A charge and discharge protection circuit and energy storage device

Abstract

The application discloses a charging and discharging protection circuit and an energy storage device, and relates to the technical field of charging and discharging protection. The charging and discharging protection circuit comprises an overcharging voltage end, an overdischarging voltage end, a charger detection end, a sampling end, a first switching unit, a second switching unit and a third switching unit. The overcharging voltage end is electrically connected with the control end of the third switching unit through the first switching unit. The overdischarging voltage end is electrically connected with the control end of the third switching unit. The control end of the first switching unit and the control end of the third switching unit are both connected with a first fixed voltage end through the second switching unit. The control end of the second switching unit is electrically connected with the charger detection end. The sampling end is connected with a second fixed voltage end through the third switching unit. The above technical scheme can solve the problems that overcharging cannot be discharged and overdischarging cannot be charged.

Description

Technical Field

[0001] This application relates to the field of charge and discharge protection technology, and in particular to a charge and discharge protection circuit and an energy storage device. Background Technology

[0002] Existing charge and discharge protection circuits will stop charging when they detect that the battery pack is overcharged, and stop discharging when they detect that the battery pack is over-discharged.

[0003] However, if an overcharge state is detected but cannot be cleared, the battery pack will be fully charged but unable to discharge normally; if an over-discharge state is detected but cannot be cleared, the battery pack will be depleted but unable to charge normally. Summary of the Invention

[0004] This application provides a charge / discharge protection circuit and an energy storage device to solve the problems of being unable to discharge due to overcharging and being unable to charge due to over-discharging.

[0005] According to one aspect of this application, a charge-discharge protection circuit is provided, comprising: an overcharge voltage terminal, an over-discharge voltage terminal, a charger detection terminal, a sampling terminal, a first switching unit, a second switching unit, and a third switching unit; The overcharge voltage terminal is electrically connected to the control terminal of the third switch unit through the first switch unit, and the overdischarge voltage terminal is electrically connected to the control terminal of the third switch unit; Both the control terminal of the first switch unit and the control terminal of the third switch unit are connected to the first fixed voltage terminal through the second switch unit, and the control terminal of the second switch unit is electrically connected to the charger detection terminal. The sampling terminal is connected to the second fixed voltage terminal through the third switching unit; The overcharge voltage terminal and the over-discharge voltage terminal jointly control the on / off state of the third switching unit, and the charger detection terminal controls the on / off state of the second switching unit to selectively enable the overcharge voltage terminal to control the third switching unit.

[0006] Optionally, the charge / discharge protection circuit is applied to an energy storage device; The charger detection terminal is configured such that when the energy storage device is connected to a charger, the potential of the charger detection terminal is the enable level of the second switching unit, and when the energy storage device is not connected to a charger, the potential of the charger detection terminal is the disable level of the second switching unit.

[0007] Optionally, the charge / discharge protection circuit is applied to an energy storage device, which includes a battery pack; The overcharge voltage terminal is configured such that when the battery pack is overcharged, the potential of the overcharge voltage terminal is the disabled level of the third switching unit, and when the battery pack is not overcharged, the potential of the overcharge voltage terminal is the enabled level of the third switching unit. The over-discharge voltage terminal is configured such that when the battery pack is over-discharged, the potential of the over-discharge voltage terminal is the disabled level of the third switching unit, and when the battery pack is not over-discharged, the potential of the over-discharge voltage terminal is the enabled level of the third switching unit.

[0008] Optionally, the potential of the first fixed voltage terminal is the enable level of the first switching unit and the disable level of the third switching unit.

[0009] Optionally, the first switching unit includes a first transistor, and the third switching unit includes a third transistor; The first terminal of the first transistor is electrically connected to the overcharge voltage terminal, the second terminal of the first transistor is electrically connected to the gate of the third transistor, and the gate of the first transistor is electrically connected to the first fixed voltage terminal through the second switching unit; the first terminal of the third transistor is electrically connected to the sampling terminal, and the second terminal of the third transistor is electrically connected to the second fixed voltage terminal. Wherein, the first fixed voltage terminal is a ground terminal, the first transistor is a P-type transistor, and the third transistor is an N-type transistor.

[0010] Optionally, it also includes: a first diode, a second diode, and a third diode; The anode of the first diode is electrically connected to the second electrode of the first transistor, and the cathode of the first diode is electrically connected to the gate of the third transistor at the first node; The anode of the second diode is electrically connected to the over-discharge voltage terminal, and the cathode of the second diode is electrically connected to the gate of the third transistor at the first node; The anode of the third diode is electrically connected to the over-discharge voltage terminal, and the cathode of the third diode is electrically connected to the ground terminal through the second switching unit.

[0011] Optionally, it may also include: a first voltage divider resistor and a second voltage divider resistor; The first voltage divider resistor is connected in series between the overcharge voltage terminal and the gate of the first transistor; The second voltage divider resistor is connected in series between the gate of the first transistor and the second switching unit.

[0012] Optionally, it also includes: a third voltage divider resistor and a fourth voltage divider resistor; The first end of the third voltage divider resistor is electrically connected to the second terminal of the first transistor at the first node, and the second end of the third voltage divider resistor is electrically connected to the gate of the third transistor. The fourth voltage divider resistor is connected in series between the gate of the third transistor and the second fixed voltage terminal, which is a ground terminal.

[0013] Optional features also include: a thermistor; The second fixed voltage terminal is the ground terminal; The sampling terminal is electrically connected to the ground terminal through the temperature-sensitive resistor and the third switching unit.

[0014] According to another aspect of this application, an energy storage device is provided, including: a charge and discharge protection circuit provided in any embodiment of this application.

[0015] The technical solution of this application, by setting a first switch unit, a second switch unit, and a third switch unit, can output a sampling result indicating whether charging or discharging is possible through a sampling terminal, thereby informing the charger or electrical device whether charging or discharging is possible. It can output a sampling signal normally when overcharged but not connected to a charger, and can also output a sampling signal normally when over-discharged but connected to a charger. In this way, the battery pack can discharge normally when overcharged and can charge normally when over-discharged, thus avoiding the inability to discharge normally when overcharged and the inability to charge normally when over-discharged.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the circuit structure of a charge / discharge protection circuit provided in an embodiment of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] As described in the background section, conventional charge / discharge protection circuits typically connect a charging MOSFET and a discharging MOSFET in series between the battery pack and the charge / discharge port. When the battery pack is overcharged, the charging MOSFET is turned off; when the battery pack is over-discharged, the discharging MOSFET is turned off. When the battery pack is overcharged, the charging MOSFET is turned off, and even if discharge can be achieved through the body diode of the charging MOSFET, it is only a temporary, small-current discharge, and the battery pack cannot discharge normally. Similarly, when the battery pack is over-discharged, the discharging MOSFET is turned off, and even if charging can be achieved through the body diode of the discharging MOSFET, it is only a temporary, small-current charging, and the battery pack cannot charge normally.

[0022] To address the aforementioned technical problems, this application provides a charge / discharge protection circuit, comprising: an overcharge voltage terminal, an over-discharge voltage terminal, a charger detection terminal, a sampling terminal, a first switching unit, a second switching unit, and a third switching unit. The overcharge voltage terminal is electrically connected to the control terminal of the third switching unit via the first switching unit, and the over-discharge voltage terminal is electrically connected to the control terminal of the third switching unit. The control terminals of both the first and third switching units are connected to a first fixed voltage terminal via the second switching unit, and the control terminal of the second switching unit is electrically connected to the charger detection terminal. The sampling terminal is connected to a second fixed voltage terminal via the third switching unit. The overcharge voltage terminal and the over-discharge voltage terminal jointly control the switching on and off of the third switching unit, and the charger detection terminal controls the switching on and off of the second switching unit to selectively enable the overcharge voltage terminal to control the third switching unit.

[0023] By adopting the above technical solution, and by setting up a first switch unit, a second switch unit, and a third switch unit, the sampling result of whether charging or discharging can be performed can be output through the sampling terminal to inform the charger or electrical device whether charging or discharging is possible. The sampling signal can be output normally when overcharged but not connected to the charger, and the sampling signal can be output normally when over-discharged but connected to the charger. In this way, the battery pack can discharge normally when overcharged and charge normally when over-discharged, thus avoiding the inability to discharge normally when overcharged and the inability to charge normally when over-discharged.

[0024] The above is the core idea of ​​this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0025] It should be noted that the implementation methods provided in this application can be combined with each other without contradiction.

[0026] Figure 1 This is a schematic diagram of the circuit structure of a charge / discharge protection circuit provided in an embodiment of this application. (Refer to...) Figure 1 The charge / discharge protection circuit includes an overcharge voltage terminal CO, an over-discharge voltage terminal DO, a charger detection terminal BS, a sampling terminal TV, a first switching unit 10, a second switching unit 20, and a third switching unit 30. The overcharge voltage terminal CO is electrically connected to the control terminal of the third switching unit 30 through the first switching unit 10, and the over-discharge voltage terminal DO is electrically connected to the control terminal of the third switching unit 30. The control terminals of the first switching unit 10 and the third switching unit 30 are both connected to the first fixed voltage terminal VG1 through the second switching unit 20, and the control terminal of the second switching unit 20 is electrically connected to the charger detection terminal BS. The sampling terminal TV is connected to the second fixed voltage terminal VG2 through the third switching unit 30. The overcharge voltage terminal CO and the over-discharge voltage terminal DO jointly control the on / off state of the third switching unit 30, and the charger detection terminal BS controls the on / off state of the second switching unit 20 to selectively enable the control of the third switching unit by the overcharge voltage terminal CO.

[0027] The circuit includes three terminals: an overcharge voltage terminal (CO) for transmitting overcharge signals (different potential levels indicate whether overcharging or over-discharging occurs), an over-discharge voltage terminal (DO) for transmitting over-discharge signals (different potential levels indicate whether over-discharging occurs), a charger detection terminal (BS) for transmitting charger detection signals (different potential levels indicate whether a charger is connected), and a sampling terminal (TV) for transmitting sampling signals (different potential levels or the presence or absence of an electrical signal indicate the sampling result of the charge / discharge protection circuit, thus transmitting the sampling result indicating whether charging or discharging is permissible). The first switching unit 10, the second switching unit 20, and the third switching unit 30 can, under the control of the control terminal, connect or disconnect the electrical signal transmission path between their first and second terminals. The first fixed voltage terminal (VG1) can transmit a first fixed potential signal, and the second fixed voltage terminal (VG2) can transmit a second fixed potential signal.

[0028] In some implementations, charge / discharge protection circuits are applied to energy storage devices ( Figure 1 (Not shown in the image) The energy storage device includes a battery pack and a battery management chip. The overcharge voltage terminal CO, the over-discharge voltage terminal DO, and the charger detection terminal BS can be electrically connected to the battery management chip.

[0029] In some implementations, the first fixed voltage terminal VG1 and / or the second fixed voltage terminal VG2 can be a power supply terminal or a ground terminal.

[0030] In some implementations, the sampling terminal TV can be connected to a charger or an electrical device. The charger can charge or stop charging based on different potential levels of the sampling terminal TV or the presence or absence of an electrical signal. The electrical device can discharge or stop discharging based on different potential levels of the sampling terminal TV or the presence or absence of an electrical signal.

[0031] For example, refer to Figure 1 The overcharge voltage terminal CO is connected in parallel with the overdischarge voltage terminal DO through the first switching unit 10 to the first node N1. The first node N1 is electrically connected to the control terminal of the third switching unit 30. The potential levels of the overcharge voltage terminal CO and the overdischarge voltage terminal DO can both affect the potential level of the control terminal of the third switching unit 30.

[0032] When the charger detection terminal BS controls the second switch unit 20 to be turned on, the potential level of the over-discharge voltage terminal DO can be kept roughly consistent with or the same as the potential level of the first fixed voltage terminal. The potential level of the first node N1 mainly depends on the potential level of the over-charge voltage terminal CO. That is, whether the third switch unit 30 is turned on mainly depends on whether the battery pack is overcharged.

[0033] When the charger detection terminal BS controls the second switch unit 20 to turn off, the potential level of the control terminal of the first switch unit 10 and the potential level of the first node N1 are related to the potential level of the over-discharge voltage terminal DO. The potential level of the first node N1 mainly depends on the potential level of the over-discharge voltage terminal DO, that is, whether the third switch unit 30 is turned on mainly depends on whether the battery pack is over-discharged.

[0034] When the third switch unit 30 is turned on, the sampling terminal TV can have a sampling signal; when the third switch unit 30 is turned off, the sampling terminal TV does not have a sampling signal.

[0035] In some implementations, the charge / discharge protection circuit is applied to the energy storage device. When the energy storage device is connected to a charger, the sampling terminal TV can be connected to the charger. If the battery pack in the energy storage device is not overcharged, the third switching unit 30 can be turned on regardless of whether the battery pack is over-discharged, allowing the sampling terminal TV to have a sampling signal. After receiving the sampling signal from the sampling terminal TV, the charger can open the charging circuit to charge the battery pack. If the battery pack in the energy storage device is overcharged, the third switching unit 30 is turned off, preventing the sampling terminal TV from having a sampling signal. The charger does not receive the sampling signal from the sampling terminal TV and therefore does not charge the battery pack.

[0036] In some implementations, the charge / discharge protection circuit is applied to the energy storage device. When the energy storage device is connected to the electrical device, the sampling terminal TV can be connected to the electrical device. If the battery pack in the energy storage device is not overcharged, the third switching unit 30 can be turned on regardless of whether the battery pack is overcharged, allowing the sampling terminal TV to have a sampling signal. After receiving the sampling signal from the sampling terminal TV, the electrical device can open the discharge circuit to discharge the battery pack. If the battery pack in the energy storage device is overcharged, the third switching unit 30 is turned off, preventing the sampling terminal TV from having a sampling signal. The electrical device does not receive the sampling terminal TV and therefore does not discharge the battery pack.

[0037] In other words, when the battery pack is overcharged, if a charger is connected, the third switch unit 30 is turned off, the sampling terminal TV has no sampling signal, and the battery pack does not charge. If a charger is not connected, for example, an electrical device can be connected, the third switch unit 30 is turned on, the sampling terminal TV has a sampling signal, and the battery pack can discharge. When the battery pack is over-discharged, if a charger is not connected, for example, an electrical device can be connected, the third switch unit 30 is turned off, the sampling terminal TV has no sampling signal, and the battery pack does not discharge. If a charger is connected, the third switch unit 30 is turned on, the sampling terminal TV has a sampling signal, and the battery pack can charge.

[0038] Compared to conventional charge / discharge protection circuits, the charge / discharge protection circuit in this embodiment utilizes the characteristics that the charger needs to receive a sampling signal before charging and the electrical device needs to receive a sampling signal before discharging to set up a third switching unit 30. Charge / discharge protection can be performed through the conduction state of the third switching unit 30. It is not necessary to control the charging MOSFET or discharging MOSFET between the battery pack and the charge / discharge port to turn off during overcharging or over-discharging. It can ensure that the normal discharge of the battery pack is not affected during overcharging and the normal charging of the battery pack is not affected during over-discharging. Furthermore, the conduction state of the third switching unit 30 is jointly controlled by the overcharge voltage terminal CO, the over-discharge voltage terminal DO, and the charger detection terminal BS. The sampling terminal TV can accurately output the sampling result of whether charging or discharging can be performed. This ensures that the sampling signal can be output normally when overcharging but not connected to the charger, and when over-discharging but connected to the charger, so as to avoid the inability to discharge normally when overcharging and the inability to charge normally when over-discharging.

[0039] The charge / discharge protection circuit provided in this application embodiment, by setting a first switch unit, a second switch unit, and a third switch unit, can output a sampling result indicating whether charging or discharging is possible through a sampling terminal, thereby informing the charger or electrical device whether charging or discharging is possible. It can output a sampling signal normally when overcharged but not connected to a charger, and can also output a sampling signal normally when over-discharged but connected to a charger. In this way, the battery pack can discharge normally when overcharged and can charge normally when over-discharged, thus avoiding the inability to discharge normally when overcharged and the inability to charge normally when over-discharged.

[0040] Optionally, the charge / discharge protection circuit also includes a thermistor NTC; the second fixed voltage terminal VG2 is the ground terminal GND; the sampling terminal TV is electrically connected to the ground terminal GND through the thermistor and the third switching unit 30. Thus, when the third switching unit 30 is turned on, the sampling terminal TV can output a temperature sampling signal; when the third switching unit 30 is turned off, the sampling terminal TV does not output a temperature sampling signal.

[0041] In an optional embodiment, the charger detection terminal BS is configured such that when the energy storage device is connected to the charger, the potential of the charger detection terminal BS is the enable level of the second switching unit 20, and when the energy storage device is not connected to the charger, the potential of the charger detection terminal BS is the disable level of the second switching unit 20.

[0042] In this embodiment, the enable level is the potential level that controls the switching unit to turn on, and the disable level is the potential level that controls the switching unit to turn off. In some embodiments, the enable level of the second switching unit 20 is high, and the disable level is low. When the energy storage device is connected to a charger, the charger detection terminal BS can be high to control the second switching unit 20 to turn on; when the energy storage device is not connected to a charger, the charger detection terminal BS can be low to control the second switching unit 20 to turn off. In other embodiments, the enable level of the second switching unit 20 is low, and the disable level is high. When the energy storage device is connected to a charger, the charger detection terminal BS can be low to control the second switching unit 20 to turn on; when the energy storage device is not connected to a charger, the charger detection terminal BS can be high to control the second switching unit 20 to turn off.

[0043] For example, when the energy storage device is connected to the charger, the second switching unit 20 is turned on, and the potential level of the over-discharge voltage terminal DO is approximately the same as that of the first fixed voltage terminal VG1. At this time, the potential level of the first node N1 is only related to the potential level of the overcharge voltage terminal CO, that is, the potential level of the first node N1 is only related to whether the battery pack is overcharged.

[0044] Optionally, the overcharge voltage terminal CO is configured such that when the battery pack is overcharged, the potential of the overcharge voltage terminal CO is at the disabled level of the third switching unit 30, and when the battery pack is not overcharged, the potential of the overcharge voltage terminal CO is at the enabled level of the third switching unit 30; the overdischarge voltage terminal DO is configured such that when the battery pack is overdischarged, the potential of the overdischarge voltage terminal DO is at the disabled level of the third switching unit 30, and when the battery pack is not overdischarged, the potential of the overdischarge voltage terminal DO is at the enabled level of the third switching unit 30.

[0045] For example, taking the enable level of the third switch unit 30 as high and the disable level as low, when the battery pack is overcharged, the overcharge voltage terminal CO is low and the over-discharge voltage terminal DO is high; when the battery pack is over-discharged, the overcharge voltage terminal CO is high and the over-discharge voltage terminal DO is low.

[0046] When the battery pack is overcharged, if the energy storage device is not connected to a charger, the conduction state of the third switching unit 30 is only related to the over-discharge voltage terminal DO. When the battery pack is over-discharged, the over-discharge voltage terminal DO is at a low level, the third switching unit 30 is turned off, the sampling terminal TV has no sampling signal, and the battery pack does not discharge. When the battery pack is not over-discharged, the over-discharge voltage terminal DO is at a high level, the third switching unit 30 is turned on, the sampling terminal TV has a sampling signal, and the battery pack can discharge. When the battery pack is overcharged, if the energy storage device is connected to a charger, the potential level of the over-discharge voltage terminal DO is approximately the same as that of the first fixed voltage terminal VG1. The over-discharge voltage terminal DO is at a low level, which can control the third switching unit 30 to turn off, the sampling terminal TV has no sampling signal, and the battery pack does not charge.

[0047] When the battery pack is not overcharged, if the energy storage device is not connected to a charger, the conduction states of the second switch unit 20 and the third switch unit 30 are both related to the over-discharge voltage terminal DO. When the battery pack is over-discharged, the over-discharge voltage terminal DO is at a low level, the third switch unit 30 is off, the sampling terminal TV has no sampling signal, and the battery pack does not discharge. When the battery pack is not over-discharged, the over-discharge voltage terminal DO is at a high level, the third switch unit 30 is on, the sampling terminal TV has a sampling signal, and the battery pack can discharge. When the battery pack is not overcharged, if the energy storage device is connected to a charger, the potential level of the over-discharge voltage terminal DO is approximately the same as that of the first fixed voltage terminal VG1, and the over-discharge voltage terminal DO remains at a low level. The conduction state of the third switch unit 30 is related to the over-charge voltage terminal CO. When the battery pack is overcharged, the over-charge voltage terminal CO is at a low level, the third switch unit 30 is off, the sampling terminal TV has no sampling signal, and the battery pack does not charge. When the battery pack is not overcharged, the over-charge voltage terminal CO is at a high level, the third switch unit 30 is on, the sampling terminal TV has a sampling signal, and the battery pack can charge.

[0048] Optionally, the potential of the first fixed voltage terminal VG1 is the enable level of the first switching unit 10 and the disable level of the third switching unit 30.

[0049] In some embodiments, the enable level of the first switching unit 10 is low, the enable level of the third switching unit 30 is high, and the potential of the first fixed voltage terminal VG1 can be low; in other embodiments, the enable level of the first switching unit 10 is high, the enable level of the third switching unit 30 is low, and the potential of the first fixed voltage terminal VG1 can be high.

[0050] For example, taking the enable level of the first switching unit 10 as low, the enable level of the third switching unit 30 as high, and the potential of the first fixed voltage terminal VG1 as low, when the energy storage device is connected to the charger, the second switching unit 20 is turned on, and the potential level of the over-discharge voltage terminal DO is approximately the same as that of the first fixed voltage terminal VG1, both being low. At this time, the potential of the first fixed voltage terminal VG1 can control the first switching unit 10 to turn on, but it will not control the third switching unit 30 to turn on. The conduction state of the third switching unit 30 is only related to the over-charge voltage terminal CO, that is, only related to whether the battery pack is over-discharged.

[0051] Based on the above embodiments, the first switching unit 10 includes a first transistor Q2, and the third switching unit 50 includes a third transistor Q3; the first terminal of the first transistor Q2 is electrically connected to the overcharge voltage terminal CO, the second terminal of the first transistor Q2 is electrically connected to the gate of the third transistor Q3, and the gate of the first transistor Q2 is electrically connected to the first fixed voltage terminal VG1 through the second switching unit 20; the first terminal of the third transistor Q3 is electrically connected to the sampling terminal TV, and the second terminal of the third transistor Q3 is electrically connected to the second fixed voltage terminal CG2; wherein, the first fixed voltage terminal VG1 is the ground terminal GND, the first transistor Q2 is a P-type transistor, and the third transistor Q3 is an N-type transistor.

[0052] When the first transistor Q2 is a P-type transistor, the first electrode of the first transistor Q2 is the source and the second electrode of the first transistor Q2 is the drain; when the third transistor Q3 is an N-type transistor, the first electrode of the third transistor Q3 is the drain and the second electrode of the third transistor Q3 is the source.

[0053] For example, taking the enable potential of the second switching unit 20 as high level and the disable potential as low level, the second switching unit 20 includes a second transistor Q7. The second transistor Q7 can be an N-type transistor. When the second transistor Q7 is an N-type transistor, the first terminal of the second transistor Q7 is the drain, and the first terminal of the second transistor Q7 is electrically connected to the gate of the first transistor Q2. The second terminal of the second transistor Q7 is the source, and the second terminal of the second transistor Q7 is electrically connected to the first fixed voltage terminal VG1. At this time, the first fixed voltage terminal VG1 and the second fixed voltage terminal VG2 can both be ground terminals GND.

[0054] Continue to refer to Figure 1When the battery pack is overcharged, the overcharge voltage terminal CO outputs a low level, and the over-discharge voltage terminal DO outputs a high level. When the charger is connected, the charger detection terminal BS is high, the second transistor Q7 is turned on, the over-discharge voltage terminal DO is pulled low, and both the overcharge voltage terminal CO and the over-discharge voltage terminal DO are low. The third transistor Q3 cannot be turned on at this time, and the sampling terminal TV cannot be connected to the ground terminal GND. At this time, the sampling terminal TV is floating, and the charger cannot detect the sampling signal of the sampling terminal TV. At this time, the charger recognizes the signal incorrectly and closes the charging circuit. When the charger is not connected, the charger detection terminal BS is low, the second transistor Q7 is turned off, and the high level of the over-discharge voltage terminal DO can pull the gate of the third transistor Q3 high, and the third transistor Q3 is turned on. At this time, the sampling terminal TV can be connected to the ground terminal GND, and the host of the electrical load can read the sampling signal at this time and discharge can be performed.

[0055] When the battery pack is in an over-discharge state, the overcharge voltage terminal CO outputs a high level, and the over-discharge voltage terminal DO outputs a low level. When there is no charger, the charger detection terminal BS is low, the second transistor Q7 is off, and the low-level signal of the first fixed voltage terminal VG1 cannot be transmitted to the gate of the first transistor Q2. The first transistor Q2 is off, so the high level of the overcharge voltage terminal CO cannot be transmitted to the gate of the third transistor Q3. The third transistor Q3 is also off, and the sampling terminal TV cannot be connected to the ground terminal GND. At this time, the sampling terminal TV is floating, and the host of the electrical load cannot read the sampling signal and cannot discharge. When the charger is connected, the charger detection terminal BS is high, the second transistor Q7 is turned on, and the low-level signal of the first fixed voltage terminal VG1 is transmitted to the gate of the first transistor Q2. The first transistor Q2 is turned on, and the high level of the overcharge voltage terminal CO is pulled high by the first transistor Q2 to the gate of the third transistor Q3. The third transistor Q3 is turned on, and the sampling terminal TV is connected to the ground terminal GND. The charger can detect the sampling signal and open the charging circuit to charge the battery. Based on the above embodiments, the charge / discharge protection circuit further includes: a first diode D1, a second diode D2, and a third diode D3; the anode of the first diode D1 is electrically connected to the second electrode of the first transistor Q2, and the cathode of the first diode D2 is electrically connected to the gate of the third transistor Q3 at the first node; the anode of the second diode D2 is electrically connected to the over-discharge voltage terminal DO, and the cathode of the second diode D2 is electrically connected to the gate of the third transistor Q3 at the first node N1; the anode of the third diode D3 is electrically connected to the over-discharge voltage terminal DO, and the cathode of the third diode D3 is electrically connected to the ground terminal GND through the second switching unit 20.

[0056] Based on the above embodiments, the charge and discharge protection circuit further includes: a first voltage divider resistor R4 and a second voltage divider resistor R8; the first voltage divider resistor R4 is connected in series between the overcharge voltage terminal CO and the gate of the first transistor Q2; the second voltage divider resistor R8 is connected in series between the gate of the first transistor Q2 and the second switching unit 20.

[0057] For example, when the charger is connected, the charger detection terminal BS is at a high level, the second transistor Q7 is turned on, and the second voltage divider resistor R8 is connected to the ground terminal GND. At this time, the gate voltage of the first transistor Q2 is divided by the first voltage divider resistor R4 and the second voltage divider resistor R8, so that there is a voltage difference between the gate and the source of the first transistor Q2. The gate-source voltage is less than its threshold voltage, and the first transistor Q2 is turned on.

[0058] Based on the above embodiments, the charge and discharge protection circuit further includes: a third voltage divider resistor R3 and a fourth voltage divider resistor R6; the first end of the third voltage divider resistor R3 is electrically connected to the second electrode of the first transistor Q2 at the first node N1, and the second end of the third voltage divider resistor R3 is electrically connected to the gate of the third transistor Q3; the fourth voltage divider resistor R6 is connected in series between the gate of the third transistor Q3 and the second fixed voltage terminal VG2, and the second fixed voltage terminal VG2 is the ground terminal GND.

[0059] For example, when the first node N1 is high, the fourth voltage divider resistor R6 is connected to the ground terminal GND. At this time, the gate voltage of the third transistor Q3 is divided by the third voltage divider resistor R3 and the fourth voltage divider resistor R6, resulting in a voltage difference between the gate and source of the third transistor Q3. The gate-source voltage is greater than its threshold voltage, and the third transistor Q3 is turned on.

[0060] Based on the above embodiments, the charge and discharge protection circuit further includes: a first protection resistor R15, the first end of the first protection resistor R15 being electrically connected to the over-discharge voltage terminal DO, and the second end of the first protection resistor R15 being electrically connected to the anode of the third diode D3.

[0061] Based on the above embodiments, the charge and discharge protection circuit further includes: a second protection resistor R22, the first end of the second protection resistor R22 being electrically connected to the charger detection terminal BS, and the second end of the second protection resistor R22 being electrically connected to the gate of the second transistor Q7.

[0062] Based on the above embodiments, the charge and discharge protection circuit further includes: a filter resistor R25 and a filter capacitor C6, which are connected in parallel between the charger detection terminal BS and the first fixed voltage terminal VG1.

[0063] Based on the same inventive concept, embodiments of this application also provide an energy storage device, including the charge / discharge protection circuit provided in any embodiment of this application. The energy storage device provided in embodiments of this application can be connected to a charger or to an electrical device. When connected to an electrical device, it can be embedded in the electrical device to form an integrated structure, such as the battery and drill of an electric drill.

[0064] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application, the scope of which is determined by the scope of the appended claims.

Claims

1. A charge / discharge protection circuit, characterized in that, include: Overcharge voltage terminal, over-discharge voltage terminal, charger detection terminal, sampling terminal, first switching unit, second switching unit, and third switching unit; The overcharge voltage terminal is electrically connected to the control terminal of the third switch unit through the first switch unit, and the overdischarge voltage terminal is electrically connected to the control terminal of the third switch unit; Both the control terminal of the first switch unit and the control terminal of the third switch unit are connected to the first fixed voltage terminal through the second switch unit, and the control terminal of the second switch unit is electrically connected to the charger detection terminal. The sampling terminal is connected to the second fixed voltage terminal through the third switching unit; The overcharge voltage terminal and the over-discharge voltage terminal jointly control the on / off state of the third switching unit, and the charger detection terminal controls the on / off state of the second switching unit to selectively enable the overcharge voltage terminal to control the third switching unit.

2. The charge / discharge protection circuit according to claim 1, characterized in that, The charge / discharge protection circuit is applied to energy storage devices; The charger detection terminal is configured such that when the energy storage device is connected to a charger, the potential of the charger detection terminal is the enable level of the second switching unit, and when the energy storage device is not connected to a charger, the potential of the charger detection terminal is the disable level of the second switching unit.

3. The charge / discharge protection circuit according to claim 1, characterized in that, The charge / discharge protection circuit is applied to an energy storage device, which includes a battery pack. The overcharge voltage terminal is configured such that when the battery pack is overcharged, the potential of the overcharge voltage terminal is the disabled level of the third switching unit, and when the battery pack is not overcharged, the potential of the overcharge voltage terminal is the enabled level of the third switching unit. The over-discharge voltage terminal is configured such that when the battery pack is over-discharged, the potential of the over-discharge voltage terminal is the disabled level of the third switching unit, and when the battery pack is not over-discharged, the potential of the over-discharge voltage terminal is the enabled level of the third switching unit.

4. The charge / discharge protection circuit according to claim 1, characterized in that, The potential of the first fixed voltage terminal is the enable level of the first switching unit and the disable level of the third switching unit.

5. The charge / discharge protection circuit according to claim 4, characterized in that, The first switching unit includes a first transistor, and the third switching unit includes a third transistor; The first terminal of the first transistor is electrically connected to the overcharge voltage terminal, the second terminal of the first transistor is electrically connected to the gate of the third transistor, and the gate of the first transistor is electrically connected to the first fixed voltage terminal through the second switching unit; the first terminal of the third transistor is electrically connected to the sampling terminal, and the second terminal of the third transistor is electrically connected to the second fixed voltage terminal. Wherein, the first fixed voltage terminal is a ground terminal, the first transistor is a P-type transistor, and the third transistor is an N-type transistor.

6. The charge / discharge protection circuit according to claim 5, characterized in that, Also includes: First diode, second diode, and third diode; The anode of the first diode is electrically connected to the second electrode of the first transistor, and the cathode of the first diode is electrically connected to the gate of the third transistor at the first node; The anode of the second diode is electrically connected to the over-discharge voltage terminal, and the cathode of the second diode is electrically connected to the gate of the third transistor at the first node; The anode of the third diode is electrically connected to the over-discharge voltage terminal, and the cathode of the third diode is electrically connected to the ground terminal through the second switching unit.

7. The charge / discharge protection circuit according to claim 5, characterized in that, Also includes: First voltage divider resistor, second voltage divider resistor; The first voltage divider resistor is connected in series between the overcharge voltage terminal and the gate of the first transistor; The second voltage divider resistor is connected in series between the gate of the first transistor and the second switching unit.

8. The charge / discharge protection circuit according to claim 5, characterized in that, Also includes: Third voltage divider resistor, fourth voltage divider resistor; The first end of the third voltage divider resistor is electrically connected to the second terminal of the first transistor at the first node, and the second end of the third voltage divider resistor is electrically connected to the gate of the third transistor. The fourth voltage divider resistor is connected in series between the gate of the third transistor and the second fixed voltage terminal, which is a ground terminal.

9. The charge / discharge protection circuit according to claim 1, characterized in that, Also includes: Thermosensitive resistor; The second fixed voltage terminal is the ground terminal; The sampling terminal is electrically connected to the ground terminal through the temperature-sensitive resistor and the third switching unit.

10. An energy storage device, characterized in that, include: The charge / discharge protection circuit according to any one of claims 1-9.

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