CN216213727U - Battery cell, battery and power consumption device - Google Patents

Abstract

The embodiment of the application provides a battery monomer, a battery and a power consumption device. The battery cell includes: a housing having an opening; an electrode assembly housed in the case, the electrode assembly including a main body portion and a first tab provided on a side of the main body portion facing the opening; and an end cap for covering the opening, the end cap including a cap body and a first protrusion connected to the cap body, the cap body being provided with a weak portion, the end cap being configured to rupture along the weak portion when an internal pressure of the battery cell reaches a threshold value to discharge the internal pressure. The first protrusion protrudes from the cap body in a direction facing the electrode assembly and supports the first tab such that an avoidance space for avoiding the weak portion is formed between the first tab and the cap body. This application can reduce the risk of first utmost point ear extrusion weak part to improve battery monomer and security performance.

Description

Battery cell, battery and power consumption device

Technical Field

The present application relates to the field of battery technology, and more particularly, to a battery cell, a battery, and an electric device.

Background

The battery cell is widely used in electronic devices such as a mobile phone, a notebook computer, a battery car, an electric airplane, an electric ship, an electric toy car, an electric toy ship, an electric toy airplane, an electric tool, and the like. The battery monomer can comprise a cadmium-nickel battery monomer, a hydrogen-nickel battery monomer, a lithium ion battery monomer, a secondary alkaline zinc-manganese battery monomer and the like.

In addition to improving the performance of the battery cell, safety issues are also a considerable problem in the development of battery technology. If the safety problem of the battery cell cannot be guaranteed, the battery cell cannot be used. Therefore, how to enhance the safety of the battery cell is a technical problem to be solved urgently in the battery technology.

Disclosure of Invention

The application provides a battery monomer, battery and power consumption device, it can improve the free security of battery.

In a first aspect, an embodiment of the present application provides a battery cell, including: a housing having an opening; an electrode assembly housed in the case, the electrode assembly including a main body portion and a first tab provided on a side of the main body portion facing the opening; and an end cap for covering the opening, the end cap including a cap body and a first protrusion connected to the cap body, the cap body being provided with a weak portion, the end cap being configured to rupture along the weak portion when an internal pressure of the battery cell reaches a threshold value to discharge the internal pressure. The first protrusion protrudes from the cap body in a direction facing the electrode assembly and supports the first tab such that an avoidance space for avoiding the weak portion is formed between the first tab and the cap body.

In the above scheme, the first lug can be supported by the first convex part protruding out of the cover body, so that the shaking amplitude of the electrode assembly in the vibration of the battery monomer is reduced, and the stability of the electrode assembly is improved. The first protruding portion supports the first tab to form an avoiding gap for avoiding the weak portion between the first tab and the cover body, so that the risk that the electrode assembly extrudes the weak portion is reduced, the possibility of failure of the weak portion is reduced, and the safety of the battery monomer is improved.

In some embodiments, a first recess recessed from an outer surface of the cap body in a direction facing the electrode assembly is formed at a position corresponding to the first protrusion on the end cap, and a bottom surface of the first recess is closer to the first tab than an inner surface of the cap body.

Above-mentioned scheme guarantees the degree that first convex part protrusion covered the body to support first utmost point ear more effectively, the space is dodged in the increase along thickness direction's size, further reduces the risk of electrode subassembly extrusion weak part. Simultaneously, this application embodiment further guarantees the sunken degree of first concave part under the prerequisite of the degree of protrusion of assurance first convex part to improve the elasticity of first convex part, reduce the risk that first lug was crushed to first convex part in assembling process.

In some embodiments, the first projection is adapted to abut and weld with the first tab to effect electrical connection of the end cap and the first tab.

In the above scheme, the end cap can be directly and electrically connected with the first tab through the first protrusion, so that the structure of the battery cell is simplified.

In some embodiments, the battery cell further includes a current collecting member disposed between the end cap and the first tab. The current collecting component is used for connecting the end cover and the first pole lug so as to realize the electric connection of the end cover and the first pole lug. In the thickness direction of the end cover, an avoiding gap is located between the current collecting member and the cover body.

The first convex part protrudes out of the cover body, so that the cover body and the first lug are separated by the first convex part in the thickness direction; if the end cap and the first tab are directly connected, the first tab can only be connected to the first projection of the end cap, which may cause the area of the first tab capable of directly transmitting current to be limited by the first projection. In the scheme, the current collecting component is arranged to connect the first pole lug and the end cover, so that the area of the first pole lug, which can directly transmit current, is not limited by the first convex part any more, and the current of the first pole lug can be collected into the end cover through the current collecting component, therefore, the current collecting component can reduce the difference of conductive paths between different areas of the first pole lug and the end cover, improve the uniformity of current density of the first pole piece, reduce internal resistance, and improve the overcurrent capacity and charging efficiency of the battery cell. The avoiding gap is positioned between the current collecting component and the cover body, so that the risk that the current collecting component extrudes the weak part can be reduced, the possibility that the current collecting component blocks the exhaust channel can be reduced when the weak part is broken, smooth exhaust is ensured, and the safety is improved.

In some embodiments, the current collecting member covers the weak portion in a thickness direction of the end cover to separate the weak portion from the first tab.

In the above aspect, the current collecting member may separate the weak portion from the first tab to reduce active particles in the electrode assembly falling onto the weak portion, reducing the risk of corrosion of the weak portion.

In some embodiments, the first protrusion surrounds the outside of the cap body, and the current collecting member is used to connect the cap body and the first tab to achieve electrical connection of the end cap and the first tab.

In some embodiments, the current collecting member includes a first current collecting portion for connecting a first tab to electrically connect the current collecting member and the first tab, and a second current collecting portion connected to the first current collecting portion for connecting the cap body to electrically connect the current collecting member and the end cap. The first current collecting portion is convexly arranged on the surface of the second current collecting portion facing the electrode assembly, and an avoiding concave portion which is sunken from the surface of the second current collecting portion, which is far away from the electrode assembly, in the direction facing the electrode assembly is formed on the position of the current collecting member corresponding to the first current collecting portion, so that an avoiding gap is formed between the current collecting member and the cover body.

In the above-mentioned scheme, dodge the concave part through the setting to form dodge the space and avoid first mass flow portion butt on the lid body, thereby reduce the risk of first mass flow portion extrusion weak part, improve the security. The first current collecting portion supports the middle area of the first pole lug, and the first protruding portion supports the edge area of the first pole lug, so that the stress uniformity of the first pole lug can be improved, and the risks of deviation and dislocation of pole pieces of the electrode assembly in the thickness direction are reduced.

In some embodiments, the first current collecting portion is adapted to abut and be welded to the first tab, and the second current collecting portion is adapted to abut and be welded to the cap body.

In the above-mentioned scheme, dodge the recess and can reduce the thickness of first mass flow portion to reduce the welding power that first mass flow portion and first utmost point ear welding need, reduce the heat production, reduce the risk that other components are burnt.

In some embodiments, at least a portion of the current collecting member is located between the first tab and the first tab. The first tab supports the first tab via a current collecting member.

In the above scheme, the first lug is supported by the first convex part through the current collecting component, so that the shaking amplitude of the electrode assembly when the battery monomer shakes is reduced, and the stability of the electrode assembly is improved. Meanwhile, the first convex portion supports the current collecting member to form an avoiding gap between the current collecting member and the cap body.

In some embodiments, a portion of the current collecting member is adapted to abut and be welded to the first tab and another portion of the current collecting member is adapted to abut and be welded to the first tab.

In the scheme, the welding can reduce the contact resistance between the current collecting component and the end cover and the contact resistance between the current collecting component and the first pole lug, and the overcurrent capacity is improved.

In some embodiments, the current collecting member is a flat plate structure.

In the above configuration, the flat plate-shaped current collecting member is more easily molded. The flat-plate-shaped current collecting member can be integrally contacted with the first pole lug, so that the flow area is increased, the current collecting member more uniformly supports the first pole lug, and the risk of deviation and dislocation of the pole piece of the electrode assembly in the thickness direction is reduced. The flat plate-shaped current collecting member can be completely separated from the cap body to ensure an avoiding gap between the current collecting member and the cap body and reduce the risk of the contact of the current collecting member and the weak part.

In some embodiments, the first projection surrounds the outside of the cap body.

In some embodiments, the lid body surrounds an outside of the first projection.

In some embodiments, the end cap further comprises a second protrusion that surrounds the outside of the cap body. The second protrusion protrudes from the inner surface of the cap body in a direction facing the electrode assembly, and a tip surface of the second protrusion is closer to the first tab than a tip surface of the first protrusion, so that the second protrusion abuts against the first tab and serves to support the first tab.

In the scheme, the first convex part supports the middle area of the first tab through the current collecting component, and the second convex part supports the edge area of the first tab, so that the stress uniformity of the first tab can be improved, and the risks of deviation and dislocation of the pole piece of the electrode assembly in the thickness direction are reduced.

In some embodiments, a second recess recessed from the outer surface of the cap body in a direction facing the electrode assembly is formed at a position corresponding to the second protrusion on the end cap, and a bottom surface of the second recess is closer to the first tab than to the inner surface of the cap body.

In the above scheme, under the prerequisite of guaranteeing the degree of protrusion of second convex part, further guarantee the sunken degree of second concave part to improve the elasticity of second convex part, reduce the risk that first utmost point ear was crushed to the second convex part in assembling process.

In some embodiments, the outer side surface of the second protrusion abuts against the inner surface of the housing and is used for welding with the housing to close the opening.

In the above scheme, the welding can realize sealing, reduce the risk that electrolyte reveals to improve joint strength and the current capacity between second convex part and the casing. The second concave part can reduce the strength of the second convex part and improve the elasticity of the second convex part, so that the second convex part can release welding stress through deformation in the process of welding the second convex part and the shell, the risks of deformation and cracking of a welding area are reduced, and the sealing performance is improved.

In some embodiments, the lid body is a flat plate structure.

In some embodiments, the cover body includes a main plate body surrounding an outer side of the third convex portion, and a first convex portion surrounding the outer side of the main plate body, and the weak portion is formed at the third convex portion. The main plate body includes a first inner surface and a first outer surface that are disposed opposite to each other, the first inner surface facing the electrode assembly, the first projection and the third projection each projecting from the first inner surface in a direction facing the electrode assembly, and a tip end surface of the first projection is closer to the first tab than a tip end surface of the third projection to form an avoidance space for avoiding the weak portion between the current collecting member and the third projection.

In the scheme, the third convex part is arranged in the middle of the end cover, so that the strength of the end cover can be increased, and the deformation of the end cover is reduced. The third convex part is the convex state, and non-deformable consequently, sets up the weak part on the third convex part, can reduce the creep of weak part to reduce the risk that the weak part became invalid. According to the scheme, the avoiding gap is formed between the third convex part and the current collecting component, so that the risk that the current collecting component blocks the exhaust channel when the weak part is broken is reduced, smooth exhaust is guaranteed, and the safety risk is reduced.

In some embodiments, a third concave portion depressed from the first outer surface in a direction facing the electrode assembly is formed on the cap body at a position corresponding to the third convex portion, and the third convex portion forms a weak portion at a region opposite to a bottom surface of the third concave portion.

In the above aspect, the weak portion is formed in the region of the third protruding portion that opposes the bottom surface of the third recessed portion, so that the distance between the weak portion and another external member can be increased, and the risk of the weak portion being crushed by the external member is reduced.

In some embodiments, the cap body is provided with a recess, and the region of the cap body opposite the recess forms the weakened portion.

In the above scheme, the thickness and strength of the weak portion are reduced by providing the groove, so that the end cap can be ruptured along the weak portion when the internal pressure of the battery cell reaches a threshold value.

In some embodiments, the end cap electrically connects the first tab and the housing.

In the above scheme, the housing itself can be used as the output electrode of the battery cell. When a plurality of battery monomers are assembled into a group, the shell can be electrically connected with the confluence component, so that the flow area can be increased, and the structural design of the confluence component can be more flexible.

In some embodiments, the case includes a side wall extending in a thickness direction of the end cap and disposed around an outer circumference of the electrode assembly, and a bottom wall connected to the side wall, the bottom wall being provided with an electrode lead-out hole. The electrode assembly further comprises a second tab, and the first tab and the second tab have opposite polarities and are respectively located at two ends of the electrode assembly. The battery unit also comprises an electrode terminal arranged in the electrode leading-out hole, and the electrode terminal is electrically connected with the second lug.

In the above scheme, the bottom wall and the electrode terminal can be used as two output electrodes of the battery cell, so that the structure of the battery cell can be simplified, and the overcurrent capacity of the battery cell can be ensured. The bottom wall and the electrode terminal are located at the same end of the battery cell, so that when a plurality of battery cells are assembled into a group, the bus member can be assembled to the same side of the battery cell, thus simplifying the assembly process and improving the assembly efficiency.

In some embodiments, the bottom wall and the side wall are integrally provided. This scheme can save the connection process of diapire and lateral wall.

In some embodiments, the first tab is a negative tab, and the base material of the casing is steel.

In the above scheme, the casing is electrically connected with the negative electrode tab, that is, the casing is in a low potential state. The steel shell is not easily corroded by electrolyte in a low potential state, so that safety risk is reduced.

In some embodiments, the base material of the housing and the base material of the end cap are the same. The scheme can ensure the welding strength of the shell and the end cover and ensure the sealing performance of the battery monomer.

In some embodiments, the battery cell is a cylindrical battery cell.

In a second aspect, an embodiment of the present application provides a battery, including a plurality of battery cells according to any of the embodiments of the first aspect.

In a third aspect, an embodiment of the present application provides an electric device, including the battery of the second aspect, where the battery is used to provide electric energy.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for a person skilled in the art to obtain other drawings based on the drawings without any creative effort.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

fig. 2 is an exploded schematic view of a battery provided in accordance with some embodiments of the present application;

fig. 3 is an exploded schematic view of the battery module shown in fig. 2;

fig. 4 is an exploded schematic view of a battery cell provided in some embodiments of the present application;

fig. 5 is a schematic cross-sectional view of a battery cell provided in some embodiments of the present application;

fig. 6 is an enlarged schematic view of the battery cell shown in fig. 5 at a circle frame a;

fig. 7 is a schematic cross-sectional view of a battery cell provided in accordance with other embodiments of the present application;

fig. 8 is an enlarged schematic view of the battery cell shown in fig. 7 at a circle frame B;

fig. 9 is a schematic cross-sectional view of a battery cell provided in accordance with further embodiments of the present application;

fig. 10 is an enlarged schematic view of the battery cell shown in fig. 9 at block C;

fig. 11 is a schematic flow chart of a method for manufacturing a battery cell according to some embodiments of the present disclosure;

fig. 12 is a schematic block diagram of a system for manufacturing a battery cell provided in some embodiments of the present application.

In the drawings, the drawings are not necessarily to scale.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the above-described drawings are used for distinguishing between different elements and not for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "attached" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The term "and/or" in this application is only one kind of association relationship describing the associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this application generally indicates that the preceding and following associated objects are in an "or" relationship.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In this application, the battery cell may include a lithium ion secondary 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, and the embodiment of the present application is not limited thereto. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery cell comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive pole piece, a negative pole piece and a separator. The battery cell mainly depends on metal ions to move between the positive pole piece and the negative pole piece to work. The positive pole piece comprises a positive current collector and a positive active substance layer, and the positive active substance layer is coated on the surface of the positive current collector; the positive pole mass flow body includes anodal coating district and connects in anodal utmost point ear in the coating district of positive pole, and anodal coating district coats the anodal active substance layer, and anodal utmost point ear does not coat anodal active substance layer. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece comprises a negative pole current collector and a negative pole active substance layer, and the negative pole active substance layer is coated on the surface of the negative pole current collector; the negative current collector comprises a negative coating area and a negative electrode lug connected to the negative coating area, the negative coating area is coated with a negative active material layer, and the negative electrode lug is not coated with the negative active material layer. The material of the negative electrode current collector may be copper, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may be carbon, silicon, or the like. The material of the spacer may be PP (polypropylene) or PE (polyethylene).

The battery cell further includes a case having an opening and receiving the electrode assembly, and an end cap, through which the electrode assembly may be fitted into the case. The end cover is used for covering the opening of the shell to realize sealing.

For cells, the main safety hazard comes from the charging and discharging processes, and at the same time, with a suitable ambient temperature design, there are generally at least three protective measures for the cells in order to effectively avoid unnecessary losses. In particular, the protective measures comprise at least a switching element, the selection of a suitable spacer material and a pressure relief mechanism. The switching element is an element that can stop charging or discharging the battery when the temperature or resistance in the battery cell reaches a certain threshold value. The separator is used for separating the positive pole piece and the negative pole piece, and can automatically dissolve the micron-scale (even nano-scale) micropores attached to the separator when the temperature rises to a certain value, so that metal ions cannot pass through the separator, and the internal reaction of the battery monomer is stopped.

The pressure relief mechanism refers to an element or a component that is actuated to relieve the internal pressure of the battery cell when the internal pressure reaches a predetermined threshold. The threshold design varies according to design requirements. The threshold may depend on the material of one or more of the positive electrode tab, the negative electrode tab, the electrolyte and the separator in the battery cell.

As used herein, "activate" means that the pressure relief mechanism is activated or activated to a state such that the internal pressure of the battery cell is vented. The actions generated by the pressure relief mechanism may include, but are not limited to: at least a portion of the pressure relief mechanism ruptures, fractures, is torn or opened, or the like. When the pressure relief mechanism is actuated, high-temperature and high-pressure substances in the battery cells are discharged outwards from the actuated part as emissions. In this way, the cells can be vented under controlled pressure, thereby avoiding potentially more serious accidents. Reference herein to emissions from the battery cell includes, but is not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gas generated by reaction, flame and the like.

The pressure relief mechanism on the single battery has an important influence on the safety of the single battery. For example, when a short circuit or overcharge occurs, thermal runaway may occur in the battery cell, and the pressure may suddenly rise. In this case, the internal pressure can be released outwards by the actuation of the pressure relief mechanism, so as to prevent the battery cell from exploding and igniting.

The pressure relief mechanism may take the form of, for example, an explosion-proof valve, a gas valve, a pressure relief valve, a safety valve, or the like, and may specifically take the form of a pressure-sensitive element or configuration, i.e., when the internal pressure of the battery cell reaches a predetermined threshold, the pressure relief mechanism performs an action or a weak structure provided in the pressure relief mechanism is broken, thereby forming an opening or a channel through which the internal pressure can be released.

To simplify the cell structure, the inventors attempted to integrate the pressure relief mechanism into the end cap. For example, the inventors provide a weakness in the end cap, and the end cap is configured to rupture along the weakness when the internal pressure of the cell reaches a threshold value to vent the internal pressure. When short circuit, overcharge and other phenomena occur, thermal runaway may occur inside the battery cell, and thus the pressure rises suddenly, in which case the internal pressure may be released outwards by the rupture of the weak portion, so as to prevent the battery cell from exploding and firing, thereby improving safety.

However, the inventors have studied and found that, when the battery cell vibrates, the tabs of the electrode assembly are easily pressed and hit the weak portions; due to the fact that the strength of the weak portion is low, when the weak portion is extruded and impacted by the pole lug, the weak portion can be broken when the internal pressure of the single battery does not reach a threshold value, the single battery fails, and safety problems are caused.

In view of this, embodiments of the present application provide a technical solution in which an end cap includes a cap body and a first protrusion connected to the cap body, the cap body is provided with a weak portion, and the first protrusion protrudes from the cap body in a direction facing an electrode assembly and is used to support a tab of the electrode assembly, so that an avoidance gap for avoiding the weak portion is formed between the tab and the cap body. The battery cell with the structure can reduce the risk of the electrode assembly extruding the weak part and improve the safety of the battery cell.

The technical scheme described in the embodiment of the application is suitable for the battery and the electric device using the battery.

The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like; spacecraft include aircraft, rockets, space shuttles, and spacecraft, among others; electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and electric power tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not specifically limit the above power utilization device.

For convenience of explanation, the following embodiments will be described by taking an electric device as an example of a vehicle.

Fig. 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application. As shown in fig. 1, a battery 2 is provided inside a vehicle 1, and the battery 2 may be provided at the bottom or the head or the tail of the vehicle 1. The battery 2 may be used for power supply of the vehicle 1, and for example, the battery 2 may serve as an operation power source of the vehicle 1.

The vehicle 1 may further comprise a controller 3 and a motor 4, the controller 3 being adapted to control the battery 2 to power the motor 4, e.g. for start-up, navigation and operational power demands while driving of the vehicle 1.

In some embodiments of the present application, the battery 2 may not only serve as an operating power source of the vehicle 1, but also serve as a driving power source of the vehicle 1, instead of or in part of fuel or natural gas, to provide driving power for the vehicle 1.

Fig. 2 is an exploded view of a battery provided in some embodiments of the present application. As shown in fig. 2, the battery 2 includes a case 5 and a battery cell (not shown in fig. 2) accommodated in the case 5.

The case 5 is used for accommodating the battery cells, and the case 5 may have various structures. In some embodiments, the case 5 may include a first case portion 5a and a second case portion 5b, the first case portion 5a and the second case portion 5b cover each other, and the first case portion 5a and the second case portion 5b together define a receiving space 5c for receiving the battery cell. The second casing part 5b may be a hollow structure with one open end, the first casing part 5a is a plate-shaped structure, and the first casing part 5a covers the open side of the second casing part 5b to form a casing 5 with a containing space 5 c; the first casing portion 5a and the second casing portion 5b may be hollow structures each having one side opened, and the opening side of the first casing portion 5a may be covered with the opening side of the second casing portion 5b to form the casing 5 having the accommodating space 5c. Of course, the first casing portion 5a and the second casing portion 5b may be various shapes, such as a cylinder, a rectangular parallelepiped, or the like.

In order to improve the sealing property after the first casing portion 5a and the second casing portion 5b are connected, a sealing member, such as a sealant or a gasket, may be provided between the first casing portion 5a and the second casing portion 5 b.

Assuming that the first box portion 5a covers the top of the second box portion 5b, the first box portion 5a may also be referred to as an upper box cover, and the second box portion 5b may also be referred to as a lower box cover.

In the battery 2, one or more battery cells may be provided. If the number of the battery monomers is multiple, the multiple battery monomers can be connected in series or in parallel or in series-parallel, and the series-parallel refers to that the multiple battery monomers are connected in series or in parallel. The plurality of battery monomers can be directly connected in series or in parallel or in series-parallel, and the whole formed by the plurality of battery monomers is accommodated in the box body 5; of course, a plurality of battery cells may be connected in series or in parallel or in series-parallel to form the battery module 6, and a plurality of battery modules 6 may be connected in series or in parallel or in series-parallel to form a whole and accommodated in the box 5.

Fig. 3 is an exploded view of the battery module shown in fig. 2.

In some embodiments, as shown in fig. 3, there are a plurality of battery cells 7, and the plurality of battery cells 7 are connected in series or in parallel or in series-parallel to form the battery module 6. A plurality of battery modules 6 are connected in series or in parallel or in series-parallel to form a whole and are accommodated in the case.

The plurality of battery cells 7 in the battery module 6 may be electrically connected to each other by a bus member, so as to realize parallel connection, series connection, or parallel-series connection of the plurality of battery cells 7 in the battery module 6.

Fig. 4 is an exploded schematic view of a battery cell provided in some embodiments of the present application; fig. 5 is a schematic cross-sectional view of a battery cell provided in some embodiments of the present application; fig. 6 is an enlarged schematic view of the battery cell shown in fig. 5 at a circle frame a.

As shown in fig. 4 to 6, the battery cell 7 of the embodiment of the present application includes: a housing 20 having an opening 21; an electrode assembly 10 accommodated in the case 20, the electrode assembly 10 being provided with a first tab 12 at one end facing the opening 21; and an end cap 30 for covering the opening 21, the end cap 30 including a cap body 31 and a first protrusion 32 connected to the cap body 31, the cap body 31 being provided with a weak portion 311, the end cap 30 being configured to rupture along the weak portion 311 when the internal pressure of the battery cell 7 reaches a threshold value to discharge the internal pressure. The first protrusion 32 protrudes from the cap body 31 in a direction facing the electrode assembly 10 and serves to support the first tab 12 such that an escape gap G for escaping the weak portion 311 is formed between the first tab 12 and the cap body 31.

The electrode assembly 10 includes a first pole piece, a second pole piece, and a separator for separating the first pole piece and the second pole piece. The first and second pole pieces have opposite polarities, that is, one of the first and second pole pieces is a positive pole piece, and the other of the first and second pole pieces is a negative pole piece.

Optionally, the first pole piece, the second pole piece and the spacer are all in a belt-shaped structure, and the first pole piece, the second pole piece and the spacer are wound into a whole and form a winding structure. The coiled structure may be a cylindrical structure, a flat structure, or other shaped structure.

The electrode assembly 10 includes a main body portion 11, a first tab 12, and a second tab 13, the first tab 12 and the second tab 13 protruding from the main body portion 11, as viewed from the external shape of the electrode assembly 10. The first tab 12 is a portion of the first pole piece not coated with the active material layer, and the second tab 13 is a portion of the second pole piece not coated with the active material layer. Correspondingly, one of the first tab 12 and the second tab 13 is a tab with positive polarity, and the other is a tab with negative polarity.

The first tab 12 and the second tab 13 may extend from the same side of the body 11, or may extend from opposite sides.

Illustratively, the first and second tabs 12 and 13 are respectively provided at both sides of the body part 11, in other words, the first and second tabs 12 and 13 are respectively provided at both ends of the electrode assembly 10. Alternatively, the first tab 12 is located at one end of the electrode assembly 10 facing the end cap 30, and the second tab 13 is located at one end of the electrode assembly 10 facing away from the end cap 30.

Optionally, the first tab 12 is wound around the central axis X of the electrode assembly 10 in multiple turns, in other words, the first tab 12 includes multiple tab layers. After winding, the first tab 12 is substantially cylindrical, and a gap is left between two adjacent tab layers. The embodiment of the application can process the first tab 12 to reduce the gap between tab layers, so that the first tab 12 is connected with other conductive structures conveniently. For example, the present embodiment may perform a flattening treatment on the first tab 12 to gather and bring together the end regions of the first tab 12 away from the main body portion 11; the flattening process forms a compact end surface at one end of the first tab 12 far away from the main body part 11, so that the gap between tab layers is reduced, and the first tab 12 is convenient to be connected with other conductive structures. Alternatively, the embodiment of the application can also fill a conductive material between two adjacent circles of tab layers to reduce the gap between the tab layers.

Alternatively, the second tab 13 is wound around the central axis X of the electrode assembly 10 in a plurality of turns, and the second tab 13 includes a plurality of turns of tab layers. Illustratively, the second pole ear 13 is also given a flattening treatment to reduce the gap between the pole ear layers of the second pole ear 13.

The case 20 has a hollow structure with one side open, and the end cap 30 covers the opening 21 of the case 20 and is hermetically connected to form a receiving cavity for receiving the electrode assembly 10 and the electrolyte.

The case 20 has a hollow structure, and a space for receiving the electrode assembly 10 is formed inside thereof. The housing 20 may be in various shapes, such as a cylinder, a rectangular parallelepiped, and the like. The shape of the case 20 may be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is of a cylindrical structure, it may be optionally a cylindrical case; if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped case may be used.

The case 20 includes a side wall 22 surrounding the outside of the electrode assembly 10, and a bottom wall 23 connected to one end of the side wall 22. The side wall 22 is a cylindrical structure, for example, the side wall 22 may be a cylinder or a square cylinder; the bottom wall 23 is a plate-like structure having a shape corresponding to the shape of the side wall 22. Alternatively, one end of the side wall 22 forms the opening 21 and the bottom wall 23 is connected to the end of the side wall 22 facing away from the opening 21.

The side wall 22 and the bottom wall 23 may be integrally formed structures, i.e., the housing 20 is an integrally formed member. Of course, the side wall 22 and the bottom wall 23 may also be two members provided separately and then joined together by welding, riveting, bonding, or the like.

The end cap 30 may be electrically connected to the electrode assembly 10, or may be disposed to be insulated from the electrode assembly 10. Optionally, an end cap 30 is electrically connected to the first tab 12. Of course, the end cap 30 may be electrically connected to the first tab 12 directly, or may be electrically connected to the first tab 12 through another conductive member.

The housing 20 may be positively charged, negatively charged, or uncharged. When the case 20 needs to be charged, the case 20 may be directly connected to the tabs of the electrode assembly 10, or may be electrically connected to the tabs through other conductive members.

The end cap 30 and the housing 20 may be connected by welding so that the end cap 30 and the housing 20 may have the same polarity. Illustratively, when positive charging of the housing 20 is desired, the end cap 30 may be utilized to electrically connect the housing 20 to a positive polarity tab; when the housing 20 needs to be negatively charged, the end cap 30 may be used to electrically connect the housing 20 to a tab of negative polarity. Of course, the housing 20 may be connected to the tab through other conductive structures, and the embodiment is not limited thereto.

The housing 20 and the end cap 30 may be made of the same material or may be made of different materials.

The cap body 31 is a plate-shaped structure having inner and outer surfaces oppositely disposed in the thickness direction Z of the end cap 30, and the inner surface 31a of the cap body faces the electrode assembly 10. The inner surface 31a of the cap body may be flat, curved, or a combination of flat and curved. The outer surface 31b of the cap body may be flat, curved, or a combination of flat and curved. Alternatively, the inner surface 31a of the cap body and the outer surface 31b of the cap body are both planar and arranged in parallel.

The weak portion 311 is a part of the cap body 31, and the strength of the weak portion 311 is smaller than other parts of the cap body 31. The present embodiment may reduce the strength of the weak portion 311 by reducing the thickness of the weak portion 311, changing the material of the weak portion 311, or other means.

The weakened portion 311 may be formed around the central axis X of the electrode assembly 10 by one turn, or may be formed around only the central axis X by 1/2 turn, 2/3 turn, or 3/4 turn, and the present embodiment is not limited thereto.

The first protrusion 32 protrudes in a direction facing the electrode assembly 10 with respect to the inner surface 31a of the cap body such that at least a portion of the first protrusion 32 protrudes from the inner surface 31a of the cap body. The present embodiment does not limit the extent to which the first projection 32 projects from the inner surface 31a of the cap body.

One or more first protrusions 32 may be provided. Alternatively, when the first protrusion 32 is plural, the plural first protrusions 32 may be provided at intervals along the circumferential direction of the end cap 30.

The first protrusion 32 may abut against the first tab 12 to directly support the first tab 12; of course, the first projection 32 may indirectly support the first tab 12 by supporting other members.

In the thickness direction Z, an escape gap G is located between the first tab 12 and the cover body 31. The relief gap G is a space formed between the first tab 12 and the cover body 31 and not filled with other solid members. The escape gap G faces the weak portion 311 in the thickness direction Z, and functions to escape the weak portion 311.

Other members may be provided between the first tab 12 and the cover body 31 as long as the escape gap G can escape the member from the weak portion 311. Of course, no other member may be provided between the first tab 12 and the cover body 31.

In the present embodiment, the first protrusion 32 protruding from the cover body 31 may support the first tab 12, so as to reduce the shaking amplitude of the electrode assembly 10 when the battery cell 7 shakes, and improve the stability of the electrode assembly 10. The first protrusion 32 supports the first tab 12 to form an avoidance gap G for avoiding the weak portion 311 between the first tab 12 and the cover body 31, thereby reducing the risk of the electrode assembly 10 pressing the weak portion 311, reducing the possibility of failure of the weak portion 311, and improving the safety of the battery cell 7.

In particular, with the first tab 12 having a wound structure, the end surface thereof facing away from the main body portion 11 is less flat, and if the end surface of the first tab 12 presses the weak portion 311, the weak portion 311 is more easily broken. This application avoids clearance G through setting up to reduce the risk of first utmost point ear 12 extrusion weak part 311, reduce the possibility that weak part 311 became invalid.

In some embodiments, the cover body 31 is provided with a groove 312, and a region of the cover body 31 opposite to the groove 312 forms the weak portion 311.

Alternatively, the groove 312 may be provided to the inner surface 31a of the cap body, and the weak portion 311 is a portion of the cap body 31 between the bottom surface of the groove 312 and the outer surface 31b of the cap body. Alternatively, the groove 312 may be provided to the outer surface 31b of the cap body, and the weak portion 311 is a portion of the cap body 31 between the bottom surface of the groove 312 and the inner surface 31a of the cap body.

The present embodiment reduces the thickness and strength of the weak portion 311 by providing the groove 312, thereby enabling the end cap 30 to be ruptured along the weak portion 311 when the internal pressure of the battery cell 7 reaches a threshold value.

In some embodiments, the groove 312 may be provided to the inner surface 31a of the cap body. The groove 312 communicates with the escape gap G.

The groove 312 of the present embodiment may further increase the distance between the weak portion 311 and the first tab 12, reducing the risk of the first tab 12 pressing the weak portion 311.

In some embodiments, the first tab 12 is electrically connected to the end cap 30.

The end cap 30 may be directly connected to the first tab 12, for example, the end cap 30 may be directly welded to the first tab 12 to electrically connect the end cap 30 and the first tab 12.

Alternatively, the end cap 30 may be indirectly connected to the first tab 12 via another electrically conductive structure (e.g., a current collecting member, described below). The present embodiment may connect the first protrusion 32 to the conductive structure, or may connect the cover body 31 to the conductive structure.

In this embodiment, the end cap 30 may be charged and may serve as an output electrode of the battery cell 7, thereby omitting a conventional electrode terminal and simplifying the structure of the battery cell 7.

In some embodiments, the end cap 30 electrically connects the first tab 12 and the housing 20.

In the present embodiment, the case 20 itself may serve as an output pole of the battery cell 7. When a plurality of battery cells 7 are assembled into a group, the housing 20 may be electrically connected to the bus bar member, which may increase the flow area and may also make the structural design of the bus bar member more flexible.

In some embodiments, the case 20 includes a side wall 22 and a bottom wall 23 connected to the side wall 22, the side wall 22 extends in the thickness direction Z of the end cap 30 and is disposed around the outer circumference of the electrode assembly 10, and the bottom wall 23 is provided with an electrode lead-out hole 231. The electrode assembly 10 further includes a second tab 13, and the first tab 12 and the second tab 13 have opposite polarities and are located at both ends of the electrode assembly 10, respectively. The battery cell 7 further includes an electrode terminal 40 mounted to the electrode lead-out hole 231, the electrode terminal 40 being electrically connected to the second tab 13.

The second tab 13 may be electrically connected to the electrode terminal 40 directly or may be electrically connected to the electrode terminal 40 indirectly through another conductive structure.

The electrode terminal 40 is insulated from the bottom wall 23, the electrode terminal 40 and the bottom wall 23 may have different polarities, and the electrode terminal 40 and the bottom wall 23 may respectively serve as two output poles of the battery cell 7.

When the first tab 12 is a negative tab and the second tab 13 is a positive tab, the bottom wall 23 is a negative output electrode of the battery cell 7, and the electrode terminal 40 is a positive output electrode of the battery cell 7. When the first tab 12 is a positive tab and the second tab 13 is a negative tab, the bottom wall 23 is a positive output electrode of the battery cell 7, and the electrode terminal 40 is a negative output electrode of the battery cell 7.

The electrode terminal 40 is fixed to the bottom wall 23. The electrode terminal 40 may be integrally fixed to the outside of the bottom wall 23, or may be extended into the case 20 through the electrode lead-out hole 231.

The first tab 12 is located at one end of the electrode assembly 10 facing the end cap 30 so that the end cap 30 is electrically connected to the first tab 12; correspondingly, a second tab 13 is located at one end of the electrode assembly 10 facing the bottom wall 23 so that the electrode terminal 40 is electrically connected to the second tab 13. The first tab 12 and the second tab 13 are disposed at two ends of the electrode assembly 10, so that the risk of conduction of the first tab 12 and the second tab 13 can be reduced, and the flow area of the first tab 12 and the flow area of the second tab 13 can be increased.

In the present embodiment, the bottom wall 23 and the electrode terminals 40 may serve as two output electrodes of the battery cell 7, which may simplify the structure of the battery cell 7 and secure the overcurrent capability of the battery cell 7. The bottom wall 23 and the electrode terminals 40 are located at the same end of the battery cell 7, so that the bus member can be assembled to the same side of the battery cell 7 when a plurality of battery cells 7 are assembled into a group, which can simplify the assembly process and improve the assembly efficiency.

In some embodiments, the bottom wall 23 and the side wall 22 are integrally provided. This embodiment can omit the process of connecting the bottom wall 23 and the side wall 22. The housing 20 may be formed by a drawing process.

The electrode lead-out hole 231 of the embodiment of the present application is formed after the housing 20 is stretch-molded.

The inventors have attempted to roll the open end of the shell so that the open end of the shell is folded inwardly and forms a flange structure which presses against the end cap to effect securement of the end cap. The inventors mounted the electrode terminals to the end cap and used the burring structure and the electrode terminals as two output poles of the battery cell. However, the larger the size of the cuff structure, the higher the risk of curling and creasing after forming; if the burring structure is curled and wrinkled, unevenness of the surface of the burring structure may be caused, and there may be a problem of poor welding when the burring structure is welded with the bus bar member. Therefore, the size of the flanging structure is limited, and the overcurrent capacity of the battery cell is insufficient.

The present embodiment forms an electrode lead-out hole 231 for mounting the electrode terminal 40 on the bottom wall 23 using a punching process to dispose the positive and negative output electrodes at one end of the battery cell 7 facing away from the opening 21; the bottom wall 23 is formed in the molding process of the housing 20, and the flatness of the bottom wall 23 can be ensured even after the electrode lead-out hole 231 is formed, so that the connection strength between the bottom wall 23 and the bus member can be ensured. Meanwhile, the flatness of the bottom wall 23 is not restricted by its size, so that the bottom wall 23 can have a larger size, thereby improving the overcurrent capacity of the battery cell 7.

In some embodiments, the first tab 12 is a negative tab, and the base material of the casing 20 is steel.

The case 20 is electrically connected to the negative electrode tab, i.e., the case 20 is in a low potential state. The steel case 20 is not easily corroded by the electrolyte in a low potential state to reduce safety risk.

In some embodiments, the housing 20 is welded to the end cap 30. The welding can realize the connection of the shell 20 and the end cover 30, improve the flow capacity between the shell 20 and the end cover 30 and ensure the sealing property.

In some embodiments, the base material of the housing 20 is the same as the base material of the end cap 30. Optionally, the base material of the housing 20 and the base material of the end cap 30 are both steel.

In this embodiment, the base material of the case 20 is the same as the base material of the end cap 30, so that the welding strength between the case 20 and the end cap 30 can be ensured, and the sealing performance of the single battery 7 can be ensured.

In some embodiments, the battery cell 7 is a cylindrical battery cell. Correspondingly, the electrode assembly 10 has a cylindrical structure, and the case 20 has a cylindrical hollow structure.

In some embodiments, the end cap 30 is formed with a first recess 33 recessed from the outer surface 31b of the cap body in a direction facing the electrode assembly 10 at a position corresponding to the first protrusion 32, and a bottom surface of the first recess 33 is closer to the first tab 12 than to the inner surface 31a of the cap body.

The first concave part 33 can reduce the strength of the first convex part 32 and improve the elasticity of the first convex part 32, so that in the process that the first convex part 32 extends into the shell 20 and abuts against the first tab 12, the first convex part 32 can release stress through deformation, the impact force is reduced, and the risk that the first tab 12 is crushed is reduced.

The first recess 33 and the first protrusion 32 may be formed by stamping the end cap 30. The greater the depth of the first concave portion 33 in the thickness direction Z, the greater the extent to which the first convex portion 32 projects from the inner surface 31a of the lid body, and the greater the relief gap G.

The embodiment of the present application can ensure the degree of the first protrusion 32 protruding out of the cover body 31 to more effectively support the first tab 12, increase the size of the avoiding gap G along the thickness direction Z, and further reduce the risk of the electrode assembly 10 pressing the weak portion 311. Meanwhile, on the premise of ensuring the protruding degree of the first convex part 32, the embodiment further ensures the sunken degree of the first concave part 33 so as to improve the elasticity of the first convex part 32 and reduce the risk that the first convex part 32 crushes the first tab 12 in the assembling process.

Alternatively, the bottom surface of the first recess 33 is planar and parallel to the inner surface 31a of the cover body.

In some embodiments, the battery cell 7 further includes a current collecting member 50 disposed between the end cap 30 and the first tab 12. The current collecting member 50 is used to connect the end cover 30 and the first tab 12 to electrically connect the end cover 30 and the first tab 12. In the thickness direction Z of the end cover 30, an avoiding gap G is located between the current collecting member 50 and the cover body 31.

The current collecting member 50 may be welded, bonded or otherwise attached to the first tab 12 to achieve electrical connection with the first tab 12. The current collecting member 50 may be welded, bonded, or otherwise connected to the end cap 30 to achieve electrical connection with the end cap 30.

The current collecting member 50 may be connected to the first protrusion 32, may be connected to the cap body 31, and may be connected to other portions of the end cap 30.

The first protrusion 32 protrudes from the cover body 31, so that the first protrusion 32 separates the cover body 31 and the first tab 12 in the thickness direction Z; if the end cap 30 and the first tab 12 are directly connected, the first tab 12 can be connected only to the first projection 32 of the end cap 30. If the first protrusion 32 and the first tab 12 are directly connected, only a portion of the first tab 12 opposite to the first protrusion 32 can be directly connected to the first protrusion 32, resulting in that an area of the first tab 12 capable of directly transmitting current is limited by the first protrusion 32, resulting in an insufficient flow area between the first protrusion 32 and the first tab 12; the current on the portion of the first tab 12 opposite to the cover body 31 in the thickness direction Z needs to flow to the portion of the first tab 12 welded to the first protrusion 32 and then to flow to the first protrusion 32, which may cause large difference in the conductive paths between different regions of the first tab 12 and the end cover 30, and affect the overcurrent capacity and charging efficiency of the battery cell 7.

According to the embodiment of the application, the current collecting member 50 is arranged to connect the first tab 12 and the end cover 30, so that the area of the first tab 12, which can directly transmit current, is not limited by the first protrusion 32 any more, and the current of the first tab 12 can be collected into the end cover 30 through the current collecting member 50, so that the current collecting member 50 can reduce the difference of conductive paths between different areas of the first tab 12 and the end cover 30, improve the uniformity of current density of the first pole piece, reduce internal resistance, and improve the overcurrent capacity and charging efficiency of the battery cell 7.

In the present embodiment, the avoiding gap G is located between the current collecting member 50 and the cap body 31, so that the risk of the current collecting member 50 pressing the weak portion 311 can be reduced, and the possibility of the current collecting member 50 blocking the exhaust passage when the weak portion 311 is broken can be reduced, thereby ensuring smooth exhaust and improving safety.

In some embodiments, the current collecting member 50 covers the weak portion 311 in the thickness direction Z of the end cover 30 to separate the weak portion 311 from the first tab 12.

A part of the current collecting member 50 is disposed at an interval from the weak portion 311 in the thickness direction Z and covers the weak portion 311. The projection of the weak portion 311 in the thickness direction Z is located within the projection of the current collecting member 50 in the thickness direction Z.

In the present embodiment, the current collecting member 50 may space the weak portion 311 from the first tab 12 to reduce active particles in the electrode assembly 10 falling onto the weak portion 311, reducing the risk of corrosion of the weak portion 311.

In some embodiments, at least a portion of the current collecting member 50 is located between the first tab 32 and the first tab 12. The first tab 32 supports the first tab 12 via the current collecting member 50.

The first protrusions 32 support the first tabs 12 via the current collecting member 50 to reduce the shaking amplitude of the electrode assembly 10 when the battery cells 7 vibrate, and improve the stability of the electrode assembly 10. Meanwhile, the first protrusion 32 supports the current collecting member 50 to form an avoiding gap G between the current collecting member 50 and the cap body 31.

In some embodiments, a portion of the current collecting member 50 is adapted to abut and weld with the first tab 12 and another portion of the current collecting member 50 is adapted to abut and weld with the first projection 32.

When assembling the single battery 7, the current collecting member 50 is pressed against and welded to the first tab 12 to form a first welding portion W1, and then the end cap 30 and the current collecting member 50 are welded to form a second welding portion W2.

The present embodiment welds two different portions of the current collecting member 50 to the end cover 30 and the first tab 12, respectively, to reduce the risk of welding the first weld W1 with the second weld W2, and ensure the connection strength of the current collecting member 50 and the first tab 12 and the connection strength of the end cover 30 and the current collecting member 50.

Welding may reduce the contact resistance between the current collecting member 50 and the end cap 30 and between the current collecting member 50 and the first tab 12, increasing the current carrying capacity.

In some embodiments, current collecting member 50 is a flat plate structure.

The flat plate-shaped current collecting member 50 is more easily molded. The plate-shaped current collecting member 50 may be entirely in contact with the first tab 12, thereby increasing an area of flow, and allowing the current collecting member 50 to more uniformly support the first tab 12, reducing a risk of displacement or misalignment of the pole pieces of the electrode assembly 10 in the thickness direction Z. The flat plate-shaped current collecting member 50 can also be completely spaced from the lid body 31 to ensure an avoiding gap G between the current collecting member 50 and the lid body 31, reducing the risk of the current collecting member 50 coming into contact with the weak portion 311.

In some embodiments, the cover body 31 surrounds the outside of the first protrusion 32. In other words, the cap body 31 is an annular structure that surrounds the outside of the first protrusion 32.

In some embodiments, the end cap 30 further includes a second protrusion 34, the second protrusion 34 surrounding the outside of the cap body 31. The second protrusion 34 protrudes from the inner surface 31a of the cap body in a direction facing the electrode assembly 10, and a tip end surface of the second protrusion 34 is closer to the first tab 12 than a tip end surface of the first protrusion 32, so that the second protrusion 34 abuts against the first tab 12 and serves to support the first tab 12.

The second projection 34 is an annular structure that surrounds the outside of the cap body 31. The tip end surface of the first projection 32 abuts against the current collecting member 50; alternatively, the tip end surface of the first projection 32 is a flat surface. The tip end surface of the second projection 34 abuts against the first tab 12; alternatively, the tip end surface of the second projection 34 is a flat surface or a curved surface.

The second protrusion 34 is spaced apart from the current collecting member 50 to prevent the second protrusion 34 from interfering with the contact between the current collecting member 50 and the first protrusion 32, thereby ensuring that the first protrusion 32 is tightly attached to the current collecting member 50. Optionally, the second tab 34 surrounds the outside of the current collecting member 50.

The second projection 34 projects from the inner surface 31a of the cap body to a greater extent than the first projection 32 projects from the inner surface 31a of the cap body, so that the tip end surface of the second projection 34 is closer to the first tab 12 than the tip end surface of the first projection 32.

In the present embodiment, the first protrusion 32 supports the middle region of the first tab 12 through the current collecting member 50, and the second protrusion 34 supports the edge region of the first tab 12, so that the stress uniformity of the first tab 12 may be improved, and the risk of the pole pieces of the electrode assembly 10 being shifted or dislocated in the thickness direction Z may be reduced.

In some embodiments, a second recess 35 recessed from the outer surface 31b of the cap body in a direction facing the electrode assembly 10 is formed at a position corresponding to the second protrusion 34 on the end cap 30, and a bottom surface of the second recess 35 is closer to the first tab 12 than to the inner surface 31a of the cap body.

The second concave part 35 can reduce the strength of the second convex part 34 and improve the elasticity of the second convex part 34, so that in the process that the second convex part 34 extends into the shell 20 and abuts against the first tab 12, the second convex part 34 can release stress through deformation, the impact force is reduced, and the risk that the first tab 12 is crushed is reduced.

The second recess 35 and the second protrusion 34 may be formed by stamping the end cap 30. The greater the depth of the second recess 35 in the thickness direction Z, the greater the extent to which the second projection 34 projects from the inner surface 31a of the lid body.

On the premise of ensuring the protruding degree of the second convex part 34, the embodiment of the application further ensures the recessed degree of the second concave part 35 so as to improve the elasticity of the second convex part 34 and reduce the risk that the second convex part 34 crushes the first tab 12 in the assembling process.

In some embodiments, the outer side 341 of the second protrusion abuts against the inner surface of the housing 20 and is welded to the housing 20 to close the opening 21.

The outer side surface 341 of the second projection is a surface of the second projection 34 facing the side wall 22 of the housing 20. The outer side 341 of the second convex portion is a cylindrical surface, and optionally, the outer side 341 of the second convex portion is a cylindrical surface.

The portion of the second protrusion 34 extending into the housing 20 may be an interference fit, transition fit, or clearance fit with the housing 20. Alternatively, the portion of the second protrusion 34 extending into the housing 20 may be in interference fit with the housing 20, and the interference fit may increase the strength of the connection between the housing 20 and the end cap 30, improving the sealing performance.

Alternatively, the second projection 34 and the side wall 22 of the housing 20 are joined by laser welding. At the time of welding, laser light is irradiated to the boundary between the second projection 34 and the side wall 22, and the laser light melts and connects at least part of the outer side surface 341 of the second projection and part of the inner surface of the case 20. The outer side 341 of the second protrusion abuts against the inner surface of the case 20, so that the risk of burning the electrode assembly 10 when laser light is incident into the case 20 can be reduced.

Alternatively, the laser may also be irradiated on the outer surface of the side wall 22 facing away from the second convex portion 34.

In the present embodiment, welding can achieve sealing, reduce the risk of leakage of the electrolyte, and improve the connection strength and the flow-through capability between the second projection 34 and the case 20.

The second concave portion 35 can reduce the strength of the second convex portion 34 and increase the elasticity of the second convex portion 34, so that the second convex portion 34 can release the welding stress through deformation during welding the second convex portion 34 and the housing 20, thereby reducing the risk of deformation and cracking of the welding area and improving the sealing performance. The present embodiment further ensures the degree of depression of the second concave portion 35 on the premise of ensuring the degree of protrusion of the second convex portion 34, so as to improve the elasticity of the second convex portion 34, and enable the second convex portion 34 to release the welding stress through deformation.

In some embodiments, the cover body 31 is a flat plate structure. The inner surface 31a of the cap body and the outer surface 31b of the cap body are both planar and arranged in parallel.

Fig. 7 is a schematic cross-sectional view of a battery cell provided in accordance with other embodiments of the present application; fig. 8 is an enlarged schematic view of the battery cell shown in fig. 7 at a circle frame B.

As shown in fig. 7 and 8, in some embodiments, the first protrusion 32 surrounds the outside of the cap body 31. In other words, the first protrusion 32 is an annular structure surrounding the outside of the cap body 31.

In some embodiments, the portion of the first protrusion 32 extending into the housing 20 may be an interference fit, transition fit, or clearance fit with the housing 20. Alternatively, the portion of the first protrusion 32 extending into the housing 20 may be in an interference fit with the housing 20, and the interference fit may increase the strength of the connection between the housing 20 and the end cap 30, improving the sealing performance.

In some embodiments, the outer side of the first protrusion 32 abuts the inner surface of the housing 20 and is used for welding with the housing 20 to close the opening 21.

In other embodiments, the end cap 30 further includes an extension 36 surrounding the outside of the first protrusion 32, and a surface of the extension 36 facing the first tab 12 is abutted against an end surface of the housing 20 surrounding the opening 21 and welded to close the opening 21.

The extension portion 36 includes an inner surface and an outer surface oppositely disposed in the thickness direction Z, and the inner surface of the extension portion 36 faces the first tab 12. Optionally, the extension 36 is an annular plate-like structure, and both the inner surface of the extension 36 and the outer surface of the extension 36 are planar.

The extension 36 and the housing 20 are arranged in the thickness direction Z, and the inner surface of the extension 36 may be disposed in parallel with the end surface of the housing 20.

Alternatively, at the time of welding, laser light is irradiated at the boundary between the end surface of the case 20 and the inner surface of the extension portion 36; after welding, at least part of the inner surface of the extension 36 and at least part of the end surface of the housing 20 are melted and joined together.

In this embodiment, when the end cap 30 and the housing 20 are assembled, the end surface of the housing 20 can perform a limiting function in the thickness direction Z, so that the risk that the end cap 30 is excessively inserted into the housing 20 is reduced, and the assembly efficiency is improved.

The cover body 31 may be flat as a whole or partially protruded.

In some embodiments, the cover body 31 includes a main plate body 313 and a third protrusion 314, the main plate body 313 surrounds an outer side of the third protrusion 314, the first protrusion 32 surrounds the outer side of the main plate body 313, and the weak portion 311 is formed at the third protrusion 314. The main plate body 313 includes a first inner surface 313a and a first outer surface 313b that are oppositely disposed, the first inner surface 313a facing the electrode assembly 10, the first protrusion 32 and the third protrusion 314 each protrude from the first inner surface 313a in a direction facing the electrode assembly 10, and a tip end surface of the first protrusion 32 is closer to the first tab 12 than a tip end surface of the third protrusion 314 to form an avoidance gap G for avoiding the weak portion 311 between the current collecting member 50 and the third protrusion 314.

The main plate body 313 has a plate-like structure, and a first inner surface 313a and a first outer surface 313b are disposed opposite to each other in the thickness direction Z. Optionally, the main plate body 313 is a flat plate structure, and the first inner surface 313a and the first outer surface 313b are both planar and arranged in parallel.

Alternatively, the tip end surface of the first projection 32 and the tip end surface of the third projection 314 are both planar and arranged in parallel.

The inner surface of the cap body includes a first inner surface 313a, a tip end surface of the third protrusion 314, and a side surface of the third protrusion 314, wherein the side surface of the third protrusion 314 connects the first inner surface 313a and the tip end surface of the third protrusion 314. At least a portion of the first protrusion 32 protrudes from the tip end surface of the third protrusion 314 in a direction facing the electrode assembly 10.

A small amount of gas may be released from the battery cell 7 during normal circulation, and the gas may increase the internal pressure of the battery cell 7, thereby causing a risk of deformation of the end cap 30; when the end cap 30 is deformed, the weak portion 311 is easily deformed, so that the weak portion 311 may be broken when the internal pressure of the battery cell 7 does not reach a threshold value, resulting in failure of the battery cell 7.

In the present embodiment, the third protrusion 314 is disposed in the middle of the end cap 30, so that the strength of the end cap 30 can be increased, and the deformation of the end cap 30 can be reduced. Since third projecting portion 314 is in a projecting state and is not easily deformed, by providing weak portion 311 on third projecting portion 314, creep of weak portion 311 can be reduced, thereby reducing the risk of failure of weak portion 311.

The present embodiment reduces the risk of the current collecting member 50 blocking the exhaust passage when the weak portion 311 is broken by forming the escape gap G between the third protrusion 314 and the current collecting member 50, ensures smooth exhaust, and reduces the safety risk.

In some embodiments, a third concave portion 315 that is depressed from the first outer surface 313b in a direction facing the electrode assembly 10 is formed on the cap body 31 at a position corresponding to the third convex portion 314, and the third convex portion 314 forms a weak portion 311 at a region opposite to a bottom surface of the third concave portion 315.

A portion of the third convex portion 314 between the bottom surface of the third concave portion 315 and the tip end surface of the third convex portion 314 is provided with a weak portion 311. Alternatively, the bottom surface of the third recess 315 and the top end surface of the third protrusion 314 are both planar and arranged in parallel.

The weak portion 311 is formed in a region of the third protrusion 314 opposite to the bottom surface of the third recess 315, which may increase the distance of the weak portion 311 from other external members, reducing the risk of the weak portion 311 being crushed by the external members.

Fig. 9 is a schematic cross-sectional view of a battery cell provided in accordance with still other embodiments of the present application; fig. 10 is an enlarged schematic view of the battery cell shown in fig. 9 at block C.

As shown in fig. 9 and 10, in some embodiments, the first protrusion 32 surrounds the outside of the cap body 31, and the current collecting member 50 serves to connect the cap body 31 and the first tab 12 to electrically connect the end cap 30 and the first tab 12.

In some embodiments, the current collecting member 50 includes a first current collecting part 51 and a second current collecting part 52 connected to the first current collecting part 51, the first current collecting part 51 is used to connect the first tab 12 so that the current collecting member 50 and the first tab 12 are electrically connected, and the second current collecting part 52 is used to connect the cap body 31 so that the current collecting member 50 and the end cap 30 are electrically connected. The first collecting portion 51 is protrudingly provided on a surface of the second collecting portion 52 facing the electrode assembly 10, and an avoiding recess 53 recessed from a surface of the second collecting portion 52 facing away from the electrode assembly 10 in a direction facing the electrode assembly 10 is formed at a position of the collecting member 50 corresponding to the first collecting portion 51 to form an avoiding gap G between the collecting member 50 and the cap body 31.

In the present embodiment, by providing the avoiding recess 53 to form the avoiding gap G and avoid the first collecting portion 51 from abutting on the cap body 31, the risk of the first collecting portion 51 pressing the weak portion 311 is reduced, and safety is improved.

The first current collecting portion 51 supports the middle region of the first tab 12, and the first protrusion 32 supports the edge region of the first tab 12, so that the stress uniformity of the first tab 12 can be improved, and the risk of the pole pieces of the electrode assembly 10 shifting and misplacing in the thickness direction Z can be reduced.

In some embodiments, the first current collecting portion 51 is adapted to abut and be welded to the first tab 12, and the second current collecting portion 52 is adapted to abut and be welded to the cap body 31.

The avoiding recess 53 can reduce the thickness of the first current collecting portion 51 to reduce the welding power required for welding the first current collecting portion 51 to the first tab 12, reduce heat generation, and reduce the risk of other components (e.g., the separator) being burned.

In some embodiments, the second header 52 is a flat plate structure surrounding the outside of the first header 51.

The cover body 31 may be flat as a whole or partially protruded.

In some embodiments, the cover body 31 includes a main plate body 313 and a third protrusion 314, the main plate body 313 surrounds an outer side of the third protrusion 314, the first protrusion 32 surrounds the outer side of the main plate body 313, and the weak portion 311 is formed at the third protrusion 314. The main plate body 313 includes a first inner surface 313a and a first outer surface 313b that are oppositely disposed, the first inner surface 313a faces the electrode assembly 10, the first protrusion 32 and the third protrusion 314 each protrude from the first inner surface 313a in a direction facing the electrode assembly 10, and a tip end surface of the first protrusion 32 is closer to the first tab 12 than a tip end surface of the third protrusion 314 to form an avoidance gap G for avoiding the weak portion 311 between the current collecting member 50 and the third protrusion 314.

The avoidance concave portion 53 may provide a convex space for the third convex portion 314, for example, at least a portion of the third convex portion 314 protrudes into the avoidance concave portion 53.

In some embodiments, the first tab 32 is adapted to abut and be welded to the first tab 12 to effect electrical connection of the end cap 30 and the first tab 12.

In the present embodiment, the end cap 30 may be directly electrically connected to the first tab 12 through the first protrusion 32, thereby simplifying the structure of the battery cell 7, for example, the current collecting member 50 may be omitted.

Fig. 11 is a schematic flow chart of a method for manufacturing a battery cell according to some embodiments of the present disclosure.

As shown in fig. 11, the method for manufacturing a battery cell according to the embodiment of the present application includes:

s100, providing a shell, wherein the shell is provided with an opening;

s200, providing an electrode assembly, and installing the electrode assembly into the shell, wherein the electrode assembly is provided with a first tab at one end facing the opening;

s300, providing an end cover, wherein the end cover comprises a cover body and a first convex part connected to the cover body, and the cover body is provided with a weak part;

s400, connecting the end cover to the shell so as to cover the opening with the end cover;

wherein the end cap is configured to rupture along the frangible portion to vent internal pressure of the battery cell when the internal pressure reaches a threshold value; the first protrusion protrudes from the cap body in a direction facing the electrode assembly and supports the first tab such that an avoidance space for avoiding the weak portion is formed between the first tab and the cap body.

For the structure of the battery cell manufactured by the above method, reference may be made to the battery cells provided in the above embodiments.

When the battery cell is assembled based on the above-described method for manufacturing the battery cell, the steps need not be performed sequentially, that is, the steps may be performed in the order mentioned in the embodiments, may be performed in an order different from the order mentioned in the embodiments, or may be performed simultaneously. For example, steps S100 and S300 may be executed simultaneously without being performed sequentially.

Fig. 12 is a schematic block diagram of a system for manufacturing a battery cell provided in some embodiments of the present application.

As shown in fig. 12, an embodiment of the present application further provides a system 90 for manufacturing a battery cell, including:

a first providing means 91 for providing a housing having an opening;

a second supply device 92 for supplying an electrode assembly provided with a first tab at an end facing the opening and mounting the electrode assembly in the case;

a third supplying means 93 for supplying an end cap including a cap body provided with a weak portion and a first convex portion connected to the cap body;

an assembly device 94 for connecting the end cap to the housing so that the end cap covers the opening;

wherein the end cap is configured to rupture along the frangible portion to vent internal pressure of the battery cell when the internal pressure reaches a threshold value; the first protrusion protrudes from the cap body in a direction facing the electrode assembly and supports the first tab such that an avoidance space for avoiding the weak portion is formed between the first tab and the cap body.

For the structure of the battery cell manufactured by the manufacturing system, reference may be made to the battery cell provided in each of the above embodiments.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be equivalently replaced, but the modifications or the replacements do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (24)

1. A battery cell, comprising:

a housing having an opening;

an electrode assembly housed in the case, the electrode assembly including a main body portion and a first tab provided on a side of the main body portion facing the opening; and

an end cap for covering the opening, the end cap including a cap body and a first protrusion connected to the cap body, the cap body being provided with a weak portion, the end cap being configured to rupture along the weak portion when an internal pressure of the battery cell reaches a threshold value to discharge the internal pressure;

wherein the first protrusion protrudes from the cover body in a direction facing the electrode assembly, and supports the first tab such that an avoidance space for avoiding the weak portion is formed between the first tab and the cover body.

2. The battery cell as recited in claim 1, wherein a first recess recessed from an outer surface of the cap body in a direction facing the electrode assembly is formed at a position corresponding to the first protrusion on the end cap, and a bottom surface of the first recess is closer to the first tab than an inner surface of the cap body.

3. The battery cell as recited in claim 1, wherein the first tab is configured to abut and be welded to the first tab to electrically connect the end cap to the first tab.

4. The battery cell as recited in claim 1 further comprising a current collecting member disposed between the end cap and the first tab;

the current collecting component is used for connecting the end cover and the first tab to realize the electrical connection of the end cover and the first tab;

the avoiding gap is located between the current collecting member and the cap body in a thickness direction of the end cap.

5. The battery cell as recited in claim 4 wherein the current collecting member covers the weak portion in a thickness direction of the end cap to space the weak portion from the first tab.

6. The battery cell as recited in claim 4 wherein the first tab surrounds the outside of the cap body and the current collecting member is configured to connect the cap body to the first tab to electrically connect the end cap to the first tab.

7. The battery cell as recited in claim 6 wherein the current collecting member includes a first current collecting portion for connecting the first tab to electrically connect the current collecting member and the first tab and a second current collecting portion connected to the first current collecting portion for connecting the cap body to electrically connect the current collecting member and the end cap;

the first current collecting portion is convexly arranged on the surface, facing the electrode assembly, of the second current collecting portion, and an avoiding concave portion which is sunken from the surface, facing the electrode assembly, of the second current collecting portion in the direction facing the electrode assembly is formed in the position, corresponding to the first current collecting portion, of the current collecting member, so that the avoiding gap is formed between the current collecting member and the cover body.

8. The battery cell as recited in claim 7 wherein the first current collector portion is adapted to abut and be welded to the first tab and the second current collector portion is adapted to abut and be welded to the cap body.

9. The battery cell as recited in claim 4 wherein at least a portion of the current collecting member is located between the first tab and the first tab;

the first tab is supported by the first tab by the current collecting member.

10. The battery cell as recited in claim 9 wherein a portion of the current collecting member is adapted to abut and be welded to the first tab and another portion of the current collecting member is adapted to abut and be welded to the first tab.

11. The battery cell as recited in claim 10 wherein the current collecting member is a flat plate structure.

12. The battery cell as recited in claim 9 wherein the first protrusion surrounds an exterior side of the cover body.

13. The battery cell of claim 9, wherein the cover body surrounds an outside of the first protrusion.

14. The battery cell as recited in claim 13 wherein the end cap further comprises a second protrusion that surrounds the outside of the cap body;

the second protrusion protrudes from the inner surface of the cap body in a direction facing the electrode assembly, and a tip end surface of the second protrusion is closer to the first tab than a tip end surface of the first protrusion, so that the second protrusion abuts against the first tab and serves to support the first tab.

15. The battery cell as recited in claim 14, wherein a second recess recessed from the outer surface of the cap body in a direction facing the electrode assembly is formed at a position of the end cap corresponding to the second protrusion, and a bottom surface of the second recess is closer to the first tab than an inner surface of the cap body.

16. The battery cell as recited in claim 14 wherein the outer side of the second protrusion abuts the inner surface of the housing and is configured to be welded to the housing to close the opening.

17. The battery cell of any of claims 6-16, wherein the cover body is a flat plate structure.

18. The battery cell according to any one of claims 6 to 12, wherein the cover body includes a main plate body that surrounds an outer side of a third convex portion, and a first convex portion that surrounds the outer side of the main plate body, the weak portion being formed at the third convex portion;

the main plate body includes a first inner surface and a first outer surface that are disposed opposite to each other, the first inner surface facing the electrode assembly, the first protrusion and the third protrusion each protruding from the first inner surface in a direction facing the electrode assembly, and a tip end surface of the first protrusion is closer to the first tab than a tip end surface of the third protrusion to form the avoiding gap for avoiding the weak portion between the current collecting member and the third protrusion.

19. The battery cell as recited in claim 18, wherein a third concave portion that is concave from the first outer surface in a direction facing the electrode assembly is formed on the cover body at a position corresponding to the third convex portion, and the third convex portion forms the weak portion at a region opposite to a bottom surface of the third concave portion.

20. The battery cell as recited in claim 1 wherein the end cap electrically connects the first tab and the housing.

21. The battery cell as recited in claim 20, wherein the case includes a side wall extending in a thickness direction of the end cap and disposed around an outer circumference of the electrode assembly, and a bottom wall connected to the side wall, the bottom wall being provided with an electrode lead-out hole;

the electrode assembly further comprises a second tab, and the first tab and the second tab have opposite polarities and are respectively positioned at two ends of the electrode assembly;

the battery unit further comprises an electrode terminal installed in the electrode leading-out hole, and the electrode terminal is electrically connected to the second tab.

22. The battery cell as recited in claim 21 wherein the bottom wall and the side wall are integrally formed.

23. A battery comprising a plurality of battery cells according to any of claims 1-22.

24. An electrical device comprising a battery according to claim 23 for providing electrical energy.

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