With the lithium battery protection circuit device of freewheeling circuitTechnical field
The invention belongs to lithium battery protection circuit field, relate to one have overcharge, cross put, overcurrent, short-circuit protection function, particularly there is after protection the single lithium battery protective circuit of charge and discharge afterflow function.
Background technology
Existing single lithium battery protective circuit have monomer lithium cell (lithium cell---do not have the lithium of installed protection device or lithium-ions battery) overcharge, cross put, overcurrent, short-circuit protection function; the single lithium battery (lithium battery---lithium cell installs the monomer lithium after baffle or lithium-ions battery additional) configured by itself and monomer lithium cell in use can not overcharging or crossing and put and damage because of lithium cell; when also ensure that lithium battery overcurrent and short-circuit conditions occur, lithium cell can not be made overheated and on fire.
As shown in Figure 1, the lithium battery protection circuit of prior art is of a great variety, namely the lithium battery protection circuit built by protection monitoring chip IC and peripheral original paper is had, there is again highly integrated monolithic li-ion cell protection integrated circuit, but lithium battery protection circuit device and the effect of drawing link outward all can be summarized as: by just, negative input end B+, B-is just connecting lithium cell respectively, negative pole, the voltage and current of lithium cell is monitored, external charger just, negative output terminal or load are just, negative input end and protective circuit unit are just, negative output terminal P+, P-connects, by protective circuit device to lithium cell charging or lithium cell to load discharge.Monitoring and Controlling circuit and electronic switch is all provided with in protective circuit device; when the threshold values state monitoring several inner setting occurs; the filling of control circuit, put control end and transfer low level to by high level and electronic switch in control protection electric circuit cuts off external circuit to the charge and discharge passage of lithium cell; protection lithium cell can not because of overcharge; overdischarge, the situation such as overcurrent and short circuit and damaging.
Charging control end OC in foregoing circuit also can as the control end of other circuit.
Function and several mode of operation of existing protective circuit device all can be summarized as described below:
Lithium battery normal mode of operation: if lithium cell voltage is lower than over-charge protective threshold voltage; higher than Cross prevention threshold voltage; the electric current of process is less than overcurrent protection threshold values; the control end OC that now charges is in high level; electronic switch in protective circuit device is in closed conducting state, lithium cell by the charge or discharge between protective circuit and external circuit all by free conversion.
Over-charge protective pattern: in charging process; when lithium cell voltage is higher than over-charge protective threshold voltage; the charging control end OC of protective circuit device overturns as low level; electronic switch simultaneously in protective circuit open circuit; cut off external circuit to the charge tunnel of lithium cell, and the charging direction in edge between output P+, P-keeping protective circuit is that high resistant is equivalent to off-state.
Overdischarge stream and short circuit protection mode: under lithium battery operating state; when discharging current be equal to or higher than protective circuit setting threshold values; or there is short circuit in discharge loop; when causing abnormal large electric current; electronic switch in protective circuit open circuit; cut off the discharge channel of lithium cell, lithium cell stops electric discharge.Until load disconnects, protective circuit just returns to normal mode state.
Only have the defencive function to lithium cell by the above existing protective circuit device, the single lithium battery configured by itself and monomer lithium cell is also only suitable for single-unit and uses.If its direct multi-section serial is used, because each single lithium battery can not be completely the same in performance index, capacity in use between each single lithium battery, self discharge, life time decay inconsistent, accumulate over a long period, each batteries there will be increasing voltage deviation and deposits electricity deviation in real time, in series battery, any one cell fills, discharge prevention all can make filling of whole series battery, put back to road to cut off, so that filling, other cells in battery pack can be made during electric discharge to be not fully filled more and more or cannot not put completely, each single lithium battery capacity potential more and more can not give full play to.And the lithium battery group being separately configured with balanced charge and discharge management devices all needs internode tap just can carry out monitoring and carry out balanced charge and discharge management.This just makes production cost and development cost improve, and especially relative to the product being configured with lithium battery group, is that technical staff is to the maintenance of product or common user is very difficult to the maintenance of this product.
Summary of the invention
The object of the invention is:
There is provided one not only to have to overcharge, cross put, overcurrent, short-circuit protection function, and still can fill, put the single lithium battery protective circuit device of afterflow in guard mode.Monomer lithium cell positive pole is connected with the positive input terminal of the lithium battery protection circuit device of described band freewheeling circuit; monomer lithium cell negative pole is connected with the negative input end of the lithium battery protection circuit device of described band freewheeling circuit, thus forms the single lithium battery of the lithium battery protection circuit device being furnished with band freewheeling circuit.The single lithium battery of such formation both can be used alone; more piece single lithium battery directly can be connected again and use in groups; lithium battery group particularly directly after series connection not only each single lithium battery have commonly to overcharge, cross put, overcurrent and short-circuit protection function; but also do not need outer draw internode tap and monitor; do not need separately to establish balanced management system; inherently automatically form battery pack balancing system after its series connection in groups, thus possess upper balanced, the lower balanced function of electric discharge of charging.Cell is used in groups greatly simple, convenient, production cost and development cost are reduced, especially relative to the product of configuration lithium battery group, be that technical staff or the replacing of common user to the maintenance of this product and single lithium battery are all very simple and convenient.
For achieving the above object, the present invention adopts following technical scheme:
As shown in Fig. 2, Fig. 7, a kind of lithium battery protection circuit device with freewheeling circuit, is characterized in that, this device by common had put, the single lithium battery protective circuit of overcurrent, short-circuit protection function and monomer freewheeling circuit form jointly, externally filling of existing single lithium battery protective circuit, to put between positive output end P+ and negative output terminal P-and connect one controlled by just, the freewheeling circuit of reverse current, described monomer freewheeling circuit is in not on-state when the non-protectiveness of single lithium battery protective circuit is cut off, and once single lithium battery protective circuit is in and overcharges, Cross prevention state and filling lithium cell, when discharge loop cuts off, monomer freewheeling circuit is conducting immediately just, still provided a current channel between positive output end P+ and negative output terminal P-, to make between positive output end P+ and negative output terminal P-still by just, reverse current.Like this when two or more be configured with the present invention protect the lithium battery of 0 road device to be connected into battery pack time; the protective circuit device of any joint single lithium battery the charge and discharge of this section lithium cell to limit protectiveness cut-out to the filling of this section lithium cell, put back to road time; there is the freewheeling circuit conducting immediately of this section in capital; continue the charge and discharge loop of whole series battery, make filling or discharge and still can proceeding of other single lithium battery of battery pack.
Each single lithium battery in series battery is when charging, and all this section can be full of this section protection cut-out, the afterflow of this section freewheeling circuit cell conduction, until each single lithium battery is all full of, thus it is upper balanced to reach charging; And when discharging; each cell can distinguish discharge prevention, this section freewheeling circuit conducting afterflow, until final section discharge prevention in series battery; as long as the power input voltage range lower limit of electricity consumption load request is enough wide, the capacity potential of series battery just can give full play of.
Owing to filling, put protectiveness to cut off, bypass circuit conducting afterflow all self completes in each single lithium battery, the charge and discharge that the cut-out in monomer lithium cell loop does not affect whole battery pack proceeds, even if so the cell capacity of composition series battery differs greatly, each single lithium battery in battery pack also can give full play to self capacity potential, the parameter of certain cell is not good can not give full play to generation restrictive function to the capacity potential of other batteries, this just makes to match selection to the capacity of each cell during composition series battery need not be so strict, be conducive to reducing costs.
The course of work of the present invention is described in detail in detail below.
As shown in Figure 3, a kind of lithium battery protection circuit device with freewheeling circuit, this device comprise common have overcharge, cross and put, overcurrent, the monomer protective circuit of short-circuit protection function, it is characterized in that also comprising monomer freewheeling circuit, monomer freewheeling circuit is by P channel mosfet pipe, diode, form with current-limiting circuit, wherein the source electrode of P channel mosfet pipe is connected with the positive output end of the negative pole of diode with monomer protective circuit, the grid of P channel mosfet pipe is connected with the charging control end of monomer protective circuit, the drain electrode of P channel mosfet pipe is connected with one end of current-limiting circuit, the other end of current-limiting circuit is connected with the negative output terminal of the positive pole of diode with monomer protective circuit.
The lithium battery protection circuit device of described band freewheeling circuit, when external charger just, negative pole respectively with the device positive output end P+ of lithium battery protection circuit, negative output terminal P-is connected through monomer protective circuit when charging normal monomer lithium cell CELL, the charging control end OC of monomer protective circuit is high level, this level is added to the grid of P channel mosfet pipe Q, P channel mosfet pipe Q is in off-state, current-limiting circuit no current passes through, diode D is in reversal connection, also no current passes through, external charger is charged normal monomer lithium cell CELL by monomer protective circuit.Along with the carrying out of charging, the voltage of monomer lithium cell CELL rises gradually, when be full of reach monomer protective circuit built-in upscale protection threshold voltage time, charging control end OC upset is low level, monomer protective circuit cuts off external circuit to the charge tunnel of lithium cell CELL, protection lithium cell CELL can not overcharge, and keep monomer protective circuit to be equivalent to off-state relative between positive output end P+ and negative output terminal P-in high resistant, now the low level of charging control end OC is also added to the grid of P channel mosfet pipe Q, make P channel mosfet pipe Q conducting, external charger will by P channel mosfet pipe Q, current-limiting circuit continues to flow through electric current, like this at output P+, a current channel has been had again between P-.
As shown in Figure 3; monomer lithium cell positive pole is connected with the positive input terminal of the lithium battery protection circuit device of described band freewheeling circuit; monomer lithium cell negative pole is connected with the negative input end of the lithium battery protection circuit device of described band freewheeling circuit, thus forms the single lithium battery of the lithium battery protection circuit device being furnished with band freewheeling circuit.
As shown in Figure 7, when by plural be equipped with the single lithium battery of protective device of the present invention connect use in groups time, external charger just, negative pole respectively with the positive output end BAT+ of battery pack, the negative output terminal BAT-of battery pack connects, if when now certain joint single lithium battery has been in and has been full of guard mode, but the still underfill of the battery outside it, so the freewheeling circuit of this joint provides charging current passage still can to whole charge circuit, the battery making other connect can also continue charging, until each is full of all respectively, protect respectively, afterflow respectively, until be all full of, thus it is balanced in the charging achieving series battery.
When regular picture; be connected with the positive output end BAT+ of battery pack, the negative output terminal BAT-of battery pack respectively at the positive and negative input of external loading; each lithium cell through this section monomer protective circuit to load regular picture; the charging control end OC of each monomer protective circuit is high level; this level is added to the grid of P channel mosfet pipe Q in respective freewheeling circuit; P channel mosfet pipe Q is in off-state; current-limiting circuit no current passes through; diode D is in reversal connection; also no current passes through, and electric discharge is normally carried out.Along with the carrying out of electric discharge; each lithium cell CELL two ends reduce gradually; when the lithium cell voltage drop of certain joint is below Cross prevention threshold voltage; this joint monomer protective circuit cuts off the discharge channel of this section lithium cell to load; stop electric discharge, monomer protective circuit is relative to being that high resistant is equivalent to off-state along course of discharge between its output P+, P-.If now the non-discharge prevention of other lithium battery still can be powered; the voltage of so overall discharge loop can apply positive voltage to the negative output terminal P-of this joint lithium battery; negative voltage is applied to positive output end P+; the now diode D forward conduction of this joint monomer freewheeling circuit; there is provided passage still can to whole discharge loop; flow through discharging current, make other unprotected battery in series battery continue electric discharge.The cell of each series connection can distinguish discharge off like this, cuts off respectively, respectively freewheeling circuit conducting, until final section discharge prevention just terminates electric discharge in series battery, so just makes the capacity potential of whole battery pack all can discharge.
Fig. 1 is the schematic diagram of existing lithium cell protecting device
Fig. 2 is schematic block diagram of the present invention
Fig. 3 is structural representation of the present invention
Fig. 4 is the structural representation of embodiment of the present invention 1
Fig. 5 is the structural representation of embodiment of the present invention 2
Fig. 6 is the structural representation of embodiment of the present invention 3
Fig. 7 is the schematic diagram that apparatus of the present invention are connected when using in groups
Specific embodiment 1
As shown in Figure 4, the lithium battery protection circuit of band freewheeling circuit, is jointly made up of cell core protective circuit and monomer freewheeling circuit, and is made on one piece of circuit board.Described monomer freewheeling circuit is made up of P channel mosfet pipe Q, current-limiting circuit, diode D; current-limiting circuit is resistance R; the positive output end P+ of single lithium battery protective circuit is connected with the source electrode of P channel mosfet pipe Q and the negative pole of diode D; the node OC of cell core protective circuit is connected with the grid of P channel mosfet pipe Q; the drain electrode of P channel mosfet pipe Q is connected with one end of resistance R, and the other end of resistance R is connected with the negative output terminal P-of the positive pole of diode D with monomer lithium cell protective circuit.
When charging normal, monomer protective circuit is in non-guard mode, external charging loop just, negative voltage is not added to positive output end P+, negative output terminal P-, after-applied at positive input terminal B+ through monomer protective circuit, on negative input end B-, align, the negative pole respectively monomer lithium cell CELL of cross-over connection on it charges normal, the control end OC that now charges is high level, this level is added to the grid of P channel mosfet pipe Q, P channel mosfet pipe Q is in off-state, the current-limiting circuit no current be made up of resistance R passes through, diode D is in reversal connection, also no current passes through, freewheeling circuit unit does not have electric current to pass through.
Along with the carrying out of charging; the voltage of monomer lithium cell CELL rises gradually; when be full of reach monomer lithium cell protective circuit built-in upscale protection threshold voltage time; single lithium battery protective circuit cuts off the charge circuit to monomer lithium cell CELL; the charging control end OC of protective circuit overturns as low level simultaneously; this low level is added to the grid of P channel mosfet pipe Q; make its conducting, the logical source electrode along positive output end P+ → channel mosfet pipe Q, drain electrode → resistance R → negative output terminal P-are continued to flow through electric current by external power source.Although be in off-state from the charge tunnel of cell core protective circuit like this; but freewheeling circuit provides again an electric current is flowed to negative output terminal P-current channel by positive output end P+ between positive output end P+ and negative output terminal P-, as long as the value arranging the resistance R of different current-limiting circuits just can obtain different freewheel current values.
As shown in Figure 7, when by plural be equipped with the single lithium battery of protective device of the present invention connect use in groups time, external charger just, negative pole respectively with the positive output end BAT+ of battery pack, the negative output terminal BAT-of battery pack connects, if when now certain joint single lithium battery has been in and has been full of guard mode, but the still underfill of the battery outside it, so the freewheeling circuit of this joint provides charging current passage still can to whole charge circuit, the battery making other connect can also continue charging, until each is full of all respectively, protect respectively, afterflow respectively, until be all full of, thus it is balanced in the charging achieving series battery.
When regular picture; be connected with the positive output end BAT+ of battery pack, the negative output terminal BAT-of battery pack respectively at the positive and negative input of external loading; each lithium cell through this section monomer protective circuit to load regular picture; the charging control end OC of each monomer protective circuit is high level; this level is added to the grid of P channel mosfet pipe Q in respective freewheeling circuit; P channel mosfet pipe Q is in off-state; current-limiting circuit no current passes through; diode D is in reversal connection; also no current passes through, and electric discharge is normally carried out.Along with the carrying out of electric discharge; each lithium cell CELL two ends reduce gradually; when the lithium cell voltage drop of certain joint is below Cross prevention threshold voltage; this joint monomer protective circuit cuts off the discharge channel of this section lithium cell to load; stop electric discharge, monomer protective circuit is relative to being that high resistant is equivalent to off-state along course of discharge between its output P+, P-.If now the non-discharge prevention of other lithium battery still can be powered; the voltage of so overall discharge loop can apply positive voltage to the negative output terminal P-of this joint lithium battery; negative voltage is applied to positive output end P+; the now diode D forward conduction of this joint monomer freewheeling circuit; there is provided passage still can to whole discharge loop; flow through discharging current, make other unprotected battery in series battery continue electric discharge.The cell of each series connection can distinguish discharge off like this, cuts off respectively, respectively freewheeling circuit conducting, until final section discharge prevention just terminates electric discharge in series battery, so just makes the capacity potential of whole battery pack all can discharge.Due to the existence of afterflow passage, namely give full play to the capacitance potential of whole battery pack, reached again lower equilibrium.
Embodiment 2
As shown in Figure 5; shown in embodiment 1; it is characterized in that described current-limiting circuit forms jointly by resistance R with the LED of the resistance R0 that connected of resistance R parallel connection; the anode of LED of resistance Ro of having connected is connected with the drain electrode of one end of resistance R with P channel mosfet pipe Q, and the negative terminal of the LED of the resistance Ro that connected is connected with the negative output terminal P-of monomer protective circuit with the other end of resistance R.
Described in specific embodiment 1, when the Q conducting of P channel mosfet pipe, also have electric current to pass through in the series circuit that LED and resistance R0 form, LED is luminous, both afterflow effect can be produced as current-limiting circuit, the instruction that can be full of as single lithium battery again.
Embodiment 3
As shown in Figure 6; described in embodiment 1; it is characterized in that: described current-limiting circuit is composed in parallel by the LED of n (n is the integer of >=1) resistance Ro that connected; its anode is all connected with the drain electrode of P channel mosfet pipe, and negative terminal is all connected to the negative output terminal P-of monomer protective circuit unit.
Described in embodiment 1; when protective circuit is in the pipe Q conducting of charge protection state P channel mosfet; the LED of n the Ro that connected all flows through electric current, not only can produce afterflow effect as current-limiting circuit, can also use as lighting source.