Battery cell, battery device and power-consuming device

Abstract

A battery cell characterized in that it comprises: an electrode arrangement and an electrolyte solution; a housing body and a top cover arrangement, wherein a receiving chamber with an opening is formed in the housing body, wherein the electrode arrangement and the electrolyte solution are received in the receiving chamber, the top cover arrangement covers the opening of the housing body and a safety valve is arranged on the top cover arrangement, wherein the top cover arrangement comprises a top cover on which the safety valve is mounted, wherein a lower plastic part is arranged on a side of the top cover facing the housing body, wherein several vent holes are arranged in the area where the lower plastic part is opposite the safety valve, and the lower plastic part comprises a plastic part body and a projection arranged in the middle of the plastic part body.wherein the projection is arranged opposite the safety valve and has an air chamber connected to the multiple vent holes, and the convex surface of the projection is away from the safety valve, wherein the electrolyte solution comprises dimethyl carbonate and a lithium salt containing fluorine and sulfonic acid groups, wherein the mass fraction of the dimethyl carbonate is 16% to 30% and the mass fraction of the lithium salt containing fluorine and sulfonic acid groups is 2% to 6%, wherein the ratio of the area of ​​the safety valve to the capacity of the battery cell is 1.0 mm² / Ah to 1.5 mm² / Ah.

Description

Technical field The present application belongs to the technical field of battery technology and relates in particular to a battery cell, a battery device and a power-consuming device. State of the art With the rapid development of new energy vehicles, battery drive systems have become a crucial factor influencing both the performance and cost of these vehicles. Secondary batteries are the preferred power supply solution for battery drive systems due to their high energy density, low memory effect, and high operating voltage. Energy efficiency and operational reliability are two extremely important performance indicators for secondary batteries. However, secondary batteries that use electrolyte solution often contain additives to improve the conductivity of the electrolyte solution and thus increase kinetic performance, while simultaneously introducing the potential risk of thermal runaway. Therefore, ensuring both energy efficiency and operational reliability in batteries is challenging. Disclosure of the invention The purpose of the present application is to provide a battery cell, a battery device and a power-consuming device in order to solve the technical problem of how the battery cell can simultaneously achieve favorable energy efficiency and good operational safety. To enable the aforementioned objective of the present application, the following technical solutions are employed in the present application: In a first aspect, the present application provides a battery cell comprising: an electrode arrangement and an electrolyte solution; a housing body and a top cover arrangement, wherein a receiving chamber with an opening is formed in the housing body, wherein the electrode arrangement and the electrolyte solution are received in the receiving chamber, the top cover arrangement covers the opening of the housing body and a safety valve is arranged on the top cover arrangement, wherein the top cover arrangement comprises a top cover on which the safety valve is mounted, wherein a lower plastic part is arranged on a side of the top cover facing the housing body, wherein in the area where the lower plastic part is opposite the safety valve,The lower plastic part comprises a plastic body and a projection located in the center of the plastic body, the projection being opposite the safety valve and having an air chamber connected to the multiple vent holes, with the convex surface of the projection facing away from the safety valve. The electrolyte solution comprises dimethyl carbonate and a lithium salt containing fluorine and sulfonic acid groups, the mass fraction of dimethyl carbonate being 16% to 30% and the mass fraction of the lithium salt containing fluorine and sulfonic acid groups being 2% to 6%. The ratio of the safety valve area to the battery cell capacity is 1.0 mm² / Ah to 1.5 mm² / Ah. The safety valve may, in particular, include a pressure relief valve. A specific amount of dimethyl carbonate and a lithium salt containing fluorine and sulfonic acid groups is added to the electrolyte solution of the battery cell of the present application. In particular, the synergistic effect of the 16% to 30% dimethyl carbonate and the 2% to 6% lithium salt containing fluorine and sulfonic acid groups allows the electrolyte solution to exhibit not only lower viscosity but also improved conductivity, thereby significantly improving the kinetic performance of the battery and increasing its energy efficiency. Furthermore, the aforementioned proportions of dimethyl carbonate and lithium salt containing fluorine and sulfonic acid groups minimize gas evolution and heat generation in the electrolyte solution, thus considerably reducing the risk of thermal runaway.Simultaneously, this, in combination with the safety valve provided in the top cover assembly of the battery, with an area per unit capacity of 1.0 mm² / Ah to 1.5 mm² / Ah, ensures that the outer packaging of the battery cell exhibits excellent structural strength as well as pressure relief and heat dissipation functions. This further reduces the risk of thermal runaway of the battery cell. Due to the aforementioned materials and the structural configuration, the battery cell of the present application therefore exhibits both excellent energy efficiency and high operational reliability. In some embodiments, the area of ​​the safety valve is 780 mm2 to 950 mm2. The safety valve with the aforementioned surface area can be easily attached to the top cover of the battery cell without significantly affecting its structural integrity. It allows for rapid pressure relief and heat dissipation, thus reducing the risk of thermal runaway within the battery cell caused by rapid heat accumulation. In some embodiments, the capacity of the battery cell is 520 Ah to 950 Ah. The battery cell with the aforementioned capacity is easy to manufacture and can effectively meet market demand. In some embodiments, the mass fraction of dimethyl carbonate in the electrolyte solution is 20% to 26% and the mass fraction of the lithium salt containing fluorine and sulfonic acid groups is 3% to 5%, and the ratio of the area of ​​the safety valve to the capacity of the battery cell is 1.2 mm² / Ah to 1.4 mm² / Ah. By combining the above-mentioned mass ratio of dimethyl carbonate and fluorinated lithium salt with the area per unit capacity of the safety valve, the battery cell can achieve a better balance between energy efficiency and operational safety. In some embodiments, the lithium salt containing fluorine and sulfonic acid groups comprises at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethyl sulfinate. The lithium ions in the aforementioned lithium salt containing fluorine and sulfonic acid groups dissociate easily, giving the electrolyte solution excellent ion transport properties and thus improving the electrical performance of the battery. In some embodiments, the top cover arrangement comprises a top cover to which the safety valve is attached, wherein a lower plastic part is arranged on a side of the top cover facing the housing body, and wherein several vent holes are arranged in the area where the lower plastic part is opposite the safety valve. By arranging the lower plastic part with the multiple vent holes on the side of the top cover's safety valve facing the housing body, the heat generated by the battery cell can flow through these vent holes to the safety valve, thus enabling rapid pressure relief and dissipation. In some embodiments, the total surface area of ​​the multiple vent holes is 1000 mm² to 1200 mm², and / or the shape of the multiple vent holes comprises at least one of the following shapes: circular, oval, track-shaped and polygonal. The vent holes are positioned on the lower plastic part with the aforementioned total hole area to provide improved pressure relief and thereby reduce the risk of physical rupture of the battery casing. Simultaneously, this design allows for rapid pressure release to dissipate heat from the interior of the battery cell, thus mitigating the propagation of the thermal runaway chain reaction and reducing the risk of thermal runaway. The aforementioned hole shape is easily manufactured on the lower plastic part and allows for precise control of the vent area. In some embodiments, the lower plastic part comprises a plastic part body and a projection located in the center of the plastic part body, the projection being positioned opposite the safety valve and having an air chamber connected to the multiple vent holes, and the convex surface of the projection being away from the safety valve. By arranging the projection with the air chamber connected to the vent holes, the lower plastic part forms a directed vent channel, creating a flow-guiding cavity. This allows high-temperature gases to be expelled in a concentrated manner along a predetermined path, reducing the risk of disordered diffusion and thermal spread. Simultaneously, this structure also acts as a physical barrier, mitigating the risk of solids ejected from the safety valve during pressure relief clogging the vent holes. Consequently, the likelihood of a temperature and pressure increase and an explosion is reduced. In some embodiments, the projection consists of a first projection body and a second projection body arranged parallel to each other, wherein the first projection body has a first air chamber, the second projection body has a second air chamber, the first projection body and the second projection body are arranged opposite each other along the vertical centerline of the safety valve and have symmetrical steps, and the distance between the first projection body and the second projection body is 1 mm to 4 mm. The protrusion consists of a first protrusion body and a second protrusion body, which are symmetrical to each other and each contain an air chamber. This symmetrical arrangement along the center of the safety valve forms a venting channel. High-temperature and high-pressure gas flows enter the air chamber through the vent holes, flow to the safety valve, and are discharged from the safety valve. This allows for a more uniform flow pattern. At the same time, the stepped protrusion resists collapse, thus ensuring a more stable physical structure and extending the venting effect. In some embodiments, the multiple vent holes comprise a first vent hole, a second vent hole, and a third vent hole, wherein the first vent holes are arranged symmetrically on the convex surfaces of the first and second projecting bodies, the second vent holes are arranged symmetrically on the inclined surfaces between the convex surfaces and the stepped surfaces of the first and second projecting bodies, respectively, and the third vent holes are arranged symmetrically on the stepped surfaces of the first and second projecting bodies. The symmetrical arrangement of the aforementioned first, second, and third vent holes at three symmetrical positions on the first and second projecting bodies (corresponding to their respective convex surfaces, sloping surfaces, and stepped surfaces) allows the high-temperature gases directed along the symmetrical positions of the projection to be concentrated and expelled through these three types of symmetrical vent holes, enabling them to flow efficiently to the safety valve for pressure relief and release. In some embodiments, several of the first ventilation holes are arranged symmetrically on the convex surfaces of the first projection body and the second projection body, wherein the area of ​​each of the first ventilation holes is 40 mm² to 50 mm² and the distance between two adjacent first ventilation holes of the same projection body is 2.5 mm to 4 mm; and / or on the inclined surfaces between the convex surfaces and the stepped surfaces of the first projection body or the second projection body.Several second ventilation holes are arranged symmetrically on each of the second projecting body, wherein the area of ​​each of the second ventilation holes is 14 mm² to 22 mm² and the distance between two adjacent second ventilation holes of the same projecting body is 2.5 mm to 4 mm; and / or several third ventilation holes are arranged symmetrically on the stepped surfaces of the first and second projecting body, wherein the area of ​​each of the third ventilation holes is 10 mm² to 14 mm² and the distance between two adjacent third ventilation holes of the same projecting body is 1 mm to 3 mm. By arranging the first, second, and third vent holes in the specified quantities and dimensions, the overall impact on the mechanical structural strength of the lower plastic part is minimized. Simultaneously, any hot gas that may form inside the battery can be evenly discharged towards the safety valve. A control mechanism reduces the speed and intensity of the expelled gas, ensuring stable pressure relief at the safety valve. In a second aspect, the present application provides a battery device comprising a battery cell provided in the first aspect of the present application. The battery cell specific to the embodiments of the present application is used in the battery device. Due to the property that the battery cell can simultaneously ensure high energy density and good operational reliability, the battery device of the present application can store or provide electrical energy very efficiently. In a third aspect, the present application provides a power-consuming device comprising either the battery cell of the first aspect of the present application or the battery device of the second aspect of the present application, wherein the battery cell or the battery device serves to store or provide electrical energy. The power-consuming device comprises a battery cell or a battery device specific to the embodiments of the present application. Consequently, the power-consuming device of the present application can simultaneously ensure both energy density and operational reliability, which allows it to function very well. The foregoing description merely provides an overview of the technical solutions of the present application. To facilitate a clearer understanding of the technical means employed herein, to make implementation in accordance with the description easier, and to more clearly highlight the aforementioned and other objectives, features, and advantages of the present application, specific embodiments of the present application are hereby provided. Brief description of the drawings Based on the following detailed description of the preferred embodiments, a person skilled in the art will recognize various further advantages and benefits. The drawings serve solely to illustrate the preferred embodiments and are not to be construed as limiting the present application. Furthermore, the same reference numerals are used in all drawings to represent identical parts. In the drawings: Fig. 1 is a schematic representation of the structure of a battery cell according to the embodiments of the present application; Fig. 2 is a schematic exploded view of the battery cell shown in Fig. 1; Fig. 3 is a cross-section of a top cover arrangement in the battery cell according to the embodiments of the present application; Fig.Figure 4 is a bottom view of a lower plastic part of the battery cell according to the embodiments of the present application, looking from a housing body to the top cover arrangement; Figure 5 is a schematic representation of the structure of an embodiment of the battery module according to the embodiments of the present application; Figure 6 is a schematic exploded view of the structure of a battery pack according to the embodiments of the present application; Figure 7 is a schematic representation of an embodiment of the power-consuming device, which includes a secondary battery according to the embodiments of the present application as a power source. Detailed descriptions The following are detailed descriptions of the embodiments of the technical solutions of the present application with reference to the drawings. These embodiments serve only to illustrate the technical solutions of the present application and are therefore to be understood merely as examples that do not limit the scope of protection of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by a person skilled in the art; the terms used herein are only for the purpose of describing certain embodiments and are not intended to limit this application; the terms "comprise" and "comprising" and all variations thereof, as used in the description and claims of this application and in the preceding description of the drawings, are intended to cover non-exclusive embodiments. In the description of embodiments of this application, technical terms such as "first" and "second", etc., are used solely to distinguish between different objects and should not be interpreted as indicating or suggesting a relative meaning, nor as implicitly specifying the quantity, particular order, or hierarchical relationship of the technical features mentioned. In the description of embodiments of this application, "several" means more than two, unless expressly defined otherwise. A reference to "embodiment" in this document means that certain features, structures, or properties described in connection with an embodiment may be included in at least one embodiment of the present application. The appearance of the preceding phrase at various points in the description does not necessarily mean that it refers to the same embodiment, nor does it represent an independent or alternative embodiment that is mutually exclusive with other embodiments. The person skilled in the art expressly and implicitly understands that the embodiments described herein may be combined with other embodiments. In the description of the embodiments of this application, the term "and / or" serves only to describe an associative relationship between the associated objects, indicating that three types of relationships can exist, such as A and / or B, which can represent the following three scenarios: A alone, both A and B, and B alone. Furthermore, the symbol " / " in this document generally represents an "or" relationship between the leading and trailing associated objects. In the description of embodiments of the present application, the term "several" refers to two or more (including two), likewise "several sentences" refers to two or more sentences (including two sentences) and "several sheets" refers to two or more sheets (including two sheets). "At least one" refers to one or more (including one, two, three, etc.). In the description of the embodiments of this application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "top", "bottom", "front", "back", "left", "right", "vertical", "at the very top", "at the very bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., are based on the orientation or positional relationships shown in the drawings. These terms serve solely to facilitate and simplify the description of the embodiments of this application and are not intended to indicate or imply that the devices or elements mentioned must necessarily have a particular orientation, be constructed in a particular orientation, or be operated in a particular orientation. Therefore, they should not be interpreted as limitations on the embodiments of this application. In the description of the embodiments of this application, the technical terms "install," "connect," "couple," and "fasten" should be understood broadly unless expressly stated and defined otherwise. For example, it may refer to a permanent connection, a detachable connection, or a one-piece design; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection via an intermediate medium; and it may be an internal connection or an interaction relationship between two components. The person skilled in the art will be able to understand the specific meaning of the above terms in the embodiments of this application within the respective context. Given the dwindling reserves of traditional energy resources, the development of new energy storage systems is becoming increasingly important. Among these, secondary batteries have attracted considerable attention due to their high energy density, high theoretical capacity, excellent cycle stability, and environmentally friendly properties. Secondary batteries can be used not only in energy storage systems such as hydroelectric, thermal, wind, and solar power plants, but also widely in electric vehicles such as e-bikes, e-motorcycles, and electric cars. With the continuous expansion of applications for secondary batteries, which can serve as traction batteries, market demand is also steadily increasing. Lithium-ion batteries are a type of secondary battery where energy efficiency and operational safety are two crucial evaluation criteria. A battery's energy efficiency refers to the percentage of discharge energy relative to charge energy during the battery's charge-discharge cycle and serves as a key metric for assessing battery performance. The formula is: (Discharge energy / Charge energy) × 100%. Thermal runaway is the primary cause of safety incidents in lithium-ion batteries, with factors such as overcharging, internal short circuits, or high external temperatures potentially triggering intense exothermic chain reactions within the battery. When the battery temperature exceeds a certain threshold, the rate of heat generation increases exponentially, far exceeding the rate of heat dissipation.For example, the casing of certain batteries can burst at temperatures above 150 °C, which in turn leads to burns and explosions and significantly compromises safety in application scenarios such as electric vehicles. Preventing thermal runaway requires multi-stage coordination. Currently, certain additives and lithium salts are typically added to the electrolyte solution to improve battery cell kinetics and increase energy efficiency. However, the addition of certain strongly oxidizing substances can easily lead to violent reduction reactions with the fully charged negative electrode when the battery is fully charged. This releases significant amounts of heat, leading to thermal runaway and compromising operational safety. Therefore, ensuring both energy efficiency and safety simultaneously is challenging. Based on this, a battery cell is developed in the embodiments of the present application. By adding a specific mass ratio of dimethyl carbonate and lithium salt containing fluorine and sulfonic acid groups to the electrolyte solution, and by simultaneously incorporating a safety valve with a specific area, the battery cell of the present application achieves both excellent energy efficiency and outstanding operational reliability due to the aforementioned combination of materials and structures. The specific technical solutions are as follows. [Battery cell] The battery cell of the embodiments of the present application comprises a battery housing body, an electrode arrangement, and an electrolyte solution encapsulated within the battery housing body. The shape of the battery cell is not subject to any particular restrictions; it can be cylindrical, rectangular, or any other shape. As shown in Fig. 1, the battery cell 10 has a square structure. The positive electrode sheet, the separator, and the negative electrode sheet contained in the battery cell of the embodiments of the present application can be formed into an electrode arrangement by a winding process and / or a stacking process. The electrode arrangement is encapsulated in the receiving chamber, with the electrolyte solution wetting the electrode arrangement.The number of electrode arrangements contained in battery cell 10 can be one or more and can be adjusted according to actual requirements. In some embodiments, and as shown in Figures 2, 3 to 4, the outer packaging of the battery cell 10 can comprise a housing body 11 and a top cover assembly 12. The housing body 11 has a receiving chamber with an opening, the receiving chamber containing the electrode assembly 13 and the electrolyte solution. The housing body 11 has an opening that communicates with the receiving chamber, and the top cover assembly 12 serves to cover the opening and close the receiving chamber. A safety valve 121 is arranged on the top cover assembly 12, the ratio of the area of ​​the safety valve 121 to the capacity of the battery cell 10 being 1.0 mm² / Ah to 1.5 mm² / Ah. In particular, the ratio of the area of ​​the safety valve 121 to the capacity of the battery cell 10 can be one of the following point values: 1.0 mm2 / Ah, 1.1 mm2 / Ah, 1.2 mm2 / Ah, 1.3 mm2 / Ah, 1.4 mm2 / Ah, 1.5 mm2 / Ah, etc., or lie within a range formed by two of these point values. The electrolyte solution comprises dimethyl carbonate (DMC) and a lithium salt containing fluorine and sulfonic acid groups, wherein the mass fraction of dimethyl carbonate in the electrolyte solution is 16% to 30% and the mass fraction of the lithium salt containing fluorine and sulfonic acid groups in the electrolyte solution is 2% to 6%. Specifically, the mass fraction of dimethyl carbonate may be one of the following values: 16%, 17%, 18%, 19%, 20%, 22%, 23%, 24%, 25%, 28%, 29%, 30%, etc., or within a range formed by any two of these values. The mass fraction of the lithium salt containing fluorine and sulfonic acid groups may be one of the following values: 2%, 3%, 4%, 5%, 6%, etc., or within a range formed by any two of these values. Dimethyl carbonate can reduce the viscosity of the electrolyte solution but exhibits poor thermal stability, while the lithium ions of the fluorine- and sulfonic acid-containing lithium salt dissociate readily but generally have disadvantages such as strong oxidizing properties. For the battery cell to achieve both excellent energy efficiency and high operational reliability, the simultaneous addition of both compounds to the electrolyte solution presents a challenge in terms of dosage control. The embodiments of the present application are intended to ensure that both the dimethyl carbonate and the lithium salt containing fluorine and sulfonic acid groups synergistically reduce the viscosity of the electrolyte solution, improve the ionic conductivity of the electrolyte solution, and lower the potential barrier of lithium ion transport, thereby improving the kinetics of the battery cell and increasing its energy efficiency, but also minimize the release of significant heat from the battery cell and thus reduce the risk of thermal runaway. The present application has demonstrated through experiments that the addition of 16% to 30% dimethyl carbonate and 2% to 6% lithium salt containing fluorine and sulfonic acid groups to the electrolyte solution of the battery cell can, on the one hand, significantly improve the energy efficiency of the battery cell 10 and, on the other hand, reduce the risk of thermal runaway of the battery cell 10.Simultaneously, based on this, in combination with the safety valve 121 provided in the top cover arrangement 12 of the battery cell 10, with an area per unit capacity of 1.0 mm² / Ah to 1.5 mm² / Ah, the outer packaging of the battery cell 10 achieves excellent structural strength as well as pressure relief and heat dissipation functions. This further reduces the risk of thermal runaway of the battery cell. Due to the aforementioned materials and the structural configuration in the embodiments of the present application, the battery cell 10 of the embodiments of the present application therefore exhibits both excellent energy efficiency and high operational reliability. The safety valve 121 is a battery safety device that prevents the battery from easily exploding under abnormal conditions. It is an important battery component capable of automatically opening the valve to release internal pressure if the pressure inside the battery becomes too high. The ratio of the safety valve 121's area to the battery cell 10's capacity is the ratio of the projected area S of the safety valve 121 in the vertical direction of the battery cell 10 to the battery cell's capacity C. The following applies: 1.0 mm² / Ah ≤ S / C ≤ 1.5 mm² / Ah. The combination of the aforementioned electrolyte solution with the appropriate safety valve 121 per unit area enables excellent pressure relief and rapid heat dissipation, further reducing the risk of thermal runaway in the battery cell 10. In some embodiments, the lithium salt containing fluorine and sulfonic acid groups in the electrolyte solution comprises at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium trifluoromethyl sulfinate. The lithium ions in these fluorine and sulfonic acid-containing lithium salts dissociate readily, which allows the electrolyte solution to exhibit excellent ion transport properties and thus improves the electrical performance of the battery. By combining this with the aforementioned dimethyl carbonate and the ratio of the safety valve area to the battery cell capacity, the battery cell can achieve both excellent energy efficiency and high operational reliability. Furthermore, the electrolyte solution may also contain a major lithium salt, such as lithium hexafluorophosphate, at a concentration of 0.8 mol / L to 1.2 mol / L. The 2% to 6% fluorine- and sulfonic acid-containing lithium salt in the electrolyte solution may be lithium bis(fluorosulfonyl)imide (LiFSI), meaning that lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate are selected for the composition of the lithium salt in the electrolyte solution. In some embodiments, the area of ​​the safety valve 121 is 780 mm² to 950 mm². In particular, the area of ​​the safety valve 121 can be one of the following point values: 780 mm², 800 mm², 820 mm², 850 mm², 860 mm², 880 mm², 900 mm², 920 mm², 940 mm², 950 mm², etc., or lie within a range formed by two of these point values. The suitable surface area of ​​the safety valve 121 minimizes its impact on the structural strength of the top cover assembly 12. Simultaneously, the weld between the safety valve 121 and the top cover assembly 12 is appropriately designed, thereby reducing the probability of weld defects. In the embodiments of the present application, the safety valve 121 with the aforementioned surface area can be readily attached to the top cover assembly 12 of the battery cell 10 without significantly affecting the structural strength of the top cover. It enables rapid pressure relief and heat dissipation, thus effectively reducing the risk of thermal runaway within the battery cell 10 caused by rapid heat accumulation. In some embodiments, the capacity of battery cell 10 ranges from 520 Ah to 950 Ah. Specifically, the capacity of battery cell 10 can be one of the following values: 520 Ah, 550 Ah, 580 Ah, 600 Ah, 620 Ah, 650 Ah, 680 Ah, 700 Ah, 720 Ah, 750 Ah, 780 Ah, 800 Ah, 850 Ah, 860 Ah, 880 Ah, 900 Ah, 920 Ah, 940 Ah, 950 Ah, etc., or within a range defined by any two of these values. A battery cell with the aforementioned capacity is easy to manufacture and can effectively meet market demand. In some embodiments, the mass fraction of dimethyl carbonate in the electrolyte solution is 20% to 26%, and the mass fraction of the fluorinated lithium salt (such as lithium bis(fluorosulfonyl)imide) is 3% to 5%, and the ratio of the area of ​​the safety valve 121 to the capacity of the battery cell 10 is 1.2 mm² / Ah to 1.4 mm² / Ah. By further selecting the combination of the aforementioned mass ratio of dimethyl carbonate and lithium bis(fluorosulfonyl)imide with the aforementioned area per unit capacity of the safety valve, the battery cell can achieve a better balance between energy efficiency and operational safety. In some embodiments, the top cover arrangement 12 comprises a top cover 120 to which the safety valve 121 is attached, wherein a lower plastic part 122 is arranged on a side of the top cover 120 facing the housing body 11, wherein several vent holes are arranged in the area where the lower plastic part 122 is opposite the safety valve 121. After the safety valve 121 opens for pressure relief, the high-temperature and high-pressure gas flow generated by thermal runaway in battery cell 10 concentrates mainly in the area of ​​the safety valve 121. Several vent holes are arranged in the area where the lower plastic part 122 faces the safety valve 121. These vent holes connect the interior of the battery to the safety valve 121. This allows the heat generated in battery cell 10 to flow through these vent holes to the safety valve 121, enabling rapid pressure relief and dissipation via the safety valve 121. In some embodiments, the total area of ​​the multiple vent holes in the lower plastic part 122 is between 1000 mm² and 1200 mm². Specifically, the total area of ​​the multiple vent holes is one of the following values: 1000 mm², 1020 mm², 1050 mm², 1080 mm², 1100 mm², 1120 mm², 1140 mm², 1150 mm², 1160 mm², 1180 mm², 1200 mm², etc., or lies within a range defined by any two of these values. The total area refers to the sum of the areas of all vent holes arranged on the lower plastic part 122. The vent holes are arranged on the lower plastic part 122 with the aforementioned total area to provide improved pressure relief and thereby reduce the risk of physical breakage of the battery housing body.At the same time, this design allows for rapid pressure relief to dissipate heat from the interior of battery cell 10, thereby mitigating the propagation of the chain reaction of thermal runaway and reducing the risk of thermal runaway. In some embodiments, the shape of the multiple vent holes in the lower plastic part 122 comprises at least one of the following shapes: circular, oval, track-shaped, and polygonal. The aforementioned hole shape is easy to produce in the lower plastic part and allows for precise control of the venting area of ​​the vent holes. In some embodiments, the lower plastic part 122 comprises a plastic body and a projection located in the center of the plastic body. The projection is positioned opposite the safety valve 121 and has an air chamber connected to the multiple vent holes. The convex surface of the projection faces away from the safety valve 121. The projection thus extends away from the safety valve 121 in one direction: towards the electrode assembly 13 within the battery cell 10. The projecting projection can form an air chamber connected to the multiple vent holes. This projection allows the lower plastic part 122 to form a directed vent channel, thereby creating a flow-conducting cavity.This allows high-temperature gases to be expelled in a concentrated manner along a predetermined path, thereby reducing the risk of disordered diffusion and thermal spread. Simultaneously, this protrusion structure can also serve as physical protection, mitigating the risk of solids expelled from safety valve 121 during pressure relief clogging the vent holes. Consequently, the probability of a temperature and pressure increase and an explosion is reduced. In particular, in the embodiments of the present application, a large-area safety valve 121 with an area of ​​780 mm² to 950 mm² is used, starting from an electrolyte solution with a specific concentration of DMC and LiFSI. Furthermore, a directed venting channel is formed by means of the projection of the lower plastic part 122. This achieves directed pressure relief and rapid heat dissipation, reduces thermal spread, and thus significantly improves battery safety. In some embodiments, the projection consists of a first projection body and a second projection body arranged parallel to each other, each having an air chamber connected to the vent holes. That is, the first projection body has a first air chamber, while the second projection body has a second air chamber. The first and second projection bodies are arranged opposite each other along the vertical centerline of the safety valve 121 and have symmetrical steps, with the distance t between the first and second projection bodies being 1 mm to 4 mm. The lower plastic part 122 has a projection structure directly below the safety valve 121.The projection of the lower plastic part 122 consists of a first projection body and a second projection body, which are symmetrical to each other and each have an air chamber. This symmetrical arrangement along the center of the safety valve forms a venting channel. High-temperature and high-pressure gas flows enter the air chamber through the vent holes, flow to the safety valve, and are discharged from the safety valve. This allows for a more uniform flow. At the same time, the stepped projection resists collapse, thus ensuring a more stable physical structure and extending the venting effect. For example, the projection along the centerline of the safety valve 121 can be vertically divided into a first projection body and a second projection body, which are arranged parallel to each other. In some embodiments, the multiple vent holes of the lower plastic part 122 comprise a first vent hole 1221, a second vent hole 1222 and a third vent hole 1223, wherein the first vent holes 1221 are arranged symmetrically on the convex surfaces of the first projection body and the second projection body, the second vent holes 1222 are arranged symmetrically on the inclined surfaces between the convex surfaces and the stepped surfaces of the first projection body and the second projection body, respectively, and the third vent holes 1223 are arranged symmetrically on the stepped surfaces of the first projection body and the second projection body. The lower plastic part 122 has a projection structure directly below the safety valve 121, consisting of the first and second projection bodies, which are symmetrical to each other. The symmetrical arrangement of the first, second, and third ventilation holes 1221, 1222, and 1223 at three positions on the first and second projection bodies—namely, in the areas of the convex surfaces, the inclined surfaces, and the stepped surfaces—allows the high-temperature gases flowing along the projection to be concentrated and expelled through these three types of symmetrical ventilation holes, thus enabling them to flow efficiently to the safety valve 121 for pressure relief and release. For example, a row of first ventilation holes 1221 is arranged on the convex surface of the first projecting body, and a row of first ventilation holes 1221 is arranged on the convex surface of the second projecting body. These two rows of first ventilation holes 1221 are arranged symmetrically, i.e., they are identical in size, shape, and spacing. A row of second ventilation holes 1222 is arranged on the inclined surface of the first projecting body, and a row of second ventilation holes 1222 is arranged on the inclined surface of the second projecting body. These two rows of second ventilation holes 1222 are also arranged symmetrically, i.e., they are identical in size, shape, and spacing. A row of third ventilation holes 1223 is arranged in the stepped surface of the first projecting body, and a row of third ventilation holes 1223 is arranged in the stepped surface of the second projecting body.These two rows of the third ventilation holes 1223 are arranged symmetrically, i.e., they are identical in size, shape, and spacing. The high-temperature gases generated inside the battery cell 10 are expelled through these three types of symmetrical ventilation holes, allowing them to flow efficiently to the safety valve 121 for pressure relief and release. In some embodiments, a transfer plate for the electrode is further arranged on the top cover assembly 12 for connecting an electrode blade to an electrode tab of the electrode assembly 13, which in particular comprises a transfer plate 1231 for the negative electrode and a transfer plate 1232 for the positive electrode. An electrolyte filling hole 124 for filling the battery cell 10 with the electrolyte solution is also arranged on the top cover assembly 12. The shape of the multiple vent holes includes at least one of the following forms: circular, oval, track-shaped, and polygonal. Of these, the track-shaped form refers to a hole shape resembling a racetrack, while the polygon can be either irregular or regular. For reasons of manufacturability and ease of controlling the hole area, the polygon can be a regular polygon such as an equilateral triangle, a square, a rectangle, etc. The aforementioned vent holes can be evenly distributed in the lateral direction of the battery cell 10 on the lower plastic part 122. To ensure manufacturability and facilitate control of the opening area, the shape of all vent holes is circular.In some embodiments, to improve ventilation efficiency, the first ventilation hole 1221 can be track-shaped, the second ventilation hole 1222 oval, and the third ventilation hole 1223 circular. In some embodiments, several of the first ventilation holes 1221 are arranged symmetrically on the convex surfaces of the first and second projecting bodies, the area of ​​each of the first ventilation holes 1221 being 40 mm² to 50 mm² and the distance between two adjacent first ventilation holes 1221 of the same projecting body being 2.5 mm to 4 mm. That is, the area of ​​each of the first ventilation holes 1221 arranged on the convex surface of the first projecting body is 40 mm² to 50 mm², and the distance between two adjacent first ventilation holes 1221 is 2.5 mm to 4 mm. The area of ​​each of the first ventilation holes 1221 arranged on the convex surface of the second projecting body is 40 mm² to 50 mm², and the distance between two adjacent first ventilation holes 1221 is 2.5 mm to 4 mm.Furthermore, the first ventilation holes 1221 on the first projection body and the first ventilation holes 1221 on the second projection body are arranged symmetrically. In some embodiments, several of the second ventilation holes 1222 are arranged symmetrically on the inclined surfaces between the convex surfaces and the stepped surfaces of the first projection body and the second projection body, respectively, wherein the area of ​​each of the second ventilation holes 1222 is 14 mm² to 22 mm² and the distance between two adjacent second ventilation holes 1222 of the same projection body is 2.5 mm to 4 mm. That is, the area of ​​each of the second ventilation holes 1222 that is arranged on the inclined surface between the convex surface and the stepped surface of the first projection body is 14 mm² to 22 mm², and the distance between two adjacent second ventilation holes 1222 is 2.5 mm to 4 mm.The area of ​​each of the second ventilation holes 1222, which is arranged on the inclined surface between the convex surface and the stepped surface of the second projection body, is 14 mm² to 22 mm², and the distance between two adjacent second ventilation holes 1222 is 2.5 mm to 4 mm. Furthermore, the second ventilation holes 1222 on the first projection body and the second ventilation holes 1222 on the second projection body are arranged symmetrically. In some embodiments, several of the third ventilation holes 1223 are arranged symmetrically on the stepped surfaces of the first and second projecting bodies, the area of ​​the third ventilation holes 1223 being 10 mm² to 14 mm² and the distance between two adjacent third ventilation holes 1223 of the same projecting body being 1 mm to 3 mm. That is, the area of ​​each of the third ventilation holes 1223 arranged on the stepped surface of the first projecting body is 10 mm² to 14 mm², and the distance between two adjacent third ventilation holes 1223 is 1 mm to 3 mm. The area of ​​each of the third ventilation holes 1223 arranged on the stepped surface of the second projecting body is 10 mm² to 14 mm², and the distance between two adjacent third ventilation holes 1223 is 1 mm to 3 mm.Furthermore, the third ventilation holes 1223 on the first projection body and the third ventilation holes 1223 on the second projection body are arranged symmetrically. The stepped surfaces of the first and second projection bodies can be small arcuate platforms corresponding to the arcuate positions on both sides of the safety valve 121. It should be noted that the distance between the aforementioned ventilation holes refers to the shortest distance between two points on the respective edge of two adjacent ventilation holes. By arranging the first ventilation holes 1221, the second ventilation holes 1222, and the third ventilation holes 1223 in the specified quantities and dimensions, the overall impact on the mechanical structural strength of the lower plastic part is minimized. At the same time, any hot gas that may form inside the battery can be evenly discharged towards the safety valve. A control system reduces the speed and intensity of the expelled gas, ensuring stable pressure relief at the safety valve. The electrolyte solution comprises an organic solvent, which may further comprise one or more chain carbonates, cyclic carbonates, and carboxylic acid esters. There are no particular restrictions regarding the types of chain carbonates, cyclic carbonates, or carboxylic acid esters; these may be selected according to practical requirements. The organic solvent may further comprise one or more of the following: diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, methyl formate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and tetrahydrofuran. In some embodiments, the electrolyte solution optionally includes an additive. For example, the additive may include a negative electrode film-forming additive, a positive electrode film-forming additive, and an additive that can improve certain battery performance characteristics, such as an additive that improves the battery's overcharge behavior, an additive that improves the battery's high-temperature performance, and an additive that improves the battery's low-temperature performance. For example, in addition to lithium salt containing fluorine and sulfonic acid groups (such as lithium bis(fluorosulfonyl)imide), the electrolyte solution may contain further additives selected from at least one of the following: cyclic carbonate compounds with unsaturated bonds, halogen-substituted cyclic carbonate compounds, sulfate ester compounds, sulfite ester compounds, sulfonic acid-containing lactone compounds, disulfonic acid compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphonitrile compounds, cyclic anhydride compounds, hypophosphite compounds, phosphate ester compounds, borate ester compounds, and carboxylic acid ester compounds. The embodiments of the present application provide a battery cell. The battery cell of the embodiments of the present application comprises a negative electrode sheet. The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector. The negative electrode film layer contains a negative electrode active material. By way of example, the negative electrode active material can be a negative electrode active material known in the art for the battery cell. By way of example, the negative electrode active material can comprise at least one of synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.The silicon-based material can be selected from at least one of elemental silicon, silicon oxide compound, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material can be selected from at least one of elemental tin, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials suitable for use as negative electrode active materials for a battery may also be used. These negative electrode active materials may be used alone or in combination with one or more of them. In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector can comprise a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on the polymer material substrate, such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc. In some embodiments, the negative electrode film layer of the negative electrode sheet optionally comprises a conductive agent and a binder. The binder can be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). The conductive agent can be selected from at least one of superconducting carbon, carbon black, carbon black, Ketjen carbon black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the composition, based on the total weight of the negative electrode film layer of 100%, comprises the following weight percentages: negative electrode active material: 92% to 99%, conductive agent: 0.5% to 4%, and binder: 0.5% to 4%. In some embodiments, the battery cell comprises a positive electrode sheet and a negative electrode sheet. In some embodiments, the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector. The positive electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector can comprise a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on the polymer material substrate, such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc. In some embodiments, the positive electrode film layer contains a positive electrode active substance, wherein the positive electrode film layer may contain a positive electrode active substance known in the art for a battery. For example, the positive electrode active substance of the lithium-ion secondary battery may comprise at least one lithium-containing phosphate with an olivine structure, lithium transition metal oxide, and their modified compounds. However, the present application is not limited to these materials, and other conventional materials suitable for use as a positive electrode active substance for a battery may also be used. These positive electrode active substances may be used alone or in combination with one or more of them.Examples of lithium transition metal oxides include at least one of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also known as NCM333), LiNi0,5Co0,2Mn0,3O2 (also known as NCM523), LiNi0,5Co0,25Mn0,25O2 (also known as NCM211), LiNi0,6Co0,2Mn0,2O2 (also known as NCM622), LiNi0,8Co0,1Mn0,1O2 (also known as NCM811)). lithium nickel cobalt aluminum oxide (such as LiNi0,85Co0,15Al0,05O2) and their modified compounds, but are not limited to them.Examples of lithium-containing phosphate with an olivine structure may include, but are not limited to, at least one of the following: lithium iron phosphate (such as LiFePO4), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, or lithium manganese iron phosphate and carbon composites. The weight ratio of the positive electrode active substance in the positive electrode film layer is 90 wt% to 99 wt%, based on the total weight of the positive electrode film layer. In some embodiments, the positive electrode film layer optionally comprises a binder. For example, the binder in the positive electrode film layer may comprise at least one of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. The weight ratio of the binder in the positive electrode film layer is 0.5 wt.% to 5 wt.%, based on the total weight of the positive electrode film layer. In some embodiments, the positive electrode film layer optionally comprises a conductive material. For example, the conductive material may include at least one of superconducting carbon, carbon black (e.g., acetylene carbon black or Ketjen carbon black), carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The weight ratio of the conductive material in the positive electrode film layer is 0.5 wt.% to 5 wt.%, based on the total weight of the positive electrode film layer. In embodiments of the present application, the battery cell may be a secondary battery, wherein the secondary battery is a battery cell that can continue to be used by activating the active material through charging after the discharge of the battery cell. A typical battery cell comprises a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions intercalate and deintercalate between the positive and negative electrodes. The electrolyte facilitates the flow of ions between these two electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ion permeability. In one embodiment, the separator can be made of a material known in the art for battery separators. For example, the base film of the separator can comprise one or more polyethylene films, polypropylene films, and polyvinylidene fluoride films. [Battery device] The present application provides a battery device. In particular, the battery device comprises a battery cell according to the embodiments of the present application. The battery cell specific to the embodiments of the present application is used in the battery device. Due to the advantage that the battery cell simultaneously ensures high energy density and good operational reliability, the battery device of the present application can store or provide electrical energy very efficiently. The battery apparatus mentioned in the embodiments of the present application can comprise one or more battery cell assemblies to provide voltage and capacity. The battery cell assembly can comprise several battery cells connected in series, parallel, or in a mixed configuration via a bus component. In some embodiments, a battery cell assembly is generally formed by arranging the multiple battery cells. In some embodiments, the battery device may comprise a battery cell, battery module, or battery pack. The method for manufacturing the battery cell 10 is known. In some embodiments, the positive electrode sheet, the separator, the negative electrode sheet, and the electrolyte solution can be assembled to form a battery cell 10. For example, the positive electrode sheet, the separator, and the negative electrode sheet can be formed into an electrode assembly 13 by a winding or stacking process. The electrode assembly 13 is inserted into an outer packaging. After drying, an electrolyte solution is injected, and after vacuum sealing, standing, formation, and calibration, a battery cell 10 is obtained. A battery module is composed of these battery cells 10, i.e. it can contain several such battery cells 10, the exact number of which can be adjusted depending on the application and capacity of the battery module. In some embodiments, Fig. 5 shows a schematic representation of a battery module 20 as an example. As shown in Fig. 5, several battery cells 10 can be arranged sequentially along the length of the battery module 20. Of course, other arrangements are also possible. Furthermore, the multiple battery cells 10 can be fixed by fastening elements. Optionally, the battery module 20 can also include a housing with a receiving space, in which the multiple battery cells 10 are received. A battery pack is composed of the aforementioned battery cells 10, meaning it can contain multiple battery cells 10. Several of these battery cells 10 can be combined to form the aforementioned battery module 20. The exact number of battery cells 10 or battery modules 20 contained in the battery pack can be adjusted depending on the application and capacity of the battery pack. As in the exemplary embodiments, Fig. 6 shows a schematic representation of a battery pack 30 as an example. The battery pack 30 can comprise a battery box and several battery modules 20 arranged therein. The battery box comprises an upper box body 31 and a lower box body 32; the upper box body 31 can cover the lower box body 32 and form an enclosed space for receiving the battery modules 20. The several battery modules 20 can be arranged in any way within the battery box. [Power-consuming device] The present application provides a power-consuming device. In particular, the power-consuming device comprises a battery cell according to the embodiments of the present application or a battery device according to the embodiments of the present application, wherein the battery cell or the battery device serves to store or provide electrical energy. The power-consuming device comprises a battery cell or a battery device specific to the embodiments of the present application. Consequently, the power-consuming device of the present application has a high energy density, which enables it to function better. The power-consuming device can be, but is not limited to, a mobile device (such as a mobile phone, laptop, etc.), an electric vehicle (such as a pure electric vehicle, hybrid electric vehicle, plug-in hybrid electric vehicle, electric bicycle, electric scooter, electric golf cart, electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc. This power-consuming device can be equipped with a battery cell, battery module, or battery pack, depending on its usage requirements. Fig. 7 shows a schematic representation of a power-consuming device as an example. The power-consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the power-consuming device's requirements for high power and high energy density, a battery pack or battery module can be used. Another example of a power-consuming device could be a mobile phone, tablet, laptop, etc. The power-consuming device typically needs to be lightweight and thin and can use a secondary battery as a power source. Example of implementation The following are exemplary embodiments of the present application. These embodiments are for illustrative purposes only and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the technical literature or product instructions must be followed. All reagents and instruments used without manufacturer information are commercially available products. Example 1 A battery cell comprised an electrode assembly and an electrolyte solution, the outer packaging of which consisted of a housing body and a top cover assembly. The housing body had a receiving chamber with an opening, in which the electrode assembly and the electrolyte solution were contained. The top cover assembly covered the opening of the housing body and comprised a top cover on which the safety valve was mounted. A lower plastic part was arranged on one side of the top cover facing the housing body. The lower plastic part comprised a plastic body and a projection, the projection being positioned opposite the safety valve and projecting away from the safety valve. The projection was provided with a step. An inclined surface was formed between the convex surface and the step surface of the projection.The projection consisted of a first projection body and a second projection body arranged parallel to each other. The first projection body had a first air chamber, while the second projection body had a second air chamber. The first and second projection bodies were arranged symmetrically along the vertical centerline of the safety valve and had symmetrical steps. The distance t between the first and second projection bodies was 2 mm.In the area where the lower plastic part faced the safety valve, several vent holes were arranged (connected to the air chamber): first vent holes were arranged symmetrically on the convex surfaces of the first and second projecting bodies, second vent holes were arranged symmetrically on the inclined surfaces of the first and second projecting bodies, and third vent holes were arranged symmetrically on the stepped surfaces of the first and second projecting bodies. The exact quantities and dimensions are given in Table 1. The electrolyte solution comprised dimethyl carbonate and a lithium bis(fluorosulfonyl)imide, with the mass fraction of dimethyl carbonate being 22% and the mass fraction of lithium bis(fluorosulfonyl)imide being 4%, the area of ​​the safety valve being 840 mm2 and the ratio to the capacity of the battery cell being 1.3 mm2 / Ah. The manufacturing steps for this battery cell are as follows: (1) Positive electrode sheet The positive electrode active material lithium iron phosphate, polyvinylidene fluoride, and conductive carbon black were mixed in a weight ratio of 97:2.2:0.8. This mixture was then added to the solvent N-methyl-2-pyrrolidone, stirred thoroughly, and its viscosity adjusted to form a positive electrode paste. The positive electrode paste was applied to both surfaces of the aluminum foil positive electrode current collector to form a positive electrode film. After drying, cold pressing, and cutting, the positive electrode sheet was obtained. (2) Negative electrode sheet The negative electrode active material graphite, the conductive agent Super P, the binder styrene-butadiene rubber (SBR), and the thickener sodium carboxymethylcellulose (CMC-Na) were mixed in a mass ratio of 95.5:1.0:2.0:1.5. Deionized water was then added and stirred to disperse the mixture, producing the negative electrode paste. This paste was then applied to both sides of the copper foil. After drying, compaction, cutting, and sheet forming, the negative electrode sheet was produced. (3) Separator A 7 µm polyethylene base film was used, onto which an inorganic ceramic coating and a dot-like organic polymer coating were applied on both sides, and which served as a separator. (4) Electrolyte solution In a glove compartment under an argon atmosphere (H₂O < 0.1 ppm, O₂ < 0.1 ppm), the organic solvents ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) were thoroughly mixed. Lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide were then added and dissolved in the organic solvents. The mixture was stirred thoroughly to achieve a dimethyl carbonate content of 22%, a lithium bis(fluorosulfonyl)imide content of 4%, and a lithium hexafluorophosphate concentration of 0.82 mol / L in the electrolyte solution, thus obtaining the electrolyte solution of embodiment 1. (5) Battery installation The positive electrode sheet, separator, and negative electrode sheet were stacked sequentially and then wound into an electrode assembly. One end of the positive electrode sheet, negative electrode sheet, and separator was fixed to a discharge roller, while the other end was stacked and secured to a winding shaft. A motor drove the winding shaft, winding the positive electrode sheet, negative electrode sheet, and separator. The electrode assembly was placed in the outer packaging. After drying, the electrolyte solution was injected. Vacuum sealing, settling, formation, calibration, and other steps resulted in a battery cell. Examples 2 to 11 A battery cell that differs from embodiment 1 as described in Table 1, wherein all other aspects are identical to embodiment 1. Comparison examples 1 to 5 A battery cell that differs from embodiment 1 as described in Table 1, wherein all other aspects are identical to embodiment 1. [Battery performance test] (1) Energy efficiency test: At 25 °C and normal pressure, the battery cell was charged to 3.65 V at a power of 0.25 P and left to rest for 10 minutes. It was then discharged to 2.5 V at a power of 0.25 P and left to rest for another 10 minutes. This charge-discharge cycle was repeated three times. The energy efficiency of the last two cycles was calculated, and the average value was recorded as the cell's energy efficiency at 0.25 P. (2) Thermal runaway test: The thermal runaway test was performed according to GBT 36276-2023: At 25 °C and normal pressure, the battery cell was charged at 0.33 C to 3.65 V. It was then charged at a constant current of 0.5 C while simultaneously being heated to induce thermal runaway. After thermal runaway, charging and heating were stopped, and the cell was monitored for one hour. The maximum temperature across the large surface area of ​​the battery cell, as well as whether the cell caught fire or exploded, were recorded. The results are shown in Table 1. As shown in Table 1: In comparison example 1, the mass fraction of dimethyl carbonate was 15%, which was below the range of 16% to 30%, resulting in reduced energy efficiency of the battery cell. In comparison example 2, the mass fraction of dimethyl carbonate was 32%, which was above the range of 16% to 30%, resulting in a significant increase in the maximum temperature on the back side of the battery cell during thermal runaway. In comparison example 3, the mass fraction of lithium bis(fluorosulfonyl)imide was 1%, which was below the range of 2% to 6%, resulting in reduced energy efficiency of the battery cell. In comparison example 4, the mass fraction of lithium bis(fluorosulfonyl)imide was 8%, which was above the range of 2% to 6%, resulting in a significant increase in the maximum temperature on the back side of the battery cell during thermal runaway.In contrast, the ratio of the safety valve area to the battery cell capacity in Comparative Example 5 was relatively low at 0.4 mm² / Ah. This led to a significant increase in the maximum temperature on the back of the battery cell during thermal runaway, resulting in a fire. In embodiments 1 to 12 of the present application, the mass fraction of dimethyl carbonate in the electrolyte solution ranged from 16% to 30%, the mass fraction of lithium bis(fluorosulfonyl)imide ranged from 2% to 6%, and the ratio of the safety valve area to the battery cell capacity was 1.0 mm² / Ah to 1.5 mm² / Ah, which provided the battery cell with excellent energy efficiency and outstanding operational safety.Simultaneously, optimization was pursued in the aforementioned areas with regard to the mass fraction of dimethyl carbonate, the mass fraction of lithium bis(fluorosulfonyl)imide, the ratio of the safety valve area to the battery cell capacity, and even the number and dimensions of the first, second, and third ventilation holes, as well as the total surface area of ​​the vent holes. Such refinements could further improve the energy efficiency and operational reliability of the battery cell. The foregoing description merely presents the preferred embodiments of the present application and is not intended to limit its scope. All modifications, equivalent replacements, and improvements made in the spirit and under the principles of the present application fall within the scope of protection of the present application. Reference symbol list: 10 Battery cell; 11 Housing body; 12 Top cover assembly; 120 Top cover; 121 Safety valve; 122 Lower plastic part; 1221 First vent hole; 1222 Second vent hole; 1223 Third vent hole; 1231 Negative electrode transfer plate; 1232 Positive electrode transfer plate; 124 Electrolyte filling hole; 13 Electrode assembly; 20 Battery module; 30 Battery pack; 31 Upper box body; 32 Lower box body.

Claims

Battery cell, characterized in that it comprises: an electrode arrangement and an electrolyte solution; a housing body and a top cover arrangement, wherein a receiving chamber with an opening is formed in the housing body, wherein the electrode arrangement and the electrolyte solution are received in the receiving chamber, the top cover arrangement covers the opening of the housing body and a safety valve is arranged on the top cover arrangement, wherein the top cover arrangement comprises a top cover on which the safety valve is mounted, wherein a lower plastic part is arranged on a side of the top cover facing the housing body, wherein several vent holes are arranged in the area where the lower plastic part is opposite the safety valve, and the lower plastic part comprises a plastic part body and a projection arranged in the middle of the plastic part body.wherein the projection is arranged opposite the safety valve and has an air chamber connected to the multiple vent holes, and the convex surface of the projection is away from the safety valve, wherein the electrolyte solution comprises dimethyl carbonate and a lithium salt containing fluorine and sulfonic acid groups, wherein the mass fraction of the dimethyl carbonate is 16% to 30% and the mass fraction of the lithium salt containing fluorine and sulfonic acid groups is 2% to 6%, wherein the ratio of the area of ​​the safety valve to the capacity of the battery cell is 1.0 mm² / Ah to 1.5 mm² / Ah. Battery cell according to claim 1, characterized in that the area of ​​the safety valve is 780 mm2 to 950 mm2. Battery cell according to claim 1, characterized in that the capacity of the battery cell is 520 Ah to 950 Ah. Battery cell according to claim 1, characterized in that the mass fraction of the dimethyl carbonate in the electrolyte solution is 20% to 26% and the mass fraction of the lithium salt containing fluorine and sulfonic acid groups is 3% to 5%, wherein the ratio of the area of ​​the safety valve to the capacity of the battery cell is 1.2 mm2 / Ah to 1.4 mm2 / Ah. Battery cell according to claim 1, characterized in that the lithium salt containing fluorine and sulfonic acid groups comprises at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethyl sulfinate. Battery cell according to one of claims 1 to 5, characterized in that the total area of ​​the multiple vent holes is 1000 mm2 to 1200 mm2, and / or the shape of the multiple vent holes comprises at least one of the following shapes: circular, oval, track-shaped and polygonal. Battery cell according to claim 6, characterized in that the projection consists of a first projection body and a second projection body arranged in parallel, wherein the first projection body has a first air chamber, the second projection body has a second air chamber, the first projection body and the second projection body are arranged opposite each other along the vertical center line of the safety valve and have symmetrical steps, and the distance between the first projection body and the second projection body is 1 mm to 4 mm. Battery cell according to claim 7, characterized in that the multiple vent holes comprise a first vent hole, a second vent hole and a third vent hole, wherein the first vent holes are arranged symmetrically on the convex surfaces of the first projection body and the second projection body, the second vent holes are arranged symmetrically on the inclined surfaces between the convex surfaces and the stepped surfaces of the first projection body and the second projection body, respectively, and the third vent holes are arranged symmetrically on the stepped surfaces of the first projection body and the second projection body. Battery cell according to claim 8, characterized in that several of the first ventilation holes are arranged symmetrically on the convex surfaces of the first projection body and the second projection body, wherein the area of ​​each of the first ventilation holes is 40 mm² to 50 mm² and the distance between two adjacent first ventilation holes of the same projection body is 2.5 mm to 4 mm; and / or on the inclined surfaces between the convex surfaces and the stepped surfaces of the first projection body or the second projection body.of the second projecting body several of the second ventilation holes are arranged symmetrically, wherein the area of ​​each of the second ventilation holes is 14 mm² to 22 mm² and the distance between two adjacent of the second ventilation holes of the same projecting body is 2.5 mm to 4 mm; and / or several of the third ventilation holes are arranged symmetrically on the stepped surfaces of the first projecting body and the second projecting body, wherein the area of ​​each of the third ventilation holes is 10 mm² to 14 mm² and the distance between two adjacent of the third ventilation holes of the same projecting body is 1 mm to 3 mm. Battery device characterized in that it comprises a battery cell according to one of claims 1 to 9. Electrically consuming device, characterized in that it comprises a battery cell according to one of claims 1 to 9 or a battery device according to claim 10, wherein the battery cell or the battery device serves to store or provide electrical energy.

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