WO2024031236A1 - 二次电池、电池及用电装置 - Google Patents

二次电池、电池及用电装置 Download PDF

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Publication number
WO2024031236A1
WO2024031236A1 PCT/CN2022/110842 CN2022110842W WO2024031236A1 WO 2024031236 A1 WO2024031236 A1 WO 2024031236A1 CN 2022110842 W CN2022110842 W CN 2022110842W WO 2024031236 A1 WO2024031236 A1 WO 2024031236A1
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Prior art keywords
negative electrode
lithium
electrode sheet
layer
secondary battery
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PCT/CN2022/110842
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English (en)
French (fr)
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严青伟
王家政
董晓斌
许贺可
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/110842 priority Critical patent/WO2024031236A1/zh
Publication of WO2024031236A1 publication Critical patent/WO2024031236A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers

Definitions

  • the present application relates to the field of battery technology, and in particular to a secondary battery, a battery and an electrical device.
  • lithium-ion batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their first Coulombic efficiency, cycle performance and storage performance.
  • the present application provides a secondary battery, a battery and a power device, which can improve the first Coulomb efficiency, cycle performance and storage performance of the secondary battery, battery and power device.
  • the application provides a secondary battery, including an electrode assembly.
  • the electrode assembly includes: at least one positive electrode piece and at least one negative electrode piece.
  • the negative electrode film layer of the at least one negative electrode piece has a non-reactive region, and the non-reactive region and The positive electrode film layers on the positive electrode sheet arranged adjacent to the negative electrode sheet are not arranged oppositely, and at least one non-reactive area is provided with a lithium supplement layer;
  • the total capacity of the secondary battery is Q
  • the total lithium-replenishing capacity of all lithium-replenishing layers is Q Li
  • Q Li satisfies the conditions: 0.5% Q ⁇ Q Li ⁇ 10% Q.
  • a lithium source is placed on the surface of the negative electrode film layer in the non-reaction zone and a lithium replenishing layer is formed.
  • the lithium on the lithium replenishing layer and the negative electrode film layer overlapping the lithium replenishing layer are formed of materials such as There is a potential difference of about 3V between graphite or silicon-carbon materials, and the voltage of lithium is lower than the voltage of the material forming the negative electrode film layer without lithium embedded therein.
  • the lithium replenishing layer and the non-reactive area of the negative electrode film layer carrying it are in a state of close contact, an electrical circuit is formed between the lithium replenishing layer and the negative electrode film layer carrying it, which is equivalent to In the state of direct short circuit (in this state, the lithium supplement layer is the negative electrode, and the negative electrode film layer carrying the lithium supplement layer is the positive electrode), under the action of their potential difference, the lithium in the lithium supplement layer will lose electrons and become free to move.
  • Lithium ions are embedded in the negative electrode film layer that supports them, and form LiCx (x ⁇ 6) with C (carbon) in the negative electrode film layer, or/and, and form LixSiy with Si (silicon) in the negative electrode film layer that supports them. (x>0,y>0).
  • the original lithium supplement layer, LiCx and/or LixSiy are combined to form a new stable lithium supplement layer.
  • the new stable lithium replenishment layer has a lower potential. Since lithium ions are embedded from the lower potential area to the higher potential area, during the charging process, the new stable lithium replenishment layer can effectively prevent the same negative electrode from charging.
  • the lithium ions in the reaction area on the chip diffuse and embed into the non-reaction area, and during the discharge process, the potential of the reaction area of the negative electrode gradually increases. At this time, the potential of the reaction area is much higher than the potential of the non-reaction area.
  • the new The lithium ions in the stable lithium supplement layer will diffuse toward the reaction zone at a slow rate driven by this potential difference, thereby improving the first Coulombic efficiency, cycle performance and storage performance of the secondary battery.
  • the lithium supplement layer is a lithium metal elemental layer.
  • the lithium alloy in the lithium replenishing layer made of lithium alloys such as silicon-lithium alloy, aluminum-lithium alloy, magnesium-lithium alloy, and tin-lithium alloy has a relatively low gram capacity. After lithium removal, metal impurities will be formed, which may deteriorate the safety performance of the secondary battery. risks of.
  • the lithium metal element in the lithium metal element layer has a high theoretical gram capacity and less residue after the reaction. It can not only improve the first efficiency, cycle and storage performance of the secondary battery, but also does not reduce the energy density of the secondary battery.
  • Q Li satisfies the condition: 2% Q ⁇ Q Li ⁇ 6% Q.
  • the lithium supplement amount of the lithium supplement layer in the range of: 2% Q ⁇ Q Li ⁇ 6% Q.
  • 2% Q ⁇ Q Li ⁇ 6% Q it can not only improve the first Coulombic efficiency, cycle performance and storage performance of the secondary battery, but also have a higher utilization rate of the lithium supplement layer.
  • the electrode assembly includes a separation film, and the electrode assembly is configured as a laminate structure formed by a stack of positive electrode sheets, separation films, and negative electrode sheets;
  • the surface of the outermost negative electrode film layer in the outermost negative electrode sheet forms a non-reactive area, and the lithium supplement layer covers the non-reactive area.
  • the lithium replenishing area of the lithium replenishing layer can be effectively increased, thereby making the electrode assembly of the laminate structure have a larger High first coulombic efficiency, cycle performance and storage performance.
  • the electrode assembly includes a separation film, and the electrode assembly is configured as a rolled structure formed by rolling a positive electrode sheet, a separation film, and a negative electrode sheet;
  • the electrode assembly includes a starting winding section and a finishing winding section, all positive electrode sheets and all negative electrode sheets 1232 in the starting winding section, the surface of the innermost negative electrode film layer in the innermost negative electrode sheet, and/or Among all positive electrode sheets and all negative electrode sheets in the ending winding section, a non-reactive area is formed on the surface of the outermost negative electrode film layer in the outermost negative electrode sheet, and at least one of the starting winding section and the ending winding section The non-reactive area on the top is equipped with a lithium supplement layer.
  • non-reactive areas may be provided in both the initial winding section and the final winding section of the electrode assembly. The more sites in the non-reaction zone, the more conducive to the distribution of the lithium replenishment layer, so that the location of the lithium replenishment layer can be selected as needed.
  • each non-reactive zone in the initial winding section and the final winding section is provided with a lithium replenishing layer
  • the total lithium replenishing capacity of all lithium replenishing layers provided on the initial winding section is Q 1
  • the total lithium replenishing capacity of all lithium replenishing layers on the finishing winding section is Q 2
  • Q Li Q 1 + Q 2
  • Q 1 > Q 2 is the total lithium replenishing capacity of all lithium replenishing layers provided on the initial winding section
  • the initial winding section is located in the center of the electrode assembly compared to the final winding section, when the initial winding section is fully infiltrated by the electrolyte, the liquid retention capacity is much higher than that of the final winding section. In this way, it is more conducive to the diffusion of lithium ions in the lithium supplement layer to further improve the first Coulomb efficiency, cycle and storage performance of the battery cell.
  • the total lithium supplement area of all lithium supplement layers is S Li
  • the capacity per unit area of the negative electrode film layer on one side of each negative electrode piece 1232 is C negative
  • S Li satisfies the condition: Q Li /120% C Negative ⁇ S Li ⁇ Q Li /20% C negative .
  • the potential of the non-reactive area on the negative electrode sheet is directly related to the lithium supplement area of the non-reactive area.
  • the larger the lithium replenishing area the greater the potential reduction in the non-reactive area of the negative electrode sheet.
  • the potential of the entire negative electrode sheet will also be reduced.
  • the potential difference between the negative electrode piece and the positive electrode piece adjacent to the negative electrode piece will be larger.
  • S Li satisfies the condition: Q Li /90% C negative ⁇ S Li ⁇ Q Li /50% C negative .
  • the lithium replenishment area in the secondary battery is more appropriate and the utilization rate is higher, which can effectively improve the first Coulombic efficiency, cycle performance and storage performance of the secondary battery.
  • the lithium replenishment layer includes:
  • a plurality of first lithium replenishing units are arranged at intervals along the longitudinal direction of the negative electrode sheet; and/or
  • a plurality of second lithium replenishing units are arranged at horizontal intervals along the negative electrode sheet.
  • the lithium replenishment layer can be quickly embedded into the overlapping negative electrode film layer and form a new stable lithium replenishment layer.
  • the new stable lithium replenishment layer can slowly Replenishes lithium ions, thereby helping to extend the life of secondary batteries.
  • each first lithium replenishing unit extends along the lateral direction of the negative electrode sheet to two opposite edges of the negative electrode sheet.
  • the space of the non-reaction zone can be fully utilized to set up the first lithium replenishment unit, so that the first lithium replenishment unit has a larger length. Subsequently, the lithium replenishment capacity of the first lithium replenishment unit also increases, so that Secondary batteries have good lithium replenishment effect. In addition, the gap formed between each adjacent two first lithium replenishing units can also ensure that the electrolyte can be fully infiltrated.
  • each second lithium replenishment unit includes a plurality of lithium replenishment parts, each lithium replenishment part is block-shaped, and all lithium replenishment parts of each second lithium replenishment unit are along the longitudinal length of the negative electrode sheet.
  • Direction interval setting is a plurality of lithium replenishment parts, each lithium replenishment part is block-shaped, and all lithium replenishment parts of each second lithium replenishment unit are along the longitudinal length of the negative electrode sheet.
  • the lithium replenishing layer is configured as a layer structure extending continuously along the longitudinal direction of the negative electrode sheet where it is located.
  • the lithium supplement layer is provided with multiple through holes.
  • the porosity of the negative electrode sheet can be increased so that the electrolyte can be fully infiltrated, thereby helping to extend the service life of the secondary battery.
  • the lithium supplement area of the lithium supplement layer is S 1
  • the sum of the cross-sectional areas of all the through holes on the lithium supplement layer is S 2
  • S 2 satisfies the condition: 5% S 1 ⁇ S 2 ⁇ 50% S1 .
  • S 2 By setting S 2 to meet the conditions: 5% S 1 ⁇ S 2 ⁇ 50% S 1 , it can not only meet the demand for lithium replenishment, but also enable the electrolyte to fully infiltrate, thus helping to further improve the first Coulomb rate of the secondary battery. Efficiency, cycle performance and storage performance.
  • S 2 satisfies the condition: 20% S 1 ⁇ S 2 ⁇ 30% S 1 .
  • the electrolyte has better wetting and lithium replenishing effects.
  • the present application provides a battery, which includes the secondary battery as described in any of the above embodiments.
  • the present application provides an electrical device, which includes a battery as described in the above embodiments, and the battery is used to provide electric energy; or includes a secondary battery as described in any of the above embodiments, where the secondary battery Batteries are used to provide electrical energy.
  • Figure 1 is a schematic structural diagram of a vehicle in some embodiments of the present application.
  • Figure 2 is an exploded view of a battery in some embodiments of the present application.
  • Figure 3 is an exploded view of a secondary battery in some embodiments of the present application.
  • Figure 4 is a cross-sectional view of the electrode assembly in a wound structure in some embodiments of the present application.
  • FIG 5 is an expanded schematic view of the negative electrode sheet of the electrode assembly in the embodiment shown in Figure 4;
  • Figure 6 is an expanded schematic view of the negative electrode sheet of the electrode assembly in another embodiment shown in Figure 4;
  • FIG 7 is an expanded schematic diagram of the negative electrode sheet of the electrode assembly shown in Figure 4.
  • FIG. 8 is an expanded schematic view of the negative electrode sheet of the electrode assembly shown in FIG. 4 in yet another embodiment.
  • first and second are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as “first” and “second” may explicitly or implicitly include at least one of these features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.
  • connection In this application, unless otherwise clearly stated and limited, the terms “installation”, “connection”, “connection”, “fixing” and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated into one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interactive relationship between two elements, unless otherwise specified restrictions. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
  • a first feature being “on” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. touch.
  • the terms “above”, “above” and “above” the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature.
  • "Below”, “below” and “beneath” the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.
  • Batteries are not only used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace. As battery application fields continue to expand, its market demand is also expanding.
  • the lithium ions of the positive electrode sheet are preferentially embedded in the reaction area of the negative electrode sheet 1232, causing the potential of the reaction area to decrease and forming a potential difference with the non-reactive area of the negative electrode sheet 1232.
  • Lithium ions diffuse and embed in the non-reactive area at a slow speed, and the lithium ions embedded in the non-reactive area have difficulty returning to the positive electrode sheet during the discharge process. This causes irreversible lithium loss of the positive electrode sheet and worsens the first Coulombic efficiency of the battery cell. , cycle performance and storage performance. Therefore, existing lithium-ion batteries still need to be improved in terms of first Coulombic efficiency, cycle performance, and storage performance.
  • the electrode assembly includes: at least one The positive electrode sheet and at least one negative electrode sheet 1232 have a non-reactive area on the negative electrode film layer of the at least one negative electrode sheet 1232.
  • the non-reactive area and the positive electrode film layer on the positive electrode sheet adjacent to the negative electrode sheet 1232 are not opposite to each other, and at least A lithium replenishing layer is provided on a non-reactive zone; among them, the total capacity of the secondary battery is Q, the total lithium replenishing capacity of all lithium replenishing layers is Q Li , and Q Li satisfies the conditions: 0.5% Q ⁇ Q Li ⁇ 10% Q .
  • a reaction region is also provided.
  • the reaction area is arranged opposite to the positive electrode film layer on the positive electrode sheet 1232 adjacent to the negative electrode sheet 1232 where it is located.
  • the lithium source before liquid injection, the lithium source is placed on the non-reactive zone and forms a lithium replenishing layer.
  • the lithium on the lithium replenishing layer and the forming material of the negative electrode film layer overlapping the lithium replenishing layer such as graphite or silicon carbon material.
  • the lithium replenishing layer and the non-reactive area of the overlapping negative electrode film layer are in close contact, an electrical circuit is formed between the lithium replenishing layer and the overlapping negative electrode film layer, which is equivalent to In the state of direct short circuit (in this state, the lithium supplement layer is the negative electrode, and the negative electrode film layer overlapping the lithium supplement layer is the positive electrode), under the action of the potential difference, the lithium in the lithium supplement layer will lose electrons and become freely mobile.
  • Lithium ions are embedded in the negative electrode film layer overlapping the lithium supplement layer, and form LiCx (x ⁇ 6) with C (carbon) in the negative electrode film layer, or/and, and Si in the negative electrode film layer overlapping the lithium supplement layer (Silicon) forms LixSiy(x>0,y>0).
  • the original lithium supplement layer, LiCx and/or LixSiy are combined to form a new stable lithium supplement layer.
  • the new stable lithium replenishment layer makes the potential of the non-reaction area lower. Since lithium ions are embedded from the lower potential area to the higher potential area, during the charging process, the new stable lithium replenishment layer can It effectively prevents the lithium ions in the reaction area on the same negative electrode sheet 1232 from diffusing and embedding into the non-reactive area, and during the discharge process, the potential of the reaction area of the negative electrode sheet 1232 gradually increases. At this time, the potential of the reaction area is much higher than The potential of the non-reactive zone, the lithium ions in the new stable lithium supplement layer will diffuse to the reaction zone at a slow rate driven by the potential difference, thereby improving the first Coulombic efficiency, cycle performance and storage performance of the secondary battery.
  • Q Li meets the conditions: 0.5% Q ⁇ Q Li ⁇ 10% Q.
  • the total lithium replenishing capacity of the lithium replenishing layer is within this range. It also has a good lithium replenishing effect and can further improve the first Coulombic efficiency of the secondary battery. , cycle performance and storage performance.
  • the secondary battery 12 disclosed in the embodiment of the present application can be used in, but is not limited to, vehicles 1 , ships, aircraft and other electrical devices.
  • the power supply system of the electrical device can be composed of the secondary battery 12, battery 10, etc. disclosed in the present application.
  • a lithium replenishing layer is provided for the non-reactive region 12321 of the negative electrode sheet 1232, which is beneficial to improving the first Coulombic efficiency of the battery 10. Loop performance and storage performance.
  • Embodiments of the present application provide an electrical device that uses a battery 10 as a power source.
  • the electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc.
  • electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc.
  • spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.
  • an electrical device in an embodiment of the present application is a vehicle 1 as an example.
  • Vehicle 1 can be a fuel vehicle, a gas vehicle, or a new energy vehicle.
  • the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or a range-extended vehicle.
  • the battery 10 is disposed inside the vehicle 1 , and the battery 10 can be disposed at the bottom, head, or tail of the vehicle 1 .
  • the battery 10 may be used to power the vehicle 1 , for example, the battery 10 may serve as an operating power source for the vehicle 1 .
  • the vehicle 1 may also include a controller 20 and a motor 30 .
  • the controller 20 is used to control the battery 10 to provide power to the motor 30 , for example, to meet the power requirements for starting, navigation and driving of the vehicle 1 .
  • the battery 10 can not only be used as an operating power source of the vehicle 1 , but also can be used as a driving power source of the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .
  • the battery 10 includes a case 11 and a secondary battery 12 .
  • the secondary battery 12 is accommodated in the case 11 .
  • the box 11 is used to provide a storage space for the secondary battery 12, and the box 11 can adopt a variety of structures.
  • the box body 11 may include a first part 111 and a second part 112 , the first part 111 and the second part 112 cover each other, and the first part 111 and the second part 112 jointly define a space for accommodating the secondary battery 12 of accommodation space.
  • the second part 112 may be a hollow structure with one end open, and the first part 111 may be a plate-like structure.
  • the first part 111 covers the open side of the second part 112 so that the first part 111 and the second part 112 jointly define a receiving space.
  • the first part 111 and the second part 112 may also be hollow structures with one side open, and the open side of the first part 111 is covered with the open side of the second part 112.
  • the box 11 formed by the first part 111 and the second part 112 can be in various shapes, such as a cylinder, a cuboid, etc.
  • the battery 10 there may be a plurality of secondary batteries 12 , and the plurality of secondary batteries 12 may be connected in series, in parallel, or in a mixed connection.
  • a mixed connection means that the plurality of secondary batteries 12 are connected in series and in parallel.
  • the plurality of secondary batteries 12 can be directly connected in series or in parallel or mixed together, and then the plurality of secondary batteries 12 can be housed in the box 11 as a whole; of course, the battery 10 can also be a plurality of secondary batteries 12
  • the battery modules are first connected in series, parallel, or mixed to form a battery module, and then multiple battery modules are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 11 .
  • the battery 10 may also include other structures.
  • the battery 10 may further include a bus component for realizing electrical connection between multiple secondary batteries 12 .
  • the secondary battery 12 refers to the smallest unit that constitutes the battery 10 . As shown in FIG. 3 , the secondary battery 12 includes an end cap 122 , a case 121 , an electrode assembly 123 and other functional components.
  • the end cap 122 refers to a component that covers the opening of the case 121 to isolate the internal environment of the secondary battery 12 from the external environment.
  • the shape of the end cap 122 may be adapted to the shape of the housing 121 to fit the housing 121 .
  • the end cap 122 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 122 is less likely to deform when subjected to extrusion and impact, allowing the secondary battery 12 to have a higher structure. Strength and safety performance can also be improved.
  • the end cap 122 may be provided with functional components such as electrode terminals. The electrode terminals may be used to electrically connect with the electrode assembly 123 for outputting or inputting electric energy of the secondary battery 12 .
  • the end cap 122 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the secondary battery 12 reaches a threshold.
  • the end cap 122 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.
  • an insulating member may also be provided inside the end cover 122, and the insulating member may be used to isolate the electrical connection components in the housing 121 from the end cover 122 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber, etc.
  • the case 121 is a component used to cooperate with the end cover 122 to form an internal environment of the secondary battery 12 , wherein the formed internal environment can be used to accommodate the electrode assembly 123 , electrolyte, and other components.
  • the housing 121 and the end cover 122 may be independent components, and an opening may be provided on the housing 121, and the end cover 122 covers the opening at the opening to form an internal environment of the secondary battery 12.
  • the end cap 122 and the shell 121 can also be integrated. Specifically, the end cap 122 and the shell 121 can form a common connection surface before other components are put into the shell. When it is necessary to encapsulate the inside of the shell 121 When the end cap 122 is closed, the housing 121 is closed.
  • the housing 121 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 121 can be determined according to the specific shape and size of the electrode assembly 123 .
  • the housing 121 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.
  • the electrode assembly 123 is a component in the secondary battery 12 where electrochemical reactions occur.
  • One or more electrode assemblies 123 may be contained within the housing 121 .
  • the electrode assembly 123 is mainly formed by winding or stacking a positive electrode sheet 1231 and a negative electrode sheet 1232, and an isolation film 1233 is usually provided between the positive electrode sheet 1231 and the negative electrode sheet 1232.
  • the secondary battery 12 includes an electrode assembly 123.
  • the electrode assembly 123 includes: at least one positive electrode sheet 1231 and at least one negative electrode sheet 1232.
  • the at least one negative electrode sheet 1232 has a non-reactive region 12321 on the negative electrode film layer,
  • the non-reactive area 12321 and the positive electrode film layer on the positive electrode sheet 1231 adjacent to the negative electrode sheet 1232 are not arranged oppositely, and at least one non-reactive area 12321 is provided with a lithium replenishing layer 1234; wherein, the total of the secondary battery 12
  • the capacity is Q
  • the total lithium-replenishing capacity of all lithium-replenishing layers 1234 is Q Li .
  • Q Li satisfies the conditions: 0.5% Q ⁇ Q Li ⁇ 10% Q.
  • the electrode assembly 123 also includes an isolation film 1233.
  • the positive electrode sheet 1231, the isolation film 1233 and the negative electrode sheet 1232 are stacked in sequence.
  • the positive electrode sheets 1231 and the negative electrode sheets 1232 may be arranged alternately or non-alternatively.
  • the alternate arrangement refers to the stacking method of positive electrode sheet 1231, isolation film 1233, negative electrode sheet 1232, isolation film 1233, positive electrode sheet 1231, isolation film 1233, negative electrode sheet 1232..., or the stacking method of negative electrode sheet 1232, isolation film 1233, positive electrode sheet 1231, isolation film 1233, negative electrode sheet 1232, isolation film 1233, positive electrode sheet 1231... stacking method.
  • Non-alternating arrangement means that the same kind of pole pieces are stacked adjacently.
  • the non-alternating mode can be the setting of positive electrode sheet 1231, positive electrode sheet 1231, isolation film 1233, negative electrode sheet 1232, isolation film 1233, positive electrode sheet 1231, positive electrode sheet 1231, isolation film 1233, negative electrode sheet 1232... Way.
  • An isolation film 1233 may be optionally provided between two adjacent negative electrode sheets 1232 and between two adjacent positive electrode sheets 1232, or no isolation film 1233 may be provided.
  • a polyethylene film with a thickness of 12 ⁇ m is selected as the isolation film 1233 .
  • the positive electrode sheet 1231 includes a positive electrode current collector and positive electrode film layers arranged on opposite sides of the positive electrode current collector along the thickness direction of the positive electrode current collector.
  • the specific preparation process of the positive electrode sheet is as follows: Mix lithium iron phosphate, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) in a mass ratio of 96:2:2, and add solvent N-methylpyrrolidone (NMP) , stir under the action of a vacuum mixer until the system is uniform, and obtain the positive electrode slurry.
  • PVDF polyvinylidene fluoride
  • NMP solvent N-methylpyrrolidone
  • the cathode slurry was evenly coated on both surfaces of the cathode current collector with a thickness of 12 ⁇ m, dried at 115°C for 15 minutes under high temperature conditions, and cold pressed to obtain a cathode film layer with a thickness of 84 ⁇ m, and then cut into long lengths.
  • the positive electrode sheet 1231 with a film width of 605mm and a film width of 88mm has a coating weight of 20mg/cm2 and a compacted density of 2.4g/ cm3 .
  • the negative electrode sheet 1232 includes a negative electrode current collector and negative electrode film layers disposed on opposite sides of the negative electrode current collector along the thickness direction of the negative electrode current collector.
  • the specific preparation process of negative electrode sheet 1232 is as follows: mix artificial graphite, conductive agent acetylene black, thickener sodium carboxymethyl cellulose (CMC), and binder SBR in a mass ratio of 96.4:1:1.2:1.4, and add solvent Deionized water, stir until the system is uniform under the action of a vacuum mixer to obtain a negative electrode slurry; apply the negative electrode slurry evenly on both surfaces of the negative electrode current collector with a thickness of 8 ⁇ m, dry at 115°C for 15 minutes, and cold press A negative electrode film layer with a thickness of 61 ⁇ m on one side was obtained, and was cut to obtain a negative electrode sheet 1232 with a length of 735 mm and a film width of 93 mm.
  • the coating weight of the negative electrode sheet 1232 was 9.4 mg/cm 2 and the compact
  • Each negative electrode sheet 1232 has a positive electrode sheet 1231 arranged adjacent to it on one side or both opposite sides.
  • the negative electrode sheet 1232 and the positive electrode sheet 1231 are arranged adjacent to each other. This means that the negative electrode sheet 1232 and the positive electrode sheet 1231 are stacked on the same isolation film 1233. opposite sides of.
  • At least one negative electrode film layer of each negative electrode sheet 1232 has a reaction region 12322, and at least one negative electrode sheet 1232 has a non-reactive region 12321 on the negative electrode film layer. Only the reaction zone 12322 is provided on each negative electrode film layer on the negative electrode sheet 1232 with adjacent positive electrode sheets 1231 on opposite sides. Only one side of the negative electrode sheet 1232 with adjacent positive electrode sheets 1231 faces the positive electrode sheet.
  • a reaction region 12322 is provided on the negative electrode film layer of 1231.
  • a non-reactive region 12321 is provided on the negative electrode film layer and/or the negative electrode film layer located opposite to the negative electrode film layer. That is to say, in the negative electrode sheet 1232 with the adjacent positive electrode sheet 1231 on only one side, only the reaction region 12322 may be provided on the negative electrode film layer of the negative electrode sheet 1232 facing the adjacent positive electrode sheet 1231, or A reaction area 12322 and a non-reaction area 12321 may be provided at the same time. Only the non-reaction area 12321 can be provided on the negative electrode film layer of the negative electrode sheet 1232 facing away from the adjacent positive electrode sheet 1231.
  • the reaction region 12322 can be provided on each negative electrode film layer of the negative electrode sheet 1232. It can be seen that the non-reactive region 12321 is only located on the negative electrode piece 1232 with the positive electrode piece 1231 adjacent to it on one side.
  • the reaction area 12322 and the non-reaction area 12321 can be located on the same negative electrode film layer, or they can be located on different negative electrode film layers, and the reaction area 12322 and the non-reactive area 12321 are located on their respective negative electrode film layers. The surface facing away from the negative current collector.
  • the reaction area 12322 is opposite to the positive electrode film layer on the positive electrode sheet 1231 adjacent to the negative electrode sheet 1232, and the non-reaction area 12321 and the non-reaction area 12321 are opposite to each other.
  • the positive electrode film layers on the positive electrode sheet 1231 adjacent to the negative electrode sheet 1232 are not arranged opposite to each other.
  • the relative arrangement of the reaction area 12322 and the positive electrode film layer on the cathode sheet 1231 adjacent to the negative electrode sheet 1232 means that when the isolation film 1233 between the reaction area 12322 and the cathode film layer is ignored, the reaction The area 12322 and the positive electrode sheet 1231 are arranged facing each other, and the projections of the reaction area 12322 and the positive electrode film layer in the stacking direction of the positive electrode sheet 1231 and the negative electrode sheet 1232 completely overlap.
  • the fact that the non-reactive area 12321 and the positive electrode film layer on the positive electrode sheet 1231 adjacent to the negative electrode sheet 1232 are not arranged oppositely means that the non-reactive area 12321 and the positive electrode film layer of the positive electrode sheet 1231 are arranged facing each other, and the non-reactive area 12321
  • the projection of the positive electrode film in the stacking direction of the positive electrode sheet 1231 and the negative electrode sheet 1232 does not overlap at all, and/or the non-reactive region 12321 is arranged back to the positive electrode film layer of the positive electrode sheet 1231.
  • the non-reactive region 12321 and the positive electrode film layer Whether the projections in the stacking direction of the positive electrode sheet 1231 and the negative electrode sheet 1232 overlap is not specifically limited.
  • the reaction region 12322 and the non-reaction region 12321 are located in the negative electrode film layer of the negative electrode sheet 1232 facing the positive electrode film layer of the positive electrode sheet 1231, the non-reactive region 12321 and the positive electrode film layer are stacked on the positive electrode sheet 1231 and the negative electrode sheet 1232.
  • the projections in the directions do not overlap at all; when the reaction area 12322 and the non-reaction area 12321 are located in different negative electrode film layers in the negative electrode sheet 1232, the reaction area 12322 and the positive electrode sheet 1231 are arranged facing each other, and the reaction area 12322 and the positive electrode film layer are in The projections in the stacking direction of the positive electrode sheet 1231 and the negative electrode sheet 1232 completely overlap, and the non-reactive region 12321 is arranged back to the positive electrode film layer of the positive electrode sheet 1231.
  • the negative electrode of the outermost negative electrode sheet 1232 faces away from the positive electrode film layer on the adjacent positive electrode sheet 1231.
  • a non-reactive zone 12321 is formed on the surface of the film layer.
  • the electrode assembly 123 includes two positive electrode sheets 1231, two negative electrode sheets 1232, and three isolation films 1233.
  • the electrode assembly 123 consists of the positive electrode sheet 1231, the isolation film 1233, the negative electrode sheet 1232, the isolation film 1233, and the positive electrode.
  • the sheet 1231, the isolation film 1233, and the negative electrode sheet 1232 are arranged.
  • the first negative electrode sheet 1232 is located between the two positive electrode sheets 1231, so there is no non-reactive region 12321 in the first negative electrode sheet 1232.
  • the second negative electrode sheet 1232 is the outermost negative electrode sheet 1232, and the second negative electrode sheet 1232 faces away from the positive electrode of the adjacent second positive electrode sheet 1231.
  • a non-reactive region 12321 is formed on the surface of the negative electrode film layer.
  • the electrode assembly 123 includes a starting winding section, a finishing winding section, and an intermediate winding section connected between the starting winding section and the finishing winding section.
  • the negative electrode sheet 1232 located in the innermost layer includes arrows j, arrow O, arrow p, arrow K, arrow l, arrow
  • the outermost negative electrode sheet 1232 (as shown in Figure 4, the negative electrode sheet 1232 is formed by a combination of segments where arrows a, arrow b, arrow c, arrow d, arrow e, arrow f, arrow g, and arrow h are located)
  • Non-reactive areas 12321 can be formed on the surface of the outermost negative electrode film layer.
  • the surface of the innermost negative electrode film in the negative electrode sheet 1232 forms a non-reactive area 12321, and when there is the outermost layer in the final winding section
  • a non-reactive region 12321 is formed on the surface of the outermost negative electrode film layer of the negative electrode sheet 1232 .
  • Other negative electrode sheets 1232 located in the starting winding section, other negative electrode sheets 1232 located in the ending winding section, and all negative electrode sheets 1232 in the middle winding section have adjacent positive electrode sheets 1231 on each side. Only the reaction region 12322 can be formed on the surface of each negative electrode film layer of each negative electrode sheet 1232 in this section.
  • the innermost negative electrode sheet 1232 in the initial winding section refers to: among all the positive electrode sheets 1231 and all negative electrode sheets 1232 in the initial winding section, the layer of negative electrode sheets 1232 closest to the winding centerline;
  • the innermost negative electrode film layer among the innermost negative electrode sheets 1232 in the winding section refers to the negative electrode film layer closest to the winding center line of the innermost negative electrode sheet 1232 in the starting winding section.
  • the outermost negative electrode sheet 1232 in the ending winding section refers to the layer of negative electrode sheets 1232 farthest from the winding centerline among all the positive electrode sheets 1231 and all negative electrode sheets 1232 in the ending winding section.
  • the outermost negative electrode film layer among the outermost negative electrode sheets 1232 in the ending winding section refers to the negative electrode film layer of the outermost negative electrode sheet 1232 in the ending winding section that is farthest from the winding center line.
  • the electrode assembly 123 is defined as N turns, N>5 and N is a natural number.
  • the initial winding section (as shown in Figure 4 includes arrow j, arrow O, arrow p, arrow K, arrow l, arrow m, arrow r, the negative electrode sheet 1232 formed by the combination of the segments at the position of the arrow n (as a segment of the innermost negative electrode sheet 1232) consists of the first turn, or consists of the continuously arranged first turn and part of the second turn, or, also It can be composed of the 1st and 2nd turns, and the closing winding section (as shown in Figure 4 includes the positions of arrow a, arrow b, arrow c, arrow d, arrow e, arrow f, arrow g, and arrow h).
  • the negative electrode sheet 1232 formed by segment combination (as a segment of the outermost negative electrode sheet 1232) is composed of the last circle, or the last circle of the continuous arrangement and part of the second to last circle, or it can also be composed of the last circle and the second to last circle. composed of circles.
  • the middle coil is an assembly of all coil layers connected between the initial winding section and the final winding section.
  • the negative electrode sheet 1232 in at least one of the initial winding section and the final winding section has a non-reactive area 12321, and at least one non-reactive area 12321 of the initial winding section and the final winding section is provided with a lithium supplement layer 1234.
  • the non-reactive region 12321 may be the entire area or a partial area of the negative electrode film surface on the side of the negative electrode sheet 1232 that does not have the adjacent positive electrode sheet 1231. In an embodiment in which the electrode assembly 123 has a wound structure, the non-reactive region 12321 is a partial area of the negative electrode film surface on the side of the negative electrode sheet 1232 that does not have an adjacent positive electrode sheet 1231.
  • the lithium supplement layer 1234 refers to a substance that can supplement lithium ions inside the positive electrode sheet 1231.
  • the lithium supplement layer 1234 can be, but is not limited to, a substance that can provide active lithium, including but not limited to the following, such as lithium Foil, lithium powder, silicon-lithium alloy, aluminum-lithium alloy, magnesium-lithium alloy, tin-lithium alloy, etc.
  • the lithium replenishing layer 1234 can be formed by rolling, depositing or bonding.
  • the deposition method can be but is not limited to magnetron sputtering deposition.
  • the lithium source before liquid injection, the lithium source is placed on the surface of the negative electrode film layer in the non-reaction zone 12321 and forms the lithium supplement layer 1234, the lithium on the lithium supplement layer 1234, and the negative electrode film layer overlapping the lithium supplement layer.
  • the lithium supplement layer 1234 is the negative electrode, and the negative electrode film layer carrying the lithium supplement layer 1234 is the positive electrode.
  • the lithium in the lithium supplement layer 1234 will be lost.
  • the electrons become freely moving lithium ions and are embedded in the negative electrode film layer that supports them, and form LiCx (x ⁇ 6) with C (carbon) in the negative electrode film layer, or/and, and Si in the negative electrode film layer that supports them.
  • Silicon forms LixSiy(x>0,y>0).
  • the original lithium supplement layer, LiCx and/or LixSiy are combined to form a new stable lithium supplement layer.
  • the potential of the new stable lithium replenishment layer is lower, because lithium ions are embedded from the lower potential area to the higher potential area. In this way, during the charging process, the new stable lithium replenishment layer 1234 can effectively prevent the same.
  • the lithium ions in the reaction area 12322 on the negative electrode sheet 1232 diffuse and embed into the non-reactive area 12321, and during the discharge process, the potential of the reaction area 12322 of the negative electrode sheet 1232 gradually increases.
  • the potential of the reaction area 12322 is much higher than The potential of the non-reactive region 12321, the lithium ions in the new stable lithium supplement layer 1234 will diffuse to the reaction region 12322 at a slow speed driven by this potential difference, thereby improving the first Coulombic efficiency and cycle performance of the secondary battery 12 and storage performance.
  • the lithium supplement layer 1234 is a lithium metal elemental layer.
  • the lithium metal element can be lithium foil, lithium powder, etc.
  • the processing performance of lithium foil is better than that of lithium powder, so lithium foil is preferably used as the lithium supplement layer 1234 .
  • lithium supplement layer 1234 as lithium foil as an example
  • the production process of lithium foil is as follows:
  • Step 1 Design the total capacity Q of the secondary battery 12.
  • the unit of Q is ampere-hour (Ah).
  • Step 2 Calculate the total capacity Q Li that needs to be supplemented with lithium based on the total capacity of the secondary battery 12;
  • the third step test the secondary battery 12 using a button type to measure the capacity per unit area of the film layer on one side of each negative electrode piece 1232 as C minus , and the unit is ampere-hour/square centimeter (Ah/cm 2 ) ;
  • Step 7 Use a roller press to roll the lithium foil to the thickness calculated in step 6 to produce lithium foil that meets the theoretical design;
  • Step 8 Cut the lithium foil produced in step 7 to the required length and width according to the total lithium replenishing area S Li of the lithium foil, and place it in the non-reactive area 12321 of the negative electrode sheet 1232.
  • the lithium alloy in the lithium replenishing layer 1234 made of lithium alloys such as silicon-lithium alloy, aluminum-lithium alloy, magnesium-lithium alloy, and tin-lithium alloy has a relatively low gram capacity. Metal impurities will be formed after delithiation, which may deteriorate the secondary battery 12 Safety performance risks.
  • the lithium metal element in the lithium metal element layer has a high theoretical gram capacity and less residue after the reaction. It can not only improve the first efficiency, cycle and storage performance of the secondary battery 12, but also does not reduce the energy density of the secondary battery 12.
  • the lithium supplement amount of the lithium supplement layer 1234 in the range of: 2% Q ⁇ Q Li ⁇ 6% Q.
  • 2% Q ⁇ Q Li ⁇ 6% Q not only can the first Coulombic efficiency, cycle performance and storage performance of the secondary battery 12 be improved, but also a higher utilization rate of the lithium supplement layer 1234 can be achieved.
  • the electrode assembly 123 includes an isolation film 1233, and the electrode assembly 123 is configured as a laminate structure formed by a stack of positive electrode sheets 1231, isolation films 1233, and negative electrode sheets 1232; in all positive electrode sheets 1231 and all In the negative electrode sheet 1232, the surface of the outermost negative electrode film layer in the outermost negative electrode sheet 1232 forms a non-reactive area 12321, and the lithium supplement layer 1234 covers the non-reactive area 12321.
  • the lithium replenishment layer 1234 can completely cover the non-reaction area 12321, or can partially cover the non-reaction area 12321, and can be specifically set according to the lithium replenishment requirements.
  • the negative electrode film layer of the negative electrode sheet 1232 located in the middle layer does not have a non-reactive region 12321, and the outermost layer of the negative electrode sheet 1232 located in the outermost layer
  • the surface of the negative electrode film layer has a non-reactive area 12321.
  • the outermost negative electrode film layer among the outermost negative electrode sheets 1232 refers to the negative electrode film layer of the outermost negative electrode sheet 1232 facing away from the adjacent positive electrode sheet 1231 .
  • the outermost negative electrode sheet 1232 refers to the negative electrode sheet 1232 arranged at the first stacking position along the stacking direction and the negative electrode sheet 1232 at the last stacking position.
  • the stacking position refers to the position of each electrode piece in the electrode assembly 123.
  • the electrode assembly 123 includes a positive electrode piece 1231, a isolation film 1233 and a negative electrode piece 1232, and in the stacking direction, the positive electrode piece 1231, the isolation film
  • 1233 and the negative electrode sheet 1232 are arranged in sequence, the positive electrode sheet 1231 is in the first stacking position, and the negative electrode sheet 1232 is in the last stacking position.
  • the negative electrode sheet 1232 in the middle layer refers to the negative electrode sheet 1232 located in the stacking position between the first stacking position and the last stacking position.
  • the electrode assembly 123 of the laminate structure there is an outermost negative electrode sheet 1232 located at the first stacking position and/or the last stacking position.
  • the electrode assembly 123 is arranged along the stacking direction as follows: positive electrode sheet 1231 (located at the first stacking position), isolation film 1233, negative electrode sheet 1232 (located at the second stacking position), isolation film 1233, and positive electrode sheet 1231 (located at the third stacking position) , the isolation film 1233 and the negative electrode sheet 1232 (located at the last stacking position) are stacked as an example.
  • the negative electrode sheet 1232 at the second stacking position is the negative electrode sheet 1232 in the middle layer
  • the negative electrode sheet 1232 at the last stacking position is is the outermost negative electrode sheet 1232
  • the negative electrode sheet 1232 located at the last stacking position faces away from the negative electrode film layer located at the third stacking position, which is the outermost negative electrode film layer of the outermost layer negative electrode sheet 1232 .
  • the electrode assembly 123 is arranged along the stacking direction as follows: the isolation film 1233, the negative electrode sheet 1232 (located at the first stacking position), the isolation film 1233, the positive electrode sheet 1231 (located at the second stacking position), the isolation film 1233, and the negative electrode sheet 1232 (located at the second stacking position).
  • the last stacking position) and the isolation film 1233 are stacked as an example.
  • the negative electrode sheet 1232 located at the first stacking position and the last stacking position is the outermost negative electrode sheet 1232.
  • the negative electrode sheet 1232 in the first stacking position faces away from the negative electrode film layer of the positive electrode sheet 1231 in the second stacking position
  • the negative electrode sheet 1232 in the last stacking position faces away from the negative electrode film layer of the positive electrode sheet 1231 in the second stacking position. is the outermost negative electrode film layer in the outermost negative electrode sheet 1232 .
  • the lithium replenishing layer 1234 is provided on the outermost negative electrode film layer of the outermost negative electrode sheet 1232, and the lithium replenishing layer 1234 covers the non-reactive area 12321, which can effectively increase the lithium replenishing area of the lithium replenishing layer 1234, thus making the laminate structure
  • the electrode assembly 123 has higher first Coulombic efficiency, cycle performance and storage performance.
  • the electrode assembly 123 includes an isolation film 1233.
  • the electrode assembly 123 is configured as a rolled structure formed by winding the positive electrode sheet 1231, the isolation film 1233 and the negative electrode sheet 1232. ;
  • the electrode assembly 123 includes a starting winding section and a finishing winding section.
  • the outermost negative electrode sheet 1232 has a non-reactive area 12321 formed on the surface of the outermost negative electrode film layer, the starting winding section and The non-reactive region 12321 on at least one of the finishing winding sections is provided with a lithium replenishing layer 1234.
  • the innermost negative electrode film is located in the innermost negative electrode sheet 1232 of the initial winding section, and the outermost negative electrode film layer is located in the outermost negative electrode sheet 1232 of the ending winding section.
  • the surfaces of the negative electrode sheets 1232 all have non-reactive areas 12321, and the other negative electrode sheets 1232 only have reaction areas 12322.
  • the electrode assembly 123 includes a positive electrode sheet 1231, a separation film 1233 and a negative electrode sheet 1232, and the three are stacked sequentially along the stacking direction and then rolled to form the electrode assembly 123 with a wound structure.
  • the positive electrode sheet 1231 is closer to the negative electrode sheet 1232.
  • the positive electrode sheet 1231, the isolation film 1233 and the negative electrode sheet 1232, and the positive electrode sheet 1231 in each section is arranged close to the winding center line relative to the negative electrode sheet 1232.
  • only the outermost negative electrode sheet 1232 of the finishing winding section has a non-reactive area.
  • the electrode assembly 123 includes two negative electrode sheets 1232, two isolation films 1233 and one positive electrode sheet 1231, and is stacked along the stacking direction in the form of negative electrode sheets 1232, isolation films 1233, positive electrode sheets 1231, isolation films 1233, and negative electrode sheets 1232.
  • the electrode assembly 123 is formed by being stacked in different directions and then rolled to form a wound structure.
  • the negative electrode sheet 1232 is closer to the winding center line than the positive electrode sheet 1231 .
  • the first negative electrode sheet 1232 arranged along the stacking direction when unrolled is located in a section of the initial winding section. All positive electrode sheets 1231 forming the initial winding section and the innermost layer of all negative electrode sheets 1232 form the initial winding section.
  • the second negative electrode sheet 1232 arranged along the stacking direction is located in a section of the ending winding section, forming all the positive electrode sheets 1231 of the ending winding section and the outermost negative electrode sheet 1232 of all the negative electrode sheets 1232.
  • the electrode assembly 123 only includes a negative electrode sheet 1232, a positive electrode sheet 1231, and an isolation film 1233.
  • the electrode assembly 123 is formed in a stacked manner and then rolled to form a wound structure.
  • the negative electrode sheet 1232 is closer to the winding center line than the positive electrode sheet 1231, and the parts of the negative electrode sheet 1232 and the isolation film 1233 that extend beyond the positive electrode sheet 1231 are rolled to form an electrode assembly.
  • the closing winding section of 123 is a closing winding section of 123.
  • the initial winding section and the middle winding section of the electrode assembly 123 include the negative electrode sheet 1232, the isolation film 1233 and the positive electrode sheet 1231, but the final winding section only includes the negative electrode sheet 1232 and the isolation film. 1233.
  • the negative electrode sheet 1232 of the initial winding section (as shown in FIG. 4 includes arrows j, arrow O, arrow p, arrow K, arrow l, arrow m, arrow r, and arrow n).
  • the innermost negative electrode film layer of the negative electrode sheet 1232 formed by the combination of segments, and the negative electrode sheet 1232 of the final winding segment (including arrows a, arrow b, arrow c, arrow d, arrow e, arrow f in Figure 4
  • the outermost negative electrode film layer of the negative electrode sheet 1232 formed by the combination of the sections at the positions of arrows g and arrow h has a non-reactive area 12321.
  • the initial winding section when the negative electrode sheet 1232 is unrolled, the initial winding section
  • the non-reactive area 12321 and the non-reactive area 12321 of the ending winding section are distributed at the two opposite ends of the negative electrode sheet 1232 along the longitudinal direction X of the negative electrode sheet 1232, and are respectively located on the negative electrode film layers on the opposite sides of the negative electrode sheet 1232.
  • the non-reactive area 12321 in the initial winding section and the non-reactive area 12321 in the final winding section are both provided with lithium supplementary layers 1234.
  • the electrode assembly 123 has a wound structure and the electrode assembly 123 is arranged as shown in FIG. 4 as an example.
  • Lithium replenishing layers 1234 are provided in the non-reactive areas 12321 on the surface of the film.
  • the non-reactive area 12321 located on the innermost negative electrode sheet 1232 is provided with a lithium replenishing layer 1234, and/or at the end Among all the positive electrode sheets 1231 and all the negative electrode sheets 1232 in the winding section, the non-reactive area 12321 located on the outermost negative electrode sheet 1232 is provided with a lithium replenishing layer 1234. In this way, the first Coulombic efficiency and cycle of the electrode assembly 123 can be effectively improved. Performance and storage performance.
  • the non-reactive region 12321 may be provided in both the initial winding section and the final winding section of the electrode assembly 123 .
  • each non-reactive zone 12321 in the initial winding section and the final winding section is provided with a lithium supplement layer 1234, and all lithium supplement layers 1234 are provided on the initial winding section.
  • the total lithium replenishing capacity is Q 1
  • the total lithium replenishing capacity of all lithium replenishing layers 1234 provided on the finishing winding section is Q 2
  • Q Li Q 1 + Q 2
  • Q 1 > Q 2 is the total lithium replenishing capacity of all lithium replenishing layers 1234 provided on the finishing winding section.
  • the initial winding section is located at the center of the electrode assembly 123 compared to the final winding section, when the initial winding section is fully soaked by the electrolyte, the liquid retention capacity is much higher than that of the final winding section. In this way, it is more conducive to the diffusion of lithium ions in the lithium supplement layer 1234 to further improve the first Coulombic efficiency, cycle and storage performance of the battery cell.
  • the total lithium supplement area of all lithium supplement layers 1234 is S Li
  • the capacity per unit area of the negative electrode film layer on one side of each negative electrode piece 1232 is C negative
  • S Li satisfies the conditions: Q Li / 120% C negative ⁇ S Li ⁇ Q Li /20% C negative .
  • the potential of the non-reactive region 12321 on the negative electrode sheet 1232 is directly related to the lithium supplement area of the non-reactive region 12321.
  • the potential of the entire negative electrode sheet 1232 will also be reduced.
  • the potential difference between the negative electrode piece 1232 and the positive electrode piece 1231 adjacent to the negative electrode piece 1232 will be larger.
  • energy potential difference ⁇ capacity
  • S Li satisfies the condition: Q Li /90% C negative ⁇ S Li ⁇ Q Li /50% C negative .
  • the lithium replenishment area in the secondary battery 12 is more appropriate and the utilization rate is higher, which can effectively improve the first Coulombic efficiency, cycle performance and storage performance of the secondary battery 12 .
  • the lithium replenishment layer 1234 includes: a plurality of first lithium replenishment units 12341, which are spaced apart along the longitudinal direction X of the negative electrode sheet 1232; and/or A plurality of second lithium replenishment units 12342 are arranged at intervals along the lateral direction Y of the negative electrode sheet 1232 where they are located.
  • the longitudinal direction X of the negative electrode sheet 1232 is its length direction
  • the transverse direction Y of the negative electrode sheet 1232 is its width direction
  • the longitudinal direction The negative electrode sheet 1232 is wound along its longitudinal direction X.
  • the lithium replenishment layer 1234 may include only a plurality of first lithium replenishment units 12341, or may only include a plurality of second lithium replenishment units 12342, or may simultaneously include a plurality of first lithium replenishment units 12341 and multiple The second lithium replenishment unit 12342.
  • the first lithium replenishing unit 12341 and the second lithium replenishing unit 12342 may be arranged at an intersection or at intervals.
  • the lithium replenishment layer 1234 can be quickly embedded into the overlapping negative electrode film layer and form a new stable lithium replenishment layer 1234.
  • the new stable lithium replenishment layer 1234 can slowly replenish lithium ions, thereby helping to extend the service life of the secondary battery 12.
  • each first lithium replenishing unit 12341 extends along the transverse direction Y of the negative electrode sheet 1232 where it is located to two opposite edges of the negative electrode sheet 1232.
  • the first lithium replenishing unit 12341 may be in a strip shape, a rod shape, a rectangular shape, etc.
  • the space of the non-reaction area 12321 can be fully utilized to set up the first lithium replenishment unit 12341, so that the first lithium replenishment unit 12341 has a larger length. Subsequently, the lithium replenishment capacity of the first lithium replenishment unit 12341 also increases, so that the secondary battery 12 has a better lithium replenishing effect. In addition, the gap formed between each adjacent two first lithium replenishing units 12341 can also ensure that the electrolyte can be fully infiltrated.
  • each second lithium replenishment unit 12342 includes a plurality of lithium replenishment parts 123421, each lithium replenishment part 123421 is block-shaped, and all lithium replenishment parts 123421 of each second lithium replenishment unit 12342 are along the The negative electrode pieces 1232 are arranged at intervals in the longitudinal direction X.
  • the second lithium replenishing unit 12342 may be in the shape of a square, a circular block, a triangular block, etc., and the specific structure is not limited here.
  • the lithium replenishing layer 1234 is configured as a layer structure extending continuously along the longitudinal direction X of the negative electrode sheet 1232 where it is located.
  • the lithium supplement layer 1234 has a dense and continuous layer structure.
  • a plurality of through holes 12343 are opened on the lithium supplement layer 1234 .
  • the arrangement of the through holes 12343 can be a matrix arrangement or an irregular arrangement, and the specific form can be set according to requirements.
  • the manufacturing process of the lithium foil provided with multiple through holes 12343 is as follows:
  • the first step cut the produced lithium foil into the required length and width according to the total lithium supplement area S Li of the lithium foil;
  • Step 2 Use polyethylene film (PE film) to completely wrap the two front and back sides of the lithium foil along its thickness direction (to prevent the lithium foil from sticking to the hole making equipment during hole making)
  • PE film polyethylene film
  • Step 3 Pass the lithium foil wrapped with polyethylene film through the roller press at a uniform speed. Short and dense spikes are set on the surface of one of the rollers in the roller press. The appropriate roller gap is set as required. The lithium foil starts from After passing through the roller gap, porous lithium foil can be created.
  • the lithium replenishment layer 1234 has a dense and continuous layer structure, after the electrode assembly 123 is rolled and formed, the non-reaction area 12321 covered by the lithium replenishment layer 1234 will not be completely wetted by the electrolyte, which will result in a large amount of lithium replenishment layer 1234 The lithium will be exposed on the surface of the non-reaction zone 12321 for a long time, accelerating the consumption of electrolyte and aggravating the gas production of the secondary battery 12 .
  • the porosity of the negative electrode sheet 1232 can be increased so that the electrolyte can be fully infiltrated, thereby helping to extend the service life of the secondary battery 12.
  • the lithium supplement area of the lithium supplement layer 1234 is S 1
  • the sum of the cross-sectional areas of all through holes 12343 on the lithium supplement layer 1234 is S 2
  • S 2 satisfies the condition: 5% S 1 ⁇ S 2 ⁇ 50%S 1 .
  • the cross-sectional area of the through hole 12343 refers to the cross-sectional area parallel to the plane where the opening of the through hole 12343 is located.
  • the sum of the cross-sectional areas of all through holes 12343 refers to the sum of the cross-sectional areas of all the through holes 12343.
  • the effective lithium replenishing area of the lithium replenishing layer 1234 refers to the difference between the lithium replenishing area S 1 of the lithium replenishing layer 1234 and the sum of the cross-sectional areas S 2 of all the through holes 12343 on the lithium replenishing layer 1234 .
  • S 2 By setting S 2 to meet the conditions: 5% S 1 ⁇ S 2 ⁇ 50% S 1 , it can not only meet the demand for lithium replenishment, but also enable the electrolyte to fully infiltrate, thus helping to further improve the first performance of the secondary battery 12 Coulombic efficiency, cycle performance and storage performance.
  • S2 satisfies the condition: 20% S1 ⁇ S2 ⁇ 30% S1.
  • the electrolyte has better wetting and lithium replenishing effects.
  • the first Coulombic efficiency of the negative electrode sheet 1232 provided with the lithium supplementary layer 1234 is higher than the first Coulombic efficiency of the negative electrode sheet 1232 without the lithium supplementary layer 1234.
  • the capacity retention rate of the negative electrode sheet 1232 is higher than that of the negative electrode sheet 1232 without the lithium replenishing layer 1234 .
  • Q1 and Q2 increase, the first Coulomb efficiency and capacity retention rate of the negative electrode sheet 1232 increase.
  • the sum of the cross-sectional areas of all the through holes 12343 on the lithium supplement layer 1234 increases as a percentage of the lithium supplement area of the lithium supplement layer 1234, the first Coulombic efficiency and capacity retention rate of the negative electrode sheet 1232 increase.
  • the present application also provides a battery 10, which includes the secondary battery 12 as described in any of the above embodiments.
  • the present application provides an electrical device, including the battery 10 as described in any of the above embodiments.
  • the battery 10 is used to provide electric energy, or includes the secondary battery 12 as described in any of the embodiments.
  • the secondary battery 12 is used to provide electric energy.
  • the present application provides a secondary battery 12.
  • the secondary battery 12 includes an electrode assembly 123.
  • the electrode assembly 123 includes at least one positive electrode sheet 1231 and at least one negative electrode sheet 1232.
  • the at least one negative electrode sheet 1232 There is a non-reactive area 12321 on the negative electrode film layer.
  • the non-reactive area 12321 is not opposite to the positive electrode film layer on the positive electrode sheet 1231 adjacent to the negative electrode sheet 1232, and at least one non-reactive area 12321 is provided with a lithium supplement layer. 1234; wherein, the total capacity of the secondary battery 12 is Q, the total lithium replenishing capacity of all lithium replenishing layers 1234 is Q Li , and Q Li satisfies the condition: 2% Q ⁇ Q Li ⁇ 6% Q.

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Abstract

本申请涉及一种二次电池、电池及用电装置，二次电池包括电极组件，电极组件包括：至少一个正极片及至少一个负极片，至少一个负极片的负极膜层上具有非反应区，非反应区和与其所在的负极片相邻设置的正极片上的正极膜层不相对设置，且至少一个非反应区上设有补锂层；其中，二次电池的总容量为Q，所有补锂层补锂的总容量为Q Li，Q Li满足条件：0.5％Q≤Q Li≤10％Q。本申请提供的二次电池、电池及用电装置首次库伦效率、循环性能和存储性能较高。

Description

二次电池、电池及用电装置 技术领域
本申请涉及电池技术领域，特别是涉及一种二次电池、电池及用电装置。
背景技术
近年来，随着锂离子电池的应用范围越来越广泛，锂离子电池广泛应用于水力、火力、风力和太阳能电站等储能电源***，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于锂离子电池取得了极大的发展，因此，对其首次库伦效率、循环性能和存储性能等也提出了更高的要求。
当锂离子电池开始充电后，正极片的锂离子嵌入负极片，但是，在放电的过程中，负极片上嵌入的锂离子中的部分很难回到正极片，这就造成了正极片的不可逆锂损失，恶化电芯的首次库伦效率、循环性能和存储性能。因此，现有的锂离子电池在首次库伦效率、循环性能和存储性能等方面仍有待改进。
发明内容
鉴于上述问题，本申请提供一种二次电池、电池及用电装置，能够提升二次电池、电池及用电装置的首次库伦效率、循环性能和存储性能。
第一方面，本申请提供了一种二次电池，包括电极组件，电极组件包括：至少一个正极片及至少一个负极片，至少一个负极片的负极膜层上具有非反应区，非反应区和与其所在的负极片相邻设置的正极片上的正极膜层不相对设置，且至少一个非反应区上设有补锂层；
其中，二次电池的总容量为Q，所有补锂层补锂的总容量为Q Li，Q Li满足条件：0.5％Q≤Q Li≤10％Q。
在本申请中，注液前将锂源置于非反应区的负极膜层的表面上并形成补锂层，补锂层上的锂，和与补锂层重叠的负极膜层的形成材料如石墨或硅碳材料之间存在大约3V左右的电位差，且锂的电压低于承载其的未嵌锂的负极膜层的形成材料的电压。当二次电池12注液后，由于补锂层与承载其的负极膜层的非反应区是紧密贴合的状态，所以，补锂层与承载其的负极膜层之间形成电回路，相当于直接短路的状态(在此状态下，补锂层为负极，承载补锂层的负极膜层为正极)，在它们电位差的作用下，补锂层中的锂会失去电子变成自由移动的锂离子嵌入承载其的负极膜层中，并与负极膜层中的C(碳)形成LiCx(x≥6)，或/和，和承载其的负极膜层中的Si(硅)形成LixSiy(x>0,y>0)。此时原始的补锂层、LiCx和/或LixSiy组合形成了新的稳定的补锂层。
新的稳定的补锂层电位较低，由于锂离子是由电位较低的区域向电位较高的区域嵌入，如此，在充电的过程中，新的稳定的补锂层能够有效地阻止同一负极片上的反应区的锂离子向非反应区扩散并嵌入，且在放电过程中，负极片的反应区的电位逐渐升高，这时反应区的电位远远高于非反应区的电位，新的稳定的补锂层中的锂离子会在此电位差的驱动下以缓慢的速度向反应区扩散，从而改善二次电池的首次库伦效率、循环性能和存储性能。
在一些实施例中，补锂层为锂金属单质层。
由硅锂合金、铝锂合金、镁锂合金、锡锂合金等锂合金制作形成的补锂层中锂合金的克容量相对较低，脱锂后会形成金属杂质，有恶化二次电池安全性能的风险。而锂金属单质层中锂金属单质理论克容量高，且反应后残留物较少，它不但能提升二次电池的首效、循环以及存储性能还不会降低二次电池的能量密度。
在一些实施例中，Q Li满足条件：2％Q≤Q Li≤6％Q。
基于上述考虑，优选将补锂层的补锂量控制在：2％Q≤Q Li≤6％Q的范围内。在2％Q≤Q Li≤6％Q的范围内时，不但可以提升二次电池的首次库伦效率、循环性能及存储性能，同时，还具有较高的补锂层的利用率。
在一些实施例中，电极组件包括隔离膜，电极组件被构造为由正极片、隔离膜及负极片层叠设置形成的叠片结构；
在所有的正极片与所有的负极片中，最外层的负极片中最外层的负极膜层的表面形成非反应区，补锂层覆盖非反应区。
通过最外层的负极片中最外层的负极膜层设置补锂层，且补锂层覆盖非反应区，可以有效提升补锂层的补锂面积，从而使得叠片结构的电极组件具有较高的首次库伦效率、循环性能及存储性能。
在一些实施例中，电极组件包括隔离膜，电极组件被构造为由正极片、隔离膜及负极片卷绕形成的卷绕结构；
电极组件包括起始卷绕段及收尾卷绕段，起始卷绕段的所有正极片与所有负极片1232中，最内层的负极片中最内层的负极膜层的表面，和/或收尾卷绕段的所有正极片与所有负极片中，最外层的负极片中最外层的负极膜层的表面形成有非反应区，起始卷绕段及收尾卷绕段中至少一者上的非反应区设有补锂层。
在该实施例中，电极组件的起始卷绕段及收尾卷绕段均有可能设置非反应区。非反应区位点越多越利于补锂层的分配，从而可根据需要选择设置补锂层的位置。
在一些实施例中，起始卷绕段及收尾卷绕段中的每个非反应区均设有补锂层，设于起始卷绕段上的所有补锂层的补锂总容量为Q 1，设于收尾卷绕段上的所有补锂层的补锂总容量为Q 2，Q Li＝Q 1+Q 2，且Q 1＞Q 2。
由于起始卷绕段相较于收尾卷绕段位于电极组件的中心，则当起始卷绕段被电解液 充分浸润后保液能力远高于收尾卷绕段。这样，更有利于补锂层中锂离子的扩散，以进一步改善电芯的首次库伦效率、循环以及存储性能。
在一些实施例中，所有补锂层的补锂总面积为S Li，每个负极片1232单侧的负极膜层中单位面积的容量为C 负，S Li满足条件：Q Li/120％C 负≤S Li≤Q Li/20％C 负。
负极片上的非反应区的电位高低与非反应区的补锂面积有直接关系。补锂面积越大，负极片上非反应区的电位降低程度越大，那么，整个负极片的电位也将降低。这样，负极片和与该负极片相邻设置的正极片之间的电位差也会更大。根据能量＝电位差X容量的公式，电位差越大，则二次电池的能量也越大。因此，在该种设计下，二次电池具有较高的能量密度。
在一些实施例中，S Li满足条件：Q Li/90％C 负≤S Li≤Q Li/50％C 负。
在该范围内，二次电池内的补锂面积较为合适，利用率较高，可以有效提升二次电池的首次库伦效率、循环性能及存储性能。
在一些实施例中，补锂层包括：
多个第一补锂单元，沿所在的负极片的纵长方向间隔设置；和/或
多个第二补锂单元，沿所在的负极片的横向间隔设置。
在该种实施例中，任意相邻的两个第一补锂单元之间，和/或任意相邻的两个第二补锂单元之间均存在间隙。间隙的设置，使得电解液可以充分浸润至非反应区，这样，补锂层可以快速嵌入至与其重叠的负极膜层并形成新的稳定的补锂层，新的稳定的补锂层可以缓慢的补充锂离子，从而有助于延长二次电池的使用寿命。
在一些实施例中，每个第一补锂单元沿所在的负极片的横向延伸至该负极片相对的两边缘。
在该种设计下，能够充分利用非反应区的空间设置第一补锂单元，以使得第一补锂单元具有较大的长度，随之，第一补锂单元的补锂容量也增加，使得二次电池具有较好的补锂效果。此外，每相邻的两个第一补锂单元之间形成的间隙还可保障电解液能够充分浸润。
在一些实施例中，每个第二补锂单元包括多个补锂部，每个补锂部均为块状，每个第二补锂单元的所有补锂部沿所在的负极片的纵长方向间隔设置。
在该种实施例中，能够进一步保障电解液的充分浸润。
在一些实施例中，补锂层被构造为沿其所在的负极片的纵长方向连续延伸的层结构。
这样，负极片上具有较大的补锂面积，则负极片和与该负极片相邻设置的正极片之间的电位差也会更大。根据能量＝电位差X容量的公式，电位差越大，则二次电池的能量也越大，随之，二次电池的循环性能及存储性能也可以随之提升。
在一些实施例中，补锂层上开设有多个通孔。
而通过设置多个通孔，可以增加负极片的孔隙率，以使得电解液可以充分浸润，从而有助于延长二次电池的使用寿命。
在一些实施例中，补锂层的补锂面积为S 1，补锂层上所有所述通孔的横截面积总和为S 2，S 2满足条件：5％S 1≤S 2≤50％S 1。
通过设置S 2满足条件：5％S 1≤S 2≤50％S 1，在能够满足补锂需求的同时，还使得电解液能够充分进行浸润，从而有助于进一步提升二次电池的首次库伦效率、循环性能及存储性能。
在一些实施例中，S 2满足条件：20％S 1≤S 2≤30％S 1。
在该种实施例下，电解液具有较优的浸润及补锂效果。
第二方面，本申请提供了一种电池，其包括如上述任一项实施例所述的二次电池。
第三方面，本申请提供了一种用电装置，其包括如上述实施例所述的电池，电池用于提供电能；或者，包括如上述任一项实施例所述的二次电池，二次电池用于提供电能。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：
图1为本申请一些实施例中车辆的结构示意图；
图2为本申请一些实施例中电池的***图；
图3为本申请一些实施例中二次电池的***图；
图4为本申请一些实施例中电极组件为卷绕结构的剖面图；
图5为图4所示的一实施例中电极组件的负极片的展开示意图；
图6为图4所示的另一实施例中电极组件的负极片的展开示意图；
图7为图4所示的又一实施例中电极组件的负极片的展开示意图；
图8为图4所示的再一实施例中电极组件的负极片的展开示意图。
附图说明：
1、车辆；10、电池；11、箱体；111、第一部分；112、第二部分；12、二次电池；121、壳体；122、端盖；123、电极组件；1231、正极片；1232、负极片；12321、非反应区；12322、反应区；1233、隔离膜；1234、补锂层；12341、第一补锂单元；12342、第二补锂单元；123421、补锂部；12343、通孔；20、控制器；30、马达。
具体实施方式
为使本申请的上述目的、特征和优点能够更加明显易懂，下面结合附图对本申请的具体实施方式做详细的说明。在下面的描述中阐述了很多具体细节以便于充分理解本申请。但是本申请能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本申请内涵的情况下做类似改进，因此本申请不受下面公开的具体实施例的限制。
在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。
在本申请中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系，除非另有明确的限定。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在本申请中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
目前，从市场形势的发展来看，电池的应用越加广泛。电池不仅被应用于水力、火力、风力和太阳能电站等储能电源***，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。随着电池应用领域的不断扩大，其市场的需求量也在不断地扩增。
本申请人注意到，当锂离子电池开始充电后，正极片的锂离子优先嵌入负极片1232的反应区，使得反应区的电位下降，与负极片1232的非反应区形成电位差，反应区的锂离子以缓慢的速度向非反应区扩散嵌入，而嵌入非反应区的锂离子在放电过程中很难回到正极 片，这就造成了正极片的不可逆锂损失，恶化电芯的首次库伦效率、循环性能和存储性能。因此，现有的锂离子电池在首次库伦效率、循环性能和存储性能等方面仍有待改进。
为了解决现有的锂离子电池在首次库伦效率、循环性能和存储性能不佳的问题，申请人经过深入研究，设计了一种二次电池，在该二次电池中，电极组件包括：至少一个正极片及至少一个负极片1232，至少一个负极片1232的负极膜层上具有非反应区，非反应区和与其所在的负极片1232相邻设置的正极片上的正极膜层不相对设置，且至少一个非反应区上设有补锂层；其中，二次电池的总容量为Q，所有补锂层补锂的总容量为Q Li，Q Li满足条件：0.5％Q≤Q Li≤10％Q。
其中，在同一个负极片1232中，在设有非反应区的同一个负极膜层上，或者在与设有非反应区的负极膜层相背设置的负极膜层上，还设有反应区，反应区和与其所在的负极片1232相邻设置的正极片上的正极膜层相对设置。在充放电的过程中，反应区和与其相对设置的正极膜层之间发生脱嵌锂。
在本申请中，注液前将锂源置于非反应区上并形成补锂层，补锂层上的锂，和与补锂层重叠的负极膜层的形成材料如石墨或硅碳材料之间存在大约3V左右的电位差，且锂的电位低于重叠的负极膜层的形成材料的电位。当二次电池注液后，由于补锂层和与其重叠的负极膜层的非反应区是紧密贴合的状态，所以，补锂层和与其重叠的负极膜层之间形成电回路，相当于直接短路的状态(在此状态下，补锂层为负极，与补锂层重叠的负极膜层为正极)，在电位差的作用下，补锂层中的锂会失去电子变成自由移动的锂离子嵌入与补锂层重叠的负极膜层中，并与负极膜层中的C(碳)形成LiCx(x≥6)，或/和，和与补锂层重叠的负极膜层中的Si(硅)形成LixSiy(x>0,y>0)。此时原始的补锂层、LiCx和/或LixSiy组合形成了新的稳定的补锂层。
新的稳定的补锂层使得非反应区的电位较低，由于锂离子是由电位较低的区域向电位较高的区域嵌入，如此，在充电的过程中，新的稳定的补锂层能够有效地阻止同一负极片1232上的反应区的锂离子向非反应区扩散并嵌入，且在放电过程中，负极片1232的反应区的电位逐渐升高，这时反应区的电位远远高于非反应区的电位，新的稳定的补锂层中的锂离子会在电位差的驱动下以缓慢的速度向反应区扩散，从而改善二次电池的首次库伦效率、循环性能和存储性能。
而且，Q Li满足条件：0.5％Q≤Q Li≤10％Q，补锂层补锂的总容量位于该范围内，还具有较好的补锂效果，能够进一步提升二次电池的首次库伦效率、循环性能和存储性能。
请参阅图1、图2、图3及图4，本申请实施例公开的二次电池12可以但不限用于车辆1、船舶或飞行器等用电装置中。可以使用具备本申请公开的二次电池12、电池10等组成该用电装置的电源***，这样，针对负极片1232的非反应区12321设置补锂层，有利于提升电池10的首次库伦效率、循环性能和存储性能。
本申请实施例提供一种使用电池10作为电源的用电装置，用电装置可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
以下实施例为了方便说明，以本申请一实施例的一种用电装置为车辆1为例进行说明。
请再次参阅图1，车辆1可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1的内部设置有电池10，电池10可以设置在车辆1的底部或头部或尾部。电池10可以用于车辆1的供电，例如，电池10可以作为车辆1的操作电源。车辆1还可以包括控制器20和马达30，控制器20用来控制电池10为马达30供电，例如，用于车辆1的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池10不仅可以作为车辆1的操作电源，还可以作为车辆1的驱动电源，代替或部分地代替燃油或天然气为车辆1提供驱动动力。
请再次参阅图2，电池10包括箱体11和二次电池12，二次电池12容纳于箱体11内。其中，箱体11用于为二次电池12提供容纳空间，箱体11可以采用多种结构。在一些实施例中，箱体11可以包括第一部分111和第二部分112，第一部分111与第二部分112相互盖合，第一部分111和第二部分112共同限定出用于容纳二次电池12的容纳空间。第二部分112可以为一端开口的空心结构，第一部分111可以为板状结构，第一部分111盖合于第二部分112的开口侧，以使第一部分111与第二部分112共同限定出容纳空间；第一部分111和第二部分112也可以是均为一侧开口的空心结构，第一部分111的开口侧盖合于第二部分112的开口侧。当然，第一部分111和第二部分112形成的箱体11可以是多种形状，比如，圆柱体、长方体等。
在电池10中，二次电池12可以是多个，多个二次电池12之间可串联或并联或混联，混联是指多个二次电池12中既有串联又有并联。多个二次电池12之间可直接串联或并联或混联在一起，再将多个二次电池12构成的整体容纳于箱体11内；当然，电池10也可以是多个二次电池12先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体11内。电池10还可以包括其他结构，例如，该电池10还可以包括汇流部件，用于实现多个二次电池12之间的电连接。
请再次参阅图3，二次电池12是指组成电池10的最小单元。如图3，二次电池12包括有端盖122、壳体121、电极组件123以及其他的功能性部件。
端盖122是指盖合于壳体121的开口处以将二次电池12的内部环境隔绝于外部环境的部件。不限地，端盖122的形状可以与壳体121的形状相适应以配合壳体121。具体地，端盖122可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖122在受挤压碰 撞时就不易发生形变，使二次电池12能够具备更高的结构强度，安全性能也可以有所提高。端盖122上可以设置有如电极端子等的功能性部件。电极端子可以用于与电极组件123电连接，以用于输出或输入二次电池12的电能。在一些实施例中，端盖122上还可以设置有用于在二次电池12的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖122的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖122的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体121内的电连接部件与端盖122，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体121是用于配合端盖122以形成二次电池12的内部环境的组件，其中，形成的内部环境可以用于容纳电极组件123、电解液以及其他部件。壳体121和端盖122可以是独立的部件，可以于壳体121上设置开口，通过在开口处使端盖122盖合开口以形成二次电池12的内部环境。不限地，也可以使端盖122和壳体121一体化，具体地，端盖122和壳体121可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体121的内部时，再使端盖122盖合壳体121。壳体121可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体121的形状可以根据电极组件123的具体形状和尺寸大小来确定。壳体121的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
请再次参阅图4，并同时参阅图5，电极组件123是二次电池12中发生电化学反应的部件。壳体121内可以包含一个或更多个电极组件123。电极组件123主要由正极片1231和负极片1232卷绕或层叠放置形成，并且通常在正极片1231与负极片1232之间设有隔离膜1233。
根据本申请的一些实施例，二次电池12包括电极组件123，电极组件123包括：至少一个正极片1231及至少一个负极片1232，至少一个负极片1232的负极膜层上具有非反应区12321，非反应区12321和与其所在的负极片1232相邻设置的正极片1231上的正极膜层不相对设置，且至少一个非反应区上12321设有补锂层1234；其中，二次电池12的总容量为Q，所有补锂层1234补锂的总容量为Q Li，Q Li满足条件：0.5％Q≤Q Li≤10％Q。
其中，电极组件123还包括隔离膜1233，正极片1231、隔离膜1233及负极片1232依次层叠设置，且正极片1231与负极片1232之间可以为交替设置，也可以为非交替设置。交替设置是指按照正极片1231、隔离膜1233、负极片1232、隔离膜1233、正极片1231、隔离膜1233、负极片1232……的层叠方式，或者按照负极片1232、隔离膜1233、正极片1231、隔离膜1233、负极片1232、隔离膜1233、正极片1231......的层叠方式。非交替设置是指存在同一种极片为相邻设置的层叠方式。比如，非交替方式可以为正极片1231、正极片1231、隔离膜1233、负极片1232、隔离膜1233、正极片1231、正极片1231、隔离膜 1233、负极片1232......的设置方式。相邻设置的两个负极片1232之间、以及相邻的两个正极片1232之间可以选择设置隔离膜1233，或者选择不设置隔离膜1233。具体地，选用厚度为12μm聚乙烯膜作为隔离膜1233。
正极片1231包括正极集流体及沿正极集流体的厚度方向设于正极集流体相对的两侧的正极膜层。正极片的制备过程具体为：将磷酸铁锂、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按质量比96:2:2进行混合，加入溶剂N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌至体系呈均一状，获得正极浆料。而后，将正极浆料均匀涂覆在厚度为12μm的正极集流体的两个表面上，并经115℃干燥15min的高温条件，冷压得到厚度为84μm的正极膜层，然后通过分切得到长605mm、膜宽为88mm的正极片1231，涂布重量为20mg/cm2，压实密度为2.4g/cm 3。
负极片1232包括负极集流体及沿负极集流体的厚度方向设于负极集流体相对的两侧的负极膜层。负极片1232的制备过程具体为：将人造石墨、导电剂乙炔黑、增稠剂羧甲基纤维素钠(CMC)、粘结剂SBR按质量比96.4:1:1.2:1.4进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得负极浆料；将负极浆料均匀涂覆在厚度为8μm的负极集流体的两个表面上，在115℃干燥15min，冷压得到单侧厚度为61μm的负极膜层，分切得到长735mm、膜宽为93mm的负极片1232，负极片1232的涂布重量为9.4mg/cm 2，压实密度为1.55g/cm 3。
每个负极片1232的一侧或者相对的两侧具有与之相邻设置的正极片1231，负极片1232与正极片1231相邻设置是指负极片1232与正极片1231层叠设置于同一隔离膜1233的相对两侧。每个负极片1232中的至少一个负极膜层上具有反应区12322，至少一个负极片1232的负极膜层上具有非反应区12321。相对的两侧具有相邻设置的正极片1231的负极片1232上的每个负极膜层上仅设置反应区12322，仅一侧具有相邻设置的正极片1231的负极片1232上朝向该正极片1231的负极膜层上设置反应区12322，在同一负极片1232中，该负极膜层和/或与该负极膜层相背设置的负极膜层上设置非反应区12321。也就是说，在仅一侧具有与之相邻设置的正极片1231的负极片1232中，该负极片1232朝向与之相邻的正极片1231的负极膜层上可以仅设置反应区12322，也可能同时设置反应区12322与非反应区12321，该负极片1232背向与之相邻的正极片1231的负极膜层上仅能设置非反应区12321。在相对的两侧均具有与之相邻设置的正极片1231的负极片1232中，该负极片1232的每个负极膜层上均只能设置反应区12322。由此可见，非反应区12321仅位于一侧具有与之相邻设置的正极片1231的负极片1232上。在同一个负极片1232中，反应区12322与非反应区12321可以位于同一负极膜层上，也可以位于不同的负极膜层上，且反应区12322及非反应区12321位于各自所在的负极膜层背向负极集流体的表面。
在同时具有反应区12322及非反应区12321的负极片1232中，反应区12322和与其 所在的负极片1232相邻设置的正极片1231上的正极膜层相对设置，非反应区12321和与其所在的负极片1232相邻设置的正极片1231上的正极膜层不相对设置。充放电的过程中，反应区12322与该正极片1231相对设置的正极膜层之间直接发生脱嵌锂，非反应区12321与该正极片1231的正极膜层之间不直接发生脱嵌锂。
其中，反应区12322和与其所在的负极片1232相邻设置的正极片1231上的正极膜层相对设置是指：在忽略位于反应区12322与正极膜层之间的隔离膜1233的情况下，反应区12322与正极片1231相互朝向设置，且反应区12322与正极膜层在正极片1231与负极片1232的层叠方向上的投影完全重合。非反应区12321和与其所在的负极片1232相邻设置的正极片1231上的正极膜层不相对设置是指：非反应区12321与正极片1231的正极膜层相互朝向设置，且非反应区12321与正极膜层在正极片1231与负极片1232的层叠方向上的投影完全不重合，和/或非反应区12321与正极片1231的正极膜层背向设置，至于非反应区12321与正极膜层在正极片1231与负极片1232的层叠方向上的投影是否重合不做具体限定。具体地，当反应区12322及非反应区12321均位于负极片1232中朝向正极片1231的正极膜层的负极膜层时，非反应区12321与正极膜层在正极片1231与负极片1232的层叠方向上的投影完全不重合；当反应区12322及非反应区12321均位于负极片1232中不同的负极膜层时，反应区12322与正极片1231相互朝向设置，且反应区12322与正极膜层在正极片1231与负极片1232的层叠方向上的投影完全重合，非反应区12321与正极片1231的正极膜层背向设置。
以电极组件123为叠片结构为例，在所有的正极片1231与所有的负极片1232中，最外层的负极片1232中背向与之相邻设置的正极片1231上正极膜层的负极膜层的表面形成非反应区12321。
比如，电极组件123包括两个正极片1231、两个负极片1232及三个隔离膜1233，在层叠方向上，电极组件123按照正极片1231、隔离膜1233、负极片1232、隔离膜1233、正极片1231、隔离膜1233、负极片1232的方式排列。在层叠方向上，第一个负极片1232位于两个正极片1231之间，故第一个负极片1232不存在非反应区12321。在所有的正极片1231与所有的负极片1232中，第二个负极片1232为位于最外层的负极片1232，第二个负极片1232背向与之相邻的第二个正极片1231正极膜层的负极膜层的表面形成非反应区12321。
请再次参阅图4，以电极组件123为卷绕结构为例，电极组件123包括起始卷绕段、收尾卷绕段及连接于起始卷绕段与收尾卷绕段之间的中间卷绕段，起始卷绕段的所有正极片1231与所有负极片1232中，位于最内层的负极片1232(如图4中包括由箭头j、箭头O、箭头p、箭头K、箭头l、箭头m、箭头r、箭头n所在位置的各段组合形成的负极片1232)中最内层的负极膜层的表面，和/或收尾卷绕段的所有正极片1231与所有负极片1232中， 位于最外层的负极片1232(如图4中包括由箭头a、箭头b、箭头c、箭头d、箭头e、箭头f、箭头g、箭头h所在位置的各段组合形成的负极片1232)中最外层的负极膜层的表面均可形成非反应区12321。
也就是说，当起始卷绕段中存在最内层的负极片1232时，该负极片1232中最内层的负极薄膜的表面形成非反应区12321，当收尾卷绕段中存在最外层的负极片1232时，该负极片1232中最外层的负极膜层的表面形成非反应区12321。位于起始卷绕段中其他的负极片1232，位于收尾卷绕段中其他的负极片1232，以及中间卷绕段中的所有负极片1232的每侧均具有与之相邻的正极片1231，该段中的每个负极片1232的每个负极膜层的表面仅可以形成反应区12322。
其中，起始卷绕段的最内层的负极片1232是指：起始卷绕段的所有正极片1231与所有负极片1232中，最靠近卷绕中心线的一层负极片1232；起始卷绕段中最内层的负极片1232中最内层的负极膜层是指：起始卷绕段中最内层的负极片1232最靠近卷绕中心线的一层负极膜层。
收尾卷绕段的最外层的负极片1232是指：收尾卷绕段的所有正极片1231与所有负极片1232中，最远离卷绕中心线的一层负极片1232。收尾卷绕段中最外层的负极片1232中最外层的负极膜层是指：收尾卷绕段的最外层的负极片1232最远离卷绕中心线的一层负极膜层。
其中，定义电极组件123为N圈，N＞5且N为自然数，起始卷绕段(以如图4中包括由箭头j、箭头O、箭头p、箭头K、箭头l、箭头m、箭头r、箭头n所在位置的各段组合形成的负极片1232作为最内层的负极片1232的一段)由第1圈组成，或者由连续设置的第1圈和部分第2圈组成，或者，也可以由第1圈和第2圈组成，收尾卷绕段(以如图4中包括由箭头a、箭头b、箭头c、箭头d、箭头e、箭头f、箭头g、箭头h所在位置的各段组合形成的负极片1232作为最外层的负极片1232的一段)由最后1圈，或者连续设置的最后1圈及部分倒数第2圈组成，或者，也可以由最后1圈和倒数第2圈组成。中间圈为连接于起始卷绕段与收尾卷绕段之间的所有圈层的总成。
起始卷绕段及收尾卷绕段至少一者中的负极片1232具有非反应区12321，起始卷绕段及收尾卷绕段中的至少一个非反应区12321设有补锂层1234。
在电极组件123为叠片结构的实施例中，非反应区12321可以为负极片1232上不具有与之相邻的正极片1231的一侧负极膜层表面的整个区域，或者部分区域。在电极组件123为卷绕结构的实施例中，非反应区12321为负极片1232上不具有与之相邻的正极片1231的一侧负极膜层表面的部分区域。
补锂层1234是指能向正极片1231内部补充锂离子的物质，比如：补锂层1234可为但不限于补锂层为能提供活性锂的物质，包括但不限于以下几种，如锂箔、锂粉、硅锂合 金、铝锂合金、镁锂合金、锡锂合金等。另外，补锂层1234可通过压延、沉积或者粘接的方式，其中，沉积方式可为但不限于磁控溅射沉积方式等。
在本申请中，注液前将锂源置于非反应区12321的负极膜层的表面上并形成补锂层1234，补锂层1234上的锂，和与补锂层重叠的负极膜层的形成材料如石墨或硅碳材料之间存在大约3V左右的电位差，且锂的电压低于承载其的未嵌锂的负极膜层的形成材料的电压。当二次电池12注液后，由于补锂层1234与承载其的负极膜层的非反应区是紧密贴合的状态，所以，补锂层1234与承载其的负极膜层之间形成电回路，相当于直接短路的状态(在此状态下，补锂层1234为负极，承载补锂层1234的负极膜层为正极)，在它们电位差的作用下，补锂层1234中的锂会失去电子变成自由移动的锂离子嵌入承载其的负极膜层中，并与负极膜层中的C(碳)形成LiCx(x≥6)，或/和，和承载其的负极膜层中的Si(硅)形成LixSiy(x>0,y>0)。此时原始的补锂层、LiCx和/或LixSiy组合形成了新的稳定的补锂层。
新的稳定的补锂层电位较低，由于锂离子是由电位较低的区域向电位较高的区域嵌入，如此，在充电的过程中，新的稳定的补锂层1234能够有效地阻止同一负极片1232上的反应区12322的锂离子向非反应区12321扩散并嵌入，且在放电过程中，负极片1232的反应区12322的电位逐渐升高，这时反应区12322的电位远远高于非反应区12321的电位，新的稳定的补锂层1234中的锂离子会在此电位差的驱动下以缓慢的速度向反应区12322扩散，从而改善二次电池12的首次库伦效率、循环性能和存储性能。
根据本申请的一些实施例，补锂层1234为锂金属单质层。
比如，锂金属单质可以为锂箔、锂粉等。锂箔的加工性能优于锂粉，所以优选锂箔作为补锂层1234。
以补锂层1234为锂箔为例，锂箔的制作过程如下：
第一步：设计二次电池12的总容量Q，Q单位为安时(Ah)，其中，总容量Q的计算方式为：总容量Q＝(E*1000)÷n÷V，E为用电装置中电池10的能量，单位为千瓦时(KW.h)，n为用电装置中电池10中二次电池12的总数量(直接数就可以)，V为单个二次电池12的电压，单位为伏特(v)；
第二步：根据二次电池12的总容量计算出需要补锂的总容量Q Li；
第三步：利用扣式对二次电池12进行测试，以测出每个负极片1232单侧的膜层中单位面积的容量为C 负，单位为安时/平方厘米(Ah/cm 2)；
第四步：算出锂箔的补锂总面积S Li＝Q Li÷X％C 负(20％≤X≤120％)；
第五步：计算出需要补锂的总重量W Li＝Q Li÷3860Ah/g(锂的克容量)；
第六步：计算出锂箔的平均厚度H Li＝W Li÷锂的密度÷S Li；
第七步：用辊压机将锂箔压延至第六步计算出的厚度，生产出符合理论设计的锂 箔；
第八步：将第七步生产出的锂箔按锂箔的补锂总面积S Li裁出需要的长度及宽度的锂箔，并将其设置于负极片1232的非反应区12321。
由硅锂合金、铝锂合金、镁锂合金、锡锂合金等锂合金制作形成的补锂层1234中锂合金的克容量相对较低，脱锂后会形成金属杂质，有恶化二次电池12安全性能的风险。而锂金属单质层中锂金属单质理论克容量高，且反应后残留物较少，它不但能提升二次电池12的首效、循环以及存储性能还不会降低二次电池12的能量密度。
根据本申请的一些实施例，2％Q≤Q Li≤6％Q。
通过实验发现，当补锂层1234的利用率随着补锂量的增加逐渐在减小，当补锂量超过二次电池12总容量的10％后，利用率的减小幅度增大，且锂金属的副反应会加重。而若补锂层1234的补锂量过少，则无法有效进行补锂。
基于上述考虑，优选将补锂层1234的补锂量控制在：2％Q≤Q Li≤6％Q的范围内。在2％Q≤Q Li≤6％Q的范围内时，不但可以提升二次电池12的首次库伦效率、循环性能及存储性能，同时，还具有较高的补锂层1234的利用率。
根据本申请的一些实施例，电极组件123包括隔离膜1233，电极组件123被构造为由正极片1231、隔离膜1233及负极片1232层叠设置形成的叠片结构；在所有的正极片1231与所有的负极片1232中，最外层的负极片1232中最外层的负极膜层的表面形成非反应区12321，补锂层1234覆盖非反应区12321。
其中，补锂层1234可以全部覆盖非反应区12321，也可以部分覆盖非反应区12321，具体可根据补锂需求进行设置。
在该实施例中，在所有的正极片1231与所有的负极片1232中，位于中间层的负极片1232的负极膜层不具备非反应区12321，位于最外层的负极片1232的最外层的负极膜层的表面具有非反应区12321。最外层的负极片1232中最外层的负极膜层是指最外层的负极片1232背向与之相邻的正极片1231设置的负极膜层。
其中，在所有的正极片1231与所有的负极片1232中，最外层的负极片1232是指沿层叠方向设置在第一层叠位置的负极片1232以及最后层叠位置的负极片1232。其中，层叠位置是指电极组件123中每个极片所在的位置，以电极组件123包括一个正极片1231、一个隔离膜1233及一个负极片1232，且在层叠方向上，正极片1231、隔离膜1233及负极片1232依次布设为例，正极片1231处于第一层叠位置，负极片1232处于最后层叠位置。中间层的负极片1232是指位于第一层叠位置及最后层叠位置之间的层叠位置的负极片1232。
在叠片结构的电极组件123中，存在位于第一层叠位置和/或最后层叠位置的最外层的负极片1232。比如，以电极组件123沿层叠方向按照正极片1231(位于第一层叠位置)、隔离膜1233、负极片1232(位于第二层叠位置)、隔离膜1233、正极片1231(位于第三层叠位 置)、隔离膜1233及负极片1232(位于最后层叠位置)层叠设置为例，在该实施例中，位于第二层叠位置的负极片1232为中间层的负极片1232，位于最后层叠位置的负极片1232为最外层的负极片1232，且位于最后层叠位置的负极片1232背向位于第三层叠位置的负极膜层为最外层的负极片1232中最外层的负极膜层。又比如，以电极组件123沿层叠方向按照隔离膜1233、负极片1232(位于第一层叠位置)、隔离膜1233、正极片1231(位于第二层叠位置)、隔离膜1233、负极片1232(位于最后层叠位置)及隔离膜1233层叠设置为例，在该实施例中，位于第一层叠位置以及最后层叠位置上的负极片1232均为最外层的负极片1232。位于第一层叠位置的负极片1232背向位于第二层叠位置的正极片1231的负极膜层，以及位于最后层叠位置的负极片1232背向位于第二层叠位置的正极片1231的负极膜层均为最外层的负极片1232中最外层的负极膜层。
通过最外层的负极片1232中最外层的负极膜层设置补锂层1234，且补锂层1234覆盖非反应区12321，可以有效提升补锂层1234的补锂面积，从而使得叠片结构的电极组件123具有较高的首次库伦效率、循环性能及存储性能。
请再次参阅图4及图5，根据本申请的一些实施例，电极组件123包括隔离膜1233，电极组件123被构造为由正极片1231、隔离膜1233及负极片1232卷绕形成的卷绕结构；电极组件123包括起始卷绕段及收尾卷绕段，起始卷绕段的所有正极片1231与所有负极片1232中，最内层的负极片1232中最内层的负极膜层的表面，和/或收尾卷绕段的所有正极片1231与所有负极片1232中，最外层的负极片1232中最外层的负极膜层的表面形成有非反应区12321，起始卷绕段及收尾卷绕段中至少一者上的非反应区12321设有补锂层1234。
在该实施例中，位于起始卷绕段的最内层的负极片1232中最内层的负极薄膜，以及位于收尾卷绕段的最外层的负极片1232中最外层的负极膜层的表面均具有非反应区12321，其他负极片1232片上均仅具有反应区12322。
以电极组件123包括一个正极片1231、一个隔离膜1233及一个负极片1232，且三者沿层叠方向依次层叠设置后卷绕形成卷绕结构的电极组件123，正极片1231相对负极片1232更靠近卷绕中心线。在该实施例中，起始卷绕段及收尾卷绕段中均具有正极片1231、隔离膜1233及负极片1232，且起始卷绕段、中间卷绕段及收尾卷绕段中均具有正极片1231、隔离膜1233及负极片1232，且每段中的正极片1231均相对负极片1232靠近卷绕中心线设置。在该实施例中，仅收尾卷绕段的最外层的负极片1232具有非反应区。
以电极组件123包括两个负极片1232、两个隔离膜1233及一个正极片1231，且沿层叠方向按照负极片1232、隔离膜1233、正极片1231、隔离膜1233、负极片1232的方式沿层叠方向层叠设置后卷绕形成卷绕结构的电极组件123，负极片1232相对正极片1231更靠近卷绕中心线。在该实施例中，起始卷绕段及收尾卷绕段中均具有两个负极片1232、两 个隔离膜1233及一个正极片1231，且每段中的负极片1232均相对正极片1231靠近卷绕中心线设置。在该实施例中，展开时沿层叠方向设置的第一个负极片1232位于起始卷绕段中的一段，形成起始卷绕段的所有正极片1231与所有负极片1232中最内层的负极片1232，展开时沿层叠方向设置的第二个负极片1232位于收尾卷绕段中的一段，形成收尾卷绕段的所有正极片1231与所有负极片1232中最外层的负极片1232。
请再次参阅图4，在图4中，电极组件123仅包括一个负极片1232、一个正极片1231及一个隔离膜1233为例，且沿层叠方向按照负极片1232、隔离膜1233、正极片1231的层叠方式层叠设置后卷绕形成卷绕结构的电极组件123，负极片1232相对正极片1231更靠近卷绕中心线，且负极片1232及隔离膜1233长出正极片1231的部分卷绕形成电极组件123的收尾卷绕段。也就是说，在电极组件123的起始卷绕段及中间卷绕段中，均包括负极片1232、隔离膜1233及正极片1231、但在收尾卷绕段，仅包括负极片1232及隔离膜1233。在这样的实施例中，起始卷绕段的负极片1232(如图4中包括由箭头j、箭头O、箭头p、箭头K、箭头l、箭头m、箭头r、箭头n所在位置的各段组合形成的负极片1232)的最内层的负极膜层，以及收尾卷绕段的负极片1232(如图4中包括由箭头a、箭头b、箭头c、箭头d、箭头e、箭头f、箭头g、箭头h所在位置的各段组合形成的负极片1232的最外层的负极膜层均具有非反应区12321。在该实施例中，负极片1232展开时，起始卷绕段中的非反应区12321以及收尾卷绕段的非反应区12321沿负极片1232的纵长方向X分布于负极片1232相对的两端，且分别位于负极片1232相对的两侧的负极膜层上。起始卷绕段中的非反应区12321以及收尾卷绕段的非反应区12321均设置有补锂层1234。
以下实施例，均以电极组件123为卷绕结构，且电极组件123按照图4中的设置方式为例进行说明。
具体地，起始卷绕段中最内层的负极片1232中最内层的负极膜层表面的非反应区12321，以及收尾卷绕段中最外层的负极片1232中最外层的负极膜层表面的非反应区12321均设置有补锂层1234。
在该实施例中，可以起始卷绕段的所有正极片1231与所有负极片1232中，位于最内层的负极片1232上的非反应区12321设有补锂层1234，和/或，收尾卷绕段的所有正极片1231与所有负极片1232中，位于最外层的负极片1232上的非反应区12321设有补锂层1234，这样，可以有效提升电极组件123的首次库伦效率、循环性能及存储性能。
在该实施例中，电极组件123的起始卷绕段及收尾卷绕段均有可能设置非反应区12321。非反应区12321位点越多越利于补锂层1234的分配，从而可根据需要选择设置补锂层1234的位置。
根据本申请的一些实施例，起始卷绕段及收尾卷绕段中上的每个非反应区12321均设有补锂层1234，设于起始卷绕段上的所有补锂层1234的补锂总容量为Q 1，设于收尾卷绕 段上的所有补锂层1234的补锂总容量为Q 2，Q Li＝Q 1+Q 2，且Q 1＞Q 2。
由于起始卷绕段相较于收尾卷绕段位于电极组件123的中心，则当起始卷绕段被电解液充分浸润后保液能力远高于收尾卷绕段。这样，更有利于补锂层1234中锂离子的扩散，以进一步改善电芯的首次库伦效率、循环以及存储性能。
根据本申请的一些实施例，所有补锂层1234的补锂总面积为S Li，每个负极片1232单侧的负极膜层中单位面积的容量为C 负，S Li满足条件：Q Li/120％C 负≤S Li≤Q Li/20％C 负。
负极片1232上的非反应区12321的电位高低与非反应区12321的补锂面积有直接关系。补锂面积越大，负极片1232上非反应区12321的电位降低程度越大，那么，整个负极片1232的电位也将降低。这样，负极片1232和与该负极片1232相邻设置的正极片1231之间的电位差也会更大。根据能量＝电位差X容量的公式，电位差越大，则二次电池12的能量也越大。因此，在该种设计下，二次电池12具有较高的能量密度。
根据本申请的一些实施例，S Li满足条件：Q Li/90％C 负≤S Li≤Q Li/50％C 负。
在该范围内，二次电池12内的补锂面积较为合适，利用率较高，可以有效提升二次电池12的首次库伦效率、循环性能及存储性能。
请一并参阅图5及图6，根据本申请的一些实施例，补锂层1234包括：多个第一补锂单元12341，沿所在的负极片1232的纵长方向X间隔设置；和/或多个第二补锂单元12342，沿所在的负极片1232的横向Y间隔设置。
其中，以电极组件123为叠片结构为例，负极片1232的纵长方向X即为其长度方向，负极片1232的横向Y即为其宽度方向。以电极组件123为卷绕结构为例，负极片1232的纵长方向X是指其展开时的长度方向，负极片1232的横向Y是指其展开时的宽度方向，在卷绕的过程中，负极片1232沿其纵长方向X进行卷绕。
其中，补锂层1234可以仅包括多个第一补锂单元12341，或者，也可以仅包括多个第二补锂单元12342，或者，也可以同时包括多个第一补锂单元12341及多个第二补锂单元12342。第一补锂单元12341与第二补锂单元12342之间可能相交设置，也可能间隔设置。
在该种实施例中，任意相邻的两个第一补锂单元12341之间，和/或任意相邻的两个第二补锂单元12342之间均存在间隙。间隙的设置，使得电解液可以充分浸润至非反应区12321，这样，补锂层1234可以快速嵌入至与其重叠的负极膜层并形成新的稳定的补锂层1234，新的稳定的补锂层1234可以缓慢的补充锂离子，从而有助于延长二次电池12的使用寿命。
根据本申请的一些实施例，每个第一补锂单元12341沿其所在的负极片1232的横向Y延伸至该负极片1232相对的两边缘。
其中，第一补锂单元12341可以为条状、杆状、长方形状等等。
在该种设计下，能够充分利用非反应区12321的空间设置第一补锂单元12341，以 使得第一补锂单元12341具有较大的长度，随之，第一补锂单元12341的补锂容量也增加，使得二次电池12具有较好的补锂效果。此外，每相邻的两个第一补锂单元12341之间形成的间隙还可保障电解液能够充分浸润。
根据本申请的一些实施例，每个第二补锂单元12342包括多个补锂部123421，每个补锂部123421均为块状，每个第二补锂单元12342的所有补锂部123421沿所在的负极片1232的纵长方向X间隔设置。
其中，第二补锂单元12342可以为方块状、圆形块状、三角形块状等等，具体结构在此处不做限定。
在该种实施例中，能够进一步保障电解液的充分浸润。
请一并参阅图7，根据本申请的一些实施例，补锂层1234被构造为沿其所在的负极片1232的纵长方向X连续延伸的层结构。
也就是说，补锂层1234为致密且连续的层结构。
这样，负极片1232上具有较大的补锂面积，则负极片1232和与该负极片1232相邻设置的正极片1231之间的电位差也会更大。根据能量＝电位差X容量的公式，电位差越大，则二次电池12的能量也越大，随之，二次电池12的循环性能及存储性能也可以随之提升。
请一并参阅图8，根据本申请的一些实施例，补锂层1234上开设有多个通孔12343。
具体地，通孔12343的排列方式可以为矩阵式排布，也可以为不规则排布，具体形式可以根据需求进行设置。
以补锂层1234为锂箔为例，设置有多个通孔12343的锂箔的制作过程如下：
第一步：生产出的锂箔按锂箔的补锂总面积S Li裁出需要的长度及宽度的锂箔；
第二步：用聚乙烯膜(PE膜)将锂箔沿其厚度方向布设的两个正反面完全包裹(防止造孔时锂箔粘在造孔设备上)
第三步：将聚乙烯膜包裹的好的锂箔匀速的通过辊压机，辊压机中的其中一个辊的表面设置短而密集的尖钉，按需求设置合适的辊缝，锂箔从辊缝中通过后即可造出多孔的锂箔。
补锂层1234为致密且连续的层结构时，在电极组件123卷绕成型后，将导致补锂层1234覆盖的非反应区12321无法被电解液完全浸润，这将导致补锂层1234上大量的锂会在较长时间内暴露在非反应区12321的表面，加速消耗电解液，加重二次电池12产气。
而通过设置多个通孔12343，可以增加负极片1232的孔隙率，以使得电解液可以充分浸润，从而有助于延长二次电池12的使用寿命。
根据本申请的一些实施例，补锂层1234的补锂面积为S 1，补锂层1234上所有通孔 12343的横截面积总和为S 2，S 2满足条件：5％S 1≤S 2≤50％S 1。
通孔12343的横街面积是指平行于通孔12343的开口所在的平面的截面积。所有通孔12343的横截面积总和是指所有通孔12343的横街面积之和。
所有通孔12343的横截面积总和越大，则电解液的浸润也更充分，则补锂层1234能够更快地嵌入至与其重合的负极膜层并形成稳定结构。当然，所有通孔12343的横截面积总和越大，也会导致补锂层1234的有效补锂面积减少。其中，补锂层1234的有效补锂面积是指：补锂层1234的补锂面积S 1与补锂层1234上所有通孔12343的横截面积总和S 2之差。
通过设置S 2满足条件：5％S 1≤S 2≤50％S 1，在能够满足补锂需求的同时，还使得电解液能够充分进行浸润，从而有助于进一步提升二次电池12的首次库伦效率、循环性能及存储性能。
根据本申请的一些实施例，S2满足条件：20％S1≤S2≤30％S1。
在该种实施例下，电解液具有较优的浸润及补锂效果。
下面，通过22个实施例及2个对比例来说明二次电池12的性能。
Figure PCTCN2022110842-appb-000001
Figure PCTCN2022110842-appb-000002
Figure PCTCN2022110842-appb-000003
有上述实施例与对比例结合可知，设有补锂层1234的负极片1232的首次库伦效率相较于未设置补锂层1234的负极片1232的首次库伦效率高，设有补锂层1234的负极片1232的容量保持率相较于未设置补锂层1234的负极片1232的容量保持率高。随着Q1及Q2的增大，负极片1232的首次库伦效率及容量保持率均提升。随着补锂层1234上所有通孔12343的横截面积总和占补锂层1234的补锂面积百分比的增大，负极片1232的首次库伦效率及容量保持率均提升。
第二方面，本申请还提供了一种电池10，其包括如上述任一项实施例所述的二次电池12。
第三方面，本申请提供了一种用电装置，包括如上述任一项实施例所述的电池10，电池10用于提供电能，或者包括任一项实施例所述的二次电池12，二次电池12用于提供电能。
根据本申请的一些实施例，本申请提供了一种二次电池12，二次电池12包括电极组件123，电极组件123包括至少一个正极片1231及至少一个负极片1232，至少一个负极片1232的负极膜层上具有非反应区12321，非反应区12321和与其所在的负极片1232相邻设置的正极片1231上的正极膜层不相对设置，且至少一个非反应区12321上设有补锂层1234；其中，二次电池12的总容量为Q，所有补锂层1234补锂的总容量为Q Li，Q Li满足条件：2％Q≤Q Li≤6％Q。
在这样的二次电池12中，不但可以提升二次电池12的首次库伦效率、循环性能及存储性能，同时，还具有较高的补锂层1234的利用率。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这都属于本申请的保护范围。

Claims (17)

  1. 一种二次电池，包括电极组件，电极组件包括：至少一个正极片及至少一个负极片，至少一个负极片的负极膜层上具有非反应区，非反应区和与其所在的负极片相邻设置的正极片上的正极膜层不相对设置，且至少一个非反应区上设有补锂层；
    其中，二次电池的总容量为Q，所有补锂层补锂的总容量为Q Li，Q Li满足条件：0.5％Q≤Q Li≤10％Q。
  2. 根据权利要求1所述的二次电池，其中，补锂层为锂金属单质层。
  3. 根据权利要求1所述的二次电池，其中，Q Li满足条件：2％Q≤Q Li≤6％Q。
  4. 根据权利要求1所述的二次电池，其中，电极组件包括隔离膜，电极组件被构造为由正极片、隔离膜及负极片层叠设置形成的叠片结构；
    在所有的正极片与所有的负极片中，最外层的负极片中最外层的负极膜层的表面形成非反应区，补锂层覆盖非反应区。
  5. 根据权利要求1所述的二次电池，其中，电极组件包括隔离膜，电极组件被构造为由正极片、隔离膜及负极片卷绕形成的卷绕结构；
    电极组件包括起始卷绕段及收尾卷绕段，起始卷绕段的所有正极片与所有负极片中，最内层的负极片中最内层的负极膜层的表面，和/或收尾卷绕段的所有正极片与所有负极片中，最外层的负极片中最外层的负极膜层的表面形成有非反应区，起始卷绕段及收尾卷绕段中至少一者上的非反应区设有补锂层。
  6. 根据权利要求5所述的二次电池，其中，起始卷绕段及收尾卷绕段中的每个非反应区均设有补锂层，设于起始卷绕段上的所有补锂层的补锂总容量为Q 1，设于收尾卷绕段上的所有补锂层的补锂总容量为Q 2，Q Li＝Q 1+Q 2，且Q 1＞Q 2。
  7. 根据权利要求1所述的二次电池，其中，所有补锂层的补锂总面积为S Li，每个负极片单侧的负极膜层中单位面积的容量为C 负，S Li满足条件：
    Q Li/120％C 负≤S Li≤Q Li/20％C 负。
  8. 根据权利要求7所述的二次电池，其中，S Li满足条件：
    Q Li/90％C 负≤S Li≤Q Li/50％C 负。
  9. 根据权利要求1所述的二次电池，其中，补锂层包括：
    多个第一补锂单元，沿所在的负极片的纵长方向间隔设置；和/或
    多个第二补锂单元，沿所在的负极片的横向间隔设置。
  10. 根据权利要求9所述的二次电池，其中，每个第一补锂单元沿所在的负极片的横向延伸至该负极片相对的两边缘。
  11. 根据权利要求10所述的二次电池，其中，每个第二补锂单元包括多个补锂部，每 个补锂部均为块状，每个第二补锂单元的所有补锂部沿所在的负极片的纵长方向间隔设置。
  12. 根据权利要求1所述的二次电池，其中，补锂层被构造为沿其所在的负极片的纵长方向连续延伸的层结构。
  13. 根据权利要求12所述的二次电池，其中，补锂层上开设有多个通孔。
  14. 根据权利要求13所述的二次电池，其中，补锂层的补锂面积为S 1，补锂层上所有所述通孔的横截面积总和为S 2，S 2满足条件：5％S 1≤S 2≤50％S 1。
  15. 根据权利要求14所述的二次电池，其中，S 2满足条件：20％S 1≤S 2≤30％S 1。
  16. 一种电池，其中，包括如上述权利要求1至15任一项所述的二次电池。
  17. 一种用电装置，其中，包括如上述权利要求16所述的电池，所述电池用于提供电能；或者，
    包括如上述权利要求1至15任一项所述的二次电池，二次电池用于提供电能。
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1770545A (zh) * 2004-11-02 2006-05-10 三洋电机株式会社 锂二次电池及其制造方法
JP2010287641A (ja) * 2009-06-10 2010-12-24 Nec Tokin Corp 蓄電デバイス
CN107851523A (zh) * 2015-07-10 2018-03-27 太阳诱电株式会社 电化学器件
CN111312987A (zh) * 2018-12-12 2020-06-19 宁德时代新能源科技股份有限公司 卷绕式电芯、锂离子二次电池及负极极片
CN111384405A (zh) * 2018-12-28 2020-07-07 宁德时代新能源科技股份有限公司 电极组件以及锂离子电池
CN114597383A (zh) * 2020-12-04 2022-06-07 比亚迪股份有限公司 一种可控设计长寿命的锂离子电池及动力车辆

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1770545A (zh) * 2004-11-02 2006-05-10 三洋电机株式会社 锂二次电池及其制造方法
JP2010287641A (ja) * 2009-06-10 2010-12-24 Nec Tokin Corp 蓄電デバイス
CN107851523A (zh) * 2015-07-10 2018-03-27 太阳诱电株式会社 电化学器件
CN111312987A (zh) * 2018-12-12 2020-06-19 宁德时代新能源科技股份有限公司 卷绕式电芯、锂离子二次电池及负极极片
CN111384405A (zh) * 2018-12-28 2020-07-07 宁德时代新能源科技股份有限公司 电极组件以及锂离子电池
CN114597383A (zh) * 2020-12-04 2022-06-07 比亚迪股份有限公司 一种可控设计长寿命的锂离子电池及动力车辆

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