Intelligent Li-ion Cell Management System (Li-ion cell charger with protection system)

Inteligent Li-ion cell management system circuit preset in one of my project

The Intelligent Li-ion cell management system is a circuit which has an efficient charging facility, short circuit protection and a deep discharge protection. That is this management system completely protect the cell and improve its performance and its life. Here in this blog I made the circuit by adding some extra protection features to the previous blog about the Li-ion charger. Here I add the features like output short circuit protection and a deep discharge battery shutdown features. This create this to be a intelligent battery system. The output short circuit protection keep the cell in a safe condition. Otherwise the short circuit produce an excess current drawn from the cell and it cause an increasing in temperature in the cell due to the power drop on the internal resistance of the Li-ion cell. This high temperature causes an internal short circuit and thus the Li-ion cell catch on fire. This make a large disaster. So this protection circuit protect us from this dangerous situation. The second protection is the deep discharge protection. This system disconnect the cell from the load when the cell reaches a critically low voltage which affect the cell life. If there is no protection against deep discharge the battery get damaged. So this intelligent system protect the cell from damage. For implementing these protection systems I use a small IC which name is DW01.  The circuit details given below. Also the circuit contain a Li-ion charger circuit based on the TP4056 IC which is explained in the previous blog.

Circuit Diagram

Intelligent Li-ion cell management system circuit diagram

The first part in the above circuit diagram is the Li-ion charger based on the TP4056 IC. The details about this part is explained in my previous Blog named "DIY Li-ion Cell Charger Using TP4056". The second part is the protection circuit. The controller IC which I used here is the DW01. It detect the low voltage and the short circuit conditions. Based on this detection it generate output signals at OC and OD pins in the IC. This signal is given to a mosfet IC 8205A. It contains two N channel mosfets. The signal from DW01 is switch ON and OFF this mosfets (connect two in series) and thus easily controls the output. So the output is OFF when there is a low voltage or a short circuit condition occurs.  Also the IC protect cell from over voltage charging. The mosfet IC contain reversely connected diodes in each mosfets. Thus the circuit capable of charging when the cell voltage is under the cutoff voltage. That is the diodes are used for charging the cell. The circuit cutoff output when the output is short circuited. The circuit is again switch ON only when the load (short circuit) is removed. This is the necessary circuit details. For more details visit the IC datasheets.

I use this circuit in many projects which I completed. The above image is from one of my project.

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Note: The mosfet is connected to the cell negative rail. So the cell ground and the circuit (output) ground are not same. Don't connect it together otherwise it don't protect from anything.