BATTERY CELL, BATTERY, ELECTRICAL DEVICE, AND MANUFACTURING DEVICE AND METHOD FOR BATTERY CELL

A battery cell includes an electrode assembly, a case, an end cover, a first current collecting member, and a second current collecting member, where the case is provided with a first position-limiting portion protruding from the inner side face; the first current collecting member is used for connecting tabs; the second current collecting member is used for connecting the first current collecting member and the first position-limiting portion; and the first current collecting member includes a first region overlapping with the first position-limiting portion along a thickness direction and a second region not overlapping with the first position-limiting portion, the first region and the second region both being welded to the tabs. The first region can be welded to the tab of an outer ring layer, and the second region can be welded to the tab of an inner ring layer, which enables uniform current conduction to be realized.

TECHNICAL FIELD

The present application relates to the technical field of batteries, and in particular, to a battery cell, a battery, an electrical device, and a manufacturing device and method for a battery cell.

BACKGROUND

At present, the batteries often used in vehicles are generally lithium-ion batteries, which, as a kind of rechargeable battery, have the advantages of small size, high energy density, high power density, high number of cycles and long storage time.

The battery cell generally includes a case and an electrode assembly, where the case is used to accommodate the electrode assembly and the electrolyte, and the electrode assembly generally includes a positive electrode plate and a negative electrode plate, with electrical energy being generated by the movement of metal ions (e.g., lithium ions) between the positive electrode plate and the negative electrode plate.

For a general battery cell, the electrode assembly needs to be electrically connected to the case to enable the case to serve as a positive output electrode or a negative output electrode of the battery cell. At present, it is inconvenient to implement the electrical connection between the electrode assembly and the case.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a battery cell, a battery, an electrical device, and a manufacturing device and method for a battery cell, so as to enable easy electrical connection between an electrode assembly and a case.

In a first aspect, embodiments of the present application provide a battery cell including an electrode assembly, a case, an end cover, a first current collecting member, and a second current collecting member, where the electrode assembly has tabs; the case has an opening, the case is used for housing the electrode assembly within the case, and the case is provided with a first position-limiting portion protruding from the inner side face; the end cover is used for covering the opening, the first position-limiting portion being used for limiting movement of the end cover towards a direction close to the electrode assembly; the first current collecting member is disposed on the side of the first position-limiting portion facing the electrode assembly along a thickness direction of the end cover, the first current collecting member being used for connecting the tabs; and the second current collecting member is disposed on the side of the first current collecting member facing away from the electrode assembly along the thickness direction, the second current collecting member being used for connecting the first current collecting member and the first position-limiting portion, where the first current collecting member includes a first region overlapping with the first position-limiting portion along the thickness direction and a second region not overlapping with the first position-limiting portion along the thickness direction, the first region and the second region both being welded to the tabs.

In the above technical solution, the first connecting member includes a first region overlapping with the first position-limiting portion along the thickness direction of the end cover and a second region not overlapping with the first position-limiting portion along the thickness direction of the end cover, where the first region can be welded to the tab of an outer ring layer, and the second region can be welded to the tab of an inner ring layer, so that the tabs of the inner ring layer and the outer ring layer can both be connected to the first current collecting member, which enables uniform current conduction to be realized, so as to avoid the problem of excessive local overcurrent due to the failure of the tab of the outer ring layer to be connected to the current collecting member, thereby reducing the risk of severe polarization of the tab of the outer ring layer in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation due to polarization. In addition, since the first current collecting member and the second current collecting member are provided in a split manner, it is possible to first connect the first current collecting member to the tab without being restricted by the structure of the case, and then connect the first current collecting member to the first position-limiting portion of the case by the second current collecting member, thereby conveniently realizing the connection of the electrode assembly and the case.

In some embodiments of the first aspect of the present application, the second current collecting member includes a body portion and a connecting portion, where the body portion is stacked with the first current collecting member along the thickness direction, the body portion being used for connecting the side of the first current collecting member facing away from the electrode assembly; and the connecting portion is connected to the body portion, a part of the connecting portion extending to the side of the first position-limiting portion in its protruding direction to effect a connection between the first current collecting member and the first position-limiting portion.

In the above technical solution, the body portion is stacked with the first current collecting member along the thickness direction and is electrically connected to the first current collecting member, which can improve the current conduction capability of the battery cell. A part of the connecting portion extends to the side of the first position-limiting portion in its protruding direction, thereby effecting a connection between the first current collecting member and the first position-limiting portion, which increases the contact area between the second current collecting member and the first position-limiting portion, so as to increase the overcurrent area between the case and the second current collecting member.

In some embodiments of the first aspect of the present application, the connecting portion includes a first connecting portion and a second connecting portion, where the first connecting portion is used for abutting against the side of the first position-limiting portion in its protruding direction; and the second connecting portion is connected to the end of the first connecting portion facing away from the body portion, the second connecting portion being used for abutting against the side of the first position-limiting portion facing away from the electrode assembly.

In the above technical solution, the first connecting portion abuts against the side of the first position-limiting portion in its protruding direction, and the second connecting portion abuts against the side of the first position-limiting portion facing away from the electrode assembly, which improves the stability of the connection between the connecting portion and the first position-limiting portion, and can also increase the contact area between the second current collecting member and the first position-limiting portion, so as to increase the overcurrent area between the case and the second current collecting member.

In some embodiments of the first aspect of the present application, the first connecting portion extends along the thickness direction.

In the above technical solution, the first connecting portion extends along the thickness direction of the end cover, such that the distance is shortest when the first extension portion extends to abut against the side of the first position-limiting portion that is in its protruding direction, thereby reducing the amount of internal space of the battery cell occupied by the first connecting portion.

In some embodiments of the first aspect of the present application, the first connecting portion is a closed-ring structure extending along a circumferential direction of the case.

In the above technical solution, the first connecting portion is of a closed-ring structure, which can increase the contact area between the first connecting portion and the first position-limiting portion, thereby increasing the overcurrent area between the case and the second current collecting member.

In some embodiments of the first aspect of the present application, the second connecting portion is a closed-ring structure surrounding the edge of the first connecting portion.

In the above-described technical solution, the second connecting portion is of a closed-ring structure, which can increase the contact area between the second connecting portion and the first position-limiting portion, thereby increasing the overcurrent area between the case and the second current collecting member.

In some embodiments of the first aspect of the present application, the first current collecting member and the second current collecting member form a plug-in fit along the thickness direction.

In the above technical solution, the first current collecting member and the second current collecting member form a plug-in fit along the thickness direction of the end cover, which enables plug-in positioning of the first current collecting member and the second current collecting member, thereby enabling improvement of the stability of the relative positional relationship between the first current collecting member and the second current collecting member, and facilitating welding of the first current collecting member and the second current collecting member and improving the stability of the electrical energy output.

In some embodiments of the first aspect of the present application, the first current collecting member is formed with a groove on the side facing the end cover, a part of the second current collecting member being arranged in the groove.

In the above technical solution, the second current collecting member is plugged into the groove on the side of the first current collecting member facing the end cover, which not only enables plug-in positioning of the first current collecting member and the second current collecting member, thereby enabling improvement of the stability of the relative positional relationship between the first current collecting member and the second current collecting member, and facilitating welding of the first current collecting member and the second current collecting member and improving the stability of the electrical energy output, but also reduces the amount of space occupied by the first current collecting member and the second current collecting member in the thickness direction of the end cover. It also makes the position where the first current collecting member is provided with the groove have a smaller thickness, which facilitates the welding of the first current collecting member to the tabs.

In some embodiments of the first aspect of the present application, the first current collecting member is provided with a central hole penetrating through the first current collecting member along the thickness direction, and the first current collecting member is formed with a guide groove on the side facing the electrode assembly, the guide groove being configured to guide, towards the outer periphery, electrolyte entering the electrode assembly through the central hole.

In the above technical solution, the guide groove is capable of guiding the electrolyte of the central hole to a region other than the central hole, so that the electrolyte is uniformly distributed inside the battery cell, thereby sufficiently and uniformly infiltrating the electrode assembly and reducing the possibility of lithium precipitation of the battery cell.

In some embodiments of the first aspect of the present application, the case is formed with a first concave portion recessed inwardly from the outer peripheral wall of the case, the case is formed with a first position-limiting portion protruding from the inner peripheral wall of the case at a position corresponding to the first concave portion, and the first concave portion and the first position-limiting portion are both annular structures.

In the above technical solution, forming the first position-limiting portion in the inner wall of the case has a large machining difficulty, while the difficulty of forming the first concave portion in the outer peripheral wall of the case is lower compared to the difficulty of forming the first position-limiting portion directly in the inner peripheral wall of the case; therefore, the difficulty of molding the first position-limiting portion is lowered by forming the first position-limiting portion protruding from the inner peripheral wall of the case at the position of the case that corresponds to the first concave portion.

In some embodiments of the first aspect of the present application, the case has a second position-limiting portion; and in the thickness direction of the end cover, the second position-limiting portion and the first position-limiting portion are used for jointly limiting movement of the end cover relative to the case in the thickness direction.

In the above technical solution, the second position-limiting portion and the first position-limiting portion cooperate to jointly limit movement of the end cover relative to the case in the thickness direction of the end cover, so as to maintain a stable connection relationship between the end cover and the case.

In some embodiments of the first aspect of the present application, the second position-limiting portion is a flanging structure in which the case is folded inward at the opening position.

In the above technical solution, the second position-limiting portion is a flanging structure in which the case is folded inward at the opening position, which means that the second position-limiting portion is a part of the case, so as to enable the second position-limiting portion to stably position-limit the end cover on the side of the end cover facing away from the electrode assembly. Moreover, the second position-limiting portion is a part of the case, which can also reduce the connecting relationship of the case and thus improve the structural strength of the case.

In some embodiments of the first aspect of the present application, the battery cell further includes a sealing member, the sealing member being used between the first position-limiting portion and the end cover and between the second position-limiting portion and the end cover.

In the above technical solution, the sealing performance of the battery cell is improved by means of the sealing member being used between the first position-limiting portion and the end cover and between the second position-limiting portion and the end cover.

In a second aspect, embodiments of the present application provide a battery including a battery cell described in any of the embodiments of the first aspect.

In the above technical solution, the battery cell includes a first current collecting member and a second current collecting member, where the first current collecting member is connected to the tabs, and the second current collecting member connects the first current collecting member and the first position-limiting portion of the case. The first region of the first current collecting member can be welded to the tab of an outer ring layer, and the second region of the first current collecting member can be welded to the tab of an inner ring layer, so that the tabs of the inner ring layer and the outer ring layer can both be connected to the first current collecting member, which enables uniform current conduction to be realized, so as to avoid the problem of excessive local overcurrent due to the failure of the tab of the outer ring layer to be connected to the current collecting member, thereby reducing the risk of severe polarization of the tab of the outer ring layer in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation due to polarization, thus improving the safety performance of the battery.

In a third aspect, embodiments of the present application provide an electrical device, including a battery provided by any one of the embodiments of the second aspect.

In the above technical solution, the battery does not have the problem of local overcurrent due to the failure of the outer ring tab to be connected to the current collecting member, thereby reducing the risk of severe polarization of the outer ring tab in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation, thus improving the electrical safety in the electrical device.

In a fourth aspect, embodiments of the present application provide a manufacturing device for a battery cell, including a providing apparatus and an assembling apparatus, the providing apparatus being configured to provide an electrode assembly, a case, an end cover, a first current collecting member, and a second current collecting member, where the electrode assembly has tabs; the case has an opening, the case houses the electrode assembly, and the case is provided with a first position-limiting portion protruding from the inner side face, the first position-limiting portion being used for limiting movement of the end cover towards a direction close to the electrode assembly; and the end cover is used for covering the opening; and the assembling apparatus is configured to accommodate the electrode assembly within the case, to connect the first current collecting member to the tabs, to connect the second current collecting member to the first current collecting member and the first position-limiting portion, and to cover the opening with the end cover, where the first current collecting member includes a first region overlapping with the first position-limiting portion along a thickness direction of the end cover and a second region not overlapping with the first position-limiting portion along the thickness direction, the first region and the second region both being welded to the tabs.

In a fifth aspect, embodiments of the present application provide a manufacturing method for a battery cell, the manufacturing method including:providing an electrode assembly, a case, an end cover, a first current collecting member, and a second current collecting member, wherein the electrode assembly has tabs; and the case has an opening, the case is used as a housing for accommodating the electrode assembly, and the case is provided with a first position-limiting portion protruding from the inner side face, the first position-limiting portion being used for limiting movement of the end cover towards a direction close to the electrode assembly;connecting the first current collecting member to the tabs;connecting the second current collecting member to the first current collecting member;placing the electrode assembly within the case and connecting the second current collecting member to the first position-limiting portion; andcovering the opening with the end cover,wherein the first current collecting member comprises a first region overlapping with the first position-limiting portion along a thickness direction of the end cover and a second region not overlapping with the first position-limiting portion along the thickness direction, the first region and the second region both being welded to the tabs.

DETAILED DESCRIPTION

For the objects, technical solutions and advantages of the embodiments of the present application to be clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application, and it is apparent that the described embodiments are a part of the examples of the present application rather than all the embodiments. The assembly of the examples of the present application generally described and illustrated in the drawings herein can be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is claimed, but merely to indicate selected embodiments of the present application. All the other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without any creative effort shall fall within the scope of protection of the present application.

It should be noted that, without conflict, embodiments in the present application and features in the embodiments may be combined together.

It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship is indicated as being based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present application is customarily placed in use, or as customarily understood by those skilled in the art, solely for the purpose of facilitating the description of the present application and simplifying the description, but do not indicate or imply that the apparatuses or elements referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore cannot be construed as a limitation of the present application. In addition, the terms “first”, “second” and “third” are only used to distinguish the description, and cannot be construed as indicating or implying relative importance.

At present, from the perspective of the development of the market situation, power batteries are increasingly more widely used. Power batteries are not only applied in energy storage power source systems such as water, fire, wind and solar power stations, but also widely applied in electric transport tools, such as electric bicycles, electric motorcycles, and electric vehicles, as well as many fields, such as military equipment and aerospace. With the continuous expansion of the application field of the power batteries, the market demand is also constantly expanding.

In the prior art, the battery cell includes an electrode assembly, a case, an end cover, and a current collecting member. The electrode assembly is accommodated within the case, and the case is provided with a first position-limiting portion protruding from the inner side face, the first position-limiting portion being used for limiting movement of the end cover along a thickness direction thereof towards a direction close to the electrode assembly when the end cover covers the opening of the case. The current collecting member is provided on the side of the tab facing the end cover. The current collecting member includes a first current collecting portion and a second current collecting portion, where the first current collecting portion is used for welding to the tab, and the second current collecting portion is connected to the first current collecting portion and extends in the thickness direction of the end cover towards a direction close to the end cover until it abuts against an inner side face of the first position-limiting portion along a protruding arrangement direction thereof to realize an electrical connection of this tab with the first position-limiting portion via the current collecting member.

The inventors have found that since the second current collecting portion is abutted against the inner side face of the first position-limiting portion along the protruding arrangement direction thereof, the size of the part of the first current collecting portion which is on the outer side of the second current collecting portion is very small or even non-existent, resulting in failure of the part of this tab which is located on the outer side of the second current collecting portion to be welded to the first current collecting portion; or the tab is a kneaded flat tab, and the tab on the outer side of the second current collecting portion has a large slope, resulting in failure of that part of the tab to be welded to the first current collecting portion, which can easily lead to the problem of excessive local overcurrent due to the failure of the part of the tab to be connected to the current collecting member, and cause a severe polarization of the unwelded side of the tab in the cyclic charging and discharging process, or even worse, lead to lithium precipitation on the tab side, which seriously affects the safety performance of the battery cell.

Based on the above considerations, in order to alleviate the problem of severe polarization of the tab of the outer ring layer in the cyclic charging and discharging process caused by excessive local overcurrent produced due to the failure of the tab of the outer ring layer to be welded to the current collecting member, embodiments of the present application provide a battery cell, the battery cell including a first current collecting member and a second current collecting member provided in a split manner, where the first current collecting member is used for connecting to the tabs of the electrode assembly, and the first current collecting member and the first position-limiting portion are connected via a second current collecting member; and the first current collecting member includes a first region overlapping with the first position-limiting portion along the thickness direction of the end cover and a second region not overlapping with the first position-limiting portion along the thickness direction of the end cover, the first region and the second region both being welded to the tabs, where the first region can be welded to the tab of the outer ring layer, and the second region can be welded to the tab of the inner ring layer, so that the tab of the inner ring layer and the tab of the outer ring layer can both be connected to the first current collecting member, which enables uniform current conduction to be realized, so as to avoid the problem of excessive local overcurrent due to the failure of the tab of the outer ring layer to be connected to the current collecting member, thereby reducing the risk of severe polarization of the tab of the outer ring layer in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation due to polarization. In addition, since the first current collecting member and the second current collecting member are provided in a split manner, it is possible to first connect the first current collecting member to the tab without being restricted by the structure of the case, and then connect the first current collecting member to the first position-limiting portion222of the case by the second current collecting member, thereby conveniently realizing the connection of the electrode assembly and the case.

The battery cells disclosed in embodiments of the present application can be used in, but are not limited to, an electrical apparatus, such as a vehicle, a ship, or an aircraft. A battery, or the like, that has the battery cell disclosed in the present application may be used to form a power supply system for such an electrical apparatus. In this way, it is beneficial to alleviate the problem of severe polarization of the tab of the outer ring layer in the cyclic charging and discharging process caused by excessive local overcurrent due to the failure of the tab of the outer ring layer to be welded to the current collecting member, thereby reducing the risk of lithium precipitation of the battery cell, and improving the safety performance of the battery cell.

The technical solutions described in embodiments of the present application are applicable to the battery and an electrical device using the battery.

The electrical device may be a vehicle, a mobile phone, a portable device, a laptop, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be an all-electric vehicle, a hybrid electric vehicle, an extended-range vehicle, or the like. The spacecraft includes airplanes, rockets, space shuttles, spaceships, and the like. The electric toy includes fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric aircraft toys. The electric tool includes metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers. Embodiments of the present application do not impose special limitations on the above electrical device.

For the convenience of illustration, the following embodiments are illustrated with the electrical device being a vehicle1000as an example.

Referring toFIG.1,FIG.1is a structural schematic diagram of a vehicle1000according to some embodiments of the present application. The interior of the vehicle1000is provided with a battery100, and the battery100may be provided at the bottom or head or tail of the vehicle1000. The battery100may be used to supply power to the vehicle1000. For example, the battery100may be used as an operating power source of the vehicle1000.

The vehicle1000may further include a controller200and a motor300. The controller200is used to control the battery100to supply power to the motor300, for example, for the operating power demand when the vehicle1000is starting, navigating and driving.

In some embodiments of the present application, the battery100can not only be used as the operating power source of the vehicle1000, but also be used as a driving power source of the vehicle1000to replace or partially replace fuel or natural gas to provide driving power for the vehicle1000.

Please refer toFIG.2.FIG.2is a structural schematic diagram of a battery100provided according to some embodiments of the present application. The battery100includes a box body10and a battery cell20, the battery cell20being accommodated in the box body10.

The box body10is used to provide a mounting space11for the battery cell20. In some embodiments, the box body10may include a first part12and a second part13, the first part12and the second part13covering each other to define the mounting space11for accommodating the battery cell20. Of course, the connection between the first part12and the second part13may be sealed by a sealing member27(not shown), where the sealing member27may be a sealing ring, a sealant, or the like.

The first part12and the second part13may be of a variety of shapes, such as a rectangular solid, a cylinder, or the like. The first part12may be of a hollow structure that has an opening221on one side to form an accommodation cavity, and the second part13may also be of a hollow structure that has an opening221on one side to form an accommodation cavity, and the opening side of the second part13covers the opening side of the first part12to form the box body10having the mounting space11. Of course, alternatively, the first part12may be of a hollow structure that has an opening221on one side to form an accommodation cavity, and the second part13may be of a plate-like structure, and the second part13covers the opening side of the first part12to form the box body10with the mounting space11.

There may be one or more battery cell20in a battery100. If there are multiple battery cells20, the multiple battery cells20can be connected in series or parallel or in a mixed connection, where the mixed connection means that the multiple battery cells20are connected in both series and parallel. The multiple battery cells20can be directly connected together in series or in parallel or in mixed connection, and then the whole composed of the multiple battery cells20can be accommodated in the box body10; and of course, the multiple battery cells20can be connected in series or in parallel or in mixed connection to form a battery module first, then multiple battery modules can be connected in series or in parallel or in mixed connection to form a whole, and accommodated in the box body10. The battery cells20may be cylindrical, flat, rectangular, or in other shapes.FIG.2exemplarily illustrates a situation where the battery cell20is cylindrical.

In some embodiments, the battery100may also include a busbar component (not shown), and the multiple battery cells20may be electrically connected through the busbar component, so as to realize series, parallel or mixed connection of the multiple battery cells20.

Referring toFIGS.3,4, and5, whereFIG.3is a structural schematic diagram of a battery cell20provided in some embodiments of the present application,FIG.4is a cross-sectional view ofFIG.3, andFIG.5is an enlarged view at I inFIG.4. The battery cell20may include an electrode assembly21, a case22, an end cover23, a first current collecting member24, and a second current collecting member25, where the electrode assembly21has tabs211; the case22has an opening221, the case22being a housing that holds within itself the electrode assembly21, and the case22being provided with a first position-limiting portion222protruding from the inner side face; the end cover23is used for covering the opening221, the first position-limiting portion222being used for limiting movement of the end cover23towards a direction close to the electrode assembly21; the first current collecting member24is disposed on the side of the first position-limiting portion222facing the electrode assembly21along a thickness direction X of the end cover, the first current collecting member24being used for connecting the tabs211; and the second current collecting member25is disposed on the side of the first current collecting member24facing away from the electrode assembly21along the thickness direction, the second current collecting member25being used for connecting the first current collecting member24and the first position-limiting portion222, where the first current collecting member24includes a first region241overlapping with the first position-limiting portion222along the thickness direction and a second region242not overlapping with the first position-limiting portion222along the thickness direction, the first region241and the second region242both being welded to the tabs211.

The case22may be of a variety of shapes, such as a cylinder, a rectangular solid, or the like. The shape of the case22may be determined according to the specific shape of the electrode assembly21. For example, if the electrode assembly21is of a cylindrical structure, the case22may be of a cylindrical structure; and if the electrode assembly21is of a rectangular structure, the case22may be of a rectangular structure.FIG.3exemplarily illustrates a situation where the case22and the electrode assembly21are cylindrical.

The case22may also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, and aluminum alloy, which is not particularly limited in the embodiments of the present application.

For the thickness direction X of the end cover mentioned in the embodiments of the present application, if the battery cell20is of a cylindrical structure, the thickness direction X of the end cover is also the axial direction of the battery cell20. The first position-limiting portion222has a protruding arrangement direction perpendicular to the thickness direction X of the end cover.

The end cover23is used to cover the opening221of the case22to form a closed accommodation space (not shown), the accommodation space being used to accommodate the electrode assembly21. The accommodation space is also used to accommodate an electrolyte, such as an electrolyte solution.

It is noted that the number of the opening221of the case22may be one or two. If the number of the opening221of the case22is one, the number of the end cover23may also be one, and there may be one electrode terminal26provided in the end cover23, where the electrode terminal26is electrically connected to one of the positive tab and the negative tab of the electrode assembly21, and the other of the positive tab and the negative tab is electrically connected to the case22. The end cover23and the case22may be insulatively connected.

As shown inFIG.3, in some embodiments, the positive tab and the negative tab of the electrode assembly21are disposed at two opposite ends of the battery cell20in the axial direction, respectively. The number of the openings221of the case22is two, and the two openings221are disposed at two ends of the case22in the axial direction, respectively, the end cover23covering one of the openings221, and the other opening221allowing the electrode terminal26to pass through to be electrically connected to the tabs211. Among other things, the electrode terminal26and the tab211are connected via the current collecting member to realize the electrical connection between the electrode terminal26and the tab211.

As shown inFIG.5, the end cover23may also be provided with a pressure relief mechanism231, the pressure relief mechanism231being used to be actuated to relieve the internal pressure or temperature of the battery cell20when the pressure or temperature inside the battery cell20reaches a threshold. The threshold design varies according to different design requirements. The threshold may depend on the material of one or more of the positive electrode plate, the negative electrode plate, the electrolyte, and the separator in the battery cell20. The pressure relief mechanism231may take the form of, for example, an explosion-proof valve, an explosion-proof sheet, an air valve, a pressure relief valve, or a safety valve, and may specifically employ a pressure-sensitive or temperature-sensitive element or construction. That is to say, when the internal pressure or temperature of the battery cell20reaches a predetermined threshold, the pressure relief mechanism231performs an action, or a weak structure provided in the pressure relief mechanism231is broken, so as to form an opening221or channel through which the internal pressure or temperature can be relieved.FIG.5illustrates the situation where the pressure relief mechanism231is a weak portion formed on the end cover23by means of indentations or the like.

The electrode assembly21may include a positive electrode plate (not shown), a negative electrode plate (not shown), and a separator (not shown). The electrode assembly21may be a wound structure formed by winding the positive electrode plate, the separator, and the negative electrode plate, or may be a laminated structure formed by laminated arrangement of the positive electrode plate, the separator, and the negative electrode plate. The electrode assembly21further includes a positive tab and a negative tab, where the positive electrode current collector in the positive electrode plate that is not coated with the positive electrode active material layer can be used as the positive tab, and the negative electrode current collector in the negative electrode plate that is not coated with the negative electrode active material layer can be used as the negative tab.

The first current collecting member24is used to connect the tab211, and this tab211may be a positive tab or a negative tab, which means that it may be a positive tab of the first current collecting member24for connecting the electrode assembly21or a negative tab of the first current collecting member24for connecting the electrode assembly21. If it is the positive tab of the first current collecting member24that is used for connecting the electrode assembly21, after the second current collecting member25connects the first current collecting member24and the first position-limiting portion222, an electrical connection is realized between the case22and the positive tab of the electrode assembly21, then the case22serves as the positive electrode output end of the battery cell20, and the electrode terminal26at the other end of the case22is electrically connected to the negative tab of the electrode assembly21to form the negative electrode output end of the battery cell20. If it is the negative tab of the first current collecting member24that is used for connecting the electrode assembly21, after the second current collecting member25connects the first current collecting member24and the first position-limiting portion222, an electrical connection is realized between the case22and the negative tab of the electrode assembly21, then the case22serves as the negative electrode output end of the battery cell20, and the electrode terminal26at the other end of the case22is electrically connected to the positive tab of the electrode assembly21to form the positive electrode output end of the battery cell20.

Along the thickness direction X of the end cover, the tab211has a first tab211region (an outer ring layer tab211) overlapping with the first region241and a second tab211region (an inner ring layer tab211) overlapping with the second region242. If the first region241of the first current collecting member24is of a closed-ring structure surrounding the outer periphery of the second region242, then along the circumferential direction of the battery cell20, the first region241can be welded to the first tab211region at any position and the second region242can be welded to the second tab211region at any position.

The second current collecting member may be welded to, bonded to, or abutted against the first position-limiting portion222, thereby effecting an electrical connection of the tab211to the case22via the first current collecting member24and the second current collecting member25.

The first connecting member includes a first region241overlapping with the first position-limiting portion222along the thickness direction X of the end cover and a second region242not overlapping with the first position-limiting portion222along the thickness direction X of the end cover, where the first region241can be welded to the tab211of an outer ring layer, and the second region242can be welded to the tab211of an inner ring layer, so that the tabs211of the inner ring layer and the outer ring layer can both be connected to the first current collecting member24, which enables uniform current conduction to be realized, so as to avoid the problem of excessive local overcurrent due to the failure of the tab211of the outer ring layer to be connected to the current collecting member, thereby reducing the risk of severe polarization of the tab211of the outer ring layer in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation due to polarization. In addition, since the first current collecting member24and the second current collecting member25are provided in a split manner, it is possible to first connect the first current collecting member24to the tab211without being restricted by the structure of the case22, and then connect the first current collecting member24to the first position-limiting portion222of the case22by the second current collecting member25, thereby conveniently realizing the connection of the electrode assembly21and the case22.

Referring toFIG.5, in some embodiments, the second current collecting member25includes a body portion251and a connecting portion252, where the body portion251is stacked with the first current collecting member24along the thickness direction, the body portion251being used for connecting the side of the first current collecting member24facing away from the electrode assembly21; and the connecting portion252is connected to the body portion251, a part of the connecting portion252extending to the side of the first position-limiting portion222in its protruding direction to effect a connection between the first current collecting member24and the first position-limiting portion222.

The body portion251and the connecting portion252may be integrally molded. The body portion251and the connecting portion252may also be provided in a split manner and connected as an integral structure by means of a connection method such as welding, bonding, or the like.

In this embodiment, the thickness direction refers to the thickness direction X of the end cover. The body portion251is stacked with the first current collecting member24along the thickness direction, where along the thickness direction X of the end cover, the projection of the body portion251may completely overlap with the second region242of the first current collecting member24. In some other embodiments, along the thickness direction X of the end cover, a part of the projection of the body portion251may overlap with the first region241of the first current collecting member24, and the other part of the projection of the body portion251may overlap with the second region242.

The side of the first position-limiting portion222along the protruding direction thereof is the innermost side of the first position-limiting portion222. A part of the connecting portion252may be welded to, bonded to, or abutted against the innermost side of the first position-limiting portion222to realize the connection of the second current collecting member25with the first position-limiting portion222.

The body portion251is stacked with the first current collecting member24along the thickness direction and is electrically connected to the first current collecting member24, which can improve the current conduction capability of the battery cell20. A part of the connecting portion252extends to the side of the first position-limiting portion222in its protruding direction, thereby effecting a connection between the first current collecting member24and the first position-limiting portion222, which increases the contact area between the second current collecting member25and the first position-limiting portion222, so as to increase the overcurrent area between the case22and the second current collecting member25.

Referring in combination toFIGS.5,6, and7, whereFIG.6is an axonometric view of a second current collecting member25provided in some embodiments of the present application, andFIG.7is a cross-sectional view of the second current collecting member25inFIG.6. In some embodiments, the connecting portion252includes a first connecting portion2521and a second connecting portion2522, where the first connecting portion2521is used to abut against the side of the first position-limiting portion222in its protruding direction; and the second connecting portion2522is connected to the end of the first connecting portion2521facing away from the body portion251, and the second connecting portion2522is used to abut against the side of the first position-limiting portion222facing away from the electrode assembly21.

The first connecting portion2521is a part of the body portion251that extends towards the interior of the first position-limiting portion222, and the first connecting portion2521may be leaning against or welded to the innermost side of the first position-limiting portion222to effect abutment. The second connecting portion2522is a part that extends from the end of the first connecting portion2521facing away from the body portion251to the side of the first position-limiting portion222facing away from the electrode assembly21. The second connecting portion2522may be welded to or abutted against the first position-limiting portion222. The second position-limiting portion224is abutted against the side of the first position-limiting portion222that faces away from the electrode assembly21such that the connecting portion252is hooked up to the first position-limiting portion222. By way of example, the first connecting portion2521is of a cylindrical structure, and the second connecting portion2522is of an annular structure provided at the end of the first connecting portion2521far from the body portion251. The second connecting portion2522may be welded to the first position-limiting portion222by means of penetration welding.

The first connecting portion2521and the second connecting portion2522may be integrally molded. For example, the second connecting portion2522is a flanging structure formed by means of the connecting portion252being bent. The first connecting portion2521and the second connecting portion2522may also be provided in a split manner and connected as an integral structure by means of a connection method such as welding, bonding, or the like.

As shown inFIGS.8and9,FIG.8is a cross-sectional view of a battery cell20provided in some other embodiments of the present application, andFIG.9is an enlarged view at II inFIG.8. In some other embodiments, the connecting portion252may also include only the first connecting portion2521. Alternatively, the connecting portion252includes a first connecting portion2521and a second connecting portion2522, where the first connecting portion2521is not abutted against the first position-limiting portion222and the second connecting portion2522is abutted against the side of the first position-limiting portion222that faces away from the electrode assembly21.

Referring in combination toFIGS.9,10, and11, whereFIG.10is a structural schematic diagram of a second current collecting member25provided in some other embodiments of the present application, andFIG.11is a cross-sectional view of the second current collecting member25inFIG.10. In some embodiments, the edge of the body portion251may be radially beyond the outer peripheral face of the first connecting portion2521such that the body portion251includes a first body portion2511that surrounds the outer periphery of the first connecting portion2521and a second body portion2512that is disposed within the first connecting portion2521, where along the thickness direction X of the end cover, the projection of the first body portion2511overlaps with the first region241of the first current collecting member24, and the projection of the second body portion2512overlaps with the second region242of the first current collecting member24so that a part of the projection of the body portion251along the thickness direction X of the end cover overlaps with the first region241of the first current collecting member24, and the other part of the projection of the body portion251may overlap with the second region242.

The first connecting portion2521abuts against the side of the first position-limiting portion222in its protruding direction, and the second connecting portion2522abuts against the side of the first position-limiting portion222facing away from the electrode assembly21, which improves the stability of the connection between the connecting portion252and the first position-limiting portion222, and can also increase the contact area between the second current collecting member25and the first position-limiting portion222, so as to increase the overcurrent area between the case22and the second current collecting member25.

In some embodiments, the first connecting portion2521extends along the thickness direction (please refer toFIGS.5and9).

The first connecting portion2521is perpendicularly connected to the body portion251. In some other embodiments, the first connecting portion2521may also extend in other directions. For example, the first connecting portion2521is arranged at an acute angle to the body portion251, then the first connecting portion2521extends along a direction that is at an acute angle to the thickness direction X of the end cover until it abuts against the innermost side face of the first position-limiting portion222, or the first connecting portion2521is bent with a certain curvature and then abuts against the first position-limiting portion222.

The first connecting portion2521extends along the thickness direction X of the end cover, such that the distance is shortest when the first extension portion extends to abut against the side of the first position-limiting portion222that is in its protruding direction, thereby reducing the amount of internal space of the battery cell20occupied by the first connecting portion2521.

Referring toFIG.6, in some embodiments, the first connecting portion2521is a closed-ring structure extending along a circumferential direction of the case22.

By way of example, the first connecting portion2521is of a cylindrical structure, and the first connecting portion2521is arranged coaxially with the electrode assembly21. The second connecting portion2522is connected to the end of the first connecting portion2521facing away from the body portion251, and the first connecting portion2521is beyond the outer peripheral face of the first connecting portion2521in a direction perpendicular to the axial direction of the first connecting portion2521and extends to the side of the first position-limiting portion222facing away from the electrode assembly21. Among other things, the outer peripheral face of the first connecting portion2521is a surface of the first connecting portion2521that is radially far from its central axis.

In other embodiments, the first connecting portion2521may also be of a non-closed-ring structure, for example, the first connecting portion2521is C-shaped.

The first connecting portion2521is of a closed-ring structure, which can increase the contact area between the first connecting portion2521and the first position-limiting portion222, thereby increasing the overcurrent area between the case22and the second current collecting member25.

With continued reference toFIG.6, in some embodiments, the second connecting portion2522is of a closed-ring structure that surrounds the edge of the first connecting portion2521.

In some other embodiments, the second connecting portion2522may also be of a non-closed-ring structure, for example, the second connecting portion2522is C-shaped.

The second connecting portion2522is of a closed-ring structure, which can increase the contact area between the second connecting portion2522and the first position-limiting portion222, thereby increasing the overcurrent area between the case22and the second current collecting member25.

As shown inFIGS.12and13,FIG.12is a schematic diagram of a plug-in fit of the first current collecting member24and the second current collecting member25provided in some embodiments of the present application, andFIG.13is a schematic diagram of a plug-in fit of the first current collecting member24and the second current collecting member25provided in some other embodiments of the present application. In some embodiments, the first current collecting member24and the second current collecting member25form a plug-in fit along the thickness direction.

In order to cause the first current collecting member24and the second current collecting member25to form a plug-in fit, one of the first current collecting member24and the second current collecting member25is provided with a groove243, and the other of the first current collecting member24and the second current collecting member25may be provided with a protrusion that is capable of being inserted within the groove243. The groove243and the protrusion form a plug-in positioning fit.

The first current collecting member24and the second current collecting member25form a plug-in fit along the thickness direction X of the end cover, which enables plug-in positioning of the first current collecting member24and the second current collecting member25, thereby enabling improvement of the stability of the relative positional relationship between the first current collecting member24and the second current collecting member25, and facilitating welding of the first current collecting member24and the second current collecting member25and improving the stability of the electrical energy output.

With continued reference toFIGS.12and13, in some embodiments, the first current collecting member24is formed with a groove243on the side facing the end cover23, a part of the second current collecting member25being accommodated in the groove243.

A part of the second current collecting member25being accommodated in the groove243may refer to a part or the whole of the body portion251of the second current collecting member25in the thickness direction X of the end cover being accommodated in the groove243, or it may refer to the whole of the body portion251of the second current collecting member25and a part of the connecting portion252being accommodated in the groove243. The inner diameter of the groove243is consistent with the outer diameter of the body portion251.

In some other embodiments, alternatively, a protrusion that fits into the groove243on the first current collecting member24may be provided separately on the second current collecting member25, with the second current collecting member25itself being disposed outside of the groove243.

In some other embodiments, the groove243may also be provided on the side of the body portion251of the second current collecting member25facing the first current collecting member24, and part or the whole of the second current collecting member25is accommodated within the groove243.

The second current collecting member is plugged into the groove243on the side of the first current collecting member24facing the end cover23, which not only enables plug-in positioning of the first current collecting member24and the second current collecting member25, thereby enabling improvement of the stability of the relative positional relationship between the first current collecting member24and the second current collecting member25, and facilitating welding of the first current collecting member24and the second current collecting member25and improving the stability of the electrical energy output, but also reduces the amount of space occupied by the first current collecting member24and the second current collecting member25in the thickness direction X of the end cover. It also makes the position where the first current collecting member24is provided with the groove243have a smaller thickness, which facilitates the welding of the first current collecting member24to the tabs211.

Referring toFIG.14,FIG.14is a structural schematic diagram of a first current collecting member provided in some embodiments of the present application. In some embodiments, the first current collecting member24is provided with a central hole244penetrating through the first current collecting member24in the thickness direction and the first current collecting member24is formed with a guide groove245on the side facing the electrode assembly21, the guide groove245being configured to guide, towards the outer periphery, electrolyte entering the electrode assembly21through the central hole244.

The guide groove245is in communication with the central hole244and penetrates through the outer edge of the first current collecting member24along a radial direction of the central hole244. The central hole244is arranged coaxially with the battery cell20. In order to facilitate the entry of the electrolyte into the central hole244, the second current collecting member25is also provided with a through hole2513arranged coaxially with the first current collecting member24, the through hole2513being provided in the body portion251of the second current collecting member25.

The guide groove may be arranged on the side of the first current collecting member24facing the electrode assembly21in different forms, such as in a radial arrangement, in a cross shape, or the like.

As shown inFIG.15,FIG.15is a structural schematic diagram of an electrode assembly21provided in some embodiments of the present application. The tab211of the electrode assembly21is kneaded flat to form a recessed portion212. The recessed portion212is used for the flow of electrolyte. The tab211in the region other than the recessed portion212is used for welding to the first current collecting member24, and then a region of the weld mark is formed, which is defined as the first weld mark region213. A region (defined as a second weld mark region246) other than the groove243on the side of the first current collecting member24facing the electrode assembly21is used for welding to the region of the tab211that forms the weld mark. As shown inFIG.16, after welding, the notch of the guide groove245of the first current collecting member24is provided opposite to the notch of the recessed portion212of the tab211, and the guide groove245of the first current collecting member24and the recessed portion212of the tab211together define a space provided for the flow of the electrolyte. In some other embodiments, the kneaded flat tab211may also be provided without the recessed portion212. The welding of the first weld mark region213with the second weld mark region246may be realized by means of laser sweeping, and the depth of the laser sweeping should be less than the sum of the depths of the opposing recessed portion212and guide groove245to ensure a good infiltration of the electrode assembly21in the electrolyte.

In some other embodiments, the kneaded flat tab211may also be provided without the recessed portion212, and when the welding of the tab211with the first current collecting member24is realized by laser sweeping, the depth of the laser sweeping should be less than the depth of the guide groove245, so as to ensure a good infiltration of the electrode assembly21in the electrolyte.

The guide groove245is capable of guiding the electrolyte of the central hole244to a region other than the central hole244, so that the electrolyte is uniformly distributed inside the battery cell20, thereby sufficiently and uniformly infiltrating the electrode assembly21and reducing the possibility of lithium precipitation of the battery cell20.

Referring toFIGS.5and9, in some embodiments, the case22is formed with a first concave portion223recessed inwardly from the outer peripheral wall of the case22, and the case22is formed with a first position-limiting portion222protruding from the inner peripheral wall of the case22at a position corresponding to the first concave portion223, the first concave portion223and the first position-limiting portion222both being of annular structures.

Referring toFIGS.5and9, the first position-limiting portion222includes a first connecting segment2221, a second connecting segment2222, and a third connecting segment2223connected in sequence, where the end of the first connecting segment2221that faces away from the second connecting segment2222is connected to the case22, and the end of the third connecting segment2223that faces away from the second connecting segment2222is connected to the case22. The first connecting segment2221and the third connecting segment2223are arranged opposite to each other along the thickness direction X of the end cover. The first connecting segment2221is provided close to the electrode assembly21relative to the third connecting segment2223. The outer surface of the first connecting segment2221, the outer surface of the second connecting segment2222, and the outer surface of the third connecting segment2223together define the first concave portion223. Among them, the outer surface of the first connecting segment2221, the outer surface of the second connecting segment2222, and the outer surface of the third connecting segment2223all refer to exposed surfaces of the first connecting segment2221, the second connecting segment2222, and the third connecting segment2223.

In some embodiments, there is a circular arc as a transition between the first connecting segment2221and the second connecting segment2222, and there is a circular arc as a transition between the second connecting segment2222and the third connecting segment2223, thus avoiding scratching of the structure inside the case22due to the formation of edges at the connecting position between the first connecting segment2221and the second connecting segment2222and the connecting position between the second connecting segment2222and the third connecting segment2223.

In some other embodiments, the first position-limiting portion222may also be a protrusion provided on the inner circumferential face of the case22.

Forming the first position-limiting portion222in the inner wall of the case22has a large machining difficulty, while the difficulty of forming the first concave portion223in the outer peripheral wall of the case22is lower compared to the difficulty of forming the first position-limiting portion222directly in the inner peripheral wall of the case22; therefore, the difficulty of molding the first position-limiting portion222is lowered by forming the first position-limiting portion222protruding from the inner peripheral wall of the case22at the position of the case22that corresponds to the first concave portion223.

With continued reference toFIGS.5and9, in some embodiments, the case22has a second position-limiting portion224; and in the thickness direction X of the end cover, the second position-limiting portion224and the first position-limiting portion222are used for jointly limiting movement of the end cover23relative to the case22in the thickness direction.

The first position-limiting portion222is of an annular structure, and the edge of the end cover23is inserted in the space formed by the first position-limiting portion222and the second position-limiting portion224.

The second position-limiting portion224and the first position-limiting portion222cooperate to jointly limit movement of the end cover23relative to the case22in the thickness direction X of the end cover, so as to maintain a stable connection relationship between the end cover23and the case22.

In some embodiments, the second position-limiting portion224is a flanging structure formed by means of the case22being bent inwardly at a position of the opening221. It can be understood that the second position-limiting portion224is a part of the case22, which can reduce the connecting relationship on the case22and improve the sealing performance and structural strength of the case22. In some other embodiments, the second position-limiting portion224and the case22may also be provided as two structures in a split manner, with the second position-limiting portion224being connected to the opening221end of the case22by means of welding, or the like.

The second position-limiting portion224is a flanging structure formed by means of the case22being bent inwardly at a position of the opening221, so as to enable the second position-limiting portion224to stably position-limit the end cover23on the side of the end cover23facing away from the electrode assembly21. Moreover, the second position-limiting portion224is a part of the case22, which can also reduce the connecting relationship of the case22and thus improve the structural strength of the case22.

With continued reference toFIGS.5and9, in some embodiments, the battery cell20further includes a sealing member27, the sealing member27being used between the first position-limiting portion222and the end cover23and between the second position-limiting portion224and the end cover23.

The sealing member27includes a first sealing portion271, a second sealing portion272and a third sealing portion273connected in sequence, where the first sealing portion271is used between the side of the first position-limiting portion222facing away from the electrode assembly21and the side of the end cover23facing the electrode assembly21, the second sealing portion272is used between an inner circumferential face of the case22and an outer peripheral face of the end cover23, and the third sealing portion273is used between the side of the second position-limiting portion224facing the electrode assembly21and the side of the end cover23facing away from the electrode assembly21.

The sealing performance of the battery cell20is improved by means of the sealing member27being used between the first position-limiting portion222and the end cover23and between the second position-limiting portion224and the end cover23.

Embodiments of the present application further provide a battery100, the battery100including the battery cell20provided in any of the above embodiments.

The battery cell20includes a first current collecting member24and a second current collecting member25, where the first current collecting member24is connected to the tabs211, and the second current collecting member25connects the first current collecting member24and the first position-limiting portion222of the case22. The first region241of the first current collecting member can be welded to the tab211of an outer ring layer, and the second region242of the first current collecting member can be welded to the tab211of an inner ring layer, so that the tabs211of the inner ring layer and the outer ring layer can both be connected to the first current collecting member24, which enables uniform current conduction to be realized, so as to avoid the problem of excessive local overcurrent due to the failure of the tab211of the outer ring layer to be connected to the current collecting member, thereby reducing the risk of severe polarization of the tab211of the outer ring layer in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation due to polarization, thus improving the safety performance of the battery100.

Embodiments of the present application further provide an electrical device, the electrical device including a battery100provided in the above embodiments.

The battery100does not have the problem of local overcurrent due to the failure of the outer ring tab211to be connected to the current collecting member, thereby reducing the risk of severe polarization of the outer ring tab211in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation, thus improving the electrical safety in the electrical device.

As shown inFIG.17, embodiments of the present application provide a manufacturing device2000for a battery cell, the manufacturing device2000for a battery cell including a providing apparatus2100and an assembling apparatus2200, the providing apparatus2100being configured to provide an electrode assembly21, a case22, an end cover23, a first current collecting member24, and a second current collecting member25, where the electrode assembly21has tabs211; the case22has an opening221, the case22serving as a housing for the electrode assembly21, and the case22is provided with a first position-limiting portion222protruding from the inner side face, the first position-limiting portion222being used for limiting movement of the end cover23towards a direction close to the electrode assembly21; and the end cover23is used for covering the opening221; and the assembling apparatus2200is configured to accommodate the electrode assembly21within the case22, to connect the first current collecting member24to the tabs211, to connect the second current collecting member25to the first current collecting member24and the first position-limiting portion222, and to cover the opening221with the end cover23, where the first current collecting member24includes a first region241overlapping with the first position-limiting portion222along a thickness direction X of the end cover and a second region242not overlapping with the first position-limiting portion222along the thickness direction, the first region241and the second region242both being welded to the tabs211.

As shown inFIG.18, embodiments of the present application further provide a manufacturing method for the battery cell20, the manufacturing method including:Operation S100, providing an electrode assembly21, a case22, an end cover23, a first current collecting member24, and a second current collecting member25, where the electrode assembly21has tabs211; and the case22has an opening221, the case22is used for housing the electrode assembly21, the case22is provided with a first position-limiting portion222protruding from the inner side face, the first position-limiting portion222being used for limiting movement of the end cover23towards a direction close to the electrode assembly21;Operation S200, connecting the first current collecting member24to the tabs211;Operation S300, connecting the second current collecting member25to the first current collecting member24;Operation S400, placing the electrode assembly21within the case22and connecting the second current collecting member25to the first position-limiting portion222; andOperation S500, covering the opening221with the end cover23,where the first current collecting member24includes a first region241overlapping with the first position-limiting portion222along a thickness direction X of the end cover and a second region242not overlapping with the first position-limiting portion222along the thickness direction, and the first region241and the second region242both being welded to the tabs211.

Embodiments of the present application provide a cylindrical battery cell20, the cylindrical battery cell20including a case22, an end cover23, an electrode assembly21, a first current collecting member24, and a second current collecting member25, where the electrode assembly21has tabs211.

The case22has an opening221, the case22is used as a housing to accommodate the electrode assembly21, and the case22is formed with a first concave portion223recessed inwardly from the outer peripheral wall of the case22, and the case22is formed with a first position-limiting portion222protruding from the inner peripheral wall of the case22at a position corresponding to the first concave portion223, the first concave portion223and the first position-limiting portion222both being of annular structures, and the first position-limiting portion222being used for limiting movement of the end cover23towards a direction close to the electrode assembly21, and the battery cell20further includes a second position-limiting portion224, the second position-limiting portion224being a flanging structure formed by means of the opening221of the case22being bent inwardly, and the second position-limiting portion224being used for limiting movement of the end cover23in a direction of moving away from the electrode assembly21. The end cover23is used for covering the opening221; the first current collecting member24is disposed on the side of the first position-limiting portion222facing the electrode assembly21along a thickness direction X of the end cover, the first current collecting member24being used for connecting the tabs211. The first current collecting member24includes a first region241overlapping with the first position-limiting portion222along a thickness direction X of the end cover and a second region242not overlapping with the first position-limiting portion222along the thickness direction, and the first region241and the second region242both being welded to the tabs211. The second current collecting member25is disposed on the side of the first current collecting member24facing away from the electrode assembly21along the thickness direction X of the end cover, the second current collecting member25being used for connecting the first current collecting member24and the first position-limiting portion222, thus realizing the electrical connection between the tabs211and the case22.

The tab211of the inner ring layer and the tab211of the outer ring layer of the battery cell20can both be connected to the first current collecting member24, which enables uniform current conduction to be realized, so as to avoid the problem of excessive local overcurrent due to the failure of the tab211of the outer ring layer to be connected to the current collecting member, thereby reducing the risk of severe polarization of the tab211of the outer ring layer in the cyclic charging and discharging process, and thereby reducing the risk of lithium precipitation due to polarization.

The above are only preferred examples of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of protection of the present application.