Background technology
Wind power generation is one of important composition realizing China's energy and the electric power strategy of sustainable development.Because wind power output power has very strong fluctuation, randomness, and there is certain error in forecasting wind speed, and the grid-connected meeting of large-scale wind power brings a series of technical barrier to the safe and stable operation of electric power system.Therefore, in order to more efficiently utilize regenerative resource, at wind energy resources than in more rich environment, general structure wind storage complementary system generates electricity, energy storage technology is adopted to regulate and control blower fan unit power output, make wind energy turbine set maximizing the benefits, to improve wind farm grid-connected serviceability, improve the continuity of system power supply, stability and reliability.
Existing power storage mode, mainly contains physics energy storage, Power Flow (as superconducting magnetic energy storage etc.) and battery energy storage three major types.Wherein, battery energy storage mainly includes storage battery, capacitor and fuel cell etc.But because the restriction in capacitance of storage and price etc. of ultracapacitor, fuel cell makes it not be suitable for extensive electric power storage occasion.Therefore, extensive electric power storage mainly adopts storage battery at present.Wherein, lead acid accumulator, lead-acid battery is the electric power storage technology of comparative maturity, though have cheap, security performance advantage relatively reliably, but still exist cycle life shorter, can not deep discharge, its capacity and electric discharge closely related, the shortcoming such as operation and maintenance cost is high of power, be difficult to the requirement meeting extensive electric power storage development.The technical threshold of sodium-sulphur battery is higher, the severe corrosive of its positive and negative electrode active material, harsh to the requirement of battery material, battery structure and service conditions, and there is severe compromise during short circuit; The charging and discharging state (SOC) of this battery can not accurately on-line measurement; Need additional heating equipment to maintain operating temperature, cause start-up time long, when can not adapt to that summer, wind-force generation assets was not good, need the startup requirement that energy-storage system intermittence is run.
Lithium ion battery obtains important breakthrough in fail safe, energy conversion efficiency and economy etc., and the condition of commercial application reaches its maturity, and is considered to one of Main way of following energy storage technology development.But, in order to adapt to the application demand of the large scale systems such as energy-accumulating power station, usually form battery pack after a large amount of cells being carried out connection in series-parallel, the positive and negative electrode material adopted due to each manufacturer, the quality of electrolyte and technique are different, its performance are understood some difference.Such as same model (standard cell of same encapsulation), the capacity of its battery has bigger difference (10% ~ 20%).Thus, how to make any one or more battery unit in battery pack carry out equalizing charge, realize controlling flexibly, euqalizing current is constant, to improve the consistency of battery pack, is the current problem needing solution badly.
Utility model content
The purpose of this utility model is to provide a kind of Li-ion batteries piles balanced management system, equalizing charge can be carried out to battery unit any one or more in battery pack by the mode of energy trasfer, euqalizing current is constant, control flexibly, effectively can improve the consistency of battery pack, meet the application demand of the large scale systems such as energy-accumulating power station.
In order to achieve the above object, a technical scheme of the present utility model is to provide a kind of Li-ion batteries piles balanced management system, and described Operation system setting has circuit of battery pack balancing, wherein comprises: balance controller, energy trasfer formula circuit; Described energy trasfer formula circuit, comprises further: multiple transformer, multiple constant flow module and multiple single-pole single-throw switch (SPST), corresponding with multiple batteries of connecting in battery pack respectively;
Wherein, the main coil of each transformer is connected with total charging and discharging circuit of battery pack; The secondary coil of each transformer, connects constant flow module and single-pole single-throw switch (SPST), and and a corresponding cell parallel;
The corresponding single-pole single-throw switch (SPST) of any one battery, when the control signal exported according to balance controller closes, makes the energy of battery pack through corresponding transformer, and the constant current controlled with corresponding constant flow module gives the charging of this battery.
Preferably, described circuit of battery pack balancing is also provided with energy compensation type circuit, wherein comprises further: a constant-current source, Constant Current Load, a double-point double-throw switch, and the multiple double-pole single throws corresponding with each battery in battery pack;
Wherein, the control signal that described double-point double-throw switch exports according to balance controller, selects to be connected by constant-current source or by Constant Current Load with each double-pole single throw;
Any one double-pole single throw and corresponding cell parallel, when the control signal exported according to balance controller closes, corresponding battery is connected with constant-current source or by Constant Current Load, by constant-current source, supplementing of constant current is carried out to this battery, or by Constant Current Load, this battery is carried out to the balanced discharge of constant current.
Preferably, any cluster battery, comprises multiple battery modules of series connection, and each battery module comprises multiple batteries of series connection;
Described Operation system setting has case equalizing system, wherein comprises further:
The balanced power supply of case, for this cluster battery provides euqalizing current, and is connected with AC network;
Battery pack control module, is connected by the first CAN power supply balanced with described case, provides and orders about the control signal of described case balanced power supply acquisition energy to respective battery modules equalizing charge;
Multiple battery monitoring module, corresponding with multiple battery module respectively, and respectively by the second CAN to be connected with described battery pack control module carry out mutual.
Preferably, described battery monitoring module is arranged in the battery case of battery module corresponding with it, gathers the information of this battery module.
Compared with prior art, the Li-ion batteries piles balanced management system that the utility model provides, cell balanced management, case equilibrium and bunch balanced management can be carried out, and effective portfolio effect means of testing is provided, the consistency of battery pack can be improved, meet the application demand of the large scale systems such as energy-accumulating power station.
Embodiment
The utility model passes through circuit of battery pack balancing, any one cell in the battery pack formed the multiple cell of series connection carries out equalizing charge or the balanced discharge of larger euqalizing current, to improve the consistency of battery pack, meet the application demand of the large scale systems such as energy-accumulating power station.In preferred example, use LiFePO
4as the ferric phosphate lithium cell of positive pole, the advantages such as have fail safe good, have extended cycle life, specific energy is high, and memory-less effect is easy to maintenance, production process green non-pollution.
As shown in Figure 1, described circuit of battery pack balancing, comprises: balance controller U, energy trasfer formula circuit and energy compensation type circuit.Wherein, described energy trasfer formula circuit, comprises: N number of transformer T1 ~ Tn, N number of constant flow module and N number of single-pole single-throw switch (SPST) KB1 ~ KBn.The total charging and discharging circuit of battery pack is connected with the main coil of N number of transformer, and the secondary coil of N number of transformer is in parallel with each cell B1 ~ Bn.
Described balance controller U realizes energy trasfer between battery by switch controlling signal.When supposing to need to shift energy to battery B1, B3, balance controller U outputs signal the commutating circuit that KB1, KB3 come turn-on battery B1, B3, at this moment the energy of whole Battery pack is charged to B1, B3 with constant current by transformer T1, T3, and the constant euqalizing current on cell circuit is controlled by constant flow module.
Described energy compensation type circuit, comprises: 1 constant-current source VS, 1 Constant Current Load R, 1 double-point double-throw switch KC and N number of double-pole single throw KA1 ~ KAn.N number of double-pole single throw KA1 ~ KAn is corresponding in parallel with each cell B1 ~ Bn; By double-point double-throw switch KC, in constant-current source VS or Constant Current Load R is connected with double-pole single throw KA1 ~ KAn.When the energy difference of certain batteries and whole Battery pack is too large, when can not be realized by the mode of energy trasfer at short notice, just need to use energy compensation type circuit.
Suppose that battery B2 is lower than the energy of other batteries a lot, by balance controller U Closing Switch KA2; Because K switch C acquiescence connects constant-current source VS, so at this moment carry out supplementing of constant current by constant-current source VS to battery B2.Suppose that battery B3 is higher much than the energy of other batteries, is first got to Constant Current Load R place, then by Closing Switch KA3, so just can be carried out the balanced discharge of constant current to battery B3 by Constant Current Load R by K switch C.
As shown in Figure 2, the utility model provides a kind of Li-ion batteries piles balance control method, when carrying out cell balanced management, first carrying out data prediction to battery pack equilibrium management system input battery data, comprising image data and basic parameter.
Wherein, image data comprises: electric current, monomer battery voltage, cell temperature.Basic parameter comprises: battery number, nominal capacity, balanced mark (for reading different characteristics), cell SOH(health status), cell SOC(state-of-charge), euqalizing current, time for balance, monomer lower threshold, monomer upper limit threshold, balance policy changes quiescent time, state duration, time for balance is set, the balanced duration, cell state (being mainly the equilibrium state of each cell), whole Battery pack state (mainly comprises charging and discharging state, open-circuit condition), the charge threshold table of electric voltage equalization and capacity equilibrium, the discharge threshold table of electric voltage equalization and capacity equilibrium, the open circuit threshold value table of electric voltage equalization and capacity equilibrium.
According to the equilibrium state that balanced rule exports, by the balanced realization unit (Fig. 3) arranged, balance protection is implemented to corresponding cell.Balanced realization adopts harmless charging modes efficiently, and its charging current can regulate according to the requirement of balanced rule, euqalizing current >=6A, and can realize point-to-point equilibrium.Balanced realization unit can be the part of each battery corresponding in the energy trasfer formula circuit or energy compensation type circuit controlled by balance controller in Fig. 1.If battery pack equilibrium management system is set as automatic equalization mode, then after condition adjudgement according to equalization discharge rule, the balanced rule of open circuit, charge balancing is regular carries out respective handling, control corresponding switch and carry out closing or disconnecting; If non-automatic balanced mode, then issue the charge and discharge balancing state of each battery.
In order to test portfolio effect, the battery pack formed with the 20Ah lithium batteries of 24 series connection in example, for tested object, adopts 0.5C discharge and recharge, be charged to group end voltage is set after charger electric current falls automatically.Wherein, use following tester, comprise: charger TCCH-H96V-50A, for charging; The FZMK of Gao Te company, i.e. adjustable load blocks, for electric discharge; The ESBMM of Gao Te company, i.e. battery monitoring module, for equilibrium test (euqalizing current 2 ~ 5A), voltage monitoring; The lithium battery monomer service equipment of Gao Te company, for the cell adjustment in balanced test process.
Described method of testing, comprises equalization discharge test and charge balancing test:
In equalization discharge test, comprise following process:
S1-1, whole battery pack is full of to electricity (and carried out adjusting to cell ensure often to save all to be full of) after, respectively capacity (making it bleed off portion capacity) is adjusted at random to wherein 4 batteries;
S1-2, carry out whole group of 0.5C electric discharge, close balanced, record data, do not add the original discharge curve of equalizing system when being illustrated in figure 4 the battery power discharge stage;
S1-3, to the charging of whole group of battery pack, monomer is by stopping (when any one battery is full of wherein stop);
S1-4, carry out whole group of 0.5C electric discharge, open balanced, record data, when being illustrated in figure 5 the battery power discharge stage, use the discharge curve after equalizing system.
In charge balancing test, comprise following process:
S2-1, on the basis of equalization discharge test, after (and carried out adjusting to cell ensure often to save all emptying) is discharged to whole group of battery pack, respectively capacity (making it be charged into portion capacity) adjusts at random to wherein 4 batteries;
2, carry out whole group of 0.5C charging, close balanced, record data, do not add the original charging curve of equalizing system when being illustrated in figure 6 the batteries charging stage;
3, to the electric discharge of whole group of battery pack, monomer is by stopping (stopping during any one battery emptying wherein);
4, carry out whole group of 0.5C charging, open balanced, record data, when being illustrated in figure 7 the batteries charging stage, use the charging curve after equalizing system.
Comparison chart 4 and Fig. 5, Fig. 6 and Fig. 7, after employing battery management system balanced management as seen, in charge and discharge process, the consistency of each cell improves greatly, and battery pack obtains efficient balance.
In addition, also case equilibrium and bunch balanced management is carried out, to solve the problem of circulation between battery by battery management system in the utility model.Due to the reason of inverter technology, in current Large Copacity energy-storage system, there is no to prevent very well the circuit of battery pack (or bunch) circulation, so in order to avoid the inside circulation of battery pack system or battery cluster system, can introduce battery case balancing equipment or battery bunch balancing equipment at some to the occasion that cost allows, this two classes balancing equipment effectively can reduce the scope that battery bunch circulation allows to system.Common energy-storage system, generally all considering from wherein selecting one from cost and setting angle, adopting battery case balancing equipment to prevent the circulation of energy-storage system in this example.
The framework of case equalizing system as shown in Figure 8, in Large Copacity energy-storage system, all contacted by more than 192 ~ 350 cells due to every cluster (or string) battery and form, these batteries can be divided into several battery modules, and general each battery module can be contacted by 12 or 24 batteries and be formed.Battery is in Long-Time Service process, difference due to individuality can cause the total voltage of each battery module possibility inconsistent, monomer equilibrium (circuit of battery pack balancing as described above) in battery module, can only all monomers of (in case) in oneself module be balanced to unanimously, consistency between module cannot ensure, PCS(energy conversion system) in whole bunch of battery charge or discharge process, the charging current of each module is duplicate, so just be easy to cause some module to overcharge or cross and put, some module charge less or owe to put.
For this reason, battery case balancing equipment (or battery module balancing equipment) is introduced in the utility model; Every bunch of (or string) power brick is containing 8 ~ 20 BMS(battery management systems) subsystem (each management subsystem 12 saves or 24 joint monomers); Each BMS subsystem runs relatively independent, cluster battery is by a lithium battery 45V or 90V/(3A ~ 6A) case balanced power supply euqalizing current is provided, by ESGU(battery pack control module) which case should be given battery balanced by CAN1 bus marco power supply, balance policy unifies computing and control by ESGU, in order to save cost, the equilibrium of battery case is realized by switching mode, and cluster (or string) battery has a corresponding casing balancer.
In the example of Fig. 8, ESBMM(battery monitoring module) can the every batteries voltage of on-line checkingi, temperature; Realize the Realtime Alerts to voltage, temperature over-range; Onsite alarming, dry contact exports closed, can realize far-end computer and report to the police and display alarm content; There is the online initiatively non-dissipative equalizing function of battery pack, by the online current charges of cell, electric discharge, improve consistency of battery pack, delay battery failure.
Described ESBMM, is fixed in each battery case, and the information that its voltage, electric current, temperature, SOC etc. detect is undertaken alternately by CAN2 bus and ESGU; The balanced power supply of case obtains energy from AC network and carries out equalizing charge to behindhand battery case, and the balanced power supply of case by CAN1 and ESGU communication, and controls by ESGU.
Described ESGU mainly collects the operation information of whole Battery pack, gathers total voltage and the electric current of whole Battery pack, reports to the police to the exception that battery pack occurs and protects; Can protect battery pack according to the requirement of safe handling rule; guarantee the safety of battery system, stable operation; when the abnormal failure situations such as battery severe overvoltage, under-voltage, overcurrent (short circuit), electric leakage (insulation) occur; energy-storage system administrative unit is given an order to this unit; control cut-offfing of whole Battery pack, avoid battery to be overcharged, cross and put and overcurrent.
In sum, the Li-ion batteries piles balanced management system that the utility model provides, cell balanced management, case equilibrium and bunch balanced management can be carried out, and effective portfolio effect means of testing is provided, the consistency of battery pack can be improved, meet the application demand of the large scale systems such as energy-accumulating power station.
Although content of the present utility model has done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to restriction of the present utility model.After those skilled in the art have read foregoing, for multiple amendment of the present utility model and substitute will be all apparent.Therefore, protection range of the present utility model should be limited to the appended claims.