Lithium ion battery positive electrode sheet, charging voltage control method of lithium ion battery

Abstract

The present application discloses a lithium-ion battery positive electrode plate and a charging voltage control method for a lithium-ion battery, which relates to the technical field of lithium-ion batteries. The main purpose is to extend the service life of lithium-ion batteries while reducing the amount of negative electrode materials used in lithium-ion batteries; the main technical scheme includes: the positive electrode plate of the lithium-ion battery includes at least two positive electrode materials, each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage. Determine the positive electrode material of the lithium-ion battery that is currently to release active lithium; monitor the battery health status value of the lithium-ion battery; when the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, set the charging voltage of the lithium-ion battery to the target charging voltage corresponding to the positive electrode material of the current active lithium to be released.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and in particular to a positive electrode plate of a lithium-ion battery and a charging voltage control method of a lithium-ion battery. Background Art

[0002] Lithium-ion batteries have become a commonly used power source in electronic communications, transportation, aviation and other fields due to their advantages such as high energy density, high safety and long cycle life.

[0003] The life of a lithium-ion battery is limited by the active lithium provided by its own positive electrode material. Therefore, in order to obtain a lithium-ion battery with a longer life, the amount of positive electrode material that provides active lithium is usually increased. Correspondingly, while increasing the amount of positive electrode material used, the amount of negative electrode material that serves as a carrier of active lithium and electrons and plays a role in energy storage and release will also be increased. However, in order to prevent lithium deposition in lithium-ion batteries, the amount of lithium that can be embedded in the negative electrode of the battery is often greater than the amount of lithium that can be removed from the positive electrode, resulting in a portion of the negative electrode material being unable to function, causing a huge waste of negative electrode materials. Summary of the invention

[0004] In view of this, the present application proposes a lithium-ion battery positive electrode plate and a charging voltage control method for a lithium-ion battery, the main purpose of which is to extend the service life of the lithium-ion battery while reducing the amount of negative electrode material used in the lithium-ion battery.

[0005] In a first aspect, the present application provides a lithium-ion battery positive electrode plate, which includes: at least two positive electrode materials, wherein each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage.

[0006] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. The lithium-ion battery with such a positive electrode plate of the lithium-ion battery has the ability to release active lithium in steps. The active lithium of the positive electrode plate of such a lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equivalent to the total amount of all positive electrode materials used, and the amount used can be matched with the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided in the present application can extend the service life of the lithium-ion battery while reducing the amount of negative electrode material used in the lithium-ion battery.

[0007] In some embodiments, each of the positive electrode materials has its own corresponding charging platform voltage, and the charging platform voltage of each of the positive electrode materials defines the active lithium release order of each of the positive electrode materials. For any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the latter order is greater than the charging platform voltage of the positive electrode material in the former order. The active lithium release order of various positive electrode materials is set based on the size of the charging platform voltage, which can avoid positive electrode materials with different target charging voltages from releasing active lithium at the same time, thereby avoiding lithium plating in lithium-ion batteries.

[0008] In some embodiments, for any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the later positive electrode material is any voltage between the charging platform voltages of the two adjacent positive electrode materials. This setting method of the target charging voltage can, when the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the later positive electrode material, both stimulate the later positive electrode material to release active lithium to restore the battery capacity of the lithium-ion battery and ensure that the earlier positive electrode material does not undergo a serious phase change.

[0009] In some embodiments, for any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the positive electrode material in the later sequence is the voltage corresponding to the point with the maximum slope in the curve between the two target points, wherein the two target points are points corresponding to their respective charging platform voltages in the relationship curve between the charging voltage and the state of charge of the lithium-ion battery where the positive electrode plate of the lithium-ion battery is located. Where the slope of the curve between the two target points increases, the charging voltage increases slightly, and the change in the state of charge is relatively small, that is, where the slope is large, the change in the state of charge is relatively slow. Therefore, relatively speaking, the state of charge error caused by the voltage error is very small. Therefore, in order to reduce the error, the target charging voltage corresponding to the positive electrode material in the later sequence is the voltage corresponding to the point with the maximum slope in the curve between the two target points.

[0010] In some embodiments, the lithium-ion battery positive electrode plate includes the following two positive electrode materials: a first material and a second material, wherein the charging platform voltage of the second material is greater than the charging platform voltage of the first material;

[0011] The proportion of the second material in the first material and the second material is any value within a first numerical range, wherein the values ​​in the first numerical range are used to limit the active lithium released by the second material at its corresponding target charging voltage to at least restore the capacity of the lithium-ion battery to a first preset battery capacity, and the released active lithium will not cause lithium deposition in the lithium-ion battery.

[0012] In some embodiments, the lower limit of the first numerical range is a value not less than 3%, and the upper limit is a value not greater than 50%. The proportion of the second material in the first material and the second material is any value within the first numerical range, which can ensure that the active lithium released by the second material at its corresponding target charging voltage at least restores the capacity of the lithium-ion battery to the first preset battery capacity, and the released active lithium does not cause lithium deposition in the lithium-ion battery.

[0013] In some embodiments, the first material is any one of the following materials: LiFePO4, LiCoO2, LiNiO2, LiMn2O4, LiNi 0.5 Mn 1.5 O4, nickel-cobalt-manganese ternary materials.

[0014] In some embodiments, the second material is any one of the following materials: LiFePO4, LiCoO2, LiNiO2, LiMn2O4, LiNi 0.5 Mn 1.5 O4, nickel-cobalt-manganese ternary materials.

[0015] In a second aspect, the present application provides a charging voltage control method for a lithium-ion battery, wherein the positive electrode sheet of the lithium-ion battery includes at least two positive electrode materials, each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage, and the method includes:

[0016] Determining the positive electrode material currently to release active lithium in the lithium-ion battery;

[0017] Monitoring the battery health status value of the lithium-ion battery;

[0018] When the battery health state value of the lithium ion battery is not greater than the battery health state threshold, the charging voltage of the lithium ion battery is set to a target charging voltage corresponding to the positive electrode material currently to release active lithium.

[0019] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. When the lithium-ion battery is put into use, the battery health status value of the lithium-ion battery is monitored. Once the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the current active lithium to be released, so that the positive electrode material of the current active lithium to be released releases active lithium at the target charging voltage to replenish the capacity of the lithium-ion battery. It can be seen that by setting the target charging voltage, the positive electrode plate of the lithium-ion battery releases active lithium in steps. The active lithium of the positive electrode plate of this lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equal to the total amount of all positive electrode materials used, and the amount used can match the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided by the present application can extend the service life of lithium-ion batteries while reducing the amount of negative electrode materials used in lithium-ion batteries.

[0020] In some embodiments, the method further comprises:

[0021] Obtaining a charging platform voltage of each of the positive electrode materials;

[0022] The active lithium release order of each positive electrode material is set according to the charging platform voltage of each positive electrode material, wherein, for any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the latter order is greater than the charging platform voltage of the positive electrode material in the former order. The active lithium release order of various positive electrode materials is set based on the charging platform voltage, which can avoid positive electrode materials with different target charging voltages from releasing active lithium at the same time, thereby avoiding lithium plating in lithium-ion batteries.

[0023] In some embodiments, determining the positive electrode material currently to release active lithium in the lithium-ion battery comprises:

[0024] When the target charging voltage of any of the positive electrode materials is set, the positive electrode material immediately following it is determined as the positive electrode material to be currently releasing active lithium, so that multiple positive electrode materials can be prevented from releasing active lithium at the same time, thereby preventing lithium deposition in the lithium-ion battery.

[0025] In some embodiments, the method further comprises:

[0026] For any two adjacent positive electrode materials in the active lithium release sequence: the target charging voltage corresponding to the later positive electrode material is set to any voltage between the charging platform voltages of the two adjacent positive electrode materials. This setting method of the target charging voltage can stimulate the later positive electrode material to release active lithium to restore the battery capacity of the lithium ion battery when the charging voltage of the lithium ion battery is set to the target charging voltage corresponding to the later positive electrode material, and can also ensure that the earlier positive electrode material does not undergo a serious phase change.

[0027] In some embodiments, the method further includes: for any two adjacent positive electrode materials in the active lithium release sequence: obtaining the target point corresponding to the charging platform voltage of the two adjacent positive electrode materials in the relationship curve between the charging voltage and the state of charge of the lithium-ion battery; determining the target charging voltage corresponding to the positive electrode material in the later sequence as the voltage corresponding to the point with the maximum slope in the curve between the two target points. Where the slope of the curve between the two target points increases, the charging voltage increases slightly, and the change in the state of charge is relatively small, that is, where the slope is large, the change in the state of charge is relatively slow. Therefore, the state of charge error caused by the voltage error is relatively small. Therefore, in order to reduce the error, the target charging voltage corresponding to the positive electrode material in the later sequence is the voltage corresponding to the point with the maximum slope in the curve between the two target points.

[0028] In some embodiments, the method further comprises:

[0029] A battery health status threshold value corresponding to the positive electrode material currently to release active lithium is selected, wherein the battery health status threshold value is any value within a second numerical range, wherein the values ​​in the second numerical range are used to limit that when the capacity of the lithium-ion battery reaches a second preset battery capacity that cannot supply power normally, the active lithium released by the positive electrode material currently to release active lithium at least restores the capacity of the lithium-ion battery to a third preset battery capacity, and the released active lithium does not cause lithium deposition in the lithium-ion battery.

[0030] In some embodiments, the method further comprises:

[0031] Setting the battery health status value corresponding to the lithium-ion battery capacity reaching the lower limit value at which the battery cannot supply power normally as the lower limit value of the second value interval;

[0032] The upper limit of the second numerical range is set based on the lithium replenishment ratio of the positive electrode material to be currently released active lithium. The battery health status threshold is any value within the second numerical range, which can ensure that when the capacity of the lithium-ion battery reaches the second preset battery capacity that cannot supply power normally, the active lithium released by the positive electrode material to be currently released active lithium at least restores the capacity of the lithium-ion battery to the third preset battery capacity, and the released active lithium will not cause lithium deposition in the lithium-ion battery.

[0033] In some embodiments, after setting the charging voltage of the lithium-ion battery to a target charging voltage corresponding to the positive electrode material currently to release active lithium, the method further includes:

[0034] When the capacity of the lithium-ion battery is monitored to be the fourth preset battery capacity, the charging voltage of the lithium-ion battery is set to any value within the charging voltage range, wherein the lower limit of the charging voltage range is greater than or equal to the lower limit charging voltage of the first positive electrode material to release lithium ions in the active lithium release sequence, and the upper limit is not greater than the upper limit charging voltage of the positive electrode material to be currently released active lithium, and is less than the target charging voltage corresponding to the positive electrode material immediately following the positive electrode material to be currently released active lithium. When the capacity of the lithium-ion battery is restored, a charging voltage suitable for charging the lithium-ion battery is set to facilitate charging of the lithium-ion battery.

[0035] In some embodiments, monitoring the battery health status value of the lithium-ion battery includes: monitoring the battery health status value of the lithium-ion battery at a preset frequency, so as to timely detect the situation that the active lithium in the lithium-ion battery has been consumed to the extent that the normal power supply of the lithium-ion battery is affected.

[0036] In some embodiments, monitoring the battery health status value of the lithium-ion battery includes: when receiving a monitoring instruction to monitor the battery health status value, monitoring the battery health status value of the lithium-ion battery. This is applicable to scenarios where the user actively initiates battery health status value monitoring when the user finds that the power supply of the lithium-ion battery is insufficient and suspects that the active lithium of the lithium-ion battery is consumed too much, thereby enhancing the flexibility of battery monitoring status value monitoring.

[0037] In some embodiments, monitoring the battery health status value of the lithium-ion battery includes: when the lithium-ion battery is detected to be in a charging state, monitoring the battery health status value of the lithium-ion battery. In the charging state of the lithium-ion battery, once the battery health status value is detected to be abnormal, the charging voltage of the lithium-ion battery can be set in time to a target charging voltage corresponding to the positive electrode material of the current active lithium to be released, so that the positive electrode material of the current active lithium to be released releases the active lithium for restoring the battery capacity.

[0038] In a third aspect, the present application provides a battery management system, wherein the positive electrode sheet of the lithium-ion battery includes at least two positive electrode materials, each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage, and the battery management system includes:

[0039] A determination unit, used to determine the positive electrode material currently to release active lithium in the lithium-ion battery;

[0040] A monitoring unit, used to monitor the battery health status value of the lithium-ion battery;

[0041] A setting unit is used for setting the charging voltage of the lithium ion battery to a target charging voltage corresponding to the positive electrode material currently to release active lithium when the battery health state value of the lithium ion battery is not greater than a battery health state threshold.

[0042] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. When the lithium-ion battery is put into use, the battery health status value of the lithium-ion battery is monitored. Once the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the current active lithium to be released, so that the positive electrode material of the current active lithium to be released releases active lithium at the target charging voltage to replenish the capacity of the lithium-ion battery. It can be seen that by setting the target charging voltage, the positive electrode plate of the lithium-ion battery releases active lithium in steps. The active lithium of the positive electrode plate of this lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equal to the total amount of all positive electrode materials used, and the amount used can match the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided by the present application can extend the service life of lithium-ion batteries while reducing the amount of negative electrode materials used in lithium-ion batteries.

[0043] In a fourth aspect, the present application provides a lithium-ion battery, comprising: the lithium-ion battery positive electrode sheet described in the first aspect.

[0044] In some embodiments, the lithium-ion battery further includes: a battery management system as described in the third aspect.

[0045] In some embodiments, the ratio of the negative electrode capacity to the positive electrode capacity of the lithium-ion battery is any value in a third numerical range, the lower limit of the third numerical range is a value not less than 0.67, and the upper limit is a value not greater than 1.

[0046] In a fifth aspect, the present application provides an electrical device, characterized in that the electrical device comprises a lithium-ion battery as described in the fourth aspect, and the lithium-ion battery is used to provide electrical energy.

[0047] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 A flow chart of a method for controlling charging voltage of a lithium-ion battery provided by an embodiment of the present application is shown;

[0050] Figure 2 A flow chart showing a method for controlling charging voltage of a lithium-ion battery provided by another embodiment of the present application is shown;

[0051] Figure 3 A schematic diagram of a curve showing the relationship between a charging voltage and a state of charge provided by an embodiment of the present application is shown;

[0052] Figure 4 A schematic diagram of a curve showing the relationship between a charging voltage and a state of charge provided by another embodiment of the present application is shown;

[0053] Figure 5 A schematic diagram of a curve showing the relationship between a charging voltage and a state of charge provided by another embodiment of the present application is shown;

[0054] Figure 6 A schematic diagram of a relationship curve between a battery health status value and a battery cycle number provided in another embodiment of the present application is shown;

[0055] Figure 7 A schematic diagram of a battery management system provided by an embodiment of the present application is shown;

[0056] Figure 8 A schematic diagram of a battery management system provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0057] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0059] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0060] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0061] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0062] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0063] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0064] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0065] At present, lithium-ion batteries have become a major power source due to their outstanding advantages such as high energy density, high safety and long cycle life. They are widely used in many fields such as electronic communications, transportation, aviation and home energy storage.

[0066] The life of a lithium-ion battery is limited by the active lithium provided by its own positive electrode material. Its own active lithium will be continuously consumed as the lithium-ion battery is used, and its life will also decrease as the active lithium is consumed.

[0067] The inventors have noticed that in order to obtain a lithium-ion battery with a longer life, the amount of positive electrode material that provides active lithium is usually increased. Correspondingly, while increasing the amount of positive electrode material used, the amount of negative electrode material that serves as a carrier of active lithium and electrons and plays a role in energy storage and release will also be increased. With the use of lithium-ion batteries, the active lithium provided by the positive electrode material is continuously consumed, and with the consumption of active lithium, the negative electrode material will be in excess. In order to prevent lithium deposition in lithium-ion batteries when designing lithium-ion batteries, the amount of lithium that can be embedded in the negative electrode is greater than the amount of lithium that can be removed from the positive electrode. Therefore, when the lithium-ion battery ends its life and is scrapped, there is still a large amount of negative electrode material inside it that can play a role in energy storage and release. It can be seen that this method of increasing the amount of positive electrode material used to obtain a long-life lithium-ion battery causes a great waste of negative electrode materials.

[0068] In order to solve the problem of waste of negative electrode materials, the inventors have discovered that a lithium-ion battery positive electrode sheet with the ability to release active lithium in steps can be designed for lithium-ion batteries. In a lithium-ion battery with such a lithium-ion battery positive electrode sheet, the amount of negative electrode material used can be matched with the active lithium released by the positive electrode sheet in each step, thereby reducing the amount of negative electrode material used.

[0069] Based on the above considerations, in order to extend the service life of lithium-ion batteries while reducing the use of negative electrode materials of lithium-ion batteries, the inventors have designed a lithium-ion battery positive electrode plate after in-depth research. This lithium-ion battery positive electrode plate includes at least two positive electrode materials, wherein each positive electrode material has its own corresponding target charging voltage, and each positive electrode material releases active lithium at its corresponding target charging voltage.

[0070] The lithium-ion battery with this positive electrode sheet has the ability to release active lithium in steps. The active lithium in the positive electrode sheet of this lithium-ion battery is not released all at once, but when the active lithium currently in the lithium-ion battery decays to the point where it affects the normal use of the battery, the positive electrode sheet is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equal to the total amount of all positive electrode materials used, and the amount used can match the active lithium released by the positive electrode sheet in each step, thereby reducing the amount of negative electrode material used.

[0071] In order to realize the step-by-step release of active lithium in the positive electrode sheet of a lithium-ion battery, the inventors have designed, after in-depth research, a charging voltage control method for a lithium-ion battery having the above-mentioned positive electrode sheet of a lithium-ion battery, so that when the battery health state value of the lithium-ion battery is not greater than the battery health state threshold, the charging voltage of the lithium-ion battery is set to a target charging voltage corresponding to the positive electrode material of the current active lithium to be released in the lithium-ion positive electrode sheet, so as to stimulate the positive electrode material of the current active lithium to be released to release active lithium, replenish the active lithium consumed in the lithium-ion battery, and restore the battery capacity of the lithium-ion battery.

[0072] The lithium-ion battery with the above-mentioned lithium-ion positive electrode plate, under the control of the above-mentioned lithium-ion battery charging voltage control method, as the lithium-ion battery is cyclically charged and used, once the active lithium currently in the lithium-ion battery is monitored to decay to the point where it affects the normal use of the lithium-ion battery, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the lithium-ion positive electrode plate that is currently to release the active lithium. In this way, when the lithium-ion battery is charged at the target charging voltage, the positive electrode material of the current active lithium to be released is stimulated to release the active lithium, replenish the active lithium consumed in the lithium-ion battery, and restore the battery capacity of the lithium-ion battery. Since the various positive electrode materials in the lithium-ion battery positive electrode plate release the active lithium in steps based on the set charging voltage, the amount of negative electrode material used in the lithium-ion battery with such a positive electrode plate can match the active lithium released by the positive electrode plate in each step, so that the use of negative electrode materials in the lithium-ion battery can be reduced while extending the service life of the lithium-ion battery.

[0073] The lithium-ion battery having the lithium-ion battery positive electrode plate disclosed in the embodiment of the present application can be used, but not limited to, as a power supply for multiple electrical devices such as electronic communications, transportation, aviation, and household energy storage. When the lithium-ion battery is used as an electrical device, in combination with the charging voltage control method of the lithium-ion battery disclosed in the embodiment of the present application, when the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the current active lithium to be released in the lithium-ion positive electrode plate. When the lithium-ion battery is charged at the target charging voltage, the positive electrode material of the current active lithium to be released is stimulated to release active lithium, replenish the active lithium consumed in the lithium-ion battery, and restore the battery capacity of the lithium-ion battery, thereby extending the service life of the lithium-ion battery.

[0074] The present application discloses an electric device including the above-mentioned lithium-ion battery, which may be, but not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0075] The following is a description of the lithium-ion battery positive electrode sheet, the lithium-ion battery charging voltage control method, the lithium-ion battery charging voltage control device, the lithium-ion battery and the power-consuming device provided in the embodiments of the present application.

[0076] An embodiment of the present application provides a lithium-ion battery positive electrode plate, which includes: at least two positive electrode materials, wherein each positive electrode material has its own corresponding target charging voltage, and each positive electrode material releases active lithium at its corresponding target charging voltage.

[0077] In order to achieve the step-by-step release of active lithium in lithium-ion batteries, the principle for selecting positive electrode materials is: select two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. There are three corresponding relationships between positive electrode materials and target charging voltages: The first is that the positive electrode plate of the lithium-ion battery includes two positive electrode materials. In order to achieve the step-by-step release of active lithium, one positive electrode material corresponds to one target charging voltage, and the target charging voltages of the two positive electrode materials are different. The second is that the positive electrode plate of the lithium-ion battery includes more than two positive electrode materials. In order to achieve the distributed release of active lithium, each positive electrode material corresponds to a target charging voltage, and the target charging voltages of various positive electrode materials are different. The third is that the positive electrode plate of the lithium-ion battery includes more than two positive electrode materials, and the target charging voltages involved in various positive electrode materials are two or more, that is, there are two or more positive electrode materials corresponding to one target charging voltage. Exemplarily, the lithium-ion positive electrode plate includes the following three positive electrode materials: positive electrode material A, positive electrode material B and positive electrode material C, wherein positive electrode material A and positive electrode material B correspond to the same target charging voltage 1, positive electrode material C corresponds to a target charging voltage 2, and target charging voltage 1 is different from target charging voltage 2. This is suitable for situations where there are two or more positive electrode materials that need to release active lithium synchronously when active lithium is released in steps.

[0078] Each positive electrode material has its own corresponding charging platform voltage, and the charging platform voltage of each positive electrode material defines the release order of active lithium of each positive electrode material. The charging platform voltage is the ratio of the charging energy to the charging capacity of the corresponding positive electrode material at a set rate. The set rate can be determined based on business needs, and it can be any of the following: not limited to 0.1C, 0.2C, 0.33C, 0.5C, 1C, 2C. For example, the set rate is selected as 0.33C.

[0079] The order of active lithium release is determined according to the magnitude of the charging platform voltage of each positive electrode material, wherein, for any two adjacent positive electrode materials in the order of active lithium release, the charging platform voltage of the positive electrode material in the later order is greater than the charging platform voltage of the positive electrode material in the earlier order. In other words, the positive electrode material corresponding to the smaller charging platform voltage releases active lithium first, while the positive electrode material corresponding to the larger charging platform voltage releases active lithium later.

[0080] The following is an explanation of the method for determining the target charging voltage of each positive electrode material. The method includes the following two methods:

[0081] The first one is that for any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the positive electrode material in the latter sequence is any voltage between the charging platform voltages of the two adjacent positive electrode materials.

[0082] Each positive electrode material has its own corresponding charging platform voltage, and the charging platform voltage of the positive electrode material is used as a basis for determining the target charging voltage of the positive electrode material.

[0083] For any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the later positive electrode material is any voltage between the charging platform voltages of the two adjacent positive electrode materials. The purpose of setting the target charging voltage corresponding to the later positive electrode material to any voltage between the charging platform voltages of the two adjacent positive electrode materials is that when the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the later positive electrode material, the later positive electrode material can be stimulated to release active lithium to restore the battery capacity of the lithium-ion battery, and the positive electrode material in the front sequence can be ensured not to undergo a serious phase change.

[0084] The second type is that for any two adjacent positive electrode materials in the order of active lithium release, the target charging voltage corresponding to the positive electrode material in the later order is the voltage corresponding to the point with the largest slope in the curve between the two target points, wherein the two target points are respectively the points corresponding to their respective charging platform voltages in the curve of the relationship between the charging voltage and the state of charge of the lithium-ion battery where the positive electrode plate of the lithium-ion battery is located.

[0085] First, determine the relationship curve between the charging voltage and the state of charge of the lithium-ion battery where the positive electrode plate of the lithium-ion battery is located. The relationship curve is a curve in the coordinate system where the horizontal axis is the state of charge and the vertical axis is the charging voltage. The relationship curve reflects the situation that the state of charge changes with the charging voltage. The points corresponding to the charging platform voltages of the two adjacent positive electrode materials in the relationship curve are the target points, and the voltage range corresponding to the curve between the two target points in the relationship curve is the selection range of the target charging voltage corresponding to the positive electrode material in the later order. In this voltage range, the charging voltage corresponding to the relatively small slope, the state of charge changes greatly when the charging voltage increases slightly, that is, the state of charge changes quickly in the place with a small slope, and the impact of the voltage error is very large at this time. The charging voltage corresponding to the place with a large slope, the charging voltage increases slightly, and the state of charge changes relatively small, that is, the state of charge changes relatively slowly in the place with a large slope. Therefore, the state of charge error caused by the voltage error is relatively small. Therefore, the target charging voltage corresponding to the positive electrode material in the later order is the voltage corresponding to the point with the largest slope in the curve between the two target points.

[0086] The positive electrode material is only one component of the positive electrode sheet of a lithium-ion battery. The following is an explanation of the preparation process of a lithium-ion battery positive electrode sheet comprising at least two positive electrode materials. The preparation process is as follows: various positive electrode materials can be stirred in a conventional positive electrode slurry stirring manner, and then the mixed slurry obtained by stirring is coated on the surface of an aluminum foil, and after drying, cold pressing, and cutting, a lithium-ion battery positive electrode sheet is formed.

[0087] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. The lithium-ion battery with such a positive electrode plate of the lithium-ion battery has the ability to release active lithium in steps. The active lithium of the positive electrode plate of such a lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equivalent to the total amount of all positive electrode materials used, and the amount used can be matched with the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided in the present application can extend the service life of the lithium-ion battery while reducing the amount of negative electrode material used in the lithium-ion battery.

[0088] An embodiment of the present application provides a lithium-ion battery positive electrode plate, which includes the following two positive electrode materials: a first material and a second material, wherein the charging platform voltage of the second material is greater than the charging platform voltage of the first material.

[0089] The charging platform voltage of the second material is greater than the charging platform voltage of the first material, and optionally, the difference between the two charging platform voltages is greater than 0.1 V. The target charging voltage of the second material is any voltage between the charging platform voltage of the first material and the charging platform voltage of the second material.

[0090] In order to ensure that the active lithium released by the second material at its corresponding target charging voltage at least restores the capacity of the lithium-ion battery to the first preset battery capacity, and the released active lithium does not cause lithium deposition in the lithium-ion battery, the proportion of the second material in the first material and the second material is any value within the first numerical range. The first preset battery capacity is not less than the minimum battery capacity required for the lithium-ion battery to work normally.

[0091] The values ​​in the first numerical range are used to limit the active lithium released by the second material at the corresponding target charging voltage to at least restore the capacity of the lithium-ion battery to the first preset battery capacity, and the released active lithium will not cause lithium deposition in the lithium-ion battery. Optionally, the lower limit of the first numerical range is a value not less than 3%, and the upper limit is a value not greater than 50%.

[0092] The specific material categories of the first material and the second material can be determined based on business requirements. Optionally, the first material is any one of the following materials: LiFePO4, LiCoO2, LiNiO2, LiMn2O4, LiNi 0.5 Mn 1.5 O4, nickel-cobalt-manganese ternary material (LiNi1-xCoxMnyO2). The second material is any one of the following materials: LiFePO4, LiCoO2, LiNiO2, LiMn2O4, LiNi 0.5 Mn 1.5 O4, nickel-cobalt-manganese ternary material (LiNi1-xCoxMnyO2).

[0093] Exemplarily, the first material is LiFePO4, and the second material is a nickel-cobalt-manganese ternary material.

[0094] The present application embodiment provides a method for controlling the charging voltage of a lithium-ion battery. The method is used to control the charging voltage of a lithium-ion battery. The lithium-ion battery involved here has a positive electrode sheet comprising at least two positive electrode materials, each of which has its own corresponding target charging voltage, and each of which releases active lithium at its corresponding target charging voltage. Figure 1 As shown, the charging voltage control method of the lithium-ion battery mainly includes the following steps:

[0095] 101. Determine the positive electrode material in the lithium-ion battery that is currently releasing active lithium.

[0096] In order to prevent positive electrode materials with different target charging voltages from releasing active lithium at the same time, resulting in lithium ion precipitation, it is necessary to obtain the charging platform voltage of each positive electrode material, and then set the active lithium release order of each positive electrode material according to the charging platform voltage of each positive electrode material. The active lithium release order is determined according to the size of the charging platform voltage of each positive electrode material, wherein, for any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the later order is greater than the charging platform voltage of the positive electrode material in the earlier order.

[0097] The charging voltage of the lithium-ion battery is controlled according to the release order of active lithium to ensure that when the charging voltage of the lithium-ion battery is set to the target charging voltage of a positive electrode material, the release order of active lithium is located before it, that is, the positive electrode material whose target charging voltage is less than its target charging voltage has been stimulated to release active lithium.

[0098] When the target charging voltage of any positive electrode material is set, it means that when charging the lithium-ion battery, it will release active lithium for restoring the capacity of the lithium-ion battery. If the lithium-ion battery needs to be supplemented with active lithium again, the positive electrode material immediately following it needs to release active lithium, so the positive electrode material immediately following it is determined as the positive electrode material currently to release active lithium. When the lithium-ion battery needs to be supplemented with active lithium again, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material currently to release active lithium, so that the positive electrode material currently to release active lithium releases active lithium for restoring the capacity of the lithium-ion battery.

[0099] Furthermore, when the target charging voltage of the last positive electrode material in the active lithium release sequence is set, since there is no positive electrode material capable of releasing active lithium thereafter, when the active lithium released by it is consumed to a certain amount, the service life of the lithium-ion battery will end. Therefore, in order to let the user know the battery life status, a prompt can be issued so that the user can take corresponding measures according to the prompt, for example, replace the lithium-ion battery with a new one after the set date.

[0100] 102. Monitor the battery health status value of the lithium-ion battery.

[0101] The battery health status value is the ability of the lithium-ion battery in its current state to store electrical energy relative to its initial state. It expresses the state of the lithium-ion battery from the beginning to the end of its life in the form of a percentage, and is used to quantitatively describe the performance state of the current lithium-ion battery. The definition parameters of the battery health status value are determined by any of the following parameters: battery capacity, battery power, battery internal resistance, and remaining number of cycles. In actual applications, the definition parameters of the battery health status value can be selected from any of the above based on specific business needs.

[0102] Exemplarily, when the battery health status value is defined by battery capacity, it is necessary to obtain the battery current capacity and the battery rated capacity, and then determine the battery health status value according to the following formula: "Battery health status value = (battery current capacity / battery rated capacity) × 100%".

[0103] The following describes several monitoring situations involved in monitoring the battery health status value of lithium-ion batteries:

[0104] The first is to monitor the battery health status of the lithium-ion battery at a preset frequency in order to promptly detect the situation where the active lithium in the lithium-ion battery has been consumed to the point where the normal power supply of the lithium-ion battery is affected. The preset frequency can be determined based on business needs and is not specifically limited in this embodiment.

[0105] Second, when the user has a need to monitor the battery health status value, he or she may issue a monitoring instruction to detect the battery health status value, and when the monitoring instruction is received, the battery health status value of the lithium-ion battery is monitored.

[0106] This situation is applicable to scenarios where the user actively initiates battery health status value monitoring when the user finds that the power supply of the lithium-ion battery is insufficient and suspects that the active lithium of the lithium-ion battery has been consumed too much.

[0107] The third type is that since each positive electrode material in the lithium-ion battery releases active lithium at its corresponding target charging voltage, when the lithium-ion battery is detected to be in a charging state, the battery health status value of the lithium-ion battery is monitored. Because, in the charging state of the lithium-ion battery, once the battery health status value is detected to be abnormal, the charging voltage of the lithium-ion battery can be set in time to the target charging voltage corresponding to the positive electrode material currently to release active lithium, so that the positive electrode material currently to release active lithium releases active lithium for restoring the battery capacity.

[0108] 103. When the battery health state value of the lithium-ion battery is not greater than the battery health state threshold, the charging voltage of the lithium-ion battery is set to a target charging voltage corresponding to the positive electrode material currently to release active lithium.

[0109] When the battery health status value of the lithium-ion battery is not greater than the battery health status threshold value, it indicates that the active lithium in the lithium-ion battery has been consumed, and the capacity of the lithium-ion battery has reached a second preset battery capacity that cannot supply power normally. At this time, in order to extend the service life of the lithium-ion battery, it is necessary to set the charging voltage of the lithium-ion battery to a target charging voltage corresponding to the positive electrode material of the active lithium to be released at present, so that when the lithium-ion battery is charged at the target charging voltage, the positive electrode material of the active lithium to be released at present is stimulated to release the active lithium, thereby restoring the battery capacity of the lithium-ion battery.

[0110] It should be noted that the use of lithium-ion batteries is a continuous process. When the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, the lithium-ion battery may be in a charging state or a discharging state. When the lithium-ion battery is in a charging state, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the active lithium to be released at present, and the charging continues directly at the target charging voltage, and the positive electrode material of the active lithium to be released at present releases the active lithium. When the lithium-ion battery is in a discharging state, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the active lithium to be released at present, and when the lithium-ion battery is charged again, it is charged at the target charging voltage, and the positive electrode material of the active lithium to be released at present releases the active lithium.

[0111] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. When the lithium-ion battery is put into use, the battery health status value of the lithium-ion battery is monitored. Once the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the current active lithium to be released, so that the positive electrode material of the current active lithium to be released releases active lithium at the target charging voltage to replenish the capacity of the lithium-ion battery. It can be seen that by setting the target charging voltage, the positive electrode plate of the lithium-ion battery releases active lithium in steps. The active lithium of the positive electrode plate of this lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equal to the total amount of all positive electrode materials used, and the amount used can match the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided by the present application can extend the service life of lithium-ion batteries while reducing the amount of negative electrode materials used in lithium-ion batteries.

[0112] Further, according to Figure 1 Another embodiment of the present application further provides a method for controlling the charging voltage of a lithium-ion battery. The method is used to control the charging voltage of the lithium-ion battery. The lithium-ion battery involved here has a positive electrode sheet comprising at least two positive electrode materials, each of which has its own corresponding target charging voltage, and each of which releases active lithium at its corresponding target charging voltage. Figure 2 As shown, the charging voltage control method of the lithium-ion battery mainly includes the following steps:

[0113] 201. Determine a target charging voltage corresponding to each positive electrode material in a lithium-ion battery.

[0114] In order to realize the step-by-step release of active lithium in lithium-ion batteries, it is necessary to determine the active lithium release order of various positive electrode materials. The process of determining the active lithium release order is described below: first, the charging platform voltage of each positive electrode material is obtained, and then the active lithium release order of each positive electrode material is set according to the charging platform voltage of each positive electrode material, wherein, for any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the later order is greater than the charging platform voltage of the positive electrode material in the earlier order.

[0115] Each positive electrode material has its own corresponding target charging voltage, and each positive electrode material releases active lithium at its corresponding target charging voltage. The target charging voltage of each positive electrode material is related to its charging platform voltage. The following is an explanation of the method for determining the target charging voltage of various materials, which includes the following two methods:

[0116] The first method is to set the target charging voltage corresponding to the later positive electrode material to any voltage between the charging platform voltages of the two adjacent positive electrode materials for any two adjacent positive electrode materials in the active lithium release sequence.

[0117] For any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the later positive electrode material is any voltage between the charging platform voltages of the two adjacent positive electrode materials. The purpose of setting the target charging voltage corresponding to the later positive electrode material to any voltage between the charging platform voltages of the two adjacent positive electrode materials is that when the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the later positive electrode material, the later positive electrode material can be stimulated to release active lithium to restore the battery capacity of the lithium-ion battery, and the positive electrode material in the front sequence can be ensured not to undergo a serious phase change.

[0118] The target charging voltage corresponding to the positive electrode material that ranks first in the active lithium release order is determined based on the charging platform voltage it has. The target charging voltage is not greater than the corresponding charging platform voltage to avoid serious phase change of the positive electrode material.

[0119] The second method is to obtain the target points corresponding to the charging platform voltages of the two adjacent positive electrode materials in the relationship curve between the charging voltage and the state of charge of the lithium-ion battery for any two adjacent positive electrode materials in the active lithium release sequence; and determine the target charging voltage corresponding to the positive electrode material in the latter sequence as the voltage corresponding to the point with the maximum slope in the curve between the two target points.

[0120] First, determine the relationship curve between the charging voltage and the state of charge of the lithium-ion battery where the positive electrode plate of the lithium-ion battery is located. The relationship curve is a curve in the coordinate system where the horizontal axis is the state of charge and the vertical axis is the charging voltage. The relationship curve reflects the situation that the state of charge changes with the charging voltage. The points corresponding to the charging platform voltages of the two adjacent positive electrode materials in the relationship curve are the target points, and the voltage range corresponding to the curve between the two target points in the relationship curve is the selection range of the target charging voltage corresponding to the positive electrode material in the later order. In this voltage range, the charging voltage corresponding to the relatively small slope, the state of charge changes greatly when the charging voltage increases slightly, that is, the state of charge changes quickly in the place with a small slope, and the impact of the voltage error is very large at this time. The charging voltage corresponding to the place with a large slope, the charging voltage increases slightly, and the state of charge changes relatively small, that is, the state of charge changes relatively slowly in the place with a large slope. Therefore, the state of charge error caused by the voltage error is relatively small. Therefore, the target charging voltage corresponding to the positive electrode material in the later order is the voltage corresponding to the point with the largest slope in the curve between the two target points.

[0121] For example, Figure 3 As shown, the lithium-ion battery positive electrode plate of the lithium-ion battery includes the following two positive electrode materials: a first material and a second material, and the charging platform voltage of the second material is greater than the charging platform voltage of the first material. The capacity ratio of the first material and the second material is 5:1. The relationship curve between the charging voltage (Vollage) and the state of charge (SOC) of the lithium-ion battery is curve A. The points corresponding to the charging platform voltages of the first material and the second material in the relationship curve are Ua and Ub, respectively. The voltage range corresponding to the curve between the two points Ua and Ub in the relationship curve is the selection range of the target charging voltage corresponding to the second material. The voltage corresponding to the point Uc with the maximum slope in the curve between Ua and Ub is selected as the target charging voltage of the second material.

[0122] 202. Determine the positive electrode material of the lithium-ion battery that is currently to release active lithium.

[0123] 203. Select a battery health status threshold corresponding to the positive electrode material currently to release active lithium.

[0124] Various positive electrode materials may correspond to the same battery health state threshold or different battery health state thresholds. The battery health state threshold is a factor in determining whether to set the target charging voltage. Therefore, it is necessary to select a battery health state threshold corresponding to the positive electrode material currently to be released active lithium.

[0125] The battery health state threshold is any value within the second value range. The value in the second value range is used to limit that when the capacity of the lithium-ion battery reaches the second preset battery capacity that cannot supply power normally, the active lithium released by the positive electrode material to release active lithium at least restores the capacity of the lithium-ion battery to the third preset battery capacity, and the released active lithium does not cause lithium deposition in the lithium-ion battery.

[0126] The second numerical range is related to whether the lithium-ion battery can work normally, so the second numerical range needs to be set according to the following principles:

[0127] First, for the lower limit of the second numerical interval: the battery health status value corresponding to the lithium-ion battery capacity reaching the lower limit value at which it cannot supply power normally is set as the lower limit value of the second numerical interval. At this battery health status value, the battery capacity will not work normally. Therefore, in order to ensure that the lithium-ion battery can still work normally before the positive electrode material replenishes the active lithium, the lower limit value of the second numerical interval is set to the battery health status value corresponding to the lithium-ion battery capacity reaching the lower limit value at which it cannot supply power normally.

[0128] Second, for the upper limit of the second numerical interval: the upper limit of the second numerical interval is set based on the lithium replenishment ratio of the positive electrode material to be released active lithium. The lithium replenishment ratio P of the positive electrode material refers to the ratio of the newly added capacity of the battery to the initial capacity of the battery after the target charging voltage corresponding to the positive electrode material is set, which is determined when the lithium-ion battery leaves the factory.

[0129] The following is an example of a method for determining the lithium replenishment ratio P, in which a lithium-ion battery positive electrode sheet includes the following two positive electrode materials: a first material and a second material, and the charging platform voltage of the second material is greater than the charging platform voltage of the first material. The method includes the following two methods:

[0130] One method is to first obtain the initial capacity of the lithium-ion battery, set the capacity before and after the target charging voltage, and then obtain it through the following formula: P = (Q2-Q1) / Q, where Q2-Q1 represents the battery capacity increase, and Q represents the initial capacity of the battery.

[0131] Another method is to determine the lithium supplement ratio P by the following formula:

[0132]

[0133] Wherein, ε is the proportion of the second material in the mixed material composed of the first material and the second material, η a is the percentage of gram capacity of the first material before the target charging voltage of the second material is turned on, η bis the percentage of gram capacity of the second material before the target charging voltage of the second material is turned on, k is the gram capacity ratio of the second material to the second material, and ICE is the first coulombic efficiency of the lithium-ion battery.

[0134] After determining the lithium replenishment ratio of the positive electrode material to be released active lithium, the value of 1-P / m is determined, and the obtained value is set as the upper limit of the second numerical range. Wherein, m is a constant, and its value can be determined according to specific requirements. For example, the value of m is 1.5.

[0135] Exemplarily, the second numerical range is 50%≤X≤1-P / m, where X is the battery health state threshold.

[0136] 204. Monitor the battery health status value of the lithium-ion battery.

[0137] 205. When the battery health state value of the lithium-ion battery is not greater than the battery health state threshold, the charging voltage of the lithium-ion battery is set to a target charging voltage corresponding to the positive electrode material currently to release active lithium.

[0138] It should be noted that when the battery health state value of the lithium-ion battery is greater than the battery health state threshold value, it means that the active lithium in the lithium-ion battery can still support the normal operation of the lithium-ion battery, and then 204 can be continued.

[0139] 206. The capacity of the lithium-ion battery is monitored.

[0140] After the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material currently to release active lithium, if the lithium-ion battery is charged, the positive electrode material currently to release active lithium releases active lithium at the target charging voltage. After the active lithium is released, the capacity of the lithium-ion battery will be restored.

[0141] Although the target charging voltage can stimulate the positive electrode material currently to release active lithium to release active lithium, it may not be the most suitable charging voltage for charging the lithium-ion battery. Therefore, after setting the charging voltage of the lithium-ion battery to the target charging voltage corresponding to the positive electrode material currently to release active lithium, it is necessary to monitor the capacity of the lithium-ion battery so as to set a charging voltage suitable for charging the lithium-ion battery when the capacity of the lithium-ion battery is restored.

[0142] 207. When it is monitored that the capacity of the lithium-ion battery is a fourth preset battery capacity, the charging voltage of the lithium-ion battery is set to any value within the charging voltage range.

[0143] Before the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material to be currently released active lithium, the charging voltage of the lithium-ion battery is any value in the target charging voltage range, the lower limit of the target charging voltage range is greater than or equal to the value of the lower limit charging voltage of the positive electrode material to be first released lithium ions in the active lithium release sequence. The upper limit of the target charging voltage range is a value less than the target charging voltage of the positive electrode material to be currently released active lithium.

[0144] After the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material to be currently released active lithium, and after the positive electrode material to be currently released active lithium releases active lithium at the target charging voltage, the charging voltage of the lithium-ion battery is set to any value within the charging voltage range, wherein the lower limit of the charging voltage range is greater than or equal to the value of the charging lower limit voltage of the positive electrode material that first releases lithium ions in the active lithium release sequence, and the upper limit is not greater than the charging upper limit voltage of the positive electrode material to be currently released active lithium, and is less than the value of the target charging voltage corresponding to the positive electrode material immediately following the positive electrode material to be currently released active lithium. It can be seen that after the positive electrode material to be currently released active lithium releases active lithium at the target charging voltage, the charging voltage range of the lithium-ion battery is expanded, which is more conducive to the selection of power supplies with multiple voltages for charging it.

[0145] Furthermore, the following examples 1-8 and the lithium-ion batteries of comparative examples 1-2 are used to illustrate that the positive electrode plate of the lithium-ion battery and the charging voltage control method of the lithium-ion battery provided in the embodiments of the present application can extend the service life of the lithium-ion battery while reducing the use of the negative electrode material of the lithium-ion battery.

[0146] In Example 1, lithium iron phosphate is used as the positive electrode sheet material, and the mixed slurry is stirred in a conventional positive electrode slurry stirring manner to obtain a mixed slurry, and then the slurry is coated on the surface of the aluminum foil, dried, cold pressed, and cut to form a positive electrode sheet A; similarly, artificial graphite is used as the negative electrode material, and after stirring, it is evenly coated on the copper foil current collector, and then dried, cold pressed, and cut to form a negative electrode sheet B. The design N / P value of the negative electrode sheet B and the positive electrode sheet A is 1.05. The lithium-ion battery is assembled by stacking, and the operating voltage range of the battery is 2.5 to 3.65V. The electrochemical test is carried out at a temperature of 25°C.

[0147] In Example 2, NCM523 is used as the positive electrode sheet material, and the positive electrode slurry is stirred in a conventional stirring manner to obtain a mixed slurry, and then the slurry is coated on the surface of the aluminum foil, and then dried, cold pressed, and cut to form a positive electrode sheet A; similarly, artificial graphite is used as the negative electrode material, and after stirring, it is evenly coated on the copper foil current collector, and then dried, cold pressed, and cut to form a negative electrode sheet B. The design N / P value of the negative electrode sheet B and the positive electrode sheet A is 1.05. The lithium-ion battery is assembled by stacking, and the operating voltage range of the battery is 2.5-4.3V. The electrochemical test is carried out at a temperature of 25°C.

[0148] Example 1 and Example 2 were tested and the following results were obtained: Figure 4 The relationship curve between state of charge and charging voltage is shown in the figure. In the relationship curve, Volume is the charging voltage and SOC is the state of charge. From the test results, it can be seen that the charging platform voltage of lithium iron phosphate (LFP) is about 3.3V, and the charging platform voltage of NCM523 is about 3.68V. There is a difference between the charging platform voltages of the two, and the difference is not less than 0.1V. Therefore, lithium iron phosphate and NCM523 can be used as positive electrode materials for positive electrode sheets. The target charging voltage of NCM523 is between 3.3V and 3.68V.

[0149] After determining the two positive electrode materials included in the lithium-ion battery, the following Examples 3-8 are set:

[0150] In Example 3, lithium iron phosphate is used as the first material, NCM523 is used as the second material, the first material and the second material are mixed in a capacity ratio of 3:1, and stirred in a conventional positive electrode slurry stirring manner to obtain a mixed slurry, and then the slurry is coated on the surface of the aluminum foil, and then dried, cold pressed, and cut to form a positive electrode plate A. Similarly, artificial graphite is used as the negative electrode material, and after stirring, it is evenly coated on the copper foil current collector, and then dried, cold pressed, and cut to form a negative electrode plate B. The N / P value of the negative electrode plate B and the positive electrode plate A is 0.7875. Lithium-ion batteries are assembled in a stacking manner. The relationship curve between the charging voltage and the state of charge of the lithium-ion battery where the positive electrode plate of the lithium-ion battery is located is determined. In the voltage range of 2.5 to 4.3V, the voltage at the maximum point of the slope of the curve between the charging platform voltage of the first material and the second material is 3.47V, so the target charging voltage V corresponding to the second material is determined. 换 =3.47V, before setting the target charging voltage, the capacity of the first material is utilized to account for ηa=99.37%, and the capacity of the second material is utilized to account for η b =7.80%, the lithium replenishment ratio P is 40.1%. In order to ensure that the second material releases active lithium without causing lithium precipitation, the battery health status threshold SOH ≤ 60.2%. Set the battery management system parameters in the battery management system BMS: target charging voltage V 换=3.47V, the battery health threshold is 60%. Then the lithium-ion battery is electrochemically tested at 25°C.

[0151] Example 4

[0152] The difference between Example 4 and Example 3 is that the first material and the second material are added in a capacity ratio of 4:1, the designed N / P value is 0.84, and the target charging voltage V corresponding to the second material is 换 =3.52V, before setting the target charging voltage, the capacity of the first material is utilized to account for ηa=99.64%, and the capacity of the second material is utilized to account for η b =12.75%, the lithium replenishment ratio P is 28.1%, in order to ensure that the second material releases active lithium without causing lithium precipitation, the battery health state threshold SOH≤72.2%, and the battery management system parameters are set in the battery management system BMS: the battery health state threshold is 60%, and other variables are consistent with Example 3.

[0153] Example 5

[0154] The difference between Example 5 and Example 4 is that the battery management system parameters are set in the battery management system BMS: the battery health status threshold is 65%, and other variables remain consistent with Example 4.

[0155] Example 6

[0156] The difference between Example 6 and Example 5 is that the battery management system parameters are set in the battery management system BMS: the battery health status threshold is 70%, and other variables are consistent with Example 5.

[0157] Example 7

[0158] The difference between Example 7 and Example 3 is that the capacity ratio of the first material to the second material is 5:1, the designed N / P value is 0.875, and the target charging voltage V corresponding to the second material is 换 =3.54V, before setting the target charging voltage, the capacity of the first material is utilized to a certain extent η a =99.79%, the second material capacity utilization ratio η b 16.55%, the lithium replenishment ratio P is 21.4%, in order to ensure that the second material releases active lithium without causing lithium precipitation, the battery health state threshold SOH ≤ 79.0%, and the battery management system parameters are set in the battery management system BMS: the battery health state threshold is 70%, and other variables are consistent with Example 3.

[0159] Example 8

[0160] The difference between Example 8 and Example 3 is that the capacity ratio of the first material to the second material is 10:1, the designed N / P value is 0.94, and the target charging voltage V corresponding to the second material is 换 =3.59V, before setting the target charging voltage, the capacity of the first material is utilized to a certain extent η a =99.88%, the second material capacity utilization ratio η b =21.31%, the lithium replenishment ratio P is 10.2%, in order to ensure that the second material releases active lithium without causing lithium precipitation, the battery health state threshold SOH≤90.1%, and the battery management system parameters are set in the battery management system BMS: the battery health state threshold is 70%, and other variables are consistent with Example 3.

[0161] Comparative Example 1

[0162] The difference between the comparative example 1 and the embodiment 3 is that the positive electrode material is only lithium iron phosphate, the capacity is about 120Ah, the N / P value is 1.05, the battery assembly test is consistent with the above, and the BMS does not adopt the charging voltage control strategy of the lithium-ion battery to perform lithium replenishment control.

[0163] Comparative Example 2

[0164] The difference between the comparative example 2 and the comparative example 1 is that the positive electrode material is only NCM523, the capacity is about 120Ah, the N / P value is 1.05, the battery assembly test is consistent with the above, and the BMS does not adopt the charging voltage control strategy of the lithium-ion battery for lithium replenishment control.

[0165] The battery equipment parameters of the lithium-ion batteries involved in the above-mentioned Examples 3 to 8 and Comparative Examples 1 and 2 are shown in Table 1.

[0166] Table-1

[0167]

[0168] The lithium-ion batteries involved in the above-mentioned Examples 3 to 8 and Comparative Examples 1 to 2 were subjected to battery cycle tests under the same test conditions, and the test results shown in Table 2 were obtained.

[0169] Table-2

[0170]

[0171] It can be seen from the test results of Examples 3, 4, 7, and 8 that as the proportion of the second material in the first material and the second material increases, the SOH threshold value X becomes smaller and smaller, because the amount of active lithium released by the second material increases as its proportion in the first material and the second material increases. If the proportion of the second material increases and X is set too large, then when the second material releases active lithium, the risk of lithium deposition in the lithium-ion battery will increase.

[0172] The test results of Examples 5-8 can prove that when the mixing ratio of the first material and the second material in the examples is the same, the smaller the SOH threshold value X, the higher the capacity retention rate of the lithium-ion battery when the battery is cycled 7000 times. This is because the smaller the X value, the more lithium supplement material will be retained. After setting the target charging voltage of the second material, the capacity of the lithium-ion battery will be increased more after the second material releases active lithium.

[0173] The smaller the proportion of the second material in the first material and the second material, the less active lithium the second material can provide after setting the target charging voltage of the second material, so the capacity improvement effect is not obvious. Figure 5 As shown, curve 1 is a 4:1 capacity ratio of the first material to the second material, curve 2 is a 5:1 capacity ratio of the first material to the second material, and curve 3 is a 10:1 capacity ratio of the first material to the second material. It can be seen that the smaller the proportion of the second material, the less active lithium can be provided by the second material after setting the target charging voltage for the second material, so the effect of improving the capacity is not obvious.

[0174] It can be clearly seen from the results of Examples 3-8 and Comparative Examples 1-2 that by setting the charging voltage of the lithium-ion battery to the target charging voltage of the second material through the BMS, the second material releases active lithium at the target charging voltage, and after lithium replenishment of the lithium-ion battery, the battery cycle retention rate is improved, which greatly slows down the capacity decay and extends the battery life. Figure 6 In the figure, the curve corresponding to LFP is the relationship curve between the SOH value and the number of cycles of the lithium-ion battery whose positive electrode sheet only includes LFP as a positive electrode material. From the curve, it can be seen that the SOH value decreases with the number of cycles of lithium ions, and when the cycle reaches 7000 times, the SOH value decreases to 60%. Figure 6In the figure, the curve corresponding to LFP+NCM53 is the relationship curve between the SOH value and the number of cycles of the lithium-ion battery whose positive electrode sheet includes two positive electrode materials, LFP and NCM53. The relationship curve consists of two sections. The first section, curve 1, is a curve in which the SOH value decreases to 70% as the number of cycles of the lithium-ion battery reaches 3800. The second section, curve 2, is when the SOH value decreases to 70%, the BMS sets the charging voltage of the lithium-ion battery to the target charging voltage corresponding to the second material, and the second material releases active lithium at the target charging voltage. After the second material releases active lithium, the capacity of the lithium-ion battery is restored, so that the SOH value of the lithium-ion battery rises back to 92%. The lithium-ion battery then continues to cycle, and when it cycles to 7000 times, the SOH value decreases to 75%. It can be seen that compared with the lithium-ion battery whose positive electrode plate only includes LFP, under the same number of cycles, the lithium-ion battery whose positive electrode plate includes both LFP and NCM53 positive electrode materials has a much greater SOH value than the former because its positive electrode plate releases active lithium to supplement the capacity of the lithium battery. It can be seen that the positive electrode plate including two positive electrode materials can extend the service life of the lithium-ion battery.

[0175] It is not difficult to see from the above embodiments and comparative examples that after adopting the lithium-ion battery positive electrode plate and the charging voltage control strategy of the lithium-ion battery, the N / P value of the lithium-ion battery is significantly reduced, and can be less than 1, thereby reducing the amount of negative electrode material used. Therefore, the solution provided in the embodiment of the present application can extend the service life of the lithium-ion battery while reducing the amount of negative electrode material used in the lithium-ion battery, thereby achieving the purpose of reducing production costs.

[0176] Further, according to the above method embodiment, another embodiment of the present application also provides a battery management system, which is used to control the charging voltage of a lithium-ion battery, wherein the positive electrode plate of the lithium-ion battery involved includes at least two positive electrode materials, each of which has its own corresponding target charging voltage, and each of which releases active lithium at its corresponding target charging voltage, such as Figure 7 As shown, the battery management system includes:

[0177] A determination unit 31 is used to determine the positive electrode material currently to release active lithium in the lithium-ion battery;

[0178] A monitoring unit 32, used to monitor the battery health status value of the lithium-ion battery;

[0179] The setting unit 33 is configured to set the charging voltage of the lithium-ion battery to a target charging voltage corresponding to the positive electrode material currently to release active lithium when the battery health state value of the lithium-ion battery is not greater than a battery health state threshold.

[0180] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. When the lithium-ion battery is put into use, the battery health status value of the lithium-ion battery is monitored. Once the battery health status value of the lithium-ion battery is not greater than the battery health status threshold, the charging voltage of the lithium-ion battery is set to the target charging voltage corresponding to the positive electrode material of the current active lithium to be released, so that the positive electrode material of the current active lithium to be released releases active lithium at the target charging voltage to replenish the capacity of the lithium-ion battery. It can be seen that by setting the target charging voltage, the positive electrode plate of the lithium-ion battery releases active lithium in steps. The active lithium of the positive electrode plate of this lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equal to the total amount of all positive electrode materials used, and the amount used can match the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided by the present application can extend the service life of lithium-ion batteries while reducing the amount of negative electrode materials used in lithium-ion batteries.

[0181] In some embodiments, Figure 8 As shown, the battery management system also includes:

[0182] An acquisition unit 34 is used to acquire the charging platform voltage of each positive electrode material;

[0183] The setting unit 35 is used to set the active lithium release order of each of the positive electrode materials according to the charging platform voltage of each of the positive electrode materials, wherein, for any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the latter order is greater than the charging platform voltage of the positive electrode material in the former order.

[0184] In some embodiments, Figure 8 As shown, the determination unit 31 is specifically configured to, when the target charging voltage of any of the positive electrode materials is set, determine the positive electrode material immediately following it as the positive electrode material currently to release active lithium.

[0185] In some embodiments, Figure 8 As shown, the battery management system also includes:

[0186] The first setting unit 36 ​​is used for setting the target charging voltage corresponding to the subsequent positive electrode material to any voltage between the charging platform voltages of the two adjacent positive electrode materials in the active lithium release sequence.

[0187] In some embodiments, Figure 8 As shown, the battery management system also includes:

[0188] The second setting unit 37 is used for obtaining, for any two adjacent positive electrode materials in the active lithium release sequence: the target points corresponding to the charging platform voltages of the two adjacent positive electrode materials in the relationship curve between the charging voltage and the state of charge of the lithium-ion battery; and determining the target charging voltage corresponding to the positive electrode material in the latter sequence as the voltage corresponding to the point with the maximum slope in the curve between the two target points.

[0189] In some embodiments, Figure 8 As shown, the battery management system also includes:

[0190] A selection unit 38 is used to select a battery health status threshold value corresponding to the positive electrode material of the current active lithium to be released, wherein the battery health status threshold value is any value within a second numerical range, wherein the value in the second numerical range is used to limit that when the capacity of the lithium-ion battery reaches a second preset battery capacity that cannot supply power normally, the active lithium released by the positive electrode material of the current active lithium to be released at least restores the capacity of the lithium-ion battery to a third preset battery capacity, and the released active lithium will not cause lithium deposition in the lithium-ion battery.

[0191] In some embodiments, Figure 8 As shown, the battery management system also includes:

[0192] The third setting unit 39 is used to set the battery health status value corresponding to the lower limit value of the lithium-ion battery capacity reaching the normal power supply as the lower limit value of the second numerical range; and set the upper limit value of the second numerical range based on the lithium replenishment ratio of the positive electrode material to be released active lithium.

[0193] In some embodiments, Figure 8 As shown, the battery management system also includes:

[0194] The fourth setting unit 40 is used to set the charging voltage of the lithium-ion battery to any value within the charging voltage range when it is monitored that the capacity of the lithium-ion battery is a fourth preset battery capacity, wherein the lower limit value of the charging voltage range is greater than or equal to the value of the charging lower limit voltage of the first positive electrode material that releases lithium ions in the active lithium release sequence, and the upper limit value is not greater than the charging upper limit voltage of the positive electrode material that is currently to release active lithium, and is less than the value of the target charging voltage corresponding to the positive electrode material that is sequentially adjacent to the positive electrode material that is currently to release active lithium.

[0195] In some embodiments, Figure 8As shown, the monitoring unit 32 is specifically used to monitor the battery health status value of the lithium-ion battery at a preset frequency; or, when a monitoring instruction for monitoring the battery health status value is received, monitor the battery health status value of the lithium-ion battery; or, when it is detected that the lithium-ion battery is in a charging state, monitor the battery health status value of the lithium-ion battery.

[0196] In the battery management system provided in the embodiment of the present application, the detailed description of the methods used in the operation of each functional module can be found in Figure 1-Figure 2 The corresponding method of the method embodiment is explained in detail and will not be repeated here.

[0197] Furthermore, according to the above embodiment, another embodiment of the present application also provides a lithium-ion battery, and the lithium-ion battery includes: the above lithium-ion battery positive electrode plate.

[0198] In the technical solution of the embodiment of the present application, the positive electrode plate of the lithium-ion battery includes two or more positive electrode materials, and each positive electrode material has its own corresponding target charging voltage. Each positive electrode material releases active lithium at its corresponding target charging voltage. The lithium-ion battery with such a positive electrode plate of the lithium-ion battery has the ability to release active lithium in steps. The active lithium of the positive electrode plate of such a lithium-ion battery is not released all at once, but when the active lithium currently possessed by the lithium-ion battery decays to affect the normal use of the battery, the positive electrode plate is controlled to release active lithium in steps by adjusting the charging voltage. The amount of negative electrode material used does not need to be equivalent to the total amount of all positive electrode materials used, and the amount used can be matched with the active lithium released by the positive electrode plate in each step, thereby reducing the amount of negative electrode material used. Therefore, the solution provided in the present application can extend the service life of the lithium-ion battery while reducing the amount of negative electrode material used in the lithium-ion battery.

[0199] In some embodiments, the lithium-ion battery further comprises: Figure 7 and 8 The battery management system mentioned in.

[0200] In some embodiments, the ratio of the negative electrode capacity to the positive electrode capacity of the lithium-ion battery is any value in a third numerical range, the lower limit of the third numerical range is a value not less than 0.67, and the upper limit is a value not greater than 1.

[0201] The ratio between the negative electrode capacity and the positive electrode capacity is the N / P value of the lithium-ion battery. From the third numerical range of its value, it can be seen that the amount of negative electrode material used is not greater than the amount of positive electrode material used. The amount of negative electrode material used can match the active lithium released by the positive electrode sheet in each step, so it can extend the service life of the lithium-ion battery while reducing the amount of negative electrode material used in the lithium-ion battery.

[0202] Further, according to the above embodiments, another embodiment of the present application also provides an electrical device, wherein the electrical device comprises a lithium-ion battery as described in any one of the above, and the lithium-ion battery is used to provide electrical energy.

[0203] In some embodiments, the electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like.

[0204] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0205] It is understandable that the related features in the above methods and devices can be referenced to each other. In addition, the "first", "second" and the like in the above embodiments are used to distinguish the embodiments, but do not represent the advantages and disadvantages of the embodiments.

[0206] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0207] The algorithm and display provided herein are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the application is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the application described herein, and the description of the specific language above is for the purpose of disclosing the best mode of implementation of the application.

[0208] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0209] Similarly, it should be understood that in order to streamline the present disclosure and assist in understanding one or more of the various aspects of the application, in the above description of exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof.

[0210] Those skilled in the art will appreciate that the modules in the devices in the embodiments can be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and in addition they can be divided into multiple submodules or subunits or subassemblies. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification (including the accompanying abstract and drawings) and all processes or units of any method or device disclosed in this manner can be combined in any combination. Unless otherwise explicitly stated, each feature disclosed in this specification (including the accompanying abstract and drawings) can be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0211] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features from different embodiments is meant to be within the scope of the present application and to form different embodiments.

[0212] The various component embodiments of the present application may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) may be used in practice to implement some or all of the functions of some or all of the components in the operating method, device, and framework of the deep neural network model according to the embodiment of the present application. The present application may also be implemented as a device or device program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present application may be stored on a computer-readable medium, or may be in the form of one or more signals. Such a signal may be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0213] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A positive electrode plate for a lithium-ion battery, characterized in that: The lithium-ion battery positive electrode plate includes: at least two positive electrode materials, wherein each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage.

2. The positive electrode sheet of a lithium-ion battery according to claim 1, characterized in that: Each of the positive electrode materials has its own corresponding charging platform voltage, and the charging platform voltage of each of the positive electrode materials defines the active lithium release order of each of the positive electrode materials. For any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the later order is greater than the charging platform voltage of the positive electrode material in the earlier order.

3. The positive electrode plate of a lithium-ion battery according to claim 2, characterized in that: For any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the positive electrode material in the latter sequence is any voltage between the charging platform voltages of the two adjacent positive electrode materials.

4. The positive electrode plate of a lithium-ion battery according to claim 2, characterized in that: For any two adjacent positive electrode materials in the active lithium release sequence, the target charging voltage corresponding to the positive electrode material in the later sequence is the voltage corresponding to the point with the largest slope in the curve between the two target points, wherein the two target points are respectively the points corresponding to their respective charging platform voltages in the curve of the relationship between the charging voltage and the state of charge of the lithium ion battery where the positive electrode plate of the lithium ion battery is located.

5. The positive electrode sheet of a lithium-ion battery according to any one of claims 1 to 4, characterized in that: The positive electrode plate of the lithium-ion battery comprises the following two positive electrode materials: a first material and a second material, wherein the charging platform voltage of the second material is greater than the charging platform voltage of the first material; The proportion of the second material in the first material and the second material is any value within a first numerical range, wherein the values ​​in the first numerical range are used to limit the active lithium released by the second material at its corresponding target charging voltage to at least restore the capacity of the lithium-ion battery to a first preset battery capacity, and the released active lithium will not cause lithium deposition in the lithium-ion battery.

6. The positive electrode plate of a lithium-ion battery according to claim 5, characterized in that: The lower limit of the first numerical range is a value not less than 3%, and the upper limit is a value not greater than 50%.

7. The positive electrode plate of a lithium-ion battery according to claim 5, characterized in that: The first material and the second material are independently selected from any one of the following materials: LiFePO4, LiCoO2, LiNiO2, LiMn2O4, LiNi 0.5 Mn 1.5 O4, nickel-cobalt-manganese ternary materials.

8. A method for controlling charging voltage of a lithium-ion battery, characterized in that: The positive electrode sheet of the lithium-ion battery includes at least two positive electrode materials, each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage. The method includes: Determining the positive electrode material currently to release active lithium in the lithium-ion battery; Monitoring the battery health status value of the lithium-ion battery; When the battery health state value of the lithium ion battery is not greater than the battery health state threshold, the charging voltage of the lithium ion battery is set to a target charging voltage corresponding to the positive electrode material currently to release active lithium.

9. The method according to claim 8, characterized in that The method further comprises: Obtaining a charging platform voltage of each of the positive electrode materials; The active lithium release order of each of the positive electrode materials is set according to the charging platform voltage of each of the positive electrode materials, wherein, for any two adjacent positive electrode materials in the active lithium release order, the charging platform voltage of the positive electrode material in the later order is greater than the charging platform voltage of the positive electrode material in the earlier order.

10. The method according to claim 9, characterized in that Determining the positive electrode material currently to release active lithium in the lithium-ion battery, comprising: When the target charging voltage of any of the positive electrode materials is set, the positive electrode material immediately following it is determined as the positive electrode material currently to release active lithium.

11. The method according to claim 9, characterized in that The method further comprises: For any two adjacent positive electrode materials in the active lithium release sequence: setting the target charging voltage corresponding to the positive electrode material in the latter sequence to any voltage between the charging platform voltages of the two adjacent positive electrode materials; or, For any two adjacent positive electrode materials in the active lithium release sequence: obtain the target points corresponding to the charging platform voltages of the two adjacent positive electrode materials in the relationship curve between the charging voltage and the state of charge of the lithium-ion battery; determine the target charging voltage corresponding to the positive electrode material in the later sequence as the voltage corresponding to the point with the maximum slope in the curve between the two target points.

12. The method according to any one of claims 8 to 11, characterized in that: The method further comprises: A battery health status threshold value corresponding to the positive electrode material currently to release active lithium is selected, wherein the battery health status threshold value is any value within a second numerical range, wherein the values ​​in the second numerical range are used to limit that when the capacity of the lithium-ion battery reaches a second preset battery capacity that cannot supply power normally, the active lithium released by the positive electrode material currently to release active lithium at least restores the capacity of the lithium-ion battery to a third preset battery capacity, and the released active lithium does not cause lithium deposition in the lithium-ion battery.

13. The method according to claim 12, characterized in that The method further comprises: Setting the battery health status value corresponding to the lithium-ion battery capacity reaching the lower limit value at which the battery cannot supply power normally as the lower limit value of the second value interval; The upper limit of the second numerical range is set based on the lithium replenishment ratio of the positive electrode material to be released active lithium.

14. The method according to any one of claims 8 to 11, characterized in that: After setting the charging voltage of the lithium-ion battery to a target charging voltage corresponding to the positive electrode material currently to release active lithium, the method further includes: When it is monitored that the capacity of the lithium-ion battery is a fourth preset battery capacity, the charging voltage of the lithium-ion battery is set to any value within the charging voltage range, wherein the lower limit value of the charging voltage range is greater than or equal to the value of the charging lower limit voltage of the first positive electrode material that releases lithium ions in the active lithium release sequence, and the upper limit value is not greater than the charging upper limit voltage of the positive electrode material that is currently to release active lithium, and is less than the value of the target charging voltage corresponding to the positive electrode material that is sequentially adjacent to the positive electrode material that is currently to release active lithium.

15. The method according to any one of claims 8 to 11, characterized in that: Monitors battery health status values ​​of lithium-ion batteries, including: Monitoring the battery health status value of the lithium-ion battery at a preset frequency; or, When receiving a monitoring instruction for monitoring a battery health status value, monitoring the battery health status value of the lithium-ion battery; or, When it is detected that the lithium-ion battery is in a charging state, a battery health status value of the lithium-ion battery is monitored.

16. A battery management system, characterized in that: The positive electrode sheet of the lithium-ion battery includes at least two positive electrode materials, each of the positive electrode materials has its own corresponding target charging voltage, and each of the positive electrode materials releases active lithium at its corresponding target charging voltage. The battery management system includes: A determination unit, used to determine the positive electrode material currently to release active lithium in the lithium-ion battery; A monitoring unit, used to monitor the battery health status value of the lithium-ion battery; A setting unit is used for setting the charging voltage of the lithium ion battery to a target charging voltage corresponding to the positive electrode material currently to release active lithium when the battery health state value of the lithium ion battery is not greater than a battery health state threshold.

17. A lithium ion battery, characterized in that: The lithium-ion battery comprises: a lithium-ion battery positive electrode sheet as described in any one of claims 1 to 7.

18. The lithium ion battery according to claim 17, characterized in that: The lithium-ion battery further comprises: a battery management system as claimed in claim 16.

19. The lithium ion battery according to claim 17 or 18, characterized in that: The ratio of the negative electrode capacity to the positive electrode capacity of the lithium ion battery is any value in a third numerical range, the lower limit of the third numerical range is a value not less than 0.67, and the upper limit is a value not greater than 1.

20. An electrical device, characterized in that: The electrical device comprises a lithium-ion battery as described in any one of claims 17 to 19, and the lithium-ion battery is used to provide electrical energy.

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