CN202309118U

CN202309118U - Transformer scan chain type storage battery equalizing circuit

Info

Publication number: CN202309118U
Application number: CN2011203771741U
Authority: CN
Inventors: 张一�; 李思贤
Original assignee: SHANGHAI LIYAO ENERGY TECHNOLOGY Co Ltd
Current assignee: SHANGHAI LIYAO ENERGY TECHNOLOGY Co Ltd
Priority date: 2011-10-08
Filing date: 2011-10-08
Publication date: 2012-07-04
Anticipated expiration: 2021-10-08

Abstract

The utility model discloses a storage battery equalizing circuit comprising a plurality of single batteries which are connected in series and an external control circuit; wherein the each single battery is connected with an equalizing unit; the equalizing unit consists of an MOSFET (Metal-Oxide -Semiconductor Field Effect Transistor) which is connected in series between a positive electrode and a negative electrode of the single battery and a transformer winding; and the transformer winding in the each equalizing unit is from the same one shared multi-tap transformer. According to the transformer scan chain type storage battery equalizing circuit of the utility model, when the MOSFET is turned on, the single battery in the equalizing unit in which the MOSFET is arranged discharges to the corresponding transformer winding; and when the MOSFET is turned off, the transformer windings in the other equalizing units except for the equalizing unit in which the MOSFET is arranged charge the corresponding singe batteries, thus real high-efficiency and safe dynamic active equalizing charge and discharge of the battery can be achieved, thereby furthest protecting the battery, and giving full play to energy of the battery.

Description

Transformer scanning chain type batteries equalizing circuit

Technical field

The utility model belongs to the battery protection system field of storage battery, relates to a kind of transformer scanning chain type batteries equalizing circuit.

Background technology

Storage battery is as energy storage medium; The all trades and professions that have been widely used in society; Particularly in recent years in industries such as communication power supply, ups power, various power car, solar power generation, wind power generation, national intelligent grid; In the system as power or power supply energy storage, ferric phosphate lithium cell has been regarded as one of assembly of most critical.Battery system is to charging, discharge with the battery pack of series system work; After each charging, discharge; The characteristic of each cell all can be different in the battery pack; Like terminal voltage, internal resistance, degree of aging, residual capacity (SOC), battery health degree (SOH) or the like, and can As time goes on further aggravate the otherness between the cell.How guaranteeing that battery carries out the balanced control of battery pack dynamic active rapidly and efficiently in charging, discharge process, is to guarantee fail safe, the reliability of ferric phosphate lithium cell and a key technology giving full play to its chemical usefulness.

Along with the use of ferric phosphate lithium cell more and more widely, the apparatus and method of in recent years series connection ferric phosphate lithium cell group being charged, discharge have obtained continuous improvement, with attempt to the protection of the battery pack that is cascaded and equilibrium can be quick more, efficiently.In the traditional passive equalization methods of ferric phosphate lithium cell; It all is the discharge matrixing network of utilizing semiconductor switch device and power resistor to constitute; These matrixes are applied to each cell two ends, and the higher cell of terminal voltage discharges in right amount during to charging, and the voltage of each cell in the battery pack is raise so that identical speed is consistent as far as possible; While is sufficient, reaches the purpose of the passive equilibrium of series-connected cell; Just can reach balanced purpose because the power resistor that adopts will discharge to cell, the caloric value of resistance is big, and is therefore lower to the capacity usage ratio of battery pack front end charger, and bigger resistance generating thermal losses is arranged.

In traditional battery power discharge method; When wherein some battery reach the smallest end voltage that needs protection; Then whole battery group will be forced and stop discharge; But during this time, possibly also have a lot of energy remaining not to be released out in other some battery in good condition, so this will greatly influence the energy utilization rate of battery pack.

In traditional ferric phosphate lithium cell group charging method of seeing at present, be that the total voltage of the battery pack that is cascaded is gathered, do not monitor the terminal voltage of each cell; Though this way is simple; But because in use the electric weight of each cell is also inhomogeneous; If recycle down for a long time, it is bigger that the otherness of electric weight will become, so the less cell of electric weight will produce overdischarge; Make its life-span that recycles reduce greatly, therefore will influence the use of battery pack.Above-described charging method is set a battery power discharge final voltage often, when the total voltage that collects battery pack is lower than this set point, will stop the discharge of battery pack.Because final voltage can not reflect the true terminal voltage of all cells in the battery pack; Therefore when stopping discharge; The phenomenon of overdischarge may appear in some cell; Some cell possibly also have a lot of remaining electric weight not use, and the utilization rate of the energy content of battery will reduce greatly.

In traditional ferric phosphate lithium cell group charging method of seeing at present, all be that terminal voltage with reference to battery is as basis for estimation, when the terminal voltage of battery reaches certain numerical value; Just force to stop discharge, but under different actual environments for use, like ambient temperature when higher; Possibly also have a lot of remaining electric weight not discharge in the battery; And when ambient temperature was low, the phenomenon of battery over-discharge will appear, therefore can cause damage to battery.

Traditional ferric phosphate lithium cell is dynamically initiatively in the equalization methods, all is to utilize the voltage of all cells that are cascaded finally to reach consistent with the balanced operation termination condition.Be coarse like this.In fact the actual storage electric weight of battery also will receive the temperature of battery itself, the influence that accumulative total discharges and recharges the factors such as chemical characteristic of number of times, degree of aging, health degree, battery itself.Under different temperature, charge and discharge cycles number of times, the energy that can store and discharge when the ferric phosphate lithium cell group is full of electricity is inequality, and the terminal voltage of battery also is inequality when being full of electricity.As under low temperature environment, the energy that can store in the battery pack is less, and the terminal voltage when being full of electricity is higher, or the like.Just to need charging, electric discharge device under different environment, can maximum storable electric weight in the battery be full of, and can the electric weight that store in the battery pack all be discharged the supply external loading to greatest extent to utilizing the electric weight of storing in the battery pack.What deserves to be mentioned is, because each cell manufacturing process error or the like in the ferric phosphate lithium cell group, when serial connection charge; There is certain difference in its electric weight; And this species diversity can be in use slowly increase gradually, this will influence the operate as normal of whole battery group, therefore; This just needs charging, electric discharge device can eliminate this species diversity, makes battery pack in charging, discharge process, remain equilibrium state.

The utility model content

The purpose of the utility model provide a kind of compared with prior art more science, more reliably, more can utilize the equalizing circuit of ferric phosphate lithium cell group energy fully, to overcome deficiency of the prior art.

It is a kind of novel based on the dynamic electric weight of each cell and the series battery equalizing charge of voltage differences compensation, the circuit of discharge that the utility model provides, and specifically adopts following technical scheme:

A kind of batteries equalizing circuit comprises:

Batteries comprises the cell of a plurality of series connection;

Balance module comprises a plurality of balanced units identical with said cell number, all is connected with an independently balanced unit on each cell; Said balanced unit is made up of MOSFET between the both positive and negative polarity that is connected on cell and Transformer Winding; And the Transformer Winding in each balanced unit all comes from the different windings of same multi winding transformer; And

External control circuit is used to control the conducting of said MOSFET;

When said MOSFET conducting, the cell in this MOSFET place balanced unit is to its corresponding Transformer Winding discharge; When said MOSFET broke off, the Transformer Winding in other balanced units outside this MOSFET place balanced unit was given its corresponding cell charging.

As to the improving and replenishing of technique scheme, the utility model is further taked the following technical measures or the combination in any of these technical measures:

Said MOSFET is P-MOSFET; The S utmost point (source electrode) of said P-MOSFET connects the positive pole of cell; Its D utmost point (drain electrode) connects the end of the same name of Transformer Winding, and its G utmost point (grid) is connected with said external control circuit as control end, feeds control signal by external circuit and makes its ON/OFF.

Said MOSFET is N-MOSFET; The D utmost point (drain electrode) of said N-MOSFET connects the positive pole of cell; Its S utmost point (source electrode) connects the end of the same name of Transformer Winding, and its G utmost point (grid) is connected with said external control circuit as control end, feeds control signal by external circuit and makes its ON/OFF.

The number of turn of the Transformer Winding in said each balanced unit is identical.

Said multi winding transformer is many tapped transformers.

Said cell is a ferric phosphate lithium cell.

The above-mentioned equalizing circuit that the utility model provided; Be as basis for estimation, in the battery charging process, with the dynamic electric weight of each cell and voltage when finding between the cell that electric weight is with voltage differences greatly the time; Just electric weight and the higher cell of voltage are discharged in right amount; And transfer to an electric weight of releasing in other the cell, for other behindhand battery charges, be implemented in the dynamic equalization in the charging process; Equally in the process that batteries connection load is discharged; The cell that electric weight and voltage are high shifts the electric weight that has more to electric weight and the less cell of voltage through discharge circuit and charging circuit; Be implemented in the dynamic equalization in the discharge process; Finally reach real efficient, safe dynamic active equalizing charge and the discharge of battery pack, can protect battery to greatest extent, give full play to the energy of battery pack.

Description of drawings

Fig. 1 is the equalizing circuit syndeton sketch map of n cell series connection in the utility model.

Fig. 2 is the balanced unit sketch map that connects on cell in the utility model.

Fig. 3 is the equalizing circuit syndeton sketch map of n cell series connection of another kind of execution mode in the utility model.

Fig. 4 is that cell CELL-1 shifts the equalizing circuit work schedule sketch map to CELL-2～CELL-n to energy in the utility model.

Embodiment

Further set forth the utility model below in conjunction with specific embodiment, should be understood that these embodiment only be used to the utility model is described and be not used in the restriction the utility model protection range.

Fig. 1 is the equalizing circuit syndeton sketch map of n cell series connection in the utility model, all establishes a balanced unit independently on each cell, shared n P-MOSFET, a n transformer tapping winding.Seeing also Fig. 1 and 2, is example with first cell CELL-1 wherein: the balanced unit that is connected with this cell is made up of with Transformer Winding 11 P-MOSFET between the both positive and negative polarity that is connected on cell CELL-1 21; The S utmost point (source electrode) 3 of P-MOSFET 21 connects the positive pole of cell CELL-1; Its D utmost point (drain electrode) 2 connects the end of the same name of Transformer Winding 11; Its G utmost point (grid) 1 is connected with said external control circuit as control end, feeds control signal by external circuit and makes its ON/OFF.The balanced unit that is connected on each cell is all identical, and just the Transformer Winding in each balanced unit all comes from the different windings on public many taps high-frequency power transformer 30.

Fig. 3 is the equalizing circuit syndeton sketch map of n cell series connection of the another kind of execution mode of the utility model; Fig. 3 and Fig. 1 similar; Difference only is: the MOSFET among Fig. 3 adopts N-MOSFET, and the D utmost point (drain electrode) of N-MOSFET connects the positive pole of cell, the end of the same name of its S utmost point (source electrode) connection Transformer Winding; Its G utmost point (grid) is connected with said external control circuit as control end, feeds control signal by external circuit and makes its ON/OFF.

Fig. 4 is the operation principle sketch map of the utility model.In use; Use the charging current of batteries or batteries discharging current and time are to external world calculated the dynamic electric weight size in wherein cell charging, the discharge process; When the dynamic electric weight between the cell and terminal voltage difference during greater than set point; The dynamic active of just carrying out electric weight and voltage is balanced, the MOSFET conducting that will link to each other with the higher cell of electric weight through external control circuit.A certain side winding by the positive pole of the cell of gating and P-MOSFET, high-frequency power transformer constitutes series loop; When corresponding M OSFET conducting; The Transformer Winding that is connected is recharged, and electric current rises, the beginning storage power; Because the winding of transformer reaches and is the positive incentive pattern with being connected of power device, corresponding battery CELL is discharged; Under the undersaturated situation of transformer, the Joule energy P that Transformer Winding stores is: and P=I*I*L/2 (maximum current that rises to for the Transformer Winding inductance of I wherein, unit is an ampere; L is the inductance value of Transformer Winding inductance, and unit is Henry).After Transformer Winding is recharged; The MOSFET that opens before need at once closing, that time that Transformer Winding is recharged is owing to the MOSFET that connects on other each cell, Transformer Winding etc. have also constituted a series loop; Because there is parasitic reverse body diode power MOSFET inside; The connection framework that adds entire circuit is the positive incentive structure, so the parasitic reverse body diode of the MOSFET that the winding of connecting on other the cell will be through series connection constitutes charge circuit, and winding begins to be recharged; Electric current rises, and corresponding cell is recharged; Finally, the energy of battery discharge is transferred to other battery, has accomplished dynamic equalization.And in whole use, control dynamic charge value of cell and magnitude of voltage all the time and when charging, be not more than its maximum rated value that allows, when discharge, be not less than its minimum rated value that allows.

According to said process, just accomplished the process that some cells can discharge separately or charge, no matter batteries is recharged; Or batteries outwards the discharge in; Can realize the independent charging and discharging of some cells, the cell that can guarantee to be cascaded can voltage under any state near or capacity approaching, protection can not produce the serious overvoltage of indivedual cells in charging process; Also guarantee in discharge process simultaneously; It is seriously under-voltage not have indivedual cells, to protect battery to greatest extent, gives full play to the energy of battery pack.

Foregoing description of the utility model and application are illustrative, are not to want the scope of the utility model is limited in the above-described embodiments.Here the distortion of the embodiment that is disclosed and change are possible, and the replacement of embodiment is known with the various parts of equivalence for those those of ordinary skill in the art.Those skilled in the art are noted that under the situation of spirit that does not break away from the utility model or substantive characteristics the utility model can be realized with other forms.Under the situation that does not break away from the utility model scope and spirit, can carry out other distortion and change here to the embodiment that is disclosed.

Claims

1. batteries equalizing circuit comprises:

Batteries comprises the cell of a plurality of series connection;

External control circuit is used to control the conducting of said MOSFET;

2. batteries equalizing circuit as claimed in claim 1; It is characterized in that said MOSFET is P-MOSFET, the S utmost point of said P-MOSFET connects the positive pole of cell; Its D utmost point connects the end of the same name of Transformer Winding, and its G utmost point is connected with said external control circuit as control end.

3. batteries equalizing circuit as claimed in claim 1; It is characterized in that said MOSFET is N-MOSFET, the D utmost point of said N-MOSFET connects the positive pole of cell; Its S utmost point connects the end of the same name of Transformer Winding, and its G utmost point is connected with said external control circuit as control end.

4. batteries equalizing circuit as claimed in claim 1 is characterized in that, the number of turn of the Transformer Winding in said each balanced unit is identical.

5. like the arbitrary described batteries equalizing circuit of claim 1-4, it is characterized in that said multi winding transformer is many tapped transformers.