Battery cell, battery and electrical device

Abstract

A battery cell, comprising: an electrode assembly comprising a first connecting tab; a housing designed to accommodate the electrode assembly; an electrode connection attached to the housing, wherein the electrode connection comprises a first concave section and a connecting section at the bottom of this first concave section; and a current collector element that is connected to the first connecting lug and welded to the connecting section.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] This application claims priority over International Patent Application No. PCT / CN2021 / 114156, filed on August 23, 2021 and entitled “BATTERY CELL, MANUFACTURING METHOD FOR IT AND MANUFACTURING SYSTEM FOR IT, BATTERY AND ELECTRICAL DEVICE”, which is incorporated herein by reference in its entirety. TECHNICAL AREA

[0002] The present application relates to the field of battery technologies, in particular to a battery cell, a battery and an electrical device. BACKGROUND

[0003] Battery cells are commonly used in electronic devices such as mobile phones, laptops, battery-powered cars, electric vehicles, electric airplanes, electric boats, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-hydrogen battery cells, lithium-ion battery cells, secondary alkaline zinc-manganese battery cells, and similar types.

[0004] When developing battery technologies, the question arises as to how the safety of battery cells can be improved, which represents a research direction in battery technology. SUMMARY

[0005] This application describes a battery cell, a battery and an electrical device that serve to improve the safety of battery cells.

[0006] According to a first aspect, in one embodiment of this application, a battery cell is provided. The battery cell comprises an electrode assembly, a housing, an electrode terminal, and a current collector. The electrode assembly includes a first terminal. The housing serves to accommodate the electrode assembly. The electrode terminal is located in the housing and comprises a first concave section and a connecting section at the bottom of this first concave section. The current collector is connected to the first terminal and welded to the connecting section.

[0007] As part of the aforementioned technical solution, a first concave-shaped area is implemented at the electrode connection to reduce the material thickness of the connecting element. This results in a reduction of the energy required to weld the connecting element to the current element, minimizes the heat generated, reduces the likelihood of damage to other components due to overheating, and improves overall operational reliability.

[0008] In some designs, the current collector is welded to the connecting section, creating a first weld area. In the direction of thickening of the connecting section, this first weld area extends from the side of the connecting section facing away from the current collector at least as far as the interior of the current collector.

[0009] In the previously described technical solution, the first welding section extends from the connection section into the current collector to establish a connection between these two components. This reduces the contact resistance between the current collector and the electrode terminal and increases the current capacity.

[0010] In some designs, the first weld area in the thickening direction of the connection section does not protrude beyond the current collector surface facing away from the connection section.

[0011] In the previously described technical solution, the first welding section is positioned at a predetermined distance from the surface of the current collector facing away from the joint section. This serves to prevent the current collector from melting through, to reduce the risk of metal particle formation on its opposite surface, and to increase safety.

[0012] In some embodiments, the housing comprises a cylinder and a cover connected to the cylinder. The cylinder is arranged around the circumference of the electrode assembly. The cover is provided with an opening for the electrode feedthrough. The electrode connector is secured in the electrode feedthrough. The first weld section and the cover are both annular, the outer diameter of the cover is D0, the inner diameter of the first weld section is D1, and D1 and D0 are equal to 0.1 <D1 / / D0<0,6.

[0013] D0 correlates positively with the diameter of the electrode assembly. The larger D0 is, the higher the capacity of the electrode assembly and the greater the current flow area required by the battery cell for the first welding section. The smaller D1 is, the smaller the circumference of the first welding section and the smaller the current flow area of ​​the first welding section. If D1 / D0 is too small, D1 will be relatively small because D0 is relatively large. Consequently, the current flow area of ​​the first welding section will be insufficient, leading to significant overheating during charging and discharging. This makes it difficult to meet the battery cell's requirements for current capacity and limiting the temperature rise during fast charging.

[0014] The larger D1 is, the larger the electrode feedthrough opening and the smaller the cover area. Conversely, the smaller D0 is, the smaller the cover area. If D1 / D0 is too large, D1 becomes relatively large because D0 is relatively small. This can cause the cover to deform easily due to vibrations of the battery cell, potentially creating safety hazards. The cover can be used as the output electrode of the battery cell, which is connected to a busbar. If D1 / D0 is too large, the cover contact areas with the busbar and the current flow area between the cover and the busbar are relatively small. The heat generated at the connection point between the cover and the busbar is correspondingly high, making it difficult to meet the battery cell's requirements for current carrying capacity and temperature rise control during fast charging.

[0015] In the aforementioned technical solution, 0.1≤D1 / D0≤0.6 is regulated to meet the battery cell's requirements for current capacity and temperature rise control, and to increase the battery cell's safety.

[0016] In some embodiments, the first weld section represents an open structure, and the central angle α of the first weld section is in the range of 180° to 330°.

[0017] α is positively correlated with the current flow area of ​​the first weld section. The smaller α, the smaller the current flow area of ​​the first weld section and the greater the heat generation when current flows through it. In the previously described technical solution, α is set in the range of 180° to 330° to ensure that the first weld section meets the battery cell's requirements regarding current capacity and temperature rise control. The first weld section has an open structure, with an unwelded area between its two ends circumferentially relieving welding stresses and reducing stress concentration.

[0018] In some embodiments, the first welding section forms a closed structure to increase the welding area and improve the weld strength and current capacity of the first welding section.

[0019] In some embodiments, 0.2≤D1 / D0≤0.4.

[0020] In some embodiments, D1 is in the range of 5 mm to 14 mm to meet the battery cell requirements for current capacity and temperature rise control.

[0021] In some embodiments, the cover and cylinder are manufactured as a single piece. This eliminates the need for joining the cover and cylinder. When the cover and cylinder are electrically connected to a positive or negative electrode of the electrode assembly, the resistance at the junction between the cover and cylinder is low precisely because the connection between the cover and cylinder is an integrated structure, thus improving current capacity. The cover can be designed to be connected to an external component (for example, the busbar). If the battery cell is subjected to an external impact, the external component can pull the cover along with it, subjecting the joint between the cover and the cylinder to a force.In the described technical solution, the cover and cylinder are manufactured as a single piece. This serves to improve the connection strength between the cover and the cylinder and thus reduce the risk of failure at this connection point.

[0022] In some embodiments, in the thickening direction of the connection section, the dimension h of the first weld section is the thickness of a region of the connection section for welding to the current collector d0, and d0 and h satisfy conditions 1. <h / d0≤1,5.

[0023] Provided that h / d0 ≤ 1, the penetration depth of the first weld section is shallow. Because the first weld section is formed integrally with the connecting section, a cold solder joint is created, making it difficult for the first weld section to effectively connect the current collector and the connecting section. If d0 is constant, the power required for welding increases with increasing h, and consequently, so does the heat generated during welding. If h is too large, the high temperature generated during welding can easily damage components in the electrode connection area, creating potential safety hazards.

[0024] In the present technical solution, the ratio 1 <h / d0≤1,5 geregelt. Dieses dient dazu, die beim Schweißprozess entstehende Wärme sowie die Schweißschwierigkeit zu minimieren, stets unter der Voraussetzung, dass eine zuverlässige Verbindung zwischen dem Stromsammelelement und dem Verbindungsabschnitt sichergestellt ist.

[0025] In some embodiments, the thickness of a region of the current collector element for welding to the connecting section d1, and d0 and d1 satisfy 0.5≤d1 / d0≤1.2.

[0026] The smaller d1 is at a constant d0, the more easily the current collector element melts through during welding and the more easily the high-temperature particles generated during welding fall into the battery cell; and the larger d1 is, the larger the space occupied by the current collector element, the higher the weight and the lower the energy density of the battery cell.

[0027] To minimize the risk of the current collector element melting and at the same time limit the loss of energy density of the battery cell, a ratio of 0.5≤d1 / d0≤1.2 is set in the previously described technical solution.

[0028] In some embodiments, d0 is between 0.4 mm and 1.2 mm to meet the battery cell requirements regarding current capacity and temperature rise control. This reduces welding heat and increases safety.

[0029] In some embodiments, at least part of the first terminal tab is located on a side of the current collector facing away from the electrode terminal and supports the current collector.

[0030] In the aforementioned technical solution, the first terminal lug can support the current collector, thus securing the current collector to the connection section. The first terminal lug can limit the relative movement of the current collector to the connection section during battery cell vibrations. This reduces the stress on the first weld point and minimizes the risk of it cracking. During welding of the connection section and the current collector, the first terminal lug can support the current collector. This reduces the relative displacement between the current collector and the connection section during welding and minimizes the risk of a cold solder joint.

[0031] In some embodiments, a first part of the first connecting tab is arranged on the side of the connecting section facing away from the first concave section and is intended to hold a part of the current collecting element that is opposite the connecting section.

[0032] In the previously described technical solution, the first part can support the area of ​​the current collector opposite the connection section. This ensures that the current collector and the connection section are firmly in contact, reducing the risk of cold solder joints. Furthermore, the first weld seam can reduce deformation of the current collector during welding and optimize its shape.

[0033] In some embodiments, the first section is welded to the current collector element to form a second weld area.

[0034] The present technical solution enables the second welding area to reduce the contact resistance between the current collector and the first terminal, thereby increasing the current capacity. The second welding area is located in close proximity to the connection area, thus reducing the conductive path between the connection area and the second welding area. This results in a reduction in resistance and an increase in current capacity.

[0035] In some designs, a second section of the first connecting tab encloses the circumference of the first section and is designed to support an area of ​​the current collector element that is not located opposite the connecting section.

[0036] By arranging the second section in the described technical solution, the current-collecting area of ​​the supporting region of the first tab can be increased. This leads to a stronger supporting effect of the first tab, a reduction in pressure between the first tab and the current collector element, and a reduction in the risk of the first tab being crushed.

[0037] In some embodiments, the second section is welded to the current collector element to form a third weld area.

[0038] The present technical solution enables the third welding area to reduce the contact resistance between the current collector element and the second section, thus increasing the current capacity.

[0039] In some embodiments, the current collector element has a convex section on one side facing the first flag, and the convex section is welded to the second section to form the third welded section.

[0040] With the technical solution described above, the convex section can be better adapted to the second area, which reduces the risk of poor welding results.

[0041] In certain implementations, the first flag is positioned around the central axis of the electrode assembly, with a cross-section of the first flag perpendicular to the central axis being annular. The outer radius of the first flag is R, the minimum distance between the third weld section and the central axis in the radial direction of the first flag is D2, and R and D2 satisfy 0.2≤D2 / R≤0.8.

[0042] R is positively correlated with the diameter of the electrode assembly. As R increases, the current generated by the electrode assembly also increases, which in turn places higher demands on the current-carrying area of ​​the battery cell. A portion of the current collector element near the central axis can be used for welding to the junction; and the smaller the diameter D2, the smaller the area of ​​the current collector element that can be welded to the junction, and the smaller the current-carrying area between the current collector element and the junction. If D2 / R is too small, R is relatively large because D2 is relatively small. The result is an insufficient current-carrying area between the current collector element and the junction. This generates a significant amount of heat at the weld point between the current collector element and the junction during charging and discharging.This poses a problem because the battery cell's requirements for current carrying capacity and temperature rise control during fast charging are difficult to meet.

[0043] The first flash plate contains several flash layers. The larger D2 is, the outer the flash layer directly connected to the third weld section. If D2 is too large, the number of flash layers connected to the third weld section is comparatively small. Furthermore, the distance between the third weld section and the innermost flash layer is too great. This results in the current path between the outermost flash layer and the electrode terminal differing significantly from that between the innermost flash layer and the electrode terminal. The result is an inhomogeneous current density across the first electrode plate and an increase in internal resistance.

[0044] In the aforementioned technical solution, D2 / R is controlled within a range of 0.2 to 0.8 to minimize current path differences between various areas of the first tab and the electrode terminal. This improves the homogeneity of the current density of the first electrode plate of the electrode assembly and reduces the internal resistance, thereby meeting the battery cell's requirements for current carrying capacity and temperature rise.

[0045] In some embodiments, D2 and R satisfy the conditions 0.2≤D2 / R≤0.5.

[0046] In some embodiments, D2 is in the range of 3.5 mm to 10 mm to reduce the internal resistance of the electrode assembly and thus meet the battery cell requirements for current capacity and temperature rise control.

[0047] In some embodiments, the diameter of the current collector element is D3, the diameter of the first flag is D4, and D3 is smaller than D4.

[0048] As part of the previously described technical solution, the current collector element has a reduced diameter. This helps to minimize the space required for the current collector element, reduce its weight, and consequently increase the energy density of the battery cell.

[0049] In some embodiments, D3 and D4 correspond to 0.75≤D3 / D4≤0.97.

[0050] If D4 is constant and D3 is simultaneously too low, the distance between the outer area of ​​the first terminal and the current collector increases. This significantly lengthens the conductive path between the two components, resulting in a relatively high internal resistance of the electrode assembly and thus negatively impacting the battery cell's performance. In the aforementioned technical solution, D3 / D4 is controlled to be ≥ 0.75 in order to reduce the internal resistance of the electrode assembly and improve the charging and discharging performance of the battery cell.

[0051] Provided that D4 is constant and D3 has an excessive value, assembly errors lead to fluctuations in the coaxiality between the current collector and the electrode assembly. This results in the current collector protruding beyond the outer circumferential surface of the electrode assembly, making it difficult to insert the current collector and electrode assembly into the housing. This negatively impacts assembly efficiency and increases the product's defect rate.

[0052] Under the condition that D4 is constant and D3 has an excessive value, assembly errors lead to fluctuations in the coaxiality between the current collector and the electrode assembly. This results in the current collector protruding beyond the outer circumferential surface of the electrode assembly, making it difficult to insert the current collector and electrode assembly into the housing. This negatively impacts assembly efficiency and the product defect rate. The aforementioned technical solution controls D3 / D4 ≤ 0.97 to reduce the risk of the current collector protruding from the outer circumferential surface of the electrode assembly due to errors, thereby improving assembly efficiency and product quality.

[0053] In some embodiments, D3 is located in the range of 35 mm to 44 mm. By controlling D3 in the range of 35 mm to 44 mm, the internal resistance of the electrode assembly can be reduced, the charging and discharging performance of the battery cell improved, and the risk of the current collector element protruding from the outer circumferential surface of the electrode assembly due to defects reduced.

[0054] In some designs, the connecting section has a groove that extends from a first outer surface of the connecting section towards the electrode assembly, and the first welding section extends from the bottom wall of the groove at least as far as the current collector element.

[0055] In battery cell manufacturing, an external device must interact with the connection section. The surface of the first weld section is uneven, and if the external device is pressed against it, it can easily be squeezed through. The present technical solution creates a gap between the first outer surface and the bottom of the groove. This allows the first outer surface to be designed in such a way that it supports the external device, separates it from the first weld section, and thus reduces the risk of damage to the external device from being squeezed.

[0056] In some embodiments, the housing comprises a cylinder and a cover connected to the cylinder. The cylinder is arranged around the circumference of the electrode assembly. The cover is provided with an opening for the electrode feedthrough. The electrode connector is secured in the electrode feedthrough. The electrode connector comprises a connector body. This connector body comprises a column-shaped section, a first and a second retaining element, at least a portion of the column-shaped section being located in the electrode feedthrough, the first concave section being arranged within the column-shaped section, and both the first and second retaining elements being connected to and projecting from the outer side wall of the column-shaped section. The first and second retaining elements are located on the outside and inside, respectively.They are arranged on the inside of the cover and are configured together to clamp part of the cover.

[0057] In the above technical solution, the first and second retaining elements clamp the part of the cover from two sides to secure the connector body to the cover.

[0058] In some embodiments, the terminal body has a second outer surface, and the first concave section is recessed from the second outer surface towards the electrode assembly to the first outer surface of the connection section.

[0059] In some embodiments, the electrode connection also includes a sealing plate that is connected to the connection body and seals the opening of the first concave part.

[0060] In the aforementioned technical solution, the sealing plate can protect the connection section from the outside, thereby reducing the ingress of external contaminants into the first concave section, reducing the risk of damage to the connection section by external contaminants, and improving the sealing efficiency of the battery cell.

[0061] In some embodiments, the electrode assembly also includes a second terminal with a polarity opposite to that of the first terminal, the second terminal being arranged around the central axis of the electrode assembly. The first terminal is located at an end of the electrode assembly facing the electrode terminal, the second terminal is located at an end of the electrode assembly away from the electrode terminal, and the second terminal is electrically connected to the housing.

[0062] In the aforementioned technical solution, the casing itself can be used as an output electrode of the battery cell, thus eliminating the need for a conventional electrode connection and simplifying the battery cell structure. When multiple battery cells are assembled into a group, the casing can be electrically connected to the busbar. This not only increases the current flow area but also allows for a more flexible busbar design.

[0063] In some embodiments, the second terminal is a negative electrode terminal, and the substrate material of the housing is steel. The steel housing is largely resistant to corrosion by the electrolyte in the low-potential state.

[0064] In some designs, the casing has an opening at one end opposite the electrode connection. The battery cell also contains a cover plate to seal this opening.

[0065] According to a second aspect, an embodiment of this application includes a battery that encloses the battery cell according to one of the embodiments of the first aspect.

[0066] A third aspect of this application relates to an electrical device which contains the battery according to the second aspect, wherein the battery is designed to supply electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] To describe the technical solutions in the embodiments of this application more clearly, the accompanying drawings, which are necessary for describing the embodiments of this application, will be briefly discussed below. The accompanying drawings in the following descriptions represent only some exemplary embodiments of this application, and it is possible for a person skilled in the art to derive other representations from these drawings without any creative effort. Fig. Figure 1 shows a schematic structural diagram of a vehicle according to some embodiments of this application; Fig. Figure 2 shows a schematic exploded view of a battery as used in some embodiments of the present application; Fig. Figure 3 shows a schematic structure diagram of a battery module. Fig. 2; Fig. Figure 4 shows a schematic exploded view of a battery cell as used in some embodiments of the present application; Fig. Figure 5 shows a schematic cross-sectional view of a battery cell according to certain embodiments of this application; Fig. Figure 6 shows an enlarged partial diagram of the battery cell Fig. 5; Fig. Figure 7 shows an enlarged schematic representation of Block B in Fig. 6; Fig. Figure 8 shows an enlarged schematic representation of circle C in Fig. 7; Fig. Figure 9 shows a schematic representation of the terminal body of an electrode terminal of a battery cell according to certain embodiments of this application; Fig. Figure 10 shows a schematic representation of the terminal body of an electrode terminal of a battery cell according to certain embodiments of this application; Fig. Figure 11 shows a schematic structure diagram of an electrode assembly and a current collection element of a battery cell according to some embodiments of this application; Fig. Figure 12 shows a schematic structure diagram of an electrode assembly and a current collection element of a battery cell according to some other embodiments of this application; Fig. Figure 13 shows a partially schematic cross-sectional view of a battery cell according to certain embodiments of this application; Fig. Figure 14 shows an enlarged schematic representation of Block E in Fig. 13; Fig. Figure 15 shows a schematic exploded view of an electrode terminal of a battery cell as used in some embodiments of the present application; Fig. Figure 16 shows a schematic top view of an electrode terminal of a battery cell according to some embodiments of this application; Fig. Figure 17 shows a partially schematic cross-sectional view of a battery cell according to certain embodiments of this application; Fig. Figure 18 shows a partially schematic cross-sectional view of a battery cell according to embodiments yet to be determined of this application; and Fig. Figure 19 shows a partially schematic cross-sectional view of a battery cell according to certain embodiments of this application.

[0068] The illustrations in the attached drawings are not to scale. DESCRIPTION OF THE EXECUTION FORMS

[0069] To better clarify the objectives, technical solutions, and advantages of the embodiments of this application, the technical solutions in the embodiments of this application are clearly described below with reference to the accompanying drawings. It is evident that the described embodiments represent some, but not all, embodiments of this application. All other embodiments that a person skilled in the art can derive from the embodiments of this application without inventive effort are within the scope of protection of this application.

[0070] Unless otherwise specified, all technical and scientific terms used in this application correspond to the general understanding of those skilled in the field. The terms used in this specification are intended only to describe the specific embodiments and not to limit the scope of this application. The terms "comprising," "containing," and any variations thereof in the description and claims of this application, as well as in the description of the preceding figures, signify non-exclusive inclusion. In the description, claims, or accompanying drawings of this application, the terms "first," "second," and the like serve to distinguish between different objects and not to indicate a particular order or relative importance.

[0071] When this application refers to an "embodiment," it means that certain features, structures, or properties described with reference to the embodiment may be included in at least one embodiment of this application. The word "embodiment," appearing at various points in the description, does not necessarily refer to the same embodiment or to an independent or alternative embodiment that excludes other embodiments.

[0072] It should be noted in the description of this application that the terms "assemble," "connect," "join," and "fasten" are to be understood in their general sense unless expressly stated and defined otherwise. They may, for example, refer to a permanent connection, a detachable connection, or an integral connection; to a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. A person with ordinary technical knowledge will be able to understand the specific meanings of these terms in this application that are appropriate for particular situations.

[0073] In this application, the term "and / or" is merely an associative relationship used to describe connected objects, meaning that three relationships are possible. For example, A and / or B can represent three states: the sole presence of A; the presence of both A and B; and the sole presence of B. Furthermore, the forward slash " / " in this application generally symbolizes an "OR" connection between contextually related objects.

[0074] In the embodiments of this application, the same reference numerals denote the same elements. For the sake of brevity, detailed descriptions of the same elements are not repeated in the various embodiments. It should be understood that the dimensions shown in the accompanying drawings, such as the thickness, length, and width of various elements, as well as dimensions such as the thickness, length, and width of integrated devices, are for illustrative purposes only in the embodiments of this application and are not intended to constitute any limitations of this application.

[0075] In this application, “a multitude” means more than two (including two).

[0076] In this application, the term "parallel" encompasses not only the absolutely parallel case, but also the approximately parallel case in the conventional technical understanding; likewise, the term "perpendicular" encompasses not only the absolutely perpendicular case, but also the approximately perpendicular case in the conventional technical understanding.

[0077] The battery cell in the application may comprise a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, or the like. This is not limited in the embodiments of the present application.

[0078] The battery mentioned in the embodiments of this application is a single physical module containing one or more battery cells to provide a higher voltage and capacity. The battery mentioned in this application may, for example, be a battery module, a battery pack, or the like. A battery typically includes a casing that encloses one or more battery cells. The casing can prevent liquids or other foreign matter from interfering with the charging or discharging of the battery cell.

[0079] The battery cell contains an electrode assembly and an electrolyte. The electrode assembly comprises a positive electrode plate, a negative electrode plate, and a separator. The battery cell's operation is primarily based on the migration of metal ions between the positive and negative electrode plates. The positive electrode plate contains a current collector for the positive electrode and an active material layer for the positive electrode. The active material layer for the positive electrode is applied to the surface of the positive electrode current collector. The positive electrode current collector includes a current collection section for the positive terminal and a positive terminal tab. The area of ​​the positive electrode that collects the current is coated with the active material layer for the positive electrode, while the positive electrode terminal tab is free of such an active material layer.In a lithium-ion battery, for example, the positive electrode current collector can be made of aluminum, and the positive electrode's active material layer contains an active substance for the positive electrode, which can consist of lithium cobalt, lithium iron phosphate, ternary lithium, lithium manganate, or a similar compound. The negative electrode plate contains a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is applied to the surface of the negative electrode current collector. The negative electrode current collector comprises a negative electrode current collection section and a negative electrode terminal tab. The area of ​​the negative electrode that collects the current is coated with the negative electrode active material layer, while the negative electrode terminal tab is free of such an active material layer.The negative current collector can be made of copper, and the negative electrode active material layer comprises a negative electrode active substance such as carbon, silicon, and the like. Polypropylene (PP), polyethylene (PE), or similar materials can be used for the separator.

[0080] The battery cell also includes a housing for the electrode assembly and an electrode terminal located on the housing. The electrode terminal is configured to be electrically connected to the electrode assembly to enable charging and discharging. To facilitate assembly and ensure the battery cell's current capacity, it is typically connected to the terminal and electrode terminal of the electrode assembly via a current collection unit.

[0081] To reduce resistance and increase current, inventors generally weld the electrode terminal to the current collector. The developers noticed that if the current collector and electrode terminal are welded together first, and then the electrode terminal is mounted to the housing, metal particles generated during welding can adhere to the electrode terminal or the current collector and fall into the housing during installation. These metal particles can penetrate the separator of the electrode assembly, posing a risk of short circuit.

[0082] To reduce the amount of metal particles falling into the housing, the developers tried first mounting the electrode terminal to the housing and then welding the current collector and the electrode terminal together from the outside of the electrode terminal. This allows the housing to trap the metal particles and thus reduce their entry into the housing.

[0083] During welding, however, the developers discovered that the electrode terminal and current collector had to be melted from the outside of the electrode terminal. The electrode terminal is typically quite thick, resulting in high current requirements and significant heat generation during welding. This heat is then transferred to other components, such as the sealing element and the electrode assembly, potentially damaging them and creating safety hazards.

[0084] In view of this, the embodiments of this application offer a technical solution by providing a concave section at the electrode connection to reduce the thickness of the electrode connection section for welding with the current collector, thereby reducing the difficulty of welding, reducing the heat generated during welding, and increasing safety.

[0085] The technical solution described in the embodiments of this application is applicable to batteries and electrical devices that use a battery.

[0086] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electronic toys, power tools, or similar items. The vehicle can be a fossil fuel vehicle, a natural gas vehicle, or a renewable energy vehicle. The renewable energy vehicle can be a battery-powered electric vehicle, a hybrid electric vehicle, an extended-range electric vehicle, or similar. The spacecraft can be an aircraft, a rocket, a space shuttle, a spacecraft, and the like. The electrical toy can be a stationary or portable electrical toy, such as a game console, an electric toy car, an electric toy ship, or an electric toy airplane.The power tool may be an electric cutting tool, an electric grinding tool, an electric assembly tool, or an electric railway-specific tool, e.g., an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an electric impact drill, a concrete vibrator, and an electric planer. The embodiments of the present application do not constitute a particular limitation for the aforementioned power tools.

[0087] To simplify the description, the electrical device, which is a vehicle, is used as an example for describing the following embodiments.

[0088] Fig. Figure 1 shows a schematic structure diagram of a vehicle according to some embodiments of this application. As illustrated in Fig. In section 1, vehicle 1 is equipped with a battery 2, which can be located on the floor or at the front or rear of vehicle 1. Battery 2 can be configured to supply power to vehicle 1. For example, battery 2 can provide operating power to vehicle 1.

[0089] Vehicle 1 can also include a control unit 3 and a motor 4. The control unit 3 is configured to regulate the battery 2 so that it supplies power to the motor 4, for example, to meet the power requirements of vehicle 1 during starting, navigation, and driving.

[0090] In some embodiments of this application, the battery 2 can not only serve to supply the vehicle 1 with operating energy, but can also be used as a power source for the vehicle 1. In this case, it can completely or partially replace fossil fuels or natural gas to ensure the propulsion of the vehicle 1.

[0091] Fig. Figure 2 shows a schematic exploded view of a battery as used in some embodiments of the present application. As illustrated in Fig. 2 The battery 2 comprises a housing 5 and a battery cell (not shown in Fig. 2), and the battery cell is housed in box 5.

[0092] The housing 5 is designed to accommodate the battery cell. Furthermore, the housing 5 can have various structures. In some embodiments, the housing 5 can consist of a first housing section 5a and a second housing section 5b. The first housing section 5a and the second housing section 5b are aligned such that together they enclose a receiving space 5c for housing the battery cell. The second housing section 5b can be a hollow structure with an opening at one end, while the first housing section 5a can be designed as a plate-shaped structure. The first housing section 5a covers the opening of the second housing section 5b to form the housing 5 with the receiving space 5c.Alternatively, both the first and second housing sections 5a and 5b can be hollow structures with an opening at the end, the opening of the first housing section 5a engaging with the opening of the second housing section 5b to form the housing 5 with the receiving chamber 5c. Naturally, the first housing section 5a and the second housing section 5b can have different shapes, such as cylinders and cuboids.

[0093] To optimize the airtightness after the connection of the first housing section 5a and the second housing section 5b, a sealing element, such as a sealing rubber and a sealing ring, can also be provided between the first housing section 5a and the second housing section 5b.

[0094] Assuming that the first housing section 5a fits on top of the second housing section 5b, the first housing section 5a can also be referred to as the upper cover and the second housing section 5b can also be referred to as the lower housing section.

[0095] The battery 2 can consist of one or more battery cells. Provided that a plurality of battery cells are available, the plurality of battery cells can be connected in series, parallel, or series-parallel, where series-parallel means a combination of series and parallel connections of several battery cells. The plurality of battery cells can be connected directly in series, parallel, or a mixed configuration (series-parallel), and this entire arrangement is then housed in the casing 5. Alternatively, the battery can also be constructed such that several battery cells are first connected in series, parallel, or a mixed configuration to form a battery module 6. Subsequently, several of these battery modules 6 are again connected in series, parallel, or a mixed configuration to form the complete battery housed in the casing 5.

[0096] Fig. Figure 3 shows a schematic structure diagram of a battery module. Fig. 2.

[0097] In some embodiments, such as in Fig. As shown in Figure 3, there is a plurality of battery cells 7, and the plurality of battery cells 7 are connected in series, parallel, or series-parallel to form the battery module 6. Several battery modules 6 are then connected in series, parallel, or series-parallel to form a whole that is housed in the casing.

[0098] All battery cells 7 in the battery module 6 can be electrically connected to each other via a busbar 8, such that the battery cells 7 in the battery module 6 are arranged in series, parallel, or series-parallel. One or more busbars n can be present, and each busbar 8 is configured to electrically connect at least two battery cells.

[0099] Fig. Figure 4 shows a schematic exploded view of a battery cell as used in some embodiments of the present application; Fig. Figure 5 shows a schematic cross-sectional view of a battery cell according to some embodiments of this application; Fig. Figure 6 shows an enlarged partial diagram of the battery cell Fig. 5; Fig. Figure 7 shows an enlarged schematic representation of Block B in Fig. 6; and Fig. Figure 8 shows an enlarged schematic representation of circle C in Fig. 7.

[0100] As illustrated in Fig. 4 to Fig. Figure 8 shows the battery cell 7 in some embodiments of this application comprising an electrode assembly 10, a housing 20, an electrode terminal 30, and a current collector 40. The electrode assembly 10 includes a first terminal 11. The housing 20 serves to accommodate the electrode assembly 10. The electrode terminal 30 is located in the housing 20 and comprises a first concave section 31 and a connecting section 32 at the base of the first concave section 31. The current collector 40 is connected to the first terminal 11 and welded to the connecting section 32.

[0101] The electrode assembly 10 comprises a first electrode plate and a second electrode plate exhibiting opposite polarities. One of the two electrode plates is positive and the other is negative. For example, the electrode assembly 10 generates electrical energy through oxidation and reduction reactions during the intercalation / deintercalation of ions in the positive and negative electrode plates. Furthermore, the electrode assembly 10 can optionally include a separator designed to isolate the first electrode plate from the second electrode plate.

[0102] In some embodiments, the first electrode plate, the second electrode plate, and the separator are each configured as strips, and the first electrode plate, the second electrode plate, and the separator are wound together around the central axis A to form a winding structure. The winding structure may have a cylindrical structure, a flat structure, or another shape. In some other examples, the electrode assembly 10 may comprise a composite structure that includes the laminated connection of the first electrode plate, the separator, and the second electrode plate.

[0103] The first connection tab 11 can be part of the first electrode plate, which is not coated with any active material layer. The first connection tab 11 can be a positive or a negative electrode tab.

[0104] The housing 20 has a hollow structure in which a space for receiving the electrode assembly 10 has been formed. The housing 20 can have various shapes and sizes, e.g., cuboid, cylindrical, or hexagonal prism. The housing shape 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, a cylindrical housing can be selected; and if the electrode assembly 10 has a cuboid structure, a cuboid housing can be selected. Both the electrode assembly 10 and the housing 20 can optionally be cylindrical.

[0105] The housing 20 can be made of various materials, such as copper, iron, aluminum, stainless steel and aluminum alloys, which are not particularly restricted in the embodiments of this application.

[0106] The case 20 can be positively charged, negatively charged, or uncharged.

[0107] The electrode terminal 30 can be used as the output electrode of battery cell 7, which can electrically connect battery cell 7 and an external circuit to enable charging and discharging of battery cell 7. Optionally, electrode terminal 30 can be configured to be connected to the busbar to establish an electrical connection between battery cells 7.

[0108] The electrode connection 30 can be attached to the housing 20 in an insulated manner or electrically connected to the housing 20. The embodiments of this application do not constitute a limitation, provided that the positive electrode plate and the negative electrode plate are not connected.

[0109] The first concave section 31 can be recessed from a side of the electrode terminal 30 facing away from the electrode assembly 10 in a direction facing the electrode assembly 10, or it can be recessed from a side of the electrode terminal 30 facing the electrode assembly 10 in a direction facing away from the electrode assembly 10.

[0110] The connecting section 32 is part of the electrode connection 30, which corresponds to the underside of the first concave section 31.

[0111] The current collector 40 electrically connects the first terminal 11 to the first electrode terminal 30. The embodiments of this application do not restrict the type of connection between the first terminal 11 and the current collector 40. The current collector 40 can, for example, be connected to the first terminal 11 by welding, pressing, or gluing.

[0112] The current collector 40 and the connecting section 32 are joined together by welding. For example, the current collector 40 and the connecting section 32 are joined by laser welding.

[0113] In this embodiment of this application, the first concave section 31 is provided at the electrode connection 30 to reduce the thickness of the connection section 32, thereby reducing the welding power required to weld the connection section 32 and the current collector element 40, reducing the heat generated, reducing the risk of burning other components, and increasing safety.

[0114] In some embodiments, the electrode assembly 10 comprises a main body 12, a first terminal 11, and a second terminal 13, wherein the first terminal 11 and the second terminal 13 project from the main body 12. The first terminal 11 is part of the first electrode plate, which is not coated with any active material layer, and the second terminal 13 is part of the second electrode plate, which is not coated with any active material layer.

[0115] The first terminal 11 and the second terminal 13 can protrude from the same side of the main body 12 or from opposite sides. For example, the first terminal 11 is located at an end of the electrode assembly 10 facing the electrode terminal 30, and the second terminal 13 is located at an end of the electrode assembly 10 facing away from the electrode terminal 30.

[0116] In some embodiments, the first terminal lug 11 is wound in several turns around the central axis A of the electrode assembly 10, meaning that the first terminal lug 11 comprises several turns of lug layers. After completion of the winding, the first terminal lug 11 is generally cylindrical, and a gap exists between two adjacent lug layers. In this embodiment of this application, the first terminal lug 11 can be treated to reduce the gap between the lug layers in order to facilitate the connection between the first terminal lug 11 and the current collector 40. For example, in this embodiment of this application, the first terminal lug 11 can be shaped so that end regions of the first terminal lug 11 facing away from the main body 12 can be joined together.As a result of the forming process, a dense end surface forms at the end of the first connecting tab 11 facing away from the main body 12. This reduces the gap between the tab layers and simplifies the connection between the first connecting tab 11 and the current collector 40. Alternatively, in this embodiment of this application, a conductive material can be filled between two adjacent tab layers to further reduce the gap between the tab layers.

[0117] In some embodiments, the second terminal lug 13 is wound in several turns around the central axis A of the electrode assembly 10, meaning that the second terminal lug 13 comprises several turns of lug layers. For example, the second terminal lug 13 was also shaped to reduce the distance between the lug layers of the second terminal lug 13.

[0118] The central axis A of the electrode assembly 10 is a virtual straight line. The first electrode plate, the second electrode plate, and the separator can be wound on the basis of the central axis A.

[0119] In some embodiments, the housing 20 comprises a cylinder 21 and a cover 22 connected to the cylinder 21. The cylinder 21 is arranged around the circumference of the electrode assembly 10. The cover 22 is provided with an opening 221 for the electrode guide. The electrode connection 30 is secured in the electrode guide opening 221.

[0120] The cover 22 and the cylinder 21 may have been manufactured as a single piece, so that the housing 20 is a single component. Of course, the cover 22 and the cylinder 21 may also consist of two separate parts, which are then joined together by welding, riveting, gluing, or similar methods.

[0121] The electrode feedthrough opening 221 extends through the cover 22 to dissipate the electrical energy in the electrode assembly 10 from the housing 20.

[0122] The central axis A is a virtual straight line that passes through the electrode feedthrough opening 221. The central axis A of the electrode assembly 10 may coincide with the axis of the electrode feedthrough opening 221, but it does not have to.

[0123] The electrode connection 30 is designed to fit the electrode feedthrough opening 221 in order to completely seal the electrode feedthrough opening 221. The electrode connection 30 may, but need not, protrude into the electrode feedthrough opening 221. The electrode connection 30 is attached to the cover 22. The electrode connection 30 can be attached to the outside of the cover 22 or protrude through the electrode feedthrough opening 221 into the interior of the housing 20.

[0124] In some embodiments, the cover 22 and the cylinder 21 were manufactured as a single piece. This eliminates the need for the joining process between the cover 22 and the cylinder 21.

[0125] When the cover 22 and the cylinder 21 are electrically connected to a positive or a negative electrode of the electrode assembly 10, the resistance at the connection point between the cover 22 and the cylinder 21 is low precisely because the connection between the cover 22 and the cylinder 21 has an integrated structure, thus improving the current capacity. The cover 22 can be designed to be connected to an external component (for example, the busbar). If the battery cell is subjected to an external impact, the external component can pull the cover 22 along with it, subjecting the joint between the cover 22 and the cylinder 21 to a force. In the described technical solution, the cover 22 and the cylinder 21 are manufactured as a single piece.This serves to improve the connection strength between the cover 22 and the cylinder 21 and thus reduce the risk of failure at the connection point between the cover 22 and the cylinder 21.

[0126] In some embodiments, the housing 20 can be formed by a stretching process.

[0127] In some versions, the housing 20 has an opening 211 at one end facing away from the electrode connection 30. The battery cell 7 also contains a cover plate 50 to seal this opening 211.

[0128] More precisely, the cylinder 21 has an opening at the end opposite the cover 22. The cover plate 50 closes the opening of the cylinder 21 and thus seals it. The cover plate 50 can consist of various structures; for example, the cover plate 50 may be a plate structure.

[0129] In some embodiments, the cover plate 50 can be a circular cover plate, a rectangular cover plate, a square cover plate, a hexagonal cover plate, or other shaped cover plates.

[0130] In some embodiments, the cover plate 50 is welded to the cylinder 21.

[0131] In some embodiments, the cover 22 is circular and the electrode assembly 10 is cylindrical, and the central axis A coincides with the axis of the electrode feedthrough opening 221. In this embodiment, it is not necessary for the central axis A to coincide completely with the axis of the electrode feedthrough opening 221, and a deviation between the two is permissible by the method.

[0132] In this embodiment, the electrode feedthrough opening 221 is generally located in the center of the cover 22, and accordingly, the electrode terminal 30 is also located in the center of the cover 22. When several battery cells 7 are assembled into a group, the positioning accuracy requirement of the electrode terminal 30 can be reduced to simplify the assembly process.

[0133] For example, the axis of the electrode feedthrough opening 221 coincides with the axis of the cover 22. Furthermore, the cover 22 is an annular structure arranged around the axis of the electrode feedthrough opening 221.

[0134] For example, the electrode connection axis 30 coincides with the axis of the electrode feedthrough opening 221.

[0135] In some other embodiments, the cover 22 can also be rectangular, and the electrode assembly 10 is flat. The electrode feedthrough opening 221 can be arranged near one end of the cover 22 in the longitudinal direction of the electrode feedthrough opening 221.

[0136] In some embodiments, the electrode assembly 10 also comprises a second terminal 13 with a polarity opposite to that of the first terminal 11, the second terminal 13 being arranged around the central axis A of the electrode assembly 10. The first terminal 11 is located at an end of the electrode assembly 10 facing the electrode terminal 30, the second terminal 13 is located at an end of the electrode assembly 10 facing away from the electrode terminal 30, and the second terminal 13 is electrically connected to the housing 20.

[0137] The housing 20 can directly serve as an output electrode for the battery cell 7. This eliminates the need for a conventional electrode connection and simplifies the design of the battery cell 7. When multiple battery cells 7 are assembled into a group, the housing 20 can be electrically connected to the busbar. This not only increases the current flow area but also allows for a more flexible busbar design.

[0138] In some embodiments, the second terminal 13 is a negative electrode terminal, and the substrate material of the housing 20 is steel. The housing 20 is electrically connected to the negative electrode terminal, i.e., the housing 20 is at a low potential. In this low-potential state, the steel housing 20 is largely resistant to corrosion by the electrolyte.

[0139] In some versions, the cylinder 21 is designed to connect the second connecting lug 13 and the cover 22 in such a way that an electrical connection is established between the second connecting lug 13 and the cover 22.

[0140] The cylinder 21 can be directly electrically connected to the second terminal 13 or electrically connected to the second terminal 13 via other components. For example, the second terminal 13 is electrically connected to the cylinder 21 via the cover plate 50.

[0141] The cover 22 and the electrode terminal 30 have opposite polarities. In this case, one of the covers 22 and the electrode terminal 30 can be used as the positive output electrode of the battery cell 7, and the other as the negative output electrode of the battery cell 7. In this embodiment, the positive and negative output electrodes are located on the same side of the battery cell 7, which simplifies the connection process between multiple battery cells 7.

[0142] In this application embodiment, the electrode feedthrough opening 221 is created after the housing 20 has been stretched and shaped.

[0143] The developers attempted to deform the open end of the cylinder so that it would fold inwards, forming a crimped edge that would press the cover plate against it for fixation. They mounted the electrode terminal on the cover plate and used the crimped structure and the electrode terminal as the two output electrodes of the battery cell. However, the larger the dimensions of the crimped structure, the greater the risk of it wrinkling and creasing after forming. Once the crimped structure wrinkles and develops folds, the surface becomes uneven. This results in poor weldability when welding the crimped structure to an external busbar. Therefore, the size of the crimped structure is relatively limited, leading to insufficient current capacity of the battery cell.

[0144] In this embodiment, the electrode feedthrough opening 221 for attaching the electrode terminal 30 in the cover 22 is produced by a perforation process. This positions the positive and negative output electrodes at the end of the battery cell 7 facing away from the cylinder opening 21. The cover 22 is formed during the molding of the housing 20. Flatness is maintained even after the electrode feedthrough opening 221 is opened, and the connection strength between the cover 22 and the busbar remains secure. Furthermore, the flatness of the cover 22 is not limited by its own dimensions, allowing the cover 22 to be larger, thereby improving the current capacity of the battery cell 7.

[0145] In some embodiments, the current collector 40 is welded to the connecting section 32 to form a first weld section W1. In the thickness direction of the connecting section 32, the first weld section W1 extends from the side of the connecting section 32 facing away from the current collector 40 at least into the interior of the current collector 40.

[0146] During welding, the connecting section 32 and the current collector 40 partially melt, creating a molten pool. This molten pool eventually solidifies to form the first weld section W1. For example, if the electrode assembly 10 and the current collector 40 are inserted into the housing 20 and the current collector 40 is pressed against the connecting section 32, an external welding device can weld the connecting section 32 and the current collector 40 from the side of the connecting section 32 opposite the current collector 40, thus forming the first weld section W1. The first weld section W1 lies freely on a surface of the connecting section 32 facing away from the current collector 40.

[0147] The embodiments of this application do not impose any special restrictions regarding the shape, position, depth, and quantity of the first weld section W1. For example, the first weld section W1 can be straight, C-shaped, annular, spiral, V-shaped, or other forms. The first weld section W1 can be present in one or more sections.

[0148] The first weld section W1 can pass through the current collector 40. For example, the first weld section W1 passes through the current collector 40 and the connecting section 32, and the first weld section W1 lies freely on the surface of the current collector 40 facing away from the connecting section 32. Of course, the first weld section W1 may not pass through the current collector 40, i.e., the first weld section W1 may not lie freely on the surface of the current collector 40 facing away from the connecting section 32.

[0149] The first welding section W1 extends from the connecting section 32 to the inside of the current collector 40 in order to connect the current collector 40 and the connecting section 32, to reduce the contact resistance between the current collector 40 and the electrode terminal 30 and to improve the current capacity.

[0150] In some designs, the first welding area W1 in the thickening direction X of the connection section 32 does not protrude above the current collecting element surface 40 facing away from the connection section 32.

[0151] In the previously described technical solution, the first weld section W1 is arranged at a predetermined distance from the current collector surface 40 facing away from the connection section 32. This serves to prevent the current collector 40 from melting through, to reduce the risk of metal particle formation on the surface of the connection section 32 facing away from the current collector 40, and to increase safety.

[0152] In some embodiments, the housing 20 comprises a cylinder 21 and a cover 22 connected to the cylinder 21. The cylinder 21 is arranged around the circumference of the electrode assembly 10. The cover 22 is provided with an opening 221 for the electrode guide. The electrode connection 30 is secured in the electrode guide opening 221. The first weld section W1 and the cover 22 are both annular; the outer diameter of the cover 22 is D0, and the inner diameter of the first weld section W1 is D1. D1 and D0 satisfy the following conditions: 0.1 ≤ D1 / D0 ≤ 0.6.

[0153] The first weld section W1 can have a closed or an open structure. In other words, the first weld section W1 can be a semicircular ring or a full ring.

[0154] D0 correlates positively with the diameter of the electrode assembly 10. The larger D0 is, the higher the capacity of the electrode assembly 10 and the greater the current flow area required by the battery cell 7 for the first welding section W1. The smaller D1 is, the smaller the circumference of the first welding section W1 and the smaller the current flow area of ​​the first welding section W1. If D1 / D0 is too small, D1 is relatively small because D0 is relatively large. Consequently, the current flow area of ​​the first welding section W1 is insufficient, leading to significant overheating during charging and discharging. This makes it difficult to meet the requirements of the battery cell 7 for current capacity and the limitation of temperature rise during fast charging.The developers have demonstrated through comprehensive studies and various experiments that, at D1 / D0 ≥0.1, the requirements of battery cell 7 for current capacity and temperature rise control can be met.

[0155] The larger D1 is, the larger the dimensions of the electrode feedthrough opening 221 and the smaller the cover area 22. The smaller D0 is, the smaller the cover area 22. If D1 / D0 is too large, D1 is relatively large because D0 is relatively small. This causes the cover 22 to deform easily when the battery cell 7 vibrates, potentially creating safety hazards. The cover 22 can be used as the output electrode of the battery cell 7, which is connected to a busbar. If D1 / D0 is too large, the cover contact areas 22 to the busbar and the current-carrying area between the cover 22 and the busbar are relatively small. The heat generated at the connection point between the cover 22 and the busbar is correspondingly high, making it difficult to meet the battery cell 7's requirements for current carrying capacity and temperature rise control during fast charging.Through intensive studies and numerous experiments, the developers determined that with a ratio D1 / D0 ≤ 0.6, the requirements of battery cell 7 for current capacity and temperature rise control can be met, and the safety of battery cell 7 is increased.

[0156] D1 / D0 can be 0.1, 0.2, 0.3, 0.4, 0.5 or 0.6.

[0157] In some embodiments, the developers have found through extensive studies and experiments that with a ratio of 0.2≤D1 / D0≤0.4, the battery cell 7 better meets its requirements for current capacity and temperature rise limitation, and the safety of the battery cell 7 can be improved.

[0158] In some embodiments, D1 lies in a range of 5 mm to 14 mm.

[0159] If D1 is too small, the current flow area of ​​the first weld section W1 is insufficient, and the first weld section W1 generates a significant amount of heat during charging and discharging, making it difficult to meet the current capacity and temperature rise control requirements of battery cell 7 during fast charging. If D1 is too large, the current flow area between cover 22 and the busbar is insufficient, and the heat generated at the junction between cover 22 and the busbar is relatively high. Through intensive studies and numerous experiments, the developers determined that setting D1 within a range of 5 mm to 14 mm allows the current capacity and temperature rise control requirements of battery cell 7 to be met.

[0160] D1 can optionally be 5 mm, 7 mm, 9 mm, 10 mm, 12 mm or 14 mm.

[0161] In some embodiments, in the thickening direction X of the connection section 32, the dimension of the first weld section W1 h, the area thickness of the connection section 32 for welding with the current collector element 40 is d0, and d0 and h satisfy conditions 1 <h / d0≤1,5.

[0162] The first weld section W1 is ring-shaped. Due to process errors, different areas of the first weld section W1 may exhibit different weld penetration depths in the thickening direction X. h could be a dimension of an area of ​​the first weld section W1 that has the shallowest weld penetration depth in the thickening direction X.

[0163] In some examples, the connecting section 32 exhibits a flat plate structure of uniform thickness, any part of the connecting section 32 can be used for welding to the current collector 40, and d0 is the thickness of the connecting section 32. In some other embodiments, the connecting section 32 is a structure of unequal thickness. A region of the connecting section 32 with a reduced thickness can serve as the welding area for the current collector 40, thereby reducing the required welding current and heat generation. For example, a groove can be machined into the connecting section 32 to reduce the local thickness, and a region of the connecting section 32 corresponding to the groove can be used as the welding area for the current collector 40.

[0164] Provided that h / d0 ≤ 1, the penetration depth of the first weld section W1 is shallow. Because the first weld section W1 is formed integrally with the connecting section 32, a cold solder joint is created, making it difficult for the first weld section W1 to effectively connect the current collector element 40 and the connecting section 32. If d0 is constant, the power required for welding increases with increasing h, and consequently, so does the heat generated during welding. If h is too large, the high temperature generated during welding can easily damage the components in the area of ​​the electrode connection 30, creating potential safety hazards.

[0165] Through intensive studies and numerous experiments, the developers were able to determine that it is possible to reduce the heat generated during welding and the difficulties involved in welding if 1 <h / d0≤1.5 ist und dabei die Verbindung zwischen dem Stromsammelelement 40 und dem Verbindungsabschnitt 32 erhalten bleibt.

[0166] h / d0 can optionally be 1.05, 1.1, 1.2, 1.3, 1.4 or 1.5.

[0167] In some embodiments, the thickness of a region of the current collecting element 40 for welding to the connecting section 32 d1, and d0 and d1 satisfy 0.5≤d1 / d0≤1.2.

[0168] The region of the current collector element 40 intended for welding to the connecting section 32 is that area of ​​the current collector element 40 which is adjacent to the connecting section 32.

[0169] The smaller d1 is at a constant d0, the more easily the current collector element 40 melts through during welding and the more easily the high-temperature particles generated during welding fall into the battery cell 7; and the larger d1 is, the larger the space occupied by the current collector element 40, the higher the weight and the lower the energy density of the battery cell 7.

[0170] Based on intensive studies and numerous experiments, the developers have found that at 0.5≤d1 / d0≤1.2 the risk of melting of the current collecting element 40 and loss of energy density of the battery cell 7 can be reduced.

[0171] d1 / d0 can optionally be 0.5, 0.7, 0.9, 1.0 or 1.2.

[0172] In some embodiments, D0 lies in a range of 0.4 mm to 1.2 mm.

[0173] The smaller d0 is, the lower the current capacity of the connection section 32. If d0 is too small, the connection section 32 may not be able to meet the current capacity requirements of the battery cell 7 and the temperature rise control during fast charging. The larger d0 is, the greater the power required for welding and the greater the heat generated during welding. If d0 is too large, the high temperature generated during welding can easily damage the components in the area of ​​the electrode terminal 30, creating potential safety hazards.

[0174] Through intensive studies and numerous experiments, the developers have found that if d0 is set in a range of 0.4 mm to 1.2 mm, the requirements of battery cell 7 for current capacity and temperature rise control can be met, and the heat generated during welding can be reduced, thus increasing safety.

[0175] d0 can optionally be 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm or 1.2 mm.

[0176] Through intensive studies and numerous experiments, the developers optionally determined that setting d0 in the range of 0.6 mm to 1.0 mm allows for better fulfillment of the requirements of battery cell 7 regarding current capacity and temperature rise control. Furthermore, it reduces the heat generated during welding, thus increasing safety.

[0177] In some embodiments, d1 is in the range of 0.2 mm to 0.6 mm. Optionally, d1 is in the range of 0.3 mm to 0.5 mm.

[0178] In some embodiments, at least part of the first terminal tab 11 is located on a side of the current collecting element 40 facing away from the electrode terminal 30 and supports the current collecting element ab 40.

[0179] The first connecting tab 11 can support the current collector 40 in such a way that the current collector 40 sits correctly on the connecting section 32. The first connecting tab 11 can restrict the relative movement of the current collector 40 to the connecting section 32 during vibrations of the battery cell 7. This reduces the stress on the first weld section W1 and reduces the risk of cracking at the first weld section W1.

[0180] During the assembly of the battery cell 7, the current collector 40 can be supported by the first terminal tab 11 in such a way that the current collector 40 lies close to the connection section 32 and the relative displacement between the current collector 40 and the connection section 32 is reduced during welding, thereby reducing the risk of a cold solder joint.

[0181] In some embodiments, a first section 111 of the first connecting lug 11 is arranged on the side of the connecting section 32 facing away from the first concave section 31 and is intended to support a part of the current collecting element 40 that is opposite the connecting section 32.

[0182] In the thickening direction X of the connecting section 32, the first section 111 is arranged opposite the connecting section 32. In other words, this means that the first section 111 belongs to the first connecting lug 11 and overlaps with the connecting section 32 in the thickening direction X.

[0183] The first section 111 can support the portion of the current collector 40 opposite the connection section 32 to ensure that the current collector 40 rests firmly against the connection section 32, thereby reducing the risk of cold solder joints. During welding, the first section 111 can also reduce the deformation of the current collector 40 and optimize its shape.

[0184] In some embodiments, a second section 112 of the first connecting lug 11 encloses the perimeter of the first section 111 and is designed to support an area of ​​the current collecting element 40 which is not located opposite the connecting section 32.

[0185] The second section 112 is part of the first connecting tab 11 that does not overlap with the connecting section 32 in the thickening direction X. For example, the second section 112 represents a ring-shaped structure.

[0186] The arrangement of the second section 112 increases the surface area of ​​the first terminal lug 11, which supports the current collector 40. This results in improved support for the first terminal lug 11, reduced pressure between the first terminal lug 11 and the current collector 40, and a reduced risk of the first terminal lug 11 being crushed. During welding of the connection section 32 and the current collector 40, the second section 112 can support the current collector 40, thereby reducing the relative displacement between the current collector 40 and the connection section 32 during welding and reducing the risk of a cold solder joint.

[0187] In some embodiments, the first connecting lug 11 in the thickening direction X of the connecting section 32 may not be integrally opposite the connecting section 32. In other words, the first connecting lug 11 may only include the second cut 112.

[0188] In some embodiments, the second section 112 is welded to the current collector element 40 to form a third weld area W3.

[0189] During the assembly of the battery cell 7, the second section 112 of the first terminal 11 of the electrode assembly 10 can first be welded to the current collector 40. Subsequently, the electrode assembly 10 and the current collector 40 are inserted into the housing 20. Specifically, when welding the second section 112 and the current collector 40, the current collector 40 can first be pressed against the flattened end face of the first terminal 11, and an external welding device then shines a laser onto a surface of the current collector 40 facing away from the first terminal 11. The current collector 40 and the second section 112 of the first terminal 11 are welded together by the laser.

[0190] The shape of the third weld section W3 can be straight, C-shaped, ring-shaped, spiral, V-shaped, or other shapes, which are not limited in the embodiments. The third weld section W3 can be manufactured in one or more sections.

[0191] The third welding section W3 reduces the contact resistance between the current collecting element 40 and the second section 112, thereby increasing the current capacity.

[0192] In some embodiments, the current collector element 40 has a convex section 41 on one of the sides facing the first terminal lug 11, and the convex section 41 is welded to the second section 112 to form the third welded section W3.

[0193] During the assembly of the current collector 40 and the electrode assembly 10, the convex section 41 of the current collector 40 is first pressed against the second section 112, and then the convex section 41 and the second section 112 are welded together. The convex section 41 can be better adapted to the second section 112, thereby reducing the risk of a poor weld.

[0194] In some embodiments, the convex section 41 can be pressed against the second section 112 and recessed into the second section 112.

[0195] In some embodiments, the other sections of the current collecting element 40, with the exception of the convex section 41, generally consist of flat plate structures.

[0196] According to some embodiments, the current collector 40 has a corresponding second concave section 42 at the location of the convex section 41. This second concave section 42 is recessed in the direction of the first terminal lug 11, specifically from the side of the current collector 40 facing away from the first terminal lug 11. A transition section is located between the underside of the second concave section 42 and the upper side of the convex section 41. This transition section is welded to the second section 112, thus forming the third weld section W3. To reduce the thickness of the transition section, a second concave section 42 can be provided. This serves to reduce the welding power required to weld the transition section and the second section 112, to decrease the heat generated, and to reduce the risk of the electrode assembly 10 burning.

[0197] The third weld section W3 is formed by welding, with an uneven surface. In this embodiment, the second concave section 42 is designed such that the surface of the third weld section W3 is recessed relative to the surface of the current collector element 40 facing away from the first terminal 11. This insulates the third weld section W3 from other components (such as the electrode terminal 30).

[0198] In certain embodiments, a retaining plate (not shown) may be present in the second concave section 42. This retaining plate is designed to cover the third weld section W3 and to fix the residual metal particles there, thereby reducing the risk of a short circuit caused by falling metal particles into the electrode assembly 10. The retaining plate may be an insulating patch, an insulating adhesive layer, or another structure.

[0199] Fig. Figure 9 shows a schematic representation of the terminal body of an electrode terminal of a battery cell according to certain embodiments of this application.

[0200] As illustrated in Fig. 9, in some embodiments the first weld section W1 represents an open structure, and the central angle α of the first weld section W1 is in the range of 180° to 330°. α is positively correlated with the current flow area of ​​the first weld section W1. The smaller α is, the smaller the current flow area of ​​the first weld section W1 and the higher the heat generation when current flows through the first weld section W1. In this embodiment of the application, α is set in the range of 180° to 330° so that the first weld section meets the battery cell's requirements for current capacity and temperature rise control.

[0201] The first weld section W1 has an open structure, whereby an unwelded area between the two ends of the first weld section W1 in the circumferential direction can relieve the welding stresses and reduce the stress concentration.

[0202] Fig. Figure 10 shows a schematic representation of the terminal body of an electrode terminal of a battery cell according to certain embodiments of this application.

[0203] As illustrated in Fig. 10. In some embodiments, the first weld section W1 forms a closed structure. In other words, this means that the central angle of the first weld section W1 is 360°. This embodiment of the application increases the weld area and improves the weld strength and current capacity of the first weld section.

[0204] Fig. Figure 11 shows a schematic structure diagram of an electrode assembly and a current collection element of a battery cell according to some embodiments from this application.

[0205] See Fig. 6 to Fig. 11 together. In certain implementations, the first terminal 11 is positioned around the central axis A of the electrode assembly 10, with a cross-section of the first terminal 11 perpendicular to the central axis being annular. The outer radius of the first terminal 11 is R, the minimum distance between the third weld section W3 and the central axis A in the radial direction of the first terminal 11 is D2, and R and D2 satisfy 0.2 ≤ D2 / R ≤ 0.8.

[0206] It is not absolutely necessary that the cross-section of the first connecting flag 11 has an absolute ring shape perpendicular to the central axis A; a deviation is permitted.

[0207] R correlates positively with the diameter of the electrode assembly 10. As R increases, the current generated by the electrode assembly 10 also increases, which in turn places a higher demand on the current-flow area of ​​the battery cell 7. A portion of the current collector element 40 near the central axis A can be used for welding to the connecting section 32; and the smaller the diameter D2, the smaller the area of ​​the current collector element 40 that can be welded to the connecting section 32, and the smaller the current-flow area between the current collector element 40 and the connecting section 32. If D2 / R is too small, R is relatively large because D2 is relatively small. The result is an insufficient current-flow area between the current collector element 40 and the connecting section 32.This results in a significant amount of heat being generated at the weld point between the current collector element 40 and the connection section 32 during charging and discharging. This poses a problem because the requirements of the battery cell 7 regarding current carrying capacity and temperature rise control during fast charging are difficult to meet.

[0208] The first terminal 11 has several layers, each surrounding the central axis A. The layers of the terminal 11 are stacked radially on top of each other. The current from a layer directly connected to the third weld section W3 can be conducted directly to the current collector 40 via this third weld section W3. In contrast, the current from a layer not connected to the third weld section W3 must first be conducted to a directly connected layer before also reaching the current collector 40 via the third weld section W3. This results in a difference in the conductor paths between the numerous layers and a first wall. If the difference is too large, polarization problems can occur.

[0209] If D2 / R is too large, the distance between the third weld section W3 and the outermost flash layer is too great. This results in the current path between the outermost flash layer and the electrode terminal 30 deviating significantly from that between the innermost flash layer and the electrode terminal 30. This, in turn, causes an irregular current density at the first electrode plate of the electrode assembly 10 and an increase in its internal resistance.

[0210] The developers have demonstrated through comprehensive studies and various experiments that the requirements of battery cell 7 for current capacity and temperature rise control can be met when D2 / R≥0.2.

[0211] The larger D2 is, the more outer the flash layer directly connected to the third weld section W3. If D2 is too large, the number of flash layers connected to the third weld section W3 is comparatively small. Furthermore, the distance between the third weld section W3 and the innermost flash layer is too great. This results in the current path between the outermost flash layer and the electrode terminal 30 deviating significantly from that between the innermost flash layer and the electrode terminal 30. The result is an inhomogeneous current density at the first electrode plate and an increase in internal resistance.

[0212] Through intensive studies and numerous experiments, the developers discovered that with a D2 / R ratio ≤ 0.8, the difference in current paths between the sections of the first terminal 11 at different positions and the electrode terminal 30 is reduced. This leads to a more uniform current density distribution of the first electrode plate of the electrode assembly 10, a reduction in internal resistance, and an increase in current capacity.

[0213] D2 / R can optionally be 0.2, 0.3, 0.5, 0.7 or 0.8.

[0214] Based on extensive studies and numerous experiments, the developers found that in some embodiments the current capacity of battery cell 7 can be optimized and its temperature rise reduced if D2 and R are in the range of 0.2≤D2 / R≤0.5.

[0215] In some embodiments, D2 lies in a range of 3.5 mm to 10 mm.

[0216] If D2 is too small, the current flow area between the current collector 40 and the connection section 32 is insufficient, and significant heat is generated at the weld point between the current collector 40 and the connection section 32 during charging and discharging. This makes it difficult to meet the current capacity and temperature rise control requirements of battery cell 7 during fast charging. The developers have demonstrated through comprehensive studies and various experiments that the current capacity and temperature rise control requirements of battery cell 7 can be met when D2 ≥ 3.5 mm.

[0217] If D2 is too large, the number of cap layers connected by the third weld section W3 is relatively small, and the distance between a cap layer near the central axis A and the third weld section W3 is too large, resulting in a relatively high internal resistance of the electrode assembly 10 and impairing the performance of the battery cell 7. Through intensive investigations and numerous experiments, the developers found that the internal resistance of the electrode assembly 10 can be reduced if D2 ≤ 10 mm, and that the charging and discharging performance of the battery cell 7 can be improved.

[0218] D2 can optionally be 3.5 mm, 4 mm, 5 mm, 7 mm, 8.5 mm or 10 mm.

[0219] In some embodiments, R lies in a range of 20 mm to 22.8 mm.

[0220] In some embodiments, the third welding section W3 is annular. The larger current flow area of ​​the annular third welding section W3 allows the current density of the first electrode plate to be distributed more evenly, the internal resistance to be reduced, and the current capacity to be increased.

[0221] In some embodiments, the diameter of the current collector element is 40 D3, the diameter of the first terminal lug is 11 D4, and D3 is smaller than D4.

[0222] D3 refers to the diameter of an outer edge of the current collector element 40, i.e., the outer diameter of the current collector element 40. D4 refers to the diameter of the outer edge of the first terminal lug 11, i.e., the outer diameter of the first terminal lug 11. For example: D4 = 2 × R.

[0223] The current collection element 40 has a smaller diameter, which saves the space occupied by the current collection element 40, reduces the weight of the current collection element 40 and increases the energy density of the battery cell 7.

[0224] In some embodiments, D3 and D4 correspond to 0.75≤D3 / D4≤0.97.

[0225] If D4 is constant and D3 is simultaneously too low, the distance between the outer area of ​​the first terminal 11 and the current collector 40 increases. This significantly lengthens the conductive path between the first terminal 11 and the current collector 40, resulting in a relatively high internal resistance of the electrode assembly 10 and thus negatively affecting the performance of the battery cell 7. Through intensive investigations and numerous experiments, the developers discovered that the internal resistance of the electrode assembly 10 can be reduced if D3 / D4 ≥ 0.75, and that the charging and discharging performance of the battery cell 7 can be improved.

[0226] Under the condition that D4 is constant and D3 has an excessive value, assembly errors lead to fluctuations in the coaxiality between the current collector 40 and the electrode assembly 10. This results in the current collector 40 protruding beyond the outer circumferential surface of the electrode assembly 10, making it difficult to insert the current collector 40 and the electrode assembly 10 into the housing. This negatively impacts assembly efficiency and the product defect rate. Through intensive studies and numerous experiments, the developers found that with D3 / D4 ≤ 0.97, the risk of the current collector 40 protruding from the outer circumferential surface of the electrode assembly 10 due to errors can be reduced, and assembly efficiency and the product defect rate can be improved.

[0227] D3 / D4 can optionally be 0.75, 0.8, 0.85, 0.9, 0.95 or 0.97.

[0228] In some embodiments, D3 is in the range of 35 mm to 44 mm. Through intensive studies and numerous experiments, the developers found that when D3 is set to a range of 35 mm to 44 mm, the internal resistance of the electrode assembly 10 can be reduced, the charging and discharging performance of the battery cell 7 can be improved, and the risk of the current collector element 40 protruding from the outer circumferential surface of the electrode assembly 10 due to defects can be reduced.

[0229] D3 can optionally be 35 mm, 38 mm, 40 mm, 41 mm, 43 mm or 44 mm.

[0230] Through intensive studies and numerous experiments, the developers found that in some embodiments the internal resistance of the electrode assembly 10 could be further reduced and the charging and discharging performance of the battery cell 7 improved if D3 was set to a range of 38 mm to 41 mm.

[0231] In some embodiments, the connecting section 32 has a groove 324 which is recessed from a first outer surface 322 of the connecting section 32 in the direction of the electrode assembly 10, and the first welding section W1 extends from the bottom wall of the groove 324 at least as far as the current collecting element 40.

[0232] The connecting section 32 has a first outer surface 322 and a first inner surface 321. These are located opposite each other in the thickening direction X of the connecting section 32, with the first inner surface 321 facing the current collector element 40 and the first outer surface 322 facing away from the current collector element 40. Optionally, the first outer surface 322 and the first inner surface 321 are both flat.

[0233] The groove 324 is recessed relative to the first outer surface 322 in a direction facing the current collector element 40. In this embodiment, the groove 324 is designed at the connecting section 32 such that a stepped structure is formed at the connecting section 32. A gap is located between the first outer surface 322 and the bottom wall of the groove 324.

[0234] The section between the bottom wall of the groove 324 and the first inner surface 321 can be an area of ​​the connection section 32 for welding to the current collector element 40. In other words, this means that the section between the bottom wall of the groove 324 and the first inner surface 321 is used for welding to the current collector element 40 to form the first weld section W1.

[0235] During the manufacture of the battery cell 7, an external device must interact with the connecting section 32. The surface of the first weld section W1 is uneven, and if the external device is pressed onto the first weld section W1, it is easily squeezed through it. In this embodiment, the provided groove 324 forms a gap between the first outer surface 322 and the bottom wall of the groove 324, allowing the first outer surface 322 to be designed to support the external device, separating it from the first weld section W1 and thus reducing the risk of damage to the external device from being squeezed.

[0236] The external device may be, for example, an electrolyte injection device, an air extraction device, a welding device, or other devices used for battery cell 7.

[0237] In some embodiments, the connecting section 32 is provided with a first through-hole 323, wherein the first through-hole 323 is designed to connect the space on the side of the connecting section 32 facing away from the electrode assembly 10 with the interior of the housing 20.

[0238] The first through-hole 323 extends through the connecting section 32 in the thickening direction X of the connecting section 32. The first through-hole 323 can be provided in one or more holes.

[0239] When the connecting section 32 and the current collector element 40 are welded together, the first feedthrough opening 323 can relieve the stress from the welding and reduce the risk of breakage of the connecting section 32.

[0240] During the formation of the battery cell 7, the first feedthrough opening 323 can be used in several formation processes. For example, the first feedthrough opening 323 can be used for electrolyte injection, formation, or other processes.

[0241] The first feedthrough opening 323 serves in particular to inject the electrolyte into the interior of the housing 20. If the process requires electrolyte injection, an electrolyte injection head of an electrolyte injection device is pressed against the connecting section 32. Subsequently, the electrolyte injection head injects electrolyte into the housing 20 via the first feedthrough opening 323.

[0242] During the formation of the battery cell 7, gas is generated in the housing 20, whereby the first through-hole 323 can also be used for connection to an external vacuum device in order to discharge the gas from the housing 20.

[0243] In some embodiments, the axis of the first feedthrough opening 323 coincides with the axis of the electrode feedthrough hole 221.

[0244] In some embodiments, the current collector element 40 is provided with a second through-hole 45. The second through-hole 45 is designed to be opposite the first through-hole 323, so that the electrolyte can flow through the second through-hole 45 into the interior of the housing 20.

[0245] The axial direction of the first through-hole 323 is parallel to the axial direction of the second through-hole 45. In the axial direction of the first through-hole 323, the projection of the first through-hole 323 overlaps at least partially with the projection of the second through-hole 45. The diameter of the second through-hole 45 is not limited in this embodiment and can be larger, equal to, or smaller than that of the first through-hole 323.

[0246] In this embodiment, the second through-hole 45 is provided opposite the first through-hole 323 on the current collector element 40. This serves to reduce blockage of the electrolyte by the current collector element 40 during the electrolyte injection process, so that the electrolyte can flow unhindered into the housing 20 and the penetration efficiency of the electrode assembly 10 can be improved.

[0247] In some embodiments, the overhang of the first through-hole 323 falls into the overhang of the second through-hole 45 in the axial direction of the through-hole 323. In this embodiment, it is possible to prevent the current collector element 40 from blocking the first through-hole 323, so that the electrolyte can flow smoothly into the housing 20.

[0248] The first through-hole 323 and the second through-hole 45 are arranged coaxially, the diameter of the second through-hole 45 being larger than that of the first through-hole 323.

[0249] In some embodiments, the electrode assembly 10 is configured as a winding structure. The electrode assembly 10 has a third through-hole 14 in the winding center, which extends through the entire electrode assembly 10. This third through-hole 14 is located opposite the first through-hole 323 and the second through-hole 45 to allow the electrolyte to flow through the third through-hole 14 into the interior of the electrode assembly 10.

[0250] The electrode assembly 10 is manufactured by winding the first electrode plate, the second electrode plate, and the separator onto a winding tool. After the winding is completed, the winding tool is withdrawn from the electrode assembly 10. Following the withdrawal of the winding tool, the third feedthrough opening 14 is created in the center of the electrode assembly 10.

[0251] The axial direction of the third through-hole 14 can run parallel to the axial direction of the first through-hole 323. The axis of the third through-hole 14 coincides with the central axis A of the electrode assembly 10. The third through-hole 14 passes through the first terminal 11, the main body 12, and the second terminal 13.

[0252] During electrolyte injection, the electrolyte can flow through the first through-hole 323 and the second through-hole 45 into the third through-hole 14, and the electrolyte flowing into the third through-hole 14 can penetrate the electrode assembly 10 from the inside, thereby improving the penetration efficiency of the electrode assembly 10.

[0253] In some embodiments, the overhang of the third through-hole 14 in the axial direction of the third through-hole 14 falls into the overhang of the second through-hole 45. In this way, the shielding effect of the first connecting tab 11 with respect to the second through-hole 45 can be reduced, allowing the electrolyte to flow unhindered into the third through-hole 14.

[0254] In some embodiments, the first through-hole 323, the second through-hole 45, and the third through-hole 14 are arranged coaxially. The diameter of the third through-hole 14 can be larger than or equal to that of the second through-hole 45.

[0255] In some embodiments, the first through-hole 323 extends from the bottom wall of the groove 324 to the first inner surface 321 and passes through the connecting section 32. During electrolyte injection, the electrolyte injection head presses against the first outer surface 322. This allows the first outer surface 322 to support the injection head and, together with it, ensure a seal, which significantly reduces the risk of electrolyte leakage from the battery cell 7.

[0256] Fig. Figure 12 shows a schematic structure diagram of an electrode assembly and a current collection element of a battery cell according to some other embodiments of this application.

[0257] As illustrated in Fig. 12, there are several third welding sections W3 which are arranged at intervals from each other in the circumferential direction Y of the first connecting lug 11.

[0258] The third welding section W3 can be a straight structure extending radially from the electrode assembly 10, or it can consist of a V-shaped structure, and of course it can also have other structures.

[0259] The multiple third welding sections W3 allow the current flow area to be expanded, the homogeneity of the current density of the first electrode plate to be increased, the intrinsic resistance to be reduced and the current capacity to be improved.

[0260] Fig. Figure 13 shows a partially schematic cross-sectional view of a battery cell according to certain embodiments of this application; Fig. Figure 14 shows an enlarged schematic representation of Block One. Fig. 13.

[0261] As illustrated in Fig. 13 and Fig. 14, in some embodiments the first section 111 is welded to the current collector element 40 to form a second weld area W2.

[0262] The second weld section W2 reduces the contact resistance between the current collector 40 and the first terminal 11, thereby increasing the current capacity. The second weld section W2 is located in close proximity to the connection area 32, thus reducing the conductive path between the connection area 32 and the second weld section W2. This results in a reduction in resistance and an increase in current capacity.

[0263] In some embodiments, the first weld section W1 and the second weld section W2 are integrally joined. The current from the first terminal 11 can be conducted to the electrode terminal 30 through the second weld section W2 and the first weld section W1. This shortens the conductor path, reduces resistance, and increases the current capacity.

[0264] In some embodiments, during the welding process of the connecting section 32 and the current collecting element 40, the current collecting element 40 is first melted through, so that the first welding area W1 and the second welding area W2 are formed simultaneously.

[0265] Fig. Figure 15 shows a schematic exploded view of an electrode terminal of a battery cell as used in some embodiments of the present application; and Fig. Figure 16 shows a schematic top view of an electrode terminal of a battery cell according to some embodiments of this application.

[0266] See Fig. 13 to Fig. 16 together. In some embodiments, the housing 20 comprises a cylinder 21 and a cover 22 connected to the cylinder 21. The cylinder 21 is arranged around the circumference of the electrode assembly 10. The cover 22 is provided with an opening 221 for the electrode guide. The electrode connection 30 is secured in the electrode feedthrough opening 221. The electrode connection 30 comprises a connection body 34. The connection body 34 comprises a column-like section 341, a first retaining element 342, and a second retaining element 343. At least a portion of the column-like section 341 is located in the electrode feedthrough opening 221. The first concave section 31 is arranged in the column-like section 341. The first retaining element 342 and the second retaining element 343 are both connected to and project from the outer side wall of the column-like section 341.The first retaining element 342 and the second retaining element 343 are each arranged on the outside and inside of the cover 22 respectively and are jointly designed to clamp a part of the cover 22.

[0267] The first retaining element 342, which is arranged on the outside of the cover 22, means that the first retaining element 342 is arranged on the side of the cover 22 facing away from the electrode assembly 10; and the second retaining element 343, which is arranged on the inside of the cover 22, means that the second retaining element 343 is arranged on the side of the cover 22 facing the electrode assembly 10.

[0268] In the thickening direction of the cover 22, at least a part of the first retaining element 342 overlaps the cover 22, and at least a part of the second retaining element 343 overlaps the cover 22. The column-shaped section 341 extends through the electrode feedthrough hole 221 to connect the first retaining element 342 and the second retaining element 343, which are each located on two sides of the cover 22.

[0269] The first retaining element 342 and the second retaining element 343 secure the terminal body 34 to the cover 22 by clamping that part of the cover 22 from two sides. The first retaining element 342 and the second retaining element 343 can clamp the cover 22 directly or indirectly through the cover 22 via other components.

[0270] The columnar section 341 can optionally be cylindrical. The first retaining element 342 and the second retaining element 343 both have ring-shaped structures that enclose the columnar section 341.

[0271] In some embodiments, the battery cell 7 further comprises a first insulating element 60 and a second insulating element 70, wherein at least a part of the first insulating element 60 is arranged between the first retaining element 342 and the cover 22, and at least a part of the second insulating element 70 is arranged between the second retaining element 343 and the cover 22. The first insulating element 60 and the second insulating element 70 serve to insulate the terminal body 34 from the cover 22.

[0272] The first insulating element 60 and the second insulating element 70 both have ring-shaped structures that enclose the column-shaped section 341.

[0273] The first insulating element 60 can insulate the first retaining element 342 from the cover 22, and the second insulating element 70 can insulate the second retaining element 343 from the cover 22.

[0274] In some embodiments, either the first insulating element 60 or the second insulating element 70 separates the column-shaped section 341 from the cover 22. For example, part of the first insulating element 60 projects into the electrode feedthrough opening 221 to separate the perforated wall of the electrode feedthrough opening 221 from the column-shaped section 341.

[0275] In some embodiments, the first insulating element 60 and the second insulating element 70 are formed as a single piece. Alternatively, in some other embodiments, the first insulating element 60 and the second insulating element 70 can be provided separately and abut each other.

[0276] In some embodiments, either the first insulating element 60 or the second insulating element 70 is designed to seal the electrode feedthrough opening 221. In some examples, the first retaining element 342 and the cover 22 press against the first insulating element 60, and the first insulating element 60 compresses and seals the electrode feedthrough opening 221 from the outside. In some other examples, the second retaining element 343 and the cover 22 press against the second insulating element 70, and the second insulating element 70 compresses and seals the electrode feedthrough opening 221 from the inside.

[0277] In some embodiments, the battery cell 7 also includes a sealing ring 80, wherein the sealing ring 80 is slid onto the column-shaped section 341 and is designed to seal the electrode feedthrough opening 221. Optionally, part of the sealing ring 80 projects into the electrode feedthrough opening 221 to separate the perforated wall of the electrode feedthrough opening 221 from the column-shaped section 341.

[0278] In some embodiments, the circumference of the first retaining element 342 is provided with a plurality of projecting structures 342a. The plurality of projecting structures 342a are arranged at intervals in the circumferential direction of the column-shaped section 341.

[0279] Optionally, the multitude of protruding structures 342a can be arranged at equal intervals in the circumferential direction of the columnar section 341.

[0280] The first retaining element 342 has a flange shape, which is created by turning the end of the connecting body 34 facing away from the electrode assembly 10 outwards.

[0281] Before the terminal body 34 is installed in the housing 20, the first retaining element 342 of the terminal body 34 is generally a cylindrical structure and is located at the upper end of the column-shaped section 341. The outer side wall of the first retaining element 342 is flush with the outer side wall of the column-shaped section 341. During assembly of the terminal body 34 and the housing 20, the first retaining element 342 is threaded through the electrode feedthrough opening 221 and compressed so that the first retaining element 342 is folded outwards and the terminal body 34 is riveted to the cover 22.

[0282] Before folding the first retaining element 342, its upper end is provided with a plurality of spaced-apart groove structures 342b. After folding, a plurality of protruding structures 342a are formed, spaced at intervals in the circumferential direction of the column-shaped section 341, with the groove structure 342b being formed between the adjacent protruding structures 342a. In this embodiment, the groove structure 342b and the protruding structure 342a serve to simplify the folding of the first retaining element 342 and to reduce the stress concentration on the first retaining element 342.

[0283] In some embodiments, the second retaining element 343 is a retaining structure formed by deforming the end of the terminal body 34 facing the electrode assembly 10 by pressing, such that the end of the terminal body 34 facing the electrode assembly 10 protrudes outwards. During assembly of the cover 22 and the terminal body 34, the external device can compress one end of the terminal body 34 facing the electrode assembly 10. Under the force of this compression, the end of the terminal body 34 facing the electrode assembly 10 extends outwards to form the protruding second retaining element 343.

[0284] In some embodiments, the terminal body 34 has a second outer surface 344, and the first concave section 31 is recessed from the second outer surface 344 towards the electrode assembly 10 to the first outer surface 322 of the connecting section 32.

[0285] The terminal body 34 has a second outer surface 344 and a second inner surface 345, which are arranged opposite each other. The second inner surface 345 faces the electrode assembly 10, and the second outer surface 344 faces away from the electrode assembly 10. The first concave section 31 extends from the second outer surface 344 towards the electrode assembly 10 to the first outer surface 322 of the connecting section 32.

[0286] In some embodiments, the electrode connection 30 also includes a sealing plate 33. The sealing plate 33 is connected to the connection body 34 and seals the opening of the first concave section 31.

[0287] The sealing plate 33 can also be positioned completely outside the first concave section 31, or it could project partially into this first concave section 31. This applies as long as the sealing plate 33 is able to close the opening of the first concave section 31.

[0288] The sealing plate 33 can protect the connection section 32 from the outside, thereby reducing the ingress of external contaminants into the first concave section 31, reducing the risk of damage to the connection section 32 by external contaminants and improving the sealing efficiency of the battery cell 7.

[0289] Furthermore, the sealing plate 33 can also serve to seal the first feedthrough opening 323. After the battery cell 7 has been formed, the sealing plate 33 can reduce the risk of electrolyte leakage through the first feedthrough opening 323 and the first concave section 31, thus improving sealing efficiency.

[0290] In some embodiments, a side wall of the first concave section 31 is provided with a stepped surface 311, at least a part of the sealing plate 33 is housed in the first concave section 31, and the stepped surface 311 is designed to hold the sealing plate 33.

[0291] The first concave section 31 is a stepped concave section, with the outer part being larger than the inner part.

[0292] During assembly of the sealing plate 33, the stepped surface 311 can hold and align the sealing plate 33, thus simplifying the assembly process. At least part of the sealing plate 33 is accommodated in the first concave section 31, thereby reducing the overall dimensions of the electrode connection 30, decreasing the space occupied by the electrode connection 30, and improving the energy density.

[0293] In some embodiments, the sealing plate 33 is welded to the side wall of the first concave section 31 to seal the opening of the first concave section 31.

[0294] In some embodiments, a gap is provided between the sealing plate 33 and the connecting section 32, which serves to avoid the first welding section W1.

[0295] The surface of the first weld section W1 is uneven. When the sealing plate 33 is pressed against the first weld section W1, it vibrates during assembly, impairing the sealing effect. In this embodiment, a gap is provided between the sealing plate 33 and the connecting section 32 to prevent the sealing plate 33 from touching the first weld section W1, to avoid direct contact between the sealing plate 33 and the first weld section W1, to reduce vibration of the sealing plate 33 during the assembly process, and to ensure the sealing effect.

[0296] In some examples, the first concave section 31 has a stepped structure, so that the sealing plate 33 abuts the stepped surface 311 and forms a gap between the sealing plate 33 and the connecting section 32. In some other examples, the connecting section 32 can alternatively be arranged in a stepped structure, so that the sealing plate 33 can abut the connecting section 32 and the groove 324 on the connecting section 32 forms a gap between the sealing plate 33 and the connecting section 32.

[0297] In some embodiments, the sealing plate 33 can be designed to be welded to the battery busbar. Within the battery, the busbar can connect the sealing plate 33 of one battery cell 7 and the cover 22 of another battery cell 7, thus connecting the two battery cells 7 in series.

[0298] In the battery, at least part of the sealing plate 33 protrudes from the second outer surface 344 of the terminal body 34.

[0299] If it is necessary to weld the busbar and the sealing plate 33 together, the busbar is first attached to an upper surface of the sealing plate 33 (i.e., to the outer surface of the sealing plate 33 facing away from the connecting part 32) and then welded to the sealing plate 33.

[0300] The sealing plate 33 protrudes at least partially from the second outer surface 344. This prevents the second outer surface 344 from obstructing the attachment of the sealing plate 33 to the busbar and ensures a secure fit between the busbar and the sealing plate 33.

[0301] In some embodiments, the connecting section 32 is located at the end of the terminal body 34 facing the electrode assembly 10, wherein the first inner surface 321 of the connecting section 32 is flush with the second inner surface 345.

[0302] The second inner surface 345 is a surface of the terminal body 34 facing the electrode assembly 10. The first inner surface 321 of the connecting section 32 forms part of the second inner surface 345. In this way, the terminal body 34 can be attached to the current collector 40 with a flat plate structure. In this embodiment, if the current collector 40 is attached to the second inner surface 345, the connecting section 32 and the current collector 40 can be joined together to facilitate welding the connecting section 32 and the current collector 40.

[0303] Fig. Figure 17 shows a partially schematic cross-sectional view of a battery cell according to certain embodiments of this application.

[0304] As illustrated in Fig. 17, in some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345, which are arranged opposite each other, and the first concave section 31 is recessed from the second outer surface 344 to the first outer surface 322 of the connecting section 32 in the direction facing the electrode assembly 10. The terminal body 34 further comprises a third concave section 35, wherein the third concave section 35 is recessed from the second inner surface 345 to the first inner surface 321 of the connecting section 32 in a direction away from the electrode assembly 10.

[0305] In this embodiment of the application, the first concave section 31 and the third concave section 35 are both arranged such that they reduce the thickness of the connection area 32. This, in turn, can reduce the need for a large depth in the first concave section 31 and simplify the manufacturing process. The arrangement of the third concave section 35 allows the internal volume of the battery cell 7 to be increased and the energy density to be enhanced.

[0306] In some embodiments, the current collector element 40 comprises a terminal connection section 46 and a terminal tab section 47 surrounding the terminal connection section 46, wherein the terminal connection section 46 projects outward in relation to the terminal tab section 47 and extends into the third concave section 35, so that the top of the terminal connection section 46 abuts the first inner surface 321 of the connection section 32.

[0307] The connecting tab section 47 lies between the cover 22 and the first connecting tab 11 and is welded to the second cut 112, thus creating the third weld section W3. Optionally, the connecting tab section 47 can have a ring-shaped, flat plate structure.

[0308] In some embodiments, the current collector 40 is provided with a fourth concave section 48 at a position corresponding to the terminal section 46, wherein the fourth concave section 48 is recessed relative to the surface of the terminal section 47 facing the first terminal 11. The fourth concave section 48 can reduce the space occupied by the terminal section 46 and thus reduce the weight of the current collector 40. For example, the terminal section 46 and the fourth concave section 48 are formed by punching the current collector 40.

[0309] Fig. Figure 18 shows a partially schematic cross-sectional view of a battery cell according to embodiments yet to be determined of this application.

[0310] As illustrated in Fig. 18, in certain embodiments, the connecting body 34 has a second outer surface 344 opposite it and a second inner surface 345. The first concave section 31 is recessed from the second inner surface 345 to the first inner surface 321 of the connecting section 32 in a direction away from the electrode assembly 10.

[0311] In this embodiment, the first concave section 31 is arranged inside the terminal body 34, which ensures the flatness and surface area of ​​the second outer surface 344 and facilitates the connection between the terminal body 34 and an external busbar. Furthermore, arranging the first concave section 31 inside the terminal body 34 allows the interior space of the battery cell 7 to be enlarged and the energy density increased.

[0312] In some embodiments, the current collector element 40 comprises a terminal connection section 46 and a terminal tab section 47 surrounding the terminal connection section 46, wherein the terminal connection section 46 projects outward in relation to the terminal tab section 47 and extends into the first concave section 31, such that the top of the terminal connection section 46 abuts the first inner surface 321 of the connection section 32.

[0313] The connecting tab section 47 lies between the cover 22 and the first connecting tab 11 and is welded to the second cut 112, thus creating the third weld section W3. Optionally, the connecting tab section 47 can have a ring-shaped, flat plate structure.

[0314] In some embodiments, the current collector 40 is provided with a fourth concave section 48 at a position corresponding to the terminal section 46, wherein the fourth concave section 48 is recessed relative to the surface of the terminal section 47 facing the first terminal 11. The fourth concave section 48 can reduce the space occupied by the terminal section 46 and thus reduce the weight of the current collector 40. For example, the terminal section 46 and the fourth concave section 48 are formed by punching the current collector 40.

[0315] Fig. Figure 19 shows a partially schematic cross-sectional view of a battery cell according to certain embodiments of this application.

[0316] As illustrated in Fig. 19, in some embodiments the battery cell 7 can be a prismatic battery cell.

[0317] In some embodiments, the housing 20 includes a cylinder 21 and a cover 22, which are formed as a single unit, with the cylinder 21 arranged around the circumference of the electrode assembly 10. The cylinder 21 can, for example, be a square cylinder.

[0318] The cylinder 21 has an opening at the end opposite the cover 22. The cover plate 50 closes this opening of the cylinder 21 and thus seals it. For example, the cover plate 50 is welded to the cylinder 21.

[0319] In some embodiments, the battery cell further comprises a first electrode terminal 30 and a second electrode terminal 90 having opposite polarities, wherein the first electrode terminal 30 is configured to be electrically connected to a first terminal tab of the electrode assembly 10, and the second electrode terminal 90 is configured to be electrically connected to a second terminal tab of the electrode assembly 10.

[0320] In some embodiments, the first electrode connection 30 and the second electrode connection 90 are mounted in the cover 22.

[0321] In the battery, a busbar connects the electrode terminals of numerous battery cells, allowing them to be connected in series, parallel, or series-parallel. Both the first electrode terminal 30 and the second electrode terminal 90 can be configured to connect to the busbar.

[0322] When the battery is subjected to an external force, the busbar pulls on the cover 22 via the first electrode terminal 30 and the second electrode terminal 90, thereby subjecting the connection between the cover 22 and the cylinder 21 to a force. If the cover 22 and the cylinder 21 are separate structures, for example, if the cover 22 and the cylinder 21 are joined by welding, the connection between the cover 22 and the cylinder 21 may fail under the force. In this embodiment of the application, the cover 22 and the cylinder 21 are formed in one piece. This serves to improve the connection strength between the cover 22 and the cylinder 21 and thus reduce the risk of failure at the connection point.

[0323] In some embodiments, the housing 20 is not electrically connected to either a positive or a negative electrode of the electrode assembly. In other words, this means that the housing 20 is not charged.

[0324] In some embodiments, the first terminal and the second terminal of the electrode assembly 10 are located on the same side of the electrode assembly that faces the cover 22.

[0325] Some embodiments of this application also provide a battery which contains a battery cell according to one of the aforementioned embodiments.

[0326] Some embodiments of this application further provide an electrical device containing the battery cell according to one of the aforementioned embodiments, wherein the battery cell is configured to supply electrical energy. The electrical device may be one of the aforementioned devices or systems that utilize a battery cell.

[0327] See Fig. 4 to Fig. 6. Some embodiments of the present application provide a cylindrical battery cell 7 comprising an electrode assembly 10, a housing 20, an electrode terminal 30, a current collector 40 and a cover plate 50.

[0328] The housing 20 comprises a cylinder 21 and a cover 22, which are formed as a single unit. The cylinder 21 is arranged around the circumference of the electrode assembly 10. The cover 22 is provided with an opening 221 for the electrode guide. The electrode connection 30 is attached in the electrode guide opening 221. The cylinder 21 has an opening at the end opposite the cover 22. The cover plate 50 closes this opening of the cylinder 21 and thus seals the opening of the cylinder 21.

[0329] The electrode assembly 10 comprises a main body 12, a first terminal 11, and a second terminal 13, the first terminal 11 and the second terminal 13 projecting from the main body 12. The first terminal 11 is located at an end of the electrode assembly 10 facing the electrode terminal 30, and the second terminal 13 is located at an end of the electrode assembly 10 facing away from the electrode terminal 30.

[0330] The electrode connection 30 comprises a connection body 34 and a sealing plate 33. The connection body 34 includes a first concave section 31 and a connecting section 32 located on the underside of the first concave section 31. The sealing plate 33 is connected to the connection body 34 and seals the opening of the first concave section 31.

[0331] The current collector element 40 is welded to the first connecting lug 11 and the connecting section 32 in order to electrically connect the first connecting lug 11 and the connecting section 32.

[0332] It should be noted that the embodiments and features of the embodiments in this application can be combined without contradiction.

[0333] Finally, it should be noted that the aforementioned embodiments serve only to describe the technical solutions of this application and are not intended to limit them. Although this application is described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that they may nevertheless make changes to the technical solutions described in the aforementioned embodiments or make equivalent substitutions of some of their technical features without departing from the spirit and scope of the technical solutions of the embodiments of this application. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 2021 / 114156

[0001]

Claims

[1] A battery cell comprising: an electrode assembly comprising a first connecting tab; a housing designed to accommodate the electrode assembly; an electrode connection attached to the housing, wherein the electrode connection comprises a first concave section and a connecting section at the bottom of this first concave section; and a current collector element that is connected to the first connecting lug and welded to the connecting section. [2] The battery cell according to claim 1, wherein the current collector is welded to the connecting section to form a first weld section, wherein in the thickening direction of the connecting section the first weld section extends from a side of the connecting section facing away from the current collector at least to the inside of the current collector. [3] The battery cell according to claim 2, wherein the first weld section in the thickening direction of the connection section does not extend beyond a surface of the current collecting element facing away from the connection section. [4] The battery cell according to claim 2 or 3, wherein the housing comprises a cylinder and a cover connected to the cylinder, the cylinder being arranged on the circumference of the electrode assembly, the cover being provided with an electrode feedthrough opening, and the electrode connection being mounted in the electrode feedthrough opening; wherein the first weld section and the cover are both annular, wherein the outer diameter of the cover is D0, and wherein the inner diameter of the first weld section is D1; ​​and where D1 and D0 satisfy 0.1 ≤ D1 / D0 ≤ 0.

6. [5] The battery cell according to claim 4, wherein the first weld section is an open structure, and wherein a central angle of the first weld section is in the range of 180° to 330°. [6] The battery cell according to claim 4, wherein the first welded section is a closed structure. [7] The battery cell according to any one of claims 4 to 6, wherein 0.2 ≤ D1 / D0 ≤ 0.

4. [8] The battery cell according to any one of claims 4 to 7, wherein D1 is in the range of 5 mm to 14 mm. [9] The battery cell according to any one of claims 4 to 8, wherein the cover and the cylinder are constructed in one piece. [10] The battery cell according to any one of claims 2 to 9, wherein in the thickening direction of the connection section the dimension of the first weld section h and the thickness of a region of the connection section for welding to the current collector element d0 is; and where d0 and h 1 < h / d0 ≤ 1.5 are satisfied. [11] The battery cell according to claim 10, wherein the area thickness of the current collecting element for welding with the connecting section d1, and d0 and d1 ≤ 0.5 ≤ d1 / d0 ≤ 1.

2. [12] The battery cell according to claim 10 or 11, wherein d0 is in the range of 0.4 mm to 1.2 mm. [13] The battery cell according to any one of claims 1 to 12, wherein at least part of the first terminal tab is arranged on a side of the current collector element that is away from the electrode terminal and supports the current collector element. [14] The battery cell according to claim 13, wherein a first section of the first terminal tab is arranged on a side of the connecting section which is turned away from the first concave section and is constructed in such a way as to support a part of the current collecting element which is opposite the connecting section. [15] The battery cell according to claim 14, wherein the first section is welded to the current collecting element to form a second welded section. [16] The battery cell according to any one of claims 13 to 15, wherein a second section of the first connecting tab encloses the perimeter of the first section and is constructed in such a way as to support an area of ​​the current collecting element which is not opposite the connecting section. [17] The battery cell according to claim 16, wherein the second section is welded to the current collecting element to form a third welded section. [18] The battery cell according to claim 17, wherein the current collecting element has a convex section on one side facing the first terminal tab, and wherein the convex section is welded to the second section to form the third welded section. [19] The battery cell according to claim 17 or 18, wherein the first terminal tab is arranged around the central axis of the electrode assembly, and a cross-section of the first terminal tab is annular perpendicular to the central axis; and the outer radius of the first connection lug R is, the minimum distance between the third weld section and the central axis in the radial direction of the first connection lug D2 is, and R and D2 satisfy 0.2 ≤ D2 / R ≤ 0.

8. [20] The battery cell according to claim 19, wherein D2 and R satisfy the condition 0.2 ≤ D2 / D2 ≤ 0.

5. [21] The battery cell according to claim 19 or 20, wherein D2 is in the range of 3.5 mm to 10 mm. [22] The battery cell according to any one of claims 13 to 21, wherein the diameter of the current collecting element is D3, the diameter of the first terminal tab is D4 and D3 is smaller than D4. [23] The battery cell according to claim 22, wherein D3 and D4 satisfy the condition 0.75 ≤ D3 / D4 ≤ 0.97, [24] The battery cell according to claim 22 or 23, wherein D3 is in the range of 35 mm to 44 mm. [25] The battery cell according to one of claims 2 to 5, wherein the connecting section is provided with a groove which is recessed from a first outer surface of the connecting section in a direction towards the electrode assembly, and the first welding section optionally extends from the bottom wall of the groove at least to the inside of the current collecting element. [26] The battery cell according to any one of claims 1 to 25, wherein the housing comprises a cylinder and a cover connected to the cylinder, the cylinder being arranged around the circumference of the electrode assembly, the cover being provided with an electrode feedthrough opening and the electrode connection being mounted in the electrode feedthrough opening; and wherein the electrode connection comprises a connection body, wherein the connection body comprises a column-shaped section, a first retaining element and a second retaining element, wherein at least a part of the column-shaped section is arranged in the electrode feedthrough opening, wherein the first concave section is arranged in the column-shaped section, wherein the first retaining element and the second retaining element are both connected to and project from the outer side wall of the column-shaped section, and wherein the first retaining element and the second retaining element are arranged on the outside and inside of the cover, respectively, and are assembled together to clamp a part of the cover. [27] The battery cell according to claim 26, wherein the terminal body has a second outer surface and the first concave section is set back from the second outer surface in the direction facing the electrode assembly to the first outer surface of the connecting section. [28] The battery cell according to claim 26 or 27, wherein the electrode connection further comprises a sealing plate, wherein the sealing plate is connected to the connection body and wherein an opening of the first concave section seals. [29] The battery cell according to any one of claims 1 to 28, wherein the electrode assembly further comprises a second terminal tab having a polarity opposite to that of the first terminal tab, and wherein the second terminal tab is arranged around the central axis of the electrode assembly; and wherein the first connecting tab is arranged at an end of the electrode assembly facing the electrode terminal, wherein the second connecting tab is arranged at an end of the electrode assembly facing away from the electrode terminal, and wherein the second connecting tab is electrically connected to the housing. [30] The battery cell according to claim 29, wherein the second terminal tab is a negative electrode terminal tab, and wherein a substrate material of the housing is steel. [31] The battery cell according to any one of claims 1 to 30, wherein the housing has an opening at an end away from the electrode connection and the battery cell further comprises a cover plate for closing the opening. [32] A battery comprising the battery cell according to any one of claims 1 to 31. [33] An electrical device comprising the battery according to claim 32, wherein the battery is designed to supply electrical energy.

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