A voltage measurement circuit and method, a circuit board and a control module

Abstract

The embodiment of the application provides a voltage measurement circuit and method, a circuit board and a control module. The circuit is used for measuring the voltage output by a battery, the battery comprising n battery cells connected in series, wherein n is an integer greater than 1; the circuit comprises n low-voltage measurement modules corresponding to the n battery cells, a first switch circuit, a second switch circuit, a reference voltage source and a control module, wherein the reference voltage source is used for outputting a preset reference voltage; the two ends of each low-voltage measurement module are connected to the two ends of the corresponding battery cell through the first switch circuit, and the two ends of each low-voltage measurement module are also connected to the two ends of the reference voltage source through the second switch circuit; the control module is connected to the switch units in the first switch circuit and the second switch circuit, and the control module is also connected to each low-voltage measurement module. The application can balance the wide-range measurement and the measurement accuracy.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a voltage measurement circuit and method, circuit board and control module. Background Technology

[0002] In the field of voltage measurement, technicians typically use instruments such as multimeters and voltmeters to measure voltage. However, these traditional measuring instruments cannot simultaneously balance range and accuracy. To measure a large range of voltage, the measurement accuracy must be reduced; to improve the measurement accuracy, only a small range of voltage can be measured.

[0003] Currently, the problem of high-precision measurement of large-range voltages urgently needs to be solved. Summary of the Invention

[0004] This application provides a voltage measurement circuit and method, a circuit board and a control module, which can balance large-range measurement and measurement accuracy.

[0005] The embodiments of this application are implemented as follows:

[0006] In a first aspect, embodiments of this application provide a voltage measurement circuit for measuring the voltage output of a battery. The battery includes n cells connected in series, where n is an integer greater than 1. The circuit includes: n low-voltage measurement modules corresponding one-to-one with the n cells, a first switching circuit, a second switching circuit, a reference voltage source, and a control module. The reference voltage source is used to output a preset reference voltage. The two ends of each low-voltage measurement module are connected to the two ends of the corresponding cell through the first switching circuit, and the two ends of each low-voltage measurement module are also connected to the two ends of the reference voltage source through the second switching circuit. The control module is connected to the switching units in the first and second switching circuits, and is also connected to each low-voltage measurement module. The control module is used to control the switching units to be turned on or off, and to acquire the voltage measured by each low-voltage measurement module for each cell.

[0007] In the technical solution of this application embodiment, since the low-voltage measurement module has a small measurement range but high measurement accuracy, n low-voltage measurement modules can measure the voltage across the n cells in the battery respectively, and the measured voltages are accumulated to obtain the battery output voltage. This expands the measurement range of the voltage measurement circuit and ensures that the accuracy of the accumulated voltage measurement is close to that of the low-voltage measurement module, thus achieving a balance between large measurement range and high measurement accuracy. Furthermore, this application embodiment can also utilize a reference voltage source to calibrate each low-voltage measurement module, further improving the accuracy of the voltage measurement equipment.

[0008] In some embodiments, the first switching circuit includes n+1 first switching units; n-1 connection nodes formed by n low-voltage measurement modules connected in series and the two ends of the branch formed by n low-voltage measurement modules connected in series are used as first connectable nodes; n-1 connection nodes formed by n battery cells connected in series and the two ends of the branch formed by n battery cells connected in series are used as second connectable nodes; each first connectable node is connected to the corresponding second connectable node through a first switching unit.

[0009] In the above embodiments, a specific circuit structure for the first switching circuit is provided.

[0010] In some embodiments, the second switching circuit includes n+2 second switching units; n-1 connection nodes formed by the n second switching units connected in series and the two ends of the branch formed by the n second switching units connected in series are used as third connectable nodes, each first connectable node is connected to the corresponding third connectable node through the second switching unit, and the two ends of the branch formed by the second switching units connected in series are also connected to the two ends of the reference voltage source through the second switching unit.

[0011] In the above embodiments, a specific circuit structure for the second switching circuit is provided.

[0012] In some embodiments, the second switching circuit includes 2n second switching units; both ends of the n low-voltage measurement modules are connected to the two ends of the reference voltage source through the second switching units.

[0013] In the above embodiments, another specific circuit structure of the second switching circuit is provided, which allows each low-voltage measurement module to simultaneously measure the voltage across the reference voltage source, reducing the time required to obtain the error values ​​corresponding to each low-voltage measurement module.

[0014] In some embodiments, the control module is specifically used to control each switching unit in the second switching circuit, such that when each low-voltage measurement module is disconnected from the reference voltage source, it controls each switching unit in the first switching circuit and measures the voltage U1, U2, ..., U of the corresponding battery cell through each low-voltage measurement module. n The control module is also used to control each switching unit in the first switching circuit, so that when each low-voltage measurement module is disconnected from each cell, it controls each switching unit in the second switching circuit, and respectively measures the voltages V1, V2, ..., V output from the reference voltage source through each low-voltage measurement module. n The control module is also used to calculate V1, V2, ..., V respectively. n The error σ of each low-voltage measurement module is obtained from the difference between the voltage and the preset reference voltage. v1 , σ v2 , ..., σ vn And according to σv1 , σ v2 , ..., σ vn For U1, U2,...,U n After calibration, we obtain U1', U2', ..., U n Then add up U1', U2', ..., U n 'The obtained U sum , which is the measured voltage output of the battery.

[0015] In the above embodiments, a specific control method for the control module is provided.

[0016] In some embodiments, the voltage measurement circuit further includes a high-voltage measurement module, the two ends of which are connected to the two ends of the battery, and the control module is also connected to the high-voltage measurement module; the high-voltage measurement module is used to measure the voltage output by the battery to obtain V. total The control module is specifically used in |V total -U sum When the error exceeds the allowable error of the high-voltage measurement module, U sum The measured voltage output of the battery.

[0017] In the above embodiments, to avoid continuous changes in the measured value due to the excessively high accuracy of the low-voltage measurement module, the measurement circuit also includes a lower-accuracy high-voltage measurement module to directly measure the voltage output by the battery. Only the voltage V measured by the high-voltage measurement module is considered accurate. total with U sum The U measured by the low-voltage measurement module is only used when the absolute value of the difference is greater than the allowable error of the high-voltage measurement module. sum The measured voltage output of the battery.

[0018] In some embodiments, the control module is further specifically used for |σ vN |>σ allow , and σ vN When ≥0, according to formula U N '=U N -|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |>σ allow , and σ vN When <0, according to formula U N '=U N +|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |≤σ allow At that time, U N '=U NTo obtain U1', U2', ..., U n '; where σ allow The allowable error for each low-voltage measurement module is set; N is any integer from 1 to n.

[0019] In the above embodiments, U1, U2, ..., U n One specific implementation method for calibration.

[0020] In some embodiments, σ allow The first permissible error is the smaller of the first and second permissible errors, where the first permissible error is the maximum permissible error of each low-voltage measurement module, and the second permissible error is |σ|. vtotal | / n,|σ vtotal | represents the maximum permissible error of the high-voltage measurement module.

[0021] In the above embodiments, the allowable error σ for the low-voltage measurement module is set. allow Specifically, it is the smaller of the maximum permissible error of the low-voltage measurement module and the second permissible error allocated to each low-voltage measurement module from the maximum permissible error of the high-voltage measurement module. Thus, when the error satisfies σ... allow At that time, it will definitely be able to meet the error requirements of both the low-voltage measurement module and the high-voltage measurement module.

[0022] In some embodiments, the control module is also connected to a reference voltage source, and the control module is further configured to set a preset reference voltage V. REF = (V1+V2+…+V n ) / n.

[0023] In the above embodiments, preset reference voltages are set as V1, V2, ..., V n The average value can make the preset reference voltage close to the voltage range of each cell, reducing the adjustment range of each low-voltage measuring device and the time spent on adjustment.

[0024] Secondly, embodiments of this application provide a voltage measurement method based on the control module in any of the voltage measurement circuits described above. The method includes: controlling the switching units in the first and second switching circuits to be turned on or off, and acquiring the voltage of each cell measured by each low-voltage measurement module.

[0025] In some embodiments, controlling the switching units in the first and second switching circuits to be turned on or off, and obtaining the voltage of each cell measured by each low-voltage measurement module, includes: controlling each switching unit in the second switching circuit so that each low-voltage measurement module is disconnected from the reference voltage source, controlling each switching unit in the first switching circuit, and obtaining the voltage U1, U2, ..., U of the corresponding cell through each low-voltage measurement module. n The method further includes: controlling each switching unit in the first switching circuit so that each low-voltage measurement module is disconnected from each battery cell, then controlling each switching unit in the second switching circuit, and measuring the voltages V1, V2, ..., V output from the reference voltage source through each low-voltage measurement module. n Calculate V1, V2, ..., V respectively. n The error σ of each low-voltage measurement module is obtained by measuring the difference between the voltage and the preset reference voltage output from the reference voltage source. v1 , σ v2 , ..., σ vn According to σ v1 , σ v2 , ..., σ vn For U1, U2,...,U n After calibration, we obtain U1', U2', ..., U n '; will accumulate U1', U2', ..., U n 'The obtained U sum , which is the measured voltage output of the battery.

[0026] In some embodiments, the voltage measurement circuit further includes a high-voltage measurement module, the two ends of which are connected to the two ends of the battery. A control module is also connected to the high-voltage measurement module. The high-voltage measurement module is used to measure the voltage output by the battery to obtain V. total The sum of U1', U2', ..., U will be accumulated. n 'The obtained U sum The measured battery output voltage includes: in |V total -U sum When the error exceeds the allowable error of the high-voltage measurement module, U sum The measured voltage output of the battery.

[0027] In some embodiments, according to σ v1 , σ v2 , ..., σ vn For U1, U2,...,U n After calibration, we obtain U1', U2', ..., U n ', including: in |σ vN |>σallow , and σ vN When ≥0, according to formula U N '=U N -|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |>σ allow , and σ vN When <0, according to formula U N '=U N +|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |≤σ allow At that time, U N '=U N To obtain U1', U2', ..., U n '; where σ allow Allowable error settings for each low-voltage measurement module: N is any integer from 1 to n.

[0028] In some embodiments, σ allow The first permissible error is the smaller of the first and second permissible errors, where the first permissible error is the maximum permissible error of each low-voltage measurement module, and the second permissible error is |σ|. vtotal | / n,|σ vtotal | represents the maximum permissible error of the high-voltage measurement module.

[0029] In some embodiments, the control module is also connected to a reference voltage source, and the control module is further configured to set a preset reference voltage V. REF = (V1+V2+…+V n ) / n.

[0030] Thirdly, embodiments of this application provide a circuit board including the voltage measurement circuit described in the above embodiments.

[0031] Fourthly, embodiments of this application provide a control module, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the voltage measurement method described above.

[0032] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0034] Figure 1 This is a circuit diagram of a voltage measurement circuit disclosed in one embodiment of this application. Figure 1 ;

[0035] Figure 2 This is a circuit diagram of a voltage measurement circuit disclosed in one embodiment of this application. Figure 2 ;

[0036] Figure 3 This is a circuit diagram of a voltage measurement circuit disclosed in one embodiment of this application. Figure 3 ;

[0037] Figure 4 This is a schematic flowchart of a voltage measurement method disclosed in an embodiment of this application;

[0038] Figure 5 This is a block diagram of a control module disclosed in an embodiment of this application;

[0039] The accompanying drawings are not drawn to scale.

[0040] Labeling Explanation: Battery-1, First Switching Circuit-2, Second Switching Circuit-3, Reference Voltage Source-4, High Voltage Measurement Module-5, Cell-C1-C n Low voltage measurement module - V1-V n First switching unit -S0-S n Second switching unit -A0-A n+1 / A0-A 2n-1 . Detailed Implementation

[0041] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0042] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0043] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0045] In the field of voltage measurement, technicians typically use instruments such as multimeters and voltmeters to measure voltage. However, these traditional measuring instruments cannot simultaneously balance range and accuracy. To measure a large voltage range, the measurement accuracy must be reduced; to improve the measurement accuracy, only a small voltage range can be measured. Currently, the problem of high-precision measurement of large voltage ranges urgently needs to be solved.

[0046] With the rapid development of the new energy industry, battery systems are increasingly used as energy storage and release devices, and battery voltage is one of the most fundamental monitoring parameters of a battery system. Battery voltage can be used for high-voltage fault diagnosis, relay diagnosis, charge and discharge management, and battery safety early warning. The realization of these functions relies on accurate and reliable voltage measurements. However, currently, there is a lack of necessary continuous monitoring and correction for changes in the accuracy of voltage measurements, resulting in low reliability.

[0047] For example, the batteries used in new energy vehicles are usually composed of multiple cells connected in series and parallel. The battery voltage is usually high, so a large-range measuring instrument is needed for measurement. However, the accuracy of a large-range measuring instrument is low, making it difficult to meet the accuracy requirements for measuring battery voltage.

[0048] Based on the above problems, this application proposes the following technical concept: For a battery formed by multiple cells connected in series, specifically, multiple low-voltage measurement modules with small ranges but high precision are used to measure the voltage of each cell separately, and the measured voltages of each cell are summed to obtain the battery's measured voltage, thus balancing a large measurement range and high precision. In some embodiments, a reference voltage source with higher precision than the low-voltage measurement modules can be used to calibrate each low-voltage measurement module to further ensure the measurement accuracy of the voltage measurement circuit. In some embodiments, to avoid continuous changes in the measured value due to excessively high precision of the low-voltage measurement modules, a high-voltage measurement module with a large range but low precision can be set to directly measure the battery voltage, and the battery's measured voltage calculated by the low-voltage measurement modules can be used as a standard. When the measurement error of the high-voltage measurement modules is too large, the high-voltage measurement modules are calibrated; when the measurement error of the high-voltage measurement modules is within the allowable range, the measurement results of the high-voltage measurement modules are directly used.

[0049] This application provides a voltage measurement circuit for measuring the voltage output by a battery. Please refer to [reference needed]. Figure 1 Battery 1 consists of n cells C1-C1 connected in series. n Where n is an integer greater than 1; the voltage measurement circuit includes: connected to n battery cells C1-U n A one-to-one correspondence is set up with n low-voltage measurement modules V1-V n The system comprises a first switching circuit 2, a second switching circuit 3, a reference voltage source 4, and a control module (not shown in the attached figure). The reference voltage source 4 is used to output a preset reference voltage. The two ends of each low-voltage measurement module are connected to the two ends of the corresponding battery cell through the first switching circuit 2. The two ends of each low-voltage measurement module are also connected to the two ends of the reference voltage source 4 through the second switching circuit 3. The control module is connected to the switching units in the first switching circuit 2 and the second switching circuit 3. The control module is also connected to each low-voltage measurement module (the control module and the connection between the control module and each low-voltage measurement module are not shown in the figure).

[0050] The control module is used to control the switching units in the first switching circuit 2 and the second switching circuit 3 to be turned on or off, and to obtain the voltage of each cell measured by each low-voltage measurement module.

[0051] The implementation details of the voltage measurement circuit in this embodiment are described below. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0052] The low-voltage measurement module can be a voltage sensor with a small range, such as a voltmeter with a small range.

[0053] The reference voltage source can be a programmable high-precision reference voltage source generation module, which can generate high-precision reference voltages of different values ​​according to actual needs. These voltage values ​​can be adjusted through programming.

[0054] The first switching circuit and the second switching circuit are respectively circuits formed by multiple switching units connected in series and / or in parallel, wherein the switching units are, for example, knife switches or relays.

[0055] Specifically, the low-voltage measurement module is connected to the corresponding battery cell via a first switching circuit, and also connected to a reference voltage source via a second switching circuit. The control module can control whether the low-voltage measurement module measures the voltage of the battery cell or the voltage of the reference voltage source by controlling the on and off states of the switching units in the first and second switching circuits. When the control module only controls the connection between the low-voltage measurement module and the battery cell, the low-voltage measurement module measures the voltage of the battery cell. When the control module only controls the connection between the low-voltage measurement module and the reference voltage source, the low-voltage measurement module measures the voltage of the reference voltage source. In this case, the output voltage of the reference voltage source and the voltage measured by the low-voltage measurement module can be used to calibrate the low-voltage measurement module.

[0056] In this embodiment, because the low-voltage measurement module has a small measurement range but high measurement accuracy, n low-voltage measurement modules can be used to measure the voltage across the n cells in the battery respectively, and the measured voltages are accumulated to obtain the battery output voltage. This expands the measurement range of the voltage measurement circuit while ensuring that the accuracy of the accumulated voltage measurement is close to that of the low-voltage measurement module, thus achieving a balance between large measurement range and high measurement accuracy. Furthermore, this embodiment can also utilize a reference voltage source to calibrate each low-voltage measurement module, further improving the accuracy of the voltage measurement equipment.

[0057] In some embodiments, please refer to Figure 1 The first switching circuit 2 includes n+1 first switching units S0-S1 n .

[0058] n low-voltage measurement modules V1-V n The system consists of n-1 connection nodes and n low-voltage measurement modules V1-V connected in series. n The two ends of the branch formed by series connection are used as the first connectable nodes, connecting n cells C1-C n The series connection forms n-1 connection nodes and n cells C1-C nThe two ends of the branch formed by series connection serve as the second connectable nodes, and each first connectable node is connected to the corresponding second connectable node through the first switch unit.

[0059] On a branch formed by n low-voltage measurement modules connected in series, there will be n-1 connection nodes. A connection node can be considered as a node on the connecting line between any two connected low-voltage measurement modules on the branch. The first connectable nodes include these n-1 connection nodes, as well as the two endpoints of the branch formed by the n low-voltage measurement modules connected in series (as two nodes). Therefore, there are a total of n+1 first connectable nodes.

[0060] On a branch formed by n battery cells connected in series, there will be n-1 connection nodes. A connection node can be considered as a node on the connecting line between any two connected battery cells on the branch. The second connectable nodes include these n-1 connection nodes, as well as the two endpoints of the branch formed by the n battery cells connected in series (as two nodes). Therefore, there are a total of n+1 second connectable nodes.

[0061] In some embodiments, the two ends of the low-voltage measurement module can also be connected to the two ends of the corresponding battery cell via two first switching units. For example, the two ends of V1 are connected to the two ends of C1 via first switching units S0 and S1, the two ends of V2 are connected to the two ends of C2 via first switching units S1 and S2, and so on. n The two ends are connected through the first switching unit S n-1 and S n Connected to C n The two ends.

[0062] The control module can connect the low-voltage measurement modules V1-V by controlling the conduction of each first switch unit. n and the corresponding battery cell C1-C n This enables the low-voltage measurement module V1-V n The corresponding cell C1-C can be measured. n The voltage.

[0063] In the above embodiments, a specific circuit structure for the first switching circuit is provided.

[0064] In some embodiments, please refer to Figure 1 The second switching circuit 3 includes n+2 second switching units A0-A n+1 .

[0065] The n-1 connection nodes formed by n second switch units connected in series and the two ends of the branch formed by n second switch units connected in series are used as third connectable nodes. Each first connectable node is connected to the corresponding third connectable node through a second switch unit. The two ends of the branch formed by the second switch units connected in series are also connected to the two ends of the reference voltage source 4 through a second switch unit.

[0066] On a branch formed by n second switch units connected in series, there will be n-1 connection nodes. A connection node can be considered as a node on the connecting line between any two connected second switch units on the branch. The third connectable nodes include these n-1 connection nodes, as well as the two endpoints of the branch formed by the n second switch units connected in series (as two nodes). Therefore, there are a total of n+1 third connectable nodes.

[0067] For example, the control module can specifically connect the series circuit between the low-voltage measurement module V1 and the reference voltage source 4 by controlling all second switch units except A1 to be turned on and only A1 to be turned off. This allows the low-voltage measurement module V1 to measure the output voltage of the reference voltage source 4. Then, by comparing the measured voltage of the low-voltage measurement module V1 with the preset output voltage of the reference voltage source 4, the control module V1 can adjust its voltage. t Calibration is then performed. Similarly, the control module can connect the series circuit between the low-voltage measurement module V2 and the reference voltage source 4 by controlling all second switch units except A2 to be turned on and only A2 to be turned off, thereby calibrating the low-voltage measurement module V2. This process can be repeated for low-voltage measurement modules V1-V2. n All circuits are calibrated to improve the accuracy of battery voltage measurement.

[0068] In the above embodiments, a specific circuit structure for the second switching circuit is provided.

[0069] In some embodiments, please refer to Figure 2 The second switching circuit includes 2n second switching units A0-A 2n-1 n low-voltage measurement modules V1-V n Both ends of the circuit are connected to the reference voltage source 4 via the second switching unit.

[0070] Specifically, the control module can connect the low-voltage measurement modules V1-V by activating each of the second switching units. n The series circuit with reference voltage source 4 is used by the low-voltage measurement module V1-V n The output voltage of reference voltage source 4 is measured, and then compared with the low-voltage measurement module V1-V. n The measured voltage and the output voltage of the reference voltage source 4 are used to measure the low-voltage measurement module V1-V. nCalibrate to improve the accuracy of the voltage measurement circuit in measuring battery voltage.

[0071] For example, the control module can connect the series circuit of the low-voltage measurement module V1 and the reference voltage source 4 by turning on A0 and A1; the control module can also connect the series circuit of the low-voltage measurement module V2 and the reference voltage source 4 by turning on A2 and A3. Similarly, the control module can connect the series circuit of the second switching unit A0-A1 by simultaneously turning on A0-A1. 2n-1 To simultaneously connect the low-voltage measurement modules V1-V n The series circuit with reference voltage source 4, and then the low voltage measurement module V1-V n The voltage across the reference voltage source 4 can be measured simultaneously, meaning that each low-voltage measurement module can measure the voltage across the reference voltage source 4 in parallel.

[0072] In the above embodiments, another circuit structure for the second switching circuit is provided, which eliminates the need for... Figure 1 In the corresponding implementation, it is necessary to connect A0 and A... n+1 At that time, conduction is performed sequentially except for A. 1- A n All the second switching units outside are connected in sequence to the low-voltage measurement modules V1-V n In this embodiment, the low-voltage measurement module V1-V is connected in series with the reference voltage source. n It can simultaneously measure the voltage across the reference voltage source, thereby reducing the time required to obtain the error values ​​corresponding to each low-voltage measurement module.

[0073] In some embodiments, a specific control method for the control module is provided. The control module is used to control each switching unit in the second switching circuit 3, so that each low-voltage measurement module V1-V n With all connections to the reference voltage source 4 disconnected, the switching units in the first switching circuit 2 are controlled, and the control is achieved through the low-voltage measurement modules V1-V1. n The corresponding cell C1-C was measured. n Voltages U1, U2, ..., U n The control module is also used to control each switching unit in the first switching circuit 2, so that each low-voltage measurement module V1-V n With each cell C1-C n With all connections disconnected, control is applied to each switching unit in the second switching circuit 3, and this is done via each low-voltage measurement module V1-V1. n The voltages V1, V2, ..., V output from reference voltage source 4 were measured. n The control module is also used to calculate V1, V2, ..., V respectively. n The difference between the voltage and the preset reference voltage is used to obtain the voltage values ​​of each low-voltage measurement module V1-V.n Error σ v1 , σ v2 , ..., σ vn And according to σ v1 , σ v2 , ..., σ vn For U1, U2,...,U n After calibration, we obtain U1', U2', ..., U n Then add up U1', U2', ..., U n 'The obtained U sum The voltage output of battery 1 is measured.

[0074] by Figure 1 Taking the circuit as an example, the control module will disconnect A0-A n+1 And S0-S is connected n At that time, record the low-voltage measurement module V1-V n The measured values ​​U1, U2, ..., U n The control module will also disconnect S0-S n And A0 and A are connected n+1 At that time, conduction is performed sequentially except for A. 1- A n All second switching units outside the low-voltage measurement module V1-V are used to record the low-voltage measurement module V1-V. n The measured values ​​V1, V2, ..., V at both ends of reference voltage source 4 are measured respectively. n Then calculate V1, V2, ..., V respectively. n The difference between the voltage and the preset reference voltage is used to obtain the voltage values ​​of each low-voltage measurement module V1-V. n Error σ v1 , σ v2 , ..., σ vn And according to σ v1 , σ v2 , ..., σ vn For U1, U2,...,U n After calibration, we obtain U1', U2', ..., U n Then add up U1', U2', ..., U n 'The obtained U sum The voltage output of battery 1 is measured.

[0075] The following explanation uses the calibration of U1 as an example. When the control module turns on S0 and S1, the series circuit between the low-voltage measurement module V1 and the battery cell C1 is connected, and the voltage U1 measured by the low-voltage measurement module V1 in the battery cell C1 is recorded as 5V. When the control module turns on all the second switching units except A1, the series circuit between the low-voltage measurement module V1 and the reference voltage source 4 is connected, and the voltage V1 measured by the low-voltage measurement module V1 in the reference voltage source 4 is recorded as 3V. If the preset reference voltage of the reference voltage source 4 is 2.8V, then the error σ of the low-voltage measurement module V1 is... v1 =3-2.8=0.2V, so the measured value of the low-voltage measurement module V1 can be considered to be 0.2V larger than the actual value. Therefore, σ can be used... v1 The U1 measured by the low-voltage measurement module V1 is calibrated, for example, U1' = U1 - σ v1 =5 - 0.2 = 4.8V.

[0076] In the above embodiments, a specific control method for the control module is provided, and the measurement error σ of the low-voltage measurement module can be obtained relatively accurately. v1 , σ v2 , ..., σ vn Furthermore, calibration is used to compensate for the accuracy degradation of the low-voltage measurement module, thereby ensuring the accuracy of the low-voltage measurement module throughout its entire lifecycle.

[0077] In some embodiments, please refer to Figure 3 The voltage measurement circuit also includes a high voltage measurement module 5, with its two ends connected to the two ends of the battery 1, and the control module also connected to the high voltage measurement module 5.

[0078] In some embodiments, one end of the high-voltage measurement module 5 can be connected to one end of the battery 1 via at least one switching unit, and the other end of the battery 1 can be connected to the other end of the high-voltage measurement module 5; alternatively, both ends of the high-voltage measurement module 5 can each be connected to both ends of the battery 1 via at least one switching unit. A control module is connected to the switching unit and is used to control the switching unit to be turned on or off. When the control module controls the switching unit to be turned on, the measurement circuit between the high-voltage measurement module 5 and the battery 1 is connected, so that the high-voltage measurement module 5 can measure the voltage across the battery 1.

[0079] In some embodiments, the two ends of the high-voltage measurement module 5 can each be connected to the two ends of the battery 1 via a switching unit. The control module is also connected to these two switching units to control the switching units to be turned on or off. When the control module controls these two switching units to be turned on simultaneously, the measurement circuit between the high-voltage measurement module 5 and the battery 1 is connected, so that the voltage across the battery 1 can be measured by the high-voltage measurement module 5.

[0080] High voltage measurement module 5 is used to measure the voltage output by battery 1 to obtain V. totalThe control module is specifically used in |V total -U sum When the error exceeds the allowable error of high-voltage measurement module 5, U sum The voltage output of battery 1 is measured.

[0081] The high-voltage measurement module 5 can be a large-range voltage sensor, such as a large-range voltmeter.

[0082] Because the low-voltage measurement module has a small measurement range and high measurement accuracy, for example, the measurement accuracy of the low-voltage measurement module is 0.01V, when the change in the measured value of the low-voltage measurement module is greater than 0.01V, it will change the measured value recorded by the low-voltage measurement module. This may cause the measured value of the voltage of battery 1 output by the voltage measurement circuit to fluctuate continuously, and the output measured value is not stable enough.

[0083] In this embodiment, a high-voltage measurement module 5 with lower measurement accuracy is used to directly measure the voltage V across the battery 1. total Then obtain the U obtained by measuring and calculating through the low-voltage measurement module. sum Compare the voltage measured by high voltage measurement module 5 with U sum If the absolute value of the difference between the two is too large, specifically exceeding the allowable error of the high-voltage measurement module 5, then it is considered that the measurement accuracy of the high-voltage measurement module 5 is difficult to achieve the measurement accuracy of the battery 1 voltage, and it is necessary to adjust the measurement accuracy according to U. sum The measured values ​​of high-voltage measurement module 5 are calibrated, specifically by adjusting the U... sum The measured value is used as the measurement value of the high voltage measurement module 5.

[0084] In the above embodiments, to avoid the voltage measurement circuit continuously changing the battery measurement value due to the excessively high accuracy of the low-voltage measurement module, the measurement circuit also includes a lower-accuracy high-voltage measurement module to directly measure the battery output voltage. Furthermore, the voltage V measured by the high-voltage measurement module is the only accurate value. total with U sum The U measured by the low-voltage measurement module is only used when the absolute value of the difference is greater than the allowable error of the high-voltage measurement module. sum The measured battery output voltage is used as the basis for determining the test error |V of the high-voltage measurement module. The above embodiment can accurately determine this error. total -U sum Furthermore, high-precision high-voltage measurement values ​​can be obtained through calibration. These high-precision high-voltage measurement values ​​are beneficial for more accurate high-voltage fault diagnosis, relay diagnosis, charge and discharge management, and battery safety early warning.

[0085] In some embodiments, U1, U2, ..., U n One specific implementation method for calibration. The control module is also specifically used for |σvN |>σ allow , and σ vN When ≥0, according to formula U N '=U N -|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |>σ allow , and σ vN When <0, according to formula U N '=U N +|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |≤σ allow At that time, U N '=U N To obtain U1', U2', ..., U n '; where σ allow The allowable error for each low-voltage measurement module is set; N is any integer from 1 to n.

[0086] The control module can respond when the measurement error of the low-voltage measurement module is too large, specifically in |σ vN |>σ allow At that time, for U1, U2, ..., U n Calibration is performed in two cases: one is when σ vN When the value is ≥0, the measured value of the low-voltage measurement module is considered too large compared to the actual value. In this case, the difference between the measured value and the actual value is subtracted, i.e., the difference is calculated using U. N '=U N -|σ vN |To calibrate U1, U2, ..., U n Another is when σ vN When the value is less than 0, the measured value of the low-voltage measurement module is considered too small compared to the actual value. In this case, the difference between the measured value and the actual value is increased, i.e., by increasing U... N '=U N +|σ vN |To calibrate U1, U2, ..., U n To obtain U1', U2', ..., U n '.

[0087] When the measurement error of the low-voltage measurement module is within the allowable range, specifically in |σ vN |≤σ allow At that time, the control module directly commands U N '=U N To obtain U1', U2', ..., U n ', which is equivalent to not having any pairs of U1, U2, ..., Un Perform calibration.

[0088] The following explanation uses the calibration of U1 as an example. If σ v1 =0.2V, σ allow =0.1V, at this time σ v1 >σ allow U1 needs to be calibrated because σ v1 =0.2V>0, then U1'=U1-σ v1 =U1-0.2V.

[0089] In some embodiments, σ allow The first permissible error is the smaller of the first and second permissible errors, where the first permissible error is the maximum permissible error of each low-voltage measurement module, and the second permissible error is |σ|. vtotal | / n,|σ vtotal | represents the maximum permissible error of the high-voltage measurement module.

[0090] In the above embodiments, the allowable error σ for the low-voltage measurement module is set. allow Specifically, it is the smaller of the maximum permissible error of the low-voltage measurement module and the second permissible error allocated to each low-voltage measurement module from the maximum permissible error of the high-voltage measurement module. Thus, when the error satisfies σ... allow At that time, it will definitely be able to meet the error requirements of both the low-voltage measurement module and the high-voltage measurement module.

[0091] In some embodiments, the control module can also be connected to the reference voltage source 4, and the control module can also set a preset reference voltage V. REF = (V1+V2+…+V n ) / n.

[0092] In other embodiments, technicians can also adjust the preset reference voltage V according to actual needs. REF Configure the settings.

[0093] In the above embodiments, preset reference voltages are set as V1, V2, ..., V n The average value can make the preset reference voltage close to the voltage range of each cell, reducing the adjustment range of each low-voltage measuring device and the time spent on adjustment.

[0094] This application provides a voltage measurement method. For the control module in the voltage measurement circuit of any of the above embodiments, the components included in the voltage measurement circuit and the connection relationship between each module, please refer to the embodiment corresponding to the voltage measurement circuit described above.

[0095] The voltage measurement method includes: controlling the switching units in the first and second switching circuits to be turned on or off, and acquiring the voltage of each cell by each low-voltage measurement module.

[0096] In some embodiments, controlling the switching units in the first and second switching circuits to be turned on or off, and obtaining the voltage of each cell measured by each low-voltage measurement module, includes: controlling each switching unit in the second switching circuit so that each low-voltage measurement module is disconnected from the reference voltage source, controlling each switching unit in the first switching circuit, and obtaining the voltage U1, U2, ..., U of the corresponding cell through each low-voltage measurement module. n The method further includes: controlling each switching unit in the first switching circuit so that each low-voltage measurement module is disconnected from each battery cell, then controlling each switching unit in the second switching circuit, and measuring the voltages V1, V2, ..., V output from the reference voltage source through each low-voltage measurement module. n Calculate V1, V2, ..., V respectively. n The error σ of each low-voltage measurement module is obtained by measuring the difference between the voltage and the preset reference voltage output from the reference voltage source. v1 , σ v2 , ..., σ vn According to σ v1 , σ v2 , ..., σ vn For U1, U2,...,U n After calibration, we obtain U1', U2', ..., U n '; will accumulate U1', U2', ..., U n 'The obtained U sum , which is the measured voltage output of the battery.

[0097] In some embodiments, the voltage measurement circuit further includes a high-voltage measurement module, the two ends of which are connected to the two ends of the battery. A control module is also connected to the high-voltage measurement module. The high-voltage measurement module is used to measure the voltage output by the battery to obtain V. total The sum of U1', U2', ..., U will be accumulated. n 'The obtained U sum The measured battery output voltage includes: in |V total -U sum When the error exceeds the allowable error of the high-voltage measurement module, U sum The measured voltage output of the battery.

[0098] In some embodiments, in |σ vN |>σ allow , and σ vN When ≥0, according to formula UN '=U N -|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |>σ allow , and σ vN When <0, according to formula U N '=U N +|σ vN |Calibrate U1, U2, ..., U n ; in |σ vN |≤σ allow At that time, U N '=U N To obtain U1', U2', ..., U n '; where σ allow The allowable error for each low-voltage measurement module is set; N is any integer from 1 to n.

[0099] In some embodiments, σ allow The first permissible error is the smaller of the first and second permissible errors, where the first permissible error is the maximum permissible error of each low-voltage measurement module, and the second permissible error is |σ|. vtotal | / n,|σ vtotal | represents the maximum permissible error of the high-voltage measurement module.

[0100] In some embodiments, the control module is also connected to a reference voltage source, and the control module is further configured to set a preset reference voltage V. REF = (V1+V2+…+V n ) / n.

[0101] In some embodiments, based on Figure 3 Please refer to the circuit diagram. Figure 4 A flowchart illustrating the voltage measurement method.

[0102] Step 101, close S0, S1, S2, ..., S n-2 S n-1 S n Disconnect A0, A1, A2, ..., A n-1 A n A n+1 Measure the cells C1, C2, ..., U n-1 C n Voltages U1, U2, ... U n-1 U n .

[0103] Step 102: Set the preset reference voltage V of the reference voltage source. REF Let U1, U2, ... U n-1 Un The average value, i.e., V REF = (U1+U2+…+U n-1 +U n ) / n.

[0104] Step 103, disconnect S0, S1, S2, ..., S n-2 S n-1 S n Close A0, A1, ..., A x-1 A x+1 A n A n+1 , using A x Measure the preset reference voltage and record it as V. REFAx .

[0105] Where A0, A1, ..., A are closed x -1, A x+1 A n A n+1 That is, closing the block except A x All switches with A number except those listed above; x ranges from 1 to n, and V can be measured. REFA1 V REFA2 , ..., V REFAn-1 V REFAn .

[0106] Step 104, calculate V REFAx -V REF To obtain the low-voltage measurement modules V1, V2, ..., V n-1 V n absolute error σ v1 , σ v2 , ..., σ vn .

[0107] Where, σ v1 , σ v2 , ..., σ vn It can be positive, negative, or 0.

[0108] Step 105, the measured value V of the high voltage measurement module total The maximum permissible error is set to the absolute value |σ vtotal |, Low-voltage measuring equipment V1, V2, ..., V n-1 V n The maximum permissible error is set to the absolute value |σ v |, for |σ vtotal | / n and |σ v |Take the smaller value, denoted as σ allow .

[0109] Step 106, determine |σvn Is it greater than σ? allow If yes, proceed to step 107; otherwise, proceed to step 108.

[0110] Step 107, determine σ vn If the value is greater than or equal to 0, proceed to step 109; otherwise, proceed to step 110.

[0111] Step 108, Low-voltage measurement module V n The measured value is based on the actual measured value U. n Output, σ vn No update, i.e., U n '=U n , σ vn '=σ vn .

[0112] Step 109, connect the low-voltage measurement module V n The measured value U n Corrected to U n '=U n -|σ vn |,σ vn '=-σ allow .

[0113] Step 110, connect the low-voltage measurement module V n The measured value U n Corrected to U n '=U n +|σ vn |,σ vn '=σ allow .

[0114] Step 111, accumulate U1', U2', ..., U n 'Get U sum , cumulative σ v1 ',σ v2 ',...,σ vn 'Get U sum Error value σ n .

[0115] Step 112, determine |V total -U sum Is it greater than the allowable error σ of the high-voltage measurement module? vtotal If yes, proceed to step 113; otherwise, proceed to step 114.

[0116] Step 113, V total Corrected to U sum ,|V total -U sum |Updated to σ nOutput, i.e., V total '=U sum ,|V total -U sum |'=σ n .

[0117] Step 114, according to the actual measured value V of the high voltage measurement module total Output, |V total -U sum |Unchanged, i.e., V total '=V total ,|V total -U sum |'=|V total -U sum |

[0118] This application provides a circuit board including the voltage measurement circuit described in the above embodiments.

[0119] This application provides a control module; please refer to the following embodiments. Figure 5 The device includes: at least one processor 201; and a memory 202 communicatively connected to at least one processor 201; wherein the memory 202 stores instructions executable by at least one processor 201, the instructions being executed by at least one processor 201 to enable at least one processor 201 to perform the voltage measurement method described above.

[0120] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0121] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A voltage measuring circuit for measuring the output voltage of a battery, said battery comprising n cells connected in series, wherein, n is an integer greater than 1; The circuit includes: n low-voltage measurement modules corresponding one-to-one with the n battery cells, a first switching circuit, a second switching circuit, a reference voltage source, and a control module, wherein the reference voltage source is used to output a preset reference voltage; the second switching circuit includes 2n second switching units; both ends of the n low-voltage measurement modules are connected to the two ends of the reference voltage source through the second switching units; Each of the low-voltage measurement modules is connected to the corresponding two ends of the battery cell via the first switching circuit. Each of the low-voltage measurement modules is also connected to the two ends of the reference voltage source via the second switching circuit. The control module is connected to the switching unit in the first switching circuit and the second switching circuit. The control module is also connected to each of the low-voltage measurement modules. The control module is used to control the switching unit to be turned on or off, and to obtain the voltage of each cell measured by each low-voltage measurement module.

2. The voltage measurement circuit according to claim 1, wherein, The first switching circuit includes n+1 first switching units; The n-1 connection nodes formed by the n low-voltage measurement modules connected in series and the two ends of the branch formed by the n low-voltage measurement modules connected in series are used as first connectable nodes. The n-1 connection nodes formed by the n battery cells connected in series and the two ends of the branch formed by the n battery cells connected in series are used as second connectable nodes. Each first connectable node is connected to the corresponding second connectable node through the first switch unit.

3. The voltage measurement circuit according to claim 2, wherein, The second switching circuit includes n+2 second switching units; The n-1 connection nodes formed by the series connection of n second switch units and the two ends of the branch formed by the series connection of n second switch units are used as third connectable nodes. Each first connectable node is connected to the corresponding third connectable node through the second switch unit. The two ends of the branch formed by the series connection of the second switch units are also connected to the two ends of the reference voltage source through the second switch unit.

4. The voltage measurement circuit according to claim 1, wherein, The control module is specifically used to control each switching unit in the second switching circuit, so that when each low-voltage measurement module is disconnected from the reference voltage source, it controls each switching unit in the first switching circuit and measures the voltage of the corresponding battery cell through each low-voltage measurement module. , , ..., ; The control module is also used to control each switching unit in the first switching circuit, so that when each low-voltage measurement module is disconnected from each battery cell, it controls each switching unit in the second switching circuit and measures the voltage output of the reference voltage source through each low-voltage measurement module. , , ..., ; The control module is also used to calculate separately. , , ..., The error of each low-voltage measurement module is obtained by measuring the difference between the voltage and the preset reference voltage. , , ..., and according to , , ..., right , , ..., Perform calibration to obtain ', ',…, ', then accumulate ', ',…, 'Received The measured voltage output of the battery is _____.

5. The voltage measurement circuit according to claim 4, wherein, The voltage measurement circuit also includes a high-voltage measurement module, the two ends of which are connected to the two ends of the battery, and the control module is also connected to the high-voltage measurement module; The high-voltage measurement module is used to measure the voltage output by the battery. ; The control module is specifically used for... When the error exceeds the allowable error of the high-voltage measurement module, The voltage output by the battery is measured.

6. The voltage measurement circuit according to claim 5, wherein, The control module is also specifically used for... ,and At that time, according to the formula calibration , , ..., ;exist ,and At that time, according to the formula calibration , , ..., ;exist hour, In order to obtain ', ',…, '; in, The allowable error for each of the low-voltage measurement modules is defined; N is any integer from 1 to n.

7. The voltage measurement circuit according to claim 6, wherein, The The smaller of the first allowable error and the second allowable error, wherein the first allowable error is the maximum allowable error of each of the low-voltage measurement modules, and the second allowable error is... , This represents the maximum permissible error of the high-voltage measurement module.

8. The voltage measurement circuit according to any one of claims 4 to 7, wherein, The control module is also connected to the reference voltage source, and the control module is also used to set the preset reference voltage. .

9. A voltage measurement method, based on a control module in a voltage measurement circuit as described in any one of claims 1 to 3, the method comprising: The system controls the switching units in the first and second switching circuits to turn on or off, and obtains the voltage of each cell measured by each low-voltage measurement module.

10. The voltage measurement method according to claim 9, wherein, Controlling the switching units in the first and second switching circuits to turn on or off, and acquiring the voltage of each cell measured by each low-voltage measurement module, including: Controlling each switching unit in the second switching circuit to disconnect all low-voltage measurement modules from the reference voltage source, while controlling each switching unit in the first switching circuit, and measuring the voltage of the corresponding battery cell through each low-voltage measurement module. , , ..., ; The method further includes: The switching units in the first switching circuit are controlled so that each low-voltage measurement module is disconnected from each battery cell. Then, the switching units in the second switching circuit are controlled, and the voltage output of the reference voltage source is measured by each low-voltage measurement module. , , ..., ; Calculate separately , , ..., The error of each low-voltage measurement module is obtained by measuring the difference between the voltage and the preset reference voltage output by the reference voltage source. , , ..., ; according to , , ..., right , , ..., Perform calibration to obtain ', ',…, '; Accumulation ', ',…, 'Received , which is the measured voltage output of the battery.

11. The voltage measurement method according to claim 10, wherein, The voltage measurement circuit further includes a high-voltage measurement module, the two ends of which are connected to the two ends of the battery. The control module is also connected to the high-voltage measurement module. The high-voltage measurement module is used to measure the voltage output by the battery. ; The accumulation ', ',…, 'Received The measured voltage output of the battery includes: exist When the error exceeds the allowable error of the high-voltage measurement module, The voltage output by the battery is measured.

12. The voltage measurement method according to claim 11, wherein, According to , , ..., right , , ..., Perform calibration to obtain ', ',…, ',include: exist ,and At that time, according to the formula calibration , , ..., ; exist ,and At that time, according to the formula calibration , , ..., ; exist hour, In order to obtain ', ',…, '; in, The allowable error for each of the low-voltage measurement modules is defined; N is any integer from 1 to n.

13. The voltage measurement method according to claim 12, wherein, The The smaller of the first allowable error and the second allowable error, wherein the first allowable error is the maximum allowable error of each of the low-voltage measurement modules, and the second allowable error is... , This represents the maximum permissible error of the high-voltage measurement module.

14. The voltage measurement method according to any one of claims 10 to 13, wherein, The control module is also connected to the reference voltage source, and the control module is also used to set the preset reference voltage. .

15. A circuit board comprising a voltage measurement circuit as described in any one of claims 1 to 8.

16. A control module, comprising: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the voltage measurement method as described in any one of claims 9 to 14.

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