Battery cells, batteries and electrical devices

Abstract

The embodiment of the present application provides a battery cell, a battery and an electrical device, wherein the battery cell (100) comprises: an electrode assembly (4), comprising an electrode body (41) and a first pole lug (42) and a second pole lug (43) with opposite polarities, wherein the first pole lug (42) and the second pole lug (43) are led out from the electrode body (41); a first output pole and a second output pole, wherein the first output pole is electrically connected to the first pole lug (42) and the second output pole is electrically connected to the second pole lug (43); and a shell (10) for accommodating the electrode assembly (4), wherein the shell (10) is provided with a pressure relief component (21), wherein along a first direction (z), the first output pole and the second output pole are arranged at one end of the shell (10), and the pressure relief component (21) is arranged at the other end of the shell (10).

Description

[0001] Cross-references to related applications

[0002] This disclosure is based on application no. PCT / CN2022 / 101981 , application date is June 28, 2022 The disclosure of PCT application is incorporated herein by reference in its entirety, and the priority benefit is claimed therefrom. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0004] Lithium-ion batteries have been widely used in electric vehicles due to their advantages of high energy density, high power density, many cycles and long storage time.

[0005] However, improving the safety of batteries in electric vehicles during use has always been a difficult problem in the industry. Summary of the Invention

[0006] The purpose of this application is to improve the safety of batteries during use.

[0007] According to a first aspect of the present application, a battery cell is provided, comprising:

[0008] The electrode assembly includes an electrode body and a first electrode tab and a second electrode tab with opposite polarities, wherein the first electrode tab and the second electrode tab are led out from the electrode body;

[0009] a first output pole and a second output pole, the first output pole being electrically connected to the first tab, and the second output pole being electrically connected to the second tab;

[0010] The shell is used to accommodate the electrode assembly. The shell is provided with a pressure relief component. Along the first direction, the first output pole and the second output pole are arranged at one end of the shell, and the pressure relief component is arranged at the other end of the shell.

[0011] In this embodiment, the first and second output poles are located at one end of the housing, and the pressure relief component is located at the other end of the housing. When thermal runaway occurs inside the battery cell, the active material will be ejected from the end where the pressure relief component is located, away from the first and second output poles of the battery cell, and thus away from the busbar used to electrically connect multiple battery cells. This can reduce the impact on the electrical connection of the battery cell when thermal runaway occurs, prevent large-scale short circuits or high-voltage sparks in the battery, and avoid causing thermal runaway of the entire power battery system, or even fire and explosion, thereby improving the safety of the power battery system. Secondly, arranging the pressure relief component and the output pole at both ends of the housing provides more space for the pressure relief component, which can improve the current capacity of the output pole, and also facilitates the processing of the pressure relief component and more accurately controls its opening pressure. It also prevents welding stress from affecting the opening pressure of the pressure relief component when welding the busbar. In addition, arranging the first and second output poles at the same end of the housing facilitates the installation and connection of the busbar when electrically connecting multiple battery cells.

[0012] In some embodiments, the shell includes a first end wall, a second end wall and a side wall located between the first end wall and the second end wall, which are arranged opposite to each other along a first direction. The first end wall is provided with a first through hole, the electrode lead-out portion of the battery cell is installed in the first through hole and is insulated from the first end wall, and the second end wall is provided with a pressure relief component; the electrode lead-out portion is the first output pole, and the first end wall is the second output pole.

[0013] In this embodiment, the electrode lead-out portion and the first end wall are arranged at the same end of the shell, and the pressure relief component is arranged at the other end of the shell. When thermal runaway occurs inside the battery cell, the active material will be ejected from the end where the pressure relief component is located, away from the electrode lead-out portion and the first end wall of the battery cell, and thus away from the busbar used to electrically connect multiple battery cells, which can reduce the impact on the electrical connection of the battery cells when thermal runaway occurs.

[0014] In some embodiments, the housing includes: a receiving portion and an end cover, the receiving portion has an opening, the end cover is used to cover the opening, the receiving portion is formed by a first end wall and a side wall, and the end cover is the second end wall.

[0015] This embodiment arranges the pressure relief component on an end cover independent of the accommodating portion, which can reduce the process difficulty of setting the pressure relief component, make it more convenient to set the pressure relief component integrally on the end cover, and make it easier to control the dimensional accuracy of the weak area of the pressure relief component during processing, so as to improve the setting accuracy of the opening pressure of the pressure relief component. When thermal runaway occurs in the battery cell, the pressure relief component can be reliably opened, thereby improving the safety of the battery cell operation.

[0016] Moreover, since the first output pole and the second output pole are both arranged on the first end wall integrally provided with the side wall, and not on the end cover, the pulling of the busbar on the connection between the end cover and the side wall is reduced, fatigue is prevented at the connection, and the influence of the busbar on the pressure relief component is reduced. To a certain extent, the damage to the pressure relief component during normal use of the battery cell is reduced, and premature pressure relief is prevented.

[0017] In some embodiments, the housing includes: a receiving portion and an end cover, the receiving portion has an opening, the end cover is used to cover the opening, the receiving portion is formed by a second end wall and a side wall, and the end cover is the first end wall.

[0018] In this embodiment, the electrode lead-out portion is provided on an end cover that is independent of the accommodation portion, and the electrode lead-out portion can be conveniently mounted on the end cover.

[0019] In some embodiments, the first pole tab is extended from the electrode body along the first direction facing the electrode lead portion, and the second pole tab is extended from the electrode body along the first direction away from the electrode lead portion. The first pole tab is electrically connected to the electrode lead portion, and the second pole tab is electrically connected to the first end wall.

[0020] In this embodiment, the first electrode tab and the second electrode tab are respectively led out from both ends of the electrode body, which can improve the current carrying capacity and easily ensure the insulation reliability between the first electrode tab and the second electrode tab, thereby improving the working performance of the battery cell.

[0021] In some embodiments, the battery cell further includes a first current collector and a second current collector, the first electrode tab is electrically connected to the electrode lead portion through the first current collector, and the second electrode tab is electrically connected to the first end wall through the second current collector.

[0022] In this embodiment, the first electrode tab is electrically connected to the electrode lead portion through the first current collecting member, and the second electrode tab is electrically connected to the first end wall through the second current collecting member, which can facilitate welding with the electrode tabs and improve the reliability of the electrical connection between the first electrode tab and the electrode lead portion, as well as the reliability of the electrical connection between the second electrode tab and the first end wall.

[0023] In some embodiments, the second current collecting member contacts the side wall to achieve electronic conduction between the second electrode tab and the first end wall.

[0024] This embodiment can reduce the number of steps for the second electrode tab to transmit electrical energy to the first end wall, thereby improving the reliability of electrical energy transmission.

[0025] In some embodiments, the shell includes: a accommodating portion and an end cover, the accommodating portion has 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 achieve electronic conduction between the second electrode tab and the first end wall.

[0026] This embodiment electrically connects the second electrode tab to the end cap. For example, when welding is used to achieve electrical connection, the end cap has a relatively flat welding surface, which facilitates welding and provides a better welding effect, thereby improving the reliability of the electrical connection between the second electrode tab and the first end cap.

[0027] In some embodiments, the shell includes: a accommodating portion and an end cover, the accommodating portion has an opening, the end cover is used to cover the opening, the second current collecting member contacts the side wall, and the end cover is connected to the second current collecting member to achieve electronic conduction between the second electrode tab and the first end wall.

[0028] This embodiment allows the electric energy transmitted by the second tab to be transferred to the first end cap through two conductive paths. When a virtual connection occurs in one of the conductive paths, the electric energy can continue to be transmitted through the other conductive path, thereby improving the reliability of electric energy transmission.

[0029] In some embodiments, along the first direction, the second current collecting member is located between the pressure relief member and the second electrode tab, and a hollow portion is provided on the second current collecting member, which is used to conduct gas between the space on one side of the second current collecting member facing the second electrode tab and the space on the other side facing the pressure relief member.

[0030] This embodiment takes into account that the electrode lead-out portion and the pressure relief component are arranged at opposite ends of the shell. By providing a hollow portion on the second current collecting member, when thermal runaway occurs in any area inside the battery cell, high-temperature and high-pressure gas can smoothly pass through the hollow portion to reach the pressure relief component, so as to be discharged outward in a timely manner through the pressure relief component, thereby improving the safety of the battery cell when thermal runaway occurs.

[0031] In some embodiments, the hollow portion includes at least one fourth through hole, wherein one fourth through hole is disposed at a central position of the second current collecting member.

[0032] Normally, the gas in the electrode assembly is discharged to the outside of the electrode assembly through the electrode tab side. By setting a fourth through hole in the center of the second current collector, the gas discharged from various areas of the second electrode tab can reach the fourth through hole relatively promptly, thereby smoothly reaching the pressure relief component.

[0033] In some embodiments, a plurality of fourth through holes are provided, and the remaining fourth through holes are distributed around the fourth through hole located at the center.

[0034] This embodiment can reasonably increase the exhaust area and, to a certain extent, solve the problem of untimely exhaust caused by blockage at the center of the second collecting member.

[0035] In some embodiments, the hollow portion further includes a plurality of cutouts, the cutouts penetrate the second current collecting member along the first direction, and the plurality of cutouts surround the fourth through hole.

[0036] This embodiment incorporates multiple cutouts in addition to the fourth through-hole to assist in venting. In the event of thermal runaway of a battery cell, air can simultaneously pass through the fourth through-hole and the multiple cutouts to reach the pressure relief component. Furthermore, the elongated cutouts facilitate venting while minimizing the impact on the strength of the second current collector, facilitating fabrication.

[0037] In some embodiments, one end of the cutout is connected to the fourth through hole and extends in a direction away from the fourth through hole.

[0038] This embodiment can achieve reliable exhaust from the center to the periphery of the second current collecting member. When thermal runaway occurs in the battery cell, the air flow can flow to the pressure relief component more smoothly and promptly.

[0039] In some embodiments, the hollow portion further includes a score line, and the score line passes through the second current collecting member along the first direction.

[0040] This embodiment incorporates multiple scorelines in addition to the fourth through-hole to aid in venting. In the event of thermal runaway of a battery cell, airflow can simultaneously pass through the fourth through-hole and the scorelines to the pressure relief component. Furthermore, the scorelines minimize any weakening of the second current collector while achieving venting.

[0041] In some embodiments, a plurality of score lines are provided, and one end of the score line is connected to the fourth through hole and extends in a direction away from the fourth through hole.

[0042] This embodiment can achieve reliable exhaust from the center to the periphery of the second current collecting member. When thermal runaway occurs in the battery cell, the air flow can flow to the pressure relief component more smoothly and promptly.

[0043] In some embodiments, the first electrode tab and the second electrode tab are both extended from one end of the electrode body facing the electrode lead portion along the first direction, the first electrode tab is electrically connected to the electrode lead portion, and the second electrode tab is electrically connected to the first end wall.

[0044] This embodiment allows the first electrode tab and the second electrode tab to be led out from one end of the electrode body facing the electrode lead-out portion, which facilitates electrical connection. Moreover, the first electrode tab and the second electrode tab only need to occupy space on a single side of the electrode body, which can shorten the height of the battery cell and is beneficial to improving the energy density of the battery cell.

[0045] In some embodiments, the battery cell further includes a first current collector and a second current collector, the first electrode tab is electrically connected to the electrode lead portion through the first current collector, and the second electrode tab is electrically connected to the first end wall through the second current collector;

[0046] The electrode lead-out portion includes a base and a main body. The base is located between the first end wall and the first current collecting member and is used to limit the movement of the electrode lead-out portion along the first direction away from the interior of the shell. An insulating member is provided between the first end wall and the base, and at least a portion of the main body is located in the first through hole.

[0047] The electrode lead portion of this embodiment can be prevented from falling out of the first through hole by the limiting effect of the base, thereby improving the reliability of the electrical connection between the electrode lead portion and the first current collector, and can also achieve insulation between the electrode lead portion and the first end wall through the insulating member.

[0048] In some embodiments, along the first direction, the maximum thickness t1 of the base satisfies: 0.6mm≤t1≤1.2mm; and / or the maximum thickness t2 of the first current collecting member satisfies: 0.3mm≤t2≤0.7mm; and / or the maximum thickness t3 of the second current collecting member satisfies: 0.3mm≤t3≤0.7mm.

[0049] This embodiment ensures that gas is discharged through the pressure relief component when thermal runaway occurs in the battery cell by setting appropriate thicknesses for the base of the electrode lead-out portion, the first current collecting member, and the second current collecting member, thereby preventing gas from ejecting from the side where the electrode lead-out portion and the first end wall are set, thereby improving the safety of the battery cell operation.

[0050] 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.

[0051] In some embodiments, the electrode lead-out portion also includes a limiting protrusion, and the base and the limiting protrusion are both connected to and protrude from the outer peripheral wall of the main body. The limiting protrusion and the base are respectively located on the outer side and inner side of the first end wall along the first direction, and are used to clamp a portion of the first end wall.

[0052] In this embodiment, the limiting protrusion and the base clamp a portion of the first end wall, so that the electrode lead-out portion can be installed on the first end wall more stably and reliably.

[0053] In some embodiments, the main body is provided with a recess, the bottom wall of the recess is connected to the first current collector to achieve electronic conduction between the electrode lead and the first electrode tab, and the opening of the recess is provided on the side of the main body facing and / or away from the interior of the shell.

[0054] In this embodiment, by providing a recess on the main body, the thickness of the region where the main body is electrically connected to the first current collector can be reduced, thereby improving the reliability of the electrical connection between the main body and the first current collector.

[0055] 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 housing from the main body.

[0056] This embodiment reduces the thickness of the welding area between the main body and the first current collector by providing a recess, and the main body and the first current collector can be conveniently welded from the outside of the electrode lead-out portion, thereby improving welding reliability; and metal ions generated by welding will not enter the shell, thereby improving the reliability of the battery cell.

[0057] In some embodiments, the housing is cylindrical, the pressure relief component is located at the center of the second end wall and is circular, and the pressure relief component has a pressure relief area. The diameter φ1 of the pressure relief area and the diameter φ of the housing satisfy the following relationship:

[0058] This embodiment sets a proportional relationship between the diameter of the pressure relief area of the pressure relief component and the diameter of the shell. When thermal runaway occurs in the battery cell, this embodiment can ensure that the pressure relief component has a sufficient opening area to quickly discharge heat from the battery cell, thereby preventing damage to the electrode lead portion or the shell or even heat leakage. Moreover, on the basis of ensuring that the pressure relief component can be opened reliably, the strength of the end of the shell where the pressure relief component is set can be improved to prevent the internal air pressure of the battery cell during normal use from causing the pressure relief component to open, resulting in leakage and abnormal electrical connection.

[0059] In some embodiments, 15 mmφ≤70 mm.

[0060] In some embodiments, the thickness l1 of the first end wall and the thickness l2 of the second end wall satisfy the following relationship: l1 ≥ l2.

[0061] This embodiment makes 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 deformation of the shell on the side of the pressure relief component is greater than the deformation on the side where the electrode lead-out portion and the first end wall are located. The gas generated by the thermal runaway can be reliably discharged from the pressure relief component on the second end wall, preventing the gas from flowing toward the side where the electrode lead-out portion is located, causing a large deformation of the first end wall, and preventing the shell from being damaged and leaking heat during thermal runaway.

[0062] In some embodiments, l1≥1.5*l2.

[0063] In some embodiments, the thickness l1 of the first end wall has a size range of 0.5 mm ≤ l1 ≤ 1 mm; and / or the thickness l2 of the second end wall has a size range of 0.3 mm ≤ l2 ≤ 1 mm.

[0064] This embodiment designs appropriate thicknesses for the first end wall and the second end wall. When thermal runaway occurs in the battery cell, the shell is deformed significantly under the action of the internal high-pressure gas, thereby preventing the shell from being damaged and leaking heat during thermal runaway.

[0065] In some embodiments, 0.6 mm ≤ l1 ≤ 0.8 mm, and / or 0.5 mm ≤ l2 ≤ 0.8 mm.

[0066] In some embodiments, the second end wall is provided with a notch, and the area of the second end wall surrounded by the notch forms a pressure relief component.

[0067] This embodiment can, when thermal runaway occurs in the battery cell, after the internal pressure exceeds the preset opening pressure of the pressure relief component, the notch ruptures to open the pressure relief component, and the air flow inside the shell is discharged outward through the opening, thereby improving the safety of the battery cell operation.

[0068] In some embodiments, the thickness l1 of the first end wall and the thickness l3 of the second end wall at the location where the notch is provided satisfy the following relationship: l1 ≥ 2*l3.

[0069] This embodiment forms a weak portion at the notch that is lower in strength than the first end wall by setting a dimensional relationship between the thickness of the first end wall and the thickness of the second end wall at the notch. When thermal runaway occurs in the battery cell, the internal gas can be deformed preferentially at the weak portion, causing the pressure relief component to open quickly, thereby allowing the internal gas to be discharged smoothly. Moreover, even if thermal runaway occurs on the side close to the electrode lead-out portion, the gas can be preferentially flowed toward the pressure relief component, thereby preventing the area where the first end wall is located from being deformed significantly under the action of the internal high-pressure gas, preventing the shell from being damaged and leaking heat during thermal runaway, and improving the safety of the battery cell on the side where the electrode lead-out portion and the first end wall are located.

[0070] In some embodiments, l1≥6*l3.

[0071] In some embodiments, the pressure relief component is circular and has a pressure relief area, and the diameter φ2 of the first through hole and the diameter φ1 of the pressure relief area satisfy the following relationship: φ2≤φ1.

[0072] In this embodiment, the diameter of the first through hole for installing the electrode lead-out portion does not exceed the diameter φ of the pressure relief zone, which can improve the strength of the first end wall of the shell where the electrode lead-out portion is set. When the battery cell experiences thermal runaway, the gas can flow preferentially toward the pressure relief component, which can prevent the area where the first end wall is located from experiencing a large deformation under the action of the internal high-pressure gas, prevent the shell from being damaged and leaking heat during thermal runaway, and improve the safety of the battery cell on the side where the electrode lead-out portion and the first end wall are located.

[0073] In some embodiments, the diameter φ2 of the first through hole is in the range of 8 mm ≤ φ2 ≤ 25 mm; and / or the diameter φ1 of the pressure relief area is in the range of 20 mm ≤ φ1 ≤ 35 mm.

[0074] This embodiment ensures the strength of the shell at one end where the electrode lead-out portion is located by designing appropriate dimensions for the diameters of the first through hole and the pressure relief area. When thermal runaway occurs in the battery cell, the gas can flow preferentially toward the pressure relief component, thereby preventing the area where the first end wall is located from undergoing a large deformation under the action of the internal high-pressure gas, preventing the shell from being damaged and leaking heat during thermal runaway, and improving the safety of the battery cell on the side where the electrode lead-out portion and the first end wall are located.

[0075] In some embodiments, the electrode assembly is formed by winding a first electrode piece, a second electrode piece, and a separator having opposite polarities around a winding axis, the winding axis being consistent with the first direction, and the first electrode piece and the second electrode piece respectively having a first electrode tab and a second electrode tab;

[0076] A second through hole extending along the first direction is provided in the center of the electrode assembly. The pressure relief component is circular and has a pressure relief area. The maximum diameter φ3 of the second through hole and the diameter φ1 of the pressure relief area satisfy the following relationship: φ3≥0.12*φ1.

[0077] In this embodiment, the diameter of the second through hole and the diameter of the pressure relief zone satisfy the above relationship. When thermal runaway occurs in the battery cell, the second through hole has a sufficient channel size to allow the internal high-pressure gas to flow quickly to the pressure relief component, so that the pressure relief component can be opened smoothly, preventing heat from accumulating inside the battery cell and being unable to be released, and preventing the shell from being significantly deformed, damaged, and leaking heat, thereby improving the safety of the battery cell operation.

[0078] In some embodiments, the housing includes a second end wall, and the pressure relief component is located in a central area of the second end wall.

[0079] In this embodiment, the pressure relief component is arranged in the central area of the end cover. When thermal runaway occurs in the battery cell, the internal high-temperature and high-pressure airflow has a shorter airflow path regardless of the direction from which it reaches the pressure relief component, so that the pressure relief component can be opened in time, thereby improving the reliability and safety of the battery cell operation.

[0080] According to a second aspect of the present application, a battery is provided, comprising the battery cell of the above embodiment.

[0081] In some embodiments, the housing includes a first end wall, the first end wall is provided with a first through hole, the electrode lead portion of the battery cell is installed in the first through hole and is 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;

[0082] The battery further includes a busbar. There are multiple battery cells. One end of the busbar is electrically connected to the electrode lead-out portion of one of the battery cells, and the other end of the busbar is electrically connected to the first end wall of another battery cell.

[0083] This embodiment uses the electrode lead-out portion as the first output pole of the battery cell and the first end wall as the second output pole of the battery cell. When realizing series connection, parallel connection or mixed connection of multiple battery cells inside the battery, the two ends of the busbar can be directly connected to the electrode lead-out portion and the first end wall respectively. Since only one electrode lead-out portion is provided on the first end wall of the shell, it is beneficial to increase the conductive area of the electrode lead-out portion, and it is also easier to realize electrical connection on the first end wall by welding or connecting with fasteners. Therefore, it can reduce the difficulty of electrical connection of multiple battery cells, improve the reliability of electrical connection, and ensure the working performance and reliability of the battery.

[0084] In some embodiments, the housing includes a first end wall, the first end wall is provided with a first through hole, the electrode lead portion of the battery cell is installed in the first through hole and is 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;

[0085] The battery further includes a plurality of current collectors. In a same battery cell, the electrode lead-out portion is electrically connected to one of the current collectors, and the first end wall is electrically connected to another current collector.

[0086] In this embodiment, each battery cell can be electrically connected to the other two battery cells through two independent busbars. Since the area around the first end wall located at the electrode lead-out portion can be used to connect the busbars, it can adapt to different arrangements of multiple battery cells.

[0087] In some embodiments, the battery further includes a support plate and a box assembly, the battery cell is installed in the box assembly through the support plate, a third through hole is provided on the support plate for allowing the discharge from the pressure relief component to flow, the pressure relief component is circular and has a pressure relief area, and the minimum distance D between the pressure relief component and the inner wall of the box assembly and the diameter φ1 of the pressure relief area satisfy the following relationship: 0.4*φ1≤D≤1.2*φ1.

[0088] This embodiment sets a suitable distance between the pressure relief component and the inner wall of the box assembly. This allows the internal gas and active material to be effectively ejected when thermal runaway occurs in the battery cell, thereby quickly cooling the battery. It also increases the height of the battery cell as much as possible while ensuring thermal runaway safety, thereby increasing the energy density of the battery cell and enabling the battery to provide greater power.

[0089] According to a third aspect of the present application, an electrical device is provided, comprising the battery of the above embodiment, wherein the battery is used to provide electrical energy to the electrical device.

[0090] In some embodiments, the electrical device includes a vehicle, the battery is disposed between a cabin and a vehicle floor, the first output pole and the second output pole are both disposed toward the cabin, and the pressure relief component is disposed toward the vehicle floor.

[0091] This embodiment enables, in the event of thermal runaway of the battery during use, since the pressure relief component of the battery cell is arranged toward the vehicle floor, that is, downward, if the pressure relief component is opened, the discharge released by the battery will be ejected toward the bottom of the vehicle, thereby reducing the impact of high temperature and high pressure on the cabin and passengers, and improving the safety of the vehicle during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0093] Figure 1 This is a schematic structural diagram of some embodiments of the present application for installing a battery on a vehicle.

[0094] Figure 2 Exploded views of some embodiments of the battery of the present application.

[0095] Figure 3 Schematic diagram of the structure of some embodiments of the battery cell of the present application.

[0096] Figure 4 Exploded views of some embodiments of the battery cells of the present application.

[0097] Figure 5 These are cross-sectional views of some embodiments of the battery cells of the present application.

[0098] Figure 6 Schematic diagrams of the structures of some embodiments of electrode assemblies.

[0099] Figure 7 Schematic diagrams of the ends of some embodiments of electrode assemblies.

[0100] Figure 8A 、 Figure 8B 、 Figure 8C 、 Figure 8D and Figure 8E They are structural schematic diagrams of different embodiments of the second current collecting member.

[0101] Figure 9 Schematic diagram of the dimensions of some embodiments of the battery cell of the present application.

[0102] Figure 10 for Figure 9 A in the enlarged view.

[0103] Figure 11 A schematic diagram of the structure for electrically connecting two battery cells.

[0104] Figure 12 This is a structural diagram of the battery in this application in which the battery cell is installed in the box assembly through the support plate.

[0105] In the drawings, the drawings are not drawn to scale.

[0106] Marking Description:

[0107] 100. Battery Cell; 10. Housing; 1. Receptacle; 11. Opening; 12. First Through-Hole; 13. First End Wall; 14. Second End Wall; 15. Side Wall; 2. End Cap; 21. Pressure Relief Component; 22. Notch; 23. Recessed Portion; 3. Electrode Lead-Out Portion; 31. Main Body; 32. Base; 33. Position-Limiting Protrusion; 34. Recessed Portion; 341. First Recessed Portion; 342. Second Recessed Portion; 343. Third Through-Hole; 4. Electrode Assembly; 41 , electrode body; 42, first electrode tab; 43, second electrode tab; 44, second through hole; 45, first electrode piece; 45', first coating layer; 46, second electrode piece; 46', second coating layer; 47, separator; 5, first current collector; 6, second current collector; 6', hollow portion; 61, fourth through hole; 62, score line; 63, cutout; 7, insulating member; 8, cover plate; K, winding axis; z, first direction; y, second direction; x, third direction;

[0108] 200, battery; 201, housing assembly; 201A, housing portion; 201B, first cover; 201C, second cover; 202, busbar; 202A, first portion; 202B, second portion; 202C, third portion; 203, support plate; 203', third through hole;

[0109] 300. Vehicle; 301. Cockpit; 302. Floor. DETAILED DESCRIPTION

[0110] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, i.e., the present application is not limited to the described embodiments.

[0111] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0112] This application uses descriptions of directions or positional relationships such as "up", "down", "top", "bottom", "front", "back", "inside" and "outside" to facilitate the description of this application, and does not indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as limiting the scope of protection of this application.

[0113] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Perpendicular" does not strictly refer to perpendicularity, but rather to the tolerances allowed. "Parallel" does not strictly refer to parallelism, but rather to the tolerances allowed. The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application.

[0114] It should also be noted that, in the description of this application, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0115] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least some embodiments of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0116] Battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the present application does not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the present application does not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the present application does not limit this.

[0117] Current battery cells typically include a housing and an electrode assembly housed within the housing, which is filled with an electrolyte. The electrode assembly is primarily composed of a first and second electrode sheet with opposite polarities stacked or wound together, typically with a separator between them. The coated portions of the first and second electrode sheets constitute the main body of the electrode assembly, while the uncoated portions of the first and second electrode sheets each constitute a first and second tab. In a lithium-ion battery, the first electrode sheet may be a positive electrode sheet, comprising a positive current collector and a positive electrode coating layer disposed on either side of the positive current collector. The positive current collector may be made of, for example, aluminum, and the positive electrode coating may be made of, for example, lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The second electrode sheet may be a negative electrode sheet, comprising a negative current collector and a negative electrode coating layer disposed on either side of the negative current collector. The negative current collector may be made of, for example, copper, and the negative electrode coating may be made of, for example, graphite or silicon. The first and second tabs may be located together at one end of the main body or separately at either end. During the charge and discharge process of the battery cell, the positive electrode coating and the negative electrode coating react with the electrolyte, and the tabs connect to the electrode lead-out portions to form a current loop.

[0118] A pressure relief component refers to an element or component that is activated to release the internal pressure or temperature of a battery cell when the internal pressure or temperature reaches a predetermined threshold. The threshold design varies according to different design requirements. The threshold may depend on the material of one or more of the positive electrode plate, negative electrode plate, electrolyte and separator in the battery cell. The pressure relief component can take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and can specifically adopt a pressure-sensitive or temperature-sensitive element or structure, that is, when the internal pressure or temperature of the battery cell reaches a predetermined threshold, the pressure relief component performs an action or the weak structure provided in the pressure relief component is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released.

[0119] The term "activation" as used in this application refers to the action of the pressure relief component or its activation to a certain state, thereby allowing the internal pressure and temperature of the battery cell to be released. The action of the pressure relief component may include, but is not limited to: at least a portion of the pressure relief component rupturing, breaking, tearing, or opening, etc. When the pressure relief component is actuated, the internal emissions of the battery cell will be discharged outward from the actuated portion. In this way, the pressure and temperature of the battery cell can be released under controllable pressure or temperature, thereby avoiding potentially more serious accidents.

[0120] Among them, the emissions from battery cells mentioned here include but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of isolation membranes, high-temperature and high-pressure gases generated by the reaction (such as CH4, CO and other combustible gases), flames, etc.

[0121] Current batteries can exhibit poor safety issues during use. Research has found that safety is the most important performance requirement for automotive power batteries. To achieve longer driving ranges, the energy density of battery cells is increasing. This high energy density increases the instability of internal chemical materials, which in turn reduces the thermal runaway margin of the battery cells. Therefore, the key to ensuring the safety of the entire power battery system and vehicle is to prevent heat spread after thermal runaway of the battery cells.

[0122] In traditional cylindrical batteries, to simplify the battery cell structure, the positive and negative output electrodes are located at the same end as the pressure relief component. When a battery cell experiences thermal runaway, the material discharged from the pressure relief component will spray into the area where the busbar is located. The busbar is used to connect the positive and negative output electrodes of two battery cells to achieve the connection of multiple battery cells. Because the battery pack contains a large number of battery cells connected in series and parallel, and the voltage is usually above 100V, a large-scale short circuit or high-voltage spark may occur, causing the entire power battery system to catch fire or explode, causing damage to the vehicle, burns, and even casualties.

[0123] In response to the above defects, the inventors thought of setting the pressure relief component as far away from the positive output pole and the negative output pole as possible, so as to reduce the impact of high-temperature and high-pressure discharge on the manifold after thermal runaway of the battery cell occurs, thereby preventing thermal runaway of the entire power battery system.

[0124] Based on this improvement concept, the present application provides an improved battery cell. The battery cell comprises: a housing and an electrode assembly; wherein the housing is provided with an electrode lead-out portion and a pressure relief component, and the electrode lead-out portion and the pressure relief component are respectively provided at opposite ends of the housing along a first direction; the electrode assembly is disposed within the housing, and comprises an electrode body and first and second electrode tabs of opposite polarities, the first and second electrode tabs extending from the electrode body, and at least one of the first and second electrode tabs being electrically connected to the electrode lead-out portion.

[0125] The battery cells of the embodiments of the present application are suitable for use in batteries and electrical devices using the batteries.

[0126] Electrical devices may be mobile phones, portable devices, laptop computers, electric vehicles, electric cars, ships, spacecraft, electric toys and electric tools, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers.

[0127] like Figure 1As shown, the power-consuming device can be a vehicle 300, such as a new energy vehicle, which can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle; or it can be a drone or a ship. Vehicle 300 may include a cabin 301 and a vehicle floor 302, with battery 200 disposed between cabin 301 and vehicle floor 302. Battery 200 can be located at the bottom, front, or rear of vehicle 300 to provide power to the motor and other vehicle components.

[0128] like Figure 2 As shown, battery 200 includes a battery cell 100. In battery 200, there can be one or more battery cells 100. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, in parallel, or in a hybrid connection. Hybrid connection refers to multiple battery cells 100 being connected both in series and in parallel. Multiple battery cells 100 can be connected in series, in parallel, or in a hybrid connection to form a battery module, and the multiple battery modules can then be connected in series, in parallel, or in a hybrid connection to form a whole, which is then housed in a housing assembly 201. Alternatively, all battery cells 100 can be directly connected in series, in parallel, or in a hybrid connection, and then the whole formed by all battery cells 100 is housed in a housing assembly 201.

[0129] Figure 2 The battery 200 further includes a housing assembly 201. The housing assembly 201 is hollow and is used to accommodate one or more battery cells 100. Depending on the shape, quantity, combination, and other requirements of the battery cells 100 to be accommodated, the housing assembly 201 may also have different shapes and sizes. For example, the housing assembly 201 may include: a housing portion 201A, a first cover 201B, and a second cover 201C. The housing portion 201A has openings at both opposing ends. The first cover 201B and the second cover 201C are respectively used to close the openings at both ends of the housing portion 201A. For example, depending on the arrangement of the multiple battery cells 100, the housing portion 201A may have a rectangular cylindrical structure. To facilitate maintenance of the battery 200, the housing assembly 201 can be removably mounted on an electrical device.

[0130] For example, the battery cell 100 is cylindrical, and its axis is arranged along the first direction z. Multiple battery cells 100 can be arranged in an xoy plane perpendicular to the first direction z. Multiple battery cells 100 can be arranged in a rectangular array along the second direction y and the third direction x, and the second direction y is perpendicular to the third direction x.

[0131] Optionally, the structural member of the electrical device forms a space for accommodating the battery cell 100 , which functions as the box assembly 201 in the battery 200 . For example, when the battery cell 100 is used in the vehicle 300 , the vehicle frame forms a space for accommodating the battery cell 100 .

[0132] 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.

[0133] The present application provides a battery cell 100 , and the subsequent embodiments are described using a cylindrical battery cell 100 as an example. Figure 3 is a schematic diagram of the appearance of a battery cell 100, Figure 4 is an exploded view of a battery cell 100, Figure 5 is a cross-sectional view of a battery cell 100 .

[0134] In the above-mentioned improved battery cell 100, the electrode lead-out portion is defined as an output pole that at least partially protrudes from the outer wall of the shell 10. In order to focus on the embodiment in which the battery cell 100 outputs electrical energy through the electrode lead-out portion and the shell in the subsequent introduction, for the convenience of description, the two poles that output electrical energy are respectively defined as the first output pole and the second output pole.

[0135] In some embodiments, the battery cell 100 includes: a shell 10, an electrode assembly 4, a first output pole and a second output pole; wherein the electrode assembly 4 includes an electrode body 41 and a first pole tab 42 and a second pole tab 43 with opposite polarities, the first pole tab 42 and the second pole tab 43 are led out from the electrode body 41, the first output pole is electrically connected to the first pole tab 42, and the second output pole is electrically connected to the second pole tab 43, the shell 10 is used to accommodate the electrode assembly 4, and the shell 10 is provided with a pressure relief component 21, along the first direction z, the first output pole and the second output pole are arranged at the first end of the shell, and the pressure relief component 21 is arranged at the other end of the shell 10.

[0136] The housing 10 may be a thin-walled hollow structure for accommodating the electrode assembly 4. The housing 10 may be cylindrical, flat, rectangular, or in other shapes.

[0137] The first output pole and the second output pole are used to input or output electrical energy. The first pole ear 42 and the first output pole, as well as the second pole ear 43 and the second output pole can be electrically connected by welding, elastic contact, etc. The pole ears and the output poles can be directly connected or connected through a current collector.

[0138] The specific structure of the pressure relief component 21 has been described above. Taking a cylindrical battery cell 100 as an example, the first direction z is consistent with the central axis of the battery cell 100, and the first and second output poles and the pressure relief component 21 are respectively provided at opposite ends of the housing 10 along the first direction z.

[0139] The electrode assembly 4 is arranged in the housing 10. Figure 6 and Figure 7As shown, the electrode assembly 4 is formed by winding a first electrode sheet 45 and a second electrode sheet 46 of opposite polarity around a winding axis K. The winding axis K is aligned with the first direction z. A separator 47, such as a diaphragm, is typically provided between the first electrode sheet 45 and the second electrode sheet 46. For cylindrical battery cells 100, the wound electrode assembly 4 can be cylindrical; for rectangular battery cells 100, the wound electrode assembly 4 can be flat.

[0140] The first pole piece 45 includes a first current collector, which includes a first main body and a first pole tab 42. The first pole tab 42 protrudes outward from the end surface of the first main body along the winding direction K. A first coating layer 45' is provided on the side of the first main body. The first coating layer 45' can be provided on both sides of the first main body. For the innermost or outermost pole piece, the first coating layer 45' can be provided only on one side of the first main body. The first pole tab 42 can extend continuously along the length direction of the first pole piece 45 to form a continuous pole tab; or the continuous pole tab can be die-cut to form a serrated pole tab. For example, the first pole piece 45 is a positive electrode sheet, the first current collector can be made of aluminum, and the first coating layer 45' can include a first active material layer, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide.

[0141] The second pole piece 46 includes a second current collector, which includes a second main body and a second pole tab 43. The second pole tab 43 protrudes outward from the end surface of the second main body along the winding direction K. A second coating layer 46' is provided on the side of the second main body. The second coating layer 46' can be provided on both sides of the second main body. For the innermost or outermost pole piece, the second coating layer 46' can be provided only on one side of the second main body. The second pole tab 43 can extend continuously along the length of the second pole piece 46 to form a continuous pole tab; or the continuous pole tab can be die-cut to form a serrated pole tab. For example, the second pole piece 46 is a negative pole piece, the second current collector can be made of copper, and the second coating layer 46' can include a second active material layer, such as graphite or silicon. Alternatively, the first pole piece 45 can be a negative pole piece, and the second pole piece 46 can be a positive pole piece.

[0142] For the wound electrode assembly 4, the electrode assembly 4 includes an electrode body 41, a first pole tab 42 and a second pole tab 43. The first main body portion of the first pole piece 45 and the second main body portion of the second pole piece 46 form the electrode body 41. The first pole tab 42 and the second pole tab 43 are both led out from the electrode body 41. For example, the first pole tab 42 and the second pole tab 43 can be respectively led out from the two ends of the electrode body 41 along the first direction z, or can also be led out from the electrode body 41 along the first direction z toward one end of the electrode lead-out portion.

[0143] In this embodiment, the first output pole and the second output pole are arranged at one end of the shell 10, and the pressure relief component 21 is arranged at the other end of the shell 10. When thermal runaway occurs inside the battery cell 100, the active material will be ejected from the end where the pressure relief component 21 is located, away from the first output pole and the second output pole of the battery cell 100, and thus away from the busbar used to electrically connect multiple battery cells 100. This can reduce the impact on the electrical connection of the battery cell 100 when thermal runaway occurs, prevent a large-scale short circuit or high-voltage ignition in the battery 200, so as to avoid causing thermal runaway of the entire power battery system, or even cause fire and explosion, thereby improving the safety of the power battery system. Secondly, by arranging the pressure relief component 21 and the output pole at both ends of the shell 10, there is a larger space for the pressure relief component 21 to be arranged, which can improve the current capacity of the output pole, and also facilitate the processing of the pressure relief component 21 and more accurately control its opening pressure. It also prevents welding stress from affecting the opening pressure of the pressure relief component 21 when welding the busbar. In addition, the first output electrode and the second output electrode are arranged at the same end of the housing 10 , which can facilitate the installation and connection of the busbar when the plurality of battery cells 100 are electrically connected.

[0144] In some embodiments, as Figure 5 As shown, the shell 10 includes 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 to each other along the first direction z. The first end wall 13 is provided with a first through hole 12. The electrode lead-out portion 3 of the battery cell 10 is installed in the first through hole 12 and is insulated from the first end wall 13. The second end wall 14 is provided with a pressure relief component 21; the electrode lead-out portion 3 is the first output pole, and the first end wall 13 is the second output pole.

[0145] For example, the housing 10 is cylindrical, and the sidewall 15 is open at both ends. The first end wall 13 and the second end wall 14 are the two ends of the cylinder, respectively, and are used to close the ends of the sidewall 15. The electrode lead portion 3 is 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 adhesive is applied therebetween.

[0146] The electrode lead portion 3 is an output electrode protruding from the housing 10, such as an electrode terminal, so as to facilitate electrical connection between different battery cells 100 through a busbar. The electrode terminal can be designed as a pole, which can be cylindrical, square, or other cylindrical structures.

[0147] Optionally, the electrode lead-out portion 3 serves as the positive output electrode, and the first end wall 13 serves as the negative output electrode. Because the first tab 42 and the first current collector 5 are made of aluminum, the electrode lead-out portion 3 can be made of aluminum accordingly, eliminating the need for a composite material electrode lead-out portion. Alternatively, the electrode lead-out portion 3 serves as the negative output electrode, and the first end wall 13 serves as the positive output electrode.

[0148] Optionally, the polarity of the first end wall 13 is the same as the polarity of the outermost electrode sheet of the first electrode sheet 45 and the second electrode sheet 46. The side wall 15 is connected to the first end wall 13 with the same polarity. When metal particles are present between the electrode assembly 4 and the side wall 15, the particles pierce the outermost separator 47 of the electrode assembly 4 and then the separator 47, thereby establishing electrical connection between the outermost electrode sheet and the side wall 15. If the polarity of the outermost electrode sheet is the same as that of the side wall 15, a short circuit in the battery cell 100 can be avoided, thereby improving the safety performance of the battery 200.

[0149] In this embodiment, the electrode lead-out portion 3 and the first end wall 13 are arranged at the same end of the shell 10, and the pressure relief component 21 is arranged at the other end of the shell 10. When thermal runaway occurs inside the battery cell 100, the active material will be ejected from the end where the pressure relief component 21 is located, away from the electrode lead-out portion 3 and the first end wall 13 of the battery cell 100, and thus away from the busbar used to electrically connect multiple battery cells 100, which can reduce the impact on the electrical connection of the battery cell 100 when thermal runaway occurs.

[0150] Moreover, by using 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 of difficult layout due to the small end area of the battery cell 100 and simplifying the structure of the battery cell 100.

[0151] In some embodiments, as Figure 5 As shown, the housing 10 includes: a receiving portion 1 and an end cover 2 . The receiving portion 1 has an opening 11 . The end cover 2 is used to cover the opening 11 . The receiving portion 1 is formed by a first end wall 13 and a side wall 15 . The end cover 2 is a second end wall 14 .

[0152] Among them, the end cover 2 and the accommodating part 1 are independent components. The end cover 2 can be made of metal materials such as steel or alloy materials. After the electrode assembly 4 is installed, the end cover 2 can be fixed to the accommodating part 1 by welding, bonding or fastener connection, and the end cover 2 and the accommodating part 1 need to be sealed to avoid air leakage.

[0153] The first end wall 13 and the side wall 15 can be formed integrally, which facilitates processing. Furthermore, when thermal runaway occurs within the battery cell 100, causing pressure to increase, the connection between the first end wall 13 and the side wall 15 has a strong pressure resistance, and pressure relief is preferentially provided by the pressure relief component 21 to prevent rupture at the connection between the first end wall 13 and the side wall 15, thereby improving pressure relief reliability. Alternatively, the first end wall 13 and the side wall 15 are integrally connected by welding or other means.

[0154] For example, for a cylindrical battery cell 100 , the receiving portion 1 may be a cylindrical structure with an opening 11 at one end, and the end cover 2 may be a disc-shaped structure for covering the opening 11 , with the end of the receiving portion 1 away from the opening 11 being closed.

[0155] For example, the pressure relief component 21 is integrally formed with the end cap 2, that is, a reduced thickness portion is provided on the end cap 2, and the area enclosed by the reduced thickness portion constitutes the pressure relief component 21. For example, the reduced thickness portion may be a notch 22, which may be provided on the inner and / or outer wall of the end cap 2. When the pressure relief component 21 is opened, the pressure relief component 21 is destroyed at the reduced thickness portion, thereby forming an opening or channel for internal pressure or temperature to be released.

[0156] A first through hole 12 may be provided at one end of the accommodating portion 1 away from the end cover 2, and the electrode lead-out portion 3 may be installed in the first through hole 12 from the inner cavity of the accommodating portion 1. An insulating member 7 is provided between the electrode lead-out portion 3 and the accommodating portion 1 to achieve insulation between the electrode lead-out portion 3 and the accommodating portion 1. The electrode lead-out portion 3 is covered by a cover plate 8.

[0157] In this embodiment, the pressure relief component 21 is arranged on the end cover 2 which is independent of the accommodating portion 1, which can reduce the process difficulty of setting the pressure relief component 21, and is more convenient to set the pressure relief component 21 integrally on the end cover 2. In addition, it is easier to control the dimensional accuracy of the weak area of the pressure relief component 21 during processing, so as to improve the setting accuracy of the opening pressure of the pressure relief component 21. When thermal runaway occurs in the battery cell 100, the pressure relief component 21 can be reliably opened, thereby improving the safety of the operation of the battery cell 100.

[0158] Moreover, since the first output pole and the second output pole are both arranged on the first end wall 13 integrally provided with the side wall 15, and are not arranged on the end cover 2, the pulling of the busbar on the connection between the end cover 2 and the side wall 15 is reduced, and fatigue is prevented at the connection, thereby reducing the influence of the busbar on the pressure relief component 21. To a certain extent, the damage to the pressure relief component 21 during normal use of the battery cell 100 is reduced, and premature pressure relief is prevented.

[0159] In some embodiments, the housing 10 includes: a receiving portion 1 and an end cover 2 , the receiving portion 1 has an opening 11 , the end cover 2 is used to cover the opening 11 , the receiving portion 1 is formed by a second end wall 14 and a side wall 15 , and the end cover 2 is a first end wall 13 .

[0160] Optionally, the second end wall 14 and the side wall 15 can be formed integrally, which facilitates processing. Furthermore, a pressure relief component 21 is provided on the second end wall 14. This reduces stress at the connection between the second end wall 14 and the side wall 15, thereby reducing the tensile stress applied to the pressure relief component 21 and preventing damage to the precision of the pressure relief component 21. When thermal runaway occurs within the battery cell 100, the pressure relief component 21 can precisely control the opening pressure, thereby improving the reliability of pressure relief during thermal runaway. Optionally, the second end wall 14 and the side wall 15 are integrally connected by welding or other means.

[0161] In this embodiment, the electrode lead-out portion 3 is provided on the end cover 2 which is independent of the accommodating portion 1 , so that the electrode lead-out portion 3 can be conveniently mounted on the end cover 2 .

[0162] Optionally, both ends of the accommodating portion 1 are provided with openings 11 , and the openings 11 at both ends are covered by end covers 2 , and the electrode lead-out portion 3 and the pressure relief component 21 are respectively provided on the two end covers 2 .

[0163] In some embodiments, as Figure 5 As shown, the first pole tab 42 is led out from the electrode body 41 along the first direction z facing the electrode lead-out portion 3, and the second pole tab 43 is led out from the electrode body 41 along the first direction z away from the electrode lead-out portion 3. The first pole tab 42 is electrically connected to the electrode lead-out portion 3, and the second pole tab 43 is electrically connected to the first end wall 13.

[0164] The first electrode tab 42 and the second electrode tab 43 are respectively led out from the two ends of the electrode body 41 along the first direction z. The first electrode tab 42 is close to the electrode lead-out portion 3 and can be directly connected or electrically connected through a current collector. The second electrode tab 43 is far away from the first end wall 13 and can be electrically connected through the side wall 15 of the shell 10. On this basis, it can also be assisted by the current collector and / or the second end wall 14.

[0165] In this embodiment, the first electrode tab 42 and the second electrode tab 43 are respectively led out from both ends of the electrode body 41 , which can improve the current carrying capacity and easily ensure the insulation reliability between the first electrode tab 42 and the second electrode tab 43 , thereby improving the working performance of the battery cell 100 .

[0166] In some embodiments, the battery cell 100 further includes a first current collector 5 and a second current collector 6 . The first electrode tab 42 is electrically connected to the electrode lead portion 3 through the first current collector 5 , and the second electrode tab 43 is electrically connected to the first end wall 13 through the second current collector 6 .

[0167] Among them, Figure 5As shown, the first electrode tab 42 can be fixed to the first current collector 5 by welding. After the electrode assembly 4 and the first current collector 5 are placed together in the accommodating portion 1, the electrode lead portion 3 is welded to the first current collector 5 from the outside of the first end cap 13. Alternatively, the first electrode tab 42 and the electrode lead portion 3 can be directly connected.

[0168] The second electrode tab 43 is far away from the first end wall 13 and can be electrically connected to the side wall 15 of the shell 10. The second electrode tab 43 can be directly connected to the side wall 15, or the second electrode tab 43 can be electrically connected to the side wall 15 through the second current collecting member 6. The specific implementation method will be given later.

[0169] In this embodiment, the first pole tab 42 is electrically connected to the electrode lead-out portion 3 through the first current collecting member 5, and the second pole tab 43 is electrically connected to the first end wall 13 through the second current collecting member 6, which can facilitate welding with the pole tabs, thereby improving the reliability of the electrical connection between the first pole tab 42 and the electrode lead-out portion 3, as well as the reliability of the electrical connection between the second pole tab 43 and the first end wall 13.

[0170] Three implementations of electrically connecting the second electrode tab 43 to the side wall 15 via the second current collecting member 6 are described below.

[0171] In a first implementation, the second current collecting member 6 contacts the side wall 15 to achieve electronic conduction between the second electrode tab 43 and the first end wall 13 .

[0172] The electrical energy transmitted by the second electrode tab 43 is directly transferred to the side wall 15 of the accommodating portion 1 through the second current collecting member 6. The side wall 15 is integrally formed with or electrically connected to the first end cover 13, thereby transmitting the electrical energy to the first end wall 13. The second current collecting member 6 and the side wall 15 can achieve electronic conduction through tight contact, or the second current collecting member 6 and the side wall 15 can be welded.

[0173] This embodiment can reduce the number of steps for the second electrode tab 43 to transmit electrical energy to the first end wall 13 , thereby improving the reliability of electrical energy transmission.

[0174] In a second implementation, the shell 10 includes: a accommodating portion 1 and an end cover 2, the accommodating 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 achieve electronic conduction between the second electrode ear 43 and the first end wall 13.

[0175] The second current collector 6 does not contact the side wall of the housing portion 1, and the end cap 2 is connected to the second current collector 6. The electrical energy transmitted by the second electrode tab 43 is transferred to the end cap 2 via the second current collector 6. The end cap 2 and the side wall 15 can be connected by welding or other means. Therefore, the electrical energy is transferred from the end cap 2 to the side wall 15 of the housing portion 1, thereby achieving an electrical connection between the second electrode tab 43 and the first end wall 13. The second current collector 6 and the end cap 2 can achieve electronic conduction through tight contact, or the second current collector 6 and the end cap 2 can be welded from the side of the end cap 2 away from the electrode assembly 4.

[0176] Optionally, the end cap 2 and the second current collecting member 6 can be connected by welding. In order to allow the gas to pass through the second current collecting member 6 and act on the pressure relief member 21 when the battery cell 100 experiences thermal runaway, there is a preset distance between the end cap 2 and the second current collecting member 6 in the first direction z. In order to achieve welding of the end cap 2 and the second current collecting member 6, as shown in FIG. Figure 5 As shown, the end cap 2 has a recessed portion 23 that protrudes as a whole toward the electrode assembly 4. The recessed portion 23 abuts the second current collecting member 6 and is located radially outward from the pressure relief member 21. The recessed portion 23 and the second current collecting member 6 can be welded from the outside of the end cap 2. For example, the recessed portion 23 can be an integral annular structure coaxially disposed outside the pressure relief member 21 to achieve a larger welding area and improve electrical connection reliability; alternatively, at least one recessed portion 23 can be circumferentially disposed around the outer periphery of the pressure relief member 21.

[0177] Optionally, the pressure relief component 21 may be recessed inward by a preset distance relative to the outermost wall of the end cover 2 to prevent the battery cell 100 from exerting additional force on the pressure relief component 21 when the end cover 2 is placed downward, thereby protecting the pressure relief component 21.

[0178] This embodiment electrically connects the second electrode tab 43 to the end cap 2. For example, when welding is used to achieve the electrical connection, the end cap 2 has a relatively flat welding surface, which facilitates welding and provides a better welding effect, thereby improving the reliability of the electrical connection between the second electrode tab 43 and the first end cap 13.

[0179] In a third implementation, the shell 10 includes: a accommodating portion 1 and an end cover 2, the accommodating 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 achieve electronic conduction between the second pole ear 43 and the first end wall 13.

[0180] The second current collecting member 6 is in contact with the side wall 15 of the accommodating portion 1 and is electrically connected to the end cover 2 . The electrical energy transmitted by the second electrode tab 43 can be transferred to the first end cover 13 through the above two conductive paths at the same time.

[0181] This embodiment allows the electric energy transmitted by the second electrode tab 43 to be transferred to the first end cover 13 through two conductive paths. When a virtual connection occurs in one of the conductive paths, the electric energy can continue to be transmitted through the other conductive path, thereby improving the reliability of electric energy transmission.

[0182] In some embodiments, the housing 10 includes a second end wall 14 , and the pressure relief component 21 is located in a central area of the second end wall 14 .

[0183] Among them, 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 can reach the pressure relief component 21 along the second through hole 44 and effectively act on the pressure relief component 21 to enable the pressure relief component 21 to be reliably opened.

[0184] In this embodiment, the pressure relief component 21 is arranged in the central area of the end cover 2. When thermal runaway occurs in the battery cell 100, the internal high-temperature and high-pressure airflow has a shorter airflow path regardless of the direction from which it reaches the pressure relief component 21, so that the pressure relief component 21 opens in time, thereby improving the reliability and safety of the battery cell 100.

[0185] In some embodiments, as Figures 8A to 8E As shown, along the first direction z, the second current collecting member 6 is located between the pressure relief component 21 and the second electrode tab 43, and a hollow portion 6' is provided on the second current collecting member 6. The hollow portion 6' is used to conduct gas between the space on one side of the second current collecting member 6 facing the second electrode tab 43 and the space on the other side facing the pressure relief component 21.

[0186] The shape and size of the hollow portion 6' must ensure the strength of the second current collector 6 while allowing the internal gas to quickly and smoothly reach the pressure relief component 21 in the event of thermal runaway of the battery cell 100. A second through hole 44 extending in the first direction z is provided at the center of the electrode assembly 4. In the event of thermal runaway of the battery cell 100, most of the high-temperature, high-pressure gas flow inside can flow through the second through hole 44 and through the hollow portion 6' to the pressure relief component 21, allowing it to reliably open.

[0187] This embodiment takes into account that the electrode lead-out portion and the pressure relief component 21 are disposed at opposite ends of the housing 10. By providing a hollow portion 6' on the second current collector 6, when thermal runaway occurs in any area inside the battery cell 100, high-temperature and high-pressure gas can smoothly pass through the hollow portion 6' to reach the pressure relief component 21, so as to be promptly discharged outward through the pressure relief component 21, thereby improving the safety of the battery cell 100 when thermal runaway occurs.

[0188] In some embodiments, as Figures 8A to 8EThe hollow portion 6' includes at least one fourth through hole 61, wherein one fourth through hole 61 is located at the center of the second current collecting member 6. For example, the fourth through hole 61 can be a circular hole, an elliptical hole, or a polygonal hole.

[0189] Normally, the gas in the electrode assembly 4 is discharged to the outside of the electrode assembly 4 through the electrode ear side. By setting a fourth through hole 61 in the center of the second current collecting member 6, the gas discharged from each area of the second electrode ear 43 can reach the fourth through hole 61 relatively promptly, thereby smoothly reaching the pressure relief component 21.

[0190] In some embodiments, as Figure 8C As shown, a plurality of fourth through holes 61 are provided, and the remaining fourth through holes 61 are distributed around the fourth through hole 61 at the center. For example, the remaining fourth through holes 61 can be evenly distributed around the fourth through hole 61 at the center, or the remaining fourth through holes 61 are distributed in the area where the second electrode tab 43 is provided.

[0191] This embodiment can reasonably increase the exhaust area and, to a certain extent, solve the problem of untimely exhaust caused by blockage at the center of the second collecting member 6 .

[0192] In some embodiments, as Figure 8B and Figure 8E As shown, the hollow portion 6' further includes a plurality of cutouts 63 that extend through the second current collecting member 6 along the first direction z and surround the fourth through-hole 61. For example, the cutouts 63 are elongated and have a certain width. The cutouts 63 may extend along a straight line, such as along the radial direction of the circular second current collecting member 6; or the cutouts 63 may extend along a curved line, such as along the circumference of the circular second current collecting member 6.

[0193] This embodiment provides multiple cutouts 63 in addition to the fourth through hole 61 to assist in venting. In the event of thermal runaway of the battery cell 100, air can simultaneously pass through the fourth through hole 61 and the multiple cutouts 63 to reach the pressure relief component 21. Furthermore, the elongated shape of the cutouts 63 allows for venting without weakening the second current collecting member 6, and also facilitates fabrication.

[0194] In some embodiments, one end of the cutout 63 is communicated with the fourth through hole 61 and extends in a direction away from the fourth through hole 61 .

[0195] For example, the second current collecting member 6 is circular, one end of the cutout 63 is connected to the fourth through hole 61, and the cutout 63 extends radially of the second current collecting member 6 away from the fourth through hole 61. The multiple cutouts 63 can be evenly arranged along the circumference. Alternatively, one end of the cutout 63 is not connected to the fourth through hole 61, and a predetermined distance is maintained therebetween.

[0196] This embodiment can achieve reliable exhaust from the center to the periphery of the second current collecting member 6 . When thermal runaway occurs in the battery cell 100 , the air flow can flow to the pressure relief component 21 more smoothly and promptly.

[0197] In some embodiments, as Figure 8A and Figure 8D As shown, the hollow portion 6 ′ further includes a score line 62 , and the score line 62 passes through the second current collecting member 6 along the first direction z.

[0198] For example, the score line 62 is linear. While theoretically there is no gap between the two sidewalls forming the score line 62 in the same plane, a slight gap may exist in practice. Under the action of air pressure, the second current collecting member 6 may deform at the score line 62, forming a gap between the two sidewalls of the score line 62. The score line 62 may extend continuously or intermittently as a dashed line. The score line 62 may extend along a straight line, such as along the radial direction of the circular second current collecting member 6, or along a curved line, such as along the circumference of the circular second current collecting member 6.

[0199] In this embodiment, multiple score lines 62 are provided in addition to the fourth through hole 61 to assist in venting the gas from the fourth through hole 61. In the event of thermal runaway of the battery cell 100, air can simultaneously pass through the fourth through hole 61 and the multiple score lines 62 to reach the pressure relief component 21. Furthermore, the score lines 62 minimize any weakening of the second current collecting member 6 while achieving venting.

[0200] In some embodiments, a plurality of score lines 62 are provided, and one end of the score line 62 is connected to the fourth through hole 61 and extends in a direction away from the fourth through hole 61 .

[0201] For example, the second current collecting member 6 is circular, one end of the score line 62 is connected to the fourth through hole 61, and extends in a radial direction of the second current collecting member 6 in a direction away from the fourth through hole 61. The multiple score lines 62 can be evenly arranged along the circumference. Optionally, one end of the cutout 63 is not connected to the fourth through hole 61 and is at a predetermined distance.

[0202] This embodiment can achieve reliable exhaust from the center to the periphery of the second current collecting member 6 . When thermal runaway occurs in the battery cell 100 , the air flow can flow to the pressure relief component 21 more smoothly and promptly.

[0203] Below Figures 8A to 8E The hollow portions 6' provided on the second current collecting member 6 are described below.

[0204] like Figure 8AAs shown, the hollow portion 6' may include a fourth through-hole 61 and a score line 62 provided on the second current collecting member 6. For example, the second current collecting member 6 may be circular, and the fourth through-hole 61 may be located at the center of the second current collecting member 6. The score line 62 extends through the second current collecting member 6, with one end of the score line 62 communicating with the fourth through-hole 61 and the other end extending radially outward. For example, the score line 62 may be provided continuously or intermittently, or multiple score lines 62 may be provided in a radial pattern. For example, four score lines 62 may be provided to form a cross.

[0205] This embodiment can achieve reliable exhaust from the center to the periphery of the second current collecting member 6 and minimize the weakening of the strength of the second current collecting member 6 caused by the hollow portion 6 ′. The linear score lines 62 are easy to process.

[0206] like Figure 8B As shown, the hollow portion 6' may include a fourth through hole 61 and a notch 63 provided on the second current collecting member 6. For example, the second current collecting member 6 may be circular, the fourth through hole 61 may be located at the center of the second current collecting member 6, and the notch 63 may pass through the second current collecting member 6 and extend radially. Multiple notches 63 may be provided in a radial pattern, for example, four notches 63 may be provided to form a cross.

[0207] This embodiment can achieve reliable exhaust from the center to the periphery of the second current collecting member 6, can reduce the weakening of the strength of the second current collecting member 6 on the basis of achieving exhaust, and the linear cut 63 is also easy to process.

[0208] like Figure 8C As shown, the hollow portion 6' may include at least one fourth through hole 61 provided on the second current collecting member 6. For example, one fourth through hole 61 may be provided, and for a circular second current collecting member 6, the fourth through hole 61 may be provided at the center position of the second current collecting member 6; or a plurality of fourth through holes 61 may be provided, for example, one of the fourth through holes 61 is located at the center position of the second current collecting member 6, and the remaining fourth through holes 61 are distributed around the central fourth through hole 61.

[0209] This embodiment can reasonably increase the exhaust area and, to a certain extent, solve the problem of delayed exhaust caused by blockage at the center of the second collecting member 6 . Moreover, the hollow portion 6 ′ is easy to process.

[0210] like Figure 8D As shown, Figure 8A The difference is that the score line 62 is curved, for example, the score line 62 is an arc or a circle. The score line 62 can be concentric with the fourth through hole 61. This embodiment can have a better exhaust effect in the circumferential direction of the second collector 6.

[0211] like Figure 8E As shown, Figure 8BThe difference is that the cutout 63 is curved, for example, arc-shaped or circular, and can be concentric with the fourth through hole 61. For example, the cutout 63 can be continuous, or it can be divided into multiple segments, with the multiple segments of cutouts 63 spaced apart around the periphery of the fourth through hole 61. This embodiment can achieve a good exhaust effect in the circumferential direction of the second current collecting member 6, and the cutout 63 is easy to process.

[0212] In some embodiments, the first electrode tab 42 and the second electrode tab 43 are both extended from one end of the electrode body 41 facing the electrode lead portion 3 along the first direction z. The first electrode tab 42 is electrically connected to the electrode lead portion 3 , and the second electrode tab 43 is electrically connected to the first end wall 13 .

[0213] The first electrode tab 42 and the second electrode tab 43 are led out from the same end of the electrode body 41 along the first direction z. The distance between the first electrode tab 42 and the electrode lead portion 3 and the distance between the second electrode tab 43 and the first end wall 13 are both close, and they can be directly connected or electrically connected through the current collector.

[0214] In this embodiment, the first electrode tab 42 and the second electrode tab 43 are both led out from one end of the electrode body 41 facing the electrode lead-out portion 3, which facilitates electrical connection. Moreover, the first electrode tab 42 and the second electrode tab 43 only need to occupy space on a single side of the electrode body 41, which can shorten the height of the battery cell 100 and is conducive to improving the energy density of the battery cell 100.

[0215] In some embodiments, the battery cell 100 also includes a first current collector 5 and a second current collector 6, the first pole tab 42 is electrically connected to the electrode lead-out portion 3 through the first current collector 5, and the second pole tab 43 is electrically connected to the first end wall 13 through the second current collector 6; the electrode lead-out portion 3 includes a base 31 and a main body 32, the base 31 is located between the first end wall 13 and the first current collector 5, and is used to limit the movement of the electrode lead-out portion 3 along the first direction z toward the direction away from the interior of the shell 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 32 is located in the first through hole 12.

[0216] The outer diameter of the base 31 is generally larger than that of the first through-hole 12. The base 31 is used for electrical connection to the first current collector 5, and a gap is formed between the base 31 and the first end wall 13. At least a portion of the main body 32 is located within the first through-hole 12, with a gap between the main body 32 and the inner wall of the first through-hole 12. For example, the electrode lead 3 may be generally in the shape of a stepped cylinder. The main body 32 is inserted into the first through-hole 12, and the diameter of the main body 32 is smaller than the inner diameter of the first through-hole 12 to facilitate the installation of the insulating member 7.

[0217] The insulating member 7 may be C-shaped, with the sidewall portion of the first through hole 12 embedded in the opening of the C-shaped insulating member 7, so that the insulating member 7 surrounds the inner sidewall of the first through hole 12 and the inner and outer surfaces of the first end wall 13 adjacent to the first through hole 12. The portion of the insulating member 7 located on the first end wall 13 facing the first current collector 5 is in contact with the inner surface of the first end wall 13.

[0218] The electrode lead portion 3 of this embodiment can be prevented from falling out of the first through hole 12 by the limiting effect of the base 31, thereby improving the reliability of the electrical connection between the electrode lead portion 3 and the first current collector 5. The insulating member 7 can also achieve insulation between the electrode lead portion 3 and the first end wall 13.

[0219] In some embodiments, as Figure 9 As shown, the maximum thickness t1 of the base 31 of the electrode lead-out portion 3 has a size range of: 0.6mm≤t1≤1.2mm; and / or the maximum thickness t2 of the first current collecting member 5 has a size range of: 0.3mm≤t2≤0.7mm; and / or the maximum thickness t3 of the second current collecting member 6 has a size range of: 0.3mm≤t3≤0.7mm.

[0220] In order to achieve better effects, 0.8 mm ≤ t1 ≤ 1 mm, 0.4 mm ≤ t2 ≤ 0.6 mm, and / or 0.4 mm ≤ t3 ≤ 0.6 mm.

[0221] 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 to prevent air from being ejected through the installation position of the electrode lead-out portion 3 when thermal runaway occurs in the battery cell 100 .

[0222] This embodiment ensures that gas is discharged through the pressure relief component 21 when thermal runaway occurs in the battery cell 100 by setting appropriate thicknesses for the base 31 of the electrode lead-out portion 3, the first current collecting member 5, and the second current collecting member 6, thereby preventing gas from being ejected from the side where the electrode lead-out portion 3 and the first end wall 13 are set, thereby improving the safety of the battery cell 100.

[0223] In some embodiments, the electrode lead-out portion 3 also includes a limiting protrusion 33, and the base 31 and the limiting protrusion 33 are both connected to and protrude from the outer peripheral wall of the main body 32. The limiting protrusion 33 and the base 31 are respectively located on the outer side and the inner side of the first end wall 13 along the first direction z, and are used to clamp a portion of the first end wall 13.

[0224] The base 31 and the limiting protrusion 33 are both connected to the outer peripheral wall of the main body 32. A gap is also provided between the limiting protrusion 33 and the outer surface of the first end wall 13, for disposing the insulating member 7 between the limiting protrusion 33 and the first end wall 13. For example, the electrode lead portion 3 is generally in the shape of a stepped cylinder. The diameters of the base 31 and the limiting protrusion 33 are both larger than the diameter of the main body 32, the diameter of the limiting 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.

[0225] A groove is formed on the outer wall of the electrode lead-out portion 3 between the base 31, the main body 32, and the limiting protrusion 33. The insulating member 7 can be C-shaped and embedded in the groove, and the opening of the C-shaped insulating member 7 is aligned with the opening direction of the groove. The side wall portion of the first through hole 12 is embedded in the opening of the C-shaped insulating member 7, so that the first cantilever of the insulating member 7 is located between the first end wall 13 and the base 31, and the first cantilever is arranged beyond the base 31. The second cantilever is located between the first end wall 13 and the limiting protrusion 33, and the second cantilever is arranged beyond the limiting protrusion 33. The side wall portion connecting the first cantilever and the second cantilever is located between the inner wall of the first through hole 12 and the main body 32. The outer ends of the two cantilevered arms of the insulating member 7 are respectively. This insulating member 7 can reliably achieve insulation between the electrode lead-out portion 3 and the first end wall 13, and prevent high-pressure gas from escaping from the gap between the first end wall 13 and the electrode lead-out portion 3 in the event of thermal runaway.

[0226] In this embodiment, the limiting protrusion 33 and the base 31 clamp a portion of the first end wall 13 , so that the electrode lead-out portion 3 can be more stably and reliably installed on the first end wall 13 .

[0227] In some embodiments, the main body 32 is provided with a recess 34, the bottom wall of the recess 34 is connected to the first current collecting member 5 to achieve electronic conduction between the electrode lead portion 3 and the first electrode tab 42, and the opening of the recess 34 is provided on the side of the main body 32 facing and / or away from the interior of the shell 10.

[0228] Among them, Figure 5 As shown, the opening of the recess 34 is located on the side of the main body 32 facing away from the interior of the housing 10. This allows the bottom wall of the recess 34 to be closer to the first current collector 5, facilitating electrical connection between the two. The first current collector 5 can be designed as a flat plate to reduce processing difficulty. The recess 34 is stepped and includes a first recess 341 and a second recess 342. The second recess 342 is located on the bottom wall of the first recess 341. The inner diameter of the second recess 342 is smaller than that of the first recess 341. The bottom wall of the second recess 342 is provided with a third through-hole 343 for injecting electrolyte into the housing 10. The cover plate 8 is embedded in the first recess 341 to seal the opening of the recess 34, thereby sealing the third through-hole 343.

[0229] In this embodiment, by providing the recess 34 on the main body 32 , the thickness of the region where the main body 32 is electrically connected to the first current collector 5 can be reduced, thereby improving the reliability of the electrical connection between the main body 32 and the first current collector 5 .

[0230] In some embodiments, the bottom wall of the recess 34 is laser welded to a side of the first current collecting member 5 facing away from the interior of the housing 10 from the main body 32 .

[0231] In this embodiment, by providing the recess 34, the thickness of the welding area between the main body 32 and the first current collector 5 is reduced. The main body 32 and the first current collector 5 can be conveniently welded from the outside of the electrode lead-out portion 3, thereby improving welding reliability. In addition, the metal ions generated by welding will not enter the shell 10, thereby improving the reliability of the battery cell 100.

[0232] In some embodiments, as Figure 9 As shown, the housing 10 is cylindrical, the pressure relief component 21 is provided at the center of the second end wall 14 and is circular, and the pressure relief component 21 has a pressure relief area. The diameter φ1 of the pressure relief area and the diameter φ of the housing 10 satisfy the following relationship:

[0233] The pressure relief component 21 is formed by providing a reduced thickness portion, for example, a notch 22. The area enclosed by the notch 22 constitutes the pressure relief zone. For ease of measurement, the diameter φ1 of the pressure relief zone can be represented by the diameter of the circle enclosed by the inner walls of the notch 22. In one structural form, the pressure relief component 21 is integrally formed on the second end wall 14, that is, the notch 22 is directly machined on the second end wall 14. In another structural form, the pressure relief component 21 is an independent part, and its outer wall is connected to the second end wall 14 by welding. The outer wall diameter of the pressure relief component 21 is larger than the maximum diameter of the notch 22. In this case, the diameter of the pressure relief zone is still the diameter of the circle enclosed by the inner walls of the notch 22.

[0234] When φ1 is less than 0.35*φ, the pressure relief zone of the pressure relief component 21 is not sufficiently opened when thermal runaway occurs near the electrode lead-out portion 3 in the battery cell 100, and the rate of heat discharge from the battery cell 100 is too slow, causing damage to the electrode lead-out portion 3 or the shell 10 or even heat leakage. When φ1 is greater than 0.85*φ, the pressure relief zone of the pressure relief component 21 occupies a large proportion of the area on the second end wall 14, resulting in insufficient strength of the second end wall 14. During the use of the battery cell 100, the gas pressure generated internally causes the pressure relief component 21 to open, causing leakage and abnormal electrical connection.

[0235] The following table 1 illustrates the impact of the diameter design of the pressure relief component 21 on the safety of the battery cell 100. The units of the dimensional parameters in the following table are all mm.

[0236] Table 1 Impact of the pressure relief area diameter design of the pressure relief component 21 on the safety of the battery cell 100

[0237]

[0238] In Table 1, for Example 1, The pressure relief area of the pressure relief component 21 accounts for a relatively small area relative to the area of the end of the shell 10. When a needle puncture failure test is carried out on the side where the electrode lead-out portion 3 and the first end wall 13 are located, the battery cell 100 short-circuits and internal thermal runaway occurs. Since the weak parts of the pressure relief component 21 are small, such as the short notch, the difficulty of opening is increased. Even after the pressure relief component 21 is opened, the high-temperature and high-pressure gas is discharged from the pressure relief component 21 at a slow speed. The instantaneous high pressure will cause the gas to be discharged toward one side of the electrode lead-out portion, causing damage to the electrode lead-out portion, thereby causing the electrical connection of the battery cell 100 to fail. However, since the pressure relief area of the pressure relief component 21 is relatively small, the strength of the end cover 2 on which the pressure relief component 21 is provided can be ensured, and leakage is not likely to occur during use. In each table, the side where the electrode lead-out portion 3 and the first end wall 13 are located is referred to as the "electrical connection side."

[0239] For Examples 2-5, The pressure relief area of the pressure relief component 21 accounts for a relatively large area relative to the end of the housing 10. When a needle puncture failure test is conducted near the electrode lead-out portion 3 and the first end wall 13, if a short circuit occurs in the battery cell 100 and thermal runaway occurs internally, the larger weak point of the pressure relief component 21, such as the longer notch, reduces the difficulty of opening. Moreover, after the pressure relief component 21 is opened, high-temperature and high-pressure gas can be quickly discharged from the pressure relief component 21, preventing gas from being discharged from the side facing the electrode lead-out portion 3, thereby avoiding damage to the electrode lead-out portion 3 and ensuring effective electrical connection of the battery cell 100. However, in Example 6, the larger area of the pressure relief component 21 reduces the strength of the end cap 2 on which the pressure relief component 21 is provided, resulting in leakage during use.

[0240] This embodiment sets a proportional relationship between the diameter of the pressure relief area of the pressure relief component 21 and the diameter of the shell 10. When thermal runaway occurs in the battery cell 100, it can ensure that the pressure relief component 21 has a sufficient opening area to quickly discharge heat from the battery cell 100, thereby preventing damage to the electrode lead-out portion or the shell 10 or even heat leakage. Moreover, on the basis of ensuring that the pressure relief component 21 can be reliably opened, the strength of the end of the shell 10 where the pressure relief component 21 is set can be improved to prevent the internal air pressure of the battery cell 100 from causing the pressure relief component 21 to open during normal use, resulting in leakage and abnormal electrical connection.

[0241] In some embodiments, the housing 10 is cylindrical and has a diameter of φ, 15 mm ≤ φ ≤ 70 mm.

[0242] Among them, in order to achieve better results, φ can be selected between 30mm and 55mm. When φ is less than 15mm and φ is greater than 70mm, the battery 200 has insufficient power. When the diameter of the shell 10 is too small, the energy density of the battery cell 100 is small, and when the battery cells 100 are grouped, for example, for cylindrical battery cells 100, more space will be wasted, resulting in insufficient power for the battery 200. When the diameter of the shell 10 is too large, although the energy density of the battery cell 100 is improved, it is possible that when the remaining space in the battery 200 is large, it is still not enough to accommodate an extra row of battery cells 100. Since the number of battery cells 100 in each row is large, the battery 200 will lose more power.

[0243] The following Table 2 illustrates the effect of the design of h and φ on the total power of the battery 200. In the following table, the units of h and φ are both mm, and the unit of total power is kWh.

[0244] Table 2 The impact of h and φ design on the total power of battery 200

[0245]

[0246] This embodiment can ensure that the battery 200 has sufficient power to meet the power requirements, and can select battery cells 100 of appropriate diameter according to the internal space of the box assembly 201, so as to maximize the space utilization rate within the box assembly 201, reduce internal wasted space, and maximize the total power while keeping the volume of the battery 200 constant, thereby improving the energy density of the battery 200.

[0247] In some embodiments, as Figure 9 As shown, the electrode lead portion 3 is provided on the first end wall 13 of the housing 10, and the pressure relief component 21 is provided on the second end wall 14 of the housing 10. The thickness l1 of the first end wall 13 and the thickness l2 of the second end wall 14 satisfy the following relationship: l1≥l2.

[0248] The housing 10 may include a housing portion 1 and an end cap 2. The end cap 2 seals the opening 11 of the housing portion 1. A pressure relief component 21 is disposed on the end cap 2. The end cap 2 serves as a second end wall 14. The thickness l2 of the second end wall 14 is the thickness of the end cap 2, not the thickness at the location where the notch 22 is provided. The first end wall 13 of the housing 10 is the end wall of the housing portion 1 away from the opening l1, i.e., the end wall of the housing portion 1 where the electrode lead portion 3 is provided. The thickness l1 of the first end wall 13 and the thickness l2 of the second end wall 14 are both the thicknesses of the majority of the end wall. Since protrusions or grooves may be locally disposed on the first or second end wall 13, 14, these have little effect on the strength of the main end wall. Therefore, for ease of measurement, the thickness of the end wall is expressed as the thickness of the main end wall region.

[0249] To achieve optimal results, l1 ≥ 1.5 * l2. When l1 < l2, when thermal runaway occurs inside the battery cell 100, the deformation of the housing 10 on the pressure relief component 21 side is smaller than the deformation on the side where the electrode lead portion 3 and the first end wall 13 are located, and thermal runaway may cause damage and heat leakage.

[0250] This embodiment makes the thickness l1 of the first end wall 13 greater than the thickness l2 of the second end wall 14. When thermal runaway occurs inside the battery cell 100, the deformation of the shell 10 on the side of the pressure relief component 21 is greater than the deformation on the side where the electrode lead-out portion 3 and the first end wall 13 are located. The gas generated by the thermal runaway is reliably discharged from the pressure relief component 21 on the second end wall 14, preventing the gas from flowing toward the side where the electrode lead-out portion 3 is located, causing a large deformation of the first end wall 13, and preventing the shell 10 from being damaged and leaking heat during thermal runaway.

[0251] In some embodiments, the thickness l1 of the first end wall 13 has a size range of 0.5 mm ≤ l1 ≤ 1 mm; and / or the thickness l2 of the second end wall 14 has a size range of 0.3 mm ≤ l2 ≤ 1 mm.

[0252] Among them, in order to achieve better results, 0.6mm≤l1≤0.8mm, 0.5mm≤l2≤0.8mm.

[0253] This embodiment designs appropriate thicknesses for the first end wall 13 and the second end wall 14 so that when thermal runaway occurs in the battery cell 100 , the shell 10 is deformed to a greater extent under the action of the internal high-pressure gas, thereby preventing the shell 10 from being damaged and leaking heat during thermal runaway.

[0254] In some embodiments, as Figure 9 and Figure 10 As shown, a notch 22 is provided on the second end wall 14 , and the area of the second end wall 14 surrounded by the notch 22 forms a pressure relief component 21 .

[0255] The notches 22 may be in the shape of a circle, an ellipse, or a polygon, and the extension track of the notches 22 may be closed or open.

[0256] This embodiment can ensure that when the battery cell 100 experiences thermal runaway, after the internal pressure exceeds the preset opening pressure of the pressure relief component 21, the notch 22 ruptures to open the pressure relief component 21, and the air flow inside the shell 10 is discharged outward through the opening, thereby improving the safety of the battery cell 100.

[0257] In some embodiments, the thickness l1 of the first end wall 13 and the thickness l3 of the second end wall 14 where the notch 22 is provided satisfy the following relationship: l1 ≥ 2*l3.

[0258] Among them, in order to achieve better results, l1≥6*l3.

[0259] The thickness l3 of the second end wall 14 at the location where the notch 22 is provided is the distance between the deepest position of the notch 22 and the surface of the second end wall 14 away from the notch 22 .

[0260] This embodiment sets a dimensional relationship between the thickness l1 of the first end wall 13 and the thickness l3 of the second end wall 14 at the notch 22, so that a weak portion with lower strength than the first end wall 13 can be formed at the notch 22. When thermal runaway occurs in the battery cell 100, the internal gas can be deformed preferentially at the weak portion, causing the pressure relief component 21 to open quickly, thereby allowing the internal gas to be discharged smoothly. Moreover, even if thermal runaway occurs on the side close to the electrode lead-out portion, the gas can be preferentially flowed toward the pressure relief component 21, thereby preventing the area where the first end wall 13 is located from being deformed significantly under the action of the internal high-pressure gas, preventing the shell 10 from being damaged and leaking heat during thermal runaway, and improving the safety of the battery cell 100 on the side where the electrode lead-out portion 3 and the first end wall 13 are located.

[0261] In some embodiments, in order to achieve better results, the thickness l1 of the first end wall 13 and the thickness l3 of the second end wall 14 where the notch 22 is provided satisfy the following relationship: l1 ≥ 6*l3.

[0262] Table 3 Effect of the relationship between thickness l1 and thickness l3 on the safety of the battery cell 100

[0263]

[0264] In Table 3, for Examples 3 and 4, l1<6*l3. When the needle penetration failure test is conducted near the electrode lead-out portion 3 and the first end wall 13, a short circuit occurs in the battery cell 100, and internal thermal runaway occurs. Due to the thin thickness of the first end wall 13, the high-temperature and high-pressure gas is more likely to flow toward the first end wall 13, causing deformation or damage to the first end wall 13. The instantaneous high pressure will cause the gas to be discharged toward the side of the electrode lead-out portion 3, causing damage to the electrode lead-out portion 3, thereby leading to electrical connection failure of the battery cell 100.

[0265] In some embodiments, the electrode lead-out portion 3 is arranged on the first end wall 13 of the shell 10, and a first through hole 12 for mounting the electrode lead-out portion 3 is provided on the first end wall 13. The pressure relief component 21 is circular and has a pressure relief area. The diameter φ2 of the first through hole 12 and the diameter φ1 of the pressure relief area satisfy the following relationship: φ2≤φ1.

[0266] When φ2>φ1, when thermal runaway occurs inside the battery cell 100, the deformation of the pressure relief component 21 is smaller than that of the first end wall 13, and the area where the electrode lead 3 is mounted is more susceptible to damage and heat leakage. To achieve optimal results, φ2≤0.8*φ1.

[0267] In this embodiment, the diameter φ2 of the first through hole 12 for installing the electrode lead-out portion 3 does not exceed the diameter φ1 of the pressure relief zone, which can improve the strength of the first end wall 13 of the shell 10 where the electrode lead-out portion 3 is set. When the battery cell 100 has thermal runaway, the gas can be made to flow preferentially toward the pressure relief component 21, which can prevent the area where the first end wall 13 is located from undergoing a large deformation under the action of the internal high-pressure gas, prevent the shell 10 from being damaged and leaking heat during thermal runaway, and improve the safety of the battery cell 100 on the side where the electrode lead-out portion 3 and the first end wall 13 are located.

[0268] In some embodiments, the diameter φ2 of the first through hole 12 is in the range of 8 mm ≤ φ2 ≤ 25 mm; and / or the diameter φ1 of the pressure relief area is in the range of 20 mm ≤ φ1 ≤ 35 mm.

[0269] In order to achieve better results, 10mm≤φ2≤20mm, 22mm≤φ1≤32mm.

[0270] Among them, the first through hole 12 is used to install the electrode lead-out part 3. If the size of the first through hole 12 is too small, it will limit the diameter of the electrode lead-out part 3 and affect the flow 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 of the accommodating part 1 away from the end cover 2. When the battery cell suffers from thermal runaway, the connection between the first through hole 12 and the electrode lead-out part 3 is prone to deformation. After the gas escapes from this weak part, it will affect the safety of the side where the electrode lead-out part 3 and the first end wall 13 are located.

[0271] This embodiment ensures the strength of the shell 10 at one end where the electrode lead-out portion 3 is set by designing appropriate dimensions for the first through hole 12 and the diameter φ1 of the pressure relief zone. When thermal runaway occurs in the battery cell 100, the gas can flow preferentially toward the pressure relief component 21, thereby preventing the area where the first end wall 13 is located from undergoing a large deformation under the action of the internal high-pressure gas, preventing the shell 10 from being damaged and leaking heat during thermal runaway, and improving the safety of the battery cell 100 on the side where the electrode lead-out portion 3 and the first end wall 13 are located.

[0272] In some embodiments, the electrode assembly 4 is formed by winding a first electrode piece 45, a second electrode piece 46 and an isolating member 47 with opposite polarities around a winding axis K, the winding axis K is consistent with the first direction z, the first electrode piece 45 and the second electrode piece 46 respectively have a first electrode ear 42 and a second electrode ear 43; the center of the electrode assembly 4 is provided with a second through hole 44 extending along the first direction z, the pressure relief component 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 following relationship: φ3≥0.12*φ1.

[0273] In order to achieve better effects, φ3≥0.15*φ1, so that when thermal runaway occurs in the battery cell 100 , gas can quickly reach the pressure relief component 21 along the second through hole 44 .

[0274] Table 4 Effect of the relationship between the diameter of the second through hole 44 and the pressure relief area on the safety of the battery cell 100

[0275]

[0276] Among them, in Example 1 of Table 4, φ3<0.12*φ1. When the needle penetration failure test is performed near the electrode lead-out portion 3 and the side where the first end wall 13 is located, the battery cell 100 short-circuits and internal thermal runaway occurs. Since the diameter of the second through hole 44 is too small, the high-temperature and high-pressure gas cannot reach the pressure relief component 21 along the second through hole 44 in time, and the discharge speed is slow. The instantaneous high pressure will cause the gas to be discharged toward one side of the electrode lead-out portion, causing damage to the electrode lead-out portion, thereby leading to electrical connection failure of the battery cell 100.

[0277] In this embodiment, the diameter φ3 of the second through hole 44 and the diameter φ1 of the pressure relief zone satisfy the above relationship. When thermal runaway occurs in the battery cell 100, the second through hole 44 has a sufficient channel size to allow the internal high-pressure gas to flow quickly to the pressure relief component 21, so that the pressure relief component 21 can be opened smoothly, preventing heat from accumulating inside the battery cell 100 and being unable to be released, and preventing the shell 10 from being significantly deformed, damaged, and leaking heat, thereby improving the safety of the battery cell 100.

[0278] In some embodiments, the height of the battery cell 100 along the first direction z is h, and 60 mm ≤ h ≤ 135 mm.

[0279] To achieve optimal results, h can be selected between 70mm and 125mm. When h is less than 60mm, the battery cell 100 is insufficiently tall, resulting in a low charge in the entire power battery system. When h is greater than 135mm, it is difficult to locate the pressure relief component 21 at the bottom of the battery 200 to release the discharge. A single battery cell 100 may explode after thermal runaway, causing the entire battery 200 to catch fire and explode.

[0280] This embodiment ensures that the entire battery system has sufficient power and fully utilizes the internal space of the battery 200 by setting a suitable height for the battery cell 100. It also provides a pressure relief component 21 in the bottom area of the battery 200 to release space for discharge. In the event of thermal runaway, it can ensure that the discharge of the battery cell 100 is smoothly discharged, preventing the battery 200 from catching fire and exploding due to instantaneous high temperature and high pressure.

[0281] In some embodiments, the housing 10 is cylindrical, and the diameter of the housing 10 is φ, the height is h,

[0282] In order to achieve better results, when It is not suitable to adopt a structure in which the electrode lead-out portion 3 and the pressure relief component 21 are arranged at opposite ends of the shell 10. This is because the battery cell 100 is slender in shape. When thermal runaway occurs at a point near the electrode lead-out portion 3 inside the battery cell 100, the internal gas cannot flow to the end where the pressure relief component 21 is located in time, and heat accumulation increases. Gas is more likely to be ejected from the area where the electrode lead-out portion 3 is located, which will cause safety incidents such as fire in the entire power battery system.

[0283] The following table 5 illustrates Regarding the impact on the safety of the battery cell 100, the unit of the dimensional parameters in the following table is mm.

[0284] Table 5 Impact on the safety of the battery cell 100

[0285] h φ h / φ When the needle fails near the electrical connection side, is the electrical connection side damaged? Example 1 80 45 1.78 no Example 2 100 45 2.22 no Example 3 120 45 2.67 no Example 4 140 45 3.11 no Example 5 160 45 3.56 yes Example 6 180 45 4.00 yes Example 7 80 30 2.67 no Example 8 100 30 3.33 no Example 9 120 30 4.00 yes

[0286] In Table 5, for Examples 5, 6 and 9, The battery cell 100 has a large height-to-diameter ratio and is slender. When a needle puncture failure test is performed near the electrode lead-out portion 3 and the first end wall 13, 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 component 21 or be discharged from the pressure relief component 21 in a timely manner. The gas will be discharged toward one side of the electrode lead-out portion, causing damage to the electrode lead-out portion, thereby causing the electrical connection of the battery cell 100 to fail. For other embodiments, The ratio of the height to the diameter of the battery cell 100 is moderate. When a needle penetration failure test is carried out near the electrode lead-out portion 3 and the side where the first end wall 13 is located, if a short circuit occurs in the battery cell 100 and thermal runaway occurs inside, the high-temperature and high-pressure gas can reach the pressure relief component 21 or be discharged from the pressure relief component 21 in a timely manner, thereby preventing the gas from being discharged toward one side of the electrode lead-out portion to avoid damage to the electrode lead-out portion, thereby ensuring normal electrical connection of the battery cell 100.

[0287] This embodiment sets a suitable height-to-diameter ratio for the battery cell 100, so that when thermal runaway occurs in any area inside the battery cell 100, the internal high-pressure gas can quickly reach the pressure relief component 21 and be discharged smoothly, thereby preventing the accumulation of high-pressure gas and heat inside the battery cell 100, avoiding fire and explosion incidents in the entire power battery system, and improving the safety of battery operation.

[0288] In some embodiments, as Figure 11As shown, the shell 10 includes a first end wall 13, the first end wall 13 is provided with a first through hole 12, the electrode lead-out portion 3 of the battery cell 10 is installed in the first through hole 12 and is insulated from the first end wall 13, the electrode lead-out portion 3 is the first output pole, and the first end wall 13 is the second output pole; the battery 200 also includes a bus 202, and the battery cell 100 is provided with multiple busbars, one end of the busbar 202 is electrically connected to the electrode lead-out portion 3 of one of the battery cells 100, and the other end of the busbar 202 is electrically connected to the first end wall 13 of another battery cell 100.

[0289] The current busbar 202 can be a thin plate structure made of a metallic conductive material. For example, the current busbar 202 can include a first portion 202A, a second portion 202B, and a third portion 202C. The second portion 202B is connected between the first portion 202A and the third portion 202C. The first portion 202A is connected to the electrode lead portion 3 of one battery cell 100, and the third portion 202C is connected to the first end wall 13 of the other battery cell 100. The two battery cells 100 can be arranged adjacent to each other or spaced apart. For example, the shape of the first portion 202A can match the shape of the electrode lead portion 3, such as a circular or rectangular shape. The third portion 202C can be rectangular. A notch can be provided on the side of the third portion 202C away from the second portion 202B to provide clearance for the electrode lead portion 3 of the other battery cell 100.

[0290] This embodiment uses the electrode lead-out 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. When realizing the series connection, parallel connection or mixed connection of multiple battery cells 100 inside the battery 200, the two ends of the busbar 202 can be directly connected to the electrode lead-out portion 3 and the first end wall 13 respectively. Since only one electrode lead-out portion 3 is provided on the first end wall 13 of the shell 10, it is beneficial to increase the conductive area of the electrode lead-out portion 3, and it is also easier to achieve electrical connection on the first end wall 13 by welding or connecting with fasteners. Therefore, it can reduce the difficulty of electrical connection of multiple battery cells 100, improve the reliability of electrical connection, and ensure the working performance and reliability of the battery 200.

[0291] In some embodiments, as Figure 11 As shown, the shell 10 includes a first end wall 13, and the first end wall 13 is provided with a first through hole 12. The electrode lead-out portion 3 of the battery cell 10 is installed in the first through hole 12 and is insulated from the first end wall 13. The electrode lead-out portion 3 is the first output pole, and the first end wall 13 is the second output pole; the battery 200 also includes multiple busbars 202. In the same battery cell 100, the electrode lead-out portion 3 is electrically connected to one of the busbars 202, and the first end wall 13 is electrically connected to the other busbar 202.

[0292] In this embodiment, each battery cell 100 can be electrically connected to the other two battery cells 100 through two independent busbars 202. Since the area around the first end wall 13 located at the electrode lead-out portion 3 can be used to connect the busbars 202, it can adapt to different arrangements of multiple battery cells 100.

[0293] In some embodiments, as Figure 12 As shown, the battery 200 further includes a box assembly 201 and a support plate 203. The battery cell 100 is installed in the box assembly 201 through the support plate 203. The support plate 203 is provided with a third through hole 203' for allowing the discharge escaping through the pressure relief component 21 to flow. The pressure relief component 21 is circular and has a pressure relief area. The minimum distance D between the pressure relief component 21 and the inner wall of the box assembly 201 and the diameter φ1 of the pressure relief area satisfy the following relationship: 0.4*φ1≤D≤1.2*φ1.

[0294] For example, a support plate 203 is disposed on the inner bottom surface of the housing assembly 201. The support plate 203 is provided with a plurality of third through holes 203'. Multiple battery cells 100 are mounted on the support plate 203 with their pressure relief components 21 facing downward. The pressure relief components 21 and the third through holes 203' overlap. For example, the pressure relief components 21, the third through holes 203', and the end cap 2 are concentrically arranged. The third through holes 203' allow wastewater escaping from the battery cells 100 to flow to the discharge channel within the battery 200, and ultimately be discharged to the outside through the pressure relief components on the housing assembly 201 of the battery 200.

[0295] The distance D is designed based on the diameter φ1 of the pressure relief zone. For optimal performance, 0.67*φ1≤D≤φ1. When D < 0.4*φ1, the distance D between the pressure relief component 21 and the inner wall of the housing assembly 201 is too small, preventing the active material from being effectively ejected and preventing rapid cooling of the battery 200. When D > 1.2*φ1, the distance D between the pressure relief component 21 and the inner wall of the housing assembly 201 is too large, occupying the height of the battery cell 100 and affecting energy density.

[0296] For example, the size range of φ1 is 20 mm to 35 mm, preferably 22 mm to 32 mm. The size range of D is 10 mm to 30 mm, preferably 15 mm to 25 mm.

[0297] Table 6 below illustrates the effect of the distance D design on the battery's temperature dropping to a preset level after thermal runaway. The units of all dimensional parameters in the following table are in mm.

[0298] Table 6 Effect of the design of the distance D in the battery on the temperature after thermal runaway

[0299]

[0300] In Example 1, D < 0.67*φ1, and the distance D is too small. When thermal runaway occurs in the battery cell 100, the exhaust cannot be discharged through the third through-hole 203' in a timely manner. The internal temperature of the battery 200 rises sharply, and the time required to cool to 120°C is twice that of other embodiments. In Example 4, D > 1.2*φ1, and the distance D is too large. Although the exhaust cannot be discharged through the third through-hole 203' in a timely manner when thermal runaway occurs in the battery cell 100, the thickness of the support plate 203 is relatively large, significantly reducing the height of the battery cell 100 and affecting the energy density of the battery cell 100.

[0301] This embodiment sets a suitable distance D between the pressure relief component 21 and the inner wall of the box assembly 201. This can effectively eject the internal gas and active material when thermal runaway occurs in the battery cell 100, thereby quickly cooling the battery 200. It can also maximize the height of the battery cell 100 while ensuring thermal runaway safety, thereby increasing the energy density of the battery cell 100 and enabling the battery 200 to provide greater power.

[0302] In some embodiments, the electrical device includes a vehicle 300 , the battery 200 is disposed between a cabin 301 and a vehicle floor 302 , the electrode lead-out portion is disposed toward the cabin 301 , and the pressure relief component 21 is disposed toward the vehicle floor 302 .

[0303] This embodiment enables the battery 200 to release waste toward the bottom of the vehicle if thermal runaway occurs during use. Since the pressure relief component 21 of the battery cell 100 is disposed toward the vehicle floor 302, that is, downward, if the pressure relief component 21 is opened, waste released by the battery 200 will be ejected toward the bottom of the vehicle, thereby reducing the impact of high temperature and high pressure on the cabin 301 and passengers, and improving the safety of the vehicle 300 during use.

[0304] In some specific embodiments, Figures 3 to 5 As shown, the battery cell 100 is cylindrical and includes a housing 10, an electrode assembly 4, and an electrode lead 3. The housing 10 includes a housing 1 and an end cap 2. The housing 1 is a cylindrical structure with an opening 11 at one end along a first direction z (central axis). The end cap 2 closes the opening 11. The housing 1 includes a first end wall 13 and a side wall 15. The end cap 2 serves as a second end wall 14.

[0305] The end cap 2 is integrally provided with a pressure relief component 21, which may be circular and located at the center of the end cap 2. The first end wall 13 is provided with a first through hole 12, which is located at the center of the first end wall 13, and the electrode lead portion 3 is mounted in the first through hole 12.

[0306] The electrode assembly 4 includes an electrode body 41, a first electrode tab 42, and a second electrode tab 43. The first and second electrode tabs 42, 43 are located at opposite ends of the electrode body 41 along a first direction z, which coincides with the winding axis. The first electrode tab 42 is electrically connected to the electrode lead 3 via a first current collector 5, and the second electrode tab 42 is electrically connected to the end cap 2 via a second current collector 6. The end cap 2 is welded to the housing 1, allowing the second electrode tab 43 to transfer electrical energy to the first end wall 13 via the second current collector 6, the end cap 2, and the side wall 15. For example, the electrode lead 3 serves as the positive output terminal, and the first end wall 13 serves as the negative output terminal, or vice versa.

[0307] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: An electrode assembly (4) comprises an electrode body (41) and a first electrode tab (42) and a second electrode tab (43) with opposite polarities, wherein the first electrode tab (42) and the second electrode tab (43) are led out from the electrode body (41); A first output pole and a second output pole, wherein the first output pole is electrically connected to the first pole lug (42), and the second output pole is electrically connected to the second pole lug (43); A housing (10) for accommodating the electrode assembly (4), the housing (10) being provided with a pressure relief component (21), wherein along a first direction (z), the first output pole and the second output pole are arranged at one end of the housing (10), and the pressure relief component (21) is arranged at the other end of the housing (10); The electrode assembly (4) is cylindrical, the shell (10) comprises 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) and arranged opposite to each other along the first direction (z), the second end wall (14) is provided with the pressure relief component (21), the shell (10) is cylindrical, the pressure relief component (21) is arranged at the center of the second end wall (14) and is circular, the pressure relief component (21) has a pressure relief area, and the diameter φ1 of the pressure relief area and the diameter φ of the shell (10) satisfy the following relationship: 0.35≤ ≤0.

85.

2. The battery cell according to claim 1, wherein: The first end wall (13) is provided with a first through hole (12), and the electrode lead portion (3) of the battery cell (100) is installed in the first through hole (12) and is insulated from the first end wall (13); The electrode lead-out portion (3) is the first output pole, and the first end wall (13) is the second output pole.

3. The battery cell according to claim 1, wherein: The housing (10) comprises: a housing portion (1) and an end cover (2); the housing portion (1) has an opening (11); the end cover (2) is used to cover the opening (11); the housing portion (1) is formed by the first end wall (13) and the side wall (15); and the end cover (2) is the second end wall (14).

4. The battery cell according to claim 1, wherein: The housing (10) comprises: a housing portion (1) and an end cover (2); the housing portion (1) has an opening (11); the end cover (2) is used to cover the opening (11); the housing portion (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 claim 2, characterized in that The first pole tab (42) is led out from the electrode body (41) along the first direction (z) facing the electrode lead portion (3), and the second pole tab (43) is led out from the electrode body (41) along the first direction (z) away from the electrode lead portion (3). The first pole tab (42) is electrically connected to the electrode lead portion (3), and the second pole tab (43) is electrically connected to the first end wall (13).

6. The battery cell according to claim 5, characterized in that The first electrode tab (42) is electrically connected to the electrode lead-out portion (3) via the first current collecting member (5), and the second electrode tab (43) is electrically connected to the first end wall (13) via the second current collecting member (6).

7. The battery cell according to claim 6, characterized in that The second current collecting member (6) contacts the side wall (15) to achieve electronic conduction between the second electrode tab (43) and the first end wall (13).

8. The battery cell according to claim 6, characterized in that The housing (10) comprises: a housing portion (1) and an end cover (2); the housing 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 achieve electronic conduction between the second electrode tab (43) and the first end wall (13).

9. The battery cell according to claim 6, characterized in that: The housing (10) comprises: a housing portion (1) and an end cover (2); the housing 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 achieve electronic conduction between the second electrode tab (43) and the first end wall (13).

10. The battery cell according to claim 6, characterized in that Along the first direction (z), the second current collecting member (6) is located between the pressure relief member (21) and the second electrode tab (43), and a hollow portion (6') is provided on the second current collecting member (6), wherein the hollow portion (6') is used to conduct gas between a space on one side of the second current collecting member (6) facing the second electrode tab (43) and a space on the other side facing the pressure relief member (21).

11. The battery cell according to claim 10, characterized in that The hollow portion (6') comprises at least one fourth through hole (61), wherein one of the fourth through holes (61) is provided at a central position of the second current collecting member (6).

12. The battery cell according to claim 11, characterized in that A plurality of the fourth through holes (61) are provided, and the remaining fourth through holes (61) are distributed around the fourth through hole (61) located at the center.

13. The battery cell according to claim 11, characterized in that The hollow portion (6') further comprises a plurality of cutouts (63), wherein the cutouts (63) penetrate the second current collecting member (6) along the first direction (z), and the plurality of cutouts (63) surround the fourth through hole (61).

14. The battery cell according to claim 13, characterized in that One end of the cutout (63) is in communication with the fourth through hole (61) and extends in a direction away from the fourth through hole (61).

15. The battery cell according to claim 11, characterized in that The hollow portion (6') further comprises a score line (62), and the score line (62) passes through the second current collecting member (6) along the first direction (z).

16. The battery cell according to claim 15, characterized in that A plurality of the engraved lines (62) are provided, and one end of the engraved line (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 claim 2, characterized in that The first pole tab (42) and the second pole tab (43) are both led out from one end of the electrode body (41) facing the electrode lead portion (3) along the first direction (z), the first pole tab (42) is electrically connected to the electrode lead portion (3), and the second pole tab (43) is electrically connected to the first end wall (13).

18. The battery cell according to claim 2, characterized in that It also includes a first current collecting member (5) and a second current collecting member (6), wherein the first electrode tab (42) is electrically connected to the electrode lead portion (3) through the first current collecting member (5), and the second electrode tab (43) is electrically connected to the first end wall (13) through the second current collecting member (6); The electrode lead-out portion (3) comprises a base (31) and a main body (32); the base (31) is located between the first end wall (13) and the first current collecting member (5), and is used to limit the movement of the electrode lead-out portion (3) along the first direction (z) in a direction away from the interior of the housing (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 (32) is located in the first through hole (12).

19. The battery cell according to claim 18, characterized in that Along the first direction (z), the maximum thickness t1 of the base (31) satisfies: 0.6 mm ≤ t1 ≤ 1.2 mm; and / or the maximum thickness t2 of the first current collecting member (5) satisfies: 0.3 mm ≤ t2 ≤ 0.7 mm; and / or the maximum thickness t3 of the second current collecting member (6) satisfies: 0.3 mm ≤ t3 ≤ 0.7 mm.

20. The battery cell according to claim 19, characterized in that 0.8mm≤t1≤1mm, and / or 0.4mm≤t2≤0.6mm, and / or 0.4mm≤t3≤0.6mm.

21. The battery cell according to claim 18, characterized in that The electrode lead-out portion (3) further includes a limiting protrusion (33), the base (31) and the limiting protrusion (33) are both connected to and protrude from the outer peripheral wall of the main body (32), the limiting protrusion (33) and the base (31) are respectively located on the outer side and the inner side 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. The battery cell according to claim 21, characterized in that The main body (32) is provided with a recess (34), the bottom wall of the recess (34) is connected to the first current collecting member (5) to achieve electronic conduction between the electrode lead portion (3) and the first electrode tab (42), and the opening of the recess (34) is provided on a side of the main body (32) facing and / or away from the interior of the shell (10).

23. The battery cell according to claim 22, characterized in that The bottom wall of the recess (34) is laser welded to the first current collecting member (5) on a side of the main body (32) facing away from the interior of the housing (10).

24. The battery cell (100) according to claim 1, characterized in that 15mm≤φ≤70mm.

25. The battery cell according to any one of claims 1 to 24, characterized in that: The thickness of the first end wall (13) l 1 and the thickness of the second end wall (14) l 2 satisfies the following relationship: l 1≥ l 2.

26. The battery cell according to claim 25, characterized in that l 1≥1.5* l 2。 27. The battery cell according to claim 25, characterized in that The thickness of the first end wall (13) l 1. The size range is: 0.5mm≤ l 1≤1mm; and / or the thickness of the second end wall (14) l 2. The size range is: 0.3mm≤ l 2≤1mm.

28. The battery cell according to claim 27, characterized in that 0.6mm≤ l 1≤0.8mm, and / or 0.5mm≤ l 2≤0.8mm.

29. The battery cell according to any one of claims 1 to 24, characterized in that: The second end wall (14) is provided with a notch (22), and the area of the second end wall (14) surrounded by the notch (22) forms the pressure relief component (21).

30. The battery cell according to claim 29, characterized in that The thickness of the first end wall (13) l 1 and the thickness of the second end wall (14) at the location where the notch (22) is provided l 3 satisfies the following relationship: l 1≥2* l 3.

31. The battery cell according to claim 30, characterized in that l 1≥6* l 3。 32. The battery cell according to claim 2, characterized in that The diameter φ2 of the first through hole (12) and the diameter φ1 of the pressure relief zone satisfy the following relationship: φ2≤φ1.

33. The battery cell according to claim 32, characterized in that The size range of the diameter φ2 of the first through hole (12) is: 8mm≤φ2≤25mm; and / or the size range of the diameter φ1 of the pressure relief zone is: 20mm≤φ1≤35mm.

34. The battery cell according to any one of claims 1 to 24, wherein: The electrode assembly (4) is formed by winding a first pole piece (45), a second pole piece (46), and a separator (47) with opposite polarities around a winding axis (K), wherein the winding axis (K) is consistent with the first direction (z), and the first pole piece (45) and the second pole piece (46) respectively have the first pole tab (42) and the second pole tab (43); A second through hole (44) extending along the first direction (z) is provided at the center of the electrode assembly (4), and the maximum diameter φ3 of the second through hole (44) and the diameter φ1 of the pressure relief zone satisfy the following relationship: φ3≥0.12*φ1.

35. A battery, characterized in that: include: The battery cell (100) according to any one of claims 1 to 34.

36. The battery according to claim 35, characterized in that The housing (10) includes a first end wall (13), the first end wall (13) is provided with a first through hole (12), the electrode lead portion (3) of the battery cell (100) is mounted in the first through hole (12) and is 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 includes a busbar (202), wherein the battery cells (100) are provided in plurality, one end of the busbar (202) is electrically connected to the electrode lead-out portion (3) of one of the battery cells (100), and the other end of the busbar (202) is electrically connected to the first end wall (13) of another of the battery cells (100).

37. The battery according to claim 35 or 36, characterized in that The housing (10) includes a first end wall (13), the first end wall (13) is provided with a first through hole (12), the electrode lead portion (3) of the battery cell (100) is mounted in the first through hole (12) and is 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 current collectors (202); in the same battery cell (100), the electrode lead-out portion (3) is electrically connected to one of the current collectors (202), and the first end wall (13) is electrically connected to another current collector (202).

38. The battery according to claim 35, characterized in that The battery (200) further comprises a support plate (203) and a box assembly (201), wherein the battery cell (100) is mounted in the box assembly (201) via the support plate (203), and a third through hole (203') is provided on the support plate (203) for allowing discharge from the pressure relief component (21) to flow, wherein the pressure relief component (21) is circular and has a pressure relief area, and the minimum distance D between the pressure relief component (21) and the inner wall of the box assembly (201) and the diameter φ1 of the pressure relief area satisfy the following relationship: 0.4*φ1≤D≤1.2*φ1.

39. An electrical device, characterized in that: The battery (200) comprises the battery (200) according to any one of claims 35 to 38, wherein the battery (200) is used to provide electrical energy to the electrical device.

40. The electrical device according to claim 39, characterized in that: The power-consuming device includes a vehicle (300), the battery (200) is arranged between a cabin (301) and a vehicle floor (302), the first output pole and the second output pole are both arranged toward the cabin (301), and the pressure relief component (21) is arranged toward the vehicle floor (302).

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