CN116520164A - Lithium battery electricity metering management system and electricity metering management method - Google Patents
Lithium battery electricity metering management system and electricity metering management method Download PDFInfo
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 53
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 53
- 238000007726 management method Methods 0.000 title claims abstract description 25
- 230000005611 electricity Effects 0.000 title claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 61
- 230000008569 process Effects 0.000 claims abstract description 28
- 238000005259 measurement Methods 0.000 claims abstract description 26
- 238000007599 discharging Methods 0.000 claims abstract description 22
- 238000012544 monitoring process Methods 0.000 claims abstract description 6
- 238000012360 testing method Methods 0.000 claims abstract description 3
- 238000005070 sampling Methods 0.000 claims description 69
- 238000011156 evaluation Methods 0.000 claims description 7
- 230000008859 change Effects 0.000 claims description 6
- 238000003869 coulometry Methods 0.000 claims description 5
- 238000013507 mapping Methods 0.000 claims description 5
- 230000035772 mutation Effects 0.000 claims description 3
- 238000012216 screening Methods 0.000 claims description 2
- 230000010354 integration Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 4
- 238000012937 correction Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 108010076504 Protein Sorting Signals Proteins 0.000 description 1
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- 239000003990 capacitor Substances 0.000 description 1
- 230000032677 cell aging Effects 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/378—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
- G01R31/3842—Arrangements for monitoring battery or accumulator variables, e.g. SoC combining voltage and current measurements
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E60/10—Energy storage using batteries
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Abstract
The invention discloses a lithium battery electricity metering management system and an electricity metering management method, wherein the method comprises the following steps: obtaining voltage measurement curves at all temperatures in advance; dispersing the voltage measurement curve into a plurality of parts, and calibrating each discrete point by using the residual capacity; acquiring the current temperature of a battery in the equipment, and acquiring a matched target curve from each voltage test curve according to the current temperature; measuring the current voltage of a battery in the equipment at the current moment, and finding out the corresponding target residual capacity on a target curve according to the current voltage; in the process of charging and discharging events, monitoring charging and discharging current of a battery in the equipment in real time, and integrating the charging and discharging current with time to obtain the electric quantity variation of the battery in the equipment; and determining the real-time residual capacity of the battery in the device in the process of the charging and discharging event according to the sum of the target residual capacity and the electric quantity variation. By the method and the device, the residual electric quantity of the battery in the equipment can be displayed more accurately.
Description
Technical Field
The invention relates to the technical field of battery energy metering, in particular to a lithium battery electric quantity metering management system and an electric quantity metering management method.
Background
Lithium batteries are widely used in various electronic products such as mobile phones, computers, and various internet of things devices, and therefore, it is necessary to precisely measure the state of charge of each battery.
At present, the capacity measurement of a mobile phone battery is that an electric quantity measurement chip is connected in series on a protection circuit of the battery, wherein an integrated resistor is connected in series, and the resistance value is generally 20-30 milliohms. The basic principle is that a sampling resistor is integrated on the chip, when different currents flow, different pressure differences are generated, and the chip integrates the voltage (actually converted into current) and time to obtain the correct electric quantity when a user uses the electric quantity. And determining the coulomb meter reading between the discharge cut-off voltage and the charge cut-off voltage of the lithium battery according to the discharge cut-off voltage and the charge cut-off voltage, and obtaining more accurate battery electric quantity data. The prior art patent application CN200810170273.5 discloses a method for estimating the remaining battery power. The method comprises the following steps: measuring a current value, a voltage value and a temperature of the battery; correcting the current value based on the voltage value; calculating a current integration value by integrating the corrected current value, and calculating a current integration amount from the calculated current integration value by reflecting the charge/discharge efficiency; determining a battery forward voltage level from the measured current value, voltage value, and temperature, and determining whether it is necessary to correct the current integration level based on the forward voltage level; if it is determined that correction is not necessary, converting the current integration electric quantity into a residual electric quantity; and if it is determined that the correction is necessary, correcting the current integration amount of electricity and converting the corrected current integration amount of electricity into a remaining amount of electricity. By this method, the SOC of the battery can be calculated more accurately.
In the prior art, the residual capacity of one battery is evaluated to be accumulated with data of a plurality of charge-discharge cycles, but if a new battery is replaced, the residual capacity of the new battery can be obtained only by repeated learning and measurement of an electric quantity metering chip, and the process is long, so that the technical problem that the accurate metering of the residual capacity of the new battery is long in the prior art exists.
Disclosure of Invention
The invention aims to solve the technical problem of providing a lithium battery electricity metering management system and an electricity metering management method so as to shorten the accurate metering realization process of the residual electricity of a new battery.
The invention solves the technical problems through the following technical scheme:
the invention provides a lithium battery electric quantity metering management method, which comprises the following steps:
continuously acquiring the current voltage of a battery in the equipment, and judging whether voltage abrupt change exists between the current voltage and the last voltage;
if yes, judging that the equipment replaces a new battery, determining the residual capacity corresponding to the voltage at the current moment based on the voltage-residual capacity relation of the old battery, and taking the residual capacity as the current residual capacity of the new battery at the current moment;
continuously monitoring the discharge amount of the new battery in each period in the working process, the starting point voltage corresponding to the starting point of each period and the end point voltage corresponding to the end point by using a coulometer; fitting a first voltage-discharge curve by taking the voltage variation of the end point voltage relative to the start point voltage as a vertical axis and the accumulated discharge as a horizontal axis;
and comparing the similarity between the first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one, taking the residual electric quantity estimation parameter corresponding to the second voltage-discharge curve with the maximum similarity as a first target parameter, initializing an electric quantity metering chip of the equipment by using the first target parameter, and updating the current residual electric quantity.
Optionally, the determining whether a voltage jump exists between the current voltage and the previous voltage includes:
continuously acquiring a voltage sampling signal of a battery in the equipment, and screening out a target signal with the voltage and electricity larger than a first preset threshold value according to the voltage sampling signal;
acquiring a time stamp corresponding to each target signal, and taking the target signal corresponding to the time stamp nearest to the current moment as the last voltage; and acquiring whether the difference value between the current voltage and the last voltage is larger than a second preset threshold value, and if so, judging that the voltage mutation exists.
Optionally, the determining of the period includes:
and determining the period according to the discharge power, the discharge frequency, the discharge voltage and the corresponding weight relation of the new battery.
Optionally, the determining the period according to the discharge power, the discharge frequency, the discharge voltage and the corresponding weight relation of the new battery includes:
calculating a period according to the discharge power, the discharge frequency, the discharge voltage and the corresponding weight relation of the new battery by using a formula, t=a1+a1+a2+m2+a3, wherein,
t is a period; a1 is the weight corresponding to the discharge power; m1 is a normalized value of the discharge power of the new battery; a2 is the weight corresponding to the discharge frequency; m2 is a normalized value corresponding to the discharge frequency; a3 is the weight corresponding to the discharge voltage; m3 is a normalized value of the new battery discharge voltage.
Optionally, the comparing the similarity between the first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one includes:
acquiring a plurality of second voltage-discharge curves built in an electric quantity metering chip of a new battery;
and comparing the similarity of the first voltage-discharge curve with the similarity of the second voltage-discharge curve one by one.
Optionally, the method further comprises:
judging whether the similarity between the first voltage-discharge curve and the second voltage-discharge curve is smaller than a third preset threshold value;
if yes, the first voltage-discharge curve is sent to the metering server, so that the metering server compares the similarity between the first voltage-discharge curve and a third voltage-discharge curve stored in the metering server, and takes a residual electric quantity estimation parameter corresponding to the third voltage-discharge curve with the maximum similarity as a second target parameter, and an electric quantity metering chip of the second target parameter device is used.
Optionally, the comparing the similarity between the first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one includes:
extracting characteristic points on a first voltage-discharge curve to obtain a first characteristic point sequence, wherein the characteristic points comprise: one or a combination of inflection points and points with a tangential slope greater than the set slope;
randomly cutting the second voltage-discharge curve into a plurality of curve segments equal to the first voltage-discharge curve for each second voltage-discharge curve, extracting characteristic points on the curve segments and a second characteristic point sequence;
and respectively aligning the first characteristic point sequence and the second characteristic point sequence, and then calculating the shape similarity of the first voltage-discharge curve and the second voltage-discharge curve based on Euclidean distance between the characteristic points in the same sequence order.
Optionally, the comparing the similarity between the first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one includes:
sampling the first voltage-discharge curve to obtain a first sampling point; randomly cutting a second voltage-discharge curve into a plurality of curve segments equal to the first voltage-discharge curve for each second voltage-discharge curve, and extracting second sampling points on the curve segments;
the voltage is taken as an ordinate, the discharge capacity is taken as an abscissa, a voltage-discharge capacity coordinate system is constructed, corresponding starting point voltage and terminal point voltage are obtained for each first sampling point, and the first sampling points are mapped to first midpoints corresponding to the starting point voltage and the terminal point voltage;
for each second sampling point, acquiring corresponding starting point voltage and terminal point voltage, and mapping the second sampling points to second midpoints corresponding to the starting point voltage and the terminal point voltage;
by means of the formula (i),calculating a similarity between the first voltage-discharge curve and the second voltage-discharge curve, wherein,
p is the similarity between the first voltage-discharge curve and the second voltage-discharge curve; p (P) n The similarity between the nth first sampling point and the nth second sampling point is obtained; n is the number of the first sampling points and is equal to the number of the second sampling points; a is that Kn The K-th evaluation characteristic value is the nth first sampling point; a is that kn The kth evaluation characteristic value is the nth second sampling point; sigma is a sum function.
The invention also provides a lithium battery electric quantity metering management method which is applied to the server and comprises the following steps:
receiving a first voltage-discharge curve from a coulometric chip performing the method as described above; performing similarity comparison between the first voltage-discharge curve and a third voltage-discharge curve stored in the metering server;
and sending the residual electric quantity estimation parameter corresponding to the third voltage-discharge quantity curve with the maximum similarity as a second target parameter to an electric quantity metering chip of the new battery, and using the electric quantity metering chip of the second target parameter device.
The invention also provides a lithium battery electric quantity metering management system, which comprises:
a power metering chip for performing the method of any one of the above claims;
a server performing the method as described above.
Compared with the prior art, the invention has the following advantages:
the invention comprehensively considers the influences of the current load current, the cell voltage, the ambient temperature, the cell impedance, the cell aging and the like of the battery on the battery in the charging or discharging process by combining the coulomb integration and the voltage differentiation, uses the integral quantity to update the residual capacity of the battery pack in real time, and simultaneously updates, calculates and adjusts the capacity of the battery and accurately displays the residual electric quantity of the cell according to the measured relevant data such as the current, the voltage, the temperature and the like when the conditions are satisfied in the charging and discharging states.
Drawings
Fig. 1 is a schematic flow chart of a method for managing electric quantity measurement of a lithium battery according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of another method for managing electric quantity measurement of a lithium battery according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a first method of similar comparison in the lithium battery electric quantity measurement management method according to the embodiment of the present invention;
fig. 4 is a schematic diagram of a second method of similar comparison in the lithium battery electric quantity metering management method according to the embodiment of the present invention.
Detailed Description
The following describes in detail the examples of the present invention, which are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of protection of the present invention is not limited to the following examples.
Example 1
Fig. 1 is a schematic flow chart of a method for metering and managing electric quantity of a lithium battery according to an embodiment of the present invention, as shown in fig. 1, the method includes:
s001: carrying out continuous voltage measurement, residual capacity measurement and corresponding temperatures on the charge and discharge processes of the battery in the equipment in advance to obtain voltage measurement curves at all temperatures; the voltage measurement curve is discretized into several parts, and each discrete point is calibrated by using the residual capacity.
Illustratively, the battery measurement is performed before the battery is installed in the device only, and specifically, the measurement mode is:
at the temperature T1, discharging the battery in the device from the highest cut-off voltage to the lowest cut-off voltage, and continuously measuring the voltage and the residual capacity of the battery in the discharging process; obtaining a corresponding voltage measurement curve Q1; charging the battery in the device from the lowest cut-off voltage to the highest cut-off voltage, and continuously measuring the voltage and the residual capacity of the battery in the charging process; obtaining a corresponding voltage measurement curve Q2;
similarly, at the temperature T2, discharging the battery in the device from the highest cut-off voltage to the lowest cut-off voltage, and continuously measuring the voltage and the residual capacity of the battery in the discharging process; obtaining a corresponding voltage measurement curve Q3; charging the battery in the device from the lowest cut-off voltage to the highest cut-off voltage, and continuously measuring the voltage and the residual capacity of the battery in the charging process; obtaining a corresponding voltage measurement curve Q4;
similarly, at the temperature T3, discharging the battery in the device from the highest cut-off voltage to the lowest cut-off voltage, and continuously measuring the voltage and the residual capacity of the battery in the discharging process; obtaining a corresponding voltage measurement curve Q5; charging the battery in the device from the lowest cut-off voltage to the highest cut-off voltage, and continuously measuring the voltage and the residual capacity of the battery in the charging process; obtaining a corresponding voltage measurement curve Q6;
and so on, several voltage measurement curves Q1, Q2, Q3, qn are obtained.
And then, performing discretization processing on each voltage measurement curve in a working voltage range, such as a 1000mAh battery, calibrating the capacity of a battery core in a 50 mAh-1000 mAh interval (namely 5% -100%), taking a voltage V1 corresponding to 50mAh as a starting point, taking a voltage V2 corresponding to 1000mAh as an end point, dividing the voltage range between V1 and V2 into a plurality of parts, such as 1000 or 10000 equal parts, wherein each equal part corresponds to one discrete point, and calibrating the corresponding residual capacity for each discrete point. In general, the more and more precisely the number of fractions.
Further, as the number of discharge times of the lithium battery increases and the calendar life is consumed, the aging state and the impedance state of the lithium battery are continuously changed, and in the embodiment of the present invention, the step S001 of the embodiment of the present invention may be periodically performed after the battery is mounted inside the device, so as to be capable of adapting to the above change, and further objectively evaluate the relationship between the voltage and the capacity of the lithium battery.
S002: when a charging and discharging event occurs to the battery in the equipment, acquiring the current temperature of the battery in the equipment, and acquiring a matched target curve from each voltage test curve according to the current temperature; measuring the current voltage of the battery in the device at the current moment, and finding out the corresponding target residual capacity on the target curve according to the current voltage.
For example, if the current temperature is T1 and a discharge behavior occurs at this time, the found target curve is Q1; measuring the current voltage at the current time t1 to be V T1 The corresponding residual capacity is Q T1 ，
S003: in the process of charging and discharging events, monitoring charging and discharging current of a battery in the equipment in real time, and integrating the charging and discharging current with time to obtain the electric quantity variation of the battery in the equipment; and determining the real-time residual capacity of the battery in the device in the process of the charging and discharging event according to the sum of the target residual capacity and the electric quantity variation.
And at a time t2 in the process of the charge and discharge event, integrating the current between the current time t1 and the time t2 to obtain the battery discharge quantity delta Q between the current time t1 and the time t 2. According to the residual capacity Q corresponding to the current time t1 T1 Subtracting the battery discharge amount delta Q to obtain the residual capacity Q at the time t2 T2 The residual capacity Q T2 Dividing the discharge capacity of the lithium battery to obtain corresponding capacity percentage for display.
It should be emphasized that the discharge capacity of the lithium battery is the capacity data that the lithium battery can release in the process from the lowest cut-off voltage to the highest cut-off voltage of the lithium battery at the current temperature T1.
Example 2
In order to clearly and completely describe the embodiment of the present invention, before describing the embodiment of the present invention, an application scenario of the present invention is described. One or more lithium batteries are arranged in modern electronic products such as mobile phones, tablet personal computers and wearable electronic equipment, and can be ternary lithium batteries or polymer lithium batteries generally. For example, when the voltage of the battery reaches the minimum cut-off voltage, the battery can not discharge outwards, and the residual capacity of the battery is zero; when the battery is charged, the voltage of the battery is continuously increased, and when the voltage is increased to the highest cut-off voltage, the battery cannot be continuously charged any more, and the residual capacity of the battery is 100%. And a metering algorithm is arranged in an electric quantity metering chip in the equipment main board, and the metering algorithm learns and calculates the residual electric quantity according to a coulombmeter and a voltage sampling result of the battery in a complete charge-discharge cycle of the battery, so that the more accurate residual electric quantity is obtained.
The equipment is internally provided with a polymer lithium battery, the lithium battery stores electric energy, and the electric quantity in the lithium battery is continuously consumed when the equipment works. As the output voltage of the lithium battery is continuously reduced due to the consumption of electric power, a user needs to perform a charging operation on the lithium battery after the voltage is reduced to a certain extent. Repeatedly, the service life of the lithium battery is continuously reduced, and after the service life of the lithium battery is reduced to a certain degree, a user needs to replace the lithium battery. However, the object for learning the electric quantity metering chip in the main board of the device is always a lithium battery with an expired service life, various parameters in the electric quantity metering chip are matched with the lithium battery before replacement, and the physical and chemical state of the new battery is completely different from that of the lithium battery before replacement. A longer time is required for a complete charge-discharge cycle of the battery, so how to make the electric quantity metering chip in the device main board perform more accurate residual electric quantity evaluation in the shortest time after a new lithium battery is replaced, for example, when a complete charge-discharge cycle is not performed, such as after a new battery is replaced, and in the charging process is not performed yet, is a technical problem to be solved.
Based on this, on the basis of embodiment 1 of the present invention, fig. 2 is a flow chart of a method for metering and managing electric quantity of a lithium battery according to an embodiment of the present invention, as shown in fig. 2, where the method includes:
s101: and continuously acquiring the current voltage of the battery in the equipment, judging whether voltage abrupt change exists between the current voltage and the last voltage, and if so, executing the step S102.
The sampling chip on the battery protection plate may sample the output voltage of the battery in the device periodically or in real time, for example. It is understood that reference herein to a battery refers to a battery that is mounted within the device, including but not limited to a battery before replacement and a new battery after replacement.
When sampling the output voltage of the lithium battery, synchronously acquiring time stamps corresponding to sampling moments, and sequencing each voltage sampling signal according to the time stamps to obtain a voltage sampling signal sequence:
V1、V2、V3、V4、V5、....、Vn。
the state between the battery before replacement and the new battery after replacement is greatly different, so that the output voltages of the battery before replacement and the new battery after replacement are also greatly different; and no voltage sampling signal exists in the battery replacement process, so that the last voltage sampling signal before the blank period belongs to the voltage sampling signal of the battery before the replacement, and the first voltage sampling signal after the blank period belongs to the voltage sampling signal of the new battery.
And then, calculating a voltage difference value between two adjacent voltage sampling signals, judging whether the voltage difference value is larger than a second preset threshold value, if so, judging that voltage mutation exists, and judging that a user replaces a new battery.
Further, since a certain charge residue exists in the elements such as the capacitor and the inductor in the device circuit during the battery replacement, a weak voltage may be detected, and in order to avoid this situation, only the voltage sampling signal with a voltage value greater than the first preset threshold, for example, 3.0V, is processed in this step.
S102: if the determination result in step S101 is yes, it is determined that the device replaces the new battery, and based on the voltage-remaining capacity relationship of the old battery, the remaining capacity corresponding to the voltage at the current time is determined, and the remaining capacity is taken as the current remaining capacity of the new battery at the current time.
For example, since the new battery is just installed, the device cannot learn the power of the new battery, and therefore, the determination of the remaining power of the new battery can be roughly performed according to the voltage-remaining power relationship of the old battery before replacement, which specifically includes:
and measuring the voltage of the new battery at the current moment, inputting the current voltage at the current moment into a voltage-residual capacity relation model of the old battery, obtaining the residual capacity of the new battery, and displaying the residual capacity to a user.
Of course, the remaining power is not accurate enough, and subsequent calibration is performed in step S103 of the embodiment of the present invention.
S103: continuously monitoring the discharge amount of the new battery in each period in the working process, the starting point voltage corresponding to the starting point of each period and the end point voltage corresponding to the end point by using a coulometer; fitting a first voltage-discharge curve by taking the voltage variation of the end point voltage relative to the start point voltage as a vertical axis and the accumulated discharge as a horizontal axis;
in this step, first, according to the discharge power, discharge frequency, discharge voltage and corresponding weight relation of the new battery, a period is calculated by using a formula, t=a1×m1+a2×m2+a3×m3, wherein,
t is the calculated period; a1 is the weight corresponding to the discharge power; m1 is a normalized value of the discharge power of the new battery, and when the discharge power is normalized, the denominator can use the maximum value of the discharge power monitored in the calendar life of the old battery; a2 is the weight corresponding to the discharge frequency, and the discharge frequency can be the number of discharge pulses with the discharge power exceeding the set power; m2 is a normalized value corresponding to the discharge frequency; a3 is the weight corresponding to the discharge voltage; m3 is a normalized value of the new battery discharge voltage, and the maximum value of the discharge voltage monitored during the calendar life of the old battery can be used when normalization is performed.
Then, counting starting point voltage corresponding to the starting point and end point voltage corresponding to the end point of each period; and fitting a first voltage-discharge curve by taking the voltage variation of the end point voltage relative to the start point voltage as a vertical axis and taking the accumulated discharge quantity of the battery in the current charge-discharge cycle as a horizontal axis.
S104: and comparing the similarity between the first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one, taking the residual electric quantity estimation parameter corresponding to the second voltage-discharge curve with the maximum similarity as a first target parameter, initializing an electric quantity metering chip of the equipment by using the first target parameter, and updating the current residual electric quantity.
Illustratively, there are two ways of similarity comparison in this step, the first one being relatively coarse but the fastest and the second one being relatively precise but relatively computationally intensive. The similarity comparison mode can be selected according to specific requirements of engineering practice.
In a first aspect, fig. 3 is a schematic diagram of a first method for performing similarity comparison in a lithium battery electric quantity metering management method according to an embodiment of the present invention, and as shown in fig. 2, the step of performing similarity comparison on a first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one may include the following steps:
S104A: extracting characteristic points on a first voltage-discharge curve to obtain a first characteristic point sequence, wherein the characteristic points comprise: one or a combination of inflection points and points with a tangential slope greater than the set slope;
the first feature point sequence comprises the following feature points: d1, D2, D3, dn.
S104B: randomly cutting the second voltage-discharge curve into curve segments with m equal length to the first voltage-discharge curve according to each second voltage-discharge curve, extracting characteristic points on the curve segments and a second characteristic point sequence;
the 1 st second feature point sequence contains feature points as follows: d11, d12, d13, d1n.
The 2 nd second feature point sequence contains feature points as follows: d21, d22, d23, d2n.
…
The m second feature point sequence comprises the following feature points: dm1, dm2, dm3, dmn.
S104C: and respectively aligning the first characteristic point sequence and the second characteristic point sequence, and then calculating the shape similarity of the first voltage-discharge curve and the second voltage-discharge curve based on Euclidean distance between the characteristic points in the same sequence order.
Aligning the D1, D2, D3 and Dn with the first and last positions of D11, D12, D13 and D1n, calculating the Euclidean distance between D2 and D12, calculating the Euclidean distance between D3 and D13, and calculating the Euclidean distance between Dn and D1n.
In a second aspect, fig. 4 is a schematic diagram of a second method for performing similarity comparison in the lithium battery electric quantity metering management method according to the embodiment of the present invention, and as shown in fig. 4, the step of performing similarity comparison on a first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one may include the following steps:
S104D: sampling the first voltage-discharge curve to obtain a first sampling point; and randomly cutting the second voltage-discharge curve into a plurality of curve segments equal to the first voltage-discharge curve according to each second voltage-discharge curve, and extracting second sampling points on the curve segments.
The content of the step S104D is the same as that of the step S104A, S B.
S104E: and constructing a voltage-discharge capacity coordinate system by taking the voltage as an ordinate and the discharge capacity as an abscissa, acquiring a corresponding starting voltage V1 and an end voltage V2 for each first sampling point, and calculating a voltage midpoint V0 between the starting voltage V1 and the end voltage V2. And mapping the first sampling point onto a voltage midpoint V0, wherein the ordinate of the mapped point is V0, and the abscissa is the corresponding accumulated discharge amount.
S104F: and acquiring corresponding starting point voltage and end point voltage for each second sampling point, and mapping the second sampling points to second midpoints corresponding to the starting point voltage and the end point voltage.
The content of this step is the same as that of step S104E, and the embodiment of the present invention will not be described here again.
S104G: and acquiring characteristic values corresponding to each point, such as voltage and current, and the slope of the corresponding point on the first voltage-discharge curve and the slope of the corresponding point on the second voltage-discharge curve, according to each first sampling point and each second sampling point obtained after mapping.
For example, the 1 st first sampling point may be D1 (V1, I1, F1)
The nth first sampling point may be Dn (Vn, in, fn);
similarly, the number of the devices to be used in the system,
for example, the 1 st first sampling point may be d1 (v 1, i1, f 1)
The nth first sampling point may be dn (vn, in, fn);
firstly, calculating Euclidean distance between a first sampling point and a first second sampling point one by one, then, calculating Euclidean distance between a second first sampling point and a second sampling point, and so on to obtain Euclidean distance from each first sampling point to the second sampling point, and summing the Euclidean distances to obtain similarity between a first voltage-discharge curve and a plurality of preset second voltage-discharge curves, wherein the similarity is specifically as follows:
by means of the formula (i),calculating a similarity between the first voltage-discharge curve and the second voltage-discharge curve, wherein,
p is the similarity between the first voltage-discharge curve and the second voltage-discharge curve; p (P) n The similarity between the nth first sampling point and the nth second sampling point is obtained; n is the number of the first sampling points and is equal to the number of the second sampling points; a is that Kn The K-th evaluation characteristic value is the nth first sampling point; a is that kn The kth evaluation characteristic value is the nth second sampling point; sigma is a sum function. By applying the embodiment of the invention, more refined similarity comparison can be performed.
Then, a residual electric quantity estimation parameter corresponding to a second voltage-discharge quantity curve with the maximum similarity is used as a first target parameter, an electric quantity metering chip of the equipment is initialized by using the first target parameter, and the current residual electric quantity is updated.
According to the invention, through similarity comparison between voltage-discharge quantity curves, a first target parameter with a relatively close discharge characteristic is determined, and the electric quantity metering chip of the equipment is initialized by using the first target parameter, the inventor finds that the change trend of different types of batteries is different because the continuous increase of the discharge quantity can bring about voltage change, so that the estimated parameter corresponding to the relatively similar curve is screened out from the preset second voltage-discharge quantity curve to serve as the first target parameter, and compared with the estimated parameter of the battery before replacement in the prior art, the estimated parameter is closer to the actual condition of a new battery, and the method can be realized without complete charge-discharge cycle, and the speed is relatively high.
Example 3
Example 3 of the present invention is based on example 2 with the following steps added.
After the similarity is obtained, judging whether the similarity between the first voltage-discharge curve and the second voltage-discharge curve is smaller than a third preset threshold value;
if yes, the first voltage-discharge curve is sent to the metering server, so that the metering server compares the similarity between the first voltage-discharge curve and a third voltage-discharge curve stored in the metering server, and takes a residual electric quantity estimation parameter corresponding to the third voltage-discharge curve with the maximum similarity as a second target parameter, and an electric quantity metering chip of the second target parameter device is used.
It can be understood that the process of similarity comparison between the first voltage-discharge curve and the third voltage-discharge curve stored in the metering server by the metering server is the same as the process of comparison between the electric quantity metering chips in the device, and the difference is that the comparison object is the first voltage-discharge curve and the third voltage-discharge curve stored in the metering server, and the third voltage-discharge curve is online data, and the number is more, and the specific similarity comparison process is not repeated here in the embodiment of the invention.
Because the quantity of the second voltage-discharge quantity curves in the electric quantity metering chip of the equipment is limited, a result which is better matched with the first voltage-discharge quantity curves is difficult to obtain, and therefore, the first voltage-discharge quantity curves can be sent to a metering server to be matched on the server, further, a more accurate result is obtained, and quick and accurate metering of the residual electric quantity is realized.
Example 4
Corresponding to embodiment 3 of the present invention, embodiment 4 of the present invention provides a lithium battery electricity metering management method, applied to a server, the method comprising:
receiving a first voltage-discharge curve from a coulometric chip performing the method of example 3; performing similarity comparison between the first voltage-discharge curve and a third voltage-discharge curve stored in the metering server;
and sending the residual electric quantity estimation parameter corresponding to the third voltage-discharge quantity curve with the maximum similarity as a second target parameter to an electric quantity metering chip of the new battery, and using the electric quantity metering chip of the second target parameter device.
Example 5
Corresponding to embodiment 3 or embodiment 4 of the present invention, embodiment 5 of the present invention provides a lithium battery electricity metering management system, the system comprising:
a coulometric chip for performing the method of example 3;
a server performing the method of embodiment 4.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (11)
1. The lithium battery electricity metering management method is characterized by comprising the following steps:
carrying out continuous voltage measurement, residual capacity measurement and corresponding temperatures on the charge and discharge processes of the battery in the equipment in advance to obtain voltage measurement curves at all temperatures; dispersing the voltage measurement curve into a plurality of parts, and calibrating each discrete point by using the residual capacity;
when a charging and discharging event occurs to the battery in the equipment, acquiring the current temperature of the battery in the equipment, and acquiring a matched target curve from each voltage test curve according to the current temperature; measuring the current voltage of a battery in the equipment at the current moment, and finding out the corresponding target residual capacity on the target curve according to the current voltage;
in the process of charging and discharging events, monitoring charging and discharging current of a battery in the equipment in real time, and integrating the charging and discharging current with time to obtain the electric quantity variation of the battery in the equipment; and determining the real-time residual capacity of the battery in the device in the process of the charging and discharging event according to the sum of the target residual capacity and the electric quantity variation.
2. The lithium battery power metering management method of claim 1, further comprising:
continuously acquiring the current voltage of a battery in the equipment, and judging whether voltage abrupt change exists between the current voltage and the last voltage;
if yes, judging that the equipment replaces a new battery, determining the residual capacity corresponding to the voltage at the current moment based on the voltage-residual capacity relation of the old battery, and taking the residual capacity as the current residual capacity of the new battery at the current moment;
continuously monitoring the discharge amount of the new battery in each period in the working process, the starting point voltage corresponding to the starting point of each period and the end point voltage corresponding to the end point by using a coulometer; fitting a first voltage-discharge curve by taking the voltage variation of the end point voltage relative to the start point voltage as a vertical axis and the accumulated discharge as a horizontal axis;
and comparing the similarity between the first voltage-discharge curve and a plurality of preset second voltage-discharge curves one by one, taking the residual electric quantity estimation parameter corresponding to the second voltage-discharge curve with the maximum similarity as a first target parameter, initializing an electric quantity metering chip of the equipment by using the first target parameter, and updating the current residual electric quantity.
3. The method for managing power metering of a lithium battery according to claim 1, wherein the determining whether a voltage jump exists between a current voltage and a previous voltage comprises:
continuously acquiring a voltage sampling signal of a battery in the equipment, and screening out a target signal with the voltage and electricity larger than a first preset threshold value according to the voltage sampling signal;
acquiring a time stamp corresponding to each target signal, and taking the target signal corresponding to the time stamp nearest to the current moment as the last voltage; and acquiring whether the difference value between the current voltage and the last voltage is larger than a second preset threshold value, and if so, judging that the voltage mutation exists.
4. The lithium battery power metering management method according to claim 1, wherein the period determination process includes:
and determining the period according to the discharge power, the discharge frequency, the discharge voltage and the corresponding weight relation of the new battery.
5. The method according to claim 4, wherein determining the period according to the discharge power, the discharge frequency, the discharge voltage, and the corresponding weight relation of the new battery comprises:
calculating a period according to the discharge power, the discharge frequency, the discharge voltage and the corresponding weight relation of the new battery by using a formula, t=a1+a1+a2+m2+a3, wherein,
t is a period; a1 is the weight corresponding to the discharge power; m1 is a normalized value of the discharge power of the new battery; a2 is the weight corresponding to the discharge frequency; m2 is a normalized value corresponding to the discharge frequency; a3 is the weight corresponding to the discharge voltage; m3 is a normalized value of the new battery discharge voltage.
6. The method for managing electric quantity metering of lithium battery according to claim 1, wherein the step of comparing the similarity between the first voltage-discharge curve and the preset second voltage-discharge curves one by one comprises:
acquiring a plurality of second voltage-discharge curves built in an electric quantity metering chip of a new battery;
and comparing the similarity of the first voltage-discharge curve with the similarity of the second voltage-discharge curve one by one.
7. The lithium battery power metering management method of claim 6, further comprising:
judging whether the similarity between the first voltage-discharge curve and the second voltage-discharge curve is smaller than a third preset threshold value;
if yes, the first voltage-discharge curve is sent to the metering server, so that the metering server compares the similarity between the first voltage-discharge curve and a third voltage-discharge curve stored in the metering server, and takes a residual electric quantity estimation parameter corresponding to the third voltage-discharge curve with the maximum similarity as a second target parameter, and an electric quantity metering chip of the second target parameter device is used.
8. The method for managing electric quantity metering of lithium battery according to claim 1, wherein the step of comparing the similarity between the first voltage-discharge curve and the preset second voltage-discharge curves one by one comprises:
extracting characteristic points on a first voltage-discharge curve to obtain a first characteristic point sequence, wherein the characteristic points comprise: one or a combination of inflection points and points with a tangential slope greater than the set slope;
randomly cutting the second voltage-discharge curve into a plurality of curve segments equal to the first voltage-discharge curve for each second voltage-discharge curve, extracting characteristic points on the curve segments and a second characteristic point sequence;
and respectively aligning the first characteristic point sequence and the second characteristic point sequence, and then calculating the shape similarity of the first voltage-discharge curve and the second voltage-discharge curve based on Euclidean distance between the characteristic points in the same sequence order.
9. The method for managing electric quantity metering of lithium battery according to claim 1, wherein the step of comparing the similarity between the first voltage-discharge curve and the preset second voltage-discharge curves one by one comprises:
sampling the first voltage-discharge curve to obtain a first sampling point; randomly cutting a second voltage-discharge curve into a plurality of curve segments equal to the first voltage-discharge curve for each second voltage-discharge curve, and extracting second sampling points on the curve segments;
the voltage is taken as an ordinate, the discharge capacity is taken as an abscissa, a voltage-discharge capacity coordinate system is constructed, corresponding starting point voltage and terminal point voltage are obtained for each first sampling point, and the first sampling points are mapped to first midpoints corresponding to the starting point voltage and the terminal point voltage;
for each second sampling point, acquiring corresponding starting point voltage and terminal point voltage, and mapping the second sampling points to second midpoints corresponding to the starting point voltage and the terminal point voltage;
by means of the formula (i),and->Calculating a similarity between the first voltage-discharge curve and the second voltage-discharge curve, wherein,
p is the similarity between the first voltage-discharge curve and the second voltage-discharge curve; p (P) n The similarity between the nth first sampling point and the nth second sampling point is obtained; n is the number of the first sampling points and is equal to the number of the second sampling points; a is that Kn The K-th evaluation characteristic value is the nth first sampling point; a is that kn The kth evaluation characteristic value is the nth second sampling point; sigma is a sum function.
10. The lithium battery electricity metering management method is characterized by being applied to a server, and comprises the following steps:
receiving a first voltage-discharge curve from a coulometric chip performing the method of claim 5; performing similarity comparison between the first voltage-discharge curve and a third voltage-discharge curve stored in the metering server;
and sending the residual electric quantity estimation parameter corresponding to the third voltage-discharge quantity curve with the maximum similarity as a second target parameter to an electric quantity metering chip of the new battery, and using the electric quantity metering chip of the second target parameter device.
11. Lithium battery electricity metering management system, characterized in that it comprises:
a coulometric chip for performing the method of any one of claims 1-9;
a server performing the method of claim 10.
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