Summary of the invention
The present invention is intended at least to solve one of technical problem existed in prior art.
For this reason, the object of the invention is to propose the good lithium ion battery method for separating of a kind of separation results uniformity.
To achieve these goals, lithium ion battery method for separating according to an embodiment of the invention, can comprise the following steps: A. charges to respectively multiple lithium ion battery and is full of; B. respectively charged maintenance is carried out to multiple described lithium ion battery; C. by lithium ion battery described in each, under the first discharge current multiplying power, constant-current discharge is to discharge cut-off voltage, and the discharge capacity recording now lithium ion battery described in each is the first discharge capacity C1; D. to lithium ion battery constant-current charge described in each to blanking voltage then constant-voltage charge to cut-off current; E. by lithium ion battery described in each, under the second discharge current multiplying power, constant-current discharge is to medium voltage, and the discharge capacity recording now lithium ion battery described in each is the second discharge capacity C2; F. under pulse charging current multiplying power, carry out pulse charge and pulsed discharge to lithium ion battery described in each, the time of described pulse charge and pulsed discharge is equal; G. lithium ion battery described in each is continued constant-current discharge to blanking voltage under the second discharge current multiplying power, record the 3rd discharge capacity C3 of lithium ion battery described in each; And H. carries out sorting according to described first discharge capacity C1, the second discharge capacity C2 and the 3rd discharge capacity C3 to described multiple lithium ion battery.
According to the lithium ion battery method for separating of the embodiment of the present invention, at least there is following beneficial effect:
1. a set of normal process of method establishment of the present invention, technical scheme integrality is good, and operability is good, can improve the efficiency of lithium ion battery sorting and combo, saves manpower, equipment and time cost;
2. method of the present invention comprises various battery behavior combo parameter detecting, considers that multiple parameter carries out sorting simultaneously, compares more comprehensively multiple battery, improves the uniformity of lithium ion battery combo, thus improves applicable performance and the life-span of battery pack;
3. combo capacity has taken into full account the calendar relaxation phenomenon of battery capacity, therefore adopts capacity after charged maintenance as normal capacity, is conducive to the uniformity improving the calendar decay that battery pack uses.
In addition, following additional technical feature can also be had according to the lithium ion battery method for separating of the embodiment of the present invention:
In one embodiment of the invention, described step H specifically comprises: H1. calculates mean value C1a and the mean square deviation C1s of the first discharge capacity C1 of described multiple lithium ion battery, if C1s/C1a is less than the first predetermined threshold value, then think that described multiple lithium ion battery of this batch is qualified, enter step H2; If H2. (the C1a-C1)/C1a that meets of described lithium ion battery is greater than the second predetermined threshold value, then thinks combo defective work, screen out described lithium ion battery; And H3. calculates the second discharge capacity and the 3rd discharge capacity sum C=(C2+C3 of lithium ion battery described in each), and calculate the mean value Ca of the described C of described multiple lithium ion battery, if (the Ca-C)/Ca that meets of described lithium ion battery is greater than the 3rd predetermined threshold value, then think combo defective work, screen out described lithium ion battery.
In one embodiment of the invention, described steps A specifically comprises: carry out constant-current charge respectively to charge cutoff voltage to multiple lithium ion battery.Consider battery pack in the method for this embodiment during combo capacity to charge when application process the approximate feature without constant voltage, utilize lack perseverance pressure-volume amount to carry out sorting as normal capacity to multiple battery, fully can ensure the Capacity uniformity of battery in battery pack.
In one embodiment of the invention, the process of described charged maintenance comprises: between low temperature and high temperature, select multiple temperature spot to circulate, and described multiple lithium ion battery is left standstill a period of time at each temperature spot.The storage condition temperature of lithium ion battery is carried out temperature cycles between low temperature, normal temperature, high temperature, and object detects each battery to the tolerance of temperature.In this embodiment, during charged maintenance, adopt multiple temperature spot circulation impact, be conducive to eliminating the inconsistency that when battery pack uses, temperature shock causes.
In one embodiment of the invention, the time span of described pulse charge and pulsed discharge is less than 1min.Time of pulse charge and pulsed discharge is unsuitable oversize, oversizely may impact the charging capacity of battery.
In one embodiment of the invention, also comprise step after described step G: to lithium ion battery constant-current charge described in each to blanking voltage then constant-voltage charge to cut-off current.This step is full of for charging to battery for the last time, and the battery after being full of directly can enter next assembling link after sorting or sale is dispatched from the factory.
In one embodiment of the invention, described in when carrying out short time pulse charge, also comprise step: calculate charging DC internal resistance Rc; And after described step H, also comprise step: the mean value Rca calculating the described DC charging internal resistance Rc of described multiple lithium ion battery, if meeting of described lithium ion battery | Rca-Rc|/Rca is greater than the 4th predetermined threshold value, then think combo defective work, screens out described lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.
In one embodiment of the invention, described in when carrying out short time pulsed discharge, also comprise step: calculate electric discharge DC internal resistance Rd; And after described step H, also comprise step: the mean value Rda calculating the described direct-current discharge internal resistance Rd of described multiple lithium ion battery, if meeting of described lithium ion battery | Rda-Rd|/Rda is greater than the 5th predetermined threshold value, then think combo defective work, screens out described lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.
In one embodiment of the invention, also step is comprised: first time is carried out to lithium ion battery described in each and measures between described steps A and B, to obtain the first AC internal Resistance r1 of lithium ion battery described in each, and also comprise step after described step H: the mean value r1a calculating the described first AC internal Resistance r1 of described multiple lithium ion battery, if meeting of described lithium ion battery | r1a-r1|/r1a is greater than the 6th predetermined threshold value, then think combo defective work, screen out described lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.Further, in this embodiment, for the combo parameter of battery analysis introduces DC internal resistance.Only consider AC internal Resistance in correlation technique, and the result that AC internal Resistance detects has very large unstability and randomness.On the contrary, the result of DC internal resistance repeated detection has stability, conforming feature, and high rate performance when battery pack uses is determined by DC internal resistance.Therefore be conducive in combo parameter introducing DC internal resistance the accuracy improving lithium ion battery combo.
In one embodiment of the invention, also step is comprised: second time is carried out to lithium ion battery described in each and measures between described step B and C, to obtain the second AC internal Resistance r2 of lithium ion battery described in each, and also comprise step after described step H: the mean value r2a calculating the described second AC internal Resistance r2 of described multiple lithium ion battery, if meeting of described lithium ion battery | r2a-r2|/r2a is greater than the 7th predetermined threshold value, then think combo defective work, screen out described lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.Further, in this embodiment, for the combo parameter of battery analysis introduces DC internal resistance.Only consider AC internal Resistance in correlation technique, and the result that AC internal Resistance detects has very large unstability and randomness.On the contrary, the result of DC internal resistance repeated detection has stability, conforming feature, and high rate performance when battery pack uses is determined by DC internal resistance.Therefore be conducive in combo parameter introducing DC internal resistance the accuracy improving lithium ion battery combo.
Additional aspect of the present invention and advantage will part provide in the following description, and part will become obvious from the following description, or be recognized by practice of the present invention.
Detailed description of the invention
Be described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the present invention, and can not limitation of the present invention be interpreted as.
The present invention is intended to propose a kind of lithium ion battery method for separating, the method has taken into full account that battery pack is similar to the parameter such as capacity characteristic, high rate charge-discharge adaptability, storage capacity difference, temperature stress characteristic, DC internal resistance without constant-voltage charge, can to sorting battery without differences combo, the uniformity of battery pack can be improved, combo efficiency can be improved again.
As shown in Figure 1, according to the lithium ion battery method for separating of the embodiment of the present invention, can comprise the following steps:
A. multiple lithium ion battery is charged to respectively and be full of.
B. respectively charged maintenance is carried out to multiple lithium ion battery.
C. by each lithium ion battery, under the first discharge current multiplying power, constant-current discharge is to discharge cut-off voltage, and the discharge capacity recording now each lithium ion battery is the first discharge capacity C1.
D. to each lithium ion battery constant-current charge to blanking voltage then constant-voltage charge to cut-off current.
E. by each lithium ion battery, under the second discharge current multiplying power, constant-current discharge is to medium voltage, and the discharge capacity recording now each lithium ion battery is the second discharge capacity C2.
F. under pulse charging current multiplying power, carry out pulse charge and pulsed discharge to each lithium ion battery, the time of pulse charge and pulsed discharge is equal.
G. each lithium ion battery is continued constant-current discharge to blanking voltage under the second discharge current multiplying power, record the 3rd discharge capacity C3 of each lithium ion battery.
H. according to the first discharge capacity C1, the second discharge capacity C2 and the 3rd discharge capacity C3, sorting is carried out to multiple lithium ion battery.
The lithium ion battery method for separating of this embodiment, at least has following beneficial effect:
1. a set of normal process of method establishment of the present invention, technical scheme integrality is good, and operability is good, can improve the efficiency of lithium ion battery sorting and combo, saves manpower, equipment and time cost;
2. method of the present invention comprises various battery behavior combo parameter detecting, considers that multiple parameter carries out sorting simultaneously, compares more comprehensively multiple battery, improves the uniformity of lithium ion battery combo, thus improves applicable performance and the life-span of battery pack;
3. combo capacity has taken into full account the calendar relaxation phenomenon of battery capacity, therefore adopts capacity after charged maintenance as normal capacity, is conducive to the uniformity improving the calendar decay that battery pack uses.
In addition, following additional technical feature can also be had according to the lithium ion battery method for separating of the embodiment of the present invention:
In one embodiment of the invention, step H specifically comprises:
H1. calculate mean value C1a and the mean square deviation C1s of the first discharge capacity C1 of multiple lithium ion battery, if C1s/C1a is less than the first predetermined threshold value, then thinks that multiple lithium ion batteries of this batch are qualified, enter step H2.In other words, if the variance of multiple lithium ion batteries of this batch is too large, directly all superseded.
If H2. (the C1a-C1)/C1a that meets of lithium ion battery is greater than the second predetermined threshold value, then thinks combo defective work, screen out lithium ion battery.In other words, if the C1 of part lithium ion battery is less in this batch, need to screen out this lithium ion battery.
H3. the second discharge capacity and the 3rd discharge capacity sum C=(C2+C3 of each lithium ion battery is calculated), and calculate the mean value Ca of the C of multiple lithium ion battery, if (the Ca-C)/Ca that meets of lithium ion battery is greater than the 3rd predetermined threshold value, then think combo defective work, screen out lithium ion battery.In other words, if (C2+C3) of part lithium ion battery is less in this batch, need to screen out this lithium ion battery.
In one embodiment of the invention, steps A specifically comprises: carry out constant-current charge respectively to charge cutoff voltage to multiple lithium ion battery.Consider battery pack in the method for this embodiment during combo capacity to charge when application process the approximate feature without constant voltage, utilize lack perseverance pressure-volume amount to carry out sorting as normal capacity to multiple battery, fully can ensure the Capacity uniformity of battery in battery pack.
In one embodiment of the invention, the process of charged maintenance comprises: between low temperature and high temperature, select multiple temperature spot to circulate, multiple lithium ion battery is left standstill a period of time at each temperature spot.The storage condition temperature of lithium ion battery is carried out temperature cycles between low temperature, normal temperature, high temperature, and object detects each battery to the tolerance of temperature.In this embodiment, during charged maintenance, adopt multiple temperature spot circulation impact, be conducive to eliminating the inconsistency that when battery pack uses, temperature shock causes.
In one embodiment of the invention, the time span of pulse charge and pulsed discharge is less than 1min.Time of pulse charge and pulsed discharge is unsuitable oversize, oversizely may impact the charging capacity of battery.
In one embodiment of the invention, also comprise step after step G: to each lithium ion battery constant-current charge to blanking voltage then constant-voltage charge to cut-off current.This step is full of for charging to battery for the last time, and the battery after being full of directly can enter next assembling link after sorting or sale is dispatched from the factory.
In one embodiment of the invention, when carrying out short time pulse charge, also step is comprised: calculate charging DC internal resistance Rc; And after step H, also comprising step: the mean value Rca calculating the DC charging internal resistance Rc of multiple lithium ion battery, if lithium ion battery is satisfied | Rca-Rc|/Rca is greater than the 4th predetermined threshold value, then think combo defective work, screen out lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.
In one embodiment of the invention, when carrying out short time pulsed discharge, also step is comprised: calculate electric discharge DC internal resistance Rd; And after step H, also comprising step: the mean value Rda calculating the direct-current discharge internal resistance Rd of multiple lithium ion battery, if lithium ion battery is satisfied | Rda-Rd|/Rda is greater than the 5th predetermined threshold value, then think combo defective work, screen out lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.
In one embodiment of the invention, also step is comprised: first time is carried out to each lithium ion battery and measures between steps A and B, to obtain the first AC internal Resistance r1 of each lithium ion battery, and also comprise step after step H: the mean value r1a calculating the first AC internal Resistance r1 of multiple lithium ion battery, if meeting of lithium ion battery | r1a-r1|/r1a is greater than the 6th predetermined threshold value, then think combo defective work, screen out lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.Further, in this embodiment, for the combo parameter of battery analysis introduces DC internal resistance.Only consider AC internal Resistance in correlation technique, and the result that AC internal Resistance detects has very large unstability and randomness.On the contrary, the result of DC internal resistance repeated detection has stability, conforming feature, and high rate performance when battery pack uses is determined by DC internal resistance.Therefore be conducive in combo parameter introducing DC internal resistance the accuracy improving lithium ion battery combo.
In one embodiment of the invention, also step is comprised: second time is carried out to each lithium ion battery and measures between step B and C, to obtain the second AC internal Resistance r2 of each lithium ion battery, and also comprise step after step H: the mean value r2a calculating the second AC internal Resistance r2 of multiple lithium ion battery, if meeting of lithium ion battery | r2a-r2|/r2a is greater than the 7th predetermined threshold value, then think combo defective work, screen out lithium ion battery.In this embodiment, set up a sorting Consideration, assorting room is more comprehensive, and the result of battery group is more reliable, uniformity good.Further, in this embodiment, for the combo parameter of battery analysis introduces DC internal resistance.Only consider AC internal Resistance in correlation technique, and the result that AC internal Resistance detects has very large unstability and randomness.On the contrary, the result of DC internal resistance repeated detection has stability, conforming feature, and high rate performance when battery pack uses is determined by DC internal resistance.Therefore be conducive in combo parameter introducing DC internal resistance the accuracy improving lithium ion battery combo.
It should be noted that, the essence of above-mentioned lithium ion battery sorting schemes is " test various index, screen out the lithium ion battery that capacity performance index is too small, and screen out the excessive lithium ion battery of various resistance indicator deviation ".All indexs can be adopted to carry out sorting as standard, also can only adopt part index number to carry out sorting as standard.When adopting multiple index to carry out sorting as standard, order wherein can adjust flexibly, can with successively, rear first or carry out simultaneously, do not affect principle of the present invention.
For making those skilled in the art understand the present invention better, continue the lithium ion battery method for separating of a statement specific embodiment below.
Step (1): constant-current charge
First cabinet is tested by each lithium ion battery, open circuit standing a period of time (general more than 30 minutes) reaches temperature and electrochemical equilibrium, then with certain current ratio (below general 5 multiplying powers) constant current charge to upper limit blanking voltage (different according to different lithium ion battery material system producer regulation), under finally leaving standstill certain hour (within general 30 minutes), next step processing step waited for by cabinet.
Step (2): first time AC internal Resistance measurement
Step (1) terminates (within general 1 hour) in rear certain hour, measures the AC internal Resistance r1 of all lithium ion batteries and record with Ac internal resistance instrument (1kHz).
Step (3): charged maintenance
Step (2) terminates in rear certain hour (within general 1 hour), lithium ion battery is carried out temperature cycles between low temperature (general more than-5 DEG C) and high temperature (general less than 45 DEG C) and shelves (general 7 days of the time of shelving, generally select low temperature, normal temperature, high temperature 3 to 5 temperature spots to circulate, each temperature spot shelves 1 to 2 days time.Final step shelve environment temperature preferably normal temperature, the electrochemical equilibrium being conducive to reaching lithium ion battery carries out next step test).
Step (4): second time AC internal Resistance is measured
Step (3) terminates (within general 1 hour) in rear certain hour, measures the AC internal Resistance r2 of all lithium ion batteries and record with Ac internal resistance instrument (1kHz).
Step (5): combo parameter measurement
Step (4) terminates in rear certain hour (within general 1 hour), and lithium ion battery Over-The-Counter carries out volume test, specific as follows.
Step (5.1): lithium ion battery leaves standstill certain hour (within general 30 minutes); Then different according to different lithium ion battery material system producer regulation to discharge cut-off voltage with certain multiplying power (below general 10C multiplying power) constant current discharge), record this discharge capacity C1.
Step (5.2): leave standstill certain hour (within general 30 minutes).
Step (5.3): with certain current ratio (within general 5C multiplying power) constant current charge to the identical charge cutoff voltage of step (1), then constant voltage charges to cut-off current (general more than 0.02C).
Step (5.4): leave standstill certain hour (within general 30 minutes).
Step (5.5): with certain multiplying power (general 1C multiplying power) constant current discharge to certain medium voltage middle (voltage of general corresponding 30% ~ 70%SOC), record discharge capacity C2.
Step (5.6): leave standstill certain hour (within general 30 minutes).
Step (5.7): with certain multiplying power pulse charge (general 10 seconds, 10C), calculates charging DC internal resistance Rc; Then leave standstill certain hour (within general 1 minute), finally with certain multiplying power pulsed discharge (general 10 seconds, 10C), calculate electric discharge DC internal resistance Rd.
Step (5.8): leave standstill certain hour (within general 5 minutes).
Step (5.9): with the identical multiplying power constant current discharge of step (5.5) to discharge cut-off voltage, record discharge capacity C3.
Step (5.10): leave standstill certain hour (within general 5 minutes).
Step (5.11): with certain current ratio (within general 5C multiplying power) constant current charge to the identical charge cutoff voltage of step (1), then constant voltage charges to cut-off current (general more than 0.02C).
Step (5.12): leave standstill certain hour (within general 5 minutes).
Step (6): be lithium ion battery sorting.
Step (6.1): C1 value sorts and asks mean value C1a and the mean square deviation C1s of C1 by measure.If C1s/C1a is less than the value (within general 10%) of certain regulation, then thinks that this batch of lithium ion battery is qualified, thus carry out following sorting.
Step (6.2): C1 value sequence by measure, if (C1a-C1)/C1a is greater than certain setting (within general 5%), then excludes the lithium ion battery of this capacity, think combo defective work.
Step (6.3): C=(C2+C3) value sequence by measure, and ask the mean value Ca of C, if (Ca-C)/Ca is greater than certain setting (within general 5%), then the lithium ion battery of this capacity is excluded, think combo defective work.
Step (6.4): sort and the Rda that averages by direct-current discharge internal resistance Rd value, if | the value of Rda-Rd|/Rda is greater than certain setting (within general 10%), then by should direct-current discharge internal resistance lithium ion battery get rid of.
Step (6.5): sort and the Rca that averages by DC charging internal resistance Rc value, if | the value of Rca-Rc|/Rca is greater than certain setting (within general 10%), then by should direct-current discharge internal resistance lithium ion battery get rid of.
Step (6.6): sort and the r1a that averages by the first AC internal Resistance r1 value, if | the value of r1a-r1|/r1a is greater than certain setting (within general 15%), then by should direct-current discharge internal resistance lithium ion battery get rid of.
Step (6.7): sort and the r2a that averages by the second AC internal Resistance r2 value, if | the value of r2a-r2|/r2a is greater than certain setting (within general 15%), then by should direct-current discharge internal resistance lithium ion battery get rid of.
Step (6.8): the lithium ion battery remaining through previous step sorting all thinks combo certified products, and these lithium ion batteries are no longer distinguished, and random selecting lithium ion battery carries out lithium ionic cell module combo from these lithium ion batteries.
As from the foregoing, the lithium ion battery method for separating of this embodiment at utmost increases the synergy of parameters investigation, makes the spec battery uniformity that sorts out good.Standard compliant lithium ion battery is no longer distinguished, and combo can use arbitrarily, can save a large amount of combo time and manpower in application process.
In addition, term " first ", " second " only for describing object, and can not be interpreted as instruction or hint relative importance or imply the quantity indicating indicated technical characteristic.Thus, be limited with " first ", the feature of " second " can express or impliedly comprise one or more these features.In describing the invention, the implication of " multiple " is two or more, unless otherwise expressly limited specifically.
In the description of this description, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present invention or example.In this manual, to the schematic representation of above-mentioned term not must for be identical embodiment or example.And the specific features of description, structure, material or feature can combine in one or more embodiment in office or example in an appropriate manner.In addition, the different embodiment described in this description or example can carry out combining and combining by those skilled in the art.
Although illustrate and describe embodiments of the invention above, be understandable that, above-described embodiment is exemplary, can not be interpreted as limitation of the present invention, and those of ordinary skill in the art can change above-described embodiment within the scope of the invention, revises, replace and modification.