Battery cell, battery pack, and electric device

Abstract

The application discloses a battery monomer, a battery pack and a power utilization device. The battery monomer comprises a battery cell, a plastic package and a protection circuit module. The battery cell is divided into a battery cell main body, a tab and a top sealing part. The tab is located in the battery cell main body and extends from the output side of the battery cell main body. The top sealing part is located at the output side of the battery cell main body and covers the tab. One side of the top sealing part in the thickness direction of the top sealing part is provided with a window, and a part of the tab is exposed to the window. The protection circuit module is located at the output side of the battery cell main body and is parallel to the top sealing part. The protection circuit module is connected with the exposed part of the tab. The plastic package is located at the output side of the battery cell main body and wraps the top sealing part and the protection circuit module. In this way, the tab does not extend outward from the top sealing part, so that the exposed height is not generated. Meanwhile, the thickness of the protection circuit module is not stacked on the top sealing part, so that more design space is left for the battery cell main body under the condition that the height of the battery monomer is determined, and the capacity of the single battery monomer is improved.

Description

Technical Field

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

[0002] A battery pack is a unit that combines multiple battery cells in series, parallel, or mixed connections, and is equipped with necessary management systems (such as a BMS), protection circuits, and cooling systems to form a stable power supply. Battery packs are widely used in electric vehicles, energy storage systems, portable electronic devices, and other fields.

[0003] Battery cells are the basic units of a battery pack, responsible for storing and releasing energy. They can be cylindrical, prismatic, or pouch-type, with the appropriate type chosen based on application requirements.

[0004] In existing battery cells, the cell tabs are usually exposed, extending from the top seal on the output side of the cell body. The exposed tabs are then connected to the protection circuit module (PCM). The protection circuit module needs to be separately arranged on the side of the exposed tabs away from the cell body. The combination of the protection circuit module and the exposed tabs occupies a large height on the output side of the cell body. When the total height of the battery cell is limited, the larger the total height occupied by the exposed tabs and the protection circuit module, the smaller the effective height of the cell body (active material area), resulting in a decrease in the battery cell capacity. Utility Model Content

[0005] The purpose of this application is to provide a battery cell, a battery pack, and an electrical device that can leave more design space for the main body of the battery cell with a fixed height, thereby increasing the capacity of a single battery cell and the energy density of the battery pack.

[0006] The embodiments of this application can be implemented as follows: In a first aspect, this application provides an implementation of a battery cell, which includes a battery cell, a plastic encapsulation, and a protection circuit module; The battery cell is divided into a battery cell body, a tab, and a top seal. The tab is located inside the battery cell body and extends from the output side of the battery cell body. The top seal is located on the output side of the battery cell body and covers the tab. The top seal has a window on one side in its thickness direction, and a part of the tab is exposed in the window. The protection circuit module is located on the output side of the main body of the battery cell and is parallel to the top seal. The protection circuit module is connected to the exposed part of the electrode tab. The plastic encapsulation is located on the output side of the main body of the battery cell and wraps around the top seal and the protection circuit module.

[0007] In the above-described embodiment, by designing the tabs to be enclosed by the top seal, the tabs do not protrude outwards from the top seal, thus eliminating exposed height. Simultaneously, by arranging the protection circuit module and the top seal side-by-side on the output side of the cell body, the thickness of the protection circuit module does not overlap with the top seal, avoiding the increased height of a stacked layout. This allows for greater design space in the cell body with a fixed battery cell height, thereby increasing the capacity of a single battery cell. A window is provided in the top seal to expose the tabs, ensuring proper connection between the exposed tabs and the protection circuit module for current transmission.

[0008] In an optional embodiment, the battery cell further includes a conductive sheet, which is fixed to the side of the protection circuit module away from the output side of the cell body, and the conductive sheet is connected to the exposed portion of the tab.

[0009] In the above implementation, a conductive sheet is used as the connection path between the area of ​​the electrode exposed through the window and the protection circuit module, thereby realizing the electrical connection between the electrode and the protection circuit module and accommodating the height difference between the window and the protection circuit module.

[0010] In an optional embodiment, the conductive sheet and the tab are connected by a bonding wire.

[0011] The above-described embodiment uses wire bonding to connect the conductive sheet and the tab with a wire. This process is very suitable for the compact space of the top sealing window area because of its small and low solder joints and high adaptability. Moreover, the metal wire has a certain degree of flexibility, which can adapt to the small positional deviation between the conductive sheet and the window, reducing the positioning requirements of both the conductive sheet and the tab.

[0012] In an optional embodiment, the conductive sheet includes a connecting plate and a connecting lug connected at an angle. The connecting plate is fixed to the side of the protection circuit module away from the output side of the battery cell body. The connecting lug is aligned with and fits against the top seal. The connecting lug is connected to the electrode lug through the bonding wire.

[0013] The above-described implementation achieves coplanar contact between the connecting lugs and electrode tabs of the conductive sheet through the angled design. During wire bonding, only a small height needs to be crossed, and the wire length can be shortened. At the same time, it avoids mechanical stress breakage caused by excessive height difference between the two ends of the wire being squeezed by the outer plastic encapsulation or by the wire being too short. Meanwhile, the connecting plate can fully contact the protection circuit module, ensuring the area between the two.

[0014] In an optional embodiment, the tab has two or more windows corresponding to the thickness direction of the top seal, and all the windows corresponding to each tab are connected to a connecting ear.

[0015] In the above-described implementation, multi-window wire bonding allows the current from the tabs to be conducted to the connecting ears through multiple paths, reducing the risk of heat concentration in single-window wire bonding. Furthermore, even if one wire breaks due to fatigue, the remaining wires can still maintain conductivity, improving the fault tolerance of the battery cell. Additionally, the dispersed wire bonding joints reduce localized heat density, preventing aging of the top seal material due to single-point overheating.

[0016] In an optional embodiment, the connecting ear and the electrode ear are disposed opposite each other in the thickness direction of the top seal, and each connecting ear is distributed between two adjacent windows.

[0017] The above-described embodiments can make the wire bonding distribution more uniform, while ensuring a more uniform distribution of stress and current.

[0018] In an optional embodiment, the surface of the bonding wire is covered with an anti-corrosion layer, and the bonding wire is fixed to the conductive sheet by adhesive.

[0019] The above-described implementation method ensures the stability and reliability of the connection between the welding wire and the electrode tab and conductive sheet by applying adhesive, and also provides insulation. The anti-corrosion layer provides moisture and corrosion protection, thereby improving the long-term stability of the battery cell in harsh environments.

[0020] In an optional embodiment, the inner diameter of the window is 0.1~1.4mm.

[0021] The above-described implementation method can be adapted to solder wires of different thicknesses.

[0022] In an alternative embodiment, the inner diameter of the window gradually decreases from the end of the window near the tab to the end away from the window.

[0023] The above-described embodiments can make the inner side of the window narrower, and the window presents a roughly funnel-shaped structure, which is convenient for processing and welding, and can also guide the molding material to be stuck on the outside of the top seal during the molding process, so as to prevent the tab and the molding material from directly contacting each other, and prevent micro short circuits or local leakage caused by the molding material directly contacting the tab surface.

[0024] In an optional implementation, the protection circuit module and the battery cell body are fixed together by adhesive application or integral injection molding.

[0025] The above-described implementation method allows for flexible glue application and facilitates later maintenance or replacement; it also achieves excellent sealing and insulation. The one-piece injection molding method enhances overall structural strength and waterproof / dustproof ratings; it reduces assembly steps and improves production efficiency.

[0026] Secondly, this application provides an embodiment of a battery pack, which includes the battery cells described in any of the above embodiments.

[0027] In the above embodiments, since the battery cells included in any of the aforementioned embodiments have higher capacity, the battery pack also has higher energy density.

[0028] Thirdly, this application provides an embodiment of an electrical device, which includes a battery cell or a battery pack as described in any of the above embodiments.

[0029] The above embodiments, since they include the battery packs or battery cells of the aforementioned embodiments, have battery cells with higher capacity or battery packs with higher energy density, and can be applied to different products according to actual needs, such as applying battery cells to mobile phones and applying battery packs to automobiles. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a front view of a single battery cell according to an embodiment of this application; Figure 2 This is a side view of a single battery cell according to an embodiment of this application; Figure 3 for Figure 1 and Figure 2 Front view of the battery cell; Figure 4 for Figure 1 and Figure 2 Side view of the battery cell; Figure 5 for Figure 1 and Figure 2 Front view of the combined structure of the battery cell, protection circuit module, and conductive sheet; Figure 6 for Figure 1 and Figure 2 Side view of the combined structure of the battery cell, protection circuit module and conductive sheet.

[0032] Icons: 10-Battery cell; 11-Battery cell body; 12-Top seal; 120-Window; 20-Protection circuit module; 30-Conductive sheet; 31-Connecting plate; 32-Connecting ear; 40-Plastic seal; 50-Glue; 60-Wire bonding; 70-Electrical tab; 71-Positive electrode tab; 72-Negative electrode tab. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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 some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0038] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" 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 application based on the specific circumstances.

[0039] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] This application discloses a battery cell, which may be a lithium-ion battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc. The embodiments of this application are not limited to this.

[0041] Battery cells can be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited to this. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, cuboid / square battery cells, and pouch battery cells, and the embodiments of this application are not limited to this either.

[0042] refer to Figure 1 and Figure 2 The battery cell 10 is divided into a battery cell body 11, a tab 70, and a top seal 12; The main body of the battery cell 11, as the energy core of the battery cell 10, mainly relies on the movement of metal ions between the positive and negative electrode plates to function. The main body of the battery cell 11 includes active components such as positive electrode plates, negative electrode plates, separator, and electrolyte. Its volume (height / length / thickness) directly determines the amount of active material loaded and is the "carrier" of battery capacity—the larger the volume (within the limit of the total size of the single cell), the higher the capacity.

[0043] The positive electrode sheet includes a positive current collector and a positive active material layer, the positive active material layer being coated on the surface of the positive current collector; the positive current collector includes a positive current collection section and a positive electrode tab 71 connected to the positive current collection section, the positive current collection section being coated with the positive active material layer, and the positive electrode tab 71 not being coated with the positive active material layer. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.

[0044] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer being coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode current collection section and a negative electrode tab 72 connected to the negative electrode current collection section. The negative electrode current collection section is coated with the negative electrode active material layer, while the negative electrode tab 72 is not coated with the negative electrode active material layer. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0045] The tabs 70 (positive tab 71 and negative tab 72) are located inside the cell body 11 and extend from the output side of the cell body 11. The tabs 70 mainly serve as conductive bridges connecting the internal electrodes of the cell body 11 (positive tab 71 connects to the positive electrode plate, and negative tab 72 connects to the negative electrode plate) and external circuits (such as the protection circuit module 20). They are usually metal sheets (such as aluminum, copper or composite materials) and need to have low resistance and high conductivity.

[0046] The output side of the battery cell body 11, which is the side that external circuits and devices need to be connected to, is usually the side of the battery cell body 11 in the height direction.

[0047] The top seal 12 is located on the output side of the cell body 11 and covers the tab 70. Therefore, the top seal 12 is a sealing structure on the output side of the cell 10. Its core function is to seal the cell body 11, prevent electrolyte leakage, isolate air, and fix the tab 70, limiting its position and preventing short circuits caused by shaking. In addition, by covering the tab 70 with the top seal 12, the tab 70 can be transformed from the traditional structure where it extends outward from the top seal 12. This design, in which the tab 70 is completely covered by the top seal 12, ensures that the tab 70 does not have any exposed height. Only the height of the top seal 12 itself is retained on the output side of the cell body 11, leaving space for the cell body 11.

[0048] Among them, reference Figure 3 and Figure 4 The top cover 12 has a window 120 on one side in the thickness direction, through which the tab 70 is exposed; the window 120 of the top cover 12 can expose the tab 70 so that the exposed part of the tab 70 can be connected to the protection circuit module 20.

[0049] The protection circuit module 20 is located on the output side of the cell body 11 and is parallel to the top seal 12; The plastic seal 40 is located on the output side of the cell body 11 and wraps the top seal 12 and the protection circuit module 20. It can fix the relative position of the two (prevent displacement or connection breakage caused by vibration and impact) and isolate external moisture and dust, thus improving the environmental adaptability of the battery.

[0050] As described above, by designing the tab 70 to be enclosed by the top seal 12, the tab 70 will not protrude outward from the top seal 12, thus eliminating any exposed height. Simultaneously, by arranging the protection circuit module 20 and the top seal 12 side-by-side on the output side of the cell body 11, the thickness of the protection circuit module 20 will not overlap with the top seal 12, avoiding the increased height of the stacked layout. This allows for greater design space in the cell body 11 with a fixed battery cell height, thereby increasing the capacity of a single battery cell. A window 120 is provided in the top seal 12 to expose the tab 70, ensuring proper connection between the tab 70 and the protection circuit module 20 for current transmission.

[0051] It is understandable that since the tab 70 is divided into a positive tab 71 and a negative tab 72, at least one window 120 will be provided on the top seal 12 in the thickness direction corresponding to both the positive tab 71 and the negative tab 72, so as to ensure the continuity of the circuit.

[0052] The area of ​​the tab 70 exposed through the window 120 (i.e., the area used to connect with the protection circuit module 20) can be locally deoxidized (e.g., laser cleaning) to remove the oxide layer (oxide film of aluminum tab, oxide layer of copper tab) in that area, ensuring low-resistance connection after subsequent window opening; while the non-connection area can retain the oxide layer, thereby enhancing the adhesion to the top seal 12 layers.

[0053] The area of ​​the top seal 12 covering the tab 70 can be sealed using a gradient heat sealing process. This means that for the location of the tab 70 (the area with the metal foreign object), the heat sealing pressure is appropriately increased and the heat sealing time is extended to ensure that the sealing layer (such as the CPP layer) around the tab 70 is completely melted and fills the gap between the tab 70 and the material of the top seal 12, forming a "gapless seal" to prevent electrolyte leakage from the gap between the tab 70 and the top seal 12.

[0054] The end of the tab 70 (i.e. the end of the tab 70 away from the main body of the cell 11) and the top edge of the top seal 12 (the side away from the main body of the cell 11) need to reserve a certain height as a pure sealing area, so as to form a safety sealing strip of the top seal 12. Even if there are minor defects near the tab 70 due to process fluctuations, the pure sealing area can still ensure the overall sealing performance.

[0055] refer to Figures 1 to 4 In this embodiment, the battery cell also includes a conductive sheet 30, which is fixed on the side of the protection circuit module 20 away from the output side of the cell body 11, and the conductive sheet 30 is connected to the exposed part of the tab 70.

[0056] In this way, the conductive sheet 30 serves as the connection path between the area of ​​the tab 70 exposed through the window 120 and the protection circuit module 20, thereby realizing the electrical connection between the tab 70 and the protection circuit module 20 and accommodating the height difference between the window 120 and the protection circuit module 20.

[0057] The conductive sheet 30 is made of a material with high conductivity and low rigidity, such as nickel or copper-nickel composite material, which not only reduces electrical loss but also facilitates processing.

[0058] In detail, the protection circuit module 20, the conductive sheet 30, and the tab 70 are connected by wire bonding (such as ultrasonic gold / aluminum wire bonding). That is, the conductive sheet 30 and the tab 70 are connected by a bonding wire 60. This process is very suitable for the compact space of the window area of ​​the top seal 12 due to its small solder joints, low height, and strong adaptability. Moreover, the metal bonding wire 60 has a certain degree of flexibility and can adapt to the small positional deviation between the conductive sheet 30 and the window 120, reducing the positioning requirements of the conductive sheet 30 and the tab 70.

[0059] It should be noted that, depending on the material of the tab 70, the metal bonding wire 60 can be made of the same material to avoid electrochemical corrosion during welding of dissimilar metals. For example, if the tab 70 is made of aluminum, then the metal bonding wire 60 will be made of aluminum wire; if the tab 70 is made of copper, then copper wire can be used. Of course, aluminum wire can also be used, as aluminum is inexpensive and can reduce the overall cost of the battery cell.

[0060] In this embodiment, reference Figure 5 and Figure 6 The conductive sheet 30 is generally L-shaped. The conductive sheet 30 includes a connecting plate 31 and a connecting ear 32 connected at an angle. The connecting plate 31 is fixed on the side of the protection circuit module 20 away from the output side of the battery cell body 11. The connecting ear 32 is aligned and attached to the top seal 12. The connecting ear 32 is welded to the electrode ear 70 through the window 120.

[0061] In this way, the angled design allows the connecting lug 32 of the conductive sheet 30 to be in contact with the electrode 70 on the same plane. When bonding wires, only a small height needs to be crossed, and the length of the bonding wire 60 can be shortened. At the same time, it avoids mechanical stress breakage caused by excessive height difference between the two ends of the bonding wire 60 being squeezed by the outer plastic encapsulation 40 or being too short. Meanwhile, the connecting plate 31 can fully contact the protection circuit module 20, ensuring the area between the two.

[0062] The connecting ear 32 can be bonded and fixed to the surface of the top seal 12 with a high-temperature resistant adhesive (such as epoxy adhesive). The adhesive layer should avoid the wire bonding area (for example, apply adhesive only to the edge of the connecting ear 32) to ensure a stable fit without shaking, and to not affect the metal contact during wire bonding.

[0063] The angle between the connecting ear 32 and the connecting plate 31 is approximately 90°, or it can be close to 90° but with a slight error, such as 88~92°, so as to ensure that the connecting plate 31 and the connecting ear 32 are in contact with the plane of the protection circuit module 20 and the top seal 12 respectively.

[0064] The wire bonding area of ​​the connector ear 32 can be roughened and deoxidized. That is, a tiny bump and groove can be formed on the surface of the connector ear 32 by etching processes such as laser micro-etching, thereby increasing the contact area of ​​wire bonding and improving the connection reliability of the electrode 70 and the connector ear 32. At the same time, plasma cleaning can be used to remove the oxide layer (such as nickel oxide layer, copper oxide layer) in the wire bonding area of ​​the connector ear 32, reducing the wire bonding contact resistance.

[0065] The connecting plate 31 can be used to form a stable connection with the protection circuit module 20 by means of surface mount technology, welding, pressing, screw fixing or embedding injection molding.

[0066] Of course, in some embodiments, the conductive sheet 30 may not adopt an L-shaped structure, such as a Z-shaped, stepped, or arc-shaped structure with local planar structure, as long as it can ensure that it has a planar area to fit with the top sealing part 12.

[0067] Continue to refer to Figure 1 , Figure 3 and Figure 5 The tab 70 has two or more windows 120 in the thickness direction of the top seal 12. All windows 120 corresponding to each tab 70 are connected to a connecting ear 32. That is, the positive tab 71 and the negative tab 72 each have at least two windows 120 in the thickness direction of the top seal 12.

[0068] This multi-window 120 wire bonding allows the current from the tab 70 to be conducted to the connecting ear 32 through multiple paths, reducing the risk of heat concentration in a single-window 120 wire bonding. Moreover, even if one of the bonding wires 60 breaks due to fatigue, the remaining bonding wires 60 can still maintain conductivity, improving the fault tolerance of the battery cell. In addition, the dispersed wire bonding joints can reduce local heat density and avoid aging of the top seal 12 material due to single-point overheating.

[0069] The connecting ear 32 and the pole ear 70 are opposite each other in the thickness direction of the top seal 12, and each connecting ear 32 is distributed between two adjacent windows 120.

[0070] This allows for a more uniform wire distribution, while also ensuring a more uniform distribution of stress and current.

[0071] For example, in the illustrated embodiment, the conductive sheet 30 has two parallel connecting ears 32, which correspond to two electrodes 70 (i.e., positive electrode 71 and negative electrode 72). Each electrode 70 is exposed through two windows 120, and the individual connecting ears 32 are located between these two windows 120, achieving a symmetrical distribution. This disperses the current conduction path of the electrode 70 across the two windows 120. Furthermore, it avoids the problems caused by varying wire lengths of the bonding wires 60, such as long wires being prone to slack, short wires being prone to breakage, and long wires having high circuit resistance while short wires have low resistance.

[0072] In some embodiments not shown, each connecting tab 32 may be distributed on the same side of all windows 120 corresponding to a tab 70, in which case a single tab 70 may correspond to one or more windows 120. Alternatively, a single tab 70 may be exposed and connected to the conductive sheet 30 through a single window 120.

[0073] Of course, it is understandable that, in addition to wire bonding, the area of ​​the tab 70 exposed through the window 120 can also be connected to the conductive sheet 30 by laser welding, ultrasonic welding (sheet / block welding), resistance welding, brazing, riveting (with conductive adhesive assistance), etc.

[0074] For example, laser welding uses a high-energy-density laser beam focused on the contact area between the tab 70 and the conductive sheet 30, causing the local material to melt instantly and cool to form a fusion joint. Ultrasonic welding differs from wire bonding in that it involves stacking the tab 70 and the conductive sheet 30, then using ultrasonic vibration (high-frequency mechanical vibration) to cause plastic deformation of the metal at the contact surface, breaking down the surface oxide layer and forming a metallurgical bond. Resistance welding applies pressure to the contact point between the tab 70 and the conductive sheet 30 using electrodes, while simultaneously applying a large current. The contact resistance of the contact surface generates heat, causing the local metal to melt and form a weld nugget, which then cools to form a connection. Brazing uses a filler metal with a melting point lower than that of the tab 70 / conductive sheet 30 (such as tin-based or silver-based filler metal). Heating melts the filler metal and wets the two connecting surfaces, which then cools to form a metallurgical bond. Riveting uses methods such as press riveting to achieve tight contact between the tab 70 and the conductive sheet 30, while simultaneously applying conductive adhesive (such as silver-based or copper-based conductive adhesive) to the contact surface to reduce contact resistance and enhance connection stability.

[0075] It should also be noted that in some embodiments not shown, the conductive sheet 30 may not be provided, and the exposed area of ​​the tab 70 may be connected to the protection circuit module 20 directly through the window 120 by wire bonding.

[0076] After wire bonding, the exposed parts of the wires need to be coated with adhesive and treated with anti-corrosion agents. Specifically, the surface of the wire 60 is covered with an anti-corrosion layer, and the wire 60 is fixed to the conductive sheet 30 with adhesive. This adhesive fixation ensures the stable and reliable connection between the wire 60 and the tab 70 and conductive sheet 30, and also provides insulation. The anti-corrosion layer provides moisture and corrosion protection, thereby improving the long-term stability of the battery cell in harsh environments.

[0077] The process of applying adhesive can use high-reliability silicone, epoxy resin, or polyurethane sealant for partial or complete encapsulation. The adhesive layer covers the solder joint and the root of the solder wire 60 to prevent the solder wire 60 from breaking due to vibration or stress.

[0078] Corrosion protection can be achieved by plating or oxidizing the surface of the wire, such as nickel plating on copper wire or anodizing aluminum wire to form an oxide film, thereby improving its resistance to electrochemical corrosion. Alternatively, after welding, plasma cleaning can be used to remove weld slag and oxide layer, followed immediately by applying an ultra-thin anti-corrosion layer, such as a fluorocarbon coating, and then applying adhesive.

[0079] The wire diameter of the 60mm bonding wire can be configured according to the application scenario. For example, in low-current scenarios (such as consumer batteries, continuous current ≤1A), 0.10-0.15mm aluminum wire can be selected (aluminum wire is low in cost and compatible with aluminum tabs 70), with a single wire current carrying capacity of 0.8-1.5A, meeting the requirements and having a thin wire body (suitable for small spaces with windows). In medium-current scenarios (such as energy storage batteries, continuous current 1-5A), 0.18-0.25mm aluminum wire or 0.15-0.20mm copper wire can be selected (copper wire has better conductivity and a current carrying capacity 30% higher than aluminum wire of the same diameter), with a single wire current carrying capacity of 1.8-5A. In high-current scenarios (such as power batteries, continuous current 5-10A), 0.30-0.40mm copper wire (nickel-plated for oxidation prevention) can be selected, with a single wire current carrying capacity of 6-10A.

[0080] From the end of window 120 closest to tab 70 to the end furthest from window 120, the inner diameter of window 120 gradually decreases. This results in a wider outer side and a narrower inner side for window 120, giving it a roughly funnel-shaped structure. This facilitates processing and wire bonding, and during the encapsulation process, it guides the encapsulation material 40 to be held in place on the outer side of the top seal 12, preventing it from extending further inward. This avoids direct contact between tab 70 and encapsulation material, preventing micro-short circuits or localized leakage caused by direct contact between encapsulation material 40 and tab 70 surface. Additionally, it helps in the positioning and fixation of the bonding wire 60 within window 120.

[0081] When processing window 120, laser cutting technology can be used, such as ultraviolet laser (wavelength 355nm), with a cutting accuracy of ±0.05mm and an edge roughness Ra≤0.8μm, ensuring a smooth transition section without burrs and avoiding exposure of the aluminum layer or scratches on the plastic seal 40 film. The cutting path should be continuous from the outside to the inside to ensure a uniform slope. After laser cutting, the edges of window 120 (especially the inner closing end, i.e., the end with the smaller inner diameter) need to be reinforced with insulation, for example, by coating a layer of high-temperature resistant insulating adhesive (such as polyimide adhesive) to cover the potentially exposed top seal 12 aluminum layer (soft-pack battery cell 10), which not only prevents short circuits between the aluminum layer and the tab 70, but also further reduces the effective space at the inner closing end (enhancing the blocking effect on the plastic seal 40 film).

[0082] The inner diameter of window 120 is 0.1~1.4mm to accommodate welding wires 60 of different thicknesses.

[0083] Of course, the window 120 can also be in other shapes. For example, if the bonding wire 60 is thin, a round hole can be used directly, as long as the inner diameter of the window 120 can prevent the molding material 40 from contacting the tab 70 during the molding process.

[0084] The protection circuit module 20 and the battery cell body 11 are fixed together by adhesive application or integral injection molding. Adhesive application is flexible and facilitates later maintenance or replacement, while achieving good sealing and insulation. Integral injection molding can improve the overall structural strength and waterproof and dustproof rating, reduce assembly steps, and improve production efficiency.

[0085] The molding materials can be epoxy resin, polyurethane, silicone, thermoplastic conformal coating, etc., and molding 40 can be achieved by injection molding, potting, etc.

[0086] The adhesive 50 used to fix the protection circuit module 20 and the battery cell body 11 can be made of epoxy resin, polyurethane or silicone, etc., which have good insulation, corrosion resistance and structural strength.

[0087] Of course, in some embodiments, the protection circuit module 20 may also be achieved by thermoforming, mechanical snap-fit ​​connection, or embedded packaging, etc.

[0088] The manufacturing process of the battery cell in this application embodiment is roughly exemplified as follows: 1. The top seal 12 of the battery cell 10 does not protrude from the tab 70. A window is made in the top seal 12. The shape of the window is not limited. The window adopts an outer-larger-inner-smaller method to create a... Figure 3 and Figure 4 The structure.

[0089] 2. Fix the protection circuit module 20 to the output side of the battery cell 10 using glue. Fix the conductive sheet 30 to the output side of the protection circuit module 20. Simultaneously, align and tighten the connecting ears 32 of both the protection circuit module 20 and the conductive sheet 30 with the top seal 12. The connecting ears 32 can be located on the left, right, or center of the opening in the top seal 12 of the battery cell 10. Figure 5 and Figure 6 The structure.

[0090] 3. The tab 70 is wire-welded to the tab 70 exposed by the window 120 of the top seal 12. The size and type of the wire can be set according to the current. After wire bonding, the wire is fixed with glue and protected against corrosion. Then, the head is injection molded to improve reliability, thus manufacturing the product. Figure 1 and Figure 2 The structure shown.

[0091] This application also discloses a battery pack, which includes a housing and multiple battery cells as described above. Each battery cell can be directly housed in the housing in a matrix arrangement to form a module-less battery pack. Alternatively, each battery cell can be combined into multiple battery modules, and then the multiple battery modules can be housed in the housing. Since the battery cells have higher capacity, the battery pack also has higher energy density.

[0092] This application also discloses an electrical device that includes the battery pack or battery cell of the above embodiments, and thus also has the corresponding structure and beneficial effects. The battery cell has a higher capacity, and the battery pack has a higher energy density. The battery pack or battery cell can be flexibly selected according to different products.

[0093] The electrical equipment can be electronic devices such as mobile phones and tablets, or electric vehicles such as vehicles. This application does not impose any special restrictions on the aforementioned electrical equipment.

[0094] In summary, this application discloses a battery cell, a battery pack, and an electrical device. By designing the tab 70 to be enclosed by the top seal 12, the tab 70 does not protrude outward from the top seal 12, thus eliminating exposed height. Simultaneously, the protection circuit module 20 and the top seal 12 are arranged side-by-side on the output side of the cell body 11, preventing the thickness of the protection circuit module 20 from stacking onto the top seal 12. This avoids the increased height of a stacked layout, leaving more design space for the cell body 11 with a fixed battery cell height, thereby increasing the capacity of a single battery cell. A window 120 is provided in the top seal 12 to expose the tab 70, ensuring proper connection between the tab 70 and the protection circuit module 20 for current transmission.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, Includes battery cell (10), plastic encapsulation (40) and protection circuit module (20); The battery cell (10) is divided into a battery cell body (11), a tab (70) and a top seal (12). The tab (70) is located inside the battery cell body (11) and extends from the output side of the battery cell body (11). The top seal (12) is located on the output side of the battery cell body (11) and covers the tab (70). The top seal (12) has a window (120) on one side in its thickness direction, and a part of the tab (70) is exposed in the window (120). The protection circuit module (20) is located on the output side of the cell body (11) and is parallel to the top seal (12). The protection circuit module (20) is connected to the exposed part of the tab (70). The plastic seal (40) is located on the output side of the cell body (11) and wraps the top seal (12) and the protection circuit module (20).

2. The battery cell according to claim 1, characterized in that, The battery cell also includes a conductive sheet (30), which is fixed to the side of the protection circuit module (20) away from the output side of the cell body (11). The conductive sheet (30) is connected to the exposed part of the tab (70).

3. The battery cell according to claim 2, characterized in that, The conductive sheet (30) and the tab (70) are connected by a bonding wire (60).

4. The battery cell according to claim 3, characterized in that, The conductive sheet (30) includes a connecting plate (31) and a connecting ear (32) connected at an angle. The connecting plate (31) is fixed on the side of the protection circuit module (20) away from the output side of the battery cell body (11). The connecting ear (32) is aligned and attached to the top seal (12). The connecting ear (32) is connected to the electrode (70) through the bonding wire (60).

5. The battery cell according to claim 4, characterized in that, The tab (70) has two or more windows (120) in the thickness direction of the top seal (12), and all the windows (120) corresponding to each tab (70) are connected to a connecting ear (32).

6. The battery cell according to claim 5, characterized in that, The connecting ear (32) and the pole ear (70) are arranged opposite to each other in the thickness direction of the top seal (12), and each connecting ear (32) is distributed between two adjacent windows (120).

7. The battery cell according to claim 3, characterized in that, The surface of the bonding wire (60) is covered with an anti-corrosion layer, and the bonding wire (60) is fixed to the conductive sheet (30) by adhesive. And / or, The inner diameter of the window (120) is 0.1~1.4mm.

8. The battery cell according to claim 1, characterized in that, From the end of the window (120) near the tab (70) to the end away from the window (120), the inner diameter of the window (120) gradually decreases; And / or, The protection circuit module (20) and the battery cell body (11) are fixed by glue or integrally injection molded.

9. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1-8.

10. An electrical appliance, characterized in that, It includes the battery cell described in any one of claims 1-8 or the battery pack described in claim 9.

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