Battery cell and battery pack

Abstract

Battery cell, including: a housing body, wherein a first opening is provided at one end of the housing body in a first direction; a first cover plate that closes the first opening; a cell nucleus arranged in the housing body, the cell nucleus comprising a nucleus body and a first connecting tab, the first connecting tab extending from an end section of the nucleus body, the first connecting tab being bent towards the first cover plate and being formed with a first bend point and a second bend point; and a first battery terminal located on the first cover plate, wherein the first battery terminal is welded to the first terminal tab to form a first weld mark area, the first weld mark area being located between the second bend point and an end section of the first terminal tab; wherein a length of the first connecting tab between the first bend point and the second bend point is L, wherein in a second direction a first distance between an edge of the first weld mark area and an edge of the first cover plate is d, wherein in the first direction a second distance between an inside of the first cover plate and a root of the first connecting tab is c, wherein 0.6 mm ≤ L - (d + c) ≤ 20 mm applies, the second direction being perpendicular to the first direction.

Description

Technical field

[0001] The present application relates to the technical field of battery technology, in particular to a battery cell and a battery pack. Technical background

[0002] With the rapid development of science and technology, energy problems are becoming increasingly prominent. As a crucial device for energy conversion and storage, batteries play an indispensable role in many areas such as mobile devices, electric vehicles, and energy storage power plants, which is why higher demands are being placed on the performance of batteries.

[0003] In related technologies, a battery cell consists primarily of a casing, a cell core, a terminal tab, a cover plate, and other components. The terminal tab is a crucial component for the electrical connection of the cell core to an external circuit. Once a battery terminal is electrically connected to the cell core's terminal tab, it serves as the battery's external output terminal. After the terminal tab is welded to a battery terminal on the cover plate, the cover plate and casing must be assembled. However, during the assembly process, the terminal tab must be bent and bundled, which can easily lead to the tab breaking and causing short-circuit interference between the terminal tab and the cover plate or casing, thus impairing the battery cell's performance. Content of the invention

[0004] The present application provides a battery cell and a battery pack that reduce the risk of the terminal tab tearing and of a short circuit in the battery cell.

[0005] To achieve the aforementioned goal, the following technical solutions are mainly used in the present application:

[0006] In a first aspect, embodiments of the present application provide a battery cell comprising a housing body, a first cover plate, a cell core, and a first battery terminal, wherein a first opening is provided at one end of the housing body in a first direction, the first cover plate closing the first opening, the cell core being arranged in the housing body, the cell core comprising a cell core body and a first terminal tab, the first terminal tab extending from an end section of the cell core body, the first terminal tab being bent towards the first cover plate and being formed with a first bend point and a second bend point, the first battery terminal being arranged on the first cover plate, the first battery terminal being welded to the first terminal tab to form a first weld mark area.wherein the first weld mark area lies between the second bend point and an end section of the first connecting tab, wherein a length of the first connecting tab between the first bend point and the second bend point is L, wherein in a second direction a first distance between an edge of the first weld mark area and an edge of the first cover plate is d, wherein in the first direction a second distance between an inside of the first cover plate and a root of the first connecting tab is c, wherein 0.6 mm ≤ L - (d + c) ≤ 20 mm, the second direction being perpendicular to the first direction.

[0007] In the battery cell according to the embodiments of the present application, by controlling the length L of the first terminal tab between the first bending point and the second bending point, the first distance d, and the second distance c such that the relationship 0.6 mm ≤ L - (d + c) ≤ 20 mm is satisfied, it is possible to ensure that the length of the first terminal tab, which is bent and bundled in the housing body, lies within a reasonable range. Such a configuration avoids excessive redundancy in the housing body caused by an excessively long bent and bundled length of the first terminal tab, thereby significantly reducing the risk of interference between the first terminal tab and the housing body during the bending and bundling process. This, in turn, lowers the safety risk of an internal short circuit in the battery cell due to overlapping of the first terminal tab with the housing body.On the other hand, it also prevents the tension from becoming too great during an assembly process of the first cover plate and the housing body due to an excessively short bent and bundled length of the first connecting tab, which helps to reduce the risk of the first connecting tab tearing.

[0008] In a second aspect, embodiments of the present application provide a battery pack comprising a box and the battery cell according to the embodiments of the first aspect, wherein the box comprises a frame and a base plate, wherein the base plate and the frame are rigidly connected and form a receiving space, wherein the battery cell is placed in the receiving space and the base plate is configured to support the battery cell. Images

[0009] To more clearly illustrate the technical solutions in the specific embodiments of the present application or in related technology, the drawings necessary for describing the specific embodiments or related technology are briefly presented below. Obviously, the drawings in the following description represent only some embodiments of the present application. The person skilled in the art can obtain further drawings based on these drawings without inventive step. Fig. Figure 1 is a schematic view of an assembly process of a battery cell according to a first embodiment of the present application; Fig. Figure 2 is a schematic view of an assembly process of a battery cell according to a second embodiment of the present application; Fig.Figure 3 is a schematic view of an assembly process of a battery cell according to a third embodiment of the present application; Fig. Figure 4 is a schematic view of an assembly process of a battery cell according to a fourth embodiment of the present application; Fig. Figure 5 is a schematic structural view of a first cover plate according to an embodiment of the present application; Fig. Figure 6 is a schematic view of a battery cell during a welding assembly according to the first embodiment of the present application; Fig. Figure 7 is a schematic view of a battery cell during a welding assembly according to the second embodiment of the present application. Reference symbol list:

[0010] 100 battery cells; 1-Housing body; 11-First opening; 2-cell nucleus; 21-cell nucleus body; 211-first end face; 212-second end face; 213-third end face; 214-fourth end face; 22-first connecting tab; 221-first section; 222-second section; 223-third section; 224-first bend point; 224a-first virtual bend point; 225-second bending point; 225a-second virtual bending point; 3-First cover plate; 31-First bottom surface; 32-First weld mark area; 321-First end; 322-Second end; 323-First partial weld mark; 324-Second section weld mark; 33-First side surface; 34-Second side surface; 35-First part; 36-Second part; 37-First stage; 4-first bracket; 41-first through hole; X-first direction; Y-second direction; a-fourth distance between the first bending point and the first end surface; d-first distance between the edge of the first weld mark area and the Edge of the first cover plate; j-width of the first stage; k-height of the first stage; t-third distance between the first end face and the second end face. Description of embodiments

[0011] To clarify the objectives, technical solutions, and advantages of the embodiments of this application, the technical solutions in these embodiments, in conjunction with the accompanying drawings, are described clearly and completely below. Obviously, the described embodiments represent only a subset of the embodiments of this application and do not encompass all embodiments. Based on the embodiments in this application, all other embodiments that could be obtained by a person skilled in the art without inventive step fall within the scope of protection of this application.

[0012] The term "and / or" in this application merely represents an associative relationship describing related objects and indicates that three relationships are possible. For example, the expression "A and / or B" can represent three possibilities: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the symbol " / " in this application generally indicates that the related objects before and after it are in an "or" relationship.

[0013] The term "several" as used in this application refers to two or more (including two). Similarly, "several groups" refers to two or more groups (including two groups) and "several sheets" refers to two or more sheets (including two sheets).

[0014] With the rapid development of science and technology, energy problems are becoming increasingly prominent. As a crucial device for energy conversion and storage, batteries play an indispensable role in many areas such as mobile devices, electric vehicles, and energy storage power plants, which is why higher demands are being placed on the performance of batteries.

[0015] In related technologies, a battery cell consists primarily of a casing, a cell core, a terminal tab, a cover plate, and other components. The terminal tab is a crucial component for the electrical connection of the cell core to an external circuit. After the terminal tab is welded to a battery terminal on the cover plate, the cover plate and casing must be assembled. However, during the assembly process, the terminal tab must be bent and bundled, which can easily lead to interference between the terminal tab and the cover plate or casing, thus compromising the assembly efficiency of the battery cell.

[0016] In view of this, the embodiments of the present application propose a battery cell. In the solution described above, by controlling the length L of the first connecting tab between the first bending point and the second bending point, the first distance d and the second distance c such that the relationship 0.6 mm ≤ L - (d + c) ≤ 20 mm is satisfied, it is possible to ensure that the length of the first connecting tab, which is bent and bundled in the housing body, lies within a reasonable range.This configuration avoids excessive redundancy in the housing body caused by an excessively long bent and bundled length of the first terminal tab. This reduces the risk of interference between the first terminal tab and the housing body during the bending and bundling process, thus lowering the safety risk of an internal short circuit in the battery cell due to overlapping of the first terminal tab with the housing body. Furthermore, it prevents excessive stress during the assembly of the first cover plate and the housing body caused by an excessively short bent and bundled length of the first terminal tab, thereby reducing the risk of the first terminal tab breaking.

[0017] For example, the battery cell comprises a cell core which is formed by using positive electrode sheets and negative electrode sheets as carriers for electrochemical materials, by isolating the positive and negative electrode sheets by means of a separator to prevent short circuits, by using electrolyte as an ion transport carrier, by realizing structural protection by means of a housing and by making a connection to external circuits by means of terminals.

[0018] In some embodiments, a positive electrode sheet comprises a positive current collector, wherein the positive current collector has multiple surfaces, with a positive active material being provided on at least one of the surfaces.

[0019] For example, the positive active material is located on a surface of the positive current collector along its thickness direction.

[0020] For example, a metal foil or a composite current collector can be used for the positive current collector. If the positive current collector comprises a metal foil, at least one of the following materials can be used: surface-silver-plated aluminum, surface-silver-plated stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium. If the positive current collector comprises a composite current collector, the composite current collector can include a base layer of polymer material and a metal layer. The composite current collector can be formed by depositing a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) onto a substrate of polymer material (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0021] For example, the positive active material includes, but is not limited to, the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. Other conventional materials suitable as positive active materials for batteries can also be used.

[0022] In some embodiments, the negative electrode sheet comprises a negative current collector and a negative active material. A metal foil or a composite current collector can be used for the negative current collector. If the negative current collector comprises a metal foil, at least one of the following materials can be used: surface-silver-plated aluminum, surface-silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium.

[0023] For example, the negative active material is arranged on a surface of the negative current collector along its thickness direction.

[0024] For example, the negative active material includes, but is not limited to, the following materials: synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate. Other conventional materials known in this field that are suitable as negative active materials for batteries may also be used. The silicon-based material may be at least one material consisting of elemental silicon, a silicon-oxygen compound, a silicon-carbon composite, silicon-nitrogen composites, or a silicon alloy. The tin-based material may be at least one material consisting of elemental tin, a tin-oxygen compound, or a tin alloy. However, the present application is not limited to these materials. These negative active materials may be used individually or in combination with two or more.

[0025] In some embodiments, any known separator with a porous structure that exhibits good chemical and mechanical stability can be chosen as the separator.

[0026] For example, the main materials of the separator include at least one of the following: fiberglass, nonwoven fabric, polyethylene, polypropylene and polyvinylidene fluoride, or ceramic. The separator can be a single-layer film or a multi-layer composite film; there are no particular restrictions. If the separator is a multi-layer composite film, the materials of the individual layers can be the same or different; there are no particular restrictions. The insulating element can be a single component located between the positive and negative electrodes or attached to the surface of the positive and negative electrodes.

[0027] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator form a stacked structure. The stacked structure means that the positive electrode sheet, the negative electrode sheet, and the separator are stacked as individual sheet-like structures. Both the positive electrode sheet and the negative electrode sheet are discontinuous, and there is no continuity between adjacent layers. Furthermore, in the present application, the separator can also be individually sheet-like and discontinuous. In some further embodiments, the separator can also be continuous, while the positive electrode sheet and the negative electrode sheet are discontinuous, thus forming a Z-shaped stacking mechanism.

[0028] In some embodiments, the housing comprises at least one of a steel housing, an aluminum housing, a composite metal housing (such as a copper-aluminum composite housing), etc. Components such as the positive electrode sheet, the negative electrode sheet, and the separator can be encapsulated within the housing.

[0029] In some embodiments, the housing comprises an end cover and a housing body, the housing body being provided with an opening and the end cover closing the opening to form a sealed space for receiving substances such as the electrode assembly and electrolytes. The housing body may be provided with one or more openings. One or more end covers may also be provided. The end cover may also be used to accommodate other battery components, such as a first battery terminal, a pressure relief mechanism, a liquid injection port, etc., which is not limited in the present application. The battery terminal is the current output connection of the battery cell.

[0030] In the following, a battery cell 100 and a battery pack in the present application are described in detail with reference to the attached drawings.

[0031] With reference to Fig. 1 to Fig. In this embodiment, the battery cell 100 comprises a housing body 1, a first cover plate 3, a cell core 2 and a first battery terminal.

[0032] In a first direction X, a first opening 11 is provided at one end of the housing body 1, wherein the first cover plate 3 closes the first opening 11, wherein the cell core 2 is arranged in the housing body 1, wherein the cell core 2 comprises a cell core body 21 and a first connecting tab 22, wherein the first connecting tab 22 extends from an end section of the cell core body 21, wherein the first connecting tab 22 is bent towards the first cover plate 3 and is formed with a first bend point 224 and a second bend point 225, wherein the first battery terminal is arranged on the first cover plate 3, wherein the first battery terminal is welded to the first connecting tab 22 to form a first weld mark area 32, wherein the first weld mark area 32 lies between the second bend point 225 and the end section of the first connecting tab 22.wherein a length of the first connecting tab 22 between the first bend point 224 and the second bend point 225 is L, wherein in a second direction Y a first distance between an edge of the first weld mark area 32 and an edge of the first cover plate 3 is d, wherein in the first direction X a second distance between an inside of the first cover plate 3 and a root of the first connecting tab 22 is c, wherein 0.6 mm ≤ L - (d + c) ≤ 20 mm, wherein the second direction Y is perpendicular to the first direction X.

[0033] Specifically, the housing body 1 is arranged on the outermost side of the battery cell 100, wherein a first opening 11 is provided at one end of the housing body 1 to facilitate the assembly of the cell core 2 through the first opening 11 into the housing body 1, wherein the housing body 1 is used to protect the cell core 2 from the ingress of foreign contaminants in order to increase the lifetime of the cell core 2.

[0034] It should be noted that cell core 2 can be configured as a stacked core or a wound core, which is not specifically restricted here. In the stacked core, the electrode sheets are stacked layer by layer, with the electrode sheets of the same polarity being discontinuous and the separator positioned between a positive and a negative electrode sheet. The wound core is a core with a coiled structure, obtained by stacking and coiling the negative electrode sheet, the separator, and the positive electrode sheet in sequence. The wound core is easy to manufacture and exhibits high production efficiency. Compared to the wound core, the stacked core offers better space utilization within the battery and a relatively lower risk of lithium deposition on the battery's electrode sheets.

[0035] The present application is explained using the example of a cell nucleus 2 formed as a stacked nucleus. As in Fig. As shown in Figure 1, the nucleus 2 comprises a nucleus body 21 and a first connecting tab 22, wherein in the first direction X the nucleus body 21 has a third end face 213 and a fourth end face 214, the third end face 213 being closer to the first opening 11 than the fourth end face 214, and the first connecting tab 22 extending from the third end face 213 of the nucleus body 21. By way of example, the first connecting tab 22 can be configured as a positive connecting tab. In this way, the positive connecting tab is arranged corresponding to the first opening 11 of the housing body 1.

[0036] As a key component of the battery, the first terminal tab 22 plays a primary role in the internal and external connection of the battery. Before the first cover plate 3 is firmly connected to the housing body 1, the first terminal tab 22 must be connected to the first battery terminal of the first cover plate 3; then, the first terminal tab 22 is bent and bundled within the housing body 1 to achieve the firm connection of the first cover plate 3 to the housing body 1.

[0037] Before the first connecting tab 22 is bent and bundled, the battery cell 100 is prepared according to the instructions in Fig. 6 or Fig.The first terminal 22 is positioned in the orientation shown in Figure 7, with the first terminal tab extending in the first direction X and the first cover plate 3 arranged horizontally. At this point, the thickness direction of the first cover plate 3 runs parallel to the second direction Y. The first battery terminal is then welded and fastened to the first terminal tab 22, forming a first weld mark area 32. Welding and fastening methods include, but are not limited to, laser welding, ultrasonic welding. It should be noted that Fig. 6 represents a limit position in which the first connecting tab 22 can be bent and bundled, and that Fig. 7 is any schematic position in which the first connecting tab 22 can be bent normally and bundled.

[0038] If the first connecting tab 22, as in Fig. 1 to Fig.As shown in Figure 4, the first cover plate 3 is firmly connected to the first cover plate 3. Fig. 1 as shown in the orientation. At this point, the thickness direction of the first cover plate 3 runs parallel to the first direction X, with the first weld mark area 32 being located on a first bottom surface 31 of the first cover plate 3, and with the first connecting tab 22 being bent and bundled towards the first cover plate 3 in order to mount the first connecting tab 22 in the housing body 1.

[0039] As in Fig.As shown in Figure 1, the bent and bundled first connecting tab 22 comprises a first section 221, a second section 222, and a third section 223, which are connected sequentially. The first section 221 extends from the third end face 213 of the nucleus body 21. In the first direction X, the second section 222 lies between the first section 221 and the third section 223, and in the first direction X, at least a portion of the third section 223 is arranged opposite the nucleus body 21. That is, the bent and bundled first connecting tab 22 is formed with two bending points: the first bending point 224 between the first section 221 and the second section 222, and the second bending point 225 between the second section 222 and the third section 223.

[0040] To enable the person skilled in the art to better understand the present solution, the formation of the first bend point 224 and the second bend point 225 is described in detail below. The first bend point 224 is located in a bend section between the first section 221 and the second section 222, while the second bend point 225 is located in a bend section between the second section 222 and the third section 223. It should be noted that the first connecting tab 22 is typically formed as several stacked first partial connecting tabs, with the first bend point 224 having several bent first partial connecting tabs arranged in a bend. With reference to Fig. 1 and Fig.In the second direction Y, the first bending point 224 is a bending point formed by a first partial connection tab that is closest to a first side surface 33 of the cover plate, and in the second direction Y, the second bending point 225 is a bending point formed by a first partial connection tab that is closest to the first side surface 33 of the cover plate. To enable the person skilled in the art to better understand the present solution, reference is made to Fig. 1 and Fig. 2 suppose that the first bending point 224 has three stacked first partial connection tabs, wherein in the second direction Y the first bending point 224 is a bending point formed by the lowest first partial connection tab; furthermore, suppose that the second bending point 225 has three stacked first partial connection tabs, wherein the second bending point 225 is a bending point formed by the lowest first partial connection tab.

[0041] Through the interaction of the first bending point 224 and the second bending point 225, at least a part of the bent and bundled third section 223 is arranged opposite the cell core body 21. In this way, the first battery terminal and the third section 223 of the first terminal tab 22 are welded together to form a first weld mark area 32, wherein the first weld mark area 32 lies between the second bending point 225 and the end section of the first terminal tab 22, that is, the first weld mark area 32 lies between the second bending point 225 and the end section of the third section 223.

[0042] It must be ensured that during the bending and bundling process of the first terminal tab 22, the length of which is to be bent and bundled within the housing body 1, remains within a reasonable range. For example, if the length of the first terminal tab 22 is too long, care must be taken during the bending and bundling process to prevent it from interfering with the cover plate or the housing body 1, which could lead to a short circuit and significantly reduce the safety performance of the battery cell. Conversely, if the length of the first terminal tab 22 that can be bent and bundled within the housing body 1 is too short, a situation may arise in which the first cover plate 3 cannot be fitted.At the same time, if the length of the first connecting tab 22 is too short when bent and bundled, it will result in excessive tension on the first connecting tab 22, which can easily cause the first connecting tab 22 to tear.

[0043] Based on this, in the present application, the length L of the first connecting tab 22 between the first bending point 224 and the second bending point 225, the first distance d, and the second distance c are controlled such that they satisfy the relationship 0.6 mm ≤ L - (d + c) ≤ 20 mm, in order to bring the length of the first connecting tab 22, which is bent and bundled in the housing body 1, within a reasonable range. It is understood that all data in the present application are data of a fully assembled battery cell. For example, the length L of the first connecting tab 22 between the first bending point 224 and the second bending point 225, the first distance d, and the second distance c are all data after completion of the battery cell assembly. However, to facilitate the understanding of this solution by those skilled in the art, the present application presents the Fig. 1 to Fig. 4 ready. For example, shows Fig.Figure 1 shows a view of the assembly state in which the first cover plate 3 is not yet firmly connected to the housing body 1. To firmly connect the first cover plate 3 to the housing body 1, it is moved to the right in the first direction X so that it is properly aligned with the first opening 11.

[0044] After the first cover plate 3 has been firmly connected to the housing body 1, the first distance in the second direction Y between the edge of the first weld mark area 32 and the edge of the first cover plate 3 is d, where in the first direction X the second distance between the inside of the first cover plate 3 and the root of the first connecting tab 22 is c. Specifically, after the first cover plate 3 has been firmly connected to the housing body 1, as shown in Fig. 2 and Fig.Figure 3 shows that the first distance d is a distance from a first end 321 to the first side surface 33 in the second direction Y, while the second distance c is a distance from the first bottom surface 31 to the third end surface 213 in the first direction X. It is understood that the first distance d and the second distance c are fixed values.

[0045] As in Fig. 6 and Fig.As shown in Figure 7, before bending and bundling the first connecting tab 22, the first distance d extends in the first direction X, while the second distance c also extends in the second direction Y. A first virtual bending point 224a of the first connecting tab 22 before bending and bundling corresponds to a position of the first bending point 224 of the first connecting tab 22 after bending and bundling. A second virtual bending point 225a of the first connecting tab 22 before bending and bundling corresponds to a position of the second bending point 225 of the first connecting tab 22 after bending and bundling. That is, the length of the first connecting tab 22 between the first bending point 224 and the second bending point 225 is identical to the length of the first connecting tab 22 between the first virtual bending point 224a and the second virtual bending point 225a.To ensure normal bending and bundling of the first connecting tab 22, the length L of the first connecting tab 22 between the first bending point 224 and the second bending point 225, the first distance d, and the second distance c must be controlled such that they satisfy the relationship 0.6 mm ≤ L - (d + c) ≤ 20 mm. For example, L - (d + c) can be 0.6 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 10 mm, 15 mm, or 20 mm.

[0046] This configuration avoids excessive redundancy in the housing body caused by an excessively long bent and bundled length of the first terminal tab. This reduces the risk of interference between the first terminal tab and the housing body during the bending and bundling process, thus lowering the safety risk of an internal short circuit in the battery cell due to overlapping of the first terminal tab with the housing body. Furthermore, it prevents excessive stress during the assembly of the first cover plate and the housing body caused by an excessively short bent and bundled length of the first terminal tab, thereby reducing the risk of the first terminal tab breaking.

[0047] With reference to Fig. 2 and Fig.In this embodiment, 4, the cell nucleus body 21 has a first end surface 211 and a second end surface 212 in the second direction Y, which are arranged opposite each other, wherein a third distance between the first end surface 211 and the second end surface 212 is t, wherein in the second direction Y the second bending point 225 lies between the first bending point 224 and the first end surface 211, wherein a fourth distance between the first bending point 224 and the first end surface 211 is a, where a ≥ t / 2 applies.

[0048] Specifically, the nucleus body 21 has a first end face 211 and a second end face 212 in the second direction Y, which are arranged opposite each other, wherein, if the first cover plate is arranged according to the diagram in Fig. 1 to Fig.In the second direction Y, the first side surface 33 is placed in the orientation shown in Figure 4, and the second side surface 34 is arranged on the same side as the second end surface 212, wherein the third distance between the first end surface 211 and the second end surface 212 is t and the fourth distance between the first bend point 224 and the first end surface 211 is a, wherein by controlling the third distance t and the fourth distance a such that the relationship a ≥ t / 2 holds, the first bend point 224 is brought closer to the second end surface 212 than the first end surface 211, while the second bend point 225 of the first connecting tab 22 lies between the first bend point 224 and the first end surface 211 of the nucleus body 21.

[0049] In this embodiment, the third distance t lies between 4 mm and 40 mm. For example, the third distance t can be 4 mm, 5 mm, 6 mm, 7 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, or 40 mm.

[0050] In this embodiment, the fourth distance a lies between 2.2 mm and 38 mm. For example, the fourth distance a can be 2.2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 38 mm.

[0051] It must be specified that the third distance t and the fourth distance a further satisfy the relationship a ≥ t / 2. For example, with a third distance t of 4 mm, the fourth distance a could be 2.2 mm, 2.5 mm, 3 mm, etc. As another example, with a third distance t of 40 mm, the fourth distance a could be 22 mm, 25 mm, 30 mm, 38 mm, etc.

[0052] This allows for an eccentric arrangement of the first bend point 224 in the second direction Y near the second end face 212, which helps to increase the length of the first connecting tab 22 between the first bend point 224 and the second bend point 225. This allows for better bundling of the first connecting tab 22 and further reduces the risk of excessive redundancy of the first connecting tab 22 in the housing body 1. This, in turn, helps to further reduce the risk of a short circuit due to an overlap of the first connecting tab 22 with the housing body 1. Furthermore, the difficulty of bundling the first connecting tab 22 in the housing body 1 is reduced, thereby increasing assembly efficiency.

[0053] In this embodiment, L - (d + c) ≤ 0.6 mm ≤ L - (d + c) ≤ 18 mm.

[0054] More precisely: If the third distance t and the fourth distance a satisfy the relationship a ≥ t / 2, the first bending point 224 in the second direction Y is eccentrically located near the second end surface 212, which is why the first terminal tab 22 can be bundled better and the part of the first terminal tab 22 in the housing body 1 is less easily redundant; by lowering the upper limit of L - (d + c), for example by setting the maximum value of L - (d + c) to 18 mm, the total length of the first terminal tab 22 can be reduced as much as possible while ensuring the assembly efficiency of the battery cell 100, which helps to reduce the resistance of the first terminal tab 22 and thus increase the current transmission capability of the first terminal tab 22;Furthermore, since the redundancy of the first connection tab 22 in the housing body 1 is reduced, this is also advantageous in reducing the space occupied by the first connection tab 22 in the housing body 1, thereby ensuring better space utilization in the housing body 1.

[0055] With reference to Fig. 2 and Fig. In this embodiment, 4, the cell nucleus body 21 has a first end surface 211 and a second end surface 212 in the second direction Y, which are arranged opposite each other, wherein a third distance between the first end surface 211 and the second end surface 212 is t, wherein in the second direction Y the second bending point 225 lies between the first bending point 224 and the first end surface 211, wherein a fourth distance between the first bending point 224 and the first end surface 211 is a, where a < t / 2 applies.

[0056] Specifically, by controlling the third distance t and the fourth distance a so that they satisfy the relationship a < t / 2, the first bending point 224 is located closer to the first end surface 211 than to the second end surface 212, and the second bending point 225 of the first connecting tab 22 is located between the first bending point 224 and the first end surface 211 of the nucleus body 21.

[0057] In this embodiment, the third distance t lies between 4 mm and 40 mm. For example, the third distance t can be 4 mm, 5 mm, 6 mm, 7 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, or 40 mm.

[0058] In this embodiment, the fourth distance a lies between 0.2 mm and 19 mm. For example, the fourth distance a can be 0.2 mm, 0.5 mm, 1 mm, 2 mm, 5 mm, 7 mm, 10 mm, 15 mm, or 19 mm.

[0059] It must be specified that the third distance t and the fourth distance a further satisfy the relationship a < t / 2. For example, with a third distance t of 4 mm, the fourth distance a could be 0.2 mm, 1 mm, 1.9 mm, etc. As another example, with a third distance t of 40 mm, the fourth distance a could be 2 mm, 10 mm, 19 mm, etc.

[0060] In this way, by eccentrically arranging the first bending point 224 in the second direction Y near the first end face 211, and provided that the length of the first connecting tab 22 bent and bundled in the housing body 1 is within a reasonable range, the length of the first connecting tab 22 between the first bending point 224 and the second bending point 225 can be reduced. This avoids the risk of poor current transmission capability due to an excessively long first connecting tab 22, and also reduces the space occupied by the first connecting tab 22 during bending and bundling in the housing body 1, which is advantageous for increasing the space utilization in the housing body 1.

[0061] With reference to Fig. 1 and Fig.In this embodiment, the battery cell further comprises a first holder 4, wherein the first holder 4 is fixedly arranged in the housing body 1, wherein in the first direction X the first holder 4 lies between the cell core body 21 and the first cover plate 3, wherein the first holder 4 has a first through-hole 41, wherein the first connecting tab 22 is guided through the first through-hole 41 and is connected to the first connecting tab 22.

[0062] Specifically, the first support 4 can be made of insulating materials such as plastic, rubber, etc. In the first direction X, the first support 4 is firmly mounted between the cell core body 21 and the first cover plate 3. To ensure a normal connection of the first connecting tab 22 with the first cover plate 3, the first support 4 is provided with a first through-hole 41 so that the first connecting tab 22 can be guided through the first through-hole 41 and connected to the first cover plate 3. Furthermore, the first support 4 can assume a guiding function for bending the first connecting tab 22 during the bending and bundling process. For example, the first connecting tab 22 is formed with a first bending point 224 at the first through-hole 41.In addition, the first support 4 can also provide insulating support to the first connecting tab 22 to prevent the first connecting tab 22 from overlapping with the cell core body 21 after being bent into the housing body and thus causing a short circuit, thereby significantly increasing the safety of the battery cell 100.

[0063] In this embodiment, the first distance is d, where 1 mm ≤ d ≤ 10 mm.

[0064] Specifically, to ensure the performance of the first terminal 22, it must be ensured that the first distance d is within a reasonable range. If the first distance d is too large, the area of ​​the first weld mark region 32 is affected, which can result in the area of ​​the first weld mark region 32 being too small and thus impairing the current flow between the first terminal 22 and the first battery terminal. If the first distance d is too small, during the bending and bundling process of the first terminal 22, the second bend point 225 of the first terminal 22 must be closer to the first end surface 211, which leads to excessive redundancy of the first terminal 22 in the housing body 1 and is therefore unfavorable for the bending and bundling of the first terminal 22.Based on this, the first distance d is specified in the present application within a range of 1 mm to 10 mm, where, for example, the first distance d can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 7 mm, or 10 mm. This ensures the current-carrying capability of the first terminal 22 while simultaneously avoiding excessive redundancy of the first terminal 22.

[0065] With reference to Fig. 1 to Fig.In this embodiment, the first cover plate 3 comprises in the first direction X a first part 35 and a second part 36 which are connected one after the other, wherein the second part 36 is located on an inside of the first part 35, wherein in the second direction Y a maximum dimension of the first part 35 is larger than a maximum dimension of the second part 36 in order to form a first stage 37, wherein the first stage 37 is configured to be mounted abutting a side wall of the housing body 1.

[0066] Specifically, the first part 35 of the first cover plate 3 has a first side surface 33 and a second side surface 34. It is understood that in the second direction Y, the maximum dimension of the first part 35 corresponds to the distance between the first side surface 33 and the second side surface 34. In the first direction X, the first cover plate 3 further includes the second part 36 connected to the first part 35. The second part 36 is located closer to the cell nucleus 2 than the first part 35. In the second direction Y, the maximum dimension of the first part 35 is larger than the maximum dimension of the second part 36, so that the first part 35 and the second part 36 together form a first stage 37. The first stage 37 is designed to be fitted to the side wall of the housing body 1 to facilitate the positioning and installation of the first cover plate 3 and the housing body 1.For example, the side surface of the first stage 37 is inserted into the first opening 11, with the bottom surface of the first stage 37 being designed to abut the end surface of the housing body 1. This facilitates proper assembly of the first cover plate 3 and the housing body 1, which is advantageous for increasing assembly efficiency.

[0067] With reference to Fig. In this embodiment, 5 is provided that in the first direction X the first step 37 has a width of j, where 0.2 mm ≤ j ≤ 2 mm applies, and in the second direction Y the first step 37 has a height of k, where 0.2 mm ≤ k ≤ 1 mm applies.

[0068] Specifically, as in Fig.As shown in Figure 5, the width j of the first stage 37 can be set within a reasonable range. If the width j of the first stage 37 is set too small, the positioning effect of the first stage 37 is impaired. If the width j of the first stage 37 is set too large, the first stage 37 protrudes too far into the housing body 1, reducing the space available for bending and bundling the first connecting tab 22 and impairing assembly efficiency. Based on this, in the present application, the width j of the first stage 37 is controlled to be within 0.2 mm to 2 mm. For example, the width j of the first stage 37 can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 1 mm, or 2 mm. In this way, the positioning requirements of the first stage 37 are met without taking up too much bundling space for the first connecting tab 22.

[0069] Similarly, the height k of the first stage 37 must also be set within a reasonable range. If the height k of the first stage 37 is set too small, the effect of the flush mounting of the first stage 37 with the housing body 1 is impaired. If the height k of the first stage 37 is set too large, the first stage 37 occupies a relatively large space in the housing body 1 in the second direction Y, thereby indirectly reducing the space for bending and bundling the first connecting tab 22, which impairs assembly efficiency. Based on this, in the present application, the height k of the first stage 37 is controlled to be within 0.2 mm to 1 mm. For example, the height k of the first stage 37 can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or 1 mm.In this way, while simultaneously fulfilling the requirements of the adjacent assembly of the first stage 37, the stress on the bundling space of the first connecting lug 22 is further reduced.

[0070] In this embodiment, the second distance is c, where 2 mm ≤ c ≤ 16 mm.

[0071] Specifically, it is assumed that the first connecting tab 22 and the first battery terminal on the first cover plate 3 are permanently joined by laser welding, as shown in Fig.Figure 6 shows that if the second distance c is too small, the cell core body 21 is easily affected by the heat source of the laser welding, causing shrinkage of the separator within the cell core body 21 due to the heat. This can easily lead to the positive and negative electrode sheets in the cell core body 21 being exposed, which in turn causes a short circuit of the cell core body 21 and seriously impairs the safety performance of the cell core 2. Conversely, if the second distance c is too large, the unused space in the housing body 1 is too great, thus reducing the space utilization inside the battery cell 100. Based on this, in the present application, the second distance c is controlled to be within the range of 2 mm to 16 mm. For example, the second distance c can be 2 mm, 3 mm, 4 mm, 5 mm, 10 mm, or 16 mm. In this way, the safety performance of the cell core 2 is ensured while simultaneously increasing the space utilization.

[0072] In this embodiment, the cell nucleus body 21 is designed as a stacked cell nucleus 2, wherein the stacked cell nucleus 2 comprises several electrode sheets which are stacked successively in the second direction Y, wherein a separator is arranged between each pair of adjacent electrode sheets and on an outer surface of the outermost electrode sheet in the second direction Y, wherein in the second direction Y an area ratio of a projection of the separator onto the first end surface 211 to a projection of the electrode sheet onto the first end surface 211 b is and satisfies 1.02 ≤ b ≤ 1.15, wherein the second distance c is and satisfies 2 mm ≤ c ≤ 15 mm.

[0073] Specifically, the cell nucleus body 21 is configured as a stacked cell nucleus, the stacked cell nucleus comprising a positive electrode sheet, a negative electrode sheet, and a separator. Multiple positive electrode sheets and multiple negative electrode sheets are provided and stacked sequentially in the second direction Y. The term "stacked sequentially" refers to an alternating arrangement in which, in the second direction Y, a positive electrode sheet, a negative electrode sheet, another positive electrode sheet, and another negative electrode sheet are arranged sequentially, with no limit to the number of stacked positive and negative electrode sheets. Stacking multiple positive and negative electrode sheets contributes to increasing the energy density of the battery.

[0074] For example, a stacked nucleus refers to the stacking of several independent, leaf-shaped positive electrode sheets and negative electrode sheets, with each positive electrode sheet and each negative electrode sheet being independent of each other.

[0075] A separator is arranged between adjacent positive and negative electrode sheets, as well as on the outer surface of the outermost positive and negative electrode sheets in the second direction Y. It is understood that the separator, acting as an electronic insulator, effectively prevents the risk of an internal short circuit in the battery during normal operation.

[0076] In this embodiment, in the second direction Y, the area ratio of the separator projection onto the first end face 211 to the electrode sheet projection onto the first end face 211 is b, where 1.02 ≤ b ≤ 1.15. This means that the area of ​​the separator projection onto the first end face 211 is 1.02 to 1.15 times the area of ​​the positive or negative electrode sheet projection onto the first end face 211. This configuration ensures that the separator is larger than the positive or negative electrode sheet, thus reducing the risk of the positive or negative electrode sheet being exposed due to heat shrinkage of the separator. Since the risk of exposure of the positive or negative electrode sheet is reduced, the cell nucleus 21 can be positioned closer to the heat source of the laser welding process. This means that the maximum upper limit of the second distance c can be further reduced.For example, the maximum value of the second distance c is reduced to 15 mm, which helps to fully utilize the space in the housing body 1 and thus indirectly increase the space utilization of the battery cell 100.

[0077] In this embodiment, in the second direction Y, a fifth distance between the end section of the first connecting tab 22 and the second end surface 212 is f, where 0.8 mm ≤ f ≤ 18 mm.

[0078] Specifically, the end section of the first terminal tab 22 is the end section of the third section 223, wherein the end section of the third section 223 is located on a side of the second end 322 of the first weld mark area 32 facing away from the first end 321, and wherein, in the second direction Y, the end section of the third section 223 is closer to the second end face 212 than to the first end face 211. It must be specified that, in the second direction Y, the fifth distance f between the end section of the third section 223 and the second end face 212 must be set within a reasonable range. If the fifth distance f is too small, the first terminal tab 22 will be closer to the housing body 1 after bending and bundling, which can easily lead to the first terminal tab 22 overlapping with the housing body 1 and increasing the risk of a short circuit.If the fifth distance f is too large, the area of ​​the first weld mark region 32 can be affected, potentially resulting in an area of ​​the first weld mark region 32 being too small and thus impairing the current transfer capability between the first terminal 22 and the first battery terminal. Therefore, in the present application, the fifth distance f is set to be within the range of 0.8 mm to 18 mm. For example, the fifth distance f can be 0.8 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 10 mm, 15 mm, or 18 mm. Such a configuration ensures the current transfer capability of the first terminal 22 while simultaneously reducing the risk of a short circuit due to overlapping of the first terminal 22 with the housing body.

[0079] In this embodiment, the end section of the first connecting tab 22 is designed as a bent section. That is, a bent section can be provided at the end section of the third section 223, which further increases the distance of the end section of the first connecting tab 22 from the housing body 1, thus placing the end section of the first connecting tab 22 further away from the housing body 1. This helps to further reduce the risk of a short circuit caused by the first connecting tab 22 overlapping with the housing body 1.

[0080] With reference to Fig. 3 to Fig.In this embodiment, 5 provides that the first weld mark area 32 comprises a first partial weld mark 323 and a second partial weld mark 324, wherein the first partial weld mark 323 is an ultrasonic weld mark and the second partial weld mark 324 is a laser weld mark, wherein in the second direction Y a dimension of the second partial weld mark 324 is smaller than a dimension of the first partial weld mark 323.

[0081] Specifically, in the case of a fixed connection of the first connecting tab 22 with the first battery terminal, several first partial connecting tabs are first welded together in the first connecting tab 22 by ultrasonic welding, and then the first connecting tab 22 and the first battery terminal are welded together by laser welding, whereby the ultrasonic welding forms a first partial weld mark 323 (ultrasonic welding mark) on the first connecting tab 22, and the laser welding forms a second partial weld mark 324 (laser welding mark) between the first connecting tab 22 and the first battery terminal, as described in Fig.As shown in Figure 5, in the second direction Y, the dimension of the first partial weld mark 323 corresponds to the dimension of the first weld mark area 32. By welding in stages, tearing of the first connecting tab 22 can be prevented, which is advantageous for increasing the weld quality between the first connecting tab 22 and the first battery terminal.

[0082] In this embodiment, the battery cell further comprises: a second cover plate, wherein in the first direction X at another end of the housing body 1 a second opening is further provided, wherein the second cover plate closes the second opening, wherein the cell nucleus 2 further comprises a second connecting tab, wherein in the first direction X the second connecting tab and the first connecting tab 22 are arranged opposite each other and the second connecting tab extends from another end section of the cell nucleus body 21, wherein the second connecting tab is bent towards the second cover plate and is formed with a third bending point and a fourth bending point; and a second battery terminal located on the second cover plate, wherein the second battery terminal is welded to the second terminal tab to form a second weld mark area, the second weld mark area being located between the fourth bend point and an end section of the second terminal tab, wherein a length of the first connecting tab 22 between the first bend point 224 and the second bend point 225 is X, wherein in the second direction Y a sixth distance between the edge of the first weld mark area 32 and the edge of the first cover plate 3 is m, wherein in the first direction X a seventh distance between the inside of the first cover plate 3 and the root of the first connecting tab 22 is n, where 0.6 mm ≤ X - (m + n) ≤ 20 mm.

[0083] It should be stated that the second connecting tab and the first connecting tab 22 have similar structural features, that the second cover plate and the first cover plate 3 have similar structural features, and that with regard to the connection method of the second connecting tab with the second battery terminal, specific reference is made to the above description of the first connecting tab 22, the first cover plate 3 and the first connecting tab, which is not repeated here.

[0084] It is understood that by controlling the length L of the second connecting tab between the third and fourth bending points, the sixth distance m, and the seventh distance n such that 0.6 mm ≤ X - (m + n) ≤ 20 mm, the length of the bent and bundled section of the second connecting tab within the housing body 1 can be kept within a reasonable range. This configuration avoids excessive redundancy in the housing body caused by an excessively long bent and bundled section of the second connecting tab, thereby significantly reducing the risk of interference between the second connecting tab and the housing body 1 during the bending and bundling process. Consequently, it also reduces the safety risk of an internal short circuit in battery cell 100 due to overlapping of the second connecting tab with the housing body 1.On the other hand, it also prevents the tension from becoming too great during an assembly process of the second cover plate and the housing body 1 due to an excessively short bent and bundled length of the second connecting tab, which helps to reduce the risk of the second connecting tab tearing.

[0085] In this embodiment, the length L of the first connecting tab 22 between the first bending point 224 and the second bending point 225 satisfies the relationship: 5 mm ≤ L ≤ 40 mm. For example, L can be 5 mm, 6 mm, 7 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm.

[0086] Furthermore, the first distance d satisfies the relationship: 1 mm ≤ d ≤ 20 mm. For example, the first distance d can be 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, 15 mm, 20 mm.

[0087] Furthermore, the second distance c satisfies the relationship: 2 mm ≤ c ≤ 16 mm. For example, the second distance c can be 2 mm, 3 mm, 4 mm, 5 mm, 7 mm, 10 mm, 13 mm, 16 mm.

[0088] The following Table 1 is a table of test results, which presents the test results of several specific embodiments and several comparative examples. Table 1: Table of experimental results L (mm) d (mm) c (mm) L - (d + c) (mm) Does the first connection tab overlap with the housing body? Tear strength test of the first connecting tab Example 1 4 0,8 1,8 1,4 No Passed Execution- 4,7 0,9 1,7 2,1 No Passed example 2 Example 3 5 2 2,4 0,6 No Passed Example 4 7 1 4 2 No Passed Example 5 12,5 8,4 3,1 1 No Passed Example 6 23,7 12,7 6 5 No Passed Example 7 30 20 2 8 No Passed Example 8 35,2 5,2 10 20 No Passed Example 9 40 15 16 9 No Passed Example 10 42,3 16,1 17,8 8,4 No Passed Example 11 17,8 14,6 1,7 1,5 No Passed Example 12 32,4 21,2 4,1 7,1 No Passed Comparative example 1 5,3 2,61 2,13 0,56 No Failed Comparative example 2 32,1 6,8 4,1 21,2 Yes Passed Comparative example 3 6,6 4,4 1,8 0,4 No Failed Comparative example 4 42,5 0,8 1,6 40,1 Yes Failed

[0089] To enable the person skilled in the art to better understand the present solution, a manufacturing process for battery cell 100 is first presented. Subsequently, several exemplary embodiments and comparative examples of the manufactured battery cell 100 are selected for testing.

[0090] The manufacturing process for battery cell 100 is as follows: (1) Preparation of a positive electrode sheet.

[0091] A prepared positive active material (such as nickel-cobalt-manganese ternary, lithium iron phosphate, or lithium manganese phosphate), carbon black as a conductor, and PVDF as a binder are mixed in a mass ratio of 96:2:2. NMP is then added as a solvent, and the resulting mixture is stirred under vacuum mixing until homogeneous to obtain a positive electrode slurry. The positive electrode slurry is applied evenly to two surfaces of an aluminum foil of a positive current collector, dried at room temperature, then transferred to an oven for further drying, and subsequently cold-pressed and cut to produce a positive electrode sheet. (2) Production of a negative electrode sheet.

[0092] Graphite as the negative active material, or a mixture of graphite and other active materials (such as silicon-based materials) in varying mass ratios, acetylene carbon black as a conductor, CMC as a thickener, and SBR as a binder are mixed in a mass ratio of 96.4:1:1.2:1.4. Deionized water is added as a solvent, and the resulting mixture is stirred under vacuum until homogeneous to obtain a negative electrode slurry. The negative electrode slurry is applied evenly to two surfaces of a copper foil of a negative current collector, dried at room temperature, then transferred to an oven for further drying, and subsequently cold-pressed and cut to produce a negative electrode sheet. (3) Preparation of an electrolyte.

[0093] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. A fully dried lithium salt, LiPF6, is then dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L. (4) Manufacturing a separator.

[0094] A polyethylene film is selected as the separator. (5) Manufacturing a lithium-ion battery.

[0095] The positive electrode sheet, the separator, and the negative electrode sheet mentioned above are stacked sequentially, with the separator positioned between the positive and negative electrode sheets to provide insulation. A bare cell core is then obtained through a stacking process, with partial connection tabs being produced from the electrode sheet body of the bare cell core. These partial connection tabs are formed by a cutting process. Several partial connection tabs are combined to form the first connection tab 22. The length L of the first connection tab 22 between the first bend point 224 and the second bend point 225, the first spacing d, and the second spacing c are then selected according to Table 1. The first connection tab 22 and the first battery terminal on the first cover plate 3 are welded together.After welding, the cell core 2 is inserted into the housing body through the first opening. The cover plate and the housing body are laser-sealed and welded, dried, and then filled with electrolyte. After processes such as vacuum encapsulation, curing, forming, and shaping, a lithium-ion battery cell is obtained. The other battery specifications and the welding performance of the housing body and cover plate are the same for the individual embodiments and comparative examples. Procedure for testing whether the first connecting tab 22 is torn:

[0096] For each embodiment and each comparative example, 200 battery cells are used. Each battery cell is placed on a vibration table and subjected to a random vibration test in the Z / Y / X directions and sinusoidal vibration at a constant frequency for twelve hours, as well as two hours of sinusoidal vibration at a constant frequency, under operating conditions of random vibration in each of the Z / Y / X directions and sinusoidal vibration at a constant frequency, in accordance with the national standard GB38031-2020.8.2. The battery cell is then removed and disassembled to check for cracks in the terminal tab. If a crack is present, the number of batteries with a cracked terminal tab is recorded. The percentage of batteries with a cracked terminal tab out of 200 batteries is calculated using the formula (number of batteries with a cracked terminal tab / 200) × 100%.If more than 10% of the batteries have a broken terminal tab, the battery cell fails the terminal tab tear test. If less than 10% of the batteries have a broken terminal tab, the battery cell passes the terminal tab tear test.

[0097] Method for testing whether the first connecting tab 22 overlaps with the housing body:

[0098] For each embodiment and each comparative example, one battery cell 100 is used. The battery cell 100 is discharged at a rate of 0.33 C until the battery's state of charge (SOC) is 0%. Then, the battery cell 100 is charged at a rate of 0.33 C until the SOC is 100%. For the battery cell 100 in the various embodiments and comparative examples, all specification parameters except for the three parameters L, d, and c are the same.

[0099] A Fluke 17B+ digital multimeter is used to measure the voltage U between the first battery terminal and the casing 1. For lithium iron phosphate batteries: If 2 V ≤ U ≤ 3 V, the first terminal 22 is found to not overlap with the casing 1, i.e., the test is passed; if U < 2 V or U > 3 V, the first terminal 22 is found to overlap with the casing 1, i.e., the test is failed. Similarly, for ternary lithium batteries: If 2.2 V ≤ U ≤ 3.2 V, the first terminal 22 is found to not overlap with the casing 1, i.e., the test is passed; if U < 2.2 V or U > 3.2 V, the first terminal 22 is found to overlap with the casing 1, i.e., the test is failed.

[0100] It is evident from this that in embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12, the formula L - (d + c) is within the protected area, but some of the parameters L, d, and c are within their respective protected areas, while others are not. The experimental results show that the first connecting tab 22 does not overlap with the housing body 1 and the tensile strength test of the first connecting tab 22 is passed as long as the formula L - (d + c) is within the protected area.

[0101] In comparison example 1 and comparison example 2, the parameters L, d, c are within the protected area, but L - (d + c) is not. The experimental results show that a phenomenon can occur in which the first connecting tab 22 overlaps with the housing body 1 or fails the tensile strength test.

[0102] In comparison examples 3 and 4, some of the parameters L, d, and c are not within the protected area, and L - (d + c) is also not within the protected area. The experimental results show that a phenomenon can occur in which the first connecting tab 22 overlaps with the housing body 1 or fails the tensile strength test.

[0103] In summary, by controlling the length L of the first connecting tab 22 between the first bending point 224 and the second bending point 225, the first distance d, and the second distance c such that 0.6 mm ≤ L - (d + c) ≤ 20 mm, the length of the first connecting tab 22, which is bent and bundled in the housing body 1, can be kept within a reasonable range. This configuration avoids excessive redundancy in the housing body 1 caused by an excessively long bent and bundled length of the first connecting tab 22, thereby significantly reducing the risk of interference between the first connecting tab 22 and the housing body 1 during the bending and bundling process. Consequently, it also reduces the safety risk of an internal short circuit in the battery cell 100 due to overlapping of the first connecting tab 22 with the housing body 1.On the other hand, it also prevents the tension from becoming too great during an assembly process of the first cover plate 3 and the housing body 1 due to an excessively short bent and bundled length of the first connecting tab 22, which helps to reduce the risk of the first connecting tab 22 tearing.

[0104] In a second aspect, embodiments of the present application provide a battery pack comprising a box and the battery cell 100 according to the embodiments of the first aspect, wherein the box comprises a frame and a base plate, wherein the base plate and the frame are rigidly connected to each other and form a receiving space, wherein the battery cell 100 is placed in the receiving space and the base plate is configured to support the battery cell 100.

[0105] In the battery pack proposed by the embodiments of the present application, the bent and bundled length of the terminal tab in the housing body 1 is within a reasonable range due to the arrangement of the aforementioned battery cell 100. This avoids excessive redundancy in the housing body 1 caused by an excessively long bent and bundled length of the terminal tab, thereby reducing the risk of interference between the terminal tab and the housing body 1 during the bending and bundling process and thus lowering the safety risk of an internal short circuit of the battery cell due to overlapping of the terminal tab with the housing body 1.On the other hand, it also prevents the tension from becoming too great during an assembly process of the cover plate and the housing body 1 due to an excessively short bent and bundled length of the connecting tab, which helps to reduce the risk of the connecting tab tearing.

[0106] It should further be stated that the terms "include," "contain," or any other variant thereof should be understood as non-exclusive inclusion, such that a process, method, product, or device with a series of elements may include not only those elements but also other elements not expressly listed, or may include elements inherent to that process, method, product, or device. Without further limitation, an element limited by the expression "includes a..." does not preclude the presence of other identical elements in a process, method, product, or device containing that element.

[0107] The individual embodiments in this description are presented progressively. Similar and identical parts of the individual embodiments can be cross-referenced. What is emphasized in each embodiment are the differences from other embodiments. Since the system embodiment is fundamentally similar to the process embodiment, its description is relatively simple, and its relevant parts can be referenced in the description of the process embodiment.

[0108] The foregoing merely presents exemplary embodiments of the present application, which are not intended to limit the present application. A person skilled in the art may make various modifications and variations to the present application. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of the present application should fall within the scope of protection of the claims of the present application.

[0109] Although the embodiments of the present application have been described in conjunction with the drawings, a person skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application. Such modifications and variations fall within the scope defined by the appended claims.

[0110] The present application relates to the technical field of battery technology and discloses a battery cell and a battery pack. The battery cell comprises a housing body, a first cover plate, a cell core, and a first battery terminal, wherein a first opening is provided in a first direction at one end of the housing body, wherein the cell core is arranged in the housing body, wherein the first terminal tab extends from an end section of the cell core body, wherein the first terminal tab is bent towards the first cover plate and is formed with a first bend point and a second bend point, wherein the first battery terminal is welded to the first terminal tab to form a first weld mark area, wherein the first weld mark area lies between the second bend point and an end section of the first terminal tab.wherein the length of the first connection tab between the first bend point and the second bend point is L, wherein in a second direction perpendicular to the first direction a first distance between an edge of the first weld mark area and an edge of the first cover plate is d, wherein in the first direction a second distance between an inside of the first cover plate and a root of the first connection tab is c, where 0.6 mm ≤ L - (d + c) ≤ 20 mm. This reduces the risk of the connection tab tearing and of a short circuit in the battery cell. 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 non-patent literature

[0000] Standard GB38031-2020.8.2

[0096]

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