Lithium battery pack charging protection circuit and protection board thereof

Abstract

The present application relates to the technical field of battery charging protection, and more particularly to a lithium battery pack charging protection circuit and a protection board thereof. The lithium battery pack charging protection circuit comprises an MCU chip, a switching module, a charging detection module and a charging activation module. The switching module is connected between the positive electrode of the battery pack and the positive electrode port of the charging end. The charging activation module comprises a first optocoupler chip. The LED lamp of the first optocoupler chip is connected in series between the positive electrode port and the negative electrode port of the charging end. The driving member is connected in series between the positive electrode of the battery pack and the voltage terminal of the MCU chip. The charging detection module is connected between the positive electrode port of the charging end and the signal input terminal of the MCU chip. The first signal output terminal of the MCU chip is connected with the control terminal of the switching module. The present application uses the charging activation module to isolate the voltage terminal of the battery pack from the charging end, so as to realize the automatic shutdown effect of the charging activation module under the condition that the lithium battery pack is not in the same ground. The charging detection module is used to realize the accurate identification and detection of the charging voltage.

Description

Technical Field

[0001] This invention relates to the technical field of battery charging protection, and more specifically, to a lithium battery pack charging protection circuit and its protection board. Background Technology

[0002] The negative ground of the lithium battery pack cells and the charging system are not shared; that is, the negative ground of the battery cells and the negative ground of the charging system do not share the same ground. When the negative ground of the lithium battery pack cells and the negative ground of the charging system share the same ground, and the load on the discharge end of the lithium battery pack is not removed, if a high-voltage abnormal charger is plugged into the charging end of the lithium battery, the protection circuit of the lithium battery pack may fail to shut off after charging activation and may fail to correctly detect whether the voltage of the plugged-in charger is within the normal range. This could lead to the lithium battery pack system failing to shut off properly or damaging the lithium battery pack. Summary of the Invention

[0003] To overcome the problem described in the background art that the non-grounded lithium battery pack protection circuit cannot properly shut down and detect the charging voltage after being activated by a high-voltage abnormal charger, the present invention provides a lithium battery pack charging protection circuit and its protection board.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] In a first aspect, the present invention provides a lithium battery pack charging protection circuit, including an MCU chip, a switching module, a charging detection module, and a charging activation module;

[0006] The switch module is connected between the positive terminal of the battery pack and the positive terminal of the charging terminal, and is used to connect the positive terminal of the battery pack to the positive terminal of the charging terminal.

[0007] The charging activation module includes a first optocoupler chip. The two ends of the LED of the first optocoupler chip are connected in series between the positive and negative terminals of the charging terminal. The two ends of the driving component are connected in series between the positive terminal of the battery pack and the voltage terminal of the MCU chip, which is used to activate the MCU chip and isolate the voltage terminal of the battery pack from the charging terminal.

[0008] The charging detection module includes a dual-channel comparator chip, a second optocoupler chip, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. One end of the second resistor is connected to the positive port of the charging terminal, and the other end is connected to the negative port of the charging terminal through the third resistor. One end of the fourth resistor is connected to the positive port of the charging terminal, and the other end is connected to the negative port of the charging terminal through the fifth resistor. The two ends of the LED of the second optocoupler chip are connected in series between the positive and negative ports of the charging terminal. The input terminal of the driver is connected between the rated voltage source and the second signal input terminal of the MCU chip, and the output terminal of the driver is grounded. The sixth resistor is connected in series with the second optocoupler chip. The positive terminal of the LED of the optocoupler chip is connected to the positive terminal of the charging terminal; the dual-channel comparator chip is provided with a first comparator channel and a second comparator channel, the positive terminal of the first comparator channel and the negative terminal of the second comparator channel are both connected between the second resistor and the third resistor, the negative terminal of the first comparator channel is connected between the fifth resistor and the fourth resistor, and the positive terminal of the second comparator channel is connected between the fourth resistor and the positive terminal of the charging terminal; the output terminals of the first comparator channel and the second comparator channel are both connected between the positive terminal of the LED of the second optocoupler chip and the sixth resistor, for controlling the MCU chip to conduct the switching module;

[0009] The first signal output terminal of the MCU chip is connected to the control terminal of the switch module, and is used to control the switch module to be turned on.

[0010] Preferably, the circuit further includes a power supply module, the input terminal of which is connected to the positive terminal of the battery pack, and the output terminal of which is connected to the voltage terminal of the MCU chip;

[0011] The charging activation module further includes a first transistor, a second transistor, a first capacitor, and a first resistor. The first capacitor is connected in series between the driver output terminal of the first optocoupler chip and the base of the first transistor. The first resistor is connected in parallel with the first capacitor. The collector of the first transistor is connected to the control terminal of the power supply module, and the emitter is grounded. The collector of the second transistor is connected to the control terminal of the power supply module, the base is connected to the signal control terminal of the MCU chip, and the emitter is grounded.

[0012] Preferably, both the first transistor and the second transistor are NPN transistors.

[0013] Preferably, the charging detection module is further provided with a voltage regulator module, one end of which is connected between the fourth resistor and the sixth resistor, and the other end is connected to the negative terminal of the charging terminal.

[0014] Preferably, the voltage regulator module includes a three-terminal voltage regulator, a seventh resistor, and an eighth resistor. The input terminal of the three-terminal voltage regulator is connected between the fourth resistor and the sixth resistor, and the output terminal is connected to the negative terminal of the charging terminal. One end of the seventh resistor is connected to the input terminal of the three-terminal voltage regulator, and the other end is connected to the output terminal of the three-terminal voltage regulator through the eighth resistor. The control terminal of the three-terminal voltage regulator is connected between the seventh resistor and the eighth resistor.

[0015] Preferably, the switching module is provided with a first MOSFET and a third transistor. The drain of the first MOSFET is connected to the positive terminal of the battery pack, the source is connected to the positive terminal of the charging terminal, and the gate is connected to the collector of the third transistor. The base of the third transistor is connected to the first signal output terminal of the MCU chip, and the transmitter is grounded.

[0016] Preferably, the switching module further includes a second MOSFET, the source of which is connected to the negative terminal of the battery pack, the drain of which is connected to the negative terminal of the charging terminal, and the gate of which is connected to the second signal output terminal of the MCU chip.

[0017] Preferably, the first MOSFET is a P-channel MOSFET; the second MOSFET is an N-channel MOSFET; and the third transistor is an NPN transistor.

[0018] Preferably, the circuit further includes a fuse and a first diode, the positive terminal of the first diode being connected to the source of the first MOSFET, and the negative terminal being connected to the positive terminal of the battery pack through the fuse.

[0019] In a second aspect, the present invention provides a lithium battery pack charging protection board, wherein the protection board is provided with the lithium battery pack charging protection circuit as described in the first aspect.

[0020] Its beneficial effects are as follows:

[0021] 1. This invention employs a first optocoupler chip on the charging activation module to isolate the voltage terminal of the battery pack from the charging terminal, achieving the effect of automatic shutdown of the charging activation module when the lithium battery pack is not grounded. Since the first optocoupler chip isolates the voltage terminal of the battery pack from the charging terminal, and the activation voltage of the MCU chip is provided by the lithium battery, the charging activation module is unaffected by the voltage level at the charging terminal or whether the load at the discharging terminal has been removed. Even when a charger with abnormally high voltage is continuously plugged into the charging terminal to activate the lithium battery pack, the charging activation module can automatically shut down, preventing the first transistor of the charging activation module from continuously conducting and activating the MCU chip, thus consuming power.

[0022] 2. This invention employs a charging detection module to accurately identify and detect the charging voltage. A dual-channel comparison chip compares the charging voltage with a preset normal voltage to determine if the charging voltage is abnormal. When the charging voltage is abnormal, the charging detection module controls the MCU chip to shut down the switching module, thus enabling accurate identification and detection of charging voltage abnormalities even when the lithium battery pack is not grounded. Attached Figure Description

[0023] Figure 1 This is a structural block diagram of the lithium battery pack charging protection circuit provided by the present invention.

[0024] Figure 2 This is a circuit diagram of the lithium battery pack charging protection circuit provided by the present invention.

[0025] Figure 3 This is a structural block diagram of the lithium battery pack charging protection board provided by the present invention.

[0026] The components include: lithium battery pack 10, switch module 20, charging terminal 30, charging detection module 40, MCU chip 50, charging activation module 60, and power supply module 70. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of the present invention.

[0028] Therefore, the following detailed description of the embodiments of the 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 invention without inventive effort are within the scope of protection of the invention.

[0029] Example 1:

[0030] like Figure 1 As shown, this embodiment provides a lithium battery pack charging protection circuit, including a switch module 20, a charging detection module 40, an MCU chip 50, and a charging activation module 60.

[0031] For details, please refer to Figure 2 The switch module 20 is connected between the positive terminal B+ of the battery pack 10 and the positive terminal C+ of the charging terminal 30. The switch module 20 is mainly used to connect the positive terminal C+ of the charging terminal 30 to the positive terminal B+ of the battery pack 10.

[0032] The charging activation module 60 includes a first optocoupler chip U1. The input terminal of the LED of the first optocoupler chip U1 is connected to the positive port C+ of the charging terminal 30, and the output terminal is connected to the negative port C- of the charging terminal 30. The two ends of the driver of the first optocoupler chip U1 are connected in series between the positive terminal of the battery pack 10 and the voltage terminal 50_9 of the MCU chip 50. The charging activation module 60 is mainly used to activate the MCU chip 50, and the first optocoupler chip U1 is used to isolate the voltage terminal of the battery pack 10 from the charging terminal 30.

[0033] In this embodiment, the driving device is an optical drive transistor, whose base is controlled by an LED, its collector is the input terminal, and its emitter is the output terminal, and so on.

[0034] In some preferred embodiments, the circuit further includes a power supply module 70, the input terminal of which is connected to the positive terminal P+ of the battery pack 10, and the output terminal is connected to the voltage terminal 50_9 of the MCU chip 50.

[0035] The charging activation module 60 also includes a first transistor Q1, a second transistor Q2, a first capacitor C1, a first resistor R1, and various voltage dividers. The first capacitor C1 is connected in series between the driver output terminal of the first optocoupler chip U1 and the base of the first transistor Q1. The first resistor R1 is connected in parallel with the first capacitor C1. The collector of the first transistor Q1 is connected to the control terminal of the power supply module 70, and its emitter is grounded. The collector of the second transistor Q2 is connected to the control terminal of the power supply module 70, its base is connected to the signal control terminal 50_3 of the MCU chip 50, and its emitter is grounded. Through the charging and discharging structure of the first capacitor C1 and the first resistor R1, the charging activation module 60 can automatically turn off after the charger is inserted and the charging process of the first capacitor C1 is completed.

[0036] In this embodiment, when designing the parameters of the charging activation module 60 components, it is necessary to ensure that within the normal output voltage range of the battery pack 10, after the charger is inserted and the charging process of the first capacitor C1 is completed, the first transistor Q1 is in the cut-off state.

[0037] The power supply module 70 is mainly used to receive the signal from the first transistor Q1, thereby pulling down the POWER signal and thus providing a +5V voltage signal to the voltage terminal of the MCU chip 50, activating the MCU chip 50. The function of the second transistor Q2 is that, after the MCU is activated, the signal control terminal 50_3 of the MCU chip 50 continuously keeps the second transistor Q2 conducting and grounded, thereby controlling the power supply module 70 to continuously pull down the POWER signal, thus continuously providing a +5V voltage signal to the voltage terminal 50_9 of the MCU chip 50, enabling the MCU chip 50 to continue operating.

[0038] In this embodiment, both the first transistor Q1 and the second transistor Q2 are NPN transistors.

[0039] The charging detection module 40 includes a dual-channel comparator chip U2, a second optocoupler chip U3, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. One end of the second resistor R2 is connected to the positive terminal C+ of the charging terminal 30, and the other end is connected to the negative terminal C- of the charging terminal 30 through the third resistor R3. One end of the fourth resistor R4 is connected to the positive terminal C+ of the charging terminal 30, and the other end is connected to the negative terminal C- of the charging terminal 30 through the fifth resistor R5. The two ends of the LED of the second optocoupler chip U3 are connected in series between the positive terminal C+ and the negative terminal of the charging terminal 30. The input terminal of the driver is connected between the rated voltage source and the second signal input terminal 50_5 of the MCU chip 50, and the output terminal of the driver is grounded. The sixth resistor R6 is connected in series between the positive terminal of the LED of the second optocoupler chip U3 and the positive terminal C+ of the charging terminal 30. The dual-channel comparator chip U2 has a first comparator channel and a second comparator channel. The positive port U2_3 of the first comparator channel and the negative port U2_6 of the second comparator channel are both connected between the second resistor R2 and the third resistor R3. The negative port U2_2 of the first comparator channel is connected between the fifth resistor R5 and the fourth resistor R4. The positive port U2_5 of the second comparator channel is connected between the fourth resistor R4 and the positive port C+ of the charging terminal 30. The output terminals U2_1 and U2_7 of the first comparator channel are both connected between the positive port of the LED of the second optocoupler chip U3 and the sixth resistor R6. This mainly activates the second optocoupler chip U3 to output a signal to the MCU chip 50, thereby enabling the MCU chip 50 to control the conduction of the switch module 20.

[0040] In this embodiment, the charging detection module 40 is further provided with a voltage regulator module, which includes a three-terminal voltage regulator Z1, a seventh resistor R7, and an eighth resistor R8. The input terminal of the three-terminal voltage regulator Z1 is connected between the fourth resistor R4 and the sixth resistor R6, and its output terminal is connected to the negative terminal C- of the charging terminal 30. One end of the seventh resistor R7 is connected to the input terminal of the three-terminal voltage regulator Z1, and the other end is connected to the output terminal of the three-terminal voltage regulator Z1 through the eighth resistor R8. The control terminal of the three-terminal voltage regulator Z1 is connected between the seventh resistor R7 and the eighth resistor R8. The voltage regulator module is mainly used to stabilize the voltage across the fourth resistor R4 and the fifth resistor R5 so that the dual-channel comparator chip U2 can compare the voltage magnitudes.

[0041] In this dual-channel comparator chip U2, the voltage signals acquired from the negative port U2_2 of the first comparator channel and the positive port U2_5 of the second comparator channel are stabilized and remain constant by the voltage regulator module. The voltage signals acquired from the positive port U2_3 of the first comparator channel and the negative port U2_6 of the second comparator channel mainly reflect the voltage magnitude of the charging terminal 30. By comparing the voltage signals acquired from the first and second comparator channels, the dual-channel comparator chip U2 can determine whether the voltage of the charging terminal 30 is normal. If the voltage of the charging terminal 30 is normal, the dual-channel comparator chip U2 activates the second optocoupler chip U3 through the output terminals U2_1 and U2_7 of the first and second comparator channels. The level signal of the second signal input terminal 50_5 of the MCU chip 50 is pulled low, thereby enabling the MCU chip 50 to operate and turn on the switching module 20 for charging.

[0042] The first signal output terminal 50_1 of the MCU chip 50 is connected to the control terminal of the switch module 20. The MCU chip 50 is mainly used to control the switch module 20 to turn on.

[0043] In this embodiment, the switching module 20 includes a first MOSFET T1, a second MOSFET T2, and a third transistor Q3. The drain of the first MOSFET T1 is connected to the positive terminal B+ of the battery pack 10, the source is connected to the positive terminal C+ of the charging terminal 30, and the gate is connected to the collector of the third transistor Q3. The base of the third transistor Q3 is connected to the first signal output terminal 50_1 of the MCU chip 50, and the transmitter is grounded. The source of the second MOSFET T2 is connected to the negative terminal B- of the battery pack 10, the drain is connected to the negative terminal C- of the charging terminal 30, and the gate is connected to the second signal output terminal 50_2 of the MCU chip 50. The first MOSFET T1 is mainly used to connect the positive terminal B+ of the battery pack 10 to the positive terminal C+ of the charging terminal 30. The third transistor Q3 is mainly used to keep the first MOSFET T1 continuously conducting. The first MOSFET T1 is mainly used to connect the negative terminal B- of the battery pack 10 to the negative terminal C- of the charging terminal 30.

[0044] In this embodiment, the first MOSFET T1 is a P-channel MOSFET. The second MOSFET T2 is an N-channel MOSFET. The third transistor Q3 is an NPN transistor.

[0045] In this embodiment, the MCU chip 50 is model CS32L010F8U6. The dual-channel comparator chip U2 is model SGM8770. The first optocoupler chip and the second optocoupler chip are both model EL357.

[0046] Through the aforementioned component connections, the working principle of this embodiment is as follows: First, the input voltage at both poles of the charging terminal 30 is activated by the charging activation module 60 to activate the power supply module 70, thereby continuously keeping the MCU chip 50 in working state. The charging activation module 60 then automatically cuts off power. Subsequently, the dual-channel comparator chip U2 in the charging detection module 40 determines whether the voltage of the charging terminal 30 is within the normal range. If the voltage of the charging terminal 30 is normal, the dual-channel comparator chip U2 activates the second optocoupler chip U3 through the output terminals U2_1 and U2_7 of the first and second comparator channels. The level signal of the second signal input terminal 50_5 of the MCU chip 50 is pulled low, thereby enabling the MCU chip 50 to operate and turn on the switch module 20 to enter the charging state. When the voltage of the charging terminal 30 is abnormal, i.e., the voltage of the charging terminal 30 is greater than or less than the normal value range, the output terminals of the first and second comparator channels of the dual-channel comparator chip U2 output a low voltage, causing the second optocoupler chip U3 to stop working. As a result, the MCU chip 50 prevents the switch module 20 from conducting and thus does not charge, thereby protecting the lithium battery.

[0047] Example 2:

[0048] The difference between this embodiment and the first embodiment is that:

[0049] This embodiment also includes a fuse F1 and a first diode D1. The anode of the first diode D1 is connected to the source of the first MOSFET T1, and the cathode is connected to the positive terminal B+ of the battery pack 10 through the fuse F1. The fuse F1 is mainly used to promptly melt and disconnect the lithium battery pack 10 when an external short circuit or a large current occurs, ensuring the operational safety of the lithium battery pack 10. The first diode D1 is mainly used to prevent reverse charging of the lithium battery pack 10 to the charger when a low-voltage charger is inserted, and to prevent interference of the lithium battery voltage on the charging voltage identification.

[0050] In this embodiment, the circuit also includes other voltage divider resistors, anti-reverse current diodes, and filter capacitors.

[0051] Example 3:

[0052] like Figure 3 As shown, this embodiment provides a lithium battery pack charging protection board, which is provided with a lithium battery pack charging protection circuit as in Embodiment 1 or Embodiment 2.

[0053] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] Although the description of the invention has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A lithium battery pack charging protection circuit, characterized in that, It includes a switch module, an MCU chip, a charging detection module, a power supply module, and a charging activation module; The switch module is connected between the positive terminal of the battery pack and the positive terminal of the charging terminal, and is used to connect the positive terminal of the battery pack to the positive terminal of the charging terminal. The charging activation module includes a first optocoupler chip. The two ends of the LED of the first optocoupler chip are connected in series between the positive and negative terminals of the charging terminal. The two ends of the driving component are connected in series between the positive terminal of the battery pack and the voltage terminal of the MCU chip, which is used to activate the MCU chip and isolate the voltage terminal of the battery pack from the charging terminal. The charging detection module includes a dual-channel comparator chip, a second optocoupler chip, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. One end of the second resistor is connected to the positive port of the charging terminal, and the other end is connected to the negative port of the charging terminal through the third resistor. One end of the fourth resistor is connected to the positive port of the charging terminal, and the other end is connected to the negative port of the charging terminal through the fifth resistor. The two ends of the LED of the second optocoupler chip are connected in series between the positive and negative ports of the charging terminal. The input terminal of the driver is connected between the rated voltage source and the second signal input terminal of the MCU chip, and the output terminal of the driver is grounded. The sixth resistor is connected in series with the second optocoupler chip. The positive terminal of the LED of the optocoupler chip is connected to the positive terminal of the charging terminal; the dual-channel comparator chip is provided with a first comparator channel and a second comparator channel, the positive terminal of the first comparator channel and the negative terminal of the second comparator channel are both connected between the second resistor and the third resistor, the negative terminal of the first comparator channel is connected between the fifth resistor and the fourth resistor, and the positive terminal of the second comparator channel is connected between the fourth resistor and the positive terminal of the charging terminal; the output terminals of the first comparator channel and the second comparator channel are both connected between the positive terminal of the LED of the second optocoupler chip and the sixth resistor, for controlling the MCU chip to conduct the switching module; The first signal output terminal of the MCU chip is connected to the control terminal of the switch module, and is used to control the switch module to be turned on.

2. The lithium battery pack charging protection circuit according to claim 1, characterized in that, The circuit also includes a power supply module, the input terminal of which is connected to the positive terminal of the battery pack, and the output terminal of which is connected to the voltage terminal of the MCU chip. The charging activation module further includes a first transistor, a second transistor, a first capacitor, and a first resistor. The first capacitor is connected in series between the driver output terminal of the first optocoupler chip and the base of the first transistor. The first resistor is connected in parallel with the first capacitor. The collector of the first transistor is connected to the control terminal of the power supply module, and the emitter is grounded. The collector of the second transistor is connected to the control terminal of the power supply module, the base is connected to the signal control terminal of the MCU chip, and the emitter is grounded.

3. The lithium battery pack charging protection circuit according to claim 2, characterized in that, Both the first transistor and the second transistor are NPN transistors.

4. The lithium battery pack charging protection circuit according to claim 1, characterized in that, The charging detection module is also equipped with a voltage regulator module. One end of the voltage regulator module is connected between the fourth resistor and the sixth resistor, and the other end is connected to the negative terminal of the charging terminal.

5. The lithium battery pack charging protection circuit according to claim 4, characterized in that, The voltage regulator module includes a three-terminal voltage regulator, a seventh resistor, and an eighth resistor. The input terminal of the three-terminal voltage regulator is connected between the fourth resistor and the sixth resistor, and the output terminal is connected to the negative terminal of the charging terminal. One end of the seventh resistor is connected to the input terminal of the three-terminal voltage regulator, and the other end is connected to the output terminal of the three-terminal voltage regulator through the eighth resistor. The control terminal of the three-terminal voltage regulator is connected between the seventh resistor and the eighth resistor.

6. The lithium battery pack charging protection circuit according to claim 1, characterized in that, The switching module is equipped with a first MOSFET and a third transistor. The drain of the first MOSFET is connected to the positive terminal of the battery pack, the source is connected to the positive terminal of the charging terminal, and the gate is connected to the collector of the third transistor. The base of the third transistor is connected to the first signal output terminal of the MCU chip, and the transmitter is grounded.

7. The lithium battery pack charging protection circuit according to claim 6, characterized in that, The switching module further includes a second MOSFET, the source of which is connected to the negative terminal of the battery pack, the drain of which is connected to the negative terminal of the charging terminal, and the gate of which is connected to the second signal output terminal of the MCU chip.

8. The lithium battery pack charging protection circuit according to claim 7, characterized in that, The first MOSFET is a P-channel MOSFET; the second MOSFET is an N-channel MOSFET; and the third transistor is an NPN transistor.

9. The lithium battery pack charging protection circuit according to claim 6, characterized in that, The circuit also includes a fuse and a first diode, the positive terminal of which is connected to the source of the first MOSFET, and the negative terminal is connected to the positive terminal of the battery pack through the fuse.

10. A lithium battery pack charging protection board, characterized in that, The protection board is provided with a lithium battery pack charging protection circuit as described in any one of claims 1 to 9.

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