Battery pack with charging and discharging protection function for flat-adjusting handheld station

Abstract

The utility model discloses a battery pack with a charging and discharging protection function for a flat-adjusting handheld station, and relates to a battery pack capable of managing charging and discharging. In order to overcome the problem that the existing nickel-metal hydride battery charger cannot timely cut off a discharge loop when the detection function and the control function of a power supply detection controller cannot work normally, the nickel-metal hydride battery charger comprises N battery cells which are connected in series, the positive electrode of the battery located at one end is electrically connected with a VDD pin of the power supply detection controller through a resistor R1 and is electrically connected with a positive contact of a charging end; the negative contact of the charging end is connected with the power ground; the cathode of the voltage-regulator tube D5 is electrically connected with the anode of the battery located at one end, and the anode of the voltage-regulator tube D5 is electrically connected between the anode of the diode D2 and the negative contact of the discharging end through a resistor R5 and a resistor R6 in sequence.

Description

Technical Field

[0001] The utility model relates to a battery pack with manageable charging and discharging. Background Art

[0002] At present, because nickel-metal hydride batteries have good low-temperature discharge performance, nickel-metal hydride battery packs are widely used in horizontal handheld stations in cold northern regions. Nickel-metal hydride batteries are composed of hydrogen ions and metal nickel. The positive electrode is nickel oxide or hydroxide, and the negative electrode is metal hydride. When the battery is charged, hydrogen ions are released from the electrolyte, and the metal compound at the negative electrode absorbs the hydrogen ions. When discharging, these released hydrogen ions will return to their original place through the reverse process.

[0003] However, once the NiMH battery pack is overcharged during charging, the positive and negative electrodes of the battery cell will easily swell, causing the active materials to fall off and the diaphragm to be damaged, the conductive network to be destroyed, and the ohmic polarization of the battery to increase. Once over-discharge occurs during discharge, the internal pressure of the battery cell will increase, and the reversibility of the positive and negative active materials will be destroyed, so that charging can only be partially restored, and the capacity of the battery pack will be significantly attenuated. When the charging current is too large, the voltage of the battery pack will rise rapidly. When the charger detects that the voltage reaches the charging cut-off voltage, it stops charging. At this time, the battery cannot be truly fully charged, that is, there is virtual electricity. When the discharge current is too large (or short-circuited), the battery temperature will rise, resulting in electrolyte loss and a reduction in the capacity of the battery pack. Excessive heat accumulation or instantaneous high temperature may even cause the battery pack shell to rupture or even explode.

[0004] However, the existing nickel-metal hydride battery charger can only protect the battery pack from overcharging and charging overcurrent based on the existing power detection controller, and the accuracy is limited. It is unable to cut off the discharge circuit in time when the detection function and control function of the power detection controller cannot work normally, causing overdischarge to the battery and affecting the battery life. Utility Model Content

[0005] The utility model aims to overcome the problem that the existing nickel-metal hydride battery charger cannot cut off the discharge circuit in time when the detection function and control function of the power detection controller cannot work normally, and provides a battery pack for a level-adjustable handheld station with a charge and discharge protection function.

[0006] The utility model discloses a battery pack for a level-adjustable handheld station with a charge and discharge protection function, comprising N batteries of the same specification, a battery control unit, a secondary discharge protection unit, a charging terminal and a discharging terminal; wherein N is an even number;

[0007] The battery control unit includes a first MOSFET, a second MOSFET, a power detection controller, resistors R1 to R3, a diode D1, a diode D2 and a capacitor C2;

[0008] N cells are connected in series; the positive electrode of the battery at one end is electrically connected to the VDD pin of the power detection controller through a resistor R1, and is electrically connected to the positive contact of the charging end; the negative contact of the charging end is connected to the power ground;

[0009] The midpoint of the N battery cells connected in series is electrically connected to the VC pin of the power detection controller through the resistor R2, and is electrically connected to the VSS pin of the power detection controller through the resistor R2 and the capacitor C2; the negative electrode of the battery cell at the other end is connected to the power ground;

[0010] The CS pin of the power detection controller is electrically connected to the negative contact of the discharge end through the resistor R3;

[0011] The OD pin of the power detection controller is electrically connected to the gate of the first MOSFET, and the OC pin is electrically connected to the gate of the second MOSFET; and the drain of the first MOSFET is electrically connected to the source of the second MOSFET;

[0012] The anode and cathode of the diode D1 are electrically connected to the source and drain of the first MOSFET respectively, and the anode of the diode D1 and the source of the first MOSFET are both connected to the power ground;

[0013] The anode and cathode of the diode D2 are electrically connected to the source and drain of the second MOSFET respectively, and the anode of the diode D2 and the source of the second MOSFET are both electrically connected to the negative contact of the discharge terminal;

[0014] The secondary discharge protection unit includes a voltage regulator tube D5, a transistor Q2, a transistor Q3 and resistors R5 to R7;

[0015] The cathode of the voltage regulator tube D5 is electrically connected to the positive electrode of the battery at one end, and the anode is electrically connected to the anode of the diode D2 and the negative contact of the discharge end through the resistor R5 and the resistor R6 in sequence;

[0016] The base of transistor Q3 is electrically connected between resistor R5 and resistor R6, the emitter is electrically connected to the negative contact of the discharge end, and the collector is electrically connected to the base of transistor Q2 through resistor R7; the emitter of transistor Q2 is electrically connected to the positive electrode of the battery at one end, and the collector is electrically connected to the positive contact of the discharge end.

[0017] Furthermore, it also includes a secondary charging protection unit;

[0018] The secondary charging protection unit includes a transistor Q1, a resistor R4, a voltage regulator D3 and a diode D4;

[0019] The cathode of the voltage regulator tube D3 is electrically connected between the positive electrode of the battery at one end and the positive contact of the charging end, the anode is electrically connected to the anode of the diode D4, and the cathode of the diode D4 is electrically connected to the anode of the diode D2;

[0020] The emitter of transistor Q1 is electrically connected between the positive electrode of the battery at one end and the positive contact of the charging end through resistor R4, the collector is electrically connected to the anode of diode D2, and the base is electrically connected between the anode of Zener tube D3 and the anode of diode D4.

[0021] Further, a thermistor is included;

[0022] The positive electrode of the battery at one end is electrically connected to one end of the resistor R1 through the thermistor.

[0023] Furthermore, the battery cell is a nickel-metal hydride battery cell.

[0024] Furthermore, the power detection controller is a HY2120 battery manager.

[0025] The beneficial effects of the utility model are: when the detection function and control function of the power detection controller cannot work normally, the discharge circuit can be cut off in time, which can effectively prevent the battery pack from being irreversibly damaged, solve the problem of short use time and frequent charging due to the reduction of battery pack capacity, and improve the operation efficiency of shunting. It can solve the waste caused by the nickel-hydrogen battery pack currently used for horizontal handheld platforms that does not have charging and discharging protection function and often needs to be replaced within the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a battery pack for a level-adjustable handheld station with a charge-discharge protection function according to the utility model;

[0027] Figure 2 The utility model is a circuit topology diagram of a battery pack for a level-adjustable handheld station with charge and discharge protection functions. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention. Specific implementation method 1

[0032] A battery pack for a level-adjustable handheld station with a charge and discharge protection function in this embodiment includes N battery cells 1 of the same specification, a battery control unit 8, a secondary discharge protection unit 6, a charging terminal 2 and a discharging terminal 3; wherein N is an even number;

[0033] The battery control unit 8 includes a first MOSFET, a second MOSFET, a power detection controller 4, resistors R1 to R3, a diode D1, a diode D2 and a capacitor C2;

[0034] N battery cells 1 are connected in series; the positive electrode of the battery cell 1 at one end is electrically connected to the VDD pin of the power detection controller 4 through the resistor R1, and is electrically connected to the positive contact of the charging terminal 2; the negative contact of the charging terminal 2 is connected to the power ground;

[0035] The midpoint of the N battery cells 1 connected in series is electrically connected to the VC pin of the power detection controller 4 through the resistor R2, and is electrically connected to the VSS pin of the power detection controller 4 through the resistor R2 and the capacitor C2; the negative electrode of the battery cell 1 at the other end is connected to the power ground;

[0036] The CS pin of the power detection controller 4 is electrically connected to the negative contact of the discharge terminal 3 through the resistor R3;

[0037] The OD pin of the power detection controller 4 is electrically connected to the gate of the first MOSFET, and the OC pin is electrically connected to the gate of the second MOSFET; and the drain of the first MOSFET is electrically connected to the source of the second MOSFET;

[0038] The anode and cathode of the diode D1 are electrically connected to the source and drain of the first MOSFET respectively, and the anode of the diode D1 and the source of the first MOSFET are both connected to the power ground;

[0039] The anode and cathode of the diode D2 are electrically connected to the source and drain of the second MOSFET respectively, and the anode of the diode D2 and the source of the second MOSFET are both electrically connected to the negative contact of the discharge terminal 3;

[0040] The secondary discharge protection unit 6 includes a voltage regulator tube D5, a transistor Q2, a transistor Q3 and resistors R5 to R7;

[0041] The cathode of the voltage regulator tube D5 is electrically connected to the positive electrode of the battery at one end, and the anode is electrically connected between the anode of the diode D2 and the negative contact of the discharge terminal 3 through the resistor R5 and the resistor R6 in sequence;

[0042] The base of transistor Q3 is electrically connected between resistor R5 and resistor R6, the emitter is electrically connected to the negative contact of discharge terminal 3, and the collector is electrically connected to the base of transistor Q2 through resistor R7; the emitter of transistor Q2 is electrically connected to the positive electrode of the battery located at one end, and the collector is electrically connected to the positive contact of discharge terminal 3.

[0043] Specifically, the battery pack with charge and discharge protection function in this embodiment is a nickel-metal hydride battery pack dedicated to the horizontal handheld station. When performing shunting operations on site, the horizontal handheld station may be exhausted in advance due to false electricity, and the shunting signal cannot be received in time, resulting in a "fault stop". The charging overcurrent detection integrated in this embodiment avoids the formation of false electricity, and solves the hidden danger of "fault stop" caused by premature exhaustion of electricity from the source.

[0044] A battery pack for a level-adjustable handheld station with charge and discharge protection function in this embodiment adopts a self-protection design concept, and can protect against overcharging, over-discharging, charging overcurrent, discharging overcurrent, short circuit, and overheating. Compared with chargers that can only protect against charging, it has more comprehensive protection functions.

[0045] like Figure 1 and Figure 2 As shown, a cell group includes N cells 1 of the same specification: it is composed of 6 cells 1, wherein the 1st to 3rd cells are connected in series to form cell group 1, the 4th to 6th cells are connected in series to form cell group 2, and cell group 1 and cell group 2 are also connected in series.

[0046] Charging terminal 2 and discharging terminal 3: external contact points for charging and discharging of the battery pack.

[0047] Battery control unit 8: responsible for overcharge detection and control, over-discharge detection and control, discharge overcurrent and short circuit detection and control, and charge overcurrent detection and control.

[0048] Secondary discharge protection unit 6: responsible for secondary discharge protection.

[0049] like Figure 2 As shown, the specific working principle is as follows:

[0050] When overcharging, overdischarging, overcurrent discharge, and short circuit are detected through the VDD, VC, and CS pins of the power detection controller 4 (U1), it controls the first MOSFET (M1) and the second MOSFET (M2) to cut off the charging and discharging circuits to protect the battery cell group. R1 is a current limiting resistor, which is used for overvoltage detection, can stabilize VDD, and strengthen electrostatic protection ESD. R2 is a current limiting resistor, which is used for overvoltage detection, can stabilize VC, and strengthen electrostatic protection ESD. R3 is a current limiting resistor, which is used for overcurrent detection. C1 is a filter capacitor, which is used to stabilize VDD. C2 is a filter capacitor, which is used to stabilize VC. The first MOSFET is an N-channel field effect transistor (N-MOSFET), which is used for discharge control and serves as a switch to cut off and connect the discharge circuit. D1 is a freewheeling diode. The second MOSFET is an N-channel field effect transistor (N-MOSFET), which is used for charging control and serves as a switch to cut off and connect the charging circuit. D2 is a freewheeling diode. C3, D5, R5, R6, Q2, R7, Q3, and C4 constitute the second-level discharge protection. When the discharge voltage is not enough to make the Zener diode D5 conduct, the discharge circuit is cut off.

[0051] 1. Normal work

[0052] When the voltages of cell group 1 and cell group 2 are both above the over-discharge detection voltage (3.0V) and below the over-charge detection voltage (4.5V), and the CS terminal voltage is above the charge over-current detection voltage (-200mV) and below the discharge over-current detection voltage (200mV), both the OC and OD terminals of the power detection controller 4 output a high level, so that the second MOSFET and the first MOSFET are turned on at the same time. This state is a normal working state, in which charging and discharging can be carried out freely.

[0053] 2. Overcharge protection

[0054] Under normal operation, during the charging process, when the voltage of the battery cell group 1 connected to the VDD and VC terminals or the voltage of the battery cell group 2 connected to the VC and VSS terminals exceeds the overcharge detection voltage (4.5V), and this state lasts longer than the overcharge protection delay time (1000ms), the power detection controller 4 controls the output level of the OC terminal to change from a high level to a low level, and the second MOSFET connected to the OC terminal becomes closed. At this time, the charging circuit is cut off to stop the charging process.

[0055] Overcharge protection is released: When the voltages of cell group 1 and cell group 2 are both reduced to below the overcharge detection voltage (4.5V), the power detection controller 4 controls the output level of the OC terminal from a low level to a high level, and the second MOSFET connected to the OC terminal becomes turned on. At this time, the overcharge protection is released and restored to normal working state.

[0056] 3. Charging overcurrent protection

[0057] Under normal operation, during the charging process, the power detection controller 4 continuously detects the charging current by detecting the CS terminal voltage. When the CS terminal voltage is lower than the charging overcurrent detection voltage (-200mV), and this state lasts longer than the charging overcurrent protection delay time (7ms), the power detection controller 4 controls the output level of the OC terminal from a high level to a low level, and the second MOSFET connected to the OC terminal becomes closed. At this time, the discharge circuit is cut off to stop the charging process.

[0058] Charging overcurrent protection is released: When the CS terminal voltage is higher than the charging overcurrent protection voltage (-200mV), the power detection controller 4 controls the output level of the OC terminal from a low level to a high level, and the second MOSFET connected to the OC terminal becomes turned on. At this time, the charging overcurrent protection is released and returns to normal working state.

[0059] 4. Over discharge protection

[0060] Under normal operation, during the discharge process, when the voltage of the battery cell group 1 connected to the VDD and VC terminals or the voltage of the battery cell group 2 connected to the VC and VSS terminals drops below the over-discharge detection voltage (3.0V), and this state lasts longer than the over-discharge protection delay time (110ms), the power supply detection controller 4 controls the output level of the OD terminal from a high level to a low level, and the first MOSFET connected to the OD terminal becomes closed. At this time, the discharge circuit is cut off to stop the discharge process.

[0061] Over-discharge protection is released: When the voltages of cell group 1 and cell group 2 are both higher than the over-discharge detection voltage (3.0V), and the CS terminal voltage is higher than the charge over-current detection voltage (-200mV), the power detection controller 4 controls the output level of the OD terminal to change from a low level to a high level, and the first MOSFET connected to the OD terminal becomes turned on. At this time, the over-charge protection is released and returns to normal working state.

[0062] 5. Discharge overcurrent protection

[0063] Under normal operation, the power detection controller 4 continuously detects the discharge current by detecting the CS terminal voltage. When the CS terminal voltage exceeds the discharge overcurrent detection voltage (200mV), and this state lasts longer than the discharge overcurrent protection delay time (10ms), the power detection controller 4 controls the output level of the OD terminal from a high level to a low level, and the first MOSFET connected to the OD terminal becomes off. At this time, the discharge circuit is cut off to stop the discharge process.

[0064] Discharge overcurrent protection is released: When the CS terminal voltage drops to the discharge overcurrent protection voltage (200mV), the power detection controller 4 controls the output level of the OD terminal from a low level to a high level, and the first MOSFET connected to the OD terminal becomes turned on. At this time, the discharge overcurrent protection is released and returns to normal working state.

[0065] 6. Load short circuit protection

[0066] Under normal working conditions, the power detection controller 4 continuously detects the discharge current by detecting the CS terminal voltage. When the CS terminal voltage exceeds the load short-circuit detection voltage (1000mV), and this state lasts longer than the load short-circuit protection delay time (250us), the power detection controller 4 controls the output level of the OD terminal to change from a high level to a low level, and the first MOSFET connected to the OD terminal becomes off. At this time, the discharge loop is cut off to stop the short-circuit process.

[0067] Load short-circuit protection is released: When the CS terminal voltage drops to the discharge overcurrent protection voltage (200mV), the power detection controller 4 controls the output level of the OD terminal from a low level to a high level, and the first MOSFET connected to the OD terminal becomes turned on. At this time, the load short-circuit protection is released and returns to normal working state.

[0068] 7. Secondary discharge protection

[0069] Under normal operation, during the discharge process, once the detection function, control function or one of the field effect tubes of the power detection controller 4 fails to work properly, the discharge circuit cannot be cut off when the discharge voltage drops to 6.0V, and the secondary discharge protection circuit is activated.

[0070] Specifically, when the voltage continues to drop to 5.6V, the voltage regulator D5 (5.6V) is cut off, causing the base of the transistor Q3 to lose the bias voltage and be cut off. At this time, Q2 loses the base current and is also cut off. The discharge circuit is cut off and the battery will not continue to discharge.

[0071] The second-level discharge protection is released: when the series voltage of battery group 1 and battery group 2 rises to above 5.6V, the voltage regulator D5 (5.6V) reversely breaks down and turns on. At this time, the base of the transistor Q3 generates a bias voltage and turns on. After Q3 turns on, the base of the transistor Q2 will have current flowing through and turn on. The second-level discharge protection is released and returns to normal working state. Specific implementation method 2

[0073] This embodiment is a further explanation of the first embodiment. In this embodiment, a secondary charging protection unit 7 is also included;

[0074] The secondary charging protection unit 7 includes a transistor Q1, a resistor R4, a voltage regulator D3 and a diode D4;

[0075] The cathode of the voltage regulator tube D3 is electrically connected between the positive electrode of the battery cell 1 at one end and the positive contact of the charging terminal 2, the anode is electrically connected to the anode of the diode D4, and the cathode of the diode D4 is electrically connected to the anode of the diode D2;

[0076] The emitter of transistor Q1 is electrically connected between the positive electrode of the battery cell 1 at one end and the positive contact of the charging terminal 2 through resistor R4, the collector is electrically connected to the anode of diode D2, and the base is electrically connected between the anode of Zener diode D3 and the anode of diode D4.

[0077] The other technical features of this embodiment are exactly the same as those of the first embodiment.

[0078] Specifically, the secondary charging protection unit 7 is responsible for the secondary charging protection. R4, Q1, D3, and D4 constitute the secondary charging protection unit 7. When the charging voltage is higher than the breakdown voltage of the voltage regulator tube D3, the charging voltage will not continue to increase.

[0079] like Figure 2 As shown, under normal operation, during the charging process, once the detection function, control function or one of the field effect transistors of the power detection controller 4 fails to work properly, the charging circuit cannot be cut off when the charging voltage rises to 9.0V, and the secondary charging protection circuit is activated.

[0080] Specifically, when the voltage continues to rise to 9.1V, the voltage regulator D3 (9.1V) reversely breaks down and turns on. At this time, the base of the transistor Q1 generates a bias voltage and turns on. The charging circuit voltage is clamped within 10V, and the battery voltage will not continue to rise.

[0081] Secondary charging protection is released: When the series voltage of battery pack 1 and battery pack 2 drops below 9.1V, the voltage regulator D3 (9.1V) is cut off. At this time, the base of transistor Q1 loses the bias voltage and is cut off. The secondary charging protection is released and returns to normal working state. Specific implementation method three

[0083] This embodiment is a further description of the first or second embodiment. In this embodiment, a thermistor 5 is further included.

[0084] The positive electrode of the battery cell 1 at one end is electrically connected to one end of the resistor R1 through the thermistor 5 .

[0085] The other technical features of this embodiment are exactly the same as those of embodiment one or two.

[0086] Specifically, thermistor 5 (PTC): used for temperature protection, the resistor uses a positive temperature coefficient PTC thermistor, which can cut off the current when the battery pack exceeds a certain temperature, playing the role of overheating protection. It can avoid the explosion risk caused by excessive instantaneous current and high temperature.

[0087] When the battery pack heats up to a certain temperature due to high current charging and discharging or short circuit, the thermistor changes from a conductive state to an insulating state to cut off the circuit and protect the battery pack.

[0088] like Figure 2 As shown, under normal operation, once the current inside the battery cell is too large or an external short circuit occurs, the temperature of the battery cell group will rise. When the temperature exceeds the Curie temperature (120°C) of the positive temperature coefficient thermistor F1, the resistance of the thermistor F1 increases in a step-like manner, and it changes from a good conductive state to an insulating state, thereby cutting off the charge and discharge circuit.

[0089] Overheat protection is released: When the temperature of the battery pack drops below the Curie temperature (120℃) of the thermistor F1, the resistance of the thermistor F1 is restored, and it changes from an insulating state to a good conductive state to connect the circuit. At this time, the overheat protection is released and returns to normal working state. Specific implementation method four

[0091] This embodiment is a further description of the third embodiment. In this embodiment, the battery cell 1 is a nickel-metal hydride battery cell.

[0092] The other technical features of this embodiment are exactly the same as those of the third embodiment. Specific implementation method five

[0094] This embodiment is a further description of the first, second or fourth embodiment. In this embodiment, the power detection controller 4 is a HY2120 battery manager.

[0095] The other technical features of this embodiment are exactly the same as those of embodiments one, two or four.

[0096] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A battery pack for a level-adjustable handheld station with charge and discharge protection function, characterized in that: It comprises N battery cells (1) of the same specification, a battery control unit (8), a secondary discharge protection unit (6), a charging end (2) and a discharging end (3); wherein N is an even number; The battery control unit (8) comprises a first MOSFET, a second MOSFET, a power detection controller (4), resistors R1 to R3, a diode D1, a diode D2 and a capacitor C2; N battery cells (1) are connected in series; the positive electrode of the battery cell (1) at one end is electrically connected to the VDD pin of the power detection controller (4) through a resistor R1, and is electrically connected to the positive contact of the charging end (2); the negative contact of the charging end (2) is connected to the power ground; The midpoint of the N battery cells (1) connected in series is electrically connected to the VC pin of the power detection controller (4) through a resistor R2, and is electrically connected to the VSS pin of the power detection controller (4) through a resistor R2 and a capacitor C2; the negative electrode of the battery cell (1) at the other end is connected to the power ground; The CS pin of the power detection controller (4) is electrically connected to the negative contact of the discharge terminal (3) through the resistor R3; The OD pin of the power detection controller (4) is electrically connected to the gate of the first MOSFET, and the OC pin is electrically connected to the gate of the second MOSFET; and the drain of the first MOSFET is electrically connected to the source of the second MOSFET; The anode and cathode of the diode D1 are electrically connected to the source and drain of the first MOSFET respectively, and the anode of the diode D1 and the source of the first MOSFET are both connected to the power ground; The anode and cathode of the diode D2 are electrically connected to the source and drain of the second MOSFET respectively, and the anode of the diode D2 and the source of the second MOSFET are both electrically connected to the negative contact of the discharge terminal (3); The secondary discharge protection unit (6) comprises a voltage regulator tube D5, a transistor Q2, a transistor Q3 and resistors R5-R7; The cathode of the voltage regulator tube D5 is electrically connected to the positive electrode of the battery at one end, and the anode is electrically connected to the anode of the diode D2 and the negative contact of the discharge end (3) through the resistor R5 and the resistor R6 in sequence; The base of the transistor Q3 is electrically connected between the resistor R5 and the resistor R6, the emitter is electrically connected to the negative contact of the discharge terminal (3), and the collector is electrically connected to the base of the transistor Q2 through the resistor R7; the emitter of the transistor Q2 is electrically connected to the positive electrode of the battery located at one end, and the collector is electrically connected to the positive contact of the discharge terminal (3).

2. A battery pack for a level-adjustable handheld station with charge and discharge protection function according to claim 1, characterized in that: It also includes a secondary charging protection unit (7); The secondary charging protection unit (7) comprises a transistor Q1, a resistor R4, a voltage regulator tube D3 and a diode D4; The cathode of the voltage regulator tube D3 is electrically connected between the positive electrode of the battery cell (1) at one end and the positive contact of the charging end (2), the anode is electrically connected to the anode of the diode D4, and the cathode of the diode D4 is electrically connected to the anode of the diode D2; The emitter of the transistor Q1 is electrically connected between the positive electrode of the battery cell (1) at one end and the positive contact of the charging end (2) through a resistor R4, the collector is electrically connected to the anode of the diode D2, and the base is electrically connected between the anode of the voltage regulator tube D3 and the anode of the diode D4.

3. A battery pack for a level-adjustable handheld station with charge and discharge protection function according to claim 1 or 2, characterized in that: Also includes a thermistor (5); The positive electrode of the battery cell (1) at one end is electrically connected to one end of the resistor R1 via the thermistor (5).

4. A battery pack for a level-adjustable handheld station with charge and discharge protection function according to claim 3, characterized in that: The battery cell (1) is a nickel-hydrogen battery cell.

5. A battery pack for a level-adjustable handheld station with charge and discharge protection function according to claim 1, 2 or 4, characterized in that: The power detection controller (4) is a HY2120 battery manager.

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