A multi-channel battery voltage detection circuit with equalization function

Abstract

The utility model relates to battery voltage detection, specifically relates to a kind of multi-channel battery voltage detection circuit with equalization function, multiplexer module is connected between the battery pack to be measured and analog front-end sampling chip AFE, under the control of controller MCU, corresponding channel is selected to pass battery voltage signal to analog front-end sampling chip AFE, while corresponding channel is selected to carry out passive equalization and active equalization to the battery pack to be measured;Analog front-end sampling chip AFE is connected between multiplexer module and controller MCU, battery voltage signal is sent to controller MCU, realizes battery voltage detection, while under the control of controller MCU, the passive equalization of the battery pack to be measured is realized using the discharge channel of itself;The technical scheme provided by the utility model can effectively overcome the defects that the voltage of each lithium battery in parallel battery module cannot be accurately and quickly detected, and the function of battery voltage detection circuit is single.

Description

Technical Field

[0001] This utility model relates to battery voltage detection, specifically to a multi-channel battery voltage detection circuit with equalization function. Background Technology

[0002] Currently, voltage detection circuits for parallel battery modules in lithium battery packs suffer from problems such as complex design, numerous required components, and high cost. Furthermore, under certain operating conditions, they cannot accurately and quickly detect the voltage of each lithium battery cell in the parallel module. In addition, existing lithium battery pack balancing methods are typically divided into passive balancing and active balancing. Passive balancing generally uses discharge resistors, resulting in energy waste; active balancing often uses DC-DC modules, which suffer from high cost and difficulties in miniaturization. Utility Model Content

[0003] (a) Technical problems to be solved

[0004] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a multi-channel battery voltage detection circuit with equalization function, which can effectively overcome the shortcomings of the existing technology, such as the inability to accurately and quickly detect the voltage of each lithium battery in the parallel battery module, and the single function of the battery voltage detection circuit.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A multi-channel battery voltage detection circuit with equalization function includes a battery pack under test, a power supply selection module, a multiplexer module, an analog front-end sampling chip (AFE), and a controller MCU.

[0008] The power supply selection module is connected to the battery pack under test and selects the battery string in the power supply path under the control of the controller MCU.

[0009] The multiplexer module is connected between the battery pack under test and the analog front-end sampling chip (AFE). Under the control of the controller MCU, it transmits the battery voltage signal to the analog front-end sampling chip (AFE) by selecting the corresponding channel. At the same time, it performs passive and active equalization on the battery pack under test by selecting the corresponding channel.

[0010] The analog front-end sampling chip (AFE) is connected between the multiplexer module and the controller MCU. It sends the battery voltage signal to the controller MCU to realize battery voltage detection. At the same time, under the control of the controller MCU, it uses its own discharge channel to achieve passive balancing of the battery pack under test.

[0011] Preferably, each of the power supply battery strings is connected to the power supply path through a power supply selection module. Each battery cell in each row of the battery pack under test is connected to the input terminals of all selectors in the corresponding row of the multiplexer module. The output terminals of all selectors in each row of the multiplexer module are connected together and connected to the input terminal of the analog front-end sampling chip (AFE). The output terminal of the analog front-end sampling chip (AFE) is connected to the controller MCU.

[0012] The power supply selection module is connected to the controller MCU, all selectors in the multiplexer module are connected to the controller MCU, and the analog front-end sampling chip AFE is connected to the controller MCU.

[0013] The battery pack under test consists of multiple power supply batteries connected in series and parallel. Each power supply battery string consists of multiple battery cells connected in series. The battery pack under test consists of multiple battery cells forming a battery cell array. The multiplexer module consists of multiple selectors forming a selector array.

[0014] Preferably, the battery pack under test is composed of a first power supply battery string, a second power supply battery string, a third power supply battery string, and a fourth power supply battery string connected in parallel. The first power supply battery string is composed of batteries C11, C21, C31, and C41 connected in series. The second power supply battery string is composed of batteries C12, C22, C32, and C42 connected in series. The third power supply battery string is composed of batteries C13, C23, C33, and C43 connected in series. The fourth power supply battery string is composed of batteries C14, C24, C34, and C44 connected in series.

[0015] The power supply selection module includes switches M1, M2, M3, and M4. The gates of switches M1, M2, M3, and M4 are all connected to the controller MCU. The drains of switches M1, M2, M3, and M4 are all connected to the power supply path. The sources of switches M1, M2, M3, and M4 are respectively connected to the positive terminals of batteries C41, C42, C43, and C44. The negative terminals of batteries C11, C12, C13, and C14 are all grounded.

[0016] Preferably, the multiplexer module includes selectors PC11, PC12, PC13, PC14, PC21, PC22, PC23, PC24, PC31, PC32, PC33, PC34, PC41, PC42, PC43, and PC44, and all selectors in the multiplexer module are connected to the controller MCU.

[0017] The input terminals of selectors PC11, PC12, PC13, and PC14 are all connected to batteries C11, C12, C13, and C14, respectively. The output terminals of selectors PC11, PC12, PC13, and PC14 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap1.

[0018] The input terminals of selectors PC21, PC22, PC23, and PC24 are all connected to batteries C21, C22, C23, and C24, respectively. The output terminals of selectors PC21, PC22, PC23, and PC24 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap2.

[0019] The input terminals of selectors PC31, PC32, PC33, and PC34 are all connected to batteries C31, C32, C33, and C34, respectively. The output terminals of selectors PC31, PC32, PC33, and PC34 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap3.

[0020] The input terminals of selectors PC41, PC42, PC43, and PC44 are all connected to batteries C41, C42, C43, and C44, respectively. The output terminals of selectors PC41, PC42, PC43, and PC44 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through a filter capacitor cap4.

[0021] Preferably, each selector in the multiplexer module has four channels. When the selector receives an external signal 00 from the controller MCU, it selects the first channel; when the selector receives an external signal 01 from the controller MCU, it selects the second channel; when the selector receives an external signal 10 from the controller MCU, it selects the third channel; and when the selector receives an external signal 11 from the controller MCU, it selects the fourth channel.

[0022] Preferably, the analog front-end sampling chip (AFE) and the controller MCU communicate via SPI or CAN protocol according to their operating characteristics. The controller MCU receives the battery voltage signal sent by the analog front-end sampling chip (AFE) and performs calculations to detect the battery voltage.

[0023] (III) Beneficial Effects

[0024] Compared with the prior art, the multi-channel battery voltage detection circuit with equalization function provided by this utility model can not only detect the battery voltage of each battery cell in the power supply battery string, but also detect the battery voltage of multiple battery cells in different power supply battery strings at the same time. In addition, this circuit has a built-in battery pack equalization function, which can achieve effective equalization between different power supply battery strings. Furthermore, this circuit has strong scalability, which makes it easy to expand the scale of the battery pack under test. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a circuit diagram of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0028] A multi-channel battery voltage detection circuit with equalization function includes a battery pack under test, a power supply selection module, a multiplexer module, an analog front-end sampling chip (AFE), and a controller MCU.

[0029] The power supply selection module is connected to the battery pack under test and selects the battery string in the power supply path under the control of the controller MCU.

[0030] The multiplexer module is connected between the battery pack under test and the analog front-end sampling chip (AFE). Under the control of the controller MCU, it transmits the battery voltage signal to the analog front-end sampling chip (AFE) by selecting the corresponding channel. At the same time, it performs passive and active equalization on the battery pack under test by selecting the corresponding channel.

[0031] The analog front-end sampling chip (AFE) is connected between the multiplexer module and the controller MCU. It sends the battery voltage signal to the controller MCU to realize battery voltage detection. At the same time, under the control of the controller MCU, it uses its own discharge channel to achieve passive balancing of the battery pack under test.

[0032] Each battery string is connected to the power supply path through the power supply selection module. Each battery cell in each row of the battery pack under test is connected to the input of all selectors in the corresponding row of the multiplexer module. The outputs of all selectors in each row of the multiplexer module are connected together and connected to the input of the analog front-end sampling chip (AFE). The output of the analog front-end sampling chip (AFE) is connected to the controller MCU.

[0033] The power supply selection module is connected to the controller MCU, all selectors in the multiplexer module are connected to the controller MCU, and the analog front-end sampling chip AFE is connected to the controller MCU.

[0034] The battery pack under test consists of multiple power supply batteries connected in series and parallel. Each power supply battery string consists of multiple battery cells connected in series. The battery pack under test consists of multiple battery cells forming a battery cell array. The multiplexer module consists of multiple selectors forming a selector array.

[0035] The analog front-end sampling chip (AFE) and the controller MCU communicate via either SPI or CAN protocol, depending on their operating characteristics. The controller MCU receives the battery voltage signal sent by the analog front-end sampling chip (AFE) and performs calculations to detect the battery voltage.

[0036] like Figure 1 As shown, the battery pack under test consists of a first power supply battery string, a second power supply battery string, a third power supply battery string, and a fourth power supply battery string connected in parallel. The first power supply battery string consists of batteries C11, C21, C31, and C41 connected in series. The second power supply battery string consists of batteries C12, C22, C32, and C42 connected in series. The third power supply battery string consists of batteries C13, C23, C33, and C43 connected in series. The fourth power supply battery string consists of batteries C14, C24, C34, and C44 connected in series.

[0037] The power supply selection module includes switches M1, M2, M3, and M4. The gates of switches M1, M2, M3, and M4 are all connected to the controller MCU. The drains of switches M1, M2, M3, and M4 are all connected to the power supply path. The sources of switches M1, M2, M3, and M4 are connected to the positive terminals of batteries C41, C42, C43, and C44, respectively. The negative terminals of batteries C11, C12, C13, and C14 are all grounded.

[0038] The multiplexer module includes selectors PC11, PC12, PC13, PC14, PC21, PC22, PC23, PC24, PC31, PC32, PC33, PC34, PC41, PC42, PC43, and PC44. All selectors in the multiplexer module are connected to the controller MCU.

[0039] The input terminals of selectors PC11, PC12, PC13, and PC14 are all connected to batteries C11, C12, C13, and C14. The output terminals of selectors PC11, PC12, PC13, and PC14 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap1 (which has a filtering function and stabilizes voltage fluctuations).

[0040] The input terminals of selectors PC21, PC22, PC23, and PC24 are all connected to batteries C21, C22, C23, and C24, respectively. The output terminals of selectors PC21, PC22, PC23, and PC24 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap2 (which has a filtering function to stabilize voltage fluctuations).

[0041] The input terminals of selectors PC31, PC32, PC33, and PC34 are all connected to batteries C31, C32, C33, and C34, respectively. The output terminals of selectors PC31, PC32, PC33, and PC34 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap3 (which has a filtering function and stabilizes voltage fluctuations).

[0042] The input terminals of selectors PC41, PC42, PC43, and PC44 are all connected to batteries C41, C42, C43, and C44, respectively. The output terminals of selectors PC41, PC42, PC43, and PC44 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through a filter capacitor cap4 (which has a filtering function to stabilize voltage fluctuations).

[0043] Each selector in the multiplexer module has four channels. When the selector receives an external signal of 00 from the controller MCU, it selects the first channel; when the selector receives an external signal of 01 from the controller MCU, it selects the second channel; when the selector receives an external signal of 10 from the controller MCU, it selects the third channel; and when the selector receives an external signal of 11 from the controller MCU, it selects the fourth channel.

[0044] It is worth noting that, Figure 1The paper only provides one circuit configuration that can achieve the technical objectives of this application. The size of the battery pack under test and the multiplexer module can be adjusted as needed, for example, the multiplexer module can be changed from a 4*4 multiplexer array to a 4*2 multiplexer array.

[0045] To better illustrate the technical solution of this application, the working process of the technical solution of this application will be described in detail below with reference to several functional implementations:

[0046] 1) Perform battery voltage detection on battery C41.

[0047] The controller MCU sends external signals X0X1=00 to selector PC41, X8X9=00 to selector PC42, X16X17=00 to selector PC43, and X24X25=00 to selector PC44, so that selector PC41 / PC42 / PC43 / PC44 select the first channel, and connect the positive and negative terminals of battery C41 to the voltage measurement terminals of analog front-end sampling chip AFE through B4+ and B4- respectively;

[0048] Since the voltage measurement endpoints of the analog front-end sampling chip (AFE) are in a high-impedance state, the resistance of the selector's selection channel is small (usually 0.1 to 1 Ω), and the input current in measurement mode is extremely small (usually a few microamps or even less). Therefore, the voltage error introduced by the resistance of the selector's selection channel can be ignored.

[0049] 2) Simultaneously perform battery voltage detection on batteries C11, C22, C33, and C44.

[0050] The controller MCU sends external signals X0X1 / X8X9 / X16X17 / X24X25=11 to selectors PC41, PC42, PC43, and PC44, so that selectors PC41 / PC42 / PC43 / PC44 select the fourth channel, and connect the positive and negative terminals of battery C44 to the voltage measurement terminals of analog front-end sampling chip AFE through B4+ and B4- respectively.

[0051] The controller MCU sends an external signal X2X3 / X10X11 / X18X19 / X26X27=10 to selectors PC31, PC32, PC33, and PC34, so that selectors PC31 / PC32 / PC33 / PC34 select the third channel, and connect the positive and negative terminals of battery C33 to the voltage measurement terminals of analog front-end sampling chip AFE through B3+ and B3- respectively;

[0052] The controller MCU sends external signals X4X5 / X12X13 / X20X21 / X28X29=01 to selectors PC21, PC22, PC23, and PC24, so that selectors PC21 / PC22 / PC23 / PC24 select the second channel, and connect the positive and negative terminals of battery C22 to the voltage measurement terminals of analog front-end sampling chip AFE through B2+ and B2- respectively;

[0053] The controller MCU sends external signals X6X7 / X14X15 / X22X23 / X20X31=00 to selectors PC11, PC12, PC13, and PC14, so that selectors PC11 / PC12 / PC13 / PC14 select the first channel, and connect the positive and negative terminals of battery C11 to the voltage measurement terminals of analog front-end sampling chip AFE through B1+ and B1- respectively.

[0054] In addition to the battery cell combinations mentioned above, it can also detect the battery voltage of other complex battery cell combinations, thereby meeting the complex and ever-changing battery testing needs.

[0055] 3) Perform passive balancing on battery C44

[0056] When the voltage of battery C44 is too high, voltage balancing can be achieved by discharging it. First, the controller MCU sends an external signal X0X1 / X8X9 / X16X17 / X24X25=11 to selectors PC41 / PC42 / PC43 / PC44, so that selectors PC41 / PC42 / PC43 / PC44 select the fourth channel, connecting the positive and negative terminals of battery C44 to the analog front-end sampling chip AFE through B4+ and B4- respectively. Then, the controller MCU controls the analog front-end sampling chip AFE to open the discharge channel between B4+ and B4- to passively balance battery C44.

[0057] The discharge current is determined by the voltage of battery C44 and the resistance of the discharge channel. Since the resistance of the selector channel is small (usually 0.1 to 1 Ω), the discharge current is mainly limited by the internal equalization capability of the analog front-end sampling chip AFE.

[0058] 4) Actively balance battery C42 using battery C41.

[0059] When the voltage of battery C42 is 4.2V and the voltage of battery C41 is 4.1V, voltage balancing can be achieved by charging battery C41. First, the controller MCU sends an external signal X0X1 / X8X9=00 to selectors PC41 and PC42, so that selectors PC41 / PC42 select the first channel and connect the positive and negative terminals of battery C41 to B4+ and B4- respectively.

[0060] Subsequently, the controller MCU sends an external signal X16X17 / X24X25=01 to selectors PC43 and PC44, enabling selectors PC43 / PC44 to select the second channel, connecting the positive and negative terminals of battery C42 to B4+ and B4- respectively. This connects the positive and negative terminals of battery C41 to the positive and negative terminals of C42 respectively, forming a charging circuit. Battery C42 then charges battery C41, thus actively balancing battery C42.

[0061] 5) Actively balance battery C41 using batteries C42, C43, and C44.

[0062] When the voltage of battery C41 is too high, voltage balancing can be achieved by charging batteries C42, C43, and C44. The controller MCU sends external signals X0X1=00, X8X9=01, X16X17=10, and X24X25=11 to selectors PC41, PC42, PC43, and PC44 respectively, so that selectors PC41, PC42, PC43, and PC44 select the first channel, the second channel, the third channel, and the fourth channel respectively. This connects the positive and negative terminals of batteries C41, C42, C43, and C44 to B4+ and B4- respectively, forming a charging circuit. Battery C41 charges batteries C42, C43, and C44 to actively balance battery C41.

[0063] As charging progresses, the voltage difference between the batteries continuously decreases, resulting in a decrease in charging current. The charging current is determined by the voltage difference, the battery's internal resistance, and the resistance of the selector's selection channel. The charging current can be changed by selecting different selectors.

[0064] In addition to the battery cell combinations mentioned above, active charging balancing of other complex battery cell combinations can also be achieved, such as one cell to two cells, two cells to one cell, two cells to two cells, etc. Specifically, this can be achieved by configuring external signals X0 to X31 through the controller MCU.

[0065] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A multi-channel battery voltage detection circuit with equalization function, characterized in that: This includes the battery pack under test, power selection module, multiplexer module, analog front-end sampling chip (AFE), and controller MCU; The power supply selection module is connected to the battery pack under test and selects the battery string in the power supply path under the control of the controller MCU. The multiplexer module is connected between the battery pack under test and the analog front-end sampling chip (AFE). Under the control of the controller MCU, it transmits the battery voltage signal to the analog front-end sampling chip (AFE) by selecting the corresponding channel. At the same time, it performs passive and active equalization on the battery pack under test by selecting the corresponding channel. The analog front-end sampling chip (AFE) is connected between the multiplexer module and the controller MCU. It sends the battery voltage signal to the controller MCU to realize battery voltage detection. At the same time, under the control of the controller MCU, it uses its own discharge channel to achieve passive balancing of the battery pack under test.

2. The multi-channel battery voltage detection circuit with equalization function according to claim 1, characterized in that: Each of the aforementioned battery strings is connected to the power supply path through a power supply selection module. Each battery cell in each row of the battery pack under test is connected to the input terminals of all selectors in the corresponding row of the multiplexer module. The output terminals of all selectors in each row of the multiplexer module are connected together and connected to the input terminal of the analog front-end sampling chip (AFE). The output terminal of the analog front-end sampling chip (AFE) is connected to the controller MCU. The power supply selection module is connected to the controller MCU, all selectors in the multiplexer module are connected to the controller MCU, and the analog front-end sampling chip AFE is connected to the controller MCU. The battery pack under test consists of multiple power supply batteries connected in series and parallel. Each power supply battery string consists of multiple battery cells connected in series. The battery pack under test consists of multiple battery cells forming a battery cell array. The multiplexer module consists of multiple selectors forming a selector array.

3. The multi-channel battery voltage detection circuit with equalization function according to claim 2, characterized in that: The battery pack under test is composed of a first power supply battery string, a second power supply battery string, a third power supply battery string, and a fourth power supply battery string connected in parallel. The first power supply battery string is composed of batteries C11, C21, C31, and C41 connected in series. The second power supply battery string is composed of batteries C12, C22, C32, and C42 connected in series. The third power supply battery string is composed of batteries C13, C23, C33, and C43 connected in series. The fourth power supply battery string is composed of batteries C14, C24, C34, and C44 connected in series. The power supply selection module includes switches M1, M2, M3, and M4. The gates of switches M1, M2, M3, and M4 are all connected to the controller MCU. The drains of switches M1, M2, M3, and M4 are all connected to the power supply path. The sources of switches M1, M2, M3, and M4 are respectively connected to the positive terminals of batteries C41, C42, C43, and C44. The negative terminals of batteries C11, C12, C13, and C14 are all grounded.

4. The multi-channel battery voltage detection circuit with equalization function according to claim 3, characterized in that: The multiplexer module includes selectors PC11, PC12, PC13, PC14, PC21, PC22, PC23, PC24, PC31, PC32, PC33, PC34, PC41, PC42, PC43, and PC44. All selectors in the multiplexer module are connected to the controller MCU. The input terminals of selectors PC11, PC12, PC13, and PC14 are all connected to batteries C11, C12, C13, and C14, respectively. The output terminals of selectors PC11, PC12, PC13, and PC14 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap1. The input terminals of selectors PC21, PC22, PC23, and PC24 are all connected to batteries C21, C22, C23, and C24, respectively. The output terminals of selectors PC21, PC22, PC23, and PC24 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap2. The input terminals of selectors PC31, PC32, PC33, and PC34 are all connected to batteries C31, C32, C33, and C34, respectively. The output terminals of selectors PC31, PC32, PC33, and PC34 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through the filter capacitor cap3. The input terminals of selectors PC41, PC42, PC43, and PC44 are all connected to batteries C41, C42, C43, and C44, respectively. The output terminals of selectors PC41, PC42, PC43, and PC44 are connected together and connected to the input terminal of the analog front-end sampling chip AFE through a filter capacitor cap4.

5. The multi-channel battery voltage detection circuit with equalization function according to claim 4, characterized in that: Each selector in the multiplexer module has four channels. When the selector receives an external signal 00 from the controller MCU, it selects the first channel. When the selector receives an external signal 01 from the controller MCU, it selects the second channel. When the selector receives an external signal 10 from the controller MCU, it selects the third channel. When the selector receives an external signal 11 from the controller MCU, it selects the fourth channel.

6. The multi-channel battery voltage detection circuit with equalization function according to claim 2, characterized in that: The analog front-end sampling chip (AFE) and the controller MCU communicate via either SPI or CAN protocol depending on their operating characteristics. The controller MCU receives the battery voltage signal sent by the analog front-end sampling chip (AFE) and performs calculations to detect the battery voltage.

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