A battery pack equalization detection method, circuit, and integrated circuit

Abstract

This invention discloses a battery pack equalization detection method, relating to electronic technology. The method involves: acquiring the real-time voltage drop of individual cells in the battery pack; obtaining the corresponding high-potential and low-potential voltage values ​​for each individual cell; performing tracking processing on the high-potential and low-potential voltage values ​​respectively; and subtracting the processed high-potential and low-potential voltage values ​​to obtain the overall battery pack voltage drop with the same zero-point potential as the real-time individual cell voltage drop; comparing the overall battery pack voltage drop with the real-time individual cell voltage drop, and determining whether the individual cell voltages are balanced based on the comparison result. This invention also discloses an equalization detection circuit and integrated circuit for battery packs. This invention avoids the problems of large circuit area and high cost caused by using MCUs and complex mixed-signal integrated circuits; and significantly reduces costs while ensuring the equalization control function.

Description

Technical Field

[0001] This invention relates to electronic technology, and more specifically, to a method and circuit for equalization detection of battery packs, and an integrated circuit. Background Technology

[0002] With the gradual maturation and market promotion of new energy technologies, more and more devices, from electric vehicles to drones, from power tools to small home appliances, are using lithium battery packs for power. Lithium batteries are typically assembled into packs in series or parallel. Due to differences in manufacturing processes and application conditions, individual cells can exhibit inconsistencies in characteristics such as voltage, capacity, internal resistance, and self-discharge rate. These inconsistencies increase with the number of cycles, accelerating battery aging and performance degradation, and even posing a risk of thermal runaway. Currently, balancing technology is widely used to improve the inconsistencies between individual cells, increase the usable charge and discharge capacity of the battery pack, and extend battery life, thereby improving the performance and safety characteristics of the assembled battery pack. Some of these technologies have already been widely applied. In addition, balancing hardware is constrained by size, cost, and reliability. When integrated into an electrical system, it must also meet performance requirements such as small size, low cost, fast balancing speed, and high reliability.

[0003] In battery packs, for some balancing circuits and strategies, determining whether the voltage of any single cell in the pack is higher than the average voltage of all cells in the pack is a key control mechanism. For example,

[0004] (1) The HY2213 chip is a common passive equalization control chip. It monitors whether the individual cell voltage has reached the overcharge standard and then performs equalization. However, its disadvantage is that it judges whether equalization is performed based on the overcharge voltage, that is, equalization can only be performed when the charging is about to be fully charged.

[0005] (2) The ETA3000 chip is a common multi-inductor active balancing chip, which detects and compares the voltages of two adjacent cells and balances them. However, due to accuracy limitations, even if balancing is completed in a battery pack with multiple series connections, there may still be a large difference in the voltages of the first and last cells.

[0006] (3) Chips with models such as bq76PL536, MAX17830, and LTC6802-2. These chips are very powerful, capable of detecting the voltage of each individual cell and outputting relevant digital signals, as well as outputting control signals with each cell as a reference ground for controlling active or passive equalization. However, these chips are often expensive. Moreover, they cannot compare the voltage of a single cell with the average voltage of the entire battery pack. In addition, they use a multiplexer (MUX) internally, which cannot measure the voltage of all cells simultaneously; it may take up to 10ms to iterate through the voltage of the entire battery pack. These chips are often used in multi-cell lithium battery packs. If the number of battery pack strings cannot be divided by the maximum number of battery pack strings that a single chip can accommodate, it will result in a waste of chip resources.

[0007] In summary, regardless of the specific chip mentioned above, none of them can independently compare the voltage of a single cell within the battery pack with the average voltage of the entire pack during the battery pack balancing process. Furthermore, the HY2213 and ETA3000 chips cannot determine whether the voltage of any single cell is higher than the average voltage and use this as a basis for balancing. Chips such as the bq76PL536, MAX17830, and LTC6802-2 require the involvement of an external MCU to perform this comparison. This not only wastes chip resources but also hinders the overall integration of the balancing circuit and makes it difficult to reduce costs. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a battery pack equalization detection method, circuit, and integrated circuit. This method compares the voltage of any single cell in the battery pack with the average voltage of all cells in the battery pack, avoiding the problems of large circuit area and high cost caused by using MCUs and complex mixed-signal integrated circuits. It greatly reduces costs while ensuring the equalization control function.

[0009] The present invention discloses an equalization detection method for battery packs, the method comprising:

[0010] Set a single-cell voltage division ratio, and collect the real-time single-cell voltage drop of the individual cells in the battery pack according to the single-cell voltage division ratio;

[0011] The battery pack is subjected to voltage division processing to obtain high potential voltage values ​​and low potential voltage values ​​corresponding to the individual cells, and the voltage difference between the high potential voltage value and the low potential voltage value is the balanced voltage drop value after dividing the average voltage of the entire battery pack by the individual cell voltage division ratio.

[0012] The high-potential voltage value and the low-potential voltage value are respectively followed, and the high-potential voltage value and the low-potential voltage value after the following processing are subtracted to obtain the whole group of single-cell voltage drops with the same zero-point potential as the real-time single-cell voltage drops.

[0013] The voltage drop of the entire battery pack is compared with the real-time voltage drop of the individual cells, and the voltage of the individual cells in the battery pack is determined based on the comparison result to determine whether the voltage of the individual cells in the battery pack is balanced.

[0014] The high-potential voltage value and the low-potential voltage value are both located between the potentials of the corresponding individual cells in the battery pack.

[0015] A battery pack equalization detection circuit includes an overall voltage divider structure and multiple components connected to individual cells B. n The output terminals are connected one-to-one with the single-cell voltage divider structure, the common-ground conversion structure, and the comparator U. n2 ;

[0016] The single-cell voltage divider structure is used to adjust the single-cell battery B according to the set single-cell voltage divider ratio. n The output voltage is divided and the real-time individual unit voltage drop is output.

[0017] The voltage divider structure is used to divide the voltage of the battery pack and output voltage to the individual battery B. n The corresponding high potential voltage value and the low potential voltage value that is greater than the negative electrode potential of the single cell, and the voltage difference between the high potential voltage value and the low potential voltage value is the balanced voltage drop value after dividing the average voltage of the entire cell of the battery pack by the single cell voltage division ratio.

[0018] The common-ground conversion structure is used to follow the high potential voltage value and the low potential voltage value respectively, and to perform a subtraction operation on the high potential voltage value and the low potential voltage value after the following processing, so as to obtain the whole group of individual voltage drops with the same zero potential as the real-time individual voltage drops.

[0019] The comparator U n2 It is used to compare the voltage drop of the entire group of individual cells with the real-time voltage drop of individual cells and obtain the comparison result.

[0020] The integrated voltage-degrading structure includes N resistors R n3 Resistance R n4 N resistors R n3 Resistance R n4 The components are connected in series at intervals to form a series cluster. The resistances at both ends of the series cluster are denoted as resistances R. N4 and resistance R 13 The resistor R N4 The resistor R is connected to the positive output terminal of the battery pack.13 Through resistor R 04 Connected to the negative output terminal of the battery pack; the resistor R n3 The two ends are respectively used as the single cell B n Corresponding high-potential voltage output terminal and low-potential voltage output terminal;

[0021] Where N is a natural number of 2 or higher; and n is any value from 1 to N.

[0022] The resistor RN4 and resistor R 04 The sum of the values ​​equals the value divided by the resistance R. N4 Any resistor R other than n4 The value of .

[0023] The single-unit voltage divider structure includes a resistor R. n1 and resistance R n2 The resistor R n1 One end is connected to the single cell B n The negative output terminal is connected, and the resistor R n2 One end is connected to the single cell B n The positive output terminal is connected, and the resistor R n1 The other end is connected to resistor R n2 The other end is connected, and the resistor R n1 and resistance R n2 The connection end is the output end of the single-unit voltage divider structure.

[0024] The resistor R n1 and resistance R n2 The ratio is equal to the resistance R. n3 and the resistor R N4 Any resistor R other than n4 The ratio of .

[0025] The common-ground conversion structure includes an operational amplifier U. n3 Operational amplifier U n4 and subtractor; the operational amplifier U n3 The power input terminal and the single cell B n The output terminal of the operational amplifier U is connected. n3 The non-inverting input terminal of the operational amplifier U is connected to the low-potential output terminal. n3 The inverting input terminal is connected to its output terminal, and the operational amplifier U n3 The output terminal of the operational amplifier is connected to the inverting input terminal of the subtractor; the operational amplifier U n4 The power input terminal and the single cell B n The output terminal of the operational amplifier U is connected. n4 The non-inverting input terminal of the operational amplifier U is connected to the high-potential voltage output terminal.n4 The inverting input terminal is connected to its output terminal, and the operational amplifier U n4 The output terminal of the subtractor is connected to the non-inverting input terminal of the subtractor; the output terminal of the subtractor is connected to the comparator U. n2 The inverting input terminal of the comparator U is connected. n2 The non-inverting input terminal of the comparator U is connected to the output terminal of the single-unit voltage divider structure. n2 The power input terminal and the single cell B n Connect the output terminal.

[0026] The subtractor includes an operational amplifier U. n1 The operational amplifier U n1 The power input terminal and the single cell B n The output terminal of the operational amplifier U is connected. n1 The inverting input terminal is connected to resistor R. n5 With operational amplifier U n3 The output terminal of the operational amplifier U is connected. n1 The non-inverting input terminal is connected to a resistor R. n6 With operational amplifier U n4 The output terminal of the operational amplifier U is connected, and the operational amplifier U n1 The non-inverting input terminal is also connected to a resistor R. n7 Grounded; the operational amplifier U n1 The inverting input terminal is connected to resistor R. n8 Connect it to its output terminal.

[0027] An integrated circuit for a battery pack includes a circuit package, wherein the equalization detection circuit is integrated within the circuit package.

[0028] Beneficial effects

[0029] The advantages of this invention are:

[0030] (1) The voltage of a single cell and the voltage corresponding to the single cell in the battery pack are collected by voltage division processing. The voltage drop of the entire group of cells is grounded with the real-time single cell voltage drop by voltage tracking and common ground processing. The voltage of the single cell can be judged by comparison by a comparator. It can compare the voltage of any single cell in the battery pack with the average voltage of the entire group of cells in the battery pack without using MCU and dedicated battery management chip.

[0031] (2) Since the detection circuit uses components such as resistors and operational amplifiers, it achieves the comparison of the average voltage of a single cell with the average voltage of the entire battery pack without using an MCU or a dedicated battery management chip. This avoids the problems of large circuit area and high cost caused by using an MCU and complex mixed-signal integrated circuits. It greatly reduces costs while ensuring the equalization control function.

[0032] (3) Since the voltage divider structure, common ground conversion structure, and comparator are set according to the number of individual cells, and the resistor settings in the overall voltage divider structure are also set according to the number of individual cells, the number of individual cells in series can be freely combined to form an equalization detection circuit. Therefore, there is no problem of wasting chip resources due to using a dedicated battery management chip but not fully utilizing the number of battery strings. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the equalization detection circuit structure of the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0035] The present invention provides a battery pack equalization detection method, which sets a single-cell voltage division ratio and collects the real-time single-cell voltage drop of individual cells in the battery pack according to the single-cell voltage division ratio.

[0036] The battery pack is subjected to voltage division to obtain high-potential voltage values ​​and low-potential voltage values ​​corresponding to individual cells, and the voltage difference between the high-potential voltage value and the low-potential voltage value is the balanced voltage drop value after dividing the average voltage of the entire battery pack by the individual cell voltage division ratio.

[0037] The high-potential voltage value and the low-potential voltage value are both located between the potentials of their corresponding individual cells in the battery pack.

[0038] The high-potential voltage value and the low-potential voltage value are followed separately, and the high-potential voltage value and the low-potential voltage value after the following processing are subtracted to obtain the group of individual cell voltage drops with the same zero-point potential as the real-time individual cell voltage drops.

[0039] By performing follow-up processing on the acquired voltage, the reliability of the acquired voltage signal can be ensured, making the comparison results more accurate and effective.

[0040] The voltage drop of the entire battery pack is compared with the real-time voltage drop of the individual cells. Based on the comparison results, it is determined whether the voltage of the individual cells in the battery pack is balanced.

[0041] By using voltage divider processing, the voltage of individual cells and the voltage corresponding to individual cells in the battery pack are collected. Through voltage tracking and common ground processing, the collected voltage drop of the entire group of cells is grounded with the real-time voltage drop of individual cells. Then, by comparing the voltages of individual cells, it can be determined whether the individual cell voltages are balanced. This method can collect, process and compare the voltage of any individual cell in the battery pack with the average voltage of the battery pack without using an MCU or a dedicated battery management chip.

[0042] See Figure 1 A battery pack equalization detection circuit includes an overall voltage divider structure and multiple components connected to individual cells B. n The output terminals are connected one-to-one with the single-cell voltage divider structure, the common-ground conversion structure, and the comparator U. n2 Among them, the single-unit voltage divider structure, the common-ground conversion structure, and the comparator U n2 This constitutes a substructure for equalization detection, with each individual cell B n Each is connected to a substructure. The overall voltage-degrading structure is a reused structure, used for each individual cell B. n Provides the corresponding total unit voltage drop.

[0043] Furthermore, the single-cell voltage divider structure is used to adjust the single-cell battery B according to the set single-cell voltage divider ratio. n The output voltage is divided and output in real time the individual unit voltage drop.

[0044] Specifically, the single-unit voltage divider structure includes resistor R n1 and resistance R n2 Resistance R n1 One end is connected to the single cell B n Connect the negative output terminal to resistor R. n2 One end is connected to the single cell B n Connect the positive output terminal to resistor R. n1 The other end is connected to resistor R n2 The other end is connected, and the resistor R n1 and resistance R n2 The connection terminal is the output terminal of the single-cell voltage divider structure. Two resistors are used to connect the single-cell battery B. n The voltage divider is to avoid the floating resistor R n4 The voltage divider exceeds the operational amplifier U. n1 The circuit may be damaged due to an input range (including below the lower limit and above the upper limit).

[0045] In this embodiment, the monomer partial pressure ratio = R n1 / (R n1 +R n2 ).

[0046] The entire voltage divider structure is used to divide the voltage of the battery pack and output it to the individual battery cells B. n The corresponding high potential voltage value and the low potential voltage value that is greater than the negative electrode potential of the single cell are used to make the voltage difference between the high potential voltage value and the low potential voltage value equal to the voltage drop value after dividing the average voltage of the entire cell in the battery pack by the single cell voltage division ratio.

[0047] It should be noted that the average voltage of the entire battery pack is the average voltage obtained by dividing the total voltage of the battery pack by the number of individual cells. The equalization voltage drop value is calculated as (total voltage of the battery pack / number of individual cells) × individual cell voltage division ratio.

[0048] Specifically, the entire voltage divider structure includes N resistors R n3 Resistance R n4 N resistors R n3 Resistance R n4 These are connected in series at intervals to form a series cluster. The resistances at both ends of the series cluster are denoted as resistances R. N4 and resistance R 13 Resistance R N4 Connected to the positive output terminal of the battery pack, resistor R 13 Through resistor R 04 Connect to the negative output terminal of the battery pack; resistor R n3 The two ends are respectively used as the single cell B n Corresponding high-potential voltage output terminals and low-potential voltage output terminals.

[0049] Where N is a natural number of 2 or higher; and n is any value from 1 to N.

[0050] For a total of N individual cells B n For the battery pack as a whole, for any single cell B n There are two resistors R connected in series. n1 R n2 Directly with single cell B n Connected. Resistor R n3 Resistance R n4 These are two adjacent resistors on the resistor string of the entire voltage divider structure. The resistor string of this entire voltage divider structure consists of R... 04 R 13 R 14 R 23 R 24 R 33 R 34 ..., R( N -1)3、R( N -1)4、R N3 R N4 It is connected in series. The resistor R is... 04One end is connected to the negative output terminal of the battery pack, and the resistor R N4 The other end is connected to the positive output terminal of the battery pack.

[0051] In the overall voltage-splitting structure, it is necessary to collect data from the Mth individual cell B. M The corresponding high-potential voltage value and low-potential voltage value. That is, the resistance R. M3 The terminal voltage. Where M is any value from 1 to N.

[0052] Assume the terminal voltage of the battery pack is V. N The Mth single cell B M The corresponding high potential voltage value is V H The Mth single cell B M The corresponding low potential voltage value is V L .but

[0053] V H =V N ×(R 04 +R 13 +R 14 +…+R( M-1 )3+R( M-1 )4+R M3 ) / (R N4 +R N3 +…+R 13 +R 14 +R 04 );

[0054] V L =V N ×(R 04 +R 13 +R 14 +…+R( M-1 )3+R( M-1 )4) / (R N4 +R N3 +…+R 13 +R 14 +R 04 ).

[0055] As can be seen from the above formula, the output of the entire voltage-dividing structure is the same as that of the single cell B. n The corresponding resistance R n3 The voltage value at both ends. For example, when it is necessary to detect the balance between the voltage of a single cell B2 and the equalization voltage drop value of the battery pack, the voltage collector of the entire voltage group is sampled by the resistance R. 23 The voltage at both ends.

[0056] Preferably, except for the resistance R N4 Any resistor R other than n4 All resistors R have the same value.n3 The values ​​of all resistors are the same. N4 and resistance R 04 The sum of the values ​​equals the value divided by the resistance R. N4 Any resistor R other than n4 The value of R. In addition, the resistance R. n1 and resistance R n2 The ratio is equal to the resistance R. n3 and the resistor R N4 Any resistor R other than n4 The ratio of .

[0057] From the above proportional relationship of resistances, it can be seen that resistance R N4 and resistance R 04 It can be viewed as being composed of a resistor R N4 Other resistors R n4 It is split into parts. This is mainly to ensure that the low-potential voltage value is greater than the negative electrode potential of the individual cell, thereby ensuring the integrity of the voltage difference between the obtained low-potential voltage value and the high-potential voltage value.

[0058] To better illustrate the above analysis, let's assume that when designing the entire voltage divider structure, it only uses N resistors R n3 Resistance R n4 A series cluster is formed by connecting resistors in series at intervals. That is, all resistors R... n3 All resistors R have the same resistance value. n4 The resistance values ​​are consistent, and no resistor R is provided. 04 Under this design, if cell B in the battery pack... n When in an unbalanced state, in a certain single cell B n The negative electrode potential is higher than that of the single cell B. n At corresponding low potential voltage values, since both the follower and the subtractor are composed of single cell B n Power supply, therefore for this single cell B n The voltage difference obtained by subtracting the corresponding low-potential voltage value from the high-potential voltage value will be less than the actual equilibrium voltage drop value. That is, the final voltage difference is the high-potential voltage value minus the value of cell B. n It is the negative potential, not the difference between the low potential voltage value and the high potential voltage value.

[0059] To solve the above problems, this application provides a resistor R. 04 And this resistor is related to resistor R N4 The sum of the resistances is divided by the resistance R. N4 Any resistor R other than n4 The value of . Due to the resistance R 04 Connected to resistor R 13Between the negative terminal of cell B1 and the negative terminal of the single cell, therefore, through the resistor R 04 Its function is to reduce the terminal voltage of other resistors in the entire voltage-degrading structure (except for the resistor R at the positive output terminal of the battery pack). N4 The boost is performed on one end. The specific boost value is...

[0060] V0 = V N ×[R 04 / (N×(R n3 +R n4 ))).

[0061] Furthermore, this boost value must satisfy the condition that the low-potential voltage value after the voltage boost is greater than the corresponding negative electrode potential of the individual cell. This ensures that the voltage difference between the final collected low-potential voltage value and the high-potential voltage value is equal to the equilibrium voltage drop value.

[0062] And this relates to the resistance R N4 and resistance R 04 The resistance value allocation ratio only needs to meet the above-mentioned improvement value requirements. Looking at the current unbalanced battery packs, the resistance R... N4 and resistance R 04 A resistor ratio of 1:1, 1:2, or 1:3 can all meet the requirements. Below, we will use resistor R... N4 and resistance R 04 The resistance ratio is taken as 1:1 for explanation.

[0063] The following is an example illustrating whether the overall voltage division structure in this embodiment can collect a voltage that is consistent with the equal voltage drop value.

[0064] For example, resistor R n1 and resistance R n2 The resistance values ​​are the same. That is, in this embodiment, the resistance of single cell B is the same. n The voltage is divided into two equal parts, and the real-time single-cell voltage drop collected is the single-cell battery B. n Half of the voltage. In the series cluster of this embodiment, except for the resistor R N4 All other resistors have the same resistance value; resistor R N4 The resistance value and resistance R 04 The resistance values ​​are the same, and the resistance R 04 The resistance value and the resistance R in the series cluster are different. N4 The ratio of any resistor other than the one in the ratio is 1:2.

[0065] That is, the resistance ratio in the overall voltage divider structure and the individual voltage divider structure is: Resistance R n1 With resistance R n2 The resistance ratio is 1:1; except for resistor R 04 With resistance R N4 In addition, resistor Rn3 With the remaining resistor R n4 The resistance ratio is 1:1; resistor R 04 With resistance R N4 The two resistors have the same resistance value, and the two resistors are the same as resistor R. n4 The resistance ratio of each resistor is 1:2, that is, resistor R 04 Add resistor R N4 The resistance value is equal to the resistance R. n4 The resistance value.

[0066] The following section will verify whether the entire voltage-dividing structure can collect a voltage equal to the equal voltage drop value, based on the above proportional relationship.

[0067] Based on the above proportional relationship, the high potential voltage value obtained above is V. H With a low potential voltage value of V L The formula can be simplified to:

[0068] V H =V N ×[R 04 +(M-1)×R( M-1 )4+M×R M3 ] / (N×R n4 +N×R n3 );

[0069] V L =V N ×[R 04 +(M-1)×R( M-1 )4+(M-1)×R( M-1 )3] / (N×R n4 +N×R n3 ).

[0070] V H With V L By performing subtraction, we obtain the result.

[0071] V H -V L =(V N ×R M3 ) / (N×R n4 +N×R n3 )

[0072] =(V N / N)×[R n3 / (R n4 +R n3 )]

[0073] =V N / 2N.

[0074] It should be noted that R in the above three formulas n4 To remove resistance R N4 Any resistor R other than n4 The resistance value.

[0075] Furthermore, since the equalization voltage drop value = (total battery pack voltage / number of individual cells) × individual cell voltage division ratio; and the individual cell voltage division ratio = R n1 / (R n1 +R n2 = 1 / 2. Therefore, the equalization voltage drop value can be expressed as: equalization voltage drop value = (total battery pack voltage / number of individual cells) × 1 / 2.

[0076] According to the above calculation results, the voltage difference between the high potential voltage value and the low potential voltage value obtained by the integrated voltage divider structure in this embodiment is the equal voltage drop value.

[0077] For example, when the resistance R n1 The value is 102kΩ, and the resistance R is... n2 When the resistance is 510kΩ, the ratio is 1:5.

[0078] In this case, if the resistance R n3 If the resistance value is 102kΩ, then the resistance R N4 With resistance R 04 The resistance value is 255kΩ, and the resistor R is... n4 The resistance value is set to 510kΩ. Using this setting, and based on the verification method described above, the voltage difference between the high and low potential voltages obtained by the entire voltage divider structure can be determined as the equilibrium voltage drop value.

[0079] For example, when the resistance R n1 The value is 130kΩ, and the resistance R is... n2 When the resistance is 390kΩ, the ratio is 1:3.

[0080] In this case, if the resistance R n3 If the resistance value is 150kΩ, then the resistance R N4 With resistance R 04 The resistance value is 225kΩ, and the resistor R is... n4 The resistance is set to 450kΩ. Under this ratio, the voltage difference between the high-potential voltage and the low-potential voltage obtained by the entire voltage divider structure can also be obtained through the above verification method, which is the equilibrium voltage drop value.

[0081] It should be noted that the specific resistor values ​​mentioned above are only some of the implementation methods and are not limited to the values ​​described above. When selecting resistor values, it is only necessary to satisfy the above-mentioned resistance ratio relationship and choose a resistor with a value suitable for this circuit, such as a resistor in the range of kilohms to hundreds of kilohms.

[0082] Since this embodiment involves extracting data from each individual battery cell B... n The voltage collected is compared with the voltage collected after balancing the individual cells in the battery pack by simulating the voltage distribution structure of the entire battery pack, thus avoiding voltage fluctuations between adjacent cells. n The problem of large voltage errors at the beginning and end of the entire string caused by imbalance is greatly improved, thus significantly enhancing the reliability of the detection.

[0083] The common-ground conversion structure is used to perform follow-up processing on the high-potential voltage value and the low-potential voltage value respectively, and to perform subtraction operation on the high-potential voltage value and the low-potential voltage value after follow-up processing to obtain the group of individual cell voltage drops with the same zero-point potential as the real-time individual cell voltage drops.

[0084] Specifically, the common-ground conversion structure includes operational amplifier U n3 Operational amplifier U n4 Subtractor; Operational amplifier U n3 The power input terminal and the single cell B n The output terminal is connected to the operational amplifier U. n3 The non-inverting input terminal is connected to the low-potential output terminal, and the operational amplifier U... n3 The inverting input terminal is connected to its output terminal, and the operational amplifier U n3 The output terminal of the amplifier is connected to the inverting input terminal of the subtractor; the operational amplifier U n4 The power input terminal and the single cell B n The output terminal is connected to the operational amplifier U. n4 The non-inverting input terminal is connected to the high-potential output terminal, and the operational amplifier U... n4 The inverting input terminal is connected to its output terminal, and the operational amplifier U n4 The output terminal of the subtractor is connected to the non-inverting input terminal of the subtractor; the output terminal of the subtractor is connected to the comparator U. n2 The inverting input terminal is connected to the comparator U. n2 The non-inverting input terminal is connected to the output terminal of the single-unit voltage divider structure, and the comparator U n2 The power input terminal and the single cell B n Connect the output terminal.

[0085] Among them, comparator U n2 It is used to compare the voltage drop of the entire group of individual cells with the real-time voltage drop of individual cells and obtain the comparison result.

[0086] The subtractor includes an operational amplifier U n1 Operational amplifier U n1 The power input terminal and the single cell B n The output terminal is connected to the operational amplifier U. n1The inverting input terminal is connected to resistor R. n5 With operational amplifier U n3 The output terminal is connected to the operational amplifier U. n1 The non-inverting input terminal is connected to a resistor R. n6 With operational amplifier U n4 The output terminal is connected, and the operational amplifier U n1 The non-inverting input terminal is also connected to a resistor R. n7 Grounding; Operational amplifier U n1 The inverting input terminal is connected to resistor R. n8 Connect it to its output terminal.

[0087] Specifically, the common-ground switching structure in this embodiment includes four operational amplifiers, one of which is connected to a resistor R. n5 To resistor R n8 It forms the subtractor U n1 Among them, the resistance R n5 To resistor R n8 The resistance values ​​are the same. Another operational amplifier forms the comparator U. n2 The inverting inputs of the remaining two operational amplifiers are directly connected to their respective outputs, forming operational amplifier U. n3 and operational amplifier U n4 All four operational amplifiers are derived from the single cell B under test. n Direct power supply. Operational amplifier U n3 Operational amplifier U n4 The two input terminals are respectively connected to resistor R n3 The two ends are connected, subtractor U n1 The two input terminals are respectively connected to operational amplifier U n3 Operational amplifier U n4 The two output terminals are connected, and the subtractor U n1 The output of the comparator U n2 The inverting input terminal of the comparator is connected to the non-inverting input terminal, and the non-inverting input terminal of the comparator is connected to the resistor R. n1 Resistance R n2 The nodes are connected in series.

[0088] In implementation, the four operational amplifiers can be identical. However, since the four operational amplifiers perform different functions, their parameters, such as offset voltage, offset current, gain-bandwidth product, slew rate, and whether they are rail-to-rail outputs, can be adjusted according to their functions during design. The methods for adjusting the operational amplifier parameters are all well-known in the art, and the technical solution of this embodiment does not improve upon them; therefore, they will not be described in detail here.

[0089] Due to the single-cell voltage divider structure, common-ground conversion structure, and comparator U in this embodiment n2 According to cell Bn The quantity setting, and the resistor setting in the entire voltage-dividing structure, are also based on the individual cell B. n Quantity setting. Therefore, single-cell battery B can be installed. n The circuit allows for flexible combination of the number of battery cells in series for equalization detection, thus eliminating the problem of wasted chip resources caused by using a dedicated battery management chip but not fully utilizing the number of battery cells in series. Furthermore, this circuit avoids the use of multiplexers, enabling real-time comparison of the voltage drop of each individual cell with the overall voltage drop of the battery pack, eliminating any delay.

[0090] Since battery packs and supercapacitor packs have similar properties, the technical solution in this embodiment can be applied to supercapacitor packs in addition to battery packs.

[0091] An integrated circuit for battery packs includes a circuit package, within which the aforementioned equalization detection circuit is integrated, thereby achieving a high degree of integration of the equalization detection circuit.

[0092] The four operational amplifiers can be designed with individual packages or integrated into a single package for high integration to meet specific requirements. Furthermore, since the equalization detection circuit does not utilize high-power components, a subtractor U can also be integrated into the package along with the four operational amplifiers. n1 The resistor R in n5 To resistor R n8 Further optimization is possible by integrating all four operational amplifiers and all external resistors into a single package, thereby further improving the circuit's integration level.

[0093] Furthermore, it's even possible to integrate operational amplifiers four times the number of battery cells and external resistors into a single package, allowing one package to handle multiple battery cells. In this case, an enable pin can be provided for all on-chip operational amplifiers, which can be used to shut down all operational amplifiers when equalization is not required, thus achieving lower standby current. Alternatively, analog switches can be placed between the internal resistor strings and their respective pins, also controlled by the enable pin, to disconnect the two resistor strings from the battery cell when equalization is not needed, thereby achieving even lower standby current.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. An equalization detection circuit for a battery pack, characterized in that, The whole set voltage dividing structure and a plurality of single cell voltage dividing structures corresponding to the output terminals of the single cells Bn, a common ground conversion structure, and a comparator Un2 are included. The whole set voltage dividing structure is configured to divide the voltage of the battery pack and output a high voltage value corresponding to the single cells Bn and a low voltage value greater than the negative voltage of the single cells, and the voltage difference between the high voltage value and the low voltage value is an equalization voltage drop value obtained by dividing the average voltage of the whole set of single cells by a single cell voltage dividing ratio. The common ground conversion structure is configured to perform following processing on the high voltage value and the low voltage value respectively, and perform subtraction operation on the following high voltage value and the following low voltage value to obtain a whole set single cell voltage drop voltage having the same zero voltage as the real-time single cell voltage drop voltage. The comparator Un2 is configured to perform comparison operation on the whole set single cell voltage drop voltage and the real-time single cell voltage drop voltage to obtain a comparison result. The whole set voltage dividing structure includes N resistors Rn3 and resistors Rn4, and the N resistors Rn3 and the resistors Rn4 are connected in series with intervals to form a series cluster, and the resistors at both ends of the series cluster are denoted as a resistor RN4 and a resistor R13 respectively; the resistor RN4 is connected to the positive output terminal of the battery pack, and the resistor R13 is connected to the negative output terminal of the battery pack through a resistor R04; the two ends of the resistor Rn3 are used as the high voltage value output terminal and the low voltage value output terminal corresponding to the single cell Bn respectively. N is a natural number greater than or equal to 2, and n is any number from 1 to N. The sum of the resistor RN4 and the resistor R04 is equal to the value of any resistor Rn4 except the resistor RN4. The single cell voltage dividing structure includes a resistor Rn1 and a resistor Rn2; one end of the resistor Rn1 is connected to the negative output terminal of the single cell Bn, one end of the resistor Rn2 is connected to the positive output terminal of the single cell Bn, the other end of the resistor Rn1 is connected to the other end of the resistor Rn2, and the connection end of the resistor Rn1 and the resistor Rn2 is the output terminal of the single cell voltage dividing structure. The ratio of the resistor Rn1 and the resistor Rn2 is equal to the ratio of the resistor Rn3 and any resistor Rn4 except the resistor RN4.

2. The equalization detection circuit for a battery pack according to claim 1, characterized by, The common ground conversion structure comprises an operational amplifier Un3, an operational amplifier Un4 and a subtractor; a power input end of the operational amplifier Un3 is connected with an output end of the single battery Bn, a non-inverting input end of the operational amplifier Un3 is connected with the low potential voltage value output end, an inverting input end of the operational amplifier Un3 is connected with its output end, and the output end of the operational amplifier Un3 is connected with an inverting input end of the subtractor; a power input end of the operational amplifier Un4 is connected with the output end of the single battery Bn, a non-inverting input end of the operational amplifier Un4 is connected with the high potential voltage value output end, an inverting input end of the operational amplifier Un4 is connected with its output end, and the output end of the operational amplifier Un4 is connected with a non-inverting input end of the subtractor; an output end of the subtractor is connected with an inverting input end of the comparator Un2, a non-inverting input end of the comparator Un2 is connected with an output end of the single voltage dividing structure, and a power input end of the comparator Un2 is connected with the output end of the single battery Bn.

3. The equalization detection circuit for a battery pack according to claim 2, characterized by The subtractor comprises an operational amplifier Un1; a power input end of the operational amplifier Un1 is connected with the output end of the single battery Bn, an inverting input end of the operational amplifier Un1 is connected with the output end of the operational amplifier Un3 through a resistor Rn5, a non-inverting input end of the operational amplifier Un1 is connected with the output end of the operational amplifier Un4 through a resistor Rn6, and the non-inverting input end of the operational amplifier Un1 is also connected with the ground through a resistor Rn7; and an inverting input end of the operational amplifier Un1 is connected with its output end through a resistor Rn8.

4. A battery equalization detection method for a battery equalization detection circuit according to claim 1, characterized by, The high potential voltage value and the low potential voltage value are both between the potential of the single battery corresponding to the battery pack.

5. An integrated circuit for a battery pack, characterized by comprising: The application further provides a circuit package, wherein the equalization detection circuit is integrated in the circuit package.

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