A two-cell voltage difference overlarge detection device and method based on a POS machine

Abstract

The application discloses a two-electric-core voltage difference overlarge detection device based on a POS machine, which comprises a charger, a charging module, a battery, a main control module, a first voltage acquisition module and a second voltage acquisition module, wherein the battery comprises a battery protection module, a first electric core and a second electric core; the charger is connected with the charging module and the first voltage acquisition module respectively; the charging module is connected with the battery protection module and the main control module respectively; the battery protection module is connected with the first electric core, the second electric core and the second voltage acquisition module respectively; the first electric core is connected with the second electric core; and the main control module is connected with the first voltage acquisition module and the second voltage acquisition module respectively. The application further discloses a two-electric-core voltage difference overlarge detection method based on a POS machine, which is used for detecting the voltage difference between the two electric cores of the battery and replacing the abnormal battery in time.

Description

Technical Field

[0001] This invention relates to the field of POS machine technology, and in particular to a device and method for detecting excessive voltage difference between two battery cells in a POS machine. Background Technology

[0002] POS machines typically use a single 7.2V / 7.0V battery, containing two cells connected in series. The cells are primarily made of ternary lithium or lithium iron phosphate. Although the two cells are matched at the factory to ensure their characteristics are nearly identical, differences in their physical properties can develop over time, leading to voltage discrepancies. When the voltage difference between the two cells becomes too large, the battery remains under high voltage, which can negatively impact performance and potentially pose safety hazards.

[0003] Chinese invention patent CN116937723A discloses a battery control circuit, electronic device, and charging control method. The battery control circuit controls the charging and discharging of a battery. The battery control circuit includes a processor and one or more charging links. The battery includes one or more bare cells. Each charging link is electrically connected to both the bare cells and the processor. The processor determines the charging strategy to be executed by the charging link based on the type of the bare cell. This design integrates several bare cells within the same battery, allowing different bare cells to have independent charging and discharging functions, thus maximizing battery performance. However, this solution controls the charging and discharging of the battery through the cells themselves and cannot detect the voltage difference between two cells to avoid potential safety hazards.

[0004] Therefore, there is an urgent need for a device and method for detecting excessive voltage difference between two battery cells based on a POS machine to detect such abnormal batteries. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a detection device for excessive voltage difference between two battery cells based on a POS machine, which is used to detect the voltage difference between the two battery cells and replace abnormal batteries in a timely manner.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by this invention is as follows:

[0007] This invention provides a device for detecting excessive voltage difference between two battery cells based on a POS machine, comprising: a charger, a charging module, a battery, a main control module, a first voltage acquisition module, and a second voltage acquisition module. The battery includes a battery protection module, a first battery cell, and a second battery cell. The charger is connected to the charging module and the first voltage acquisition module, respectively. The charging module is connected to the battery protection module and the main control module, respectively. The battery protection module is connected to the first battery cell, the second battery cell, and the second voltage acquisition module, respectively. The first battery cell and the second battery cell are connected together. The main control module is connected to both the first voltage acquisition module and the second voltage acquisition module.

[0008] Furthermore, the battery protection module includes a chip U1, a control switch circuit, resistors R1 and R2, capacitors C1 and C2, and the chip U1 is model S-8252A; the battery protection module has a power supply positive terminal P+, a power supply negative terminal P-, a battery positive terminal B+, and a battery negative terminal B-, the battery negative terminal B- is a ground terminal, the power supply negative terminal P- serves as a reference potential point, and the battery positive terminal B+ is connected to the power supply positive terminal P+; the power supply positive terminal P+ and the power supply negative terminal P- are respectively connected to the corresponding pins of the charging module, and the power supply positive terminal P+ and the power supply negative terminal P- are also connected to the second voltage acquisition module;

[0009] Pins 1 and 2 of chip U1 are connected to the control switch circuit. Pin 3 of chip U1 is connected to the negative terminal P- of the power supply. Pin 4 of chip U1 is connected to one end of resistor R2 and one end of capacitor C2. Pin 5 of chip U1 is connected to one end of resistor R1 and one end of capacitor C1. Pin 6 of chip U1, the other end of capacitor C1, the other end of capacitor C2, and one end of the control switch circuit are all connected to the negative terminal B- of the battery. The other end of resistor R2 is connected between the first and second battery cells, and the other end of resistor R1 is connected to the positive terminal P+ of the power supply.

[0010] Furthermore, the control switch circuit includes a MOSFET Q1, resistors R6 and R7. The MOSFET Q1 is an AD20K55D3. Pins 1, 2, and 3 of the MOSFET Q1 are all connected to the negative terminal P- of the power supply. Pin 4 of the MOSFET Q1 is connected to one end of resistor R7, and the other end of resistor R7 is connected to pin 2 of chip U1. Pin 5 of the MOSFET Q1 is connected to one end of resistor R6, and the other end of resistor R6 is connected to pin 1 of chip U1. Pins 6, 7, and 8 of the MOSFET Q1 are all connected to the negative terminal B- of the battery.

[0011] Furthermore, the battery protection module also includes a first filter circuit, a second filter circuit, and a third filter circuit. The first filter circuit includes a capacitor C3 and a capacitor C4. One end of the capacitor C3 is connected to the negative terminal B- of the battery, and the other end of the capacitor C3 is connected to one end of the capacitor C4. The other end of the capacitor C4 is connected to the negative terminal P- of the power supply.

[0012] The second filter circuit includes a resistor R3 and a capacitor C5. One end of the resistor R3 and one end of the capacitor C5 are both connected to pin 3 of the chip U1, and the other end of the resistor R3 and the other end of the capacitor C5 are both connected to the negative power supply P-.

[0013] The third filter circuit includes capacitor C6 and capacitor C7. One end of capacitor C6 is connected to the positive terminal P+ of the power supply, and the other end of capacitor C6 is connected to one end of capacitor C7. The other end of capacitor C7 is connected to the negative terminal P- of the power supply.

[0014] Furthermore, the battery protection module also includes a thermistor NTC, one end of which is connected to the negative terminal P- of the power supply, and the other end is connected to the charging module.

[0015] Furthermore, the charging module includes a chip U2, an inductor L, and a light-emitting diode D. STAT Resistance R STAT Resistance R UP Resistance R DN Resistance R ILIM Resistance R ICHG Resistance R ACOKB Resistance R NOR Capacitor C BST Capacitor C SVIN Capacitor C TIM Capacitor C BAT and capacitor C BD The BST pin of the chip U2 is connected to capacitor C. BST One end is connected, and the LX pin of the chip U2 is connected to the capacitor C. BST The other end is connected to one end of the inductor L, and the STAT pin of the chip U2 is connected to the resistor R. STAT One end is connected, the resistor R STAT The other end is connected to the light-emitting diode D STAT The negative terminal of the chip U2 is connected to the resistor R. UP one end and resistor R DN One end of the chip is connected, and the ENB and CV pins of the chip U2 are respectively connected to the corresponding pins of the main control module. The ILIM pin of the chip U2 is connected to the resistor R. ILIMOne end of the chip U2, the SGND / PGND pin, is connected to the negative power supply P-, and the ICHG pin of the chip U2 is connected to the resistor R. ICHG At one end, the ACOKB pin of the chip U2 is connected to resistor R. ACOKB At one end, the TIM pin of the chip U2 is connected to capacitor C. TIM At one end, the NTC pin of the chip U2 is connected to resistor R. NOR One end of the thermistor NTC and the other end of the resistor R NOR The other end is connected to the SVIN pin of chip U2, and the BAT pin of chip U2 is connected to the positive power supply P+ and capacitor C respectively. BAT One end is connected, and the BD pins of the chip U2 are respectively connected to capacitor C. BD One end is connected to the corresponding pin of the main control module;

[0016] The other end of the inductor L, the SVIN pin of the chip U2, and the capacitor C SVIN One end, LED D STAT Positive terminal, resistor R UP The other end and resistor R ACOKB The other end of each is connected to the charger;

[0017] The resistor R DN The other end, capacitor C SVIN The other end, resistor R ILIM The other end, resistor R ICHG The other end, capacitor C TIM The other end, capacitor C BAT The other end and capacitor C BD The other end of each is grounded.

[0018] Furthermore, the positive terminal of the first cell is connected to the positive terminal B+ of the battery, the negative terminal of the first cell is connected to the positive terminal of the second cell, and the negative terminal of the second cell is connected to the negative terminal B- of the battery.

[0019] This invention also provides a method for detecting excessive voltage difference between two battery cells based on a POS machine. This method requires the aforementioned device for detecting excessive voltage difference between two battery cells based on a POS machine, and includes the following steps:

[0020] Step 1: Start the main control module. The main control module collects the voltage of the charger and the battery protection module in real time through the first voltage acquisition module and the second voltage acquisition module, respectively.

[0021] Step 2: Determine the charger insertion status based on the voltage value collected by the first voltage acquisition module. If the charger is inserted normally, proceed to step 3.

[0022] Step 3: Determine the battery connection status by acquiring the voltage value through the second voltage acquisition module. If the battery is connected, proceed to step 4.

[0023] Step 4: Charge the first and second battery cells using the charging module. When the voltage of the first and / or second battery cells reaches the full charge voltage V2 / 2, determine whether the voltage collected by the second voltage acquisition module has reached the full charge voltage V2. If yes, the charging module sends a full charge level signal and stops charging. If no, it indicates that the voltages of the first and second battery cells are asymmetrical and do not reach the full charge voltage V2 set by the charging module. The target battery cell that first reaches the full charge voltage V2 / 2 triggers the battery protection module to activate protection, disconnects charging, and the charging module sends a full charge level signal and stops charging.

[0024] Step 5: Monitor the voltage waveform of the battery during the charging and discharging process. Based on the voltage waveform, determine whether the voltage of the battery suddenly rises before it is fully charged. If so, proceed to step 6; otherwise, the battery is charged normally and the first and second cells are fully charged.

[0025] Step 6: Determine whether there is a voltage rise during the battery discharge process based on the voltage waveform. If yes, proceed to step 7; otherwise, the battery is charging normally and the first and second cells are not fully charged.

[0026] Step 7: Record the voltage V3 before the sudden change and the full-charge voltage V2 when fully charged. Calculate the voltage difference between the first and second cells by calculating the difference between V2 and V3, and reset the full-charge voltage of the charging module to V3.

[0027] Furthermore, step 2 specifically includes:

[0028] Step 21: The main control module determines whether the voltage value collected by the first voltage acquisition module is greater than 0. If it is, it determines that the charger has been inserted and the main control module starts charging. If not, the charging module's notification function is enabled and the charging module notifies the main control module. The main control module determines that the charger insertion has been interrupted, re-inserts the charger, generates a response signal, and the main control module starts charging.

[0029] Step 22: The main control module determines whether the voltage value collected by the first voltage acquisition module meets the voltage threshold condition. If yes, proceed to step 3; otherwise, the main control module controls the charging module to shut down and prompts the user.

[0030] Furthermore, step 3 specifically involves: the main control module determining whether the voltage value acquired by the second voltage acquisition module is greater than 0. If it is, it determines that a battery is connected and starts the charging function of the charging module; if not, the main control module controls the charging module to shut down and prompts the user.

[0031] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0032] (1) By cooperating with the battery protection module and the charging module, the charging process of the first and second cells connected in series is monitored in real time, the voltage difference between the first and second cells is identified, the abnormal battery is identified, and the battery is protected by limiting the full charge voltage, so that the battery that has been used for a long time is always in a safe voltage state, which can effectively prevent safety hazards.

[0033] (2) No additional complex hardware circuits are required. Only a normal charging module and battery protection module, plus a first voltage acquisition module and a second voltage acquisition module for real-time voltage detection, are needed to complete the detection. The cost is low and the operation is simple. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a device for detecting excessive voltage difference between two battery cells based on a POS machine, provided in an embodiment of the present invention.

[0036] Figure 2 This is a specific structural circuit diagram of the battery provided in an embodiment of the present invention.

[0037] Figure 3 This is a specific structural circuit diagram of the charging module provided in an embodiment of the present invention.

[0038] Figure 4 This is a voltage change diagram of an abnormal battery during the charging process provided in an embodiment of the present invention.

[0039] Figure 5 This is a voltage change diagram of a normal battery during the charging process provided in an embodiment of the present invention.

[0040] Figure 6 This is an execution flowchart of a method for detecting excessive voltage difference between two battery cells based on a POS machine, provided in an embodiment of the present invention.

[0041] Explanation of the labels in the diagram:

[0042] 1-Charger, 2-Charging module, 3-Battery, 31-Battery protection module, 311-Control switch circuit, 312-First filter circuit, 313-Second filter circuit, 314-Third filter circuit, 32-First battery cell, 33-Second battery cell, 4-Main control module, 5-First voltage acquisition module, 6-Second voltage acquisition module. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Please see Figures 1-3 The present invention discloses a device for detecting excessive voltage difference between two battery cells based on a POS machine, comprising: a charger 1, a charging module 2, a battery 3, a main control module 4, a first voltage acquisition module 5, and a second voltage acquisition module 6. The battery 3 includes a battery protection module 31, a first battery cell 32, and a second battery cell 33. The charger 1 is connected to the charging module 2 and the first voltage acquisition module 5, respectively. The charging module 2 is connected to the battery protection module 31 and the main control module 4, respectively. The battery protection module 31 is connected to the first battery cell 32, the second battery cell 33, and the second voltage acquisition module 6, respectively. The first battery cell 32 is connected to the second battery cell 33. The main control module 4 is connected to the first voltage acquisition module 5 and the second voltage acquisition module 6, respectively.

[0045] The charger 1 is a device that connects to the charging interface to achieve charging; the charging module 2 boosts the input voltage to the voltage required by the battery 3, thus charging the battery 3; when the battery 3 is connected to the charger, it is charged through the charging module, and when the charger is disconnected, it discharges to external devices; the main control module 4 is used to control the charging module 2, the first voltage acquisition module 5, and the second voltage acquisition module 6 to realize the opening and closing of charging; the first voltage acquisition module 5 is used to acquire the voltage at both ends of the charger 1; the second voltage acquisition module 6 is used to acquire the voltage at both ends of the battery protection module 31 (i.e., the battery 3).

[0046] In this embodiment, the battery protection module 31 includes a chip U1, a control switch circuit 311, resistors R1 and R2, capacitors C1 and C2, and the chip U1 is model S-8252A; the battery protection module 31 has a power supply positive terminal P+, a power supply negative terminal P-, a battery positive terminal B+, and a battery negative terminal B-, the battery negative terminal B- is a ground terminal, the power supply negative terminal P- is a reference potential point, and the battery positive terminal B+ is connected to the power supply positive terminal P+; the power supply positive terminal P+ and the power supply negative terminal P- are respectively connected to the corresponding pins of the charging module 2, and the power supply positive terminal P+ and the power supply negative terminal P- are also connected to the second voltage acquisition module 6;

[0047] Pins 1 and 2 of chip U1 are connected to control switch circuit 311. Pin 3 of chip U1 is connected to the negative terminal P- of the power supply. Pin 4 of chip U1 is connected to one end of resistor R2 and one end of capacitor C2. Pin 5 of chip U1 is connected to one end of resistor R1 and one end of capacitor C1. Pin 6 of chip U1, the other end of capacitor C1, the other end of capacitor C2, and one end of control switch circuit 311 are all connected to the negative terminal B- of the battery. The other end of resistor R2 is connected between the first battery cell 32 and the second battery cell 33. The other end of resistor R1 is connected to the positive terminal P+ of the power supply. The voltage VCELL1 across the first electrical chip CELL1 can be obtained through pins 4 and 5 of chip U1, and the voltage VCELL2 across the second electrical chip CELL2 can be obtained through pins 4 and 6 of chip U1. Once VCELL1 and / or VCELL2 reach the full charge voltage V2 / 2, pins 1 and 2 of chip U1 will send a signal to the control switch circuit 311. After receiving the signal, the control switch circuit 311 controls the MOSFET Q1 to turn off, thus stopping the charging process.

[0048] In this embodiment, the control switch circuit 311 includes a MOSFET Q1, resistors R6 and R7. The MOSFET Q1 is an AD20K55D3. Pins 1, 2, and 3 of the MOSFET Q1 are all connected to the negative terminal P- of the power supply. Pin 4 of the MOSFET Q1 is connected to one end of resistor R7, and the other end of resistor R7 is connected to pin 2 of chip U1. Pin 5 of the MOSFET Q1 is connected to one end of resistor R6, and the other end of resistor R6 is connected to pin 1 of chip U1. Pins 6, 7, and 8 of the MOSFET Q1 are all connected to the negative terminal B- of the battery. The battery protection module 31 is turned on or off by turning the MOSFET Q1 on or off, thereby turning the charging module 2 on or off.

[0049] In this embodiment, the battery protection module 31 further includes a first filter circuit 312, a second filter circuit 313 and a third filter circuit 314. The first filter circuit 312 includes a capacitor C3 and a capacitor C4. One end of the capacitor C3 is connected to the negative terminal B- of the battery, and the other end of the capacitor C3 is connected to one end of the capacitor C4. The other end of the capacitor C4 is connected to the negative terminal P- of the power supply.

[0050] The second filter circuit 313 includes a resistor R3 and a capacitor C5. One end of the resistor R3 and one end of the capacitor C5 are both connected to the third pin of the chip U1, and the other end of the resistor R3 and the other end of the capacitor C5 are both connected to the negative power supply P-.

[0051] The third filter circuit 314 includes capacitors C6 and C7. One end of capacitor C6 is connected to the positive terminal P+ of the power supply, and the other end of capacitor C6 is connected to one end of capacitor C7. The other end of capacitor C7 is connected to the negative terminal P- of the power supply. The signal is filtered by the first filter circuit 312, the second filter circuit 313, and the third filter circuit 314 to improve the availability and reliability of the signal.

[0052] In this embodiment, the battery protection module 31 further includes a thermistor NTC. One end of the thermistor NTC is connected to the negative terminal P- of the power supply, and the other end is connected to the charging module 2. The thermistor NTC can monitor the temperature of the charging module 2 during the charging process, thereby ensuring the safety of the charging process.

[0053] In this embodiment, the charging module 2 includes a chip U2, an inductor L, and a light-emitting diode D. STAT Resistance R STAT Resistance R UP Resistance R DN Resistance R ILIM Resistance R ICHG Resistance R ACOKB Resistance R NOR Capacitor C BST Capacitor C SVIN Capacitor C TIM Capacitor C BAT and capacitor C BD The BST pin of the chip U2 is connected to capacitor C. BST One end is connected, and the LX pin of the chip U2 is connected to the capacitor C. BST The other end is connected to one end of the inductor L, and the STAT pin of the chip U2 is connected to the resistor R. STAT One end is connected, the resistor R STAT The other end is connected to the light-emitting diode D STAT The negative terminal of the chip U2 is connected to the resistor R.UP one end and resistor R DN One end of the chip is connected, and the ENB and CV pins of the chip U2 are respectively connected to the corresponding pins of the main control module 4. The ILIM pin of the chip U2 is connected to the resistor R. ILIM One end of the chip U2, the SGND / PGND pin, is connected to the negative power supply P-, and the ICHG pin of the chip U2 is connected to the resistor R. ICHG At one end, the ACOKB pin of the chip U2 is connected to resistor R. ACOKB At one end, the TIM pin of the chip U2 is connected to capacitor C. TIM At one end, the NTC pin of the chip U2 is connected to resistor R. NOR One end of the thermistor NTC and the other end of the resistor R NOR The other end is connected to the SVIN pin of chip U2, and the BAT pin of chip U2 is connected to the positive power supply P+ and capacitor C respectively. BAT One end is connected, and the BD pins of the chip U2 are respectively connected to capacitor C. BD One end is connected to the corresponding pin of the main control module 4;

[0054] The other end of the inductor L, the SVIN pin of the chip U2, and the capacitor C SVIN One end, LED D STAT Positive terminal, resistor R UP The other end and resistor R ACOKB The other end of each is connected to charger 1;

[0055] The resistor R DN The other end, capacitor C SVIN The other end, resistor R ILIM The other end, resistor R ICHG The other end, capacitor C TIM The other end, capacitor C BAT The other end and capacitor C BD The other end is grounded. The voltage input to charger 1 can be boosted to the voltage required by battery 3 by chip U2, thus charging battery 3.

[0056] In this embodiment, the positive terminal of the first cell 32 is connected to the positive terminal B+ of the battery, the negative terminal of the first cell 32 is connected to the positive terminal of the second cell 33, and the negative terminal of the second cell 33 is connected to the negative terminal B- of the battery.

[0057] The working principle of this invention is as follows:

[0058] During charging, the chip U2 of the charging module 2 boosts the input voltage (the input voltage of the charger 1 is 5V) to the voltage required for charging the battery 3, and charges the battery 3. The BAT pin of the chip U2 is connected to the positive power supply P+ pin of the battery 3, and the SGND / PGND pin of the chip U2 is connected to the negative power supply P-.

[0059] During normal charging, battery 3 charges from depleted voltage V1 to full voltage V2, transitioning from constant current charging to constant voltage charging until battery 3 is fully charged. The entire process is controlled by charging module 2, and battery protection module 31 does not activate under normal charging conditions.

[0060] When a voltage difference occurs in battery 3, that is, when the voltages of the first cell 32 and the second cell 33 (VCELL1 and VCELL2 respectively) are different, i.e.:

[0061] VCELL1-VCELL2≠0

[0062] The difference between the first cell 32 and the second cell 33 is set to: △V

[0063] Therefore, |VCELL1-VCELL2|=△V.

[0064] During the charging process, it is assumed that the second cell 33 in battery 3 will be charged to the full voltage V2 / 2 by the charging module 2 (VCELL2>VCELL1); VCELL1+△V=VCELL2;

[0065] At this time, the full voltage V2 = VCELL1 + VCELL2 = (VCELL1 + ΔV) + VCELL2;

[0066] In the battery protection module 31, the voltage difference between the first cell 32 (VCELL1) and the second cell 33 (VCELL2) is no longer the same. The first cell 32 (VCELL1) and the second cell 33 (VCELL2) are connected to the two ends of chip U1 in the battery protection module 31. The battery protection module 31 can detect the voltages of the first cell 32 and the second cell 33 through chip U1. When one of the cells reaches the full charge voltage V2 / 2, the battery protection module 31 will close the charging circuit and turn off MOSFET Q1. Because the charging circuit of battery 3 is closed, the voltage of chip U2 in the charging module 2 will quickly rise to the full charge voltage V2, triggering the full charge condition of the charging module 2 and stopping charging. The entire system charging is complete.

[0067] At this time, only one of the two cells in battery 3 is fully charged, while the other is not fully charged. The voltage difference between this cell and the fully charged voltage is ΔV.

[0068] The total voltage of the two cells in battery 3 is: V3 = V2 - ΔV

[0069] Because the charging circuit is closed, the actual discharge from the cell is not V3, but V3-VD. After the charging circuit of battery 3 is closed, the series voltage V3 of the two cells discharges through MOSFET Q1. Since the charging circuit is closed, the cell needs to discharge through the body diode of MOSFET Q1 during discharge, which will cause a voltage drop in VD.

[0070] Brief description of the charging process of differential voltage battery 3: Battery 3 slowly charges from a low charge level (V1) to V3, triggering the battery protection module 31, causing the charging voltage to rise instantaneously to V2. The charging module 2 then shuts off charging after detecting the full charge condition. Since the battery protection module 31 is still active, battery 3 outputs a voltage of V3-VD. After a period of time, due to the power consumption of battery 3, the cell voltage that triggered the protection decreases, reaching the threshold of the protection tripping. The voltage slowly drops to V3-VD-VP, and the battery protection module 31 shuts off the protection. At this time, the discharge circuit of battery 3 switches from the body diode of MOSFET Q1 back to the conducting MOSFET Q1. The output voltage will experience a rise in VD, rising to V3-VP. The voltage change during the charging process of an abnormal battery is as follows: Figure 4 As shown, the voltage change during the charging process of a normal battery is as follows: Figure 5 As shown.

[0071] V1: Low battery voltage;

[0072] V2: Full battery voltage;

[0073] V3: Voltage of the abnormal differential voltage battery after it is fully charged;

[0074] VP: Voltage drop before the battery protection chip is deactivated;

[0075] VD: Voltage drop across the MOSFET body diode;

[0076] VCELL: Cell voltage;

[0077] △V: Voltage difference between two battery cells;

[0078] The POS device detects the voltage of battery 3 in real time during the charging process, identifies abnormal battery 3, and calculates the voltage difference ΔV. In the second charge, the full charge voltage of the POS device is set to be lower than V2-ΔV, which ensures that none of the cells will be charged to the point where the battery protection module 31 is activated, thus effectively ensuring that all batteries 3 are within a reasonable charging voltage range.

[0079] By reducing the full-charge voltage, although the full capacity of battery 3 cannot be fully utilized, battery 3 is protected, ensuring that even after prolonged use, battery 3 remains at a safe voltage, effectively preventing potential safety hazards.

[0080] like Figure 6As shown, the present invention also provides a method for detecting excessive voltage difference between two battery cells based on a POS machine. This method requires the aforementioned device for detecting excessive voltage difference between two battery cells based on a POS machine, and includes the following steps:

[0081] Step 1: Start the main control module 4. The main control module 4 collects the voltage of the charger 1 and the battery protection module 31 in real time through the first voltage acquisition module 5 and the second voltage acquisition module 6, respectively.

[0082] Step 2: Determine the insertion status of charger 1 by the voltage value collected by the first voltage acquisition module 5. If charger 1 is inserted normally, proceed to step 3.

[0083] In this embodiment, step 2 specifically includes:

[0084] Step 21: The main control module 4 determines whether the voltage value collected by the first voltage acquisition module 5 is greater than 0. If it is, it determines that the charger 1 has been inserted and the main control module 4 starts charging. If not, the notification function of the charging module 2 is enabled and the main control module 4 is notified through the charging module 2. The main control module 4 determines that the insertion of the charger 1 has been interrupted, and the charger 1 is reinserted. The charging module 2 generates a response signal and the main control module 4 starts charging.

[0085] Step 22: The main control module 4 determines whether the voltage value collected by the first voltage acquisition module 5 meets the voltage threshold condition. If yes, proceed to step 3; otherwise, the main control module 4 controls the charging module 2 to shut down and prompts the user.

[0086] Step 3: Determine the battery 3 connection status by collecting the voltage value through the second voltage acquisition module 6. If the battery 3 is connected, proceed to step 4.

[0087] In this embodiment, step 3 specifically involves: the main control module 4 determining whether the voltage value collected by the second voltage acquisition module 6 is greater than 0. If it is, it is determined that a battery 3 is connected, and the charging function of the charging module 2 is turned on; if not, the main control module 4 controls the charging module 2 to turn off and prompts the user.

[0088] Step 4: Charge the first cell 32 and the second cell 33 through the charging module 2. When the voltage of the first cell 32 and / or the second cell 33 reaches the full charge voltage V2 / 2, determine whether the voltage collected by the second voltage acquisition module 6 has reached the full charge voltage V2. If yes, the charging module 2 sends a full charge level signal and stops charging. If no, it means that the voltages of the first cell 32 and the second cell 33 are asymmetrical and do not reach the full charge voltage V2 set by the charging module 2. The target cell that first reaches the full charge voltage V2 / 2 triggers the battery protection module 31 to activate the protection action, disconnects charging, and the charging module 2 sends a full charge level signal and stops charging.

[0089] Step 5: Monitor the voltage waveform of battery 3 during the charging and discharging processes. Based on the voltage waveform, determine whether the voltage of battery 3 suddenly rises before it is fully charged. If so, proceed to step 6; otherwise, battery 3 is charged normally and the first cell 32 and the second cell 33 are fully charged.

[0090] Step 6: Determine whether there is a voltage rise during the discharge process of battery 3 based on the voltage waveform. If yes, proceed to step 7; otherwise, battery 3 is charging normally and the first cell 32 and the second cell 33 are not fully charged.

[0091] Step 7: Record the voltage V3 before the sudden change and the full-charge voltage V2 when fully charged. Calculate the voltage difference between the first cell 32 and the second cell 33 by calculating the difference between V2 and V3, and reset the full-charge voltage of the charging module 2 to V3.

[0092] The above description is only a part of the embodiments of the present invention and does not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made based on the content of the present invention specification and drawings, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A POS-based two-cell voltage difference overlarge detection method, characterized in that, The method needs to provide two cell voltage difference detection devices, including: a charger, a charging module, a battery, a main control module, a first voltage acquisition module and a second voltage acquisition module, the battery includes a battery protection module, a first cell and a second cell, the charger is connected with the charging module and the first voltage acquisition module respectively, the charging module is connected with the battery protection module and the main control module respectively, the battery protection module is connected with the first cell, the second cell and the second voltage acquisition module respectively, the first cell is connected with the second cell, the main control module is connected with the first voltage acquisition module and the second voltage acquisition module respectively; The specific steps are as follows: Step 1, start the main control module, the main control module acquires the voltage of the charger and the battery protection module in real time through the first voltage acquisition module and the second voltage acquisition module; Step 2, judge the charger insertion state through the voltage value collected by the first voltage acquisition module, when the charger is inserted normally, enter step 3; Step 3, judge the battery access state through the voltage value collected by the second voltage acquisition module, when the battery is accessed, enter step 4; Step 4, charge the first cell and the second cell through the charging module, when the voltage of the first cell and / or the second cell reaches the full voltage V2 / 2, judge whether the voltage collected by the second voltage acquisition module reaches the full voltage V2, if yes, the charging module sends a full charging level signal and closes the charging; if not, it means that the voltage of the first cell and the second cell is not symmetrical and cannot reach the full voltage V2 set by the charging module, the target cell reaching the full voltage V2 / 2 triggers the battery protection module to start the protection action and disconnect the charging, and the charging module sends a full charging level signal and closes the charging; Step 5, monitor the voltage waveform of the battery in the charging process and the discharging process, and judge whether the voltage suddenly rises before the battery is fully charged according to the voltage waveform, if yes, enter step 6; if not, the battery is normally charged and the first cell and the second cell are fully charged; Step 6, judge whether the voltage rises during the discharging process of the battery according to the voltage waveform, if yes, enter step 7; if not, the battery is normally charged and the first cell and the second cell are not fully charged; Step 7, record the voltage V3 before the mutation and the full voltage V2 when fully charged, calculate the difference between V2 and V3 to get the voltage difference between the first cell and the second cell, and reset the full voltage of the charging module to V3.

2. The method for detecting overdischarge of two battery cells based on POS machine according to claim 1, wherein, The battery protection module includes a chip U1, a control switch circuit, resistors R1 and R2, capacitors C1 and C2, the model of the chip U1 is S-8252A; the battery protection module has a power positive pole P+, a power negative pole P-, a battery positive pole B+ and a battery negative pole B-, the battery negative pole B- is a ground terminal, the power negative pole P- is a reference potential point, the battery positive pole B+ is connected with the power positive pole P+; the power positive pole P+ and the power negative pole P- are connected to the corresponding pins of the charging module respectively, and the power positive pole P+ and the power negative pole P- are also connected to the second voltage acquisition module; The first pin and the second pin of the chip U1 are connected to a control switch circuit, the third pin of the chip U1 is connected to a power supply negative pole P-, the fourth pin of the chip U1 is connected to one end of a resistor R2 and one end of a capacitor C2 respectively, the fifth pin of the chip U1 is connected to one end of a resistor R1 and one end of a capacitor C1 respectively, and the sixth pin of the chip U1, the other end of the capacitor C1, the other end of the capacitor C2 and one end of the control switch circuit are all connected to a battery negative pole B-; the other end of the resistor R2 is connected between the first battery cell and the second battery cell, and the other end of the resistor R1 is connected to a power supply positive pole P+.

3. The method of claim 2, wherein the method comprises: The control switch circuit comprises a MOS tube Q1, a resistor R6 and a resistor R7, the MOS tube Q1 is AD20K55D3, the first pin, the second pin and the third pin of the MOS tube Q1 are all connected to the power supply negative pole P-, the fourth pin of the MOS tube Q1 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to the second pin of the chip U1, the fifth pin of the MOS tube Q1 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the first pin of the chip U1, and the sixth pin, the seventh pin and the eighth pin of the MOS tube Q1 are all connected to the battery negative pole B-.

4. The method of claim 2, wherein the method comprises: The battery protection module further comprises a first filter circuit, a second filter circuit and a third filter circuit, the first filter circuit comprises a capacitor C3 and a capacitor C4, one end of the capacitor C3 is connected to the battery negative pole B-, the other end of the capacitor C3 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is connected to the power supply negative pole P-; The second filter circuit comprises a resistor R3 and a capacitor C5, one end of the resistor R3 and one end of the capacitor C5 are both connected to the third pin of the chip U1, and the other end of the resistor R3 and the other end of the capacitor C5 are both connected to the power supply negative pole P-; The third filter circuit comprises a capacitor C6 and a capacitor C7, one end of the capacitor C6 is connected to the power supply positive pole P+, the other end of the capacitor C6 is connected to one end of the capacitor C7, and the other end of the capacitor C7 is connected to the power supply negative pole P-.

5. The method of claim 2, wherein the method comprises: The battery protection module further comprises a thermistor NTC, one end of the thermistor NTC is connected to the power supply negative pole P-, and the other end of the thermistor NTC is connected to the charging module.

6. The method of claim 5, wherein the method comprises: The charging module includes a chip U2, an inductor L, a light emitting diode D STAT , a resistor R STAT , a resistor R UP , a resistor R DN , a resistor R ILIM , a resistor R ICHG , a resistor R ACOKB , a resistor R NOR , a capacitor C BST , a capacitor C SVIN , a capacitor C TIM , a capacitor C BAT , and a capacitor C BD One end of the capacitor C BST is connected to the BST pin of the chip U2, the other end of the capacitor C BST and one end of the inductor L are respectively connected to the LX pin of the chip U2, one end of the resistor R STAT is connected to the STAT pin of the chip U2, the other end of the resistor R STAT is connected to the negative electrode of the light emitting diode D STAT , one end of the resistor R UP and one end of the resistor R DN are respectively connected to the VSEN pin of the chip U2, the ENB pin and the CV pin of the chip U2 are respectively connected to the corresponding pins of the main control module, one end of the resistor R ILIM is connected to the ILIM pin of the chip U2, the SGND / PGND pin of the chip U2 is connected to the negative electrode P- of the power supply, one end of the resistor R ICHG is connected to the ICHG pin of the chip U2, one end of the resistor R ACOKB is connected to the ACOKB pin of the chip U2, one end of the capacitor C TIM is connected to the TIM pin of the chip U2, one end of the resistor R NOR and the other end of the thermistor NTC are respectively connected to the NTC pin of the chip U2, the other end of the resistor R NOR is connected to the SVIN pin of the chip U2, one end of the capacitor C BAT is respectively connected to the BAT pin and the positive electrode P+ of the power supply, one end of the capacitor C BD is respectively connected to the BD pin of the chip U2 and the corresponding pin of the main control module. The other end of the inductor L, the SVIN pin of the chip U2, one end of the capacitor C SVIN , the anode of the light emitting diode D STAT , the other end of the resistor R UP , and the other end of the resistor R ACOKB are all connected to the charger; The other end of the resistor R DN The other end of the capacitor C SVIN The other end of the resistor R ILIM The other end of the resistor R ICHG The other end of the capacitor C TIM The other end of the capacitor C BAT The other end of the capacitor C BD are grounded.

7. The method of claim 2, wherein the method comprises: determining whether the voltage difference between the two battery cells is greater than a predetermined threshold value; and if the voltage difference is greater than the predetermined threshold value, outputting a signal to the POS machine to stop the POS machine from operating. The positive pole of the first battery cell is connected to a battery positive pole B+, the negative pole of the first battery cell is connected to the positive pole of the second battery cell, and the negative pole of the second battery cell is connected to the battery negative pole B-.

8. The method for detecting excessive voltage difference between two battery cells based on a POS machine as described in claim 1, characterized in that, The step 2 specifically comprises: Step 21, judging whether the voltage value collected by the first voltage collection module is greater than 0 through the main control module, if yes, judging that the charger is inserted and starting charging, if not, starting the notification function of the charging module, notifying the main control module through the charging module, judging that the charger is inserted interruption by the main control module, reinserting the charger, generating a response signal by the charging module, and starting charging. Step 22, judging whether the voltage value collected by the first voltage collecting module meets the voltage threshold condition through the master control module, if yes, entering step 3; if no, the master control module controls the charging module to be closed, and prompts the user.

9. The method for detecting excessive voltage difference between two battery cells based on a POS machine as described in claim 1, characterized in that, The step 3 is specifically: judging whether the voltage value collected by the second voltage collecting module is greater than 0 through the master control module, if yes, judging that there is a battery connected, and the charging function of the charging module is started; if no, the master control module controls the charging module to be closed, and prompts the user.

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