CN212085842U

CN212085842U - Battery charging balance and overvoltage alarm circuit

Info

Publication number: CN212085842U
Application number: CN202020727065.7U
Authority: CN
Inventors: 俞峰; 杨麒麟; 刘斌生; 张凤敏
Original assignee: Fujian Scud Power Technology Co Ltd
Current assignee: Fujian Scud Power Technology Co Ltd
Priority date: 2020-05-07
Filing date: 2020-05-07
Publication date: 2020-12-04
Anticipated expiration: 2030-05-07

Abstract

The utility model relates to a battery charge balance and overvoltage warning circuit. The battery detection end of each charge balance and overvoltage alarm circuit is respectively connected with each single battery in the battery pack in series; the charging balance and overvoltage warning circuit comprises a single chip microcomputer, a three-terminal voltage regulator tube, a photoelectric coupler, a light emitting diode, first to sixth resistors and a field effect tube, wherein the second resistor and the three-terminal voltage regulator tube provide reference voltage, the single chip microcomputer performs battery voltage detection, indication and control functions, the light emitting diode and the third resistor indicate a balance working state, the fourth resistor and the photoelectric coupler play a role in battery overvoltage warning, and the field effect tube, the fifth resistor and the sixth resistor play a role in balance discharging. The utility model discloses the circuit is favorable to accomplishing all battery cell's in the group battery voltage balance, guarantees that all battery cells are not overcharged, has improved the security to the whole life-span that makes the group battery can prolong.

Description

Battery charging balance and overvoltage alarm circuit

Technical Field

The utility model relates to a battery charge balance and overvoltage warning circuit mainly is applied to the group battery that multisection battery series connection used, adopts an independent charge balance and overvoltage warning circuit to be connected with every section battery cell when charging, makes every battery cell in the group battery when the completion of charging, all reaches preset voltage value to reach the purpose of charge balance, and make battery cell have the protective action that overvoltage warning output control when being overcharged.

Background

With the rapid development of the battery industry, the application of a plurality of series-connected batteries is increasing, for example, in the fields of electric bicycles, electric automobiles, energy storage systems, communication backup battery packs and the like. When the batteries are used in series, due to the inconsistency of the batteries, the charge states of the battery pack are inconsistent and balance is lost, and the battery pack is overcharged and is not fully charged; when the battery pack discharges, overdischarge easily occurs to an unfilled battery cell to cause service life attenuation aggravation or safety problems, so that the whole service life of the battery pack is greatly shortened, and therefore, when the battery pack with multiple series-connected battery packs is not balanced and used, the service life of the battery pack is short, and the safety problems easily occur. Almost all lead-acid battery packs and part of lithium ion battery packs in the current market are not provided with a charge balance system during charging, and the balance scheme adopted by most of the battery packs with the charge balance system is passive balance and is realized by a special chip for detecting the front end voltage of a battery management system.

The existing battery balancing method realized by a battery management system front-end analog detection chip (AFE chip for short) in the market is characterized by small balancing current, low voltage precision (generally +/-20 mV) of balance control and low balancing efficiency, when the consistency of single batteries is poor, a good balancing effect cannot be achieved, and a balancing circuit has no indication function during working, and the balancing circuit does not have the function of single battery overvoltage alarm.

Disclosure of Invention

An object of the utility model is to provide a battery charge balance and overvoltage warning circuit is favorable to accomplishing all battery cell's in the group battery voltage balance, guarantees that all battery cell are not overcharged, has improved the security to the whole life-span that makes the group battery can prolong.

In order to achieve the above purpose, the technical scheme of the utility model is that: a battery charge balance and overvoltage warning circuit comprises a plurality of charge balance and overvoltage warning circuits, wherein the battery detection end of each charge balance and overvoltage warning circuit is respectively connected with the two ends of each single battery connected in series in a battery pack; the charging balance and overvoltage warning circuit comprises a single chip microcomputer, a three-terminal voltage regulator tube, a photoelectric coupler, a light emitting diode, first to sixth resistors and a field effect tube, wherein the second resistor and the three-terminal voltage regulator tube provide reference voltage, the single chip microcomputer performs battery voltage detection, indication and control functions, the light emitting diode and the third resistor indicate a balance working state, the fourth resistor and the photoelectric coupler play a role in battery overvoltage warning, and the field effect tube, the fifth resistor and the sixth resistor play a role in balance discharging.

In an embodiment of the present invention, the device further includes a diode, a first capacitor, and a second capacitor; the connection structure of the charge balance and overvoltage alarm circuit is as follows: the anode of the diode D1, the source of the field effect transistor V1, one end of the fifth resistor R5, the cathode of a light emitting tube of the photoelectric coupler N3, one end of the second capacitor C2, the grounding pin of the singlechip N2, the anode of the three-terminal voltage regulator N1 and one end of the first capacitor C1 are connected with the cathode of the single battery; the cathode of the diode D1, one end of the sixth resistor R6, the anode of the light emitting diode H1, the power pin of the singlechip N2, the other end of the second capacitor C2 and one end of the first resistor R1 are connected with the anode of the single battery; the other end of the first capacitor C1, the other end of the first resistor R1 and a GP3 pin of the singlechip N2 are connected; the adjusting end of the three-terminal voltage-regulator tube N1, one end of the second resistor R2, a GP4 pin of the singlechip N2 and the negative electrode of the three-terminal voltage-regulator tube N1 are connected; the GP5 pin of the singlechip N2 is connected with the other end of the second resistor R2; a GP2 pin of the singlechip N2 is connected with one end of a fourth resistor R4; the GP1 pin of the singlechip N2, the other end of the fifth resistor R5 and the grid of the field effect transistor V1 are connected; a GP0 pin of the singlechip N2 is connected with one end of a third resistor R3; the other end of the fourth resistor R4 is connected with the anode of a light-emitting tube of a photoelectric coupler N3; the other end of the third resistor R3 is connected with the cathode of the light-emitting diode H1; the collector of the photoelectric coupler N3 is used as an alarm output positive terminal; an emitter of the photoelectric coupler N3 is used as a negative alarm output terminal, and one end of the sixth resistor R6 is connected with a drain electrode of the field effect transistor V1.

In an embodiment of the present invention, the device further comprises a power supply, a charger, and a relay; the positive end of the alarm output of each charge balance and overvoltage alarm circuit is connected to the positive electrode of the power supply, the negative end of the power supply is connected to GND, the negative end of the alarm output of each charge balance and overvoltage alarm circuit is connected to one end of the relay control coil, the other end of the relay control coil is connected to GND, one end of the relay normally closed switch is connected with the positive electrode of the charger, the other end of the relay normally closed switch is connected with the positive electrode of the battery pack, and the negative electrode of the battery pack is connected with the negative electrode of the charger.

Compared with the prior art, the utility model discloses following beneficial effect has: the utility model discloses a charge balance and excessive pressure warning circuit's characteristics are that balanced voltage precision is high, balanced current is big, have that balanced state instructs and overvoltage warning signal output function, every battery balancing circuit is independent working circuit, does not receive the restriction of battery series quantity, can be applied to in the group battery of dozens of strings or even hundreds of strings. The circuit is favorable for completing the voltage balance of all the single batteries in the battery pack after the charging is finished, ensures that all the single batteries are not overcharged, improves the safety, and prolongs the whole service life of the battery pack.

Drawings

Fig. 1 is a circuit diagram of the battery charge balance and overvoltage alarm circuit of the present invention.

Fig. 2 is a circuit diagram of the present invention with specific circuit parameters for each single battery.

Fig. 3 is an applied circuit diagram of the whole battery pack system of the present invention.

Detailed Description

The technical solution of the present invention will be specifically described below with reference to the accompanying drawings.

The utility model provides a battery charge balance and overvoltage warning circuit, which comprises a plurality of charge balances and overvoltage warning circuits, wherein the battery detection end of each charge balance and overvoltage warning circuit is respectively connected with the two ends of each single battery connected in series in a battery pack; the charging balance and overvoltage warning circuit comprises a single chip microcomputer, a three-terminal voltage regulator tube, a photoelectric coupler, a light emitting diode, first to sixth resistors and a field effect tube, wherein the second resistor and the three-terminal voltage regulator tube provide reference voltage, the single chip microcomputer performs battery voltage detection, indication and control functions, the light emitting diode and the third resistor indicate a balance working state, the fourth resistor and the photoelectric coupler play a role in battery overvoltage warning, and the field effect tube, the fifth resistor and the sixth resistor play a role in balance discharging.

The circuit also comprises a diode, a first capacitor and a second capacitor; the connection structure of the charge balance and overvoltage alarm circuit is as follows: the anode of the diode D1, the source of the field effect transistor V1, one end of the fifth resistor R5, the cathode of a light emitting tube of the photoelectric coupler N3, one end of the second capacitor C2, the grounding pin of the singlechip N2, the anode of the three-terminal voltage regulator N1 and one end of the first capacitor C1 are connected with the cathode of the single battery; the cathode of the diode D1, one end of the sixth resistor R6, the anode of the light emitting diode H1, the power pin of the singlechip N2, the other end of the second capacitor C2 and one end of the first resistor R1 are connected with the anode of the single battery; the other end of the first capacitor C1, the other end of the first resistor R1 and a GP3 pin of the singlechip N2 are connected; the adjusting end of the three-terminal voltage-regulator tube N1, one end of the second resistor R2, a GP4 pin of the singlechip N2 and the negative electrode of the three-terminal voltage-regulator tube N1 are connected; the GP5 pin of the singlechip N2 is connected with the other end of the second resistor R2; a GP2 pin of the singlechip N2 is connected with one end of a fourth resistor R4; the GP1 pin of the singlechip N2, the other end of the fifth resistor R5 and the grid of the field effect transistor V1 are connected; a GP0 pin of the singlechip N2 is connected with one end of a third resistor R3; the other end of the fourth resistor R4 is connected with the anode of a light-emitting tube of a photoelectric coupler N3; the other end of the third resistor R3 is connected with the cathode of the light-emitting diode H1; the collector of the photoelectric coupler N3 is used as an alarm output positive terminal; an emitter of the photoelectric coupler N3 is used as a negative alarm output terminal, and one end of the sixth resistor R6 is connected with a drain electrode of the field effect transistor V1.

The device also comprises a power supply, a charger and a relay; the positive end of the alarm output of each charge balance and overvoltage alarm circuit is connected to the positive electrode of the power supply, the negative end of the power supply is connected to GND, the negative end of the alarm output of each charge balance and overvoltage alarm circuit is connected to one end of the relay control coil, the other end of the relay control coil is connected to GND, one end of the relay normally closed switch is connected with the positive electrode of the charger, the other end of the relay normally closed switch is connected with the positive electrode of the battery pack, and the negative electrode of the battery pack is connected with the negative electrode of the charger.

The following is the specific implementation process of the present invention.

The utility model discloses every series battery of circuit in with the group battery all is connected with an independent charge balance and warning circuit, this circuit uses a low-cost small-size singlechip as the core, adopt three-terminal accurate stabilivolt 431 for the voltage detection benchmark, the function that has the drive power pipe and discharge and instruct the battery, can export alarm signal through isolated optoelectronic coupler when the battery cell overvoltage simultaneously, when using this circuit, when charging the completion, all batteries all can reach preset voltage value, reach the balanced full-equipped purpose of battery, when the battery cell overvoltage condition takes place, the alarm signal of output can make outside charging system turn-off charge circuit, the group battery charging security has been improved.

As shown in fig. 1, the charge balancing and overvoltage warning circuit corresponding to each single battery is formed by connecting the following electronic components, namely a single chip microcomputer N2, a three-terminal voltage regulator tube N1, a photoelectric coupler N3, a voltage regulator diode D1, a light emitting diode H1, resistors R1-R6, capacitors C1 and C2, and a field effect tube V1. A resistor R2 and a three-terminal voltage regulator tube N1 in the circuit provide precise reference voltage; the single chip microcomputer N2 performs battery voltage detection, indication and control functions; the resistor R1 and the capacitor C1 are a reset end circuit of the single chip microcomputer; the voltage stabilizing diode D1 plays a role in protecting the singlechip from instantaneous overvoltage; the capacitor C2 plays a role in filtering high-frequency noise waves of the power supply end; the light-emitting diode H1 and the resistor R3 are used for indicating the balance working state; the resistor R4 and the photoelectric coupler play a role in battery overvoltage warning; the field effect transistor V1 and the resistors R5 and R6 are balance discharge circuits.

The connection relationship of the charge balance and overvoltage alarm circuit corresponding to each single battery is as follows: the anode of the diode D1, the source of the field effect transistor V1, one end of the resistor R5, the cathode of the light emitting tube of the photoelectric coupler N3, one end of the capacitor C2, the grounding pin of the singlechip N2, the anode of the three-terminal voltage regulator tube N1, one end of the capacitor C1 and the cathode of the battery are connected; the negative electrode of the diode D1, one end of the resistor R6, the positive electrode of the light-emitting tube H1, the power supply pin of the singlechip N2, one end of the capacitor C2, one end of the resistor R1 and the positive electrode of the battery are connected; one end of the capacitor C1, one end of the resistor R1 and a GP3 pin of the singlechip N2 are connected; the adjusting end of the three-terminal voltage-regulator tube N1, one end of the resistor R2, a GP4 pin of the singlechip N2 and the negative electrode of the three-terminal voltage-regulator tube N1 are connected; a GP5 pin of the singlechip N2 is connected with one end of a resistor R2; a GP2 pin of the singlechip N2 is connected with one end of a resistor R4; a GP1 pin of the singlechip N2, one end of a resistor R5 and the grid of a field effect transistor V1 are connected; a GP0 pin of the singlechip N2 is connected with one end of a resistor R3; one end of the resistor R4 is connected with the anode of the light-emitting tube of the photoelectric coupler N3; one end of the resistor R3 is connected with the negative electrode of the light-emitting tube H1; the collector of the photoelectric coupler N3 is connected with the CTRL pin of an external control signal; the emitter of the photoelectric coupler N3 is connected with the GND pin of an external control signal; one end of the resistor R1 is connected to the drain of the FET V1.

The working process of the battery charge balance and overvoltage alarm circuit is as follows: when the circuit is connected with a single battery, the single chip microcomputer is powered on to work, a GP5 pin of the single chip microcomputer N2 outputs high level, so that a three-terminal voltage regulator tube N1 is powered on to generate precise 2.5V reference voltage and is sent to a GP4 pin of the single chip microcomputer, the single chip microcomputer carries out AD conversion on the GP4 pin by taking power supply voltage (namely battery voltage) as AD conversion reference to obtain an AD conversion value, software conversion is carried out in the single chip microcomputer to calculate the battery voltage value, then the battery voltage value is judged, if the battery voltage is greater than 4.25V, the GP2 pin of the single chip microcomputer outputs high level to generate an alarm signal, and the alarm signal is released only when the battery voltage is less than 4.2V once generated; if the battery voltage is more than 4.2V, the GP1 of the single chip microcomputer is changed from low level to high level, the field effect transistor V1 is conducted, the battery discharges through the resistors R6 and V1, the GP0 of the single chip microcomputer is changed from high level to low level at the same time, the light emitting diode H1 emits light, and the balance circuit is prompted to work. If the battery voltage is lower than 4.2V, the GP0 keeps high level, the light emitting diode H1 is not lighted, meanwhile, the GP2 is low level, no alarm signal is generated, the GP0 keeps low level, the battery is not discharged, at this time, the single chip microcomputer enters a low power consumption sleep mode, the power consumption current is only dozens of uA in the low power consumption sleep mode, after the sleep mode lasts for a period of time (for example, 1 second), the single chip microcomputer is awakened by a watchdog, and the previous working process is continued.

Fig. 2 shows a practical circuit with specific circuit parameters for each battery cell, in which a PIC12F675 of MICROCHIP is used as a single chip microcomputer, a PC817 is used as a photoelectric coupler, an FDS9926 is used as a field effect transistor V1, a resistor R6 is a power resistor of 20 Ω, and parameters of other components are shown in fig. two.

Fig. 3 is a circuit diagram of an application of the whole battery pack system, which is illustrated by a battery pack with 4 batteries connected in series, and in practical applications, the number of batteries connected in series can be from 2 to several hundreds. Each single battery in the 4 series battery packs is connected with an independent and identical battery charge balance and overvoltage warning circuit, 2 warning output pins CTRL and GND of each circuit are all connected together, and a 5V direct-current power supply and a relay with 5V driving voltage are additionally arranged outside. Wherein the positive pole of the 5V direct current power supply is connected with CTRL; the GND pin is connected with one end of the relay coil; the other end of the relay coil is connected with the negative electrode of a 5V direct-current power supply; one end of the relay normally closed switch is connected with the positive electrode of the charger, and the other end of the relay normally closed switch is connected with the positive electrode of the charged battery pack; the negative pole of the battery pack is connected with the negative pole of the charger. In the charging process of the battery pack, if the voltage of a certain single battery exceeds 4.2V, a balancing circuit corresponding to the battery is started to discharge until the voltage is less than 4.2V, if the voltage of any battery exceeds 4.25V in the charging process, a circuit corresponding to the battery generates an overvoltage warning circuit, a light emitting tube of a photoelectric coupler emits light, CTRL and GND are driven to be conducted, a relay generates a suction action, and then a normally closed contact of the relay is disconnected, a charging loop is cut off, and the battery pack is prevented from being overcharged; when the voltage of the battery is less than 4.2V, the alarm circuit is released and returns to normal, and at the moment, the normally closed switch of the relay is turned on again, so that the battery can be charged again.

The utility model discloses the circuit is compared with trade internal balance circuit's performance, as shown in Table 1:

the utility model has the characteristics of it is following:

1. the balancing circuit is independently designed for each battery, each circuit is independently connected with each single battery, and the balancing circuit can be applied to any plurality of series-connected battery packs; 2. the voltage detection of the battery adopts a precise three-terminal voltage regulator tube as a voltage reference to provide the voltage reference for the singlechip to carry out AD conversion, the voltage precision of the battery can reach 5mV after software calibration, and the voltage precision of balance control is high; 3. the discharge circuit of the battery balance is driven by the singlechip to drive the power tube and the power resistor to work, can realize larger balance current and has the function of indicating the balance state; 4. the circuit is in an intermittent sleep state, and the average power consumption of the circuit can be lower; 5. the charge equalization circuit has an overvoltage warning function with isolated output by a photoelectric coupler, and the function can be applied to overcharge protection control of a battery pack.

Above is the utility model discloses a preferred embodiment, all rely on the utility model discloses the change that technical scheme made, produced functional action does not surpass the utility model discloses during technical scheme's scope, all belong to the utility model discloses a protection scope.

Claims

1. A battery charge balance and overvoltage warning circuit is characterized by comprising a plurality of charge balance and overvoltage warning circuits, wherein the battery detection end of each charge balance and overvoltage warning circuit is respectively connected with the two ends of each single battery connected in series in a battery pack; the charging balance and overvoltage warning circuit comprises a single chip microcomputer, a three-terminal voltage regulator tube, a photoelectric coupler, a light emitting diode, first to sixth resistors and a field effect tube, wherein the second resistor and the three-terminal voltage regulator tube provide reference voltage, the single chip microcomputer performs battery voltage detection, indication and control functions, the light emitting diode and the third resistor indicate a balance working state, the fourth resistor and the photoelectric coupler play a role in battery overvoltage warning, and the field effect tube, the fifth resistor and the sixth resistor play a role in balance discharging.

2. The battery charge balancing and overvoltage warning circuit of claim 1, further comprising a diode, a first capacitor, a second capacitor; the connection structure of the charge balance and overvoltage alarm circuit is as follows: the anode of the diode D1, the source of the field effect transistor V1, one end of the fifth resistor R5, the cathode of a light emitting tube of the photoelectric coupler N3, one end of the second capacitor C2, the grounding pin of the singlechip N2, the anode of the three-terminal voltage regulator N1 and one end of the first capacitor C1 are connected with the cathode of the single battery; the cathode of the diode D1, one end of the sixth resistor R6, the anode of the light emitting diode H1, the power pin of the singlechip N2, the other end of the second capacitor C2 and one end of the first resistor R1 are connected with the anode of the single battery; the other end of the first capacitor C1, the other end of the first resistor R1 and a GP3 pin of the singlechip N2 are connected; the adjusting end of the three-terminal voltage-regulator tube N1, one end of the second resistor R2, a GP4 pin of the singlechip N2 and the negative electrode of the three-terminal voltage-regulator tube N1 are connected; the GP5 pin of the singlechip N2 is connected with the other end of the second resistor R2; a GP2 pin of the singlechip N2 is connected with one end of a fourth resistor R4; the GP1 pin of the singlechip N2, the other end of the fifth resistor R5 and the grid of the field effect transistor V1 are connected; a GP0 pin of the singlechip N2 is connected with one end of a third resistor R3; the other end of the fourth resistor R4 is connected with the anode of a light-emitting tube of a photoelectric coupler N3; the other end of the third resistor R3 is connected with the cathode of the light-emitting diode H1; the collector of the photoelectric coupler N3 is used as an alarm output positive terminal; an emitter of the photoelectric coupler N3 is used as a negative alarm output terminal, and one end of the sixth resistor R6 is connected with a drain electrode of the field effect transistor V1.

3. The battery charge balancing and overvoltage warning circuit of claim 2, further comprising a power supply, a charger, a relay; the positive end of the alarm output of each charge balance and overvoltage alarm circuit is connected to the positive electrode of the power supply, the negative end of the power supply is connected to GND, the negative end of the alarm output of each charge balance and overvoltage alarm circuit is connected to one end of the relay control coil, the other end of the relay control coil is connected to GND, one end of the relay normally closed switch is connected with the positive electrode of the charger, the other end of the relay normally closed switch is connected with the positive electrode of the battery pack, and the negative electrode of the battery pack is connected with the negative electrode of the charger.