WO2021027782A1

WO2021027782A1 - Lithium-supplementing negative electrode sheet, preparation method therefor, and lithium ion battery, battery module, battery pack and device related thereto

Info

Publication number: WO2021027782A1
Application number: PCT/CN2020/108233
Authority: WO
Inventors: 谢斌; 陈仕通; 龚志杰
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2019-08-05
Filing date: 2020-08-10
Publication date: 2021-02-18
Also published as: CN112331928A

Abstract

The present application provides a lithium-supplementing negative electrode sheet, a preparation method therefor, and a lithium ion battery, a battery module, a battery pack and a device related thereto. The lithium-supplementing negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector. A plurality of lithium-supplementing modules are arranged in an array on a surface of the negative electrode active material layer away from the negative electrode current collector. After the electrode is formed into a sheet, the ratio S₁/S₀ of the sum S_/S of the projected areas of lithium oxide layers remained in the plurality of lithium-supplementing modules on the negative electrode active material layer to the area S₀ of the negative electrode active material layer is 30% to 99%.

Description

补锂负极极片、其制备方法、及其相关的锂离子电池、电池模块、电池包和装置Lithium supplement negative pole piece, preparation method thereof, and related lithium ion battery, battery module, battery pack and device

相关申请的交叉引用Cross references to related applications

本申请要求享有于2019年08月13日提交的名称为“一种负极补锂极片及锂离子电池”的中国专利申请201910744596.9的优先权，该申请的全部内容通过引用并入本文中。This application claims the priority of the Chinese patent application 201910744596.9 entitled "A negative electrode supplementary lithium pole piece and lithium ion battery" filed on August 13, 2019. The entire content of the application is incorporated herein by reference.

技术领域Technical field

本申请涉及电池领域，具体涉及一种补锂负极极片、其制备方法、及其相关的锂离子电池、电池模块、电池包和装置。This application relates to the field of batteries, in particular to a lithium-replenishing negative electrode sheet, a preparation method thereof, and related lithium-ion batteries, battery modules, battery packs and devices.

背景技术Background technique

随着新能源汽车的普及，对锂离子动力电池的需求也日益增加；同时，对动力电池性能的要求也越来越高，不但要求电池既要有快速充电的能力，还要有较高的能量密度、较好的长循环性能和稳定性。With the popularity of new energy vehicles, the demand for lithium-ion power batteries is also increasing. At the same time, the requirements for power battery performance are also getting higher and higher. Not only are batteries required to have fast charging capabilities, but also higher Energy density, good long-cycle performance and stability.

预补锂技术不仅可以弥补阳极的首效损失，还能提供额外的锂源，有助于提升锂离子电池的能量密度及循环性能。但是，极片补锂技术还有待于进一步改进和优化。The pre-filled lithium technology can not only make up for the first effect loss of the anode, but also provide an additional lithium source, which helps to improve the energy density and cycle performance of lithium-ion batteries. However, the pole piece lithium supplement technology needs to be further improved and optimized.

发明内容Summary of the invention

本申请的第一方面提供了一种补锂负极极片，其包括负极集流体以及设置在所述负极集流体至少一个表面上的负极活性材料层；所述负极活性材料层远离所述负极集流体的表面上呈阵列排布有若干补锂膜块；所述补锂负极极片化成后，若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀为30％～99％。 The first aspect of the present application provides a lithium-supplemented negative electrode sheet, which includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector; the negative electrode active material layer is away from the negative electrode collector A number of lithium supplementary film blocks are arranged in an array on the surface of the fluid; after the lithium supplementary negative electrode is formed, the sum of the projected areas of the lithium supplementary oxide layer remaining on the negative electrode active material layer S ₁ and The ratio S ₁ /S ₀ of the area S ₀ of the negative electrode active material layer is 30% to 99%.

本申请实施方式所提供的补锂负极极片中，呈阵列排布的若干补锂膜块非连续地分布于负极极片的活性材料层上，因而，在极片表面形成了间隔排布的补锂区和非补锂区。一方面，非补锂区提供了长程有序的通风通道，在补锂工艺过程中，可带走补锂材料与极片之间的反应热量，减小安全风险。另一方面，非补锂区的存在也有助于极片表面锂层的扩散，给锂离子的嵌入提供通道，使其在电解液中可以更快地浸润到极片表面。再一方面，补锂极片浸润电解液后，补锂区残留的补锂氧化层对锂离子传输有一定的不利影响，非补锂区的存在有助于减弱上述影响。In the lithium-supplementing negative pole piece provided by the embodiment of the present application, several lithium-supplementing film blocks arranged in an array are discontinuously distributed on the active material layer of the negative pole piece, thus forming spaced-apart arrays on the surface of the pole piece. Lithium supplementation area and non-lithium supplementation area. On the one hand, the non-lithium supplement area provides a long-distance and orderly ventilation channel. During the lithium supplement process, the heat of reaction between the lithium supplement material and the pole piece can be taken away, reducing safety risks. On the other hand, the existence of the non-replenishing lithium area also helps the diffusion of the lithium layer on the surface of the pole piece, and provides a channel for the insertion of lithium ions, so that it can infiltrate the surface of the pole piece faster in the electrolyte. On the other hand, after the lithium supplement electrode is soaked in the electrolyte, the residual lithium supplement oxide layer in the lithium supplement area has a certain adverse effect on lithium ion transmission, and the existence of the non-lithium supplement area helps to reduce the above influence.

呈阵列排布的若干补锂膜块本身具备一定高度，可近似地看作为凸点，从而采用该负极极片的卷绕式电芯，能在拐角处形成一定间隙，在电池循环过程中为极片的膨胀提供可使用的空间。一方面，可避免缓解极片膨胀引起的极片断裂、甚至刺穿隔离膜的安全风险。另一方面，也可保证拐角处的空气流通，利于散热，防止因为空气流通不畅导致卷绕后的补锂电芯拐角发黑的问题，从而提高补锂电池的锂利用率，最终改善电池的性能。Several lithium replenishment film blocks arranged in an array have a certain height, which can be regarded as bumps, so that the wound cell with the negative pole piece can form a certain gap at the corner, which is The expansion of the pole piece provides usable space. On the one hand, it can avoid alleviating the safety risk of pole piece fracture caused by pole piece expansion and even piercing the isolation membrane. On the other hand, it can also ensure the air circulation at the corners, which is conducive to heat dissipation, and prevents the corners of the wound lithium battery cell from turning black due to poor air circulation, thereby increasing the lithium utilization rate of the lithium battery and ultimately improving the battery performance.

通过S ₁/S ₀比值的合理控制，确保了上述补锂效果的实现。当S ₁/S ₀在本申请所限定范围内时，活性物质与锂层反应热可控，不会因补锂区覆盖面积过大导致锂层与活性物质接触面积增加导致发热不可控；也不会因非补锂区面积过大导致化成界面出现未嵌入的锂层。非补锂区可提供大小合适的通道供空气流通，将活性物质与锂层发生反应的热量带走，降低极片温度；同时能保证锂层在活性材料层表面有效扩散，降低锂层无法完全嵌入活性物质层的风险。 The reasonable control of the ratio of S ₁ /S ₀ ensures the realization of the above lithium supplement effect. When S ₁ /S _{0 is} within the range defined in this application, the reaction heat of the active material and the lithium layer is controllable, and the area of contact between the lithium layer and the active material will not increase due to the excessive coverage of the lithium replenishment area, which may lead to uncontrollable heat generation; The excessively large area of the non-supplemented lithium region will not cause an unembedded lithium layer at the formation interface. The non-supplemented lithium zone can provide a channel of appropriate size for air circulation to take away the heat from the reaction between the active material and the lithium layer and reduce the temperature of the pole piece; at the same time, it can ensure the effective diffusion of the lithium layer on the surface of the active material layer, reducing the incompleteness of the lithium layer Risk of embedding in the active material layer.

在上述任意实施方式中，S ₁/S ₀为40％～98％；可选的，S ₁/S ₀为50％～78％。当S ₁/S ₀在所给范围内时，能保证补锂膜块在活性材料层表面的有效扩散和降低极片嵌锂反应过程中的温度，同时进一步提高电池的循环性能。 In any of the foregoing embodiments, S ₁ /S ₀ is 40% to 98%; optionally, S ₁ /S ₀ is 50% to 78%. When S ₁ /S _{0 is} within the given range, it can ensure the effective diffusion of the lithium supplement film on the surface of the active material layer and reduce the temperature during the lithium insertion reaction of the pole piece, while further improving the cycle performance of the battery.

在上述任意实施方式中，所述负极活性材料层中的负极活性物质可包含硅基材料，所述补锂膜块的厚度可以为0.5μm～30μm，可选的为0.5μm～15μm，可选的为1μm～4μm。补锂负极极片满足上述条件，能进一步改善电池的安全性能和循环性能。In any of the foregoing embodiments, the negative active material in the negative active material layer may include a silicon-based material, and the thickness of the lithium supplement film block may be 0.5 μm-30 μm, optionally 0.5 μm-15 μm, optionally Is 1μm～4μm. The lithium supplementary negative pole piece meets the above conditions, and can further improve the safety performance and cycle performance of the battery.

在上述任意实施方式中，所述补锂膜块的形状可选自长方形、正方形、圆形或菱形，例如选自长方形、正方形或菱形，再例如选自正方形。补锂膜块具有合适的形状，能获得更好的补锂效果，进一步提升电池的循环性能。In any of the foregoing embodiments, the shape of the lithium supplement film block can be selected from rectangle, square, circle, or rhombus, for example, from rectangle, square, or rhombus, and for example, from square. The lithium replenishment membrane block has a suitable shape, can obtain a better lithium replenishment effect, and further improves the cycle performance of the battery.

在上述任意实施方式中，可选的，所述补锂膜块为正方形补锂膜块，且所述正方形补锂膜块的边长为20μm～5000μm，可选的为30μm～1500μm，可选的为30μm～1000μm。补锂膜块为正方形且其边长在上述范围内，使得锂层在活性材料层表面易于扩散，活性物质与锂层的反应热可控，化成后的锂层厚度适中，可改善散热及电解液浸润性能，可获得较佳的补锂效果，进一步改善电池的循环性能。In any of the foregoing embodiments, optionally, the lithium supplementary membrane block is a square lithium supplementary membrane block, and the side length of the square lithium supplementary membrane block is 20 μm to 5000 μm, optionally 30 μm to 1500 μm, optionally It is 30μm～1000μm. The lithium replenishment film block is square and its side length is within the above range, so that the lithium layer is easy to diffuse on the surface of the active material layer, the reaction heat of the active material and the lithium layer is controllable, and the thickness of the formed lithium layer is moderate, which can improve heat dissipation and electrolysis The liquid wettability can obtain a better effect of replenishing lithium and further improve the cycle performance of the battery.

在一些实施方式中，相邻两个所述正方形补锂膜块之间的距离为10μm～2000μm，可选的为30μm～1500μm，可选的为30μm～1000μm。补锂膜块为正方形且彼此间的距离在上述范围内，使得非补锂区所提供的导热通道充足，锂层与活性材料层浸润效果良好，保证锂层浸润效果，有利于降低电芯内阻，并最终改善电池的循环性能。In some embodiments, the distance between two adjacent square lithium supplementary membrane blocks is 10 μm to 2000 μm, optionally 30 μm to 1500 μm, and optionally 30 μm to 1000 μm. The lithium replenishment film blocks are square and the distance between each other is within the above range, so that the non-lithium replenishment area provides sufficient heat conduction channels, the lithium layer and the active material layer have a good wetting effect, and the lithium layer wetting effect is guaranteed, which is beneficial to reduce the cell Resistance, and ultimately improve the cycle performance of the battery.

在上述任意实施方式中，可选的，所述补锂膜块为圆形补锂膜块，所述圆形补锂膜块的半径为7μm～1000μm，可选的8μm～700μm，可选的为10μm～500μm，可选的为100μm～500μm。补锂膜块为圆形且其半径在上述范围内，能改善锂层在活性材料层表面的扩散效果，降低极片嵌锂反应温度，化成后的锂层厚度适中，进一步改善电池的循环性能。In any of the foregoing embodiments, optionally, the lithium supplementary membrane block is a circular lithium supplementary membrane block, and the radius of the circular lithium supplementary membrane block is 7 μm to 1000 μm, optionally 8 μm to 700 μm, and optional It is 10μm～500μm, and can be 100μm～500μm. The lithium replenishment film block is circular and its radius is within the above range, which can improve the diffusion effect of the lithium layer on the surface of the active material layer, reduce the reaction temperature of lithium insertion of the pole piece, and the thickness of the formed lithium layer is moderate, which further improves the cycle performance of the battery .

在一些实施方式中，相邻两个所述圆形补锂膜块之间的最短距离为10μm～1000μm，可选的为10μm～500μm，可选的为100μm～500μm。补锂膜块为圆形且彼此间的距离在上述范围内，使得非补锂区提供足够的导热通道，锂层的补锂效果良好，并有利于降低电芯内阻，从而改善电池的安全性能和循环性能。In some embodiments, the shortest distance between two adjacent circular lithium supplementary membrane blocks is 10 μm to 1000 μm, optionally 10 μm to 500 μm, and optionally 100 μm to 500 μm. The lithium replenishment film blocks are circular and the distance between each other is within the above range, so that the non-replenishment area provides sufficient heat conduction channels, the lithium replenishment effect of the lithium layer is good, and it is helpful to reduce the internal resistance of the battery cell, thereby improving the safety of the battery Performance and cycle performance.

在上述任意实施方式中，所述补锂膜块的原料可选自锂粉、锂锭和锂片中的一种或多种。In any of the foregoing embodiments, the raw material of the lithium supplement film block can be selected from one or more of lithium powder, lithium ingot and lithium flake.

在上述任意实施方式中，可选的，所述补锂膜块的原料选自锂粉，其中，所述补锂膜块为由锂粉浆料涂布，并经干燥而成的，所述锂粉浆料包含锂粉和有机溶剂。In any of the foregoing embodiments, optionally, the raw material of the lithium supplement film block is selected from lithium powder, wherein the lithium supplement film block is formed by coating with a lithium powder slurry and drying, the The lithium powder slurry contains lithium powder and an organic solvent.

在上述任意实施方式中，所述补锂氧化层可包括选自单质锂、氧化锂、氮化锂、氟化锂、氢氧化锂、碳酸锂、碳化锂、锂硅合金中的一种或多种。In any of the foregoing embodiments, the lithium-supplementing oxide layer may include one or more selected from elemental lithium, lithium oxide, lithium nitride, lithium fluoride, lithium hydroxide, lithium carbonate, lithium carbide, and lithium silicon alloy. Kind.

本申请第二方面提供一种补锂负极极片的制备方法，其包括以下步骤：The second aspect of the present application provides a method for preparing a lithium-supplemented negative pole piece, which includes the following steps:

(a)提供待补锂的负极极片，所述待补锂的负极极片包括负极集流体以及设置在所述负极集流体至少一个表面上的负极活性材料层；(a) Providing a negative pole piece for lithium to be supplemented, which comprises a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector;

(b)在所述负极活性材料层远离所述负极集流体的表面上形成呈阵列排布的若干补锂膜块，得到补锂负极极片；(b) forming a plurality of lithium supplement film blocks arranged in an array on the surface of the negative electrode active material layer away from the negative electrode current collector to obtain a lithium supplement negative pole piece;

其中，所述补锂负极极片化成后，若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀为30％～99％。 Wherein, after the formation of the lithium-supplementing negative electrode, the sum of the projected areas of the lithium-supplementing oxide layers remaining on the negative electrode active material layer S ₁ and the area S ₀ of the negative electrode active material layer S ₁ / S ₀ is 30% to 99%.

本申请提供的制备方法能得到本申请所述的补锂负极极片，因而能获得相同或类似的有益效果。The preparation method provided in the present application can obtain the lithium-supplemented negative pole piece described in the present application, and thus can obtain the same or similar beneficial effects.

在上述任意实施方式中，步骤(b)包括：将锂粉分散于有机溶剂中，得到补锂浆料；所述负极活性材料层的远离所述负极集流体的表面区分为呈阵列排布的若干补锂区域，将所述补锂浆料涂布于所述若干补锂区域，经干燥，形成阵列排布的若干补锂膜块。In any of the foregoing embodiments, step (b) includes: dispersing lithium powder in an organic solvent to obtain a lithium supplement slurry; the surface of the negative electrode active material layer away from the negative electrode current collector is divided into arrays. A plurality of lithium supplement areas, the lithium supplement slurry is coated on the plurality of lithium supplement regions, and dried to form a plurality of lithium supplement film blocks arranged in an array.

在上述任意实施方式中，通过丝网印刷工艺将所述补锂浆料涂布于所述若干补锂区域。In any of the foregoing embodiments, the lithium supplementation paste is applied to the plurality of lithium supplementation regions through a screen printing process.

本申请的第三方面提供一种锂离子电池，其包括正极极片、负极极片、间隔于所述正极极片和所述负极极片之间的隔离膜、电解液，所述负极极片采用本申请第一方面所提供的补锂负极极片或根据本申请第二方面的制备方法得到的补锂负极极片。The third aspect of the present application provides a lithium ion battery, which includes a positive pole piece, a negative pole piece, a separator spaced between the positive pole piece and the negative pole piece, an electrolyte, and the negative pole piece The lithium-supplemented negative pole piece provided in the first aspect of the application or the lithium-supplemented negative pole piece obtained according to the preparation method of the second aspect of the application is used.

本申请的锂离子电池采用本申请所述的补锂负极极片，因而能获得相同或类似的有益效果。The lithium ion battery of the present application adopts the lithium supplementary negative pole piece described in the present application, and thus can obtain the same or similar beneficial effects.

在一些实施方式中，正极极片、负极极片和隔离膜组成卷绕式电芯。所述卷绕式电芯化成后的拐角间隙为0.1μm～50μm，可选的为3μm～30μm，可选的为1.5μm～6μm。采用本申请的补锂负极极片的卷绕式电芯，能进一步改善电池的安全性能和循环性能。当卷绕式电芯的拐角间隙在上述范围时，能更好地发挥上述效果，使电池获得更高的循环性能，还有利于提高电池的能量密度。In some embodiments, the positive pole piece, the negative pole piece and the separator constitute a wound cell. The corner gap after formation of the wound cell is 0.1 μm-50 μm, optionally 3 μm-30 μm, and optionally 1.5 μm-6 μm. The use of the wound battery cell of the lithium-supplemented negative pole piece of the present application can further improve the safety performance and cycle performance of the battery. When the corner gap of the wound cell is in the above range, the above effect can be better exerted, the battery can obtain higher cycle performance, and it is also beneficial to increase the energy density of the battery.

在一些实施方式中，正极极片、负极极片和隔离膜组成卷绕式电芯。所述卷绕式电芯化成后，所述负极极片与所述隔离膜之间的间隙为0.1μm～50μm，可选的为3μm～30μm，可选的为1.5μm～6μm。当化成后的卷绕式电芯中负极极片与隔离膜之间的间隙在上述范围时，采用其的电池能获得更好的循环性能和安全性能，同时还可获得较高的能量密度。In some embodiments, the positive pole piece, the negative pole piece and the separator constitute a wound cell. After the winding cell is formed, the gap between the negative pole piece and the isolation membrane is 0.1 μm-50 μm, optionally 3 μm-30 μm, and optionally 1.5 μm-6 μm. When the gap between the negative pole piece and the separator in the wound cell after formation is in the above range, the battery using the same can obtain better cycle performance and safety performance, and at the same time, higher energy density can be obtained.

本申请的第四方面提供一种电池模块，其包括本申请第三方面所述的锂离子电池。A fourth aspect of the present application provides a battery module, which includes the lithium ion battery described in the third aspect of the present application.

本申请第五方面提供一种电池包，其包括本申请第四方面所述的电池模块。A fifth aspect of the present application provides a battery pack, which includes the battery module described in the fourth aspect of the present application.

本申请第六方面提供一种装置，其包括本申请第三方面所述的锂离子电池、本申请第四方面所述的电池模块、或根据本申请第五方面所述的电池包。A sixth aspect of the present application provides a device, which includes the lithium ion battery described in the third aspect of the present application, the battery module described in the fourth aspect of the present application, or the battery pack according to the fifth aspect of the present application.

本申请的电池模块、电池包和装置包括本申请所述锂离子电池，因而至少具有与所述锂离子电池相同或类似的技术效果。The battery module, battery pack, and device of the present application include the lithium ion battery described in the present application, and therefore have at least the same or similar technical effects as the lithium ion battery.

附图说明Description of the drawings

图1为补锂负极极片的一实施方式的示意图。Fig. 1 is a schematic diagram of an embodiment of a lithium-supplemented negative pole piece.

图2为图1的补锂负极极片的侧视示意图。Fig. 2 is a schematic side view of the lithium supplementary negative pole piece of Fig. 1.

图3为图1的补锂负极极片化成后的侧视示意图。3 is a schematic side view of the lithium-supplemented negative electrode of FIG. 1 after formation.

图4为电芯的一实施方式的局部示意图。Fig. 4 is a partial schematic diagram of an embodiment of a battery cell.

图5是锂离子电池的一实施方式的示意图。FIG. 5 is a schematic diagram of an embodiment of a lithium ion battery.

图6是图5的分解图。Fig. 6 is an exploded view of Fig. 5.

图7是电池模块的一实施方式的示意图。Fig. 7 is a schematic diagram of an embodiment of a battery module.

图8是电池包的一实施方式的示意图。Fig. 8 is a schematic diagram of an embodiment of a battery pack.

图9是图8的分解图。Fig. 9 is an exploded view of Fig. 8.

图10是锂离子电池用作电源的装置的一实施方式的示意图。FIG. 10 is a schematic diagram of an embodiment of a device in which a lithium ion battery is used as a power source.

附图未按照实际比例绘制。并且，为了清晰，可能夸大或缩小了部分结构的尺寸。The drawings are not drawn to actual scale. And, for clarity, the size of some structures may be exaggerated or reduced.

具体实施方式detailed description

下面详细说明根据本申请的锂离子电池。The lithium ion battery according to the present application will be described in detail below.

本申请的第一方面所提供的补锂负极极片，包括负极集流体以及设置在所述负极集流体至少一个表面上的负极活性材料层；所述负极活性材料层远离所述负极集流体的表面上呈阵列排布有若干补锂膜块；所述极片化成后，若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀为30％～99％。 The lithium-supplemented negative pole piece provided in the first aspect of the present application includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector; the negative electrode active material layer is away from the negative electrode current collector There are several lithium supplement film blocks arranged in an array on the surface; after the pole pieces are formed, the sum of the projected areas of the lithium supplement oxide layers remaining on the negative electrode active material layer S ₁ and the negative electrode active material layer The ratio S ₁ /S ₀ of the area S ₀ is 30% to 99%.

极片化成是指采用所述补锂负极极片的电池注入电解液后进行首次充放电。此处的补锂负极极片是尚未经过电解液浸润的负极极片。在化成过程中，补锂膜块对负极活性材料层进行预嵌锂，使补锂膜块中的金属锂预嵌入负极活性物质中。极片化成的充放电倍率例如是1C。作为示例，将电池以1C倍率电流充电至上限截止电压，再以1C倍率电流放电至下限截止电压。其中上限截止电压和下限截止电压是电池自身的特性。充放电倍率＝充放电电流/额定容量。即，1C是将电池的额定容量(也可称标称容量)用1小时放完的电流强度。例如，电池的额定容量为70Ah，1C倍率就是用70A的电流对电池进行充放电。电池充放电可采用新威移动电源成品专用测试仪(6V4A)进行。The pole piece formation refers to the first charge and discharge of the battery using the lithium supplementary negative pole piece after injecting electrolyte. The lithium-supplementing negative pole piece here is a negative pole piece that has not been infiltrated by the electrolyte. In the formation process, the lithium-supplementing membrane block pre-inserts lithium into the negative electrode active material layer, so that the metal lithium in the lithium-supplementing membrane block is pre-inserted into the negative electrode active material. The charge-discharge rate of the polar piece formation is, for example, 1C. As an example, the battery is charged to the upper cut-off voltage with a current of 1C, and then discharged to the lower cut-off voltage with a current of 1C. The upper limit cut-off voltage and the lower limit cut-off voltage are the characteristics of the battery itself. Charge and discharge rate = charge and discharge current/rated capacity. That is, 1C is the current intensity when the battery's rated capacity (or nominal capacity) is discharged in 1 hour. For example, the rated capacity of the battery is 70Ah, and the 1C rate is to charge and discharge the battery with a current of 70A. The battery charging and discharging can be carried out with the special tester (6V4A) for the finished product of Xinwei mobile power supply.

在本申请中，S ₁/S ₀的示例性测试方法如下：极片化成后，拆解电池，裁取补锂负极极片样品；分别测量若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁、负极活性材料层的面积S ₀，计算比值S ₁/S ₀。其中，补锂氧化层的面积可采用本领域已知的方法进行测定，例如采用SEM(例如蔡司SIGMA 500高分辨率场发射扫描电镜)扫描测试。极片样品的面积越大，测试结果精度越高。可选的，极片样品的面积为其中面积最小的补锂区面积的20倍，所得结果误差很小。极片样品的形状例如是长方形。为了测试结果更加精确，可以取多个(例如5个)极片样品分别测试S ₁/S ₀，取其平均值作为该补锂负极极片的S ₁/S ₀值。 In this application, the exemplary test method of S ₁ /S ₀ is as follows: after the pole pieces are formed, the battery is disassembled, and the samples of the lithium supplement negative pole piece are cut out; respectively, the residual lithium supplement oxide layer of several lithium supplement film blocks is measured on the negative electrode. The sum S ₁ of the projected area on the active material layer and the area S _{0 of the} negative active material layer are calculated as the ratio S ₁ /S ₀ . Wherein, the area of the lithium-supplemented oxide layer can be measured by a method known in the art, for example, a SEM (such as a Zeiss SIGMA 500 high-resolution field emission scanning electron microscope) scanning test. The larger the area of the pole piece sample, the higher the accuracy of the test result. Optionally, the area of the pole piece sample is 20 times the area of the lithium supplementation area with the smallest area, and the error of the result obtained is small. The shape of the pole piece sample is, for example, a rectangle. In order to make the test result more accurate, multiple (for example, 5) pole piece samples can be taken to test S ₁ /S _{0 respectively} , and the average value thereof is taken as the S ₁ /S ₀ value of the lithium supplement negative pole piece.

在本申请实施方式所提供的补锂负极极片中，呈阵列排布的若干补锂膜块非连续地分布于负极活性材料层上(即形成覆设在负极活性材料层表面的锂层)，因而，在极片表面形成了间隔排布的补锂区和非补锂区。一方面，非补锂区提供了长程有序的通风通道，在补锂工艺过程中，可带走补锂材料与极片之间的反应热量，减小安全风险。另一方面，非补锂区的存在也有助于极片表面锂层的扩散，给锂离子的嵌入提供通道，使其在电解液中可以更快地浸润到极片表面。再一方面，补锂极片浸润电解液后，补锂区残留的补锂氧化层对锂离子传输有一定的不利影响，非补锂区的存在也有助于消除上述影响，从而提高电池倍率性能。In the lithium-supplementing negative pole piece provided by the embodiment of the present application, several lithium-supplementing membrane blocks arranged in an array are discontinuously distributed on the negative electrode active material layer (that is, forming a lithium layer covering the surface of the negative electrode active material layer) As a result, lithium-supplemented areas and non-lithium-supplemented areas are formed on the surface of the pole pieces. On the one hand, the non-lithium supplement area provides a long-distance and orderly ventilation channel. During the lithium supplement process, the heat of reaction between the lithium supplement material and the pole piece can be taken away, reducing safety risks. On the other hand, the existence of the non-replenishing lithium area also helps the diffusion of the lithium layer on the surface of the pole piece, and provides a channel for the insertion of lithium ions, so that it can infiltrate the surface of the pole piece faster in the electrolyte. On the other hand, after the lithium supplement pole piece is soaked in the electrolyte, the residual lithium supplement oxide layer in the lithium supplement area has a certain adverse effect on the lithium ion transmission. The existence of the non-lithium supplement area also helps to eliminate the above influence, thereby improving the battery rate performance .

呈阵列排布的若干补锂膜块本身具备一定高度，可近似地看作为凸点，从而采用该负极极片的卷绕式电芯，能在拐角处形成一定间隙，在电池循环过程中对极片的膨胀提供可使用的供膨胀空间。一方面，可避免缓解极片膨胀引起的极片断裂、甚至刺穿隔离膜的安全风险。另一方面，也可保证拐角处的空气流通，利于散热，防止因为空气流通不畅导致卷绕后的补锂电芯拐角发黑的问题，从而提高补锂电池的锂利用率，最终改善电池的性能。Several lithium supplementary membrane blocks arranged in an array have a certain height, which can be regarded as bumps, so that the wound cell of the negative pole piece can form a certain gap at the corner, and it can be used in the battery cycle. The expansion of the pole pieces provides usable space for expansion. On the one hand, it can avoid alleviating the safety risk of pole piece fracture caused by pole piece expansion and even piercing the isolation membrane. On the other hand, it can also ensure the air circulation at the corners, which is conducive to heat dissipation, and prevents the corners of the wound lithium battery cell from turning black due to poor air circulation, thereby increasing the lithium utilization rate of the lithium battery and ultimately improving the battery performance.

发明人经锐意研究发现，通过S ₁/S ₀比值的合理控制，确保了上述补锂效果的实现。当S ₁/S ₀在本申请限定范围内时，活性物质与锂层反应热可控，不会因补锂膜块覆盖面积S ₁过大导致锂层与活性物质接触面积增加导致发热不可控；也不会因非补锂膜块面积过大导致化成界面出现未嵌入的锂层。非补锂区可提供大小适当的通道供空气流通，将活性物质与锂层发生反应的热量带走，降低极片温度；同时可保证锂层在活性材料层表面有效扩散，降低锂层无法完全嵌入活性物质层的风险。 After intensive research, the inventor found that reasonable control of the ratio of S ₁ /S _{0 can} ensure the realization of the aforementioned lithium supplement effect. When S ₁ /S _{0 is} within the scope of this application, the reaction heat of the active material and the lithium layer is controllable, and the contact area between the lithium layer and the active material will not increase due to the excessively large coverage area S ₁ of the lithium replenishing film block, resulting in uncontrollable heating ; Nor will there be an unembedded lithium layer at the formation interface due to the large area of the non-compensated lithium film block. The non-supplemented lithium area can provide a channel of appropriate size for air circulation to take away the heat from the reaction between the active material and the lithium layer and reduce the temperature of the pole piece; at the same time, it can ensure the effective diffusion of the lithium layer on the surface of the active material layer and reduce the incompleteness of the lithium layer Risk of embedding in the active material layer.

在一些实施方式中，可选的，S ₁/S ₀为40％～98％，44％～95％，50％～78％，或56％～73％等。当S ₁/S ₀在所给范围内时，能保证补锂膜块在活性材料层表面的有效扩散和降低极片嵌锂反应过程中的温度，同时进一步提高电池的循环性能。 In some embodiments, optionally, S ₁ /S ₀ is 40% to 98%, 44% to 95%, 50% to 78%, or 56% to 73%. When S ₁ /S _{0 is} within the given range, it can ensure the effective diffusion of the lithium supplement film on the surface of the active material layer and reduce the temperature during the lithium insertion reaction of the pole piece, while further improving the cycle performance of the battery.

在一些实施方式中，可选的，所述负极活性材料层中的负极活性物质包含硅基材料，所述补锂膜块的厚度为0.5μm～30μm。可选的，所述补锂膜块的厚度为0.5μm～15μm。可选的，所述补锂膜块的厚度为1μm～4μm。补锂负极极片满足上述条件时，锂层与活性物质层压实程度适中，接触效果较佳，电解液浸润效果较好，还能在电芯拐角处或电芯各处的负极极片与隔离膜之间形成一定的间隙，给极片在循环过程中的膨胀预留膨胀空间，从而更好地改善电芯的安全性能和循环性能。In some embodiments, optionally, the negative electrode active material in the negative electrode active material layer includes a silicon-based material, and the thickness of the lithium supplement film block is 0.5 μm-30 μm. Optionally, the thickness of the lithium supplement film block is 0.5 μm-15 μm. Optionally, the thickness of the lithium supplement film block is 1 μm-4 μm. When the lithium-supplementing negative pole piece meets the above conditions, the degree of compaction between the lithium layer and the active material is moderate, the contact effect is better, the electrolyte infiltration effect is better, and the negative pole piece at the corner of the cell or around the cell A certain gap is formed between the isolation membranes to reserve expansion space for the expansion of the pole pieces during the cycle, so as to better improve the safety performance and cycle performance of the battery.

在一些实施方式中，可选的，所述补锂膜块的形状选自长方形、正方形、圆形或菱形。呈阵列排布的长方形、正方形、圆形或菱形地补锂膜块更易于在极片表面形成间隔排布的补锂区和非补锂区，进而提供长程有序的通道，以获得更好的补锂效果。可选的，所述补锂膜块的形状选自长方形、正方形、或菱形。可选的，所述补锂膜块的形状选自正方形。In some embodiments, optionally, the shape of the lithium supplement film block is selected from a rectangle, a square, a circle, or a rhombus. Rectangular, square, circular or diamond-shaped lithium-supplementing film blocks arranged in an array are easier to form spaced lithium-supplemented and non-supplemented areas on the surface of the pole piece, thereby providing a long-range orderly channel for better The effect of replenishing lithium. Optionally, the shape of the lithium supplement film block is selected from a rectangle, a square, or a rhombus. Optionally, the shape of the lithium supplement film block is selected from a square.

在一些实施方式中，当补锂膜块为正方形补锂膜块时，正方形补锂膜块的边长为20μm～5000μm。可选的，正方形补锂膜块的边长为30μm～1500μm，30μm～1000μm，100μm～1500μm，或100μm～1000μm。进一步可选的，相邻两个正方形补锂膜块之间的距离为10μm～2000μm。例如，相邻两个正方形补锂膜块之间的距离为30μm～1500μm， 30μm～1000μm，100μm～1500μm，100μm～1000μm，100μm～500μm，或500μm～1000μm等。In some embodiments, when the lithium supplementary membrane block is a square lithium supplementary membrane block, the side length of the square lithium supplementary membrane block is 20 μm to 5000 μm. Optionally, the side length of the square lithium supplement film block is 30 μm to 1500 μm, 30 μm to 1000 μm, 100 μm to 1500 μm, or 100 μm to 1000 μm. Further optionally, the distance between two adjacent square lithium supplementary film blocks is 10 μm to 2000 μm. For example, the distance between two adjacent square lithium supplementary film blocks is 30 μm to 1500 μm, 30 μm to 1000 μm, 100 μm to 1500 μm, 100 μm to 1000 μm, 100 μm to 500 μm, or 500 μm to 1000 μm.

当补锂膜块为圆形补锂膜块时，圆形补锂膜块的半径为7μm～1000μm，例如8μm～700μm，10μm～500μm，或100μm～500μm等。可选的，相邻两个圆形补锂膜块的中心之间的距离与圆形直径的差(即相邻两个圆形补锂膜块的最短距离)为10μm～1000μm，例如10μm～500μm，或100μm～500μm等。When the lithium supplementary membrane block is a circular lithium supplementary membrane block, the radius of the circular lithium supplementary membrane block is 7 μm to 1000 μm, such as 8 μm to 700 μm, 10 μm to 500 μm, or 100 μm to 500 μm. Optionally, the difference between the distance between the centers of two adjacent circular lithium supplementary membrane blocks and the diameter of the circle (that is, the shortest distance between two adjacent circular lithium supplementary membrane blocks) is 10 μm to 1000 μm, for example, 10 μm to 500μm, or 100μm～500μm, etc.

当补锂膜块的形状为正方形或圆形，且该正方形或圆形补锂膜块的边长/半径、距离在上述范围中，非补锂区所提供的导热通道充足，锂层与活性物质层浸润效果也良好，保证锂层浸润效果，有利于降低电芯内阻，改善电芯循环性能；电解液通过非补锂区域流动，并且锂层在活性材料层表面易于扩散，活性物质与锂层反应热可控，化成后锂层厚度适中，改善散热及电解液浸润性能，可获得较佳的补锂效果。When the shape of the lithium-supplemented membrane block is square or circular, and the side length/radius and distance of the square or circular lithium-supplemented membrane block are within the above range, the heat conduction channel provided by the non-lithium supplementation zone is sufficient, and the lithium layer is active The material layer wetting effect is also good, ensuring the lithium layer wetting effect, which is beneficial to reduce the internal resistance of the cell and improve the cycle performance of the cell; the electrolyte flows through the non-replenishing area, and the lithium layer is easy to diffuse on the surface of the active material layer. The reaction heat of the lithium layer is controllable, the thickness of the lithium layer after formation is moderate, the heat dissipation and electrolyte infiltration performance are improved, and a better lithium supplement effect can be obtained.

在本申请中，补锂膜块的尺寸参数(例如厚度、边长、距离等)可采用本领域已知的方法进行测定。例如采用SEM(例如蔡司SIGMA 500高分辨率场发射扫描电镜)扫描测试。例如，补锂膜块的厚度的示例性测试方法如下，取相应的极片样品，制备该极片厚度方向上的断面，例如使用截面抛光仪(如JEOL IB-09010CP)制备所述断面；然后使用SEM(如SIGMA 500)测试补锂膜块的厚度。测试时，可以取多个(例如10个)补锂膜块分别测试厚度，取其平均值作为该补锂负极极片中补锂膜块的厚度。In this application, the dimensional parameters (such as thickness, side length, distance, etc.) of the lithium-supplemented membrane block can be measured by methods known in the art. For example, SEM (such as Zeiss SIGMA 500 high-resolution field emission scanning electron microscope) is used for scanning test. For example, an exemplary test method for the thickness of the lithium-replenishing membrane block is as follows: take a corresponding pole piece sample and prepare a section in the thickness direction of the pole piece, for example, use a section polisher (such as JEOL IB-09010CP) to prepare the section; Use SEM (such as SIGMA 500) to test the thickness of the lithium supplement film. During the test, a plurality of (for example, 10) lithium supplementary film blocks can be used to test the thickness respectively, and the average value thereof is taken as the thickness of the lithium supplementary film block in the lithium supplementary negative electrode piece.

在本申请的补锂负极极片中，所述补锂氧化层可包括选自单质锂、氧化锂、氮化锂、氟化锂、氢氧化锂、碳酸锂、碳化锂、锂硅合金中的一种或多种的混合物。In the lithium-supplementing negative pole piece of the present application, the lithium-supplementing oxide layer may include a material selected from elemental lithium, lithium oxide, lithium nitride, lithium fluoride, lithium hydroxide, lithium carbonate, lithium carbide, and lithium silicon alloy. One or more mixtures.

在本申请的补锂负极极片中，所述补锂膜块的原料可选自锂粉、锂锭和锂片中的一种或多种。可选的，所述补锂膜块的原料选自锂粉。例如，所述补锂膜块为由锂粉浆料涂布，并经干燥而成的，所述锂粉浆料包含锂粉和有机溶剂。In the lithium-supplementing negative electrode sheet of the present application, the raw material of the lithium-supplementing membrane block can be selected from one or more of lithium powder, lithium ingot and lithium sheet. Optionally, the raw material of the lithium supplement membrane block is selected from lithium powder. For example, the lithium supplementary membrane block is formed by coating and drying a lithium powder slurry, and the lithium powder slurry includes lithium powder and an organic solvent.

在本申请的补锂负极极片中，负极活性物质可包括硅基材料。硅基材料可选自Si、Sn、SiOx、Si/C(硅碳复合材料)、Si的卤化物、Si合金中的一种或几种物质，其中0<x<2。可选的，硅基材料包括SiOx，例如氧化亚硅SiO。In the lithium-supplemented negative electrode sheet of the present application, the negative electrode active material may include a silicon-based material. The silicon-based material can be selected from one or more of Si, Sn, SiOx, Si/C (silicon-carbon composite), Si halide, and Si alloy, where 0<x<2. Optionally, the silicon-based material includes SiOx, such as silicon oxide SiO.

在一些实施方式中，负极活性物质还可包括其它负极活性材料。例如石墨(例如人造石墨、天然石墨)、无定形碳、锡基材料(例如SnOy，0<y<2、Sn/C、Sn的卤化物、Sn合金等)等。In some embodiments, the negative active material may further include other negative active materials. For example, graphite (for example, artificial graphite, natural graphite), amorphous carbon, tin-based materials (for example, SnOy, 0<y<2, Sn/C, Sn halide, Sn alloy, etc.).

在一些实施方式中，负极活性物质包括硅基材料和石墨。可选的，硅基材料包括SiOx，例如SiO。可选的，石墨包括人造石墨。作为具体的示例，负极活性物质可包括氧化亚硅和人造石墨，其中氧化亚硅和人造石墨的质量比可以为1:9～9:1，2:8～5:5，或2:8～3:7。In some embodiments, the negative active material includes silicon-based materials and graphite. Optionally, the silicon-based material includes SiOx, such as SiO. Optionally, graphite includes artificial graphite. As a specific example, the negative electrode active material may include silicon oxide and artificial graphite, wherein the mass ratio of silicon oxide and artificial graphite may be 1:9-9:1, 2:8-5:5, or 2:8~ 3:7.

本申请还提供锂离子电池，包括正极极片、负极极片、间隔于所述正极极片和所述负极极片之间的隔离膜、电解液，所述负极极片采用本申请提供的任意一种补锂负极极片。This application also provides a lithium ion battery, including a positive pole piece, a negative pole piece, a separator spaced between the positive pole piece and the negative pole piece, and an electrolyte. The negative pole piece adopts any of the A negative pole piece for replenishing lithium.

在本申请的锂离子电池中，正极极片、负极极片和隔离膜可经叠片工艺形成叠片式电芯，或经卷绕工艺形成卷绕式电芯。In the lithium ion battery of the present application, the positive pole piece, the negative pole piece and the separator can be formed into a laminated cell through a lamination process, or a wound cell through a winding process.

采用本申请的补锂负极极片的卷绕式电芯，能在拐角处形成一定间隙，在电池循环过程中为极片的膨胀提供可使用的空间。一方面，可避免缓解极片膨胀引起的极片断裂、甚至刺穿隔离膜的安全风险。另一方面，也可保证拐角处的空气流通，利于散热，防止因为空气流通不畅导致卷绕后的补锂电芯拐角发黑的问题，从而提高补锂电池的锂利用率，并进一步改善电池的循环性能。The wound battery cell using the lithium-supplemented negative pole piece of the present application can form a certain gap at the corner and provide usable space for the expansion of the pole piece during the battery cycle. On the one hand, it can avoid alleviating the safety risk of pole piece fracture caused by pole piece expansion and even piercing the isolation membrane. On the other hand, it can also ensure the air circulation at the corners, which is conducive to heat dissipation and prevent the corners of the wound lithium battery from turning black due to poor air circulation, thereby increasing the lithium utilization rate of the lithium battery and further improving the battery Cycle performance.

在一些实施方式中，所述卷绕式电芯化成后的拐角间隙为为0.1μm～50μm，例如为3μm～30μm，1.5μm～22.5μm，或1.5μm～6μm等。上述拐角间隙对于电池的循环性能和安全稳定性具有显著的作用，能进一步提高补锂电池的锂利用率，并且进一步改善电池的性能，其中可进一步改善电池的循环性能和能量密度。In some embodiments, the corner gap after formation of the wound cell is 0.1 μm to 50 μm, for example, 3 μm to 30 μm, 1.5 μm to 22.5 μm, or 1.5 μm to 6 μm. The above-mentioned corner gap has a significant effect on the cycle performance and safety and stability of the battery, and can further increase the lithium utilization rate of the lithium supplement battery, and further improve the performance of the battery, wherein the cycle performance and energy density of the battery can be further improved.

在一些实施方式中，所述卷绕式电芯化成后，所述负极极片与所述隔离膜之间具有间隙。采用本申请的补锂负极极片的卷绕式电芯中，呈阵列排布的若干补锂膜块本身具备一定高度，化成后，大部分或全部补锂材料扩散至负极活性材料层中，残留的补锂氧化层厚度大幅度减小，由此能在各个位置处的负极极片与隔离膜之间形成一定间隙，在电池循环过程中为极片的膨胀提供可使用的空间，缓解膨胀应力。由此，电芯能保持良好的电解液浸润性和离子传输界面，从而能提高电池的循环性能。另外，因极片膨胀引起的极片断裂、甚至刺穿隔离膜的安全风险也大幅度降低，从而能提高电池的安全性能。In some embodiments, after the wound cell is formed, there is a gap between the negative pole piece and the isolation film. In the wound battery cell using the lithium-supplementing negative pole piece of the present application, the several lithium-supplement membrane blocks arranged in an array have a certain height. After formation, most or all of the lithium-supplement material diffuses into the negative electrode active material layer. The thickness of the remaining lithium-supplementing oxide layer is greatly reduced, which can form a certain gap between the negative pole piece and the separator at each position, providing usable space for the expansion of the pole piece during the battery cycle, and alleviating the expansion stress. Thus, the battery cell can maintain good electrolyte wettability and ion transport interface, thereby improving the cycle performance of the battery. In addition, the safety risk of the pole piece breaking or even piercing the isolation membrane caused by the expansion of the pole piece is greatly reduced, thereby improving the safety performance of the battery.

在一些实施方式中，所述卷绕式电芯化成后，所述负极极片与所述隔离膜之间的间隙为0.1μm～50μm，可选的为3μm～30μm，可选的为1.5μm～6μm，1μm～5μm，1μm～3μm，2μm～4μm，或0.5μm～4μm等。当化成后的卷绕式电芯中负极极片与隔离膜之间的间隙在上述范围时，能更好地发挥上述效果，采用其的电池能获得更高的循环性能，同时还可获得较高的安全性能和能量密度。In some embodiments, after the wound cell is formed, the gap between the negative pole piece and the isolation film is 0.1 μm to 50 μm, optionally 3 μm to 30 μm, and optionally 1.5 μm ～6μm, 1μm～5μm, 1μm～3μm, 2μm～4μm, or 0.5μm～4μm, etc. When the gap between the negative pole piece and the separator in the wound cell after formation is in the above range, the above effect can be better exerted, and the battery using it can achieve higher cycle performance, and at the same time, it can also achieve better performance. High safety performance and energy density.

在本申请中，化成后的卷绕式电芯中负极极片与隔离膜之间的间隙GAP＝L+c-(L'+c')，其中，L表示化成前负极活性材料层的厚度(μm)；c表示化成前补锂膜块的厚度(μm)；L'表示化成后负极活性材料层的厚度(μm)；c'表示化成后补锂膜块残留的补锂氧化层的厚度(μm)。厚度c可按前文所述的方法测定。厚度L、L'+c'可采用万分尺或高度规(例如万分尺)测量。测试时，可以测得电芯的多个(例如10个)不同位置处的间隙，取其平均值作为GAP。In this application, the gap between the negative pole piece and the separator in the wound cell after formation GAP=L+c-(L'+c'), where L represents the thickness of the negative electrode active material layer before formation (μm); c represents the thickness of the lithium replenishment film block before chemical conversion (μm); L'represents the thickness of the negative electrode active material layer after chemical conversion (μm); c’ represents the thickness of the lithium replenishment oxide layer remaining in the lithium replenishment film block after chemical conversion (μm). The thickness c can be measured as described above. The thickness L and L'+c' can be measured with a ten-meter ruler or a height gauge (for example, a ten-meter ruler). During the test, the gaps at multiple (for example, 10) different positions of the cell can be measured, and the average value thereof is taken as the GAP.

在本申请的锂离子电池中，正极极片包括正极集流体以及设置在正极集流体至少一个表面上的正极活性物质层。正极极片中，所述正极活性物质层可设置在正极集流体的其中一个表面上也可以设置在正极集流体的两个表面上。正极活性物质层包括正极活性材料，以及可选的粘结剂和可选的导电剂。对各材料的选择没有特别的限制，可根据需求进行选择。例如，正极活性材料可包括锂镍钴锰氧化物(例如LiNi _0.8Co _0.1Mn _0.1O ₂等)等。粘结剂可包括聚偏氟乙烯(PVDF)等。导电剂可包括导电碳等。 In the lithium ion battery of the present application, the positive pole piece includes a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector. In the positive pole piece, the positive electrode active material layer may be provided on one surface of the positive electrode current collector or on both surfaces of the positive electrode current collector. The positive active material layer includes a positive active material, an optional binder and an optional conductive agent. There are no special restrictions on the selection of each material, and it can be selected according to requirements. For example, the positive electrode active material may include lithium nickel cobalt manganese oxide (for example, LiNi _0.8 Co _0.1 Mn _0.1 O ₂ etc.) and the like. The binder may include polyvinylidene fluoride (PVDF) and the like. The conductive agent may include conductive carbon and the like.

在本申请的锂离子电池中，隔离膜可以是本领域各种适用于电化学储能装置隔离膜的材料。例如，隔离膜可包括但不限于聚乙烯、聚丙烯、聚偏氟乙烯、芳纶、聚对苯二甲酸乙二醇酯、聚四氟乙烯、聚丙烯腈、聚酰亚胺，聚酰胺、聚酯和天然纤维中的一种或多种的组合。In the lithium ion battery of the present application, the isolation film can be various materials suitable for the isolation film of electrochemical energy storage devices in the field. For example, the isolation film may include, but is not limited to, polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, A combination of one or more of polyester and natural fibers.

在本申请的锂离子电池中，电解液可以是本领域各种适用于电化学储能装置的电解液。例如，所述电解液通常包括电解质和溶剂。所述电解质通常可以包括锂盐。更具体的，所述锂盐可以是无机锂盐和/或有机锂盐，具体可包括但不限于LiPF ₆、LiBF ₄、LiN(SO ₂F) ₂(简写为LiFSI)、LiN(CF ₃SO ₂) ₂(简写为LiTFSI)、LiClO ₄、LiAsF ₆、LiB(C2O ₄) ₂(简写为LiBOB)、LiBF ₂C ₂O ₄(简写为LiDFOB)中的一种或多种的组合。可选的，所述电解质的浓度可以为0.8mol/L～1.5mol/L。所述溶剂可以是本领域各种适用于电化学储能装置的电解液的溶剂。所述电解液的溶剂通常为非水溶剂，可选为有机溶剂。作为示例，溶剂可包括但不限于碳酸亚乙酯、碳酸亚丙酯、碳酸亚丁酯、碳酸亚戊酯、碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲乙酯或它们的卤代衍生物中的一种或多种的组合。 In the lithium ion battery of the present application, the electrolyte may be various electrolytes suitable for electrochemical energy storage devices in the field. For example, the electrolyte usually includes an electrolyte and a solvent. The electrolyte may generally include a lithium salt. More specifically, the lithium salt may be an inorganic lithium salt and/or an organic lithium salt, which may specifically include but not limited to LiPF ₆ , LiBF ₄ , LiN(SO ₂ F) ₂ (abbreviated as LiFSI), LiN(CF ₃ SO ₂ ) ₂ (abbreviated as LiTFSI), LiClO ₄ , LiAsF ₆ , LiB(C2O ₄ ) ₂ (abbreviated as LiBOB), LiBF ₂ C ₂ O ₄ (abbreviated as LiDFOB), one or a combination of more. Optionally, the concentration of the electrolyte may be 0.8 mol/L to 1.5 mol/L. The solvent may be various solvents in the field suitable for the electrolyte of the electrochemical energy storage device. The solvent of the electrolyte is usually a non-aqueous solvent, and may be an organic solvent. As an example, the solvent may include, but is not limited to, ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, or their One or more combinations of halogenated derivatives.

本申请所提供的补锂负极极片和锂离子电池可按照如下方法制备：The lithium-supplementing negative pole piece and lithium-ion battery provided in this application can be prepared as follows:

(1)制备补锂负极极片。(1) Preparation of lithium supplement negative pole piece.

(a)提供待补锂的负极极片，所述待补锂的负极极片包括负极集流体以及设置在所述负极集流体至少一个表面上的负极活性材料层。(a) Providing a negative pole piece for lithium to be supplemented, which includes a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector.

(b)在所述负极活性材料层远离所述负极集流体的表面上形成呈阵列排布的若干补锂膜块，得到补锂负极极片。(b) forming a plurality of lithium supplement film blocks arranged in an array on the surface of the negative electrode active material layer away from the negative electrode current collector to obtain a lithium supplement negative pole piece.

按照本领域常规方法制备待补锂的负极极片。例如将负极浆料涂布于负极集流体，经干燥、冷压，得到待补锂的负极极片。负极浆料通常包含负极活性材料，可选的导电剂，可选的粘结剂，及其它可选助剂。然后，对待补锂的负极极片进行预补锂，补锂方法可以为：将锂粉与有机溶剂混合，形成锂粉浆料，使用丝网(根据所需的补锂膜块排布结构和补锂膜块形状，选用不同的丝孔结构)覆盖在极片表面，锂粉浆料通过丝网均匀涂覆在极片表面，烘干，形成补锂膜块，即制成补锂负极极片。The negative pole piece of lithium to be supplemented is prepared according to the conventional method in the art. For example, the negative electrode slurry is coated on the negative electrode current collector, dried and cold pressed to obtain a negative electrode piece for lithium to be supplemented. The negative electrode slurry usually contains a negative electrode active material, an optional conductive agent, an optional binder, and other optional additives. Then, the negative pole piece to be supplemented with lithium is pre-charged with lithium. The method for supplementing lithium can be: mixing lithium powder with an organic solvent to form a lithium powder slurry, using a wire mesh (according to the required lithium-supplement film block arrangement and structure Lithium-replenishing membrane block shape, select different wire hole structures) to cover the surface of the pole piece, the lithium powder slurry is evenly coated on the surface of the pole piece through the wire mesh, and dried to form a lithium-replenishing membrane block, which is then made into a lithium-replenishing negative electrode sheet.

可选的，用于锂粉浆料的有机溶剂可采用电解液的溶剂，例如本文所描述的电解液的溶剂。可选的，用于锂粉浆料的有机溶剂包括碳酸亚乙酯。Optionally, the organic solvent used for the lithium powder slurry may be the solvent of the electrolyte, for example, the solvent of the electrolyte described herein. Optionally, the organic solvent used for the lithium powder slurry includes ethylene carbonate.

可选的，在锂粉浆料中，锂粉与有机溶剂的重量比可以为30:70～70:30，例如40:60～60:40，再例如50:50。Optionally, in the lithium powder slurry, the weight ratio of the lithium powder to the organic solvent may be 30:70 to 70:30, for example, 40:60 to 60:40, or for example 50:50.

可选的，涂覆锂粉浆料后进行烘干的温度可以为25℃～35℃，例如30℃～35℃。Optionally, the drying temperature after coating the lithium powder slurry may be 25°C to 35°C, for example, 30°C to 35°C.

(2)按照本领域常规方法制备正极极片、隔离膜和电解液，还可以通过商购获得。(2) The positive pole piece, separator and electrolyte are prepared according to conventional methods in the field, and they can also be obtained commercially.

本领域技术人员可选择合适的方法制备所述正极极片。例如，正极极片的制备可以包括如下步骤：将正极活性材料、粘结剂、导电剂混合形成浆料后，涂布于正极集流体上。Those skilled in the art can choose a suitable method to prepare the positive pole piece. For example, the preparation of the positive pole piece may include the following steps: after mixing the positive electrode active material, the binder, and the conductive agent to form a slurry, it is coated on the positive electrode current collector.

(3)将正极极片、补锂负极极片、间隔于正极极片和补锂负极极片之间的隔离膜卷绕组装，注入电解液，制成锂离子电池。(3) The positive pole piece, the lithium supplement negative pole piece, and the separator between the positive pole piece and the lithium supplement negative pole piece are wound and assembled, and electrolyte is injected to form a lithium ion battery.

图1和图2为作为一个示例的补锂负极极片的结构示意图。补锂负极极片10包括负极集流体11以及设置在所述负极集流体11表面上的负极活性材料层12；所述负极活性材料层12远离所述负极集流体11的表面上呈阵列排布有若干补锂膜块13。补锂膜块13为边长为a的正方形。相邻补锂膜块13之间的距离为b。各补锂膜块13的厚度为c。a、b和c的值可以是本文所描述的。Fig. 1 and Fig. 2 are schematic diagrams of the structure of a lithium supplement negative pole piece as an example. The lithium-supplementing negative electrode piece 10 includes a negative electrode current collector 11 and a negative electrode active material layer 12 disposed on the surface of the negative electrode current collector 11; the negative electrode active material layer 12 is arranged in an array on the surface away from the negative electrode current collector 11 There are several lithium supplementary film blocks 13. The lithium supplement film block 13 is a square with a side length. The distance between adjacent lithium supplementary film blocks 13 is b. The thickness of each lithium supplement film block 13 is c. The values of a, b, and c can be as described herein.

图3是图1和图2所示补锂负极极片10化成后的的结构示意图。若干补锂膜块13残留的补锂氧化层13'在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀为30％～99％。 3 is a schematic diagram of the structure of the lithium supplemental negative electrode 10 shown in FIGS. 1 and 2 after being formed. The ratio S ₁ /S ₀ of the sum S ₁ of the projected area of the remaining lithium supplement oxide layer 13 ′ on the negative electrode active material layer of the several lithium supplement film blocks 13 and the area S ₀ of the negative electrode active material layer is 30%-99%.

可以理解的是，可以在负极集流体的两侧表面上分别形成负极活性材料层和所述阵列排布的补锂膜块。It is understandable that the negative active material layer and the lithium supplement film blocks arranged in the array can be formed on both surfaces of the negative current collector, respectively.

图4是作为一个示例的卷绕式电芯化成后的局部示意图。卷绕式电芯是由补锂负极极片10、隔离膜20和正极极片30经卷绕工艺而成的。其中，隔离膜20介于正极极片30和补锂负极极片10之间起到隔离的作用。由于补锂负极极片10上具有呈阵列排布有若干补锂膜块13，化成后补锂膜块13形成厚度显著减薄的补锂氧化层13'，使得该卷绕式电芯在负极极片10与隔离膜20之间形成间隙d。Fig. 4 is a partial schematic diagram of a wound cell after formation as an example. The wound cell is formed by a lithium-replenishing negative pole piece 10, a separator 20 and a positive pole piece 30 through a winding process. Wherein, the separator 20 is interposed between the positive pole piece 30 and the lithium supplement negative pole piece 10 to play a role of isolation. Since the lithium-supplementing negative pole piece 10 has a number of lithium-supplementing film blocks 13 arranged in an array, the lithium-supplementing film blocks 13 form a lithium-supplementing oxide layer 13' with a significantly reduced thickness after formation, so that the wound cell is in the negative electrode A gap d is formed between the pole piece 10 and the isolation film 20.

本申请对锂离子电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图5是作为一个示例的方形结构的锂离子电池5。There is no particular limitation on the shape of the lithium ion battery in this application, and it can be cylindrical, square or any other shape. Fig. 5 shows a lithium-ion battery 5 with a square structure as an example.

在一些实施例中，锂离子电池可包括外包装。该外包装用于封装正极极片、负极极片和电解质。In some embodiments, the lithium ion battery may include an outer packaging. The outer packaging is used to package the positive pole piece, the negative pole piece and the electrolyte.

在一些实施例中，参照图6，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。In some embodiments, referring to FIG. 6, the outer package may include a housing 51 and a cover 53. Wherein, the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The housing 51 has an opening communicating with the containing cavity, and a cover plate 53 can cover the opening to close the containing cavity.

正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电芯52。电芯52封装于所述容纳腔。电解液浸润于电芯52中。锂离子电池5所含电芯52的数量可以为一个或几个，可根据需求来调节。The positive pole piece, the negative pole piece, and the separator may be formed into the cell 52 through a winding process or a lamination process. The battery core 52 is encapsulated in the containing cavity. The electrolyte is infiltrated in the cell 52. The number of cells 52 contained in the lithium ion battery 5 can be one or several, which can be adjusted according to requirements.

在一些实施例中，锂离子电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。锂离子电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，如包括聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。In some embodiments, the outer packaging of the lithium ion battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like. The outer packaging of the lithium ion battery can also be a soft bag, such as a pouch type soft bag. The material of the soft bag can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.

在一些实施例中，锂离子电池可以组装成电池模块，电池模块所含锂离子电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。In some embodiments, lithium ion batteries can be assembled into battery modules, and the number of lithium ion batteries contained in the battery modules can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.

图7是作为一个示例的电池模块4。参照图7，在电池模块4中，多个锂离子电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个锂离子电池5进行固定。FIG. 7 is the battery module 4 as an example. Referring to FIG. 7, in the battery module 4, a plurality of lithium ion batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, it can also be arranged in any other manner. Furthermore, the plurality of lithium ion batteries 5 can be fixed by fasteners.

可选地，电池模块4还可以包括具有容纳空间的外壳，多个锂离子电池5容纳于该容纳空间。Optionally, the battery module 4 may further include a housing having an accommodation space, and a plurality of lithium ion batteries 5 are accommodated in the accommodation space.

在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。In some embodiments, the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

图8和图9是作为一个示例的电池包1。参照图8和图9，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。Figures 8 and 9 show the battery pack 1 as an example. 8 and 9, the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4. Multiple battery modules 4 can be arranged in the battery box in any manner.

本申请还提供一种装置，所述装置包括本申请所述的锂离子电池、电池模块、或电池包。所述锂离子电池、电池模块或电池包可以用作所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能***等。This application also provides a device, which includes the lithium ion battery, battery module, or battery pack described in this application. The lithium ion battery, battery module or battery pack can be used as the power source of the device, and can also be used as the energy storage unit of the device. The device can be, but is not limited to, mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

所述装置可以根据其使用需求来选择锂离子电池、电池模块或电池包。The device can select a lithium ion battery, battery module or battery pack according to its usage requirements.

图10是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对锂离子电池的高功率和高能量密度的需求，可以采用电池包或电池模块。Fig. 10 is a device as an example. The device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the requirements of the device for high power and high energy density of lithium-ion batteries, battery packs or battery modules can be used.

作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用锂离子电池作为电源。As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device usually requires light and thin, and can use lithium-ion batteries as a power source.

下面结合具体实施例和对比例，进一步阐述本申请。应理解，这些实施例仅用于说明本申请而不用于限制本申请的范围。The application will be further elaborated below in conjunction with specific examples and comparative examples. It should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application.

(1)制备补锂负极极片：(1) Preparation of lithium supplement negative pole piece:

将氧化亚硅和人造石墨按质量比3:7混合得到负极活性物质，然后将负极活性物质、负极粘结剂丁苯橡胶、增稠剂羧甲基纤维素钠CMC-Na、负极导电剂导电碳黑Super P按质量比96:2:1:1分散于溶剂去离子水中，混合均匀制成负极浆料；之后按照130mg/1540mm ²的涂覆重量将负极浆料均匀涂覆在负极集流体铜箔的正反两面上，经过85℃烤箱烘干后，再经冷压等工序，制备成初始负极极片。 Mix silicon oxide and artificial graphite at a mass ratio of 3:7 to obtain the negative active material, and then conduct the negative active material, negative binder styrene butadiene rubber, thickener sodium carboxymethyl cellulose CMC-Na, and negative conductive agent. Carbon black Super P is dispersed in the solvent deionized water at a mass ratio of 96:2:1:1 and mixed uniformly to make a negative electrode slurry; then the negative electrode slurry is evenly coated on the negative electrode current collector according to the coating weight of 130mg/1540mm ² The front and back sides of the copper foil are dried in an oven at 85°C, and then subjected to processes such as cold pressing to prepare initial negative pole pieces.

将锂粉与有机溶剂(碳酸亚乙酯)按重量比50:50均匀混合，形成锂粉浆料；使用丝网(按照表1参数根据所需补锂膜块排布结构和补锂膜块形状，选用不同的丝孔结构)覆盖在负极极片表面，锂粉浆料通过丝网均匀涂覆在负极极片表面，形成呈阵列排布有若干补锂膜块，然后将极片放置在35℃烘箱烘干后制成补锂负极极片。Mix the lithium powder and organic solvent (ethylene carbonate) uniformly at a weight ratio of 50:50 to form a lithium powder slurry; use a wire mesh (according to the parameters in Table 1 according to the required lithium-replenishing membrane block arrangement structure and lithium-replenishing membrane block Shape, choose different wire hole structures) to cover the surface of the negative pole piece, and the lithium powder slurry is evenly coated on the surface of the negative pole piece through the wire mesh to form an array with several lithium supplement film blocks, and then place the pole piece on After being dried in an oven at 35°C, a lithium-replenishing negative pole piece is made.

(2)按照本领域常规方法制备正极极片、隔离膜和电解液。(2) Prepare the positive pole piece, separator and electrolyte according to conventional methods in the field.

正极极片：将LiNi _0.8Co _0.1Mn _0.1O ₂，导电剂导电碳，粘结剂聚偏氟乙烯(PVDF)按质量比96:2:2混合均匀，制成具有一定粘度的锂离子电池正极浆料；将所述正极浆料涂布在集流体铝箔上，85℃下烘干后冷压，再进行切边，裁片，分条，分条后在真空条件下及温度为85℃下烘干4小时，焊接极耳，做成锂电池正极极片。 Positive pole piece: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , conductive agent conductive carbon, and binder polyvinylidene fluoride (PVDF) are mixed uniformly at a mass ratio of 96:2:2 to make a lithium ion battery positive electrode with a certain viscosity Slurry; The positive electrode slurry is coated on the current collector aluminum foil, dried at 85 ℃ and then cold pressed, and then trimmed, sliced, slitted, and then slitted under vacuum and at a temperature of 85 ℃ Dry for 4 hours and weld the tabs to make the positive pole piece of the lithium battery.

隔离膜：多孔基材隔膜材料选用16μm厚度的聚乙烯微孔薄膜。Isolation membrane: The porous base material is a polyethylene microporous membrane with a thickness of 16μm.

电解液：将六氟磷酸锂溶解于碳酸亚乙酯，碳酸二甲酯及碳酸甲乙酯组成的混合溶剂中，三组分体积比为1:2:1，得到所需电解液。Electrolyte: Dissolve lithium hexafluorophosphate in a mixed solvent composed of ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, and the volume ratio of the three components is 1:2:1 to obtain the required electrolyte.

(3)制备锂离子电池(3) Preparation of lithium ion batteries

将正极极片、补锂负极极片、间隔于正极极片和补锂负极极片之间的隔离膜卷绕组装，注入电解液，制成锂离子电池。The positive pole piece, the lithium supplementary negative pole piece, and the separator film separated between the positive pole piece and the lithium supplementary negative pole piece are wound and assembled, and electrolyte is injected to form a lithium ion battery.

按照上述方法制备本申请实施例1～32和对比例1～3中的补锂负极极片及锂离子电池，其中各实施例中的补锂层的具体参数如表1所示。对比例1与实施例1的区别在于，对比例1中的锂离子电池的负极极片没有进行补锂；对比例2与实施例1的区别在于对比例2中的锂离子电池进行了全面补锂。本申请以对比例1～3中的锂离子电池作为对照。The lithium-supplementing negative pole pieces and lithium-ion batteries in Examples 1 to 32 of the present application and Comparative Examples 1 to 3 were prepared according to the above method, and the specific parameters of the lithium supplementing layer in each embodiment are shown in Table 1. The difference between Comparative Example 1 and Example 1 is that the negative pole piece of the lithium ion battery in Comparative Example 1 is not supplemented with lithium; the difference between Comparative Example 2 and Example 1 is that the lithium ion battery in Comparative Example 2 is fully supplemented. lithium. This application uses the lithium ion batteries in Comparative Examples 1 to 3 as a control.

对实施例1～32和对比例1～3中的负极极片和锂离子电池进行如下检测：The negative pole pieces and lithium ion batteries in Examples 1 to 32 and Comparative Examples 1 to 3 were tested as follows:

(1)补锂氧化层覆盖面积比：极片化成后，拆解电池，裁取补锂负极极片样品；分别测量若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁、负极活性材料层的面积S ₀，计算比值S ₁/S ₀。本申请的实施方式中，S ₁/S ₀的合理范围为30％～99％，可选40％～98％。 (1) Lithium supplementation oxide layer coverage area ratio: After the pole pieces are formed, disassemble the battery and cut samples of the lithium supplementation negative pole piece; measure the projections of the remaining lithium supplementation oxide layers of several lithium supplementation film blocks on the negative electrode active material layer. The area sum S ₁ and the area S _{0 of the} negative electrode active material layer are calculated as the ratio S ₁ /S ₀ . In the embodiment of the present application, the reasonable range of S ₁ /S ₀ is 30% to 99%, and 40% to 98% can be selected.

(2)极片温度测试：补锂极片用6英寸卷筒收卷1000m，在收卷500m处***感温线测试极片温度，测温仪器为：测温仪：SKF TKDT 10。(2) Pole piece temperature test: Rewind the lithium pole piece with a 6-inch reel for 1000m, and insert a temperature sensing wire at 500m to test the temperature of the pole piece. The temperature measuring instrument is: Thermometer: SKF TKDT 10.

(3)浸润效果：即电池化成后的极片浸润电解液效果。化成是指对注液后的电芯进行首次充放电。充放电设备：新威移动电源成品专用测试仪(6V4A)。将锂离子电池以1C电流倍率充电至4.2V电压，以1C电流倍率放电至3.0V。化成后拆电芯观察到的极片界面即为化成界面，化成界面中如果残留具有金属光泽的锂箔金属，则化成界面判定NG；如果无残留具有金属光泽的锂箔金属，则界面判定为OK。(3) Wetting effect: that is, the effect of infiltrating the electrolyte into the pole pieces of the battery. Formation refers to the first charging and discharging of the cells after liquid injection. Charging and discharging equipment: Xinwei mobile power supply product dedicated tester (6V4A). The lithium ion battery is charged to 4.2V at a current rate of 1C and discharged to 3.0V at a current rate of 1C. The pole piece interface observed when the battery cell is removed after chemical conversion is the chemical conversion interface. If the metallic lithium foil metal remains in the chemical conversion interface, the chemical conversion interface is judged as NG; if there is no metallic lithium foil metal remaining, the interface is judged as OK.

(4)电芯内阻：即交流电阻，交流内阻设备：Itech公司IT5100系列电池内阻测试仪。测试方法：对测试电芯加固定频率1KHz，固定电流50mA，对电压采样，经整流仪器可计算出阻值。(4) Battery internal resistance: AC resistance, AC internal resistance equipment: IT5100 series battery internal resistance tester from Itech. Test method: add a fixed frequency of 1KHz to the test cell, a fixed current of 50mA, sample the voltage, and calculate the resistance value by a rectifier instrument.

(5)循环性能：对锂离子电池重复进行充放电，直至容量衰减率达到80％的充放电次数。例如：电芯容量为70Ah，重复对电芯进行充放电，当电芯容量衰减至56Ah时，停止测试，记录重复充放电的次数，即为电芯的循环性能数据。(5) Cycle performance: Repeat charging and discharging of the lithium-ion battery until the capacity decay rate reaches 80%. For example, if the cell capacity is 70Ah, charge and discharge the cell repeatedly. When the cell capacity decays to 56Ah, stop the test and record the number of repeated charge and discharge, which is the cycle performance data of the cell.

(6)化成前补锂膜块的厚度和化成后补锂氧化层的厚度：使用截面抛光仪(如JEOL IB-09010CP)制备补锂负极极片的厚度方向的断面；使用蔡司SIGMA 500测试补锂膜块的厚度。其中可以取多个(例如10个)补锂膜块分别测试厚度，取其平均值作为该补锂负极极片中补锂膜块的厚度。同理可测定化成后补锂氧化层的厚度。(6) The thickness of the lithium supplement film block before formation and the thickness of the lithium supplement oxide layer after formation: use a cross-section polisher (such as JEOL IB-09010CP) to prepare the thickness direction section of the lithium supplement negative pole piece; use Zeiss SIGMA 500 to test and supplement The thickness of the lithium film block. Among them, a plurality of (for example, 10) lithium supplementary membrane blocks can be used to test the thickness respectively, and the average value thereof is taken as the thickness of the lithium supplementary membrane block in the lithium supplementary negative electrode piece. In the same way, the thickness of the lithium oxide layer after formation can be measured.

下表1为实施例1～32和对比例1～3的具体参数和测试结果：Table 1 below shows the specific parameters and test results of Examples 1 to 32 and Comparative Examples 1 to 3:

表1 实施例及对比例的具体参数和测试结果Table 1 Specific parameters and test results of Examples and Comparative Examples

由表1数据可知，实施例1～33的性能数据整体上优于对比例1～3，说明本申请实施方式中的补锂方式，已显著达到了减小电芯内阻、改善电池的循环性能、提高安全性的效果。下面，针对补锂膜块的各项参数对电池性能的不同影响分别进行讨论。From the data in Table 1, it can be seen that the performance data of Examples 1 to 33 are better than Comparative Examples 1 to 3 on the whole, indicating that the lithium supplement method in the implementation of this application has significantly reduced the internal resistance of the battery cell and improved the cycle of the battery. The effect of improving performance and safety. In the following, the different effects of various parameters of the replenishing lithium membrane block on the battery performance are discussed separately.

(一)实施例1～6和对比例1～3的对比，显示了改变若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀对补锂效果的影响。 (1) The comparison between Examples 1 to 6 and Comparative Examples 1 to 3 shows that the sum of the projected areas of the lithium-supplementing oxide layer on the negative electrode active material layer and the difference between the sum of S ₁ and the negative electrode active material layer are changed. The influence of the area S ₀ ratio S ₁ /S ₀ on the effect of lithium supplementation.

在相同负极材料、相同补锂膜块排布和形状、相同补锂厚度的情况下，减小S ₁/S ₀(减小补锂区面积、增大非补锂区面积)，则可提供足够长、宽的导热通道，便于锂嵌入活性物质时产生热量的散发，提高补锂过程中的安全性。 In the case of the same negative electrode material, the same arrangement and shape of the lithium-supplementing membrane block, and the same lithium-supplement thickness, reducing S ₁ /S ₀ (reducing the area of the lithium-supplement area and increasing the area of the non-lithium-supplementing area) can provide A sufficiently long and wide heat conduction channel facilitates the dissipation of heat generated when lithium is inserted into the active material, and improves the safety in the process of replenishing lithium.

但是，当S ₁/S ₀过小，如S ₁/S ₀＜30％(如对比例3)，补锂区覆盖面积过小，则会出现以下问题：活性材料层表面的补锂区锂层压实密度过大，即补锂区面积S ₁上的实际锂层重量较大，虽然非补锂区有较多空间可以让补锂区的锂层扩散至非补锂区，但对比锂层垂直方向嵌入活性物质速率，补锂区往非补锂区扩散嵌入的速率要低，所以活性材料层表面容易出现锂层无法完全嵌入、导致化成界面出现析锂，电芯内阻增加，最终影响极片和电池性能的提升。此外，由于注液后锂层嵌入活性物质层不良，也导致化成后锂层厚度仍然较厚，最终影响电池性能。因而，本申请实施方式中S ₁/S ₀的范围应大于30％。 However, when S ₁ /S _{0 is} too small, such as S ₁ /S ₀ <30% (as in Comparative Example 3), and the coverage area of the lithium supplementation area is too small, the following problems will occur: The lithium supplementation area on the surface of the active material layer The compaction density is too large, that is, the actual weight of the lithium layer on the area S ₁ of the lithium supplementation area is larger. Although the non-lithium supplementation area has more space for the lithium layer of the lithium supplementation area to diffuse to the non-lithium supplementation area, it is compared with lithium The rate of intercalation of the active material in the vertical direction of the layer, the diffusion and intercalation rate of the lithium-supplemented area to the non-supplemented area is low, so the surface of the active material layer is prone to be unable to fully intercalate the lithium layer, resulting in lithium evolution at the formation interface, and the internal resistance of the battery increases. Affect the improvement of pole piece and battery performance. In addition, due to the poor insertion of the lithium layer into the active material layer after liquid injection, the thickness of the lithium layer is still thick after formation, which ultimately affects the battery performance. Therefore, the range of S ₁ /S ₀ in the embodiment of the present application should be greater than 30%.

反之，当S ₁/S ₀过大，如S ₁/S ₀达到了99％(实施例6)，补锂区覆盖面积已非常大，如果再增加S ₁/S ₀则会出现以下问题：当S ₁/S ₀过大，活性材料层与锂层接触和反应的表面积也过大，锂层嵌入活性物质反应发热，导致极片发热严重。同时，非补锂区面积过小，无法提供足够导热通道。一方面，造成极片温度过高、降低锂层的活性，在高温条件下有部分锂层形成死锂，无法用于提供容量，导致电池的电性能下降、循环性能变差。另一方面，极片温度过高也可引起电池制造过程中的安全问题。此外，由于活性材料层与锂层反应的表面积大大增加，注液后，静置过程中锂层嵌入活性材料层的速率加快，化成后锂层厚度大幅度减小。由于化成的锂层厚度可以对活性物质的膨胀起到抑制作用，从而改善循环过程中的极片膨胀而导致的性能衰减，因此，补锂区覆盖面积过大还会影响电芯循环性能的提升。 Conversely, when S ₁ /S _{0 is} too large, such as S ₁ /S ₀ reaches 99% (Example 6), the coverage area of the lithium supplementation area is already very large. If S ₁ /S ₀ is increased, the following problems will occur: When S ₁ /S _{0 is} too large, the surface area where the active material layer contacts and reacts with the lithium layer is also too large, and the lithium layer intercalates into the active material to react and generate heat, which causes severe heating of the pole piece. At the same time, the area of the non-lithium supplementation area is too small to provide sufficient heat conduction channels. On the one hand, the pole piece temperature is too high and the activity of the lithium layer is reduced. Under high temperature conditions, part of the lithium layer forms dead lithium, which cannot be used to provide capacity, resulting in a decrease in the electrical performance of the battery and poor cycle performance. On the other hand, excessively high pole piece temperature can also cause safety problems in the battery manufacturing process. In addition, since the surface area of the active material layer reacting with the lithium layer is greatly increased, after liquid injection, the rate at which the lithium layer is inserted into the active material layer increases during the standing process, and the thickness of the lithium layer is greatly reduced after formation. Since the thickness of the formed lithium layer can inhibit the expansion of the active material, thereby improving the performance degradation caused by the expansion of the pole piece during the cycle, the excessive coverage of the lithium supplementation area will also affect the improvement of the cycle performance of the cell .

因而，本申请实施方式中，S ₁/S ₀的范围应在30％～99％，例如40％～98％。此时，活性物质与锂层反应热可控，不会因为补锂区覆盖面积S ₁过大导致锂层与活性物质接触面积增加导致发热不可控；也不会因为非补锂区面积过大导致化成界面出现未嵌入的锂层。非补锂区能够提供大小适当的通道，通道中空气流通，将活性物质与锂层发生反应的热量带走，降低极片收卷温度；同时能够保证锂层在活性物质表面有效扩散，降低锂层无法完全嵌入活性物质层的风险。 Therefore, in the embodiment of the present application, the range of S ₁ /S ₀ should be 30% to 99%, for example, 40% to 98%. At this time, the heat of the reaction between the active material and the lithium layer is controllable, and the area of contact between the lithium layer and the active material will not increase due to the excessively large coverage area S ₁ of the lithium supplementation area, and the heating will not be uncontrollable; nor will the area of the non-lithium supplementation area be too large This results in an unintercalated lithium layer at the formation interface. The non-lithium-supplemented area can provide a channel of appropriate size. The air circulates in the channel to take away the heat of the reaction between the active material and the lithium layer and reduce the winding temperature of the pole piece; at the same time, it can ensure the effective diffusion of the lithium layer on the surface of the active material to reduce lithium The risk that the layer cannot be fully embedded in the active material layer.

(二)实施例2和实施例7～11的对比，显示了改变正方形补锂膜块边长对补锂效果的影响。(2) The comparison between Example 2 and Examples 7 to 11 shows the effect of changing the side length of the square lithium supplement film block on the lithium supplement effect.

在相同负极材料、相同补锂膜块排布、形状和厚度、合适的S ₁/S ₀范围内，当正方形补锂膜块的边长过小，如边长比实施例7中的30μm更小，则会出现如下问题：电解液的流通和浸润效果过好，造成化成后锂层厚度大幅度降低。而化成的锂层厚度可以对活性物质的膨胀起到抑制作用，从而改善循环过程中的极片膨胀而导致的性能衰减，因而，补锂膜块的边长过小导致化成后锂层厚度大幅度降低的情况，会影响电芯循环性能的提升。此外，补锂膜块边长过小，也增加补锂工艺的困难度和补锂成本。 In the same negative electrode material, the same arrangement, shape and thickness of the lithium-supplementing membrane block, and within the appropriate range of S ₁ /S ₀ , when the side length of the square lithium-supplementing membrane block is too small, for example, the side length is longer than 30 μm in Example 7. If it is small, the following problem will occur: the electrolyte circulation and wetting effect is too good, resulting in a significant reduction in the thickness of the lithium layer after formation. The thickness of the formed lithium layer can inhibit the expansion of the active material, thereby improving the performance degradation caused by the expansion of the pole piece during the cycle. Therefore, the side length of the lithium supplementary film is too small, resulting in a large thickness of the lithium layer after formation The decrease of the amplitude will affect the improvement of the battery cycle performance. In addition, the side length of the lithium supplement film block is too small, which also increases the difficulty of the lithium supplement process and the cost of lithium supplement.

反之，当正方形补锂膜块边长过大，如边长大于1500μm(如实施例11)，则会出现如下问题：补锂膜块边长的增大，引起局部区域活性物质与锂层反应的表面积增加，锂层嵌入活性物质反应发热，导致极片发热严重、极片温度过高，可能引起电池制造过程中的安全问题。此外，由于补锂膜块边长的增大，局部区域活性材料层与锂层反应的表面积大大增加，注入电解液后，静置过程中锂层嵌入活性材料层的速率加快，化成后锂层厚度大大降低，同样会影响电芯循环性能的提升。Conversely, when the side length of the square lithium supplement film is too large, such as the side length is greater than 1500μm (as in Example 11), the following problem will occur: the increase of the side length of the lithium supplement film will cause the active material in the local area to react with the lithium layer The surface area of the lithium layer increases, and the active material is embedded in the lithium layer to react and generate heat, resulting in serious heating of the pole piece and excessively high temperature of the pole piece, which may cause safety problems in the battery manufacturing process. In addition, due to the increase of the side length of the lithium replenishment film, the surface area of the active material layer and the lithium layer in the local area is greatly increased. After the electrolyte is injected, the rate of insertion of the lithium layer into the active material layer is accelerated during the standing process, and the lithium layer is formed after formation. The thickness is greatly reduced, which will also affect the improvement of the cell cycle performance.

因而，本申请实施方式中，正方形补锂膜块的边长范围为20μm～5000μm，例如30μm～1500μm。此时，电解液通过非补锂区域流动，并且锂层在活性材料层表面易于扩散，活性物质与锂层反应热可控，化成后锂层厚度适中，可改善散热及电解液浸润性能，可获得较佳的补锂效果。Therefore, in the embodiment of the present application, the side length of the square lithium supplementary membrane block ranges from 20 μm to 5000 μm, for example, from 30 μm to 1500 μm. At this time, the electrolyte flows through the non-lithium replenishment area, and the lithium layer is easily diffused on the surface of the active material layer. The reaction heat of the active material and the lithium layer is controllable. After formation, the thickness of the lithium layer is moderate, which can improve the heat dissipation and electrolyte infiltration performance. Obtain a better effect of replenishing lithium.

(三)实施例5、6及12～16的对比，显示了改变正方形补锂膜块之间的距离对补锂效果的影响。(3) The comparison of Examples 5, 6 and 12-16 shows the influence of changing the distance between the square lithium supplementary film blocks on the lithium supplementation effect.

在相同负极材料，相同补锂膜块形状、边长和厚度、合适的S ₁/S ₀范围内，如正方形补锂膜块之间的距离过小，如距离小于30μm，则会出现如下问题：补锂膜块之间的距离小，则无法提供足够的导热通道。一方面，极片温度过高会降低锂层的活性，在高温条件下有部分锂层形成死锂，无法用于提供容量，对电性能有影响，影响电池循环性能的提高。另一方面，极片温度过高也会引起电池制造过程中的安全问题。 In the same negative electrode material, the same shape, side length and thickness of the lithium supplement film block, and within the appropriate range of S ₁ /S ₀ , if the distance between the square lithium supplement film blocks is too small, if the distance is less than 30 μm, the following problems will occur : If the distance between the lithium replenishment film blocks is small, it will not provide enough heat conduction channels. On the one hand, excessively high electrode temperature will reduce the activity of the lithium layer. Under high temperature conditions, some of the lithium layer will form dead lithium, which cannot be used to provide capacity, which will affect the electrical performance and affect the improvement of battery cycle performance. On the other hand, the extremely high temperature of the pole pieces can also cause safety problems in the battery manufacturing process.

反之，如正方形补锂膜块之间的距离过大，如距离大于1500μm，则锂的扩散效果较差，直接影响锂层在活性物质的浸润效果，从而导致电芯内阻增大，增加电芯极化，最终影响电芯循环性能。Conversely, if the distance between the square lithium supplementary film blocks is too large, if the distance is greater than 1500μm, the lithium diffusion effect will be poor, which directly affects the infiltration effect of the lithium layer in the active material, resulting in an increase in the internal resistance of the battery cell and an increase in electricity. The polarization of the core ultimately affects the cycle performance of the cell.

因而，本申请实施方式中，在合适S ₁/S ₀比例范围内，相邻两个正方形补锂膜块之间的距离范围为10μm～2000μm，例如30μm～1500μm。此时，非补锂膜块所提供的导热通道充足，锂层与活性物质层浸润效果也良好，保证锂层浸润效果，有利于降低电芯内阻，并最终改善电芯循环性能。 Therefore, in the embodiments of the present application, within a suitable S ₁ /S ₀ ratio, the distance between two adjacent square lithium supplementary membrane blocks ranges from 10 μm to 2000 μm, for example, from 30 μm to 1500 μm. At this time, the heat conduction channel provided by the non-replenishing lithium membrane block is sufficient, and the lithium layer and the active material layer have a good wetting effect, ensuring the wetting effect of the lithium layer, which is beneficial to reduce the internal resistance of the cell and ultimately improve the cycle performance of the cell.

(四)实施例17～22的对比，显示了改变补锂膜块厚度对补锂效果的影响。(4) The comparison of Examples 17-22 shows the effect of changing the thickness of the lithium supplement film block on the lithium supplement effect.

在相同负极材料，相同补锂膜块排布、形状和边长，合适的S ₁/S ₀范围内，补锂膜块厚度过小，如小于0.5μm(实施例17)，会出现如下问题：(1)在相同补锂量、相同补锂面积下，补锂膜块厚度过小，即补锂区锂层与活性物质层压实程度严重，可导致局部区域锂层与活性物质层反应剧烈，局部区域温度太高，将导致两方面结果。一方面，极片温度过高，从而降低锂层的活性，在高温条件下有部分锂层形成死锂，无法用于提供容量，对电性能有影响，降低电池循环性能。另一方面，极片温度过高，极易引起电池制造过程中的安全问题。(2)补锂膜块厚度过小，导致卷绕后电芯拐角处的间隙过小，无法给极片循环过程中的膨胀预留空间，极片膨胀相互挤压甚至出现极片断裂，导致电芯出现安全风险和、并且电池循环性能衰减过快。(3)极片活性物质层与补锂区锂层压实程度严重，导致注入点解液后，该区域活性物质无法完全吸收锂层的含锂成分物质，直接影响锂层的浸润效果，导致电芯内阻增加，极化严重，最终影响电芯循环性能的提升。 In the same negative electrode material, the same arrangement, shape and side length of the lithium supplement film block, within the appropriate range of S ₁ /S ₀ , the thickness of the lithium supplement film block is too small, such as less than 0.5 μm (Example 17), the following problems will occur : (1) Under the same amount of lithium supplement and the same area of lithium supplement, the thickness of the lithium supplement film is too small, that is, the degree of compaction between the lithium layer and the active material in the lithium supplement area is serious, which may cause the reaction between the lithium layer and the active material layer in a local area Severe, local area temperature is too high, will lead to two results. On the one hand, the pole piece temperature is too high, thereby reducing the activity of the lithium layer. Under high temperature conditions, some of the lithium layer forms dead lithium, which cannot be used to provide capacity, which has an impact on electrical performance and reduces battery cycle performance. On the other hand, the pole piece temperature is too high, which can easily cause safety problems in the battery manufacturing process. (2) The thickness of the lithium replenishment film is too small, resulting in too small gaps at the corners of the battery after winding, and it is impossible to reserve space for the expansion of the pole pieces during the cycle. The pole pieces expand and squeeze each other or even the pole pieces break, resulting in Safety risks and battery cycle performance decay too fast. (3) The active material layer of the pole piece and the lithium replenishment area have a serious degree of compaction. After injecting the spot solution, the active material in this area cannot fully absorb the lithium-containing material of the lithium layer, which directly affects the infiltration effect of the lithium layer. The internal resistance of the cell increases, and the polarization is serious, which ultimately affects the improvement of the cycle performance of the cell.

反之，补锂膜块厚度过大，如厚度比实施例22中的30μm更大，则会出现如下问题：(1)如活性物质表面的总补锂量相同，补锂厚度过大，则锂层处于蓬松状态，补锂区锂层与活性物质层接触效果差。在此条件下，注入电解液后锂的扩散效果也较差，部分锂层无法嵌入活性物质层，导致电芯内阻增加，增加电芯极化，最终影响电芯循环性能。(2)如果活性物质表面的总补锂量不同，总补锂量也过高，则补锂膜块厚度也过大，影响锂层与活性物质层之间的浸润效果，导致化成后补锂膜块厚度过厚，如上所述，化成后补锂膜块厚度过厚将最终影响电芯内阻，导致电芯循环性能变差。(3)此外，补锂层过厚导致拐角处间隙过大，造成拐角处锂离子传输距离变长，容易出现界面析锂等问题，从而增加电芯内阻，影响电芯安全性和循环性能。On the contrary, if the thickness of the lithium supplement film is too large, if the thickness is larger than 30μm in Example 22, the following problems will occur: (1) If the total amount of lithium supplement on the surface of the active material is the same, and the thickness of the lithium supplement is too large, the lithium The layer is in a fluffy state, and the contact effect between the lithium layer and the active material layer in the lithium replenishing area is poor. Under this condition, the diffusion effect of lithium is also poor after the electrolyte is injected, and part of the lithium layer cannot be embedded in the active material layer, resulting in an increase in the internal resistance of the cell, increasing the polarization of the cell, and ultimately affecting the cycle performance of the cell. (2) If the total amount of replenishing lithium on the surface of the active material is different, and the total amount of replenishing lithium is too high, the thickness of the lithium replenishment film is also too large, which affects the infiltration effect between the lithium layer and the active material layer, resulting in replenishment of lithium after formation The thickness of the membrane block is too thick. As mentioned above, the thickness of the lithium supplementary membrane block after formation will eventually affect the internal resistance of the cell, resulting in poor cycle performance of the cell. (3) In addition, if the lithium supplement layer is too thick, the gap at the corner will be too large, which will cause the lithium ion transmission distance at the corner to become longer and prone to problems such as interface lithium deposition, which will increase the internal resistance of the cell and affect the safety and cycle performance of the cell. .

因而，本申请实施方式中，补锂膜块的厚度范围为0.5μm～30μm，例如0.5μm～15μm。此时，补锂区锂层与活性物质层压实程度适中，接触效果较佳，电解液浸润效果较好，能在电芯拐角处形成一定的间隙，给极片在循环过程中的膨胀预留膨胀空间，改善电芯安全性能和循环性能。Therefore, in the embodiment of the present application, the thickness of the lithium supplement film block ranges from 0.5 μm to 30 μm, for example, from 0.5 μm to 15 μm. At this time, the degree of compaction between the lithium layer and the active material in the lithium replenishment zone is moderate, the contact effect is better, the electrolyte infiltration effect is better, and a certain gap can be formed at the corner of the cell, which can prevent the expansion of the pole piece during the cycle. Leave room for expansion to improve the safety performance and cycle performance of the battery cell.

(五)实施例23～27的对比，显示了当补锂膜块形状为圆形、调整圆形补锂膜块的半径，对补锂效果的影响。(5) The comparison of Examples 23-27 shows the effect of adjusting the radius of the circular lithium supplementary membrane block on the lithium supplementation effect when the shape of the lithium supplementary membrane block is circular.

当圆形补锂膜块的半径过小，如半径小于8μm(如实施例23)，则会出现如下问题：相同补锂膜块面积，如补锂膜块半径过小，注入电解液后，由于电解液的流通距离过大，锂层在活性物质表面扩散过快，浸润效果过于显著，造成化成后锂层厚度降低过大，如上所述，化成后锂层厚度大大降低会影响电芯循环性能。When the radius of the circular lithium supplementary membrane is too small, such as the radius is less than 8μm (as in Example 23), the following problem will occur: the same area of the lithium supplementary membrane, if the radius of the lithium supplementary membrane is too small, after the electrolyte is injected, Due to the excessively long circulation distance of the electrolyte, the lithium layer diffuses too fast on the surface of the active material, and the infiltration effect is too significant, resulting in an excessive reduction in the thickness of the lithium layer after formation. As mentioned above, the greatly reduced thickness of the lithium layer after formation will affect the cell cycle performance.

反之，圆形补锂膜块半径过大，如半径大于700μm(实施例27)，则会出现如下问题：(1)半径过大，局部区域活性物质与锂层反应的表面积增加，锂层嵌入活性物质反应发热，导致极片发热严重，极片温度过高，引起电池制造过程中的安全问题。(2)由于半径过大，局部区域活性物质与锂层反应的表面积大大增加，注入点解液后，静置过程中锂层嵌入活性物质的速率过快，化成后锂层厚度大大降低，如前所述，化成后锂层厚度大幅度降低将导致影响电芯循环性能的提升。Conversely, if the radius of the circular lithium supplement film block is too large, if the radius is greater than 700μm (Example 27), the following problems will occur: (1) If the radius is too large, the surface area for the active material in the local area to react with the lithium layer increases, and the lithium layer is embedded The active material reacts and generates heat, causing serious heating of the pole piece, and the temperature of the pole piece is too high, causing safety problems in the battery manufacturing process. (2) Because the radius is too large, the surface area of the active material in the local area to react with the lithium layer is greatly increased. After injecting the spot solution, the rate of insertion of the lithium layer into the active material is too fast during the standing process, and the thickness of the lithium layer is greatly reduced after formation, such as As mentioned above, a significant reduction in the thickness of the lithium layer after formation will result in an increase in the cycle performance of the battery cell.

因而，本申请实施方式中，当补锂膜块为圆形补锂膜块时，圆形补锂膜块的半径为8μm～700μm，例如10μm～500μm。Therefore, in the embodiment of the present application, when the lithium supplementary membrane block is a circular lithium supplementary membrane block, the radius of the circular lithium supplementary membrane block is 8 μm to 700 μm, for example, 10 μm to 500 μm.

(六)实施例28～32显示了当补锂膜块形状为圆形、调整圆形补锂膜块之间的距离，对补锂效果的影响，本申请中相邻圆形补锂膜块的距离为相邻圆形补锂膜块中心距离与圆形补锂膜块直径的差，即为相邻圆形补锂膜块之间的最短距离。(6) Examples 28 to 32 show the effect of adjusting the distance between the circular lithium supplementary membrane blocks on the effect of lithium supplementation when the shape of the lithium supplementary membrane block is circular. In this application, adjacent circular lithium supplementary membrane blocks The distance is the difference between the center distance of adjacent circular lithium supplementary membrane blocks and the diameter of the circular lithium supplementary membrane blocks, that is, the shortest distance between adjacent circular lithium supplementary membrane blocks.

补锂膜块面积相同，相邻圆形补锂膜块之间的距离过小，如小于10μm(实施例28)，则无法提供足够导热通道。一方面，极片温度过高会降低锂层的活性，在高温条件下有部分锂层形成死锂，无法用于提供容量，对电性能有明显影响，降低电池的循环性能。另一方面，极片温度过高也会引起电池制造过程中的安全问题。The area of the lithium supplementary membrane blocks is the same, and the distance between adjacent circular lithium supplementary membrane blocks is too small, such as less than 10 μm (Embodiment 28), it is impossible to provide sufficient heat conduction channels. On the one hand, excessively high pole piece temperature will reduce the activity of the lithium layer. Under high temperature conditions, some of the lithium layer will form dead lithium, which cannot be used to provide capacity, which has a significant impact on electrical performance and reduces the cycle performance of the battery. On the other hand, the extremely high temperature of the pole pieces can also cause safety problems in the battery manufacturing process.

反之，相邻圆形补锂膜块之间的距离过大，如比实施例32中1000μm更大，则锂的扩散效果较差，直接影响锂层在活性物质的浸润效果，从而导致电芯内阻增大，增加电芯极化，最终影响电芯循环性能。On the contrary, if the distance between adjacent circular lithium supplementary film blocks is too large, if it is larger than 1000 μm in Example 32, the lithium diffusion effect is poor, which directly affects the infiltration effect of the lithium layer in the active material, resulting in the battery cell The increase of internal resistance increases the polarization of the cell, which ultimately affects the cycle performance of the cell.

因而，本申请实施方式中，相邻两个圆形补锂膜块的中心之间的距离为10μm～1000μm，例如10μm～500μm。Therefore, in the embodiment of the present application, the distance between the centers of two adjacent circular lithium supplementary membrane blocks is 10 μm to 1000 μm, for example, 10 μm to 500 μm.

根据上述说明书的揭示和教导，本领域技术人员还可以对上述实施方式进行变更和修改。因此，本申请并不局限于上面揭示和描述的具体实施方式，对本申请的一些修改和变更也应当落入本申请的权利要求的保护范围内。此外，尽管本说明书中使用了一些特定的术语，但这些术语只是为了方便说明，并不对本申请构成任何限制。Based on the disclosure and teaching of the foregoing specification, those skilled in the art can also make changes and modifications to the foregoing embodiments. Therefore, this application is not limited to the specific implementations disclosed and described above, and some modifications and changes to this application should also fall within the protection scope of the claims of this application. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the application.

Claims

一种补锂负极极片，包括负极集流体以及设置在所述负极集流体至少一个表面上的负极活性材料层；A lithium-supplementing negative pole piece, comprising a negative current collector and a negative active material layer arranged on at least one surface of the negative current collector;

其中，所述负极活性材料层远离所述负极集流体的表面上呈阵列排布有若干补锂膜块；所述极片化成后，若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀为30％～99％。 Wherein, on the surface of the negative electrode active material layer away from the negative electrode current collector, a number of lithium supplementary film blocks are arranged in an array; after the pole pieces are formed, the remaining lithium supplementary oxide layers of the several lithium supplementary film blocks are on the negative electrode active material. The ratio S ₁ /S ₀ of the sum S ₁ of the projected area on the layer to the area S ₀ of the negative electrode active material layer is 30% to 99%.
根据权利要求1所述的补锂负极极片，其中，S ₁/S ₀为40％～98％；可选的，S ₁/S ₀为50％～78％。 The lithium supplementary negative pole piece according to claim 1, wherein S ₁ /S ₀ is 40% to 98%; optionally, S ₁ /S ₀ is 50% to 78%.
根据权利要求1或2所述的补锂负极极片，其中，所述负极活性材料层中的负极活性物质包含硅基材料，所述补锂膜块的厚度为0.5μm～30μm，可选的为0.5μm～15μm，可选的为1μm～4μm。The lithium supplementary negative pole piece according to claim 1 or 2, wherein the negative active material in the negative active material layer comprises a silicon-based material, and the thickness of the lithium supplementary film block is 0.5 μm-30 μm, optionally It is 0.5μm～15μm, optional 1μm～4μm.
根据权利要求1-3任一项所述的补锂负极极片，其中，所述补锂膜块的形状选自长方形、正方形、圆形或菱形。The lithium-supplementing negative pole piece according to any one of claims 1 to 3, wherein the shape of the lithium-supplementing membrane block is selected from rectangle, square, circle or rhombus.
根据权利要求1-3任一项所述的补锂负极极片，其中，所述补锂膜块为正方形补锂膜块，且所述正方形补锂膜块的边长为20μm～5000μm，可选的为30μm～1500μm，可选的为30μm～1000μm。The lithium-supplementing negative pole piece according to any one of claims 1 to 3, wherein the lithium-supplementing film block is a square lithium-supplementing film block, and the square lithium-supplementing film block has a side length of 20 μm to 5000 μm. The selected one is 30μm～1500μm, and the optional one is 30μm～1000μm.
根据权利要求5所述的补锂负极极片，其中，相邻两个所述正方形补锂膜块之间的距离为10μm～2000μm，可选的为30μm～1500μm，可选的为30μm～1000μm。The lithium supplementary negative pole piece according to claim 5, wherein the distance between two adjacent square lithium supplementary membrane blocks is 10 μm to 2000 μm, optionally 30 μm to 1500 μm, and optionally 30 μm to 1000 μm .
根据权利要求1-3任一项所述的补锂负极极片，其中，所述补锂膜块为圆形补锂膜块，所述圆形补锂膜块的半径为7μm～1000μm，可选的8μm～700μm，可选的为10μm～500μm，可选的为100μm～500μm。The lithium supplementary negative pole piece according to any one of claims 1 to 3, wherein the lithium supplementary film block is a circular lithium supplementary film block, and the radius of the circular lithium supplementary film block is 7 μm to 1000 μm. Select 8μm～700μm, optional 10μm～500μm, optional 100μm～500μm.
根据权利要求7所述的补锂负极极片，其中，相邻两个所述圆形补锂膜块之间的最短距离为10μm～1000μm，可选的为10μm～500μm，可选的为100μm～500μm。The lithium supplement negative pole piece according to claim 7, wherein the shortest distance between two adjacent circular lithium supplement membrane blocks is 10 μm to 1000 μm, optionally 10 μm to 500 μm, and optionally 100 μm ~500μm.
根据权利要求1-8任一项所述的补锂负极极片，其中，所述补锂膜块的原料选自锂粉、锂锭和锂片中的一种或多种；8. The lithium-supplementing negative pole piece according to any one of claims 1-8, wherein the raw material of the lithium-supplementing membrane block is selected from one or more of lithium powder, lithium ingot and lithium sheet;

可选的，所述补锂膜块的原料选自锂粉，其中，所述补锂膜块为由锂粉浆料涂布，并经干燥而成的，所述锂粉浆料包含锂粉和有机溶剂。Optionally, the raw material of the lithium supplementary film block is selected from lithium powder, wherein the lithium supplementary film block is formed by coating and drying a lithium powder slurry, and the lithium powder slurry contains lithium powder And organic solvents.
根据权利要求1-9任一项所述的补锂负极极片，其中，所述补锂氧化层包括选自单质锂、氧化锂、氮化锂、氟化锂、氢氧化锂、碳酸锂、碳化锂、锂硅合金中的一种或多种。The lithium-supplementing negative pole piece according to any one of claims 1-9, wherein the lithium-supplementing oxide layer comprises elementary lithium, lithium oxide, lithium nitride, lithium fluoride, lithium hydroxide, lithium carbonate, One or more of lithium carbide and lithium silicon alloy.
一种补锂负极极片的制备方法，包括以下步骤：A method for preparing a lithium-supplemented negative pole piece includes the following steps:

(a)提供待补锂的负极极片，所述待补锂的负极极片包括负极集流体以及设置在所述负极集流体至少一个表面上的负极活性材料层；(a) Providing a negative pole piece for lithium to be supplemented, which comprises a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector;

(b)在所述负极活性材料层远离所述负极集流体的表面上形成呈阵列排布的若干补锂膜块，得到补锂负极极片；(b) forming a plurality of lithium supplement film blocks arranged in an array on the surface of the negative electrode active material layer away from the negative electrode current collector to obtain a lithium supplement negative pole piece;

其中，所述补锂负极极片化成后，若干补锂膜块残留的补锂氧化层在负极活性材料层上的投影面积之和S ₁与负极活性材料层的面积S ₀的比值S ₁/S ₀为30％～99％。 Wherein, after the formation of the lithium-supplementing negative electrode, the sum of the projected areas of the lithium-supplementing oxide layers remaining on the negative electrode active material layer S ₁ and the area S ₀ of the negative electrode active material layer S ₁ / S ₀ is 30% to 99%.
根据权利要求11所述的方法，其中，步骤(b)包括：The method according to claim 11, wherein step (b) comprises:

将锂粉分散于有机溶剂中，得到补锂浆料；Disperse the lithium powder in an organic solvent to obtain a lithium supplement slurry;

所述负极活性材料层的远离所述负极集流体的表面区分为呈阵列排布的若干补锂区域，将所述补锂浆料涂布于所述若干补锂区域，经干燥，形成阵列排布的若干补锂膜块。The surface of the negative electrode active material layer away from the negative electrode current collector is divided into several lithium supplement areas arranged in an array, and the lithium supplement slurry is applied to the several lithium supplement areas and dried to form an array array Several lithium replenishment film blocks of cloth
根据权利要求12所述的方法，其中，通过丝网印刷工艺将所述补锂浆料涂布于所述若干补锂区域。The method according to claim 12, wherein the lithium supplementation paste is applied to the plurality of lithium supplementation areas by a screen printing process.
一种锂离子电池，包括正极极片、负极极片、间隔于所述正极极片和所述负极极片之间的隔离膜、电解液，其中，所述负极极片采用根据权利要求1-10中任一项所述的补锂负极极片或根据权利要求11-13中任一项所述制备方法得到的补锂负极极片。A lithium ion battery, comprising a positive pole piece, a negative pole piece, a separator separated between the positive pole piece and the negative pole piece, and an electrolyte, wherein the negative pole piece adopts The lithium-supplemented negative pole piece according to any one of 10 or the lithium-supplemented negative pole piece obtained by the preparation method according to any one of claims 11-13.
根据权利要求14所述的锂离子电池，其中，所述正极极片、所述负极极片和所述隔离膜组成卷绕式电芯，所述卷绕式电芯化成后的拐角间隙为0.1μm～50μm，可选的为3μm～30μm，可选的为1.5μm～6μm。The lithium ion battery according to claim 14, wherein the positive pole piece, the negative pole piece, and the separator constitute a wound cell, and the corner gap after the wound cell is formed is 0.1 μm～50μm, optional 3μm～30μm, optional 1.5μm～6μm.
根据权利要求14所述的锂离子电池，其中，所述正极极片、所述负极极片和所述隔离膜组成卷绕式电芯，所述卷绕式电芯化成后，所述负极极片与所述隔离膜之间的间隙为0.1μm～50μm，可选的为3μm～30μm，可选的为1.5μm～6μm。The lithium ion battery according to claim 14, wherein the positive pole piece, the negative pole piece and the separator constitute a wound cell, and after the wound cell is formed, the negative electrode The gap between the sheet and the isolation membrane is 0.1 μm-50 μm, optionally 3 μm-30 μm, and optionally 1.5 μm-6 μm.
一种电池模块，包括根据权利要求14-16任一项所述的锂离子电池。A battery module comprising the lithium ion battery according to any one of claims 14-16.
一种电池包，包括根据权利要求17所述的电池模块。A battery pack comprising the battery module according to claim 17.
一种装置，包括根据权利要求14-16任一项所述的锂离子电池、根据权利要求17所述的电池模块、或根据权利要求18所述的电池包。A device comprising the lithium ion battery according to any one of claims 14-16, the battery module according to claim 17, or the battery pack according to claim 18.