Lithium battery equalization protection charging and discharging system

Abstract

The utility model relates to lithium battery charge and discharge technical field, concretely relates to a kind of lithium battery equalization protection charge and discharge system: including charging circuit module, discharge circuit module and equalization protection circuit module, charging circuit module is converted into constant-current constant-voltage power supply with input power supply high efficiency, promote charging efficiency, solve the problem of low charging efficiency;Discharge circuit module converts lithium battery group voltage into multiple stable output and suppresses ripple, meets the power supply demand of external equipment, improves discharge performance, solves the problem of insufficient discharge performance;Equalization protection circuit module monitors the voltage of each cell of lithium battery group in real time, realizes overcurrent protection and voltage equalization, ensures that battery group is safely and stably operated, and makes up equalization protection defect. Through the cooperative work of each module, the system improves the performance and safety of lithium battery charge and discharge system.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery charging and discharging technology, and in particular to a lithium battery equalization protection charging and discharging system. Background Technology

[0002] Currently, with the rapid development of mobile electronic devices, drones, power tools, and other fields, higher requirements are being placed on the efficient charging and discharging and equalization protection of lithium battery packs. Especially in the application of 4S lithium battery packs (i.e., battery packs composed of four individual lithium batteries connected in series), traditional charging and discharging systems generally have the following significant drawbacks:

[0003] Low charging efficiency: Traditional solutions rely on fixed input power (such as a 24V adapter), which is not compatible with fast charging standards such as USB PD protocol, resulting in limited charging power (usually ≤30W).

[0004] Insufficient discharge performance: When there are multiple outputs, traditional systems need to go through multiple boost / buck processes (such as 24V→18V→12V), resulting in accumulated ripple exceeding 100mV, which affects power supply quality;

[0005] Balance protection defects: SOC (State of Charge) estimation relies on the open-circuit voltage method (OCV), which has an error of more than 8% under dynamic operating conditions, resulting in insufficient accuracy of the balance trigger threshold.

[0006] In summary, existing lithium battery charging and discharging systems suffer from problems such as low charging efficiency, insufficient discharge performance, and deficiencies in equalization protection. Summary of the Invention

[0007] The purpose of this invention is to provide a lithium battery equalization protection charging and discharging system to solve the problems of low charging efficiency, insufficient discharge performance and equalization protection defects in existing lithium battery charging and discharging systems.

[0008] To achieve the above objectives, this utility model provides a lithium battery equalization protection charging and discharging system. The lithium battery equalization protection charging and discharging system includes a charging circuit module, a discharging circuit module, and an equalization protection circuit module. The input terminal of the charging circuit module is connected to an external power interface, and the output terminal of the charging circuit module is connected to the charging input terminal of the lithium battery pack. The charging circuit module is used to efficiently convert the input power into a constant current and constant voltage power suitable for charging the lithium battery pack.

[0009] The discharge circuit module is connected to the discharge output terminal of the lithium battery pack, and the output terminal of the discharge circuit module is connected to an external device. The discharge circuit module is used to convert the lithium battery pack voltage into multiple stable outputs and suppress output ripple to meet the power supply requirements of the external device.

[0010] The equalization protection circuit module is electrically connected to the lithium battery pack. The equalization protection circuit module is used to monitor the voltage of each cell in the lithium battery pack in real time, and realize the overcurrent protection and voltage equalization of the lithium battery pack to ensure the safe and stable operation of the battery pack.

[0011] The charging circuit module includes a CH224k protocol chip and a BQ24610 synchronous buck chip. The input terminal of the CH224k protocol chip is connected to an external power interface to receive and adapt the input power of the USB PD protocol. Its output terminal is connected to the input terminal of the BQ24610 synchronous buck chip. The BQ24610 synchronous buck chip is used to convert the adapted input power into a constant current and constant voltage charging power. Its output terminal is connected to the charging input terminal of the lithium battery pack.

[0012] The CH224k protocol chip's connection circuit includes a capacitor C1, resistors R1, R2, and R5. The specific connection circuit of the CH224k protocol chip is as follows:

[0013] The CH224k protocol chip has configuration pins CFG1, CFG2, and CFG3, data pins DP and DM, power pins VDD and VBUS, a power good indicator pin PG, and a ground pin GND. One end of capacitor C1 is connected to the power pin VDD, and the other end of capacitor C1 is grounded. One end of resistor R1 is connected to the configuration pin CFG1, and the other end of resistor R1 is grounded. One end of resistor R2 is connected to the power pin VDD, and the other end of resistor R2 is connected to VBUS. One end of resistor R5 is connected to the power pin VBUS, and the other end of resistor R5 is connected to the USB chip of the external power supply.

[0014] The connection circuit of the BQ24610 synchronous buck chip is specifically as follows:

[0015] The REGN signal is connected to the PH pin of the BQ24610 synchronous buck chip through a circuit consisting of Zener diode D3 and capacitor C47.

[0016] The TS pin of the BQ24610 synchronous buck chip is connected to the reference voltage through resistor R33 via resistor R34, and grounded through resistors R36 and R37. The TS pin of the BQ24610 synchronous buck chip is also grounded through capacitor C57.

[0017] The EP and GND pins of the BQ24610 synchronous buck chip are grounded;

[0018] The TTC pin of the BQ24610 synchronous buck chip is grounded after being connected to capacitor C63.

[0019] The REGN pin of the BQ24610 synchronous buck chip is connected to ground via capacitor C54, and the VREF pin of the BQ24610 synchronous buck chip is connected to ground via capacitor C56.

[0020] The discharge circuit module includes a TPS61178 synchronous boost chip, a first LM25145 synchronous buck chip, and a second LM25145 synchronous buck chip. The input terminal of the TPS61178 synchronous boost chip is connected to the discharge output terminal of the lithium battery pack to boost the battery voltage to 18V. Its output terminal is connected to the input terminal of the first LM25145 synchronous buck chip. The first LM25145 synchronous buck chip is used to buck the boosted voltage to 12V / 5A, and its output terminal serves as the output terminal of the first discharge branch. The input terminal of the second LM25145 synchronous buck chip is directly connected to the discharge output terminal of the lithium battery pack to buck the battery voltage to 5V / 5A, and its output terminal serves as the output terminal of the second discharge branch.

[0021] The connection circuit of the TPS61178 synchronous boost chip is specifically as follows:

[0022] The VIN pin of the TPS61178 synchronous boost chip is connected to the input power supply, which is accessed through switch SW1;

[0023] The VIN pin of the TPS61178 synchronous boost chip is connected to the input power supply through capacitor C13, and the EN pin of the TPS61178 synchronous boost chip is connected to the input power supply through diode D9.

[0024] Capacitors C9, C10, C86, C85, and C84 are connected in parallel between the VIN pin and the input power supply connection circuit of the TPS61178 synchronous boost chip and the VCC pin and the input power supply connection circuit of the TPS61178 synchronous boost chip.

[0025] The SW pin of the TPS61178 synchronous boost chip is connected to the inductor D1 and then to the input power supply.

[0026] The VOUT pin of the TPS61178 synchronous boost chip is connected to a multi-stage filter circuit and then grounded.

[0027] The connection circuits of the first LM25145 synchronous buck chip and the second LM25145 synchronous buck chip are both equipped with multi-stage filtering circuits.

[0028] The equalization protection circuit module includes a BQ40Z50 equalization protection chip, a PMOS transistor, and a chemical fuse. The voltage monitoring terminal of the BQ40Z50 equalization protection chip is connected to the voltage output terminal of each cell in the lithium battery pack for real-time monitoring of the voltage status of each cell. Its control terminal is connected to the gate of the PMOS transistor for controlling the switching on and off of the PMOS transistor based on the monitoring results. The source of the PMOS transistor is connected to the discharge output terminal of the lithium battery pack, and the drain of the PMOS transistor serves as the overcurrent protection output terminal, connected to the subsequent circuit. The chemical fuse is connected in series between the PMOS transistor and the subsequent circuit as a redundant protection element.

[0029] This utility model discloses a lithium battery equalization protection charging and discharging system, comprising a charging circuit module, a discharging circuit module, and an equalization protection circuit module. The charging circuit module efficiently converts the input power into a constant current and constant voltage power supply, improving charging efficiency and solving the problem of low charging efficiency. The discharging circuit module converts the lithium battery pack voltage into multiple stable outputs and suppresses ripple, meeting the power supply requirements of external devices and improving discharging performance, thus solving the problem of insufficient discharging performance. The equalization protection circuit module monitors the voltage of each cell in the lithium battery pack in real time, realizing overcurrent protection and voltage equalization, ensuring the safe and stable operation of the battery pack, and compensating for the deficiencies in equalization protection. Through the coordinated work of each module, the system comprehensively improves the performance and safety of the lithium battery charging and discharging system. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a circuit connection diagram of the CH224k protocol chip provided by this utility model.

[0032] Figure 2 This is a circuit connection diagram of the BQ24610 synchronous buck chip provided by this utility model.

[0033] Figure 3 This is a circuit connection diagram of part A of the TPS61178 synchronous boost chip provided by this utility model.

[0034] Figure 4 This is a circuit connection diagram of part B of the TPS61178 synchronous boost chip provided by this utility model.

[0035] Figure 5This is a circuit connection diagram of part A of the first LM25145 synchronous buck chip provided by this utility model.

[0036] Figure 6 This is a circuit connection diagram of part B of the first LM25145 synchronous buck chip provided by this utility model.

[0037] Figure 7 This is a circuit connection diagram of part A of the second LM25145 synchronous buck chip provided by this utility model.

[0038] Figure 8 This is a circuit connection diagram of part B of the second LM25145 synchronous buck chip provided by this utility model.

[0039] Figure 9 This is a circuit connection diagram of part A of the equalization protection circuit module provided by this utility model.

[0040] Figure 10 This is a circuit connection diagram of part B of the equalization protection circuit module provided by this utility model. Detailed Implementation

[0041] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0042] Please see Figures 1 to 10 This utility model provides a lithium battery equalization protection charging and discharging system, which includes a charging circuit module, a discharging circuit module and an equalization protection circuit module. The input terminal of the charging circuit module is connected to an external power interface, and the output terminal of the charging circuit module is connected to the charging input terminal of the lithium battery pack. The charging circuit module is used to efficiently convert the input power into a constant current and constant voltage power suitable for charging the lithium battery pack.

[0043] The discharge circuit module is connected to the discharge output terminal of the lithium battery pack, and the output terminal of the discharge circuit module is connected to an external device. The discharge circuit module is used to convert the lithium battery pack voltage into multiple stable outputs and suppress output ripple to meet the power supply requirements of the external device.

[0044] The equalization protection circuit module is electrically connected to the lithium battery pack. The equalization protection circuit module is used to monitor the voltage of each cell in the lithium battery pack in real time, and realize the overcurrent protection and voltage equalization of the lithium battery pack to ensure the safe and stable operation of the battery pack.

[0045] In this embodiment, the charging circuit module efficiently converts the input power into a constant current and constant voltage power supply, improving charging efficiency and solving the problem of low charging efficiency. The discharging circuit module converts the lithium battery pack voltage into multiple stable outputs and suppresses ripple, meeting the power supply requirements of external devices, improving discharging performance, and solving the problem of insufficient discharging performance. The equalization protection circuit module monitors the voltage of each cell in the lithium battery pack in real time, realizing overcurrent protection and voltage equalization, ensuring the safe and stable operation of the battery pack, and compensating for the deficiencies in equalization protection. Through the coordinated work of these modules, the system comprehensively improves the performance and safety of the lithium battery charging and discharging system.

[0046] Furthermore, the charging circuit module includes a CH224k protocol chip and a BQ24610 synchronous buck chip. The input terminal of the CH224k protocol chip is connected to an external power interface to receive and adapt the input power of the USB PD protocol. Its output terminal is connected to the input terminal of the BQ24610 synchronous buck chip. The BQ24610 synchronous buck chip is used to convert the adapted input power into a constant current and constant voltage charging power. Its output terminal is connected to the charging input terminal of the lithium battery pack.

[0047] Furthermore, the connection circuit of the CH224k protocol chip is equipped with capacitor C1, resistor R1, resistor R2, and resistor R5. Specifically, the connection circuit of the CH224k protocol chip is as follows:

[0048] The CH224k protocol chip has configuration pins CFG1, CFG2, and CFG3, data pins DP and DM, power pins VDD and VBUS, a power good indicator pin PG, and a ground pin GND. One end of capacitor C1 is connected to the power pin VDD, and the other end of capacitor C1 is grounded. One end of resistor R1 is connected to the configuration pin CFG1, and the other end of resistor R1 is grounded. One end of resistor R2 is connected to the power pin VDD, and the other end of resistor R2 is connected to VBUS. One end of resistor R5 is connected to the power pin VBUS, and the other end of resistor R5 is connected to the USB chip of the external power supply.

[0049] Furthermore, the connection circuit of the BQ24610 synchronous buck chip is specifically as follows:

[0050] The REGN signal is connected to the PH pin of the BQ24610 synchronous buck chip through a circuit consisting of Zener diode D3 and capacitor C47.

[0051] The TS pin of the BQ24610 synchronous buck chip is connected to the reference voltage through resistor R33 via resistor R34, and grounded through resistors R36 and R37. The TS pin of the BQ24610 synchronous buck chip is also grounded through capacitor C57.

[0052] The EP and GND pins of the BQ24610 synchronous buck chip are grounded;

[0053] The TTC pin of the BQ24610 synchronous buck chip is grounded after being connected to capacitor C63.

[0054] The REGN pin of the BQ24610 synchronous buck chip is connected to ground via capacitor C54, and the VREF pin of the BQ24610 synchronous buck chip is connected to ground via capacitor C56.

[0055] Furthermore, the discharge circuit module includes a TPS61178 synchronous boost chip, a first LM25145 synchronous buck chip, and a second LM25145 synchronous buck chip. The input terminal of the TPS61178 synchronous boost chip is connected to the discharge output terminal of the lithium battery pack to boost the battery voltage to 18V. Its output terminal is connected to the input terminal of the first LM25145 synchronous buck chip. The first LM25145 synchronous buck chip is used to buck the boosted voltage to 12V / 5A, and its output terminal serves as the output terminal of the first discharge branch. The input terminal of the second LM25145 synchronous buck chip is directly connected to the discharge output terminal of the lithium battery pack to buck the battery voltage to 5V / 5A, and its output terminal serves as the output terminal of the second discharge branch.

[0056] Furthermore, the connection circuit of the TPS61178 synchronous boost chip is specifically (composed of...). Figure 3 and Figure 4 (Combined composition)

[0057] The VIN pin of the TPS61178 synchronous boost chip is connected to the input power supply, which is accessed through switch SW1;

[0058] The VIN pin of the TPS61178 synchronous boost chip is connected to the input power supply through capacitor C13, and the EN pin of the TPS61178 synchronous boost chip is connected to the input power supply through diode D9.

[0059] Capacitors C9, C10, C86, C85, and C84 are connected in parallel between the VIN pin and the input power supply connection circuit of the TPS61178 synchronous boost chip and the VCC pin and the input power supply connection circuit of the TPS61178 synchronous boost chip.

[0060] The SW pin of the TPS61178 synchronous boost chip is connected to the inductor D1 and then to the input power supply.

[0061] The VOUT pin of the TPS61178 synchronous boost chip is connected to a multi-stage filter circuit and then grounded.

[0062] Furthermore, the connection circuit of the first LM25145 synchronous buck chip (by...) Figure 5 and Figure 6 The connection circuit between the jointly constructed) and the second LM25145 synchronous buck chip (composed of) Figure 7 and Figure 8 Each component (combined with other components) is equipped with a multi-stage filtering circuit.

[0063] Furthermore, the equalization protection circuit module (composed of...) Figure 9 and Figure 10 The battery pack (comprising a BQ40Z50 equalization protection chip, a PMOS transistor, and a chemical fuse) comprises a BQ40Z50 equalization protection chip, a PMOS transistor, and a chemical fuse. The voltage monitoring terminal of the BQ40Z50 equalization protection chip is connected to the voltage output terminal of each cell in the lithium battery pack for real-time monitoring of the voltage status of each cell. Its control terminal is connected to the gate of the PMOS transistor for controlling the switching on and off of the PMOS transistor based on the monitoring results. The source of the PMOS transistor is connected to the discharge output terminal of the lithium battery pack, and the drain of the PMOS transistor serves as the overcurrent protection output terminal, connected to subsequent circuits. The chemical fuse is connected in series between the PMOS transistor and subsequent circuits as a redundant protection element.

[0064] In summary, this solution achieves high-efficiency PD 65W (20V / 3.25A) fast charging through the linkage of the CH224k protocol chip and the BQ24610 synchronous buck chip, with a charging efficiency of 93% and a speed improvement of 40% compared to traditional solutions. The discharge end adopts a TPS61178 boost + LM25145 dual-path multiplexing architecture. The first path boosts the voltage to 18V and then bucks it to 12V / 5A (efficiency 88.3%), while the second path directly bucks it to 5V / 5A (efficiency 90.5%). Combined with multi-stage filtering and dynamic loop optimization, the ripple of both paths is controlled within 50mV, meeting the power supply requirements of high-precision devices. By integrating the equalization protection circuit module, high-precision voltage monitoring (±5mV) and built-in passive equalization function (equalization current 80mA) of the lithium battery pack are achieved, and the equalization trigger threshold (10⁻²) can be programmably set. With a temperature compensation algorithm, the SOC estimation error is ≤5% within the range of -20℃ to 60℃, the overcurrent protection response time is ≤10ms, and the voltage overshoot is suppressed to within ±3%. Through device reuse (LM25145 dual-channel shared) and PCB integration design, the number of components is reduced by 35% and the circuit volume is reduced by 45%. The built-in temperature protection and copper layer heat dissipation scheme ensure that the temperature rise of 5A full load is <35℃, and no external heat dissipation is required. The peak current mode control of LM25145 shortens the dynamic response time to 30μs, and the voltage fluctuation is <3% when the load changes suddenly, which significantly improves the system stability and solves the technical problem of high power, low ripple, equalization protection and miniaturization in multi-string lithium battery systems.

[0065] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Those skilled in the art can understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present utility model are still within the scope of the utility model.

Claims

1. A lithium battery equalization protection charging and discharging system, characterized in that, It includes a charging circuit module, a discharging circuit module, and an equalization protection circuit module. The input terminal of the charging circuit module is connected to an external power interface, and the output terminal of the charging circuit module is connected to the charging input terminal of the lithium battery pack. The charging circuit module is used to efficiently convert the input power into a constant current and constant voltage power supply suitable for charging the lithium battery pack. The discharge circuit module is connected to the discharge output terminal of the lithium battery pack, and the output terminal of the discharge circuit module is connected to an external device. The discharge circuit module is used to convert the lithium battery pack voltage into multiple stable outputs and suppress output ripple to meet the power supply requirements of the external device. The equalization protection circuit module is electrically connected to the lithium battery pack. The equalization protection circuit module is used to monitor the voltage of each cell in the lithium battery pack in real time, and realize the overcurrent protection and voltage equalization of the lithium battery pack to ensure the safe and stable operation of the battery pack. The charging circuit module includes a CH224k protocol chip and a BQ24610 synchronous buck chip. The input terminal of the CH224k protocol chip is connected to an external power interface to receive and adapt the input power of the USB PD protocol. Its output terminal is connected to the input terminal of the BQ24610 synchronous buck chip. The BQ24610 synchronous buck chip is used to convert the adapted input power into a constant current and constant voltage charging power. Its output terminal is connected to the charging input terminal of the lithium battery pack. The CH224k protocol chip's connection circuit includes a capacitor C1, resistors R1, R2, and R5. The specific connection circuit of the CH224k protocol chip is as follows: The CH224k protocol chip has configuration pins CFG1, CFG2, and CFG3, data pins DP and DM, power pins VDD and VBUS, a power good indicator pin PG, and a ground pin GND. One end of capacitor C1 is connected to the power pin VDD, and the other end of capacitor C1 is grounded. One end of resistor R1 is connected to the configuration pin CFG1, and the other end of resistor R1 is grounded. One end of resistor R2 is connected to the power pin VDD, and the other end of resistor R2 is connected to VBUS. One end of resistor R5 is connected to the power pin VBUS, and the other end of resistor R5 is connected to the USB chip of the external power supply.

2. The lithium battery equalization protection charging and discharging system as described in claim 1, characterized in that, The connection circuit of the BQ24610 synchronous buck chip is as follows: The REGN signal is connected to the PH pin of the BQ24610 synchronous buck chip through a circuit consisting of Zener diode D3 and capacitor C47. The TS pin of the BQ24610 synchronous buck chip is connected to the reference voltage through resistor R33 via resistor R34, and grounded through resistors R36 and R37. The TS pin of the BQ24610 synchronous buck chip is also grounded through capacitor C57. The EP and GND pins of the BQ24610 synchronous buck chip are grounded; The TTC pin of the BQ24610 synchronous buck chip is grounded after being connected to capacitor C63. The REGN pin of the BQ24610 synchronous buck chip is connected to ground via capacitor C54, and the VREF pin of the BQ24610 synchronous buck chip is connected to ground via capacitor C56.

3. The lithium battery equalization protection charging and discharging system as described in claim 2, characterized in that, The discharge circuit module includes a TPS61178 synchronous boost chip, a first LM25145 synchronous buck chip, and a second LM25145 synchronous buck chip. The input terminal of the TPS61178 synchronous boost chip is connected to the discharge output terminal of the lithium battery pack to boost the battery voltage to 18V. Its output terminal is connected to the input terminal of the first LM25145 synchronous buck chip. The first LM25145 synchronous buck chip is used to buck the boosted voltage to 12V / 5A, and its output terminal serves as the output terminal of the first discharge branch. The input terminal of the second LM25145 synchronous buck chip is directly connected to the discharge output terminal of the lithium battery pack to buck the battery voltage to 5V / 5A, and its output terminal serves as the output terminal of the second discharge branch.

4. The lithium battery equalization protection charging and discharging system as described in claim 3, characterized in that, The connection circuit of the TPS61178 synchronous boost chip is as follows: The VIN pin of the TPS61178 synchronous boost chip is connected to the input power supply, which is accessed through switch SW1; The VIN pin of the TPS61178 synchronous boost chip is connected to the input power supply through capacitor C13, and the EN pin of the TPS61178 synchronous boost chip is connected to the input power supply through diode D9. Capacitors C9, C10, C86, C85, and C84 are connected in parallel between the VIN pin and the input power supply connection circuit of the TPS61178 synchronous boost chip and the VCC pin and the input power supply connection circuit of the TPS61178 synchronous boost chip. The SW pin of the TPS61178 synchronous boost chip is connected to the inductor D1 and then to the input power supply. The VOUT pin of the TPS61178 synchronous boost chip is connected to a multi-stage filter circuit and then grounded.

5. The lithium battery equalization protection charging and discharging system as described in claim 4, characterized in that, Both the first LM25145 synchronous buck chip and the second LM25145 synchronous buck chip have multi-stage filtering circuits on their connection circuits.

6. The lithium battery equalization protection charging and discharging system as described in claim 5, characterized in that, The equalization protection circuit module includes a BQ40Z50 equalization protection chip, a PMOS transistor, and a chemical fuse. The voltage monitoring terminal of the BQ40Z50 equalization protection chip is connected to the voltage output terminal of each cell in the lithium battery pack for real-time monitoring of the voltage status of each cell. Its control terminal is connected to the gate of the PMOS transistor for controlling the switching on and off of the PMOS transistor based on the monitoring results. The source of the PMOS transistor is connected to the discharge output terminal of the lithium battery pack. The drain of the PMOS transistor serves as the overcurrent protection output terminal and is connected to the subsequent circuit. The chemical fuse is connected in series between the PMOS transistor and the subsequent circuit as a redundant protection element.

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