Battery protection chip and battery protection system

Abstract

The application discloses a battery protection chip and a battery protection system, and relates to the technical field of battery protection, in particular to a battery protection chip and a battery protection system. The battery protection chip comprises a power switch tube module, a basic function module and a battery voltage collection and operation device. The battery voltage collection and operation device is used for taking the potential of the positive input end of the chip as a reference, proportionally scaling the voltage between the positive detection end and the negative detection end, and outputting a voltage detection signal from the detection end. In the application, the selected reference potential is not affected by the voltage drop of the parasitic diode of the MOS tube in the power switch tube module, so that the voltage sampling deviation in the overcharge protection state is effectively eliminated, and the accurate collection of the battery voltage is realized.

Description

Technical Field

[0001] This invention belongs to the field of battery protection technology, and in particular relates to a battery protection chip and a battery protection system. Background Technology

[0002] Lithium-ion batteries, with their high energy density and long cycle life, are widely used in power banks, portable digital products, and small energy storage devices. Current mainstream lithium battery safety management solutions typically employ a hardware protection circuit composed of a lithium battery protection IC and a charge / discharge control MOSFET. This circuit monitors the battery cell voltage in real time and quickly cuts off the circuit when the voltage exceeds the limit, preventing safety hazards such as bulging and thermal runaway caused by overcharging, over-discharging, and overcurrent. However, the officially implemented national standard "Technical Specification for Safety of Mobile Batteries GB 47372-2026" (hereinafter referred to as the "New National Standard") explicitly requires in Chapter 6.8, the intelligent management clause, that after overcharging is triggered, the system must accurately collect and record real-time data on the voltage exceeding the upper limit of the charging voltage for a single battery cell, and must store the most unfavorable voltage value at one-hour intervals during overcharging. This imposes mandatory requirements on the accuracy of voltage collection under overcharging conditions.

[0003] While existing lithium battery protection architectures generally yield results consistent with battery voltage under normal operating conditions, parasitic diode voltage drops occur in the MOSFETs of the power switching module after overcharge protection is triggered. This causes the sampled signal to deviate from the battery voltage, failing to meet the data recording requirements of the new national standard. Therefore, there is an urgent need to develop a novel circuit solution that, while retaining the basic overcharge and over-discharge hardware protection functions of the original protection IC, can effectively avoid parasitic diode voltage drop interference and achieve accurate battery voltage acquisition under overcharge conditions. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a battery protection chip and a battery protection system.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A battery protection chip, the chip having a positive input terminal, a negative input terminal, a voltage output terminal, and a detection terminal, the chip comprising: The power switching transistor module has its first connection terminal connected to the negative input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the positive input terminal of a chip, its negative detection terminal connected to the negative input terminal of a chip, and its processing output terminal connected to the voltage output terminal of a chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the positive input terminal of the chip as a reference, and then output a voltage detection signal from the detection terminal.

[0006] A battery protection chip, the chip having a positive input terminal, a negative input terminal, a cascade connection terminal, a voltage output terminal, and a detection terminal, the chip comprising: The power switching transistor module has its first connection terminal connected to the negative input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the positive input terminal of a chip, its negative detection terminal connected to the cascade connection terminal of the chip, and its processing output terminal connected to the voltage output terminal of the chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the positive input terminal of the chip as a reference, and then output a voltage detection signal from the voltage output terminal.

[0007] A battery protection chip, the chip having a positive input terminal, a negative input terminal, a voltage output terminal, and a detection terminal, the chip comprising: A power switching transistor module has a first connection terminal connected to the positive input terminal of the chip and a second connection terminal connected to the detection terminal of the chip. A basic functional module has a first and second detection terminal connected to the positive and negative input terminals of the chip, respectively, and a third and fourth detection terminal connected to the first and second connection terminals of the power switching transistor module, respectively. A drive output terminal is connected to the controlled terminal of the power switching transistor module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive and negative input terminals, and to detect overcurrent and short circuit of the battery based on the voltage difference across the power switching transistor module. When an abnormality is detected, the module is controlled to shut down. A battery voltage acquisition and processing unit has its positive detection terminal connected to the positive input terminal of a chip, its negative detection terminal connected to the negative input terminal of a chip, and its processing output terminal connected to the voltage output terminal of a chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the negative input terminal of the chip as a reference, and then output a voltage detection signal from the detection terminal.

[0008] A battery protection chip, the chip having a positive input terminal, a negative input terminal, a cascade connection terminal, a voltage output terminal, and a detection terminal, the chip comprising: The power switching transistor module has its first connection terminal connected to the positive input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the cascade connection terminal of a chip, its negative detection terminal connected to the negative input terminal of the chip, and its processing output terminal connected to the voltage output terminal of the chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the negative input terminal of the chip as a reference, and then output a voltage detection signal from the voltage output terminal.

[0009] Furthermore, the battery voltage acquisition and processing unit includes an operational amplifier OP1, resistors R6 and R7; the positive power supply terminal of the operational amplifier OP1 is electrically connected to the positive detection terminal, and the negative power supply terminal of the operational amplifier OP1 is electrically connected to the negative detection terminal; the non-inverting input terminal of the operational amplifier OP1 is electrically connected to the positive detection terminal through resistor R6, and the non-inverting input terminal of the operational amplifier OP1 is also electrically connected to the negative detection terminal through resistor R7; the inverting input terminal of the operational amplifier OP1 is electrically connected to its output terminal, and the output terminal of the operational amplifier OP1 is electrically connected to the voltage output terminal.

[0010] Furthermore, by adjusting the resistance ratio of resistors R6 and R7, the scaling factor of the battery voltage acquisition and processing unit can be adjusted.

[0011] A battery protection system includes a battery protection chip and a first MCU unit. The positive input terminal of the battery protection chip is electrically connected to the positive terminal of the battery, and the negative input terminal of the battery protection chip is electrically connected to the negative terminal of the battery. The detection terminal of the battery protection chip is connected to the ground terminal of the first MCU unit, and the voltage output terminal of the battery protection chip is electrically connected to the first input / output terminal of the first MCU unit. The power supply input terminal of the first MCU unit is electrically connected to the positive terminal of the battery. The first MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and its power supply input terminal.

[0012] A battery protection system includes two or more battery protection chips connected in series and a second MCU unit. The positive input terminal of each battery protection chip and the power supply input terminal of the second MCU unit are both electrically connected to the positive terminal of the battery. The negative input terminal and cascade connection terminal of the first-stage battery protection chip are both electrically connected to the negative terminal of the battery. The negative input terminals of each subsequent battery protection chip are electrically connected to the detection terminal of the preceding battery protection chip, and the cascade connection terminal is electrically connected to the voltage output terminal of the preceding battery protection chip. The detection terminal of the last-stage battery protection chip is electrically connected to the ground terminal of the second MCU unit, and the voltage output terminal is electrically connected to the first input / output terminal of the second MCU unit. The second MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and its power supply input terminal.

[0013] A battery protection system includes a battery protection chip and a third MCU unit. The positive input terminal of the battery protection chip is electrically connected to the positive terminal of the battery, and the negative input terminal of the battery protection chip is electrically connected to the negative terminal of the battery. The detection terminal of the battery protection chip is electrically connected to the power supply input terminal of the third MCU unit, and the voltage output terminal of the battery protection chip is electrically connected to the first input / output terminal of the third MCU unit. The ground terminal of the third MCU unit is electrically connected to the negative terminal of the battery. The third MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and the ground terminal.

[0014] A battery protection system includes two or more battery protection chips connected in series and a fourth MCU unit; the negative input terminal of each battery protection chip and the ground terminal of the fourth MCU unit are both electrically connected to the negative terminal of the battery; the positive input terminal and the cascade connection terminal of the first-stage battery protection chip are both electrically connected to the positive terminal of the battery; the positive input terminal of each subsequent battery protection chip is electrically connected to the detection terminal of the preceding battery protection chip, and the cascade connection terminal is electrically connected to the voltage output terminal of the preceding battery protection chip; the detection terminal of the last-stage battery protection chip is electrically connected to the power supply input terminal of the fourth MCU unit, and the voltage output terminal of the last-stage battery protection chip is electrically connected to the first input / output terminal of the fourth MCU unit; the fourth MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and the ground terminal.

[0015] In this invention, the battery voltage acquisition and calculation unit uses the potential of the positive or negative terminal of the battery as a reference for voltage scaling. The MCU unit uses the same reference potential (positive for negative terminal protection, negative for positive terminal protection) to calculate the battery voltage. Since the selected reference potential is not affected by the voltage drop of the parasitic diode in the MOSFET module of the power switch, sampling deviation can be effectively eliminated. Using a resistor voltage divider structure, high-precision scaling can be achieved while adjusting the battery high voltage to within the MCU sampling range. Furthermore, the circuit architecture of this invention does not require modification of the original protection IC hardware circuitry, and multi-level chips can be connected in series through cascading connections. Signals can be directly extracted from any level of chip to calculate the battery voltage, resulting in strong versatility and low modification costs. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a structural block diagram of a battery negative terminal protection system in the prior art.

[0017] Figure 2 This is a structural block diagram of a battery positive terminal protection system in the prior art.

[0018] Figure 3 This is a structural block diagram of an embodiment of the battery protection chip of the present invention.

[0019] Figure 4 This is the circuit diagram of the battery voltage acquisition and processing unit.

[0020] Figure 5 This is a structural block diagram of an embodiment of the battery protection system of the present invention.

[0021] Figure 6 This is a structural block diagram of another embodiment of the battery protection chip of the present invention.

[0022] Figure 7 This is a structural block diagram of another embodiment of the battery protection system of the present invention.

[0023] Figure 8 This is a structural block diagram of another embodiment of the battery protection chip of the present invention.

[0024] Figure 9 This is a structural block diagram of another embodiment of the battery protection system of the present invention.

[0025] Figure 10 This is a structural block diagram of another embodiment of the battery protection chip of the present invention.

[0026] Figure 11 This is a structural block diagram of another embodiment of the battery protection system of the present invention. Detailed Implementation

[0027] The following specific examples illustrate the implementation of the present invention. The illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0028] Please see Figure 1 Currently, mainstream lithium battery negative terminal protection solutions on the market can be divided into single-string discrete protection IC solutions, single-string two-in-one lithium battery negative terminal protection IC solutions, and multi-string discrete protection IC solutions according to their architecture. Under normal battery charging and discharging conditions, the NMOS transistor remains in the conducting state, and the MCU unit directly samples the voltage across the battery cell via P+ and P-. The voltage acquisition result is basically consistent with the battery voltage, which can meet the normal voltage sampling requirements. However, under overcharge protection triggering scenarios, all existing protection architectures have inherent circuit defects and cannot achieve accurate battery voltage acquisition, making it difficult to meet the mandatory requirements of the new national standard for intelligent management.

[0029] In the application scenario of single-string discrete lithium battery negative terminal protection IC, the upper limit voltage of the battery cell for normal charging is generally 4.2V, and the output voltage of the matching charger is usually 5V. When the battery charging voltage exceeds the limit and triggers overcharge protection, the control pin output level of the protection IC jumps, driving the controlled NMOS transistor to turn off to cut off the main charging circuit. After the charging circuit is disconnected, the charger side voltage continues to act on the P- pin of the protection board, directly pulling the P- potential down to a negative voltage. Under typical operating conditions, the negative voltage can reach -0.8V. At this time, the NMOS transistor itself has a parasitic diode to maintain the potential conduction path of the circuit. During the process of the MCU unit collecting voltage through P+ and P-, the sampling circuit will superimpose the fixed voltage drop of the parasitic diode. Finally, the sampling voltage obtained by the MCU unit is the difference between the battery voltage and the voltage drop of the parasitic diode. The sampling value deviates from the battery voltage and cannot accurately capture the over-limit voltage of the battery at the moment of overcharging. It cannot accurately store the overcharge voltage data as required by the new national standard.

[0030] For a single-string dual-cell lithium battery negative terminal protection IC, due to overcharge protection, the P- terminal is also pulled down to a negative voltage by the charger, and the parasitic diode is switched to the charging-disabled direction. Therefore, a parasitic diode voltage still exists, causing the MCU to be unable to accurately read the battery voltage.

[0031] The multi-string discrete lithium battery negative terminal protection IC is composed of multiple sets of single-string discrete protection units cascaded together. The protection branch circuit topology, overcharge protection action logic, and sampling error mechanism caused by NMOS parasitic diodes for a single battery cell are exactly the same as those of the single-string discrete scheme. The technical drawbacks of the corresponding branch P- negative voltage and parasitic diode voltage drop interference sampling after overcharge triggering also exist simultaneously.

[0032] Therefore, the current industry-used single-string discrete and multi-string discrete lithium battery negative terminal protection IC architectures are all affected by the P-negative voltage and NMOS parasitic diode voltage drop after overcharge protection takes effect. This results in distorted MCU voltage sampling data, making it impossible to accurately obtain the battery overcharge voltage parameters and failing to meet the mandatory specifications for overcharge voltage recording and extreme value storage in the new national standard.

[0033] Please see Figure 2In current mainstream lithium battery positive terminal protection schemes, the power switch module is placed in the connection path between the battery's positive terminal and the MCU unit's power input terminal. The protection IC's power output terminal V+ is electrically connected to the MCU unit's power input terminal P+. Under normal charging and discharging conditions, the PMOS transistor remains in the conducting state, and the MCU unit directly samples the voltage across the battery cell via P+ and P-, with the sampled value being basically consistent with the battery voltage. However, in overcharge protection trigger scenarios, the protection IC controls the PMOS transistor to turn off to cut off the main charging circuit, causing a voltage drop in the parasitic diode of the PMOS transistor. When the MCU unit samples the voltage via P+ and P-, this parasitic diode voltage drop is superimposed, resulting in a sampled value that deviates from the battery voltage. Consequently, it is impossible to accurately obtain the battery's over-limit voltage at the moment of overcharging.

[0034] Example 1 Please see Figure 3 , Figure 3 This is a structural block diagram of an embodiment of the battery protection chip of the present invention. The battery protection chip in this embodiment is a negative-terminal protection architecture battery protection chip, which has a positive input terminal VDD, a negative input terminal VSS, a voltage output terminal AOUT, and a detection terminal VM. The chip includes a power switch module, a basic function module, and a battery voltage acquisition and processing unit.

[0035] The first connection terminal of the power switch module is connected to the negative input terminal VSS of the chip, and the second connection terminal is connected to the detection terminal VM of the chip. The power switch module can be a single NMOS transistor or multiple NMOS transistors connected in series. For example, when the power switch module uses two NMOS transistors, the two NMOS transistors can be connected in series back-to-back in a source-to-source configuration. The drains of the two NMOS transistors serve as the first and second connection terminals of the power switch module, respectively, and the gates of the two NMOS transistors serve as the controlled terminals of the power switch module, connected to the basic functional module. Thus, the charging circuit and the discharging circuit can be controlled separately by the two NMOS transistors.

[0036] The basic functional module is used to implement the basic protection functions of the battery protection chip. The basic functional module has a first detection terminal, a second detection terminal, a third detection terminal, a fourth detection terminal, and a drive output terminal. The first and second detection terminals of the basic functional module are respectively connected to the positive input terminal VDD and the negative input terminal VSS of the chip, used to detect overcharge and over-discharge of the battery. The third and fourth detection terminals of the basic functional module are respectively connected to the first and second connection terminals of the power switch module (i.e., the negative input terminal VSS and the detection terminal VM of the chip), used to detect overcurrent and short circuit of the battery. The drive output terminal of the basic functional module is connected to the controlled terminal of the power switch module, used to control the power switch module to shut down when an abnormality is detected.

[0037] Specifically, the basic functional module includes an overcharge and over-discharge detection circuit, an overcurrent and short-circuit detection circuit, and a logic processing drive circuit. The two detection terminals of the overcharge and over-discharge detection circuit are respectively connected to the positive input terminal VDD and the negative input terminal VSS of the chip, and its output terminal is connected to the first input terminal of the logic processing drive circuit, which is used to send a first protection signal to the logic processing drive circuit when an overcharge or over-discharge phenomenon is detected.

[0038] The two detection terminals of the overcurrent and short-circuit detection circuit are respectively connected to the first and second connection terminals of the power switching module, and its output terminal is connected to the second input terminal of the logic processing drive circuit. This circuit sends a second protection signal to the logic processing drive circuit when an overcurrent or short circuit is detected. The output terminal of the logic processing drive circuit is connected to the controlled terminal of the power switching module, and is used to turn off the power switching module upon receiving either the first or second protection signal.

[0039] Since the overcharge and over-discharge detection circuit, the overcurrent and short-circuit detection circuit, and the logic processing drive circuit all use the potential at the negative input terminal VSS of the chip as the internal reference ground, the overcurrent and short-circuit detection circuit can also be connected to the negative input terminal VSS of the chip by connecting the internal reference ground.

[0040] The battery voltage acquisition and processing unit has a positive detection terminal VBAT+, a negative detection terminal VBAT-, and a processing output terminal VOUT. The positive detection terminal VBAT+ is connected to the positive input terminal VDD of the chip, the negative detection terminal VBAT- is connected to the negative input terminal VSS of the chip, and the processing output terminal VOUT is connected to the voltage output terminal AOUT of the chip. The battery voltage acquisition and processing unit uses the potential of the positive input terminal VDD of the chip as a reference, scales the voltage between the positive detection terminal VBAT+ and the negative detection terminal VBAT-, and outputs a voltage detection signal from its processing output terminal VOUT.

[0041] Please see Figure 4The battery voltage acquisition and processing unit can acquire the battery voltage using a computational circuit structure, and then scale down the battery voltage value proportionally to adapt to the sampling range of the external MCU unit. The battery voltage acquisition and processing unit may include an operational amplifier OP1, resistors R6 and R7. The positive power supply terminal of the operational amplifier OP1 is electrically connected to the positive detection terminal VBAT+, and the negative power supply terminal of the operational amplifier OP1 is electrically connected to the negative detection terminal VBAT-. The non-inverting input terminal of the operational amplifier OP1 is electrically connected to the positive detection terminal VBAT+ through resistor R6, and the non-inverting input terminal of the operational amplifier OP1 is also electrically connected to the negative detection terminal VBAT- through resistor R7. The inverting input terminal of the operational amplifier OP1 is electrically connected to its output terminal, and the output terminal of the operational amplifier OP1 is electrically connected to the operational output terminal VOUT.

[0042] The relationship between the output voltage and input voltage of the above circuit is as follows: V OUT = (V BAT+ -V BAT- )×[R7 / (R6+R7)] In the formula, V OUT V represents the output voltage of operational amplifier OP1. BAT+ This represents the potential of the positive detection terminal VBAT+; V BAT- This indicates the potential of the negative detection terminal VBAT-; R6 and R7 are the resistance values ​​of resistors R6 and R7, respectively.

[0043] Therefore, the scaling factor P of the battery voltage acquisition and processing unit is calculated using the following formula: P = R7 / (R6 + R7) When R6 = R7, P = 1 / 2, V OUT = 1 / 2×(V BAT+ -V BAT- ).

[0044] By adjusting the values ​​of resistors R6 and R7, the scaling factor P of the battery voltage acquisition arithmetic unit can be adjusted, ensuring that the output voltage of operational amplifier OP1 is within a predetermined voltage range (i.e., the voltage range of the external MCU unit). For example, by adjusting the values ​​of resistors R6 and R7, the output voltage of operational amplifier OP1 can be made no greater than 3.0V, thus ensuring that the output voltage of operational amplifier OP1 is less than the maximum voltage range of the MCU unit (3.3V). This embodiment can be used in both single-cell and multi-cell lithium battery protection circuits.

[0045] Example 2 Please see Figure 5 , Figure 5This is a structural block diagram of an embodiment of the battery protection system of the present invention. The battery protection system of this embodiment is a battery negative terminal protection system, including a battery protection chip and a first MCU unit. The battery protection chip adopts the battery protection chip of Embodiment 1.

[0046] The positive input terminal VDD of the battery protection chip is electrically connected to the positive terminal of the battery, the negative input terminal VSS is electrically connected to the negative terminal of the battery, the voltage output terminal AOUT is electrically connected to the first input / output terminal I / O1 of the first MCU unit, and the detection terminal VM is electrically connected to the ground terminal GND of the first MCU unit. The power supply input terminal P+ of the first MCU unit is electrically connected to the positive terminal of the battery.

[0047] In this embodiment, the positive detection terminal VBAT+ of the battery voltage acquisition and processing unit is electrically connected to the positive terminal of the battery through the positive input terminal VDD of the battery protection chip, and the negative detection terminal VBAT- of the battery voltage acquisition and processing unit is electrically connected to the negative terminal of the battery through the negative input terminal VSS of the battery protection chip. Therefore, the battery voltage acquisition and processing unit will proportionally scale the voltage between the positive and negative terminals of the battery and output a voltage detection signal from the processing output terminal VOUT. For example, when P=1 / 2, the voltage difference between the voltage detection signal and the positive terminal of the battery is half of the battery voltage.

[0048] Since the voltage detection signal in this embodiment is calculated with the positive potential of the battery as a reference, and the power supply input terminal P+ of the first MCU unit is also connected to the positive terminal of the battery, the first MCU unit can also use the positive potential of the battery as a reference to accurately calculate the battery voltage based on the voltage difference between its first input / output terminal I / O1 and the power supply input terminal P+.

[0049] The working principle of this embodiment is as follows: In overcharge protection trigger scenarios, when the battery charging voltage exceeds the limit and triggers overcharge protection, the basic function module controls the NMOS transistor in the power switching module to turn off to disconnect the main charging circuit. At this time, the charger side voltage continuously acts on the P- terminal of the protection system (i.e., the ground terminal GND of the first MCU unit), pulling the P- potential down to a negative voltage, causing a voltage drop in the parasitic diode of the NMOS transistor. However, since the chip's detection terminal VM is directly connected to the ground terminal GND of the first MCU unit, and the voltage detection signal output by the battery voltage acquisition and calculation unit uses the chip's positive input terminal VDD as a reference, the first MCU unit calculates the battery voltage based on the voltage difference between the VDD potential (i.e., the battery positive terminal potential) and the voltage detection signal at the AOUT terminal. The VDD terminal potential is the battery positive terminal voltage and is not affected by the negative voltage at the P- terminal or the parasitic diode voltage drop, thus accurately reflecting the battery voltage. Based on this voltage detection signal, the first MCU unit can accurately calculate the battery voltage, completing the accurate acquisition and storage of the overcharge voltage.

[0050] This embodiment can also employ a multi-stage battery protection chip series structure. For example, the voltage output terminal AOUT of the first-stage battery protection chip connected to the battery can be electrically connected to the first input / output terminal I / O1 of the first MCU unit, while the voltage output terminals AOUT of the other stages of the battery protection chip are not connected. Since the voltage detection signal output by the first-stage battery protection chip is not affected by negative voltage and parasitic diode voltage drop, the battery voltage can be accurately acquired. Alternatively, the first-stage battery protection chip can be configured to only perform overcharge protection. In this case, it can be ensured that the first-stage battery protection chip will not activate protection before the second-stage battery protection chip. Therefore, the voltage output terminal AOUT of the first-stage battery protection chip can also be disconnected, and the voltage output terminal AOUT of the second-stage battery protection chip can be electrically connected to the first input / output terminal I / O1 of the first MCU unit, which will also allow for accurate acquisition of the battery voltage.

[0051] In this embodiment, the voltage is calculated using the battery's positive terminal potential as a reference. After overcharge protection is triggered, even if the P- terminal is pulled down to a negative voltage and the NMOS transistor's parasitic diode generates a voltage drop, the battery's positive terminal potential is unaffected by the aforementioned interference. Therefore, the voltage calculated by the first MCU unit is the battery voltage, effectively eliminating sampling deviation. This embodiment does not require modification of the original protection IC's hardware protection circuitry, has strong compatibility, low modification costs, and meets the mandatory requirements of the new national standard.

[0052] Example 3 Please see Figure 6 , Figure 6 This is a structural block diagram of another embodiment of the battery protection chip. The battery protection chip in this embodiment is a negative-terminal protection architecture battery protection chip, which has a positive input terminal VDD, a negative input terminal VSS, a cascade connection terminal AIN, a voltage output terminal AOUT, and a detection terminal VM. The chip includes a power switch module, a basic functional module, and a battery voltage acquisition and processing unit.

[0053] The first connection terminal of the power switch module is connected to the negative input terminal VSS of the chip, and the second connection terminal is connected to the detection terminal VM of the chip. The power switch module can be one or more NMOS transistors connected in series. The structure of the basic functional module is the same as that in Embodiment 1, and will not be described again here.

[0054] The battery voltage acquisition and processing unit has a positive detection terminal VBAT+, a negative detection terminal VBAT-, and a processing output terminal VOUT. The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit is connected to the positive input terminal VDD of the chip, the negative detection terminal VBAT- is connected to the cascade connection terminal AIN of the chip, and the processing output terminal VOUT is connected to the voltage output terminal AOUT of the chip.

[0055] The battery voltage acquisition and processing unit is used to scale the voltage between the positive detection terminal VBAT+ and the negative detection terminal VBAT-, and then output a voltage detection signal from the processing output terminal VOUT. Compared with Embodiment 1, this embodiment only adds a cascade connection terminal AIN to the chip, and replaces the negative detection terminal VBAT- of the battery voltage acquisition and processing unit with the cascade connection terminal AIN connected to the chip. The specific circuit structure of the battery voltage acquisition and processing unit is the same as that of Embodiment 1, and will not be described again here.

[0056] Example 4 Please see Figure 7 , Figure 7 This is a structural block diagram of another embodiment of the battery protection system of the present invention. The battery protection system of this embodiment is a battery negative terminal protection system, including two or more battery protection chips connected in series and a second MCU unit. The battery protection chip adopts the battery protection chip of embodiment 3.

[0057] The positive input terminal VDD of each stage of the battery protection chip and the power supply input terminal P+ of the second MCU unit are both electrically connected to the positive terminal of the battery. The negative input terminal VSS and the cascade connection terminal AIN of the first-stage battery protection chip are both electrically connected to the negative terminal of the battery. The negative input terminal VSS of each subsequent stage of the battery protection chip is electrically connected to the detection terminal VM of the previous stage's battery protection chip, and the cascade connection terminal AIN is electrically connected to the voltage output terminal AOUT of the previous stage's battery protection chip. The detection terminal VM of the last stage of the battery protection chip is electrically connected to the ground terminal GND of the second MCU unit, and the voltage output terminal AOUT is electrically connected to the first input / output terminal I / O1 of the second MCU unit.

[0058] This embodiment uses a two-stage series-connected battery protection chip as an example. The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit of the first-stage battery protection chip U1 is electrically connected to the positive terminal of the battery through the chip's positive input terminal VDD, and the negative detection terminal VBAT- is electrically connected to the negative terminal of the battery through the chip's cascade connection terminal AIN. Therefore, the battery voltage acquisition and processing unit of the first-stage battery protection chip U1 will proportionally scale the voltage between the positive and negative terminals of the battery and output a first voltage detection signal from its processing output terminal VOUT to the cascade connection terminal AIN of the second-stage battery protection chip U2.

[0059] The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit of the second-stage battery protection chip U2 is still connected to the positive terminal of the battery, while the negative detection terminal VBAT- is connected to the voltage output terminal AOUT of the first-stage battery protection chip U1. It further scales the difference between the first voltage detection signal and the battery's positive terminal voltage to output a second voltage detection signal. This process is repeated stage by stage, with each chip sequentially scaling the voltage signal. Ultimately, the voltage detection signal received by the second MCU unit is the battery voltage value after multiple scaling stages.

[0060] For example, when P=1 / 2, the voltage difference between the first voltage detection signal output by the first-stage battery protection chip U1 and the positive terminal of the battery is half the battery voltage, and the voltage difference between the second voltage detection signal output by the second-stage battery protection chip U2 and the positive terminal of the battery is 1 / 4 of the battery voltage. Of course, since the battery voltage in this embodiment undergoes multiple scaling stages, to avoid the input voltage to the second MCU unit being too low, the scaling factor P of the battery voltage acquisition and processing unit can be appropriately increased.

[0061] Since the voltage detection signals at each level are obtained with reference to the positive terminal potential of the battery, and the power supply input terminal P+ of the second MCU unit is also connected to the positive terminal of the battery, the second MCU unit can accurately calculate the battery voltage based on the voltage difference between its first input / output terminal I / O1 and the power supply input terminal P+, with reference to the positive terminal potential of the battery.

[0062] The working principle of this embodiment is as follows: In the overcharge protection trigger scenario, the basic functional module controls the NMOS transistor in the power switch module to turn off to cut off the main charging circuit. At this time, the charger side voltage pulls the potential of the P- terminal (i.e., the ground terminal GND of the second MCU unit) down to a negative voltage, and the parasitic diode of the NMOS transistor generates a voltage drop. However, in this embodiment, each stage of the battery voltage acquisition and calculation unit scales the voltage between the battery positive terminal and the corresponding detection point proportionally. The power supply input terminal P+ of the second MCU unit is connected to the battery positive terminal, enabling the second MCU unit to perform voltage inverse calculation with the battery positive terminal potential as a reference. Since the battery positive terminal potential is not affected by the negative voltage of the P- terminal and the voltage drop of the parasitic diode, the voltage calculated by the second MCU unit can truly reflect the battery voltage, completing the accurate acquisition and storage of the overcharge voltage.

[0063] In this embodiment, based on Embodiments 1 and 2, a multi-level chip series connection is achieved by adding a cascade connection terminal AIN. Each level is scaled proportionally with the positive terminal potential of the battery as a reference. The circuits of each level are not affected by the negative voltage of the P- terminal and the voltage drop of the parasitic diode. Thus, the voltage signal can be directly extracted from any level of battery protection chip and the battery voltage can be accurately calculated accordingly. There is no need to limit the detection signal to be taken out from a specific cascade position, which reduces the constraints of system wiring. It can be widely used in series protection scenarios and has strong scalability.

[0064] Example 5 Please see Figure 8 , Figure 8 This is a structural block diagram of another embodiment of the battery protection chip of the present invention. The battery protection chip in this embodiment is a positive terminal protection architecture battery protection chip, which has a positive input terminal VDD, a negative input terminal VSS, a voltage output terminal AOUT, and a detection terminal VM. The chip includes a power switch module, a basic function module, and a battery voltage acquisition and processing unit.

[0065] The first connection terminal of the power switch module is connected to the positive input terminal VDD of the chip, and the second connection terminal is connected to the detection terminal VM of the chip. The power switch module can be one or more PMOS transistors connected in series. When two PMOS transistors are used, the two PMOS transistors are connected in series back to back in a source-to-source configuration.

[0066] The structure of the basic functional module is similar to that of Embodiment 1. Its third and fourth detection terminals are respectively connected to the first and second connection terminals of the power switch module (i.e., the positive input terminal VDD and the detection terminal VM of the chip) for detecting overcurrent and short circuit of the battery. The rest is the same as in Embodiment 1.

[0067] The battery voltage acquisition and processing unit has a positive detection terminal VBAT+, a negative detection terminal VBAT-, and a processing output terminal VOUT. The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit is connected to the positive input terminal VDD of the chip, the negative detection terminal VBAT- is connected to the negative input terminal VSS of the chip, and the processing output terminal VOUT is connected to the voltage output terminal AOUT of the chip.

[0068] The battery voltage acquisition and processing unit uses the potential of the negative input terminal VSS of the chip as a reference to scale the voltage between the positive detection terminal VBAT+ and the negative detection terminal VBAT-, and then outputs a voltage detection signal from its processing output terminal VOUT. The specific circuit structure of the battery voltage acquisition and processing unit is the same as that in Embodiment 1, and will not be described again here.

[0069] Example 6 Please see Figure 9 , Figure 9 This is a structural block diagram of another embodiment of the battery protection system of the present invention. The battery protection system in this embodiment is a positive terminal protection system, including a battery protection chip and a third MCU unit. The battery protection chip used is the battery protection chip of Embodiment 5.

[0070] The positive input terminal VDD of the battery protection chip is electrically connected to the positive terminal of the battery, the negative input terminal VSS is electrically connected to the negative terminal of the battery, the detection terminal VM is electrically connected to the power supply input terminal P+ of the third MCU unit, and the voltage output terminal AOUT is electrically connected to the first input / output terminal I / O1 of the third MCU unit. The ground terminal GND of the third MCU unit is electrically connected to the negative terminal of the battery.

[0071] In this embodiment, since the positive detection terminal VBAT+ of the battery voltage acquisition and processing unit is electrically connected to the positive terminal of the battery through the positive input terminal VDD of the battery protection chip, and the negative detection terminal VBAT- of the battery voltage acquisition and processing unit is electrically connected to the negative terminal of the battery through the negative input terminal VSS of the battery protection chip, the battery voltage acquisition and processing unit will proportionally scale the voltage between the positive and negative terminals of the battery and output a voltage detection signal from the processing output terminal VOUT. For example, when P=1 / 2, the voltage difference between the voltage detection signal and the negative terminal of the battery is half of the battery voltage.

[0072] Since the voltage detection signal in this embodiment is calculated with the negative terminal potential of the battery as a reference, and the ground terminal GND of the third MCU unit is also connected to the negative terminal of the battery, the third MCU unit can also use the negative terminal potential of the battery as a reference to accurately calculate the battery voltage based on the voltage difference between its first input / output terminal I / O1 and the ground terminal GND.

[0073] The working principle of this embodiment is as follows: In overcharge protection trigger scenarios, the basic functional module controls the PMOS transistor in the power switching module to turn off, thus cutting off the main charging circuit. The parasitic diode of the PMOS transistor generates a voltage drop. However, in this embodiment, the battery voltage acquisition and calculation unit scales the voltage between the battery's positive and negative terminals. The ground terminal GND of the third MCU unit is connected to the battery's negative terminal. Using the battery's negative terminal potential as a reference, the third MCU unit calculates the battery voltage based on the voltage difference between its first input / output terminal I / O1 and the ground terminal GND. Since the battery's negative terminal potential is not affected by the PMOS transistor's parasitic diode voltage drop, the voltage calculated by the third MCU unit accurately reflects the battery voltage, achieving precise acquisition and storage of the overcharge voltage.

[0074] This embodiment can also employ a multi-stage battery protection chip series structure. For example, the voltage output terminal AOUT of the first-stage battery protection chip connected to the battery can be electrically connected to the first input / output terminal I / O1 of the third MCU unit, while the voltage output terminals AOUT of the other stages of the battery protection chip are not connected. Since the voltage detection signal output by the first-stage battery protection chip is not affected by the voltage drop of the parasitic diode of the PMOS transistor, the battery voltage can also be accurately acquired. Of course, the first-stage battery protection chip can also be set to only perform overcharge protection. Since this ensures that the first-stage battery protection chip will not activate protection before the second-stage battery protection chip, the voltage output terminal AOUT of the first-stage battery protection chip can also be disconnected, and the voltage output terminal AOUT of the second-stage battery protection chip can be electrically connected to the first input / output terminal I / O1 of the third MCU unit, which can also accurately acquire the battery voltage.

[0075] This embodiment applies to the positive terminal protection architecture, using the battery negative terminal potential as a reference for voltage inversion. After overcharge protection is triggered, even if the parasitic diode of the PMOS transistor generates a voltage drop, the battery negative terminal potential is not affected by this voltage drop, and the voltage inverted by the third MCU unit is the battery voltage. Together with the negative terminal protection scheme, it constitutes a complete positive and negative terminal protection product system.

[0076] Example 7 Please see Figure 10 , Figure 10 This is a structural block diagram of another embodiment of a battery protection chip. The battery protection chip in this embodiment is a positive terminal protection architecture battery protection chip, with a positive input terminal VDD, a negative input terminal VSS, a cascade connection terminal AIN, a voltage output terminal AOUT, and a detection terminal VM. The chip includes a power switch module, a basic function module, and a battery voltage acquisition and processing unit.

[0077] The first connection terminal of the power switch module is connected to the positive input terminal VDD of the chip, and the second connection terminal is connected to the detection terminal VM of the chip. The power switch module can be one or more PMOS transistors connected in series. The structure of the basic functional module is the same as that in Embodiment 1, and will not be described again here.

[0078] The battery voltage acquisition and processing unit has a positive detection terminal VBAT+, a negative detection terminal VBAT-, and a processing output terminal VOUT. The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit is connected to the cascade connection terminal AIN of the chip, the negative detection terminal VBAT- is connected to the negative input terminal VSS of the chip, and the processing output terminal VOUT is connected to the voltage output terminal AOUT of the chip.

[0079] The battery voltage acquisition and processing unit is used to scale the voltage between the positive detection terminal VBAT+ and the negative detection terminal VBAT-, and then outputs a voltage detection signal from the processing output terminal VOUT. Compared with Embodiment 5, this embodiment only adds a cascade connection terminal AIN to the chip, and replaces the positive detection terminal VBAT+ of the battery voltage acquisition and processing unit with the cascade connection terminal AIN connected to the chip. The specific circuit structure of the battery voltage acquisition and processing unit is the same as that of Embodiment 1, and will not be described again here.

[0080] Example 8 Please see Figure 11 , Figure 11 This is a structural block diagram of another embodiment of the battery protection system of the present invention. The battery protection system of this embodiment is a battery positive terminal protection system, including two or more battery protection chips connected in series and a fourth MCU unit. The battery protection chip adopts the battery protection chip of Embodiment 7.

[0081] The negative input terminal VSS of each stage of the battery protection chip and the ground terminal GND of the fourth MCU unit are both electrically connected to the negative terminal of the battery; the positive input terminal VDD and the cascade connection terminal AIN of the first-stage battery protection chip are both electrically connected to the positive terminal of the battery. The positive input terminal VDD of each subsequent stage of the battery protection chip is electrically connected to the detection terminal VM of the previous stage's battery protection chip, and the cascade connection terminal AIN is electrically connected to the voltage output terminal AOUT of the previous stage's battery protection chip. The detection terminal VM of the last stage of the battery protection chip is electrically connected to the power supply input terminal P+ of the fourth MCU unit, and the voltage output terminal AOUT of the last stage of the battery protection chip is electrically connected to the first input / output terminal I / O1 of the fourth MCU unit.

[0082] This embodiment uses a two-stage series-connected battery protection chip as an example. The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit of the first-stage battery protection chip U1 is electrically connected to the positive terminal of the battery through the cascade connection terminal AIN, and the negative detection terminal VBAT- is electrically connected to the negative terminal of the battery through the negative input terminal VSS. Therefore, the first-stage battery voltage acquisition and processing unit scales the voltage between the positive and negative terminals of the battery and outputs a first voltage detection signal from the processing output terminal VOUT to the cascade connection terminal AIN of the second-stage battery protection chip U2.

[0083] The positive detection terminal VBAT+ of the battery voltage acquisition and processing unit of the second-stage battery protection chip U2 is connected to the detection terminal VM of the first-stage battery protection chip U1, while the negative detection terminal VBAT- remains connected to the negative terminal of the battery. The difference between the first voltage detection signal and the battery's negative terminal potential is scaled again to output a second voltage detection signal. This process is repeated stage by stage, with each chip sequentially scaling the voltage signal. Finally, the voltage detection signal received by the fourth MCU unit is the battery voltage value after multiple scaling stages.

[0084] For example, when P=1 / 2, the voltage difference between the first voltage detection signal output by the first-stage battery protection chip U1 and the negative terminal of the battery is half the battery voltage, and the voltage difference between the second voltage detection signal output by the second-stage battery protection chip U2 and the negative terminal of the battery is 1 / 4 of the battery voltage. Of course, since the battery voltage in this embodiment undergoes multiple scaling stages, to avoid the input voltage to the fourth MCU unit being too low, the scaling factor P of the battery voltage acquisition and processing unit can be appropriately increased.

[0085] Since the voltage detection signals at each level are obtained with reference to the negative terminal potential of the battery, and the ground terminal GND of the fourth MCU unit is also connected to the negative terminal of the battery, the fourth MCU unit can accurately calculate the battery voltage based on the voltage difference between its first input / output terminal I / O1 and the ground terminal GND, with reference to the negative terminal potential of the battery.

[0086] The working principle of this embodiment is as follows: In overcharge protection trigger scenarios, the basic functional module controls the PMOS transistor in the power switching module to turn off to cut off the main charging circuit, and the parasitic diode of the PMOS transistor generates a voltage drop. However, in this embodiment, each battery voltage acquisition and calculation unit scales the voltage between the battery negative terminal and the corresponding detection point proportionally. The ground terminal GND of the fourth MCU unit is connected to the battery negative terminal, enabling the fourth MCU unit to perform voltage inverse calculation with the battery negative terminal potential as a reference. Since the battery negative terminal potential is not affected by the voltage drop of the PMOS transistor's parasitic diode, the voltage calculated by the fourth MCU unit can accurately reflect the battery voltage, completing the accurate acquisition and storage of the overcharge voltage.

[0087] In this embodiment, based on embodiments 5 and 6, a multi-level chip series connection is achieved by adding a cascade connection terminal AIN. Each level is scaled proportionally with the battery negative electrode potential as a reference. The circuits at each level are not affected by the voltage drop of the parasitic diode of the PMOS transistor. Thus, the voltage signal can be directly extracted from any level of battery protection chip and the battery voltage can be accurately calculated accordingly. There is no need to limit the detection signal to be taken out from a specific cascade position, which reduces the constraints of system wiring. It can be widely used in series protection scenarios and has strong scalability.

[0088] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A battery protection chip, characterized in that, The chip has a positive input terminal, a negative input terminal, a voltage output terminal, and a detection terminal. The chip includes: The power switching transistor module has its first connection terminal connected to the negative input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the positive input terminal of a chip, its negative detection terminal connected to the negative input terminal of a chip, and its processing output terminal connected to the voltage output terminal of a chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the positive input terminal of the chip as a reference, and then output a voltage detection signal from the detection terminal.

2. A battery protection chip, characterized in that, The chip has a positive input terminal, a negative input terminal, a cascade connection terminal, a voltage output terminal, and a detection terminal. The chip includes: The power switching transistor module has its first connection terminal connected to the negative input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the positive input terminal of a chip, its negative detection terminal connected to the cascade connection terminal of the chip, and its processing output terminal connected to the voltage output terminal of the chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the positive input terminal of the chip as a reference, and then output a voltage detection signal from the voltage output terminal.

3. A battery protection chip, characterized in that, The chip has a positive input terminal, a negative input terminal, a voltage output terminal, and a detection terminal. The chip includes: The power switching transistor module has its first connection terminal connected to the positive input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the positive input terminal of a chip, its negative detection terminal connected to the negative input terminal of a chip, and its processing output terminal connected to the voltage output terminal of a chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the negative input terminal of the chip as a reference, and then output a voltage detection signal from the detection terminal.

4. A battery protection chip, characterized in that, The chip has a positive input terminal, a negative input terminal, a cascade connection terminal, a voltage output terminal, and a detection terminal. The chip includes: The power switching transistor module has its first connection terminal connected to the positive input terminal of the chip, and its second connection terminal connected to the detection terminal of the chip. The basic functional module has a first detection terminal and a second detection terminal connected to the positive input terminal and the negative input terminal of the chip, respectively. The third detection terminal and the fourth detection terminal are connected to the first connection terminal and the second connection terminal of the power switch module, respectively. The drive output terminal is connected to the controlled terminal of the power switch module. The basic functional module is used to detect overcharge and over-discharge of the battery based on the voltage difference between the positive input terminal and the negative input terminal, detect overcurrent and short circuit of the battery based on the voltage difference across the power switch module, and control the power switch module to turn off when an abnormality is detected. A battery voltage acquisition and processing unit has its positive detection terminal connected to the cascade connection terminal of a chip, its negative detection terminal connected to the negative input terminal of the chip, and its processing output terminal connected to the voltage output terminal of the chip. It is used to scale the voltage between the positive and negative detection terminals using the potential of the negative input terminal of the chip as a reference, and then output a voltage detection signal from the voltage output terminal.

5. The battery protection chip according to any one of claims 1 to 4, characterized in that: The battery voltage acquisition and processing unit includes an operational amplifier OP1, resistors R6 and R7; the positive power supply terminal of the operational amplifier OP1 is electrically connected to the positive detection terminal, and the negative power supply terminal of the operational amplifier OP1 is electrically connected to the negative detection terminal; the non-inverting input terminal of the operational amplifier OP1 is electrically connected to the positive detection terminal through resistor R6, and the non-inverting input terminal of the operational amplifier OP1 is also electrically connected to the negative detection terminal through resistor R7; the inverting input terminal of the operational amplifier OP1 is electrically connected to its output terminal, and the output terminal of the operational amplifier OP1 is electrically connected to the voltage output terminal.

6. The battery protection chip as described in claim 5, characterized in that: The scaling factor of the battery voltage acquisition and processing unit is adjusted by adjusting the resistance ratio of resistors R6 and R7.

7. A battery protection system, characterized in that: The device includes a battery protection chip as described in claim 1 and a first MCU unit. The positive input terminal of the battery protection chip is electrically connected to the positive terminal of the battery, and the negative input terminal of the battery protection chip is electrically connected to the negative terminal of the battery. The detection terminal of the battery protection chip is connected to the ground terminal of the first MCU unit, and the voltage output terminal of the battery protection chip is electrically connected to the first input / output terminal of the first MCU unit. The power supply input terminal of the first MCU unit is electrically connected to the positive terminal of the battery. The first MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and its power supply input terminal.

8. A battery protection system, characterized in that: The system includes a battery protection chip as described in claim 2, connected in series in two or more stages, and a second MCU unit. The positive input terminal of each stage of the battery protection chip and the power supply input terminal of the second MCU unit are both electrically connected to the positive terminal of the battery. The negative input terminal and the cascade connection terminal of the first-stage battery protection chip are both electrically connected to the negative terminal of the battery. The negative input terminal of each stage of the battery protection chip after the first stage is electrically connected to the detection terminal of the previous stage battery protection chip, and the cascade connection terminal is electrically connected to the voltage output terminal of the previous stage battery protection chip. The detection terminal of the last stage battery protection chip is electrically connected to the ground terminal of the second MCU unit, and the voltage output terminal is electrically connected to the first input / output terminal of the second MCU unit. The second MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and the power supply input terminal.

9. A battery protection system, characterized in that: The system includes the battery protection chip as described in claim 3 and a third MCU unit. The positive input terminal of the battery protection chip is electrically connected to the positive terminal of the battery, and the negative input terminal of the battery protection chip is electrically connected to the negative terminal of the battery. The detection terminal of the battery protection chip is electrically connected to the power supply input terminal of the third MCU unit, and the voltage output terminal of the battery protection chip is electrically connected to the first input / output terminal of the third MCU unit. The ground terminal of the third MCU unit is electrically connected to the negative terminal of the battery. The third MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and the ground terminal.

10. A battery protection system, characterized in that: The system includes a battery protection chip as described in claim 4, consisting of two or more stages connected in series, and a fourth MCU unit. The negative input terminal of each stage of the battery protection chip and the ground terminal of the fourth MCU unit are both electrically connected to the negative terminal of the battery. The positive input terminal and cascade connection terminal of the first-stage battery protection chip are both electrically connected to the positive terminal of the battery. The positive input terminal of each stage of the battery protection chip after the first stage is electrically connected to the detection terminal of the previous stage battery protection chip, and the cascade connection terminal is electrically connected to the voltage output terminal of the previous stage battery protection chip. The detection terminal of the last stage battery protection chip is electrically connected to the power supply input terminal of the fourth MCU unit, and the voltage output terminal of the last stage battery protection chip is electrically connected to the first input / output terminal of the fourth MCU unit. The fourth MCU unit is used to calculate the battery voltage based on the voltage difference between its first input / output terminal and the ground terminal.

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