A battery, a battery pack and an electrical device

Abstract

This invention provides a battery, a battery pack, and an electrical device. The battery includes a casing, a core assembly, an electrolyte, and several liquid-conducting cores. The casing has opposing top and bottom ends. The core assembly, liquid-conducting cores, and electrolyte are all disposed within the casing. The electrolyte is immersed in the core assembly and the liquid-conducting cores. The core assembly includes at least one core body. The liquid-conducting cores are disposed between the core assembly and the casing, extending from the bottom end to the top end. The outer surface of the liquid-conducting core is in contact with the outer wall surface of at least one core body. This invention solves the problems of dry edges and insufficient wetting of the core electrode sheets, effectively improving battery cycle life.

Description

Technical Field

[0001] This invention belongs to the field of battery technology and relates to a battery, a battery pack, and an electrical device. Background Technology

[0002] Currently, uneven electrolyte wetting is one of the reasons for accelerated battery aging. During battery use, the electrolyte penetrates into the cell and reacts chemically with the positive and negative electrode materials, thus forming a current in the circuit. During long-term charging and discharging, the electrolyte is continuously reduced and decomposed at the negative electrode to form an SEI film, which leads to a reduction in the total amount of electrolyte. Furthermore, the outermost edges of the electrode or the areas with the longest penetration paths dry out, and the unwetted electrode areas cannot participate in the electrochemical reaction, resulting in a decrease in battery capacity. The increased resistance in areas lacking electrolyte makes them prone to localized overcharging or over-discharging, accelerating material structure damage and degradation, further reducing battery cycle life. In addition, during battery charging, due to insufficient electrolyte at the negative electrode, lithium ions cannot properly embed into the graphite layer, leading to the formation of lithium dendrites on the negative electrode surface. These dendrites grow continuously, piercing the separator, causing a direct short circuit between the positive and negative electrodes, triggering thermal runaway, and resulting in battery fire or explosion.

[0003] Existing technologies improve electrolyte wetting by increasing the amount of electrolyte injected or extending the wetting time. However, the more electrolyte injected, the less space is left for active materials such as positive and negative electrode materials, which affects the volumetric energy density and gravimetric energy density of the battery. Furthermore, excessive electrolyte injection can lead to gas expansion, increased internal resistance, and higher costs, which in turn accelerates battery aging and shortens battery cycle life. On the other hand, excessively long electrolyte wetting time reduces production efficiency, increases equipment costs, and may even introduce quality risks.

[0004] Therefore, how to achieve uniform and sufficient wetting without sacrificing energy density and cost has become an urgent problem to be solved. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a battery, battery pack and power device that utilizes the ineffective gap between the core and the outer shell, without changing the original winding and casing process, and solves the problem of dry and insufficient wetting of the core electrode edges.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a battery comprising a housing, a core assembly, an electrolyte, and a plurality of liquid-conducting cores. The housing has opposing top and bottom ends. The core assembly, liquid-conducting cores, and electrolyte are all disposed within the housing. The electrolyte is immersed in the core assembly and the liquid-conducting cores. The core assembly includes at least one core body. The liquid-conducting cores are disposed between the core assembly and the housing, extending from the bottom end to the top end, and the outer surface of the liquid-conducting cores is in contact with the outer wall surface of at least one core body.

[0007] As a preferred embodiment of the present invention, the liquid guiding core has a strip-shaped structure.

[0008] In one embodiment of the present invention, the end of the liquid guiding core near the top is not lower than the end face of the core body, and the end of the liquid guiding core near the bottom extends into the electrolyte located at the bottom of the housing.

[0009] In this invention, the top of the liquid-conducting core is not lower than the end face of the core body, and its bottom is close to the bottom of the shell, so as to directionally transport the electrolyte concentrated in the lower part of the shell cavity to the edge of the core electrode near the top for wetting, so as to replenish the electrolyte consumed at the edge.

[0010] This invention has high space utilization, simple assembly, and effectively improves battery energy density, making it suitable for mass production.

[0011] As a preferred embodiment of the present invention, the battery further includes an insulating layer, which wraps around the side and bottom surfaces of the winding core and the liquid guiding core to form an integral structure.

[0012] This invention utilizes an insulating layer to isolate the core assembly from the housing, preventing internal short circuits, while also providing support for the liquid guiding core, restricting its movement and affecting the directional delivery of electrolyte.

[0013] As a preferred embodiment of the present invention, the liquid guiding core has a porous capillary structure.

[0014] The liquid-conducting core of this invention achieves directional delivery of electrolyte through capillary liquid conduction, so that electrolyte continuously accumulates at the edge of the core electrode near the top, replenishing electrolyte consumption, preventing the electrode edge from drying out, reducing the amount of liquid injected, improving wetting efficiency, and also reducing the risk of lithium plating and gas expansion.

[0015] As a preferred embodiment of the present invention, the porosity of the liquid guiding core near the bottom end is less than that of the liquid guiding core near the top end, and the pore size of the porous capillary structure of the liquid guiding core near the bottom end is less than that of the porous capillary structure of the liquid guiding core near the top end.

[0016] In this invention, the portion of the liquid-conducting core near the bottom has low porosity and small micropore diameter, while the portion near the top has high porosity and large micropore diameter. The electrolyte is continuously transported upward from the bottom by capillary force to fully wet the top edge of the coiled electrode sheet and improve battery efficiency.

[0017] As a preferred embodiment of the present invention, the porosity of the liquid guiding core increases in a gradient from the end near the bottom to the end near the top.

[0018] In this invention, the porosity of the liquid-conducting core increases, which allows the electrolyte to continuously and stably accumulate at the edge of the core body near the top, fully wetting the edge of the electrode sheet, and the wetting rate is controllable.

[0019] In one embodiment, the porosity of the fluid guiding core is 5% to 80%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] As a preferred embodiment of the present invention, the material of the liquid guiding core includes at least one of polymer porous body, ceramic porous body, glass fiber paper or foam metal.

[0021] In one embodiment of the present invention, the cross-section of the fluid guiding core is at least one of a circular, polygonal, elliptical, or irregular shape.

[0022] In one embodiment of the present invention, the liquid guiding core is a monolithic homogeneous structure or a composite structure consisting of an inner core and a covering layer surrounding the outer periphery of the inner core.

[0023] In one embodiment of the present invention, the liquid guiding core is an integral single-material component, or a spliced ​​component formed by connecting at least two different porous materials end to end along the axial direction.

[0024] As a preferred embodiment of the present invention, the total volume of the core assembly is 90% to 98% of the volume of the housing, for example, it can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97% or 98%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] This invention maximizes the utilization of the casing space and effectively improves the battery energy density.

[0026] In one embodiment of the present invention, the volume of the electrolyte is 20% to 45% of the volume of the shell, for example, it can be 20%, 25%, 30%, 35%, 40% or 45%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] In a second aspect, the present invention provides a battery pack comprising the battery described in the first aspect.

[0028] Thirdly, the present invention provides an electrical device, wherein the electrical device comprises the battery pack described in the second aspect.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention fills the gap between the core and the shell with a liquid-conducting core. The structure is simple and does not require any changes to the original cell structure and production process. It significantly improves the electrolyte wetting effect near the top edge of the core electrode, prevents drying, improves battery cycle life, and reduces the risk of lithium plating. The overall space utilization is high, the assembly is simple, and sufficient wetting can be achieved without excessive liquid injection. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the square-shaped wound battery provided in Embodiment 1 of the present invention.

[0031] Wherein, 1-shell; 2-core body; 3-liquid guiding core; 4-insulating layer; X-first direction; Y-second direction; Z-third direction. Detailed Implementation

[0032] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more.

[0033] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B.

[0035] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention.

[0036] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] During the cycling process, existing battery cells are prone to problems such as rapid electrolyte consumption, insufficient wetting, lack of timely replenishment, and drying at the top edge of the electrode, which leads to lithium plating at the electrode edge and a decrease in cycle life.

[0038] In one specific embodiment, the present invention provides a battery comprising a housing, a core assembly, an electrolyte, and a plurality of liquid-conducting cores. The housing has opposing top and bottom ends. The core assembly, liquid-conducting cores, and electrolyte are all disposed within the housing. The electrolyte is immersed in the core assembly and the liquid-conducting cores. The core assembly includes at least one core body. The liquid-conducting cores are disposed between the core assembly and the housing, extending from the bottom end to the top end. The outer surface of the liquid-conducting core is in contact with the outer wall surface of at least one core body, effectively utilizing the ineffective gap between the core and the housing.

[0039] The housing can be square or cylindrical, and its volume can be adapted to meet actual capacity requirements and application scenarios; this invention does not impose specific limitations on this. A square housing is preferred due to its high space utilization and high energy density. The housing is primarily made of metal, including but not limited to steel or aluminum. An injection hole is provided on the housing to inject electrolyte into the housing after assembling the core assembly.

[0040] The number of core bodies in the core assembly can be 1, 2, 3, 4, 5, 8, 10, 12, 15, 18, 20, 30, etc., but is not limited to the listed values. Those skilled in the art can adjust the number according to actual capacity requirements. The core body is a structure formed by stacking and winding positive electrode sheets, separators, and negative electrode sheets in sequence. The cross-section of the core body is racetrack-shaped; one winding creates two straight sections and two bent sections. The two straight sections are parallel, and the bent sections have a semi-circular structure, connecting the straight sections on both sides. The arc transition portion of the bent section is called the R-angle. The radius of the bent section gradually increases from the inner to the outer circle. Positive and negative tabs are respectively provided on the positive and negative electrode sheets, extending from near the top of the casing to connect internal and external currents.

[0041] The end of the liquid guiding core near the top is not lower than the end face of the core body, and the end of the liquid guiding core near the bottom extends into the electrolyte located at the bottom of the housing, which is used to transport the electrolyte near the bottom of the housing to the top edge of the electrode of the core body, so that the electrolyte is enriched and avoids drying.

[0042] It should be noted that, in this invention, the end face of the core body refers to the top end face of the core body, that is, the large surface of the core body near the top of the housing, excluding the tab structure, and "not lower than" means that the end of the liquid guide wick near the top is flush with or higher than the aforementioned end face. Practically speaking, the end of the liquid guide wick near the top extends beyond the top of the diaphragm of the core body, reaching as far as the lower plastic part of the battery top cover. More preferably, the end of the liquid guide wick near the bottom extends at least to the bottom end face of the core body. Here, the bottom end face of the core body refers to the large surface of the core body near the bottom of the housing. That is, the end of the liquid guide wick near the bottom is flush with or extends beyond the bottom end face of the core body.

[0043] Specifically, the shell has a first direction, a second direction, and a third direction that are perpendicular to each other. The first direction is the direction from the bottom end to the top end of the shell, i.e., the height direction of the shell. Taking a rectangular shell as an example, when the second direction is the width direction of the shell, the third direction is the length direction of the shell; when the second direction is the length direction of the shell, the third direction is the width direction of the shell.

[0044] When the number of core bodies in a core assembly is at least two, the at least two core bodies are arranged side by side. Specifically, the at least two core bodies are arranged sequentially along a second direction or along a second direction.

[0045] In some embodiments, the total volume of the core assembly is 90% to 98% of the volume of the housing, thereby maximizing space utilization.

[0046] In this invention, the liquid-guiding core is strip-shaped and extends along the height direction of the shell into the gap between the core assembly and the shell to fill it. The cross-sectional shape of the liquid-guiding core is at least one of a circle, polygon, ellipse, or irregular shape, and its size is mainly adjusted according to the size of the gap. That is, the cross-sectional shape of the liquid-guiding core in this invention can be a single circle, polygon, ellipse, or irregular shape, or a combination of different shapes, such as a combination of circle and rectangle, circle and triangle, ellipse and rectangle, etc. Those skilled in the art can adapt the shape of the liquid-guiding core to the contour of the gap formed between the shell and the core body. The cross-sectional shape of the liquid-guiding core in this invention is preferably circular or elliptical to better fit the radius (R) of the core body.

[0047] The liquid-conducting core has a porous capillary structure. After electrolyte injection, the core transports the electrolyte near the bottom of the casing upwards through capillary action, continuously accumulating at the edge of the core electrode near the top for electrolyte replenishment. The liquid-conducting core is positioned within the ineffective gap between the casing and the core body, thus not increasing the overall battery volume and requiring no changes to the manufacturing process; it can be directly used in existing production processes.

[0048] In some embodiments, the porosity of the portion of the liquid guiding core near the bottom end is less than the porosity of the portion of the liquid guiding core near the top end, and the pore size of the porous capillary structure of the portion of the liquid guiding core near the bottom end is less than the pore size of the porous capillary structure of the portion of the liquid guiding core near the top end. In some embodiments, the porosity of the fluid guiding core is 5% to 80%.

[0049] Furthermore, the porosity of the liquid guiding core increases in a gradient from the end near the bottom to the end near the top.

[0050] In some embodiments, the material of the liquid-conducting core includes at least one of a polymer porous body, a ceramic porous body, glass fiber paper, or foamed metal. The polymer porous body includes, but is not limited to, at least one of polyethylene, polypropylene, polyimide, and cellulose-based materials; the ceramic porous body includes, but is not limited to, SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC, etc.; the glass fiber paper is an inorganic non-metallic thin paper with glass fiber as the main raw material, exhibiting high porosity and resistance to strong acids and alkalis. The foamed metal includes, but is not limited to, foamed nickel, foamed copper, foamed titanium, etc.

[0051] In some embodiments, the fluid-conducting core is a monolithic homogeneous structure, or a composite structure consisting of an inner core and a coating layer surrounding the inner core. The monolithic homogeneous structure refers to an integral structure made of a single material, such as a single porous polymer, a single porous ceramic, a single glass fiber paper, or a single foamed metal. In the composite structure, the materials of the inner core and the coating layer can be different, such as a foamed metal inner core, and a polymer coating layer, an inorganic ceramic coating layer, or a carbon coating layer covering the foamed metal inner core. Furthermore, the coating layer can cover part or all of the surface.

[0052] In some embodiments, the liquid-conducting core is a one-piece, single-material component, or a spliced ​​component formed by connecting at least two segments of different porous materials end-to-end along the axial direction. The one-piece, single-material component refers to a liquid-conducting core made of a continuous, single material, such as a single polymer porous body, a single ceramic porous body, a single glass fiber paper, or a single foamed metal. The spliced ​​component refers to a liquid-conducting core made of at least two different materials along its axial direction, such as a spliced ​​structure of polymer porous body and ceramic porous body, a spliced ​​structure of ceramic porous body and glass fiber paper, a spliced ​​structure of glass fiber paper and foamed metal, or a spliced ​​structure of polymer porous body and foamed metal, etc.

[0053] The gaps formed by the housing and the core assembly include a first gap and a second gap. The first gap is formed by the outer wall of one core body, the side wall of the housing in the second direction, and the side wall of the housing in the third direction, such that the liquid-guiding core located in the first gap is in contact with only one core body. The second gap is formed by the outer wall of two adjacent core bodies and the side wall of the housing in the second direction or the third direction, such that the liquid-guiding core located in the second gap is in contact with two adjacent core bodies simultaneously. Taking a square housing as an example, there are only four first gaps, located at the four corners of the housing cavity, and the rest are second gaps.

[0054] In some embodiments, the inner wall of the housing is further provided with an insulating layer to prevent direct contact between the housing and the core from causing an internal short circuit. The insulating layer encloses the core assembly and the liquid-guiding core within it, and the insulating layer covers the side and bottom surfaces of the core assembly and the liquid-guiding core to form an integral structure. During assembly, the core assembly is wrapped with the insulating layer, and then the liquid-guiding core is inserted into the gap formed between the core body and the inner surface of the insulating layer. The material of the insulating layer includes, but is not limited to, Mylar film, polyester, polypropylene, polyimide, polybutylene terephthalate, and alumina layer. It should be noted that the bottom surface refers to the surface near the bottom end of the housing.

[0055] The electrolyte is filled into the casing to wet the electrode sheets of the core assembly. Before injection, the casing is evacuated to remove air from the battery and reduce injection resistance. Then, an injection pump precisely and quantitatively injects the electrolyte into the casing through the injection port. Finally, the casing is allowed to stand to allow the electrolyte to penetrate and wet the electrode sheets of the core assembly. The electrolyte has different components depending on the battery type. Taking lithium batteries as an example, the electrolyte can be an organic liquid electrolyte, specifically including a solvent, lithium salt, and additives. The solvent includes at least one of dimethyl carbonate, diethyl carbonate, ethylene carbonate, and methyl ethyl carbonate; the additives include at least one of propylene carbonate, butenyl carbonate, ethyl acetate, and propyl propionate; and the lithium salt includes at least one of lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

[0056] In some embodiments, the volume of the electrolyte is 20% to 45% of the volume of the casing to avoid insufficient electrolyte injection, which would increase internal resistance, cause lithium plating, and reduce battery capacity. At the same time, it prevents excessive electrolyte injection, which would cause battery bulging and reduce battery energy density.

[0057] In another specific embodiment, the present invention provides a battery pack comprising a battery as described in a specific embodiment.

[0058] The battery pack also includes cover plate components, thermal management components, electrical connection components, busbar components, etc., required to complete the process. Conventional components in the art can be used, and the present invention does not specifically limit its specific structure and layout.

[0059] In another specific embodiment, the present invention also provides an electrical device that includes the battery pack described in another specific embodiment.

[0060] The electrical devices mentioned include, but are not limited to, power batteries, electric vehicles, electric toys, drones, spacecraft, power tools, mobile phones, robots, smartwatches, digital cameras, tablets, Bluetooth speakers, medical devices, energy storage power stations, smart door locks, and energy storage equipment.

[0061] Example 1 This embodiment provides a square wound battery, such as Figure 1As shown, the device includes a housing 1, made of aluminum, with opposing top and bottom ends. Inside, a core assembly and an electrolyte are arranged, allowing the electrolyte to permeate the core assembly. The direction from the bottom end of the housing 1 to the top end is denoted as the first direction X. The core assembly includes two core bodies 2 arranged in parallel along a second direction, each core body 2 forming a racetrack shape extending along a third direction. The first direction X, the second direction Y, and the third direction Z are mutually perpendicular. The volume of the core assembly is 97% of the volume of the housing 1, and the volume of the electrolyte is 35% of the volume of the housing 1. A first gap is formed between the sidewall of the core body 2 and the housing 1 in the second direction Y and the sidewall of the housing 1 in the third direction Z. A second gap is formed between the outer wall of two adjacent core bodies 2 and the inner sidewall of the housing 1 in the second direction Y. A strip-shaped liquid-guiding core 3 is arranged within both the first and second gaps, extending along the first direction X, and the liquid-guiding core 3 has a circular cross-section. The outer surface of the liquid-conducting core 3 located in the first gap is fitted with the outer wall surface of one core body 2, while the outer surface of the liquid-conducting core 3 located in the second gap is fitted with the outer walls of both core bodies 2. The end of the liquid-conducting core 3 near the top of the housing 1 is flush with the end face of the core body 2, and the end of the liquid-conducting core 3 near the bottom of the housing 1 extends into the electrolyte located at the bottom of the housing 1. The liquid-conducting core 3 is made of glass fiber paper and has a porous capillary structure. The porosity of the liquid-conducting core 3 ranges from 20% to 60%, and the porosity of the portion of the liquid-conducting core 3 near the bottom is less than that near the top, and the pore size of the porous capillary structure of the portion of the liquid-conducting core 3 near the bottom is smaller than that of the portion near the top.

[0062] Example 2 This embodiment provides a square wound battery, which differs from Embodiment 1 in that the liquid guiding core 3 is made of Al2O3 ceramic porous body with a porosity range of 25% to 80%, while the rest of the structure is the same as that of Embodiment 1.

[0063] Example 3 This embodiment provides a square wound battery, which differs from Embodiment 1 in that the liquid guiding core 3 is made of nickel foam with a porosity range of 30% to 75%, while the rest of the structure is the same as that of Embodiment 1.

[0064] Example 4 This embodiment provides a square wound battery, which differs from Embodiment 1 in that the liquid guiding core 3 is a spliced ​​structure formed by connecting Al2O3 ceramic porous body and nickel foam along its axial direction, with a porosity range of 25% to 70%. The rest of the structure is the same as that of Embodiment 1.

[0065] Example 5 This embodiment provides a square wound battery, which differs from Embodiment 1 in that the liquid guiding core 3 is a spliced ​​structure formed by connecting polyethylene and glass fiber paper along its axial direction, and its porosity ranges from 25% to 70%. The rest of the structure is the same as that of Embodiment 1.

[0066] Example 6 This embodiment provides a square wound battery, which differs from Embodiment 1 in that: the liquid guiding core 3 includes an inner core and a coating layer wrapped around the outer periphery of the inner core. The inner core is made of foamed copper, and the coating layer is a carbon coating layer with a porosity range of 35% to 75%. The rest of the structure is the same as that of Embodiment 1.

[0067] Example 7 This embodiment provides a square wound battery, which includes a housing 1 made of aluminum with opposing top and bottom ends. Inside the housing is a core assembly and an electrolyte, with the electrolyte permeating the core assembly. The direction from the bottom end of the housing 1 to the top end is denoted as the first direction X. The core assembly includes four core bodies 2 arranged in parallel along a second direction, each core body 2 forming a racetrack shape extending along a third direction. The first direction X, the second direction Y, and the third direction Z are mutually perpendicular. The volume of the core assembly is 98% of the volume of the housing 1, and the volume of the electrolyte is 45% of the volume of the housing 1. An insulating layer 4, made of Mylar film, is also provided inside the housing 1. The insulating layer 4 wraps the side and bottom surfaces of the core assembly and the electrolyte-conducting core 3. A first gap is formed between the core body, the sidewall of the insulating layer 4 in the second direction Y, and the sidewall of the insulating layer 4 in the third direction Z. A second gap is formed between the outer wall of two adjacent core bodies 2 and the inner sidewall of the insulating layer 4 in the second direction Y. Both the first and second gaps contain strip-shaped liquid-conducting cores 3, which extend along the first direction X and have a circular cross-section. The outer surface of the liquid-conducting core 3 in the first gap is fitted with the outer wall of one core body, while the outer surface of the liquid-conducting core 3 in the second gap is fitted with the outer walls of two core bodies. The end of the liquid-conducting core 3 near the top of the housing 1 is flush with the end face of the core body, and the end of the liquid-conducting core 3 near the bottom of the housing 1 extends into the electrolyte located at the bottom of the housing 1. The liquid-conducting core 3 is made of glass fiber paper and has a porous capillary structure. The porosity of the liquid-conducting core 3 ranges from 5% to 80%, and increases gradually from the end near the bottom of the housing to the end near the top.

[0068] Example 8 This embodiment provides a square wound battery, which differs from Embodiment 1 in that the porosity of the liquid guiding core 3 is uniform, while the rest of the structure is the same as that of Embodiment 1.

[0069] Comparative Example 1 This comparative example provides a square wound battery, which differs from Example 1 in that it does not have a liquid guiding core 3, but the rest of the structure is the same as Example 1.

[0070] Comparative Example 2 This comparative example provides a square wound battery, which differs from Example 1 in that a liquid-guiding aluminum tube is provided between the two wound core bodies, while the rest of the structure is the same as that of Example 1.

[0071] In this invention, the square wound cells of Examples 1-8 and Comparative Examples 1-2 were cycled to 80% SOC at 25°C and 1C, and the wetting of the edge of the main electrode sheet of the wound core near the top of the shell and whether lithium plating and gas expansion occurred were observed.

[0072] In the later stages of cycling of the batteries of Examples 1-8 of this invention, the top edges of the electrode sheets of the core body are uniformly wetted, with no obvious dry areas. In contrast, in the battery of Comparative Example 1, the top edges of the electrode sheets of the core body are obviously dry in the later stages of cycling, forming localized whitish dry areas; in the battery of Comparative Example 2, the central area of ​​the electrode sheets of the core body is wet in the later stages of cycling, but the top edges are slightly dry, indicating that the electrolyte has not been completely consumed.

[0073] In the batteries of Examples 1-8 of this invention, no obvious lithium deposition was observed at the edge of the negative electrode sheet of the core body during the later stages of cycling. In contrast, the battery of Comparative Example 1 showed obvious lithium deposition at the edge of the negative electrode sheet after cycling, while the battery of Comparative Example 2 showed slight lithium deposition at the edge of the negative electrode sheet after cycling.

[0074] The electrolyte injection coefficient of the batteries in Examples 1-7 of this invention is 3.2 g / Ah, and the electrolyte conductivity of Example 8 is 3.4 g / Ah. The electrolyte injection coefficient of the battery in Comparative Example 1 is 3.5 g / Ah, and the electrolyte injection coefficient of the battery in Comparative Example 2 is 3.4 g / Ah. The conventional injection amounts in Comparative Examples 1 and 2 are sufficient for basic wetting, while the batteries in Examples 1-6 achieve better wetting even with an approximately 8% reduction in injection amount. Furthermore, compared to Comparative Examples 1 and 2, the reduced injection amount in Examples 1-6 significantly reduces gas expansion and significantly lowers the cell volume expansion rate.

[0075] The present invention tested the number of cycles when the capacity retention rate of the square wound cells of Examples 1 to 8 and Comparative Examples 1 to 2 reached 80%, and the results are shown in Table 1.

[0076] Table 1 As can be seen from Table 1, compared with Comparative Example 1, the cycle life of Examples 1-8 is effectively improved. This is mainly because the present invention arranges a porous liquid-guiding core in the gap between the core body and the shell, which directionally enriches the electrolyte at the bottom of the shell cavity to the top, so as to fully wet the top edge of the electrode sheet of the core body, avoid edge lithium deposition, and thus improve the battery cycle life. Compared with Comparative Example 2, the present invention can still maintain a good cycle life without excessive electrolyte injection, and does not require changes to the original production, simplifying the battery assembly process and reducing costs.

[0077] This invention incorporates a liquid-conducting core within the ineffective space inside the casing, significantly improving the electrolyte wetting effect at the tip edge of the electrode, preventing drying out, extending cell cycle life, and reducing the risk of lithium plating. Furthermore, this invention achieves directional enrichment of the electrolyte, achieving better wetting without excessive electrolyte injection. In addition, this invention requires no modification to the original cell structure and production process, has high space utilization, is easy to assemble, and is suitable for mass production.

[0078] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0079] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A battery, characterized in that, The battery includes a casing, a winding core assembly, an electrolyte, and several liquid-conducting cores. The casing has opposing top and bottom ends. The winding core assembly, liquid-conducting cores, and electrolyte are all disposed within the casing. The electrolyte is immersed in the winding core assembly and the liquid-conducting cores. The winding core assembly includes at least one winding core body. The liquid guiding core is disposed between the core assembly and the housing, the liquid guiding core extends from the bottom end to the top end, and the outer surface of the liquid guiding core is in contact with the outer wall surface of at least one of the core bodies.

2. The battery according to claim 1, characterized in that, The liquid guiding core has a strip structure; And / or, the end of the liquid guiding core near the top is not lower than the end face of the core body, and the end of the liquid guiding core near the bottom extends into the electrolyte located at the bottom of the housing.

3. The battery according to claim 1, characterized in that, The battery also includes an insulating layer that wraps around the side and bottom surfaces of the winding core and the liquid guiding core to form an integral structure.

4. The battery according to any one of claims 1-3, characterized in that, The fluid-conducting core has a porous capillary structure.

5. The battery according to claim 4, characterized in that, The porosity of the liquid guiding core near the bottom is less than that of the liquid guiding core near the top, and the pore size of the porous capillary structure of the liquid guiding core near the bottom is less than that of the porous capillary structure of the liquid guiding core near the top.

6. The battery according to claim 5, characterized in that, The porosity of the liquid guiding core increases in a gradient from the end near the bottom to the end near the top. And / or, the porosity of the fluid guiding core is 5% to 80%.

7. The battery according to claim 4, characterized in that, The material of the liquid guiding core includes at least one of the following: polymer porous body, ceramic porous body, glass fiber paper or foam metal. And / or, the cross-section of the fluid guiding core is at least one of a circular, polygonal, elliptical, or irregular shape; And / or, the liquid guiding core is a monolithic homogeneous structure, or a composite structure consisting of an inner core and a coating layer surrounding the outer periphery of the inner core; And / or, the fluid guiding core is an integral single-material component, or a spliced ​​component formed by connecting at least two different porous materials end to end along the axial direction.

8. The battery according to claim 1 or 2, characterized in that, The total volume of the core assembly is 90% to 98% of the volume of the housing; And / or, the volume of the electrolyte is 20% to 45% of the volume of the casing.

9. A battery pack, characterized in that, The battery pack includes the battery as described in any one of claims 1-8.

10. An electrical device, characterized in that, The electrical device includes the battery pack as described in claim 9.

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