also connected to the processing sub-circuit.

7. The cell voltage sampling and detection circuit according to claim 6, characterized in that: The optical coupling isolation unit further includes: a third voltage-dividing resistor, a fourth voltage-dividing resistor, a fifth voltage-dividing resistor and a sixth voltage-dividing resistor; The first end of the third voltage-dividing resistor is connected to the high-voltage area power supply, the first end of the fourth voltage-dividing resistor is connected to the low-voltage area power supply, the first end of the fifth voltage-dividing resistor is connected to the low-voltage area ground terminal, the second end of the third voltage-dividing resistor, the second end of the fourth voltage-dividing resistor and the second end of the fifth voltage-dividing resistor are all connected to the optocoupler switch, and the sixth voltage-dividing resistor is respectively connected to the emitter of the transistor and the high-voltage area ground terminal.

8. The cell voltage sampling and detection circuit according to claim 1, characterized in that: The processing subcircuit includes: a processing chip and a power management chip; The processing chip is respectively connected to the output end of the detection sub-circuit and the wake-up pin of the power management chip; After receiving the disconnection status signal, the processing chip obtains the on-off state of the sampling line of each battery cell according to the level state of the disconnection status signal, and outputs a wake-up signal to the power management chip when detecting that the level state of the disconnection status signal is the target state.

9. A battery management system, characterized in that: It comprises a cell voltage sampling and detection circuit as described in any one of claims 1 to 8.

10. An electric vehicle, characterized in that: It comprises the cell voltage sampling and detection circuit as described in any one of claims 1 to 8 or the battery management system as described in claim 9.

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