CN117549796A - Control method for passive equalization of battery and vehicle - Google Patents
Control method for passive equalization of battery and vehicle Download PDFInfo
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- CN117549796A CN117549796A CN202311813766.7A CN202311813766A CN117549796A CN 117549796 A CN117549796 A CN 117549796A CN 202311813766 A CN202311813766 A CN 202311813766A CN 117549796 A CN117549796 A CN 117549796A
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- 238000000034 method Methods 0.000 title claims abstract description 35
- 230000003068 static effect Effects 0.000 claims abstract description 7
- 230000002045 lasting effect Effects 0.000 claims description 4
- 230000007958 sleep Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 12
- 239000000178 monomer Substances 0.000 description 9
- 238000003745 diagnosis Methods 0.000 description 4
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 230000005059 dormancy Effects 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
- B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
- B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
- B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L2240/00—Control parameters of input or output; Target parameters
- B60L2240/40—Drive Train control parameters
- B60L2240/54—Drive Train control parameters related to batteries
Abstract
The invention relates to a control method and vehicle of battery passive equalization, it is the technical field of battery, there are effects bad and problem of error equalization in the equalization of electric core in the prior art, the invention includes obtaining the initial value of equalization capacity difference, update the initial value of capacity difference when meeting the capacity difference and update the condition, if some electric core capacity difference is greater than presuming the threshold value, mark the electric core needs equalization; the capacity difference initial value updating conditions comprise: when the single voltage is in the non-platform area, the difference between the capacity difference of a certain cell and the minimum cell capacity difference is larger than a certain set range; and when the equivalent static condition of the battery core is met, updating and storing the initial value of the balance capacity difference, wherein the non-platform area comprises an interval with the SOC at the middle section and the SOC at the high and low sections, judging whether the condition for executing balance is met, and if so, starting balance on the battery core marked with balance, so that the balance effect is effectively improved.
Description
Technical Field
The invention relates to a control method for passive equalization of a battery and a vehicle, and belongs to the technical field of batteries.
Background
The lithium battery is a power source of the new energy automobile, but because the voltage, capacity and other parameters of the single battery are greatly different, the lithium battery is easy to be inconsistent in the use process, so that the battery performance is unstable, and the service life of the electric automobile is seriously influenced.
Since the lithium iron phosphate battery is a secondary battery, inconsistencies may occur during charge and discharge due to the difference in internal resistance and resistivity of the lithium iron phosphate battery, and in order to solve this problem, it is necessary to balance the unit cells so that the inconsistencies inside thereof are minimized as much as possible.
In the mixed lithium iron phosphate battery in the prior art, because of the extremely poor mapping relation of the OCV-SOC and the platform area of the OCV-SOC, the prior scheme mainly starts the differential pressure threshold according to fixed equalization, does not distinguish the platform area and the non-platform area of the battery, so that the SOC error is larger, or adopts a balance capacity differential equalization strategy, but marks the two ends of the balanced SOC, and the opportunity is often less; because the equalization mark error is large and the time is less, the problems of poor cell equalization effect and error equalization are caused, and the error equalization result is more easily caused.
Disclosure of Invention
The invention aims to provide a control method for passive equalization of a battery and a vehicle, which are used for solving the problems of poor battery cell equalization effect and error equalization of the existing lithium iron phosphate battery.
In order to achieve the above object, the present invention provides a method comprising:
the invention relates to a control method for passive equalization of a battery, which comprises the following steps:
1) Acquiring an initial value of the balance capacity difference, updating the initial value of the capacity difference when the capacity difference updating condition is met, and marking that the battery cell needs to be balanced if the capacity difference of a certain battery cell is larger than a set threshold value;
the capacity difference updating condition includes: when the single voltage is in a non-platform area, the difference value between a certain cell capacity difference and a minimum cell capacity difference is larger than a set certain range, and the equivalent static condition of a cell is met, updating and storing an initial value of the balanced capacity difference, wherein the non-platform area comprises an interval in which the SOC is in a middle section and the SOC is in two ends of a high section and a low section;
2) Judging whether the equalization executing condition is met, and if so, starting equalization for the battery cells marked with equalization.
The invention updates the acquired capacity difference, not only updates the initial value of the capacity difference between the high end section and the low end section of the SOC, but also increases the updating time of the initial value of the capacity difference of the middle section, so that the opportunity of updating the initial value of the capacity difference is increased; in addition, the static condition is replaced by the equivalent static condition, so that the capacity difference updating opportunity is further increased, the opportunity of starting the balance mark is further increased, and the balance effect is effectively improved.
Further, the cell equivalent rest condition includes that an absolute value of current is smaller than a set current threshold value, and a duration time is larger than a set time threshold value.
Considering that the characteristics of the battery in a small-current working mode for a long time are similar to those of the OCV-SOC under the standing condition, and the occurrence probability is more than that of the complete standing, the invention enables the current of the battery core to be smaller than a set certain threshold value and to last for a period of time to be equivalent to the standing of the battery core, and can ensure the precision of determining the battery core capacity difference while increasing the time of updating the capacity difference.
Further, the initial value of the capacity difference is obtained by reading the data stored in the memory before last dormancy, and is the initial value of the capacity difference at the time of last update.
The capacity difference is obtained by reading the memory, and the obtaining mode is quick and simple.
Further, the step 1) further includes balancing the cells according to the differential pressure marks: subtracting the minimum single voltage value from the real-time voltage value of each battery cell, and if the voltage difference of a certain battery cell is larger than the set balanced voltage difference threshold value, marking that the battery cell needs to be balanced.
The battery cell is marked by increasing the voltage difference of the battery cells to be larger than the set balanced voltage difference threshold value, so that the condition of certain battery cell leakage marks is avoided.
Further, when the balanced differential pressure threshold is set, a first threshold is set as the balanced differential pressure threshold when the battery cell is in the non-platform area, and a second threshold is set as the balanced differential pressure threshold when the battery cell is in the platform area, wherein the first threshold is smaller than the second threshold.
Because the differential pressure of the platform area and the non-platform area has different characteristics, the battery cell can be uniformly marked under the condition that each area meets the corresponding set threshold value through the different differential pressure thresholds arranged in the platform area and the non-platform area, and the marking accuracy is improved.
Further, the first threshold includes two values, namely a first value and a second value, wherein the first value is set as an equilibrium pressure difference threshold when the first value is in the middle section of the non-platform area, and the second value is set as an equilibrium pressure difference threshold when the second value is in the other section of the non-platform area, and the first value is an average value of the second threshold and the second value.
The marking equalization accuracy is effectively improved by dividing different thresholds in the middle section and other sections in the non-platform area.
Further, the conditions for performing equalization include the following: when the residual equilibrium capacity is more than or equal to the threshold capacity and the battery cell SOC difference is more than a set value; or the platform area differential pressure is larger than a set certain threshold value and lasts for a period of time, and the non-platform area differential pressure difference is larger than another set threshold value and lasts for a period of time; when the following conditions are satisfied simultaneously: whether the lowest single cell voltage is larger than a set threshold value, whether the lowest SOC is smaller than a set certain threshold value, and lasting for a certain time; whether the highest temperature of the equalization resistor is smaller than a certain threshold value or not; BMS failure level; BMS working state; equalizing and accumulating the starting time; the consistency of the battery cells is smaller; and (3) disabling the balanced faults in the non-outgoing line fault list.
By adding the external constraint condition for executing equalization, equalization is started when the conditions for marking equalization and executing equalization are simultaneously met, the problem of poor effect caused by equalization under the condition that the external conditions are not met is effectively avoided, and the reliability of the equalization effect can be ensured only if equalization is supported in all aspects, so that error equalization is avoided.
The invention relates to a control method for passive equalization of a battery, which comprises the following steps:
1) Subtracting the minimum single cell voltage value from the real-time voltage value of each single cell, and if the voltage difference of a certain cell is larger than a set equalization voltage difference threshold value, marking that the cell needs equalization;
the equalization pressure difference threshold setting mode is as follows: setting a first threshold value as an equilibrium pressure difference threshold value when the battery cell is in a non-platform area, and setting a second threshold value as an equilibrium pressure difference threshold value when the battery cell is in a platform area, wherein the first threshold value is smaller than the second threshold value;
2) Judging whether the equalization executing condition is met, and if so, starting equalization for the battery cells marked with equalization.
Further, the first threshold includes two values, namely a first value and a second value, wherein the first value is set as an equilibrium pressure difference threshold when the first value is in the middle section of the non-platform area, and the second value is set as an equilibrium pressure difference threshold when the second value is in the other section of the non-platform area, and the first value is an average value of the second threshold and the second value.
The marking equalization accuracy is effectively improved by dividing different thresholds in the middle section and other sections in the non-platform area.
Further, the conditions for performing equalization include the following: when the residual equilibrium capacity is more than or equal to the threshold capacity and the battery cell SOC difference is more than a set value; or the platform area differential pressure is larger than a set certain threshold value and lasts for a period of time, and the non-platform area differential pressure difference is larger than another set threshold value and lasts for a period of time; when the following conditions are satisfied simultaneously: whether the lowest single cell voltage is larger than a set threshold value, whether the lowest SOC is smaller than a set certain threshold value, and lasting for a certain time; whether the highest temperature of the equalization resistor is smaller than a certain threshold value or not; BMS failure level; BMS working state; equalizing and accumulating the starting time; the consistency of the battery cells is smaller; and (3) disabling the balanced faults in the non-outgoing line fault list.
By adding the external constraint condition for executing equalization, equalization is started when the conditions for marking equalization and executing equalization are simultaneously met, the problem of poor effect caused by equalization under the condition that the external conditions are not met is effectively avoided, and the reliability of the equalization effect can be ensured only if equalization is supported in all aspects, so that error equalization is avoided.
The vehicle comprises a processor, wherein the processor is used for executing the control method for the passive equalization of the battery of the hybrid vehicle.
Drawings
FIG. 1 is a graph showing the relationship between OCV and SOC in example 1 of a method for controlling the passive equalization of a battery according to the present invention;
FIG. 2 is a partial fault diagnosis chart used in example 1 of the control method of the battery passive equalization of the present invention;
fig. 3 is a graph of dynamic voltage Ucell-SOC in example 2 of the control method of the battery passive equalization of the present invention.
Detailed Description
The present invention will be further described in detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent.
The invention has the conception that: because the existing balancing strategy only depends on a dynamic voltage difference balancing method, does not distinguish between a battery platform area and a non-platform area, or does not adopt a balance capacity difference balancing method, or does not adopt a balance capacity difference balancing strategy in the balancing strategy, and does not adopt a method that the SOC is positioned in the middle section to update the capacity difference. The equalization external conditions are executed, mainly the additional constraint, the safety limit conditions for starting the equalization, and only if the marked equalization and the executed equalization external conditions are simultaneously met, the equalization is actually started.
Control method of battery passive equalization example 1:
the embodiment of the control method for the passive equalization of the battery adopts an equalization method based on capacity difference, and an intermediate section correction mark is added in the capacity difference equalization mark, and is specifically described below.
S1, balancing the marks based on the capacity difference, wherein the initial value of the balancing capacity difference is equal to the value obtained by reading EEPRON before last dormancy, and if the updating condition is met, updating the initial balancing capacity difference. If the difference in capacity of a certain battery is greater than a set threshold (a capacity difference corresponding to SOC 3%), this battery equalization is marked.
The capacity difference is used for representing the degree of poor consistency of the battery, and is more accurate than a pure dynamic pressure difference, and the specific formula is as follows:
（1）
（2）
remarks: in order to save chip resources, if the balance time is not required to be calculated, the balance time can be not calculated, and the capacity difference can be directly calculated, namely
。
Wherein: cellBalCurr is the real-time equilibrium current; cellVolt is the real-time cell voltage; res is the equilibrium resistance value; remainincellbaltime is the real-time residual equalization time; initCellCapacityDiff is the initial capacity difference; cellCapacityDiff is the difference in capacity; AFECellBalSts is the state that the battery cell is actually opened and balanced;
judging that the balance capacity difference is effective:
if the BMS stores the equalization capacity difference valid (NvmInitValidSts is valid (=1), or the read equalization capacity difference exceeds the normal range (SOC 0% -SOC 30%), the initial value of the equalization capacity difference is equal to the value stored by the EEPRON before the last sleep is read, otherwise, the initial value is equal to zero.
When NvmInitValidSts is valid (=1), software and hardware representing a capacity difference region of the storage device of the BMS system are valid; the capacity difference is limited in normal range before storage, generally, the capacity difference is multiplied by (0% -30% (refer to the SOC size)), if the capacity difference exceeds the capacity difference by 30%, the consistency of the battery core is estimated to be extremely serious, abnormal damage is possible, manual intervention and investigation are required, and the battery cannot be automatically repaired by balancing. And judging whether the storage is effective or not according to whether the capacity difference value of the read history storage exceeds the normal range.
And updating an algorithm strategy of the initial value of the capacity difference, namely calculating the SOC difference according to the OCV pressure difference of the battery cells when the static state and the voltage are in a non-platform period, converting the battery cell SOC difference into the capacity difference, and finally marking which battery cell needs to start battery cell equalization. If the BMS has an opportunity to obtain a new OCV value, the equalization capacity difference initial value should be updated.
The equalization capacity difference initial value should be recalculated to update when the battery OCV satisfies all of the following conditions:
a: the monomer voltage is in a region with better linear characteristics (the SOC of the lower section is more than or equal to 3% and less than or equal to 30%, the SOC of the middle section is more than or equal to 60% and less than or equal to 70%, and the SOC of the upper section is more than or equal to 98% and less than or equal to 100%).
The initial value of the updated balance capacity difference only considers the terminal voltage of the SOC and does not consider the middle section, so that the updating condition of 60 percent of the middle section is increased to be less than or equal to 70 percent of the SOC in the embodiment, SOCByOCV is obtained through static OCV-SOC table lookup, if the condition of updating the balance capacity difference in the middle section (the condition of 60 percent of the middle section is less than or equal to 70 percent of the SOC), the initial value of the capacity difference is updated, the updated capacity difference is multiplied by a coefficient (tentative 0.8) smaller than 1, and the value is latched when the voltage is lower.
The OCV-SOC is shown in FIG. 1, for example. In FIG. 1, the x-axis is SOC, 1% in units; the y-axis is temperature in degrees celsius; the data in the middle are open circuit voltage OCV, unit mV, and the SOC value at the corresponding temperature is found through the open circuit voltage OCV in the graph.
b：SOCcell-SOCcellmin≥3%。
The 3% specific parameters given in the condition b of the embodiment can be specifically set according to actual requirements, and in other embodiments, the specific parameters can be set as other parameters according to actual conditions so as to obtain better practical effects.
c: the equivalent standing is achieved, the absolute value of the Pack current is less than or equal to max (0.02C, 3A), and the duration is more than or equal to 30 minutes. If the equivalent standing time is equal to or longer than 30 minutes, the subsequent updating is performed every 3 minutes.
The duration is set to a specific value greater than or equal to 30 minutes, and may be specifically set according to actual requirements, and in other embodiments, may be set to other values according to actual situations.
S2, judging an executing balance condition, and starting balance if the executing balance condition is met.
The equalization conditions performed in this embodiment include the following: when the conditions A and B to I are satisfied at the same time, or the conditions J and B to I are satisfied at the same time, the cell equalization can be started.
A. The residual balance capacity is more than or equal to the threshold capacity, the SOC difference of the battery cells is more than or equal to 5%, and the corresponding battery cell balance is started.
The residual balance capacity represents the degree of poor consistency of the battery, namely the capacity value which needs to be balanced; the threshold capacity is a value that ensures excessive equalization and a certain margin value is given.
B. The lowest cell voltage is more than or equal to 3V or the lowest SOC is more than or equal to 10 percent (the charging state is not limited), and the duration is 5 seconds.
C. The highest temperature of the equalization resistor is less than or equal to 105 ℃, and if the heating is serious, the equalization can be carried out in turn in batches according to proportion.
D. Fltlevel_U8 is less than or equal to 2, BMS failure level.
Wherein the fault level of the BMS system is 5 levels in total, the greater the number is, the more serious the fault is, fltlevel_U8 is less than or equal to 2, and the fault level is not serious.
E. BMSSts, BMS working state, in one of the four states (Standby state, discharging state, charging state, remote monitoring state).
F. And during single power-on of the BMS system, the accumulated time of the balanced opening is less than or equal to 8h (the balanced time for the actual opening of the battery cell needs to be considered, and the balanced efficiency is required).
G. And an equalization fault (adhesion (opening and closing) fault of an equalization circuit, and mismatch between an equalization command and an actual state) occurs, and the duration is more than or equal to 5 seconds.
H. When the consistency of the battery cell is small (the maximum SOC difference is less than or equal to 25 percent, if the voltage difference is too large, the battery cell has other problems, and the battery cell cannot be repaired by passive balancing, and the battery cell needs to be checked and supplemented or replaced manually).
I. No failure (refer to the failure diagnosis list) in the failure diagnosis list, which inhibits equalization.
The failure diagnosis list has a large number of failures (134 in actual project products), and is partially shown in fig. 2, for example.
J. The differential pressure difference of UCellDiff of the platform area is more than or equal to 15mV; the differential pressure of UCellUDiff of the non-platform area is more than or equal to 80mV; for 30s.
K. Because the J pressure difference meets the balance condition of condition opening, the condition of pressure difference surge during high and low electric quantity is required to be additionally considered, the tentative maximum monomer voltage is less than or equal to 3.6V or the minimum monomer voltage is more than or equal to 3.0V, and the time lasts for 30 seconds.
L and J are in balance condition of condition opening, and the condition of increasing the pressure difference caused by current fluctuation is eliminated, wherein the current fluctuation is smaller (less than or equal to min (0.02C, 3A)/s) and lasts for 10s.
The specific values given by the judging voltage, duration, differential pressure, fault level and the like set in the equalizing condition in S2 can be set according to the actual requirements, and in other embodiments, the specific values can be set according to the actual conditions.
Control method of battery passive equalization example 2:
unlike embodiment 1, in S1, equalization marking is performed based on a real-time non-fixed dynamic differential pressure, and the minimum cell voltage value is subtracted according to the real-time voltage value of each cell, if the differential pressure of a certain cell is greater than a set equalization differential pressure threshold, the cell equalization is marked, and the equalization differential pressure threshold distinguishes a platform area from a non-platform area.
1) Cell non-plateau region: the difference of UCellDiff voltage difference is more than or equal to 80mV in the interval with better linear characteristics of the monomer voltage (SOC is more than or equal to 3% and less than or equal to 30%, SOC is more than or equal to 60% and less than or equal to 70%, SOC is more than or equal to 98% and the terminal voltage corresponding to the SOC).
2) Cell platform region: the difference of UCellDiff voltage difference is more than or equal to 15mV in the section with poor linear characteristic (30% < SOC <60%, 70% < SOC <98%, and corresponding terminal voltage).
Specific values of the differential pressure difference values are given in the cell platform area and the non-platform area, the differential pressure difference values can be set according to actual requirements, and in other embodiments, the differential pressure difference values can be set as other parameters according to corresponding different actual conditions so as to obtain better practical effects.
Based on actual use, when the battery BMS satisfies the following conditions, i.e., conditions a, b, c are all satisfied, a dynamic voltage difference is calculated and equalization is marked:
the signature equalization is as follows:
a) The differential pressure difference of UCellDiff of the platform area is more than or equal to 15mV; the differential pressure of UCellUDiff of the non-platform area is more than or equal to 80mV; the duration is not less than 30s.
b) Because the pressure difference meets the balance condition of conditional opening, the condition of pressure difference surge during high and low electric quantity is required to be additionally considered and excluded, the tentative maximum monomer voltage is less than or equal to 3.6V, the minimum monomer voltage is more than or equal to 3V, and the duration is more than or equal to 30s.
c) Because the differential pressure meets the balance condition of the condition opening, the condition of the differential pressure increase caused by current fluctuation needs to be additionally considered, the current fluctuation is smaller (less than or equal to min (0.02C, 3A)/s) and lasts more than or equal to 10s.
The cancellation flag is equalized as follows:
a) The dynamic differential pressure difference of UCellDiff of the platform area is less than or equal to 8mV; the dynamic differential pressure difference of UCellUDiff in the non-platform area is less than or equal to 40mV; the duration is not less than 30s.
b) Because the pressure difference meets the balance condition of conditional opening, the condition of pressure difference surge during high and low electric quantity is required to be additionally considered and excluded, the tentative maximum monomer voltage is less than or equal to 3.58V, the minimum monomer voltage is more than or equal to 3.1V, and the duration is more than or equal to 5s.
c) Because the differential pressure meets the balance condition of the condition opening, the condition of the differential pressure increase caused by current fluctuation needs to be additionally considered, and the current fluctuation is larger (more than or equal to min (0.018C, 2.5A)/s) and lasts more than or equal to 5s.
Similarly, compared with the conventional method, in the embodiment, on the basis of judging the threshold value of the non-platform area, the threshold value setting of a dynamic pressure difference mark is further added to the middle section (SOC is more than or equal to 60% and less than or equal to 70%), SOCByUcell obtained through dynamic voltage Ucell-SOC table lookup is adjusted, when the threshold value of the equilibrium pressure difference is adjusted from 80mV to 48mV (average value of 15mV of the platform area and 80mV of the non-platform area) in the middle section (SOC is more than or equal to 60% and less than or equal to 70%), and on the premise of guaranteeing non-misoperation equilibrium, the equilibrium accuracy is improved.
The dynamic voltage Ucell-SOC diagram is shown, for example, in FIG. 3.
The x-axis in FIG. 3 is SOC, unit 1%; the y-axis is temperature in degrees celsius; the z-axis is current multiplying power, unit C; the data in the middle are the dynamic terminal voltage Ucell, in mV.
Different from a normal table lookup using method, the input is y-axis temperature, z-axis current multiplying power and intermediate data dynamic terminal voltage Ucell, the output is x-axis SOC, and the corresponding SOC is obtained through the dynamic terminal voltage in the table lookup.
Specific values such as monomer voltage, duration and the like are given in the marking equalization and the canceling marking equalization, and can be set according to actual requirements, and in other embodiments, the specific values can be set as other parameters according to corresponding different actual conditions so as to obtain better practical effects.
Control method of battery passive equalization example 3:
on the basis of examples 1 and 2, step S1 is performed by performing equalization marking based on both real-time non-fixed dynamic pressure differences and capacity differences.
Vehicle embodiment:
an embodiment of a vehicle includes a processor that executes computer instructions to implement a method for controlling passive equalization of a battery, which is described in detail in embodiments 1, 2, and 3 above, and is not described here again.
Claims (12)
1. The control method of the passive equalization of the battery is characterized by comprising the following steps:
1) Acquiring an initial value of the balance capacity difference, updating the initial value of the capacity difference when the capacity difference updating condition is met, and marking that the battery cell needs to be balanced if the capacity difference of a certain battery cell is larger than a set threshold value;
the capacity difference updating condition includes: when the single voltage is in a non-platform area, the difference value between a certain cell capacity difference and a minimum cell capacity difference is larger than a set certain range, and the equivalent static condition of a cell is met, updating and storing an initial value of the balanced capacity difference, wherein the non-platform area comprises an interval in which the SOC is in a middle section and the SOC is in two ends of a high section and a low section;
2) Judging whether the equalization executing condition is met, and if so, starting equalization for the battery cells marked with equalization.
2. The method for controlling passive equalization of a battery of claim 1, wherein said cell equivalent rest condition comprises an absolute value of current less than a set current threshold and a duration greater than a set time threshold.
3. The method according to claim 1, wherein the initial capacity difference value is obtained by reading data stored in a memory before last sleep and is the initial capacity difference value at the time of last update.
4. The method for controlling passive equalization of a battery according to claim 1, wherein the step 1) further comprises the step of marking the cells to be equalized according to a pressure difference: subtracting the minimum single voltage value from the real-time voltage value of each battery cell, and if the voltage difference of a certain battery cell is larger than the set balanced voltage difference threshold value, marking that the battery cell needs to be balanced.
5. The method according to claim 4, wherein when the equalization pressure difference threshold is set, a first threshold is set as the equalization pressure difference threshold when the cell is in the non-plateau region, and a second threshold is set as the equalization pressure difference threshold when the cell is in the plateau region, and the first threshold is smaller than the second threshold.
6. The method according to claim 5, wherein the first threshold includes two values, a first value and a second value, respectively, the first value being set as an equilibrium pressure difference threshold when in a middle section of the non-plateau region, the second value being set as an equilibrium pressure difference threshold when in other sections of the non-plateau region, the first value being an average value of the second threshold and the second value.
7. The method for controlling passive equalization of a battery as defined in any one of claims 1-6, wherein the conditions for performing equalization include the following: when the residual equilibrium capacity is more than or equal to the threshold capacity and the battery cell SOC difference is more than a set value; or the platform area differential pressure is larger than a set certain threshold value and lasts for a period of time, and the non-platform area differential pressure difference is larger than another set threshold value and lasts for a period of time; when the following conditions are satisfied simultaneously: whether the lowest single cell voltage is larger than a set threshold value, whether the lowest SOC is smaller than a set certain threshold value, and lasting for a certain time; whether the highest temperature of the equalization resistor is smaller than a certain threshold value or not; BMS failure level; BMS working state; equalizing and accumulating the starting time; the consistency of the battery cells is smaller; and (3) disabling the balanced faults in the non-outgoing line fault list.
8. The control method of the passive equalization of the battery is characterized by comprising the following steps:
1) Subtracting the minimum single cell voltage value from the real-time voltage value of each single cell, and if the voltage difference of a certain cell is larger than a set equalization voltage difference threshold value, marking that the cell needs equalization;
the equalization pressure difference threshold setting mode is as follows: setting a first threshold value as an equilibrium pressure difference threshold value when the battery cell is in a non-platform area, and setting a second threshold value as an equilibrium pressure difference threshold value when the battery cell is in a platform area, wherein the first threshold value is smaller than the second threshold value;
2) Judging whether the equalization executing condition is met, and if so, starting equalization for the battery cells marked with equalization.
9. The method according to claim 8, wherein the first threshold includes two values, a first value and a second value, respectively, the first value being set as an equilibrium pressure difference threshold when in a middle section of the non-plateau region, the second value being set as an equilibrium pressure difference threshold when in other sections of the non-plateau region, the first value being an average value of the second threshold and the second value.
10. The control method of battery passive equalization according to claim 8 or 9, characterized in that the conditions for performing equalization include the following: when the residual equilibrium capacity is more than or equal to the threshold capacity and the battery cell SOC difference is more than a set value; or the platform area differential pressure is larger than a set certain threshold value and lasts for a period of time, and the non-platform area differential pressure difference is larger than another set threshold value and lasts for a period of time; when the following conditions are satisfied simultaneously: whether the lowest single cell voltage is larger than a set threshold value, whether the lowest SOC is smaller than a set certain threshold value, and lasting for a certain time; whether the highest temperature of the equalization resistor is smaller than a certain threshold value or not; BMS failure level; BMS working state; equalizing and accumulating the starting time; the consistency of the battery cells is smaller; and (3) disabling the balanced faults in the non-outgoing line fault list.
11. A vehicle comprising a processor, wherein the processor is configured to execute instructions to implement the method of controlling passive equalization of batteries of any of claims 1-7.
12. A vehicle comprising a processor, wherein the processor is configured to execute instructions to implement the method of controlling passive equalization of batteries of any of claims 8-10.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109742818A (en) * | 2018-12-18 | 2019-05-10 | 桑顿新能源科技有限公司 | Battery balanced appraisal procedure and device, computer equipment, storage medium |
| CN110994748A (en) * | 2019-12-31 | 2020-04-10 | 联动天翼新能源有限公司 | Lithium battery passive balance control method |
| CN112213648A (en) * | 2019-10-30 | 2021-01-12 | 蜂巢能源科技有限公司 | Method and device for judging battery cell balanced opening |
| US20210016680A1 (en) * | 2018-03-30 | 2021-01-21 | Byd Company Limited | Automobile, power battery pack equalization method and device |
| CN112909354A (en) * | 2019-11-19 | 2021-06-04 | 东莞新能源科技有限公司 | Battery module balancing method in battery circulation, electronic device and storage medium |
| WO2021143768A1 (en) * | 2020-01-19 | 2021-07-22 | 恒大新能源汽车投资控股集团有限公司 | Method and apparatus for equalizing charging of power battery, control device and storage medium |
| CN114513030A (en) * | 2022-02-15 | 2022-05-17 | 阳光储能技术有限公司 | Battery system, balance control method of battery system and power generation system |
| CN115021350A (en) * | 2022-06-14 | 2022-09-06 | 上海沃兰特航空技术有限责任公司 | Battery equalization method with large voltage leveling area |
| WO2023024851A1 (en) * | 2021-08-23 | 2023-03-02 | 深圳市道通科技股份有限公司 | Battery equalization method and system |
| CN115792644A (en) * | 2022-01-24 | 2023-03-14 | 浙江凌骁能源科技有限公司 | Power battery consistency calculation and verification method |
| CN117048426A (en) * | 2023-08-28 | 2023-11-14 | 重庆长安汽车股份有限公司 | Electric quantity balancing method and system for vehicle battery pack and vehicle |
-
2023
- 2023-12-27 CN CN202311813766.7A patent/CN117549796A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210016680A1 (en) * | 2018-03-30 | 2021-01-21 | Byd Company Limited | Automobile, power battery pack equalization method and device |
| CN109742818A (en) * | 2018-12-18 | 2019-05-10 | 桑顿新能源科技有限公司 | Battery balanced appraisal procedure and device, computer equipment, storage medium |
| CN112213648A (en) * | 2019-10-30 | 2021-01-12 | 蜂巢能源科技有限公司 | Method and device for judging battery cell balanced opening |
| CN112909354A (en) * | 2019-11-19 | 2021-06-04 | 东莞新能源科技有限公司 | Battery module balancing method in battery circulation, electronic device and storage medium |
| CN110994748A (en) * | 2019-12-31 | 2020-04-10 | 联动天翼新能源有限公司 | Lithium battery passive balance control method |
| WO2021143768A1 (en) * | 2020-01-19 | 2021-07-22 | 恒大新能源汽车投资控股集团有限公司 | Method and apparatus for equalizing charging of power battery, control device and storage medium |
| WO2023024851A1 (en) * | 2021-08-23 | 2023-03-02 | 深圳市道通科技股份有限公司 | Battery equalization method and system |
| CN115792644A (en) * | 2022-01-24 | 2023-03-14 | 浙江凌骁能源科技有限公司 | Power battery consistency calculation and verification method |
| CN114513030A (en) * | 2022-02-15 | 2022-05-17 | 阳光储能技术有限公司 | Battery system, balance control method of battery system and power generation system |
| CN115021350A (en) * | 2022-06-14 | 2022-09-06 | 上海沃兰特航空技术有限责任公司 | Battery equalization method with large voltage leveling area |
| CN117048426A (en) * | 2023-08-28 | 2023-11-14 | 重庆长安汽车股份有限公司 | Electric quantity balancing method and system for vehicle battery pack and vehicle |
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