| Waste batteries may be small, against Queshen | | | | miscarriage of justice charge for overcharge |
| big. However, due to pollution, waste batteries do | | | | protection, so need to set the delay time and |
| not like waste, air and water pollution, as could | | | | delay time can not be shorter than the duration |
| any sensory feel it has great hidden, so did not | | | | of the noise so as to avoid miscarriage of justice. |
| receive due attention. At present, China's Dell | | | | Overcharge protection delay time tvdet1 |
| gd761 battery production and consumption to | | | | calculated as follows:t vdet1 = (C3 × (Vdd - 0. |
| become a big country, and used batteries pollution | | | | 7)) / (0. 48 × 10 - 6) (1) |
| is an urgent need to address a major | | | | Where: Vdd for the protection of N1 Over-charge |
| environmental problem. According to | | | | detection voltage value. |
| environmental experts, in the recovery of waste | | | | Simple calculation of delay time: t = C3 / 0. 01 × |
| batteries per 1,000 grams of metal, of which | | | | 77 (ms) (2) |
| there are 82 grams of mercury, 88 grams | | | | Should the value of C3 capacity 0.22 F, then the |
| cadmium, can be said that disposal of waste | | | | delay value is: 0. 22 / 0. 01 × 77 = 1694 (ms) |
| batteries recycling is not only addressed the | | | | 1.2.2 over-discharge protection |
| sources of pollution, but also achieve the recycling | | | | In the case of excessive discharge, the |
| of resources. In developed countries the recycling | | | | electrolyte decomposition due to deterioration |
| of spent batteries and use very seriously. Many | | | | caused by the battery characteristics and result in |
| countries in Western Europe, not only in stores, | | | | reduced number of charge cycles. Over-discharge |
| but also directly on the street are equipped with a | | | | protection IC principle: In order to prevent |
| special battery recycling box, and used batteries | | | | excessive battery discharge status, assuming that |
| are 95% of the material can be recycled, | | | | lithium battery connected to the load, when the |
| particularly in high-value metal recovery. Such as | | | | lithium battery voltage is lower than the |
| the Foreign Secondary Lead industry developed | | | | over-discharge voltage detection point (assumed |
| rapidly, the current lead 55% of all production | | | | to be 2.3 V) will activate the over-discharge |
| comes from regenerated lead. The Secondary | | | | protection, so that power MOS FET transition |
| Lead Industry in dealing with the regeneration of | | | | from open-cut and the cut-off discharge, in order |
| waste lead-acid batteries account for a substantial | | | | to avoid battery over-discharge phenomenon, and |
| portion. 100 kg of waste lead-acid batteries can | | | | will keep the battery at low quiescent current |
| be recycled 50 to 60 kilograms of lead. Cadmium | | | | standby mode, at this time current is 0.1?A. When |
| batteries for the regeneration of waste | | | | the lithium battery connected to the charger, and |
| treatment technology abroad, have been more | | | | lithium Dell gd761 battery voltage is higher than at |
| mature to deal with 100 kilograms of cadmium | | | | this time of excessive discharge voltage, |
| battery scrap recycling about 20 kg of metal | | | | over-discharge protection be lifted. In addition, |
| cadmium, mercury batteries are mainly used for | | | | taking into account the charge and discharge pulse |
| the environmentally sound processing means to | | | | the case, over-discharge detection circuit with |
| prevent the pollution of the environment . | | | | delay time in order to avoid malfunction. |
| However, there are in this area of management | | | | 1.2.3 Over-current and short-circuit current |
| rather weak. | | | | protection |
| Note: Do not connect both ends of the battery, | | | | Because of unknown reasons (discharge or are |
| otherwise the battery will short-circuit, damaging | | | | negative by metal objects inadvertently) caused |
| the battery Lithium-ion Dell gd761 battery | | | | by over-current or short circuit, in order to |
| Protection Circuit Design A circuit design | | | | ensure safety, you must immediately cease its |
| 1.1 Circuit Overview | | | | discharge. Principles of over current protection IC, |
| Lithium-ion battery protection circuit includes | | | | when the discharge current is too large or short |
| over-charge protection, over current / short | | | | circuit conditions arise, the protection IC will be |
| circuit protection and over-discharge protection, | | | | activated off (short circuit) current protection, |
| the circuit is to ensure that such over-charge and | | | | over current detection at this time is to power |
| discharge status of the safety and to prevent the | | | | MOSFET's Rds (on) as a sensor for monitoring |
| characteristic deterioration. It is mainly protected | | | | the impedance the voltage drop in the case, if the |
| by the integrated circuit IC, chip resistors, chip | | | | ratio set by the overcurrent detection voltage is |
| capacitors, field effect transistor (MOSFET), and | | | | higher then the stop discharge, computing formula |
| some even thermistor (NTC), identify the | | | | is: |
| resistance (ID), fuse (FUSE) and other | | | | V_ = I × Rds (on) × 2 (V_ for the |
| accessories. The circuit shown in Figure 1. | | | | over-current detection voltage, I is discharge |
| Lithium-ion Battery Protection Circuit | | | | current) (3) assumes V_ = 0. 2V, Rds (on) = 25 |
| One integrated protection circuit protection circuit | | | | m?, while protecting current size of I = 4 A. |
| IC is used to detect the current voltage, current, | | | | Similarly, over-current detection delay time must |
| time and other parameters in order to control the | | | | also be provided to prevent current flow |
| FET switch state; field effect transistor (MOSFET) | | | | generated when there are unexpected |
| is under the protection of IC to control the loop | | | | malfunction. Usually after the election of |
| whether it might be open or closed ; chip resistors | | | | over-current if they can remove the over-current |
| used for current-limiting; Chip Capacitors role is to | | | | factors (such as immediately and load out) will |
| filter, adjust delay time; thermistor is used to | | | | resume its normal state, can then carry out the |
| detect the ambient temperature inside the cell | | | | normal charge-discharge action. 2 Conclusion |
| block; fuse to prevent the current flowing through | | | | Carrying out protection circuit design to a full Dell |
| the battery is too large, cut off the current loop. | | | | 312-038 battery charge state is the user's |
| 1.2 Circuit principle and parameter determination | | | | concern, taking into account the security problems |
| 1.2.1 The over-charging protection | | | | and therefore need to allow the voltage to reach |
| When the charger for lithium battery overcharge, | | | | cut-off state of charge. To simultaneously satisfy |
| the lithium batteries will be a result of | | | | these two conditions, there must be a high |
| temperature rise caused by increased internal | | | | precision detector, current detector precision of |
| pressure required to terminate the current charge | | | | 25 mV. Is also important to take into account the |
| state. At this point, integrated protection circuitry | | | | integrated protection circuit IC power |
| required to detect the battery voltage IC, when | | | | consumption, resistance to high voltage problems. |
| the arrival time 4.25V (assuming the battery | | | | Moreover, in order to power MOSFET's Rds (on) |
| charging voltage over the critical point at 4.25 V) | | | | in the charge current and discharge current when |
| that is activated over-charge protection, | | | | the effective application is required so that the |
| will-power MOS from the opening to cut off, then | | | | impedance as low as possible, at present the |
| cut-off charge. In addition, in order to prevent | | | | impedance is about 20 ~ 30 m?, the overcurrent |
| excessive because the noise generated by the | | | | detection voltage can be so low. |