When the BBU reference that exploring ADI is designed, be necessary to understand the working principle of BMS. BMS is in charge of monitor and adjusting the state of batteries, ensure batteries moves inside safe parameter. Include to monitor batteries piles voltage, batteries to pile level of electric current of temperature and batteries caboodle whole among them, and government charges and discharge is periodic. Dovish BMS can make the system achieves ideal efficiency and security. Prolong battery life crucial to managing peak value property. Frequent overcharge or excessive discharge fall in unwitting circumstance, can damage batteries health, shorten battery service life. The health through monitoring batteries carefully (SOH) is used correctly, can avoid batteries accident to shut or breakdown, make batteries develops good performance.

In addition, the integral health condition that the SOC of surveillant batteries piles to batteries is very fundamental. As the elapse of time, batteries is met loss capacity, and n is extinct the loss that accelerates batteries capacity to 0 meetings. The good method that prolongs battery life is battery n carries be in 20% to 80% between. The SOC that understands batteries can ensure BBU module moves continuously longer.

Besides SOH and SOC, still must know discharge depth better (DOD) . DOD is to use charge a when the consideration needs when batteries main factor. It is the batteries capacity percentage that in showing in sheet second discharge circulates, spends. Generally speaking, to prolong batteries whole life, the proposal avoids to reach batteries discharge 20%DOD is the following. However, a few batteries can bear of later rate discharge and won’t cause apparent damage. Inquire the guideline of manufacturer without fail, understand the proposal of specific discharge deepness of specific batteries.

In addition, think carefully the chemical character of batteries is crucial. In the design of BBU module, use lithium is ionic (the choice that Li-ion) batteries is a discretion. Because it already got be used extensively,selecting lithium ion battery is, with OCPORV3 normative requirement agrees completely. The backside reason of this kind of consistency depends on the good character of lithium ion batteries, namely outstanding energy density and very light weight. Notable is, the chemical composition that studies lithium ion batteries deep announced a crucial fact: The chemical composition of lithium ion batteries is a complex crucial factor, the function that deciding batteries from beginning to end, security and whole are durable quality.

Another respect that needs a consideration is batteries balance. Batteries is a of batteries technology domain main idea evenly. Increase ceaselessly as the demand to efficient, high-powered batteries, the batteries that realizes ideal becomes more and more important evenly. Batteries is the process of the voltage that points to each batteries inside balanced batteries bag or SOC evenly. In the batteries package that includes many battery, every batteries has respective and unique character, and the elapse as time, batteries function may produce change. Production tolerance, batteries contains the element such as quantity change and use mode difference, cause cell possibly lopsided. These lopsided likelihoods cause batteries total capacity to decrease, loss of efficiency, even batteries includes premature be no longer in force. Relevant design has a passive balancer on requirement BBU. Accordingly, be involved to use resistor to come by dynamic balancing release or the redundant energy in using up the batteries with tension higher level. This kind of method is relatively simple and economy is efficient, but can bring about energy loss and generation of quantity of heat. Batteries can ensure batteries wraps every medium batteries to move with ideal level evenly, rise thereby store can integral efficiency of the system and effectiveness, conduce to BBU module the system can last more and moving reliably. The BMS small controller that uses in BBU is MAX32625. BMS small controller is in charge of two important processes. Refer to a graph 1.

Graph 1. The BMS small controller that receives BMSIC(ADBMS6948) repeatedly (MAX32625) .

1. Correspond with BMSIC(ADBMS6948) , get temperature of batteries voltage, batteries, owe pressure, be pressed too and the telemetering data of level of electric current of integral batteries caboodle.

2. All telemetering data that through I2C communication will collect from parts of an apparatus is delivered advocate small controller.

BMS small controller corresponds through SPI agreement and ADBMS6948. Through sending proper command code, BMS small controller allows this to parts of an apparatus collects telemetering data and execute an operation at the same time. Refer to a graph 2. All data that collect from BMSIC will be sent by BMSMCU and handle.

Graph 2.BMS small controller sends the process of command and data of memory BMS chip.

Another of BMS small controller main task is the data that will collect is sent advocate small controller, use at charging to be controlled with discharge algorithm and fan rotate speed. This is to pass as small as BMS controller to undertake I2C agreement corresponds, next by advocate small controller reads those who take register to finish. If the register map of BMS small controller expresses 1 to show.

Express map of register of 1.BMS small controller

Ask an attention, at present register of all BMS small controller is read-only register. Compose builds date and serial number to be collected only, store next in advocate in the exterior EEPROM of small controller.

Batteries charges technology

Constant voltage (CV) and constant current (CC) is batteries charges to differ two kinds when use in the system charge technology, can optimize charge the process prolongs battery life.

CV charges

CV charges is one kind is charging initiative phase applies those who increase fixed tension to charge to batteries caboodle method. Charge process in the begining, BBU module job is charging mode, maintain the stable tension level of 44V, charging current begins from 5A, as the addition of batteries SOC reduce gradually. This kind of method is particularly effective to preventing overcharge, because voltage keeps constant, the safe voltage that won’t exceed batteries is restricted to be worth. Batteries caboodle voltage achieves 37V to come 40V or after defining threshold value beforehand, charger may transform other charge level, reduce charging current 0.5A from 5A for example.

CC charges

CC charges is to batteries caboodle terminal brings to bear on consistent charging current. In this phase, charging current maintains in 5A changeless, and batteries voltage undertakes as what batteries charges and lift gradually. This method to initiative charge the batteries caboodle with inferior level charges quickly particularly useful. It ensures electric current flows into batteries caboodle with controlled means, till reach certain tension level. Batteries caboodle voltage is achieved after booking a dot, charge the process can transform other phases, for example will constant electric current reduces 2A from 5A, perhaps enter constant voltage phase.

In BBU module batteries caboodle charges in mode, CV and CC charge the method often is united in wedlock use, charge ideally in order to obtain curve. Help of phase of early days CC transmits energy to batteries quickly, and phase of later period CV avoids overcharge through restricting voltage. Technology of this kind of combination can come true efficient charge, prolong battery life, hold the security that batteries includes and property. Carry out CV and CC charger correctly to make charge to BBU module the operation is crucial.

Batteries detects method

Batteries detects a crucial aspect that the method is batteries management system. This technology aims the tension that essence of life follows to decide every batteries in batteries bag and condition. Batteries detects the method is used detect complexly circuit and measure algorithm, the real time data that lets a system can collect the voltage that concerns every batteries, temperature and integral health condition, use these information to make next about charge, discharge and the advisability that operate evenly are decision-making, optimize the property that batteries includes, security and service life thereby. Effective batteries detects contemporary to maintaining store can integral efficiency of the system and dependability are crucial.

ADBMS6948 has 11 ADC, use technically at detecting the input of 11 batteries that need branch that batteries wraps. Batteries caboodle uses 11 series connection and 6 shunt-wound configuration, join C0 cites a base to C10, namely the ADC of BMS. The input limits of ADC is – 2.5V comes + 5.5V, sampling frequency is 4MHz about, every 1ms produces 16 results, LSB is 150 μ V. Additionally 11 ADC use S technically to bring a foot to measure 11 inputs that need branch at the same time, input limits comes for 0V 5.5V, sampling frequency is 4MHz about, every 8ms produces 13 results, LSB is 1.6mV. These S-ADC realize redundant batteries voltage to measure at the measurement technique of C-ADC through complete independence.

Passivity balances an operation

Passive balance is the commonly used technology in batteries system government, it uses passive cell (especially resistor) the compositive MOSFET that goes up in every batteries with paralell connection will achieve batteries balance. These compositive component assume voltage release implement or energy dissipation implement action, the batteries that is helpful for letting show taller voltage or energy state with the energy with controlled means redundant dissipation, make the voltage potential between batteries or energy condition are coordinated gradually consistent, be in thereby longer voltage and energy balance are promoted inside time.

If batteries wraps medium batteries to become lopsided, BMS must reach an equilibrium through letting the batteries with taller voltage discharge. The S-ADC on ADBMS6948 brings a foot to be able to be used at undertaking discharging to single cell. S-ADC brings a foot to go up inside the MOSFET of buy can be used at undertaking discharging to batteries. Every S-ADC brings a foot to be able to use PWM alone or successive control. Through configuring PWMA, PWMB and CFGB register, still can be in batteries of the balance when dormancy job mode in BMS small controller.

The batteries of use coulomb tally charges

The main effect of coulomb tally is accurate measure flow into the charge that pours out of batteries or circuit to measure (it is an unit with coulomb) . Measure through this kind, can control batteries to caboodle charges and discharge better, lengthen batteries to pile life thereby, improve efficiency, and monitor a capacity well and truly.

ADBMS6948 is compositive coulomb tally, because this can be monitored,charge the charge volume of batteries of process midstream classics. Coulomb tally also calls sensor of compositive electric current or charge monitor, the charge gross that be used at measuring to flow into or pours out of batteries (it is an unit with coulomb) . When use coulomb tally undertakes batteries charges, tally can monitor the charge volume that carries battery. This is the electric current that spreads classics cell through measuring is opposite his time integral is finished with computational total n. Accordingly, estimate the SOC of batteries and carry out charge algorithm can be optimized charge process.

The main operation of ADBMS6948 coulomb tally is involved will flow into the electric current that pours out of batteries caboodle integral to time, with the total charge that computation transmits. Its job principle is as follows: