Charging management system after over-discharge of lithium battery

Abstract

The invention discloses a charging management system after over-discharge of a lithium battery, which comprises a charging integrated circuit and a voltameter electrically connected with the lithium battery, the output end of the charging integrated circuit is electrically connected with the lithium battery and a system mainboard, the charging management system also comprises an auxiliary MCU (Microprogrammed Control Unit), the auxiliary MCU is electrically connected with an adapter through a voltage stabilizer, the system mainboard comprises a main control chip, and the main control chip is electrically connected with the lithium battery. A GPIO port of the auxiliary MCU is connected with a high-level starting pin of the main control chip, an I2C bus of the auxiliary MCU is connected with the voltameter after passing through a normally-open end of the double-channel analog switch, the auxiliary MCU is connected with a control end of the double-channel analog switch, an I2C bus of the main control chip is connected with the voltameter after passing through a normally-closed end of the double-channel analog switch, and an I2C bus of the main control chip is connected with the voltameter after passing through a normally-closed end of the double-channel analog switch. And the auxiliary MCU is configured to output a switch switching level signal to the dual-channel analog switch, control the I2C bus of the voltameter to be exclusively connected and switched with the auxiliary MCU or the main control chip, and control the startup and shutdown of the system mainboard according to the current voltage of the lithium battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery charging, in particular to a charging management system for lithium battery after over-discharge. BACKGROUND

[0002] Although the electronic device has the function of automatically shutting down when the battery is low, the battery over-discharge can be avoided. However, under the condition of shutting down, the static power consumption of the device will slowly consume the power of the lithium battery. Over time, the lithium battery is consumed and enters the over-discharge protection state, and the lithium battery has no output and the voltage value is zero.

[0003] At present, the charging integrated circuit without path management function is widely used, because the charging integrated circuit is easy to operate and low in cost. Figure 1 As shown in the figure, the charging IC (charging integrated circuit) without path management function is adopted, the maximum constant current charging current is 4A, and we set it to 3.2A (a certain margin is left), the general trickle charging is 1 / 10 of the constant current charging current (that is, the trickle charging current is 320mA), and the load (system mainboard) needs a current of 350mA for normal start, which is more than the trickle charging current. Assuming that the battery is over-discharged, because of over-discharge protection, there is no voltage output. At this time, after plugging in the adapter, the charging IC detects that the lithium battery voltage is lower than the trickle charging voltage, and the charging IC will output a trickle charging current of 320mA to charge the lithium battery. However, the existing load (system mainboard) configuration is to start after plugging in the adapter, and to show the user the charging state. At this time, the current Ic flows to the load to supply power to the system mainboard, and the lithium battery charging path Icharger has no current at all, and the lithium battery is not charged at all, resulting in the situation that the battery has almost no change in power for a long time and the battery cannot be charged. SUMMARY

[0004] The purpose of the present application is to provide a charging management system for lithium battery after over-discharge, to solve the technical problem that the battery cannot be charged or the charging speed is slow when the battery is over-discharged.

[0005] The application provides a charging management system for a lithium battery after overdischarge, which comprises a charging integrated circuit electrically connected with an adapter at an input end, a power meter electrically connected with the lithium battery, and an auxiliary MCU, wherein the output end of the charging integrated circuit is electrically connected with the lithium battery and a system mainboard, the auxiliary MCU is electrically connected with the adapter through a voltage stabilizer, the system mainboard comprises a main control chip, one GPIO port of the auxiliary MCU is connected with a high-level starting pin of the main control chip, the I2C bus of the auxiliary MCU is connected with the power meter through the always-on end of a double-channel analog switch, the main control chip is connected with the power meter through the always-closed end of the double-channel analog switch, and the auxiliary MCU is connected with the control end of the double-channel analog switch through another GPIO port.

[0006] In some embodiments, the I2C bus of the power meter is exclusively connected with the auxiliary MCU or the main control chip, and specifically comprises the following steps. After the auxiliary MCU is plugged in, the auxiliary MCU is self-started, a first switch switching level signal is output to the double-channel analog switch, and the I2C bus of the power meter is exclusively connected with the auxiliary MCU. If the voltage of the lithium battery is not lower than a starting voltage threshold, a second switch switching level signal is output to the double-channel analog switch, the I2C communication link between the auxiliary MCU and the power meter is disconnected, and the I2C communication link between the main control chip and the power meter is connected.

[0007] In some embodiments, the starting and shutdown of the system mainboard according to the voltage of the lithium battery specifically comprises the following steps. If the voltage of the lithium battery is lower than the starting voltage threshold, the auxiliary MCU outputs a shutdown level signal to the main control chip to control the main control chip to be shut down. If the voltage of the lithium battery is not lower than the starting voltage threshold, the auxiliary MCU outputs a starting level signal to the main control chip to control the main control chip to be started.

[0008] In some embodiments, a single-pole double-throw switch is arranged on the line connecting the external switch button of the system mainboard and the low-level starting pin of the main control chip, the enable end of the single-pole double-throw switch is connected with a GPIO port of the auxiliary MCU, the common end of the single-pole double-throw switch is connected with the low-level starting pin of the main control chip, and the line between the external switch button and the low-level starting pin is controlled to be connected or disconnected according to the control signal sent by the auxiliary MCU.

[0009] In some embodiments, a charging indicator light electrically connected to an auxiliary MCU is also included. When the system motherboard is in a powered-off state, if the battery charging current collected by the auxiliary MCU through reading the fuel gauge is greater than a threshold, the charging indicator light is turned on.

[0010] In some embodiments, the dual-channel analog switch includes two parallel single-pole double-throw (SPDT) switches. The control terminals of the two SPDT switches are connected together and then connected to the GPIO port of the auxiliary MCU. The normally closed terminals of the two SPDT switches are respectively connected to two signal lines of the I2C bus of the main control chip, and the normally open terminals of the two SPDT switches are respectively connected to two signal lines of the I2C bus of the auxiliary MCU. The common terminal of the two SPDT switches is respectively connected to two signal lines of the I2C bus of the fuel meter.

[0011] In some embodiments, the present invention further includes: Based on the undervoltage shutdown voltage, temperature compensation voltage, load compensation voltage, and battery health state compensation voltage of the system motherboard, the power-on voltage threshold is determined. The temperature compensation voltage is obtained by querying a preset temperature and compensation voltage table according to the battery temperature. The product of the system motherboard's maximum starting current and the line impedance is used as the load compensation voltage. The battery health state compensation voltage is obtained based on the difference between the system motherboard's maximum starting current, the current battery internal resistance, and the initial battery internal resistance. The undervoltage shutdown voltage, the system motherboard's maximum starting current, the line impedance, and the initial battery internal resistance are measured and stored in the flash memory of the auxiliary MCU before leaving the factory. The battery temperature and the current battery internal resistance are obtained by the auxiliary MCU through I2C reading of the fuel gauge. The current battery internal resistance is calculated by the fuel gauge after considering battery temperature compensation.

[0012] In some embodiments, obtaining the battery health state compensation voltage based on the difference between the system motherboard's maximum startup current, the current battery internal resistance, and the initial battery internal resistance specifically involves:

[0013] In the formula, The compensation voltage is for the healthy state. M is the maximum allowable compensation amplitude, which is a constant in volts (V). It is set according to the battery's maximum open-circuit voltage limit. It is the maximum startup current of the system motherboard, and it is the current internal resistance of the battery. is the initial battery internal resistance, 'a' is a constant controlling the compensation growth rate, and parameter 'b' is a constant used to control the acceleration point at which compensation begins. 'a' and 'b' are determined by fitting battery aging data. This item is used to ensure that the compensation value is 0 when the difference between the current battery internal resistance and the initial battery internal resistance is 0.

[0014] In some embodiments, the present invention further includes: If the ratio of the health state compensation voltage to M reaches a preset first proportion threshold, the auxiliary MCU sends a battery health warning prompt, and reaches a preset second proportion threshold, sends a battery replacement prompt, and prohibits starting the system mainboard.

[0015] The beneficial effects of the present application are as follows: the auxiliary MCU of the present application runs after being inserted into the adapter and controls the double-channel analog switch to realize switching of the I2C line; the auxiliary MCU reads the battery voltage collected by the electric quantity meter through the I2C bus, and controls the on-off of the system mainboard according to the current voltage of the battery, so as to realize closing of the system mainboard (load) when the voltage of the battery is very low after over-discharge, realize fast charging of the lithium battery by the adapter, and start the system mainboard when the voltage of the battery rises to a certain value, so as to realize the purpose of fast starting of the system mainboard immediately after meeting the starting condition. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0017] Figure 1 It is a principle block diagram of the existing charging device; Figure 2 It is a principle block diagram of the charging management device provided by the embodiment of the present application; Figure 3 It is a principle diagram of the double-channel analog switch; Figure 4 It is a principle diagram of the control external switch button; Figure 5 It is a system mainboard starting current waveform diagram. DETAILED DESCRIPTION

[0018] In order to make the person skilled in the art better understand the technical solutions in the present application, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0019] As Figure 2As shown, the application provides a charging management system for lithium battery after over-discharge, which comprises a charging integrated circuit electrically connected with an adapter at an input end, and a power meter electrically connected with the lithium battery, wherein the output end of the charging integrated circuit is electrically connected with the lithium battery and a system mainboard, and further comprises an auxiliary MCU, wherein the auxiliary MCU is electrically connected with the adapter through a voltage stabilizer, the system mainboard comprises a main control chip, one GPIO port of the auxiliary MCU is connected with a high level starting pin of the main control chip, the I2C bus of the auxiliary MCU is connected with the power meter after passing through the normally open end of a double-channel analog switch, the auxiliary MCU is connected with the control end of the double-channel analog switch through another GPIO port, and the I2C bus of the main control chip is connected with the power meter after passing through the normally closed end of the double-channel analog switch, wherein the auxiliary MCU is configured to output a switch switching level signal to the double-channel analog switch, and to control the I2C bus of the power meter to be exclusively connected with the auxiliary MCU or the main control chip, and to control the switching on and off of the system mainboard according to the current voltage of the lithium battery.

[0020] The auxiliary MCU of the application is inserted into the adapter and runs, and controls the double-channel analog switch to realize the switching of the I2C line, and when the adapter is not inserted for charging, the I2C bus of the power meter is exclusively connected with the main control chip, and the main control chip reads and displays the voltage and power.

[0021] When the adapter is inserted, the auxiliary MCU is powered on and self-starts, outputs a first switch switching level signal to the double-channel analog switch, and makes the I2C bus of the power meter be exclusively connected with the auxiliary MCU; if the voltage of the lithium battery is not lower than the starting voltage threshold, a second switch switching level signal is outputted to the double-channel analog switch, the I2C communication link between the auxiliary MCU and the power meter is disconnected, and the I2C communication link between the main control chip and the power meter is connected.

[0022] The auxiliary MCU reads the battery voltage collected by the power meter through the I2C bus, controls the switching on and off of the system mainboard according to the current voltage of the battery, so as to realize the closing of the system mainboard (load) when the battery voltage is very low, and realize the fast charging of the lithium battery by the adapter, and start the system mainboard when the voltage of the battery is up to a certain value, so as to realize the purpose of fast starting of the system mainboard immediately after the starting condition is met.

[0023] The auxiliary MCU of the application only runs when the adapter is inserted for charging each time, participates in the power monitoring, and does not run when the whole machine is not charging, so as not to increase the power consumption of the whole machine and affect the use time of the whole machine.

[0024] In some embodiments, the control of the switching on and off of the system mainboard according to the voltage of the lithium battery specifically comprises: If the voltage of the lithium battery is lower than the starting voltage threshold, the auxiliary MCU outputs a shutdown level signal to the main control chip to control the main control chip to shut down; If the voltage of the lithium battery is not lower than the starting voltage threshold, the auxiliary MCU outputs a starting level signal to the main control chip to control the main control chip to start.

[0025] In some embodiments, as shown in FIG. 1, an external switch button is connected to a low-level starting pin of the main control chip through a single-pole double-throw switch. Figure 4 The enable end of the single-pole double-throw switch is connected to a GPIO port of the auxiliary MCU, the common end of the single-pole double-throw switch is connected to the low-level starting pin of the main control chip, and the connection between the external switch button and the low-level starting pin is controlled according to the control signal sent by the auxiliary MCU.

[0026] The application can also limit the action of the external switch button of the user to avoid the user from starting the system mainboard by mistake when the battery voltage is insufficient for starting. The specific implementation is as described above, that is, a single-pole double-throw switch is arranged on the line connecting the original external switch button and the low-level starting pin of the main control chip.

[0027] The adapter or the lithium battery converts the voltage to 1.8V to supply power to the dual-channel analog switch and the single-pole double-throw switch, so that the dual-channel analog switch and the single-pole double-throw switch are always powered and can ensure that the switch chip is in a working state. If the adapter or the lithium battery is online, the one with higher voltage supplies power to the switch.

[0028] After the auxiliary MCU is started and detects that the battery voltage is lower than the starting voltage threshold through the power meter, the S signal of the single-pole double-throw switch is immediately controlled to be high, the signal C is switched to the A side (the always-on end), the external switch button is disconnected from the low-level starting pin of the main control chip, and the external switch button is disabled.

[0029] After the auxiliary MCU detects that the battery voltage is higher than the starting voltage threshold, the S signal of the single-pole double-throw switch is controlled to be low, the signal C is switched to the B side (the always-off end), the external switch button is connected to the low-level starting pin of the main control chip, and the external switch button is enabled.

[0030] In some embodiments, the application further includes a charging indicator lamp electrically connected to the auxiliary MCU. When the system mainboard is in the shutdown state, if the auxiliary MCU controls the charging indicator lamp to be turned on by reading the battery charging current collected by the power meter and determining that the battery charging current is greater than a threshold value. In the stage of charging the battery only by the adapter, the display screen on the system mainboard for displaying the power is temporarily not in a working state and cannot display the charging state. The application displays the charging state through the charging indicator lamp electrically connected to the auxiliary MCU.

[0031] In some embodiments, as shown in FIG. 1, an external switch button is connected to a low-level starting pin of the main control chip through a single-pole double-throw switch. Figure 3As shown, the double-channel analog switch includes two parallel single-pole double-throw switches, the control ends of the two single-pole double-throw switches are connected together and connected to the GPIO port of the auxiliary MCU, the normally closed ends of the two single-pole double-throw switches are respectively connected to two signal lines of the I2C bus of the main control chip, the normally open ends of the two single-pole double-throw switches are respectively connected to two signal lines of the I2C bus of the auxiliary MCU, and the common ends of the two single-pole double-throw switches are respectively connected to two signal lines of the I2C bus of the electric quantity meter.

[0032] In some embodiments, the start-up voltage threshold is determined based on an under-voltage shutdown voltage of a system mainboard, a temperature compensation voltage, a load compensation voltage and a state of health compensation voltage of a battery, the temperature compensation voltage is obtained by querying a preset compensation table of temperature and compensation voltage according to a battery temperature, the load compensation voltage is the product of a maximum start-up current of the system mainboard and a line impedance, and the state of health compensation voltage of the battery is obtained based on the maximum start-up current of the system mainboard, a current battery internal resistance and a difference between the initial battery internal resistance; the under-voltage shutdown voltage, the maximum start-up current of the system mainboard, the line impedance and the initial battery internal resistance are measured before leaving the factory and stored in a flash of an auxiliary MCU, the battery temperature and the current battery internal resistance are obtained by the auxiliary MCU through I2C reading of an electric quantity meter, and the current battery internal resistance is calculated by the electric quantity meter after considering the temperature compensation of the battery.

[0033] Specifically, the start-up voltage threshold is obtained by summing the under-voltage shutdown voltage, the temperature compensation voltage, the load compensation voltage and the state of health compensation voltage, and the specific formula is as follows:

[0034] In the formula, is the start-up voltage threshold, is the under-voltage shutdown voltage of the system mainboard, is the temperature compensation voltage, is the load compensation voltage, is the state of health compensation voltage.

[0035] The minimum voltage that enables the mainboard to start stably at 100% is called the under-voltage shutdown voltage, which is obtained through the mainboard chip manual and actual measurement. This is the minimum input voltage that enables the mainboard to work normally. If the voltage is lower than this value, the power supply chip (DC-DC converter) on the mainboard cannot output stable and correct voltage, which will cause the CPU, memory and other core devices to work abnormally or shut down.

[0036] The battery voltage is greatly affected by temperature. At low temperature, the battery internal resistance is high, and the voltage is high; at high temperature, the charging voltage needs to be limited to protect the battery. The temperature compensation voltage is obtained by querying a preset compensation table of temperature and compensation voltage according to the obtained battery temperature This compensation table is pre-stored in the flash of the auxiliary MCU.

[0037] Example: When the battery temperature is detected below 10°C, +0.2V (compensate for the false high voltage reading at low temperature, so that the battery can be charged more before starting the load); The maximum starting current of the system mainboard is measured before leaving the factory and stored in the flash of the auxiliary MCU. For example, Figure 5 In the laboratory, use a DC power supply analyzer in series with the power supply circuit of the system mainboard to collect the current waveform of the system mainboard of multiple sample machines from startup to completion of all core hardware initialization. Extract the maximum current value from the current waveform as the maximum starting current of the system mainboard. t0-t1 (surge peak): the moment the load switch is closed, a very high but very narrow current peak is generated to charge a large number of capacitors. The first peak often appears here. t1-t3 (hardware initialization): the CPU, memory, chipset, and other core hardware are powered on and initialized in turn, and the current quickly rises and reaches the global maximum. After t3 (stable platform period): the core hardware initialization is completed, the current falls from the peak and enters a stable state with relatively flat fluctuations.

[0038] The line impedance is a static, hardware design-determined physical parameter that refers to the total impedance of the line between the positive terminal of the battery and the input terminal of the system mainboard power supply. It can be obtained by measurement: use a four-wire milliohm meter to measure the resistance between the positive terminal of the battery and the input terminal of the mainboard power supply in the power-off state. The measured line impedance is directly written into the flash of the MCU as a constant.

[0039] The health state compensation voltage of the battery is obtained based on the maximum starting current of the system mainboard, the current battery internal resistance, and the difference between the initial battery internal resistance, and is specifically: M is the maximum allowed compensation amplitude, which is a constant with a unit of V, and is set according to the maximum open-circuit voltage limit of the battery to avoid the system from always not allowing the system mainboard to start up due to requiring a battery to reach an unattainable start-up voltage threshold; is the maximum starting current of the system mainboard, is the current battery internal resistance, is the initial battery internal resistance, a is a constant that controls the compensation growth rate, which is adjusted according to battery aging experimental data, and the initial data can be set as a=10 / M. Parameter b controls the constant of the compensation start acceleration point, which is determined according to the battery aging data fitting, for example, if the internal resistance difference reaches 0.05Ω when the aging starts to accelerate, set . to ensure that when the difference between the current battery internal resistance and the initial battery internal resistance is 0, the compensation value is 0.

[0040] In some embodiments, the present application also includes: If the health state compensation voltage If the ratio of the health state compensation voltage and M reaches a preset first proportion threshold, the auxiliary MCU sends a battery health warning prompt, and reaches a preset second proportion threshold to send a battery replacement prompt, and prohibits starting the system mainboard.

[0041] Specifically, a health degree index H can be defined based on the ratio of the health state compensation voltage and M, If H is less than the first proportion threshold, a battery health warning prompt is sent, and if H is less than the second proportion threshold, a battery replacement prompt is sent, and the system mainboard is prohibited from starting, and the first proportion threshold is higher than the second proportion threshold.

[0042] The above describes in detail the charging management system of the lithium battery after overdischarge. The principles and implementation manners of the present application are described by applying specific examples in this paper, and the above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0043] Each embodiment in the present application is described in a progressive manner, and the same and similar parts of each embodiment can be referred to each other. Each embodiment mainly describes the difference from other embodiments. Especially, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the related parts can be referred to the part of the description of the method embodiment.

Claims

1. A charging management system for lithium batteries after over-discharge, comprising a charging integrated circuit whose input terminal is electrically connected to an adapter, and a fuel gauge electrically connected to the lithium battery, wherein the output terminal of the charging integrated circuit is electrically connected to the lithium battery and a system motherboard, characterized in that: It also includes an auxiliary MCU, which is electrically connected to an adapter via a voltage regulator. The system motherboard includes a main control chip. One GPIO port of the auxiliary MCU is connected to the high-level start pin of the main control chip. The I2C bus of the auxiliary MCU is connected to the fuel gauge after passing through the normally open terminal of the dual-channel analog switch. The auxiliary MCU is connected to the control terminal of the dual-channel analog switch through another GPIO port. The I2C bus of the main control chip is connected to the fuel gauge after passing through the normally closed terminal of the dual-channel analog switch. The auxiliary MCU is configured to output a switch switching level signal to the dual-channel analog switch to control the exclusive connection switching between the fuel gauge's I2C bus and the auxiliary MCU or the main control chip, and to control the power on / off of the system motherboard according to the current voltage of the lithium battery.

2. The charging management system for lithium batteries after over-discharge according to claim 1, characterized in that, The exclusive connection switching between the I2C bus controlling the fuel gauge and the auxiliary MCU or main control chip specifically includes: The auxiliary MCU starts automatically after being plugged in and outputs the first switch switching level signal to the dual-channel analog switch, so that the I2C bus of the fuel meter is exclusively connected to the auxiliary MCU. If the lithium battery voltage is not lower than the power-on voltage threshold, output the second switch switching level signal to the dual-channel analog switch, disconnect the I2C communication link between the auxiliary MCU and the fuel gauge, and connect the I2C communication link between the main control chip and the fuel gauge.

3. The charging management system for lithium batteries after over-discharge according to claim 1, characterized in that, The power-on / off control of the mainboard based on the lithium battery voltage specifically includes: If the lithium battery voltage is lower than the power-on voltage threshold, the auxiliary MCU outputs a power-off level signal to the main control chip to control the main control chip to power off. If the lithium battery voltage is not lower than the power-on voltage threshold, the auxiliary MCU outputs a power-on level signal to the main control chip to control the main control chip to power on.

4. The charging management system for lithium batteries after over-discharge according to claim 1, characterized in that, A single-pole double-throw switch is installed on the line connecting the external switch button on the system motherboard and the low-level start pin of the main control chip. The enable terminal of the single-pole double-throw switch is connected to a GPIO port of the auxiliary MCU, and the common terminal of the single-pole double-throw switch is connected to the low-level start pin of the main control chip. According to the control signal issued by the auxiliary MCU, the connection and disconnection of the line between the external switch button and the low-level start pin are controlled.

5. The charging management system for lithium batteries after over-discharge according to claim 1, characterized in that, It also includes a charging indicator light that is electrically connected to the auxiliary MCU. When the system motherboard is powered off, if the battery charging current collected by the auxiliary MCU through the fuel gauge is greater than the threshold, the charging indicator light will be turned on.

6. The charging management system for lithium batteries after over-discharge according to claim 1, characterized in that, The dual-channel analog switch includes two parallel single-pole double-throw (SPDT) switches. The control terminals of the two SPDT switches are connected together and then connected to the GPIO port of the auxiliary MCU. The normally closed terminals of the two SPDT switches are respectively connected to two signal lines of the I2C bus of the main control chip, and the normally open terminals of the two SPDT switches are respectively connected to two signal lines of the I2C bus of the auxiliary MCU. The common terminal of the two SPDT switches is respectively connected to two signal lines of the I2C bus of the fuel meter.

7. The charging management system for lithium batteries after over-discharge according to claim 2, characterized in that, Also includes: Based on the undervoltage shutdown voltage, temperature compensation voltage, load compensation voltage, and battery health state compensation voltage of the system motherboard, the power-on voltage threshold is determined. The temperature compensation voltage is obtained by querying a preset temperature and compensation voltage table according to the battery temperature. The product of the system motherboard's maximum starting current and the line impedance is used as the load compensation voltage. The battery health state compensation voltage is obtained based on the difference between the system motherboard's maximum starting current, the current battery internal resistance, and the initial battery internal resistance. The undervoltage shutdown voltage, the system motherboard's maximum starting current, the line impedance, and the initial battery internal resistance are measured and stored in the flash memory of the auxiliary MCU before leaving the factory. The battery temperature and the current battery internal resistance are obtained by the auxiliary MCU through I2C reading of the fuel gauge. The current battery internal resistance is calculated by the fuel gauge after considering battery temperature compensation.

8. The charging management system for lithium batteries after over-discharge according to claim 7, characterized in that, The method for obtaining the battery health state compensation voltage based on the system motherboard's maximum startup current, the current battery internal resistance, and the difference between the initial battery internal resistance is as follows: In the formula, For the compensation voltage under healthy conditions, M is the maximum allowable compensation amplitude, which is a constant and its unit is V. It is the maximum startup current of the system motherboard. This is the current internal resistance of the battery. is the initial battery internal resistance, 'a' is a constant that controls the compensation growth rate, and parameter 'b' is a constant used to control the acceleration point at which compensation begins. 'a' and 'b' are determined by fitting battery aging data.

9. The charging management system for lithium batteries after over-discharge according to claim 8, characterized in that, Also includes: If the ratio of the health status compensation voltage to M reaches the preset first proportional threshold, the auxiliary MCU will issue a battery health warning. If it reaches the preset second proportional threshold, it will issue a battery replacement prompt and prevent the system motherboard from starting.

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