Marine starting battery charging protection circuit and marine starting battery

Abstract

The utility model provides a marine starting battery charging protection circuit and a marine starting battery. The circuit comprises a battery main control module, a battery voltage acquisition module and a charging protection module, the charging protection module comprises a charging electronic switch tube, a discharging electronic switch tube, an electrical isolation electronic switch tube and a current-limiting protection inductor, the first end of the charging electronic switch tube is connected with the first end of the current-limiting protection inductor, and the second end of the current-limiting protection inductor is connected with the first end of the electrical isolation electronic switch tube; the second end of the electrical isolation electronic switch tube is used for being connected with a charging positive electrode, and the control end of the electrical isolation electronic switch tube is connected with the isolation control end of the battery main control module. When charging overcurrent occurs, the battery voltage collecting module sends collected battery voltage to the battery main control module, the battery main control module controls signals, and at the moment, the current-limiting protection inductor generates forward electromotive force by controlling the duty ratio of the electrical isolation electronic switching tube, so that the charging current is prevented from being too large.

Description

Technical Field

[0001] This disclosure relates to the field of marine battery technology, and in particular to a marine starting battery charging protection circuit and a marine starting battery. Background Technology

[0002] Marine starting batteries are rechargeable batteries specifically designed for ships, primarily used for starting engines and powering onboard equipment. They feature high starting current, high durability, and high deep-cycle capability. They are typically used to start engines, providing starting current for the main engine and auxiliary equipment. In addition, they can be used in emergency power supplies to power critical equipment when the main power source fails. Therefore, marine starting batteries are crucial during ship operation. Because ship engines may need to be started frequently, and ship engines (especially diesel engines) require extremely high starting currents, the battery must provide a large amount of electrical energy in a short time. Therefore, to support this high discharge capacity, the battery needs to be charged with a large current to maintain its performance. However, excessive charging current can also introduce new risks, such as damage to the engine and starter motor, damage to the ship's electrical systems, and damage to the ship's electronic equipment.

[0003] Traditional overcurrent protection relies on fixed threshold fuses or mechanical circuit breakers, which have a slow response time (on the order of seconds) and are unable to cope with instantaneous surge currents. This may lead to misjudgment or delayed action of the protection device, exacerbating battery damage. Utility Model Content

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a marine starting battery charging protection circuit and marine starting battery that effectively improves the charging current limiting protection capability.

[0005] The purpose of this disclosure is achieved through the following technical solution:

[0006] A marine starting battery charging protection circuit includes: a battery main control module, a battery voltage sampling module, and a charging protection module; the sampling terminal of the battery voltage sampling module is used to obtain the charging voltage of each marine starting battery cell, and the battery voltage sampling module is bidirectionally connected to the battery main control module to output a charging protection control signal; the charging protection module includes a charging electronic switch, a discharging electronic switch, an electrical isolation electronic switch, and a current limiting protection inductor; the first terminal of the discharging electronic switch is connected to the first terminal of the charging electronic switch, the second terminal of the discharging electronic switch is grounded, the control terminal of the discharging electronic switch is connected to the first protection terminal of the battery voltage sampling module, the control terminal of the charging electronic switch is connected to the second protection terminal of the battery voltage sampling module, the first terminal of the charging electronic switch is connected to the first terminal of the current limiting protection inductor, the second terminal of the current limiting protection inductor is connected to the first terminal of the electrical isolation electronic switch, the second terminal of the electrical isolation electronic switch is used to connect to the charging positive terminal, and the control terminal of the electrical isolation electronic switch is connected to the isolation control terminal of the battery main control module.

[0007] In one embodiment, the first-level warning duty cycle of the electrically isolated electronic switch is 60% to 80%.

[0008] In one embodiment, the first-level warning duty cycle of the electrically isolated electronic switch is 70%.

[0009] In one embodiment, the charging protection module further includes a pull-up capacitor, the first end of which is connected to the positive charging terminal, the second end of which is connected to the second end of the electrically isolated electronic switch, and the second end of which is also used to connect to the negative charging terminal.

[0010] In one embodiment, the pull-up capacitor is an electrolytic capacitor.

[0011] In one embodiment, the charging protection module further includes an anti-sinking diode, the positive terminal of which is connected to the second terminal of the current limiting protection inductor, and the negative terminal of which is connected to the charging positive terminal.

[0012] In one embodiment, the charging electronic switch, the discharging electronic switch, and the electrical isolation electronic switch are all NMOS transistors.

[0013] In one embodiment, the battery main control module is an STM32G474RET6.

[0014] In one embodiment, the battery pressure sampling module is model BQ7693003DBT.

[0015] A marine starting battery includes the marine starting battery charging protection circuit described in any of the above embodiments.

[0016] Compared with the prior art, this disclosure has at least the following advantages:

[0017] When there is an overcurrent during charging, the battery voltage sampling module sends the sampled battery voltage to the battery main control module. The battery main control module then sends control signals to turn off the charging electronic switch and turn on the discharging electronic switch and the electrical isolation electronic switch. At this time, by controlling the duty cycle of the electrical isolation electronic switch, the current limiting protection inductor generates a positive electromotive force to avoid excessive charging current and effectively improve the charging current limiting protection capability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a circuit diagram of a marine starting battery charging protection circuit in one embodiment;

[0020] Figure 2 This is a circuit system block diagram corresponding to the marine starting battery charging protection circuit in one embodiment. Detailed Implementation

[0021] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] This disclosure relates to a charging protection circuit for marine starting batteries. In one embodiment, the marine starting battery charging protection circuit includes a battery main control module, a battery voltage sampling module, and a charging protection module. The sampling terminal of the battery voltage sampling module is used to sample the charging voltage of each marine starting battery cell. The battery voltage sampling module is bidirectionally connected to the battery main control module to output a charging protection control signal. The charging protection module includes a charging electronic switch, a discharging electronic switch, an electrical isolation electronic switch, and a current limiting protection inductor. The first terminal of the discharging electronic switch is connected to the first terminal of the charging electronic switch, and the second terminal of the discharging electronic switch is grounded. The control terminal of the discharging electronic switch is connected to the first protection terminal of the battery voltage sampling module, and the control terminal of the charging electronic switch is connected to the second protection terminal of the battery voltage sampling module. The first terminal of the charging electronic switch is connected to the first terminal of the current limiting protection inductor, and the second terminal of the current limiting protection inductor is connected to the first terminal of the electrical isolation electronic switch. The second terminal of the electrical isolation electronic switch is used to connect to the charging positive terminal, and the control terminal of the electrical isolation electronic switch is connected to the isolation control terminal of the battery main control module. When there is an overcurrent during charging, the battery voltage sampling module sends the sampled battery voltage to the battery main control module. The battery main control module then sends control signals to turn off the charging electronic switch and turn on the discharging electronic switch and the electrical isolation electronic switch. At this time, by controlling the duty cycle of the electrical isolation electronic switch, the current limiting protection inductor generates a positive electromotive force to avoid excessive charging current and effectively improve the charging current limiting protection capability.

[0025] Please see Figure 1 This is a circuit diagram of a marine starting battery charging protection circuit according to an embodiment of the present disclosure.

[0026] One embodiment of the marine starting battery charging protection circuit 10 includes a battery main control module (MCU), a battery voltage sampling module (AFE), and a charging protection module 100. The sampling terminals of the battery voltage sampling module (AFE) are respectively used to obtain the charging voltage of each individual marine starting battery cell. The battery voltage sampling module (AFE) is bidirectionally connected to the battery main control module (MCU) to enable the battery voltage sampling module (AFE) to output a charging protection control signal. The charging protection module 100 includes a charging electronic switch (C-FET), a discharging electronic switch (D-FET), an electrical isolation electronic switch (LC-FET), and a current-limiting protection inductor (L1). The first terminal of the discharge electronic switch D-FET is connected to the first terminal of the charging electronic switch C-FET. The second terminal of the discharge electronic switch D-FET is grounded. The control terminal of the discharge electronic switch D-FET is connected to the first protection terminal of the battery voltage sampling module AFE. The control terminal of the charging electronic switch C-FET is connected to the second protection terminal of the battery voltage sampling module AFE. The first terminal of the charging electronic switch C-FET is connected to the first terminal of the current limiting protection inductor L1. The second terminal of the current limiting protection inductor L1 is connected to the first terminal of the electrical isolation electronic switch LC-FET. The second terminal of the electrical isolation electronic switch LC-FET is used to connect to the charging positive terminal. The control terminal of the electrical isolation electronic switch LC-FET is connected to the isolation control terminal of the battery main control module MCU.

[0027] In this embodiment, when overcurrent occurs during charging, the battery voltage sampling module (AFE) sends the sampled battery voltage to the battery main control module (MCU). The MCU control signals are detailed in the appendix. Figure 2 The charging electronic switch C-FET is turned off, while the discharging electronic switch D-FET and the electrical isolation electronic switch LC-FET are turned on. At this time, by controlling the duty cycle of the electrical isolation electronic switch LC-FET, the current limiting protection inductor L1 generates a positive electromotive force to avoid excessive charging current and effectively improve the charging current limiting protection capability.

[0028] In one embodiment, the first-stage warning duty cycle of the electrically isolated electronic switch LC-FET is 60% to 80%, specifically, the first-stage warning duty cycle of the electrically isolated electronic switch LC-FET is 70%. In this embodiment, the electrically isolated electronic switch LC-FET acts as a switching device controlling the current passing through the current-limiting protection inductor L1. During charging overcurrent, by adjusting the first-stage warning duty cycle of the electrically isolated electronic switch LC-FET, the magnitude of the current on the current-limiting protection inductor L1 is controlled. This ensures that, during charging, the positive electromotive force generated by the current-limiting protection inductor L1 limits the charging current within a safe range, preventing excessive charging current on each marine starting battery cell and achieving precise charging current-limiting protection for the marine starting battery.

[0029] In another embodiment, when the electrically isolated electronic switch LC-FET is off, the current in the current-limiting protection inductor L1 will not abruptly generate a reverse electromotive force, thus providing a freewheeling circuit to prevent damage from voltage spikes. This approach not only limits the excessive charging current of the marine starting battery but also solves the problem of shortened battery pack life due to excessive current, effectively ensuring charging efficiency.

[0030] In another embodiment, the current-limiting protection inductor L1 is an energy storage inductor, specifically an inductor with an iron-silicon-aluminum magnetic core and an inductance of 22μH±10%.

[0031] In another embodiment, during a first-level charging warning, i.e., when the charging current is greater than 0.9 times the maximum safe charging current and the duration is greater than or equal to 5 seconds, the duty cycle of the electrically isolated electronic switch LC-FET is reduced by 30% to 70% to trigger a CAN bus alarm.

[0032] In another embodiment, when a secondary current limiting warning occurs during charging, i.e. the charging current is greater than the maximum safe charging current and the duration is greater than or equal to 2 seconds, the battery main control module MCU switches the charging mode to constant voltage mode, limits the current to 0.7 times the maximum current, and initiates active balancing.

[0033] In another embodiment, during a Level 3 power failure warning during charging, i.e., when the charging current exceeds 1.2 times the maximum safe charging current, or when the voltage of a single marine starting battery cell exceeds the limit, the battery main control module MCU controls the main relay to cut off and activate the backup slow charging circuit.

[0034] In one embodiment, please refer to Figure 1The charging protection module 100 further includes a pull-up capacitor C1. The first end of the pull-up capacitor C1 is connected to the positive charging terminal, and the second end of the pull-up capacitor C1 is connected to the second end of the electrically isolated electronic switch LC-FET. The second end of the pull-up capacitor is also used to connect to the negative charging terminal. In this embodiment, the pull-up capacitor C1 is connected in series with the second end of the electrically isolated electronic switch LC-FET. Specifically, the pull-up capacitor C1 is located between the second end of the electrically isolated electronic switch LC-FET and the positive charging terminal. When the electrically isolated electronic switch LC-FET is turned on, the pull-up capacitor C1 pulls up the voltage at the second end of the electrically isolated electronic switch LC-FET, increasing the voltage at the second end of the electrically isolated electronic switch LC-FET and providing a stable static operating point for the electrically isolated electronic switch LC-FET.

[0035] In another embodiment, the pull-up capacitor C1 is an electrolytic capacitor, that is, the positive terminal of the pull-up capacitor C1 is connected to the charging positive terminal, and the negative terminal of the pull-up capacitor C1 is connected to the first terminal of the electrically isolated electronic switch transistor LC-FET, so as to provide sufficient pull-up voltage to the first terminal of the electrically isolated electronic switch transistor LC-FET.

[0036] In another embodiment, the pull-up capacitor is a low-ESR solid-state capacitor with a capacitance of 470μF.

[0037] In one embodiment, please refer to Figure 1 The charging protection module 100 further includes an anti-sinking diode D1. The anode of the anti-sinking diode D1 is connected to the second terminal of the current-limiting protection inductor L1, and the cathode of the anti-sinking diode D1 is connected to the charging positive terminal. In this embodiment, the anti-sinking diode D1 is connected in series with the current-limiting protection inductor L1. Specifically, the anti-sinking diode D1 is unidirectionally conductive between the current-limiting protection inductor L1 and the charging positive terminal. The cathode of the anti-sinking diode D1 is connected to the charging positive terminal. During charging overcurrent, it ensures that the current on the charging positive terminal flows only through the electrically isolated electronic switch LC-FET to the current-limiting protection inductor L1. The positive electromotive force generated during charging is limited by the anti-sinking diode D1, avoiding the influence of charging current spike voltage on the current-limiting protection inductor L1 and ensuring the normal current-limiting function of the current-limiting protection inductor L1.

[0038] In another embodiment, the anti-sinking diode is a Schottky diode, model W40G120C51200V / 40A.

[0039] In one embodiment, the charging electronic switch C-FET, the discharging electronic switch D-FET, and the electrically isolated electronic switch LC-FET are all NMOS transistors. The first terminal of the charging electronic switch C-FET, the first terminal of the discharging electronic switch D-FET, and the first terminal of the electrically isolated electronic switch LC-FET are the drains of the NMOS transistors. The second terminal of the charging electronic switch C-FET, the second terminal of the discharging electronic switch D-FET, and the second terminal of the electrically isolated electronic switch LC-FET are the sources of the NMOS transistors. The control terminal of the charging electronic switch C-FET, the control terminal of the discharging electronic switch D-FET, and the control terminal of the electrically isolated electronic switch LC-FET are the gates of the NMOS transistors.

[0040] In another embodiment, the electrically isolated electronic switch LC-FET is an NMOS transistor suitable for a DC-DC topology, which employs a buck converter to control the switching frequency of the electrically isolated electronic switch in order to adjust its PWM.

[0041] In another embodiment, a PWM generator is used to control the duty cycle of the electrically isolated electronic switch LC-FET to suit a DC-DC BUCK circuit.

[0042] In one embodiment, the battery main control module MCU is an STM32G474RET6, a Cortex-M4 with FPU, which supports dual ADC synchronous sampling and is used to calculate parameters such as SOC (State of Charge), SOH (State of Health), and SOP (State of Power) from the data collected by the battery voltage sampling module.

[0043] In another embodiment, the battery main control module (MCU) also samples the charging current through a current sensor. The output of the current sensor is transmitted to the battery main control module via a magnetic coupling isolator with an isolation withstand voltage of 5000Vrms.

[0044] In one embodiment, the battery voltage acquisition module AFE is model BQ7693003DBT, which is used to acquire the health status of marine starting battery cells, such as voltage, current, temperature, SOC and other signals.

[0045] In one embodiment, this disclosure also relates to a marine starting battery, including the marine starting battery charging protection circuit described in any of the above embodiments. In this embodiment, the marine starting battery charging protection circuit includes a battery main control module, a battery voltage sampling module, and a charging protection module. The sampling terminals of the battery voltage sampling module are respectively used to measure the charging voltage of each marine starting battery cell. The battery voltage sampling module is bidirectionally connected to the battery main control module to enable the battery voltage sampling module to output a charging protection control signal. The charging protection module includes a charging electronic switch, a discharging electronic switch, an electrical isolation electronic switch, and a current limiting protection inductor. The first terminal of the discharging electronic switch is connected to the first terminal of the charging electronic switch, and the second terminal of the discharging electronic switch is grounded. The control terminal of the discharging electronic switch is connected to the first protection terminal of the battery voltage sampling module, and the control terminal of the charging electronic switch is connected to the second protection terminal of the battery voltage sampling module. The first terminal of the charging electronic switch is connected to the first terminal of the current limiting protection inductor, and the second terminal of the current limiting protection inductor is connected to the first terminal of the electrical isolation electronic switch. The second terminal of the electrical isolation electronic switch is used to connect to the charging positive terminal, and the control terminal of the electrical isolation electronic switch is connected to the isolation control terminal of the battery main control module. When there is an overcurrent during charging, the battery voltage sampling module sends the sampled battery voltage to the battery main control module. The battery main control module then sends control signals to turn off the charging electronic switch and turn on the discharging electronic switch and the electrical isolation electronic switch. At this time, by controlling the duty cycle of the electrical isolation electronic switch, the current limiting protection inductor generates a positive electromotive force to avoid excessive charging current and effectively improve the charging current limiting protection capability.

[0046] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent disclosure. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent disclosure should be determined by the appended claims.

Claims

1. A marine starting battery charging protection circuit, characterized in that, include: Battery main control module, The battery voltage sampling module has its sampling terminals used to measure the charging voltage of each marine starting battery cell. The battery voltage sampling module is bidirectionally connected to the battery main control module so that the battery voltage sampling module can output a charging protection control signal. A charging protection module includes a charging electronic switch, a discharging electronic switch, an electrical isolation electronic switch, and a current-limiting protection inductor. The first terminal of the discharging electronic switch is connected to the first terminal of the charging electronic switch, and the second terminal of the discharging electronic switch is grounded. The control terminal of the discharging electronic switch is connected to the first protection terminal of the battery voltage sampling module. The control terminal of the charging electronic switch is connected to the second protection terminal of the battery voltage sampling module. The first terminal of the charging electronic switch is connected to the first terminal of the current-limiting protection inductor, and the second terminal of the current-limiting protection inductor is connected to the first terminal of the electrical isolation electronic switch. The second terminal of the electrical isolation electronic switch is used to connect to the charging positive terminal, and the control terminal of the electrical isolation electronic switch is connected to the isolation control terminal of the battery main control module.

2. The marine starting battery charging protection circuit according to claim 1, characterized in that, The first-level warning duty cycle of the electrically isolated electronic switch is 60% to 80%.

3. The marine starting battery charging protection circuit according to claim 2, characterized in that, The first-level warning duty cycle of the electrically isolated electronic switch is 70%.

4. The marine starting battery charging protection circuit according to claim 1, characterized in that, The charging protection module also includes a pull-up capacitor. The first end of the pull-up capacitor is connected to the positive charging terminal, and the second end of the pull-up capacitor is connected to the second end of the electrical isolation electronic switch. The second end of the pull-up capacitor is also used to connect to the negative charging terminal.

5. The marine starting battery charging protection circuit according to claim 4, characterized in that, The pull-up capacitor is an electrolytic capacitor.

6. The marine starting battery charging protection circuit according to claim 1, characterized in that, The charging protection module also includes an anti-sinking diode, the positive terminal of which is connected to the second terminal of the current limiting protection inductor, and the negative terminal of which is connected to the charging positive terminal.

7. The marine starting battery charging protection circuit according to claim 1, characterized in that, The charging electronic switch, the discharging electronic switch, and the electrical isolation electronic switch are all NMOS transistors.

8. The marine starting battery charging protection circuit according to claim 1, characterized in that, The battery main control module is model STM32G474RET6.

9. The marine starting battery charging protection circuit according to claim 1, characterized in that, The battery pressure sampling module is model BQ7693003DBT.

10. A marine starting battery, characterized in that, Includes a marine starting battery charging protection circuit as described in any one of claims 1 to 9.

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