Battery voltage detection circuit and fault diagnosis method

Abstract

The invention provides a battery voltage detection circuit and a fault diagnosis method, the battery voltage detection circuit comprises N multiplexers and N voltage measurement units, each multiplexer outputs an accessed first voltage signal or a second voltage signal according to a received control signal, and the N voltage measurement units are connected with the N multiplexers. And the first voltage signal and the second voltage signal accessed by the same multiplexer respectively correspond to different batteries. Therefore, each multiplexer is controlled to receive different control signals, so that the voltage measurement unit corresponding to the multiplexer can measure the first voltage signal and the second voltage signal corresponding to different batteries, and multiplexing of the N voltage measurement units is realized. Therefore, only N voltage measuring units are needed to detect the voltage of N batteries connected in series, so that the circuit area can be reduced and the cost can be saved.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuits, and in particular to a battery voltage detection circuit and a fault diagnosis method. Background Art

[0002] The Analog Front End (AFE) chip in the Battery Management System (BMS) needs to accurately measure the voltage of multiple batteries, and, for functional safety, it is necessary to diagnose the failure of the measurement circuit. However, the existing battery voltage detection circuit is complex and redundant, resulting in a large circuit area and high cost. Summary of the invention

[0003] The present invention provides a battery voltage detection circuit and a fault diagnosis method to reduce the circuit and save costs.

[0004] According to a first aspect of the technical solution of the present invention, there is provided a battery voltage detection circuit, comprising:

[0005] A first voltage conversion module, the first voltage conversion module is used to convert the voltages at both ends of N batteries into N first voltage signals for output, wherein the voltage value of the first voltage signal is smaller than the voltage at both ends of the corresponding battery;

[0006] A second voltage conversion module, the second voltage conversion module is used to convert the voltages at both ends of the N batteries into N second voltage signals for output, wherein the voltage value of the second voltage signal is smaller than the voltage at both ends of the corresponding battery;

[0007] N multiplexers, the multiplexers are used to output the first voltage signal or the second voltage signal connected to the multiplexer according to the control signal received by the multiplexer, the multiplexer includes a selector control end, a first selector input end, a second selector input end and a selector output end, the selector control end is used to connect the control signal, the first selector input end is used to connect one of the first voltage signals, the second selector input end is used to connect one of the second voltage signals, in the same multiplexer, the connected first voltage signal and the second voltage signal correspond to different batteries respectively, and the selector output end is used to output the connected first voltage signal or the second voltage signal as the output end voltage;

[0008] N voltage measuring units, the N voltage measuring units correspond one-to-one to the N multiplexers, and each voltage measuring unit is used to measure the output terminal voltage of the corresponding multiplexer.

[0009] Optionally, the first voltage conversion module includes N first voltage conversion units, the N first voltage conversion units correspond to the N batteries one by one, each of the first voltage conversion units is used to convert the voltage at both ends of a battery into a first voltage signal output, the first voltage conversion unit has a first voltage input terminal, a second voltage input terminal and a first voltage signal output terminal, the first voltage input terminal is coupled to the positive electrode of the corresponding battery, and the second voltage input terminal is coupled to the negative electrode of the corresponding battery;

[0010] The second voltage conversion module includes N second voltage conversion units, and the N second voltage conversion units correspond one-to-one to the N batteries. Each second voltage conversion unit is used to convert the voltage across a battery into a second voltage signal output. The second voltage conversion unit has a third voltage input terminal, a fourth voltage input terminal and a second voltage signal output terminal. The third voltage input terminal is coupled to the positive pole of the corresponding battery, and the fourth voltage input terminal is coupled to the negative pole of the corresponding battery.

[0011] Optionally, also include:

[0012] (N+1) first resistors, the first end of the (N+1) first resistors is connected to the positive electrodes of the N batteries and the negative electrode of the Nth battery, the second end of the (N+1) first resistors is connected to the first voltage input ends or the second voltage input ends of the N first voltage conversion units, the first voltage input end of the first first voltage conversion unit is connected to the second end of the first first resistor, the second voltage input end of the i-th first voltage conversion unit and the first voltage input end of the (i+1)-th first voltage conversion unit are commonly connected to the second end of the (i+1)-th first resistor, the second voltage input end of the N-th first voltage conversion unit is connected to the second end of the (N+1)-th first resistor, i is a positive integer, and 1≤i≤N-1;

[0013] (N+1) second resistors, the first end of the (N+1) second resistors is connected to the positive electrodes of the N batteries and the negative electrode of the Nth battery, the second end of the (N+1) second resistors is connected to the third voltage input end or the fourth voltage input end of the N second voltage conversion units, the third voltage input end of the first second voltage conversion unit is connected to the second end of the first second resistor, the fourth voltage input end of the i-th second voltage conversion unit and the third voltage input end of the (i+1)-th second voltage conversion unit are commonly connected to the second end of the (i+1)-th second resistor, and the fourth voltage input end of the N-th second voltage conversion unit is connected to the second end of the (N+1)-th second resistor;

[0014] N first capacitors, the N first capacitors correspond one-to-one to the N first voltage conversion units, and two ends of the first capacitors are respectively connected to the corresponding first voltage input terminal and second voltage input terminal;

[0015] N second capacitors, the N second capacitors correspond one-to-one to the N second voltage conversion units, and two ends of the second capacitors are respectively connected to the corresponding third voltage input terminal and fourth voltage input terminal.

[0016] Optionally, the voltage measuring unit includes an analog-to-digital converter.

[0017] According to a second aspect of the technical solution of the present invention, a fault diagnosis method is provided, comprising:

[0018] Convert the voltages at both ends of the N batteries into N first voltage signal outputs;

[0019] Convert the voltages at both ends of the N batteries into N second voltage signal outputs;

[0020] Performing N sampling cycles to measure the first voltage signal and the second voltage signal corresponding to each battery in the N batteries, the method for performing any one of the N sampling cycles comprising: inputting corresponding control signals to two associated multiplexers respectively, wherein the first voltage signal connected to one of the two associated multiplexers and the second voltage signal connected to the other of the two associated multiplexers correspond to the same battery; the two associated multiplexers respectively output the first voltage signal and the second voltage signal corresponding to the same battery according to the control signals received respectively; the voltage measurement units corresponding to the two associated multiplexers respectively measure the first voltage signal and the second voltage signal;

[0021] The fault location in the battery voltage detection circuit is determined according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries.

[0022] Optionally, judging a fault location in the battery voltage detection circuit according to a measured first voltage signal and a second voltage signal corresponding to each battery in the N batteries includes:

[0023] If the first voltage signal and the second voltage signal measured within a sampling period are equal, it is determined that the first voltage conversion unit outputting the first voltage signal, the second voltage conversion unit outputting the second voltage signal, and the two voltage measurement units detecting the first voltage signal and the second voltage signal are all normal.

[0024] Optionally, judging a fault location in the battery voltage detection circuit according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries further includes:

[0025] If, in two associated multiplexers, a first voltage signal connected to the first selector input terminal of one and a second voltage signal connected to the second selector input terminal of the other correspond to the same battery, and the second voltage signal connected to the second selector input terminal of the one and the first voltage signal connected to the first selector input terminal of the other correspond to the same battery, then the two voltage detection units corresponding to the two multiplexers respectively detect the voltages of the corresponding two batteries within two sampling periods;

[0026] If the first voltage signal and the second voltage signal measured in one sampling period are the same, and the first voltage signal and the second voltage signal measured in another sampling period are different, it is determined that one or both of the first voltage conversion unit and the second voltage conversion unit used in the another sampling period are faulty;

[0027] If the first voltage signal and the second voltage signal measured in the two sampling periods are different, it is determined that one or both of the two voltage measurement units corresponding to the two multiplexers are faulty.

[0028] Optionally, judging a fault location in the battery voltage detection circuit according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries further includes:

[0029] If, among the three associated multiplexers, one multiplexer receives a first voltage signal and a second voltage signal corresponding to different batteries, and the other two multiplexers receive first voltage signals and second voltage signals corresponding to different batteries respectively, the second voltage signal received by one of the other multiplexers corresponds to the same battery as the first voltage signal received by the one multiplexer, and the first voltage signal received by another of the other multiplexers corresponds to the same battery as the second voltage signal received by the one multiplexer, then when in one sampling period, the two voltage measurement results corresponding to the two multiplexers whose output terminal voltages correspond to the same battery are the same, and in another sampling period, the two voltage measurement results corresponding to the two multiplexers whose output terminal voltages correspond to the same battery are different, it is judged that the fault location lies in one, two or three of the voltage measurement units corresponding to the first voltage conversion unit, the second voltage conversion unit and one of the other two multiplexers used in the other sampling period.

[0030] According to a third aspect of the technical solution of the present invention, there is provided an electronic device, comprising the above-mentioned battery voltage detection circuit.

[0031] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0032] In the battery voltage detection circuit provided by the technical solution of the present invention, N multiplexers and N voltage measurement units are included, each multiplexer outputs the first voltage signal or the second voltage signal connected according to the received control signal, and the first voltage signal and the second voltage signal connected by the same multiplexer correspond to different batteries respectively. Therefore, by controlling each multiplexer to receive different control signals, the voltage measurement unit corresponding to the multiplexer can measure the first voltage signal and the second voltage signal corresponding to different batteries, and the multiplexing of the N voltage measurement units is realized, so that only N voltage measurement units are needed to detect the voltages of the N batteries connected in series, thereby reducing the circuit area and saving costs.

[0033] In the fault diagnosis method provided by the technical solution of the present invention, by performing N sampling cycles, the first voltage signal and the second voltage signal corresponding to each battery in the N batteries can be measured, and the specific location of the fault in the circuit can be determined through the measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a battery voltage detection circuit;

[0035] Figure 2 The circuit structure of a battery voltage detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 1 ;

[0036] Figure 3 The circuit structure of a battery voltage detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 2 . DETAILED DESCRIPTION

[0037] As described in the background art, the existing battery voltage detection circuit is complex and redundant, resulting in a large circuit area and high cost. A detailed description is given below. In a battery voltage detection circuit, each battery corresponds to a detection channel and a balance detection channel.

[0038] Figure 1 This is a schematic diagram of the circuit structure of a battery voltage detection circuit. For ease of understanding, Figure 1 The figure schematically shows the m-1th battery, the mth battery, the m+1th battery in a group of series-connected batteries, and two corresponding detection channels when detecting the voltage Vn of the mth battery, where m is a positive integer greater than 1.

[0039] Please refer to Figure 1 When detecting the mth battery voltage Vm, a corresponding detection channel and a balanced detection channel are required, the detection channel includes a first voltage conversion unit and a first analog-to-digital converter, and the balanced detection channel includes a second conversion unit and a second analog-to-digital converter.

[0040] The first voltage conversion unit and the second voltage conversion unit are used to convert the m-th battery voltage Vm into a first voltage signal and a second voltage signal for output respectively, and the first analog-to-digital converter and the second analog-to-digital converter are used to measure the received first voltage signal and the second voltage signal respectively. If the measurement results of the first analog-to-digital converter and the second analog-to-digital converter are consistent, it can be determined that the battery voltage detection circuit is normal. If the measurement results of the first analog-to-digital converter and the second analog-to-digital converter are inconsistent, it can be determined that there is a fault in the battery voltage detection circuit, but the specific fault location cannot be determined.

[0041] Therefore, if N batteries connected in series are measured, 2N analog-to-digital converters are required, resulting in a larger circuit area and higher cost.

[0042] In view of this, the technical solution of the present invention creatively proposes a battery voltage detection circuit, including: a first voltage conversion module, the first voltage conversion module is used to convert the voltages at both ends of N batteries into N first voltage signal outputs, the voltage value of the first voltage signal is less than the voltages at both ends of the corresponding batteries; a second voltage conversion module, the second voltage conversion module is used to convert the voltages at both ends of N batteries into N second voltage signal outputs, the voltage value of the second voltage signal is less than the voltages at both ends of the corresponding batteries; N multiplexers, the multiplexers are used to output the first voltage signal or the second voltage signal connected to the multiplexers according to the control signal received by the multiplexers, the The multiplexer includes a selector control end, a first selector input end, a second selector input end and a selector output end, wherein the selector control end is used to access a control signal, the first selector input end is used to access a first voltage signal, the second selector input end is used to access a second voltage signal, in the same multiplexer, the accessed first voltage signal and the second voltage signal correspond to different batteries respectively, and the selector output end is used to output the accessed first voltage signal or the second voltage signal as an output end voltage; N voltage measuring units, the N voltage measuring units correspond one-to-one to the N multiplexers, and each voltage measuring unit is used to measure the output end voltage of the corresponding multiplexer.

[0043] By controlling each multiplexer to receive different control signals, the voltage measuring unit corresponding to the multiplexer can measure the first voltage signal and the second voltage signal corresponding to different batteries, thereby realizing the multiplexing of N voltage measuring units, and further making it necessary to detect the voltages of N batteries connected in series with only N voltage measuring units, thereby reducing the circuit area and saving costs.

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the embodiments in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] Figure 2 The circuit structure of a battery voltage detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 1 .

[0046] Please refer to Figure 2 The battery voltage detection circuit includes a first voltage conversion module VC, a second voltage conversion module CB, N multiplexers and N voltage measurement units, where N is a positive integer greater than 1.

[0047] The first voltage conversion module VC is used to convert the voltages at both ends of N batteries into N first voltage signals for output, wherein the voltage value of the first voltage signal is smaller than the voltage at both ends of the corresponding battery.

[0048] In this embodiment, the first voltage conversion module VC includes N first voltage conversion units, the N first voltage conversion units correspond to N batteries one by one, each first voltage conversion unit is used to convert the voltage at both ends of a battery into a first voltage signal output, the first voltage conversion unit has a first voltage input terminal, a second voltage input terminal and a first voltage signal output terminal, the first voltage input terminal is coupled to the positive electrode of the corresponding battery, and the second voltage input terminal is coupled to the negative electrode of the corresponding battery. Therefore, the N battery voltages are output as N first voltage signals one by one through the N first voltage conversion units.

[0049] The second voltage conversion module CB is used to convert the voltages at both ends of the N batteries into N second voltage signals for output, wherein the voltage value of the second voltage signal is smaller than the voltage at both ends of the corresponding battery.

[0050] In this embodiment, the second voltage conversion module CB includes N second voltage conversion units, the N second voltage conversion units correspond to N batteries one by one, each second voltage conversion unit is used to convert the voltage at both ends of a battery into a second voltage signal output, the second voltage conversion unit has a third voltage input terminal, a fourth voltage input terminal and a second voltage signal output terminal, the third voltage input terminal is coupled to the positive electrode of the corresponding battery, and the fourth voltage input terminal is coupled to the negative electrode of the corresponding battery. Therefore, the N battery voltages are output as N second voltage signals through the N second voltage conversion units one by one.

[0051] In this embodiment, the first voltage conversion unit and the second voltage conversion unit are both used to convert the input higher battery voltage into lower first voltage signals and second voltage signals and output them to the corresponding voltage measurement units, so that the voltage magnitudes of the first voltage signal and the second voltage signal are within the measurement range of the voltage measurement unit, and the first voltage conversion unit is the same as the second voltage conversion unit, ensuring that the voltage conversion processing of the battery voltage input to the first voltage conversion unit and the second voltage conversion unit is the same.

[0052] In this embodiment, N=2 is used as an example to describe that if the voltages at both ends of two batteries are to be detected, the corresponding battery voltage detection circuit includes two first voltage conversion units, two second voltage conversion units, two multiplexers and two voltage measurement units.

[0053] In the analog front-end chip, the first voltage conversion unit is used as a battery voltage acquisition channel for the battery corresponding to it, and the second voltage conversion unit is used as a battery balancing channel for the battery corresponding to it. Since the battery balancing channel can obtain the voltage of the battery corresponding to it, the second voltage conversion unit can be reused in fault diagnosis and used as a detection channel in fault diagnosis.

[0054] In this embodiment, the battery voltage detection circuit further includes (N+1) first resistors R1, (N+1) second resistors R2, N first capacitors C1, and N second capacitors C2.

[0055] The first end of the (N+1)th first resistor R1 is connected to the positive electrodes of the N batteries and the negative electrode of the Nth battery, the second end of the (N+1)th first resistor R1 is connected to the first voltage input end or the second voltage input end of the N first voltage conversion units, the first voltage input end of the first first voltage conversion unit is connected to the second end of the first first resistor R1, the second voltage input end of the i-th first voltage conversion unit and the first voltage input end of the (i+1)-th first voltage conversion unit are commonly connected to the second end of the (i+1)-th first resistor R1, the second voltage input end of the N-th first voltage conversion unit is connected to the second end of the (N+1)-th first resistor R1, i is a positive integer, and 1≤i≤N-1; the first end of the (N+1)th second resistor R2 is connected to the positive electrodes of the N batteries and the negative electrode of the Nth battery, the (N+1)th second resistor R2 The second end is connected to the third voltage input end or the fourth voltage input end of the N second voltage conversion units, the third voltage input end of the first second voltage conversion unit is connected to the second end of the first second resistor R2, the fourth voltage input end of the i-th second voltage conversion unit and the third voltage input end of the (i+1)-th second voltage conversion unit are commonly connected to the second end of the (i+1)-th second resistor R2, and the fourth voltage input end of the N-th second voltage conversion unit is connected to the second end of the (N+1)-th second resistor R2; the N first capacitors C1 correspond one-to-one to the N first voltage conversion units, and the two ends of the first capacitor C1 are respectively connected to the corresponding first voltage input end and the second voltage input end; the N second capacitors C2 correspond one-to-one to the N second voltage conversion units, and the two ends of the second capacitor C2 are respectively connected to the corresponding third voltage input end and the fourth voltage input end. Specifically, two first resistors R1 and a first capacitor C1 connected to a first voltage conversion unit can constitute a filtering unit, which performs filtering processing on the corresponding battery voltage before entering the corresponding first voltage conversion unit, thereby improving the quality of the voltage entering the first voltage conversion unit. Similarly, two second resistors R2 and a second capacitor C2 connected to a second voltage conversion unit can constitute a filtering unit, which performs filtering processing on the corresponding battery voltage before entering the corresponding second voltage conversion unit, thereby improving the quality of the voltage entering the second voltage conversion unit.

[0056] In this embodiment, each battery voltage is filtered, and the first voltage conversion unit is identical to the second voltage conversion unit, so that the first voltage signal and the second voltage signal corresponding to the same battery voltage are identical when the first voltage conversion unit and the second voltage conversion unit are not faulty.

[0057] The multiplexer is used to output the first voltage signal or the second voltage signal connected to the multiplexer according to the control signal received by the multiplexer. The multiplexer includes a selector control end, a first selector input end, a second selector input end and a selector output end. The selector control end is used to connect the control signal, the first selector input end is used to connect a first voltage signal, and the second selector input end is used to connect a second voltage signal. In the same multiplexer, the connected first voltage signal and the second voltage signal correspond to different batteries respectively, and the selector output end is used to output the connected first voltage signal or the second voltage signal as the output end voltage.

[0058] The N voltage measurement units correspond to the N multiplexers one by one, and each voltage measurement unit is used to measure the output terminal voltage of the corresponding multiplexer.

[0059] In this embodiment, the voltage measuring unit may include an analog-to-digital converter.

[0060] The voltage values ​​of the first voltage signal and the second voltage signal are within the measurement range of the voltage measurement unit. Therefore, the first voltage conversion unit and the second conversion unit are used to convert the higher voltage of the higher N series-connected batteries connected to the first voltage input terminal, the second voltage input terminal, the third voltage input terminal, and the fourth voltage input terminal into the first voltage signal and the second voltage signal whose voltage value is within the voltage range that the voltage measurement unit can detect.

[0061] Therefore, the multiplexer can output the first voltage signal or the second voltage signal corresponding to different batteries according to the control signal, so that the multiplexer can measure the first voltage signal and the second voltage signal corresponding to different batteries respectively in two sampling cycles, thereby realizing the multiplexing of the voltage measurement unit, reducing the number of voltage detection units in the circuit, thereby reducing the circuit area and saving costs.

[0062] In summary, in the battery voltage detection circuit provided by the present invention, N multiplexers and N voltage measurement units are included, each multiplexer outputs the first voltage signal or the second voltage signal connected according to the received control signal, and the first voltage signal and the second voltage signal connected by the same multiplexer correspond to different batteries respectively. Therefore, by controlling each multiplexer to receive different control signals, the voltage measurement unit corresponding to the multiplexer can measure the first voltage signal and the second voltage signal corresponding to different batteries, and the multiplexing of N voltage measurement units is realized, so that only N voltage measurement units are needed to detect the voltages of N batteries connected in series, thereby reducing the circuit area and saving costs.

[0063] The embodiment of the present invention further provides a fault diagnosis method, which uses the battery voltage detection circuit mentioned above. The fault diagnosis method includes:

[0064] The voltages at both ends of the N batteries are converted into N first voltage signals for output.

[0065] The voltages across the N batteries are converted into N second voltage signals for output.

[0066] It should be noted that converting the voltages across the N batteries into N first voltage signal outputs respectively and converting the voltages across the N batteries into N second voltage signal outputs respectively are two parallel steps.

[0067] N sampling cycles are performed to measure the first voltage signal and the second voltage signal corresponding to each battery in the N batteries. The method for performing any sampling cycle in the N sampling cycles includes: inputting corresponding control signals to two associated multiplexers respectively, and in the two associated multiplexers, the first voltage signal connected to one and the second voltage signal connected to the other correspond to the same battery; the two associated multiplexers respectively output the first voltage signal and the second voltage signal corresponding to the same battery according to the control signals respectively received; and the voltage measurement units corresponding to the two associated multiplexers respectively measure the first voltage signal and the second voltage signal.

[0068] The fault location in the battery voltage detection circuit is determined according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries.

[0069] In this embodiment, judging the fault location in the battery voltage detection circuit according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries includes:

[0070] If the first voltage signal and the second voltage signal measured within a sampling period are equal, it is determined that the first voltage conversion unit outputting the first voltage signal, the second voltage conversion unit outputting the second voltage signal, and the two voltage measurement units detecting the first voltage signal and the second voltage signal are all normal.

[0071] In one embodiment, if in two associated multiplexers, a first voltage signal connected to the first selector input terminal of one and a second voltage signal connected to the second selector input terminal of the other correspond to the same battery, and a second voltage signal connected to the second selector input terminal of one and a first voltage signal connected to the first selector input terminal of the other correspond to the same battery, then the two voltage detection units corresponding to the two multiplexers respectively detect the voltages of the corresponding two batteries within two sampling periods, that is, the two voltage detection units cross-detect the voltages of the corresponding two batteries.

[0072] If the first voltage signal measured in one sampling period is the same as the second voltage signal, and the first voltage signal measured in another sampling period is different from the second voltage signal, it is determined that one or both of the first voltage conversion unit and the second voltage conversion unit used in the other sampling period is faulty.

[0073] If the first voltage signal and the second voltage signal measured in the two sampling periods are different, it is determined that one or both of the two voltage measurement units corresponding to the two multiplexers are faulty.

[0074] The following combination Figure 2 , taking a battery voltage detection circuit that detects two batteries as an example, a fault judgment method in a battery voltage detection circuit including two batteries is explained.

[0075] Please refer to Figure 2 The first first voltage conversion unit VC1 is used to convert the first battery voltage V1 into a first first voltage signal V11, the first second voltage conversion unit CB1 is used to convert the first battery voltage V1 into a first second voltage signal V12, the second first voltage conversion unit VC2 is used to convert the second battery voltage V2 into a second first voltage signal V21, and the second second voltage conversion unit CB2 is used to convert the second battery voltage V2 into a second second voltage signal V22. The first first voltage signal V11 and the second second voltage signal V22 are respectively output to the first selector input terminal and the second selector input terminal of the first multiplexer MUX1, the second first voltage signal V21 and the first second voltage signal V12 are respectively output to the first selector input terminal and the second selector input terminal of the second multiplexer MUX2, the first multiplexer MUX1 is connected to the first voltage measurement unit ADC1, and the second multiplexer MUX2 is connected to the second voltage measurement unit ADC2.

[0076] When the control signal received by the two multiplexers is 0, the first voltage signal / second voltage signal received by the corresponding first selector input terminal is output; when the control signal received by the two multiplexers is 1, the first voltage signal / second voltage signal received by the corresponding second selector input terminal is output, that is, if the control signal received by the first multiplexer MUX1 is 0, the first multiplexer MUX1 outputs the first first voltage signal V11 to the first voltage measurement unit ADC1; if the control signal received by the first multiplexer MUX1 is 1, the first multiplexer MUX1 outputs the second second voltage signal V22 to the first voltage measurement unit ADC1; if the control signal received by the second multiplexer MUX2 is 0, the second multiplexer MUX2 outputs the second first voltage signal V21 to the second voltage measurement unit ADC2; if the control signal received by the second multiplexer MUX2 is 1, the second multiplexer MUX2 outputs the first second voltage signal V12 to the second voltage measurement unit ADC2.

[0077] Therefore, in the first sampling cycle, the control signal input to the first multiplexer MUX1 is 0, and the control signal input to the second multiplexer MUX2 is 1, then the first voltage measurement unit ADC1 and the second voltage measurement unit ADC2 are respectively used to measure the first first voltage signal V11 and the first second voltage signal V12 corresponding to the first battery. At this time, when the results measured by the two voltage measurement units are the same, it means that the two voltage measurement units and the first first voltage conversion unit VC1, the second second voltage conversion unit CB1, the first voltage measurement unit ADC1 and the second voltage measurement unit ADC2 corresponding to the first battery are all normal. Similarly, in the second sampling period, the control signal input to the first multiplexer MUX1 is 1, and the control signal input to the second multiplexer MUX2 is 0, then the first voltage measurement unit ADC1 and the second voltage measurement unit ADC2 are respectively used to measure the second first voltage signal V21 and the second second voltage signal V22 corresponding to the second battery. At this time, when the results measured by the two voltage measurement units are the same, it means that the two voltage measurement units and the second first voltage conversion unit VC2 corresponding to the second battery, the second second voltage conversion unit CB2, the first voltage measurement unit ADC1 and the second voltage measurement unit ADC2 are all normal.

[0078] If the two measurement results in the first sampling cycle are the same, while the two measurement results in the second sampling cycle are different, it is judged that the fault location is in one or both of the second first voltage conversion unit VC2 and the second second voltage conversion unit CB2; if the two measurement results in the second sampling cycle are the same, while the two measurement results in the first sampling cycle are different, it is judged that the fault location is in one or both of the first first voltage conversion unit VC1 and the first second voltage conversion unit CB1; if the two measurement results in the first sampling cycle are different, and the two measurement results in the second sampling cycle are different, it is judged that the fault location is in one or both of the first voltage measurement unit ADC1 and the second voltage measurement unit ADC2.

[0079] If the voltage of 2M batteries connected in series is to be detected, each two adjacent batteries in the 2M batteries are divided into a group, with a total of M groups, and each group corresponds to a battery voltage detection circuit including two batteries. The two voltage measurement units in each battery voltage detection circuit cross-detect the corresponding two battery voltages. Therefore, when M battery voltage detection circuits including two batteries are detected at the same time, only two sampling cycles are needed to diagnose the faults of the M battery voltage detection circuits, and M is a positive integer.

[0080] Of course, in other embodiments, N may also be an integer of 3 or greater.

[0081] In another embodiment, N=3 is used as an example for explanation. Specifically, if among the three associated multiplexers, one multiplexer accesses the first voltage signal and the second voltage signal corresponding to different batteries, and the other two multiplexers respectively access the first voltage signal and the second voltage signal corresponding to different batteries, the second voltage signal accessed by one of the other multiplexers corresponds to the same battery as the first voltage signal accessed by one of the multiplexers, and the first voltage signal accessed by another of the other multiplexers corresponds to the same battery as the second voltage signal accessed by one of the multiplexers, then when in one sampling period, the two voltage measurement results corresponding to the two multiplexers whose output terminal voltages correspond to the same battery are the same, and in another sampling period, the two voltage measurement results corresponding to the two multiplexers whose output terminal voltages correspond to the same battery are different, it is determined that the fault location is one, two or three of the voltage measurement units corresponding to the first voltage conversion unit, the second voltage conversion unit and one of the other two multiplexers used in the other sampling period.

[0082] Figure 3 The circuit structure of a battery voltage detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 2 .

[0083] The following combination Figure 3 , taking a battery voltage detection circuit that detects three batteries as an example, a fault judgment method in a battery voltage detection circuit that includes three batteries is explained.

[0084] Please refer to Figure 3 The first first voltage conversion unit VC3 is used to convert the first battery voltage V1 into a first first voltage signal V11, the first second voltage conversion unit CB3 is used to convert the first battery voltage V1 into a first second voltage signal V12, the second first voltage conversion unit VC4 is used to convert the second battery voltage V2 into a second first voltage signal V21, the second second voltage conversion unit CB4 is used to convert the second battery voltage V2 into a second second voltage signal V22, the third first voltage conversion unit VC5 is used to convert the third battery voltage V3 into a third first voltage signal V31, and the third second voltage conversion unit CB5 is used to convert the third battery voltage V3 into a third second voltage signal V32. The first first voltage signal V11 and the second second voltage signal V22 are output to the first selector input terminal and the second selector input terminal of the first multiplexer MUX3 respectively, the second first voltage signal V21 and the third second voltage signal V32 are output to the first selector input terminal and the second selector input terminal of the second multiplexer MUX4 respectively, the third first voltage signal V31 and the first second voltage signal V12 are output to the first selector input terminal and the second selector input terminal of the third multiplexer MUX5 respectively, the first multiplexer MUX3 is connected to the first voltage measurement unit ADC3, the second multiplexer MUX4 is connected to the second voltage measurement unit ADC4, and the third multiplexer MUX5 is connected to the third voltage measurement unit ADC5.

[0085] When the control signal received by the two multiplexers is set to 0, the first voltage signal / second voltage signal received by the corresponding first selector input terminal is output; when the control signal received by the two multiplexers is 1, the first voltage signal / second voltage signal received by the corresponding second selector input terminal is output, that is, if the control signal received by the first multiplexer MUX3 is 0, the first multiplexer MUX3 outputs the first first voltage signal V11 to the first voltage measurement unit ADC3; if the control signal received by the first multiplexer MUX3 is 1, the first multiplexer MUX3 outputs the second second voltage signal V22 to the first voltage measurement unit ADC3; if the second multiplexer MUX4 If the control signal received is 0, the second multiplexer MUX4 outputs the second first voltage signal V21 to the second voltage measurement unit ADC4; if the control signal received by the second multiplexer MUX4 is 1, the second multiplexer MUX4 outputs the third second voltage signal V32 to the second voltage measurement unit ADC4; if the control signal received by the third multiplexer MUX5 is 0, the third multiplexer MUX5 outputs the third first voltage signal V31 to the third voltage measurement unit ADC5; if the control signal received by the third multiplexer MUX5 is 1, the third multiplexer MUX5 outputs the first second voltage signal V12 to the third voltage measurement unit ADC5.

[0086] Therefore, in the first sampling period, the control signal input to the first multiplexer MUX3 is 0, and the control signal input to the third multiplexer MUX5 is 1. Then, the first voltage measurement unit ADC3 and the third voltage measurement unit ADC5 are respectively used to measure the first first voltage signal V11 and the first second voltage signal V12 corresponding to the first battery. At this time, when the measurement results of the two voltage measurement units are the same, it indicates that both the two voltage measurement units and the first voltage conversion unit and the second voltage conversion unit corresponding to the first battery are normal. In the second sampling period, the control signal input to the first multiplexer MUX3 is 1, and the control signal input to the second multiplexer MUX4 is 0. Then, the first voltage measurement unit ADC3 and the second voltage measurement unit ADC4 are respectively used to measure the second second voltage signal V22 and the second first voltage signal V21 corresponding to the second battery. At this time, when the measurement results of the two voltage measurement units are the same, it indicates that both the two voltage measurement units and the second first voltage conversion unit VC4 and the second second voltage conversion unit CB4 corresponding to the first battery are normal. In the third sampling period, the control signal input to the third multiplexer MUX5 is 0, and the control signal input to the second multiplexer MUX4 is 1. Then, the third voltage measurement unit ADC5 and the second voltage measurement unit ADC4 are respectively used to measure the third first voltage signal V31 and the third second voltage signal V32 corresponding to the third battery. At this time, when the measurement results of the two voltage measurement units are the same, it indicates that both the two voltage measurement units and the third first voltage conversion unit VC5 and the third second voltage conversion unit CB5 corresponding to the third battery are normal.

[0087] If the measurement results in the first sampling period are the same, the measurement results in the third sampling period are the same, but the measurement results in the second sampling period are different, then it is determined that the fault location is in one or both of the second first voltage conversion unit VC4 and the second second voltage conversion unit CB4. If the measurement results in the first sampling period are the same, the measurement results in the second sampling period are different, and the measurement results in the third sampling period are different, then it is determined that the fault location is in the second voltage measurement unit ADC4.

[0088] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A battery voltage detection circuit for detecting the voltage of N batteries connected in series, where N is a positive integer greater than 1, characterized in that: include: A first voltage conversion module, the first voltage conversion module is used to convert the voltages at both ends of N batteries into N first voltage signals for output, wherein the voltage value of the first voltage signal is smaller than the voltage at both ends of the corresponding battery; A second voltage conversion module, the second voltage conversion module is used to convert the voltages at both ends of the N batteries into N second voltage signals for output, wherein the voltage value of the second voltage signal is smaller than the voltage at both ends of the corresponding battery; N multiplexers, the multiplexers are used to output the first voltage signal or the second voltage signal connected to the multiplexer according to the control signal received by the multiplexer, the multiplexer includes a selector control end, a first selector input end, a second selector input end and a selector output end, the selector control end is used to connect the control signal, the first selector input end is used to connect one of the first voltage signals, the second selector input end is used to connect one of the second voltage signals, in the same multiplexer, the connected first voltage signal and the second voltage signal correspond to different batteries respectively, and the selector output end is used to output the connected first voltage signal or the second voltage signal as the output end voltage; N voltage measuring units, the N voltage measuring units correspond one-to-one to the N multiplexers, and each voltage measuring unit is used to measure the output terminal voltage of the corresponding multiplexer.

2. The battery voltage detection circuit according to claim 1, characterized in that: The first voltage conversion module includes N first voltage conversion units, the N first voltage conversion units correspond to the N batteries one by one, each of the first voltage conversion units is used to convert the voltage at both ends of a battery into a first voltage signal output, the first voltage conversion unit has a first voltage input terminal, a second voltage input terminal and a first voltage signal output terminal, the first voltage input terminal is coupled to the positive electrode of the corresponding battery, and the second voltage input terminal is coupled to the negative electrode of the corresponding battery; The second voltage conversion module includes N second voltage conversion units, and the N second voltage conversion units correspond one-to-one to the N batteries. Each second voltage conversion unit is used to convert the voltage across a battery into a second voltage signal output. The second voltage conversion unit has a third voltage input terminal, a fourth voltage input terminal and a second voltage signal output terminal. The third voltage input terminal is coupled to the positive pole of the corresponding battery, and the fourth voltage input terminal is coupled to the negative pole of the corresponding battery.

3. The battery voltage detection circuit according to claim 2, characterized in that: Also includes: (N+1) first resistors, the first end of the (N+1) first resistors is connected to the positive electrodes of the N batteries and the negative electrode of the Nth battery, the second end of the (N+1) first resistors is connected to the first voltage input ends or the second voltage input ends of the N first voltage conversion units, the first voltage input end of the first first voltage conversion unit is connected to the second end of the first first resistor, the second voltage input end of the i-th first voltage conversion unit and the first voltage input end of the (i+1)-th first voltage conversion unit are commonly connected to the second end of the (i+1)-th first resistor, the second voltage input end of the N-th first voltage conversion unit is connected to the second end of the (N+1)-th first resistor, i is a positive integer, and 1≤i≤N-1; (N+1) second resistors, the first end of the (N+1) second resistors is connected to the positive electrodes of the N batteries and the negative electrode of the Nth battery, the second end of the (N+1) second resistors is connected to the third voltage input end or the fourth voltage input end of the N second voltage conversion units, the third voltage input end of the first second voltage conversion unit is connected to the second end of the first second resistor, the fourth voltage input end of the i-th second voltage conversion unit and the third voltage input end of the (i+1)-th second voltage conversion unit are commonly connected to the second end of the (i+1)-th second resistor, and the fourth voltage input end of the N-th second voltage conversion unit is connected to the second end of the (N+1)-th second resistor; N first capacitors, the N first capacitors correspond one-to-one to the N first voltage conversion units, and two ends of the first capacitors are respectively connected to a corresponding first voltage input terminal and a second voltage input terminal; N second capacitors, the N second capacitors correspond one-to-one to the N second voltage conversion units, and two ends of the second capacitors are respectively connected to the corresponding third voltage input terminal and fourth voltage input terminal.

4. The battery voltage detection circuit according to claim 1, characterized in that: The voltage measuring unit includes an analog-to-digital converter.

5. A fault diagnosis method, characterized in that: Using the battery voltage detection circuit according to any one of claims 1 to 4, the fault diagnosis method comprises: Convert the voltages at both ends of the N batteries into N first voltage signal outputs; Convert the voltages at both ends of the N batteries into N second voltage signal outputs; Performing N sampling cycles to measure the first voltage signal and the second voltage signal corresponding to each battery in the N batteries, the method for performing any one of the N sampling cycles comprising: inputting corresponding control signals to two associated multiplexers respectively, wherein the first voltage signal connected to one of the two associated multiplexers and the second voltage signal connected to the other of the two associated multiplexers correspond to the same battery; the two associated multiplexers respectively output the first voltage signal and the second voltage signal corresponding to the same battery according to the control signals received respectively; the voltage measurement units corresponding to the two associated multiplexers respectively measure the first voltage signal and the second voltage signal; The fault location in the battery voltage detection circuit is determined according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries.

6. The fault diagnosis method according to claim 5, characterized in that: Determining a fault location in the battery voltage detection circuit according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries includes: If the first voltage signal and the second voltage signal measured within a sampling period are equal, it is determined that the first voltage conversion unit outputting the first voltage signal, the second voltage conversion unit outputting the second voltage signal, and the two voltage measurement units detecting the first voltage signal and the second voltage signal are all normal.

7. The fault diagnosis method according to claim 6, characterized in that: Determining a fault location in the battery voltage detection circuit according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries, further comprising: If, in two associated multiplexers, a first voltage signal connected to the first selector input terminal of one and a second voltage signal connected to the second selector input terminal of the other correspond to the same battery, and the second voltage signal connected to the second selector input terminal of the one and the first voltage signal connected to the first selector input terminal of the other correspond to the same battery, then the two voltage detection units corresponding to the two multiplexers respectively detect the voltages of the corresponding two batteries within two sampling periods; If the first voltage signal and the second voltage signal measured in one sampling period are the same, and the first voltage signal and the second voltage signal measured in another sampling period are different, it is determined that one or both of the first voltage conversion unit and the second voltage conversion unit used in the another sampling period are faulty; If the first voltage signal and the second voltage signal measured in the two sampling periods are different, it is determined that one or both of the two voltage measurement units corresponding to the two multiplexers are faulty.

8. The fault diagnosis method according to claim 6, characterized in that: Determining a fault location in the battery voltage detection circuit according to the measured first voltage signal and the second voltage signal corresponding to each battery in the N batteries, further comprising: If, among the three associated multiplexers, one multiplexer receives a first voltage signal and a second voltage signal corresponding to different batteries, and the other two multiplexers receive first voltage signals and second voltage signals corresponding to different batteries respectively, the second voltage signal received by one of the other multiplexers corresponds to the same battery as the first voltage signal received by the one multiplexer, and the first voltage signal received by another of the other multiplexers corresponds to the same battery as the second voltage signal received by the one multiplexer, then when in one sampling period, the two voltage measurement results corresponding to the two multiplexers whose output terminal voltages correspond to the same battery are the same, and in another sampling period, the two voltage measurement results corresponding to the two multiplexers whose output terminal voltages correspond to the same battery are different, it is judged that the fault location lies in one, two or three of the voltage measurement units corresponding to the first voltage conversion unit, the second voltage conversion unit and one of the other two multiplexers used in the other sampling period.

9. An electronic device, characterized in that: The invention comprises a battery voltage detection circuit as claimed in any one of claims 1 to 4.

Images