CN108663622B - Battery pack voltage measuring circuit and voltage measuring system - Google Patents
Battery pack voltage measuring circuit and voltage measuring system Download PDFInfo
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- CN108663622B CN108663622B CN201710204251.5A CN201710204251A CN108663622B CN 108663622 B CN108663622 B CN 108663622B CN 201710204251 A CN201710204251 A CN 201710204251A CN 108663622 B CN108663622 B CN 108663622B
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
Abstract
The application provides a group battery voltage measurement circuit and voltage measurement system, wherein, including voltage sampling network, voltage processing sub-circuit and the controller of series connection in proper order in the group battery voltage measurement circuit. The voltage sampling network is used for collecting voltage values of all the battery cells in the battery pack to the ground; the voltage processing sub-circuit is used for performing analog operation on the voltage values of the battery cells acquired by the voltage sampling network so as to determine sampling voltages at two ends of each battery cell; and the controller is used for determining the actual voltage of each battery cell according to the sampling voltage of each battery cell and the resistance value of the voltage sampling network. Therefore, the voltage of each battery cell is sampled and calculated through the analog circuit, the precision of the sampled voltage is improved, errors caused in the operation process are avoided, conditions are provided for realizing accurate control of each battery cell in the battery, and the reliability and safety of the battery are improved.
Description
Technical Field
The application relates to the technical field of electronics, especially, relate to a group battery voltage measurement circuit and voltage measurement system.
Background
With the development of new energy technology, batteries are more widely used. At present, in many fields, because one single battery is difficult to meet the use requirement of a system, a plurality of batteries are generally used in series.
However, when multiple batteries are used in series, if the voltages of the single battery cells are inconsistent, the batteries are damaged. Therefore, when multiple batteries are used in series, the voltage condition of each cell in the series battery pack needs to be monitored to ensure that the series battery pack works normally.
Fig. 1 is a circuit diagram of a current cell voltage measurement circuit. As shown in fig. 1, the voltage of each cell is measured by using resistance voltage division. However, when the number of batteries connected in series is large, the voltage of some voltage dividing resistors is large, which makes the accuracy and precision of the finally determined cell voltage poor, and is not favorable for the control of the battery system.
Disclosure of Invention
The present application is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, a first objective of the present application is to provide a battery pack voltage measurement circuit, which implements sampling and calculation of voltages of each battery cell through an analog circuit, improves precision of sampled voltages, avoids errors caused in an operation process, provides conditions for implementing accurate control of each battery cell in a battery, and improves reliability and safety of the battery.
A second object of the present application is to provide a battery pack voltage measurement system.
To achieve the above object, a first aspect of the embodiments of the present application provides a battery pack voltage measurement circuit, including: the voltage sampling network, the voltage processing sub-circuit and the controller are sequentially connected in series;
the voltage sampling network is used for collecting voltage values of all the battery cores in the battery to the ground;
the voltage processing sub-circuit is used for performing analog operation on the voltage values of the battery cells acquired by the voltage sampling network so as to determine sampling voltages at two ends of each battery cell;
and the controller is used for determining the actual voltage of each battery cell according to the sampling voltage of each battery cell and the resistance value of the voltage sampling network.
The battery pack voltage measuring circuit provided by the embodiment of the application comprises a voltage sampling network, a voltage processing sub-circuit and a controller which are sequentially connected in series, wherein the voltage sampling network is used for collecting voltage values of all battery cores in a battery to the ground; the voltage processing sub-circuit is used for performing analog operation on the voltage values of the battery cells acquired by the voltage sampling network so as to determine sampling voltages at two ends of each battery cell; and the controller is used for determining the actual voltage of each battery cell according to the sampling voltage of each battery cell and the resistance value of the voltage sampling network. Therefore, the voltage of each battery cell is sampled and calculated through the analog circuit, the precision of the sampled voltage is improved, errors caused in the operation process are avoided, conditions are provided for realizing accurate control of each battery cell in the battery, and the reliability and safety of the battery are improved.
To achieve the above object, a second aspect of the embodiments of the present application provides a voltage measurement system, including: the battery pack voltage measurement circuit as described in the above embodiments.
The voltage measurement system that this application embodiment provided, after carrying out the mining pressure to each electric core through resistance sampling network, carry out analog operation by analog circuit to sampling voltage to confirm the sampling voltage at each electric core both ends, and then by the controller according to the voltage division ratio of analog sampling voltage and sampling resistance bridge, confirm the actual voltage value at each electric core both ends. Therefore, the voltage of each battery cell is sampled and calculated through the analog circuit, the precision of the sampled voltage is improved, errors caused in the operation process are avoided, conditions are provided for realizing accurate control of each battery cell in the battery, and the reliability and safety of the battery are improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a current cell voltage measurement circuit diagram;
FIG. 2 is a schematic diagram of a battery pack voltage measurement circuit according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a portion of a voltage processing sub-circuit according to an embodiment of the present disclosure;
FIG. 4 is a schematic diagram of a battery pack voltage measurement circuit according to another embodiment of the present application;
fig. 5 is a schematic structural diagram of a battery voltage measurement circuit according to another embodiment of the present application;
fig. 6 is a schematic structural diagram of a battery pack voltage measurement circuit according to yet another embodiment of the present application.
Detailed Description
Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.
The battery pack voltage measurement circuit and the voltage measurement system according to the embodiments of the present application are described below with reference to the drawings.
Fig. 2 is a schematic diagram of a battery voltage measurement circuit according to an embodiment of the present application.
As shown in fig. 2, the battery pack voltage measuring circuit includes: the voltage sampling network 1, the voltage processing sub-circuit 2 and the controller 3 are sequentially connected in series;
the voltage sampling network 1 is used for collecting voltage values of all the battery cores in the battery 4 to the ground;
the voltage processing sub-circuit 2 is configured to perform analog operation on the voltage values of the battery cells acquired by the voltage sampling network 1 to determine sampling voltages at two ends of each battery cell;
and the controller 3 is configured to determine the actual voltage of each battery cell according to the sampling voltage of each battery cell and the resistance value of the voltage sampling network.
Specifically, this application mainly provides a voltage measurement circuit to among the prior art, when utilizing voltage sampling network to measure the voltage of every electric core in a plurality of batteries of establishing ties, when voltage on the divider resistance is great, the sampling precision falls and the degree of accuracy reduces, is unfavorable for the problem of battery system's control. Firstly, a voltage sampling network is utilized to respectively collect the voltage of each battery cell, then a voltage processing sub-circuit is utilized to carry out analog operation processing on the collected voltage so as to determine the sampling voltage at two ends of each battery cell, and then a controller determines the actual voltage value at two ends of each battery cell according to the resistance value of the voltage sampling network. In the embodiment of the application, after the voltage of each electric core is sampled, the sampled voltage is subjected to operation processing through the analog circuit, so that the measurement precision is improved.
The voltage sampling network 1 may be formed as shown in fig. 1, or may also be formed as shown in fig. 2, and is formed by N sampling resistor bridges, where one ends of the N sampling resistor bridges are respectively connected to ground, the other ends of the N sampling resistor bridges are respectively connected to anodes of N electrical cores, N is a positive integer greater than 1, and the sampling resistor bridges all output voltage values to ground, so that accuracy and reliability of the voltage values output by the sampling resistor bridges are ensured.
Correspondingly, the voltage processing sub-circuit 2 includes N voltage processing units, and input ends of the N voltage processing units are respectively connected to output ends of the N sampling resistance bridges, and are configured to perform analog operation processing on voltage values output by the N resistance bridges, so as to respectively determine sampling voltages at two ends of each electrical core;
and the controller 3 is respectively connected with the output ends of the N voltage processing units, and is configured to determine the actual voltages at the two ends of each electrical core according to the sampling voltages at the two ends of each electrical core and the voltage division ratio of each sampling resistor bridge.
In the specific implementation, the resistance values of the resistors in the resistor bridge may be selected according to the voltage level of the electric core to be measured and the power level of the resistors, which is not limited in the embodiment of the present application.
In addition, each resistance bridge comprises an upper bridge arm and a lower bridge arm; and the intersection point of the upper bridge arm and the lower bridge arm is connected with the voltage processing sub-circuit, wherein the voltage division ratio of the upper bridge arm and the small bridge arm in the resistance bridge can be set as required. For example, the resistance value of the upper bridge arm is greater than that of the lower bridge arm, that is, the partial pressure of the resistance bridge is greater; or the resistance value of the upper bridge arm is smaller than that of the lower bridge arm, namely the partial pressure of the resistance bridge is smaller; or, the resistance value of the upper arm is equal to the resistance value of the lower arm, that is, the resistance bridge performs an equal proportion voltage division, and the like, which is not limited in this embodiment.
In a preferred implementation form of the present application, each of the resistance bridges may be implemented by dividing voltage in equal proportion. Because, when the voltage division ratio of the resistance bridge is too large, the sampling accuracy is lowered; when the voltage division ratio is too small, the obtained sampling voltage value is high, the sampling voltage value is not suitable for direct processing of a post-stage circuit, and the sampling voltage needs to be preprocessed and then input into the post-stage circuit. Therefore, the resistance value of the upper bridge arm of each resistance bridge is equal to that of the lower bridge arm in the embodiment, so that the sampling precision is ensured, and the processing complexity of a post-stage processing circuit is reduced.
It should be noted that the upper bridge arm and the lower bridge arm in each resistance bridge may respectively include one or more resistors, and it is only necessary that the resistance value of the upper bridge arm is equal to the resistance value of the lower bridge arm.
As can be seen from fig. 2, the sampling voltages output by the output ends of the resistor bridges in the voltage sampling network are not all voltages of each electrical core, and to obtain voltages on each electrical core, it is further necessary to perform differential operation processing on each sampling voltage, and if the voltages at the two ends of the electrical core are directly subjected to differential operation, the precision is reduced, and the measurement error is increased, so in this embodiment of the application, the voltages sampled at the two ends of each electrical core are processed by the voltage processing sub-circuit shown in fig. 3, so as to determine the sampling voltage of each electrical core.
Fig. 3 is a schematic structural diagram of a part of a voltage processing sub-circuit according to an embodiment of the present disclosure.
The mth voltage processing unit 2m in the voltage processing sub-circuit shown in fig. 3 includes: the resistor comprises a first resistor 2m1, a second resistor 2m2, a first operational amplifier 2m3, a switch tube 2m4 and a third resistor 2m5, wherein m is a positive integer which is greater than 1 and less than N;
one end of the first resistor 2m1 is connected with the output end of the (m-1) th resistor bridge, and the other end of the first resistor 2m1 is connected with the positive input end of the first operational amplifier 2m 3;
one end of the second resistor 2m2 is connected with the output end of the mth resistor bridge, and the other end of the second resistor 2m2 is connected with the negative input end of the first operational amplifier 2m3 and one end of the switch tube 2m 4;
the output end of the first operational amplifier 2m3 is connected with the control end of the switch tube 2m 4;
the other end of the switch tube 2m4 is connected with one end of the third resistor 2m 5;
the other end of the third resistor 2m5 is connected to ground GND.
It can be understood that, in the voltage sampling network provided in this embodiment of the present application, the voltage output by the first resistance bridge is the voltage at both ends of the first battery cell, that is, the voltage at both ends of the first battery cell can be determined without performing differential processing on the output value of the first resistance bridge, and therefore, in this embodiment of the present application, only the sampling voltages output by the second resistance bridge and the following bridges may be processed by the processing circuit shown in fig. 3.
For more clearly explaining the battery pack voltage measuring circuit provided in the present application, referring to fig. 4, taking N as 4 and the resistor bridge including two resistors with equal resistance as an example, the structure of the battery pack voltage measuring circuit is further explained.
Fig. 4 is a schematic structural diagram of a battery pack voltage measurement circuit according to another embodiment of the present application.
As shown in fig. 4, the resistor R1 and the resistor R5 are connected in parallel with the cell B1, and are configured to sample a voltage across the cell B1, where the sampling voltage is V1; the resistor R2 and the resistor R6 are connected with the battery cells B2 and B1 in parallel to sample the voltage on the battery cell B2, and the sampled voltage is V2; for the same reason, the sampled voltages V3 and V4 can be obtained, respectively.
As for the sampling voltage V1, since it directly reflects the voltage across the cell B1, the actual voltage of the cell B1 can be directly determined according to the values of V1 and the resistors R1 and R5.
However, the sampling voltages V2, V3, and V4 are voltages of the cells B2, B3, and B4 to the ground, respectively, and therefore, it is necessary to perform difference processing on the sampling voltages V1, V2, V3, and V4, respectively, to finally determine the voltage values of the cells B2, B3, and B4, and in order to reduce errors caused in the processing process and ensure the sampling accuracy as much as possible, in this embodiment of the application, as shown in fig. 3, an analog voltage processing sub-circuit is used to perform difference processing on the sampling voltages V1, V2, V3, and V4.
As shown in fig. 4, the resistor R9 in the 2 nd voltage processing unit is connected to the output terminal of the first resistor bridge and the positive input terminal of the operational amplifier a1, the resistor R10 is connected to the output terminal of the second resistor bridge and the negative input terminal of the operational amplifier a1, the output terminal of the operational amplifier is connected to the control terminal of the switching tube G1, one end of the switching tube G1 is connected to one end of the resistor R11, and the other end of the switching tube G1 is connected to the negative input terminal of the operational amplifier: the structures of the 3 rd voltage processing unit and the 4 th voltage processing unit are the same as those of the 2 nd voltage processing unit.
The two resistors respectively connected to the positive input terminal and the negative input terminal of the operational amplifier in the voltage processing unit may have the same or different resistance values, which is not limited in the embodiments of the present application.
It is understood that, in order to reduce the complexity of the circuit, the first resistor 2m1 and the second resistor 2m2 in the mth voltage processing unit may be resistors with the same resistance, so as to reduce the device types and reduce the complexity of the type selection.
In addition, the switching device in the voltage processing unit may be a P-channel Metal Oxide Semiconductor field effect transistor (PMOS).
The following description will be made of the operation principle of the voltage processing unit, taking the 2 nd voltage processing unit as an example.
As shown in fig. 4, in the circuit, during operation, the sampling voltages V1 and V2 are connected to the positive and negative input terminals of the operational amplifier through the resistor R9 and the resistor R10, respectively, and after processing by the common-drain amplifying circuit composed of the resistor G1 and the resistor R11, the sampling voltages at the two ends of the cell B2 after operation can be output from the connection terminal of the resistor G1 and the resistor R11.
Specifically, according to the operating principle of the operational amplifier, the voltages at the positive and negative input terminals of the operational amplifier a1 are both V1, so that the current passing through R10 is (V2-V1)/R10, at this time, since V2 > V1, the PMOS type switching tube G1 is turned on, so that the current flows into the ground through G1 and the resistor R11, and therefore the sampled voltage V2 obtained at the resistor R11aComprises the following steps:
the controller then determines V2aThen, the actual voltage value of the battery cell B2 can be determined according to the magnitudes of the resistors R2 and R6.
In bookIn one embodiment, if the resistances of the resistor R2 and the resistor R6 are equal, the voltage V2 is appliedaAnd multiplying by 2 to obtain the actual voltage value of the battery cell B2.
In the same manner, the sampled voltage V3 across resistor R14 can be determinedaComprises the following steps:
the sampling voltage V4 obtained from the resistor R17aComprises the following steps:
and then the actual voltage value of each battery cell can be determined according to the voltage division ratio of each resistor bridge.
In the embodiment of the application, because the analog voltage processing unit is utilized to simulate and differentiate the voltage output by each resistance bridge, the precision and the accuracy of the sampling voltage are improved.
In the voltage processing unit of the present application, the PMOS is used to perform the potential shift, so that the differential amplifier a1 can be powered by a single power supply, thereby simplifying the circuit structure.
Further, for the cell B1, since the voltage output by the resistance bridge is the divided voltage on the cell B1, the output of the resistance bridge corresponding to the cell B1 may not pass through the voltage processing unit, and is directly output to the controller for processing, or the voltage V1 on the cell B1 may be processed only by the operational amplifier.
That is, for fig. 4, the first voltage processing unit in the voltage processing sub-circuit 2 includes a second operational amplifier a 1;
the positive input terminal of the second operational amplifier a1 is connected to the output terminal of the first resistor bridge, and the negative input terminal of the second operational amplifier a1 is connected to the output terminal of the second operational amplifier a 1.
The sampled voltage on the first battery cell B1 is followed by the second operational amplifier a1 and then input to the controller, so that the controller can determine the voltage of the battery cell B1 according to the voltage division ratio of the resistance bridge corresponding to the first battery cell B1.
In addition, it can be understood that the controller may adopt any chip such as an MCU, a single chip microcomputer, an ARM, and a DSP, and the chip processes a digital signal, so that when the chip receives the sampling voltage output by the voltage processing unit, the chip needs to first convert each sampling voltage into a digital signal, and then calculate a digital signal corresponding to the actual voltage of each electrical core according to the digital signal corresponding to the voltage division ratio of each electrical bridge. In the application, the sampling voltage of each battery cell is determined through analog operation, so that the precision loss caused by numerical operation by using a controller is avoided, and the accuracy and precision of the finally determined battery cell voltage are improved.
The embodiment of the application provides a group battery voltage measurement circuit, including the voltage sampling network of series connection in proper order, voltage processing sub-circuit and controller, wherein, including N sampling resistance bridge in the voltage sampling network, the one end of N sampling resistance bridge is connected with ground respectively, the other end of N sampling resistance bridge is connected with the positive pole of N electric core respectively, N voltage processing unit in the voltage processing sub-circuit is connected with the output of N sampling resistance bridge respectively, carry out analog operation to the voltage value of N sampling resistance bridge output and handle, confirm the sampling voltage of N electric core, the controller is according to the sampling voltage of N electric core and the partial pressure ratio of resistance bridge, can confirm the actual voltage value of N electric core. Therefore, the voltage of each battery cell is sampled and calculated through the analog circuit, the precision of the sampled voltage is improved, errors caused in the operation process are avoided, conditions are provided for realizing accurate control of each battery cell in the battery, and the reliability and safety of the battery are improved.
The analysis shows that the voltage sampling and processing mode can improve the sampling precision. If the sampling point is divided into 4 equal parts and the reference voltage of the ADC is reduced to 1/4 as compared with the original Analog to Digital Converter (ADC), which has only 12-bit accuracy, the sampling accuracy of the conventional ADC can be improved by 4 times, and high-accuracy parameter sampling can be realized.
For example, now the accuracy of the ADC is 10 bits and the reference voltage is 3.3V. If the voltage of the measuring cell is 3.3V at maximum, the accuracy of sampling is 3.2mV (3.3V/1024), and if the reference voltage is changed to: when the maximum voltage of the battery is reduced to 0.825V (3.3V/4), the sampling precision is 0.0008mV (0.825V/1024), and compared with the original sampling precision of 3.2mV, the sampling precision of the 12-bit ADC is achieved.
The battery pack voltage measurement circuit provided by the present application is further described below with reference to fig. 5.
Fig. 5 is a schematic structural diagram of a battery pack voltage measurement circuit according to another embodiment of the present application.
As shown in fig. 5, the voltage sampling network 1 includes: n voltage-dividing resistance bridges 12 and LxN sampling resistance bridges 11, wherein L is a positive integer greater than 1;
the voltage processing sub-circuit 2 comprises L multiplied by N voltage processing units 21 and N analog summation circuits 22;
one end of each of the N voltage-dividing resistance bridges 12 is connected to ground, and the other end of each of the N voltage-dividing resistance bridges 12 is connected to the positive electrodes of the N battery cells, wherein each of the voltage-dividing resistance bridges 12 includes L voltage-dividing resistances;
one end of each of the L × N sampling resistance bridges 11 is connected to ground, and the other end of each of the L × N sampling resistance bridges 11 is connected to one end of each of the L × N voltage dividing resistors, which is far away from the ground;
the input ends of the L × N voltage processing units are respectively connected with the output ends of the L × N sampling resistance bridges, and are used for performing analog operation processing on voltage values output by the L × N sampling resistance bridges to respectively determine L initial sampling voltages of the N battery cells;
the input ends of the N analog summing circuits 22 are respectively connected to the output ends of the L voltage processing units 21, and are configured to perform analog summing processing on the L initial sampling voltages, and determine sampling voltages at two ends of each cell respectively.
Specifically, in this embodiment of the application, the voltage sampling network shown in fig. 5 is used to sample voltages at two ends of each electrical core, the voltages at two ends of N electrical cores are divided into L parts respectively through N voltage-dividing resistor bridges 12, and then sampling is performed respectively, so that the sampling accuracy is improved, then the voltage processing sub-circuit 5 is used to perform analog operation on L initial sampling voltages of each electrical core, determine the sampling voltages at two ends of each electrical core, and then the controller determines the actual voltage value of each electrical core according to the sampling voltages at two ends of each electrical core output by the voltage processing sub-circuit.
The resistance values of the resistors in the voltage-dividing resistor bridge can be selected according to the safety and sampling precision of a post-stage circuit, and the embodiment of the application does not limit the resistance values.
In a preferred implementation form of the present application, in order to simplify the complexity of the subsequent voltage processing sub-circuit as much as possible, the voltage dividing resistor bridge may be formed by serially connecting resistors with equal resistance values.
In addition, if the difference between the resistance level of each resistor in the voltage dividing resistor bridge and the resistance level of each resistor in the sampling resistor bridge is large, when each sampling resistor bridge is connected with the voltage dividing resistor and voltage sampling is performed, the magnitude of the sampling voltage is not only related to the voltage dividing ratio of the sampling resistor bridge, but also related to the resistance value of each resistor in the voltage dividing resistor bridge. Therefore, in order to further simplify the calculation process and improve the sampling accuracy, as shown in fig. 5, the voltage sampling network 1 further includes:
(L-1) × N third operational amplifiers 13 for isolating the L × N voltage-dividing resistors from the L × N sampling resistor bridges 11;
and a resistor ki and a resistor k (i +1) in the divider resistance bridge 12 are connected and then connected with the input end of a third operational amplifier ki, the output end of the third operational amplifier ki is connected with the input end of the sampling resistance bridge, wherein ki is a resistor in the divider resistance bridge connected with the kth battery cell in parallel, k is a positive integer greater than or equal to 1, and i is a positive integer greater than or equal to 1 and less than or equal to L.
The battery pack voltage measurement circuit provided by the present application is described in detail below with reference to fig. 6, taking an example in which a battery includes two battery cells.
Fig. 6 is a schematic structural diagram of a battery pack voltage measurement circuit according to yet another embodiment of the present application.
As shown in fig. 6, the battery 4 includes 1 battery cell 41, where L is 4, that is, the voltage-dividing resistor bridge 12 includes 4 voltage-dividing resistors R121, R122, R123, R124, operational amplifiers 131, 132, 131, and 4 resistor bridges 111, 112, 113, and 114, where each resistor bridge is composed of 2 resistors with equal resistance; in the voltage processing sub-circuit 2, 4 voltage processing units 51, 52, 53 and 54 and 1 analog summing circuit 55 are included.
As shown in fig. 6, the voltage processing unit 51 includes only an operational amplifier, and the other voltage processing units 52, 53, and 54 have the same structure and are respectively composed of an operational amplifier, an input resistor, a PMOS, and an output sampling resistor.
If the battery voltage is 4V, the voltage output by the resistor bridge 111 during specific operation is:
the voltage output by the resistor bridge 112 is: 1V, the voltage output by the resistor bridge 113 is:
the voltage output by the resistor bridge 114 is: 2V.
Thus, as can be seen from the explanation of the processing logic of the voltage processing unit according to the above embodiment, the voltage value V output by the voltage processing unit 5151Comprises the following steps:
the voltage value V output by the voltage processing unit 5252Comprises the following steps:
In the same way, the pre-sampling voltage values output by other processing units in the voltage processing sub-circuit can be calculated sequentially. According to the working principle of the voltage processing units, the voltage values output by the voltage processing units are the voltage values at two ends of each resistor in the voltage dividing resistor bridge, namely, the voltages at two ends of each battery cell are divided into 4 values for initial sampling, then the 4 sampling values corresponding to each battery cell are added through the analog summing circuit, the corresponding sampling values of each battery cell can be determined, and then the actual voltage values at two ends of each battery cell can be determined according to the voltage dividing ratio of each sampling resistor bridge by the controller.
Because the voltage of a single battery core is divided into 4 parts for sampling, and the reference voltage is reduced to 1/4, the sampling precision of the conventional ADC can be improved by 4 times, and high-precision parameter sampling is realized. For example, now the accuracy of the ADC is 10 bits and the reference voltage is 3.3V. If the voltage of the measuring cell is 3.3V at the maximum, the sampling accuracy is 3.2mV (3.3V/1024). If the embodiment provided by the invention is adopted, the reference voltage becomes: 0.825V, the maximum voltage of the cell is also reduced to 0.825V, and the accuracy of the sampling is 0.0008mV (0.825V/1024). The sampling precision of a 12-bit ADC can be achieved.
The battery pack voltage measuring circuit provided by the embodiment of the application samples voltages on each electric core in the battery in a segmented manner, and then performs analog operation processing on each sampling value to determine the voltage of each electric core, so that the sampling precision of the voltages is improved, errors caused by operation in the voltage measuring process are avoided, and the accuracy and reliability of battery voltage measurement are improved.
In order to implement the above embodiments, the present application further provides a voltage measurement system.
The voltage measurement system includes: the battery pack voltage measuring circuit and the battery according to the above embodiments.
The structure and function of the measurement circuit of the voltage measurement system can refer to the detailed description of the above embodiments, and are not repeated here.
Specifically, the voltage measurement system provided in the embodiment of the present application may be applied to any device powered by multiple battery cells, and is used to measure and control the voltage between the battery cells in the battery.
The voltage measurement system of this application embodiment, after carrying out the mining pressure to each electric core through resistance sampling network, carry out analog operation by analog circuit to the sampling voltage to confirm the sampling voltage at each electric core both ends, and then by the controller according to the voltage division ratio of analog sampling voltage and sampling resistance bridge, confirm the actual voltage value at each electric core both ends. Therefore, the voltage of each battery cell is sampled and calculated through the analog circuit, the precision of the sampled voltage is improved, errors caused in the operation process are avoided, conditions are provided for realizing accurate control of each battery cell in the battery, and the reliability and safety of the battery are improved.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
Claims (8)
1. A battery pack voltage measurement circuit, comprising: the voltage sampling network, the voltage processing sub-circuit and the controller are sequentially connected in series;
the voltage sampling network is used for collecting voltage values of all the battery cores in the battery to the ground;
the voltage processing sub-circuit is used for performing analog operation on the voltage values of the battery cells acquired by the voltage sampling network so as to determine sampling voltages at two ends of each battery cell;
the controller is used for determining the actual voltage of each battery cell according to the sampling voltage of each battery cell and the resistance value of the voltage sampling network; the voltage sampling network comprises: n voltage-dividing resistance bridges and L multiplied by N sampling resistance bridges, wherein L and N are positive integers larger than 1;
the voltage processing sub-circuit comprises L multiplied by N voltage processing units and N analog summing circuits;
one end of each of the N voltage-dividing resistance bridges is connected with the ground, and the other end of each of the N voltage-dividing resistance bridges is connected with the anodes of the N battery cells respectively, wherein each voltage-dividing resistance bridge comprises L voltage-dividing resistances;
one end of each of the L multiplied by N sampling resistance bridges is connected with the ground, and the other end of each of the L multiplied by N sampling resistance bridges is connected with one end of each of the L multiplied by N divider resistors, which is far away from the ground;
the input ends of the L × N voltage processing units are respectively connected with the output ends of the L × N sampling resistance bridges, and are used for performing analog operation processing on voltage values output by the L × N sampling resistance bridges to respectively determine L initial sampling voltages of the N battery cells;
the input ends of the N analog summing circuits are respectively connected with the output ends of the L voltage processing units, and are used for performing analog summing processing on the L initial sampling voltages and respectively determining the sampling voltages at two ends of each battery cell.
2. The battery pack voltage measurement circuit of claim 1, wherein the voltage sampling network further comprises: (L-1). times.N third operational amplifiers for isolating the LxN divider resistors from the LxN sampling resistor bridges;
and after the resistor ki and the resistor k (i +1) in the divider resistor bridge are connected, the divider resistor bridge is connected with the input end of a third operational amplifier ki, the output end of the third operational amplifier ki is connected with the input end of the sampling resistor bridge, wherein ki is the resistor in the divider resistor bridge connected with the kth battery cell in parallel, k is a positive integer greater than or equal to 1, and i is a positive integer greater than or equal to 1 and less than or equal to L.
3. The battery pack voltage measurement circuit according to claim 1 or 2, wherein the resistances of the resistors in the voltage dividing resistor bridge are equal.
4. The battery pack voltage measurement circuit of any of claims 1-2, wherein the mth voltage processing unit in the voltage processing sub-circuit comprises: the circuit comprises a first resistor, a second resistor, a first operational amplifier, a switching tube and a third resistor, wherein m is a positive integer which is more than 1 and less than N;
one end of the first resistor is connected with the output end of the (m-1) th resistor bridge, and the other end of the first resistor is connected with the positive input end of the first operational amplifier;
one end of the second resistor is connected with the output end of the mth resistor bridge, and the other end of the second resistor is connected with the negative input end of the first operational amplifier and one end of the switching tube;
the output end of the first operational amplifier is connected with the control end of the switching tube;
the other end of the switch tube is connected with one end of the third resistor;
the other end of the third resistor is connected with the ground.
5. The battery pack voltage measurement circuit of claim 4, wherein the first resistor and the second resistor have equal resistance values.
6. The battery pack voltage measurement circuit of claim 4, wherein the switching transistor is a P-channel metal oxide semiconductor field effect transistor.
7. The battery pack voltage measurement circuit of claim 4, wherein a first one of the voltage processing sub-circuits includes a second operational amplifier;
and the positive input end of the second operational amplifier is connected with the output end of the first resistance bridge, and the negative input end of the second operational amplifier is connected with the output end of the second operational amplifier.
8. A battery voltage measurement system comprising a battery voltage measurement circuit as claimed in any one of claims 1 to 7.
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| CN110187286B (en) * | 2019-05-31 | 2021-09-14 | 蜂巢能源科技有限公司 | Detection circuitry, electrical power generating system and vehicle of copper bar connection status |
| CN110501559B (en) * | 2019-08-27 | 2021-11-09 | 杭州和利时自动化有限公司 | Current collecting device |
| CN112444668A (en) * | 2020-10-09 | 2021-03-05 | 上海纯米电子科技有限公司 | Voltage detection method, device, equipment and medium |
| CN114236226B (en) * | 2021-12-20 | 2023-07-07 | 上海瑞浦青创新能源有限公司 | Voltage measuring circuit |
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| CN102353908A (en) * | 2011-09-30 | 2012-02-15 | 北京国电通网络技术有限公司 | Voltage acquisition system for battery pack |
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| CN102590592A (en) * | 2012-03-05 | 2012-07-18 | 绍兴光大芯业微电子有限公司 | Device for precisely detecting voltage of lithium battery pack |
| JP2014190765A (en) * | 2013-03-26 | 2014-10-06 | Aisin Aw Co Ltd | Voltage detection circuit |
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