CN114069077B - Electrochemical device management method, electronic apparatus, and battery system - Google Patents
Electrochemical device management method, electronic apparatus, and battery system Download PDFInfo
- Publication number
- CN114069077B CN114069077B CN202111389709.1A CN202111389709A CN114069077B CN 114069077 B CN114069077 B CN 114069077B CN 202111389709 A CN202111389709 A CN 202111389709A CN 114069077 B CN114069077 B CN 114069077B
- Authority
- CN
- China
- Prior art keywords
- lithium
- soc
- internal resistance
- electrochemical device
- precipitation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000007726 management method Methods 0.000 title claims abstract description 21
- 238000001556 precipitation Methods 0.000 claims abstract description 195
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 156
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 155
- 238000007600 charging Methods 0.000 claims abstract description 130
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 48
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 37
- 206010011906 Death Diseases 0.000 claims abstract description 16
- 230000009467 reduction Effects 0.000 claims description 91
- 230000032683 aging Effects 0.000 claims description 35
- 230000004044 response Effects 0.000 claims description 28
- 238000004458 analytical method Methods 0.000 claims description 20
- 230000007423 decrease Effects 0.000 claims description 18
- 238000007405 data analysis Methods 0.000 claims description 16
- 230000001419 dependent effect Effects 0.000 claims description 12
- 238000012886 linear function Methods 0.000 claims description 12
- 230000006870 function Effects 0.000 description 62
- 230000008859 change Effects 0.000 description 15
- 230000008569 process Effects 0.000 description 11
- 238000012360 testing method Methods 0.000 description 9
- 230000008021 deposition Effects 0.000 description 7
- 125000004122 cyclic group Chemical group 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000002159 abnormal effect Effects 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000010828 elution Methods 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007635 classification algorithm Methods 0.000 description 2
- 238000004590 computer program Methods 0.000 description 2
- 238000010280 constant potential charging Methods 0.000 description 2
- 238000010277 constant-current charging Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 239000007784 solid electrolyte Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
Abstract
The embodiment of the application provides an electrochemical device management method, electronic equipment and a battery system. The method comprises the following steps: performing an intermittent charging operation on the electrochemical device, acquiring data related to the electrochemical device in the intermittent charging operation, and determining a lithium-out SOC and a reference internal resistance of the electrochemical device based on the data related to the electrochemical device; based on the lithium-ion SOC and the reference internal resistance, a target lithium-ion SOC and a target internal resistance are determined. Responding to the target lithium precipitation SOC and the target internal resistance to be in a lithium precipitation value area of the electrochemical device; it is determined that the electrochemical device enters an end-of-life EOL state. Because the lithium precipitation SOC and the internal resistance of the electrochemical device and the relation between the lithium precipitation SOC and the internal resistance of the electrochemical device are considered when determining whether the electrochemical device enters the end-of-life EOL state, the EOL state of the electrochemical device is comprehensively judged, the possibility of misjudgment is reduced, and the judgment accuracy is improved.
Description
Technical Field
The present application relates to the field of electrochemical technologies, and in particular, to an electrochemical device management method, an electronic device, and a battery system.
Background
The lithium ion battery has the advantages of large specific energy density, long cycle life, high nominal voltage, low self-discharge rate, small volume, light weight and the like, and has wide application in the consumer electronics field.
With the high-speed development of tablet computers, mobile phones and electric vehicles in recent years, and due to the continuous development of new energy industries, the market demand for lithium ion batteries is also increasing. The lithium ion battery has a greater safety risk in the battery Life usage (EOL) state than in the initial use. In the prior art, whether the electrochemical device enters the EOL state is generally judged according to the number of charge-discharge cycles or the capacity retention rate, the judgment index is single, and the influence of lithium analysis on the aging of the lithium ion battery is ignored, so that the EOL state of the electrochemical device is not accurately judged. Therefore, how to accurately determine the state of the electrochemical device to enter EOL becomes a urgent problem to be solved.
Disclosure of Invention
An object of the embodiments of the present application is to provide an electrochemical device management method, an electronic apparatus, and a battery system, so as to improve the safety of an electrochemical device during use.
According to an aspect of an embodiment of the present application, there is provided an electrochemical device management method including: performing an intermittent charging operation on an electrochemical device, acquiring data related to the electrochemical device in the intermittent charging operation, and determining a lithium-out SOC and a reference internal resistance of the electrochemical device based on the data related to the electrochemical device, the reference internal resistance being used to indicate the internal resistance of the electrochemical device when charged to a first SOC; determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance; and determining an end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being in a region of the electrochemical device where lithium-out occurs or a region of the electrochemical device where aging occurs. When determining the EOL state of the end-of-life of the electrochemical device, considering whether the target lithium precipitation SOC and the target internal resistance of the electrochemical device are in a lithium precipitation region of the electrochemical device or an aging region of the electrochemical device, namely, considering the lithium precipitation SOC and the internal resistance of the electrochemical device and the relation between the lithium precipitation SOC and the internal resistance of the electrochemical device, comprehensively judging the EOL state of the electrochemical device, reducing the possibility of misjudgment and improving the judgment accuracy.
In one embodiment of the present application, the lithium deposition region of the electrochemical device includes a first deposition region and a second deposition region. The first value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a first lithium-precipitation degree; the second value region is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a second lithium-precipitation degree before the first lithium-precipitation degree. The determining an end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being at a region of the electrochemical device where lithium-out occurs or a region of the electrochemical device where aging occurs, comprising: reducing a charging current of the electrochemical device by a first current reduction step and/or reducing a charge cutoff voltage of the electrochemical device by a first voltage reduction step in response to the target lithium-ion SOC and the target internal resistance being in the first value region; or in response to the target lithium-out SOC and the target internal resistance being in the second value region, reducing the charging current of the electrochemical device by a second current reduction, the second current reduction being less than the first current reduction, and/or reducing the charge cutoff voltage of the electrochemical device by a second voltage reduction, the second voltage reduction being less than the first voltage reduction; or in response to the target lithium precipitation SOC and the target internal resistance being in a value region where aging of the electrochemical device occurs, reducing a charging current of the electrochemical device by a third current reduction, and/or reducing a charging cutoff voltage of the electrochemical device by a third voltage reduction, the third current reduction being smaller than the first current reduction, the third voltage reduction being smaller than the first voltage reduction. Since the charging current and the charging cut-off voltage of the electrochemical device are reduced, it is possible to avoid the safety problem caused in the continued use.
In another implementation of the present application, the first value region includes a region where the reference internal resistance and the lithium-precipitation SOC satisfy a first value condition. Wherein, the first value condition includes: the reference internal resistance is less than or equal to the first internal resistance threshold and the lithium-eluting SOC is less than or equal to the smaller of the lithium-eluting SOC threshold and the function value of the first function. The first function includes a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative first slope that characterizes a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a first lithium-eluting level.
In another implementation of the present application, the second value region includes a region where the reference internal resistance and the lithium-ion precipitation SOC satisfy a second value condition. Wherein the second value condition includes: the reference internal resistance is greater than a second internal resistance threshold and less than or equal to the first internal resistance threshold, and the lithium-precipitation SOC is greater than a function value of a first function, less than a smaller one of the lithium-precipitation SOC threshold and a function value of a second function; or the reference internal resistance is larger than the first internal resistance threshold and smaller than or equal to a third internal resistance threshold, and the lithium-precipitation SOC is smaller than the function value of the second function. The second function includes a linear function having a reference internal resistance as an independent variable, a lithium-eluting SOC as a dependent variable, and a negative second slope characterizing a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a second lithium-eluting level, the first internal resistance threshold being greater than the second internal resistance threshold and less than the third internal resistance threshold.
In another embodiment of the present application, the region of the electrochemical device where aging occurs includes a region where the reference internal resistance and the lithium SOC satisfy a third value condition. The third value condition comprises that the reference internal resistance is larger than the third internal resistance threshold value and the lithium-precipitation SOC is smaller than the lithium-precipitation SOC threshold value.
In another implementation of the present application, the determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance includes: taking the lithium-precipitation SOC as the target lithium-precipitation SOC; and taking the reference internal resistance as the target internal resistance. In this way, the target lithium-ion SOC and the target internal resistance are calculated in a simple manner, thereby simplifying the calculation process of the EOL state of the electrochemical device.
In another implementation of the present application, the method further includes: at least one historical lithium-ion SOC of the electrochemical device and at least one historical reference internal resistance of the electrochemical device are obtained. The determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance includes: taking the weighted average of the lithium-precipitation SOC and the at least one historical lithium-precipitation SOC as the target lithium-precipitation SOC; and taking a weighted average of the reference internal resistance and the at least one historical reference internal resistance as the target internal resistance. Since at least one lithium-out SOC and at least one reference internal resistance of the electrochemical device are also taken into consideration in determining the target lithium-out SOC and the target internal resistance, a subsequent erroneous judgment of the electrochemical device entering the EOL state can be prevented, and the accuracy of the judgment can be improved.
In another embodiment of the present application, the data related to the electrochemical device includes an SOC of the electrochemical device and an internal resistance of the electrochemical device, the intermittent charging operation includes a plurality of charging periods and a plurality of intermittent periods, and the determining the lithium-out SOC of the electrochemical device and the reference internal resistance based on the data related to the electrochemical device includes: acquiring an internal resistance and an SOC of the sample electrochemical device during the interval; obtaining a first curve based on the SOC and the internal resistance during each break, the first curve representing a variation of the internal resistance with the SOC; the lithium-ion SOC is determined based on the first curve, and the reference internal resistance is determined based on the first curve.
In another implementation of the present application, the determining the lithium-eluting SOC includes at least one of pattern A1 and pattern A2 based on the first curve. Wherein, the mode A1 includes: differentiating the first curve to obtain a first differential curve; determining whether the first differential curve has a maximum value and a minimum value; and if the maximum value and the minimum value exist, determining the SOC corresponding to the maximum value as the lithium-precipitation SOC. The mode A2 includes: differentiating the first curve to obtain a first differential curve; differentiating the first differential curve to obtain a second differential curve; and determining the SOC corresponding to the point where the ordinate of the second differential curve appears smaller than zero for the first time as the lithium precipitation SOC.
According to yet another aspect of embodiments of the present application, there is provided a battery system comprising a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor, when executing the machine-executable instructions, implementing the method of any of the preceding method embodiments.
According to still another aspect of the embodiments of the present application, there is provided an electronic device, where the electronic device includes the battery system described in the foregoing embodiments.
According to still another aspect of the embodiment of the present application, there is provided an electronic device, including: data analysis means, target data determination means, and protection means. The data analysis device is used for carrying out intermittent charging operation on the electrochemical device, acquiring data related to the electrochemical device in the intermittent charging operation, and determining lithium precipitation SOC (state of charge) and reference internal resistance of the electrochemical device based on the data related to the electrochemical device, wherein the reference internal resistance is used for indicating the internal resistance when the electrochemical device is charged to a first SOC. The target data determining means is configured to determine a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance. And the protection device is used for determining the EOL state of the electrochemical device at the end of life of the electrochemical device in response to the target lithium precipitation SOC and the target internal resistance being in a lithium precipitation value area of the electrochemical device or an aging value area of the electrochemical device. When determining the EOL state of the end-of-life of the electrochemical device, considering whether the target lithium precipitation SOC and the target internal resistance of the electrochemical device are in a lithium precipitation region of the electrochemical device or an aging region of the electrochemical device, namely, considering the lithium precipitation SOC and the internal resistance of the electrochemical device and the relation between the lithium precipitation SOC and the internal resistance of the electrochemical device, comprehensively judging the EOL state of the electrochemical device, reducing the possibility of misjudgment and improving the judgment accuracy.
In one embodiment of the present application, the lithium deposition region of the electrochemical device includes a first deposition region and a second deposition region. The first value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a first lithium-precipitation degree; the second value region is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a second lithium-precipitation degree before the first lithium-precipitation degree. The protection device is specifically used for: reducing a charging current of the electrochemical device by a first current reduction step and/or reducing a charge cutoff voltage of the electrochemical device by a first voltage reduction step in response to the target lithium-ion SOC and the target internal resistance being in the first value region; or in response to the target lithium-ion SOC and the target internal resistance being in the second value region, reducing the charging current of the electrochemical device by a second current reduction, the second current reduction being less than the first current reduction, and/or reducing the charge cutoff voltage of the electrochemical device by a second voltage reduction, the second voltage reduction being less than the first voltage reduction; or in response to the target lithium precipitation SOC and the target internal resistance being in a value region where aging of the electrochemical device occurs, reducing the charging current of the electrochemical device by a third current reduction, and/or reducing the charging cut-off voltage of the electrochemical device by a third voltage reduction, the third current reduction being smaller than the first current reduction, the third voltage reduction being smaller than the first voltage reduction. Since the charging current and the charging cutoff voltage of the electrochemical device are reduced, safety problems caused during the subsequent use can be avoided.
In one embodiment of the present application, the first value region includes a region in which the reference internal resistance and the lithium-ion-precipitating SOC satisfy a first value condition. Wherein, the first value condition includes: the reference internal resistance is less than or equal to the first internal resistance threshold and the lithium-eluting SOC is less than or equal to the smaller of the lithium-eluting SOC threshold and the function value of the first function. The first function includes a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative first slope that characterizes a maximum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a first lithium-eluting level.
In one embodiment of the present application, the second value region includes a region in which the reference internal resistance and the lithium-ion-precipitating SOC satisfy a second value condition. Wherein the second value condition includes: the reference internal resistance is greater than a second internal resistance threshold and less than or equal to the first internal resistance threshold, and the lithium-precipitation SOC is greater than a function value of a first function, less than a smaller one of the lithium-precipitation SOC threshold and a function value of a second function; or the reference internal resistance is greater than the first internal resistance threshold and less than or equal to a third internal resistance threshold, and the lithium-precipitating SOC is less than a function value of the second function. The second function includes a linear function having a reference internal resistance as an independent variable, a lithium-eluting SOC as a dependent variable, and a negative second slope characterizing a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a second lithium-eluting level, the first internal resistance threshold being greater than the second internal resistance threshold and less than the third internal resistance threshold.
In one embodiment of the present application, the region of the electrochemical device where aging occurs includes a region where the reference internal resistance and the lithium SOC satisfy a third value condition; the third value condition comprises that the reference internal resistance is larger than the third internal resistance threshold value and the lithium-precipitation SOC is smaller than the lithium-precipitation SOC threshold value.
In one embodiment of the present application, the target data determining device is specifically configured to: taking the lithium-precipitation SOC as the target lithium-precipitation SOC; and taking the reference internal resistance as the target internal resistance. Thus, the target lithium-ion SOC and the target internal resistance are calculated in a simple manner, thereby simplifying the calculation process of the EOL state of the electrochemical device.
In one embodiment of the application, the electronic device further comprises a historical lithium analysis data acquisition means for acquiring at least one historical lithium analysis SOC of the electrochemical device and at least one historical reference internal resistance of the electrochemical device. The target data determining device is specifically configured to: taking a weighted average of the lithium-out SOC and the at least one historical lithium-out SOC as the target lithium-out SOC; and taking a weighted average of the reference internal resistance and the at least one historical reference internal resistance as the target internal resistance. Since at least one lithium-out SOC and at least one reference internal resistance of the electrochemical device are also taken into consideration when determining the target lithium-out SOC and the target internal resistance, a subsequent erroneous judgment of the electrochemical device entering the EOL state can be prevented, and the accuracy of the judgment can be improved.
In one embodiment of the present application, the data related to the electrochemical device includes an SOC of the electrochemical device and an internal resistance of the electrochemical device, and the intermittent charging operation includes a plurality of charging periods and a plurality of intermittent periods. The data analysis device is specifically used for: acquiring an internal resistance and an SOC of the electrochemical device during the interruption; obtaining a first curve based on the SOC and the internal resistance during each break, the first curve representing a variation of the internal resistance with the SOC; the lithium-ion SOC is determined based on the first curve, and the reference internal resistance is determined based on the first curve.
In one embodiment of the present application, the data analysis device is specifically configured to: at least one of the modes A1 and A2 is performed. Wherein, the mode A1 includes: differentiating the first curve to obtain a first differential curve; determining whether the first differential curve has a maximum value and a minimum value; and if the maximum value and the minimum value exist, determining the SOC corresponding to the maximum value as the lithium-precipitation SOC. The mode A2 includes: differentiating the first curve to obtain a first differential curve; differentiating the first differential curve to obtain a second differential curve; and determining the SOC corresponding to the point where the ordinate of the second differential curve appears smaller than zero for the first time as the lithium precipitation SOC.
According to the electrochemical device management method, the electronic equipment and the battery system, the EOL state of the electrochemical device is determined by acquiring the lithium-out SOC and the reference internal resistance of the electrochemical device, determining the target lithium-out SOC of the electrochemical device and the target internal resistance of the electrochemical device based on the lithium-out SOC and the reference internal resistance of the electrochemical device, and further determining the EOL state of the electrochemical device by responding to the fact that the values of the target lithium-out SOC of the electrochemical device and the target internal resistance of the electrochemical device are in the value area where lithium-out of the electrochemical device occurs or the value area where aging of the electrochemical device occurs. When determining whether the electrochemical device enters the end-of-life EOL state, considering whether the target lithium precipitation SOC and the target internal resistance of the electrochemical device are in a lithium precipitation region of the electrochemical device or an aging region of the electrochemical device, namely, considering the lithium precipitation SOC and the internal resistance of the electrochemical device and the relation between the lithium precipitation SOC and the internal resistance of the electrochemical device, comprehensively judging the EOL state of the electrochemical device, reducing the possibility of misjudgment and improving the judgment accuracy.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments described in the embodiments of the present application, and other drawings may be obtained according to these drawings for a person having ordinary skill in the art.
Fig. 1 is a flowchart illustrating steps of a method for managing an electrochemical device according to an embodiment of the present application;
FIG. 2 is an exemplary flow chart of step 110 according to an embodiment of the application;
FIG. 3 is a flowchart illustrating steps of another method for managing an electrochemical device according to an embodiment of the present application;
FIG. 4 is a flowchart illustrating steps of another method for managing an electrochemical device according to an embodiment of the present application;
Fig. 5 is a schematic view of a region where lithium precipitation occurs in an electrochemical device and a region where aging occurs in the electrochemical device according to an embodiment of the present application;
FIG. 6 is a flowchart illustrating steps of another method for managing an electrochemical device according to an embodiment of the present application;
fig. 7 is a flowchart showing steps of another method for managing an electrochemical device.
FIG. 8 is a schematic diagram illustrating the division of a first value region and a second value region according to an embodiment of the present application;
Fig. 9 is a block diagram of an electronic device according to an embodiment of the present application;
fig. 10 is a block diagram of a charging device according to an embodiment of the present application; and
Fig. 11 is a block diagram of a battery system according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions, and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings and examples. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other technical solutions obtained by a person skilled in the art based on the embodiments of the present application fall within the scope of protection of the present application.
The embodiment of the present application will be described with reference to the drawings.
In the context of the embodiments of the present application, the present application is exemplified by a lithium ion battery as an example of an electrochemical device, but the electrochemical device of the present disclosure is not limited to only a lithium ion battery.
The embodiment of the application provides an electrochemical device management method, and an execution subject of the method can be a Battery management system (Battery MANAGEMENT SYSTEM, BMS). As shown in fig. 1, the method comprises the steps of:
Step 110: an intermittent charging operation is performed on an electrochemical device, data related to the electrochemical device is acquired in the intermittent charging operation, and a lithium-out State of Charge (SOC) and a reference internal resistance of the electrochemical device are determined based on the data related to the electrochemical device.
Wherein the reference internal resistance is used to indicate a corresponding one of the internal resistance values when the electrochemical device is charged to the first SOC during the intermittent charging. For example, the first SOC may be 50%. It should be understood that the first SOC may be any value between 40% and 70% as the first SOC, which is not limited in this embodiment.
In the embodiment of the present application, the lithium-eluting SOC may refer to an SOC related to a lithium-eluting state of an electrochemical device. The smaller the lithium-eluting SOC, the more serious the lithium-eluting state.
In the embodiment of the present application, the intermittent charging operation may refer to a process of performing the intermittent charging operation on the electrochemical device. Specifically, in one implementation, the intermittent charging operation includes a plurality of charging periods and a plurality of intermittent periods. Illustratively, charging the electrochemical device during a first charging period, then stopping the charging, and after a first intermittent period, continuing to charge the electrochemical device during a second charging period, and repeating this until the SOC of the electrochemical device reaches a first threshold. It can be understood that as intermittent charging proceeds, the SOC of the electrochemical device increases, and the embodiment of the present application may stop intermittent charging when the SOC of the electrochemical device reaches the first critical value, thereby completing the intermittent charging operation. The first critical value is not particularly limited in the present application, as long as the object of the present application can be achieved, and for example, the first critical value may be 60%, 70%, 80%, 90% or 100%. The charging mode in the intermittent charging operation is not particularly limited in the embodiment of the application, and the charging mode can be constant-voltage charging, constant-current and constant-voltage charging or segmented constant-current charging as long as the purpose of the embodiment of the application can be achieved.
In the embodiment of the present application, the data related to the electrochemical device may refer to data capable of reflecting the state of the electrochemical device, including, but not limited to, data of charging voltage, charging current, internal resistance, SOC, etc. of the electrochemical device.
Referring to fig. 2, in one implementation, step 110 includes:
Step 1101, obtaining an internal resistance and an SOC of the electrochemical device during the interruption.
In the embodiment of the present application, in the intermittent charging operation, the internal resistance of the electrochemical device may be determined based on the terminal voltage and the charging current of the electrochemical device detected during each of the discontinuities.
The determination of the internal resistance of the electrochemical device during the current interruption is described as an example. Specifically, a first terminal voltage of an electrochemical device at a start time point during the interruption and a second terminal voltage of the electrochemical device at an End time point during the interruption are acquired (for example, acquired through an Analog Front End (AFE) of the BMS), a voltage difference of the first terminal voltage and the second terminal voltage is determined, and an internal resistance of the electrochemical device is determined based on the voltage difference and a charging current of the electrochemical device detected during the charging.
In the embodiment of the present application, in the intermittent charging operation, the SOC of the electrochemical device may be determined based on a pre-stored voltage-SOC relationship table. For example, a voltage-SOC relation table in which SOCs of electrochemical devices corresponding to different terminal voltages, for example, 85% SOCs for 4.2V and 90% SOCs for 4.3V, may be stored in advance in the BMS. Thus, after the terminal voltage of the electrochemical device at the end time point of the current interruption period is acquired, the SOC of the electrochemical device can be determined based on the terminal voltage and the voltage-SOC relationship table. It is to be understood that the SOC of the electrochemical device may also be determined based on a terminal voltage and a voltage-SOC relationship table at a starting point of time of the current intermittent period of the electrochemical device, which is not limited in this embodiment.
Step 1102, obtaining a first curve based on the SOC and the internal resistance during each break.
In the embodiment of the application, after acquiring the SOC and the internal resistance of the electrochemical device in each intermittent period, a plurality of data pairs consisting of the SOC and the internal resistance can be obtained, the SOC of the electrochemical device can be taken as an abscissa, the internal resistance of the electrochemical device can be taken as an ordinate, points represented by the data pairs are filled in a coordinate system, a first curve is obtained after fitting, and the first curve represents the change of the internal resistance of the electrochemical device along with the SOC.
It can be understood that the more densely the SOC and internal resistance data of the electrochemical device are collected, the more data pairs are obtained, and a finer first curve can be obtained. The process of curve fitting using the data is well known to those skilled in the art, and the comparison of the present application is not particularly limited.
Step 1103, determining a lithium-ion SOC based on the first curve, and determining a reference internal resistance based on the first curve.
In the embodiment of the present application, since the first curve represents the change of the internal resistance with the SOC, determining the reference internal resistance based on the first curve may include: the target point when the SOC is the first SOC is determined on the first curve, and the internal resistance value of the target point is used as the reference internal resistance, so that the reference internal resistance can be accurately determined by a simpler method. It should be appreciated that the reference internal resistance may be determined in any other suitable manner, which is not limited in this embodiment.
In embodiments of the present application, determining the lithium-ion SOC based on the first curve may be implemented in a variety of ways. The following is exemplified by two specific implementations.
In one specific implementation, the process of determining the lithium-ion SOC based on the first curve may be manner A1. Mode A1 includes:
and step A11, differentiating the first curve to obtain a first differential curve.
Since the first curve represents the change of the internal resistance R of the electrochemical device with the SOC of the electrochemical device, the first differential curve obtained by differentiating the first curve, that is, the first differential curve is a first-order differential curve of the first curve, which actually represents the rate of change of the internal resistance of the electrochemical device with the SOC.
Step A12, determining whether the first differential curve has a maximum value and a minimum value.
Mathematically, when the first differential curve has both maxima and minima, it is stated that the original flat region on the first differential curve exhibits a more pronounced undulating change, i.e., an abnormal decrease. In an embodiment of the present application, the first differential curve represents a rate of change of the internal resistance of the electrochemical device with the SOC. When no abnormal decrease in the rate of change occurs in the flat region of the curve, it indicates that the electrochemical device has no active lithium precipitated. When the change rate is abnormally reduced in the flat area of the curve, active lithium is precipitated on the surface of the negative electrode and contacts with the negative electrode, and the negative electrode graphite part is connected with a lithium metal device in parallel, so that the impedance of the whole negative electrode part is reduced, the internal resistance of the electrochemical device is abnormally reduced when active lithium is precipitated, and correspondingly, the flat area of the first differential curve is abnormally reduced.
And step A13, if the maximum value and the minimum value exist, determining the SOC corresponding to the maximum value as the lithium precipitation SOC.
When the maximum value and the minimum value exist, the lithium precipitation tendency or the lithium precipitation occurrence of the electrochemical device at the maximum value is indicated, the SOC corresponding to the maximum value is determined as the lithium precipitation SOC, so that the lithium precipitation SOC of the electrochemical device is reasonably determined, the electrochemical device is determined to enter an EOL state according to the lithium precipitation SOC, and the use safety of the electrochemical device is improved.
In this other specific implementation, the process of determining the lithium-ion SOC based on the first curve may be the mode A2. Mode A2 includes:
and step A21, differentiating the first curve to obtain a first differential curve.
The step a21 is the same as the step a11, and can be understood with reference to the step a11, and will not be described herein.
And step A22, differentiating the first differential curve to obtain a second differential curve.
Wherein the second differential curve can be understood as the second differential curve of the first curve
And A23, determining that the SOC corresponding to the point where the ordinate of the second differential curve is smaller than zero for the first time is the lithium precipitation SOC.
If the ordinate of the second differential curve is smaller than zero, determining the SOC corresponding to the point of the second differential curve, where the ordinate is smaller than zero for the first time, as the lithium precipitation SOC.
It should be understood that the above two specific implementations of determining lithium-eluting SOC are only alternative implementations and are not limiting of the inventive examples.
In an embodiment of the present application, step 110 may be performed by a data analysis device. The embodiment of the present application is not particularly limited to the data analysis device 1010 as long as intermittent charging operation can be achieved. For example, the data analysis device 1010 may be a controller unit (Microcontroller Unit, MCU) in a Battery management system (Battery MANAGEMENT SYSTEM, BMS). The operation of the process shown above is for illustrative purposes only.
Step 112, determining a target lithium-out SOC of the electrochemical device and a target internal resistance of the electrochemical device based on the lithium-out SOC and the reference internal resistance.
Wherein the target lithium-eluting SOC and the target internal resistance may be a lithium-eluting SOC and a reference internal resistance, respectively, used for determining whether the electrochemical device is in the EOL state.
To simplify the calculation process, in one implementation, step 112 may include: taking the lithium precipitation SOC of the electrochemical device as a target lithium precipitation SOC; the reference internal resistance of the electrochemical device is taken as a target internal resistance of the electrochemical device. That is, in the subsequent step, it is determined whether the electrochemical device enters the EOL state directly using the lithium-out SOC of the electrochemical device and the value of the reference internal resistance.
However, in order to prevent erroneous determination of the electrochemical device entering the EOL state, the accuracy of the determination is improved, and at least one lithium-out SOC and at least one reference internal resistance of the electrochemical device, that is, at least one historical lithium-out SOC and at least one historical reference internal resistance, may also be considered in determining whether the electrochemical device enters the EOL state.
Specifically, in another implementation, the electrochemical device management method may further include: at least one historical lithium-ion SOC of the electrochemical device and at least one historical reference internal resistance of the electrochemical device are obtained. Accordingly, as shown in fig. 3, step 112 may include:
112A, taking a weighted average value of the lithium-out SOC of the electrochemical device and at least one historical lithium-out SOC of the electrochemical device as a target lithium-out SOC of the electrochemical device; and
112B, taking a weighted average of the reference internal resistance of the electrochemical device and at least one historical reference internal resistance of the electrochemical device as a target internal resistance of the electrochemical device.
In this way, in the subsequent step, when judging whether the electrochemical device enters the EOL state, not only the lithium-out SOC and the reference internal resistance of the currently acquired electrochemical device but also at least one calendar Shi Xi lithium SOC and at least one historical reference internal resistance of the previously acquired electrochemical device are considered, so that erroneous judgment that the electrochemical device enters the EOL state due to errors in the lithium-out SOC and the reference internal resistance of the currently acquired electrochemical device is avoided, and the accuracy of judgment is improved.
It should be understood that when considering the previously acquired lithium-out SOC and the reference internal resistance of the electrochemical device, a two-dimensional map of the lithium-out SOC-internal resistance may also be drawn from the data pair consisting of the currently acquired lithium-out SOC and the reference internal resistance of the electrochemical device, and the previously acquired at least one data pair consisting of the historical lithium-out SOC and the at least one reference internal resistance of the at least one electrochemical device. That is, the two-dimensional map is drawn by filling the points represented by these data pairs in the coordinate system with the reference internal resistance as the abscissa and the lithium analysis SOC of the electrochemical device as the ordinate. In the subsequent step, whether the electrochemical device enters an EOL state or not is judged according to the value condition of each point in the two-dimensional graph.
And 114, determining the EOL state of the electrochemical device in response to the target lithium precipitation SOC and the target internal resistance being in a lithium precipitation region of the electrochemical device or an aging region of the electrochemical device.
In the embodiment of the application, the value area where lithium is precipitated in the electrochemical device may refer to a distribution area of data points formed by the lithium precipitation SOC and the reference internal resistance in a two-dimensional coordinate system with the reference internal resistance as an abscissa and the lithium precipitation SOC as an ordinate when lithium is precipitated in a certain degree in the electrochemical device. The value region where the electrochemical device is aged may refer to a distribution region of data points composed of the lithium-analysis SOC and the reference internal resistance in a two-dimensional coordinate system having the reference internal resistance as an abscissa and the lithium-analysis SOC as an ordinate when the electrochemical device is aged to some extent. During the charging process of the electrochemical device, when an abnormal situation occurs, part of lithium ions of the electrochemical device are precipitated on the surface of the negative electrode of the electrochemical device, and cannot be inserted into the negative electrode of the electrochemical device, i.e., lithium precipitation occurs in the electrochemical device. When lithium is extracted from an electrochemical device, the amount of lithium ions decreases due to the inability of some lithium ions to intercalate into the negative electrode of the electrochemical device, and thus the capacity of the electrochemical device is reduced, that is, the electrochemical device is aged. In addition, lithium ions deposited on the surface of the anode of the electrochemical device may penetrate the separator between the cathode and the anode of the electrochemical device, causing an internal short circuit of the electrochemical device, so that the electrochemical device presents a great safety risk. Therefore, when it is determined that the electrochemical device has some degree of lithium precipitation, it is considered that the electrochemical device enters the EOL state, and the use of the electrochemical device should be limited.
When the electrochemical device generates lithium precipitation to a certain extent, the values of the lithium precipitation SOC and the internal resistance are in the following distribution rule: the lithium-separating SOC is smaller, and the internal resistance is smaller, wherein the smaller the lithium-separating SOC is, the more serious the lithium-separating is. In addition, when lithium is evolved to some extent in the electrochemical device, the lithium-evolved SOC is relatively fast with respect to the change in internal resistance, i.e., the internal resistance is slowly increased, while the lithium-evolved SOC is rapidly decreased. Accordingly, the EOL state of the electrochemical device may be determined based on whether the target lithium-precipitation SOC of the electrochemical device and the target internal resistance of the electrochemical device are in the region where the lithium-precipitation of the electrochemical device occurs. The value area of the electrochemical device where lithium precipitation occurs can be obtained by performing a cyclic test on a sample of the electrochemical device under at least one operating condition in which lithium precipitation is likely to occur in the electrochemical device.
For example, lithium separation is likely to occur when an electrochemical device is operated at an ambient temperature of 10 ℃ or lower, and is unlikely to occur when it is operated at an ambient temperature of 20 ℃ or higher. When the value region of the electrochemical device where lithium precipitation occurs is obtained, charge-discharge cycle operation can be performed on a plurality of electrochemical device samples at a plurality of ambient temperatures above 20 ℃ and at a plurality of ambient temperatures below 10 ℃ respectively, wherein one electrochemical device sample corresponds to one ambient temperature. When the number of charge-discharge cycle operations reaches a preset number (for example, 100 times) for each electrochemical device sample, the lithium-analysis SOC and the reference internal resistance of the electrochemical device sample are obtained by the lithium-analysis detection analysis, and the above-described process is repeated until the capacity retention rate of the electrochemical device is less than a preset value (for example, 70%).
And performing curve fitting according to the plurality of lithium-precipitation SOCs and the plurality of reference internal resistances, which are acquired for each electrochemical device sample, so as to obtain a curve of the lithium-precipitation SOCs of the electrochemical device, which changes along with the reference internal resistances. The first boundary line between the former and latter curves is determined by a known classification algorithm based on the slopes of the plurality of curves obtained for the plurality of electrochemical device samples at a plurality of ambient temperatures above 20 ℃ and the slopes of the plurality of curves obtained for the plurality of electrochemical device samples at a plurality of ambient temperatures below 10 ℃. And determining a value area of the electrochemical device where lithium precipitation occurs according to the first dividing line and the distribution condition of the lithium precipitation SOC and the internal resistance of the electrochemical device. The slope of the curve, which may also be referred to as the rate of change of the curve, represents the rate of change of the lithium-ion-eluting SOC with the reference internal resistance, and may be obtained by differentiating the curve.
It is understood that the charge rate, the charge depth, etc. are also major factors affecting the occurrence of lithium precipitation in the electrochemical device. Therefore, the electrochemical device sample may be tested at a charging rate and/or a charging depth that easily cause lithium precipitation in the electrochemical device and at a charging rate and/or a charging depth that does not easily cause lithium precipitation in the electrochemical device, respectively, and the value region of the electrochemical device where lithium precipitation occurs may be determined based on the slopes of the plurality of curves obtained by the test in a similar manner to the test performed at different ambient temperatures.
In addition, during the use of the electrochemical device, a solid electrolyte interface (solid electrolyte interphase, SEI) film of the negative electrode of the electrochemical device may gradually grow, and a separator between the positive electrode and the negative electrode of the electrochemical device becomes thick, resulting in the diffusion of lithium ions being blocked, so that the electrochemical device charges slowly and capacity decays, i.e., the electrochemical device ages. When the electrochemical device is aged to some extent, the lithium-precipitation SOC is less varied, and the internal resistance is more varied. Namely, the values of the lithium precipitation SOC and the internal resistance have the following distribution rules: the lithium precipitation SOC is larger and the internal resistance is larger. The larger the lithium-eluting SOC, the less serious the lithium-eluting. Furthermore, the lithium-evolving SOC is relatively slow with respect to the change in internal resistance, i.e., the internal resistance increases rapidly, while the lithium-evolving SOC decreases slowly. Thus, the EOL state of the electrochemical device may be determined based on whether or not the values of the target lithium-ion SOC and the target internal resistance of the electrochemical device are in the value region where the aging of the electrochemical device occurs. The value area of the electrochemical device subjected to aging can be determined through a test according to the corresponding internal resistance and the distribution condition of the SOC when the electrochemical device sample subjected to lithium precipitation when the capacity of the electrochemical device sample is reduced to a preset value.
The region of the electrochemical device where lithium precipitation occurs and/or the region of the electrochemical device where aging occurs may be stored in advance in an internal memory device of the BMS of the electrochemical device or in other memory devices accessible to the BMS.
In the embodiment of the application, the target lithium-precipitation SOC of the electrochemical device and the target internal resistance of the electrochemical device are determined by acquiring the lithium-precipitation SOC of the electrochemical device and the reference internal resistance and based on the lithium-precipitation SOC of the electrochemical device and the reference internal resistance, and then the electrochemical device is determined to enter the EOL state by responding to the fact that the values of the target lithium-precipitation SOC of the electrochemical device and the target internal resistance of the electrochemical device are in the value region where lithium precipitation of the electrochemical device or the value region where aging of the electrochemical device occurs. When determining whether the electrochemical device enters the end-of-life EOL state, considering whether the target lithium precipitation SOC and the target internal resistance of the electrochemical device are in a lithium precipitation region of the electrochemical device or an aging region of the electrochemical device, namely considering the lithium precipitation SOC and the internal resistance of the electrochemical device and the relationship between the lithium precipitation SOC and the internal resistance of the electrochemical device, comprehensively judging the EOL state of the electrochemical device, reducing the possibility of misjudgment and improving the judgment accuracy.
As shown in fig. 4, in one embodiment of the present application, the value region where lithium precipitation occurs in the electrochemical device includes a first value region for indicating a value range of the lithium precipitation SOC and the reference internal resistance when the electrochemical device is at the first lithium precipitation level. Accordingly, determining that the electrochemical device enters an end-of-life EOL state in response to the target lithium-out SOC and the target internal resistance being at a region of the electrochemical device where lithium-out occurs or a region of the electrochemical device where aging occurs, comprising: step 114A, in response to the target lithium-out SOC and the target internal resistance being in the first value region, reducing the charging current of the electrochemical device by a first current reduction step, and reducing the charge cutoff voltage of the electrochemical device by a first voltage reduction step.
In the embodiment of the application, the first lithium precipitation degree may represent a severe lithium precipitation, that is, the first value region is a value range of the lithium precipitation SOC and the reference internal resistance when the electrochemical device is subjected to severe lithium precipitation.
The first range of values may be obtained by performing a cyclic test on at least one sample of the electrochemical device under at least one operating condition in which heavy lithium evolution is likely to occur in the electrochemical device and under at least one operating condition in which light lithium evolution is likely to occur in the electrochemical device, wherein one electrochemical device corresponds to one operating condition. For example, an electrochemical device is susceptible to severe lithium precipitation when operated at an ambient temperature of-10 ℃ or lower, and is susceptible to slight lithium precipitation when operated at an ambient temperature of 10 ℃ or lower and-5 ℃ or higher. In acquiring the first value region, the plurality of electrochemical device samples may be subjected to charge-discharge cycle operations at a plurality of ambient temperatures in a range of-10 ℃ to-15 ℃ and at a plurality of ambient temperatures of 10 ℃ or less and-5 ℃ or more, respectively. For each electrochemical device sample, when the number of charge-discharge cycle operations reaches a preset number (e.g., 100 times), the lithium-out SOC and the reference internal resistance of the electrochemical device sample are obtained by the lithium-out detection analysis, and the above-described process is repeated until the capacity retention rate of the electrochemical device is less than a preset value (e.g., 70%). And performing curve fitting according to a plurality of lithium-precipitation SOCs and a plurality of reference internal resistances of electrochemical device samples obtained for each electrochemical device to obtain a curve (namely a lithium-precipitation SOC-internal resistance curve) of the lithium-precipitation SOCs of the electrochemical device along with the change of the reference internal resistances.
Determining a second boundary line of the former plurality of curves and the latter plurality of curves by a known classification algorithm based on the slopes of the plurality of curves obtained for the plurality of electrochemical device samples at a plurality of ambient temperatures in the range of-10 ℃ to-15 ℃ and the slopes of the plurality of curves obtained for the plurality of electrochemical device samples at a plurality of ambient temperatures in the range of-5 ℃ to 10 ℃. The first value range is determined based on the second boundary line and the distribution of the lithium-ion separation SOC and the internal resistance of the electrochemical device. It is understood that the charge rate, the charge depth, etc. are also major factors affecting the occurrence of lithium precipitation in the electrochemical device. Therefore, the electrochemical device sample can be subjected to the cyclic test at the charging rate and/or the charging depth which easily cause the electrochemical device to generate serious lithium precipitation, so that the first value range is obtained.
Specifically, in one implementation, the first value region includes a region where the reference internal resistance and the lithium SOC satisfy a first value condition, the first value condition including: the reference internal resistance is less than or equal to the first internal resistance threshold, and the lithium-eluting SOC is less than or equal to the smaller of the lithium-eluting SOC threshold and the function value of the first function.
Wherein the first function comprises a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative first slope that characterizes a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a first lithium-eluting level.
Specifically, the first function is a functional representation of the second boundary line, and the slope of the first function is the slope of the second boundary line. The function value of the first function is the value of the lithium-precipitation SOC corresponding to the reference internal resistance when the reference internal resistance is known. As shown in fig. 8, a solid line 810 is a lithium-eluting SOC-internal resistance curve obtained at-10 ℃, and a solid line 830 is a lithium-eluting SOC-internal resistance curve obtained at 10 ℃, respectively located on both sides of a first function (i.e., a second boundary line), which is represented by a broken line 820.
And when the first internal resistance threshold is that the function value of the first function is 0, referencing the value of the internal resistance. That is, the first internal resistance threshold is determined by a first function.
The lithium-eluting SOC threshold is the minimum SOC at which lithium-eluting occurs in the electrochemical device. The lithium-deposition SOC threshold value may be set according to the SOC distribution at the time of occurrence of lithium deposition. For example, in the course of experiments on samples of electrochemical devices, when it is found that the samples of electrochemical devices have lithium precipitated, the SOC of the samples of electrochemical devices is mostly 50%, and then the lithium precipitation SOC threshold value may be determined to be slightly higher, so as to leave a certain margin, for example, the lithium precipitation SOC may be determined to be 60%.
In the embodiment of the present application, as shown in fig. 5, in a two-dimensional coordinate system with the reference internal resistance as the abscissa and the lithium-analysis SOC as the ordinate, the first value-taking region is represented by a region a surrounded by a broken line 501, a broken line 502, and the horizontal and vertical axes of the two-dimensional coordinate system. Wherein the dashed line 501 represents the first function and the dashed line 502 represents the lithium-precipitation SOC threshold.
In the embodiment of the application, when the target lithium-precipitation SOC and the target internal resistance of the electrochemical device are in the first value region, the serious lithium precipitation of the electrochemical device is determined. In order to avoid safety problems during continued use, the charging current and the charging cut-off voltage of the electrochemical device may be greatly reduced. For example, the charging current of the electrochemical device is reduced by a first current reduction, and the charge cutoff voltage of the electrochemical device is reduced by a first voltage reduction. The charging current may refer to a current used during charging of the electrochemical device. The charge cutoff voltage may refer to a voltage at which the electrochemical device reaches a full charge state during charging of the electrochemical device.
In an embodiment of the application, the first current drop amplitude may be 10% of the nominal charging current. For example, the nominal charging current of the electrochemical device is 3A, and the first current step-down may be 0.3A. It should be appreciated that the first current step-down may be any value within a range of 8% -12% of the nominal charging current, which is not limited in this embodiment of the present application.
In an embodiment of the present application, the first voltage drop may be 4% of the nominal charge cutoff voltage. For example, the nominal charging voltage of the electrochemical device is 4.2V, and the first voltage drop is 0.168V. It should be understood that the first voltage drop may be any value within a range of 2% -6% of the nominal charging voltage, which is not limited in the embodiment of the present application.
In another embodiment of the present application, as shown in fig. 6, the region of the electrochemical device where lithium precipitation occurs further includes a second region of values indicating a range of values of the lithium-precipitating SOC and the reference internal resistance when the electrochemical device is at a second lithium-precipitating level that is prior to the first lithium-precipitating level. That is, the second lithium precipitation level is less than the first lithium precipitation level.
Accordingly, determining an end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being at a region of the electrochemical device where lithium-out occurs or a region of the electrochemical device where aging occurs, comprising: step 114B, in response to the target lithium-ion SOC and the target internal resistance of the electrochemical device being in the second value region, reducing the charging current of the electrochemical device by a second current reduction, and reducing the charge cutoff voltage of the electrochemical device by a second voltage reduction, the second current reduction being less than the first current reduction, the second voltage reduction being less than the first voltage reduction.
The second lithium-separating degree is smaller than the first lithium-separating degree, which can indicate that the first electrochemical device slightly separates lithium, that is, the second value area is the value range of the lithium-separating SOC and the reference internal resistance when the electrochemical device slightly separates lithium. The second region is obtained by cyclic testing in a manner substantially similar to the first region under at least one operating condition in which slight lithium precipitation of the electrochemical device is likely to occur, at least one operating condition in which severe lithium precipitation of the electrochemical device is likely to occur, and at least one operating condition in which lithium precipitation of the electrochemical device is unlikely to occur.
Specifically, the first boundary line is determined based on a curve obtained by performing a test under at least one operation condition in which the electrochemical device is liable to slightly precipitate lithium and at least one operation condition in which the electrochemical device is not liable to precipitate lithium. The first dividing line may be represented by a second function, which is represented in fig. 8 as a dashed line 840. Furthermore, as previously mentioned, a second boundary line is determined based on a curve obtained by testing under at least one operating condition in which slight lithium precipitation is likely to occur in the electrochemical device, and at least one operating condition in which severe lithium precipitation is likely to occur in the electrochemical device, the second boundary line being represented by a first function, which is represented as a dotted line 820 in fig. 8. A second region of value is determined based on the region between the first boundary and the second boundary. As shown in fig. 8, a solid line 810 is a lithium-eluting SOC-internal resistance curve obtained at-10 ℃ and represents a case where serious lithium elution occurs in an electrochemical device. The solid line 850 is a lithium-eluting SOC-internal resistance curve obtained at 25 ℃, and represents a case where lithium elution does not easily occur or does not occur in the electrochemical device. The solid line 830 is a lithium-eluting SOC-internal resistance curve obtained at 10 c, representing the case where slight lithium elution occurs in the electrochemical device. The solid line 830 is located between the first dividing line 840 and the second dividing line 820.
Specifically, in one implementation, the second value-taking region includes a region where the reference internal resistance and the lithium SOC satisfy the second value-taking condition, and the second value-taking condition includes: the reference internal resistance is greater than the second internal resistance threshold and less than or equal to the first internal resistance threshold, the lithium-eluting SOC is greater than the function value of the first function, and less than the lesser of the lithium-eluting SOC threshold and the function value of the second function. The second function comprises a linear function taking the reference internal resistance as an independent variable and the lithium precipitation SOC as a dependent variable and having a negative second slope, wherein the second slope represents a minimum rate of decrease of the lithium precipitation SOC along with the reference internal resistance when the electrochemical device is at a second lithium precipitation level, and the first internal resistance threshold is greater than the second internal resistance threshold and less than the third internal resistance threshold.
The second internal resistance threshold is a reference internal resistance when the function value of the first function is the first SOC threshold, that is, the second internal resistance threshold is set according to the first SOC threshold and the first function.
When slight lithium precipitation occurs in the electrochemical device instead of severe lithium precipitation, the lithium precipitation SOC of the electrochemical device is greater than the function value of the first function and less than the smaller of the lithium precipitation SOC threshold value and the function value of the second function. Meanwhile, when slight lithium precipitation occurs in an electrochemical device, the lithium precipitation SOC is relatively large even though there is overlap of the reference internal resistance with that when serious lithium precipitation occurs in the electrochemical device. By determining whether or not the target internal resistance and the reference internal resistance of the electrochemical device satisfy these conditions, it can be determined that slight lithium precipitation of the electrochemical device occurs.
In addition, the second value condition may further include: the reference internal resistance is greater than the first internal resistance threshold and less than or equal to the third internal resistance threshold, and the lithium-ion separation SOC is less than the function value of the second function.
Wherein the third internal resistance threshold is used for indicating the minimum internal resistance when serious aging of the electrochemical device occurs. The third internal resistance threshold value may be set according to the corresponding internal resistance when the capacity of the electrochemical device decreases to a certain degree (e.g., 80%). Specifically, the capacity of the electrochemical device decreases as the number of charge and discharge cycles increases during use of the electrochemical device. Meanwhile, as the number of charge and discharge cycles increases, the internal resistance of the electrochemical device increases, so that a certain correspondence exists between the capacity of the electrochemical device and the internal resistance of the electrochemical device. Accordingly, the electrochemical device is considered to be aged when the capacity of the electrochemical device is reduced to a certain extent, and the third internal resistance threshold value may be set according to the internal resistance corresponding to the reduction of the capacity of the electrochemical device to a certain extent, such that when the internal resistance of the electrochemical device is greater than the third internal resistance threshold value, it is determined that the capacity of the electrochemical device is severely aged.
When the electrochemical device is slightly precipitated, but not severely aged, the lithium precipitation SOC of the electrochemical device is smaller than a preset SOC threshold value or a function value of the second function, but the reference internal resistance has not yet reached the third internal resistance threshold value. By determining whether or not the target internal resistance and the reference internal resistance of the electrochemical device satisfy these conditions, it can be determined that slight lithium precipitation of the electrochemical device occurs.
With continued reference to fig. 5, in a two-dimensional coordinate system having the reference internal resistance as the abscissa and the lithium analysis SOC as the ordinate, the second value region is represented by a region B surrounded by a broken line 501, a broken line 502, a broken line 503, a broken line 504, and the abscissa of the coordinate system. Wherein the dashed line 503 represents the second function and the value on the horizontal axis corresponding to the dashed line 504 represents the third internal resistance threshold.
In the embodiment of the application, when the target lithium-precipitation SOC of the electrochemical device and the target internal resistance of the electrochemical device are in the second value region, it is determined that slight lithium precipitation of the electrochemical device occurs. Considering that the electrochemical device is slightly eluted with lithium, the possibility of causing a safety problem is relatively small, and the charging current and the charging voltage can be reduced relatively little. For example, the charging current of the electrochemical device is reduced by a second current reduction, which is less than the first current reduction, and the charging cutoff voltage of the electrochemical device is reduced by a second voltage reduction, which is less than the first voltage reduction. Thereby ensuring a charging speed while improving the safety of the electrochemical device.
In an embodiment of the application, the second current step-down may be 5% of the nominal charging current. For example, the nominal charging current of the electrochemical device is 3A, and the first current step-down may be 0.15A. It should be appreciated that the second current step-down may be any value between 3% and 6% of the nominal charging current, which is not limited in this embodiment of the application.
In an embodiment of the present application, the second voltage drop may be 2% of the nominal charge cutoff voltage. For example, the nominal cutoff charging voltage of the electrochemical device is 4.2V, and the first voltage drop is 0.084V. It should be appreciated that the second voltage drop may also be any value between 1% and 3% of the nominal charging voltage, which is not limited in this embodiment of the application.
As shown in fig. 7, in another embodiment of the present application, the region of the electrochemical device where the aging occurs includes a region where the reference internal resistance and the lithium-analysis SOC satisfy a third value condition, the third value condition including the reference internal resistance being greater than a third internal resistance threshold value and the lithium-analysis SOC being less than a lithium-analysis SOC threshold value.
As mentioned previously, the third internal resistance threshold value is used to indicate the minimum internal resistance at which serious aging of the electrochemical device occurs. The third internal resistance threshold may be set according to the corresponding internal resistance when the capacity of the electrochemical device decreases to a certain extent (for example, 80%). When the electrochemical device is severely aged, the lithium-separating SOC is smaller than the lithium-separating SOC threshold, and the reference internal resistance is larger than the third internal resistance threshold, namely the reference internal resistance is larger. By determining whether or not the target internal resistance and the reference internal resistance of the electrochemical device satisfy these conditions, it can be determined that serious aging of the electrochemical device occurs.
With continued reference to fig. 5, in a two-dimensional coordinate system having the reference internal resistance as the abscissa and the lithium analysis SOC as the ordinate, the region where the electrochemical device is aged is indicated by a region C surrounded by a broken line 502, a broken line 504, and the abscissa of the coordinate system.
In the embodiment of the application, when the target lithium-ion SOC of the electrochemical device and the target internal resistance of the electrochemical device are in the value region where the electrochemical device is aged, it is determined that the electrochemical device is severely aged. Considering that the electrochemical device is severely aged, only the charging speed is slowed and the capacity of the electrochemical device is small, and the possibility of causing safety problems is relatively small, the charging current and the charging voltage can be reduced relatively little. Accordingly, determining the end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being at the value region of the electrochemical device where lithium-out occurs or the value region of the electrochemical device where aging occurs may include: step 114C, reducing the charging current of the electrochemical device by a third current reduction, and reducing the charging cutoff voltage of the electrochemical device by a third voltage reduction, the third current reduction being less than the first current reduction, the third voltage reduction being less than the first voltage reduction. Thereby ensuring a charging speed while improving the safety of the electrochemical device.
In one implementation of the application, the third voltage drop may be equal to the second voltage drop. The third current step-down may be equal to the second current step-down.
In particular, the third current drop amplitude may be 5% of the nominal charging current. For example, the nominal charging current of the electrochemical device is 3A, the first current step-down may be 0.15A. It should be appreciated that the third current step-down may be any value between 3% and 6% of the nominal charging current, which is not limited in this embodiment of the application.
Specifically, the third voltage drop may be 2% of the nominal charge cutoff voltage. For example, the nominal charging voltage of the electrochemical device is 4.2V, and the first voltage drop is 0.084V. It should be appreciated that the third voltage drop may also be any value between 1% and 3% of the nominal charging voltage, which is not limited in this embodiment of the application.
The embodiment of the application also provides an electronic device, as shown in fig. 9, the electronic device 900 includes a data analysis device 910, a target data determining device 912, and a protecting device 914.
The data analysis device 910 is used to perform an intermittent charging operation on the electrochemical device, acquire data related to the electrochemical device in the intermittent charging operation, and determine a lithium precipitation SOC and a reference internal resistance of the electrochemical device based on the data related to the electrochemical device. The reference internal resistance is used to indicate the internal resistance when the electrochemical device is charged to the first SOC.
The target data determination means 912 is for determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance.
The protection device 914 is configured to determine an end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being at a value region where lithium-out of the electrochemical device occurs or at a value region where aging of the electrochemical device occurs.
An electrochemical device may be included in the electronic apparatus of the embodiment of the present application. The electronic device may be, for example, a new energy vehicle, a mobile phone, a tablet computer, etc. with built-in lithium ion battery, a device with data processing capabilities. The embodiment of the present application is not particularly limited in the structures of the data analysis device 910, the target data determination device 912, and the protection device 914, as long as the corresponding functions can be realized.
In one implementation of the present application, the lithium-eluting region of the electrochemical device includes a first value region and a second value region; the first value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a first lithium-precipitation degree; the second value region is used for indicating a value range of the lithium-separating SOC and the reference internal resistance when the electrochemical device is at a second lithium-separating degree before the first lithium-separating degree.
The protection device 914 is specifically configured to: in response to the target lithium-out SOC and the target internal resistance being at the first value region, reducing the charging current of the electrochemical device by a first current reduction step, and/or reducing the charge cutoff voltage of the electrochemical device by a first voltage reduction step; or in response to the target lithium-ion SOC and the target internal resistance being in a second value region, reducing the charging current of the electrochemical device by a second current reduction, and/or reducing the charging cut-off voltage of the electrochemical device by a second voltage reduction, the second current reduction being less than the first current reduction, the second voltage reduction being less than the first voltage reduction; or in response to the target lithium precipitation SOC and the target internal resistance being in a value area where the electrochemical device is aged, reducing the charging current of the electrochemical device by a third current reduction, and/or reducing the charging cut-off voltage of the electrochemical device by a third voltage reduction, wherein the third current reduction is smaller than the first current reduction, and the third voltage reduction is smaller than the first voltage reduction.
In one implementation of the application, the first value region includes a region where the reference internal resistance and the lithium SOC satisfy the first value condition. The first value condition includes: the reference internal resistance is less than or equal to the first internal resistance threshold and the lithium-eluting SOC is less than or equal to the smaller of the lithium-eluting SOC threshold and the function value of the first function. The first function includes a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative first slope that characterizes a maximum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a first lithium-eluting level.
In one implementation of the application, the second value region includes a region where the reference internal resistance and the lithium SOC satisfy the second value condition. The second value condition includes: the reference internal resistance is larger than the second internal resistance threshold and smaller than or equal to the first internal resistance threshold, the lithium-precipitation SOC is larger than the function value of the first function, and smaller than the smaller of the lithium-precipitation SOC threshold and the function value of the second function; or the reference internal resistance is larger than the first internal resistance threshold and smaller than or equal to the third internal resistance threshold, and the lithium-precipitation SOC is smaller than the function value of the second function. The second function includes a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative second slope that characterizes a minimum rate of change of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a second lithium-eluting level, the first internal resistance threshold being greater than the second internal resistance threshold and less than the third internal resistance threshold.
In one implementation of the present application, the region of the electrochemical device where aging occurs includes a region where the reference internal resistance and the lithium-ion-precipitating SOC satisfy a third value-precipitating condition, the third value-precipitating condition including the reference internal resistance being greater than a third internal resistance threshold and the lithium-ion-precipitating SOC being less than a lithium-ion-precipitating SOC threshold.
In one implementation of the present application, the target data determining apparatus 912 is specifically configured to: taking the lithium precipitation SOC as a target lithium precipitation SOC; and taking the reference internal resistance as a target internal resistance.
In one implementation of the application, the electronic device further comprises a historical lithium analysis data acquisition means for acquiring at least one historical lithium analysis SOC of the electrochemical apparatus and at least one historical reference internal resistance of the electrochemical apparatus. Accordingly, the target data determining device 912 is specifically configured to: taking a weighted average of the lithium-precipitation SOC and at least one historical lithium-precipitation SOC as a target lithium-precipitation SOC; and taking a weighted average of the reference internal resistance and the at least one historical reference internal resistance as a target internal resistance.
In one implementation of the present application, the data related to the electrochemical device includes SOC of the electrochemical device and internal resistance of the electrochemical device, the intermittent charging operation includes a plurality of charging periods and a plurality of intermittent periods, and the data analysis device 910 is specifically configured to: acquiring an internal resistance and an SOC of the electrochemical device during the interruption; based on the SOC and the internal resistance in each intermittent period, a first curve is obtained, wherein the first curve represents the change of the internal resistance along with the SOC; based on the first curve, a lithium-ion SOC is determined, and based on the first curve, a reference internal resistance is determined.
In one implementation of the present application, the data analysis device 910 is specifically configured to: at least one of the modes A1 and A2 is performed. Wherein, mode A1 includes: differentiating the first curve to obtain a first differential curve; determining whether the first differential curve has a maximum value and a minimum value; and if the maximum value and the minimum value exist, determining the SOC corresponding to the maximum value as the lithium precipitation SOC. Mode A2 includes: differentiating the first curve to obtain a first differential curve; differentiating the first differential curve to obtain a second differential curve; and determining the SOC corresponding to the point where the ordinate of the second differential curve appears smaller than zero for the first time as the lithium precipitation SOC.
The electronic device in the embodiment of the application can be used for realizing the corresponding lithium precipitation detection method in the plurality of method embodiments, and has the beneficial effects of the corresponding method embodiments, and is not repeated herein. In addition, the functional implementation of each device in the electronic apparatus of this embodiment may refer to the description of the corresponding parts in the foregoing method embodiments, which is not repeated herein.
The embodiment of the application also provides a charging device, as shown in fig. 10, the charging device 1000 includes a processor 1001 and a processor 1002, and the charging device 1010 may further include a charging circuit module 1003, an interface 1004, a power interface 1005, and a rectifying circuit 1006. The charging circuit module 1003 is configured to perform intermittent charging operation on the lithium ion battery (i.e., the electrochemical device); the charging circuit module 1003 may also be configured to collect parameters such as terminal voltage and charging current of the lithium ion battery, and send the parameters to the processor; the interface 1004 is used for electrically connecting with the electrochemical device 2000; the power interface 1005 is used for connecting with an external power supply; the rectifying circuit 1006 is used for rectifying an input current; the processor 1002 stores machine executable instructions that are executable by the processor, and when executed by the processor 1001, implement the method steps described in any of the method embodiments above.
The embodiment of the application also provides a computer readable storage medium, and a computer program is stored in the computer readable storage medium, and when the computer program is executed by a processor, the method steps of any one of the method embodiments are realized.
The embodiment of the present application further provides a battery system, as shown in fig. 11, where the battery system 1100 includes a second processor 1101 and a second machine readable storage medium 1102, and the battery system 1100 may further include a charging circuit module 1103, a lithium ion battery 1104, and a second interface 1105. The charging circuit module 1103 is configured to perform intermittent charging operation on the lithium ion battery; the charging circuit module 1103 may also be configured to collect parameters such as terminal voltage and charging current of the lithium ion battery, and send these parameters to the second processor. The second interface 1105 is for interfacing with the external charger 1200; the external charger 1200 is used to supply power; the second machine-readable storage medium 1102 stores machine-executable instructions executable by the processor, which when executed by the second processor 1101, implement the method steps described in any of the method embodiments described above. The external charger 1200 may include a first processor 1201, a first machine-readable storage medium 1202, a first interface 1203, and corresponding rectifying circuitry, and may be a commercially available charger, and the structure of the external charger is not specifically limited in the embodiments of the present application.
The embodiment of the application also provides electronic equipment, which comprises the battery system.
The machine-readable storage medium may include random access memory (Random Access Memory, RAM) or non-volatile memory (non-volatile memory), such as at least one disk memory. Optionally, the memory may also be at least one memory device located remotely from the aforementioned processor.
The processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, abbreviated as CPU), a network processor (Network Processor, abbreviated as NP), etc.; but may also be a digital signal processor (DIGITAL SIGNAL Processing, DSP), application Specific Integrated Circuit (ASIC), field-Programmable gate array (FPGA) or other Programmable logic device, discrete gate or transistor logic device, discrete hardware components.
For the electronic device/charging apparatus/storage medium/battery system embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and reference is made to the description of the method embodiments for relevant points.
Claims (18)
1. An electrochemical device management method, wherein the method comprises:
performing an intermittent charging operation on an electrochemical device, acquiring data related to the electrochemical device in the intermittent charging operation, and determining a lithium-out SOC of the electrochemical device and a reference internal resistance based on the data related to the electrochemical device, wherein the reference internal resistance is used for indicating the internal resistance when the electrochemical device is charged to a first SOC, the lithium-out SOC refers to an SOC related to a lithium-out state of the electrochemical device, and the smaller the lithium-out SOC is, the more serious the lithium-out state is;
determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance;
determining an end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being at a region of the electrochemical device where lithium-out occurs or a region of the electrochemical device where aging occurs,
Wherein the data related to the electrochemical device includes an SOC of the electrochemical device and an internal resistance of the electrochemical device, the intermittent charging operation includes a plurality of charging periods and a plurality of intermittent periods, and the determining of the lithium-out SOC of the electrochemical device and the reference internal resistance based on the data related to the electrochemical device includes:
Acquiring an internal resistance and an SOC of the electrochemical device during the interruption;
obtaining a first curve based on the SOC and the internal resistance during each break, the first curve representing a variation of the internal resistance with the SOC;
Differentiating the first curve to obtain a first differential curve;
The lithium-ion SOC is determined based on the first differential curve, and the reference internal resistance is determined based on the first curve.
2. The electrochemical device management method according to claim 1, wherein the value region in which lithium precipitation occurs in the electrochemical device includes a first value region and a second value region;
The first value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a first lithium-precipitation degree; the second value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a second lithium-precipitation degree before the first lithium-precipitation degree;
The determining an end-of-life EOL state of the electrochemical device in response to the target lithium-out SOC and the target internal resistance being at a region of the electrochemical device where lithium-out occurs or a region of the electrochemical device where aging occurs, comprising:
Reducing a charging current of the electrochemical device by a first current reduction step and/or reducing a charge cutoff voltage of the electrochemical device by a first voltage reduction step in response to the target lithium-ion SOC and the target internal resistance being in the first value region; or alternatively
Reducing a charging current of the electrochemical device by a second current reduction step, the second current reduction step being less than the first current reduction step, and/or reducing a charging cutoff voltage of the electrochemical device by a second voltage reduction step, the second voltage reduction step being less than the first voltage reduction step, in response to the target lithium-out SOC and the target internal resistance being in the second value region; or alternatively
And reducing the charging current of the electrochemical device by a third current reduction step and/or reducing the charging cut-off voltage of the electrochemical device by a third voltage reduction step in response to the target lithium-ion SOC and the target internal resistance being in a value region where aging of the electrochemical device occurs, wherein the third current reduction step is smaller than the first current reduction step and the third voltage reduction step is smaller than the first voltage reduction step.
3. The electrochemical device management method according to claim 2, wherein the first value region includes a region in which the reference internal resistance and the lithium SOC satisfy a first value condition;
wherein, the first value condition includes: the reference internal resistance is less than or equal to the first internal resistance threshold and the lithium-eluting SOC is less than or equal to the smaller of the lithium-eluting SOC threshold and the function value of the first function;
The first function includes a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative first slope that characterizes a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a first lithium-eluting level.
4. The electrochemical device management method according to claim 3, wherein the second value region includes a region in which the reference internal resistance and the lithium SOC satisfy a second value condition;
Wherein the second value condition includes: the reference internal resistance is greater than a second internal resistance threshold and less than or equal to the first internal resistance threshold, and the lithium-precipitation SOC is greater than a function value of a first function, less than a smaller one of the lithium-precipitation SOC threshold and a function value of a second function; or the reference internal resistance is larger than the first internal resistance threshold and smaller than or equal to a third internal resistance threshold, and the lithium-precipitation SOC is smaller than the function value of the second function;
The second function includes a linear function having a reference internal resistance as an independent variable, a lithium-eluting SOC as a dependent variable, and a negative second slope characterizing a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a second lithium-eluting level, the first internal resistance threshold being greater than the second internal resistance threshold and less than the third internal resistance threshold.
5. The electrochemical device management method according to claim 4, wherein the region of the electrochemical device where aging occurs includes a region where the reference internal resistance and the lithium SOC satisfy a third value condition;
the third value condition comprises that the reference internal resistance is larger than the third internal resistance threshold value and the lithium-precipitation SOC is smaller than the lithium-precipitation SOC threshold value.
6. The electrochemical device management method of claim 1, wherein the determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance comprises:
taking the lithium-precipitation SOC as the target lithium-precipitation SOC; and
And taking the reference internal resistance as the target internal resistance.
7. The electrochemical device management method according to claim 1, wherein the method further comprises: acquiring at least one historical lithium-ion SOC of the electrochemical device and at least one historical reference internal resistance of the electrochemical device;
The determining a target lithium-out SOC and a target internal resistance based on the lithium-out SOC and the reference internal resistance includes:
Taking a weighted average of the lithium-out SOC and the at least one historical lithium-out SOC as the target lithium-out SOC; and
And taking a weighted average of the reference internal resistance and the at least one historical reference internal resistance as the target internal resistance.
8. The electrochemical device management method according to claim 1, wherein the determining the lithium-ion SOC based on the first differential curve includes at least one of mode A1 and mode A2, wherein,
The mode A1 includes:
determining whether the first differential curve has a maximum value and a minimum value;
If the maximum value and the minimum value exist, determining the SOC corresponding to the maximum value as the lithium-precipitation SOC;
The mode A2 includes:
differentiating the first differential curve to obtain a second differential curve;
And determining the SOC corresponding to the point where the ordinate of the second differential curve appears smaller than zero for the first time as the lithium precipitation SOC.
9. A battery system comprising a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor, when executing the machine-executable instructions, implementing the method of any one of claims 1-8.
10. An electronic device, wherein the electronic device comprises the battery system of claim 9.
11. An electronic device, wherein the electronic device comprises: a data analysis device, a target data determination device and a protection device;
The data analysis device is used for carrying out intermittent charging operation on the electrochemical device, acquiring data related to the electrochemical device in the intermittent charging operation, and determining a lithium-precipitation SOC of the electrochemical device and a reference internal resistance based on the data related to the electrochemical device, wherein the reference internal resistance is used for indicating the internal resistance when the electrochemical device is charged to a first SOC, the lithium-precipitation SOC is the SOC related to the lithium-precipitation state of the electrochemical device, and the smaller the lithium-precipitation SOC is, the more serious the lithium-precipitation state is;
the target data determining device is used for determining a target lithium precipitation SOC and a target internal resistance based on the lithium precipitation SOC and the reference internal resistance;
The protection device is used for determining an EOL state of the electrochemical device at the end of life of the electrochemical device in response to the target lithium precipitation SOC and the target internal resistance being in a lithium precipitation value area of the electrochemical device or an aging value area of the electrochemical device;
Wherein the data related to the electrochemical device includes an SOC of the electrochemical device and an internal resistance of the electrochemical device, the intermittent charging operation includes a plurality of charging periods and a plurality of intermittent periods, and the data analysis device is specifically configured to:
Acquiring an internal resistance and an SOC of the electrochemical device during the interruption;
obtaining a first curve based on the SOC and the internal resistance during each break, the first curve representing a variation of the internal resistance with the SOC;
Differentiating the first curve to obtain a first differential curve;
The lithium-ion SOC is determined based on the first differential curve, and the reference internal resistance is determined based on the first curve.
12. The electronic device according to claim 11, wherein the lithium-generating region of the electrochemical apparatus includes a first region and a second region;
The first value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a first lithium-precipitation degree; the second value area is used for indicating a value range of the lithium-precipitation SOC and the reference internal resistance when the electrochemical device is at a second lithium-precipitation degree before the first lithium-precipitation degree;
The protection device is specifically used for:
Reducing a charging current of the electrochemical device by a first current reduction step and/or reducing a charge cutoff voltage of the electrochemical device by a first voltage reduction step in response to the target lithium-ion SOC and the target internal resistance being in the first value region; or alternatively
Reducing a charging current of the electrochemical device by a second current reduction step, the second current reduction step being less than the first current reduction step, and/or reducing a charging cutoff voltage of the electrochemical device by a second voltage reduction step, the second voltage reduction step being less than the first voltage reduction step, in response to the target lithium-out SOC and the target internal resistance being in the second value region; or alternatively
And reducing the charging current of the electrochemical device by a third current reduction step and/or reducing the charging cut-off voltage of the electrochemical device by a third voltage reduction step in response to the target lithium-ion SOC and the target internal resistance being in a value region where aging of the electrochemical device occurs, wherein the third current reduction step is smaller than the first current reduction step and the third voltage reduction step is smaller than the first voltage reduction step.
13. The electronic device of claim 12, wherein the first valued area comprises an area where a reference internal resistance and lithium SOC meet a first valued condition;
wherein, the first value condition includes: the reference internal resistance is less than or equal to the first internal resistance threshold and the lithium-eluting SOC is less than or equal to the smaller of the lithium-eluting SOC threshold and the function value of the first function;
The first function includes a linear function having a reference internal resistance as an independent variable and a lithium-eluting SOC as a dependent variable, and having a negative first slope that characterizes a maximum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a first lithium-eluting level.
14. The electronic device of claim 13, wherein the second valued area comprises an area where a reference internal resistance and lithium SOC meet a second valued condition;
Wherein the second value condition includes: the reference internal resistance is greater than a second internal resistance threshold and less than or equal to the first internal resistance threshold, and the lithium-precipitation SOC is greater than a function value of a first function, less than a smaller one of the lithium-precipitation SOC threshold and a function value of a second function; or the reference internal resistance is larger than the first internal resistance threshold and smaller than or equal to a third internal resistance threshold, and the lithium-precipitation SOC is smaller than the function value of the second function;
The second function includes a linear function having a reference internal resistance as an independent variable, a lithium-eluting SOC as a dependent variable, and a negative second slope characterizing a minimum rate of decrease of the lithium-eluting SOC with the reference internal resistance when the electrochemical device is at a second lithium-eluting level, the first internal resistance threshold being greater than the second internal resistance threshold and less than the third internal resistance threshold.
15. The electronic apparatus according to claim 14, wherein the region of the electrochemical device where aging occurs includes a region where the reference internal resistance and the lithium SOC satisfy a third value condition;
the third value condition comprises that the reference internal resistance is larger than the third internal resistance threshold value and the lithium-precipitation SOC is smaller than the lithium-precipitation SOC threshold value.
16. The electronic device according to claim 11, wherein the target data determining means is specifically configured to:
taking the lithium-precipitation SOC as the target lithium-precipitation SOC; and
And taking the reference internal resistance as the target internal resistance.
17. The electronic device of claim 11, wherein the electronic device further comprises a historical lithium analysis data acquisition means for acquiring at least one historical lithium analysis SOC of the electrochemical apparatus and at least one historical reference internal resistance of the electrochemical apparatus;
The target data determining device is specifically configured to:
Taking a weighted average of the lithium-out SOC and the at least one historical lithium-out SOC as the target lithium-out SOC; and
And taking a weighted average of the reference internal resistance and the at least one historical reference internal resistance as the target internal resistance.
18. The electronic device of claim 11, wherein the data analysis means is specifically configured to:
At least one of the modes A1 and A2 is performed, wherein,
The mode A1 includes:
determining whether the first differential curve has a maximum value and a minimum value;
If the maximum value and the minimum value exist, determining the SOC corresponding to the maximum value as the lithium-precipitation SOC;
The mode A2 includes:
differentiating the first differential curve to obtain a second differential curve;
And determining the SOC corresponding to the point where the ordinate of the second differential curve appears smaller than zero for the first time as the lithium precipitation SOC.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111389709.1A CN114069077B (en) | 2021-11-22 | Electrochemical device management method, electronic apparatus, and battery system | |
| PCT/CN2022/126986 WO2023088037A1 (en) | 2021-11-22 | 2022-10-24 | Electrochemical apparatus management method, electronic device and battery system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111389709.1A CN114069077B (en) | 2021-11-22 | Electrochemical device management method, electronic apparatus, and battery system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114069077A CN114069077A (en) | 2022-02-18 |
| CN114069077B true CN114069077B (en) | 2024-06-04 |
Family
ID=
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102013002340A1 (en) * | 2013-02-09 | 2014-08-14 | Volkswagen Aktiengesellschaft | Method for testing aging state of accumulator in lithium-ion battery system in electrical or hybrid vehicle, involves checking aging state of energy store using determined clamp resistors internal resistance sizes |
| CN104678316A (en) * | 2015-02-28 | 2015-06-03 | 北京交通大学 | Method and device for estimating charge state of lithium ion battery |
| CN111638461A (en) * | 2020-06-27 | 2020-09-08 | 天能帅福得能源股份有限公司 | Lithium ion battery charging and lithium separating real-time detection method and system |
| CN112710957A (en) * | 2020-12-26 | 2021-04-27 | 清华大学 | Method and device for detecting lithium precipitation during battery charging and computer equipment |
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102013002340A1 (en) * | 2013-02-09 | 2014-08-14 | Volkswagen Aktiengesellschaft | Method for testing aging state of accumulator in lithium-ion battery system in electrical or hybrid vehicle, involves checking aging state of energy store using determined clamp resistors internal resistance sizes |
| CN104678316A (en) * | 2015-02-28 | 2015-06-03 | 北京交通大学 | Method and device for estimating charge state of lithium ion battery |
| CN111638461A (en) * | 2020-06-27 | 2020-09-08 | 天能帅福得能源股份有限公司 | Lithium ion battery charging and lithium separating real-time detection method and system |
| CN112710957A (en) * | 2020-12-26 | 2021-04-27 | 清华大学 | Method and device for detecting lithium precipitation during battery charging and computer equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10135279B2 (en) | Method and apparatus of battery charging | |
| KR102420091B1 (en) | Apparatus and method for diagnosing battery cell | |
| CN102590623B (en) | Secondary battery tester, secondary battery testing method, and manufacturing method of secondary battery | |
| US10564223B2 (en) | Power storage system, control system of secondary battery, and control method of secondary battery | |
| CN114035096B (en) | SOH evaluation method for electrochemical device, electronic equipment and battery system | |
| CN116113837A (en) | Method for estimating state of charge of battery | |
| CN116008827A (en) | Determination method and device for lithium ion battery lithium precipitation potential and electronic equipment | |
| US10481213B2 (en) | Method and device for detecting an overcharging of an accumulator of a battery | |
| CN114252792A (en) | Method and device for detecting internal short circuit of battery pack, electronic equipment and storage medium | |
| CN114069077B (en) | Electrochemical device management method, electronic apparatus, and battery system | |
| WO2018158505A1 (en) | Method, controllling unit and electronic charging arrangement for determining state of charge of a battery during charging of the battery | |
| CN114397582B (en) | Lithium precipitation detection method, electronic device, charging device and storage medium | |
| WO2023088037A1 (en) | Electrochemical apparatus management method, electronic device and battery system | |
| CN112039155A (en) | Charging control method for charging box, charging box and computer readable storage medium | |
| CN115097325B (en) | Battery detection method, device, equipment and storage medium | |
| KR102600139B1 (en) | Apparatus and method for managing battery | |
| KR102618037B1 (en) | Battery diagnosis apparatus, battery diagnosis method, and battery diagnosis system | |
| CN117554845B (en) | Battery health state evaluation method and device, electronic equipment and storage medium | |
| JP7113976B2 (en) | Charge/discharge control device and charge/discharge control method | |
| US20240186809A1 (en) | Full charge capacity estimation method and control device | |
| CN115668580A (en) | Electrochemical device management method, charging device, battery system, and electronic apparatus | |
| JP2017011807A (en) | Discrimination method for charge/discharge quantity and number of charge/discharge times of refresh charge/discharge | |
| CN115097325A (en) | Battery detection method, device, equipment and storage medium | |
| CN114200310A (en) | Electrochemical device lithium analysis detection method and electronic device | |
| KR20230119958A (en) | Apparatus and method for managing battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |