Cylindrical battery, battery pack and electric equipment

Abstract

The invention discloses a cylindrical battery, a battery pack and electric equipment, the cylindrical battery comprises a battery shell and a battery cell arranged in the battery shell, the battery shell comprises a peripheral shell part and end face shell parts, at least one end face shell part is an electric connection output end, and the end face shell parts are arranged in the peripheral shell part. The thickness of the area where the end face shell part serving as the electric connection output end is electrically connected with the battery cell is a mm, and the area of the end face shell part is s square mm; the battery cell comprises a positive plate with a positive electrode material, the powder conductivity of the positive electrode material is b Siemens per millimeter, and the value range of b / (a * s) is 7.4 e <-14 >-7.5 e <-4 >. The value range of b / (a * s) is controlled within the range of 7.4 e <-14 >-7.5 e <-4 >, it can be guaranteed that the battery has the capacity of charging and discharging in a short time, and it can also be guaranteed that when the heat production amount is increased due to large-current charging and discharging, the safety risk when the battery is used is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of battery packs, and more specifically, to a cylindrical battery, a battery pack, and an electrical device. Background Art

[0002] In recent years, with the development of new energy vehicles, batteries have been widely used due to their advantages such as high voltage, high energy density, long cycle life, low self-discharge, and zero pollution. As the power source of new energy vehicles, the charging speed, cycle life, and safety of batteries are crucial.

[0003] A battery cell typically consists of two opposing positive and negative electrodes, a separator separating the two, and an electrolyte located between them. During charging, lithium ions are released from the positive electrode material in the positive electrode, migrate through the electrolyte to the negative electrode, and become embedded in the negative electrode active material. During discharge, the lithium ions embedded in the negative electrode active material are released as free lithium ions, entering the electrolyte and moving toward the positive electrode.

[0004] The start-stop power supply can generate a large current in a short period of time when it is started, causing a large temperature rise in the battery and even the risk of decomposing the electrolyte and causing the diaphragm to melt due to heat, exacerbating the safety risks when using the battery.

[0005] Therefore, how to reduce the safety risks when using batteries is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a cylindrical battery to reduce the safety risks when using the battery;

[0007] Another object of the present application is to provide a battery pack and an electrical device having the above cylindrical battery.

[0008] To achieve the above objectives, this application provides the following technical solutions:

[0009] A first aspect of the present application provides a cylindrical battery, comprising a battery housing and a battery cell disposed within the battery housing, wherein the battery housing comprises an outer peripheral housing portion and end surface housing portions located at both ends of the outer peripheral housing portion, wherein at least one end surface housing portion along the axial direction of the cylindrical battery serves as an electrical connection output end, wherein a region of the end surface housing portion serving as the electrical connection output end and electrically connected to the battery cell has a thickness of a millimeter, and an area of ​​the end surface housing portion is s square millimeters;

[0010] The battery cell includes a positive electrode sheet having a positive electrode material. The powder conductivity of the positive electrode material is b Siemens per millimeter, and the value range of b / (a×s) is: 7.4e -14 ~7.5e -4 .

[0011] The cylindrical battery provided in this application controls the value range of b / (a×s) to 7.4e -14 ~7.5e -4 Within this range, the charge and discharge capacity of cylindrical batteries and the safety risks brought about by temperature rise can be balanced, ensuring that the battery has the ability to charge and discharge in a short period of time, and also ensuring that it has better heat dissipation capabilities when high current charging and discharging causes increased heat generation, thereby reducing the safety risks when the battery is used. When cylindrical batteries need to achieve high current charging and discharging in a short period of time to meet application scenarios with high requirements for charging and discharging speed, the powder conductivity of the positive electrode material, the thickness of the area where the end shell is electrically connected to the battery cell, and the area of ​​the end shell can be controlled according to the relationship b / (a×s), so that b / (a×s) is within 7.4e -14 ~7.5e -4 Within this range, the cylindrical battery's ability to charge and discharge at a high rate in a short period of time can be improved while taking into account the battery's safety performance.

[0012] A second aspect of the present application provides a battery pack comprising the cylindrical batteries described in any one of the above items, wherein the number of the cylindrical batteries is 4 to 16.

[0013] The battery pack provided in this application has all the technical effects of the above-mentioned cylindrical batteries, and will not be described in detail in this article.

[0014] A third aspect of the present application provides an electrical device comprising the battery pack described above.

[0015] The electrical equipment provided in this application has all the technical effects of the above-mentioned battery pack, and will not be described in detail in this article. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 An exploded view of a cylindrical battery disclosed in an embodiment of the present application;

[0018] Figure 2 An exploded view of the end face housing portion and the current collecting plate assembly disclosed in an embodiment of the present application;

[0019] Figure 3 An exploded view of the collecting plate assembly disclosed in an embodiment of the present application;

[0020] Figure 4 A partial cross-sectional view of a cylindrical battery disclosed in an embodiment of the present application;

[0021] Figure 5 This is a partial enlarged view of the cylindrical battery at the pole position disclosed in the embodiment of the present application;

[0022] Figure 6 This is a schematic diagram of the structure of the start-stop power supply disclosed in an embodiment of the present application.

[0023] The meanings of the reference numerals in the figures are as follows:

[0024] 10-cylindrical battery;

[0025] 100 - battery housing; 110 - peripheral housing portion; 120 - end housing portion; 121 - pole; 1211 - pole groove; 122 - housing portion insulating member;

[0026] 200-battery core; 201-core hole;

[0027] 300 - current collecting plate assembly; 310 - first current collecting plate; 311 - first through hole; 320 - second current collecting plate; 321 - second through hole; 330 - current collecting plate insulating frame. DETAILED DESCRIPTION

[0028] The embodiment of the present application discloses a cylindrical battery to reduce safety risks when the battery is used;

[0029] The embodiments of the present application also disclose a battery pack and an electrical device having the above cylindrical battery.

[0030] The following describes the embodiments with reference to the accompanying drawings. It should be noted that, for ease of description, only the parts related to the relevant application are shown in the accompanying drawings. The embodiments and features in the embodiments of this application can be combined with each other unless there is a conflict.

[0031] In some application scenarios, the battery needs to be able to generate a large current in a short period of time, while in other application scenarios, the battery needs to be able to charge and discharge quickly. These scenarios will all cause the battery temperature to rise significantly. Take the start-stop power supply as an example. The start-stop power supply is a special power supply used in the start-stop system of automobile engines. It is designed to meet the power requirements of frequent engine starts and vehicle electronic equipment during the start-stop process. Compared with ordinary automobile power supplies, it needs to have a longer charge and discharge cycle life and instantaneous high current output capability. When the vehicle is temporarily stopped, the start-stop power supply automatically shuts down the engine to save fuel and reduce exhaust emissions. When it is necessary to continue driving, the start-stop system responds quickly, quickly providing a strong current to the starter motor through the start-stop power supply, allowing the engine to restart in a short time.

[0032] The applicant has discovered that in order to enable the battery to generate a large current in a short period of time, the powder conductivity of the positive electrode material can be increased. The greater the powder conductivity of the positive electrode material, the faster the lithium ion transmission speed, and the smoother the movement of electrons in the positive electrode material. During the battery charging and discharging process, the insertion and extraction of lithium ions are made more efficient, thereby improving the charging and discharging efficiency and reducing energy loss. It is possible to achieve high current charging and discharging in a short period of time, meeting application scenarios with high discharge speed requirements, such as fast discharge of start-stop power supplies.

[0033] However, the greater the powder conductivity, the greater the current that can be generated in a short period of time, but it will inevitably lead to a greater temperature rise in the battery, and there is even a risk of decomposing the electrolyte and causing the diaphragm to melt due to heat, which increases the safety risk when using the battery.

[0034] Based on this, an embodiment of the present application discloses a cylindrical battery to reduce safety risks during battery use while meeting the demand for generating a large current in a short period of time.

[0035] like Figure 1 As shown, the cylindrical battery disclosed in the embodiment of the present application includes a battery housing 100 and a battery cell 200 disposed in a receiving cavity of the battery housing 100. The battery housing 100 includes an outer peripheral housing portion 110 and end surface housing portions 120 located at both ends of the outer peripheral housing portion 110.

[0036] The battery casing 100 is used to encapsulate the battery cells 200 and other components, including the electrolyte. The battery casing 100 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylinder, or a hexagonal prism (the battery casing 100 of a cylindrical battery is cylindrical). The shape of the battery casing 100 can be determined based on the specific shape and size of the battery cells 200. The battery casing 100 can be made of a variety of materials, including but not limited to copper, iron, aluminum, stainless steel, and aluminum alloys.

[0037] The battery case 100 typically includes a housing body with an opening at one end to facilitate installation of the battery cells 200 within the housing 100. To seal the opening, the battery case 100 also includes a cover plate positioned over the opening. The cover plate is a component that fits over the opening of the housing body to isolate the space containing the battery cells 200 from the external environment. The shape of the cover plate can be adapted to the shape of the housing body to fit the housing. The cover plate can be made of a material with a certain degree of hardness and strength, such as an aluminum alloy.

[0038] The outer casing portion 110 has a cylindrical structure, forming a cavity for accommodating the battery cell 200. An opening is provided at at least one end of the outer casing portion 110, allowing the battery cell 200 to be loaded into the cavity of the outer casing portion 110 through the opening. End casing portions 120 are provided at both ends of the outer casing portion 110. The end casing portion 120 at one end of the outer casing portion 110 is designed as a separate structure from the outer casing portion 110 (the end casing portion 120 designed as a separate structure from the outer casing portion 110 serves as a cover plate). This allows for an opening in the outer casing portion 110 to facilitate assembly of the battery cell 200. After assembly, the end casing portion 120 is secured to the outer casing portion 110 to seal the opening. The cover plate, one of the end casing portions 120, can be secured to the outer casing portion 110 by welding or bonding.

[0039] The end surface housing portion 120 at the other end of the outer peripheral housing portion 110 can be designed as an integral structure with the outer peripheral housing portion 110 , or can be designed as a split structure.

[0040] At least one end surface housing portion 120 of the battery housing 100 serves as an electrical connection output terminal. The electrical connection output terminals of the two cylindrical batteries are electrically connected via a conductive member. The electrical connection output terminals typically include a positive output terminal and a negative output terminal. When two cylindrical batteries are connected in series, the conductive member needs to be electrically connected to the positive output terminal of one cylindrical battery and the negative output terminal of the other cylindrical battery. When two cylindrical batteries are connected in parallel, the conductive member needs to be electrically connected to the electrical connection output terminals of the same polarity of the two cylindrical batteries.

[0041] The battery cell 200 has a battery cell output terminal, which is generally a tab assembly. The tab assembly generally includes a positive tab assembly and a negative tab assembly according to different polarities. The positive tab assembly is electrically connected to the positive output terminal of the electrical connection output terminal, and the negative tab assembly is electrically connected to the negative output terminal of the electrical connection output terminal.

[0042] The tab assembly is a key component of the battery, which is used to transmit the internal current of the battery cell 200 and lead the internal current of the battery cell 200. The material of the tab assembly can be the same as the material of the current collector. For example, the tab assembly can be made 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 assembly can be cut from the current collector or can be a separately formed metal part. It can be understood that the positive tab assembly is electrically connected to the positive electrode sheet in the battery cell 200, and the negative tab assembly is electrically connected to the negative electrode sheet in the battery cell 200.

[0043] The battery cell 200 is the core of the cylindrical battery and consists of a positive electrode, a negative electrode, a separator, and an electrolyte. The separator is a thin, microporous membrane located between the positive and negative electrodes, isolating them and preventing short circuits. The electrolyte conducts lithium ions between the positive and negative electrodes.

[0044] Battery cell 200 is the smallest charge-discharge unit. It consists of a positive electrode sheet, a negative electrode sheet, and a separator interposed between them, wound or stacked to form the cell body. The positive electrode sheet includes a positive current collector and a positive active material. The positive current collector can be made of a metal such as aluminum foil, nickel foil, stainless steel, or a composite foil formed by combining metal and insulating materials. The positive active material includes a main positive active material, a conductive agent, and a binder. The main positive active material includes one or more lithium-containing positive active materials such as lithium iron phosphate, a ternary material containing nickel, cobalt, and manganese, and lithium iron manganese phosphate. Similarly, the negative electrode sheet includes a negative current collector and a negative active material. The negative current collector can be made of a metal such as copper foil, aluminum foil, stainless steel, or a composite foil formed by combining metal and insulating materials. The negative active material includes a main negative active material, a conductive agent, and a binder. The main negative active material includes one or more lithium-containing positive active materials such as artificial graphite, natural graphite, silicon-carbon, silicon-oxygen, and lithium titanate.

[0045] The tab assembly serves as the current output terminal of the battery cell 200 and is connected to the positive or negative electrode sheet in an integral or separate manner. The diaphragm acts as an insulating layer, preventing contact between the positive and negative electrode sheets, which could cause a short circuit within the battery cell. The diaphragm also acts as a semi-permeable layer, preventing the passage of larger molecules while allowing the passage of smaller charged ions.

[0046] The battery casing 100 is the outer protective structure of a cylindrical battery, housing and protecting internal components (such as the battery cells 200). The primary function of the battery casing 100 is to prevent harmful substances such as moisture and oxygen from entering the interior, thereby preventing damage to the battery cells 200. It also protects the battery cells 200 and other components within from external physical impact and chemical corrosion, thereby ensuring the safety and stability of the cylindrical battery.

[0047] The thickness of the end housing portion 120, which serves as the electrical connection output terminal and is electrically connected to the battery cell 200, is a millimeter, and the area of ​​the end housing portion 120 is s square millimeters. The positive electrode sheet of the battery cell 200 includes a positive electrode material, and the powder conductivity of the positive electrode material is b Siemens per millimeter. Therefore, the value range of b / (a×s) is: 7.4e -14 ~7.5e -4 For example, the value of b / (a×s) can be 7.4e -14 、10e -14 、4e -13 、10e -13 、4e-12 、8e -12 、3e -11 、9e -11 、2e -10 , 7.4e -10 、3e -9 、8e -9 、2e -8 、7e -8 、6e -6 、8e -5 , 7.5e -4 This embodiment does not limit the specific value of b / (a×s) and is not limited to the specific values ​​listed above. Those skilled in the art can choose between 7.4e and 7.4e as needed. -14 ~7.5e -4 Select within the range.

[0048] The cylindrical battery disclosed in the embodiment of the present application has b / (a×s) at 7.4e -14 ~7.5e -4 Taking values ​​within a certain range can balance the charge and discharge capabilities of cylindrical batteries and the safety risks brought about by temperature rise, that is, under the premise of ensuring that the cylindrical battery has better charge and discharge efficiency, it can prevent safety risks caused by excessive temperature rise. It can not only ensure that the battery has the ability to charge and discharge in a short period of time, but also ensure that it has better heat dissipation capabilities when the heat generation increases due to high current charging and discharging, so as to reduce the safety risks when the battery is in use. When the cylindrical battery needs to realize high current charging and discharging in a short period of time to meet the application scenarios with high requirements for charging speed, the powder conductivity of the corresponding positive electrode material can be selected according to the needs, that is, b is controlled within a reasonable numerical range so that it can meet the use requirements. It should be noted that the specific value of b must satisfy that the value of b / (a×s) is between 7.4e -14 ~7.5e -4 within the range.

[0049] By controlling the conductivity range of the positive electrode powder, the lithium ion transfer rate can be increased. The faster the lithium ion transfer rate, the smoother the lithium ions can move within the positive electrode active material. During the charge and discharge process of the cylindrical battery, the insertion and extraction of lithium ions are more efficient, thereby improving the charge and discharge efficiency. It can achieve high current charge and discharge in a short period of time, meeting the application scenarios with high discharge speed requirements, such as fast discharge of start-stop power supplies.

[0050] Further controlling a (the thickness of the region where the end surface shell portion 120 is electrically connected to the battery cell 200 ) can shorten the current transmission path and improve the charge and discharge capabilities in a short period of time.

[0051] Further controlling s (the area of ​​the end surface housing portion 120 ) can improve its heat dissipation capability.

[0052] The larger the value of b / (a×s), the thinner the end housing portion 120, which serves as the electrical connection output terminal, becomes. This shortens the current path, allowing the cylindrical battery to charge and discharge in a shorter time, further improving the battery's charge and discharge efficiency. Furthermore, a thinner end housing portion 120 also aids in heat dissipation. A larger value of b / (a×s) reduces the area of ​​the end housing portion 120, making the cylindrical battery more compact. While this impacts heat dissipation efficiency, testing has proven that it can still meet heat dissipation requirements, effectively controlling battery temperature rise and preventing safety risks associated with high temperature rise.

[0053] The smaller the value of b / (a×s), the thicker the end housing portion 120, which serves as the electrical connection output, becomes. This increases the strength of the end housing portion 120, and while this may lengthen the current path, the limited variation in thickness does not significantly affect the charge and discharge efficiency of the cylindrical battery. The smaller the value of b / (a×s), the larger the area of ​​the end housing portion 120, the greater the heat dissipation area of ​​the cylindrical battery, and the higher the heat dissipation efficiency, which can better control the battery temperature rise and prevent safety risks caused by high temperature rise.

[0054] Based on this, those skilled in the art can select the value of b / (a×s) based on their needs. For example, if a specific heat dissipation device assists in battery heat dissipation, b / (a×s) can be set at 7.4e -14 ~7.5e -4 The larger value is taken in the range. Since other heat dissipation equipment can be used to cool the cylindrical battery, the temperature rise of the cylindrical battery can be suppressed by other heat dissipation equipment. When b / (a×s) takes a large value, the area of ​​the end shell part 120 can be made smaller, making the cylindrical battery more compact. If there is no heat dissipation equipment, b / (a×s) can be set to 7.4e -14 ~7.5e -4 By taking a smaller value within the range, the area of ​​the end shell portion 120 can be made larger, so that the cylindrical battery has a higher heat dissipation efficiency and can better control the battery temperature rise when the external heat dissipation equipment is insufficient.

[0055] In a specific embodiment of the present application, the value range of a can be: 0.15~0.6. Within this value range, the requirements of battery temperature rise and charging and discharging efficiency can be taken into account, which can not only reduce the charging time but also prevent the problem of high battery temperature rise.

[0056] Exemplarily, a can be 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, etc. This embodiment does not limit the specific value of a, that is, the thickness of the end face shell portion 120 serving as the electrical connection output end, and those skilled in the art can choose according to their needs.

[0057] In a specific embodiment of the present application, the value range of s can be: 800~2500. Within this value range, the requirements of battery temperature rise and charging and discharging efficiency can be taken into account. It can avoid the problem of long charging time caused by a long overcurrent path, and can also avoid the problem of increased battery temperature rise due to a small heat dissipation area.

[0058] For example, s can be 800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2300, 2500, etc. This embodiment does not limit the specific value of s, that is, the area of ​​the end surface housing portion 120, and is not limited to the above specific examples. Those skilled in the art can select a value within the range of 800 to 2500 according to their needs.

[0059] In a specific embodiment of the present application, the value range of b can be: 10e -11 ~10e -2 When the value is within this range, the requirements of battery temperature rise and charge and discharge efficiency can be taken into account. It can avoid the problem of excessive battery temperature rise caused by excessive lithium ion transmission, and the problem of prolonged fast charging time caused by obstruction of lithium ion transmission.

[0060] For example, b can be 10e -11 、5e -10 、10e -10 、5e -9 、10e -9 、5e -8 、10e -8 、5e -7 、10e -7 、5e -6 、10e -6 、5e -5 、10e -5 、5e -4 、10e -4 、5e -3 、10e -3 、10e -2 The specific value of b in this embodiment, that is, the powder conductivity of the active material, is not limited to the above specific examples. Those skilled in the art can choose the value of b in the range of 10e -11 ~10e -2 Select within the range.

[0061] like Figure 2 As shown, at least one end surface portion 120 of the battery housing 100 is provided with a terminal 121 electrically connected to the battery cell 200. The terminal 121 serves as the output terminal of the battery current, for transmitting the battery current to the outside. The terminal 121 is used to weld to a conductive member, that is, the terminal 121 is used to pass current.

[0062] In a specific embodiment of the present application, along the radial direction of the end face housing portion 120, the distance from the outer edge of the pole 121 to the outer edge of the end face housing portion 120 is: 10mm~22mm. For example, the distance from the outer edge of the pole 121 to the outer edge of the end face housing portion 120 can be 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, etc. When the diameter of the end face housing portion 120 is constant, the above distance value can reflect the size of the pole 121. In this embodiment, the distance from the outer edge of the pole 121 to the outer edge of the end face housing portion 120 is selected within the range of 10mm~22mm, and the size of the pole 121 can be controlled within an appropriate range to maintain a balance between temperature rise and fast charging time. It can not only ensure that the battery has the ability to charge and discharge in a short time, but also ensure that it has better heat dissipation ability when high current charging and discharging causes increased heat generation.

[0063] like Figure 2 and Figure 4 As shown, when a pole 121 is provided on the end face housing portion 120, a pole recess 1211 is provided on the pole 121. The depth of the pole recess 1211 can range from 0.4 mm to 2 mm. For example, the depth of the pole recess 1211 can be 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, etc. The pole recess 1211 is provided on the outer surface of the pole 121. The bottom wall of the pole recess 1211 is provided with a welding area for welding to the output terminal of the battery cell 200. In other words, the current collecting plate assembly 300 or the tab assembly of the battery cell 200 is welded to the area where the pole recess 1211 is located. Since the pole recess 1211 is provided in this welding area, the current path is shortened. In this embodiment, the depth of the pole recess 1211 is controlled within the range of 0.4 mm to 2 mm to achieve a balance between battery temperature rise and fast charging time. It can not only maintain a suitable overcurrent path to ensure that the battery has the ability to charge and discharge in a short period of time, but also prevent safety risks caused by rapid temperature rise.

[0064] The current collector assembly 300 is a core component in the internal structure of a cylindrical battery. It is typically made of a fan-shaped metal structure such as copper, aluminum, or nickel-plated steel strip. Located at the junction of the positive and negative electrodes and the tabs, it serves as a bridge for current transmission and ensures uniform current distribution.

[0065] The shape and layout of the current collecting plate assembly 300 depend on the battery type, size, and application scenario. Generally speaking, the surface of the current collecting plate assembly 300 is flat, providing ample connection area for the tab assembly. Its surface is also designed with specific connection areas based on the distribution and connection requirements of the tab assembly and the pole post 121 / end face housing portion 120. These areas may be equipped with welding points, rivets, or specialized snap-on structures to ensure a secure connection with the tab assembly, pole post 121, and end face housing portion 120. The current collecting plate assembly 300 serves as a key hub for current conduction within the battery, collecting current from the tab assembly and transmitting it to the pole post 121 / end face housing portion 120. During the battery's charge and discharge process, the current generated by the electrode reaction is collected by the tab assembly and then conducted to the current collecting plate assembly 300 through the current collecting plate assembly 300 to the pole post 121 / end face housing portion 120, thereby establishing a connection with the external circuit. This process ensures stable and efficient current transmission between the battery's interior and exterior.

[0066] It should be noted that the current collecting plate assembly 300 may not be provided, and the tab assembly may be directly connected to the pole 121 / end surface housing portion 120 , which can also realize the transmission of current between the inside and outside of the battery.

[0067] The open end of the pole groove 1211 may be located at the end facing away from the battery cell 200 , and the welding area of ​​the pole 121 is arranged on the bottom wall outside the pole groove 1211 and facing the side of the battery cell 200 .

[0068] The open end of the pole groove 1211 may also be located at the end facing the battery cell 200 , and the welding area of ​​the pole 121 is arranged on the bottom wall within the pole groove 1211 and faces the side of the battery cell 200 .

[0069] The pole grooves 1211 can also be two pole grooves arranged opposite to each other, and the open end of one pole groove 1211 faces the battery cell 200, and the open end of the other pole groove 1211 faces away from the battery cell 200. The two pole grooves 1211 share a bottom wall, and the welding area is set on the bottom wall shared by the two pole grooves 1211 and faces one side of the battery cell 200.

[0070] In a specific embodiment of the present application, the material of the pole 121 can be copper, aluminum, or a copper-aluminum composite material. When the pole 121 is a positive pole, its material can be aluminum. When the pole 121 is a negative pole, its material can be copper or a copper-aluminum composite material. The specific material selection should be based on the polarity of the pole 121. The material of the collecting plate assembly 300 / the tab assembly is generally copper. When the pole 121 is a copper-aluminum composite material, that is, the pole 121 includes a copper layer and an aluminum layer, and the copper layer is arranged near the tab side. The same material has a good welding effect, which is conducive to increasing the overcurrent and reducing heat generation.

[0071] It will be understood by those skilled in the art that a pole insulator is provided around the outer periphery of the pole 121, and the pole insulator is used to insulate the pole 121 from the battery housing. In this embodiment, the thickness of the pole insulator is controlled within the range of 0.2 mm to 1.5 mm. For example, the thickness of the pole insulator can be 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, etc. Experimental verification has shown that when the thickness of the pole insulator is controlled within the range of 0.2 mm to 1.5 mm, the balance between heat dissipation and insulation of the pole 121 can be taken into account, and the influence of the pole insulator on the heat dissipation of the pole 121 can be reduced without affecting the insulation effect.

[0072] The battery cell 200 includes a tab assembly, which can be directly welded to the pole 121, and the area of ​​the welding area is: 10mm 2 ~50mm 2 For example, the welding area between the tab assembly and the pole 121 can be 10 mm 2 , 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 , 35mm 2 , 40mm 2 , 45mm 2 , 50mm 2 wait.

[0073] In addition to this method, the battery cell 200 may also include a tab assembly and a current collecting plate assembly 300. The tab assembly is welded to the pole 121 through the current collecting plate assembly 300, and the area of ​​the welding area is: 10mm 2 ~50mm 2 For example, the welding area between the collecting plate assembly 300 and the pole 121 can be 10mm 2 , 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 , 35mm 2 , 40mm 2 , 45mm 2 , 50mm 2 wait.

[0074] Whether the tab assembly is directly welded to the pole 121 or the tab assembly is welded to the pole 121 through the collector plate assembly 300, the area of ​​the welding region with the pole 121 needs to be controlled. In this embodiment, the area of ​​the welding region is controlled to be 10mm 2 ~50mm 2Within this range, the welding area has appropriate overcurrent capacity and heat-affected zone, which can strike a balance between charging time and thermal stress.

[0075] When the end shell portion 120 is used as one of the positive output terminal and the negative output terminal, the tab assembly of the battery cell 200 can be directly welded to the end shell portion 120 of the battery shell 100, and the area of ​​the welding area is: 10mm 2 ~50mm 2 For example, the welding area between the tab assembly and the end shell portion 120 may be 10 mm 2 , 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 , 35mm 2 , 40mm 2 , 45mm 2 , 50mm 2 .

[0076] In addition to this method, the battery cell 200 may also include a tab assembly and a current collecting plate assembly 300. The tab assembly is welded to the end surface shell portion 120 of the battery shell 100 through the current collecting plate assembly 300, and the area of ​​the welding area is: 10mm 2 ~50mm 2 For example, the welding area between the collecting plate assembly 300 and the end housing portion 120 may be 10 mm 2 , 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 , 35mm 2 , 40mm 2 , 45mm 2 , 50mm 2 .

[0077] Whether the tab assembly is directly welded to the end housing portion 120 or the tab assembly is welded to the end housing portion 120 through the collecting plate assembly 300, the area of ​​the welding region with the end housing portion 120 needs to be controlled. In this embodiment, the area of ​​the welding region is controlled to be 10 mm. 2 ~50mm 2 Within this range, the welding area has appropriate overcurrent capacity and heat-affected zone, which can strike a balance between charging time and thermal stress.

[0078] The tab assembly of the battery cell 200 can be welded directly to the end face housing portion 120 or welded to the end face housing portion 120 via the current collecting plate assembly 300. An end face groove is provided in the area where the end face housing portion 120 is welded to the tab assembly or the current collecting plate assembly 300. The welding area between the end face housing portion 120 and the tab assembly or the current collecting plate assembly 300 is provided on the bottom wall of the end face groove. In this embodiment, the depth of the end face groove is 0.4 mm to 2 mm. For example, the depth of the end face groove can be 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, etc. In this embodiment, the depth of the end face groove is controlled within the range of 0.4 mm to 2 mm, which can strike a balance between battery temperature rise and fast charging time. This can maintain a suitable overcurrent path to ensure that the battery has the ability to charge and discharge in a short period of time, while also preventing safety risks caused by rapid temperature rise.

[0079] In this embodiment, the value range of a can be: 0.15~0.4. For example, a can be 0.15, 0.18, 0.22, 0.24, 0.28, 0.3, 0.33, 0.36, 0.4, etc.

[0080] The open end of the end surface groove may be located at an end facing away from the battery cell 200 , and the welding area is arranged on the bottom wall outside the end surface groove and faces one side of the battery cell 200 .

[0081] The open end of the end surface groove may also be located at the end facing the battery cell 200 , and the welding area is arranged on the bottom wall within the end surface groove and faces one side of the battery cell 200 .

[0082] There can also be two end face grooves arranged opposite to each other, with the open end of one end face groove facing the battery cell 200, and the open end of the other end face groove facing away from the battery cell 200. The two end face grooves share a bottom wall, and the welding area is arranged on the bottom wall shared by the two end face grooves and faces one side of the battery cell 200.

[0083] like Figure 5As shown, a shell insulating member 122 is provided on the side of the end shell portion 120 facing the battery cell 200. The shell insulating member 122 is used to achieve insulation between the battery shell 100 and the battery cell 200. The thickness of the shell insulating member 122 is not less than 0.2 mm. Exemplarily, the thickness of the shell insulating member 122 is: 0.2 mm to 1.5 mm. Specifically, the thickness of the shell insulating member 122 can be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.5 mm, etc. In this embodiment, the thickness of the shell insulating member 122 is controlled within the range of 0.2 mm to 1.5 mm, which can balance the heat dissipation and insulation of the battery. It can reduce the impact of the shell insulating member 122 on the heat dissipation of the battery without affecting the insulation effect.

[0084] When the housing portion insulating member 122 is provided on the side of the end housing portion 120 facing the battery cell 200, the value of a ranges from 0.15 to 0.3. For example, a can be 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, etc.

[0085] like Figure 2 and Figure 3 As shown, in a specific embodiment of the present application, a battery cell 200 includes a tab assembly and a current collecting tray assembly 300. The current collecting tray assembly 300 includes a first current collecting tray 310 and a second current collecting tray 320. The tab assembly includes a positive tab assembly and a negative tab assembly. One of the first current collecting tray 310 and the second current collecting tray 320 is electrically connected to the positive tab assembly, and the other is electrically connected to the negative tab assembly. It should be noted that the first current collecting tray 310 and the second current collecting tray 320 are generally mounted on a current collecting tray insulating frame 330 to achieve insulation between the first current collecting tray 310 and the second current collecting tray 320, while also facilitating the fixing of the first current collecting tray 310 and the second current collecting tray 320 and maintaining their stability.

[0086] One of the first current collecting disc 310 and the second current collecting disc 320 is electrically connected to the positive electrode tab assembly, and the other is electrically connected to the negative electrode tab assembly, so that one of the first current collecting disc 310 and the second current collecting disc 320 is a positive electrode current collecting disc and the other is a negative electrode current collecting disc.

[0087] The positive and negative output terminals of a cylindrical battery can both be terminals, or one of them can be a terminal and the other a terminal housing portion 120. One of the first and second current collecting discs 310 and 320 is welded to the positive output terminal, while the other is welded to the negative output terminal (one of the first and second current collecting discs 310 and 320 is a positive current collecting disc, while the other is a negative current collecting disc). Exemplarily, a terminal 121 is provided on one of the terminal housing portions 120 of the battery housing 100. One of the first and second current collecting discs 310 and 320 is electrically connected to the terminal 121, while the other is electrically connected to the terminal housing portion 120 on which the terminal 121 is provided.

[0088] When the terminal post 121 functions as the positive electrode, the end housing portion 120 functions as the negative electrode. The terminal post 121, as the positive electrode, is connected to the positive electrode current collector disc, while the end housing portion 120, as the negative electrode, is connected to the negative electrode current collector disc. When the terminal post 121 can also function as the negative electrode, the end housing portion 120 functions as the positive electrode. The terminal post 121, as the negative electrode, is connected to the negative electrode current collector disc, while the end housing portion 120, as the positive electrode, is connected to the positive electrode current collector disc.

[0089] To accelerate heat dissipation from the first current collecting tray 310, in this embodiment, first through-holes 311 are provided on the first current collecting tray 310. The number of first through-holes 311 can range from 2 to 8. For example, the number of first through-holes 311 can be 2, 3, 4, 5, 6, 7, 8, etc. Those skilled in the art can select the actual number of first through-holes 311 based on their needs. This embodiment does not limit the specific number of first through-holes 311. In this embodiment, the number of first through-holes 311 is controlled within the range of 2 to 8 to ensure improved heat dissipation from the first current collecting tray 310 without affecting the battery fast charging time.

[0090] To accelerate heat dissipation from the second current collecting tray 320, in this embodiment, second through-holes 321 are provided on the second current collecting tray 320. The number of second through-holes 321 ranges from 2 to 8. For example, the number of second through-holes 321 can be 2, 3, 4, 5, 6, 7, 8, etc. Those skilled in the art can select the actual number of second through-holes 321 based on their needs. This embodiment does not limit the specific number of second through-holes 321. In this embodiment, the number of second through-holes 321 is controlled within the range of 2 to 8 to ensure improved heat dissipation from the second current collecting tray 320 without affecting the battery's fast charging time.

[0091] Furthermore, the area of ​​the first through hole 311 can be 2mm²~12mm². Exemplarily, the area of ​​the first through hole 311 can be 2mm², 4mm², 5mm², 6mm², 10mm², 12mm², etc. Those skilled in the art can select the actual area of ​​the first through hole 311 according to their needs. This embodiment does not limit the specific area of ​​the first through hole 311. The specific area of ​​the first through hole 311 is not limited to the specific values ​​listed above and can be arbitrarily selected within the range of 2mm²~12mm². In this embodiment, the area of ​​the first through hole 311 is controlled within the range of 2mm²~12mm², so that the area of ​​the first through hole 311 can reduce the impact on the fast charging time of the battery while ensuring the heat dissipation effect.

[0092] The area of ​​the second through hole 321 can be 2mm²~12mm². Exemplarily, the area of ​​the second through hole 321 can be 2mm², 4mm², 5mm², 6mm², 10mm², 12mm², etc. Those skilled in the art can select the actual area of ​​the second through hole 321 according to their needs. This embodiment does not limit the specific area of ​​the second through hole 321. The specific area of ​​the second through hole 321 is not limited to the specific values ​​listed above and can be arbitrarily selected within the range of 2mm²~12mm². In this embodiment, the area of ​​the second through hole 321 is controlled within the range of 2mm²~12mm², so that the area of ​​the second through hole 321 can reduce the impact on the fast charging time of the battery while ensuring the heat dissipation effect.

[0093] In a specific embodiment of the present application, the battery cell 200 includes a tab assembly, which includes a positive tab assembly and a negative tab assembly. Since the positive tab assembly and the negative tab assembly are used to pass current, when the positive tab assembly and the negative tab assembly are located on the same side of the battery housing 100, the temperature rise will be greater. Based on this, in this embodiment, the value range of a is controlled to be: 0.15~0.5, and the value range of s is controlled to be: 1200~2500. The value range of a can be 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, etc. Those skilled in the art can select the actual thickness of the end face housing portion 120 according to needs. This embodiment does not limit the specific thickness of the end face housing portion 120. The value range of s can be 1200, 1400, 1600, 1800, 2000, 2200, 2300, 2500, etc. This embodiment does not limit the specific value of s, that is, the area of ​​the end face shell portion 120, and technical personnel in this field can choose according to needs.

[0094] In this embodiment, a and s are set within the above-mentioned range, that is, the thickness of the end face shell portion 120 is set within a small value range, which can reduce the thickness of the end face shell portion 120 to accelerate heat dissipation; at the same time, the area of ​​the end face shell portion 120 is set within a large value range, that is, the area of ​​the end face shell portion 120 is increased to increase the heat exchange area and accelerate heat dissipation.

[0095] In another specific embodiment of the present application, the battery cell 200 includes a tab assembly, which includes a positive tab assembly and a negative tab assembly. Since the positive tab assembly and the negative tab assembly are used to pass current, when the positive tab assembly and the negative tab assembly are respectively located on both sides of the battery housing 100, the heat generation will be small and the temperature rise will be low. Based on this, in this embodiment, the value range of a is controlled to be: 0.2~0.6, and the value range of s is controlled to be: 800~2200. The value range of a can be 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, etc. Those skilled in the art can select the actual thickness of the end face housing portion 120 according to needs. This embodiment does not limit the specific thickness of the end face housing portion 120. The value range of s can be 800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, etc. This embodiment does not limit the specific value of s, that is, the area of ​​the end face shell portion 120, and technical personnel in this field can choose according to needs.

[0096] In this embodiment, a and s are taken within the above-mentioned range, that is, the thickness of the end face shell portion 120 is taken within a large value range, and the thickness of the end face shell portion 120 can be increased as needed to improve the strength of the end face shell portion 120; at the same time, the area of ​​the end face shell portion 120 is taken within a small value range, that is, the area of ​​the end face shell portion 120 is reduced to keep the cylindrical battery compact.

[0097] In a specific embodiment of the present application, the battery cell 200 includes a tab assembly, and the tab assembly includes a positive tab assembly and a negative tab assembly.

[0098] The positive tab assembly includes multiple stacked monolithic tabs. Correspondingly, the negative tab assembly also includes multiple stacked monolithic tabs. Monolithic tabs (both the positive and negative tabs) are typically thin metal tabs extending from the positive and negative electrode sheets of the battery cell 200. One end of the tab is connected to the electrode sheet inside the battery cell, and the other end is connected to the terminal / end face housing portion 120 (i.e., the electrical connection output terminal) on the battery casing. The function of the monolithic tab is to conduct current from the battery cell 200 and collect it at the electrical connection output terminal, thereby connecting the battery cell to the external circuit.

[0099] Along the axial direction of the cylindrical battery, the stacking thickness of the positive electrode tab assembly is: 0.2mm~3.5mm. Exemplarily, the stacking thickness of the positive electrode tab assembly can be 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.3mm, 1.6mm, 2.0mm, 2.5mm, 2.8mm, 3.0mm, 3.2mm, 3.5mm, etc. This embodiment does not limit the specific stacking thickness of the positive electrode tab assembly, and is not limited to the above-mentioned specific values. Those skilled in the art can choose within the range of 0.2mm~3.5mm according to their needs. In this embodiment, the stacking thickness of the positive electrode tab assembly is controlled within the range of 0.2mm~3.5mm, which can take into account the balance between the battery temperature rise and the fast charging time. The stacking thickness of the positive electrode tab assembly enables the positive electrode tab assembly to have a suitable overcurrent path, which ensures that the battery has the ability to charge and discharge in a short time while avoiding the problem of large battery temperature rise.

[0100] In addition, in the axial direction of the cylindrical battery, the stacking thickness of the negative electrode tab assembly is: 0.2mm~3.5mm. Exemplarily, the stacking thickness of the negative electrode tab assembly can be 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.3mm, 1.6mm, 2.0mm, 2.5mm, 2.8mm, 3.0mm, 3.2mm, 3.5mm, etc. This embodiment does not limit the specific stacking thickness of the negative electrode tab assembly, and is not limited to the above-mentioned specific values. Those skilled in the art can choose within the range of 0.2mm~3.5mm according to their needs. In this embodiment, the stacking thickness of the negative electrode tab assembly is controlled within the range of 0.2mm~3.5mm, which can take into account the balance between the battery temperature rise and the fast charging time. The stacking thickness of the negative electrode tab assembly enables the negative electrode tab assembly to have a suitable overcurrent path, which ensures that the battery has the ability to charge and discharge in a short time while avoiding the problem of large battery temperature rise.

[0101] In another embodiment of the present application, the lead-out dimension of the positive tab assembly (i.e., the length of the positive tab assembly extending out of the battery cell 200, i.e., the distance between the end of the positive tab assembly closest to the battery cell and the end further away from the battery cell) is 3 mm to 10 mm. For example, the lead-out dimension of the positive tab assembly can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. This embodiment does not limit the specific lead-out dimension of the positive tab assembly, and is not limited to the specific values ​​listed above. Those skilled in the art can select a dimension within the range of 3 mm to 10 mm based on their needs. In this embodiment, controlling the lead-out dimension of the positive tab assembly within the range of 3 mm to 10 mm can achieve a balance between battery temperature rise and fast charging time. The lead-out dimension of the positive tab assembly provides a suitable current path for the positive tab assembly, ensuring the battery's ability to charge and discharge quickly while avoiding the problem of large battery temperature rise.

[0102] In addition, the lead-out dimension of the negative electrode tab assembly (i.e., the length of the negative electrode tab assembly extending out of the battery cell 200, i.e., the distance between the end of the negative electrode tab assembly close to the battery cell and the end away from the battery cell) is: 3mm~10mm. Exemplarily, the lead-out dimension of the negative electrode tab assembly can be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. This embodiment does not limit the specific lead-out dimension of the negative electrode tab assembly, and is not limited to the specific values ​​listed above. Those skilled in the art can select within the range of 3mm~10mm according to their needs. In this embodiment, the lead-out dimension of the negative electrode tab assembly is controlled within the range of: 3mm~10mm, which can take into account the balance between the battery temperature rise and the fast charging time. The lead-out dimension of the negative electrode tab assembly enables the negative electrode tab assembly to have a suitable overcurrent path, which avoids the problem of large battery temperature rise while ensuring that the battery has the ability to charge and discharge in a short time. As Figure 4 As shown, the battery cell 200 has a core hole 201, and the diameter range of the core hole 201 is: 4mm~10mm. Exemplarily, the diameter range of the core hole 201 can be 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. This embodiment does not limit the specific diameter of the core hole 201, and is not limited to the specific values ​​listed above. Those skilled in the art can choose within the range of 4mm~10mm according to their needs. In this embodiment, the diameter of the core hole 201 is controlled within the range of 4mm~10mm, which can take into account the balance between battery temperature rise and battery capacity. On the basis of ensuring the battery capacity, it is ensured that there is sufficient heat dissipation space to prevent excessive temperature rise.

[0103] In a specific embodiment of the present application, the compaction density of the positive electrode sheet can be in the range of: 2.3 g / cm 3 ~3.8g / cm 3For example, the compaction density of the positive electrode sheet can be 2.3 g / cm 3 , 2.5g / cm 3 , 2.8 g / cm 3 , 3.0g / cm 3 , 3.5g / cm 3 、3.8g / cm 3 Etc. This embodiment does not limit the specific compaction density of the positive electrode sheet, and is not limited to the specific values ​​listed above. Those skilled in the art can select within the range of 2.3g / cm³ to 3.8g / cm³ according to their needs. In this embodiment, the compaction density of the positive electrode sheet is controlled within the range of 2.3g / cm³ to 3.8g / cm³, which can balance the battery temperature rise and fast charging time, and prevent the problem of large battery temperature rise without reducing the powder conductivity.

[0104] In a specific embodiment of the present application, an explosion-proof valve is provided on the battery housing 100. The explosion-proof valve and the pole 121 may be located on the same end housing portion 120, or the explosion-proof valve and the pole 121 may be located on different end housing portions 120. When the explosion-proof valve and the pole 121 are located on the same end housing portion 120, the residual thickness of the explosion-proof valve may range from 0.04 mm to 0.3 mm. For example, the residual thickness of the explosion-proof valve may be 0.04 mm, 0.08 mm, 0.12 mm, 0.16 mm, 0.20 mm, 0.24 mm, 0.28 mm, 0.3 mm, etc. The specific residual thickness value of the explosion-proof valve can be selected by those skilled in the art according to actual needs.

[0105] When the explosion-proof valve and the pole 121 are located in different end surface shell parts 120, the residual thickness range of the explosion-proof valve is: 0.04mm~0.35mm. For example, the residual thickness of the explosion-proof valve can be 0.04mm, 0.08mm, 0.12mm, 0.16mm, 0.20mm, 0.24mm, 0.28mm, 0.3mm, 0.35mm, etc. The specific residual thickness value of the explosion-proof valve can be selected by those skilled in the art according to actual needs.

[0106] When the explosion-proof valve and the terminal 121 are located in the same end housing portion 120, the space for the explosion-proof valve is squeezed by the terminal 121, resulting in limited installation space. Therefore, the explosion-proof valve area cannot be sufficiently large. Therefore, the upper limit of the residual thickness of the explosion-proof valve can be reduced to ensure that the explosion-proof valve can function in the event of thermal runaway. When the explosion-proof valve and the terminal 121 are located in different end housing portions 120, the explosion-proof valve can be larger and the upper limit of the residual thickness of the explosion-proof valve can be set higher.

[0107] In a specific embodiment of the present application, the positive electrode material may include a positive electrode active material, and the positive electrode active material is selected from at least one of lithium iron phosphate (LiFePO4), lithium manganese iron phosphate (LMFP), ternary NCA (lithium nickel cobalt aluminum oxide) and ternary NCM (lithium nickel cobalt manganese oxide).

[0108] When the positive electrode active material includes lithium iron phosphate, the preferred range of s is 800 to 2200. For example, the specific value of s can be 800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, etc., and those skilled in the art can select it according to needs.

[0109] When the positive electrode active material includes lithium iron phosphate, the value range of a is: 0.15~0.5. For example, the specific value of a can be 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, etc. Those skilled in the art can select the actual thickness of the end face shell portion 120 according to needs.

[0110] Since the temperature rise of the lithium iron phosphate system is relatively small, the area of ​​the end face shell portion 120 can also be smaller, that is, the upper limit value of the area range of the end face shell portion 120 can be reduced, so that the end face shell portion 120 can take a value within a smaller area range, which can also meet the use requirements.

[0111] When the positive electrode active material includes lithium iron phosphate, the average particle size D50 of the positive electrode active material can be: 0.5μm~2μm. For example, the average particle size D50 of the positive electrode active material can be 0.5μm, 0.8μm, 1.0μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, 2μm, etc., and those skilled in the art can select according to needs. In this embodiment, the average particle size D50 of the positive electrode active material is controlled within the range of 0.5μm~2μm, which can balance the fast charging time and battery temperature rise.

[0112] When the positive electrode active material includes a ternary NCM, the value of s ranges from 1200 to 2500. For example, the value of s can range from 1200, 1400, 1600, 1800, 2000, 2200, 2300, 2500, etc. This embodiment does not limit the specific value of s, that is, the area of ​​the end surface shell portion 120. Those skilled in the art can select a value within the range of 1200 to 2500 as needed.

[0113] Since the temperature rise of the ternary NCM is relatively large, the area of ​​the end face shell part 120 can be larger, that is, the lower limit of the area range of the end face shell part 120 can be increased, so that the end face shell part 120 can take a value within a larger area range to meet usage requirements.

[0114] In the case where the positive electrode active material includes a ternary NCM, the average particle size D50 of the positive electrode active material can be: 2μm~20μm. Exemplarily, the average particle size D50 of the positive electrode active material can be 2μm, 4μm, 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, etc. This embodiment does not limit the specific value of the average particle size D50 of the positive electrode active material, and those skilled in the art can select it within the range of 2μm~20μm according to needs. This embodiment controls the average particle size D50 of the positive electrode active material within the range of 2μm~20μm, which can take into account the balance between fast charging time and battery temperature rise.

[0115] The present application can prepare the cylindrical battery by conventional methods in the art, for example, including the following steps:

[0116] (1) Preparation of negative electrode sheet

[0117] The negative electrode active material is mixed with additives and a solvent is added to produce a negative electrode slurry. The negative electrode slurry is then coated on at least one surface of the negative electrode current collector, dried, roll-pressed, and slit to produce the negative electrode sheet. Additives include conductive agents, binders, and thickeners. The negative electrode active material can include one or more of natural graphite, artificial graphite, silicon, silicon oxide, and silicon carbon.

[0118] The mass ratios of the negative electrode active material, conductive agent, thickener, and binder are conventional in the art. For example, the mass ratios of the negative electrode active material, conductive agent, dispersant, and binder are (96.7-97.95): (0.5-1): (0.05-0.3): (1.5-2). The conductive agent, dispersant, binder, and thickener are commonly used in the art. For example, the conductive agent can be one or more of acetylene black and single-walled carbon nanotubes (SWCNTs); the thickener can be CMC (carboxymethyl cellulose); and the binder can be SBR (polymerized styrene butadiene rubber). The current collector can be a composite current collector or a metal foil, such as Cu foil.

[0119] (2) Preparation of positive electrode

[0120] The positive electrode active material and additives are mixed and a solvent is added to produce a positive electrode slurry. The positive electrode slurry is then coated on at least one surface of a positive electrode current collector, dried, rolled, and slit to produce a positive electrode sheet. Additives include conductive agents, dispersants, and binders.

[0121] The amounts of positive electrode active material, conductive agent, dispersant, binder, and solvent can be selected based on specific needs in this field. For example, the mass ratio of positive electrode active material, conductive agent, dispersant, and binder is (96-96.5):(0.5-1):(0.4-1.8):(1.2-2.6). The conductive agent and binder are commonly used materials in this field. For example, the conductive agent can be one or more of acetylene black, SWCNT, etc.; the binder can be SBR, etc. The current collector can be a composite current collector or a metal foil, such as Al foil.

[0122] (3) Preparation of electrolyte

[0123] The electrolyte can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent, and typically includes a lithium salt. The concentration of the lithium salt in the electrolyte is 0.5 to 2.5 mol / L.

[0124] Conventional lithium salts in the art are used as examples. The lithium salt is at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalatophosphate) (LiDFOP), and lithium tetrafluorooxalatophosphate (LiTFOP).

[0125] The solvent can be one or more components such as cyclic carbonates (fluoroethylene carbonate (FEC), propylene carbonate (PC), ethylene carbonate (EC)), linear carbonates (dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC)), carboxylic acid esters (methyl propionate (MP)), etc.

[0126] (4) Preparation of diaphragm

[0127] The separator is placed between the positive and negative electrodes to separate them and prevent short circuits. This application does not specify the manufacturer, preparation process, or type of separator. For example, the separator can be made of polyethylene (PE) or polypropylene (PP).

[0128] (5) The positive electrode sheet, separator, and negative electrode sheet are stacked in order and wound to obtain a bare cell; the bare cell is placed in an outer packaging shell, dried, injected with electrolyte, and packaged, allowed to stand, and formed to obtain a lithium-ion battery.

[0129] like Figure 6As shown, the embodiment of the present application also discloses a battery pack, including the cylindrical battery 10 disclosed in the above embodiment. The battery pack disclosed in the embodiment of the present application, because it has the above cylindrical battery 10, has all the technical effects of the above cylindrical battery 10, which will not be described in detail here. It should be noted that the battery pack can be used as Figure 6 The start-stop power supply shown in the figure can of course also be used in other fields.

[0130] The present application also discloses an electrical device comprising the battery pack disclosed in the above embodiment. The electrical device may be an electric vehicle, an electric ship, an aircraft, an energy storage device, or the like. The electrical device disclosed in the present application, because it includes the above battery pack, has all the technical effects of the above battery pack, which will not be further described herein.

[0131] In order to verify the technical effects of the battery cell disclosed in the embodiments of the present application, a temperature rise test and a fast charging time test were conducted on the battery cell. The specific test results are detailed in Table 1.

[0132] In order to complete the temperature rise test and fast charge time test of the battery cell, the battery to be tested needs to be prepared. The specific preparation process is as follows.

[0133] The powder conductivity of the positive electrode material can be adjusted by regulating the particle size of the positive electrode active material and the compaction density of the positive electrode sheet.

[0134] The preparation process of the battery disclosed in Example 1 in Table 1 is described below.

[0135] (1) Positive electrode

[0136] The preparation process of the positive electrode sheet is as follows: the positive electrode active material lithium iron phosphate (LiPFeO4), binder, polyvinylidene fluoride (PVDF), conductive agent superconducting carbon (SP), and dispersant sodium carboxymethyl cellulose (CMC-Na) are mixed evenly in a mass ratio of 96.2:0.8:1.0:2.0, and the solvent NMP (N-methylpyrrolidone) 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 coated on aluminum foil to obtain a double-sided coated positive electrode sheet; then, the positive electrode sheet is obtained by rolling and cutting; the surface density of the positive electrode sheet is 400g / m 2 , with a thickness of 120μm.

[0137] (2) Negative electrode

[0138] The preparation process of the negative electrode sheet is as follows: graphite is mixed with the conductive agent superconducting carbon (SP), the dispersant sodium carboxymethyl cellulose (CMC), and the binder polyvinylidene fluoride (PVDF) in a mass ratio of 97.4:0.6:0.2:1.8, and dispersed in deionized water to obtain a negative electrode slurry; the negative electrode slurry is coated on copper foil to obtain a double-sided coated electrode sheet; then, the negative electrode sheet is rolled and cut to obtain a negative electrode sheet; the surface density of the negative electrode sheet is 180g / m 2 , with a thickness of 120μm.

[0139] (3) Electrolyte

[0140] The preparation process of the electrolyte is as follows: 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, and then the fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte; the LiPF6 concentration in the electrolyte is 1 mol / L.

[0141] (4) Diaphragm

[0142] The preparation process of the diaphragm is as follows: PE is selected as the base membrane, Al2O3 is selected as the coating, the adhesive layer is polyvinylidene fluoride (PVDF), an adhesive layer is provided on one side of the base membrane, and the other layer is provided with a coating and an adhesive layer in sequence. The diaphragm specification is 2+9+3+2 (adhesive layer + base membrane + coating + adhesive layer, μm).

[0143] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed between the positive and negative electrode sheets to serve as an isolation, and then wound to obtain a bare cell; the bare cell is placed in an outer packaging shell, dried, and then injected with electrolyte, and after vacuum packaging, standing, forming, shaping and other processes, a lithium-ion battery is obtained.

[0144] The preparation process of the battery disclosed in Example 6 in Table 1 is described below.

[0145] The preparation process of the positive electrode sheet is as follows: the positive electrode active material lithium nickel cobalt manganese oxide (NCM), the conductive agent acetylene black, and the binder PVDF are mixed in a mass ratio of 98.2:0.7:1.1, the solvent NMP is added, and the system is stirred under the action of a vacuum mixer until the system becomes uniform to obtain a positive electrode slurry, and the slurry is evenly coated on both sides of the positive electrode current collector aluminum foil to obtain a double-sided coated positive electrode sheet; then, the positive electrode sheet is obtained by rolling and cutting; the surface density of the positive electrode sheet is 400g / m 2 , with a thickness of 120μm.

[0146] It should be noted that the preparation process of the negative electrode sheet, the preparation process of the electrolyte, and the preparation process of the separator are the same as the preparation process of the battery disclosed in the above embodiment 1, and will not be repeated here.

[0147] In addition, the preparation methods of batteries with the same positive electrode active materials are also the same, and the preparation methods of batteries with the same positive electrode active materials in Table 1 will not be described in detail herein.

[0148] Standing, forming, and volume setting processes

[0149] The battery obtained in each embodiment and comparative example was dried and injected, and after standing at a high temperature of 45 ℃ for 24h, the glass clamp was clamped with a pressure of 0.4-0.6MPa;

[0150] At 45°C, perform the following operations:

[0151] 1) Let it sit for 10 minutes;

[0152] 2) Charge at a rate of 0.02C for 300 minutes and then stop;

[0153] 3) Let it sit for 10 minutes,

[0154] 4) Charge at a rate of 0.1C for 300 minutes and then stop;

[0155] 5) End.

[0156] After being placed at 45℃ for 24 hours and sealed twice, the volume setting step is carried out.

[0157] The following describes the test method for the powder conductivity of the positive electrode material:

[0158] 1) Discharge: After recording the battery number / barcode, use a battery charging and discharging device to discharge the battery. Discharge conditions: current 0.3C, cut-off voltage 2.5V;

[0159] 2) Disassembly and cleaning: Disassemble the battery in a dew-point controlled room, remove the positive electrode, and soak it in a polytetrafluoroethylene box filled with DMC (dimethyl carbonate) solvent for 24 hours. Then remove the positive electrode and bake the cleaned electrode at 60°C for 4 hours to remove the residual DMC solvent. This will give the positive electrode to be tested.

[0160] 3) Powder scraping: Scrape the powder from the positive electrode to be tested, grind the scraped powder gently with a mortar to eliminate lumps in the powder, and collect the powder for testing;

[0161] 4) Testing: The collected powder sample is placed in the sample cell of the YK22-FT-300II powder conductivity meter to test the powder conductivity and obtain the powder conductivity of the positive electrode active material layer.

[0162] The specific process of conducting temperature rise test and fast charge time test on battery cells is as follows.

[0163] The temperature rise test method is: charge the battery at a constant current of 20C for 10s at a rate of 25±2℃. During the process, detect the temperature of the battery surface and terminals, and measure the battery temperature rise value. The maximum temperature rise is required to be less than or equal to 30℃.

[0164] The test method for fast charging time is: the time required for the battery to be charged to a cut-off voltage of 3.65V at a constant current rate of 15C. The fast charging time is required to be less than or equal to 180s.

[0165] Table 1 Comparison of battery temperature rise test and fast charge time test

[0166]

[0167] In Examples 1 to 7, the thickness of the end shell portion where it is electrically connected to the battery cell, the conductivity of the positive electrode material powder, and the area of ​​the end shell portion all meet the specified ranges (the value range of a is 0.15 to 0.6; the value range of s is 800 to 2500; the value range of b is 10e -11 ~10e -2 ), b / (a×s) also meets the limited range (the range of b / (a×s) is: 7.4e -14 ~7.5e -4 ), cylindrical batteries have short fast charging time, small temperature rise and high battery safety.

[0168] In Examples 8 to 13, at least one of the three parameters, the thickness of the end shell portion in the area electrically connected to the battery cell, the powder conductivity of the positive electrode material, and the area of ​​the end shell portion, is not within the range (the value range of a is: 0.15-0.6; the value range of s is: 800-2500; the value range of b is: 10e -11 ~10e -2 ), but b / (a×s) meets the limited range (the range of b / (a×s) is: 7.4e -14 ~7.5e -4 The battery's fast-charge time and temperature rise also meet the requirements, but are slightly worse than those where both parameters and b / (a×s) meet the specified range. The ternary NCM battery has a shorter fast-charge time than the LFP battery, but its temperature rise is higher than that of the LFP battery.

[0169] In Comparative Examples 1 and 2, at least one of the three parameters, the thickness of the end shell portion in the area electrically connected to the battery cell, the powder conductivity of the positive electrode material, and the area of ​​the end shell portion, is not within the specified range (the value range of a is 0.15-0.6; the value range of s is 800-2500; the value range of b is 10e -11 ~10e -2 ), b / (a×s) does not meet the range (the range of b / (a×s) is: 7.4e -14 ~7.5e-4 ).

[0170] In Comparative Example 1, b / (a×s) exceeded the maximum value, the temperature rise was greater than 30°C, and the battery safety was poor;

[0171] In Comparative Example 2, b / (a×s) is less than the minimum value, and the battery fast charging time is extended to greater than 180s.

[0172] For comparative examples 3 and 4, the thickness of the end shell portion in the region electrically connected to the battery cell, the conductivity of the powder of the positive electrode material, and the area of ​​the end shell portion all meet the specified ranges (the value range of a is 0.15-0.6; the value range of s is 800-2500; the value range of b is 10e -11 ~10e -2 ), b / (a×s) does not meet the range (the range of b / (a×s) is: 7.4e -14 ~7.5e -4 ).

[0173] In Comparative Example 4, b / (a×s) exceeded the maximum value, the temperature rise was greater than 30°C, and the battery safety was poor;

[0174] In Comparative Example 3, b / (a×s) is less than the minimum value, and the battery fast charging time is extended to greater than 180s.

[0175] Unless the context clearly indicates an exception, the terms "a," "an," "an," and / or "the" are not intended to refer to the singular and may include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The phrase "comprises a..." does not preclude the presence of additional identical elements in the process, method, product, or apparatus that includes the elements.

[0176] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0177] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0178] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core ideas of this application. It should be noted that for those skilled in the art, without departing from the principles of this application, various improvements and modifications can be made to this application, and such improvements and modifications also fall within the scope of protection of the claims of this application.

Claims

1. A cylindrical battery, characterized in that: The invention comprises a battery housing (100) and a battery cell (200) arranged in the battery housing (100), wherein the battery housing (100) comprises an outer peripheral housing portion (110) and end surface housing portions (120) located at both ends of the outer peripheral housing portion (110), at least one end surface housing portion (120) along the axial direction of the cylindrical battery is an electrical connection output end, the thickness of the region where the end surface housing portion (120) serving as the electrical connection output end is electrically connected to the battery cell (200) is a millimeter, and the area of ​​the end surface housing portion (120) is s square millimeters; The battery cell (200) comprises a positive electrode sheet having a positive electrode material, wherein the powder conductivity of the positive electrode material is b Siemens per millimeter, and the value range of b / (a×s) is: 7.4e -14 ~7.5e -4 .

2. The cylindrical battery according to claim 1, wherein: The value range of a is: 0.15~0.6; And / or, the value range of s is: 800~2500; And / or, the value range of b is: 10e -11 ~10e -2 .

3. The cylindrical battery according to claim 1, wherein: The battery cell (200) includes a tab assembly, the tab assembly is welded to the end surface shell portion (120) of the battery shell (100), and the area of ​​the welding region is: 10mm 2 ~50mm 2 ; or, The battery cell (200) comprises a tab assembly and a current collecting plate assembly (300), the tab assembly being welded to the end surface housing portion (120) of the battery housing (100) via the current collecting plate assembly (300), and the area of ​​the welding region is: 10 mm 2 ~50mm 2 .

4. The cylindrical battery according to claim 3, wherein: The end surface housing portion (120) is provided with an end surface groove, and a welding area between the end surface housing portion (120) and the tab assembly or the current collecting plate assembly (300) is provided on the bottom wall of the end surface groove.

5. The cylindrical battery according to claim 4, wherein: The depth of the end surface groove is: 0.4mm~2mm; and / or, The value range of a is: 0.15~0.

4.

6. The cylindrical battery according to claim 4, wherein: The open end of the end surface groove is located at an end facing away from the battery core (200), and the welding area is arranged on the bottom wall outside the end surface groove and faces one side of the battery core (200); or, The open end of the end surface groove is located at an end facing the battery core (200), and the welding area is arranged on the bottom wall within the end surface groove and faces one side of the battery core (200); or, There are two end surface grooves arranged opposite to each other, and the open end of one of the end surface grooves faces the battery cell (200), and the open end of the other end surface groove faces away from the battery cell (200), the two end surface grooves share a bottom wall, and the welding area is provided on the bottom wall shared by the two end surface grooves and faces one side of the battery cell (200).

7. The cylindrical battery according to claim 1, wherein: A pole (121) is provided on at least one end surface housing portion (120) of the battery housing (100), the pole (121) being electrically connected to the battery core (200), and a distance from an outer edge of the pole (121) to an outer edge of the end surface housing portion (120) along a radial direction of the end surface housing portion (120) is 10 mm to 22 mm.

8. The cylindrical battery according to claim 1, wherein: A pole (121) is provided on at least one end surface shell portion (120) of the battery shell (100), the pole (121) being electrically connected to the battery cell (200), the pole (121) being provided with a pole groove (1211), and the bottom wall of the pole groove (1211) being provided with a welding area welded to the battery cell output end of the battery cell (200).

9. The cylindrical battery according to claim 8, wherein: The depth of the pole groove (1211) ranges from 0.4 mm to 2 mm.

10. The cylindrical battery according to claim 8, wherein: The open end of the pole groove (1211) is located at an end facing away from the battery cell (200), and the welding area is arranged on the bottom wall outside the pole groove (1211) and faces one side of the battery cell (200); or, The open end of the pole groove (1211) is located at an end facing the battery core (200), and the welding area is provided on the bottom wall within the pole groove (1211) and faces a side of the battery core (200); or, The two pole grooves (1211) are arranged opposite to each other, and the open end of one of the pole grooves (1211) faces the battery cell (200), and the open end of the other pole groove (1211) faces away from the battery cell (200); the two pole grooves (1211) share a bottom wall, and the welding area is provided on the bottom wall shared by the two pole grooves (1211) and faces one side of the battery cell (200).

11. The cylindrical battery according to claim 1, wherein: A pole (121) is provided on at least one end surface shell portion (120) of the battery shell (100), the pole (121) is electrically connected to the battery core (200), and the material of the pole (121) is copper, aluminum, or a copper-aluminum composite material.

12. The cylindrical battery according to claim 1, wherein: A pole (121) is provided on at least one end surface shell portion (120) of the battery shell (100), the pole (121) is electrically connected to the battery core (200), and a pole insulating member is provided on the outer periphery of the pole (121), wherein the thickness of the pole insulating member ranges from 0.2 mm to 1.5 mm.

13. The cylindrical battery according to claim 1, wherein: A pole (121) is provided on at least one end surface housing portion (120) of the battery housing (100); The battery cell (200) includes a tab assembly, the tab assembly is welded to the pole (121), and the area of ​​the welding region is: 10 mm 2 ~50mm 2 Alternatively, the battery cell (200) includes a tab assembly and a current collecting plate assembly (300), the tab assembly is welded to the pole (121) via the current collecting plate assembly (300), and the area of ​​the welding region is: 10 mm 2 ~50mm 2 .

14. The cylindrical battery according to claim 1, wherein: The end surface housing portion (120) is provided with a housing portion insulating member (122), and the housing portion insulating member (122) is used to achieve insulation between the battery housing (100) and the battery core (200).

15. The cylindrical battery according to claim 14, wherein: Along the axial direction of the cylindrical battery, the thickness of the shell insulating member (122) is not less than 0.2 mm; and / or, The value range of a is: 0.15~0.

3.

16. The cylindrical battery according to claim 1, wherein: The battery cell (200) comprises a tab assembly and a current collecting disc assembly (300), the current collecting disc assembly (300) comprising a first current collecting disc (310) and a second current collecting disc (320), the tab assembly comprising a positive tab assembly and a negative tab assembly, one of the first current collecting disc (310) and the second current collecting disc (320) being electrically connected to the positive tab assembly, and the other being electrically connected to the negative tab assembly; The first current collecting disc (310) is provided with first through holes (311), and the number of the first through holes (311) is 2 to 8; and / or the second current collecting disc (320) is provided with second through holes (321), and the number of the second through holes (321) is 2 to 8.

17. The cylindrical battery according to claim 16, wherein: The area of ​​each of the first through holes (311) is 2 mm² to 12 mm²; and / or the area of ​​each of the second through holes (321) is 2 mm² to 12 mm².

18. The cylindrical battery according to claim 16, wherein: A pole (121) is provided on one of the end surface shell parts (120) of the battery shell (100); one of the first current collecting disc (310) and the second current collecting disc (320) is electrically connected to the pole (121), and the other is electrically connected to the end surface shell part (120) provided with the pole (121).

19. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The battery cell (200) includes a tab assembly, the tab assembly including a positive tab assembly and a negative tab assembly, the positive tab assembly and the negative tab assembly are located on the same side of the battery housing (100) in the axial direction, and the value range of s is: 1200~2500.

20. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The battery cell (200) includes a tab assembly, wherein the tab assembly includes a positive tab assembly and a negative tab assembly, wherein the positive tab assembly and the negative tab assembly are respectively located on two sides of the battery housing (100) in the axial direction, and the value range of s is 800-2200.

21. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The battery cell (200) comprises a tab assembly, wherein the tab assembly comprises a positive tab assembly and a negative tab assembly; The positive electrode tab assembly includes a plurality of stacked single-piece tabs, and along the axial direction of the cylindrical battery, the stacking thickness of the positive electrode tab assembly is: 0.2mm~3.5mm; and / or, the negative electrode tab assembly includes a plurality of stacked single-piece tabs, and along the axial direction of the cylindrical battery, the stacking thickness of the negative electrode tab assembly is: 0.2mm~3.5mm.

22. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The battery cell (200) comprises a tab assembly, wherein the tab assembly comprises a positive tab assembly and a negative tab assembly; The lead-out dimension of the positive electrode tab assembly is 3 mm to 10 mm; and / or the lead-out dimension of the negative electrode tab assembly is 3 mm to 10 mm.

23. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The battery core (200) has a winding hole (201), and the diameter of the winding hole (201) ranges from 4 mm to 10 mm.

24. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The compaction density of the positive electrode sheet ranges from 2.3 g / cm³ to 3.8 g / cm³.

25. The cylindrical battery according to any one of claims 1 to 18, characterized in that: A pole (121) is provided on at least one of the end surface housing parts (120) of the battery housing (100); An explosion-proof valve is provided on the battery housing (100); the explosion-proof valve and the pole (121) are located on the same end surface housing portion (120); and the residual thickness of the explosion-proof valve ranges from 0.04 mm to 0.3 mm.

26. The cylindrical battery according to any one of claims 1 to 18, wherein: A pole (121) is provided on one of the end surface housing parts (120) of the battery housing (100); An explosion-proof valve is provided on the battery housing (100); the explosion-proof valve and the pole (121) are located on different end surface housing parts (120); and the residual thickness of the explosion-proof valve ranges from 0.04 mm to 0.35 mm.

27. The cylindrical battery according to any one of claims 1 to 18, characterized in that: The positive electrode material includes a positive electrode active material, and the positive electrode active material includes at least one of lithium iron phosphate, lithium iron manganese phosphate, ternary NCA, and ternary NCM.

28. The cylindrical battery according to claim 27, wherein: When the positive electrode active material includes lithium iron phosphate, the value range of s is 800-2200.

29. The cylindrical battery according to claim 28, wherein: The average particle size D50 of the positive electrode active material is 0.5 μm to 2 μm.

30. The cylindrical battery according to claim 27, wherein: When the positive electrode active material includes a ternary NCM, the value range of s is: 1200 mm²~2500 mm².

31. The cylindrical battery according to claim 30, wherein: The average particle size D50 of the positive electrode active material is 2 μm to 20 μm.

32. A battery pack, characterized in that: The method comprises the cylindrical battery according to any one of claims 1 to 31, wherein the number of the cylindrical batteries is 4 to 16.

33. An electrical device, characterized in that: Comprising a battery pack as described in claim 32.

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