Lithium battery capable of prolonging cycle life of electrode assembly

Abstract

The utility model relates to a lithium battery capable of prolonging the cycle life of an electrode assembly in the technical field of lithium batteries, which comprises a shell filled with electrolyte; the electrode assembly is arranged in the shell; the top cover assembly covers the open end of the shell; the slow-release layer is arranged in the shell and located between the electrode assembly and the shell, the slow-release layer is provided with pore structures for containing electrolyte, at least part of the pore structures are connected through micro-pipelines, and the diameter of the micro-pipelines is gradually reduced from the top of the slow-release layer to the bottom of the slow-release layer. By adopting the design of the slow-release layer, the electrolyte can be released when the electrode assembly expands, so that the electrolyte is prevented from being accumulated, and the cycle life of the battery is prolonged. The slow-release layer occupies a certain space, so that the expansion and contraction space of the pole piece in the charging and discharging process is effectively reserved, the damping effect is achieved, and the electrode assembly is protected. The slow-release layer has electronic insulativity, prevents short circuit of the electrode assembly, and improves the safety of the battery.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery technical field, especially in lithium battery of can improve electrode assembly cycle life. BACKGROUND

[0002] With the development of lithium battery technology, the safety and cycle life of electrode assembly in lithium battery are more and more concerned by people, and most electrode assemblies on the current market adopt aluminum shell as protective structure material, because aluminum shell has excellent characteristics such as high specific strength, specific modulus, fracture toughness, fatigue strength and corrosion resistance stability, among which, square aluminum shell electrode assembly is especially favored. The main reasons are as follows: first, the monomer electrode assembly capacity is large. Secondly, compared with square soft package electrode assembly, square aluminum shell electrode assembly has significant improvement in internal protection. In addition, square aluminum shell electrode assembly has superior heat dissipation performance, simple composition mode and easy design, and the system energy density is relatively high, which is also convenient for setting explosion-proof valve, thereby improving the overall safety.

[0003] However, the adoption of square aluminum shell electrode assembly by lithium battery improves the safety, but does not improve the cycle life of electrode assembly, and the electrolyte is continuously consumed in the cycle process of lithium battery, and under the influence of gravity, the electrolyte above the battery is consumed first, leading to insufficient impregnation of pole piece, and further producing lithium dendrite, which seriously affects the cycle life of electrode assembly.

[0004] Therefore, the market urgently needs a new type of lithium battery, which meets the demand of improving the cycle life of electrode assembly on the basis of adopting square aluminum shell electrode assembly. UTILITY MODEL CONTENT

[0005] In order to solve the above technical problems, the utility model provides a lithium battery capable of improving the cycle life of electrode assembly to improve the cycle life of electrode assembly in lithium battery, and the technical scheme of the utility model is as follows:

[0006] A lithium battery capable of improving the cycle life of electrode assembly, comprising:

[0007] A shell filled with electrolyte inside;

[0008] An electrode assembly arranged in the shell;

[0009] A top cover assembly arranged at the open end of the shell;

[0010] A slow-release layer arranged between the electrode assembly and the shell in the shell, the slow-release layer is provided with pore structure for accommodating electrolyte, at least part of the pore structures are connected by micro-pipe, and the diameter of the micro-pipe gradually decreases from the top of the slow-release layer to the bottom of the slow-release layer.

[0011] Preferably, the porosity of the slow-release layer gradually increases from the bottom of the slow-release layer to the top of the slow-release layer.

[0012] Preferably, the porosity of the slow-release layer gradually increases from the inner wall of the shell to the electrode assembly.

[0013] Preferably, the diameter of the micro-pipe gradually increases from the inner wall of the shell to the electrode assembly.

[0014] Preferably, the porosity of the slow-release layer is 10% to 95%.

[0015] Preferably, the diameter of the micro-pipe is less than or equal to the diameter of the pore structure connected thereto.

[0016] Preferably, the slow-release layer is a single-layer structure or a laminated structure composed of at least one of a polyethylene layer, a polypropylene layer, a polyethylene terephthalate layer, an aerogel layer, a foamed material layer, and a silicone rubber layer.

[0017] Preferably, the slow-release layer is bonded to the inner wall of the shell.

[0018] Preferably, the electrode group comprises a plurality of positive electrode sheets and negative electrode sheets alternately stacked, and the sidewall formed by the stacking of the positive electrode sheets and the negative electrode sheets is in contact with the slow-release layer.

[0019] Preferably, a gap for accommodation is provided between the top of the slow-release layer and the opening position of the top of the shell.

[0020] The advantages of the utility model are as follows:

[0021] 1. The slow-release layer has a pore structure for containing electrolyte, and the diameter of the micro-pipe connecting the pores gradually increases from the bottom to the top of the slow-release layer. The smaller end of the micro-pipe has a certain adsorption force on the electrolyte, making it easier for the electrolyte to enter the micro-pipe and then enter the other end of the pore. When the electrolyte is squeezed, it is more inclined to flow to the top of the slow-release layer. This can gradually release the electrolyte during the lithium battery cycle, solve the problem of lithium dendrite caused by insufficient electrolyte above the battery, maintain the stability of the electrode assembly, reduce the degradation of the electrode material, and thus prolong the service life of the lithium battery.

[0022] 2. The design of the slow-release layer optimizes the internal structure of the lithium battery. Since the slow-release layer has a certain elasticity and occupies a certain space, it can reduce the group margin to a certain extent, effectively reserve the space for the expansion and contraction of the electrode sheet during charging and discharging, and play a shock-absorbing role to protect the electrode assembly. This can better cope with the internal pressure changes of the lithium battery and prevent the lithium battery from swelling or deforming. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only represent one embodiment of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Wherein the same parts are indicated by the same reference numerals. It should be noted that the words "front", "back", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "bottom" and "top", "inner" and "outer" refer to the directions towards or away from the geometric center of a particular part.

[0025] Figure 1 It is an internal schematic view of the embodiment 1 of the present application. It should be noted that the electrode assembly shown in the figure is also provided with a buffer layer on the front and back two surfaces, and in addition, the figure is designated as the abstract drawing;

[0026] Figure 2 It is an internal schematic view of the embodiment 2 of the present application. It should be noted that the top cover assembly is arranged on one side of the electrode assembly in the third direction shown in the figure, and the third direction is perpendicular to the first direction and the second direction;

[0027] Figure 3 It is an internal schematic view of the embodiment 3 of the present application. It should be noted that the electrode assembly shown in the figure is also provided with a buffer layer on the front and back two surfaces;

[0028] Figure 4 It is a three-dimensional structure schematic view of the embodiment 3 of the present application. It should be noted that in order to reflect the positional relationship between the electrode assembly and the buffer layer, Figure 4 The top cover assembly is not drawn in the figure, and in addition, Figure 4 The x, y and z in the figure respectively represent the x-axis direction, the y-axis direction and the z-axis direction.

[0029] In the above drawings, the meanings of the reference numerals are as follows:

[0030] 1. Electrode assembly;

[0031] 2. Buffer layer;

[0032] 3. Top cover assembly;

[0033] 4. Shell. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described clearly and completely below in connection with the embodiments of the present application and the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specific embodiments are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0036] In the description of the specific embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0037] In the present application, "embodiments" means that the specific features, structures or properties described in connection with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments.

[0038] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents a "or" relationship between the front and rear associated objects.

[0039] Throughout this utility, numerical values represent approximate measurements or limits to encompass minor deviations from a given value and embodiments having about the referenced value and embodiments having the referenced exact value. Except in the Examples provided at the end of the detailed description, all numerical values of parameters such as amounts or conditions are to be understood as modified in all instances by the term "about" whether or not "about" actually appears before the numerical value so modified. "About" indicates that the stated numerical value allows some slight imprecision in the value with some degree of error in the range of values that could be expected to occur due to the normal variability of measurements, typically measured, and the application of the numerical values. For example, "about" can include a variation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some aspects, optionally less than or equal to 0.1%.

[0040] In addition, the disclosure of ranges includes all values and further divisions of ranges within the entire range, including the endpoints and subranges given for the ranges.

[0041] With the development of lithium battery technology, the safety and cycle life of the electrode assembly in the lithium battery are increasingly concerned, and most of the electrode assemblies on the current market adopt aluminum shell as the protective structure material, because the aluminum shell has excellent characteristics such as high specific strength, specific modulus, fracture toughness, fatigue strength and corrosion resistance stability, among which, the square aluminum shell electrode assembly is particularly favored. The main reasons are as follows: first, the single electrode assembly has large capacity. Second, compared with the square soft package electrode assembly, the square aluminum shell electrode assembly has significant improvement in internal protection. In addition, the square aluminum shell electrode assembly has superior heat dissipation performance, simple composition and easy design, relatively high system energy density, and is convenient for setting the explosion-proof valve, thereby improving the overall safety.

[0042] However, the lithium battery adopts the square aluminum shell electrode assembly to improve the safety, but does not improve the cycle life of the electrode assembly, because the electrolyte of the lithium battery is consumed continuously in the cycle process, and under the influence of gravity, the electrolyte above the battery is consumed first, which leads to insufficient impregnation of the pole piece, and further generates lithium dendrites, which seriously affects the cycle life of the electrode assembly, therefore, the market urgently needs a new type of lithium battery, which meets the demand of improving the cycle life of the electrode assembly on the basis of adopting the square aluminum shell electrode assembly.

[0043] In order to solve the above technical problems, the utility model provides a lithium battery capable of improving the cycle life of electrode assembly to improve the cycle life of electrode assembly in lithium battery.

[0044] The shell is filled with electrolyte;

[0045] The electrode assembly is arranged in the shell;

[0046] The top cover assembly is arranged on the open end of the shell;

[0047] The slow-release layer is arranged between the electrode assembly and the shell in the shell, the slow-release layer is provided with pore structure containing electrolyte, at least part of the pore structure is connected through micro-pipeline, and the diameter of the micro-pipeline gradually decreases from the top of the slow-release layer to the bottom of the slow-release layer.

[0048] In the utility model, one end of the micro-pipeline with small caliber has certain adsorption force to electrolyte, so that the electrolyte is more easily entered into the micro-pipeline and then entered into the other end pore through the micro-pipeline, and then the electrolyte is more inclined to flow to the top of the slow-release layer when being extruded, the electrolyte can be gradually released in the cycle process of the lithium battery, the problem of lithium dendrite caused by insufficient electrolyte above the battery is solved, the stability of the electrode assembly is maintained, the deterioration of the electrode material is reduced, and the service life of the lithium battery is prolonged.

[0049] In some embodiments, the porosity of the slow-release layer gradually increases from the bottom of the slow-release layer to the top of the slow-release layer.

[0050] Since the greater the porosity is, the easier the liquid is absorbed, and the smaller the porosity is, the less the liquid is absorbed, the porosity of the slow-release layer is designed to gradually increase from the bottom end to the top end, so that the liquid absorption capacity of the slow-release layer gradually increases from bottom to top. The electrolyte in the battery is easily accumulated at the bottom of the battery due to gravity, the liquid absorption capacity of the bottom of the slow-release layer is poor, and the liquid absorption capacity of the top is strong, so that the distribution of electrolyte in the battery monomer is balanced, the wetting effect of the electrode assembly is improved, the lithium precipitation on the surface of the electrode assembly is reduced, and the cycle life of the battery is further improved.

[0051] In some embodiments, the porosity of the slow-release layer gradually increases from the bottom of the slow-release layer to the top of the slow-release layer.

[0052] The porosity of the slow-release layer is designed in the above form, which makes the surface of the slow-release layer more easily release the electrolyte when being pressed, avoids the electrolyte from being deposited on the side of the slow-release layer close to the shell, and helps the slow-release layer to fully release the electrolyte.

[0053] In some embodiments, the diameter of the micro-pipe gradually increases from the inner wall of the shell to the electrode assembly.

[0054] Due to the different diameters of the two ends of the micro-pipe, the smaller end has a certain adsorption capacity for the electrolyte, which makes the electrolyte more easily enter the micro-pipe. By setting the diameter of the micro-pipe to gradually increase from the inner wall of the shell to the electrode assembly, the electrolyte on the side of the slow-release layer close to the shell is more easily released through the micro-pipe to the side close to the electrode assembly after the slow-release layer is pressed, avoiding the electrolyte from being deposited on the slow-release layer and unable to be released.

[0055] In some embodiments, the porosity of the slow-release layer is 10% to 95%.

[0056] By designing the porosity of the slow-release layer in the above range, the problem of lithium dendrite caused by insufficient electrolyte above the battery can be solved under the premise of ensuring the buffering effect. In addition, the porosity of the slow-release layer gradually changes, and the maximum porosity cannot exceed 95% and the minimum porosity cannot be less than 10%, so as to ensure the effect of the slow-release layer.

[0057] In some embodiments, the diameter of the micro-pipe is less than or equal to the diameter of the pore structure connected thereto.

[0058] In some embodiments, the slow-release layer is a single-layer structure or a laminated structure composed of at least one of a polyethylene layer, a polypropylene layer, a polyethylene terephthalate layer, an aerogel layer, a foamed material layer, and a silicone rubber layer.

[0059] In specific applications, the slow-release layer can select one of the above as a single-layer structure, can select one of the above to construct a laminated structure, or can select two or more of the above as a composite laminate. The above selection can be selected according to the actual situation. The present application does not make any limitation on this.

[0060] In some embodiments, the slow-release layer is bonded to the inner wall of the shell.

[0061] The slow-release layer is bonded to the inner wall of the shell, which makes the slow-release layer not loose the structure fixed by the expansion of the electrode assembly in the cycle process. In addition, the porosity of the side of the slow-release layer close to the shell is small, which makes the contact area between this side and the shell large, and can further strengthen the firmness of the bonding with the inside of the shell.

[0062] The electrode assembly can be alternatively configured as a jelly-roll assembly and a stack assembly. The stack assembly is configured by stacking a plurality of positive and negative electrode sheets alternately, and the jelly-roll assembly is configured by winding the positive and negative electrode sheets into a cylindrical or other shape.

[0063] In some embodiments, the electrode assembly is a jelly-roll assembly, and the strip-shaped positive and negative electrode sheets are wound to form a cylindrical electrode assembly. In this case, the outer surface of the cylinder can be used as a side wall to contact the slow-release layer.

[0064] In some embodiments, the electrode assembly is a stack assembly, and the sheet-shaped positive and negative electrode sheets are stacked to form a cubic electrode assembly. In this case, the four side walls of the cubic electrode assembly can be used to contact the slow-release layer. The side walls formed by stacking the positive and negative electrode sheets can contact the slow-release layer, so that the electrolyte released from the slow-release layer can infiltrate the side walls formed by stacking the positive and negative electrode sheets, and then enter the positive and negative electrode sheets, thereby achieving better infiltration of the electrode sheets.

[0065] In some embodiments, a gap is provided between the top of the slow-release layer and the opening of the top of the shell for positioning. The gap serves as a reserved area for welding the cover plate.

[0066] The embodiments of the present application will be described in more detail by the following examples. It should be noted that the embodiments of the present application are not limited to these examples.

[0067] Example 1

[0068] In a specific embodiment 1, as shown in FIG. 1, a lithium battery capable of improving the cycle life of an electrode assembly includes an electrode assembly 1, a slow-release layer 2, a top cover assembly 3, and a shell 4. Figure 1

[0069] In this embodiment, the lithium battery is kept upright during use, so that the electrode assembly 1 is placed vertically inside the shell 4, and the slow-release layer 2 is arranged on the side of the electrode assembly 1 and adhered to the outer shell 4. In this way, the slow-release layer 2 is fixed to the inner wall of the shell 4 and will not be loosened due to the expansion of the electrode assembly 1. The slow-release layer 2 is arranged on the four side walls of the inner wall of the shell 4 to form a buffer protection layer around the bare electrode assembly 1. The slow-release layer 2 occupies a certain space, which can reduce the group margin to some extent and effectively reserve the space for the expansion and contraction of the electrode sheets during charging and discharging, thereby playing a shock-absorbing role and protecting the electrode assembly 1.

[0070] In addition, the slow-release layer 2 has a pore structure for containing electrolyte, and at least part of the pore structures are connected by micro-pipes.

[0071] ​The diameter of the microchannel gradually decreases from the top to the bottom of the sustained-release layer 2, and gradually increases from the inner wall of the housing 4 toward the electrode assembly 1. The smaller end of the microchannel has a certain adsorption force on the electrolyte, making it easier for the electrolyte to enter the microchannel and enter the pores at the other end through the microchannel. As a result, when squeezed, the electrolyte is more likely to flow from the bottom to the top of the sustained-release layer 2 and from the interior of the housing 4 toward the electrode assembly 1.

[0072] The pore structure of the slow-release layer 2 increases in the direction from the shell 4 to the electrode assembly 1, and increases in the direction from the bottom of the shell 4 to the top cover assembly 3. The greater the porosity, the easier it is to absorb liquid, and the smaller the porosity, the less likely it is to absorb liquid. The porosity of the slow-release layer 2 is designed to gradually increase from the bottom to the top of the slow-release layer 2, so that the liquid absorption capacity of the slow-release layer 2 can gradually become stronger from bottom to top, so that the flow direction of the electrolyte in the slow-release layer 2 is from bottom to top, preventing the electrolyte in the battery from accumulating at the bottom of the battery due to gravity. In addition, when the slow-release layer 2 is squeezed, the closer it is to the electrode assembly 1, the stronger the liquid absorption energy of the slow-release layer 2, so that the electrolyte can more easily move from the side of the shell 4 to the direction of the electrode assembly 1, avoiding the electrolyte from being deposited in the slow-release layer 2 and unable to be released.

[0073] Example 2

[0074] In a specific embodiment 2, Figure 2 As shown, a lithium battery capable of improving the cycle life of an electrode assembly includes an electrode assembly 1, a sustained-release layer 2, a top cover assembly and a shell 4, wherein the sustained-release layer 2 is arranged between the electrode assembly 1 and the shell 4.

[0075] Unlike Example 1, in this embodiment, the lithium battery is placed horizontally during use. The electrode assembly 1 of the battery is horizontally disposed within the housing 4. The sustained-release layer 2 wraps around the left, right, top, and bottom sides of the electrode assembly 1, and a top cover assembly is disposed on the front side of the electrode assembly 1.

[0076] The terms "front", "back", "left", "right", "up", and "down" in this embodiment only refer to Figure 2 direction.

[0077] Among them, the sustained-release layer located on the right side of the electrode assembly 1 has: the porosity increases in the first direction and decreases in the second direction; the diameter of the micro-channel increases in the first direction and decreases in the second direction.

[0078] The sustained-release layer located on the left side of the electrode assembly 1 has a porosity that increases in the first direction and in the second direction; and a diameter of the microchannel that increases in the first direction and in the second direction.

[0079] The sustained-release layer located on the upper side of the electrode assembly 1 has a porosity that decreases in the first direction and remains unchanged in the second direction; and a diameter of the microchannels that decreases in the first direction and remains unchanged in the second direction.

[0080] The sustained-release layer located on the lower side of the electrode assembly 1 has a porosity that increases in the first direction and remains unchanged in the second direction; and a diameter of the microchannel increases in the first direction and remains unchanged in the second direction.

[0081] The above design ensures that the electrolyte in each sustained-release layer 2 tends to flow from the inner wall of the housing 4 toward the electrode assembly 1 when squeezed, and the electrolyte in the sustained-release layer 2 on the left, right, and bottom sides tends to flow upward when squeezed. The electrolyte in the sustained-release layer 2 on the top side tends to flow downward when squeezed.

[0082] Example 3

[0083] In a specific embodiment 3, Figure 3 As shown, a lithium battery capable of improving the cycle life of an electrode assembly includes an electrode assembly 1, a sustained-release layer 2, a top cover assembly 3 and a shell 4.

[0084] Different from the embodiment 1, in this embodiment, the long columnar cubic electrode assembly 1 is placed sideways in the housing 4, and the top cover assembly 3 is arranged on the side of the housing 4 (such as Figure 3 The sustained-release layer 2 is wrapped as shown in the right side of the housing 4. Figure 3 The front side, rear side, top side and bottom side of the electrode assembly 1 are shown.

[0085] The terms "front", "back", "upper" and "lower" in this embodiment only represent Figure 3 direction.

[0086] like Figure 4 As shown, the sustained-release layer on the underside of the electrode assembly 1 has a porosity that is constant in the x-axis, increases in the y-axis, and remains constant in the z-axis. The microchannels are constant in the x-axis, increase in the y-axis, and remain constant in the z-axis. This design allows the electrolyte in the sustained-release layer to flow upward when squeezed.

[0087] like Figure 4 As shown, the porosity of the sustained-release layer located on the upper side of the electrode assembly 1 is constant in the x-axis direction, decreases in the y-axis direction, and remains constant in the z-axis direction. This design makes the electrolyte in the sustained-release layer more inclined to flow downward when squeezed.

[0088] like Figure 4As shown, the sustained-release layer located on the front side of the electrode assembly 1 has a constant porosity in the x-axis direction, increasing in the y-axis direction, and increasing in the z-axis direction; the microchannels remain constant in the x-axis direction, increasing in the y-axis direction, and increasing in the z-axis direction. This design allows the electrolyte in the sustained-release layer to flow upward when squeezed, while also tending to flow from the inner wall of the housing 4 toward the electrode assembly 1.

[0089] like Figure 4 As shown, the sustained-release layer located on the rear side of the electrode assembly 1 has a porosity that remains constant in the x-axis, increases in the y-axis, and decreases in the z-axis. The microchannels remain constant in the x-axis, increase in the y-axis, and decrease in the z-axis. This design allows the electrolyte in the sustained-release layer to flow upward when squeezed, while also tending to flow from the inner wall of the housing 4 toward the electrode assembly 1.

[0090] It should be pointed out that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lithium battery capable of improving the cycle life of an electrode assembly, characterized in that: The application relates to a battery, comprising: a shell filled with electrolyte; an electrode assembly arranged in the shell; a top cover assembly covering an open end of the shell; a slow-release layer arranged in the shell between the electrode assembly and the shell, the slow-release layer being provided with a pore structure containing electrolyte, at least part of the pore structures being connected by micro-pipes, the diameter of the micro-pipes gradually decreasing from the top of the slow-release layer to the bottom of the slow-release layer.

2. The lithium battery with improved cycle life of the electrode assembly according to claim 1, wherein The porosity of the slow-release layer gradually increases from the bottom of the slow-release layer to the top of the slow-release layer.

3. The lithium battery with improved cycle life of the electrode assembly according to claim 1, wherein The porosity of the slow-release layer gradually increases from the inner wall of the shell to the electrode assembly.

4. The lithium battery capable of improving the cycle life of the electrode assembly according to claim 1, wherein: The diameter of the micro-pipes gradually increases from the inner wall of the shell to the electrode assembly.

5. The lithium battery with improved cycle life of the electrode assembly according to claim 1, wherein The porosity of the slow-release layer is 10%-95%.

6. The lithium battery with improved cycle life of the electrode assembly according to claim 1, wherein The diameter of the micro-pipes is equal to or smaller than the diameter of the pore structure connected thereto.

7. The lithium battery with improved cycle life of the electrode assembly according to claim 1, wherein The slow-release layer is a single-layer structure or a laminated structure composed of at least one of a polyethylene layer, a polypropylene layer, a polyethylene terephthalate layer, an aerogel layer, a foamed material layer and a silicone rubber layer.

8. The lithium battery with improved cycle life of the electrode assembly according to any one of claims 1 to 7, wherein The slow-release layer is bonded to the inner wall of the shell.

9. The lithium battery with improved cycle life of the electrode assembly according to any one of claims 1 to 7, wherein The electrode assembly comprises a plurality of positive electrode sheets and negative electrode sheets alternately stacked, and the side wall of the electrode assembly formed by the positive electrode sheets and the negative electrode sheets is in contact with the slow-release layer.

10. The lithium battery with improved cycle life of the electrode assembly according to any one of claims 1 to 7, wherein A gap is arranged between the top of the slow-release layer and the opening position of the top of the shell.

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