CN114678610B - Method, device and system for determining safety boundary of battery charging strategy - Google Patents
Method, device and system for determining safety boundary of battery charging strategy Download PDFInfo
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Abstract
The application discloses a method, a device and a system for determining a battery charging strategy safety boundary, and relates to the technical field of automobiles; the charging strategy can be dynamically adjusted based on a detection result of whether the lithium precipitation phenomenon exists in the charging process of the battery, voltage information of a static stage of the battery is obtained after the battery is charged by the adjusted charging strategy, whether the lithium precipitation phenomenon exists in the charging process of the battery is detected according to the voltage information of the static stage of the battery, and a safety boundary of the charging strategy of the battery is determined according to the detection result, wherein the safety boundary of the charging strategy comprises at least one of a lithium-precipitation-free upper limit current, a lithium-precipitation-free lower limit temperature and a lithium-precipitation-free upper limit voltage. The scheme of the application realizes the accurate measurement of the safety boundary of the charging strategy of the battery.
Description
Technical Field
The present application relates to the field of automotive technologies, and in particular, to a method, an apparatus, and a system for determining a safety boundary of a battery charging policy.
Background
In recent years, the electric automobile industry in China rapidly develops, and along with the increase of market conservation quantity, the safety problem of the electric automobile is increasingly prominent, and particularly in recent years, the electric automobile has more and more frequent fire events. The essence of the ignition of the electric automobile is thermal runaway of the battery, and accident statistics show that in the charging process, if a charging strategy is not proper, lithium is separated from the battery, and the safety of the battery after lithium separation is greatly reduced, so that the battery is easier to trigger the thermal runaway, and therefore, the short-term standing stage during and after the charging is a high-occurrence stage of the thermal runaway of the battery.
Currently, lithium ion batteries are widely used as power batteries for electric vehicles. In order to greatly shorten the charging time and further improve the charging convenience, the main measure adopted at present is to improve the current of the battery in the charging process. However, since the negative electrode material of the commercial lithium ion battery mostly adopts a carbon material based on graphite, the potential of the carbon material to lithium is low, so that metal lithium is easy to be precipitated at the negative electrode in the charging process of the lithium ion battery. After lithium is separated from the battery, the thermal stability of the anode material is reduced due to the existence of active lithium, the self-heating initial temperature of the battery is reduced, and thermal runaway is more likely to occur. How to improve the charging rate of a battery and simultaneously ensure the safety of the charging process is a primary consideration when charging the battery.
The existing battery charging strategy formulation method mainly comprises the steps of preparing a special three-electrode battery system according to the characteristics of different batteries when the charging strategy is formulated, monitoring the potential of a negative electrode in real time to keep the potential above the lithium precipitation potential all the time, and further improving the charging multiplying power if the potential of the negative electrode does not exceed the lithium precipitation potential of the battery. However, the strategy needs to prepare a special battery device in advance, and the preparation process of the special battery device has certain technical requirements, and in addition, although the adoption of the negative electrode potential to observe whether lithium is separated or not is feasible in theory, a certain hysteresis phenomenon exists between the actual lithium separation condition in the battery and the negative electrode potential, and a certain error exists in the measurement result.
Disclosure of Invention
The application aims to provide a method, a device and a system for determining a battery charging strategy safety boundary, so that the problem of low measurement accuracy of the battery charging strategy safety boundary in the prior art is solved.
In order to achieve the above object, the present application provides a method for determining a safety boundary of a battery charging policy, comprising:
the method comprises the steps of obtaining a dynamically adjusted charging strategy, wherein the charging strategy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process;
respectively charging the battery by using the adjusted charging strategy, and then obtaining voltage information of the battery in a standing stage;
detecting whether a lithium precipitation phenomenon exists in the battery in the charging process according to voltage information of the battery in a standing stage;
determining a safety boundary of a charging strategy of the battery according to the detection result, wherein the safety boundary of the charging strategy comprises at least one of the following:
upper limit current of lithium is not separated;
The lower limit temperature of lithium is not separated;
The upper limit voltage of lithium is not analyzed.
Optionally, the charging strategy comprises at least one of a charging cutoff voltage and a charging temperature:
Dynamically adjusting the charging strategy based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, wherein the method comprises at least one of the following steps:
under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by using the first charging strategy is detected, the charging temperature in the first charging strategy is reduced, and the adjusted charging strategy is obtained;
And under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by using the first charging strategy, the charging cut-off voltage in the first charging strategy is regulated, and the regulated charging strategy is obtained.
Optionally, determining a safety boundary of a charging policy of the battery according to the detection result includes:
And under the condition that the detection result corresponding to the adjusted charging strategy is that the lithium precipitation phenomenon exists, determining at least one of a charging cut-off voltage and a charging temperature contained in the charging strategy utilized in the previous charging process adjacent to the charging process with the lithium precipitation phenomenon as a safety boundary of the charging strategy.
Optionally, the charging strategy includes a charging current;
Dynamically adjusting the charging strategy based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, wherein the method comprises at least one of the following steps:
When the situation that lithium precipitation phenomenon does not exist in the process of charging the battery by using a second charging strategy is detected, and a second charging current corresponding to the second charging strategy is larger than a first charging current is detected, the second charging current is regulated by a first preset regulating value to obtain a regulated third charging strategy;
when the phenomenon of lithium precipitation exists in the process of charging the battery by using the second charging strategy is detected, and the second charging current corresponding to the second charging strategy is larger than the first charging current, reducing the second charging current by a second preset adjustment value to obtain an adjusted fourth charging strategy, wherein the second preset adjustment value is smaller than the first preset adjustment value;
And when the phenomenon of lithium precipitation exists in the process of charging the battery by using the second charging strategy is detected, and the second charging current corresponding to the second charging strategy is smaller than the first charging current, reducing the second charging current by a second preset adjustment value to obtain an adjusted fifth charging strategy.
Optionally, the method further comprises:
and stopping adjusting the charging strategy based on a detection result of whether the lithium precipitation phenomenon exists in the charging process of the battery under the condition that the adjusted fifth charging current corresponding to the fifth charging strategy is a preset current.
Optionally, determining a safety boundary of a charging strategy of the battery according to the detection result, wherein the safety boundary comprises at least one of the following steps:
Under the condition that no lithium precipitation phenomenon exists in the process of charging the battery by utilizing the fourth charging strategy, determining the charging current corresponding to the fourth charging strategy as the upper limit current without lithium precipitation;
Under the condition that the phenomenon of lithium precipitation exists in the process of charging the battery by utilizing the fourth charging strategy, determining that the difference value between the charging current corresponding to the fourth charging strategy and the second preset adjustment value is the upper limit current without lithium precipitation;
Determining that the difference value between the charging current corresponding to the fifth charging strategy and the second preset adjustment value is the upper limit current without lithium precipitation when the phenomenon of lithium precipitation exists in the process of charging the battery by using the fifth charging strategy and the charging current corresponding to the fifth charging strategy is a preset current is detected;
And under the condition that no lithium precipitation phenomenon exists in the process of charging the battery by utilizing the fifth charging strategy, determining the charging current corresponding to the fifth charging strategy as the upper limit current without lithium precipitation.
Optionally, detecting whether the lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery in the standing stage includes:
And under the condition that the voltage information of the battery in the standing stage is a voltage curve and the voltage curve has a minimum value, determining that the lithium precipitation phenomenon exists in the battery in the charging process.
The embodiment of the application also provides a device for determining the safety boundary of the battery charging strategy, which comprises the following steps:
The charging system comprises a first acquisition module, a second acquisition module and a third acquisition module, wherein the first acquisition module is used for acquiring a dynamically adjusted charging strategy, and the charging strategy can be dynamically adjusted based on the detection result of whether a lithium precipitation phenomenon exists in the battery in the charging process;
The second acquisition module is used for acquiring voltage information of the battery in a standing stage after the battery is charged by utilizing the adjusted charging strategy respectively;
The detection module is used for detecting whether the lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery in the standing stage;
The determining module is used for determining the safety boundary of the charging strategy of the battery according to the detection result, wherein the safety boundary of the charging strategy comprises at least one of the following:
upper limit current of lithium is not separated;
The lower limit temperature of lithium is not separated;
The upper limit voltage of lithium is not analyzed.
The embodiment of the application also provides a system for determining the safety boundary of the battery charging strategy, which comprises a processor, a memory and a program stored in the memory and capable of running on the processor, wherein the program realizes the steps of the method for determining the safety boundary of the battery charging strategy when being executed by the processor.
The embodiment of the application also provides a readable storage medium, wherein a program is stored on the readable storage medium, and the program realizes the steps of the method for determining the safety boundary of the battery charging strategy when being executed by a processor.
The technical scheme of the application has at least the following beneficial effects:
The method for determining the safety boundary of the battery charging strategy comprises the steps of firstly, obtaining a dynamically adjusted charging strategy, wherein the charging strategy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, secondly, respectively utilizing the adjusted charging strategy to charge the battery, obtaining voltage information of a battery standing stage, detecting whether the lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery standing stage, and finally, determining the safety boundary of the battery charging strategy according to a detection result, wherein the safety boundary of the charging strategy comprises at least one of upper limit current without lithium precipitation, lower limit temperature without lithium precipitation and upper limit voltage without lithium precipitation. The method of the embodiment of the application realizes the accurate measurement of the safety boundary of the charging strategy of the battery on the basis of not preparing a special battery device, simplifies the detection process and reduces the detection cost.
Drawings
FIG. 1 is a flowchart of a method for determining a battery charging policy security boundary according to an embodiment of the present application;
FIG. 2 is a second flowchart of a method for determining a battery charging policy security boundary according to an embodiment of the application;
FIG. 3 is a third flow chart illustrating a method for determining a battery charging policy security boundary according to an embodiment of the application;
FIG. 4 is a flowchart illustrating a method for determining a battery charging policy security boundary according to an embodiment of the present application;
FIG. 5 is a schematic diagram of a voltage curve of a battery in a stationary phase according to an embodiment of the present application;
FIG. 6 is a second schematic diagram of a voltage curve of a battery in a stationary phase according to an embodiment of the application;
fig. 7 is a schematic structural diagram of a device for determining a battery charging policy safety boundary according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the application may be practiced otherwise than as specifically illustrated or described herein. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.
The method, the device and the system for determining the battery charging policy safety boundary provided by the embodiment of the application are described in detail below through specific embodiments and application scenes thereof with reference to the accompanying drawings.
As shown in fig. 1, one of the structural diagrams of a method for determining a safety boundary of a battery charging policy according to an embodiment of the present application is shown, and the method includes:
step 101, acquiring a dynamically adjusted charging strategy, wherein the charging strategy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery charging process;
Here, "lithium" is a loss condition of a lithium ion battery. Specifically, li+ is deintercalated from the positive electrode and is inserted into the negative electrode during charging of the lithium ion battery, but when abnormal conditions such as insufficient lithium insertion space of the negative electrode, too large resistance of the Li+ to be inserted into the negative electrode, too fast deintercalation of Li+ from the positive electrode but incapacity of being inserted into the negative electrode and the like occur, li+ which cannot be inserted into the negative electrode can only obtain electrons on the surface of the negative electrode, so that a silvery white metal lithium simple substance is formed, namely lithium precipitation. The lithium precipitation can not only reduce the battery performance and greatly shorten the cycle life, but also limit the quick charge capacity of the battery, and possibly cause disastrous consequences such as combustion, explosion and the like.
In addition, in this step, when the charging policy is adjusted, one charging parameter in the charging policy is adjusted each time, thereby realizing measurement of the safety boundary of the adjusted charging parameter.
102, Respectively charging the battery by using the adjusted charging strategies, and then obtaining voltage information of the battery in a standing stage;
In this step, the voltage information of the battery in the rest phase may be a voltage change condition of the battery in the rest phase after the completion of the charging process.
Step 103, detecting whether a lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery in the standing stage;
Here, it should be noted that, if the metal lithium is precipitated from the negative electrode of the battery during the charging process, the subsequent rest process of the whole charger can be divided into four phases, namely, a normal charging phase, a negative electrode overpotential is greater than 0, only a reaction of lithium intercalation graphite occurs at this time, a lithium precipitation phase, a lithium precipitation reaction occurs from a negative electrode overpotential of less than 0V, a small part of solid electrolyte interface (Solid Electrolyte Interphase, SEI) film or dead lithium is generated, most of the solid electrolyte interface exists in the form of reversible lithium, the reversible lithium dissolution and re-intercalation phase, the negative electrode overpotential rises to more than 0V, the reversible lithium is dissolved in the electrolyte, and re-intercalation graphite begins, the phase may occur at the initial stage of constant voltage charging or rest, and the complete rest phase, all the reversible lithium is completely dissolved, and the negative electrode does not react any more. In the process of re-intercalation of precipitated lithium into graphite, a platform (a curve in a rectangular frame in the figure) shown in fig. 5 is caused to appear in a battery standing voltage curve, and in order to further amplify and capture the characteristic, the battery standing voltage curve is subjected to differential treatment to obtain a dV/dt-t curve (shown in fig. 6), when the curve has a minimum value, the fact that metal lithium is precipitated in the current charge is proved, the linear relationship exists between the duration of the voltage platform (namely the minimum value occurrence time t_m of the dV/dt-t curve) and the amount of reversible lithium, meanwhile, the reversible lithium and the dead lithium meet a fixed proportion relationship (determined according to a battery core), and the method can be used for quantitative detection of the reversible lithium and the dead lithium. Therefore, according to the voltage information of the battery in the standing stage, whether the lithium precipitation phenomenon exists in the charging process of the battery can be detected.
Step 104, determining a safety boundary of a charging strategy of the battery according to the detection result, wherein the safety boundary of the charging strategy comprises at least one of the following:
upper limit current of lithium is not separated;
The lower limit temperature of lithium is not separated;
The upper limit voltage of lithium is not analyzed.
In the step, the upper limit current without lithium precipitation refers to the maximum safe current value without lithium precipitation signal at a certain temperature in the charging process, the lower limit temperature without lithium precipitation refers to the minimum temperature value without lithium precipitation signal at a certain charging current in the charging process, and the upper limit voltage without lithium precipitation refers to the maximum voltage value without lithium precipitation signal at a certain temperature and charging current in the charging process.
The method for determining the safety boundary of the battery charging strategy comprises the steps of firstly, obtaining a dynamically adjusted charging strategy, wherein the charging strategy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, secondly, respectively utilizing the adjusted charging strategy to charge the battery, obtaining voltage information of a battery standing stage, detecting whether the lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery standing stage, and finally, determining the safety boundary of the battery charging strategy according to a detection result, wherein the safety boundary of the charging strategy comprises at least one of upper limit current without lithium precipitation, lower limit temperature without lithium precipitation and upper limit voltage without lithium precipitation. The method of the embodiment of the application realizes the accurate measurement of the safety boundary of the charging strategy of the battery on the basis of not preparing a special battery device, simplifies the detection process and reduces the detection cost.
As an alternative implementation, the charging strategy includes at least one of a charging cutoff voltage and a charging temperature:
Dynamically adjusting the charging strategy based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, wherein the method comprises at least one of the following steps:
under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by using the first charging strategy is detected, the charging temperature in the first charging strategy is reduced, and the adjusted charging strategy is obtained;
And under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by using the first charging strategy, the charging cut-off voltage in the first charging strategy is regulated, and the regulated charging strategy is obtained.
The method comprises the steps of determining a non-lithium-precipitation upper limit voltage, adjusting a charging cut-off voltage in a charging strategy according to whether a lithium-precipitation phenomenon exists in a charging process or not, and adjusting the charging temperature in the charging strategy according to whether the lithium-precipitation phenomenon exists in the charging process or not when determining the non-lithium-precipitation lower limit temperature so as to realize adjustment of a single parameter, thereby determining a safety boundary of the adjusted parameter.
As an optional implementation manner, step 104, determining, according to the detection result, a safety boundary of the charging policy of the battery includes:
And under the condition that the detection result corresponding to the adjusted charging strategy is that the lithium precipitation phenomenon exists, determining at least one of a charging cut-off voltage and a charging temperature contained in the charging strategy utilized in the previous charging process adjacent to the charging process with the lithium precipitation phenomenon as a safety boundary of the charging strategy.
That is, when determining the non-lithium-precipitation lower limit temperature, if a lithium-precipitation phenomenon is detected in the charging process at the current temperature, determining the non-lithium-precipitation lower limit temperature of the battery as the battery temperature of the charging strategy of the previous charging process, and when determining the non-lithium-precipitation upper limit voltage, if a lithium-precipitation phenomenon is detected in the charging process of the current charging cut-off voltage, determining the non-lithium-precipitation upper limit voltage of the battery as the charging cut-off voltage in the charging strategy of the previous charging process.
The process of determining the lithium-ion-free lower limit temperature will be described below with reference to fig. 2:
When the current charging strategy meets the condition of no lithium precipitation at any temperature point and charging multiplying power, lithium precipitation safety current evaluation can be carried out, and the part simulates a scene that the actual charging multiplying power of the battery is larger than the maximum allowable charging current at the temperature due to the acquisition error (5 ℃) of a temperature sensor and the temperature difference between the inside and the outside of a battery core. The evaluation is realized by adjusting the charging temperature under a certain charging strategy in the charging process, and the specific flow is as follows (refer to fig. 2):
The battery temperature is reduced by 5 ℃ on the basis of the original temperature, namely, the current charging strategy is tested under the condition that the original charging temperature is reduced by 5 ℃ (the influence caused by the temperature acquisition error of a battery management system and the lowest temperature and the highest temperature distribution in a battery pack is referred);
judging whether a lithium precipitation phenomenon exists or not, namely, judging whether a lithium precipitation signal can be detected at the current charging current after confirming the adjustment temperature according to a lithium precipitation detection method;
If judging that the lithium separation phenomenon exists, namely, detecting a lithium separation signal, considering the original charging temperature as a lower limit temperature of no lithium separation (simultaneously, satisfying that the lithium separation signal is detected when the lower limit temperature of no lithium separation is reduced by 5 ℃ for charging);
if the lithium precipitation phenomenon is judged to be absent, the temperature is reduced by 10 ℃ on the basis of the original temperature, and the test is carried out;
and determining the lower limit temperature of the non-lithium precipitation under each charging current according to the lithium precipitation detection result (the lower limit temperature of the non-lithium precipitation under different charging currents can be different).
That is, the process of determining the non-lithium-precipitation lower limit temperature is to adjust the charging temperature by 5 ℃ based on the original temperature on the basis that the lithium-precipitation phenomenon does not exist in the charging process at the original temperature, to detect whether the lithium-precipitation phenomenon exists in the charging process at the adjusted temperature, to determine that the non-lithium-precipitation lower limit temperature is the original temperature if the lithium-precipitation phenomenon exists, to adjust the charging temperature by 10 ℃ based on the original temperature if the lithium-precipitation phenomenon does not exist, to detect whether the lithium-precipitation phenomenon exists in the charging process at the adjusted temperature, to determine that the non-lithium-precipitation lower limit temperature is the original temperature minus 5 ℃, to further adjust the charging temperature by 15 ℃ based on the original temperature if the lithium-precipitation phenomenon does not exist, and to perform such a cycle until the lithium-precipitation phenomenon is detected.
The process of determining the lithium-free upper limit voltage will be described below with reference to fig. 3:
Under the condition that the current charging strategy meets the condition that lithium is not separated out at any temperature point and charging multiplying power, lithium separation safety voltage evaluation can be carried out, and the part simulates a scene that the upper limit of the cut-off voltage is exceeded in the battery charging process caused by the acquisition error of the voltage sensor. By adjusting a specific temperature in the charging process, the charging cut-off voltage is evaluated under a specific charging strategy, and the specific flow is as follows (refer to fig. 3):
The charge cut-off voltage is increased by 50mV based on the original charge cut-off voltage, namely the charge cut-off voltage of the current charge strategy is increased and decreased by 50mV (the upper voltage limit of each part which is not charged is increased by 50 mV) for testing;
Judging whether a lithium separation phenomenon exists or not, namely determining whether a lithium separation signal can be detected after adjusting the upper limit of the charging cut-off voltage according to a lithium separation detection method;
If judging that the lithium precipitation phenomenon exists, namely, detecting a lithium precipitation signal, considering the original charging cut-off voltage as the upper limit voltage of no lithium precipitation;
If the lithium separation phenomenon is judged to be absent, 100mV is increased on the basis of the original charging cut-off voltage, and a test is performed until a lithium separation signal is detected (meanwhile, the lithium separation signal is detected when 50mV is added to the upper limit voltage without lithium separation for charging), and the cut-off voltage under the current charging temperature and charging strategy is considered to be the upper limit voltage without lithium separation;
And determining each charging temperature and the upper limit voltage of the lithium which is not precipitated under the charging strategy according to the lithium precipitation detection result (the upper limit voltage of the lithium which is not precipitated under different temperatures and charging strategies can be different).
The method comprises the steps of determining the upper limit voltage of the non-lithium-precipitation, namely, on the basis that the lithium-precipitation phenomenon does not exist in the charging process under the original charging cut-off voltage, increasing the charging cut-off voltage by 100mV on the basis of the original charging cut-off voltage, detecting whether the lithium-precipitation phenomenon exists in the charging process under the adjusted charging cut-off voltage, if the lithium-precipitation phenomenon exists, determining the upper limit voltage of the non-lithium-precipitation to be the original charging cut-off voltage plus 50mV, increasing the charging cut-off voltage by 150mV on the basis of the original charging cut-off voltage, detecting, and circulating until the lithium-precipitation phenomenon is detected.
As an alternative implementation, the charging strategy includes a charging current;
Dynamically adjusting the charging strategy based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, wherein the method comprises at least one of the following steps:
When the situation that lithium precipitation phenomenon does not exist in the process of charging the battery by using a second charging strategy is detected, and a second charging current corresponding to the second charging strategy is larger than a first charging current is detected, the second charging current is regulated by a first preset regulating value to obtain a regulated third charging strategy;
when the phenomenon of lithium precipitation exists in the process of charging the battery by using the second charging strategy is detected, and the second charging current corresponding to the second charging strategy is larger than the first charging current, reducing the second charging current by a second preset adjustment value to obtain an adjusted fourth charging strategy, wherein the second preset adjustment value is smaller than the first preset adjustment value;
And when the phenomenon of lithium precipitation exists in the process of charging the battery by using the second charging strategy is detected, and the second charging current corresponding to the second charging strategy is smaller than the first charging current, reducing the second charging current by a second preset adjustment value to obtain an adjusted fifth charging strategy.
That is, depending on whether or not a lithium precipitation phenomenon exists during the charging process, the charging current may be adjusted to be larger or smaller to determine the lithium non-precipitation upper limit current.
Further, as an alternative implementation, the method further includes:
and stopping adjusting the charging strategy based on a detection result of whether the lithium precipitation phenomenon exists in the charging process of the battery under the condition that the adjusted fifth charging current corresponding to the fifth charging strategy is a preset current.
That is, since it is known that the lithium precipitation phenomenon does not exist in the charging process using the charging strategy including the original charging current, in order to avoid the repeated test of the charging strategy in which the current in the charging strategy is the original charging current or less than the original charging current, the alternative implementation method does not adjust the charging strategy when the charging current corresponding to the adjusted charging strategy reaches the preset current.
As an optional implementation manner, step 104, determining, according to the detection result, a safety boundary of the charging policy of the battery includes at least one of the following:
Under the condition that no lithium precipitation phenomenon exists in the process of charging the battery by utilizing the fourth charging strategy, determining the charging current corresponding to the fourth charging strategy as the upper limit current without lithium precipitation;
Under the condition that the phenomenon of lithium precipitation exists in the process of charging the battery by utilizing the fourth charging strategy, determining that the difference value between the charging current corresponding to the fourth charging strategy and the second preset adjustment value is the upper limit current without lithium precipitation;
Determining that the difference value between the charging current corresponding to the fifth charging strategy and the second preset adjustment value is the upper limit current without lithium precipitation when the phenomenon of lithium precipitation exists in the process of charging the battery by using the fifth charging strategy and the charging current corresponding to the fifth charging strategy is a preset current is detected;
And under the condition that no lithium precipitation phenomenon exists in the process of charging the battery by utilizing the fifth charging strategy, determining the charging current corresponding to the fifth charging strategy as the upper limit current without lithium precipitation.
That is, in the two adjacent charging processes, the lithium precipitation phenomenon exists in one charging process, and in the case that the lithium precipitation phenomenon does not exist in the other charging process, the upper limit current without lithium precipitation is determined as the charging current corresponding to the charging strategy utilized in the charging process without the lithium precipitation phenomenon.
The process of determining the lithium-free upper limit current will be described below with reference to fig. 4:
When the current charging strategy meets the condition that lithium is not separated out at any temperature point and charging multiplying power, lithium separation safety current evaluation can be carried out, and the current analysis method simulates a scene that the current caused by errors or other conditions in current collection of the BMS and the charging pile exceeds the current allowed maximum charging current. The charging current is evaluated by adjusting a specific temperature in the charging strategy, and the specific flow is as follows (refer to fig. 4):
The charging current is adjusted to be 1.2 times of the original charging current, namely, the charging current at different temperatures in the current charging strategy is adjusted to be 1.2 times of the original charging current (referring to the current fault threshold value in the BMS parameter table), and the adjusted current is adopted to charge the battery at different temperatures;
Judging whether a lithium separation phenomenon exists or not, namely, determining whether a lithium separation signal can be detected at the current charging current at each temperature according to a lithium separation detection method;
If judging that the lithium precipitation phenomenon exists, namely, if a lithium precipitation signal is detected, adjusting the charging current to be 1.15 times, restarting detection until the lithium precipitation signal is not detected (meanwhile, the lithium precipitation signal is detected after the initial current is increased by 0.05 times when the lithium precipitation-free upper limit current is met), and considering the current charging current as the lithium precipitation-free upper limit current at the temperature;
If it is judged that the lithium precipitation phenomenon does not exist, namely, if a lithium precipitation signal is not detected, the charging current is adjusted to be 1.3 times, detection is restarted until the lithium precipitation signal is detected (meanwhile, the lithium precipitation signal is detected after the initial current is increased by 0.05 times when the lithium precipitation-free upper limit current is met), and the current charging current is regarded as the lithium precipitation-free upper limit current at the temperature.
And determining the upper limit current of the lithium which is not precipitated at each temperature point according to the lithium precipitation detection result (the multiple relation between the upper limit current of the lithium which is not precipitated at different temperature points and the original charging current can be different).
As an optional implementation manner, step 103, detecting whether the lithium precipitation phenomenon exists in the battery during the charging process according to the voltage information of the battery in the standing stage includes:
And under the condition that the voltage information of the battery in the standing stage is a voltage curve and the voltage curve has a minimum value, determining that the lithium precipitation phenomenon exists in the battery in the charging process.
Specifically, as shown in fig. 5 and 6, since the lithium precipitated will cause a platform to appear in the standing voltage of the battery during the process of re-intercalation of graphite, in order to further amplify and capture this feature, the standing voltage curve (curve in fig. 5) of the battery is subjected to differential processing to obtain a dV/dt-t curve (curve in fig. 6), and when the curve has a minimum value, it is proved that the lithium metal is precipitated in the present charge.
The method for determining the safety boundary of the battery charging strategy comprises the steps of firstly, obtaining a dynamically adjusted charging strategy, wherein the charging strategy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, secondly, respectively utilizing the adjusted charging strategy to charge the battery, obtaining voltage information of a battery standing stage, detecting whether the lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery standing stage, and finally, determining the safety boundary of the battery charging strategy according to a detection result, wherein the safety boundary of the charging strategy comprises at least one of upper limit current without lithium precipitation, lower limit temperature without lithium precipitation and upper limit voltage without lithium precipitation. Therefore, on the basis of not preparing a special battery device, the method realizes accurate measurement of the safety boundary of the charging strategy of the battery, simplifies the detection process and reduces the detection cost, and the method realizes detection of the rhinorrhea inside the resting voltage of the battery and the final lithium precipitation state detection of the battery.
As shown in fig. 7, an embodiment of the present application further provides a device for determining a safety boundary of a battery charging policy, including:
the first obtaining module 701 is configured to obtain a dynamically adjusted charging policy, where the charging policy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery during a charging process;
the second obtaining module 702 is configured to obtain voltage information of the battery in a standing stage after the battery is charged by using the adjusted charging policies respectively;
the detection module 703 is configured to detect whether a lithium precipitation phenomenon exists in the battery during the charging process according to the voltage information of the battery in the standing stage;
a determining module 704, configured to determine a safety boundary of a charging policy of the battery according to the detection result, where the safety boundary of the charging policy includes at least one of:
upper limit current of lithium is not separated;
The lower limit temperature of lithium is not separated;
The upper limit voltage of lithium is not analyzed.
According to the determining device for the safety boundary of the battery charging strategy, firstly, a first obtaining module 701 obtains a dynamically adjusted charging strategy, the charging strategy can be dynamically adjusted based on a detection result of whether a lithium precipitation phenomenon exists in a battery in a charging process, secondly, a second obtaining module 702 obtains voltage information of a battery standing stage after the battery is charged by the aid of the adjusted charging strategy respectively, thirdly, a detecting module 703 detects whether the lithium precipitation phenomenon exists in the battery in the charging process according to the voltage information of the battery standing stage, and finally, a determining module 704 determines the safety boundary of the battery charging strategy according to the detection result, wherein the safety boundary of the charging strategy comprises at least one of a lithium-precipitation-free upper limit current, a lithium-precipitation-free lower limit temperature and a lithium-precipitation-free upper limit voltage. Therefore, on the basis of not preparing a special battery device, the method realizes accurate measurement of the safety boundary of the charging strategy of the battery, simplifies the detection process and reduces the detection cost, and the method realizes detection of the rhinorrhea inside the resting voltage of the battery and the final lithium precipitation state detection of the battery.
Optionally, the charging strategy comprises at least one of a charging cutoff voltage and a charging temperature:
The first obtaining module 701 is configured to dynamically adjust the charging policy based on a detection result of whether a lithium precipitation phenomenon exists in a charging process of the battery, and is specifically configured to:
under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by using the first charging strategy is detected, the charging temperature in the first charging strategy is reduced, and the adjusted charging strategy is obtained;
Or under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by using the first charging strategy, the charging cut-off voltage in the first charging strategy is regulated to obtain the regulated charging strategy.
Optionally, the determining module 704 is specifically configured to determine, when the detection result corresponding to the adjusted charging policy is that the lithium precipitation phenomenon exists, at least one of a charging cutoff voltage and a charging temperature included in a charging policy utilized by a previous charging process adjacent to the charging process in which the lithium precipitation phenomenon exists as a safety boundary of the charging policy.
Optionally, the charging strategy includes a charging current;
The first obtaining module 701 is configured to dynamically adjust the charging policy based on a detection result of whether a lithium precipitation phenomenon exists in a charging process of the battery, and is specifically configured to:
When the situation that lithium precipitation phenomenon does not exist in the process of charging the battery by using a second charging strategy is detected, and a second charging current corresponding to the second charging strategy is larger than a first charging current is detected, the second charging current is regulated by a first preset regulating value to obtain a regulated third charging strategy;
Or when the lithium precipitation phenomenon exists in the process of charging the battery by using the second charging strategy is detected, and the second charging current corresponding to the second charging strategy is larger than the first charging current, reducing the second charging current by a second preset adjustment value to obtain an adjusted fourth charging strategy, wherein the second preset adjustment value is smaller than the first preset adjustment value;
or when the lithium precipitation phenomenon exists in the process of charging the battery by using the second charging strategy is detected, and the second charging current corresponding to the second charging strategy is smaller than the first charging current, the second charging current is reduced by a second preset adjustment value, and an adjusted fifth charging strategy is obtained.
Further, the apparatus further comprises:
and the stopping module is used for stopping the adjustment of the charging strategy based on the detection result of whether the lithium precipitation phenomenon exists in the charging process of the battery under the condition that the adjusted fifth charging current corresponding to the fifth charging strategy is the preset current.
Optionally, the determining module 704 is specifically configured to:
Under the condition that no lithium precipitation phenomenon exists in the process of charging the battery by utilizing the fourth charging strategy, determining the charging current corresponding to the fourth charging strategy as the upper limit current without lithium precipitation;
Or under the condition that the phenomenon of lithium precipitation exists in the process of charging the battery by utilizing the fourth charging strategy, determining that the difference value between the charging current corresponding to the fourth charging strategy and the second preset adjustment value is the upper limit current without lithium precipitation;
Or under the condition that the lithium precipitation phenomenon exists in the process of charging the battery by utilizing the fifth charging strategy and the charging current corresponding to the fifth charging strategy is a preset current, determining that the difference value between the charging current corresponding to the fifth charging strategy and the second preset adjustment value is the upper limit current without the lithium precipitation;
or under the condition that the phenomenon of lithium precipitation does not exist in the process of charging the battery by utilizing the fifth charging strategy, determining the charging current corresponding to the fifth charging strategy as the upper limit current without lithium precipitation.
Optionally, the detection module 703 is specifically configured to determine that a lithium precipitation phenomenon exists in the battery during the charging process when the voltage information of the battery in the standing stage is a voltage curve and the voltage curve has a minimum value.
The embodiment of the application also provides a system for determining the safety boundary of the battery charging strategy, which comprises a processor, a memory and a program stored in the memory and capable of running on the processor, wherein the program realizes the processes of the method embodiment for determining the safety boundary of the battery charging strategy when being executed by the processor, can achieve the same technical effects, and is not repeated here for avoiding repetition.
The embodiment of the application also provides a readable storage medium, and a program is stored on the readable storage medium, and when the program is executed by a processor, the program realizes each process of the method embodiment for determining the safety boundary of the battery charging strategy, and can achieve the same technical effect, so that repetition is avoided, and no repeated description is provided here. The readable storage medium is, for example, a Read-Only Memory (ROM), a random access Memory (Random Access Memory RAM), a magnetic disk, an optical disk, or the like.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.
While the foregoing is directed to the preferred embodiments of the present application, it will be appreciated by those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present application, and such modifications and adaptations are intended to be comprehended within the scope of the present application.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107516750A (en) * | 2017-08-03 | 2017-12-26 | 国联汽车动力电池研究院有限责任公司 | A method and device for determining safe charging conditions for lithium-ion batteries |
| CN110061315A (en) * | 2019-03-29 | 2019-07-26 | 欣旺达电动汽车电池有限公司 | A kind of lithium ion battery fast charge method |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101798201B1 (en) * | 2014-10-01 | 2017-11-15 | 주식회사 엘지화학 | Method and Apparatus for estimating discharge power of secondary battery |
| JP2017099165A (en) * | 2015-11-25 | 2017-06-01 | トヨタ自動車株式会社 | Lithium ion secondary battery charge control device |
| DE112019005568T5 (en) * | 2018-11-07 | 2021-08-05 | Qnovo Inc. | Adaptive battery charging |
| CN111198328A (en) * | 2018-11-19 | 2020-05-26 | 微宏动力系统（湖州）有限公司 | Battery lithium separation detection method and battery lithium separation detection system |
| CN109546248B (en) * | 2018-11-30 | 2021-07-30 | 合肥国轩高科动力能源有限公司 | An optimization method of lithium-ion battery charging strategy |
| CN109586373B (en) * | 2018-12-27 | 2024-05-17 | 华为技术有限公司 | Battery charging method and device |
| CN110137584B (en) * | 2019-03-20 | 2020-12-11 | 北京车和家信息技术有限公司 | Charging voltage threshold determination method and charging strategy determination method |
| CN112582696B (en) * | 2019-09-29 | 2022-05-20 | 宁德新能源科技有限公司 | Charging method, electronic device, and storage medium |
| CN111342159B (en) * | 2020-03-06 | 2021-11-16 | Oppo广东移动通信有限公司 | Charging control method and device, electronic equipment and computer readable storage medium |
| CN112038719B (en) * | 2020-07-28 | 2023-08-25 | 天津力神电池股份有限公司 | Method for formulating lithium ion battery quick charge strategy |
| CN112572233B (en) * | 2020-12-30 | 2022-08-19 | 广州橙行智动汽车科技有限公司 | Battery management method and device and vehicle |
| CN112782582B (en) * | 2021-01-29 | 2023-09-15 | 远景动力技术(江苏)有限公司 | Method for detecting lithium ion battery negative electrode lithium precipitation |
-
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- 2021-07-14 CN CN202110794901.2A patent/CN114678610B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107516750A (en) * | 2017-08-03 | 2017-12-26 | 国联汽车动力电池研究院有限责任公司 | A method and device for determining safe charging conditions for lithium-ion batteries |
| CN110061315A (en) * | 2019-03-29 | 2019-07-26 | 欣旺达电动汽车电池有限公司 | A kind of lithium ion battery fast charge method |
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