Voltage measuring circuit based on battery unit, battery chip and voltage balancing method

Abstract

The invention discloses a voltage measuring circuit based on a battery unit, a battery chip and a voltage balancing method, and relates to the technical field of battery voltage balancing. The first capacitor and the second capacitor are connected with any two battery cells of the corresponding battery unit through the switch matrix, so that the connection relation that the negative electrode is connected with the negative electrode and the positive electrode is connected with the negative electrode between any two battery cells is realized, and voltage values corresponding to the first capacitor and the second capacitor are stored; a first capacitor and a second capacitor are respectively connected with an in-phase end and an anti-phase end of a differential amplifier, so that difference information of two voltage values, namely a specific measurement value of a voltage difference of any two battery cells, is obtained. Through the amplification of the differential amplifier, the voltage measurement precision of the voltage difference between any two battery cells is improved, and the accuracy of voltage balance debugging between the battery cells is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery voltage balancing, and in particular to a voltage measurement circuit, a battery chip and a voltage balancing method based on a battery unit. Background Art

[0002] In order to intelligently manage and maintain each battery unit, prevent the battery from overcharging and over-discharging, extend the battery life, monitor the battery status, and use a battery management system to balance the battery capacity.

[0003] Traditional battery management systems collect the absolute voltage value of each battery cell. Since the voltage collection is greatly affected by temperature, the accuracy of the collected voltage value is low. In order to improve the accuracy of the voltage value, a high-precision analog-to-digital converter (ADC) is used, and its corresponding cost is also increased accordingly. However, the voltage value is determined within the voltage range corresponding to the resolution of the high-precision ADC, which can only determine the voltage range in which the voltage value is located, and still cannot know the true value of the current battery cell, thereby reducing the voltage measurement accuracy of each battery cell, resulting in a decrease in the accuracy of voltage balance debugging between battery cells.

[0004] Therefore, how to improve the voltage measurement accuracy of the battery cell and the accuracy of voltage balance debugging is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a voltage measurement circuit, a battery chip and a voltage balancing method based on a battery cell, so as to solve the technical problems of low voltage measurement accuracy of battery cells collected by a traditional battery management system and reduced accuracy of voltage balancing debugging.

[0006] In order to solve the above technical problems, the present invention provides a voltage measurement circuit based on a battery cell, wherein the voltage measurement circuit comprises a switch matrix, a first capacitor, a second capacitor and a differential amplifier;

[0007] The switch matrix is ​​connected to the battery cells of the battery unit; the first capacitor and the second capacitor are respectively connected to any different battery cells in the battery unit through the switch matrix, so as to realize the connection relationship between the negative electrodes of any two battery cells and the positive electrodes of any two battery cells; wherein the battery unit includes at least two battery cells; and the battery cells are connected in series;

[0008] The first end of each of the first capacitor and the second capacitor is connected to the in-phase end and the inverting end of the differential amplifier respectively; the output end of the differential amplifier is used to output amplified data of the difference between the voltage values ​​of any two battery cells.

[0009] In one aspect, the switch matrix comprises a first switch unit;

[0010] The positive pole of any battery cell passes through the two switches of the first switch unit, and is respectively connected to the first ends of the first capacitor and the second capacitor; the negative pole of any battery cell passes through the other two switches of the first switch unit, and is respectively connected to the second ends of the first capacitor and the second capacitor.

[0011] On the other hand, the acquisition of the amplified data is determined by multiplying the amplification factor of the differential amplifier by the difference between the voltage values ​​of the two arbitrary battery cells; the amplification factor of the differential amplifier is determined by the number of the differential amplifiers connected in series.

[0012] On the other hand, the gain of the differential amplifier is also determined by the resistance relationship between the first resistor and the second resistor of the differential amplifier or by the capacitance relationship between the third capacitor and the fourth capacitor of the differential amplifier.

[0013] On the other hand, it also includes a first AD converter and a processor;

[0014] The first AD converter is connected to the output end of the differential amplifier; and is also connected to the processor;

[0015] The processor is used to determine the target battery cell to be adjusted according to the difference between the voltage values ​​of the arbitrary two battery cells; and adjust according to the resistance value corresponding to the target consumption resistor connected in parallel with the target battery cell to be adjusted to balance the voltage values ​​corresponding to the arbitrary two battery cells.

[0016] On the other hand, a second AD converter is also included;

[0017] The positive electrodes of the battery cells of the battery unit are connected to the second AD converter through the switches of the first switch unit;

[0018] The processor is further used to receive the actual voltage value corresponding to each of the battery cells.

[0019] On the other hand, the number of consumption resistors connected in parallel to the battery cells of the battery unit is the same as the number of the battery cells; and the consumption resistors connected in parallel to the battery cells are in a series relationship.

[0020] In order to solve the above technical problems, the present invention further provides a battery chip, the battery chip comprising a third AD converter and the above-mentioned voltage measurement circuit based on a battery unit; wherein the positive electrode of the last battery cell of the voltage measurement circuit is connected to a load; the load is connected to the negative electrode of the first battery cell of the voltage measurement circuit; the load and each battery cell of the voltage measurement circuit form a current loop;

[0021] The current measuring device is connected to the third AD converter and is used to measure the current of the battery cell in the current loop and convert it into voltage to output to the third AD converter; the third AD converter is connected to the processor.

[0022] In order to solve the above technical problems, the present invention further provides a voltage balancing method based on a battery cell, which is applied to the voltage measurement circuit based on a battery cell described above. The method comprises:

[0023] Determine any two battery cells to be tested;

[0024] According to any two battery cells, switches of the corresponding switch matrix are turned on respectively, so as to store the voltage values ​​corresponding to the any two battery cells into the first capacitor and the second capacitor connected via the switch matrix;

[0025] The output end of the differential amplifier is connected to a processor so that the processor receives amplified data of the difference between the voltage values ​​of any two battery cells output by the output end of the differential amplifier; and the resistance value of the target consumption resistor connected in parallel with the target battery cells to be adjusted corresponding to the any two battery cells is adjusted according to the amplified data so that the voltage values ​​corresponding to any two battery cells are balanced.

[0026] The present invention provides a voltage measurement circuit based on a battery cell, wherein the battery cell includes at least two battery cells; each battery cell is connected in series; a switch matrix is ​​connected to each battery cell of the battery cell; a first capacitor and a second capacitor are respectively connected to any different battery cells in the battery cell through the switch matrix to realize the connection relationship between the negative pole and the positive pole of any two battery cells; the first end of each of the first capacitor and the second capacitor is respectively connected to the in-phase end and the inverting end of the differential amplifier; the output end of the differential amplifier is used to output the amplified data of the difference between the voltage values ​​of any two battery cells. The present invention connects any two battery cells of the corresponding battery cell through the first capacitor and the second capacitor through the switch matrix to realize the connection relationship between the negative pole and the positive pole of any two battery cells, and then the voltage values ​​corresponding to the first capacitor and the second capacitor are stored, and the difference information of the two voltage values ​​is obtained by connecting the first capacitor and the second capacitor to the in-phase end and the inverting end of the differential amplifier respectively, that is, the specific measurement value of the voltage difference between any two battery cells. Through the amplification of the differential amplifier, the voltage measurement accuracy of the voltage difference between any two battery cells is improved, and then the accuracy of the voltage balance debugging between the battery cells is improved. Compared with the traditional voltage test, the high-precision resolution of the AD converter is used to know the voltage range. The present invention obtains the specific measurement value of the voltage difference of the battery cell, which is convenient for subsequent voltage balance debugging and also reduces the cost of the AD converter.

[0027] In addition, the present invention also provides a voltage balancing method based on a battery cell, which has the same beneficial effects as the above-mentioned voltage measuring circuit based on a battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 This is a structural diagram of a traditional battery management system;

[0030] Figure 2 A schematic diagram of a conventional independent voltage measurement solution;

[0031] Figure 3 A structural diagram of a voltage measurement circuit based on a battery cell provided in an embodiment of the present invention;

[0032] Figure 4 A structural diagram of another voltage measurement circuit based on a battery cell provided in an embodiment of the present invention;

[0033] Figure 5 A structural diagram of a differential amplifier provided in an embodiment of the present invention;

[0034] Figure 6 A structural diagram of another differential amplifier provided in real time by the present invention;

[0035] Figure 7 A structural diagram of a voltage measurement circuit based on a battery cell provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The core of the present invention is to provide a voltage measurement circuit, a battery chip and a voltage balancing method based on a battery cell to solve the technical problems of low voltage measurement accuracy of battery cells collected by a traditional battery management system and reduced accuracy of voltage balancing debugging.

[0038] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] After the batteries are connected in series, due to the different capacities of the batteries, the battery with the smallest capacity will be over-discharged first after discharge, which will cause damage to the battery or even permanent damage. During the charging process, the battery with the smallest capacity will be overcharged first, which will also cause damage to the battery or even permanent damage. Therefore, a battery management system is used to balance the battery capacity to achieve battery charge and discharge management.

[0040] Figure 1 The structure diagram of the traditional battery management system is as follows: Figure 1 As shown, the system is explained by taking 3 battery cells as an example. Battery cells B1-B3 are 3 battery cells connected in series. A resistor CNSU1-CNSU3 that consumes electric energy is connected in parallel next to each battery cell. In order to measure the voltage value of the battery, the voltage of each battery cell is measured by a voltage measuring device, that is: the voltage of B1 is V1, the voltage of B2 is V2-V1, and the voltage of B3 is V3-V2. When the battery management system detects that the voltage of a battery cell is too high, it will consume the electric energy of the resistor connected in parallel with the battery cell to achieve passive balance. It can be understood that the resistors CNSU1-CNSU3 are usually not consuming power. They are only turned on when the battery voltage is higher than other battery cells, so that the battery cells with high power can consume energy to balance with other battery cells.

[0041] The capacity of a battery cannot be accurately determined simply by measuring the battery voltage. If individual battery cells age, the internal resistance of the battery cells increases, causing a false increase in the battery cell voltage during charging, leading to a misjudgment that the capacity is too high. At this time, the voltage capacity of the corresponding battery cell is low, and the battery cells that do not need to be discharged will be discharged, causing a vicious cycle. The smaller the capacity, the more it will be discharged.

[0042] Figure 2 A schematic diagram of a traditional independent voltage measurement solution is shown in FIG. Figure 2 As shown, it is composed of switches SC1, SC2 and C. Due to the limited accuracy of ADC, for example, 8-bit accuracy, the corresponding full voltage range has only 256-bit resolution. Taking a 12V lead-acid battery as an example, the full voltage should be measured to 18V (3Vx6) to be sufficient. , measuring the discharge characteristics with an accuracy of 70mV is not enough to reflect the characteristics. It can only determine that the voltage value of the battery cell is within various voltage ranges, but it is impossible to know the true value of the battery cell. In addition, a capacitor C collects the absolute voltage value of the battery cell, and two voltage values ​​need to be collected at different times, resulting in a delay in data collection, and the absolute voltage value collected at the end is inaccurate. Figure 1 and Figure 2 The two ends with a cross in a circle on the left side can be connected to respective loads. The voltage measurement circuit based on a battery unit provided by the present invention can solve the above technical problems.

[0043] Figure 3 A structural diagram of a voltage measurement circuit based on a battery cell provided in an embodiment of the present invention, such as Figure 3 As shown, the voltage measurement circuit includes a switch matrix 2, a first capacitor C1, a second capacitor C2 and a differential amplifier 3;

[0044] The switch matrix 2 is connected to the battery cells of the battery unit 1; the first capacitor C1 and the second capacitor C2 are respectively connected to any different battery cells in the battery unit 1 through the switch matrix 2, so as to realize the connection relationship between the negative electrodes of any two battery cells and the positive electrodes of any two battery cells; wherein the battery unit 1 includes at least two battery cells; and the battery cells are connected in series;

[0045] The first terminals of the first capacitor C1 and the second capacitor C2 are respectively connected to the in-phase terminal and the inverting terminal of the differential amplifier 3; the output terminal of the differential amplifier 3 is used to output the amplified data of the difference between the voltage values ​​of any two battery cells.

[0046] Specifically, the battery unit includes at least two battery cells (in Figure 3 In the embodiment, each battery cell of the battery unit is connected to the switch matrix, and at the same time, the switch matrix is ​​connected to the first capacitor and the second capacitor, so that the first capacitor and the second capacitor are respectively connected to any different battery cells in the battery unit through the switch matrix, so that any two battery cells can realize the connection relationship between the negative electrode and the positive electrode and the positive electrode.

[0047] It should be noted that the battery cells in the battery unit are actually connected in a positive-to-negative connection relationship. In order to achieve a connection relationship between any two battery cells with negative electrodes connected to negative electrodes and positive electrodes connected to positive electrodes, the voltage values ​​corresponding to any two battery cells are stored by the first capacitor and the second capacitor. The first terminals of the first capacitor and the second capacitor are respectively connected to the in-phase terminal and the inverting terminal of the differential amplifier, so that the connection relationship between any two battery cells with negative electrodes connected to negative electrodes and positive electrodes connected to positive electrodes is achieved. The type and amplification factor of the differential amplifier are not limited and can be set according to actual conditions.

[0048] The output terminal of the differential amplifier is used to output amplified data of the difference between the voltage values ​​of any two battery cells.

[0049] The embodiment of the present invention provides a voltage measurement circuit based on a battery cell, wherein the battery cell includes at least two battery cells; each battery cell is connected in series; a switch matrix is ​​connected to each battery cell of the battery cell; a first capacitor and a second capacitor are respectively connected to any different battery cells in the battery cell through the switch matrix to realize the connection relationship between the negative pole and the positive pole of any two battery cells; the first end of each of the first capacitor and the second capacitor is respectively connected to the in-phase end and the inverting end of the differential amplifier; the output end of the differential amplifier is used to output the amplified data of the difference between the voltage values ​​of any two battery cells. The present invention connects any two battery cells of the corresponding battery cell through the first capacitor and the second capacitor through the switch matrix to realize the connection relationship between the negative pole and the positive pole of any two battery cells, and then the voltage values ​​corresponding to the first capacitor and the second capacitor are stored, and the difference information of the two voltage values ​​is obtained by connecting the first capacitor and the second capacitor to the in-phase end and the inverting end of the differential amplifier respectively, that is, the specific measurement value of the voltage difference between any two battery cells. Through the amplification of the differential amplifier, the voltage measurement accuracy of the voltage difference between any two battery cells is improved, and then the accuracy of the voltage balance debugging between the battery cells is improved. Compared with the traditional voltage test, the high-precision resolution of the AD converter is used to know the voltage range. The present invention obtains the specific measurement value of the voltage difference of the battery cell, which is convenient for subsequent voltage balance debugging and also reduces the cost of the AD converter.

[0050] In some embodiments, the switch matrix includes a first switch unit;

[0051] The positive electrode of any battery cell passes through the two switches of the first switch unit and is respectively connected to the first ends of the first capacitor and the second capacitor; the negative electrode of any battery cell passes through the other two switches of the first switch unit and is respectively connected to the second ends of the first capacitor and the second capacitor.

[0052] Specifically, Figure 3 Taking the three battery cells (BAT1, BAT2, BAT3) in the example, the first switch unit is Figure 3In the switch matrix 2, the positive electrode of the first battery cell BAT1 is connected to the first end of the first capacitor C1 and the first end of the second capacitor C2 through the two switches (SW1 and SW3) of the first switch unit. The negative electrode of the first battery cell BAT1 is connected to the second end of the first capacitor C1 and the second end of the second capacitor C2 through the other two switches (SW2 and SW4) of the first switch unit. The positive electrode of the battery cell BAT1 is connected to the negative electrode of the battery cell BAT2, and the positive electrode of the battery cell BAT2 is connected to the first end of the first capacitor C1 and the first end of the second capacitor C2 through the two switches (SX1 and SX3) of the first switch unit; the negative electrode of the battery cell BAT2 is connected to the second end of the first capacitor C1 and the second end of the second capacitor C2 through the other two switches (SX2 and SX4) of the first switch unit. The positive electrode of the battery cell BAT2 is connected to the negative electrode of the battery cell BAT3. The positive electrode of the battery cell BAT3 is connected to the first end of the first capacitor C1 and the first end of the second capacitor C2 through two switches (SY1 and SY3) of the first switch unit; the negative electrode of the battery cell BAT3 is connected to the second end of the first capacitor C1 and the second end of the second capacitor C2 through another two switches (SY2 and SY4) of the first switch unit. In some other embodiments, the switch matrix further includes a second switch unit;

[0053] The second ends of the other two switches of the first switch unit connected to the negative electrode of the battery cell correspond to the first ends of the two switches of the second switch unit respectively; the second ends of the two switches of the second switch unit are both connected to the reference ground.

[0054] Specifically, Figure 4 A structural diagram of another voltage measurement circuit based on a battery cell provided in an embodiment of the present invention, such as Figure 4As shown, taking three battery cells (BAT1, BAT2, BAT3) as an example, based on the connection relationship of the above embodiment, the negative electrode of any battery cell is connected to the second end of the first capacitor C1 and the second end of the second capacitor C2 through the other two switches of the first switch unit 4, and is also connected to the first ends of the two switches of the second switch unit 5. That is, the two switches (SW2 and SW4) connected to the negative electrode of the battery cell BAT1 are respectively connected to the first ends of the two switches (SW5 and SW6) of the second switch unit 5; the two switches (SX2 and SX4) connected to the negative electrode of the battery cell BAT2 are respectively connected to the first ends of the two switches (SW5 and SW6) of the second switch unit 5; and the two switches (SY2 and SY4) connected to the negative electrode of the battery cell BAT3 are respectively connected to the first ends of the two switches (SW5 and SW6) of the second switch unit 5. The two switches of the second switch unit 5 are connected to the reference ground. It can be understood that the reference ground realizes the common mode voltage, the average value of the phasor voltage between each conductor and the specified reference point (usually the earth or the frame), or half of the input voltage simultaneously applied between the two measuring terminals and the common terminal of the voltmeter. For example, when the signal is The system will set the reference ground to 0V. For a system with a low impedance, the reference ground is set to 2.5 V. The reference ground provides a low impedance path so that electromagnetic interference (such as noise, surge, etc.) in the circuit can be quickly discharged through the reference ground, reducing interference with the normal operation of the circuit and improving the stability and reliability of the circuit.

[0055] It should be noted that in this embodiment, the switches of the first switch unit corresponding to the negative electrode and the positive electrode of each battery cell are used separately without a shared connection relationship. The switch provided in this embodiment is only a single-pole single-throw switch, and can also be other single-pole multi-throw switches, which is not limited here. If it is a single-pole multi-throw switch, its corresponding connection relationship will also change.

[0056] The switch matrix provided in this embodiment has a specific connection relationship with each battery cell, so as to realize a connection relationship between any two battery cells, that is, negative electrodes are connected to negative electrodes and positive electrodes are connected to positive electrodes, so as to facilitate the subsequent calculation of the voltage difference between any two battery cells.

[0057] In some embodiments, the acquisition of amplified data is determined by multiplying the amplification factor of the differential amplifier by the difference between the voltage values ​​of any two battery cells; the amplification factor of the differential amplifier is determined by the number of differential amplifiers connected in series.

[0058] Specifically, the amplified data is obtained by multiplying the amplification factor of the differential amplifier by the difference between the voltage values ​​of any two battery cells. The amplification factor can be determined by the number of differential amplifiers in series, and the corresponding number of series can be determined according to actual conditions and is not limited here.

[0059] In some other embodiments, the gain factor of the differential amplifier is further determined by the resistance relationship between the first resistor and the second resistor of the differential amplifier or by the capacitance relationship between the third capacitor and the fourth capacitor of the differential amplifier.

[0060] Specifically, Figure 5 A structural diagram of a differential amplifier provided by an embodiment of the present invention, such as Figure 5 As shown, it is determined by the internal resistance values ​​of the first resistor R1 and the second resistor R2. Figure 5 Take the three differential amplifiers (A1, A2, A3) as an example, the corresponding ,in, . Figure 6 The structural diagram of another differential amplifier provided by the present invention is as follows: Figure 6 As shown in FIG. , it is determined by the capacitance values ​​of the third capacitor (C3, C3') and the fourth capacitor (C4, C4'). It should be noted that , , and The differential amplifier in this embodiment is a switched capacitor differential amplifier, which is only one embodiment, and may be other differential amplifiers. In addition, in other embodiments, internal resistors or internal capacitors may be combined with the differential amplifier to increase the gain of the differential amplifier.

[0061] The gain factor of the differential amplifier provided in this embodiment is determined based on the number of differential amplifiers connected in series, or based on the internal resistance value or internal capacitance value of the differential amplifier, thereby improving the diversity and flexibility of the differential amplifier gain factor determination method.

[0062] In some embodiments, further comprising a first AD converter and a processor;

[0063] The first AD converter is connected to the output end of the differential amplifier and is also connected to the processor;

[0064] The processor is used to determine the target battery cell to be adjusted according to the difference between the voltage values ​​of any two battery cells; and adjust the target battery cell to be adjusted according to the resistance value corresponding to the target consumption resistor connected in parallel to balance the voltage values ​​corresponding to any two battery cells.

[0065] Specifically, Figure 3 , 4As shown, it also includes a first AD converter 6 and a processor 7, wherein the accuracy of the first AD converter 6 is not limited, and the corresponding accuracy can be considered based on the cost of the device. The differential amplifier 3 and the processor 7 need to perform data conversion through the first AD converter 6, so that the processor 7 can determine the battery cell (the target battery cell to be adjusted) whose voltage needs to be adjusted according to the difference between the voltage values ​​of any two battery cells output by the differential amplifier 3, and then adjust it according to the resistance value corresponding to the target consumption resistor connected in parallel with the target battery cell to be adjusted, so as to achieve the voltage value balance of each battery cell in the battery unit. It should be noted that the device corresponding to the target consumption resistor in this embodiment can be an adjustable resistor or a metal-oxide-semiconductor field-effect transistor (MOSFET) device setting, which is not limited here and can be set according to actual conditions. The specific adjustment of the resistance value can be adjusted according to the actual adjustment step size, or it can be adjusted in real time to improve the adjustment accuracy, which is not limited. In addition, in actual scenarios, the target consumption resistor can be inside the battery chip or not inside the battery chip.

[0066] In some embodiments, the number of consumption resistors connected in parallel to the battery cells of the battery unit is the same as the number of the battery cells; and the consumption resistors connected in parallel to the battery cells are in a series relationship.

[0067] It should be noted that in order to improve the efficiency of each battery cell regulation and the accuracy of voltage balance, Figure 3 As shown, the number of consumption resistors (RD1, RD2, ..., RDT), the number of consumption resistors connected in parallel to each battery cell in this embodiment is the same as the number of each battery cell (that is, T=N), and is the same as the series relationship of each battery cell, that is, the consumption resistors connected in parallel to each battery cell are in series relationship.

[0068] The voltage balancing technical solution provided in this embodiment improves the accuracy and efficiency of voltage balancing regulation of the battery cell.

[0069] In some embodiments, further comprising a second AD converter;

[0070] The positive electrodes of the battery cells of the battery unit are connected to the second AD converter through the switches of the first switch unit;

[0071] The processor is also used to receive the actual voltage value corresponding to each battery cell.

[0072] Specifically, Figure 7 A structural diagram of a voltage measurement circuit based on a battery cell is provided in another embodiment of the present invention, such as Figure 7As shown, a second AD converter 8 is also included. The connection relationship of the second AD converter 8 is that the positive electrodes of each battery cell of the battery unit 1 are connected to the second AD converter 8 through each switch of the first switch unit.

[0073] The purpose of the second AD converter in this embodiment is to measure the actual voltage value of each battery cell and send it to the processor so that the processor can compare it with the actual voltage value of each battery cell when adjusting the battery cell to ensure the accuracy of the adjustment.

[0074] Furthermore, the present invention also provides a battery chip, which includes a third AD converter and the above-mentioned voltage measurement circuit based on a battery unit; wherein the positive electrode of the last battery cell of the voltage measurement circuit is connected to the load; the load is connected to the negative electrode of the first battery cell of the voltage measurement circuit; the load and each battery cell of the voltage measurement circuit form a current loop;

[0075] The current measuring device is connected to the third AD converter and is used to measure the current of the battery cell in the current loop and convert it into voltage to output to the third AD converter; the third AD converter is connected to the processor.

[0076] Specifically, Figure 7 As shown, it also includes a load LOAD1, a current measuring device M1 and a third AD converter 9. The positive electrode of the last battery cell (BATN) of the voltage measuring circuit is connected to the load LOAD1, and the load LOAD1 is connected to the negative electrode of the first battery cell (BAT1) of the voltage measuring circuit. The battery cells of the voltage measuring circuit are connected in series, so that the load LOAD1 and the battery cells of the voltage measuring circuit form a current loop.

[0077] The current measuring device M1 is connected to the third AD converter 9, and is used to measure the current of the battery cell of the current loop, convert the current value into a voltage value, and output it to the third AD converter 9. The third AD converter 9 is connected to the processor 7, so that the processor 7 performs subsequent calculation processing based on the voltage value.

[0078] It should be noted that the current measuring device M1 here can be measured by an ammeter, current transformer, Hall effect sensor, resistor shunt, current clamp meter, etc., and can be actually selected according to specific measurement requirements, current range, measurement accuracy and application scenarios, and is not limited here.

[0079] It is worth noting that the battery chip corresponding to this embodiment can be applicable to rechargeable batteries, such as lead-acid batteries, etc., which is not limited here, and can also be applicable to other batteries, which can be set according to actual conditions.

[0080] For an introduction to a battery chip provided by the present invention, please refer to the above method embodiment, which will not be described in detail herein. It has the same beneficial effects as the above voltage measurement circuit based on the battery cell.

[0081] Furthermore, the present invention also provides a voltage balancing method based on a battery cell, which is applied to the above-mentioned voltage measurement circuit based on a battery cell, and the method includes:

[0082] Determine any two battery cells to be tested;

[0083] According to any two battery cells, switches of the corresponding switch matrix are turned on respectively, so as to store the voltage values ​​corresponding to the any two battery cells into the first capacitor and the second capacitor connected via the switch matrix;

[0084] The output end of the differential amplifier is connected to a processor so that the processor receives amplified data of the difference between the voltage values ​​of any two battery cells output by the output end of the differential amplifier; the resistance value of the target consumption resistor connected in parallel with the target battery cells to be adjusted corresponding to any two battery cells is adjusted according to the amplified data so that the voltage values ​​corresponding to any two battery cells are balanced.

[0085] Specifically, the present embodiment determines any two battery cells to be tested, and turns on the switches of the corresponding switch matrix based on the two battery cells, so as to store the corresponding voltage values ​​in the first capacitor and the second capacitor connected via the switch matrix. At the same time, the output end of the differential amplifier is connected to the processor, so that the processor receives the amplified data of the difference between the voltage values ​​of any two battery cells, and thus adjusts the resistance value of the target consumption resistor connected in parallel with the target battery cells to be adjusted corresponding to the any two battery cells according to the amplified data, so as to achieve the voltage value balance corresponding to the any two battery cells.

[0086] For an introduction to a voltage balancing method based on a battery cell provided by the present invention, please refer to the above method embodiment, and the present invention will not be repeated here. It has the same beneficial effects as the above voltage measurement circuit based on a battery cell.

[0087] The above is a detailed introduction to a voltage measurement circuit, a battery chip and a voltage balancing method based on a battery cell provided by the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referenced to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the present invention.

[0088] It should also be noted that, in this specification, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A voltage measurement circuit based on a battery cell, characterized in that: The voltage measurement circuit includes a switch matrix, a first capacitor, a second capacitor and a differential amplifier; The switch matrix is ​​connected to the battery cells of the battery unit; the first capacitor and the second capacitor are respectively connected to any different battery cells in the battery unit through the switch matrix, so as to realize the connection relationship between the negative electrodes of any two battery cells and the positive electrodes of any two battery cells; wherein the battery unit includes at least two battery cells; and the battery cells are connected in series; The first end of each of the first capacitor and the second capacitor is connected to the in-phase end and the inverting end of the differential amplifier respectively; the output end of the differential amplifier is used to output amplified data of the difference between the voltage values ​​of any two battery cells.

2. The voltage measurement circuit based on a battery cell according to claim 1, characterized in that: The switch matrix comprises a first switch unit; The positive electrode of any battery cell passes through the two switches of the first switch unit, and is respectively connected to the first ends of the first capacitor and the second capacitor; the negative electrode of any battery cell passes through the other two switches of the first switch unit, and is respectively connected to the second ends of the first capacitor and the second capacitor.

3. The voltage measurement circuit based on a battery cell according to claim 1 or 2, characterized in that: The amplified data is obtained by multiplying the amplification factor of the differential amplifier by the difference between the voltage values ​​of the two arbitrary battery cells; the amplification factor of the differential amplifier is determined by the number of the differential amplifiers connected in series.

4. The voltage measurement circuit based on a battery cell according to claim 3, characterized in that: The gain of the differential amplifier is also determined by the resistance relationship between the first resistor and the second resistor of the differential amplifier or by the capacitance relationship between the third capacitor and the fourth capacitor of the differential amplifier.

5. The voltage measurement circuit based on a battery cell according to claim 3, characterized in that: Also includes a first AD converter and a processor; The first AD converter is connected to the output end of the differential amplifier; and is also connected to the processor; The processor is used to determine the target battery cell to be adjusted according to the difference between the voltage values ​​of the arbitrary two battery cells; and adjust according to the resistance value corresponding to the target consumption resistor connected in parallel with the target battery cell to be adjusted to balance the voltage values ​​corresponding to the arbitrary two battery cells.

6. The voltage measurement circuit based on a battery cell according to claim 5, characterized in that: Also including a second AD converter; The positive electrodes of the battery cells of the battery unit are connected to the second AD converter through the switches of the first switch unit; The processor is further used to receive the actual voltage value corresponding to each of the battery cells.

7. The voltage measurement circuit based on a battery cell according to claim 5, characterized in that: The number of consumption resistors connected in parallel to the battery cells of the battery unit is the same as the number of the battery cells; and the consumption resistors connected in parallel to the battery cells are in a series relationship.

8. A battery chip, characterized in that: The battery chip includes a third AD converter and a voltage measurement circuit based on a battery cell as described in any one of claims 1 to 7; wherein the positive electrode of the last battery cell of the voltage measurement circuit is connected to a load; the load is connected to the negative electrode of the first battery cell of the voltage measurement circuit; the load and each battery cell of the voltage measurement circuit form a current loop; The current measuring device is connected to the third AD converter and is used to measure the current of the battery cell in the current loop and convert it into voltage to output to the third AD converter; the third AD converter is connected to the processor.

9. A voltage balancing method based on a battery cell, characterized in that: Applied to the battery cell-based voltage measurement circuit as described in claim 1 above, the method comprises: Determine any two battery cells to be tested; According to any two battery cells, switches of the corresponding switch matrix are turned on respectively, so as to store the voltage values ​​corresponding to the any two battery cells into the first capacitor and the second capacitor connected via the switch matrix; The output end of the differential amplifier is connected to a processor so that the processor receives amplified data of the difference between the voltage values ​​of any two battery cells output by the output end of the differential amplifier; and the resistance value of the target consumption resistor connected in parallel with the target battery cells to be adjusted corresponding to the any two battery cells is adjusted according to the amplified data so that the voltage values ​​corresponding to any two battery cells are balanced.

Images