cell

Abstract

The application discloses an electric core, relates to the technical field of batteries, and relates to an electric core which comprises a shell, a first cover plate assembly and an electrode assembly, the side end of the shell is provided with an opening, the first cover plate assembly is arranged at the opening, the electrode assembly comprises a positive electrode sheet, a diaphragm and a negative electrode sheet which are arranged in a laminated mode along the width direction of the shell, and the positive electrode sheet is connected with the diaphragm through a connecting structure. The electric core is used for solving the risk of positive electrode sheet falling off.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell. Background Technology

[0002] Traditional high-capacity energy storage cells use a stacked, top-mounted electrode method (top-mounted stacking). The cell usage process is as follows: Figure 1 The image shows a vertical arrangement. However, to improve the assembly efficiency and safety performance of the cells in the system, large-capacity energy storage cells will adopt a stacked, side-out terminal configuration (side-out stacked). The usage process of side-out terminal cells is as follows: Figure 2 The side-mounted position shown.

[0003] The battery cell with a side-out electrode structure has an electrode assembly including a positive electrode, a negative electrode, and a separator. However, the positive electrode is prone to falling off, but the relevant technology has not provided a specific solution. Utility Model Content

[0004] The main purpose of this application is to propose a battery cell that effectively solves the risk of positive electrode plate detachment.

[0005] On the one hand, a battery cell is provided, comprising:

[0006] A housing, wherein the side ends of the housing are open;

[0007] A first cover assembly is disposed at the opening;

[0008] An electrode assembly, comprising a positive electrode, a separator, and a negative electrode stacked along the width direction of the housing;

[0009] The positive electrode is connected to the separator via a connection structure.

[0010] In one embodiment, the first cover plate assembly includes:

[0011] Cover plate body;

[0012] The first pole post is disposed on the cover plate body;

[0013] The second pole post is disposed on the cover plate body;

[0014] The positive electrode has a positive tab and the negative electrode has a negative tab. The positive tab of the positive electrode is connected to the first terminal, and the negative tab of the negative electrode is connected to the second terminal.

[0015] In one embodiment, the length of the negative electrode along the height direction of the housing is greater than the length of the positive electrode along the height direction of the housing.

[0016] In one embodiment, the separator is a single-layer membrane, which is folded back and forth and forms multiple spacer layers along the width direction of the housing, with the positive electrode and the negative electrode respectively disposed in adjacent spacer layers.

[0017] In one embodiment, the bottom of the positive electrode is suspended relative to the inner bottom surface of the housing along the height direction of the housing.

[0018] In one embodiment, there are multiple positive electrode plates, a negative electrode plate is disposed between two adjacent positive electrode plates, and a separator is disposed between adjacent positive electrode plates and negative electrode plates.

[0019] In one embodiment, the connection structure is disposed on the side of the positive electrode plate away from the positive electrode tab.

[0020] In one embodiment, the connection structure is disposed on the upper side of the positive electrode plate.

[0021] In one embodiment, the connection structure is disposed on both surfaces of the positive electrode sheet.

[0022] In one embodiment, the length of the connection structure is not less than 50% of the length of the positive electrode sheet, the width of the connection structure is 1% to 3% of the width of the positive electrode sheet, and the thickness of the connection structure is 30 μm to 80 μm.

[0023] In one embodiment, the connection structure uses insulating adhesive.

[0024] In one embodiment, the battery cell further includes a bottom support plate disposed between the lower end face of the electrode assembly and the inner bottom face of the housing.

[0025] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects:

[0026] The first cover plate assembly is located at the opening of the shell, with the opening direction intersecting the direction of gravity. The positive electrode is stably connected to the separator through the connection structure, which can reduce the risk of the positive electrode loosening and falling off, and further solve the short circuit problem caused by falling off, reduce the safety risks throughout the entire life cycle of the cell, and improve the stability and reliability of the overall performance of the cell.

[0027] A connection structure is set on the positive electrode to position and connect the positive electrode to the separator, thereby achieving a stable connection between the positive electrode and the separator. The positive electrode is connected to the separator through the connection structure to form an integral structure, which can also improve the overall structural stability of the electrode assembly, thereby improving the overall structural strength of the cell, simplifying the structural design, and reducing the use of other additional connection structures. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application 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 application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the battery cell with the terminal protruding from the top.

[0030] Figure 2 A schematic diagram of a structural embodiment of a battery cell side terminal post;

[0031] Figure 3 This is a schematic diagram of a battery cell before the side-mounted terminal breaks off;

[0032] Figure 4 This is a schematic diagram of a battery cell after the side-mounted terminal has fallen off.

[0033] Figure 5 This is a schematic diagram of the structure of an embodiment of the positive electrode sheet of this application;

[0034] Figure 6 This is a schematic diagram of the structure of an embodiment of the electrode assembly of this application;

[0035] Figure 7 This is a schematic diagram of the structure of one embodiment of the battery cell of this application;

[0036] Figure 8 This is a disassembly and assembly diagram of one embodiment of the battery cell of this application.

[0037] Explanation of icon numbers:

[0038] 100. Shell;

[0039] 200. Electrode assembly; 210. Positive electrode plate; 211. Positive electrode tab; 220. Separator; 221. Spacer layer; 230. Negative electrode plate; 231. Negative electrode tab; 240. Connecting structure;

[0040] 300, First cover plate assembly; 310, Cover plate body; 311, Injection hole; 320, First electrode post; 330, Second electrode post;

[0041] 400. Second cover plate assembly; 410. Pressure relief structure.

[0042] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0044] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0045] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are 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 with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0046] Traditional high-capacity energy storage cells use a stacked, top-mounted electrode method (top-mounted stacking). The cell usage process is as follows: Figure 1 The image shows a vertical arrangement. However, to improve the assembly efficiency and safety performance of the cells in the system, large-capacity energy storage cells will adopt a laminated configuration with side-mounted terminals (side-mounted lamination). The usage process of cells with side-mounted terminals is as follows: Figure 2 The side-mounted position shown.

[0047] To avoid lithium plating issues caused by large gaps between the positive and negative electrodes, high-capacity energy storage cells use a coated ceramic separator (PE+Al2O3+PVDF) for hot pressing to ensure adhesion between the positive and negative electrodes. After the cell is filled with electrolyte, the high porosity of the coated ceramic separator absorbs free electrolyte, and the polyvinylidene fluoride (PVDF) swells, worsening the adhesion between the positive and negative electrodes. This reduces the adhesion between the positive electrode and the separator, increasing the risk of the positive electrode detaching. When the cell experiences vibration or other operating conditions, electrode detachment can easily lead to short circuits. In traditional top-mounted energy storage cells, the connection force between the tab and the cover assembly is much greater than the weight of the positive electrode and the forces are in the same direction, making these cells less prone to electrode detachment. However, in side-mounted energy storage cells, such as... Figure 3 , Figure 4 The diagram shown illustrates the situation before and after the cell plate falls off in the side-out electrode post. Because the connection force between the electrode tab and the cover plate assembly is not in the same direction as the gravity of the positive electrode plate, the electrode plate is very prone to falling off.

[0048] like Figure 5 As shown, to solve the problem of electrode shedding in side-mounted battery cells, this application proposes a battery cell including a housing 100, a first cover plate assembly 300, and an electrode assembly 200. The housing 100 has an opening at its side end; the first cover plate assembly 300 is disposed at the opening. The electrode assembly 200 includes a positive electrode 210, a separator 220, and a negative electrode 230 stacked along the width direction of the housing 100. The positive electrode 210 is connected to the separator 220 via a connecting structure 240.

[0049] During discharge, the positive electrode 210 releases energy by releasing lithium ions through the active material (migrating towards the negative electrode) and conducting electrons to the external circuit via the current collector. During charging, it receives electrons through the current collector, driving the active material to embed lithium ions, thus storing energy. During discharge, the negative electrode 230 receives energy by embedding lithium ions released from the positive electrode 210 through the active material and collecting electrons through the current collector. During charging, it releases lithium ions through the active material (migrating towards the positive electrode) and conducting electrons to the external circuit via the current collector, thus storing energy.

[0050] The electrode assembly 200 is disposed within the receiving space formed by the housing 100 and the first cover assembly 300. This receiving space provides a relatively stable environment for the electrochemical reaction, improving the reliability of the cell's charging and discharging process; and by providing mechanical protection for the electrode assembly 200, it reduces the possibility of electrolyte leakage. The housing 100 has an open side end. Taking a prismatic cell as an example, the length of the cell represents the dimension of the longer side of the bottom surface of the housing 100, corresponding to the length direction of the housing 100; the width of the cell represents the dimension of the shorter side of the bottom surface of the housing 100, corresponding to the width direction of the housing 100; the length direction and width direction of the housing 100 are perpendicular to each other; the height of the cell represents the dimension of the side perpendicular to the bottom surface of the housing 100, corresponding to the height direction of the housing 100; the height direction of the housing 100 is perpendicular to the bottom surface of the housing 100. The length, width, and height of the housing 100 correspond to the length, width, and height of the cell, respectively; the open end is formed on the side end face determined by the width and height of the cell. The positive electrode 210, the separator 220 and the negative electrode 230 of the electrode assembly 200 are stacked along the width direction of the housing 100. The deformation of the electrode assembly 200 is constrained by the inner wall of the housing 100 to reduce the risk of misalignment of the electrode assembly 200.

[0051] Understandably, the positive electrode 210, the separator 220 and the negative electrode 230 of the electrode assembly 200 are stacked along the width direction of the housing 100; wherein, the number of positive electrode sheets can be multiple, the number of negative electrode sheets can be multiple or one in succession; the number of separators can be multiple or one in succession. When there are multiple negative electrode plates, the separator can be one or more consecutive plates. Multiple positive electrode plates and multiple negative electrode plates are arranged alternately along the width direction of the shell, and one or more consecutive separators are disposed between adjacent positive and negative electrode plates. Alternatively, a single consecutive negative electrode plate is used, which is folded back and forth and forms multiple spacer layers along the width direction of the shell. When there are multiple separators, multiple positive electrode plates are disposed in adjacent spacer layers formed by the negative electrode plates, and multiple separators are disposed between adjacent positive and negative electrode plates. Alternatively, a single consecutive negative electrode plate is used, which is folded back and forth and forms multiple spacer layers along the width direction of the shell. When there is a single consecutive separator, the separator is folded synchronously in each spacer layer of the negative electrode plate, so that the upper and lower surfaces of the negative electrode plate are covered by the separator. Multiple positive electrode plates are disposed between adjacent separators, and the separators achieve insulation and isolation between the positive and negative electrodes and ion conduction.

[0052] The first cover plate assembly 300 is disposed at the opening of the housing 100. The positive electrode 210 and the negative electrode 230 are led out from the opening on the side of the housing through corresponding tabs. The tabs of the positive electrode 210 and the negative electrode 230 are respectively connected to the electrode structure (such as the electrode post or busbar) on the cover plate to realize the conduction of the internal current of the cell to the outside. For example, the opening direction intersects the direction of gravity. In the embodiment of this application, the positive electrode 210 is stably connected to the diaphragm 220 through the connecting structure 240, which can reduce the problem of electrode loosening caused by vibration, internal stress and other reasons, reduce the risk of electrode loosening and falling off, and further solve the short circuit problem caused by falling off, reduce the safety risk throughout the entire life cycle of the cell, and improve the stability and reliability of the overall performance of the cell. Placing the connection structure on the separator would prevent effective connection between the positive electrode and the separator due to the inability to determine the position of the positive electrode. By providing a connection structure 240, such as a connecting adhesive, on the positive electrode 210, the positive electrode 210 can be positioned and connected to the separator 220, achieving a stable connection between them. The positive electrode 210 is connected to the separator 220 through the connection structure 240 to form a unified structure. This also improves the overall structural stability of the electrode assembly 200, thereby increasing the overall structural strength of the cell, simplifying the structural design, reducing the use of other additional connection structures, and lowering production costs.

[0053] In one embodiment, the connection structure 240 is made of insulating adhesive.

[0054] The connecting structure 240 uses insulating adhesive, and may also use polymeric adhesive, such as a coated hot-melt polymer; for example, the polymeric adhesive may be, but is not limited to, ethylene-acrylic acid polymer or polyethylene-maleic acid copolymer resin; the specific connecting structure 240 can be selected according to actual needs, and is not limited here. The positive electrode 210 is connected to the separator 220 through the connecting structure 240, and can be effectively bonded to the separator 220 by hot pressing, in order to reduce the impact of electrolyte absorption by the separator 220 on the bonding effect between the positive electrode 210 and the separator 220.

[0055] like Figure 5 As shown, in one embodiment, the length of the negative electrode 230 along the height direction of the housing 100 is greater than the length of the positive electrode 210 along the height direction of the housing 100.

[0056] During charging, if the lithium ions extracted from the positive electrode are not fully embedded in the negative electrode, excess lithium ions will deposit on the surface of the negative electrode, potentially causing a short circuit between the positive and negative electrodes. The positive electrode 210, separator 220, and negative electrode 230 are stacked along the width direction of the housing 100. The width of the positive electrode 210 is determined by its length along the height direction of the housing 100, and similarly, the width of the negative electrode 230 is determined by its length along the height direction of the housing 100. The width direction W of the positive electrode 210 and negative electrode 230 corresponds to the height direction of the battery cell. The length of the positive electrode 210 is determined by its length along the length direction of the housing 100, and similarly, the length of the negative electrode 230 is determined by its length along the length direction of the housing 100. The length direction L of the positive electrode 210 and negative electrode 230 corresponds to the length direction of the battery cell. The length of the negative electrode 230 along the height direction of the housing 100 is greater than the length of the positive electrode 210 along the height direction of the housing 100, meaning the width of the negative electrode 230 is greater than the width of the positive electrode 210. This greater width ensures, to a certain extent, that the battery capacity of the negative electrode is greater than that of the positive electrode, allowing lithium ions to be fully absorbed by the negative electrode, reducing the risk of short circuits and extending battery life. Furthermore, it reduces the risk of misalignment caused by volume changes during charging and discharging, minimizing short circuits due to electrode displacement or detachment, and optimizing cell safety. Since the length of the negative electrode 230 along the height direction of the housing 100 is greater than the length of the positive electrode 210 along the height direction of the housing 100, the risk of the negative electrode 230 falling off is relatively small. Therefore, the risk of the positive electrode falling off is mainly reduced by setting the connection structure 240 on the positive electrode 210. Of course, in some other embodiments, in order to make the overall structure of the electrode assembly more stable, a connection structure can also be set between the negative electrode and the separator; this is not limited here.

[0057] In some embodiments, in order to further ensure that lithium ions can be fully received by the negative electrode and reduce the risk of short circuit, the length of the negative electrode 230 can be set to be greater than the length of the positive electrode 210.

[0058] For example, the length of the positive electrode 210 is 400mm to 600mm, and the length of the negative electrode 230 is 400mm to 600mm, with the length of the negative electrode 230 being greater than the length of the positive electrode 210. The width of the positive electrode 210 is 150mm to 250mm, and the width of the negative electrode 230 is 150mm to 250mm, with the width of the negative electrode 230 being greater than the width of the positive electrode 210. For instance, the length of the positive electrode 210 can be any value within the range of 400mm to 600mm, such as 400mm to 500mm, 500mm to 600mm, 400mm to 550mm, or 450mm to 600mm; it can also be any value within the range of 400mm to 600mm, such as 400mm, 450mm, 500mm, 550mm, or 600mm. The length of the negative electrode 230 can be 400mm to 500mm... The length of the negative electrode 230 is greater than the length of the positive electrode 210, and can be any value within the range of 400mm to 600mm, such as 500mm to 600mm, 400mm to 550mm, 450mm to 600mm, etc. The width of the positive electrode 210 can be any value within the range of 150mm to 250mm, such as 150mm to 200mm, 200mm to 250mm, 150mm to 180mm, or 180mm to 230mm; it can also be any value within the range of 150mm to 250mm, such as 150mm, 180mm, 200mm, 230mm, or 250mm. The width of the negative electrode 230 can be 150mm to 200mm, 200mm to 250mm. The width of the negative electrode 230 is greater than the width of the positive electrode 210, and can be any value within the range of 150mm to 250mm, such as ~250mm, 150mm to 180mm, 180mm to 230mm, etc.; the width of the negative electrode 230 can also be any value within the range of 150mm to 250mm, such as 150mm, 180mm, 200mm, 230mm, 250mm, etc.; no limitation is imposed here.

[0059] like Figure 6As shown, in one embodiment, the separator 220 is a single-layer membrane. The separator 220 is folded back and forth and forms multiple spacer layers 221 along the width direction of the housing 100. The positive electrode 210 and the negative electrode 230 are respectively disposed in adjacent spacer layers 221. The positive electrode 210, the negative electrode 230 and the separator 220 adopt a Z-stacking process. Compared with placing the separator 220 layer by layer between adjacent positive electrode 210 and negative electrode 230, the Z-stacking process achieves multi-layer isolation by using a single-layer continuously folded separator 220. This can reduce the cutting steps of the separator 220, increase the stacking speed, and reduce the risk of electrode (positive electrode 210, negative electrode 230) displacement and separator 220 misalignment. In this way, space utilization and assembly efficiency can also be improved, and the separator 220 can adsorb more electrolyte, so that ion transport is uninterrupted during charging and discharging.

[0060] like Figure 6 As shown, in one embodiment, the bottom of the positive electrode 210 is suspended relative to the inner bottom surface of the housing 100 along the height direction of the housing 100.

[0061] Understandably, the separator 220 wraps around the bottom of the negative electrode 230, while the bottom of the positive electrode 210 is not wrapped by the separator 220. The separator 220, by wrapping around the bottom of the negative electrode 230, can block the conductive path between the negative electrode 230 and the housing 100. In order for lithium ions to be fully received by the negative electrode, the length of the negative electrode 230 along the height direction of the housing 100 is greater than the length of the positive electrode 210 along the height direction of the housing 100. The bottom of the positive electrode 210 does not extend to be flush with the bottom of the negative electrode 230. In addition, the bottom of the positive electrode 210 is not wrapped by the separator 220, which causes the positive electrode 210 to be suspended relative to the inner bottom surface of the housing 100 along the height direction of the housing 100. This suspended arrangement can facilitate the containment of more electrolyte.

[0062] The design that the length of the negative electrode 230 along the height direction of the housing 100 is greater than the length of the positive electrode 210 along the height direction of the housing 100 allows lithium ions to be fully received by the negative electrode. The connection structure between the positive electrode 210 and the separator 220 achieves a stable connection between the positive electrode 210 and the separator 220, reducing the risk of short circuits caused by the positive electrode 210 falling off and optimizing safety. The suspended arrangement of the bottom of the positive electrode 210 relative to the inner bottom surface of the housing 100 accommodates more electrolyte, optimizing charge and discharge performance and extending battery cycle life. All of these measures are used to comprehensively improve battery performance.

[0063] like Figure 6 As shown, in one embodiment, there are multiple positive electrode plates 210, a negative electrode plate 230 is disposed between two adjacent positive electrode plates 210, and a separator 220 is disposed between adjacent positive electrode plates 210 and negative electrode plates 230.

[0064] For example, there can be multiple positive electrode plates, multiple negative electrode plates or one continuous negative electrode plate; there can be multiple separators or one continuous separator. When there are multiple positive and negative electrode plates, they are arranged sequentially along the width of the shell in the form of "positive electrode plate-negative electrode plate-positive electrode plate-negative electrode plate...", with one or more consecutive separators placed between adjacent positive and negative electrode plates. When there are multiple positive electrode plates and one consecutive negative electrode plate, the negative electrode plate is folded back and forth and forms multiple spacer layers along the width of the shell. When there are multiple separators, multiple positive electrode plates are placed in adjacent spacer layers formed by the negative electrode plates, and multiple separators are placed between adjacent positive and negative electrode plates. When there are multiple positive electrode plates, one consecutive negative electrode plate, and one consecutive separator, the negative electrode plate is folded back and forth and forms multiple spacer layers along the width of the shell. The separators are folded synchronously in each spacer layer of the negative electrode plate, so that the upper and lower surfaces of the negative electrode plate are covered by the separators. Multiple positive electrode plates are placed between adjacent separators, and the separators achieve insulation and ion conduction between the positive and negative electrodes.

[0065] Taking a lithium battery electrode assembly with multiple positive electrode plates 210 and multiple negative electrode plates 230, and a single continuous separator as an example, the separator 220 is folded back and forth and forms multiple spacer layers 221 along the width direction of the housing 100. The size of the spacer layers 221 formed by the separator 220 is adapted to the size of a single electrode plate (positive electrode plate 210, negative electrode plate 230). Multiple positive electrode plates 210 and multiple negative electrode plates 230 are respectively disposed in adjacent spacer layers 221. By alternatingly arranging multiple positive electrode plates 210 and multiple negative electrode plates 230, the total effective area for lithium-ion reaction can be increased, thereby improving the battery capacity. The separator 220 is disposed between adjacent positive electrode plates 210 and negative electrode plates 230. The separator 220 allows lithium ions to pass through and can block electron conduction between positive electrode plates 210 and negative electrode plates 230, avoiding short circuit problems and local overheating caused by short circuits, thus optimizing battery safety.

[0066] like Figure 5 As shown, in one embodiment, the connection structure 240 is disposed on the side of the positive electrode plate 210 away from the positive electrode tab 211.

[0067] The positive tab 211 serves as a conductive structure connecting the positive electrode 210 to the external circuit. If the connection structure 240 is placed on the positive tab 211, it will cover the connection area between the positive tab 211 and the external circuit. The connection structure 240 is made of insulating adhesive, and because the adhesive layer's insulation hinders the current conduction path, placing the connection structure 240 on the positive tab 211 will also affect the actual charging and discharging efficiency and may even cause localized overheating of the battery cell. Placing the connection structure 240 on the side of the positive electrode 210 away from the positive tab 211 can avoid the current conduction path of the positive electrode 210, thus ensuring a stable connection between the positive electrode 210 and the separator 220, solving the problem of electrode detachment, and ensuring smooth current conduction.

[0068] like Figure 5 As shown, by way of example, the connection structure 240 can be disposed on at least one peripheral side of the positive electrode plate 210 away from the positive electrode tab 211; it can also be disposed on at least one corner of the positive electrode plate 210 away from the positive electrode tab 211; or it can be disposed in the middle of the positive electrode plate 210. The connecting structure 240 uses a connecting adhesive. Coating the connecting structure 240 around the periphery of the positive electrode 210 reduces potential displacement of the positive electrode 210 during charging and discharging. It also isolates the positive electrode edge from the electrolyte and ensures a stable connection between the positive electrode 210 and the separator 220. Coating the connecting structure 240 at the corners of the positive electrode 210 reduces stress concentration at these corners, which can lead to unstable connections with the separator 220. Coating the connecting structure 240 around the periphery and corners of the positive electrode 210 ensures a stable connection between the positive electrode 210 and the separator 220 at the edges, reducing the risk of electrode detachment. Maintaining a gap between the positive electrode 210 and the separator 220 facilitates electrolyte entry and improves battery performance. Coating the connecting structure 240 in the center of the positive electrode 210 enhances the adhesion between the positive electrode 210 and the separator 220, further reducing the risk of electrode detachment.

[0069] like Figure 5 As shown, in some embodiments, the connection structure 240 is disposed on the upper side of the positive electrode 210.

[0070] The connection structure 240 is positioned on the upper edge or inactive region of the positive electrode 210, away from the positive electrode tab 211, thus avoiding the current conduction path of the positive electrode 210. This ensures a stable connection between the positive electrode 210 and the separator 220, preventing electrode detachment, while also ensuring smooth current flow. This arrangement also facilitates the entry of electrolyte into the gap between the positive electrode 210 and the separator 220, reducing obstruction to the contact between the active material and the electrolyte. A stable connection can be achieved simply by placing the connection structure 240 on the upper side of the positive electrode 210, reducing the number of connection structures required while maintaining stable connection and battery performance.

[0071] like Figure 5, Figure 6 As shown, for example, the connection structure 240 is disposed on at least one surface of the positive electrode 210.

[0072] In one embodiment, the connection structure 240 is disposed on both surfaces of the positive electrode 210.

[0073] The positive electrode 210 has two opposing sides that are in contact with the separator 220. Structural adhesive is applied to both sides of the positive electrode 210 and the separator 220. Compared to applying the connection structure 240 to only one side of the positive electrode 210, this can enhance the adhesion of the connection structure 240 and further optimize the connection effect between the two, reducing the risk of electrode detachment.

[0074] In addition to covering the connection structure 240 on both surfaces of the positive electrode 210, the connection structure can also be covered on at least one surface of the negative electrode that contacts the separator; the connection structure can be covered at the position where the separator contacts the positive electrode; or the connection structure can be covered at the position where the separator contacts the negative electrode. The specific configuration can be determined according to actual conditions and is not limited here.

[0075] like Figure 5 As shown, in one embodiment, the length of the connecting structure 240 is not less than 50% of the length of the positive electrode 210, the width of the connecting structure 240 is 1% to 3% of the width of the positive electrode 210, and the thickness of the connecting structure 240 is 30 μm to 80 μm.

[0076] For example, the length of the connecting structure 240 can be, but is not limited to, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% of the length of the positive electrode 210, or any other value not less than 50%; the width of the connecting structure 240 can be, but is not limited to, any value within the range of 1% to 3% of the width of the positive electrode 210, such as 1% to 2%, 2% to 3%, 1% to 1.5%, 1.5% to 2%, 1.5% to 2.5%, 1.5% to 3%, 2.5% to 3%; the width of the connecting structure 240 can also be any value within the range of 1% to 3% of the width of the positive electrode 210, such as 1%. The thickness of the connecting structure 240 can be any value within the range of 30μm to 80μm, such as 30μm to 50μm, 30μm to 55μm, 55μm to 70μm, 30μm to 60μm, 60μm to 80μm; or it can be any value within the range of 30μm to 80μm, such as 30μm, 40μm, 50μm, 55μm, 60μm, 70μm, 80μm; it is not limited here.

[0077] The coating length of the connecting structure 240 is not less than 50% of the length of the positive electrode 210, which ensures a stable and tight connection between the positive electrode 210 and the separator 220. When the length of the connecting structure 240 is greater than 80%, it may completely cover the edge area of ​​the positive electrode 210, resulting in excessive obstruction of the ion transport path and affecting the contact between the positive electrode 210 and the electrolyte. Therefore, the coating length of the connecting structure 240 can be limited to no more than 80% of the length of the positive electrode 210 to reduce the impact of the connecting structure 240 on the edge reactivity of the positive electrode. When the coating width of the connecting structure 240 is less than 1% of the width of the positive electrode 210, the positive electrode 210 may not be able to effectively adhere to the separator 220, and the positive electrode 210 may fall off. Setting the coating width of the connecting structure 240 to 1% to 3% of the width of the positive electrode 210 can also reduce the potential cost increase and waste caused by excessive coating width of the connecting structure 240.

[0078] The coating thickness of the connection structure 240 is 30μm to 80μm. If the coating thickness of the connection structure 240 is insufficient, the positive electrode 210 will fall off. If the coating thickness of the connection structure 240 is too thick, it will occupy a large space. The coating thickness of the connection structure 240 is 30μm to 80μm, which can be used to reduce the space occupied by the electrode assembly 200 while achieving a stable connection between the positive electrode 210 and the separator 220.

[0079] like Figure 7 As shown, in one embodiment, the first cover plate assembly 300 includes a cover plate body 310, a first electrode post 320, and a second electrode post 330. The first electrode post 320 is disposed on the cover plate body 310, and the second electrode post 330 is disposed on the cover plate body 310. The positive electrode plate 210 has a positive electrode tab 211, and the negative electrode plate 230 has a negative electrode tab 231. The positive electrode tab 211 of the positive electrode plate 210 is connected to the first electrode post 320, and the negative electrode tab 231 of the negative electrode plate 230 is connected to the second electrode post 330.

[0080] The first terminal 320 is the positive terminal, and the second terminal 330 is the negative terminal. Both the first terminal 320 and the second terminal 330 are located on the first cover plate assembly 300. There are multiple positive tabs 211 and multiple negative tabs 231. The positive tabs 211 of each positive electrode 210 are collected and connected to the first terminal 320 on the first cover plate assembly 300, and the multiple negative tabs 231 are collected and connected to the negative terminal on the first cover plate assembly 300. The centralized layout of the first terminal 320 and the second terminal 330 on the first cover plate assembly 300 shortens the connection path between the terminal and the tab, reduces internal resistance, and effectively saves space, achieving a compact design.

[0081] like Figure 8As shown, in one embodiment, the housing 100 has a bidirectional conduction structure with two openings: a first opening and a second opening. A first cover plate assembly 300 is disposed at the first opening. The battery cell also includes a second cover plate assembly 400 and a pressure relief structure 410. The second cover plate assembly 400 is disposed at the second opening, and the pressure relief structure 410 is disposed on the second cover plate assembly 400. The pressure relief structure 410 disposed on the second cover plate assembly 400 is separately disposed from the first terminal 320 and the second terminal 330 disposed on the first cover plate assembly 300, which can achieve directional pressure relief and reduce the risk of short circuit caused by electrolyte contact with the terminal during pressure relief, thereby improving safety. The pressure relief structure 410 can be, but is not limited to, a pressure relief valve or an explosion-proof valve. When the internal pressure of the battery cell exceeds a threshold due to thermal runaway or other reasons, the pressure relief structure 410 automatically opens to release gas, thereby reducing the potential risk of explosion.

[0082] In other embodiments, pressure relief structures 410 may be provided on the first cover plate assembly 300 and the second cover plate assembly 400 respectively to further optimize the pressure relief effect.

[0083] like Figure 8 As shown, a first cover plate assembly 300 is disposed at the first opening, and a second cover plate assembly 400 is disposed at the second opening. The first cover plate assembly 300 and the second cover plate assembly 400 can be connected and fixed to the housing 100 by means of laser welding, bonding, or other methods. By sealing the openings of the housing 100 with the first cover plate assembly 300 and the second cover plate assembly 400 respectively, a sealed receiving space can be formed, in which the electrode assembly 200 is installed. The first opening and the second opening can be disposed at different positions on the housing 100. In some embodiments, the first opening and the second opening are disposed opposite to each other to distribute the force on the housing 100 and reduce the risk of deformation.

[0084] At least one of the aforementioned first cover plate assembly 300 and second cover plate assembly 400 may be provided with an injection hole 311. For example, the injection hole 311 is provided on the cover plate body 310 of the first cover plate assembly 300. The number of injection holes 311 is one or more. When multiple injection holes 311 are provided, increasing the number of injection holes 311 can effectively improve the injection efficiency and make the electrolyte distribution more uniform.

[0085] In one embodiment, the battery cell further includes a bottom support plate (not shown), which is disposed between the lower end face of the electrode assembly 200 and the inner bottom face of the housing 100.

[0086] A base plate is positioned between the lower end face of the electrode assembly 200 and the inner bottom surface of the housing 100. It provides stable support for the electrode assembly 200, bearing its weight and reducing the sagging and displacement of the positive electrode 210 and negative electrode 230 due to gravity. It further reduces the possibility of the positive electrode 210 and negative electrode 230 falling off, resulting in a more compact overall internal structure of the battery cell. The base plate can be made of PE (polyethylene), PVC (polyvinyl chloride), or other insulating materials. It also serves to separate the electrode assembly 200 from the housing 100 in the event of electrode falling off, thus mitigating the risk of short circuits caused by direct contact between the positive electrode 210 and negative electrode 230 and the inner bottom surface of the metal housing 100.

[0087] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A battery cell, characterized in that, include: A housing, wherein the side ends of the housing are open; A first cover assembly is disposed at the opening; An electrode assembly, comprising a positive electrode, a separator, and a negative electrode stacked along the width direction of the housing; The positive electrode is connected to the separator via a connection structure.

2. The battery cell as described in claim 1, characterized in that, The first cover plate assembly includes: Cover plate body; The first pole post is disposed on the cover plate body; The second pole post is disposed on the cover plate body; The positive electrode has a positive tab and the negative electrode has a negative tab. The positive tab of the positive electrode is connected to the first terminal, and the negative tab of the negative electrode is connected to the second terminal.

3. The battery cell as described in claim 1, characterized in that, The length of the negative electrode along the height direction of the housing is greater than the length of the positive electrode along the height direction of the housing.

4. The battery cell as described in claim 1, characterized in that, The diaphragm is a single-layer membrane, which is folded back and forth and forms multiple spacer layers along the width direction of the shell. The positive electrode and the negative electrode are respectively disposed in adjacent spacer layers.

5. The battery cell as described in claim 4, characterized in that, Along the height direction of the housing, the bottom of the positive electrode is suspended relative to the inner bottom surface of the housing.

6. The battery cell as described in claim 1, characterized in that, The number of positive electrode plates is multiple, and the negative electrode plate is disposed between two adjacent positive electrode plates. The separator is disposed between adjacent positive electrode plates and the negative electrode plate.

7. The battery cell as described in claim 1, characterized in that, The connection structure is located on the side of the positive electrode plate away from the positive electrode tab.

8. The battery cell as described in claim 1, characterized in that, The connection structure is disposed on the upper side of the positive electrode plate.

9. The battery cell as described in claim 1, characterized in that, The connection structure is covered on both sides of the positive electrode sheet.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The length of the connecting structure is not less than 50% of the length of the positive electrode sheet, the width of the connecting structure is 1% to 3% of the width of the positive electrode sheet, and the thickness of the connecting structure is 30μm to 80μm.

11. The battery cell according to any one of claims 1 to 9, characterized in that, The connection structure uses insulating adhesive.

12. The battery cell according to any one of claims 1 to 9, characterized in that, The battery cell also includes a bottom support plate, which is disposed between the lower end face of the electrode assembly and the inner bottom face of the housing.

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