Series battery voltage sampling circuit and battery pack

Abstract

The application provides a series battery voltage sampling circuit and a battery pack, which comprises a series battery pack and a voltage sampling subcircuit; in the series battery pack, a voltage sampling subcircuit is connected between each adjacent battery; each voltage sampling subcircuit comprises a control branch and a voltage forming branch; for each voltage sampling subcircuit, the voltage forming branch and one end of the control branch are connected to the series node, the other end is grounded, and the voltage forming branch is turned on when the control branch is turned on; a first cut-off device is arranged in the control branch, and a second cut-off device is arranged in the voltage forming branch; when the negative electrode of the series battery pack is disconnected from the ground, the first cut-off device and the second cut-off device are in the cut-off state, so as to block the control branch and the voltage forming branch to provide a discharge path for the battery. The safety of voltage sampling is improved, the self-discharge phenomenon of micro-discharge of the battery through the sampling path is prevented, and the stable operation of the multi-string battery system is ensured.

Description

Technical Field

[0001] This application relates to the field of energy storage battery technology, and in particular to a series battery voltage sampling circuit and battery pack. Background Technology

[0002] With the widespread application of portable electronic devices, electric vehicles, and energy storage systems, lithium-ion batteries, as the primary energy storage unit, are gradually evolving from single-cell configurations to multi-cell series assemblies to meet higher voltage and capacity requirements. In multi-cell battery systems, to ensure the safety and reliability of system operation, the voltage of each string of batteries needs to be sampled in real time for battery state assessment and equalization control.

[0003] In existing technologies, voltage divider networks combined with MOSFET switching structures are commonly used for voltage sampling. In a typical scheme, the microcontroller unit controls the MOSFET to conduct, converting the high battery potential into a voltage signal suitable for MCU acquisition through a voltage divider resistor. However, in this structure, the circuit ground is usually shared with the lowest battery potential, and there are multiple potential paths between the sampling circuit and the high battery potential. Once the system experiences abnormal conditions such as battery over-discharge, the lithium battery protection IC controls the ground MOSFET to disconnect, causing the sampling circuit to be in a floating state. At this time, the high-potential battery may form an unexpected discharge path through the voltage divider resistor, control MOSFET, and other components in the original sampling path. This affects battery life and equalization effect, may cause further over-discharge of the high-potential series batteries, and may even cause cell damage and safety hazards. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a series battery voltage sampling circuit and battery pack to improve voltage sampling safety, prevent the battery from continuously discharging through the sampling path and causing self-discharge, and ensure the stable operation of multi-cell battery systems.

[0005] In a first aspect, embodiments of this application provide a series battery voltage sampling circuit, including: a series battery pack and a voltage sampling sub-circuit; In the series-connected battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit, and each voltage sampling sub-circuit includes a control branch and a voltage forming branch; For each of the voltage sampling sub-circuits, one end of the voltage forming branch and one end of the control branch are connected to the series node, and the other end is grounded. The voltage forming branch is turned on along with the control branch. The control branch is provided with a first cutoff device, and the voltage forming branch is provided with a second cutoff device. When the negative terminal of the series battery pack is disconnected from the ground, the first cutoff device and the second cutoff device are in a cutoff state to block the control branch and the voltage forming branch from providing a discharge path for the battery.

[0006] In conjunction with the first aspect, the embodiments of this application provide a first possible implementation of the first aspect, wherein the control branch further includes a first switching transistor device; One end of the first cutoff device is connected to the series node, and the other end is connected to the first switching device; The first switching device is disposed between the first cut-off device and ground.

[0007] In conjunction with the first aspect, this application provides a second possible implementation of the first aspect, wherein the first cutoff device is a diode and the first switching device is a first MOSFET; The anode of the diode is connected to the series node, and the cathode of the diode is connected to the drain of the first MOS transistor. The source of the first MOSFET is grounded.

[0008] In conjunction with the first aspect, this application provides a third possible implementation of the first aspect, wherein the voltage forming branch further includes a second switching device and a voltage divider resistor group; The second switching device is connected between the series node and the second cutoff device; The second cutoff device is connected between the second switching device and the voltage divider resistor group; The voltage divider resistor group is connected between the second cutoff device and ground.

[0009] In conjunction with the first aspect, this application provides a fourth possible implementation of the first aspect, wherein the second switching device is a second MOS transistor and the second cut-off device is a third MOS transistor; The drain of the second MOS transistor is connected to the series node, the gate is connected to the end where the first cutoff device and the first switching device are connected, and the source is connected to the source of the third MOS transistor. The gate of the third MOS transistor is connected to the gate of the second MOS transistor, and the drain is connected to the voltage divider resistor group.

[0010] In conjunction with the first aspect, this application provides a fifth possible implementation of the first aspect, wherein the first MOS transistor is an N-channel MOS transistor.

[0011] In conjunction with the first aspect, this application provides a sixth possible implementation of the first aspect, wherein both the second MOS transistor and the third MOS transistor are P-channel MOS transistors.

[0012] In conjunction with the first aspect, embodiments of this application provide a seventh possible implementation of the first aspect, which further includes a microcontroller; The microcontroller is connected to the first switching device and the voltage forming branch, respectively. The microcontroller sends a control signal to the first switching device to trigger the first switching device to turn on, thereby triggering the voltage forming branch to turn on to form a sampling voltage; The microcontroller receives the sampled voltage from the voltage forming branch.

[0013] In conjunction with the first aspect, this application provides an eighth possible implementation of the first aspect, which further includes a battery protection chip and a third switching device; The third switching device is disposed between the negative terminal of the series battery pack and ground, and is connected to the battery protection chip; The battery protection chip triggers the third switching device to turn off when the battery is over-discharged, thereby disconnecting the negative terminal of the series battery pack from ground.

[0014] Secondly, embodiments of this application provide a battery pack including a battery voltage sampling circuit as described in any of the first aspects.

[0015] This application provides a series battery voltage sampling circuit and battery pack, including: a series battery pack and a voltage sampling sub-circuit; in the series battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit, and each voltage sampling sub-circuit includes a control branch and a voltage forming branch; for each voltage sampling sub-circuit, one end of the voltage forming branch and one end of the control branch are connected to the series node, and the other end is grounded, and the voltage forming branch conducts along with the control branch; the control branch is provided with a first cutoff device, and the voltage forming branch is provided with a second cutoff device. When the negative terminal of the series battery pack is disconnected from ground, the first cutoff device and the second cutoff device are in a cutoff state, thereby blocking the control branch and the voltage forming branch from providing a discharge path for the battery. This improves the safety of voltage sampling, prevents the battery from continuously undergoing micro-discharge self-discharge through the sampling path, and ensures the stable operation of the multi-cell battery system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is one of the structural schematic diagrams of a series battery voltage sampling circuit provided in an embodiment of the present utility model; Figure 2 A second schematic diagram of a series battery voltage sampling circuit provided for an embodiment of this utility model; Figure 3 A third schematic diagram of a series battery voltage sampling circuit provided for an embodiment of this utility model; Figure 4 The fourth schematic diagram of a series battery voltage sampling circuit provided in this embodiment of the present invention. Detailed Implementation

[0018] 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 embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0023] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] In existing technologies, voltage divider networks combined with MOSFET switching structures are commonly used for voltage sampling. In a typical scheme, the microcontroller unit (MCU) controls the MOSFET to conduct, converting the battery's high potential into a voltage signal suitable for MCU acquisition via a voltage divider resistor. However, in this structure, the circuit ground is usually shared with the battery's lowest potential, and multiple potential paths exist between the sampling circuit and the battery's high potential. If the system experiences abnormal conditions such as battery over-discharge, the lithium battery protection IC controls the ground MOSFET to disconnect, causing the sampling circuit to be in a floating state. At this time, the high-potential battery may form an unintended discharge path through the voltage divider resistor and control MOSFET in the original sampling path. This affects battery life and balancing performance, potentially causing further over-discharge of the high-potential series batteries, and even leading to cell damage and safety hazards.

[0025] This application provides a series battery voltage sampling circuit and battery pack, including: a series battery pack and a voltage sampling sub-circuit; in the series battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit, and each voltage sampling sub-circuit includes a control branch and a voltage forming branch; for each voltage sampling sub-circuit, one end of the voltage forming branch and one end of the control branch are connected to the series node, and the other end is grounded, and the voltage forming branch conducts along with the control branch; the control branch is provided with a first cutoff device, and the voltage forming branch is provided with a second cutoff device. When the negative terminal of the series battery pack is disconnected from ground, the first cutoff device and the second cutoff device are in a cutoff state, thereby blocking the control branch and the voltage forming branch from providing a discharge path for the battery. This improves the safety of voltage sampling, prevents the battery from continuously undergoing micro-discharge self-discharge through the sampling path, and ensures the stable operation of the multi-cell battery system.

[0026] Please see Figure 1 , Figure 1 This is one of the structural schematic diagrams of a series battery voltage sampling circuit provided in this embodiment.

[0027] like Figure 1 As shown in the figure, the series battery voltage sampling circuit provided in this embodiment includes: a series battery pack and a voltage sampling sub-circuit.

[0028] Specifically, in the series-connected battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit. Each voltage sampling sub-circuit includes a control branch and a voltage forming branch. For each voltage sampling sub-circuit, one end of the voltage forming branch and the control branch are connected to the series node, and the other end is grounded. The voltage forming branch conducts when the control branch is turned on. A first cutoff device is provided in the control branch, and a second cutoff device is provided in the voltage forming branch. When the negative terminal of the series-connected battery pack is disconnected from ground, the first and second cutoff devices are in the cutoff state to block the control branch and the voltage forming branch from providing a discharge path for the battery.

[0029] In practical implementation, in a series-connected battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit for sampling the voltage at that node, which is then processed and analyzed by the microcontroller unit (MCU). The number of voltage sampling sub-circuits corresponds to the number of battery strings, and each voltage sampling sub-circuit has the same structure.

[0030] Here, each voltage sampling subcircuit includes a control branch and a voltage forming branch. One end of both the control branch and the voltage forming branch is connected to the series node of the adjacent battery, and the other end is connected to the common ground.

[0031] The conduction state of the voltage forming branch is controlled by the conduction state of the control branch. That is, when the control branch is on, the voltage forming branch is also on, thus enabling voltage sampling of the target node.

[0032] Specifically, the control branch has a first cutoff device, and the voltage forming branch has a second cutoff device. Under normal operating conditions, the control branch is turned on by the MCU, thereby closing the voltage forming branch and realizing the voltage division sampling process. However, in certain special cases, such as when the lithium battery protection IC controls the disconnection of the battery negative terminal from the ground wire, to prevent the high-potential series node from forming an unexpected leakage discharge path through the sampling sub-circuit, the first and second cutoff devices simultaneously enter the cutoff state, effectively blocking any possible current path in the control branch and the voltage forming branch, thereby preventing the sampling channel from forming a leakage discharge path for the battery.

[0033] This allows for automatic isolation during critical power outages while ensuring normal voltage sampling accuracy, greatly improving the safety and reliability of the voltage sampling circuit for multi-cell lithium battery packs.

[0034] As one possible implementation method, please refer to Figure 2 , Figure 1 This is a second schematic diagram of a series battery voltage sampling circuit provided in this embodiment. Figure 2 As shown, the control branch also includes a first switching device, and the voltage forming branch also includes a second switching device and a voltage divider resistor group.

[0035] Specifically, one end of the first cutoff device is connected to the series node, and the other end is connected to the first switching device; the first switching device is positioned between the first cutoff device and ground. The second switching device is connected between the series node and the second cutoff device; the second cutoff device is connected between the second switching device and the voltage divider resistor group; the voltage divider resistor group is connected between the second cutoff device and ground.

[0036] In a further embodiment, the control branch includes a first cut-off device and a first switching device. One end of the first cut-off device is connected to the corresponding battery series node, and the other end of the first cut-off device is connected to the first switching device. The first switching device is located between the first cut-off device and the ground wire. That is, the current path in the control branch is as follows: battery series node → first cut-off device → first switching device → ground. By controlling the on / off state of the first switching device, the control of the first cut-off device circuit is realized.

[0037] Furthermore, the voltage forming branch includes a second switching device, a second cutoff device, and a voltage divider resistor group. The second switching device is connected between the battery series node and the second cutoff device, the second cutoff device is connected between the second switching device and the voltage divider resistor group, and the voltage divider resistor group is located between the second cutoff device and the ground wire, forming a standard voltage divider sampling structure. That is, the current path of the voltage forming branch is as follows: battery series node → second switching device → second cutoff device → voltage divider resistor group → ground.

[0038] Under normal operating conditions, the first switching device conducts, activating the control branch. This, in turn, enables the second switching device to conduct via control logic, thereby closing the voltage forming branch and completing sampling. When a battery pack malfunctions (such as the lithium battery protection IC disconnecting the negative terminal from ground), the control circuit shuts down both the first and second cutoff devices, disconnecting the voltage forming branch. This effectively prevents current from leaking from the high-potential node to the low-potential node, avoiding over-discharge of the battery.

[0039] In a specific implementation, the first cutoff device is a diode D1, and the first switching device is a first MOSFET M1; the anode of the diode is connected to a series node, and the cathode of the diode is connected to the drain of the first MOSFET M1; the source of the first MOSFET M1 is grounded. The second switching device is a second MOSFET M2, and the second cutoff device is a third MOSFET M3; the drain of the second MOSFET M2 is connected to a series node, the gate is connected to the end where the first cutoff device and the first switching device (first MOSFET M1) are connected, and the source is connected to the source of the third MOSFET M3; the gate of the third MOSFET M3 is connected to the gate of the second MOSFET M2, and the drain is connected to a voltage divider resistor group.

[0040] In a preferred embodiment, each voltage sampling subcircuit includes a control branch and a voltage forming branch. The control branch includes a first cutoff device and a first switching device. The anode of the first switching device is connected to the series node of an adjacent battery, and the cathode is connected to the drain of a first MOSFET M1. The source of the first MOSFET M1 is grounded, and its gate is connected to the control pin of a microcontroller unit (MCU) to control its conduction. The path of this structure is: series node → diode D1 → first MOSFET M1 → GND, used to control the establishment and isolation of the conduction state signal. The voltage forming branch includes a second switching device, a second cutoff device, and a voltage divider resistor group. The second switching device is a second MOSFET M2, whose drain is connected to the series node, and its source is connected to the source of a third MOSFET M3. The third MOSFET M3 is a second cutoff device, and its drain is connected to the voltage divider resistor group used for voltage sampling. The other end of the voltage divider resistor group is grounded. The gates of the second MOSFET M2 and the third MOSFET M3 are both connected to the cathode of diode D1, i.e., connected between the first cutoff device and the first MOSFET M1.

[0041] In the circuit's on-state, after the first MOSFET M1 is turned on, it pulls down the gate of the second MOSFET M2, causing M2 to turn on. This forms the following voltage sampling path: battery series node → second MOSFET M2 (drain-source) → third MOSFET M3 (source-drain) → voltage divider resistor group → ground, achieving voltage division sampling. When an abnormal disconnection occurs in the system, such as when the lithium battery protection IC disconnects the ground line (GND is floating), diode D1 is turned off, and the third MOSFET M3 is turned off, automatically cutting off this voltage divider sampling branch. This prevents high potential from continuously discharging to the lower-level cells through the sampling path, protecting the battery from over-discharge damage.

[0042] Preferably, the first MOSFET M1 is an N-channel MOSFET, and the second MOSFET M2 and the third MOSFET M3 are both P-channel MOSFETs. The voltage divider resistor group includes a first voltage divider resistor R1 and a second voltage divider resistor R2, which are connected in series. The connection node between the first voltage divider resistor R1 and the second voltage divider resistor R2 serves as the voltage sampling point for acquiring the sampled voltage.

[0043] As one possible implementation method, please refer to Figure 3 , Figure 3 This is the third schematic diagram of a series battery voltage sampling circuit provided in this embodiment. Figure 3 As shown, the first switching device can also be a first transistor Q1, the second switching device can be a second transistor Q2, and the second cut-off device can be a third transistor Q3.

[0044] Specifically, the emitter of the first transistor Q1 is connected to the cathode of the diode D1, the base receives the control signal from the MCU, and the collector is grounded; the base of the second transistor Q2 is connected to the cathode of the diode D1, the emitter is connected to the series node between adjacent batteries in the series battery pack, the collector is connected to the collector of the third transistor Q3, the base of the third transistor Q3 is connected to the base of the second transistor Q2, and the emitter is connected to a voltage divider resistor group.

[0045] It should be noted that the operation of the first transistor Q1, the second transistor Q2, and the third transistor Q3 is the same as that of the first MOSFET M1, the second MOSFET M2, and the third MOSFET M3 described above, and will not be repeated here.

[0046] As one possible implementation method, please refer to Figure 4 , Figure 4 This is the fourth schematic diagram of a series battery voltage sampling circuit provided in this embodiment. Figure 4As shown, the series battery voltage sampling circuit also includes a microcontroller, a battery protection chip, and a third switching device, which can be a fourth MOSFET M4.

[0047] Specifically, the microcontroller is connected to the first switching device (first MOSFET M1) and the voltage forming branch. The microcontroller sends a control signal to the first switching device (first MOSFET M1) to trigger it to turn on, which in turn triggers the voltage forming branch to turn on and form a sampling voltage. The microcontroller receives the sampling voltage from the voltage forming branch. The third switching device (fourth MOSFET M4) is located between the negative terminal of the series battery pack and ground and is connected to the battery protection chip. When the battery is over-discharged, the battery protection chip triggers the third switching device to turn off, thereby disconnecting the negative terminal of the series battery pack from ground.

[0048] Here, the connection node between the first voltage divider resistor R1 and the second voltage divider resistor R2 of the microcontroller is used to acquire the sampling voltage. The gate of the fourth MOSFET M4 is connected to the battery protection chip, and the source is connected to the negative terminal of the series battery pack.

[0049] In a further embodiment, the microcontroller outputs a control signal to the gate of the first MOSFET M1 to control its conduction state. When the microcontroller outputs a high-level control signal to the first MOSFET M1, the first MOSFET M1 conducts, closing the control branch. After the control branch is turned on, the second MOSFET M2 and the third MOSFET M3 are turned on, and the voltage forming branch is turned on accordingly, forming a voltage sampling path. The microcontroller connects to the voltage divider point in the voltage forming branch through its sampling input port, thereby receiving the sampling voltage signal corresponding to the series node.

[0050] Furthermore, to prevent the sampling branch current from still having a discharge path under over-discharge conditions, a third switching device, namely the fourth MOSFET M4, is installed between the negative terminal of the series battery pack and ground. The fourth MOSFET M4 is connected to the battery protection chip and is used to control the ground connection status in real time according to the battery status: when the battery is in a normal state, the battery protection chip keeps the fourth MOSFET M4 on, and the negative terminal of the battery is connected to the system ground; when an over-discharge condition is detected, the battery protection chip triggers the fourth MOSFET M4 to turn off, thereby disconnecting the negative terminal of the series battery pack from ground.

[0051] At this time, the second MOSFET M2 and the third MOSFET M3 cannot maintain conduction, and the entire voltage sampling branch is in the cut-off state, thereby avoiding the problem of the battery continuing to discharge through the sampling channel under the protection state, and further ensuring the safe operation of the battery pack.

[0052] Furthermore, this embodiment also provides a battery pack, including as follows: Figures 1-4 The series battery voltage sampling circuit shown in the figure.

[0053] This application provides a series battery voltage sampling circuit and battery pack, including: a series battery pack and a voltage sampling sub-circuit; in the series battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit, and each voltage sampling sub-circuit includes a control branch and a voltage forming branch; for each voltage sampling sub-circuit, one end of the voltage forming branch and one end of the control branch are connected to the series node, and the other end is grounded, and the voltage forming branch conducts along with the control branch; the control branch is provided with a first cutoff device, and the voltage forming branch is provided with a second cutoff device. When the negative terminal of the series battery pack is disconnected from ground, the first cutoff device and the second cutoff device are in a cutoff state, thereby blocking the control branch and the voltage forming branch from providing a discharge path for the battery. This improves voltage sampling safety, prevents the battery from continuously undergoing micro-discharge self-discharge through the sampling path, and ensures the stable operation of the multi-cell battery system.

[0054] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A series battery voltage sampling circuit, characterized in that, include: Series-connected battery pack and voltage sampling sub-circuit; In the series battery pack, each series node between adjacent batteries is connected to a voltage sampling sub-circuit, and each voltage sampling sub-circuit includes a control branch and a voltage forming branch. For each of the voltage sampling sub-circuits, one end of the voltage forming branch and one end of the control branch are connected to the series node, and the other end is grounded. The voltage forming branch is turned on along with the control branch. The control branch is provided with a first cutoff device, and the voltage forming branch is provided with a second cutoff device. When the negative terminal of the series battery pack is disconnected from the ground, the first cutoff device and the second cutoff device are in a cutoff state to block the control branch and the voltage forming branch from providing a discharge path for the battery.

2. The series battery voltage sampling circuit according to claim 1, characterized in that, The control branch also includes a first switching transistor device; One end of the first cutoff device is connected to the series node, and the other end is connected to the first switching device; The first switching device is disposed between the first cut-off device and ground.

3. The series battery voltage sampling circuit according to claim 2, characterized in that, The first cutoff device is a diode, and the first switching device is a first MOSFET; The anode of the diode is connected to the series node, and the cathode of the diode is connected to the drain of the first MOS transistor. The source of the first MOSFET is grounded.

4. The series battery voltage sampling circuit according to claim 2, characterized in that, The voltage forming branch also includes a second switching device and a voltage divider resistor group; The second switching device is connected between the series node and the second cutoff device; The second cutoff device is connected between the second switching device and the voltage divider resistor group; The voltage divider resistor group is connected between the second cutoff device and ground.

5. The series battery voltage sampling circuit according to claim 4, characterized in that, The second switching device is a second MOSFET, and the second cut-off device is a third MOSFET; The drain of the second MOS transistor is connected to the series node, the gate is connected to the end where the first cutoff device and the first switching device are connected, and the source is connected to the source of the third MOS transistor. The gate of the third MOS transistor is connected to the gate of the second MOS transistor, and the drain is connected to the voltage divider resistor group.

6. The series battery voltage sampling circuit according to claim 3, characterized in that: The first MOSFET is an N-channel MOSFET.

7. The series battery voltage sampling circuit according to claim 5, characterized in that... ； Both the second MOS transistor and the third MOS transistor are P-channel MOS transistors.

8. The series battery voltage sampling circuit according to claim 2, characterized in that, It also includes microcontrollers; The microcontroller is connected to the first switching device and the voltage forming branch, respectively. The microcontroller sends a control signal to the first switching device to trigger the first switching device to turn on, thereby triggering the voltage forming branch to turn on to form a sampling voltage; The microcontroller receives the sampled voltage from the voltage forming branch.

9. The series battery voltage sampling circuit according to claim 1, characterized in that, It also includes battery protection chips and third switching devices; The third switching device is disposed between the negative terminal of the series battery pack and ground, and is connected to the battery protection chip; The battery protection chip triggers the third switching device to turn off when the battery is over-discharged, thereby disconnecting the negative terminal of the series battery pack from ground.

10. A battery pack, characterized in that, Includes the series battery voltage sampling circuit as described in any one of claims 1-9.

Images