CN214380221U - Battery charging and discharging protection device - Google Patents

Abstract

The utility model discloses a battery charge-discharge protection device to solve the technical problem that current battery management can't guarantee battery life, compatibility are not enough. The utility model discloses a battery management module, control module, switch module, the partial pressure module, switch module and partial pressure module are parallelly connected to form first node and second node, first node is connected with the battery of protection, the second node connection discharge port/port of charging, battery management module's input and battery are connected, its output and control module's input correspond the connection, switch module includes the on-off control end of corresponding the connection with control module, switch module switches on and can make the partial pressure module by the short circuit. The beneficial effects of the utility model reside in that: compatibility is strong, promotes the life of battery, better preventing overcharge and overdischarge.

Description

Battery charging and discharging protection device

Technical Field

The utility model relates to a power protection technical field, concretely relates to battery charge-discharge protection device.

Background

The lithium ion battery has the advantages of high energy density, high battery voltage, less self-discharge, long cycle life, environmental protection and the like, is widely applied to various electronic products, but has short service life (cycle times) and great waste compared with the lithium iron phosphate battery, so that the lithium ion battery has important significance in prolonging the service life.

The 'charging method for prolonging the service life of the lithium battery' is recorded in the '2009, 2 nd volume of technical information', the cycle life of the lithium battery can be prolonged by reducing the charging voltage and selecting a proper charging termination current, and the 'influence of the discharging depth on the service life of the battery' is disclosed in the '2016, 03 th volume of automobile technology', wherein data analysis shows that when the battery is used under the conditions of DOD (20% -80%) and SOC (25% -75%), the charging alternating current internal resistance and the discharging alternating current internal resistance of the battery are both slightly increased by about 25% in the charging and discharging processes, the charging and discharging cycle is 500 weeks, the thickness and the alternating current internal resistance of the battery are only increased by about 3.78% and 2.08%, and the capacity is only attenuated by about 2.8%. However, in order to achieve the above purpose, the prior art adopts a low-voltage charger designed specially, which has poor compatibility, additionally increases the cost, and has no protection measure against deep discharge.

SUMMERY OF THE UTILITY MODEL

The utility model provides a battery charge-discharge protection device to solve the technical problem that current battery management can't guarantee battery life, compatibility are not enough.

In order to solve the technical problem, the utility model adopts the following technical scheme:

the design provides a battery charge-discharge protection device, including battery management module, a control module, a switch module, the partial pressure module, switch module and partial pressure module are parallelly connected and are formed first node and second node, first node is connected with the battery that is protected, discharge port/charge port are connected to the second node, battery management module's input and battery are connected, its output and control module's input correspond the connection, switch module includes the switch control end of corresponding the connection with control module, switch module switches on and can make the partial pressure module by the short circuit.

Further, the switch module is an NMOS type switch Q3, the drain thereof is connected to the first node, the source thereof is connected to the second node, and the gate thereof is the switch control terminal.

Furthermore, a low-power-consumption driving circuit is connected between the control module and the NMOS type switching tube Q3, an output end of the driving circuit is connected with a gate of the NMOS type switching tube Q3, and an input end of the driving circuit is connected with an output end of the control module.

Furthermore, the voltage division module is a diode, the anode of the diode is connected with the second node, and the cathode of the diode is connected with the first node.

Furthermore, the output end of the battery management module is connected with a charging switch and a discharging switch, the charging switch comprises a charging control end and a charging path, the discharging switch comprises a discharging control end and a discharging path, the charging control end and the discharging control end are connected to the output end of the battery management module, and the charging path and the discharging path are connected and arranged between the battery and the first node.

Further, the charging switch is a MOS transistor Q1, and the discharging switch is a MOS transistor Q2.

Further, the control module comprises a USB interface and an SMBUS interface. The USB interface is used for connecting a computer updating program, the SMBUS interface outputs battery information, and a charger or electric equipment (such as a camera) can read the battery information through the SMBUS.

Compared with the prior art, the utility model has the beneficial technical effects of:

1. the utility model discloses the MOS pipe and the diode that the microcontroller and the controller that set up the management chip communication in and the battery are connected can accomplish the function that the low pressure charges, and the user need not to change the charger, just can realize promoting the demand in battery life-span, and is compatible strong.

2. The utility model discloses based on impedance tracking technology, optimize the design of coulometer parameter, improve 0 capacity voltage threshold of group battery and discharge cut-off voltage threshold, in extension battery life, also can ensure that the group battery is discharged to 0% in-process by 100%, the slope of discharging of real-time capacity and percentage under the constant power mode is unanimous, prevent that the single electric quantity that improves the group battery that discharges the cut-off voltage and lead to from pointing out the serious deviation, the phenomenon that influences end user's experience such as the capacity decline is too fast appears in the last stage of the process of discharging, avoid causing the terminal equipment trouble such as unusual shutdown.

Drawings

Fig. 1 is a circuit diagram of the battery charging and discharging protection device of the present invention.

Fig. 2 is the circuit diagram of the intelligent battery management circuit of the present invention.

Fig. 3 is a circuit diagram of the MOS driving circuit of the present invention.

Detailed Description

The following embodiments are only intended to illustrate the present invention in detail, and do not limit the scope of the present invention in any way.

The programs referred to or relied on in the following embodiments are all conventional programs or simple programs in the art, and those skilled in the art can make routine selection or adaptation according to specific application scenarios.

The unit modules, components, structures, mechanisms, sensors, and other devices referred to in the following examples are all conventional commercially available products unless otherwise specified.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present application. References to "first," "second," etc. in this application are intended to distinguish between similar items and not necessarily to describe a particular order or sequence.

Example 1: a battery charge-discharge protection device, see fig. 1, intelligent battery management circuit BQ40Z50, the input end connects the group battery, is used for obtaining the voltage and the internal resistance of group battery, two upper outputs connect and charge MOS (Q1) and discharge MOS (Q2) respectively, the output of the right side connects the input of the microcontroller, the output of the microcontroller connects the input of the MOS drive circuit, the output of the MOS drive circuit connects the grid of the main loop switch Q3. The MOS transistor Q3 is connected with the diode D1 in parallel, the drain electrode of Q3 is connected with the negative electrode of D1 to form a first node, the source electrode of Q3 is connected with the positive electrode of D1 to form a second node, the first node is connected with the source electrode of Q2, and the second node is connected with the power supply port PACK +. The SMBUS communication interface of the microcontroller is connected with the charger or the electric equipment, and battery information acquired by the intelligent battery management circuit is output.

The microcontroller adopts an STM32F103RCT6 singlechip, has a low power consumption mode, has a USB function, and can be connected with a computer USB interface to directly update programs.

The Q3 is an NMOS transistor IRFH7004, and needs a dedicated driver LTC7004 for NMOS, as shown in fig. 3, the on-resistance of NMOS is smaller, and therefore, the device is more suitable for application scenarios of large current discharge. D1 uses a low forward voltage schottky diode because a proper forward voltage drop can achieve a desired full charge voltage and a low forward voltage drop can reduce heat generation during charging.

When the battery voltage is too low and charging is needed, a standard charger is used for starting charging, the Q3 is normally switched on, and the on-resistance of the Q3 is much smaller than that of the diode D1, namely the diode D1 is short-circuited; the microcontroller reads battery pack information from the intelligent battery management circuit in real time, and after the battery pack is charged to a set voltage value, the microcontroller sends an instruction to disconnect Q3 through the MOS drive circuit 1 and switch to diode bypass charging. And the voltage drop of the forward conduction of the diode is a fixed value, the charging current is not influenced, and if a resistor and other conventional voltage division devices are adopted, the voltage drop of the resistor is changed greatly along with the change of the charging current, so that the power supply cannot be completed. When the current is 0 when the battery pack is fully charged, the voltage drop across the resistor is also 0, and the purpose of reducing the charging voltage for the battery pack is not achieved.

The intelligent battery management circuit improves the discharging undervoltage protection threshold of the battery pack, and when discharging reaches the set threshold, the Q2 is closed to avoid over-discharging of the battery. By reducing the charging overvoltage protection threshold of the battery pack, when the battery pack is charged to the set threshold, the Q1 is turned off to avoid overcharging the battery.

Example 2: the battery pack is formed by connecting 4 lithium ion batteries in series (the battery cell model is NCR18650GA under the pine, and the nominal voltage is 3.6V), PSMN1R5-30YLC is used for Q1 and Q2 (Vds is 30V, and the on resistance is 1.55m omega), PMEG060V100EPD is used for D1 (forward voltage drop is 0.325V at 1A), IRFH7004 is used for Q3 (Vds is 40V, and the on resistance is 1.1m omega), PCAK + charging voltage is 16.8V, the discharging under-voltage protection threshold value set by the intelligent battery management circuit is 11V, and when the battery voltage is lower than 11V in the discharging process, Q2 is turned off to prevent over-discharging. At the charge overvoltage protection threshold of 16.5V, when the battery voltage during charging is higher than 16.5V, Q1 is turned off to prevent overcharging. When the intelligent battery management circuit detects that the battery voltage is 16.4V, indicating that charging is about to be completed, the Q3 is cut off to take down charging to prolong the service life of the battery.

Before use, the internal configuration parameters of the BQ40Z50 need to be corrected, specifically: A. the battery was charged using PACK +16.8V, with the charge rate set to 0.2C, to a current of less than 0.2A, and then left on hold for 2 h. B. Then, the discharge was started, the discharge rate was set to 0.2C, the discharge was stopped after the discharge reached the end voltage, and then the battery was left to stand for 5 hours. The steps A and B are collectively called 1 cycle, and after the battery is subjected to 2 cycles, the internal configuration parameters of the BQ40Z50 are corrected. If the discharge cut-off voltage is simply increased, the electric quantity indication of the battery pack can have serious deviation, and the phenomenon that the terminal user experience is affected by too fast capacity reduction and the like occurs at the end of the discharge process, even faults such as abnormal shutdown of the terminal equipment are caused. After the parameter configuration method is adopted, the capacity voltage threshold value 0 and the discharge cut-off voltage threshold value of the battery pack are improved, the service life of the battery is prolonged, and meanwhile, the consistency of the real-time capacity and the percentage discharge slope in the constant power mode can be ensured in the process that the battery pack is discharged from 100% to 0%.

The present invention has been described in detail with reference to the accompanying drawings and embodiments, but those skilled in the art will understand that various specific parameters in the above embodiments can be changed without departing from the spirit of the present invention to form a plurality of specific embodiments, which are the common variation ranges of the present invention and will not be described in detail herein.

Claims (7)

1. The utility model provides a battery charge-discharge protection device, its characterized in that, includes battery management module, control module, switch module, partial pressure module, switch module with partial pressure module connects in parallel and forms first node and second node, first node is connected with the battery of protection, discharge port/charge port are connected to the second node, battery management module's input with the battery is connected, its output with control module's input corresponds the connection, switch module include with control module corresponds the on-off control end of connecting, switch module switches on and can make partial pressure module is short-circuited.

2. The battery charging and discharging protection device as claimed in claim 1, wherein the switch module is an NMOS type switch Q3, the drain thereof is connected to the first node, the source thereof is connected to the second node, and the gate thereof is the switch control terminal.

3. The battery charging and discharging protection device as claimed in claim 2, wherein a low power consumption driving circuit is connected between the control module and the NMOS type switch Q3, an output terminal of the driving circuit is connected to the gate of the NMOS type switch Q3, and an input terminal of the driving circuit is connected to the output terminal of the control module.

4. The battery charging and discharging protection device according to claim 1, wherein the voltage dividing module is a diode, the anode of which is connected to the second node, and the cathode of which is connected to the first node.

5. The battery charging and discharging protection device as claimed in claim 1, wherein the output terminal of the battery management module is connected to a charging switch and a discharging switch, the charging switch comprises a charging control terminal and a charging path, the discharging switch comprises a discharging control terminal and a discharging path, the charging control terminal and the discharging control terminal are connected to the output terminal of the battery management module, and the charging path and the discharging path are connected and disposed between the battery and the first node.

6. The battery charging and discharging protection device as claimed in claim 5, wherein the charging switch is a MOS transistor Q1, and the discharging switch is a MOS transistor Q2.

7. The battery charge and discharge protection device of claim 1, wherein the control module comprises a USB interface and an SMBUS interface.

Images