A kind of safe lithium battery group balance realizing methodTechnical field
The invention belongs to battery technology field, in particular to a kind of safe lithium battery group balance realizing method.
Background technique
Hail exhibition along with economic and scientific and technological speed, the situation of environmental pollution and shortage of resources is also increasingly sharpened, this notNew-energy automobile has mirrored everybody eyes under reconcilable contradiction, has been pulled to peak mouth top of the waves；The industrial chain that it drives is immediatelyAlso four improvement of sound of the wind, wherein the most significant with dynamic lithium battery industry；Common lithium battery have ternary, LiFePO4, LiMn2O4,Lithium titanate etc. is not very enumerated, these lithium material battery cores by it is different string and in a manner of be combined into battery pack, be widely used in EV, PHEV, HEVVehicle and energy storage market.Since lithium material battery core is highly prone to the influence of environment, production technology in process of production, make one to propertyIt is deteriorated, even the single battery core with batch production；The performance parameters such as its voltage, internal resistance, self-discharge rate, capacity also have difference；It is especially more more aobvious in the capacity volume variance after multiple charge-discharge cycle between single battery core, seriously affect the use of battery systemService life；The difference of battery system capacity is extremely easy to cause vehicle the peaces such as cast anchor, moment broken height pressure, power steering fail occurFull problem, therefore a kind of balancer of enough maintenance battery powers balance that can be safe and stable of demand is very urgent, and instituteThe Balance route strategy for stating device is even more core.
Existing Balance route control strategy, majority are from the characterize data such as voltage and estimated data of battery core as judgementCondition carries out equilibrium to battery core, and estimated data and characterize data all have uncertainty, have to the battery pack system just to have dispatched from the factory brightAobvious effect, but biggish balanced mistaken ideas there is for the battery pack of operation after a period of time；Voltage data is balancing procedureThe important ginseng of a project；When battery core one is poor to property, voltage characteristic has deviated from the characteristic of script with easy indicatrixWhen, the effect of reverse side can be then obtained, more balanced actual capacity is caused as Rule of judgment by this characterize data of voltage at this timeDifference is bigger.
Summary of the invention
The object of the present invention is to provide a kind of safe lithium battery group balance realizing method, solve in the prior art due toBalanced maloperation cause battery consistency difference worse and worse the technical issues of.
To achieve the above object, the invention adopts the following technical scheme:
A kind of safe lithium battery group balance realizing method, comprising the following steps:
Step 1: a discharge equalizing circuit is all connected on each of battery pack battery, discharge equalizing circuit includesSwitch S and resistance R, switch S and resistance R are connected in series；
Step 2: acquiring the voltage value of each battery, position the position of three highest single batteries of voltage value, recordThe position of these three single batteries；The position for positioning three minimum single batteries of voltage value, records these three single batteriesPosition；
Step 3: using highest voltage value in three highest single batteries of voltage value as maximum voltage value, by three electricityPressure is worth voltage value minimum in minimum single battery as minimum amount of voltage that, judges between maximum voltage value and minimum amount of voltage thatDifference whether be greater than n millivolts: be then to meet condition；
Step 4: judging whether maximum voltage value is greater than a millivolts: being, then meet condition；
Step 5: whether the current maximum monomer of detection is identified as capacity short slab: it is no, then meet condition；
Step 6: using the result of the result of step 3, step 4 and step 5 as judgment basis, when all meeting, controlSwitch S closure, makes discharge equalizing circuit carry out equalization discharge.
All batteries in the battery pack are to be connected in series.
All batteries in the battery pack are equipped with number, and the position of single battery is number corresponding to the battery.
When executing step 5, the capacity short slab is defined as: eliminating gathering line connectivity problem or other row's connectionsAfter problem, voltage highest when charging, voltage minimum battery when electric discharge is then defined as capacity short slab；Only work as in confirmationPreceding battery does not have just to allow when capacity short slab problem balanced；
Judge that the step of whether battery is capacity short slab is as follows:
Step S1: in battery system charge and discharge cycles, relevant critical data is recorded, the critical data includesMonomer battery voltage data, single battery remaining capacity data, temperature data and current data；
Step S2: analyzing the critical data, positions the position of the single battery of minimum voltage, records monomer electricityPond；
Step S3: after carrying out multiple battery system charge and discharge cycles, the minimum historical data of monomer voltage is generated；Retrieve monomerThe minimum historical data of voltage finds out the highest single battery Bn of the frequency of occurrences；
Step S4: the voltage status at the end of analysis single battery Bn charging, if the voltage value of single battery Bn is batteryMaximum value in group, then marking single battery Bn is capacity short slab.
A kind of safe lithium battery group balance realizing method of the present invention solves in the prior art since equilibrium missesOperation cause battery consistency difference worse and worse the technical issues of, the present invention is suitable for actively and passively balanced；It improvesThe certainty and high efficiency of weighing apparatus；The stability for improving electrokinetic cell system of high degree, safety；Safety to vehicle andSolid foundation has been established in stable operation.
Detailed description of the invention
Fig. 1 is the flow chart of Balance route strategy of the invention；
Fig. 2 is capacity short slab overhaul flow chart of the invention；
Fig. 3 is balancing control circuit of the invention.
Specific embodiment
A kind of safe lithium battery group balance realizing method as shown in FIG. 1 to FIG. 3, comprising the following steps:
Step 1: a discharge equalizing circuit is all connected on each of battery pack battery, discharge equalizing circuit includesSwitch S and resistance R, switch S and resistance R are connected in series；
Step 2: acquiring the voltage value of each battery, position the position of three highest single batteries of voltage value, recordThe position of these three single batteries；The position for positioning three minimum single batteries of voltage value, records these three single batteriesPosition；
Step 3: using highest voltage value in three highest single batteries of voltage value as maximum voltage value, by three electricityPressure is worth voltage value minimum in minimum single battery as minimum amount of voltage that, judges between maximum voltage value and minimum amount of voltage thatDifference whether be greater than n millivolts: be then to meet condition；；
Step 4: judging whether maximum voltage value is greater than a millivolts: being, then meet condition；；
Step 5: whether the current maximum monomer of detection is identified as capacity short slab: it is no, then meet condition；
Step 6: using the result of the result of step 3, step 4 and step 5 as judgment basis, when all meeting, controlSwitch S closure, makes discharge equalizing circuit carry out equalization discharge.
All batteries in the battery pack are to be connected in series.
All batteries in the battery pack are equipped with number, and the position of single battery is number corresponding to the battery.
When executing step 5, the capacity short slab is defined as: eliminating gathering line connectivity problem or other row's connectionsAfter problem, voltage highest when charging, voltage minimum battery when electric discharge is then defined as capacity short slab；Only work as in confirmationPreceding battery does not have just to allow when capacity short slab problem balanced；
Judge that the step of whether battery is capacity short slab is as follows:
Step S1: in battery system charge and discharge cycles, relevant critical data is recorded, the critical data includesMonomer battery voltage data, single battery remaining capacity data, temperature data and current data；
Step S2: analyzing the critical data, positions the position of the single battery of minimum voltage, records monomer electricityPond；
Step S3: after carrying out multiple battery system charge and discharge cycles, the minimum historical data of monomer voltage is generated；Retrieve monomerThe minimum historical data of voltage finds out the highest single battery Bn of the frequency of occurrences；
Step S4: the voltage status at the end of analysis single battery Bn charging, if the voltage value of single battery Bn is batteryMaximum value in group, then marking single battery Bn is capacity short slab.
The present invention can be used as an important module in BMS, the present invention passive balanced application on ferric phosphate lithium cellProcess it is as follows:
Step A: the method according to step 2 obtains the position of highest three battery cores of voltage and storage in battery packIts voltage value Vmax1, Vmax2, Vmax3；It obtains the position for three battery cores that voltage is low in battery pack and stores its voltage valueVmin1,Vmin2,Vmin3；
Step B: the method according to step 3, detect maximum monomer and minimum monomer pressure difference △ V, if △ V > nWhen mV (10mV < n < 100mV), then meet condition；The possible user's demand of n value is determined；
Step C: detection maximum monomer voltage Vmax is greater than a mV (3350mV < a < 3600mV), is then to meet condition；
Step D: whether the current maximum monomer of detection is identified as capacity short slab, no, then meets condition；
Step E: when the result of the result of step B, the result of step C and step D all meets, with the single battery pairThe switch S closure answered, makes discharge equalizing circuit carry out equalization discharge.
A kind of safe lithium battery group balance realizing method of the present invention solves in the prior art since equilibrium missesOperation cause battery one to sex differernce worse and worse the technical issues of, the present invention is suitable for actively and passively balanced；It improvesThe certainty and high efficiency of weighing apparatus；The stability for improving electrokinetic cell system of high degree, safety；Safety to vehicle andSolid foundation has been established in stable operation.