Battery cells and battery packs

Abstract

The present application relates to the field of battery technology and discloses a battery cell and a battery pack. The battery cell comprises: a shell, a battery cell and a cover plate. At least one end of the shell is provided with an opening. The battery cell is provided in the shell. The battery cell comprises a battery cell body and a tab. The tab comprises a first section, a second section, a third section and a fourth section connected in sequence. The first section is connected to the battery cell body. Along the first direction, the second section is located between the first section and the third section. At least a portion of the third section is arranged opposite to the first section along the first direction. Along the first direction, the fourth section is arranged on a side of the third section close to the battery cell body and opposite to at least a portion of the battery cell body. The cover plate blocks the opening, and the tab is electrically connected to the cover plate. The second section has a first connecting portion connected to the first section. Along the second direction, a first spacing distance between the first connecting portion and the first end face of the battery cell body is L, and a thickness of the tab is d, which satisfies the relationship: 0.1 mm 2 ≤L×d≤60mm 2 . It improves the energy density of battery cells.

Description

Technical Field

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

[0002] With the rapid development of science and technology, energy issues have become increasingly prominent. Batteries, as an important energy conversion and storage device, play an indispensable role in many fields such as mobile devices, electric vehicles, and energy storage power stations. Therefore, people have put forward higher requirements on the performance of batteries.

[0003] In related technologies, the battery is mainly composed of a shell, a battery cell and a tab, among which the tab is an important component for electrically connecting the battery cell to the external circuit. It is usually led out from the battery cell and extended into the inside of the battery shell to connect with the electrical connection parts on the shell. However, the tab currently occupies a large space in the shell, resulting in low utilization of the internal space of the shell, thereby reducing the energy density of the battery. Summary of the Invention

[0004] The present application provides a battery cell and a battery pack, which improve the energy density of the battery cell.

[0005] In order to achieve the above objectives, the main technical solutions adopted in this application include:

[0006] In a first aspect, an embodiment of the present application provides a battery cell, which includes: a shell, a battery cell, and a cover plate. Along a first direction, at least one end of the shell is provided with an opening, and the battery cell is provided in the shell. The battery cell includes a battery cell body and a tab. The tab includes a first section, a second section, a third section, and a fourth section connected in sequence. The first section is connected to the battery cell body. Along the first direction, the second section is located between the first section and the third section, and the connection between the second section and the third section is configured as a bent portion so that at least a portion of the third section is arranged opposite to the first section along the first direction. Along the first direction, the fourth section is provided on a side of the third section close to the battery cell body and opposite to at least a portion of the battery cell body. The cover plate is connected to the shell to block the opening, and the tab is further adapted to be electrically connected to the cover plate, wherein the second section has a first connecting portion connected to the first section. Along the second direction, the battery cell body has a first end face and a second end face arranged opposite to each other. Along the second direction, the first connecting portion is closer to the first end face than the second end face. A first spacing distance between the first connecting portion and the first end face is L, and a thickness of the tab is d, satisfying the relationship: 0.1 mm 2 ≤L×d≤60mm 2 , the second direction is perpendicular to the first direction.

[0007] According to the battery cell of the embodiment of the present application, the product of the first spacing distance and the thickness of the tab is controlled to meet 0.1 mm. 2 -60mm 2The range and the eccentric setting of the above-mentioned first connecting portion can make more available space inside the shell while ensuring a certain performance of the tab, thereby reducing the occupation of the tab by the limited space in the shell, which is beneficial to improving the overall energy density of the battery cell.

[0008] In a second aspect, an embodiment of the present application provides a battery pack, comprising the battery cell in the embodiment of the first aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0010] Figure 1 A schematic structural diagram of a battery cell provided in the first embodiment of the present application;

[0011] Figure 2 A schematic structural diagram of a battery cell provided in a second embodiment of the present application;

[0012] Figure 3 A schematic structural diagram of a battery cell provided in the third embodiment of the present application;

[0013] Figure 4 A schematic structural diagram of a battery cell provided in the fourth embodiment of the present application;

[0014] Figure 5 A schematic structural diagram of a battery cell provided in the fifth embodiment of the present application;

[0015] Figure 6 A schematic structural diagram of a battery cell provided in the sixth embodiment of the present application;

[0016] Figure 7 A schematic structural diagram of a battery cell according to the seventh embodiment of the present application;

[0017] Figure 8 A schematic structural diagram of a battery cell according to an eighth embodiment of the present application;

[0018] Figure 9 This is a schematic structural diagram of a battery cell provided in the ninth embodiment of the present application.

[0019] [Description of Reference Numerals]

[0020] Battery cell 100;

[0021] Battery cell 1; battery cell body 11; first end surface 111; second end surface 112; tab 12; first section 121; first sub-section 1211; second sub-section 1212; third side surface 1213; second section 122; first connecting portion 1221; first connecting end 12211; second connecting end 12212; first side surface 1222; second side surface 1223; third section 123; fourth section 124; bent portion 125;

[0022] First insulating member 2; second insulating member 3;

[0023] First direction X; second direction Y. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0026] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0028] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0029] The term "multiple" used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two (including two) groups, and "multiple sheets" refers to more than two (including two) sheets.

[0030] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0031] In some embodiments, the battery may be a battery pack, which includes a battery case and battery cells, wherein the battery cells or battery modules are housed in the battery case.

[0032] In some embodiments, the battery cells may be secondary batteries, which are batteries that can be recharged to activate their active materials after discharge and continue to be used. The battery cells may be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, and the like, although this disclosure is not intended to limit this.

[0033] With the rapid development of science and technology, energy issues have become increasingly prominent. Batteries, as an important energy conversion and storage device, play an indispensable role in many fields such as mobile devices, electric vehicles, and energy storage power stations. Therefore, people have put forward higher requirements on the performance of batteries.

[0034] In related technologies, the battery is mainly composed of a shell, a battery cell and a tab, among which the tab is an important component for electrically connecting the battery cell to the external circuit. It is usually led out from the battery cell and extended into the inside of the battery shell to connect with the electrical connection parts on the shell. However, the tab currently occupies a large space in the shell, resulting in low utilization of the internal space of the shell, thereby reducing the energy density of the battery.

[0035] In view of this, the embodiment of the present application proposes a battery cell 100, which includes: a shell, a battery cell 1 and a cover plate. Along the first direction X, at least one end of the shell is provided with an opening, and the battery cell 1 is arranged in the shell. The battery cell 1 includes a battery cell body 11 and a tab 12. When the tab is bent and converged, the tab 12 includes a first section 121, a second section 122, a third section 123 and a fourth section 124 connected in sequence. The first section 121 is connected to the battery cell body 11. Along the first direction X, the second section 122 is located between the first section 121 and the fourth section 124. The third section 123 and the connection between the second section 122 and the third section 123 are constructed as a bending portion 125, so that at least a portion of the third section 123 is arranged relative to the first section 121 along the first direction X. It can be understood that the relative arrangement does not require that at least a portion of the third section 123 and the first section 121 are parallel to each other. For example, when the tab is bent and converged, at least a portion of the third section 123 and the first section 121 can be parallel or have a certain angle. The specific arrangement is based on assembly requirements and is not specifically limited here. Furthermore, along the first direction X, the fourth section 124 is provided on a side of the third section 123 close to the battery cell body 11 and is arranged opposite to at least a portion of the battery cell body 11. The cover plate is connected to the shell to seal the opening, and the tab 12 is also suitable for being electrically connected to the cover plate, wherein the second section 122 has a first connecting portion 1221 connected to the first section 121. Along the second direction Y, the battery cell body 11 has a first end face 111 and a second end face 112 arranged opposite to each other. Along the second direction Y, the first connecting portion 1221 is closer to the first end face 111 than the second end face 112. The first spacing distance between the first connecting portion 1221 and the first end face 111 is L, and the thickness of the tab 12 is d, satisfying the relationship: 0.1 mm 2 ≤L×d≤60mm 2 , the second direction Y is perpendicular to the first direction X.

[0036] In the above solution, the product of the first spacing distance L and the thickness d of the tab 12 is controlled to meet 0.1 mm. 2 -60mm 2 The range of the first connection portion 1221 and the eccentric setting of the first connection portion 1221 can make more available space inside the shell while ensuring a certain performance of the tab 12, thereby reducing the occupation of the tab 12 on the limited space in the shell, which is beneficial to improving the overall energy density of the battery cell 100.

[0037] The battery disclosed in the embodiments of the present application can be used in, but is not limited to, vehicles, and can also be used in other electrical devices with structural beams, wherein the battery can avoid the structural beams of other electrical devices.

[0038] The battery disclosed in the embodiments of this application can be used, but is not limited to, in an electrical device having longitudinal beams, such as vehicles, ships, or aircraft, and can be used to avoid the battery from the structural beams. The battery disclosed in this application can be used to form a power supply system for such an electrical device.

[0039] The embodiments of the present application provide an electrical device using a battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, a heavy truck, a bus, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0040] For the convenience of description, the following embodiments are described using an electrical device as a vehicle as an example.

[0041] The vehicle can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. The vehicle can be a sedan, an SUV, a heavy-duty truck, or a bus. The vehicle is equipped with a battery, which can be located at the bottom, front, or rear of the vehicle. The battery can be used to power the vehicle, for example, as an operating power source for the vehicle and for its circuit systems, such as those required for starting, navigation, and operation.

[0042] The vehicle may further include a controller and a motor, wherein the controller is used to control the battery to supply power to the motor, for example, for starting, navigation, and operating power requirements of the vehicle during driving.

[0043] In some embodiments of the present application, the battery can serve not only as the operating power source of the vehicle, but also as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0044] The battery cell 100 and the battery pack in this application are described in detail below with reference to the accompanying drawings.

[0045] Please refer to Figures 1-9As shown, in this embodiment, the battery cell 100 includes: a shell, a battery cell 1 and a cover plate. At least one end of the shell is provided with an opening along the first direction X, and the battery cell 1 is arranged in the shell. The battery cell 1 includes a battery cell body 11 and a tab 12. When the tab 12 is bent and converged, the tab 12 includes a first section 121, a second section 122, a third section 123 and a fourth section 124 connected in sequence. The first section 121 is connected to the battery cell body 11. Along the first direction X, the second section 122 is located between the first section 121 and the third section 123, and the connection between the second section 122 and the third section 123 is configured as a bending portion 125, so that at least a portion of the third section 123 is arranged opposite to the first section 121 along the first direction X. It can be understood that when the tab 12 is bent and converged, at least a portion of the third section 123 can be parallel to the first section 121 or have a certain angle with it. The specific setting depends on the assembly requirements and is not specifically limited here. Furthermore, along the first direction X, the fourth section 124 is provided on a side of the third section 123 close to the battery cell body 11 and is arranged opposite to at least a portion of the battery cell body 11. The cover plate is connected to the shell to seal the opening, and the tab 12 is also suitable for being electrically connected to the cover plate, wherein the second section 122 has a first connecting portion 1221 connected to the first section 121. Along the second direction Y, the battery cell body 11 has a first end face 111 and a second end face 112 arranged opposite to each other. Along the second direction Y, the first connecting portion 1221 is closer to the first end face 111 than the second end face 112. The first spacing distance between the first connecting portion 1221 and the first end face 111 is L, and the thickness of the tab 12 is d, satisfying the relationship: 0.1 mm 2 ≤L×d≤60mm 2 , the second direction Y is perpendicular to the first direction X.

[0046] Specifically, the shell is arranged at the outermost side of the battery cell 100. The shell material can be selected from but not limited to aluminum alloy, steel, aluminum-manganese alloy, aluminum-magnesium alloy, stainless steel, nickel-plated steel, etc. At least one end of the shell is provided with an opening to facilitate the installation of the battery cell 1 from the opening into the shell. For example, along the first direction X, an opening is provided at each end of the shell, and the battery cell 1 can be installed into the shell from any one of the openings. The shell is used to protect the battery cell 1 from being invaded by foreign impurities, so as to improve the service life of the battery cell 1.

[0047] The battery cell 1 comprises a positive electrode sheet, a negative electrode sheet, and a separator, with the separator positioned between the two sheets. The positive, negative, and separator sheets are stacked to form the battery cell 1. The positive electrode sheet includes a positive current collector and a positive active material layer, while the negative electrode sheet includes a negative current collector and a negative active material layer. The positive current collector is not particularly limited, as long as it is conductive and does not cause adverse chemical changes in the battery. Materials such as stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver can be used. The negative current collector can be made of copper, stainless steel, nickel, titanium, or the like. In specific embodiments, aluminum can be used for the positive electrode, and copper can be used for the negative electrode. The positive active material layer includes a positive active material, such as a nickel-cobalt-manganese ternary material, lithium iron phosphate, or lithium iron manganese phosphate. The negative active material layer includes a negative active material, such as artificial graphite, natural graphite, or a silicon-based material.

[0048] In the present application, the battery cell 1 includes a battery cell body 11 and tabs 12. The number of tabs 12 is consistent with the number of openings. For example, if an opening is provided at each end of the shell along the first direction X, then two tabs 12 are provided on the battery cell body 11 along the first direction X, wherein one opening corresponds to a positive tab 12, and the other opening corresponds to a negative tab 12. The tab 12 is a key component of the battery, and the internal and external connections of the battery are achieved through the use of the positive and negative tabs 12. The material of the tab 12 can be the same as that of the current collector. For example, the tab 12 can be made of at least one of aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon, nickel or titanium. Furthermore, the tab 12 can be cut from the current collector, or it can be a separately formed metal part. It can be understood that the positive tab 12 is electrically connected to the positive electrode sheet in the battery cell body 11, and the negative tab 12 is electrically connected to the negative electrode sheet in the battery cell body 11.

[0049] The material of the cover plate can be the same as or different from the material of the shell. The cover plate is fixedly connected to the shell and is used to seal the opening. In the present application, the two openings are respectively sealed by a cover plate, and each pole ear 12 is electrically connected to the corresponding cover plate. For example, the pole ear 12 can be directly electrically connected to the cover plate, or it can be electrically connected to the electrode terminal on the cover plate, so that the current inside the battery cell 100 can be efficiently transferred to the outside of the battery, or the external current can be introduced into the battery cell 100, ensuring the smooth flow of electrical energy. This connection is also the basis for the normal operation of the battery cell 100.

[0050] Furthermore, the tab 12 includes a first section 121, a second section 122, a third section 123 and a fourth section 124 connected in sequence, wherein the first section 121 of the tab 12 is fixedly connected to the cell body 11, along the first direction X, that is, along the length direction of the cell body 11, the second section 122 is located between the first section 121 and the third section 123, the second section 122 has a first connection portion 1221 connected to the first section 121, along the second direction Y, the cell body 11 has a first end face 111 and a second end face 112 arranged opposite to each other, along the second direction Y, the first connection portion 1221 is closer to the first end face 111 than the second end face 112, that is, the present application sets the first connection portion 1221 connecting the second section 122 to the first section 121 eccentrically, further, as Figure 2 As shown, the connection between the second section 122 and the third section 123 is configured as a bending portion 125, so that at least a portion of the third section 123 is arranged opposite to the first section 121 along the first direction X. It can be understood that Figure 2 Taking the placement direction of the battery cell 1 shown as an example, the second section 122 extends toward the upper right, and a bend 125 is provided at the connection between the second section 122 and the third section 123, so that the third section 123 extends downward along the second direction Y, so that the first section 121, the second section 122, and the third section 123 are jointly surrounded by a storage space. Since the first connecting portion 1221 is closer to the edge of the battery cell body 11, this is conducive to increasing the space surrounded by the first section 121, the second section 122, and the third section 123. Furthermore, along the first direction X, the fourth section 124 is arranged on the side of the third section 123 close to the battery cell body 11 and is arranged opposite to the battery cell body 11. That is, the fourth section 124 of the tab 12 is arranged in the storage space surrounded by the first section 121, the second section 122, and the third section 123. Such an arrangement can make the layout of the tab 12 in the battery case more compact, which is conducive to reducing the space occupied by the tab 12 in the case.

[0051] It should be noted that after the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, which may cause the tab 12 to be locally thicker or break during the bending process of the tab 12, thereby affecting the performance of the tab 12. In some embodiments of the present application, in order to ensure the performance of the tab 12, the product of the first spacing distance L and the thickness d of the tab 12 should be avoided to be too large or too small, wherein the first spacing distance L is the distance between the first connecting portion 1221 and the first end face 111 in the second direction Y. It can be understood that the first spacing distance L is actually the minimum spacing distance between the first connecting portion 1221 and the first end face 111, and the tab 12 is formed by stacking and converging a plurality of sub-tabs. It can be understood that the battery cell body 11 has a plurality of sub-tabs (the plurality of sub-tabs can be a plurality of positive sub-tabs or a plurality of negative sub-tabs). After the plurality of sub-tabs are stacked and converging to form the tab 12, as shown in FIG. Figure 2 and Figure 9 As shown, due to stacking, bundling, bending and other reasons, the thicknesses of the first section 121, the second section 122, the third section 123 and the fourth section 124 may be different. In the present application, the thickness d of the tab 12 is the number of led-out sub-tabs multiplied by the thickness of a single sub-tab. The thickness d of the tab 12 of the present application shall be based on this.

[0052] For example, when the product of the first spacing distance L and the thickness d of the tab 12 is too large, such as when the thickness d of the tab 12 is too large, a plurality of stacked and converged sub-tabs may produce a large staggered layer, resulting in the tab 12 occupying a large space in the shell, which is not conducive to improving the utilization rate of the internal space of the shell. Alternatively, when the first spacing distance L is too large, the first connecting portion 1221 is farther away from the edge of the battery body 11, thereby reducing the accommodation space formed by the bending of the first section 121, the second section 122, and the third section 123, resulting in insufficient accommodation space and increasing the fourth section 12. 4. There is a risk of overlapping with the first connecting portion 1221; however, the product of the first spacing distance L and the thickness d of the tab 12 cannot be too small. When the product of the first spacing distance L and the thickness d of the tab 12 is too small, for example, the thickness d of the tab 12 is too small, the current carrying capacity of the tab 12 is easily reduced, thereby affecting the conductive performance of the tab 12. Alternatively, when the first spacing distance L is too small, the first connecting portion 1221 is too close to the edge of the battery cell body 11, which may easily cause the tab 12 to deform more when bent, thereby causing the tab 12 to be subjected to greater force, resulting in the risk of the tab 12 breaking.

[0053] In this application, the first spacing distance L and the thickness d of the tab 12 satisfy the relationship: 0.1 mm 2 ≤L×d≤60mm 2 , for example, L×d can be 0.1mm 2 , 0.2mm 2 , 0.5mm 2, 1mm 2 , 2mm 2 , 5mm 2 , 10mm 2 , 20mm 2 , 40mm 2 , 60mm 2 , thus, by controlling the product of the first spacing distance L and the thickness d of the tab 12 to meet 0.1mm 2 -60mm 2 The range of the first connection portion 1221 and the eccentric setting of the first connection portion 1221 can make more available space inside the shell while ensuring a certain performance of the tab 12, thereby reducing the occupation of the tab 12 on the limited space in the shell, which is beneficial to improving the overall energy density of the battery cell 100.

[0054] Please refer to Figure 2 and Figure 3 As shown, in this embodiment, L×d satisfies the relationship: 0.15mm 2 ≤L×d≤25mm 2 , and / or, the first spacing distance L satisfies the relationship: 1.5mm≤L≤30mm, and / or, the thickness d satisfies the relationship: 0.04mm≤d≤3mm.

[0055] Specifically, in order to reduce the space occupied by the tab 12 and improve the space utilization of the shell and the energy density of the battery cell 100 while taking into account the current capacity of the tab 12, the product of the first spacing distance L and the thickness d of the tab 12 can be controlled to meet 0.15mm. 2 -25mm 2 Alternatively, only the first spacing distance L is controlled to meet the range of 1.5mm-30mm, or only the thickness d of the tab 12 is controlled to meet the range of 0.04mm-3mm, or the product of the first spacing distance L and the thickness d of the tab 12 is controlled to meet the range of 0.15mm. 2 -25mm 2 The range of the first spacing distance L and the first spacing distance L meet the range of 1.5mm-30mm, or, at the same time, the product of the first spacing distance L and the thickness d of the tab 12 is controlled to meet 0.15mm 2 -25mm 2 The range of the first spacing distance L and the thickness d of the tab 12 meet the range of 0.04mm-3mm, or, at the same time, the first spacing distance L is controlled to meet the range of 1.5mm-30mm and the thickness d of the tab 12 meets the range of 0.04mm-3mm, or, at the same time, the product of the first spacing distance L and the thickness d of the tab 12 meets 0.15mm 2 -25mm 2The first spacing distance L satisfies the range of 1.5 mm to 30 mm, and the thickness d of the tab 12 satisfies the range of 0.04 mm to 3 mm.

[0056] It should be noted that when the first spacing distance L is too large, the first connecting portion 1221 is farther away from the edge of the battery cell body 11, thereby reducing the accommodation space formed by the bending of the first section 121, the second section 122, and the third section 123, resulting in insufficient accommodation space. When the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, greatly increasing the risk of overlapping between the fourth section 124 and the first connecting portion 1221; and when the first spacing distance L is too small, the first connecting portion 1221 is too close to the edge of the battery cell body 11, which can easily cause the tab 12 to deform significantly when bending, thereby causing the tab 12 to be subjected to greater force, resulting in the risk of the tab 12 breaking.

[0057] Therefore, by controlling the first spacing distance L to meet the range of 1.5 mm-30 mm, it can be ensured that the first spacing distance L is set within a reasonable range, reducing the risk of the fourth section overlapping with the first connecting portion and the risk of the tab 12 being broken.

[0058] Similarly, when the thickness d of the tab 12 is too large, multiple stacked and clustered sub-tabs may produce a large layer mismatch, resulting in the tab 12 occupying a large space in the shell, which is not conducive to improving the utilization rate of the internal space of the shell; and when the thickness d of the tab 12 is too small, it is easy to reduce the current carrying capacity of the tab 12, thereby affecting the conductive performance of the tab 12.

[0059] Therefore, by controlling the thickness d of the tab 12 to meet 0.04 mm-3 mm, the thickness of the tab 12 is ensured to be set within a reasonable range, which can improve the utilization rate of the internal space of the shell and meet the conductivity requirements of the tab 12.

[0060] Optionally, the thickness d of the tab 12 may be 0.04 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0061] Furthermore, L×d is preferably 0.15 mm 2 ≤L×d≤25mm 2 , at this time, L×d can be 0.15mm 2 , 0.2mm 2 , 0.3mm 2 , 0.5mm 2 , 1mm 2 , 2mm 2 , 5mm 2 , 10mm 2 , 15mm 2 , 20mm2 , 25mm 2 .

[0062] The first spacing distance L is preferably 2mm≤L≤15mm. In this case, L×d can be 2mm, 3mm, 5mm, 8mm, 10mm, or 15mm.

[0063] The thickness d of the tab 12 is preferably 0.06 mm ≤ L ≤ 2 mm. In this case, L×d can be 0.06 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, or 2 mm.

[0064] As a specific example, the test results in Table 1 below are test results of multiple specific embodiments and comparative examples.

[0065] Table 1. Test results

[0066]

[0067] The temperature test method of the battery cell 1 includes installing the battery cell 1 into the shell, sealing and welding the cover plate and the shell, and providing a pole on the cover plate, and performing a temperature rise test on the battery. The specific test steps are as follows, wherein:

[0068] 1) For lithium iron phosphate batteries: charge at a constant current rate of 4C to 3.65V, and charge at a constant voltage until the current drops to 0.05C; for ternary batteries: charge at a constant current rate of 4C to 4.25V, and charge at a constant voltage until the current drops to 0.05C; a temperature sensor is connected to the pole. During the charging process, the pole temperature is sampled to obtain the maximum temperature T of the pole area. When the maximum temperature T of the pole area is ≤45℃, it is good; when 45℃<T≤65℃, it is qualified; when T>65℃, it is unqualified.

[0069] Among them, the test of whether the fourth section 124 and the first connecting portion 1221 overlap is carried out by CT imaging, and then their thickness is measured. Whether the bending portions of the second section 122 and the third section 123 are broken is observed after the tab 12 is bent and converged into the shell.

[0070] It can be seen from this that the parameters of Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, and Example 8 are all within the protection range of L, d, and L×d of the above-mentioned present application, the temperature rise test results of the battery cell 100 are all qualified, and the bending portion 125 of the second section 122 and the third section 123 are not broken, and the ratio of the thickness of the overlapping area between the fourth section 124 of the tab 12 and the first connecting portion 1221 / the thickness d of the tab 12 is controlled within 1.4.

[0071] Among them, the first spacing distance L in Examples 1 to 4 is within the preferred protection range of L of this application, the thickness d of the tab 12 in Examples 1 to 4 is within the preferred protection range of d of this application, the formula parameter L×d in Examples 1 to 4 is within the preferred protection range of L×d of this application, the fourth section 124 of the tab 12 in Examples 1 to 4 does not overlap with the first connecting portion 1221, and the tab 12 is fully accommodated in the accommodating space formed by the second section 122 and the third section 123, further reducing the shell space occupied by the tab 12 and improving the space utilization rate of the shell 12; in addition, the bending portion 125 of the second section 122 and the third section 123 is not broken, and the battery has good overcurrent capacity, and the battery cell 100 has good temperature rise performance. When the overcurrent capacity test is performed, the maximum temperature T in the pole area is less than or equal to 45°C.

[0072] The first spacing distance L and the thickness d of the tab 12 in Example 5 are not within the preferred protection range of the corresponding parameters. The formula parameter L×d is within the above-mentioned preferred protection range. It can be seen that the fourth section 124 of the tab 12 does not overlap with the first connecting portion 1221, which improves the space utilization of the shell 12. The bending portion 125 between the second section 122 and the third section 123 is not broken. However, the temperature rise performance of the battery cell 100 is only qualified, mainly because the thickness of the tab 12 is relatively thin.

[0073] The first spacing distance L and the thickness d of the tab 12 in Example 6 are not within the preferred protection range of the corresponding parameters. The formula parameter L×d is within the above-mentioned preferred protection range. It can be seen that the ratio of the thickness of the overlapping area between the fourth section 124 of the tab 12 and the first connecting portion 1221 / the thickness d of the tab 12 is controlled within 1.1, which only has a slight impact on the space occupied by the shell, and the bending portion 125 between the second section 122 and the third section 123 does not break. In addition, the temperature rise performance of the battery cell 100 is good. When the overcurrent capacity test is performed, the maximum temperature T in the pole area is less than or equal to 45°C.

[0074] The first spacing distance L and the thickness d of the tab 12 in Example 7 are within the preferred protection range of the corresponding parameters, and the formula parameter L×d is not within the above-mentioned preferred protection range. The fourth section 124 of the tab 12 in Example 7 overlaps with the first connecting portion 1221. However, the ratio of the thickness of the overlapping area between the fourth section 124 of the tab 12 and the first connecting portion 1221 / the thickness d of the tab 12 is controlled within 1.2, causing the tab 12 to occupy part of the shell space, thereby reducing the space utilization rate. However, the bending portion 125 between the second section 122 and the third section 123 is not broken. At the same time, the temperature rise performance of the battery cell 1 is good.

[0075] The first spacing distance L and the thickness d of the tab 12 in Example 8 are not within the preferred protection range of the corresponding parameters, and the formula parameter L×d is not within the above-mentioned preferred protection range. The fourth section 124 of the tab 12 in Example 8 overlaps with the first connecting portion 1221. The ratio of the thickness of the overlapping area between the fourth section 124 of the tab 12 and the first connecting portion 1221 to the thickness d of the tab 12 is 1.4. The protruding setting of the overlapping area will have a certain impact on the welding of the tab 12 and the cover plate. However, the bending portion 125 between the second section 122 and the third section 123 is not broken. The temperature rise performance of the battery cell 1 is only qualified, and the overcurrent capacity of the tab 12 is average.

[0076] The formula parameter L×d of Comparative Example 1 is lower than the lower limit of the protection range of the corresponding parameter. After the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate. Although the fourth section 124 and the first connecting portion 1221 do not overlap, the bending portion 125 between the second section 122 and the third section 123 is broken, and the temperature rise performance of the battery cell 1 is unqualified, indicating that the current carrying capacity of the tab 12 is very poor, and the maximum temperature T in the pole area is as high as 65°C or above, which does not meet the use requirements.

[0077] The formula parameter L×d of Comparative Example 2 is higher than the upper limit of the protection range of the corresponding parameter. After the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, and the fourth section 124 overlaps with the first connecting portion 1221. The ratio of the thickness of the overlapping area between the fourth section 124 of the tab 12 and the first connecting portion 1221 to the thickness d of the tab 12 is 1.8. The tab 12 overlaps and thickens seriously, and the tab 12 occupies a serious amount of shell space, resulting in a low utilization rate of the shell space. Since the overlapping area is too thick and protrudes, the yield of the subsequent welding of the electrode terminal of the tab 12 and the cover plate deteriorates, which also affects the overcurrent, resulting in a large temperature rise and an unqualified temperature rise.

[0078] It can be seen that the parameter range of the present application reduces the risk of the tabs 12 overlapping and also reduces the risk of the tabs 12 breaking, which is beneficial to improving the reliability of the battery cell 100 .

[0079] Please refer to Figure 4 and Figure 5 As shown, in this embodiment, the first connecting portion 1221 includes a first connecting end 12211 and a second connecting end 12212. Along the second direction Y, the first connecting end 12211 is closer to the first end surface 111 than the second connecting end 12212, and along the second direction Y, the first connecting end 12211 is spaced apart from the free end of the fourth section 124. Figure 5As shown, it should be noted that the free end of the fourth segment is the end away from the connection between the fourth segment and the third segment, and the first spacing distance L satisfies the relationship: 2.5mm≤L≤18mm. It can be understood that the first spacing distance L is the spacing distance between the first connection end 12211 and the first end face 111 along the second direction Y, and the thickness satisfies the relationship: 0.06mm≤d≤2.5mm.

[0080] Specifically, the tab 12 is composed of a plurality of sub-tabs stacked and converged in sequence. It can be understood that the first connecting portion 1221 is stacked with a plurality of sub-tabs, wherein, along the second direction Y, the plurality of stacked sub-tabs include the uppermost sub-tab close to the first end face 111 and the lowermost sub-tab away from the first end face 111, the first connecting portion 1221 at the uppermost sub-tab is formed with a first connecting end 12211, and the first connecting portion 1221 at the lowermost sub-tab is formed with a The second connection end 12212, that is, along the second direction Y, the first connection end 12211 is closer to the first end face 111 than the second connection end 12212. Furthermore, since the connection between the first section 121 and the second section 122 has an angle, the first connection end 12211 is constructed as the first bending root between the first section 121 and the first connection portion 1221, and the second connection end 12212 is constructed as the second bending root between the first section 121 and the first connection portion 1221.

[0081] After the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, and the fourth section 124 may overlap with the first connecting portion 1221 , causing the tab 12 in the area corresponding to the first connecting portion 1221 to be locally thicker, thereby affecting the utilization of the internal space of the shell.

[0082] Based on this, along the second direction Y, the first connection end 12211 is spaced apart from the free end of the fourth section 124. When the tab 12 is squeezed by the cover plate, the free end of the fourth section 124 is at a certain distance from the first connection end 12211 in the second direction Y, thereby reducing the risk of overlap between the fourth section 124 and the first connection portion 1221. At the same time, the first spacing distance L satisfies the relationship: 2.5mm≤L≤18mm, so as to further limit the first spacing distance L, that is, to make the first spacing distance L smaller, which is conducive to making the first connection portion 1221 closer to the edge of the battery cell body 11, thereby forming a larger accommodation space. Similarly, the thickness satisfies the relationship: 0.06mm≤d≤2.5mm, so as to further limit the thickness, that is, to make the thickness smaller, thereby further reducing the risk of overlap between the fourth section 124 and the first connection portion 1221, thereby improving the utilization rate of the internal space of the shell.

[0083] To verify the above conclusion, for example, when the first spacing distance L is 2.5 mm and the thickness d of the tab 12 is 0.06 mm, the product of the first spacing distance L and the thickness d of the tab 12 is 0.15 mm. 2 , that is, the product of the first spacing distance L and the thickness d of the tab 12 satisfies 0.1 mm 2 -60mm 2 Range, after the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, the fourth section 124 and the first connecting portion 1221 do not overlap, and the bending portion 125 between the second section 122 and the third section 123 does not break. At the same time, the temperature rise performance of the battery cell 1 is good, indicating that the tab 12 has a good current carrying capacity.

[0084] Please refer to Figure 5 As shown, in this embodiment, along the second direction Y, the minimum spacing distance between the first connection end 12211 and the free end of the fourth section 124 is h1, which satisfies the relationship: 2mm≤h1≤15mm.

[0085] Specifically, in order to ensure the conductive performance of the pole tab 12 while reducing the risk of overlapping between the fourth segment 124 and the first connecting portion 1221, it is necessary to ensure that the minimum spacing distance between the first connecting end 12211 and the free end of the fourth segment 124 is set within a reasonable range. It can be understood that the pole tab 12 is composed of multiple stacked sub-pole tabs, so the fourth segment may include multiple fourth sub-segments, each of which has a free end, and the minimum spacing distance between the first connecting end 12211 and the free end of the fourth segment 124 is the minimum value of the spacing distance between the first connecting end 12211 and the free ends of the multiple fourth sub-segments.

[0086] When the minimum spacing distance h1 between the first connection end 12211 and the free end of the fourth section 124 is too large, the lead-out length of the tab 12 and thus the battery cell body 11 is shorter, resulting in poor current carrying capacity of the tab 12, affecting the conductive performance of the tab 12. When the minimum spacing distance h1 between the first connection end 12211 and the free end of the fourth section 124 is too small, the risk of the fourth section 124 overlapping with the first connection portion 1221 after the tab 12 is squeezed by the cover plate is increased.

[0087] Therefore, the minimum spacing distance h1 between the first connection end 12211 and the free end of the fourth section 124 satisfies the relationship: 2mm≤h1≤15mm, so that the minimum spacing distance h1 between the first connection end 12211 and the free end of the fourth section 124 is set within a reasonable range, that is, it can meet the conductive performance of the tab 12, and at the same time reduce the risk of overlapping between the fourth section 124 and the first connection part 1221, and avoid the tab 12 in the corresponding area of ​​the first connection part 1221 being locally thicker, thereby affecting the utilization rate of the internal space of the shell.

[0088] Please refer to Figure 4 and Figure 6 As shown, in this embodiment, the first connecting portion 1221 includes a first connecting end 12211 and a second connecting end 12212. Along the second direction Y, the first connecting end 12211 is closer to the first end surface 111 than the second connecting end 12212. Along the second direction Y, the second connecting end 12212 is spaced apart from the free end of the fourth section 124. Figure 6 As shown, it should be noted that the free end of the fourth segment is the end away from the connection between the fourth segment and the third segment, and the first spacing distance L satisfies the relationship: 2.5mm≤L≤15mm. It can be understood that the first spacing distance L is the spacing distance between the first connection end 12211 and the first end face 111 along the second direction Y, and the thickness satisfies the relationship: 0.08mm≤d≤2.5mm.

[0089] Specifically, the tab 12 is composed of a plurality of sub-tabs stacked and converged in sequence. It can be understood that the first connecting portion 1221 is stacked with a plurality of sub-tabs, wherein, along the second direction Y, the plurality of stacked sub-tabs include the uppermost sub-tab close to the first end face 111 and the lowermost sub-tab away from the first end face 111, the first connecting portion 1221 at the uppermost sub-tab is formed with a first connecting end 12211, and the first connecting portion 1221 at the lowermost sub-tab is formed with a The second connection end 12212, that is, along the second direction Y, the first connection end 12211 is closer to the first end face 111 than the second connection end 12212. Furthermore, since the connection between the first section 121 and the second section 122 has an angle, the first connection end 12211 is constructed as the first bending root between the first section 121 and the first connection portion 1221, and the second connection end 12212 is constructed as the second bending root between the first section 121 and the first connection portion 1221.

[0090] After the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, and the fourth section 124 may overlap with the first connecting portion 1221 , causing the tab 12 in the area corresponding to the first connecting portion 1221 to be locally thicker, thereby affecting the utilization of the internal space of the shell.

[0091] Based on this, along the second direction Y, the second connection end 12212 is spaced apart from the free end of the fourth section 124. When the tab 12 is squeezed by the cover plate, the free end of the fourth section 124 is at a certain distance from the second connection end 12212 in the second direction Y, thereby reducing the risk of overlap between the fourth section 124 and the first connection portion 1221. At the same time, the first spacing distance L satisfies the relationship: 2.5mm≤L≤15mm, so as to further limit the first spacing distance L, that is, to make the first spacing distance L smaller, which is conducive to making the first connection portion 1221 closer to the edge of the battery cell body 11, thereby forming a larger accommodation space. Similarly, the thickness of the tab 12 satisfies the relationship: 0.08mm≤d≤2.5mm, so as to further limit the thickness of the tab 12, that is, to make the thickness of the tab 12 smaller, thereby further reducing the risk of overlap between the fourth section 124 and the first connection portion 1221, thereby improving the utilization rate of the internal space of the shell.

[0092] To verify the above conclusion, for example, when the first spacing distance L is 15 mm and the thickness d of the tab 12 is 1.65 mm, the product of the first spacing distance L and the thickness d of the tab 12 is 24.75 mm. 2 , that is, the product of the first spacing distance L and the thickness d of the tab 12 satisfies 0.1 mm 2 -60mm 2 Range, after the battery cell 100 is assembled, the tab 12 will be squeezed by the cover plate, the fourth section 124 and the first connecting portion 1221 do not overlap, and the bending portion 125 between the second section 122 and the third section 123 does not break. At the same time, the temperature rise performance of the battery cell 1 is good, indicating that the tab 12 has a good current carrying capacity.

[0093] Please refer to Figure 6 As shown, in this embodiment, along the second direction Y, the minimum spacing distance between the second connection end 12212 and the free end of the fourth section 124 is h2, satisfying the relationship: 0.5 mm ≤ h2 ≤ 13.5 mm.

[0094] Specifically, in order to ensure the performance of the tab 12 while reducing the risk of overlap between the fourth segment 124 and the first connecting portion 1221, it is necessary to ensure that the minimum spacing distance between the second connecting end 12212 and the free end of the fourth segment 124 is set within a reasonable range. It can be understood that the tab 12 is composed of multiple stacked sub-tabs, so the fourth segment may include multiple fourth sub-segments, each of which has a free end, and the minimum spacing distance between the second connecting end 12212 and the free end of the fourth segment 124 is the minimum value of the spacing distance between the second connecting end 12212 and the free ends of the multiple fourth sub-segments.

[0095] When the minimum spacing distance h2 between the second connection end 12212 and the free end of the fourth section 124 is too large, the lead-out length of the tab 12 and thus the battery cell body 11 is shorter, resulting in poor current carrying capacity of the tab 12, affecting the conductive performance of the tab 12, or causing the first connection portion 1221 to be too close to the edge of the battery cell body 11, resulting in the risk of the tab 12 breaking. When the minimum spacing distance h2 between the second connection end 12212 and the free end of the fourth section 124 is too small, not only is the risk of the fourth section 124 overlapping with the first connection portion 1221 after the tab 12 is squeezed by the cover plate increased, but the risk of the fourth section 124 folding is also increased.

[0096] Therefore, the minimum spacing distance h2 between the first connection end 12211 and the free end of the fourth section 124 satisfies the relationship: 0.5mm≤h2≤13.5mm, so that the minimum spacing distance h2 between the second connection end 12212 and the free end of the fourth section 124 is set within a reasonable range, that is, it can meet the performance of the tab 12 and reduce the risk of breakage of the tab 12, while also reducing the risk of overlapping between the fourth section 124 and the first connection part 1221 and the risk of folding of the fourth section 124.

[0097] In this embodiment, the tab 12 includes multiple layers of stacked sub-tabs, the number of sub-tab layers is greater than or equal to 40, and the first spacing distance L satisfies the relationship: 3 mm ≤ L ≤ 15 mm.

[0098] Specifically, the tab 12 is formed by stacking and converging multiple layers of sub-tabs. When the number of sub-tab layers is greater than or equal to J, the number of sub-tab layers is relatively large, and the risk of stacking errors is relatively large after the multiple layers of sub-tabs are stacked and converging in sequence. Therefore, the first spacing distance L satisfies the relationship: 3mm≤L≤15mm, so as to further limit the first spacing distance L, that is, to make the first spacing distance L smaller, thereby providing a larger accommodation space for the fourth section 124, so as to reduce the risk of overlapping of the staggered tab 12 and the first connecting portion 1221, thereby reducing the space occupied by the tab 12 in the shell, improving the utilization rate of the shell space, and thus improving the energy density of the battery.

[0099] In this embodiment, the pole tab 12 includes multiple layers of stacked sub-pole tabs, each layer of sub-pole tabs has a fourth sub-segment, and multiple fourth sub-segments are stacked to form a fourth segment 124. Along the first direction X, the multiple fourth sub-segments are all arranged on the side of the third segment 123 close to the battery cell body 11 and are all arranged opposite to the battery cell body 11. The first spacing distance L satisfies the relationship: 2mm≤L≤20mm.

[0100] Specifically, the tab 12 is formed by stacking and converging multiple layers of sub-tabs, wherein each layer of sub-tabs has a fourth sub-segment, and multiple fourth sub-segments are stacked to form a fourth segment 124. Along the first direction X, multiple fourth sub-segments are arranged in an accommodating space formed by bending and surrounding the first segment 121, the second segment 122, and the third segment 123. Since the risk of folding after the multiple layers of fourth sub-segments are stacked and converging in sequence is relatively high, the first spacing distance L satisfies the relationship: 2mm≤L≤20mm, thereby providing a larger accommodating space for the fourth segment 124, avoiding the situation where the fourth sub-segment is located outside the accommodating space, and helping to reduce the increase in the risk of folding of the tab 12.

[0101] Please refer to Figure 7 As shown, in this embodiment, along the second direction Y, the bending portion 125 is spaced apart from the first end face 111, and along the second direction Y, the second spacing distance between the bending portion 125 and the first end face 111 is M, and the second spacing distance satisfies the relationship: 0.3mm≤M≤5mm.

[0102] Specifically, the battery cell 100 is Figure 7 Take the placement direction as an example to illustrate, along the second direction Y, the top of the bending portion 125 is spaced apart from the first end face 111, and the second spacing distance between the top of the bending portion 125 and the first end face 111 is M, so that the second spacing distance satisfies the relationship: 0.3mm≤M≤5mm. For example, the second spacing distance can be 0.3mm, 1mm, 2mm, 3mm, 4mm, 5mm. This arrangement prevents the tab 12 from exceeding the width direction of the battery cell body 11, thereby avoiding the space occupied by the tab 12 in the width direction of the battery cell body 11. At the same time, it can ensure that the bending portion 125 and the first end face 111 have a sufficient spacing distance, avoiding the bending portion 125 being too close to the first end face 111, resulting in the risk of short circuit between the bending portion 125 and the shell.

[0103] In this embodiment, the length of the tab 12 is greater than or equal to 20 mm, satisfying the relationship: 0.1 mm 2 ≤L×d≤12mm 2 .

[0104] Specifically, the length of the tab 12 refers to the length of the tab 12 extending from the cell body 11. When measuring, a soft ruler can be used to measure the distance between a portion of the tab 12 close to the cell body 11 and a portion away from the cell body 11 along the extending direction of the tab 12, that is, the length of the tab 12. Alternatively, a line or the like can be used to measure a portion of the tab 12 extending in the extending direction of the tab 12, with one end overlapping the end connected to the cell body 11 and the other end overlapping the portion of the tab 12 away from the cell body 11, and then the length of the line or the like can be measured with a ruler.

[0105] The tab 12 is formed by stacking multiple layers of tabs. It is understandable that the length of each layer of tabs can be the same or different. If the length of the tab 12 is greater than or equal to 20 mm, the first spacing distance L and the thickness d of the tab 12 satisfy the relationship: 0.1 mm 2 ≤L×d≤12mm 2 , so that the product of the first spacing distance L and the thickness d of the tab 12 is smaller. Such an arrangement can provide a larger accommodation space for the fourth section 124. At the same time, it can also prevent the thickness d of the tab 12 from being too thick, which is beneficial to reducing the risk of stacking errors after stacking multiple layers of sub-tabs in the tab 12.

[0106] Please refer to Figure 1 、 Figure 8 and Figure 9 As shown, in this embodiment, the battery cell 100 also includes a first insulating member 2. Along the thickness direction of the second section 122, the second section 122 has a first side surface 1222 close to the first end surface 111 and a second side surface 1223 away from the first end surface 111. The first insulating member 2 is arranged on the first side surface 1222, and at least a portion of the first insulating member covers the bent portion 125.

[0107] Specifically, the first insulating member 2 can be constructed as a first insulating tape. The first insulating member 2 can be selected from but not limited to PET, PP, PE, etc. The first insulating tape can be directly attached to the first side surface 1222 of the second section 122, and the first insulating tape can extend to the bending portion 125 so that at least part of the first insulating tape covers the bending portion 125. In this way, when the tab 12 is bent into the shell, refer to Figure 4 and Figure 8 As shown, the first side surface 1222 of the second segment 122 and the first sub-segment 1211 of the first segment 121 can be prevented from being short-circuited by contact, and the first insulating member 2 covering the bent portion 125 can also avoid contact short-circuiting between the bent portion 125 and the housing.

[0108] Optionally, the first insulating tape can also extend to the outside of the first sub-segment 1211 and the first end face 111 of the battery cell body 11, wherein, along the second direction Y, the first segment 121 is divided into a first sub-segment 1211 and a second sub-segment 1212, and the first sub-segment 1211 is closer to the first end face 111 than the second sub-segment 1212. It should be noted that the outermost surface of the battery cell body 11 is a diaphragm. After the first insulating tape extends to the first end face 111 of the battery cell body 11, it is equivalent to fixing the diaphragm and the tab 12 together in advance, thereby avoiding folding of the diaphragm and reducing the risk of short circuit between the positive and negative poles.

[0109] Please refer to Figure 1 、 Figure 8 and Figure 9As shown, in this embodiment, the battery cell 100 further includes a second insulating member 3 . Along the first direction X, the first section 121 has a third side surface 1213 opposite to the fourth section 124 . The second side surface 1223 and the third side surface 1213 are both provided with a second insulating member 3 .

[0110] Specifically, the second insulating member 3 can be constructed as a second insulating tape, which can be directly adhered to the first side 1222 of the second segment 122 and the third side 1213 of the first segment 121, wherein the third side 1213 of the first segment 121 is the outer side of the second sub-segment 1212. Such a configuration can further prevent the tab 12 from being inserted upside down into the battery cell body 11, thereby helping to further improve the safety performance of the battery cell 100. It can be understood that, along the first direction X, the third segment 123 has a fourth side opposite to the battery cell body 11, and the fourth segment 124 has a fifth side opposite to the third side 1213. The second insulating member 3 can extend the fourth side and the fifth side from the second side 1223 of the second segment 122 to further improve the safety performance of the battery cell 100.

[0111] In this embodiment, along the first direction X, the shell has a first end and a second end that are relatively arranged, and the first end and the second end are both provided with openings. Along the first direction X, the battery cell body 11 has a third end face and a fourth end face that are relatively arranged, wherein the third end face is closer to the first end relative to the fourth end face, and the fourth end face is closer to the second end relative to the third end face, and the third end face and the fourth end face are both provided with a pole ear 12. There are two cover plates, one of the two cover plates is connected to the shell to seal the opening of the first end, and the pole ear 12 of the third end face is suitable for being electrically connected to the cover plate of the first end, the other of the two cover plates is connected to the shell to seal the opening of the second end, and the pole ear 12 of the fourth end face is suitable for being electrically connected to the cover plate of the second end.

[0112] Specifically, along the first direction X, the two ends of the shell are respectively the first end and the second end, the first end of the shell is arranged on the same side as the third end face of the battery cell body 11, and the second end of the shell is arranged on the same side as the fourth end face of the battery cell body 11. There are two cover plates, one of the two cover plates is connected to the shell to block the opening of the first end, and the other of the two cover plates is connected to the shell to block the opening of the second end. The third end face and the fourth end face are both provided with a pole ear 12, and the two pole ears 12 have the same structure, and the pole ear 12 of the third end face is electrically connected to the cover plate of the first end, and the pole ear 12 of the fourth end face is electrically connected to the cover plate of the second end. In this way, when the product of the first spacing distance L and the thickness d of the pole ear 12 is controlled to meet 0.1 mm 2 -60mm 2When the battery is within a certain range, the two tabs 12 can free up more available space inside the shell while meeting certain performance requirements, thereby reducing the occupation of the limited space inside the shell and helping to further improve the overall energy density of the battery cell 100.

[0113] In this embodiment, along the first direction X, the length of the battery cell 100 is N, which satisfies the relationship: 300 mm ≤ N ≤ 600 mm, and L×d satisfies the relationship: 0.2 mm 2 ≤L×d≤24mm 2 .

[0114] Specifically, as the length of the battery cell 100 increases, in order to improve the energy sealing of the battery cell 100, the length of the battery cell body 11 may also increase accordingly. However, the increase in the length of the battery cell body 11 will increase the overcurrent requirement. Based on this, the present application controls the length N of the battery cell 100 within the range of 300mm-600mm. For example, the length N of the battery cell 100 can be 300mm, 350mm, 400mm, 450mm, 500mm, 550, 600mm. By controlling the length N of the battery cell 100 to meet the above range, a balance between energy density and overcurrent requirements is achieved. At the same time, the present application improves the range satisfied by the product of the first spacing distance L and the thickness d of the tab 12, by controlling the product of the first spacing distance L and the thickness d of the tab 12 to meet 0.2mm 2 -24mm 2 range, which can improve the overcurrent while avoiding the occupation of the internal space of the shell by the tab 12 as much as possible, so that the internal space of the shell can be more fully utilized, which can improve the utilization rate of the shell space and the energy density of the battery cell 1.

[0115] Furthermore, in order to enable those skilled in the art to better understand this solution, the preparation method of the battery cell 100 is described in detail below:

[0116] (1) Preparation of positive electrode sheet.

[0117] The prepared positive electrode active material (such as nickel-cobalt-manganese ternary, lithium iron phosphate, lithium manganese iron phosphate), conductive agent acetylene black, and binder PVDF are mixed in a mass ratio of 96:2:2, and solvent NMP is added. The mixture is stirred under the action of a vacuum mixer until the system becomes uniform to obtain a positive electrode slurry; the positive electrode slurry is evenly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying, and then cold pressed and cut to obtain a positive electrode sheet.

[0118] (2) Preparation of negative electrode sheet.

[0119] The negative electrode active material graphite or a mixture of graphite and other active materials (such as silicon-based materials) in different mass ratios, the conductive agent acetylene black, the thickener CMC, and the binder SBR are mixed in a mass ratio of 96.4:1:1.2:1.4, and deionized water is added as a solvent. The mixture is stirred under the action of a vacuum mixer until the system becomes uniform to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying, and then cold pressed and cut to obtain a negative electrode sheet.

[0120] (3) Preparation of electrolyte.

[0121] 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. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0122] (4) Preparation of diaphragm.

[0123] A polyethylene film was selected as the separator.

[0124] (5) Preparation of lithium-ion batteries.

[0125] The above-mentioned positive electrode sheet, diaphragm and negative electrode sheet are stacked in order so that the diaphragm is placed between the positive and negative electrode sheets to play an isolating role. Then the lamination process is used to obtain a bare battery cell. The sub-pole ears are led out from the electrode body of the bare battery cell, and the sub-pole ears are formed by a cutting process; multiple sub-pole ears are gathered to form a pole ear 12, and are pre-welded together by ultrasound, and laser welded to the electrode terminal of the cover plate. After welding, the battery cell 1 is opened into the shell from one end of the shell, and the cover plate and the shell are laser sealed and welded, and the cover plate and the shell at the other end are also sealed and welded; after drying, the electrolyte is injected, and after vacuum packaging, standing, formation, shaping and other processes, a lithium-ion battery is obtained.

[0126] The first spacing distance L is controlled by controlling the folded positions of the plurality of sub-tabs in the cell body 11 , and the thickness of the tab 12 is controlled by the thickness of the selected current collector and the number of sub-tab layers.

[0127] In a second aspect, an embodiment of the present application provides a battery pack, comprising the battery cell 100 in the embodiment of the first aspect of the present application.

[0128] Since the battery pack proposed in the embodiment of the present application is provided with the above-mentioned battery cells 100 , the overall energy density of the battery pack can be improved.

[0129] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0130] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0131] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

[0132] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: A housing, wherein at least one end of the housing is provided with an opening along a first direction; A battery cell is disposed in the shell, the battery cell comprising a battery cell body and a tab, the tab comprising a first segment, a second segment, a third segment, and a fourth segment connected in sequence, the first segment being connected to the battery cell body, the second segment being located between the first segment and the third segment along a first direction, and the connection between the second segment and the third segment being configured as a bent portion, so that at least a portion of the third segment is disposed opposite to the first segment along the first direction, and the fourth segment is disposed on a side of the third segment close to the battery cell body along the first direction and opposite to at least a portion of the battery cell body; a cover plate connected to the housing to block the opening, and the tab is also adapted to be electrically connected to the cover plate; Among them, the second section has a first connecting portion connected to the first section, along the second direction, the battery body has a first end face and a second end face arranged opposite to each other, along the second direction, the first connecting portion is closer to the first end face than the second end face, the first spacing distance between the first connecting portion and the first end face is L, the thickness of the pole ear is d, the pole ear includes multiple layers of stacked sub-pole ears, the thickness of the pole ear is the product of the number of the sub-pole ears and the thickness of a single sub-pole ear, satisfying the relationship: 0.1mm 2 ≤L×d≤60mm 2 , 1.5mm≤L≤30mm, 0.04mm≤d≤3mm, and the second direction is perpendicular to the first direction.

2. The battery cell according to claim 1, wherein: The L×d satisfies the relationship: 0.15mm 2 ≤L×d≤25mm 2 .

3. The battery cell according to claim 1, wherein: The first connecting portion includes a first connecting end and a second connecting end, wherein the first connecting end is closer to the first end surface than the second connecting end along the second direction, and the first connecting end is spaced apart from the free end of the fourth segment along the second direction; The first spacing distance satisfies the relationship: 2.5 mm ≤ L ≤ 18 mm, and the thickness satisfies the relationship: 0.06 mm ≤ d ≤ 2.5 mm.

4. The battery cell according to claim 3, characterized in that Along the second direction, the minimum spacing distance between the first connecting end and the free end of the fourth segment is h1, which satisfies the relationship: 2mm≤h1≤15mm.

5. The battery cell according to claim 1, characterized in that The first connecting portion includes a first connecting end and a second connecting end, wherein along the second direction, the first connecting end is closer to the first end surface than the second connecting end, and along the second direction, the second connecting end is spaced apart from the free end of the fourth segment; The first spacing distance satisfies the relationship: 2.5 mm ≤ L ≤ 15 mm, and the thickness satisfies the relationship: 0.08 mm ≤ d ≤ 2.5 mm.

6. The battery cell according to claim 5, characterized in that Along the second direction, the minimum spacing distance between the second connecting end and the free end of the fourth segment is h2, satisfying the relationship: 0.5 mm ≤ h2 ≤ 13.5 mm.

7. The battery cell according to claim 1, characterized in that The tab includes multiple layers of stacked sub-tabs, the number of sub-tab layers is greater than or equal to 40, and the first spacing distance satisfies the relationship: 3mm≤L≤15mm.

8. The battery cell according to claim 1, wherein: Each layer of the sub-electrode tabs has a fourth sub-segment, and a plurality of the fourth sub-segments are stacked to form the fourth section. Along the first direction, the free ends of the plurality of the fourth sub-segments are all located on a side of the third section close to the battery cell body and are all arranged opposite to at least a portion of the battery cell body. The first spacing distance satisfies the relationship: 2mm≤L≤20mm.

9. The battery cell according to claim 1, characterized in that Along the second direction, the bending portion is spaced apart from the first end surface, and along the second direction, a second spacing distance between the bending portion and the first end surface is M, and the second spacing distance satisfies the relationship: 0.3mm≤M≤5mm.

10. The battery cell according to claim 1, characterized in that The length of the tab is greater than or equal to 20 mm and satisfies the relationship: 0.1 mm 2 ≤L×d≤12mm 2 .

11. The battery cell according to claim 1, characterized in that The battery cell also includes a first insulating member. Along the thickness direction of the second section, the second section has a first side surface close to the first end surface and a second side surface away from the first end surface. The first insulating member is arranged on the first side surface, and at least a portion of the first insulating member covers the bent portion.

12. The battery cell according to claim 11, characterized in that The battery cell further includes a second insulating member. Along the first direction, the first section has a third side surface opposite to the fourth section. The second side surface and the third side surface are both provided with the second insulating member.

13. The battery cell according to claim 1, characterized in that Along the first direction, the housing has a first end and a second end that are opposite to each other, and both the first end and the second end are provided with the opening; Along the first direction, the battery cell body has a third end face and a fourth end face that are oppositely arranged, wherein the third end face is closer to the first end than the fourth end face, and the fourth end face is closer to the second end than the third end face, and the third end face and the fourth end face are both provided with the electrode tab; There are two cover plates, one of which is connected to the shell to block the opening at the first end, and the tab on the third end face is suitable for electrically connecting to the cover plate at the first end, and the other of the two cover plates is connected to the shell to block the opening at the second end, and the tab on the fourth end face is suitable for electrically connecting to the cover plate at the second end.

14. The battery cell according to claim 1, characterized in that Along the first direction, the length of the battery cell is N, which satisfies the relationship: 300 mm ≤ N ≤ 600 mm; The L×d satisfies the relationship: 0.2 mm 2 ≤L×d≤24mm 2 .

15. A battery pack, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 14.

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