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Proteção de bateria PCB

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What is a battery protection circuit?

The circuit monitors the voltage of a Li-Ion battery and disconnects the load to protect the battery from deep discharge when the battery voltage drops below the lockout threshold.

Storing a battery-powered product in a discharged state puts the battery at risk of being completely discharged.

battery protection circuit
Do batteries have short circuit protection?

Do batteries have short circuit protection?

Protected Lithium-Ion (Li-ion) batteries have a small electronic circuit integrated into the cell packaging.

This circuit protects the battery against common dangers, such as overcharge, over discharge, short circuit/over current, and temperature.

How do I keep my battery from short circuiting?

Methods to protect against short circuit include, but are not limited to,   the following: Pack each battery or each battery-powered device when practicable, in fully enclosed inner packagings made of non-conductive material

How do I keep my battery from short circuiting?

Venture is a PCB manufacturer for more than 10 years. We are manufacturing all types of PCBs that include Battery Protection PCB.

We are one of the leading manufacturers in China.

As a leading manufacturer, we provide the best quality of Battery Protection PCBs at reasonable prices.


Your Leading Battery Protection PCB Supplier in China

Venture is a professional PCB manufacturer located in China. We are capable of manufacturing all kinds of PCBs and also PCBs for battery protection.

We have more than 10 years of experience in the PCB industry. We are providing PCB solutions for our customers from all over the world.

PCB or PCM ( protection circuit board or module ) is also called the “heart” of the Lithium battery pack.  This PCB will help protect the Lithium battery pack from over-discharging, overcharging, and over-drain. So, therefore, it is a must to avoid the Lithium battery pack from the damage, explosion, and fire.

To keep each cell in good service and balance in a low voltage battery packs, you should choose PCM with an equilibrium function.

Advances battery manage systems monitor each cell’s performance to ensure the safety of the battery operation, so for high voltage Lithium battery packs, you should consider the advanced battery manage system.

If you want to purchase, feel free to contact us and we will be happy to provide your needs.

Battery Protection PCB: The Ultimate FAQ Guide


Probably, you’re looking for a perfect battery protection PCB for your application.

A reason this guide will explore everything you need to know about battery protection PCB.

Continue lendo para aprender mais.

What Is The Role Of Battery Protection PCB?

Battery protection PCB will ensure that lithium-ion cells, that are in a series connection, have protection against the following:

Battery Protection PCB

Battery Protection PCB


The overcharge protection will prevent the lithium-ion from continuing to charge when it reaches a specific voltage.

The MOS tube controls overcharging and will change to an off state thereby stopping the charging process.

Descarga excessiva

The over-discharge protection will inhibit discharging the battery cell when the voltage becomes low.

The MOS tube controls the over-discharge and turns to an off state, and will inhibit discharging.

Excess Current Draw

The overcurrent protection will inhibit discharging the load when it draws a large current.

This function will protect batteries and MOS tubes and ensure the battery operates under safe working conditions.

When it detects overcurrent, battery goes back to normal state once it is separated from the load, and you can recharge or discharge.

Curto circuitos

This protection makes the battery safer by expelling the gas that short circuits generate. Also, it prevents the battery from inflating and exploding.

Mishandling lithium-ion batteries will damage them as they can emit gases or burst into flames or explode in extreme cases.

When you carefully charge the cells with specific intelligent chargers, they will be safe and out of risk.

Also, these cells will need protection from overcharging as the lithium-ion batteries will hold a charge between 4.2 volts and 3.1 volts.

Besides, when the voltage goes below 3 volts, the lithium-ion cells will be damaged permanently and will not operate optimally.

Some lithium-ion cells have protection circuitry to ensure the voltage does not dip below the minimum.

However, you cannot connect these cells in a series configuration when you need high voltage battery packs.

When you connect unprotected cells in a series formation, it is vital to have a protection circuitry.

The protection circuitry detects extreme and potentially damaging scenarios.

Why Is 18650 Battery Protection PCB Necessary?

These battery protection PCB have electronic circuits within the cell packing.

The circuit will protect the cell from short circuits, heat, over-discharging, and overcharging.

Besides, they are safer than Baterias 18650 with no protection.

Is There Difference Between Battery Protection Module And Battery Protection PCB?

You can classify battery protection boards into two categories.

These include the battery protection module otherwise known as battery protection PCB and the battery management system [BMS].

This means that the battery protection module and battery protection PCB are the same thing. They ensure that the battery is stable and does not pose any danger.

Lithium Battery Protection PCB

Lithium Battery Protection PCB

Which Are The Main Types Of Battery Protection PCB?

The two types of battery protection PCB are:

Voltage Protection PCB

The voltage protection will use comparators that will monitor independent cell voltages.

Also, it compares the individual cell voltages to various thresholds and detects if there is an under-voltage [UV] or overvoltage [OV] state.

Current Protection PCB

Here, there are a series of sense resistors that measure the current that passes via the batteries.

It will then compare the current to the predetermined undercurrent [UV] or overcurrent [OC] thresholds.

This will include short-circuiting scenarios, excessive charge, and discharge levels.

Are There Deep Discharge Protection PCBs?

Yes, deep discharge protection PCBs do exist. Deep discharging or overcharging happens when a battery that you discharge to its full capacity.

All batteries have cut-off points, a point where the battery has a complete discharge.

To conduct deep discharge protection, first identify the battery’s cut-off voltage level.

Then you will design a circuit that disconnects the load from batteries when the battery attains the cut-off voltage rate.

Some manufacturers will illustrate a cut-off voltage for certain discharge rates.

Besides, the cut-off voltage is sensitive to various discharge rates since high discharge rates lead to low cut-off voltages, and vice versa.

Moreover, the cut-off voltage is sensitive to working temperature.

The quantity of electric discharge is between 1.5 and 2 times more than the capacity of the battery in deep discharging.

This means it is difficult to recharge the battery due to an increase in internal resistance when the battery over discharges.

What Is The Difference Between Unprotected Vs Protected 18650 Battery?

18650 batteries are powerful hence you need to safely handle them.

Here is how unprotected and protected 18650 batteries compare:

Baterias 18650 protegidas

These batteries contain tiny electric circuits within the cell packing.

The circuit will protect the battery from elements such as temperature, overcharge, short circuit or overcurrent, and over-discharge.

Besides, protected batteries are safe for your application as they rarely catch fire. Also, protected batteries tend to cost more than unprotected batteries.

Baterias 18650 desprotegidas

These batteries do not contain an electronic circuit within the cell packing.

This feature makes them contain a higher capacity and current capability than protected batteries.

Besides, since they have no protection, there is the risk of short-circuiting, over-discharging, or overheating. Also, unprotected batteries are much affordable.

Where Is Battery Protection PCB Found In An Electronic?

The battery protection PCB, depending on the size and features of the battery pack and product, can be found:

  • Embedded in the charger
  • Attached permanently to the packs of the batteries

What Are The Main Components Of Battery Protection PCB?

Battery Protection circuit boards contain electronic circuits, battery core voltage, charging circuits, and discharging circuits.

The key normal Li-ion battery protection PCB components include:

  • ICs
  • capacitores
  • MOS
  • Resistores
  • Switches
  • Auxiliares
  • FUSE
  • NTC
  • ID NTC
  • memória

Battery Protection PCB Assembly

Battery Protection PCB Assembly

Control IC will control the MOS switch to remain on in normal operating conditions, and the external circuit and cell also turn on.

When the loop current or cell voltage goes beyond predetermined values, it controls the MOS switch.

The MOS switch will turn off hence protect the batteries.

Most protected batteries have the following parts:


This part protects the battery from overheating.

It will also indirectly protect the battery from over-current.

CID or Pressure Valves

These parts will permanently disable the battery when the pressure within the cell is too high.

The high pressure can be due to an over-charge.


Depending on the design, the PCB will protect the battery from overcharging, over-discharging, and overheating.

Also, the PCB resets automatically or when you place it in a charger.

Which Are The Possible Battery Protection PCB Designs?

The designs that you can find in battery protection PCB are:

Embedded In The Charger

This kind of design will protect the battery cells only when you connect them to a charger. The design will minimize the overall weight and size of the battery packs.

Also, this design is suitable when you need the battery pack to be lightweight yet functional.

Here are some advantages of having the battery protection PCB design embedded in the charger:

  1. You only require one protection circuit module
  2. It lowers costs when you plan to use several batteries. For instance, when the product can use non-lithium ion batteries which need no protection circuit when using or discharging

Some limitations of placing the protection circuit within the battery charge include:

  1. You cannot monitor the battery if you are using it when you do not connect the charger. This issue will increase the possibility of the temperature rising above the threshold, thus leading to overheating
  2. Also, the battery will have low performance and a short life cycle if you do not connect it. This is because you cannot monitor the battery when you do not connect the charger

Embedded In Battery Packs

When you embed the protection circuit within the battery packs, you have active and full-time protection in the entire lifecycle of the batteries.

This design is suitable for use in rechargeable lithium batteries and when you plan to use multiple cells in a battery pack.

The protection that is within the battery pack will perform the following:

  1. Monitor the cells of the batteries even if you are using different chargers
  2. It also improves the safety of the entire battery pack systems
  3. Monitoring of the fuel gauge
  4. Enhance the performance of the batteries which increase their shelf life

The disadvantages of embedding the protection in the battery packs include:

  1. Every battery will need a battery protection PCB
  2. When you combine the modules and depending on the cells you are using, the overall weight of the system will increase
  3. Depending on the space available, it is difficult to place the protection circuit board in unique battery packs and product designs
  4. Besides, when you increase the number of batteries and use complex designs, the overall cost will be high

Also, it is important to note that you can recoup the initial cost as the batteries have a longer life span and great performance

Why Are MOSFETs Important In A Battery Protection PCB Assembly?

For you to achieve high efficiency, you should use MOSFETs that have low RDS [ON].

Also, use MOSFETs with a lower Vt since battery protection ICs may contain 2 V to 3 V that drives the gates.

How Does Battery Protection PCB Detect Overheating?

Battery protection PCBs have a thermistor that senses temperature fluctuations and relay a warning when it senses overheating.

For thermistors, the resistance will vary with temperature.

What Is The Difference Between PTC And NTC Thermistor Component Of Battery Protection PCB?

PTC thermistors contain Positive Thermal Coefficient.

This means that the resistance will gradually increase with an increase in temperature.

When it reaches a limited range, the resistance will be linearly proportional to the temperature.

NTC thermistors contain a Negative Temperature Coefficient. This means an increase in temperature will decrease their resistance.

These parts are vital for monitoring and protecting the circuits to offer analog temperature voltage.

Also, it may provide control in circuits that will offer temperature compensation.

Besides, NTC thermistors can stop the charge or disconnect the batteries from the charger in high-temperature conditions when:

  • It reaches the temperature cut-off point
  • Turn on the cooling fans

For some usages, thermistors will provide communication between the environment and the batteries.

Also, battery protection PCB can use thermistors to evaluate the beginning environmental situation.

The thermistors will then inhibit charging when the temperature of the batteries is extremely high or low.

NTC thermistor Component of Battery Protection PCB

NTC thermistor Component of Battery Protection PCB

Which Are The Common Types Of ICs Used In Battery Protection PCB?

ICs assist in making it simple to deal with complex circuits and you need to regularly regulate the power for the load.

Also, ICs can monitor and control the flow of power.

There are two types of ICs that you can use in battery protection PCBs:


This is a high voltage, 2-input voltage monitor that is suitable for use in multi-cell battery applications.

The IC will continuously monitor the input voltage.

RST pins will go high if the voltage is low which indicates that the battery voltage is low. Besides, you can offer either an inverting or a non-inverting to the ICs.

The LTC2960 will offer the following:

  1. Monitoramento de energia
  2. Controlling the power
  3. Protection of mobile battery-powered devices, etc.


This IC is a low-power op-amp that will operate in a very low current supply.

Besides, you can use the LT1495 in low current supplies of 3 V, 5 V, and +/- 15 V.

Also, it will offer up to 18 V of reverse battery protection and can control a broad voltage range of 2.2 V to 36 V.

LT1495 has the main advantage in that it uses another protection circuit that needs a high current.

Concurrently, the circuit that makes use of LT1495 will require a current supply of less than 4.5uA.

What Is The Role Of Fuel Gauge In Battery Protection PCB?

Fuel gauges are circuits that determine the amount of energy that is available in the battery at any time.

Gauging circuits will monitor the current, temperature and voltage of the batteries. It will then digitize the values from these aspects in one or several ADCs.

After digitizing the values, it relays them to either the:

  • Onboard microcontrollers
  • Dedicated logic controllers

The firmware within the controller will inspect the gauging algorithms then determine the battery’s situation or state.

How Do You Make A Simple Battery Protection PCB?

Before beginning to make the battery protection PCB, you will need the following components:

  • One LM393 IC
  • One BC547 transistor
  • One 5V Zener diode
  • Two 1N4007 diodes
  • Um LED
  • Two 1K resistor
  • One 4.7K resistor
  • One 47k resistor
  • One 10K Trimpot
  • One 100uF capacitor
  • One 12V relay
  • Two 2-pin terminal blocks
  • Perf board
  • Fios de ligação

Begin by connecting the LM393 IC to the perf board. Pin number 4 should connect to the ground and pin number 8 to the positive supply.

Then connect the 10K trim pot to pin number 2 of the IC and pin number 3 to ground. Proceed to connect pin number 3 of the IC to the positive supply.

Connect 5V Zener diode to pin number 3 of the IC and its anode to the ground. Then connect the 4.7K resistor to the remaining pin of the 10K trim pot and positive supply.

Connect the cathode of one 1N4007 diode to pin number one of the IC.

Proceed to connect the positive pin on the 100uF capacitor to pin number 2 of the IC and its negative pin to the ground.

Afterwards, Connect BC547 transistor and its pin number 2 to the anode of 1N4007 diode and its pin number 3 to ground.

Then, connect the 47K transistor to pin number 2 of the BC547 transistor and positive supply. Connect the 12V relay and its one coil pin and closed pin to the positive supply.

Install the other coil to pin number one of the BC547 transistor.

Proceed to connect one 1N4007 diode and its cathode to a positive supply and anode to pin number one of the BC547 transistor.

Connect the cathode of the LED to the ground. Then connect 1K resistor to positive supply on the anode of the LED.

Connect 2 pin terminal block and its pin number one to common pin of the relay and pin number 2 to ground.

Finally, connect another 2 pin terminal block and its pin number 1 to the positive supply and pin number 2 to the ground.

Use jumper cables to test the device before operating.

What Is The Operating Principle Of Battery Protection PCB Assembly?

Here is how the battery protection PCB assembly operates:

Battery Protection PCB Schematic

Battery Protection PCB Schematic

Activation Of The Protection Board

If Protection board P- and P+ in the protection state are not output, short circuit B- and B+ to activate the board.

Then the levels of the COUT and DOUT will be low and the two ports of the IC are high and low-level protections.


Connect the chargers’ positive pole and the negative pole to the P+ and P- respectively. Current will pass via the two MOS and charge the batteries.

Also, the protection IC’s VSS and VDD are power supply and cell voltage detection terminals. The voltage of the cells will increase during the charging process.

The COUT inputs high levels and turn off the MOS switch when the voltage reaches the cells’ protection voltage.

This action turns off the charging circuit and the cell voltage drops following overcharge protection.

COUT will return to low levels and turns on the MOS tune when voltage dips to the IC’s overcharge protection recovery voltage.


As the battery discharges, the IC’s VSS and VDD detect cell voltage.

The DOUT will output high levels to shut off MOS transistors when cell voltage dips to the IC overcharge protection voltage.

This effect will disconnect the discharge circuit, and the voltage of the cells rises after over-discharge protection.

The DOUT recedes to low levels and opens the MOS switch when the voltage reaches its threshold.

Short Circuit And Over Current

There is internal resistance when MOS gets saturated and conductive due to the main current being high during the discharge process.

This means the voltage will drop on both ends of the MOS tube when the current flows across P- and B-.

The effect will protect the IC’s V- and VSS as the system detect voltage on both ends.

DOUT will emit high levels and shut off MOS tubes to disconnect the circuits when the voltage rises to the ICs detection threshold.

Purpose of NTC Port

Problems such as overcurrent, over-discharge, and overshoot are absent as the battery operates.

Also, since the working duration is long, temperature rises in battery cells and the NTC will monitor the temperature levels.

Resistance of NTCs will decrease gradually following an increase in temperature.

The CPU commands the system to turn off and stop charging when the resistance dips to a certain value. This effect will protect the batteries.

Which Are The Two Important Considerations When Selecting A Battery Protection PCB?

The two vital aspects when selecting battery protection PCB are the under-voltage threshold and the overvoltage threshold. These digits are the limit of the voltage at which the IC cuts the circuit when the cell experiences an overcharge or over-discharge.

Besides, these digits are included in the ICs battery protection.

Overvoltage Protection Threshold

Lithium batteries, when you charge them to 4.2 V, contain more charge in every charge cycle. Besides, when you charge them to 4.1 V, it makes them have a longer lifespan.

Design engineers need to balance charge per cell and longevity when selecting overcharge voltage thresholds.

Over-Discharge Protection Threshold

This threshold will impact the cell life and the charge or capacity.

Discharging a battery all the way makes it contain more charge after every charge.

Besides, this effect is stressful and will lower the lifetime of these batteries.

What Is The Recommended Voltage Protection Accuracy Of Battery Protection PCB?

The recommended voltage protection accuracy is ±10 mV. The overvoltage range is between 3 V and 4.575 V while under-voltage is between 1.2 V and 3 V

Can You Reset Battery Protection PCB?

Many battery protection PCBs are resettable and you can make them not resettable in fail-safe conditions.

What Is The Charging Voltage And Quiescent Current Of Battery Protection PCB?

Quiescent current refers to a state of the circuit when it is driving no load and the inputs are not cycling.

A lower quiescent current will increase the lifespan of the batteries. The quiescent current should be lower than 50uA.

Charging voltage is the recommended voltage that you can apply to a battery to charge without damaging it. The charging voltage can be between 12.6 V and 13 V.

How Does Protection Circuit Module (PCM) And Battery Management System (BMS) Compare?

Veja como esses dois se comparam:

Protection Circuit Module [PCM]

Battery Protection Circuit Module

Battery Protection Circuit Module

This is a stand-alone battery protection circuit. Besides, it is analogical which means there is no software within it.

Also, you cannot turn off or turn on the battery pack. PCM will not allow you to monitor the specific status of the charge level in the battery pack.

Also, PCM will not control charging units or consuming units. This module will seldom take surveys of the temperature of the battery packs.

Also, it will equalize in a basic level the various elements of the application. Besides, PCMs are affordable.

The basic applications that use PCM are low-cost products such as electrically-assisted bikes, or small electric devices.

Battery Management System [BMS]

This system is advanced than a PCM as it has software integrated microcontrollers in it.

BMS will calculate and interpret measurements such as state of charge [SOC] or state of health [SOH].

Also, it offers various protection levels, for instance, it distinguishes abnormal and normal scenarios relating to time.

It allows for the transfer of information as it has a communication bus [MODBUS, CAN, etc.].

The main application can steer a BMS.

It can communicate with other BMS thereby forming large capacity batteries as it automatically adapts to various requirements.

Also, it can optimize energy consumption by going to standby modes.

To equalize various elements of the application, it makes use of intelligent algorithms.

It also steers chargers or consuming units through its communication bus, thereby optimizing battery usage and system behavior. At any moment, BMS can perform a full diagnosis on the batteries.

Besides, BMS can record and store information relating to the battery such as storage time, counting errors, or usages.

Advanced products such as drones, electric bikes, robots, electric vehicles, will use a BMS.

Which One Should You Should You Choose Between PCM Vs BMS?

The application and security level will determine if you should choose between a BMS and PCM.

You can select a PCM if you are using low-cost products where durability and autonomy of the batteries are not vital.

When you need more secure levels, good energy management, and monitoring, a BMS is a correct choice.

Also, use a BMS when the product you are making will end in the hands of the public.

What are The Likely Problems You Will Experience When You Don’t Use Lithium-Ion Battery Protection PCB?

These problems include the following:

Death Of Cell

This happens when the discharge of the batteries dips below a specific threshold.

Thermal Runway

This effect happens due to over-heating or over-charging. Overheating will begin when the ambient temperature rises, or you use a high current when charging or discharging.

Thermal runways will damage and also cause fire hazards.

Load Device Damage

This occurs when there is a faulty inrush current or reversal of the battery polarity.

Which Are The Battery Parameters That You Can Monitor Using Battery Monitoring Systems (BMS)?

Esses incluem:

  • Voltagem such as total voltage or voltage of independent cells
  • Temperaturas such as the temperature of independent cells or average temperature
  • Profundidade de descarga [DOD] or State of charge [SOC] that shows the level of charge
  • State of health [SOH] which is the overall condition of the batteries
  • Atual that enters and exits the battery

What Are The Advantages Of 18650 Battery Protection PCB?

Esses incluem:

  • Ampla gama de aplicações
  • You can form a series connection
  • Small internal resistance
  • Alta voltagem
  • Sem efeito de memória
  • Desempenho de alta segurança
  • Grande capacidade
  • Longa vida útil

18650 Battery Protection PCB

18650 Battery Protection PCB

Which Are The Important Specification Of Battery Protection PCB To Consider When Placing An Order?

Esses incluem:

  • Temperatura de trabalho
  • Resistência interna
  • Maximum operating and transient current
  • Condições de armazenamento
  • corrente de repouso
  • Tensão de carregamento
  • Proteção contra curto-circuito
  • Vida efetiva
  • Over-voltage and over-discharge voltage range

What Is The Cost Of Battery Protection PCB?

You can purchase a battery protection PCB for as low as 3 USD.

Depending on your specific requirements, we offer a range of battery PCBs such as 18650 placa de suporte de bateria, 18650 PCB do carregador de bateria e PCB carregador de bateria.

Contacte-nos agora for all your battery protection PCBs.

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