Lithium precipitation detection method and device of battery, storage medium and processor

Abstract

The application discloses a lithium precipitation detection method and device of a battery, a storage medium and a processor. The method comprises the following steps: obtaining a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery; determining a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; determining a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent the degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; and determining that lithium precipitation occurs in the battery when the capacity change rate is greater than the target reference value. The application solves the technical problem that the determination of lithium precipitation is not timely, and the battery life and safety are affected due to the fact that the lithium precipitation detection method in the related art is not suitable for online detection and has poor detection sensitivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery detection, in particular to a lithium precipitation detection method and device for a battery, a storage medium and a processor. BACKGROUND

[0002] As a new type of green energy, lithium ion batteries have been rapidly developed and applied in many fields such as automobiles, energy storage, aerospace and handheld electronic devices.

[0003] Lithium precipitation is a common abnormal phenomenon of lithium ion batteries during charging, especially when charging at a large current or at low temperature. The equilibrium potential of lithium precipitation is 0V. During charging, the negative electrode potential decreases due to polarization and lithium intercalation reaction. When the potential of the negative electrode is lower than the electrode potential of lithium, lithium precipitation occurs. After lithium is precipitated on the surface of the negative electrode, part of it will be re-embedded in the negative electrode in the subsequent process, which is called reversible lithium. Another part may lose electrical connection by detaching from the negative electrode surface or reacting with the electrolyte to form byproducts. This part of the precipitated lithium cannot be re-embedded in the negative electrode and is called irreversible lithium or dead lithium. Due to the strong reactivity of lithium and poor thermal stability, it can react with the electrolyte at a low temperature, reducing the safety and stability of the battery. At the same time, the lithium dendrites precipitated may pierce the battery separator and cause positive and negative short circuits, leading to safety accidents. Therefore, to ensure the normal use of the battery system and reduce the safety risk, it is necessary to detect lithium precipitation in a timely manner.

[0004] In related technologies, common lithium precipitation detection methods mainly include scanning electron microscopy and voltage relaxation method. The scanning electron microscope observes the difference in the surface morphology of graphite to determine whether lithium metal is precipitated. The voltage relaxation method uses the principle that the precipitated lithium is re-embedded in graphite, uses differential processing method to obtain the rate of change of voltage with time, and determines whether lithium precipitation occurs in the battery process by the appearance of the differential lithium voltage peak on the curve. The scanning electron microscope is an offline destructive detection method which is not suitable for online detection of the battery system. Although the voltage relaxation method can be used for online detection, its detection sensitivity is low and it can only be detected and recognized when a large amount of lithium precipitation occurs, which has a high risk.

[0005] To solve the above problems, no effective solution has been proposed so far. SUMMARY

[0006] The embodiments of the present application provide a lithium precipitation detection method and device for a battery, a storage medium and a processor to at least solve the technical problem that the lithium precipitation detection method in related technologies is not suitable for online detection and the determination of lithium precipitation is not timely due to poor detection sensitivity, affecting the service life and safety of the battery.

[0007] According to an aspect of the embodiments of the present application, a lithium precipitation detection method of a battery is provided, including: obtaining a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, determining a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; determining a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent a degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; and determining that the battery has lithium precipitation in a case where the capacity change rate is greater than the target reference value.

[0008] Optionally, the capacity change rate of the negative electrode of the battery after the predetermined number of cycles includes: obtaining a first capacity difference of the battery in a first cycle, wherein the first capacity difference is used to indicate a change amount of normal reaction of the negative electrode material; obtaining a second capacity difference of the battery after the predetermined number of cycles, wherein the second capacity difference is used to indicate a change amount of normal reaction of the negative electrode material; and determining the capacity change rate according to the first capacity difference and the second capacity difference.

[0009] Optionally, the first capacity difference of the battery in the first cycle includes: determining a change value of the battery capacity of the battery corresponding to a change of the battery terminal voltage of the battery in the first cycle; obtaining a first function change curve according to the change value of the battery capacity of the battery corresponding to the change of the battery terminal voltage of the battery in the first cycle; performing differential processing on the first function change curve to obtain a second function change curve, and determining a first phase change equilibrium peak and a second phase change equilibrium peak in the second function change curve; obtaining a first capacity value corresponding to the first phase change equilibrium peak and a second capacity value corresponding to the second phase change equilibrium peak; and determining the first capacity difference according to the first capacity value and the second capacity value.

[0010] Optionally, the second capacity difference of the battery after the predetermined number of cycles includes: determining a change value of the battery capacity of the battery corresponding to a change of the battery terminal voltage of the battery after the predetermined number of cycles; obtaining a third function change curve according to the change value of the battery capacity of the battery corresponding to the change of the battery terminal voltage of the battery in the charging process after the predetermined number of cycles; performing differential processing on the third function change curve to obtain a fourth function change curve, and determining a third phase change equilibrium peak and a fourth phase change equilibrium peak in the fourth function change curve; obtaining a third capacity value corresponding to the third phase change equilibrium peak and a fourth capacity value corresponding to the fourth phase change equilibrium peak; and determining the second capacity difference according to the third capacity value and the fourth capacity value.

[0011] Optionally, the capacity change rate is determined according to the first capacity difference and the second capacity difference, including: determining a first ratio of the first capacity difference and the second capacity difference; and determining the first ratio as the capacity change rate.

[0012] Optionally, the target reference value of the battery is determined according to the first available capacity and the second available capacity, including: determining a second ratio of the first available capacity and the second available capacity; and determining the second ratio as the target reference value.

[0013] Optionally, the method further includes: determining that the battery does not have lithium precipitation in a case where the capacity change rate is less than the target reference value.

[0014] According to another aspect of the embodiments of the present application, a lithium precipitation detection device of a battery is also provided, including: an obtaining module, configured to obtain a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, and determine a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; a first determining module, configured to determine a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent a degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; and a second determining module, configured to determine that the battery has lithium precipitation in a case where the capacity change rate is greater than the target reference value.

[0015] According to another aspect of the embodiments of the present application, a non-volatile storage medium is also provided, including a stored program, wherein the non-volatile storage medium controls a device where the non-volatile storage medium is located to execute any one of the lithium precipitation detection methods of the battery when the program is running.

[0016] According to another aspect of the embodiments of the present application, a processor is also provided, and the processor is used to run a program, wherein the processor executes any one of the lithium precipitation detection methods of the battery when the program is running.

[0017] In the embodiment of the present application, the way of detecting the amount of negative material participating in chemical reaction to evaluate whether the battery is lithiumizing is adopted, the first available capacity corresponding to the negative electrode of the battery and the second available capacity corresponding to the positive electrode of the battery are obtained, the target reference value of the battery is determined according to the first available capacity and the second available capacity, wherein the target reference value is used to represent the critical value of lithiumizing of the battery; the capacity change rate of the negative material of the battery after a predetermined number of cycles is determined, wherein the capacity change rate is used to represent the degree of lithiumizing reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithiumizing reaction of the negative electrode; in the case that the capacity change rate is greater than the target reference value, it is determined that the battery is lithiumizing, which achieves the purpose of detecting the capacity change rate to determine whether the battery is lithiumizing, thereby greatly simplifying the steps of lithiumizing detection, timely and accurately discovering that the battery is lithiumizing, and indirectly improving the technical effects of battery life and safety, and solving the technical problems that the lithiumizing detection method in the related art is not suitable for online detection, and the determination of lithiumizing phenomenon is not timely due to poor detection sensitivity, which affects the battery life and safety. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application, the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0019] Figure 1 is a flowchart of a lithiumizing detection method of a battery according to an embodiment of the present application;

[0020] Figure 2 is a dv / dq-q curve diagram in an exemplary embodiment of the present application;

[0021] Figure 3 is a dv / dq-q curve diagram of a certain battery in an exemplary embodiment of the present application during the cycle use;

[0022] Figure 4 is a structural diagram of a lithiumizing detection device of a battery according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application and the above-described accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular sequential or chronological order. It should be understood that the data thus used can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in sequences other than those illustrated or described herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a list of steps or units as processes, methods, systems, products, or apparatuses does not necessarily limit those steps or units to those clearly listed, but can include other steps or units not clearly listed or inherent to such processes, methods, products, or apparatuses.

[0025] According to an embodiment of the present application, an embodiment of a lithium precipitation detection method of a battery is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0026] Figure 1 is a lithium precipitation detection method of a battery according to an embodiment of the present application, as shown in Figure 1 the method comprises the following steps:

[0027] Step S102, acquiring a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, and determining a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery;

[0028] Step S104, determining a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent the degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode;

[0029] Step S106, determining that the battery has lithium precipitation in the case that the capacity change rate is greater than the target reference value.

[0030] The method for detecting lithium precipitation of the battery comprises the following steps: obtaining a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery; determining a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; determining a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles; and determining that lithium precipitation occurs in the battery when the capacity change rate is greater than the target reference value, so as to achieve the purpose of determining whether lithium precipitation occurs in the battery according to the capacity change rate, thereby greatly simplifying the steps of lithium precipitation detection, discovering lithium precipitation of the battery in time and accurately, and indirectly improving the service life and safety of the battery, and solving the technical problems of not timely determining lithium precipitation and affecting the service life and safety of the battery due to poor detection sensitivity of the lithium precipitation detection method in the related art.

[0031] It should be noted that the measurement units of the first available capacity and the second available capacity are ampere-hours (Ah) or milliampere-hours (mAh). Ampere-hours can also be referred to as ampere-hours, which is equal to the current in a period of time. One ampere-hour is equal to one ampere connection current for one hour. Milliampere-hours can also be referred to as milliampere-hours, which is one-thousandth of an ampere-hour, that is, 1000 mAh = 1 Ah.

[0032] In some embodiments of the present application, the capacity change rate of the negative electrode of the battery after a predetermined number of cycles can be achieved by the following steps. Specifically, a first capacity difference in the first cycle is obtained, wherein the first capacity difference is used to indicate the change amount of the normal reaction of the negative electrode material; a second capacity difference after a predetermined number of cycles is obtained, wherein the second capacity difference indicates the change amount of the normal reaction of the negative electrode material; and the capacity change rate is determined according to the first capacity difference and the second capacity difference. It should be noted that the normal reaction of the negative electrode material refers to the chemical reaction between the ions of the positive electrode and the negative electrode material in the normal use process of the battery. For example, when the battery is a lithium battery and the negative electrode material is graphite, the normal reaction refers to the reaction between lithium ions and graphite.

[0033] In some optional embodiments of the present application, the first capacity difference in the first cycle can be achieved by the following method: determining the change value of the battery capacity corresponding to the battery voltage of the battery in the first cycle; obtaining a first function change curve according to the change value of the battery capacity corresponding to the battery voltage of the battery in the first cycle; performing differential processing on the first function change curve to obtain a second function change curve, and determining a first phase change equilibrium peak and a second phase change equilibrium peak in the second function change curve; obtaining a first capacity value corresponding to the first phase change equilibrium peak and a second capacity value corresponding to the second phase change equilibrium peak; and determining the first capacity difference according to the first capacity value and the second capacity value.

[0034] It should be noted that the above-mentioned cycle use process refers to a process of completing a 100% full discharge / charge of the battery, for example, the battery has 100% power, and the power of the battery is used to 0% (i.e. full discharge), and then charged to 100% (i.e. full charge), which is a cycle, at this time, the cycle number of the battery is 1, and the charge number is 1.

[0035] It is easy to note that the above-mentioned first function curve is a v-q curve, and the above-mentioned second function curve is a dv / dq-q (which can also be expressed as dvdq-q) curve, Figure 2 is a dv / dq-q curve diagram in an exemplary embodiment of the present application, as Figure 2 shown, the curve has two obvious convex inflection points, and the two inflection points are two phase transition equilibrium peaks, as Figure 2 shown, peak 1 (i.e. first phase transition equilibrium peak) and peak 2 (i.e. second phase transition equilibrium peak); It should be noted that peak 1 and peak 2 correspond to two characteristic reaction phase transition equilibrium peaks of lithium ions embedded in graphite, so the change of the relative distance between peak 1 and peak 2 represents the change of the amount of graphite participating in the reaction in the cycle process, wherein peak 1 corresponds to a first capacity value, and peak 2 corresponds to a second capacity value, so the first capacity difference can be determined according to the difference between the second capacity value and the first capacity value.

[0036] Similarly, the second capacity difference of the battery after a predetermined number of cycles can be obtained by the following steps, specifically, the change value of the battery capacity corresponding to the battery can be determined as the battery voltage of the battery changes after the battery is used for a predetermined number of cycles; a third function curve is obtained according to the change value of the battery capacity corresponding to the battery as the battery voltage of the battery changes during the charging process of the battery after the battery is used for a predetermined number of cycles; the third function curve is differentiated to obtain a fourth function curve, and the third phase transition equilibrium peak and the fourth phase transition equilibrium peak in the fourth function curve are determined; a third capacity value corresponding to the third phase transition equilibrium peak and a fourth capacity value corresponding to the fourth phase transition equilibrium peak are obtained; and a second capacity difference is determined according to the third capacity value and the fourth capacity value.

[0037] It should be noted that the capacity change rate obtained according to the first capacity difference and the second capacity difference can be a first ratio of the first capacity difference and the second capacity difference; and the first ratio is determined as the capacity change rate.

[0038] In some embodiments of the present application, the target reference value of the battery is determined according to the first available capacity and the second available capacity, which can be a second ratio of the first available capacity and the second available capacity; and the second ratio is determined as the target reference value. It should be noted that in the design process of the battery, in order to prevent lithium precipitation of the negative electrode, the available capacity of the negative electrode (i.e. the first available capacity) is generally greater than the available capacity of the positive electrode (i.e. the second available capacity), so that the first available capacity / second available capacity can obtain the target reference value, and the target reference value N / P is generally between 1.1-1.2.

[0039] It should be noted that with the cyclic use of the battery cell, if it is detected that the amount of negative electrode material participating in the reaction (the negative electrode material includes but is not limited to: graphite) is less and less, the risk of lithium precipitation increases, and when the change rate of the amount of negative electrode participating in the reaction is greater than N / P, lithium precipitation occurs, that is, in the case where the capacity change rate is greater than the target reference value, it can be determined that the battery has lithium precipitation. It can be understood that in the case where the capacity change rate is less than the target reference value, it can be determined that the battery has not lithium precipitation.

[0040] In order to facilitate the understanding of the embodiments of the present application, the present application will be described in conjunction with a specific embodiment, Figure 3 For a battery in an example of the present application, the dv / dq-q curve in the cyclic use process is shown in the following figure, Figure 3 It can be seen from the figure that the distance between peak 1 and peak 2 (i.e. the first capacity difference) q1=5.706 of the fresh battery cell, i.e. the first cycle, and the distance between peak 1' and peak 2' (i.e. the second capacity difference) q1'=4.585 of the battery cell after cycling for several times. This phenomenon shows that the available material of the negative electrode has been reduced after cycling.

[0041] Therefore, by determining the first ratio of the first capacity difference and the second capacity difference, the negative electrode capacity change rate z=q1 / q1'=1.244 can be obtained. Assuming that the target reference value N / P of this battery is 1.13, since the negative electrode change rate z is greater than the target reference value N / P, it can be determined that this battery has lithium precipitation after cycling for several times.

[0042] It should be noted that the difference between the capacity change rate and the target reference value can be used to indicate the degree of lithium precipitation of the battery. The greater the difference between the capacity change rate and the target reference value, the more serious the lithium precipitation of the battery. For example, [0.001-0.05) represents slight lithium precipitation, [0.05-0.09) represents ordinary lithium precipitation, and greater than 0.09 represents serious lithium precipitation. Since the above embodiment 1.244-1.13=0.114, it can be determined that the battery has serious lithium precipitation.

[0043] Figure 4 According to the lithium precipitation detection device of a battery according to an embodiment of the present application, as shown in Figure 4 The device comprises:

[0044] The acquisition module 40 is configured to acquire a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, and determine a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery.

[0045] The first determination module 42 is configured to determine a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent a degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode.

[0046] The second determination module 44 is configured to determine that the battery has lithium precipitation when the capacity change rate is greater than the target reference value.

[0047] In the lithium precipitation detection device of the battery, the acquisition module 40 is configured to acquire a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, and determine a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; the first determination module 42 is configured to determine a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles; and the second determination module 44 is configured to determine that the battery has lithium precipitation when the capacity change rate is greater than the target reference value, so as to achieve the purpose of online detection of the capacity change rate and determination of whether the battery has lithium precipitation, thereby greatly simplifying the steps of lithium precipitation detection, timely and accurately discovering lithium precipitation of the battery, and indirectly improving the service life and safety of the battery, and thereby solving the technical problems of untimely determination of lithium precipitation phenomenon and influence on the service life and safety of the battery caused by the poor detection sensitivity of the lithium precipitation detection method in the related art.

[0048] According to another aspect of the embodiments of the present application, a non-volatile storage medium is also provided, which includes a stored program, wherein the program, when executed, controls a device in which the non-volatile storage medium is located to perform any one of the lithium precipitation detection methods of the battery.

[0049] According to another aspect of the embodiments of the present application, a processor is also provided, which is used to execute a program, wherein the program, when executed, performs any one of the lithium precipitation detection methods of the battery.

[0050] Specifically, the storage medium is used to store program instructions for executing the following functions, and the following functions are implemented:

[0051] acquire a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, determine a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; determine a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent a degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; and determine that the battery has lithium precipitation in a case where the capacity change rate is greater than the target reference value.

[0052] Specifically, the processor is configured to invoke program instructions in the memory to implement the following functions:

[0053] acquire a first available capacity corresponding to a negative electrode of the battery and a second available capacity corresponding to a positive electrode of the battery, determine a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; determine a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent a degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; and determine that the battery has lithium precipitation in a case where the capacity change rate is greater than the target reference value.

[0054] In the related embodiments of the present application, the method for evaluating whether the battery has lithium precipitation by detecting the amount of negative electrode material participating in the chemical reaction in real time is adopted, the first available capacity corresponding to the negative electrode of the battery and the second available capacity corresponding to the positive electrode of the battery are acquired, the target reference value of the battery is determined according to the first available capacity and the second available capacity, wherein the target reference value is used to represent the critical value of lithium precipitation of the battery; the capacity change rate of the negative electrode material of the battery after a predetermined number of cycles is determined, wherein the capacity change rate is used to represent the degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; and it is determined that the battery has lithium precipitation in a case where the capacity change rate is greater than the target reference value, thereby achieving the purpose of determining whether the battery has lithium precipitation by detecting the capacity change rate in real time, greatly simplifying the steps of lithium precipitation detection, discovering lithium precipitation of the battery in time and accurately, and indirectly improving the service life and safety of the battery, thereby solving the technical problems that the lithium precipitation detection method in the related art is not suitable for online detection, the detection sensitivity is poor, the lithium precipitation phenomenon is not determined in time, and the service life and safety of the battery are affected.

[0055] The sequence numbers of the above embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0056] In the above embodiments of the present application, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0057] In several embodiments provided in the present application, it should be understood that the disclosed technology can be implemented by other ways. Among them, the above-described device embodiments are only schematic, for example, the division of the units can be a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, units or modules, and can be electrical or other forms.

[0058] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. can be located in one place or can be distributed to multiple units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0059] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0060] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a plurality of instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and various program codes that can be stored in the medium.

[0061] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A lithium precipitation detection method of a battery, characterized by, The method comprises the following steps: obtaining a first available capacity corresponding to a negative electrode of a battery and a second available capacity corresponding to a positive electrode of the battery, and determining a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; determining a capacity change rate of the negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent the degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; determining that the battery has lithium precipitation when the capacity change rate is greater than the target reference value; determining the capacity change rate of the negative electrode material of the battery after a predetermined number of cycles comprises: obtaining a first capacity difference of the battery during the first cycle, wherein the first capacity difference is used to indicate the change amount of the normal reaction of the negative electrode material; obtaining a second capacity difference of the battery after the predetermined number of cycles, wherein the second capacity difference indicates the change amount of the normal reaction of the negative electrode material; and determining the capacity change rate according to the first capacity difference and the second capacity difference.

2. The method of claim 1, wherein, obtaining the first capacity difference of the battery during the first cycle comprises: determining the change value of the battery capacity of the battery with the increase of the battery terminal voltage of the battery during the first cycle; obtaining a first function change curve according to the change value of the battery capacity of the battery with the increase of the battery terminal voltage of the battery during the first cycle; determining a first phase change equilibrium peak and a second phase change equilibrium peak in a second function change curve obtained by differentiating the first function change curve, wherein the first phase change equilibrium peak and the second phase change equilibrium peak represent the peak points of the curve in the second function change curve; obtaining a first capacity value corresponding to the first phase change equilibrium peak and a second capacity value corresponding to the second phase change equilibrium peak; determining the first capacity difference according to the first capacity value and the second capacity value.

3. The method of claim 1, wherein, obtaining the second capacity difference of the battery after the predetermined number of cycles comprises: determining the change value of the battery capacity of the battery with the increase of the battery terminal voltage of the battery after the predetermined number of cycles; obtaining a third function change curve according to the change value of the battery capacity of the battery with the increase of the battery terminal voltage of the battery during the charging process of the battery after the predetermined number of cycles; determining a third phase change equilibrium peak and a fourth phase change equilibrium peak in a fourth function change curve obtained by differentiating the third function change curve, wherein the third phase change equilibrium peak and the fourth phase change equilibrium peak represent the peak points of the curve in the fourth function change curve; obtaining a third capacity value corresponding to the third phase change equilibrium peak and a fourth capacity value corresponding to the fourth phase change equilibrium peak; determining the second capacity difference according to the first capacity difference and the second capacity difference, comprising:

4. The method of claim 1, wherein, determining a first ratio of the first capacity difference and the second capacity difference; determining the first ratio as the capacity change rate. determining a second ratio of the first available capacity and the second available capacity; 5. The method of claim 1, wherein, determining the second ratio as the target reference value. The method further comprises: in a case where the capacity change rate is less than the target reference value, determining that the battery does not occur lithium precipitation. comprising:

6. The method of claim 1, wherein, an acquisition module, configured to acquire a first available capacity corresponding to a negative electrode of a battery and a second available capacity corresponding to a positive electrode of the battery, and determine a target reference value of the battery according to the first available capacity and the second available capacity, wherein the target reference value is used to represent a critical value of lithium precipitation of the battery; 7. A lithium precipitation detection device of a battery, characterized by, a first determination module, configured to determine a capacity change rate of a negative electrode material of the battery after a predetermined number of cycles, wherein the capacity change rate is used to represent a degree of lithium precipitation reaction of the negative electrode, and the greater the capacity change rate, the greater the degree of lithium precipitation reaction of the negative electrode; a second determination module, configured to determine that the battery occurs lithium precipitation in a case where the capacity change rate is greater than the target reference value. determining the capacity change rate of the negative electrode of the battery after the predetermined number of cycles, comprising: acquiring a first capacity difference of the battery in a first cycle, wherein the first capacity difference is used to indicate a change amount of normal reaction of the negative electrode material; acquiring a second capacity difference of the battery after the predetermined number of cycles, wherein the second capacity difference is used to indicate the change amount of normal reaction of the negative electrode material; and determining the capacity change rate according to the first capacity difference and the second capacity difference. The non-volatile storage medium comprises a stored program, wherein when the program runs, the device in which the non-volatile storage medium is located is controlled to execute the lithium precipitation detection method of the battery in any one of claims 1 to 6. The processor is used to run a program, wherein when the program runs, the lithium precipitation detection method of the battery in any one of claims 1 to 6 is executed.

8. A non-volatile storage medium, comprising: ​ 9. A processor, comprising: ​

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