Battery cells, batteries and power consuming devices

Abstract

An embodiment of the present application provides a battery cell, a battery, and a power consuming device, the battery cell (100) comprising an electrode assembly (4) having an electrode body (41) and a first tab (42) and a second tab (43) having opposite polarities, the first tab (42) and the second tab (43) being drawn out from the electrode body (41), a first output pole electrically connected to the first tab (42) and a second output pole electrically connected to the second tab (43), and a case (10) used to house the electrode assembly (4), provided with a pressure relief member (21), and having the first output pole and the second output pole at one end and the pressure relief member (21) at the other end along a first direction (z).

Description

[Technical field]

[0001] This application relates to the field of battery technology, and more particularly to battery cells, batteries, and power consuming devices. [Background technology]

[0002] Batteries such as lithium-ion batteries are widely used in electric vehicles due to their advantages such as high energy density, high power density, high cycle life, and long storage time.

[0003] However, improving the in-use safety of batteries in electric vehicles remains a constant challenge in the industry. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application aims to improve the safety of batteries during use. [Means for solving the problem]

[0005] According to a first aspect of the present application, there is provided a battery cell, the battery cell comprising: an electrode assembly including an electrode body and a first tab and a second tab having opposite polarities, the first tab and the second tab extending from the electrode body; a first output pole electrically connected to the first tab and a second output pole electrically connected to the second tab; The electrode assembly is used to house the electrode assembly, and is provided with a pressure relief member. The case has a first output pole and a second output pole at one end and a pressure relief member at the other end along a first direction.

[0006] In this embodiment, the first output pole and the second output pole are provided at one end of the case, and the pressure relief member is provided at the other end of the case, so that when thermal runaway occurs inside the battery cell, the active material erupts from the end where the pressure relief member is located, and separates from the first output pole and the second output pole of the battery cell, and thus separates from the bus bar for electrically connecting the multiple battery cells, reducing the impact on the electrical connection of the battery cells when thermal runaway occurs, preventing a large-area short circuit and high-voltage ignition in the battery, preventing thermal runaway and even ignition and explosion of the power battery system, and improving the safety of the power battery system. Next, by providing the pressure relief member and the output pole at both ends of the case, there is a large space for providing the pressure relief member, which can increase the overflow capacity of the output pole, and the pressure relief member can be easily processed and its release pressure can be more accurately controlled, and the welding stress when welding the bus bar can be prevented from affecting the release pressure of the pressure relief member. Furthermore, by providing the first output pole and the second output pole at the same end of the case, it is possible to easily attach and connect the bus bar when electrically connecting multiple battery cells.

[0007] In some embodiments, the case comprises a first end wall, a second end wall, and a side wall between the first end wall and the second end wall, the first end wall having a first through hole, an electrode lead portion of the battery cell attached to the first through hole and insulated from the first end wall, a pressure relief member provided on the second end wall, the electrode lead portion being a first output pole, and the first end wall being a second output pole.

[0008] In this embodiment, the electrode lead-out portion and the first end wall are provided at the same end of the case, and a pressure relief member is provided at the other end of the case. Therefore, when thermal runaway occurs inside the battery cell, the active material ejects from the end where the pressure relief member is located, and becomes detached from the electrode lead-out portion and first end wall of the battery cell, thereby becoming detached from the bus bar that electrically connects multiple battery cells, thereby reducing the impact on the electrical connections of the battery cells in the event of thermal runaway.

[0009] In some embodiments, the case includes a storage compartment and an end cover, the storage compartment having an opening, the end cover is adapted to cover the opening, the storage compartment being formed by a first end wall and a side wall, and the end cover being the second end wall.

[0010] In this embodiment, by providing the pressure relief member on the end cover independent of the storage section, the process difficulty of providing the pressure relief member can be reduced, making it easier to provide the pressure relief member integrally with the end cover; furthermore, during processing, the accuracy of the size of the thin area of ​​the pressure relief member can be more easily controlled, improving the setting accuracy of the release pressure of the pressure relief member; and, if thermal runaway occurs in the battery cell, the pressure relief member can be reliably activated, thereby improving the operational safety of the battery cell.

[0011] In addition, since the first output pole and the second output pole are not provided on the end cover, but are both provided on the first end wall which is integrally provided on the side wall, the pulling force applied to the connection point between the end cover and the side wall by the bus bar is reduced, fatigue at the connection point is prevented, and the impact of the bus bar on the pressure relief member is reduced, and to a certain extent, damage to the pressure relief member during normal use of the battery cell is reduced and premature pressure relief is prevented.

[0012] In some embodiments, the case comprises a housing and an end cover, the housing having an opening, the end cover is adapted to cover the opening, the housing is formed by a second end wall and a side wall, and the end cover is the first end wall.

[0013] In this embodiment, the electrode lead-out portion is provided on the end cover independent of the storage portion, so that the electrode lead-out portion can be easily attached to the end cover.

[0014] In some embodiments, a first tab extends from the electrode body along a direction facing the electrode lead-out in a first direction, and a second tab extends from the electrode body along a direction away from the electrode lead-out in the first direction, the first tab being electrically connected to the electrode lead-out and the second tab being electrically connected to the first end wall.

[0015] In this embodiment, by drawing out the first tab and the second tab from both ends of the electrode body, respectively, the overflow capacity is increased and the reliability of the insulation between the first tab and the second tab can be easily ensured, thereby improving the operating performance of the battery cell.

[0016] In some embodiments, the battery cell further comprises a first current collecting member and a second current collecting member, the first tab being electrically connected to the electrode lead-out portion by the first current collecting member and the second tab being electrically connected to the first end wall by the second current collecting member.

[0017] In this embodiment, the first tab is electrically connected to the electrode lead portion by the first current collecting member, and the second tab is electrically connected to the first end wall by the second current collecting member, which facilitates welding with the tabs and improves the reliability of the electrical connection between the first tab and the electrode lead portion, and the reliability of the electrical connection between the second tab and the first end wall.

[0018] In some embodiments, a second current collecting member is contacted to the side wall to provide electrical communication between the second tab and the first end wall.

[0019] This embodiment reduces the steps by which the second tab transfers electrical energy to the first end wall, which can increase the reliability of electrical energy transfer.

[0020] In some embodiments, the case comprises a housing and an end cover, the housing having an opening, the end cover is used to cover the opening, the second current collecting member is connected to the end cover, and the end cover is electrically connected to the side wall to provide electronic continuity between the second tab and the first end wall.

[0021] This embodiment electrically connects the second tab and the end cover. For example, in the case of electrical connection by welding, the end cover has a flat welding surface, which makes welding easier and improves the welding effect, thereby improving the reliability of the electrical connection between the second tab and the first end cover.

[0022] In some embodiments, the case comprises a housing and an end cover, the housing has an opening, the end cover is used to cover the opening, the second current collecting member is in contact with the side wall, and the end cover is connected to the second current collecting member to achieve electronic conduction between the second tab and the first end wall.

[0023] This embodiment allows the electrical energy transmitted by the second tab to be transmitted to the first end cover via two types of conductive paths, and when there is a temporary connection in one conductive path, the transmission of electrical energy can continue via the other conductive path, thereby improving the reliability of electrical energy transmission.

[0024] In some embodiments, along the first direction, the second current collecting member is located between the pressure relief member and the second tab, and the second current collecting member is provided with a cutout portion, which is used to provide gas communication between a space on one side of the second current collecting member facing the second tab and a space on the other side facing the pressure relief member.

[0025] This embodiment takes into consideration the provision of an electrode lead-out portion and a pressure relief member at both opposing ends of the case, and by providing a cut-out portion in the second current collecting member, if thermal runaway occurs in any area inside the battery cell, high-temperature, high-pressure gas can smoothly pass through the cut-out portion to reach the pressure relief member and be discharged to the outside through the pressure relief member in a timely manner, improving safety in the event of thermal runaway of the battery cell.

[0026] In some embodiments, the recessed portion includes at least one fourth through hole, one of the fourth through holes being disposed at a central position of the second current collecting member.

[0027] Generally, gas in the electrode assembly is discharged to the outside of the electrode assembly through the tab side, and by providing a fourth through hole at the center of the second current collecting member, the gas discharged from each area of ​​the second tab can reach the fourth through hole in a timely manner, thereby smoothly reaching the pressure relief member.

[0028] In some embodiments, a plurality of fourth through holes are provided, and the remaining fourth through holes are distributed around a central fourth through hole.

[0029] This embodiment reasonably increases the exhaust area, and to a certain extent solves the problem of exhaust delay caused by the blockage of the central position of the second current collecting member.

[0030] In certain embodiments, the cutout further comprises a plurality of notches, the notches extending through the second current collecting member along the first direction, the plurality of notches being circumferentially surrounded by the fourth through hole.

[0031] In this embodiment, by providing a plurality of notches based on the fourth through hole, it is possible to assist the exhaust of the fourth through hole, and when thermal runaway occurs in the battery cell, the airflow can reach the pressure relief member through the fourth through hole and the plurality of notches at the same time. In addition, the notches have a long and thin shape, which can reduce the decrease in strength of the second current collecting member while realizing exhaust, and is easy to process.

[0032] In some embodiments, one end of the cutout communicates with the fourth through hole and extends in a direction away from the fourth through hole.

[0033] This embodiment can reliably exhaust air to the area from the center position to the outer periphery of the second current collecting member, and when thermal runaway occurs in the battery cell, the airflow can flow more smoothly and in a timely manner to the pressure relief member.

[0034] In some embodiments, the cutout further comprises a scale, the scale extending through the second current collecting member along the first direction.

[0035] In this embodiment, the fourth through hole is provided with a number of scales, which can assist the exhaust of the fourth through hole, and when thermal runaway occurs in the battery cell, the airflow can reach the pressure relief member through the fourth through hole and the number of scales at the same time. In addition, the scales can minimize the deterioration of the strength of the second current collecting member while realizing the exhaust.

[0036] In some embodiments, a plurality of scales are provided, and one end of the scales is in communication with the fourth through hole and extends in a direction away from the fourth through hole.

[0037] This embodiment can reliably exhaust air to the area from the center position to the outer periphery of the second current collecting member, and when thermal runaway occurs in the battery cell, the airflow can flow more smoothly and in a timely manner to the pressure relief member.

[0038] In some embodiments, the first tab and the second tab are both extended along one end of the electrode body facing the electrode extension in a first direction, the first tab being electrically connected to the electrode extension and the second tab being electrically connected to the first end wall.

[0039] In this embodiment, the first tab and the second tab are pulled out from one end facing the electrode lead-out portion of the electrode body, which makes it easy to realize electrical connection; in addition, the first tab and the second tab only need to occupy space on one side of the electrode body, which allows the height of the battery cell to be reduced, and is advantageous for improving the energy density of the battery cell.

[0040] In some embodiments, the battery cell further includes a first current collecting member and a second current collecting member, the first tab being electrically connected to the electrode lead-out portion via the first current collecting member and the second tab being electrically connected to the first end wall via the second current collecting member.

[0041] The electrode extension portion has a base and a main body portion, the base is located between the first end wall and the first collecting member and is used to restrict movement of the electrode extension portion away from the interior of the case along the first direction, an insulating member is provided between the first end wall and the base, and at least a portion of the main body portion is located within the first through hole.

[0042] In this embodiment, the electrode extension portion is prevented from escaping from the first through hole by the restricting action of the base, thereby improving the reliability of the electrical connection between the electrode extension portion and the first current collector, and the insulating member can also provide insulation between the electrode extension portion and the first end wall.

[0043] In some embodiments, along the first direction, a maximum thickness t1 of the base satisfies 0.6 mm≦t1≦1.2 mm, and / or a maximum thickness t2 of the first current collecting member satisfies 0.3 mm≦t2≦0.7 mm, and / or a maximum thickness t3 of the second current collecting member satisfies 0.3 mm≦t3≦0.7 mm.

[0044] In this embodiment, by setting the base of the electrode lead-out portion, the first current collecting member, and the second current collecting member to appropriate thicknesses, when thermal runaway occurs in the battery cell, gas is ensured to be discharged through the pressure relief member, and gas is prevented from escaping from the side where the electrode lead-out portion and the first end wall are provided, thereby improving the operational safety of the battery cell.

[0045] In some embodiments, 0.8 mm≦t1≦1 mm, and / or 0.4 mm≦t2≦0.6 mm, and / or 0.4 mm≦t3≦0.6 mm.

[0046] In some embodiments, the electrode lead portion further includes a limit protrusion, and both the base and the limit protrusion are connected to and protrude from the outer peripheral wall of the main body portion, and the limit protrusion and the base are respectively located on the outside and inside of the first end wall along the first direction and are used to clamp a portion of the first end wall.

[0047] In this embodiment, by clamping a part of the first end wall between the limit protrusion and the base, the electrode lead portion can be stably and reliably attached to the first end wall.

[0048] In some embodiments, a recess is provided in the main body, the bottom wall of the recess is connected to the first current collecting member to realize electronic conduction between the electrode lead-out portion and the first tab, and the opening of the recess is provided on one side of the main body facing and / or facing away from the inside of the case.

[0049] In this embodiment, by providing a recess in the main body portion, the thickness of the area where the main body portion and the first current collector are electrically connected can be reduced, thereby improving the reliability of the electrical connection between the main body portion and the first current collector.

[0050] In some embodiments, the bottom wall of the recess is laser welded to a side of the first current collecting member facing away from the interior of the case from the body portion of the first current collecting member.

[0051] By providing a recess in this embodiment, the thickness of the welded area between the main body and the first current collector is reduced, and the main body and the first current collector can be easily welded from the outside of the electrode lead-out portion, thereby improving the reliability of the weld. In addition, metal ions caused by the welding do not enter the case, improving the reliability of the battery cell.

[0052] In some embodiments, the case is cylindrical, the pressure relief member is centrally located on the second end wall and is circular, the pressure relief member has a pressure relief area, and a diameter φ1 of the pressure relief area and a diameter φ of the case satisfy 0.35≦φ1 / φ≦0.85.

[0053] In this embodiment, by setting a proportional relationship between the diameter of the pressure relief area of ​​the pressure relief member and the diameter of the case, when thermal runaway occurs in the battery cell, the pressure relief member has a sufficient open area to quickly dissipate heat from the battery cell, preventing damage to the electrode lead-out part or the case and heat leakage. In addition, after ensuring reliable opening of the pressure relief member, the strength of the end of the case where the pressure relief member is provided is increased, preventing the problem of the pressure relief member opening and leaking due to internal air pressure during normal use of the battery cell, resulting in abnormal electrical connection.

[0054] In some embodiments, 15 mm≦φ≦70 mm.

[0055] In some embodiments, the thickness l1 of the first end wall and the thickness l2 of the second end wall satisfy l1≧l2.

[0056] In this embodiment, by making the thickness of the first end wall greater than the thickness of the second end wall, when thermal runaway occurs inside the battery cell, the amount of deformation on the pressure relief member side of the case is greater than the amount of deformation on the side where the electrode lead-out portion and first end wall are located.This ensures that gas caused by thermal runaway is discharged from the pressure relief member on the second end wall, preventing the gas from flowing to the side where the electrode lead-out portion is located and causing large deformation in the first end wall, and preventing the case from breaking during thermal runaway and causing heat leaks.

[0057] In some embodiments, l1≧1.5*l2.

[0058] In some embodiments, the size range of the first end wall thickness l1 is 0.5 mm≦l1≦1 mm and / or the size range of the second end wall thickness l2 is 0.3 mm≦l2≦1 mm.

[0059] In this embodiment, by designing the first end wall and the second end wall to an appropriate thickness, when thermal runaway occurs in the battery cell, the case is prevented from being significantly deformed under the action of the high-pressure gas inside, and the case is prevented from being damaged during thermal runaway, resulting in heat leakage.

[0060] In some embodiments, 0.6 mm≦l1≦0.8 mm, and / or 0.5 mm≦l2≦0.8 mm.

[0061] In some embodiments, the second end wall is notched, with an area of ​​the second end wall bounded by the notch forming a pressure relief member.

[0062] In this embodiment, when thermal runaway occurs in the battery cell, the internal pressure exceeds the preset release pressure of the pressure relief member, and the notch breaks, releasing the pressure relief member and allowing the airflow inside the case to be discharged to the outside through the opening, thereby improving the operational safety of the battery cell.

[0063] In some embodiments, the thickness l1 of the first end wall and the thickness l3 of the second end wall at the location of the notch satisfy the relationship l1≧2*l3.

[0064] In this embodiment, by setting the size relationship between the thickness of the first end wall and the thickness of the second end wall at the location of the notch, a thin portion with lower strength relative to the first end wall is formed at the notch location. When thermal runaway occurs in the battery cell, the internal gas is preferentially deformed in the thin portion to quickly release the pressure relief member. This allows the internal gas to be smoothly discharged. Also, even if thermal runaway occurs on one side close to the electrode lead-out portion, the gas can preferentially flow toward the pressure relief member. This prevents the area where the first end wall is located from being significantly deformed under the action of the high-pressure gas inside, prevents the case from being damaged during thermal runaway and causes heat leakage, and improves safety on the side where the electrode lead-out portion and first end wall of the battery cell are located.

[0065] In some embodiments, l1≧6*l3.

[0066] In some embodiments, the pressure relief member is circular and has a pressure relief area, and a diameter φ2 of the first through hole and a diameter φ1 of the pressure relief area satisfy the relationship φ2≦φ1.

[0067] In this embodiment, by making the diameter of the first through hole for attaching the electrode lead portion equal to or smaller than the diameter φ of the pressure relief area, the strength of the first end wall where the electrode lead portion of the case is located can be strengthened, and when thermal runaway occurs in the battery cell, gas can flow preferentially toward the pressure relief member, preventing the area where the first end wall is located from being significantly deformed under the action of the high-pressure gas inside, preventing the case from being damaged and causing heat leakage during thermal runaway, and improving safety on the side where the electrode lead portion and first end wall of the battery cell are located.

[0068] In some embodiments, the size range of the diameter φ2 of the first through hole is 8 mm≦φ2≦25 mm and / or the size range of the diameter φ1 of the pressure relief area is 20 mm≦φ1≦35 mm.

[0069] In this embodiment, by designing the diameters of the first through hole and the pressure relief area to appropriate sizes, the strength of the end of the case where the electrode lead-out portion is provided can be ensured, and when thermal runaway occurs in the battery cell, gas can flow preferentially toward the pressure relief member, preventing the area where the first end wall is located from being significantly deformed under the action of the high-pressure gas inside, preventing the case from being damaged in the event of thermal runaway and causing heat leakage, and improving safety on the side where the electrode lead-out portion and first end wall of the battery cell are located.

[0070] In some embodiments, the electrode assembly is formed by winding first and second electrode sheets having opposite polarities and a partition member around a winding axis, the winding axis coinciding with a first direction, and the first and second electrode sheets having first and second tabs, respectively.

[0071] A second through hole extending along the first direction is provided at the center of the electrode assembly, the pressure relief member is circular and has a pressure relief area, and the maximum diameter φ3 of the second through hole and the diameter φ1 of the pressure relief area satisfy the relationship φ3≧0.12*φ1.

[0072] In this embodiment, by making the diameter of the second through hole and the diameter of the pressure relief area satisfy the above relationship, when thermal runaway occurs in the battery cell, the second through hole has a sufficient passage size to allow the high-pressure gas inside to flow quickly to the pressure relief member, allowing the pressure relief member to be released smoothly, making it difficult for heat to accumulate inside the battery cell and dissipate, and preventing the case from deforming significantly and causing heat leakage, thereby improving the operational safety of the battery cell.

[0073] In certain embodiments, the case includes a second end wall and the pressure relief member is located in a central region of the second end wall.

[0074] In this embodiment, by providing the pressure relief member in the central region of the end cover, when thermal runaway occurs in the battery cell, regardless of the direction from which the internal high-temperature, high-pressure airflow reaches the pressure relief member, it has a short airflow path, allowing the pressure relief member to be opened in a timely manner, improving the reliability and safety of the battery cell operation.

[0075] According to a second aspect of the present application, there is provided a battery including the battery cell of the above embodiment.

[0076] In some embodiments, the case has a first end wall, a first through hole is provided in the first end wall, an electrode lead portion of the battery cell is attached to the first through hole and is provided insulated from the first end wall, the electrode lead portion is a first output pole, and the first end wall is a second output pole.

[0077] The battery further includes a bus bar, and a plurality of battery cells are provided, with one end of the bus bar electrically connected to the electrode lead-out portion of one of the battery cells and the other end of the bus bar electrically connected to a first end wall of the other battery cell.

[0078] In this embodiment, when realizing a series, parallel or mixed connection of multiple battery cells inside a battery, with the electrode lead portion as the first output pole of the battery cell and the first end wall as the second output pole of the battery cell, both ends of the bus bar can be directly connected to the electrode lead portion and the first end wall, respectively. Since only one electrode lead portion is provided on the first end wall of the case, this is advantageous for increasing the conductive area of ​​the electrode lead portion. In addition, it is relatively easy to electrically connect to the first end wall by welding or fastener connection, which reduces the difficulty of electrically connecting multiple battery cells, improves the reliability of the electrical connection, and ensures the operating performance and reliability of the battery.

[0079] In some embodiments, the case has a first end wall, a first through hole is provided in the first end wall, an electrode lead portion of the battery cell is attached to the first through hole and is provided insulated from the first end wall, the electrode lead portion is a first output pole, and the first end wall is a second output pole.

[0080] The battery further includes a plurality of bus bars, and in the same battery cell, the electrode lead portion is electrically connected to one of the bus bars and the first end wall is electrically connected to the other of the bus bars.

[0081] In this embodiment, each battery cell can be electrically connected to the other two battery cells by two independent bus bars, and any surrounding area located at the electrode lead-out portion of the first end wall can be used to connect the bus bars, making it possible to adapt to different distribution methods of multiple battery cells.

[0082] In some embodiments, the battery further comprises a support plate and a housing assembly, the battery cells are mounted in the housing assembly by the support plate, the support plate is provided with a third through hole for the flow of exhaust escaping from the pressure relief member, the pressure relief member is circular and has a pressure relief area, and a minimum distance D between the pressure relief member and an inner wall of the housing assembly and a diameter φ1 of the pressure relief area satisfy the relationship 0.4*φ1≦D≦1.2*φ1.

[0083] In this embodiment, by setting an appropriate distance between the pressure relief member and the inner wall of the housing assembly, when thermal runaway occurs in the battery cell, the internal gas and active material can be effectively ejected to quickly cool the battery. In addition, the height of the battery cell can be increased as much as possible while satisfying the safety requirements for thermal runaway, thereby increasing the energy density of the battery cell and enabling the battery to provide greater power.

[0084] According to a third aspect of the present application there is provided a power consuming device comprising a battery according to any of the above embodiments for providing electrical energy to the power consuming device.

[0085] In some embodiments, the power consumption device comprises a vehicle, the battery is disposed between a cockpit and a vehicle floor, the first output pole and the second output pole are both disposed toward the cockpit, and the pressure relief member is disposed toward the vehicle floor.

[0086] In this embodiment, if thermal runaway occurs during use of the battery, the pressure relief member of the battery cell is provided toward the vehicle floor, i.e., facing downward, so that when the pressure relief member is opened, the waste material discharged from the battery is ejected below the vehicle, reducing the impact of high temperature and pressure on the cockpit and occupants and improving safety during use of the vehicle. [Brief description of the drawings]

[0087] In order to more clearly describe the technical solutions of the embodiments of the present application, the following briefly describes the drawings that need to be used in the embodiments. It is obvious, the drawings described below are only some embodiments of the present application, and those skilled in the art can further obtain other drawings based on these drawings without any creative work. [Figure 1] 1A to 1C are schematic diagrams showing the structure of some embodiments of the battery according to the present application for mounting on a vehicle. [Diagram 2] 1 is an exploded view of some embodiments of the battery of the present application. [Diagram 3] 1A to 1C are structural schematic diagrams of some embodiments of a battery cell in the present application. [Figure 4] 1 is an exploded view of some embodiments of a battery cell according to the present application. [Diagram 5] 1A-1C are cross-sectional views of some embodiments of battery cells according to the present application. [Figure 6] 1A to 1C are structural schematic diagrams of several embodiments of an electrode assembly. [Figure 7] 1A-1D are schematic end views of several example electrode assemblies. [Figure 8A] 5A to 5C are schematic diagrams showing the structure of a second current collecting member according to a different embodiment; [Figure 8B] 5A to 5C are schematic diagrams showing the structure of a second current collecting member according to a different embodiment; [Figure 8C] 5A to 5C are schematic diagrams showing the structure of a second current collecting member according to a different embodiment; [Figure 8D] 5A to 5C are schematic diagrams showing the structure of a second current collecting member according to a different embodiment; [Figure 8E] 5A to 5C are schematic diagrams showing the structure of a second current collecting member according to a different embodiment; [Figure 9] FIG. 2 is a schematic diagram showing the size of some embodiments of a battery cell in the present application. [Figure 10] FIG. 10 is an enlarged view of part A in FIG. [Figure 11] FIG. 2 is a structural schematic diagram for electrically connecting two battery cells. [Figure 12] 1 is a structural schematic diagram of a battery cell in a battery according to the present application being attached to a housing assembly by a support plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0088] The embodiments of the present application will be described in more detail below in combination with the drawings and examples. The detailed description of the following examples and the drawings are for illustrative purposes only and are not intended to limit the scope of the present application, i.e. the present application is not limited to the described examples.

[0089] In describing the embodiments of the present application, the term "multiple" means two or more (including two); similarly, "multiple sets" means two or more sets (including two sets); and "multiple sheets" means two or more sheets (including two sheets).

[0090] It is understood that the present application uses terms indicating directions and positional relationships, such as "upper", "lower", "top", "bottom", "front", "rear", "inside" and "outside", which are merely for the purpose of facilitating the description of the present application, and do not indicate or imply that the referred device must have a particular orientation or be configured and operated in a particular orientation, and cannot be considered as limiting the scope of protection of the present application.

[0091] In addition, the terms "first", "second", and "third" are merely for the purpose of explaining the purpose, and cannot be considered as indicating or implying relative importance. "Vertical" is not perpendicular in the strict sense, but within the allowable margin of error. "Parallel" is not parallel in the strict sense, but within the allowable margin of error. All directional terms appearing in the following description are directions shown in the drawings, and do not limit the specific structure of the present application.

[0092] In the description of the present application, further, unless otherwise clearly specified and limited, the terms "attached", "connected to each other", "connected" and the like should be understood in a broad sense, for example, to mean fixedly attached, detachably connected or integrally connected, directly connected to each other, or connected to each other via an intermediate medium. Those skilled in the art can understand the specific concepts of the above technical terms in the present application according to the specific circumstances.

[0093] In this specification, the reference to an "embodiment" means that a particular feature, structure, or characteristic described in combination with the embodiment can be included in at least one embodiment of the present application. The appearance of the word in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will understand, both explicitly and implicitly, that the embodiments described herein can be combined with other embodiments.

[0094] The battery cells may include, but are not limited to, lithium ion secondary batteries, lithium ion primary batteries, lithium sulfur batteries, sodium lithium ion batteries, sodium ion batteries, or magnesium ion batteries. The battery cells may have a cylindrical, flat, rectangular, or other shape, but are not limited to, the embodiments of the present application. Battery cells are generally classified into three types based on the packaging method: prismatic battery cells, rectangular battery cells, and soft-pack battery cells, but are not limited to, the embodiments of the present application.

[0095] A conventional battery cell usually includes a case and an electrode assembly housed in the case, and the case is filled with an electrolyte. The electrode assembly is mainly formed by stacking or rolling a first electrode sheet and a second electrode sheet having opposite polarity, and usually a separator is provided between the first electrode sheet and the second electrode sheet. The coated parts of the first electrode sheet and the second electrode sheet constitute the main body of the electrode assembly, and the uncoated parts of the first electrode sheet and the second electrode sheet constitute the first tab and the second tab, respectively. In the lithium-ion battery, the first electrode sheet may be a positive electrode sheet, comprising a positive electrode coating layer provided on both sides of the positive electrode current collector and the positive electrode current collector, the material of the positive electrode current collector may be, for example, aluminum, and the positive electrode coating may be, for example, lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc., and the second electrode sheet may be a negative electrode sheet, comprising a negative electrode coating layer provided on both sides of the negative electrode current collector and the negative electrode current collector, the material of the negative electrode current collector may be, for example, copper, and the negative electrode coating may be, for example, graphite or silicon, etc. The first tab and the second tab may both be located at one end of the body part or at both ends of the body part, respectively. During charging and discharging of the battery cell, the positive electrode coating and the negative electrode coating react with the electrolyte, and the tabs are connected to the electrode lead-out part to form a current circuit.

[0096] The pressure relief member refers to an element or member that operates to release the internal pressure or temperature when the internal pressure or temperature of the battery cell reaches a certain threshold. The design of the threshold varies according to design needs. The threshold may be determined by one or more materials among the positive electrode sheet, the negative electrode sheet, the electrolyte, and the separator in the battery cell. The pressure relief member may take the form of, for example, an explosion-proof valve, an air valve, a pressure relief valve, or a safety valve, and may specifically take the form of a pressure-sensitive or temperature-sensitive element or structure, that is, when the internal pressure or temperature of the battery cell reaches a certain threshold, the pressure relief member performs an operation, or a thin structure provided on the pressure relief member is broken, thereby forming an opening or passage for releasing the internal pressure or temperature.

[0097] As used herein, "activation" means that the pressure relief member operates or is activated to a certain state, thereby relieving the internal pressure and temperature of the battery cell. The activation of the pressure relief member includes, but is not limited to, at least a portion of the pressure relief member rupturing, crushing, tearing, or opening. When the pressure relief member is activated, the internal waste of the battery cell is discharged from the activated portion. In this manner, the pressure and temperature in the battery cell can be relieved in a controlled manner, thereby avoiding the occurrence of a potentially more serious accident.

[0098] The waste materials from battery cells referred to herein include, but are not limited to, electrolyte, dissolved or split positive and negative electrode sheets, separator fragments, high temperature and pressure gases from reactions (e.g., flammable gases such as CH4, CO, etc.), flames, etc.

[0099] Traditional batteries have the problem of poor safety during use, and research has shown that the safety of vehicle power batteries is the most important performance requirement, and in order to meet the higher driving range, the energy density of the battery cells is becoming higher and higher, and the higher energy density increases the instability of the internal chemical materials, which reduces the thermal runaway boundary of the battery cells accordingly. Therefore, the key to ensuring the safety of the entire power battery system and the vehicle is to prevent the thermal spread after the battery cells experience thermal runaway.

[0100] In conventional cylindrical batteries, in order to simplify the battery cell structure, both the positive output pole and the negative output pole are located at the same end as the pressure relief member, and after the battery cell experiences thermal runaway, the material discharged from the pressure relief member will spurt out into the area where the busbar is located, and the busbar is used to connect the positive output pole and the negative output pole of two battery cells to realize the connection of multiple battery cells. Because the battery pack contains a large number of battery cells connected in series and parallel, the voltage is usually more than 100V, which may cause a large-area short circuit or high-voltage ignition, which may cause the entire power battery system to ignite and explode, resulting in vehicle damage, burning, and even personal injury.

[0101] In response to the above deficiencies, the inventors came up with the idea of ​​positioning the pressure relief member as far away as possible from the positive output electrode and the negative output electrode in order to reduce the impact of high-temperature, high-pressure exhaust on the busbar after thermal runaway occurs in the battery cell and to prevent thermal runaway of the entire power battery system.

[0102] Based on this improvement concept, the present application provides an improved battery cell, the battery cell comprising a case and an electrode assembly, the case being provided with an electrode lead and a pressure relief member, the electrode lead and the pressure relief member being respectively provided at opposite ends of the case along a first direction, the electrode assembly being provided within the case and comprising an electrode body and a first tab and a second tab having opposite polarities, the first tab and the second tab being led out from the electrode body, and at least one of the first tab and the second tab being electrically connected to the electrode lead.

[0103] The battery cell of the embodiment of the present application is applicable to batteries and power consuming devices that use batteries.

[0104] Examples of power consuming devices include mobile phones, portable devices, notebook computers, battery cars, electric cars, steamships, spacecraft, electric toys, electric tools, etc. For example, examples of spacecraft include airplanes, rockets, space shuttles, spaceships, etc., and examples of electric toys include stationary or mobile electric toys such as game consoles, electric car toys, electric steamship toys, and electric airplane toys, and examples of electric tools include electric drills, electric sand turbines, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, metal cutting electric tools such as electric planes, polishing electric tools, assembly electric tools, and railway electric tools.

[0105] As shown in Fig. 1, the power consumption device may be a vehicle 300, for example, a new energy vehicle, which may be a pure electric vehicle, a hybrid vehicle, or a range-extended vehicle, etc., or the power consumption device may be a drone, a steamship, etc. The vehicle 300 may include a cockpit 301 and a vehicle floor 302, and the battery 200 is disposed between the cockpit 301 and the vehicle floor 302. The battery 200 is disposed at the bottom, head, or tail of the vehicle 300, and is used to provide electrical energy for the operation of the motor and other components in the vehicle.

[0106] As shown in FIG. 2 , the battery 200 includes a battery cell 100. The battery 200 may include one or more battery cells 100. When the battery cell 100 is multiple, the multiple battery cells 100 may be connected in series, in parallel, or in a mixed manner. The mixed connection means that the multiple battery cells 100 have both series and parallel connections, and the multiple battery cells 100 are first connected in series, in parallel, or in a mixed manner to form a battery module, and the multiple battery modules are further connected in series, in parallel, or in a mixed manner to form a whole, which is housed in a housing assembly 201. All the battery cells 100 are directly connected in series, in parallel, or in a mixed manner, and the whole consisting of all the battery cells 100 is housed in a housing assembly 201.

[0107] 2 further includes a housing assembly 201, the inside of which is hollow and used to house one or more battery cells 100, and the housing assembly 201 may have different shapes and sizes according to the shape, number, combination manner and other requirements of the housed battery cells 100. For example, the housing assembly 201 may include a housing part 201A, a first cover 201B and a second cover 201C, both of which have openings at opposite ends of the housing part 201A, and the first cover 201B and the second cover 201C are respectively used to close the openings at both ends of the housing part 201A, and for example, according to the arrangement manner of the multiple battery cells 100, the housing part 201A has a rectangular cylindrical structure. In order to facilitate the maintenance of the battery 200, the housing assembly 201 is removably attached to the power consumption device.

[0108] For example, the battery cell 100 may have a cylindrical shape with its axis aligned along a first direction z, and a plurality of battery cells 100 may be arranged in an xoy plane perpendicular to the first direction z, and the plurality of battery cells 100 may be distributed in a rectangular array along a second direction y and a third direction x, where the second direction y is perpendicular to the third direction x.

[0109] Optionally, a structural member of the power consuming device forms a space for housing the battery cell 100, and its function corresponds to the housing assembly 201 in the battery 200; for example, when the battery cell 100 is used in a vehicle 300, the vehicle frame forms a space for housing the battery cell 100.

[0110] The battery cell 100 may be, for example, a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, or a magnesium ion battery.

[0111] This application provides a battery cell 100, and the following embodiments will be described taking the cylindrical battery cell 100 as an example. Figure 3 is a schematic view of the battery cell 100, Figure 4 is an exploded view of the battery cell 100, and Figure 5 is a cross-sectional view of the battery cell 100.

[0112] In the above-mentioned improved battery cell 100, the electrode lead-out portion is defined as an output pole having at least a portion protruding into the outer wall of the case 10, and in order to focus on an embodiment in which the battery cell 100 outputs electrical energy through the electrode lead-out portion and the case, for convenience of explanation, the two poles that output electrical energy are defined as a first output pole and a second output pole, respectively.

[0113] In some embodiments, the battery cell 100 comprises a case 10, an electrode assembly 4, a first output pole and a second output pole, the electrode assembly 4 comprises an electrode body 41 and a first tab 42 and a second tab 43 having opposite polarity, the first tab 42 and the second tab 43 are pulled out from the electrode body 41, the first output pole is electrically connected to the first tab 42, and the second output pole is electrically connected to the second tab 43, the case 10 is used to house the electrode assembly 4, and a pressure relief member 21 is provided in the case 10, and along a first direction z, the first output pole and the second output pole are provided at a first end of the case, and the pressure relief member 21 is provided at the other end of the case 10.

[0114] The case 10 may be a thin-walled hollow structure for housing the electrode assembly 4. The case 10 may be a cylindrical body, a flat body, a rectangular parallelepiped, or other shape.

[0115] The first output pole and the second output pole are used for inputting or outputting electrical energy, and the first tab 42 and the first output pole, and the second tab 43 and the second output pole can be electrically connected by welding, elastic contact, or other methods, and the tabs can be directly connected to the output poles or connected by current collecting members.

[0116] The above describes the specific structure of the pressure relief member 21. Taking the cylindrical battery cell 100 as an example, the first direction z coincides with the central axis direction of the battery cell 100, and the first output pole, the second output pole and the pressure relief member 21 are respectively provided on both ends of the case 10 that face each other along the first direction z.

[0117] The electrode assembly 4 is provided in the case 10, and as shown in Figures 6 and 7, the electrode assembly 4 has a first electrode sheet 45 and a second electrode sheet 46 having opposite polarities wound around a winding axis K to form a wound structure, the winding axis K coinciding with the first direction z, and typically a partition member 47, for example a separator, is provided between the first electrode sheet 45 and the second electrode sheet 46. For a cylindrical battery cell 100, the electrode assembly 4 after winding may be cylindrical, and for a rectangular battery cell 100, the electrode assembly 4 after winding may be flat.

[0118] The first electrode sheet 45 includes a first current collector, the first current collector includes a first body portion and a first tab 42, and the first tab 42 protrudes outward from the first body portion along an end surface in the winding direction K. A first coating layer 45' is provided on the side surface of the first body portion, and the first coating layer 45' may be provided on both sides of the first body portion, or the first coating layer 45' may be provided only on one side of the first body portion with respect to the innermost or outermost electrode sheet. The first tab 42 may extend continuously along the longitudinal direction of the first electrode sheet 45 to form a continuous tab, or the continuous tab may be die-cut to form a sawtooth tab. For example, the first electrode sheet 45 is a positive electrode sheet, the first current collector may be aluminum, and the first coating layer 45' may include a first active material layer, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate.

[0119] The second electrode sheet 46 includes a second current collector, the second current collector includes a second body portion and a second tab 43, and the second tab 43 protrudes outward from the second body portion along the end surface in the winding direction K. A second coating layer 46' is provided on the side of the second body portion, and the second coating layer 46' can be provided on both sides of the second body portion, or the second coating layer 46' can be provided only on one side of the second body portion with respect to the innermost or outermost electrode sheet. The second tab 43 can extend continuously in the longitudinal direction of the second electrode sheet 46 to form a continuous tab, or the continuous tab can be die-cut to form a sawtooth tab. For example, the second electrode sheet 46 is a negative electrode sheet, the second current collector can be copper, and the second coating layer 46' can include a second active material layer, such as graphite or silicon. Alternatively, the first electrode sheet 45 may be a negative electrode sheet and the second electrode sheet 46 may be a positive electrode sheet.

[0120] With respect to the wound electrode assembly 4, the electrode assembly 4 comprises an electrode body 41, a first tab 42 and a second tab 43, the first body portion of the first electrode sheet 45 and the second body portion of the second electrode sheet 46 form the electrode body 41, and the first tab 42 and the second tab 43 are both pulled out from above the electrode body 41. For example, the first tab 42 and the second tab 43 may be pulled out from both ends of the electrode body 41 along the first direction z, or may be pulled out along one end from the electrode body 41 toward the electrode pull-out portion in the first direction z.

[0121] In this embodiment, the first output pole and the second output pole are provided at one end of the case 10, and the pressure relief member 21 is provided at the other end of the case 10. In this way, when thermal runaway occurs inside the battery cell 100, the active material is ejected from the end where the pressure relief member 21 is located, and is far away from the first output pole and the second output pole of the battery cell 100, and thus far away from the bus bar for electrically connecting the multiple battery cells 100. In the event of thermal runaway, this reduces the impact on the electrical connection of the battery cells 100, prevents a large-area short circuit or high-voltage ignition in the battery 200, and prevents thermal runaway and ultimately ignition and explosion of the entire power battery system, thereby improving the operational safety of the power battery system. Next, by providing the pressure relief member 21 and the output pole at both ends of the case 10, there is a large space for providing the pressure relief member 21, the overflow capacity of the output pole can be increased, the pressure relief member 21 can be easily processed, its release pressure can be controlled more accurately, and welding stress can be prevented from affecting the release pressure of the pressure relief member when welding the bus bar. Furthermore, by providing the first output pole and the second output pole at the same end of the case 10, it is possible to easily attach and connect the bus bar when electrically connecting multiple battery cells 100.

[0122] In some embodiments, as shown in FIG. 5 , the case 10 has a first end wall 13, a second end wall 14, and a side wall 15 located between the first end wall 13 and the second end wall 14, which are arranged opposite each other along a first direction z, a first through hole 12 is provided in the first end wall 13, an electrode lead portion 3 of the battery cell 10 is attached to the first through hole 12 and is provided insulated from the first end wall 13, a pressure relief member 21 is provided on the second end wall 14, the electrode lead portion 3 is a first output pole, and the first end wall 13 is a second output pole.

[0123] For example, the case 10 is cylindrical, the side wall 15 is cylindrical with both ends open, and the first end wall 13 and the second end wall 14 are both ends of the cylinder and are used to close both ends of the side wall 15. The electrode lead portion 3 is provided insulated from the first end wall 13; for example, an insulating member is provided between the electrode lead portion 3 and the first end wall 13, or an insulating rubber or the like is applied as a coating.

[0124] The electrode lead-out portion 3 is an output pole protruding from the case 10, and may be, for example, an electrode terminal, etc., to realize electrical connection between different battery cells 100 via a bus bar. The electrode terminal may be designed as a pole, and the pole may have a cylindrical shape, a rectangular pole structure, or a pole structure of other shapes.

[0125] Alternatively, the electrode lead portion 3 is a positive output pole and the first end wall 13 is a negative output pole, in which case the material of the first tab 42 and the first current collecting member 5 is aluminum, and the electrode lead portion 3 may accordingly adopt an aluminum material, and there is no need to provide an electrode lead portion made of a composite material. Alternatively, the electrode lead portion 3 is a negative output pole and the first end wall 13 is a positive output pole.

[0126] Optionally, the polarity of the first end wall 13 is the same as that of the electrode sheet located at the outermost layer among the first electrode sheet 45 and the second electrode sheet 46. When the side wall 15 is connected to the first end wall 13 and has the same polarity, and when metal particles are present between the electrode assembly 4 and the side wall 15, the particles penetrate the outermost partition member 47 of the electrode assembly 4, and then conduct electricity between the outermost electrode sheet and the side wall 15 after penetrating the partition member 47. When the polarity of the outermost electrode sheet and the polarity of the side wall 15 are the same, a short circuit of the battery cell 100 can be avoided, and the safety performance of the battery 200 can be improved.

[0127] In this embodiment, the electrode lead-out portion 3 and the first end wall 13 are provided at the same end of the case 10, and the pressure relief member 21 is provided at the other end of the case 10.Therefore, when thermal runaway occurs inside the battery cell 100, the active material is ejected from the end where the pressure relief member 21 is located, far away from the electrode lead-out portion 3 and first end wall 13 of the battery cell 100, and thereby far away from the bus bar for electrically connecting the multiple battery cells 100, thereby reducing the impact on the electrical connections of the battery cells 100 when thermal runaway occurs.

[0128] In addition, by configuring the electrode lead portion 3 as the first output pole of the battery cell 100 and the first end wall 13 as the second output pole of the battery cell 100, one electrode lead portion can be omitted, solving the problem that the end area of ​​the battery cell 100 is small and layout is difficult, and simplifying the structure of the battery cell 100.

[0129] In some embodiments, as shown in FIG. 5 , the case 10 comprises a storage section 1 and an end cover 2, the storage section 1 has an opening 11, the end cover 2 is used to cover the opening 11, the storage section 1 is formed by a first end wall 13 and a side wall 15, and the end cover 2 is a second end wall 14.

[0130] The end cover 2 and the storage section 1 are independent components, and the end cover 2 can be made of a metal material such as steel or an alloy material. After the installation of the electrode assembly 4 is completed, the end cover 2 can be fixed to the storage section 1 by welding, adhesive or fasteners, and the end cover 2 and the storage section 1 must be connected hermetically to prevent gas leakage.

[0131] The first end wall 13 and the side wall 15 can be formed by integral molding, which is easy to process, and when thermal runaway occurs inside the battery cell 100 and pressure increases, the connection point between the first end wall 13 and the side wall 15 has a strong pressure-resistant ability, and pressure relief by the force relief member 21 takes priority, preventing rupture at the connection point between the first end wall 13 and the side wall 15 and improving the reliability of pressure relief. Optionally, the first end wall 13 and the side wall 15 are connected together by welding.

[0132] For example, for a cylindrical battery cell 100, the storage section 1 may be a cylindrical structure having an opening 11 at one end, and the end cover 2 may be a disk-shaped structure for covering the opening 11, with the end of the storage section 1 remote from the opening 11 being closed.

[0133] For example, the pressure relief member 21 is integrally formed with the end cover 2, i.e., a thinned portion is provided in the end cover 2, and the area surrounded by the thinned portion constitutes the pressure relief member 21. For example, the thinned portion may be a notch 22 that can be provided in the inner wall and / or outer wall of the end cover 2. After the pressure relief member 21 opens, it is broken at the thinned portion to form an opening or passage for releasing the internal pressure or temperature.

[0134] A first through hole 12 can be provided at one end of the storage section 1 far from the end cover 2, the electrode lead-out section 3 is attached to the first through hole 12 from the chamber of the storage section 1, an insulating member 7 is provided between the electrode lead-out section 3 and the storage section 1 to realize insulation between the electrode lead-out section 3 and the storage section 1, and the electrode lead-out section 3 is covered by a plate cover 8.

[0135] In this embodiment, by providing the pressure relief member 21 on the end cover 2 independent of the storage section 1, the process difficulty of providing the pressure relief member 21 can be reduced, making it easier to provide the pressure relief member 21 integrally with the end cover 2. In addition, during processing, the accuracy of the size of the thin area of ​​the pressure relief member 21 can be more easily controlled, improving the setting accuracy of the release pressure of the pressure relief member 21. If thermal runaway occurs in the battery cell 100, the pressure relief member 21 can be reliably activated, thereby improving the operational safety of the battery cell 100.

[0136] In addition, since the first and second output poles are not provided on the end cover 12, but are both provided on the first end wall 13 which is integrally provided on the side wall 15, the pulling force applied by the bus bar to the connection point between the end cover 2 and the side wall 15 is reduced, fatigue at the connection point is prevented, and the impact of the bus bar on the pressure relief member 21 is reduced, and to a certain extent, damage to the pressure relief member 21 during normal use of the battery cell 100 is reduced and premature pressure relief is prevented.

[0137] In some embodiments, the case 10 comprises a storage section 1 and an end cover 2, the storage section 1 having an opening 11, the end cover 2 being used to cover the opening 11, the storage section 1 being formed by a second end wall 14 and a side wall 15, and the end cover 2 being the first end wall 13.

[0138] Optionally, the second end wall 14 and the side wall 15 are formed by integral molding, which is easy to process, and a pressure relief member 21 is provided on the second end wall 14, so that the stress at the connection point between the second end wall 14 and the side wall 15 is small, the tensile stress applied to the pressure relief member 21 can be reduced, and the cutting accuracy of the pressure relief member 21 is not affected. When thermal runaway occurs inside the battery cell 100, the pressure relief member 21 can accurately control the release pressure, and the reliability of pressure relief during thermal runaway can be improved. Optionally, the second end wall 14 and the side wall 15 are connected together by welding or the like.

[0139] In this embodiment, the electrode lead portion 3 is provided on the end cover 2 independent of the storage portion 1, so that the electrode lead portion 3 can be easily attached to the end cover 2.

[0140] Optionally, openings 11 are provided at both ends of the storage section 1, and both openings 11 at both ends are covered by end covers 2, and two electrode lead-out sections 3 and two pressure relief members 21 are provided on each end cover 2.

[0141] In some embodiments, as shown in FIG. 5 , the first tab 42 is extended from the electrode body 41 along a direction facing the electrode extension portion 3 in the first direction z, and the second tab 43 is extended from the electrode body 41 along a direction away from the electrode extension portion 3 in the first direction z, with the first tab 42 being electrically connected to the electrode extension portion 3 and the second tab 43 being electrically connected to the first end wall 13.

[0142] The first tab 42 and the second tab 43 are respectively pulled out from the electrode body 41 along both ends in the first direction z, the first tab 42 being close to the electrode pull-out portion 3 and can be directly connected or electrically connected via a current collecting member, and the second tab 43 being farther from the first end wall 13 and can be electrically connected via the side wall 15 of the case 10, and may then be connected via the current collecting member and / or the second end wall 14.

[0143] In this embodiment, by drawing out the first tab 42 and the second tab 43 from both ends of the electrode body 41, respectively, the overflow capacity is increased and the reliability of the insulation between the first tab 42 and the second tab 43 is easily ensured, thereby improving the operating performance of the battery cell 100.

[0144] In some embodiments, the battery cell 100 further includes a first current collecting member 5 and a second current collecting member 6, and the first tab 42 is electrically connected to the electrode lead-out portion 3 via the first current collecting member 5, and the second tab 43 is electrically connected to the first end wall 13 via the second current collecting member 6.

[0145] 5, the first tab 42 can be fixed to the first current collecting member 5 by welding, and after the electrode assembly 4 and the first current collecting member 5 are attached together to the storage section 1, the electrode lead portion 3 and the first current collecting member 5 are welded from the outside of the first end cover 13. Alternatively, the first tab 42 can be directly connected to the electrode lead portion 3.

[0146] Since the second tab 43 is far from the first end wall 13, it can be electrically connected via the side wall 15 of the case 10, and the second tab 43 can be directly connected to the side wall 15, or the second tab 43 can be electrically connected to the side wall 15 via the second current collecting member 6, specific implementation forms will be described later.

[0147] In this embodiment, the first tab 42 is electrically connected to the electrode lead portion 3 via the first current collecting member 5, and the second tab 43 is electrically connected to the first end wall 13 via the second current collecting member 6, making it easy to weld the tabs and improving the reliability of the electrical connection between the first tab 42 and the electrode lead portion 3, and the reliability of the electrical connection between the second tab 43 and the first end wall 13.

[0148] Below, three implementations are described in which the second tab 43 can be electrically connected to the side wall 15 via the second current collecting member 6.

[0149] In the first implementation, the second current collecting member 6 contacts the side wall 15 and provides electronic continuity between the second tab 43 and the first end wall 13 .

[0150] The electrical energy transmitted from the second tab 43 is directly transmitted to the side wall 15 of the housing 1 via the second current collecting member 6, which is either integrally formed with or conductively connected to the first end cover 13, so that the electrical energy can be transmitted to the first end wall 13. The second current collecting member 6 and the side wall 15 can achieve electronic continuity by tight contact, or the second current collecting member 6 and the side wall 15 are welded together.

[0151] This embodiment can reduce the steps of transferring electrical energy from the second tab 43 to the first end wall 13, improving the reliability of the electrical energy transfer.

[0152] In a second implementation, the case 10 comprises a storage section 1 and an end cover 2, the storage section 1 has an opening 11, the end cover 2 is used to cover the opening 11, the second current collecting member 6 is connected to the end cover 2, and the end cover 2 is electrically connected to the side wall 15 to realize electronic conduction between the second tab 43 and the first end wall 13.

[0153] The second current collecting member 6 does not contact the side wall of the storage section 1, and the end cover 2 is connected to the second current collecting member 6, and the electrical energy transmitted from the second tab 43 is transmitted to the end cover 2 via the second current collecting member 6, and the end cover 2 and the side wall 15 can be connected by welding or the like, so that the electrical energy is transmitted from the end cover 2 to the side wall 15 of the storage section 1, and an electrical connection is realized between the second tab 43 and the first end wall 13. The second current collecting member 6 and the end cover 2 can achieve electronic conduction by tight contact, or the second current collecting member 6 and the end cover 2 are welded from one side of the end cover 2 remote from the electrode assembly 4.

[0154] Alternatively, the end cover 2 and the second current collecting member 6 can be connected by welding. When thermal runaway occurs in the battery cell 100, gas can penetrate the second current collecting member 6 and act on the pressure relief member 21, and the end cover 2 and the second current collecting member 6 have a preset distance in the first direction z. In order to realize the welding of the end cover 2 and the second current collecting member 6, as shown in FIG. 5, the end cover 2 has a recessed portion 23 that protrudes toward the electrode assembly 4 as a whole, and the recessed portion 23 abuts against the second current collecting member 6 and is located radially outside the pressure relief member 21, and the recessed portion 23 and the second current collecting member 6 can be welded from the outside of the end cover 2. For example, the recessed portion 23 is provided coaxially on the outside of the pressure relief member 21, or at least one recessed portion 23 is provided along the circumferential direction on the outer periphery of the pressure relief member 21, so as to realize a larger area of ​​welding and improve the reliability of the electrical connection.

[0155] Optionally, the pressure relief member 21 can be recessed inward a preset distance relative to the wall surface at the outermost end of the end cover 2 to prevent the battery cells 100 from exerting excessive force on the pressure relief member 21 when the end cover 2 is placed face down, thereby protecting the pressure relief member 21.

[0156] In this embodiment, the second tab 43 and the end cover 2 are electrically connected. For example, when the electrical connection is made by welding, the end cover 2 has a flat welding surface, which makes welding easier and improves the welding effect, thereby improving the reliability of the electrical connection between the second tab 43 and the first end cover 13.

[0157] In a third implementation, the case 10 comprises a storage section 1 and an end cover 2, the storage section 1 has an opening 11, the end cover 2 is used to cover the opening 11, the second current collecting member 6 is in contact with the side wall 15, and the end cover 2 is connected to the second current collecting member 6 to realize electronic conduction between the second tab 43 and the first end wall 13.

[0158] The second current collecting member 6 is in contact with the side wall 15 of the storage section 1 and is electrically connected to the end cover 2, so that the electrical energy transmitted from the second tab 43 can be simultaneously transmitted to the first end cover 13 via the above two types of conductive paths.

[0159] This embodiment allows the electrical energy transmitted by the second tab 43 to be transmitted to the first end cover 13 through two types of conductive paths, and when there is a temporary connection in one conductive path, the transmission of electrical energy can continue through the other conductive path, thereby improving the reliability of electrical energy transmission.

[0160] In some embodiments, the case 10 includes a second end wall 14 and the pressure relief member 21 is located in a central region of the second end wall 14 .

[0161] A second through hole 44 extending along the first direction z is provided at the center of the electrode assembly 4, and when thermal runaway occurs in the battery cell 100, most of the internal high-temperature, high-pressure airflow can reach the pressure relief member 21 along the second through hole 44, and act effectively on the pressure relief member 21, ensuring that the pressure relief member 21 is opened.

[0162] In this embodiment, by providing the pressure relief member 21 in the central region of the end cover 2, when thermal runaway occurs in the battery cell 100, no matter from which direction the internal high-temperature, high-pressure airflow reaches the pressure relief member 21, a short airflow path is provided and the pressure relief member 21 opens in a timely manner, improving the reliability and safety of the operation of the battery cell 100.

[0163] In some embodiments, as shown in Figures 8A to 8E, along the first direction z, the second current collecting member 6 is located between the pressure relief member 21 and the second tab 43, and the second current collecting member 6 is provided with a cutout portion 6', which is used to provide gas communication between the space on one side facing the second tab 43 of the second current collecting member 6 and the space on the other side facing the pressure relief member 21.

[0164] The installation shape and size of the cutout portion 6' not only satisfy the strength of the second current collecting member 6, but also enable the internal gas to quickly and smoothly reach the pressure relief member 21 when thermal runaway occurs in the battery cell 100. A second through hole 44 extending along the first direction z is provided at the center of the electrode assembly 4. When thermal runaway occurs in the battery cell 100, most of the internal high-temperature and high-pressure airflow flows along the second through hole 44 and can reach the pressure relief member 21 through the cutout portion 6', ensuring that the pressure relief member 21 is opened.

[0165] In this embodiment, the electrode lead-out portion and the pressure relief member 21 are provided at both opposing ends of the case 10, and by providing a cut-out portion 6' in the second current collecting member 6, no matter where inside the battery cell 100 thermal runaway occurs, the high-temperature, high-pressure gas can pass smoothly through the cut-out portion 6' and reach the pressure relief member 21, and can be discharged to the outside via the pressure relief member 21 in a timely manner, improving safety in the event of thermal runaway of the battery cell 100.

[0166] 8A to 8E, in some embodiments, the cutout portion 6′ includes at least one fourth through hole 61, and one of the fourth through holes 61 is provided at the center position of the second current collecting member 6. For example, the fourth through hole 61 may be a round hole, an elliptical hole, a polygonal hole, or the like.

[0167] Generally, gas within the electrode assembly 4 is discharged to the outside of the electrode assembly 4 from the tab side, and by providing a fourth through hole 61 at the center of the second current collecting member 6, all of the gas discharged from each area of ​​the second tab 43 can reach the fourth through hole 61 in a more timely manner, thereby allowing it to reach the pressure relief member 21 smoothly.

[0168] In some embodiments, as shown in Figure 8C, a plurality of fourth through holes 61 are provided, with the other fourth through holes 61 being distributed around a centrally located fourth through hole 61. For example, the other fourth through holes 61 may be uniformly distributed around the centrally located fourth through hole 61, or the other fourth through holes 61 may be distributed in the area where the second tab 43 is provided.

[0169] This embodiment can reasonably increase the exhaust area and solve the problem of exhaust delay caused by the blockage of the center position of the second current collecting member 6 to a certain extent.

[0170] 8B and 8E , the cutout portion 6′ further includes a plurality of notches 63, which penetrate the second current collecting member 6 along the first direction z, and the plurality of notches 63 are surrounded by the periphery of the fourth through hole 61. For example, the notches 63 have an elongated shape with a certain width, and the notches 63 can extend along a straight line, e.g., extending along a radial direction of the circular second current collecting member 6, or the notches 63 extend along a curved line, e.g., extending along a circumferential direction of the circular second current collecting member 6.

[0171] In this embodiment, by providing a plurality of notches 63 above the fourth through hole 61, it is possible to assist exhaust of the fourth through hole 61, and when thermal runaway occurs in the battery cell 100, the airflow can reach the pressure relief member 21 simultaneously through the fourth through hole 61 and the plurality of notches 63. In addition, the notches 63 have a long and thin shape, which can reduce a decrease in the strength of the second current collecting member 6 while realizing exhaust, and is also easy to process.

[0172] In some embodiments, one end of the notch 63 communicates with the fourth through hole 61 and extends in a direction away from the fourth through hole 61 .

[0173] For example, the second current collecting member 6 may be circular, one end of the notch 63 may be connected to the fourth through hole 61, and may extend in a radial direction of the second current collecting member 6 away from the fourth through hole 61, and the plurality of notches 63 may be uniformly distributed in the circumferential direction. Optionally, one end of the notch 63 may not be connected to the fourth through hole 61, but may be spaced a predetermined distance apart.

[0174] In this embodiment, air can be reliably exhausted to the area from the center position of the second current collecting member 6 to the outer periphery, and when thermal runaway occurs in the battery cell 100, the air can flow to the pressure relief member 21 more smoothly and in a timely manner.

[0175] In some embodiments, as shown in Figures 8A and 8D, the cutout 6' further comprises a scale 62, which penetrates the second current collecting member 6 along the first direction z.

[0176] For example, the scale 62 is linear, and theoretically there is no gap between the two side walls forming the scale 62 in the same plane, but in practice there may be a slight gap, and under the action of air pressure, the second current collecting member 6 may deform at the scale 62 to form a gap between the two side walls of the scale 62. The scale 62 may extend continuously, or may extend intermittently to form a broken line. The scale 62 may extend along a straight line, for example extending along the radial direction of the circular second current collecting member 6, or the scale 62 may extend along a curved line, for example extending along the circumferential direction of the circular second current collecting member 6.

[0177] In this embodiment, by providing a plurality of scales 62 above the fourth through-hole 61, it is possible to assist exhaust of the fourth through-hole 61, and when thermal runaway occurs in the battery cell 100, the airflow can reach the pressure relief member 21 simultaneously through the fourth through-hole 61 and the plurality of scales 62. In addition, the scales 62 can minimize the decrease in strength of the second current collecting member 6 while realizing exhaust.

[0178] In some embodiments, a plurality of scales 62 are provided, and one end of the scale 62 is connected to the fourth through-hole 61 and extends in a direction away from the fourth through-hole 61.

[0179] For example, the second current collecting member 6 may be circular, one end of the scale 62 may be connected to the fourth through hole 61, and may extend in a radial direction of the second current collecting member 6 away from the fourth through hole 61, and the multiple scales 62 may be uniformly distributed in the circumferential direction. Optionally, one end of the notch 63 may not be connected to the fourth through hole 61, and may be spaced a predetermined distance apart.

[0180] In this embodiment, air can be reliably exhausted to the area from the center position of the second current collecting member 6 to the outer periphery, and when thermal runaway occurs in the battery cell 100, the air can flow to the pressure relief member 21 more smoothly and in a timely manner.

[0181] Hereinafter, the cutout portions 6' provided in the second current collecting members 6 in Figs. 8A to 8E will be described respectively.

[0182] As shown in FIG. 8A, the cutout portion 6' can have a fourth through hole 61 and a scale 62 provided in the second current collecting member 6. For example, the second current collecting member 6 can be circular, the fourth through hole 61 can be located at the center of the second current collecting member 6, and the scale 62 penetrates the second current collecting member 6, one end of the scale 62 communicates with the fourth through hole 61, and the other end extends outward along the radial direction. For example, the scale 62 can be provided continuously or discontinuously, and a plurality of scales 62 can be provided, radially. For example, four scales 62 can be provided to form a cross shape.

[0183] This embodiment can reliably vent the area from the center position of the second current collecting member 6 to the outer periphery, minimizes the reduction in strength of the second current collecting member 6 due to the provision of the cutout portion 6', and the linear scale 62 is convenient for processing.

[0184] 8B, the cutout portion 6' can include a fourth through hole 61 and a notch 63 provided in the second current collecting member 6, for example, the second current collecting member 6 can be circular, the fourth through hole 61 can be located at the center of the second current collecting member 6, and the notch 63 can penetrate the second current collecting member 6 and extend along the radial direction. A plurality of notches 63 are provided in a radial pattern, for example, four notches 63 can be provided to form a cross shape.

[0185] In this embodiment, exhaust can be reliably performed in the region from the center position of the second current collecting member 6 to the outer periphery, and while achieving exhaustion, the decrease in strength of the second current collecting member 6 is reduced, and linear cutouts 63 can also be easily machined.

[0186] As shown in FIG. 8C , the cutout portion 6′ can have at least one fourth through hole 61 provided in the second current collecting member 6, for example, one fourth through hole 61 can be provided, and for a circular second current collecting member 6, the fourth through hole 61 can be provided at a central position of the second current collecting member 6, or multiple fourth through holes 61 can be provided, for example, one of the fourth through holes 61 is located at the central position of the second current collecting member 6, and the other fourth through holes 61 are distributed around the fourth through hole 61 located at the central position.

[0187] This embodiment can reasonably increase the exhaust area, and to a certain extent solve the problem of exhaust delay caused by the blockage of the center position of the second current collecting member 6, and such a cutout portion 6' is easy to process.

[0188] 8D, the difference from FIG. 8A is that the scale 62 has a curved shape, for example, the scale 62 has an arc shape or a circular shape. The scale 62 can be provided concentrically with the fourth through hole 61. This embodiment can have a good exhaust effect in the circumferential direction of the second current collecting member 6.

[0189] 8E, the difference from FIG. 8B is that the notch 63 is curved, for example, the notch 63 can be arc-shaped or circular, and can be provided concentrically with the fourth through hole 61. For example, the notch 63 can be provided continuously, or the notch 63 can be provided in a plurality of segments, and the plurality of segments of the notch 63 can be provided at intervals on the outer periphery of the fourth through hole 61. This embodiment has a good exhaust effect in the circumferential direction of the second current collecting member 6, and the notch 63 can be easily processed.

[0190] In some embodiments, the first tab 42 and the second tab 43 are both extended along one end of the electrode body 41 facing the electrode extension portion 3 in the first direction z, and the first tab 42 is electrically connected to the electrode extension portion 3 and the second tab 43 is electrically connected to the first end wall 13.

[0191] The first tab 42 and the second tab 43 are pulled out from the electrode body 41 along the same end in the first direction z, and the distance between the first tab 42 and the electrode pull-out portion 3 and the distance between the second tab 43 and the first end wall 13 are both close, and they may be directly connected or electrically connected via a collecting member.

[0192] In this embodiment, the first tab 42 and the second tab 43 are both pulled out from one end of the electrode body 41 facing the electrode pull-out portion 3, making it easier to achieve electrical connection; further, the first tab 42 and the second tab 43 need to occupy space on only one side of the electrode body 41, allowing the height of the battery cell 100 to be reduced, which is advantageous for improving the energy density of the battery cell 100.

[0193] In some embodiments, the battery cell 100 further includes a first current collecting member 5 and a second current collecting member 6, the first tab 42 is electrically connected to the electrode lead portion 3 via the first current collecting member 5, and the second tab 43 is electrically connected to the first end wall 13 via the second current collecting member 6, the electrode lead portion 3 includes a base 31 and a main body portion 32, the base 31 is located between the first end wall 13 and the first current collecting member 5 and is used to restrict movement of the electrode lead portion 3 along a direction away from the inside of the case 10 along the first direction z, an insulating member 7 is provided between the first end wall 13 and the base 31, and at least a portion of the main body portion 32 is located within the first through hole 12.

[0194] The overall size of the outer diameter of the base 31 is larger than the first through hole 12, the base 31 is used to electrically connect to the first current collector 5, and there is a gap between the base 31 and the first end wall 13. At least a portion of the body portion 32 is located within the first through hole 12, and there is a gap between the body portion 32 and the inner wall of the first through hole 12. For example, the electrode lead portion 3 has a stepped cylindrical shape as a whole, the body portion 32 is inserted into the first through hole 12, and the diameter of the body portion 32 is smaller than the inner diameter of the first through hole 12, making it easy to install the insulating member 7.

[0195] The insulating member 7 may be C-shaped, and the side wall portion of the first through hole 12 is fitted into the opening of the C-shaped insulating member 7 so that the insulating member 7 surrounds the inner wall of the first through hole 12 and the area adjacent to the first through hole 12 on the inner and outer surfaces of the first end wall 13. The portion of the insulating member 7 facing the first current collector 5 of the first end wall 13 is attached to the inner surface of the first end wall 13.

[0196] In this embodiment, the electrode extension portion 3 is prevented from escaping from the first through hole 12 by the restricting action of the base 31, thereby improving the reliability of the electrical connection between the electrode extension portion 3 and the first current collector 5, and insulation between the electrode extension portion 3 and the first end wall 13 is achieved by the insulating member 7.

[0197] In some embodiments, as shown in FIG. 9 , the size range of the maximum thickness t1 of the base 31 of the electrode lead portion 3 is 0.6 mm≦t1≦1.2 mm, and / or the size range of the maximum thickness t2 of the first current collecting member 5 is 0.3 mm≦t2≦0.7 mm, and / or the size range of the maximum thickness t3 of the second current collecting member 6 is 0.3 mm≦t3≦0.7 mm.

[0198] In order to achieve a better effect, 0.8 mm≦t1≦1 mm, 0.4 mm≦t2≦0.6 mm, and / or 0.4 mm≦t3≦0.6 mm.

[0199] For example, the maximum thickness t1 of the base 31 may be greater than the maximum thickness t2 of the first current collecting member 5 or the maximum thickness t3 of the second current collecting member 6, thereby preventing airflow from spraying out through the attachment position of the electrode lead-out portion 3 in the event of thermal runaway in the battery cell 100.

[0200] In this embodiment, by setting the base 31 of the electrode lead-out portion 3, the first current collecting member 5, and the second current collecting member 6 to appropriate thicknesses, when thermal runaway occurs in the battery cell 100, gas is discharged through the pressure relief member 21, preventing the gas from escaping from the side where the electrode lead-out portion 3 and the first end wall 13 are provided, thereby improving the operational safety of the battery cell 100.

[0201] In some embodiments, the electrode lead portion 3 further includes a limit protrusion 33, and both the base 31 and the limit protrusion 33 are connected to and protrude from the outer peripheral wall of the main body portion 32, and the limit protrusion 33 and the base 31 are respectively located on the outside and inside of the first end wall 13 along the first direction z, and are used to clamp a portion of the first end wall 13.

[0202] Both the base 31 and the limit protrusion 33 are connected to the outer peripheral wall of the main body 32, and there is also a gap between the limit protrusion 33 and the outer surface of the first end wall 13, which is used to provide an insulating member 7 between the limit protrusion 33 and the first end wall 13. For example, the electrode lead-out portion 3 has a stepped cylindrical shape as a whole, and the diameters of the base 31 and the limit protrusion 33 are both larger than the diameter of the main body 32, the diameter of the limit protrusion 33 is smaller than the diameter of the base 31, and the diameter of the main body 32 is smaller than the inner diameter of the first through-hole 12.

[0203] A groove is formed on the outer wall of the electrode lead portion 3 between the base 31, the main body portion 32 and the limit protrusion 33, the insulating member 7 is C-shaped and can be fitted into the groove, and the opening of the C-shaped insulating member 7 coincides with the direction of the opening of the groove, the side wall portion of the first through hole 12 is fitted into the C-shaped opening of the insulating member 7, the first cantilever of the insulating member 7 is positioned between the first end wall 13 and the base 31, and the first cantilever is provided beyond the base 31, the second cantilever is positioned between the first end wall 13 and the limit protrusion 33, and the second cantilever is provided beyond the limit protrusion 33, and the side wall portion connecting the first cantilever and the second cantilever is positioned between the inner wall of the first through hole 12 and the main body portion 32. The outer ends of the two cantilevers of the insulating member 7 can reliably achieve insulation between the electrode lead portion 3 and the first end wall 13 through such insulating member 7, thereby preventing high-pressure gas from escaping from the gap between the first end wall 13 and the electrode lead portion 3 in the event of thermal runaway.

[0204] In this embodiment, by clamping a part of the first end wall 13 between the limit protrusion 33 and the base 31, the electrode lead portion 3 can be attached to the first end wall 13 more stably and reliably.

[0205] In some embodiments, a recess 34 is provided in the main body 32, and the bottom wall of the recess 34 is connected to the first current collecting member 5 to realize electronic conduction between the electrode lead 3 and the first tab 42, and the opening of the recess 34 is provided on one side of the main body 32 facing and / or facing away from the inside of the case 10.

[0206] 5, the opening of the recess 34 is provided on one side of the main body 32 away from the inside of the case 10, and the bottom wall of the recess 34 is closer to the first current collecting member 5, facilitating the electrical connection between the two, and the first current collecting member 5 is designed to have a flat structure to reduce the difficulty of processing. The recess 34 is stepped and includes a first recess 341 and a second recess 342, the second recess 342 is provided on the bottom wall of the first recess 341, the inner diameter of the second recess 342 is smaller than the inner diameter of the first recess 341, and the bottom wall of the second recess 342 is provided with a third through hole 343, which is used to inject the electrolyte into the case 10, and the plate cover 8 is fitted into the first groove 341 and used to close the opening of the recess 34, so as to close the third through hole 343.

[0207] In this embodiment, by providing a recess 34 in the main body portion 32, the thickness of the electrical connection area between the main body portion 32 and the first current collector 5 can be reduced, and the reliability of the electrical connection between the main body portion 32 and the first current collector 5 can be improved.

[0208] In some embodiments, the bottom wall of the recess 34 and the first current collecting member 5 are laser welded from one side of the body portion 32 facing away from the inside of the case 10 .

[0209] In this embodiment, by providing a recess 34, the thickness of the welding area between the main body portion 32 and the first current collector 5 is reduced, and the main body portion 32 and the first current collector 5 can be easily welded from the outside of the electrode lead-out portion 3, improving the reliability of the welding. In addition, metal ions caused by the welding are prevented from entering the case 10, improving the reliability of the battery cell 100.

[0210] In some embodiments, as shown in FIG. 9, the case 10 is cylindrical, the pressure relief member 21 is disposed at the center of the second end wall 14 and is circular, the pressure relief member 21 has a pressure relief area, and the diameter φ1 of the pressure relief area and the diameter φ of the case 10 satisfy the relationship 0.35≦φ1 / φ≦0.85.

[0211] The pressure relief member 21 is formed by providing a reduced thickness portion, for example, the reduced thickness portion is a notch 22, and the area surrounded by the notch 22 constitutes the pressure relief area, and for ease of measurement, the diameter φ1 of the pressure relief area can be expressed as the diameter of a circle surrounded by the inner wall of the notch 22. In one construction, the pressure relief member 21 is integrally formed with the second end wall 14, i.e., the notch 22 is directly machined into the second end wall 14, and in another construction, the pressure relief member 21 is an independent part, the outer wall of which is connected to the second end wall 14 by welding, and the diameter of the outer wall of the pressure relief member 21 is larger than the maximum diameter of the notch 22, and the diameter of the pressure relief area is still the diameter of a circle surrounded by the inner wall of the notch 22.

[0212] If φ1<0.35*φ, then in the event of thermal runaway occurring in the battery cell 100 close to the electrode lead-out portion 3, the open area of ​​the pressure relief region of the pressure relief member 21 will be insufficient and the rate at which heat is dissipated from the battery cell 100 will be too slow, risking damage to the electrode lead-out portion 3 or case 10 or heat leakage. If φ1>0.85*φ, then the area proportionately occupied by the pressure relief region of the pressure relief member 21 in the second end wall 14 will be large, resulting in the strength of the second end wall 14 being insufficient and the pressure relief member 21 being opened by the gas pressure due to the internal gas during use of the battery cell 100, resulting in electrolyte leakage or abnormal electrical connection.

[0213] The influence of the diameter design of the pressure relief member 21 on the safety of the battery cell 100 is explained below in Table 1, and the unit of the size parameters in the table below is all mm.

[0214] [Table 1]

[0215] In Table 1, for Example 1, φ1 / φ<0.35, and the proportion of the pressure relief area of ​​the pressure relief member 21 to the area of ​​the end of the case 10 is small, and when a needling failure test is performed on the side where the electrode lead-out portion 3 and the first end wall 13 are located, if a short circuit occurs in the battery cell 100 and thermal runaway occurs inside, the thin portion forming the pressure relief member 21 is small, for example the cut is short, making it difficult to open, so that even if the pressure relief member 21 opens, the discharge speed of the high-temperature, high-pressure gas from the pressure relief member 21 is slow, and the gas is discharged toward one side of the electrode lead-out portion due to the instantaneous high pressure, damaging the electrode lead-out portion and causing a failure in the electrical connection of the battery cell 100. However, the area of ​​the pressure relief area of ​​the pressure relief member 21 is small, and the strength of the end cover 2 on which the pressure relief member 21 is provided can be ensured, and there is no leakage phenomenon during use. In each table, the side on which the electrode lead portion 3 and the first end wall 13 are located is abbreviated to "electrical connection side."

[0216] In comparison with Examples 2 to 5, 0.35<φ1 / φ<0.85, and the proportion of the pressure relief area of ​​pressure relief member 21 to the area of ​​the end of case 10 is large, and when a needling failure test is performed near the side where first end wall 13 of electrode lead-out portion 3 is located, if a short circuit occurs in battery cell 100 and thermal runaway occurs inside, the thin portion forming pressure relief member 21 is large, for example the incision is long, making it easier to open, and after pressure relief member 21 is opened, high temperature and high pressure gas can be quickly discharged from pressure relief member 21 and gas is prevented from being discharged from the side toward electrode lead-out portion 3, thereby avoiding damage to electrode lead-out portion 3 and ensuring effective electrical connection of battery cell 100. However, in Example 6, the area of ​​pressure relief member 21 is large, which reduces the strength of end cover 2 on which pressure relief member 21 is provided, causing leakage during use.

[0217] In this embodiment, by setting a proportional relationship between the diameter of the pressure relief area of ​​pressure relief member 21 and the diameter of case 10, when thermal runaway occurs in the battery cell 100, the pressure relief member 21 has a sufficient open area to discharge heat from the battery cell 100, preventing damage to the electrode lead-out part or case 10 and heat leakage. In addition, after ensuring that the pressure relief member 21 is reliably opened, the strength of the end of the case 10 where the pressure relief member 21 is provided is increased, preventing the problem of the pressure relief member 21 opening and leaking due to the internal air pressure during normal use of the battery cell 100, causing abnormal electrical connections.

[0218] In some embodiments, the case 10 is cylindrical and has a diameter φ, where 15 mm≦φ≦70 mm.

[0219] To achieve a good effect, φ can be selected between 30mm and 55mm. If φ<15mm and φ>70mm, the power of the battery 200 will be insufficient. If the diameter of the case 10 is too small, the energy density of the battery cells 100 will be small, and when the battery cells 100 are grouped together, for example, in the case of cylindrical battery cells 100, a large amount of space will be wasted, resulting in a shortage of power of the battery 200. If the diameter of the case 10 is too large, even if the energy density of the battery cells 100 is improved, the remaining space in the battery 200 may not be enough to accommodate an additional row of battery cells 100, and the number of battery cells 100 per row will be large, resulting in a large loss of power of the battery 200.

[0220] Table 2 below explains the effect of the design of h and φ on the total power of the battery 200. In the table below, the units of h and φ are both mm, and the unit of the total power is kWh.

[0221] [Table 2]

[0222] This embodiment can ensure sufficient power for battery 200 to meet the power demand, and can select battery cells 100 with an appropriate diameter according to the internal space of housing assembly 201, thereby maximizing the space utilization rate within housing assembly 201 and reducing internal wasted space, and when the volume of battery 200 is constant, can maximize the total power and improve the energy density of battery 200.

[0223] In some embodiments, as shown in FIG. 9 , the electrode lead portion 3 is provided on a first end wall 13 of the case 10, the pressure relief member 21 is provided on a second end wall 14 of the case 10, and the thickness l1 of the first end wall 13 and the thickness l2 of the second end wall 14 satisfy the relationship l1 ≧ l2.

[0224] The case 10 can include a storage part 1 and an end cover 2. The end cover 2 closes the opening 11 of the storage part 1. The pressure relief member 21 is provided on the end cover 2. The end cover 2 serves as the second end wall 14, and the thickness l2 of the second end wall 14 is the thickness of the end cover 2. This thickness is not the thickness at the location where the notch 22 is provided. The first end wall 13 of the case 10 is the end wall far from the opening 11 of the storage part 1, that is, the end wall where the electrode lead-out part 3 of the storage part 1 is provided. Both the thickness l1 of the first end wall 13 and the thickness l2 of the second end wall 14 are the thicknesses of most regions on the end wall. The first end wall 13 or the second end wall 14 is partially provided with protrusions or concave grooves, which have little influence on the strength of the end wall body. Therefore, for the ease of measurement, the thickness of the end wall is represented by the thickness of the end wall body region.

[0225] To achieve excellent effects, l1 ≧ 1.5 * l2. When l1 < l2, if thermal runaway occurs inside the battery cell 100, the amount of deformation on the side of the pressure relief member 21 of the case 10 is smaller than the amount of deformation on the side where the electrode lead-out part 3 and the first end wall 13 are located, and it is likely to be damaged during thermal runaway and heat leakage occurs.

[0226] In this embodiment, by making the thickness l1 of the first end wall 13 larger than the thickness l2 of the second end wall 14, when thermal runaway occurs inside the battery cell 100, the amount of deformation on the side of the pressure relief member 21 of the case 10 is made larger than the amount of deformation on the side where the electrode lead-out part 3 and the first end wall 13 are located, and the gas due to thermal runaway is surely discharged from the pressure relief member 21 on the second end wall 14, preventing the gas from flowing to the side where the electrode lead-out part 3 is located and causing a large amount of deformation on the first end wall 13, and preventing the case 10 from being damaged during thermal runaway and heat leakage from occurring.

[0227] In some embodiments, the size range of the thickness l1 of the first end wall 13 is 0.5 mm ≦ l1 ≦ 1 mm, and / or the size range of the thickness l2 of the second end wall 14 is 0.3 mm ≦ l2 ≦ 1 mm.

[0228] To achieve excellent effects, 0.6 mm ≦ l1 ≦ 0.8 mm, 0.5 mm ≦ l2 ≦ 0.8 mm.

[0229] In this embodiment, by designing the first end wall 13 and the second end wall 14 to an appropriate thickness, when thermal runaway occurs in the battery cell 100, the case 10 is significantly deformed under the action of the high-pressure gas inside, and the case 10 is prevented from being damaged during thermal runaway, resulting in heat leakage.

[0230] In some embodiments, as shown in FIGS. 9 and 10, second end wall 14 is provided with a notch 22, and the area of ​​second end wall 14 surrounded by notch 22 forms pressure relief member 21.

[0231] The incision 22 can be surrounded by a circle, an ellipse, a polygon, etc., and the extension path of the incision 22 can be closed or open.

[0232] In this embodiment, when thermal runaway occurs in the battery cell 100, the internal pressure exceeds the preset release pressure of the pressure relief member 21, and then the notch 22 bursts to release the pressure relief member 21, and the airflow inside the case 10 is discharged to the outside through the opening, thereby improving the operational safety of the battery cell 100.

[0233] In some embodiments, the thickness l1 of the first end wall 13 and the thickness l3 of the second end wall 14 at the location where the notch 22 is provided satisfy the relationship l1≧2*l3.

[0234] In order to achieve good effect, l1≧6*l3.

[0235] The thickness l3 of the second end wall 14 at the point where the notch 22 is provided is the distance between the deepest point of the notch 22 and the surface of the second end wall 14 furthest from the notch 22.

[0236] In this embodiment, by setting the size relationship between the thickness l1 of the first end wall 13 and the thickness l3 of the second end wall 14 at the location of the notch 22, a thin portion with low strength relative to the first end wall 13 is formed at the location of the notch 22. When thermal runaway occurs in the battery cell 100, the internal gas is preferentially deformed in the thin portion, causing the pressure relief member 21 to be quickly released. This allows the internal gas to be smoothly discharged. Also, even if thermal runaway occurs on one side close to the electrode lead-out portion, the gas can preferentially flow toward the pressure relief member 21. This prevents the area where the first end wall 13 is located from being significantly deformed under the action of the high-pressure gas inside, prevents the case 10 from being damaged in the event of thermal runaway, causing heat leakage, and improves safety on the side of the battery cell 100 where the electrode lead-out portion 3 and first end wall 13 are located.

[0237] In some embodiments, in order to achieve excellent results, the thickness l1 of the first end wall 13 and the thickness l3 of the second end wall 14 at the location where the notch 22 is provided satisfy the relationship l1≧6*l3.

[0238] [Table 3]

[0239] In Table 3, for Examples 3 and 4, l1<6*l3, and when a needling failure test is performed near the side where the electrode lead-out portion 3 and the first end wall 13 are located, if a short circuit occurs in the battery cell 100 and thermal runaway occurs internally, because the first end wall 13 is thin, high-temperature, high-pressure gas will more easily flow in the direction toward the first end wall 13, causing the first end wall 13 to deform or break, and the instantaneous high pressure will cause the gas to be discharged toward one side of the electrode lead-out portion 3, damaging the electrode lead-out portion 3, which will result in a failure of the electrical connection of the battery cell 100.

[0240] In some embodiments, the electrode lead portion 3 is provided on a first end wall 13 of the case 10, a first through hole 12 for attaching the electrode lead portion 3 is provided on the first end wall 13, the pressure relief member 21 is circular and has a pressure relief area, and the diameter φ2 of the first through hole 12 and the diameter φ1 of the pressure relief area satisfy the relationship φ2≦φ1.

[0241] If φ2>φ1, when thermal runaway occurs inside the battery cell 100, the amount of deformation on the pressure relief member 21 side is smaller than the amount of deformation on the first end wall 13 side, and the attachment area of ​​the electrode lead portion 3 is likely to be damaged and heat leakage will occur. To achieve better results, φ2≦0.8*φ1 is set.

[0242] In this embodiment, by making the diameter φ2 of the first through hole 12 for attaching the electrode lead portion 3 equal to or smaller than the diameter φ1 of the pressure relief area, the strength of the first end wall 13 on which the electrode lead portion 3 of the case 10 is provided can be strengthened, and when thermal runaway occurs in the battery cell 100, gas can flow preferentially toward the pressure relief member 21, preventing the area in which the first end wall 13 is located from being significantly deformed under the action of the high-pressure gas inside, preventing the case 10 from being damaged in the event of thermal runaway and causing heat leakage, and improving safety on the side of the battery cell 100 on which the electrode lead portion 3 and first end wall 13 are located.

[0243] In some embodiments, the size range of the diameter φ2 of the first through hole 12 is 8 mm≦φ2≦25 mm and / or the size range of the diameter φ1 of the pressure relief area is 20 mm≦φ1≦35 mm.

[0244] In order to achieve excellent effect, 10mm≦φ2≦20mm, 22mm≦φ1≦32mm.

[0245] The first through hole 12 is used to attach the electrode lead portion 3. If the size of the first through hole 12 is too small, the diameter of the electrode lead portion 3 will be limited, affecting the overflow capacity of the battery cell 100. If the size of the first through hole 12 is too large, it will reduce the overall strength of the first end wall 13 that is far from the end cover 2 of the storage section 1. If thermal runaway occurs in the battery cell, the connection portion between the first through hole 12 and the electrode lead portion 3 will be easily deformed, and gas will escape from the thin portion and affect the safety on the side where the electrode lead portion 3 and the first end wall 13 are located.

[0246] In this embodiment, by designing the diameter φ1 of the first through hole 12 and the pressure relief area to be of appropriate size, the strength of one end of the case 10 having the electrode lead-out portion 3 can be ensured, and when thermal runaway occurs in the battery cell 100, gas can flow preferentially toward the pressure relief member 21, preventing the area where the first end wall 13 is located from being significantly deformed under the action of the high-pressure gas inside, preventing the case 10 from being damaged in the event of thermal runaway and causing heat leakage, and improving safety on the side of the battery cell 100 where the electrode lead-out portion 3 and first end wall 13 are located.

[0247] In some embodiments, the electrode assembly 4 is formed by winding a first electrode sheet 45 and a second electrode sheet 46 having opposite polarities and a partition member 47 around a winding axis K, the winding axis K coincides with a first direction z, and the first electrode sheet 45 and the second electrode sheet 46 have a first tab 42 and a second tab 43, respectively. A second through hole 44 extending along the first direction z is provided at the center of the electrode assembly 4, the pressure relief member 21 is circular and has a pressure relief area, and the maximum diameter φ3 of the second through hole 44 and the diameter φ1 of the pressure relief area satisfy the relationship φ3≧0.12*φ1.

[0248] In order to achieve a better effect, φ3≧0.15*φ1, so that when thermal runaway occurs in the battery cell 100, the gas can quickly reach the pressure relief member 21 along the second through-hole 44.

[0249] [Table 4]

[0250] In Example 1 of Table 4, φ3<0.12*φ1, and when a needling failure test is performed near the side where the electrode lead-out portion 3 and the first end wall 13 are located, if a short circuit occurs in the battery cell 100 and internal thermal runaway occurs, the diameter of the second through hole 44 is too small, so the high-temperature, high-pressure gas cannot reach the pressure relief member 21 along the second through hole 44 in a timely manner, and the discharge speed is slow, and the instantaneous high pressure causes the gas to be discharged toward one side of the electrode lead-out portion, damaging the electrode lead-out portion, and causing a failure of the electrical connection of the battery cell 100.

[0251] In this embodiment, the diameter φ3 of the second through hole 44 and the diameter φ1 of the pressure relief area satisfy the above relationship, so that when thermal runaway occurs in the battery cell 100, the second through hole 44 has a sufficient passage size to allow the high-pressure gas inside to flow quickly to the pressure relief member 21, allowing the pressure relief member 21 to be released smoothly, and heat is not easily accumulated inside the battery cell 100 and dissipated, preventing the case 10 from being significantly deformed and damaged, resulting in heat leakage, and thereby improving the operational safety of the battery cell 100.

[0252] In some embodiments, the height of the battery cell 100 along the first direction z is h, where 60 mm≦h≦135 mm.

[0253] To achieve a good effect, h can be selected between 70mm and 125mm. If h<60mm, the height of the battery cell 100 is insufficient, and the power of the entire power battery system is low. If h>135mm, it is difficult to provide space for the pressure relief member 21 to discharge the waste at the bottom of the battery 200, and a single battery cell 100 will explode after thermal runaway, and the entire battery 200 will catch fire and explode.

[0254] In this embodiment, by setting the battery cell 100 at an appropriate height, it is possible to ensure sufficient power for the entire battery system and to fully utilize the internal space of the battery 200. It is also possible to provide space in the bottom area of ​​the battery 200 for the pressure relief member 21 to discharge waste materials. In the event of thermal runaway, this ensures smooth discharge of waste materials from the battery cell 100 and prevents the battery 200 from catching fire or exploding due to an instantaneous increase in temperature and pressure.

[0255] In some embodiments, the case 10 is cylindrical, and the case 10 has a diameter φ and a height h, where h / φ≦3.5.

[0256] To achieve a good effect, h / φ≦3. If h / φ>3.5, it is not appropriate to adopt a structure in which the electrode lead-out part 3 and the pressure relief member 21 are provided at both opposing ends of the case 10, because the battery cell 100 has an elongated shape, and when thermal runaway occurs at a certain portion in the battery cell 100 close to the electrode lead-out part 3, the internal gas cannot flow in a timely manner to the end where the pressure relief member 21 is located, so that a lot of heat is collected and the gas is more likely to erupt from the area where the electrode lead-out part 3 is located, which may cause a safety incident such as a fire in the entire power battery system.

[0257] Table 5 below explains the effect of h / φ on the safety of the battery cell 100, and all size parameters in the table below are in mm.

[0258] [Table 5]

[0259] In Table 5, for Examples 5, 6, and 9, h / φ>3.5, the height-to-diameter ratio of the battery cell 100 is large, and the battery cell 100 has an elongated shape. When a needling failure test is performed near the side where the electrode lead-out portion 3 and the first end wall 13 are located, if a short circuit occurs in the battery cell 100 and thermal runaway occurs inside, the high-temperature, high-pressure gas cannot reach the pressure relief member 21 in a timely manner or cannot be discharged from the pressure relief member 21, and the gas is discharged toward one side of the electrode lead-out portion, damaging the electrode lead-out portion, which causes a failure in the electrical connection of the battery cell 100. In another embodiment, when h / φ<3.5, the height-to-diameter ratio of the battery cell 100 is appropriate, and a needling failure test is performed near the side where the electrode lead-out portion 3 and the first end wall 13 are located, if a short circuit occurs in the battery cell 100 and thermal runaway occurs inside, the high-temperature, high-pressure gas can reach the pressure relief member 21 in a timely manner or be discharged from the pressure relief member 21, preventing the gas from being discharged toward one side of the electrode lead-out portion, preventing the electrode lead-out portion from being damaged, and ensuring a normal electrical connection of the battery cell 100.

[0260] In this embodiment, by setting the battery cell 100 to an appropriate height and diameter ratio, even if thermal runaway occurs in any area inside the battery cell 100, the high-pressure gas inside can quickly reach the pressure relief member 21 and be smoothly discharged, preventing the high-pressure gas and heat from accumulating inside the battery cell 100 and preventing incidents such as fire and explosion from occurring throughout the power battery system, thereby improving the safety of battery operation.

[0261] In some embodiments, as shown in FIG. 11 , the case 10 has a first end wall 13, the first end wall 13 has a first through hole 12, the electrode lead portion 3 of the battery cell 10 is attached to the first through hole 12 and is insulated from the first end wall 13, the electrode lead portion 3 is a first output pole and the first end wall 13 is a second output pole, the battery 200 further has a bus bar 202, a plurality of battery cells 100 are provided, one end of the bus bar 202 is electrically connected to the electrode lead portion 3 of one of the battery cells 100, and the other end of the bus bar 202 is electrically connected to the first end wall 13 of the other battery cell 100.

[0262] The bus bar 202 may have a thin plate structure and may be made of a metal conductive material. For example, the bus bar 202 may include a first portion 202A, a second portion 202B, and a third portion 202C, the second portion 202B being connected between the first portion 202A and the third portion 202C, the first portion 202A being connected to the electrode lead portion 3 of one of the battery cells 100, and the third portion 202C being connected to the first end wall 13 of the other battery cell 100, and the two battery cells 100 may be adjacent to each other or spaced apart from each other. For example, the shape of the first portion 202A may match the shape of the electrode lead portion 3, e.g., circular or rectangular, and the third portion 202C may be rectangular, and a notch may be provided on the side of the third portion 202C far from the second portion 202B, so as to give way to the electrode lead portion 3 of the other battery cell 100.

[0263] In this embodiment, the electrode lead portion 3 is the first output pole of the battery cell 100, and the first end wall 13 is the second output pole of the battery cell 100. By doing so, when realizing a series, parallel or mixed connection of multiple battery cells 100 inside the battery 200, both ends of the bus bar 202 can be directly connected to the electrode lead portion 3 and the first end wall 13, respectively. Since only one electrode lead portion 3 is provided on the first end wall 13 of the case 10, this is advantageous for increasing the conductive area of ​​the electrode lead portion 3. In addition, electrical connection can be easily achieved on the first end wall 13 by welding or fastener connection. This reduces the difficulty of electrically connecting the multiple battery cells 100, improves the reliability of the electrical connection, and ensures the operating performance and reliability of the battery 200.

[0264] In some embodiments, as shown in FIG. 11 , the case 10 has a first end wall 13, the first end wall 13 has a first through hole 12, the electrode lead portion 3 of the battery cell 10 is attached to the first through hole 12 and is insulated from the first end wall 13, the electrode lead portion 3 is a first output pole and the first end wall 13 is a second output pole, the battery 200 further has a plurality of bus bars 202, and in the same battery cell 100, the electrode lead portion 3 is electrically connected to one of the bus bars 202, and the first end wall 13 is electrically connected to the other bus bar 202.

[0265] In this embodiment, each battery cell 100 is electrically connected to two other battery cells 100 via two independent bus bars 202, and the area located around the electrode lead-out portion 3 of the first end wall 13 can all be connected to the bus bars 202, thereby adapting to different distribution methods of multiple battery cells 100.

[0266] In some embodiments, as shown in FIG. 12 , the battery 200 further includes a housing assembly 201 and a support plate 203, the battery cell 100 is mounted in the housing assembly 201 by the support plate 203, the support plate 203 is provided with a third through hole 203′, the third through hole 203′ is used for the flow of exhaust escaping through the pressure relief member 21, the pressure relief member 21 is circular and has a pressure relief area, and the minimum distance D between the pressure relief member 21 and the inner wall of the housing assembly 201 and the diameter φ1 of the pressure relief area satisfy the relationship: 0.4*φ1≦D≦1.2*φ1.

[0267] For example, the support plate 203 is provided on the inner bottom surface of the housing assembly 201, the support plate 203 is provided with a plurality of third through holes 203', the pressure relief members 21 of the plurality of battery cells 100 are all attached to the support plate 203 facing downward, the pressure relief members 21 and the third through holes 203' have weight portions, for example, the pressure relief members 21, the third through holes 203' and the end cover 2 are concentrically provided. The third through holes 203' are used for exhaust material leaking from the inside of the battery cells 100 to flow to an exhaust passage in the battery 200, and finally the exhaust material is exhausted to the outside through the pressure relief member on the housing assembly 201 of the battery 200.

[0268] The distance D is designed according to the diameter φ1 of the pressure relief area. In order to achieve a good effect, 0.67*φ1≦D≦φ1. If D<0.4*φ1, the distance D between the pressure relief member 21 and the inner wall of the housing assembly 201 is too small, the active material cannot be effectively ejected, and the battery 200 cannot be cooled quickly. If D>1.2*φ1, the distance D between the pressure relief member 21 and the inner wall of the housing assembly 201 is too large, which occupies the height of the battery cell 100 and affects the energy density.

[0269] For example, the size range of φ1 is 20 mm to 35 mm, and preferably 22 mm to 32 mm. The size range of D is 10 mm to 30 mm, and preferably 15 mm to 25 mm.

[0270] Table 6 below explains the effect of the distance D design on the drop in temperature to a preset value after battery thermal runaway, and the unit of each size parameter in the table below is mm.

[0271] [Table 6]

[0272] In Example 1, D<0.67*φ1, and the distance D is too small, so that when thermal runaway occurs in the battery cell 100, the waste cannot be discharged in a timely manner through the third through-hole 203', and the internal temperature of the battery 200 rises rapidly, and the time required to reduce to 120° C. is twice as long as that of the other examples. In Example 4, D>1.2*φ1, and the distance D is too large, so that when thermal runaway occurs in the battery cell 100, the waste cannot be discharged in a timely manner through the third through-hole 203', and the thickness of the support plate 203 is too large, which significantly reduces the height of the battery cell 100 and affects the energy density of the battery cell 100.

[0273] In this embodiment, by setting an appropriate distance D between the pressure relief member 21 and the inner wall of the housing assembly 201, when thermal runaway occurs in the battery cell 100, the internal gas and active material can be effectively ejected, and the temperature of the battery 200 can be quickly reduced. Furthermore, while ensuring safety against thermal runaway, the height of the battery cell 100 can be increased as much as possible, thereby increasing the energy density of the battery cell 100 and enabling the battery 200 to provide greater power.

[0274] In some embodiments, the power consumption device comprises a vehicle 300, the battery 200 is disposed between a cockpit 301 and a vehicle floor 302, the electrode lead-out portion is disposed toward the cockpit 301, and the pressure relief member 21 is disposed toward the vehicle floor 302.

[0275] In this embodiment, if thermal runaway occurs during use of the battery 200, the pressure relief member 21 of the battery cell 100 is provided toward the vehicle floor 302, i.e., facing downward, so that when the pressure relief member 21 is opened, the waste material discharged from the battery 200 is ejected below the vehicle, reducing the impact of high temperature and pressure on the cockpit 301 and occupants, and improving the safety of the vehicle 300 during use.

[0276] 3 to 5, in some specific embodiments, the battery cell 100 is cylindrical and includes a case 10, an electrode assembly 4, and an electrode lead-out portion 3. The case 10 includes a storage section 1 and an end cover 2, the storage section 1 has a cylindrical tubular structure and has an opening 11 at one end along a first direction z (central axis), and the end cover 2 closes the opening 11. The storage section 1 includes a first end wall 13 and a side wall 15, and the end cover 2 includes a second end wall 14.

[0277] A pressure relief member 21 is provided integrally with the end cover 2, the pressure relief member 21 is circular, and is provided at the center of the end cover 2. A first through hole 12 is provided in the first end wall 13, the first through hole 12 being provided at the center of the first end wall 13, and the electrode lead portion 3 is attached to the first through hole 12.

[0278] The electrode assembly 4 includes an electrode body 41, a first tab 42, and a second tab 43, the first tab 42 and the second tab 43 being located at both ends of the electrode body 41 along a first direction z, respectively, which coincides with the winding axis. The first tab 42 is electrically connected to the electrode lead 3 via the first current collecting member 5, the second tab 42 is electrically connected to the end cover 2 via the second current collecting member 6, the end cover 2 being welded to the housing 1, and the second tab 43 transmits electrical energy to the first end wall 13 via the second current collecting member 6, the end cover 2, and the side wall 15. For example, the electrode lead 3 is a positive output pole and the first end wall 13 is a negative output pole, or vice versa.

[0279] Although the present application has been described with reference to the preferred embodiments, various modifications may be made and parts therein may be replaced with equivalents without departing from the scope of the present application. In particular, the technical features mentioned in each embodiment may be combined in any manner as long as there is no structural contradiction. The present application is not limited to the specific embodiments disclosed in the present specification, but includes all technical means included in the scope of the claims.

[0280] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure is based on and claims priority to a PCT application having application number PCT / CN2022 / 101981, filed June 28, 2022, the disclosure of which is hereby incorporated in its entirety into this disclosure. [Explanation of symbols]

[0281] 100, battery cell 10, case 1, storage section 11, opening 12, first through hole 13, first end wall 14, second end wall 15, side wall 2, end cover 21, pressure relief member 22, notch 23, recessed portion 3, electrode lead-out portion 31, main body portion 32, base 33, limit protrusion portion 34, recess 341, first recess 342, second recess 343, third through hole 4, electrode assembly 41, electrode body 42, first tab 43, second tab 44, second through hole 45, first electrode sheet 45', first coating layer 46, second electrode sheet 46', second coating layer 47, separator 5, first current collecting member 6, second current collecting member 6', cut-out portion 61, fourth through hole 62, scale 63, notch 7, insulating member 8, plate cover K, winding axis z, first direction y, second direction x, third direction 200, battery 201, housing assembly 201A, housing part 201B, first cover 201C, second cover 202, bus bar 202A, first part 202B, second part 202C, third part 203, support plate 203', third through hole 300, vehicle 301, cockpit 302, floor.

Claims

1. A battery cell, an electrode assembly (4) comprising an electrode body (41) and a first tab (42) and a second tab (43) having opposite polarities, the first tab (42) and the second tab (43) being led out from the electrode body (41); a first output pole electrically connected to the first tab (42) and a second output pole electrically connected to the second tab (43); a case (10) used to house the electrode assembly (4), provided with a pressure relief member (21), and having, along a first direction (z), the first output pole and the second output pole at one end and the pressure relief member (21) at the other end.

2. The case (10) comprises a first end wall (13) and a second end wall (14) that are provided opposite each other along the first direction (z), and a side wall (15) located between the first end wall (13) and the second end wall (14), a first through hole (12) is provided in the first end wall (13), an electrode lead-out portion (3) of the battery cell (10) is attached to the first through hole (12) and is provided insulated from the first end wall (13), and the pressure relief member (21) is provided on the second end wall (14), 2. The battery cell according to claim 1, wherein the electrode lead portion (3) is the first output pole, and the first end wall (13) is the second output pole.

3. 3. The battery cell of claim 2, wherein the case (10) comprises a storage section (1) and an end cover (2), the storage section (1) having an opening (11), the end cover (2) being used to cover the opening (11), the storage section (1) being formed by the first end wall (13) and the side wall (15), and the end cover (2) being the second end wall (14).

4. 3. The battery cell of claim 2, wherein the case (10) comprises a storage section (1) and an end cover (2), the storage section (1) has an opening (11), the end cover (2) is used to cover the opening (11), the storage section (1) is formed by the second end wall (14) and the side wall (15), and the end cover (2) is the first end wall (13).

5. The battery cell according to any one of claims 2 to 4, wherein the first tab (42) is drawn out from the electrode main body (41) in a direction facing the electrode lead-out portion (3) in the first direction (z), the second tab (43) is drawn out from the electrode main body (41) in a direction away from the electrode lead-out portion (3) in the first direction (z), the first tab (42) is electrically connected to the electrode lead-out portion (3), and the second tab (43) is electrically connected to the first end wall (13).

6. 6. The battery cell according to claim 5, further comprising a first current collecting member (5) and a second current collecting member (6), wherein the first tab (42) is electrically connected to the electrode lead portion (3) via the first current collecting member (5), and the second tab (43) is electrically connected to the first end wall (13) via the second current collecting member (6).

7. 7. The battery cell of claim 6, wherein the second current collecting member (6) is in contact with the side wall (15) to provide electronic continuity between the second tab (43) and the first end wall (13).

8. 7. The battery cell of claim 6, wherein the case (10) comprises a storage portion (1) and an end cover (2), the storage portion (1) has an opening (11), the end cover (2) is used to cover the opening (11), the second current collecting member (6) is connected to the end cover (2), and the end cover (2) is electrically connected to the side wall (15) to realize electronic conduction between the second tab (43) and the first end wall (13).

9. 7. The battery cell of claim 6, wherein the case (10) comprises a storage portion (1) and an end cover (2), the storage portion (1) has an opening (11), the end cover (2) is used to cover the opening (11), the second current collecting member (6) is in contact with the side wall (15), and the end cover (2) is connected to the second current collecting member (6) to realize electronic conduction between the second tab (43) and the first end wall (13).

10. The battery cell according to any one of claims 6 to 9, wherein along the first direction (z), the second current collecting member (6) is located between the pressure relief member (21) and the second tab (43), and the second current collecting member (6) is provided with a cut-out portion (6'), and the cut-out portion (6') is used for gas communication between a space on one side of the second current collecting member (6) facing the second tab (43) and a space on the other side facing the pressure relief member (21).

11. The battery cell according to claim 10, wherein the cutout portion (6') has at least one fourth through hole (61), one of the fourth through holes (61) being provided at a central position of the second current collecting member (6).

12. The battery cell according to claim 11, wherein a plurality of the fourth through holes (61) are provided, and the other fourth through holes (61) are distributed around the fourth through hole (61) located at a central position.

13. The battery cell of claim 11, wherein the cutout portion (6') further comprises a plurality of notches (63), the notches (63) penetrating the second current collecting member (6) along the first direction (z), and the plurality of notches (63) are surrounded by the fourth through hole (61).

14. The battery cell according to claim 13 , wherein one end of the notch (63) is connected to the fourth through hole (61) and extends in a direction away from the fourth through hole (61).

15. 12. The battery cell of claim 11, wherein the cutout portion (6') further comprises a scale (62), the scale (62) penetrating the second current collecting member (6) along the first direction (z).

16. The battery cell according to claim 15, wherein a plurality of the scales (62) are provided, and one end of the scales (62) is connected to the fourth through hole (61) and extends in a direction away from the fourth through hole (61).

17. The battery cell according to any one of claims 2 to 4, wherein the first tab (42) and the second tab (43) are both drawn out from one end of the electrode body (41) facing the electrode lead-out portion (3) along the first direction (z), the first tab (42) being electrically connected to the electrode lead-out portion (3), and the second tab (43) being electrically connected to the first end wall (13).

18. The battery further includes a first current collecting member (5) and a second current collecting member (6), the first tab (42) being electrically connected to the electrode lead portion (3) via the first current collecting member (5), and the second tab (43) being electrically connected to the first end wall (13) via the second current collecting member (6), The battery cell of any one of claims 2 to 17, wherein the electrode lead portion (3) comprises a base (31) and a main body portion (32), the base (31) is located between the first end wall (13) and the first current collecting member (5) and is used to limit movement of the electrode lead portion (3) along the first direction (z) in a direction away from the interior of the case (10), an insulating member (7) is provided between the first end wall (13) and the base (31), and at least a portion of the main body portion (32) is located within the first through hole (12).

19. 19. The battery cell of claim 18, wherein along the first direction (z), a maximum thickness t1 of the base (31) satisfies 0.6 mm≦t1≦1.2 mm, and / or a maximum thickness t2 of the first current collecting member (5) satisfies 0.3 mm≦t2≦0.7 mm, and / or a maximum thickness t3 of the second current collecting member (6) satisfies 0.3 mm≦t3≦0.7 mm.

20. 20. The battery cell of claim 19, wherein 0.8 mm≦t1≦1 mm, and / or 0.4 mm≦t2≦0.6 mm, and / or 0.4 mm≦t3≦0.6 mm.

21. A battery cell as described in any one of claims 18 to 20, wherein the electrode lead portion (3) further comprises a limit protrusion (33), the base (31) and the limit protrusion (33) are both connected to and protrude from the outer peripheral wall of the main body portion (32), the limit protrusion (33) and the base (31) are respectively located on the outside and inside of the first end wall (13) along the first direction (z), and are used to clamp a portion of the first end wall (13).

22. 22. A battery cell as described in claim 21, wherein the main body portion (32) is provided with a recess (34), the bottom wall of the recess (34) is connected to the first current collecting member (5) and realizes electronic conduction between the electrode lead portion (3) and the first tab (42), and the opening of the recess (34) is provided on one side of the main body portion (32) facing and / or facing away from the inside of the case (10).

23. 23. The battery cell according to claim 22, wherein the bottom wall of the recess (34) and the first current collecting member (5) are laser welded from one side of the body portion (32) facing away from the inside of the case (10).

24. The battery cell of any one of claims 2 to 23, wherein the case (10) is cylindrical, the pressure relief member (21) is provided at the center position of the second end wall (14) and is circular, the pressure relief member (21) has a pressure relief area, and a diameter φ1 of the pressure relief area and a diameter φ of the case (10) satisfy the relationship: 0.35≦φ1 / φ≦0.

85.

25. 25. The battery cell (100) of claim 24, wherein 15 mm≦φ≦70 mm.

26. The battery cell according to any one of claims 2 to 25, wherein a thickness l1 of the first end wall (13) and a thickness l2 of the second end wall (14) satisfy the relationship l1 ≧ l2.

27. 27. The battery cell of claim 26, wherein l1 >= 1.5*l2.

28. 28. The battery cell of claim 26 or 27, wherein the size range of the thickness l1 of the first end wall (13) is 0.5 mm≦l1≦1 mm, and / or the size range of the thickness l2 of the second end wall (14) is 0.3 mm≦l2≦1 mm.

29. 29. The battery cell of claim 28, wherein 0.6 mm≦l1≦0.8 mm, and / or 0.5 mm≦l2≦0.8 mm.

30. The battery cell of any one of claims 2 to 29, wherein a notch (22) is provided in the second end wall (14), and an area of ​​the second end wall (14) surrounded by the notch (22) forms the pressure relief member (21).

31. The battery cell of claim 30, wherein a thickness l1 of the first end wall (13) and a thickness l3h of the second end wall (14) at a location where the notch (22) is provided satisfy the relationship l1 ≧ 2 * l3.

32. 32. The battery cell of claim 31, wherein l1 >= 6*l3.

33. The battery cell according to any one of claims 2 to 32, wherein the pressure relief member (21) is circular and has a pressure relief area, and a diameter φ2 of the first through hole (12) and a diameter φ1 of the pressure relief area satisfy the relationship φ2≦φ1.

34. 34. The battery cell of claim 33, wherein the size range of the diameter φ2 of the first through hole (12) is 8 mm≦φ2≦25 mm, and / or the size range of the diameter φ1 of the pressure relief area is 20 mm≦φ1≦35 mm.

35. The electrode assembly (4) is formed by winding a first electrode sheet (45) and a second electrode sheet (46) having opposite polarities and a partition member (47) around a winding axis (K), the winding axis (K) coincides with the first direction (z), and the first electrode sheet (45) and the second electrode sheet (46) have the first tab (42) and the second tab (43), respectively; The battery cell of any one of claims 1 to 34, wherein a second through hole (44) extending along the first direction (z) is provided at the center of the electrode assembly (4), the pressure relief member (21) is circular and has a pressure relief area, and a maximum diameter φ3 of the second through hole (44) and a diameter φ1 of the pressure relief area satisfy the relationship φ3 ≧ 0.12 * φ1.

36. The battery cell of any one of claims 1 to 35, wherein the case (10) has a second end wall (14), and the pressure relief member (21) is located in a central region of the second end wall (14).

37. A battery comprising a battery cell (100) according to any one of claims 1 to 36.

38. the case (10) has a first end wall (13), a first through hole (12) is provided in the first end wall (13), an electrode lead portion (3) of a battery cell (10) is attached to the first through hole (12) and is provided insulated from the first end wall (13), the electrode lead portion (3) is the first output pole, and the first end wall (13) is the second output pole, The battery (200) further comprises a bus bar (202), wherein a plurality of the battery cells (100) are provided, one end of the bus bar (202) is electrically connected to the electrode lead portion (3) of one of the battery cells (100), and the other end of the bus bar (202) is electrically connected to the first end wall (13) of another of the battery cells (100).

39. the case (10) has a first end wall (13), a first through hole (12) is provided in the first end wall (13), an electrode lead portion (3) of a battery cell (10) is attached to the first through hole (12) and is provided insulated from the first end wall (13), the electrode lead portion (3) is the first output pole, and the first end wall (13) is the second output pole, The battery (200) further comprises a plurality of bus bars (202), and in the same battery cell (100), the electrode lead portion (3) is electrically connected to one of the bus bars (202) and the first end wall (13) is electrically connected to another bus bar (202).

40. The battery (200) further comprises a support plate (203) and a housing assembly (201), the battery cell (100) is mounted in the housing assembly (201) by the support plate (203), the support plate (203) is provided with a third through hole (203'), the third through hole (203') is used for a flow of exhaust escaping from the pressure relief member (21), the pressure relief member (21) is circular and has a pressure relief area, and a minimum distance D between the pressure relief member (21) and an inner wall of the housing assembly (201) and a diameter φ1 of the pressure relief area satisfy the relationship: 0.4*φ1≦D≦1.2*φ1.

41. A power consuming device comprising a battery (200) according to any one of claims 37 to 40, said battery (200) being used to provide electrical energy to said power consuming device.

42. 42. The power consuming device of claim 41, comprising a vehicle (300), the battery (200) being arranged between a cockpit (301) and a vehicle floor (302), the first output pole and the second output pole both being arranged toward the cockpit (301), and the pressure relief member (21) being arranged toward the vehicle floor (302).

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