A battery structure

Abstract

This utility model discloses a battery structure, which includes a core pack, a protective film, a shell, and an electrolyte. The protective film covers the outer periphery of the core pack and includes an interconnected insulating layer and an elastic layer. The insulating layer is connected to the core pack. A flow channel is formed on the side of the elastic layer away from the core pack, and the flow channel penetrates the elastic layer along the height direction of the core pack. The shell has a receiving cavity for accommodating the core pack and the protective film. The elastic layer is in contact with the shell and is in a compressed state. The electrolyte is disposed in the receiving cavity. This design aims to solve the technical problem of structural unevenness caused by electrolyte deposition.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery structure. Background Technology

[0002] In existing battery manufacturing processes, electrolyte needs to be injected into the battery to ensure the formation of good ion channels between the electrodes and the separator, meeting the charging and discharging requirements. However, in practical applications, due to gravity, the injected electrolyte tends to deposit in the bottom vertical region of the battery, resulting in uneven distribution of the electrolyte inside the cell.

[0003] After the electrolyte accumulates at the bottom, the lower part of the cell pack absorbs more electrolyte and expands more, while the upper and middle parts absorb less electrolyte and have less thickness variation. This difference in distribution directly leads to uneven stress distribution in the thickness direction of the cell pack, resulting in varying degrees of stress concentration in local areas. With repeated charge-discharge cycles, this uneven stress can easily cause various abnormal phenomena, such as decreased cycle life, rapid capacity decay (i.e., cycle failure), local interface delamination of the cell pack, electrode warping and deformation, and even, in severe cases, internal short circuits and other safety hazards.

[0004] Therefore, there is an urgent need to propose a novel battery structure to mitigate the structural inhomogeneity caused by electrolyte deposition. Utility Model Content

[0005] One objective of this invention is to provide a battery structure that addresses the technical problem of structural unevenness caused by electrolyte deposition.

[0006] To achieve the above objectives, the present invention provides a solution as follows: a battery structure comprising a core pack; a protective film covering the outer periphery of the core pack, the protective film comprising an interconnected insulating layer and an elastic layer, the insulating layer being connected to the core pack, and the elastic layer having a flow channel on the side away from the core pack, the flow channel penetrating the elastic layer along the height direction of the core pack; a shell having a receiving cavity for receiving the core pack and the protective film, the elastic layer being in contact with the shell and in a compressed state; and an electrolyte disposed in the receiving cavity.

[0007] Optionally, there may be multiple flow channels, which are arranged circumferentially around the core package.

[0008] Optionally, the elastic layer is also provided with branch channels, and the flow channels are interconnected through the branch channels to form a mesh-like flow guiding structure.

[0009] Optionally, the thickness S1 of the protective film and the distance S2 between the core and the shell satisfy the following condition: 1.1S2≤S1≤1.3S2.

[0010] Optionally, the thickness S3 of the elastic layer and the thickness S4 of the isolation layer satisfy the following condition: 2S4≤S3≤5S4.

[0011] Optionally, the protective membrane also includes a porous adsorption layer disposed on the sidewall surface of the flow channel for adsorbing electrolyte.

[0012] Optionally, the protective membrane also includes a porous adsorption layer, which is laid at the bottom of the flow channel.

[0013] Optionally, the thickness S5 of the porous adsorption layer and the channel depth H satisfy the following relationship: 0.1H≤S5≤0.3H.

[0014] Optionally, the thickness of the porous adsorption layer is gradient-distributed in the direction of core height, gradually decreasing from the top to the bottom of the shell.

[0015] Alternatively, the protective film can be fixedly attached to the outer surface of the core package by hot melt adhesive or snap-fit ​​structure.

[0016] The beneficial effects of this utility model are as follows:

[0017] Compared to existing technologies that rely solely on an insulating layer for insulation between the core pack and the casing, without effectively controlling electrolyte distribution, this application integrates isolation, protection, buffering, and liquid regulation functions by incorporating a protective film with a flow channel structure around the core pack. On one hand, the insulating layer effectively blocks direct contact between the core pack and the casing, reducing the risk of short circuits. On the other hand, the elastic layer guides the electrolyte to diffuse and disperse into the internal flow channels when deformed under pressure, preventing electrolyte deposition at the bottom of the battery under gravity and alleviating the problem of a thicker bottom and thinner top core pack. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is an overall schematic diagram of the battery structure provided in this embodiment of the utility model;

[0020] Figure 2 This is a schematic cross-sectional view of the battery structure provided in an embodiment of this utility model;

[0021] Figure 3 This is a schematic diagram of the structure of the protective film provided in an embodiment of the present invention;

[0022] Figure 4 This is a top view of the protective film provided in an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of a flow channel structure provided in an embodiment of the present utility model;

[0024] Figure 6 This is a schematic diagram of another flow channel structure provided in an embodiment of the present utility model;

[0025] Figure 7 This is a cross-sectional view of the protective film provided in this embodiment of the present invention along the height direction.

[0026] Explanation of icon numbers:

[0027] 10. Core package; 20. Protective film; 21. Isolation layer; 22. Elastic layer; 221. Flow channel; 222. Branch channel; 23. Porous adsorption layer; 30. Shell. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indicator will also change accordingly.

[0030] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.

[0031] Please see Figures 1 to 3 , Figure 1 This is an overall schematic diagram of the battery structure provided in an embodiment of the present invention. Figure 2 This is a schematic cross-sectional view of the battery structure provided in an embodiment of this utility model. Figure 3 This is a schematic diagram of the structure of the protective film 20 provided in this embodiment of the utility model. Figure 3 The Z direction shown is the height direction of the core package 10.

[0032] This utility model provides a battery structure designed to alleviate the problem of uneven electrolyte deposition inside the cell, thereby improving the stress distribution of the cell pack 10 and enhancing the cycle stability and lifespan of the battery.

[0033] The battery structure includes a core pack 10, a protective film 20, a casing 30, and an electrolyte. The protective film 20 covers the outer periphery of the core pack 10, forming an isolation and buffer between the core pack 10 and the casing 30. Specifically, the core pack 10 is a stacked or wound structure of electrodes and separators, constituting the core unit for energy storage inside the battery. The protective film 20 is provided on the outer periphery of the core pack 10, and the protective film 20 includes an interconnected insulating layer 21 and an elastic layer 22. The insulating layer 21 is located on the side of the core pack 10, covering the outer surface of the core pack 10, and serves to provide electrical insulation, prevent the core pack 10 from directly contacting the inner wall of the casing 30, and provide basic structural support.

[0034] The elastic layer 22 is disposed on the side of the separator 21 away from the core pack 10 and contacts the inner wall of the housing 30's receiving cavity. The elastic layer 22 is made of a compressible material. A flow channel 221 is formed on the side of the elastic layer 22 away from the core pack 10. The flow channel 221 extends along the height direction of the core pack 10 (i.e., the vertical direction of the battery) and runs through the entire elastic layer 22, thereby forming a continuous liquid guiding channel. The shape of the flow channel 221 is specifically designed and optimized according to the size of the core pack 10 and the liquid injection volume to achieve the best drainage effect.

[0035] The housing 30 has an internal cavity for accommodating the core pack 10 and the protective film 20 covering the outer periphery of the core pack 10. After the core pack 10 and the protective film 20 are installed into the housing 30, the elastic layer 22 is in close contact with the inner wall of the housing 30 and is compressed because the assembly gap is smaller than the initial thickness of the protective film 20. During compression, the elastic layer 22 deforms, providing stable support for the core pack 10 and forcing the electrolyte to flow into the channels 221 within a limited space. Ultimately, the electrolyte is evenly dispersed into the various channels 221 within the elastic layer 22, preventing it from accumulating at the bottom of the battery due to gravity.

[0036] In this embodiment, the present application provides a protective film 20 with a flow channel 221 structure around the outer periphery of the core pack 10. This effectively isolates the core pack 10 from the casing 30, preventing short-circuit risks caused by direct contact. Furthermore, utilizing the compressibility of the elastic layer 22, when the protective film 20 is under pressure upon contact with the casing 30, it promotes the diffusion and dispersion of the electrolyte into the flow channel 221, preventing electrolyte deposition at the bottom of the battery under gravity. Through this structural design, the protective film 20 not only fulfills the traditional functions of isolation and protection but also combines spatial buffering and liquid regulation. This results in a more uniform distribution of the electrolyte within the battery, effectively mitigating the thickness difference between the bottom and upper middle parts of the core pack 10, and preventing abnormalities such as electrode warping, interface peeling, and capacity drops caused by uneven local stress. This significantly improves the battery's cycle performance and reliability.

[0037] In some embodiments, there are multiple flow channels 221, and these multiple flow channels 221 are arranged circumferentially around the core package 10. Specifically, a plurality of flow channel 221 structures spaced apart from each other are formed and distributed inside the elastic layer 22 along the circumference of the core package 10, that is, around the outer periphery of the core package 10. The flow channels 221 are arranged according to a predetermined spacing pattern, and can present various arrangements such as annular, arc-shaped, radial, or zigzag, and are optimized according to the specific size and shape of the core package 10.

[0038] By arranging multiple flow channels 221 at circumferential intervals, the electrolyte can not only be guided to flow along the height of the cell inside the protective film 20, but also be laterally dispersed in the circumferential direction, thereby further improving the uniform distribution of the electrolyte on the outer periphery of the cell pack 10. Especially during long-term vertical placement or cycling of the battery, the electrolyte is prone to sinking and accumulating due to the combined effect of gravity and internal capillary forces. However, the circumferentially distributed network of flow channels 221 can effectively buffer local liquid accumulation, promote the diffusion of electrolyte along different flow channels 221, and avoid concentrated deposition in a single bottom area.

[0039] Furthermore, the multiple circumferentially spaced flow channels 221 maintain a certain fluid passage when the elastic layer 22 is compressed, preventing it from completely closing due to overall deformation of the elastic layer 22. This ensures good fluid induction and dispersion functions even when the internal space of the casing 30 is limited and the elastic layer 22 is compressed. This layout further enhances the dynamic liquid regulation capability within the cell structure, optimizes the electrolyte distribution, and reduces the risk of localized stress anomalies.

[0040] Furthermore, in some optimized embodiments, in order to enhance the guiding and dispersing ability of the electrolyte within the protective film 20, the elastic layer 22 not only has flow channels 221 along the height direction of the core package 10, but also has multiple branch channels 222 between the flow channels 221. The branch channels 222 are used to achieve liquid communication between adjacent flow channels 221, thereby forming a continuous mesh-like flow guiding structure within the elastic layer 22.

[0041] Specifically, the branch channels 222 preferably extend circumferentially along the core package 10 and intersect with the flow channels 221 arranged along the height direction. Each channel establishes a connection with adjacent flow channels 221 through at least two branch channels 222, thereby forming a crisscrossing grid-like liquid passage network as a whole. With this layout, even if some flow channels 221 are blocked due to external force compression or expansion of the core package 10, the electrolyte can still bypass to other flow channel 221 areas through the branch channels 222, ensuring that the liquid continues to flow freely inside the protective membrane 20 and avoiding local accumulation.

[0042] In practical design, the number of branch channels 222 is matched with the number and arrangement density of flow channels 221. Preferably, at least one branch channel 222 is provided between flow channels 221 every 5 to 20 millimeters. The density of branch channels 222 can be flexibly adjusted according to battery capacity, electrolyte injection volume, and core package 10 size to balance liquid flowability and overall structural strength of elastic layer 22. In addition, the cross-sectional shape of branch channels 222 and flow channels 221 can be rectangular, trapezoidal, semi-circular, or other rounded corner structures to reduce liquid flow resistance and improve drainage efficiency, while reducing local stress concentration and extending the durability of elastic layer 22.

[0043] In this embodiment, the mesh-like flow-guiding structure constructed in the elastic layer 22 not only realizes the multi-path diffusion and balance of the electrolyte in space, but also endows the protective film 20 with better deformation adaptability and local liquid buffering capacity. For example, during battery operation, when the expansion of the core pack 10 causes the elastic layer 22 to deform, the flow channel 221 and the branch channel 222 can maintain a basic communication state through local stretching or contraction, avoiding complete closure of the channel due to compression. This effectively alleviates the uneven stress and abnormal thickness of the core pack 10 caused by electrolyte deposition at the bottom, as well as the resulting performance failure problems such as cycle diving and interface abnormalities, thereby significantly improving the overall cycle stability and service life of the battery.

[0044] In some embodiments, please refer to Figure 2 and Figure 4 , Figure 2 This is a schematic cross-sectional view of the battery structure provided in an embodiment of this utility model. Figure 4This is a top view of the protective film 20 provided in this embodiment of the utility model. In order to balance the compression buffering effect of the protective film 20 and the electrolyte guiding and dispersing effect, a specific dimensional relationship is set between the initial thickness S1 of the protective film 20 and the original distance S2 between the outer surface of the core package 10 and the inner wall of the shell 30, specifically satisfying the following relationship: 1.1S2≤S1≤1.3S2.

[0045] When the thickness S1 of the protective film 20 is close to 1.1 times S2, the protective film 20 undergoes moderate compression during assembly, providing basic flexible support for the core package 10. Simultaneously, the deformation of the elastic layer 22 forces the electrolyte to be squeezed into the flow channel 221, initially achieving liquid guidance and dispersion. However, if S1 is too small, i.e., S1 is below 1.1S2, the compression between the protective film 20 and the shell 30 is insufficient, and the deformation of the elastic layer 22 is limited. This fails to generate enough pressure to effectively push the electrolyte into the flow channel 221, resulting in reduced liquid flow within the flow channel 221. A large amount of electrolyte remains stagnant in the bottom region of the core package 10, failing to achieve the desired dispersion effect and thus making it difficult to alleviate the uneven stress problem caused by electrolyte deposition.

[0046] Conversely, when the thickness S1 of the protective film 20 is close to or slightly greater than 1.3 times S2, the protective film 20 will be compressed more significantly during assembly, enhancing the support provided by the elastic layer 22. Simultaneously, the electrolyte can be fully squeezed into the flow channel 221 initially, improving liquid dispersion efficiency. However, if S1 increases further beyond a reasonable range—that is, if the thickness of the protective film 20 is much greater than the gap between the core package 10 and the shell 30—the protective film 20 will be over-compressed under pressure, causing severe collapse or blockage of the internal flow channel 221 structure. In this case, the flow channel 221, originally used to guide the electrolyte flow, is compressed, deformed, or blocked. The electrolyte loses its effective flow channel and instead stagnates in a localized area, causing liquid accumulation, abnormal local pressure, and potentially even leading to uneven expansion of the core package 10 or localized electrode failure.

[0047] Therefore, by controlling the thickness S1 of the protective film 20 to be between 1.1 and 1.3 times the gap S2 between the core package 10 and the shell 30, it is possible to ensure that the protective film 20 has a certain compressibility deformation while avoiding the situation where the elastic layer 22 is over-compressed and the flow channel 221 is blocked. This maximizes the dual functions of the protective film 20 as a buffer support and electrolyte guide, thereby achieving uniform distribution of electrolyte inside the cell and improving structural stability and cycle reliability.

[0048] In some embodiments, the protective film 20 is mainly composed of an insulating layer 21 and an elastic layer 22. The insulating layer 21 is close to the core package 10 and mainly provides electrical insulation, physical protection, and surface stability support, while the elastic layer 22 is close to the housing 30 and provides elastic compression, buffer deformation, and electrolyte guidance functions after the cell is assembled. Therefore, in the structural design, the thickness of the two layers needs to be reasonably configured according to their respective functions. Preferably, a specific proportional relationship is set between the thickness S3 of the elastic layer 22 and the thickness S4 of the insulating layer 21: 2S4≤S3≤5S4.

[0049] When the thickness S3 of the elastic layer 22 is approximately twice the thickness S4 of the separator layer 21, the protective film 20 can ensure the basic electrical insulation strength and structural support. At the same time, the elastic layer 22 has a certain deformation capacity, which can be moderately compressed during battery assembly to form flexible support and electrolyte flow guidance functions. This is suitable for battery designs with a relatively thin overall thickness of the protective film 20 and limited space, balancing compactness and functionality.

[0050] When the thickness S3 of the elastic layer 22 is further increased, approaching five times the thickness S4 of the insulating layer 21, the elastic layer 22 becomes dominant in the overall protective film 20. This design provides greater compressibility deformation, better absorbs the dimensional changes of the core package 10 caused by charge-discharge cycle expansion, and simultaneously forms more significant electrolyte flow channels within the protective film 20, promoting sufficient diffusion of the electrolyte in different flow channels 221. However, if the thickness of the elastic layer 22 is too large, exceeding five times the thickness of the insulating layer 21, the protective film 20 may become too soft overall, lacking the necessary initial support rigidity, affecting the positioning stability of the core package 10, and easily causing the flow channels 221 to collapse under local compression, thus weakening the fluid guiding capability.

[0051] Conversely, if the thickness of the elastic layer 22 is too small, less than twice the thickness of the insulating layer 21, the compressibility deformation of the elastic layer 22 itself is insufficient, making it difficult to effectively absorb the volume change caused by the deformation of the core package 10 when the protective film 20 is under pressure, and it is also difficult to form a sufficient liquid guiding space, thereby weakening the effect of electrolyte dispersion and buffer protection.

[0052] Therefore, by limiting the ratio of the thickness of the elastic layer 22 to the isolation layer 21 to be within the range of 2:1 to 5:1, it is possible to ensure that the overall protective film 20 has good electrical isolation performance while giving the protective film 20 the necessary flexible compression capability and fluid conduction control function, thereby effectively improving the stability of the internal structure of the cell, improving the uniformity of electrolyte distribution, reducing the risk of local stress concentration, and extending the cycle life of the battery.

[0053] In some optimized embodiments, please refer to Figure 5 , Figure 5This is a schematic diagram of a flow channel 221 structure provided in an embodiment of the present invention. To further enhance the ability of the protective membrane 20 to regulate and manage the electrolyte, the protective membrane 20 also includes a porous adsorption layer 23. The porous adsorption layer 23 is preferably disposed on the sidewall surface of the flow channel 221 and extends along the flow channel 221, for adsorbing and storing the electrolyte entering the flow channel 221.

[0054] The porous adsorption layer 23 is made of a material with an open microporous structure, such as high-porosity foam, nanofiber felt, or hydrophilic modified porous polymer material. This porous structure can form a large number of tiny liquid adsorption points on the surface of the flow channel 221. When the electrolyte enters the flow channel 221 under pressure through the elastic layer 22, some of the liquid can be quickly adsorbed and fixed by the porous adsorption layer 23, preventing the electrolyte from accumulating over a large area or floating freely in the flow channel 221, thereby improving the uniformity and stability of the liquid distribution.

[0055] Furthermore, the porous adsorption layer 23 is disposed on the sidewall of the flow channel 221, rather than completely covering the entire cross-section of the flow channel 221. This effectively increases the liquid absorption area while maintaining the connectivity of the main channel, thereby enhancing the local liquid fixation and regulation function without significantly hindering liquid flow. Especially during long-term battery cycling, due to temperature changes or changes in the volume of the core pack 10, the electrolyte may migrate slightly. The porous adsorption layer 23 on the sidewall of the flow channel 221 can capture and store small amounts of free liquid in a timely manner, maintaining the dynamic balance of liquid distribution inside the cell.

[0056] In addition, the porous adsorption layer 23 also has a certain buffering and energy absorption effect. When the protective film 20 is deformed by pressure, it can work together with the elastic layer 22 to disperse external stress, reduce the risk of blockage of the flow channel 221 caused by local compression, and extend the service life of the protective film 20 and the entire battery cell.

[0057] Further, please refer to Figure 6 , Figure 6 This is a schematic diagram of another flow channel 221 structure provided by an embodiment of the present invention. In some different optimized embodiments, in order to achieve directional collection and dispersion of the electrolyte, the porous adsorption layer 23 in the protective film 20 is disposed in the bottom region of the flow channel 221, and is not laid on the side wall of the flow channel 221. Specifically, the porous adsorption layer 23 covers the bottom surface of the flow channel 221, is arranged continuously or intermittently along the length direction of the flow channel 221, and is in direct contact with the bottom of the elastic layer 22 to form a bottom liquid adsorption surface.

[0058] In this embodiment, a porous adsorption layer 23 is provided at the bottom of the flow channel 221. This ensures the main channel of the flow channel 221 remains spacious and unobstructed while adsorbing and locking the electrolyte within the flow channel 221, reducing the risk of the liquid freely floating or accumulating in irregular areas within the flow channel 221. Furthermore, since no adsorption layer is provided on the sidewalls, the main channel of the flow channel 221 maintains a larger open area laterally, which is beneficial for maintaining high fluidity of the electrolyte within the flow channel 221, reducing flow resistance, and avoiding problems such as liquid blockage or decreased flow rate caused by excessive adsorption layers interfering with the liquid flow path. Therefore, this embodiment ensures the liquid collection function while also considering the overall liquid flow efficiency of the flow channel 221.

[0059] Furthermore, in some embodiments, to ensure that the porous adsorption layer 23 has effective adsorption capacity while not significantly hindering the flow of the electrolyte within the flow channel 221, a reasonable dimensional ratio is set between the thickness S5 of the porous adsorption layer 23 and the corresponding depth H of the flow channel 221. Preferably, the thickness S5 of the porous adsorption layer 23 satisfies the following relationship: 0.1H ≤ S5 ≤ 0.3H.

[0060] Specifically, when the thickness S5 of the porous adsorption layer 23 is close to 0.1 times the depth H of the flow channel 221, the porous adsorption layer 23 occupies a small space in the flow channel 221, which can form a thin layer coverage. This can provide basic liquid adsorption capacity without significantly reducing the effective cross-sectional area of ​​the flow channel 221, which helps to maintain the smooth flow of electrolyte in the flow channel 221 and ensures that the electrolyte is evenly dispersed inside the protective film 20.

[0061] When the thickness S5 of the porous adsorption layer 23 is increased to 0.3 times the depth H of the flow channel 221, the porous adsorption layer 23 has a larger adsorption capacity, enabling it to quickly adsorb and fix more electrolyte. This is particularly suitable for battery designs with large electrolyte injection volumes or wide flow channel 221 spaces. A thicker adsorption layer can effectively buffer electrolyte migration during battery operation, reducing the risk of liquid accumulation caused by changes in cell orientation or local thermal expansion, and improving the dynamic stability of liquid management.

[0062] However, if the thickness S5 of the porous adsorption layer 23 is less than 0.1H, the adsorption capacity is limited, making it difficult to form a sufficient liquid fixation effect. This can easily lead to some electrolyte still floating freely inside the flow channel 221, negating the technical significance of setting up the porous adsorption layer 23. Conversely, if S5 is greater than 0.3H, the porous adsorption layer 23 occupies a large space inside the flow channel 221, significantly compressing the free flow channel of the liquid, increasing the liquid flow resistance, and even causing local blockage when the elastic layer 22 is under pressure. This affects the distribution efficiency of the electrolyte inside the protective film 20, leading to local accumulation and abnormal pressure.

[0063] Therefore, by limiting the thickness S5 of the porous adsorption layer 23 to within 10% to 30% of the depth H of the flow channel 221, a good balance can be achieved between the free flow of liquid and the adsorption and fixation capacity, ensuring the liquid dispersion, guidance and buffering functions inside the protective film 20, while optimizing the internal stability and cycle life of the battery structure.

[0064] In some optimized embodiments, please refer to Figure 7 , Figure 7 This is a cross-sectional schematic diagram of the protective film 20 provided in this embodiment of the present invention along the height direction. The thickness of the porous adsorption layer 23 is set to a gradient distribution along the height direction of the core package 10. Specifically, the thickness of the porous adsorption layer 23 gradually decreases from the top region of the shell 30 to the bottom region of the shell 30. That is, in the flow channel 221 region near the top of the shell 30, the porous adsorption layer 23 has a relatively large thickness, while in the flow channel 221 region near the bottom of the shell 30, the thickness of the porous adsorption layer 23 gradually decreases.

[0065] During actual battery operation, due to gravity and the fluidity of the electrolyte itself, the electrolyte tends to deposit towards the bottom of the core pack 10, resulting in significant liquid enrichment in the bottom region. To rationally guide and control the distribution of the electrolyte, a thicker porous adsorption layer 23 is provided in the top region. This layer provides a larger liquid adsorption capacity when the electrolyte initially flows into the flow channel 221, preferentially adsorbing some of the liquid and reducing the speed and amount of liquid directly sinking to the bottom region. This creates a layer-by-layer adsorption and gradually controlled liquid dispersion pattern in the longitudinal direction of the flow channel 221, delaying the liquid enrichment process in the bottom region.

[0066] As the electrolyte moves downwards, the thickness of the porous adsorption layer 23 near the bottom gradually decreases. This retains a certain adsorption capacity to stabilize the residual liquid while minimizing the risk of oversaturation in the bottom space due to an excessively thick adsorption layer, which could compress the effective channel 221 and affect further liquid dispersion and flow. Simultaneously, the thinner adsorption layer in the bottom region provides better spatial adaptability during the micro-expansion of the core pack 10 caused by charge-discharge cycles, reducing liquid blockage or closure of the channel 221 due to localized compression.

[0067] In this embodiment, by setting a thickness gradient, the protective film 20 has a gradient control effect on liquid adsorption capacity in the height direction. The top has a large adsorption capacity and the bottom has a moderate adsorption capacity. Overall, it realizes the orderly guidance and balanced adsorption of electrolyte flow behavior, further optimizes the internal liquid management system of the core package 10, and effectively alleviates problems such as bottom liquid accumulation, local thickness abnormality and uneven interface stress, thereby improving the stability and cycle reliability of the cell structure.

[0068] In some embodiments, the protective film 20 is preferably fixedly connected to the outer surface of the core pack 10 by means of hot melt adhesive bonding or snap-fit ​​structure, so as to ensure that the protective film 20 can stably cover and adhere to the outer surface of the core pack 10, and avoid displacement or falling off during battery assembly and use.

[0069] Hot melt adhesive, a commonly used fast-curing bonding material, can melt and flow under heat. It can be applied to one side of the isolation layer 21 of the protective film 20 or the surface of the core package 10. After the core package 10 and the protective film 20 are bonded together, it cools and cures, forming a strong and continuous adhesive interface. The use of hot melt adhesive can simplify the assembly process of the protective film 20 and the core package 10, adapting to the needs of large-scale automated production.

[0070] The snap-fit ​​structure may include snaps, teeth, or annular grooves located on the edge of the protective film 20. These snap-fit ​​parts are mechanically engaged and embedded into the surface of the core package 10 or into pre-set limiting grooves in the support frame of the core package 10, achieving physical fixation without adhesive. The snap-fit ​​structure offers excellent ease of disassembly and maintenance, allowing for quick assembly and disassembly when subsequent inspection or replacement of the protective film 20 is required, reducing maintenance costs and complexity.

[0071] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0072] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A battery structure, characterized in that, include: Core package; A protective film is wrapped around the outer periphery of the core package. The protective film includes an interlocking isolation layer and an elastic layer. The isolation layer is connected to the core package. The elastic layer has a flow channel on the side away from the core package. The flow channel penetrates the elastic layer along the height direction of the core package. The housing has a receiving cavity for accommodating the core package and the protective film. The elastic layer is in contact with the housing and is in a compressed state. as well as Electrolyte is disposed in the receiving cavity.

2. The battery structure according to claim 1, characterized in that, The number of flow channels is multiple, and the multiple flow channels are arranged circumferentially around the core package.

3. The battery structure according to claim 2, characterized in that, The elastic layer is also provided with branch channels, and the flow channels are interconnected through the branch channels to form a mesh-like flow guiding structure.

4. The battery structure according to claim 1, characterized in that, The thickness S1 of the protective film and the distance S2 between the core and the shell satisfy the following condition: 1.1S2≤S1≤1.3S2.

5. A battery structure according to claim 1, characterized in that, The thickness S3 of the elastic layer and the thickness S4 of the isolation layer satisfy the following condition: 2S4≤S3≤5S4.

6. A battery structure according to any one of claims 1 to 5, characterized in that, The protective film also includes a porous adsorption layer, which is disposed on the sidewall surface of the flow channel and is used to adsorb the electrolyte.

7. A battery structure according to any one of claims 1 to 5, characterized in that, The protective film also includes a porous adsorption layer, which is laid at the bottom of the flow channel.

8. A battery structure according to claim 7, characterized in that, The thickness S5 of the porous adsorption layer and the channel depth H satisfy the following relationship: 0.1H≤S5≤0.3H.

9. A battery structure according to claim 7, characterized in that, The thickness of the porous adsorption layer is gradient-distributed along the height direction of the core package, gradually decreasing from the top to the bottom of the shell.

10. A battery structure according to any one of claims 1 to 5, characterized in that, The protective film is fixedly connected to the outer surface of the core package by hot melt adhesive or snap-fit ​​structure.

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