Battery cell, battery, and electrical device

Abstract

A battery cell (100), a battery (200), and an electrical device (1000). The battery cell (100) comprises a battery housing (10) and an electrode assembly. The battery housing (10) comprises a first housing wall (11). An exhaust space is defined between the first housing wall (11) and the electrode assembly. A pressure relief structure (12) is provided on the first housing wall (11). The electrode assembly is disposed inside the battery housing (10). A protruding structure (13) is provided on the side of the first housing wall (11) facing the electrode assembly. In a direction from the first housing wall (11) to the electrode assembly, the protruding structure (13) is closer to the electrode assembly than the pressure relief structure (12).

Description

Battery cells, batteries and electrical devices

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 202421842069.4, filed on July 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0004] In related technologies, batteries generate high-temperature gases during operation. To prevent excessive pressure inside the battery cells, pressure relief structures are usually installed on the battery cells to reduce the internal pressure, thereby reducing the risk of thermal runaway and improving battery safety.

[0005] However, in related technologies, the gas generated during battery cell operation cannot smoothly reach the pressure relief structure. This prevents the gas inside the battery cell from being discharged in a timely manner, leading to a large accumulation of high-temperature gas inside the cell and increasing the risk of thermal runaway. Furthermore, when the internal pressure of the battery cell increases to a certain level, it can cause damage to the cell casing at locations other than the pressure relief structure, resulting in non-directional pressure relief. This increases the risk of non-directional pressure relief and lowers the battery's safety.

[0006] Therefore, how to ensure that the high-temperature gas generated during the operation of a battery cell is discharged in a timely manner, reduce the risk of non-directional pressure leakage, reduce the risk of thermal runaway, and improve battery safety is an urgent problem to be solved. Summary of the Invention

[0007] This application provides a battery cell, a battery, and an electrical device. The gas generated by the battery cell during operation can reach the pressure relief structure relatively smoothly and be discharged in a timely manner through the pressure relief structure, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0008] In a first aspect, this application provides a battery cell, comprising: a battery housing, the battery housing including a first housing wall, the first housing wall having a pressure relief structure; an electrode assembly disposed within the battery housing, the first housing wall and the electrode assembly defining an exhaust space; wherein, a protruding structure is provided on the side of the first housing wall facing the electrode assembly, and in the direction from the first housing wall to the electrode assembly, the protruding structure is closer to the electrode assembly than the pressure relief structure.

[0009] In the above technical solution, by setting a protruding structure on the inner side of the first shell wall with a pressure relief structure, the protruding structure is closer to the electrode assembly than the pressure relief structure. This protruding structure expands the space between the first shell wall and the electrode assembly, creating a larger exhaust space. Gas generated during battery cell operation can reach the vicinity of the pressure relief structure more smoothly through the exhaust space. Furthermore, because the protruding structure is closer to the electrode assembly than the pressure relief structure, the side of the pressure relief structure facing the electrode assembly is separated from the electrode assembly. This allows gas reaching the vicinity of the pressure relief structure to smoothly enter the pressure relief structure through the gap between the pressure relief structure and the electrode assembly, and then be discharged in a timely manner through the pressure relief structure. This achieves directional pressure relief, reduces the risk of non-directional pressure relief, reduces the risk of thermal runaway, and improves battery safety.

[0010] In some embodiments, the protrusion height of the protrusion structure relative to the first shell wall is h1, and the volume of the battery cell is V, wherein h1 and V satisfy: 3.563 × 10⁻⁶. -7 ≤h1 / V≤4.254×10 -6 .

[0011] In the above technical solution, the ratio of the protrusion height h1 of the protruding structure relative to the first shell wall to the volume V of the battery cell is h1 / V ≥ 3.563 × 10⁻⁶. -7 This design allows for a larger exhaust space, enabling the gas generated during battery cell operation to reach the vicinity of the pressure relief structure more smoothly. This reduces the pressure difference between the pressure relief structure and other locations within the battery casing, allowing the pressure relief structure to open promptly and release pressure more effectively, thus achieving better directional pressure relief. Furthermore, by ensuring that the ratio of the protrusion height h1 of the raised structure relative to the first casing wall to the volume V of the battery cell is h1 / V ≤ 4.254 × 10⁻⁶, the pressure relief structure can achieve a more efficient and targeted pressure relief. -6 This avoids the energy density of the battery cell being affected by an excessively large exhaust space. Thus, the ratio of the protrusion height h1 of the raised structure relative to the first shell wall to the volume V of the battery cell is set at 3.563 × 10⁻⁶. -7 ~4.254×10 -6 While achieving better directional pressure relief and reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0012] In some embodiments, the electrode assembly includes a positive electrode sheet, the positive electrode sheet including a positive electrode active material, wherein when the positive electrode active material includes an olivine-type compound, h1 and V satisfy: 3.563 × 10⁻⁶. -7 ≤h1 / V≤3.260×10 -6 .

[0013] In the above technical solution, when the positive electrode active material of the electrode assembly includes an olivine-type compound, the rate of gas generation during battery cell operation is relatively slow, and its thermal runaway behavior is relatively mild. This is achieved by setting the ratio h1 / V of the protrusion height h1 of the protrusion structure relative to the first shell wall to the volume V of the battery cell to 3.563 × 10⁻⁶. -7 ~3.260×10 -6 Based on the characteristics of battery cells containing olivine-type compound positive electrode active materials, the ratio of the protrusion height of the protrusion structure relative to the first shell wall to the volume of the battery cell can be set to be smaller. This allows battery cells containing olivine-type compound positive electrode active materials to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0014] In some embodiments, the electrode assembly includes a positive electrode sheet, the positive electrode sheet including a positive electrode active material, and when the positive electrode active material includes a layered compound, h1 and V satisfy: 7.125 × 10⁻⁶. -7 ≤h1 / V≤4.254×10 -6 .

[0015] In the above technical solution, when the positive electrode active material of the electrode assembly includes a layered compound, the rate of gas generation during battery cell operation is relatively rapid, and its thermal runaway behavior is relatively worse. This is mitigated by setting the ratio h1 / V of the protrusion height h1 of the protruding structure relative to the first shell wall to the volume V of the battery cell to 7.125 × 10⁻⁶. -7 ~4.254×10 -6 Based on the characteristics of battery cells containing layered compound positive electrode active materials, the ratio of the protrusion height of the protrusion structure relative to the first shell wall to the volume of the battery cell can be set to be larger. This allows battery cells containing layered compound positive electrode active materials to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0016] In some embodiments, the electrode assembly includes a negative electrode sheet, the negative electrode sheet including a negative electrode active material, wherein when the positive electrode active material includes a layered compound and the negative electrode active material does not contain Si, h1 and V satisfy 7.125 × 10⁻⁶. -7 ≤h1 / V≤3.973×10 -6 .

[0017] In the above technical solution, when the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material does not contain Si, the rate of gas generation during battery cell operation is relatively rapid, and its thermal runaway behavior is more severe. The energy density of the negative electrode active material without Si is relatively lower than that of the negative electrode active material containing Si, and the rate of gas generation and thermal runaway behavior during battery cell operation are relatively milder. This is achieved by setting the ratio h1 / V of the protrusion height h1 of the protruding structure relative to the first shell wall to the volume V of the battery cell to 7.125 × 10⁻⁶. -7 ~3.973×10 -6 Based on the characteristics of battery cells containing layered compound positive electrode active materials and negative electrode active materials that do not contain Si, the ratio of the protrusion height of the protrusion structure relative to the first shell wall to the volume of the battery cell can be set more reasonably. This allows battery cells containing layered compound positive electrode active materials and negative electrode active materials that do not contain Si to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0018] In some embodiments, the electrode assembly includes a negative electrode sheet, the negative electrode sheet includes a negative electrode active material, and when the positive electrode active material includes a layered compound and the negative electrode active material contains Si, h1 and V satisfy 8.529 × 10⁻⁶. -7 ≤h1 / V≤4.254×10 -6 .

[0019] In the above technical solution, when the positive electrode active material includes a layered compound and the negative electrode active material contains Si, the rate of gas generation during battery cell operation is relatively rapid, and its thermal runaway behavior is more severe. The energy density of the negative electrode active material containing Si is relatively higher than that of the negative electrode active material without Si, but the rate of gas generation and thermal runaway behavior during battery cell operation are also relatively worse. This is achieved by setting the ratio h1 / V of the protrusion height h1 of the protruding structure relative to the first shell wall to the volume V of the battery cell to 8.529 × 10⁻⁶. -7 ~4.254×10 -6 Based on the characteristics of battery cells containing layered compounds as positive electrode active materials and Si elements as negative electrode active materials, the ratio of the protrusion height of the protrusion structure relative to the first shell wall to the volume of the battery cell can be set more reasonably. This allows battery cells containing layered compounds as positive electrode active materials and Si elements as negative electrode active materials to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0020] In some embodiments, the projection of the protruding structure onto the first shell wall is a first projection, and the projection of the pressure relief structure onto the first shell wall is a second projection, wherein the distance between the first projection and the second projection is not less than 2 mm.

[0021] In the above technical solution, by ensuring that the distance between the projection of the protruding structure on the first shell wall and the projection of the pressure relief structure on the first shell wall is not less than 2mm, interference between the protruding structure and the pressure relief structure can be prevented. At the same time, the space near the pressure relief structure is larger, and the exhaust is smoother.

[0022] In some embodiments, the protruding structure is integrally formed with the first shell wall; or, the protruding structure is separately formed from the first shell wall.

[0023] In the above technical solutions, by making the protruding structure integrally formed with the first shell wall, the assembly process between the protruding structure and the first shell wall can be eliminated, improving production efficiency and making the connection between the protruding structure and the first shell wall more stable; or, by making the protruding structure and the first shell wall separately set, with the protruding structure being formed independently relative to the first shell wall and then connected and assembled to the first shell wall, the setting of the protruding structure on the first shell wall can be more flexible.

[0024] In some embodiments, the protrusion structure includes a plurality of spaced protrusions.

[0025] In the above technical solution, by setting the protruding structure as multiple spaced protrusions, the first shell wall and the electrode assembly can have uniform and stable support, and the exhaust space of each part can be more evenly distributed, so that the gas in different positions in the battery shell can reach the pressure relief structure more smoothly.

[0026] In some embodiments, the first shell wall is rectangular, and the plurality of protrusions are distributed on opposite sides of the pressure relief structure along the length of the first shell wall.

[0027] In the above technical solution, when the first shell wall is rectangular, the pressure relief structure has a long exhaust path on both sides along the length of the first shell wall. Most of the gas in other locations inside the battery casing reaches the pressure relief structure through the exhaust path on both sides along the length of the first shell wall. This results in multiple protrusions distributed on both sides of the pressure relief structure along the length of the first shell wall. This allows the exhaust space on both sides of the pressure relief structure along the length of the first shell wall to be opened up by the multiple protrusions, so that the gas in other locations inside the battery casing can reach the pressure relief structure more smoothly through the exhaust space.

[0028] In some embodiments, in the length direction of the first shell wall, a plurality of protrusions located on the same side of the pressure relief structure are divided into two groups of protrusions, each group of protrusions including at least one protrusion, the two groups of protrusions are spaced apart in the width direction of the first shell wall, and an exhaust channel is defined between the two groups of protrusions. In the length direction of the first shell wall, the exhaust channel is located on opposite sides of the pressure relief structure.

[0029] In the above technical solution, by dividing multiple protrusions on the same side of the pressure relief structure into two groups of protrusions spaced apart along the width direction of the first shell wall, and defining exhaust channels on opposite sides of the pressure relief structure along the length direction of the first shell wall between the two groups of protrusions, gas from other locations inside the battery casing can be guided by the exhaust channels to quickly reach the pressure relief structure, so that the pressure relief structure can be opened in time.

[0030] In some embodiments, the exhaust passage has a first centerline extending along the length direction of the first shell wall, and the pressure relief structure has a second centerline extending along the length direction of the first shell wall, wherein the projection of the first centerline onto the first shell wall coincides with the projection of the second centerline onto the first shell wall.

[0031] In the above technical solution, by making the center line of the exhaust channel extending along the length of the first shell wall coincide with the center line of the pressure relief structure extending along the length of the first shell wall, the gas in other positions inside the battery shell can be quickly guided to the center of the pressure relief structure through the exhaust channel, which further enables the pressure relief structure to open in time and allows the gas to be concentrated in the middle of the pressure relief structure and discharged quickly.

[0032] In some embodiments, both the first shell wall and the protruding structure are made of metal, and an insulating layer is provided on the side of the electrode assembly facing the first shell wall.

[0033] In the above technical solution, by making the first shell wall a metal material, the structural strength of the first shell wall can be increased, reducing the deformation of the first shell wall; by making the protruding structure a metal material, the strength of the protruding structure can be increased, and the metal protruding structure has better heat resistance than the plastic material, so that the protruding structure can be stably supported between the first shell wall and the electrode assembly, and the size of the exhaust space formed between the first shell wall and the electrode assembly can be better maintained; and at the same time, an insulating layer is provided on the side of the electrode assembly facing the first shell wall, which can achieve insulation between the first shell wall and the protruding structure and the electrode assembly, avoiding short circuits and other problems.

[0034] In some embodiments, the pressure relief structure includes a grooved structure formed on the first shell wall.

[0035] In the above technical solution, by making the pressure relief structure include a grooved structure formed on the first shell wall, when the air pressure at the pressure relief structure is large, for example, when the opening pressure of the pressure relief structure is reached, the pressure relief structure opens. Since the grooved structure is a weak point in the battery shell structure, the grooved structure is destroyed under the action of air pressure to form an exhaust hole, thereby realizing directional exhaust. This pressure relief structure is simple and easy to process.

[0036] Furthermore, when setting the serrated structure on the first shell wall, due to manufacturing issues, the serration process causes the position of the serrated structure on the first shell wall to be recessed. Correspondingly, the position of the serrated structure on the first shell wall protrudes relative to the electrode assembly, making the protrusion height of the protrusion structure relative to the first shell wall higher than that of the serrated structure relative to the first shell wall. In this way, the space between the first shell wall and the electrode assembly is opened up by the protrusion structure, resulting in a larger exhaust space between the first shell wall and the electrode assembly. Gas generated during the operation of the battery cell can reach the vicinity of the pressure relief structure more smoothly through the exhaust space. Moreover, because the protrusion height of the protrusion structure relative to the first shell wall is higher than that of the serrated structure relative to the first shell wall, the side of the pressure relief structure facing the electrode assembly is separated from the electrode assembly. In this way, gas reaching the vicinity of the pressure relief structure can smoothly enter the pressure relief structure through the gap between the pressure relief structure and the electrode assembly, and be discharged in time through the pressure relief structure, achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving battery safety.

[0037] In some embodiments, the pressure relief structure and the terminal of the battery cell are located on opposite sides of the battery casing.

[0038] In the above technical solution, by placing the pressure relief structure and the terminal post of the battery cell on opposite sides of the battery casing, the impact of the pressure relief structure on the terminal post during the venting process can be reduced. Furthermore, since the pressure relief structure and the terminal post are not on the same side of the battery casing, the tabs of the electrode assembly and the connection structure between the tabs and the terminal post are also not on the same side of the pressure relief structure. In this way, the tabs of the electrode assembly, the part of the terminal post located inside the battery casing, and the connection structure between the tabs and the terminal post will not occupy the space between the first casing wall and the electrode assembly. This results in a larger venting space between the first casing wall and the electrode assembly, a more regular venting space, less venting resistance, and smoother venting.

[0039] In some embodiments, the battery housing includes a main housing, a first end cap, and a second end cap, which are respectively formed independently. The first end cap and the second end cap are respectively disposed on opposite sides of the main housing, and the first end cap constitutes the first housing wall.

[0040] In the above technical solution, by setting the battery casing as a main casing, a first end cap and a second end cap that are formed independently, and setting the pressure relief structure on the first end cap, since the processing and forming process of the first end cap is relatively independent of the main casing and the second end cap, it is convenient to set the pressure relief structure on the first end cap. Even if the pressure relief structure is not set properly on the first end cap, only the first end cap needs to be reprocessed instead of the entire battery casing, which can reduce the production cost of materials.

[0041] Secondly, this application provides a battery, comprising: the battery cell described in the first aspect of this application.

[0042] In the above technical solution, by setting the aforementioned battery cell, the gas generated by the battery cell during operation can reach the pressure relief structure more smoothly and be discharged in time through the pressure relief structure, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0043] Thirdly, this application provides an electrical device, including: the battery described in the second aspect of this application.

[0044] In the above technical solution, by setting up the battery, the gas generated by the battery cell when it is working can reach the pressure relief structure more smoothly and be discharged in time through the pressure relief structure, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0045] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0046] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0047] Figure 1 is a schematic diagram of a battery cell according to some embodiments of this application;

[0048] Figure 2 is a schematic diagram of the first shell wall and protrusion structure of the battery cell in Figure 1;

[0049] Figure 3 is a front view of the first shell wall and the protruding structure in Figure 2;

[0050] Figure 4 is a side view of the first shell wall and the protruding structure in Figure 2;

[0051] Figure 5 is a schematic diagram of a battery according to some embodiments of this application;

[0052] Figure 6 is a schematic diagram of an electrical device according to some embodiments of this application.

[0053] Reference numerals: 1000, electrical device; 200, battery; 100, battery cell; 10, battery casing; 11, first casing wall; 12, pressure relief structure; 13, protruding structure; 131, boss; 14, exhaust channel; 21, main casing; 22, first end cap; 23, second end cap; 24, terminal post. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0055] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0056] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0057] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0058] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0059] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0060] In this application, "multiple" means two or more (including two).

[0061] In this application, a battery refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include battery cells, battery modules, or battery packs. Some batteries may include a housing for encapsulating one or more battery cells or multiple battery modules; the housing may include a top plate and a bottom plate. The housing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells. Of course, some batteries may not require the aforementioned housing and may be directly installed within the battery mounting compartment of the electrical device.

[0062] In this application, the battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited to these. Battery cells are generally divided into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these.

[0063] In related technologies, batteries generate high-temperature gases during operation. To prevent excessive pressure inside the battery cells, pressure relief structures are usually installed on the battery cells to reduce the internal pressure, thereby reducing the risk of thermal runaway and improving battery safety.

[0064] However, in related technologies, the gas generated during battery cell operation cannot smoothly reach the pressure relief structure. This prevents the gas inside the battery cell from being discharged in a timely manner, leading to a large accumulation of high-temperature gas inside the cell and increasing the risk of thermal runaway. Furthermore, when the internal pressure of the battery cell increases to a certain level, it can cause damage to the cell casing at locations other than the pressure relief structure, resulting in non-directional pressure relief. This increases the risk of non-directional pressure relief and lowers the battery's safety.

[0065] Based on this, the applicant proposes a battery cell, including a battery casing and an electrode assembly, wherein the electrode assembly is disposed within the battery casing. The battery casing includes a first casing wall 11, which defines a venting space between itself and the electrode assembly. The first casing wall has a pressure relief structure, and a protruding structure is provided on the side of the first casing wall facing the electrode assembly. In the direction from the first casing wall to the electrode assembly, the protruding structure is closer to the electrode assembly than the pressure relief structure.

[0066] The aforementioned battery cell structure, by providing a protruding structure on the inner side of the first shell wall with a pressure relief structure, makes the protruding structure closer to the electrode assembly than the pressure relief structure. This protruding structure expands the space between the first shell wall and the electrode assembly, creating a larger venting space. Gas generated during battery cell operation can smoothly reach the vicinity of the pressure relief structure through this venting space. Furthermore, because the protruding structure is closer to the electrode assembly than the pressure relief structure, the side of the pressure relief structure facing the electrode assembly is separated from the electrode assembly. This allows gas reaching the vicinity of the pressure relief structure to smoothly enter the pressure relief structure through the gap between the pressure relief structure and the electrode assembly, and then be promptly discharged through the pressure relief structure. This achieves directional pressure relief, reduces the risk of non-directional pressure relief, reduces the risk of thermal runaway, and improves battery safety.

[0067] The batteries disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. The power system of such electrical devices can be composed of batteries disclosed in this application to ensure the safety and reliability of the electrical devices.

[0068] For example, the electrical devices disclosed in the embodiments of this application may be, but are not limited to, vehicles, mobile phones, tablets, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles may be fuel-powered vehicles, natural gas vehicles, new energy vehicles, or rail vehicles. New energy vehicles may be pure electric vehicles, hybrid vehicles, or range-extended vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0069] The following description, with reference to the accompanying drawings, describes a battery cell 100 according to an embodiment of this application.

[0070] Referring to Figures 1-2, in a first aspect, this application provides a battery cell 100, including a battery housing 10 and an electrode assembly, the electrode assembly being disposed within the battery housing 10. The battery housing 10 includes a first housing wall 11, which defines a venting space between the first housing wall 11 and the electrode assembly. A pressure relief structure 12 is provided on the first housing wall 11, and a protrusion structure 13 is provided on the side of the first housing wall 11 facing the electrode assembly. In the direction from the first housing wall 11 to the electrode assembly, the protrusion structure 13 is closer to the electrode assembly than the pressure relief structure 12.

[0071] When the battery cell 100 is working, when the pressure inside the battery cell 100 reaches a certain level, the pressure relief structure 12 opens to release pressure, thereby preventing the pressure inside the battery cell 100 from becoming too high and allowing the battery cell 100 to work more stably and reliably.

[0072] For example, in the example of Figure 4, the protrusion height of the protrusion structure 13 relative to the first shell wall 11 is h1, and the protrusion height of the pressure relief structure 12 relative to the first shell wall 11 is h2, where h1 is greater than h2.

[0073] The pressure relief structure 12 can protrude from the inner wall surface of the first shell wall 11. For example, when the pressure relief structure 12 is formed on the first shell wall 11 by scoring, due to the characteristics of the process, the pressure relief structure 12 formed by scoring will be relatively concave inward, thus making the pressure relief structure 12 protrude from the inner wall surface of the first shell wall 11. When the pressure relief structure 12 is formed on the first shell wall 11 by scoring, since the pressure relief structure 12 is a weak point in the structure of the battery casing 10, opening the pressure relief structure 12 means that the pressure relief structure 12 is damaged to form a vent.

[0074] The first shell wall 11 has a protruding structure 13 on the side facing the electrode assembly, which can be understood as the first shell wall 11 having a protruding structure 13 on the inner side.

[0075] In the above technical solution, by providing a protruding structure 13 on the inner side of the first shell wall 11 with the pressure relief structure 12, the protruding structure 13 is closer to the electrode assembly than the pressure relief structure 12. In this way, the protruding structure 13 expands the space between the first shell wall 11 and the electrode assembly, so that there is a larger exhaust space between the first shell wall 11 and the electrode assembly. The gas generated when the battery cell 100 is working can reach the vicinity of the pressure relief structure 12 more smoothly through the exhaust space. Furthermore, since the protruding structure 13 is closer to the electrode assembly than the pressure relief structure 12, the side of the pressure relief structure 12 facing the electrode assembly is separated from the electrode assembly. In this way, the gas reaching the vicinity of the pressure relief structure 12 can smoothly enter the pressure relief structure 12 through the gap between the pressure relief structure 12 and the electrode assembly, and be discharged in time through the pressure relief structure 12, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery 200.

[0076] In some embodiments, the protrusion height of the protrusion structure 13 relative to the first shell wall 11 is h1, and the volume of the battery cell 100 is V, wherein h1 and V satisfy: 3.563 × 10 -7 ≤h1 / V≤4.254×10 -6 .

[0077] Where h1 is in mm and V is in mm. 3 The ratio of h1 / V is a unitless ratio.

[0078] When the battery cell 100 is working, the gas generated inside the battery cell 100 can reach the pressure relief structure 12 through the exhaust space, and be discharged through the pressure relief structure 12 after the pressure relief structure 12 is opened.

[0079] It is understandable that the volume of the exhaust space (i.e., the exhaust space defined between the first shell wall 11 and the electrode assembly) is positively correlated with the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11. When the cross-sectional area of ​​the protrusion structure 13 is constant, the larger the protrusion height h1 of the first shell wall 11 is, the larger the volume of the exhaust space. The larger the volume of the exhaust space is, the more conducive it is to achieve rapid directional pressure relief from the pressure relief structure 12. When the cross-sectional area of ​​the protrusion structure 13 is constant, the smaller the protrusion height h1 of the first shell wall 11 is, the smaller the volume of the exhaust space.

[0080] The cross-sectional area of ​​the protruding structure 13 is explained as follows: the cross-sectional area of ​​the section obtained by cutting the protruding structure 13 with a reference plane is the cross-sectional area of ​​the protruding structure 13. The reference plane is a plane perpendicular to the protrusion height direction of the protruding structure 13 relative to the first shell wall 11. When the protruding structure 13 includes multiple bosses 131, the cross-sectional area of ​​the protruding structure 13 refers to the sum of the cross-sectional areas of all the multiple bosses 131.

[0081] h1 and V satisfy: 3.563 × 10 -7 ≤h1 / V≤4.254×10 -6 For example, the value of h1 / V can be 3.563 × 10 -7 4.563×10 -7 5.563×10 -7 6.563×10 -7 7.563×10 -7 8.563×10 -7 9.563×10 -7 1.563×10 -6 2.563×10 -6 3.563×10 -6 4.254×10 -6 wait.

[0082] The volume V of the battery cell 100 can be measured in the following way:

[0083] For example, when the shape of the battery cell 100 is relatively regular, the dimensions of the battery cell 100 can be directly measured and calculated. For instance, if the shape of the battery cell 100 is a cuboid or cube, the length, width, height, or side length of the battery cell 100 can be measured. When the battery cell 100 is a cuboid, the volume V of the battery cell 100 ≈ length × width × height. For instance, if the shape of the battery cell 100 is cylindrical, the height and diameter or radius of the battery cell 100 can be measured. The volume V of the battery cell 100 ≈ base area × height, where base area = π × r 2 , where r is the radius of the battery cell 100.

[0084] In the above technical solution, the ratio of the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 is h1 / V ≥ 3.563 × 10⁻⁶. -7This design allows for a larger exhaust space, enabling the gas generated during battery cell 100 operation to reach the vicinity of pressure relief structure 12 more smoothly. This reduces the pressure difference between the gas near pressure relief structure 12 and other locations within the battery casing 10, allowing pressure relief structure 12 to open promptly and release pressure, thus achieving better directional pressure relief. Furthermore, by ensuring that the ratio of the protrusion height h1 of the protrusion structure 13 relative to the first casing wall 11 to the volume V of the battery cell 100 is h1 / V ≤ 4.254 × 10⁻⁶, the overall design achieves this. -6 This avoids the energy density of the battery cell 100 being affected by an excessively large exhaust space. Thus, the ratio of the protrusion height of the protrusion structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 is set to 3.563 × 10⁻⁶. -7 ~4.254×10 -6 While achieving better directional pressure relief and reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance the energy density of battery 200, resulting in higher energy density and improved overall performance of battery 200.

[0085] In some embodiments, the electrode assembly includes a positive electrode sheet, which includes a positive electrode active material. When the positive electrode active material includes an olivine-type compound, h1 and V satisfy: 3.563 × 10⁻⁶. -7 ≤h1 / V≤3.260×10 -6 .

[0086] The olivine-type compound can be selected from at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium iron phosphate, a mixture of lithium iron manganese phosphate, and products of lithium iron phosphate doped with other elements. This type of electrode assembly exhibits relatively mild thermal runaway behavior and a slow rate of thermal runaway gas generation; h1 and V satisfy: 3.563 × 10⁻⁶. -7 ≤h1 / V≤3.260×10 -6 For example, the value of h1 / V can be 3.563 × 10⁻⁶. -7 4.563×10 -7 5.563×10 -7 6.563×10 -7 7.563×10 -7 8.563×10 -7 9.563×10 -7 1.563×10 -6 2.563×10 -6 3.260×10 -6 wait.

[0087] In the above technical solution, when the positive electrode active material of the electrode assembly includes an olivine-type compound, the rate at which the battery cell 100 generates gas during operation is relatively slow, and its thermal runaway behavior is relatively mild. This is achieved by setting the ratio h1 / V of the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 to 3.563 × 10⁻⁶. -7 ~3.260×10 -6 Based on the characteristics of the battery cell 100 containing olivine-type compound positive electrode active material, the ratio of the protrusion height of the protrusion structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set to be smaller. This allows the battery cell 100 containing olivine-type compound positive electrode active material to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing the energy density of the battery 200, resulting in a higher energy density and improved overall performance of the battery 200.

[0088] In some embodiments, the electrode assembly includes a positive electrode sheet, which includes a positive electrode active material. When the positive electrode active material includes a layered compound, h1 and V satisfy: 7.125 × 10⁻⁶. -7 ≤h1 / V≤4.254×10 -6 .

[0089] Among them, the layered compound can be a ternary material, including cobalt-free high-nickel compounds and compounds composed of nickel / manganese / cobalt / lithium aluminate in any proportion. This type of electrode assembly has a high energy density, significantly deteriorates thermal runaway behavior, and exhibits a sharp increase in internal thermal runaway gas production and gas production rate. h1 and V can satisfy: 7.125 × 10 -7 ≤h1 / V≤4.254×10 -6 For example, the value of h1 / V can be 7.125 × 10⁻⁶. -7 8.125×10 -7 9.125×10 -7 1.125×10 -6 2.125×10 -6 3.125×10 -6 4.254×10 -6 wait.

[0090] In the above technical solution, when the positive electrode active material of the electrode assembly includes a layered compound, the rate at which the battery cell 100 generates gas during operation is relatively rapid, and its thermal runaway behavior is relatively worse. This is mitigated by setting the ratio h1 / V of the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 to 7.125 × 10⁻⁶. -7 ~4.254×10 -6Based on the characteristics of the battery cell 100 containing layered compound positive electrode active material, the ratio of the protrusion height of the protrusion structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set to be larger. This allows the battery cell 100 containing layered compound positive electrode active material to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing the energy density of the battery 200, resulting in a higher energy density and improved overall performance of the battery 200.

[0091] In some embodiments, the electrode assembly includes a negative electrode sheet, which includes a negative electrode active material. When the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly does not contain Si, h1 and V satisfy 7.125 × 10⁻⁶. -7 ≤h1 / V≤3.973×10 -6 .

[0092] h1 and V satisfy: 7.125 × 10 -7 ≤h1 / V≤3.973×10 -6 For example, the value of h1 / V can be 7.125 × 10⁻⁶. -7 8.125×10 -7 9.125×10 -7 1.125×10 -6 2.125×10 -6 3.125×10 -6 3.973×10 -6 wait.

[0093] In the above technical solution, when the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly does not contain Si, the gas generation rate of the battery cell 100 during operation is relatively rapid, and its thermal runaway behavior is more severe. The energy density of the negative electrode active material of the electrode assembly without Si is relatively lower than that of the negative electrode active material containing Si, and the gas generation rate and thermal runaway behavior of the battery cell 100 during operation are relatively milder. This is achieved by setting the ratio h1 / V of the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 to 7.125 × 10⁻⁶. -7 ~3.973×10 -6Based on the characteristics of the battery cell 100, which includes a layered compound positive electrode active material and whose negative electrode active material of the electrode assembly does not contain Si, the ratio of the protrusion height of the protrusion structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set more reasonably. This allows the battery cell 100, which includes a layered compound positive electrode active material and whose negative electrode active material of the electrode assembly does not contain Si, to better achieve directional pressure relief and better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing the energy density of the battery 200, resulting in a higher energy density and improved overall performance of the battery 200.

[0094] In some embodiments, the electrode assembly includes a negative electrode sheet, the negative electrode sheet includes a negative electrode active material, and when the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly contains Si, h1 and V satisfy 8.529 × 10⁻⁶. -7 ≤h1 / V≤4.254×10 -6 .

[0095] When the positive electrode active material of the electrode assembly includes layered compounds and the negative electrode active material contains Si, the energy density of this type of electrode assembly is further increased compared to when the negative electrode active material does not contain Si. However, thermal runaway behavior is further worsened, and the volume requirement for the exhaust space is further increased. h1 and V satisfy: 8.529 × 10⁻⁶. -7 ≤h1 / V≤4.254×10 -6 For example, the value of h1 / V can be 8.529 × 10 -7 9.529×10 -7 1.529×10 -6 2.529×10 -6 3.529×10 -6 4.254×10 -6 wait.

[0096] In the above technical solution, when the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly contains Si, the rate of gas generation during operation of the battery cell 100 is relatively rapid, and its thermal runaway behavior is relatively worse. The energy density of the negative electrode active material containing Si is relatively higher than that of the negative electrode active material without Si, and the rate of gas generation and thermal runaway behavior of the battery cell 100 during operation are also relatively worse. This is achieved by setting the ratio h1 / V of the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 to 8.529 × 10⁻⁶. -7 ~4.254×10 -6Based on the characteristics of the battery cell 100, which includes a layered compound positive electrode active material and a negative electrode active material containing Si, the ratio of the protrusion height of the protrusion structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set more reasonably. This allows the battery cell 100, which includes a layered compound positive electrode active material and a negative electrode active material containing Si, to better achieve directional pressure relief and better reduce the risk of non-directional pressure relief and thermal runaway, while also better balancing the energy density of the battery 200, resulting in a higher energy density and improved overall performance of the battery 200.

[0097] In some embodiments, referring to FIG3, the projection of the protrusion structure 13 on the first shell wall 11 is the first projection, and the projection of the pressure relief structure 12 on the first shell wall 11 is the second projection. The distance between the first projection and the second projection is not less than 2 mm.

[0098] For example, referring to FIG3, the distance between the protruding structure 13 and the pressure relief structure 12 is shown to be d, where d is greater than or equal to 2 mm.

[0099] In the above technical solution, by ensuring that the distance between the projection of the protruding structure 13 on the first shell wall 11 and the projection of the pressure relief structure 12 on the first shell wall 11 is not less than 2mm, interference between the protruding structure 13 and the pressure relief structure 12 can be prevented. At the same time, the space near the pressure relief structure 12 is larger, and the exhaust is smoother.

[0100] In some embodiments, the protruding structure 13 is integrally formed with the first shell wall 11; or, the protruding structure 13 and the first shell wall 11 are separately provided.

[0101] In the above technical solution, by making the protruding structure 13 integrally formed with the first shell wall 11, the assembly process between the protruding structure 13 and the first shell wall 11 can be eliminated, improving production efficiency and making the connection between the protruding structure 13 and the first shell wall 11 more stable; or, by making the protruding structure 13 and the first shell wall 11 separately set, with the protruding structure 13 being formed independently relative to the first shell wall 11 and then connected and assembled to the first shell wall 11, the setting of the protruding structure 13 on the first shell wall 11 can be more flexible.

[0102] In some embodiments, referring to Figures 2-4, the protrusion structure 13 includes a plurality of spaced protrusions 131.

[0103] In the above technical solution, by setting the protruding structure 13 as a plurality of spaced protrusions 131, the first shell wall 11 and the electrode assembly can have uniform and stable support, and the exhaust space of each part can be distributed more evenly, so that the gas in different positions in the battery shell 10 can reach the pressure relief structure 12 more smoothly.

[0104] In some embodiments, referring to Figures 2-4, the first shell wall 11 is rectangular, and a plurality of protrusions 131 are distributed on opposite sides of the pressure relief structure 12 along the length direction of the first shell wall 11.

[0105] For example, referring to Figures 2-4, the length direction of the first shell wall 11 is the e1 direction shown in Figures 2-4.

[0106] In the above technical solution, when the first shell wall 11 is rectangular, the pressure relief structure 12 has a long exhaust path on both sides along the length of the first shell wall 11. Most of the gas in other locations inside the battery casing 10 reaches the pressure relief structure 12 through the exhaust path on both sides along the length of the first shell wall 11. This results in multiple protrusions 131 being distributed on both sides of the pressure relief structure 12 along the length of the first shell wall 11. This allows the exhaust space on both sides of the pressure relief structure 12 along the length of the first shell wall 11 to be opened by the multiple protrusions 131, so that the gas in other locations inside the battery casing 10 can reach the pressure relief structure 12 more smoothly through the exhaust space.

[0107] In some embodiments, referring to Figures 2-4, in the length direction of the first shell wall 11, a plurality of bosses 131 located on the same side of the pressure relief structure 12 are divided into two groups of bosses. Each group of bosses includes at least one boss 131. The two groups of bosses are arranged at intervals along the width direction of the first shell wall 11, and an exhaust channel 14 is defined between the two groups of bosses. In the length direction of the first shell wall 11, the exhaust channel 14 is located on opposite sides of the pressure relief structure 12.

[0108] For example, referring to Figures 2-4, the width direction of the first shell wall 11 is the e2 direction shown in Figures 2-4.

[0109] Each group of bosses includes at least one boss 131. For example, each group of bosses may include one boss 131 that extends along the length direction of the first shell wall 11. Or, for example, each group of bosses may include multiple bosses 131 that are spaced apart along the length direction of the first shell wall 11.

[0110] In the above technical solution, by dividing the multiple protrusions 131 on the same side of the pressure relief structure 12 into two groups of protrusions spaced apart along the width direction of the first shell wall 11, and defining the exhaust channels 14 on opposite sides of the pressure relief structure 12 in the length direction of the first shell wall 11 between the two groups of protrusions, the gas in other locations inside the battery casing 10 can be guided by the exhaust channels 14 to quickly reach the pressure relief structure 12, so that the pressure relief structure 12 can be opened in time.

[0111] In some embodiments, referring to FIG3, the exhaust channel 14 has a first centerline extending along the length direction of the first shell wall 11, and the pressure relief structure 12 has a second centerline extending along the length direction of the first shell wall 11. The projection of the first centerline on the first shell wall 11 coincides with the projection of the second centerline on the first shell wall 11.

[0112] For example, referring to FIG3, the projection of the first center line of the exhaust channel 14 onto the first shell wall 11 is s1, and the projection of the second center line of the pressure relief structure 12 onto the first shell wall 11 is s2. The projections s1 and s2 of the first center line onto the first shell wall 11 both extend along the length direction of the first shell wall 11 and coincide.

[0113] In the above technical solution, by making the center line of the exhaust channel 14 extending along the length direction of the first shell wall 11 coincide with the center line of the pressure relief structure 12 extending along the length direction of the first shell wall 11, the gas in other positions inside the battery casing 10 can be quickly guided to the center of the pressure relief structure 12 through the guiding effect of the exhaust channel 14, thereby enabling the pressure relief structure 12 to open in time and allowing the gas to concentrate in the middle of the pressure relief structure 12 and be quickly discharged.

[0114] In some embodiments, the first shell wall 11 and the protrusion structure 13 are both made of metal, and an insulating layer is provided on the side of the electrode assembly facing the first shell wall 11.

[0115] For example, the first shell wall 11 and the protruding structure 13 are both made of aluminum or steel.

[0116] In the above technical solution, by making the first shell wall 11 a metal material, the structural strength of the first shell wall 11 can be increased, reducing the deformation of the first shell wall 11; by making the protruding structure 13 a metal material, the strength of the protruding structure 13 can be increased, and the metal protruding structure 13 has better heat resistance than the plastic material, so that the protruding structure 13 can be stably supported between the first shell wall 11 and the electrode assembly, and the size of the exhaust space formed between the first shell wall 11 and the electrode assembly can be better maintained; and at the same time, an insulating layer is provided on the side of the electrode assembly facing the first shell wall 11, which can achieve insulation between the first shell wall 11 and the protruding structure 13 and the electrode assembly, avoiding short circuits and other problems.

[0117] In some embodiments, the pressure relief structure 12 includes a grooved structure formed on the first shell wall 11.

[0118] In the above technical solution, by making the pressure relief structure 12 include a grooved structure formed on the first shell wall 11, when the air pressure at the pressure relief structure 12 is large, for example, when the opening pressure of the pressure relief structure 12 is reached, the pressure relief structure 12 opens. Since the grooved structure is a weak point in the structure of the battery shell 10, the grooved structure is destroyed under the action of air pressure to form an exhaust hole, thereby realizing directional exhaust. The pressure relief structure 12 is simple and easy to process.

[0119] Furthermore, when the scoring structure is set on the first shell wall 11, due to manufacturing issues, the scoring process causes the scoring structure on the first shell wall 11 to be recessed. Consequently, the scoring structure on the first shell wall 11 protrudes relative to the first shell wall 11 toward the electrode assembly, making the protrusion height of the protrusion structure 13 relative to the first shell wall 11 higher than the protrusion height of the scoring structure relative to the first shell wall 11. In this way, the protrusion structure 13 expands the space between the first shell wall 11 and the electrode assembly, providing a larger exhaust space between the first shell wall 11 and the electrode assembly, which is beneficial for the gas generated when the battery cell 100 is working. The gas can reach the vicinity of the pressure relief structure 12 relatively smoothly through the exhaust space. Furthermore, by making the protrusion height of the protrusion structure 13 relative to the first shell wall 11 higher than the protrusion height of the grooved structure relative to the first shell wall 11, the side of the pressure relief structure 12 facing the electrode assembly can be separated from the electrode assembly. In this way, the gas reaching the vicinity of the pressure relief structure 12 can smoothly enter the pressure relief structure 12 through the gap between the pressure relief structure 12 and the electrode assembly, and be discharged in time through the pressure relief structure 12, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery 200.

[0120] In some embodiments, the pressure relief structure 12 and the terminal post 24 of the battery cell 100 are located on opposite sides of the battery casing 10.

[0121] In the above technical solution, by placing the pressure relief structure 12 and the terminal post 24 of the battery cell 100 on opposite sides of the battery casing 10, the impact of the pressure relief structure 12 on the terminal post 24 during the venting process can be reduced. Furthermore, since the pressure relief structure 12 and the terminal post 24 are not on the same side of the battery casing 10, the tabs of the electrode assembly and the connection structure between the tabs and the terminal post 24 are not on the same side of the pressure relief structure 12. In this way, the tabs of the electrode assembly, the part of the terminal post 24 located inside the battery casing 10, and the connection structure between the tabs and the terminal post 24 will not occupy the space between the first casing wall 11 and the electrode assembly, thereby making the venting space between the first casing wall 11 and the electrode assembly larger, the venting space more regular, the venting resistance lower, and the venting smoother.

[0122] In some embodiments, the battery housing 10 includes a main housing 21, a first end cap 22, and a second end cap 23, which are formed independently. The first end cap 22 and the second end cap 23 are respectively covered on opposite sides of the main housing 21, and the first end cap 22 constitutes the first housing wall 11.

[0123] In the above technical solution, by setting the battery casing 10 as a main casing 21, a first end cap 22, and a second end cap 23 that are formed independently, and setting the pressure relief structure 12 on the first end cap 22, since the processing and forming process of the first end cap 22 is relatively independent of the main casing 21 and the second end cap 23, it is convenient to set the pressure relief structure 12 on the first end cap 22. Even if the pressure relief structure 12 is not set properly on the first end cap 22, only the first end cap 22 needs to be reprocessed without reprocessing the entire battery casing 10, which can reduce the production cost of materials.

[0124] The battery cell 100 according to some embodiments of the present application is described below with reference to Figures 1-4.

[0125] In this embodiment, the battery cell 100 is a stacked battery 200. The battery cell 100 includes a battery casing 10 and an electrode assembly. The electrode assembly is formed by stacking multiple electrode sheets sequentially. The battery casing 10 is a rectangular casing. The battery casing 10 includes a main casing 21, a first end cap 22, and a second end cap 23, which are respectively formed independently. The first end cap 22 and the second end cap 23 are respectively disposed on opposite sides of the main casing 21. Both the first end cap 22 and the second end cap 23 are rectangular. The first end cap 22 and the main casing 21 are metal parts, and at least a portion of the second end cap 23 is made of metal. The first end cap 22 is provided with a pressure relief structure 12, which is a groove structure formed on the first end cap 22. The second end cap 23 is provided with two spaced-apart terminals 24, which are a positive terminal 24 and a negative terminal 24, respectively.

[0126] The length direction of the first end cap 22 and the second end cap 23 extends along the first direction (refer to the e1 direction in the figure), and the width direction of the first end cap 22 and the second end cap 23 extends along the second direction (refer to the e2 direction in the figure). The first end cap 22 and the second end cap 23 are located on opposite sides of the shell body along the third direction (refer to the e3 direction in the figure).

[0127] The first end cap 22 has a raised structure 13 on its inner side, and an insulating layer is provided on the side of the electrode assembly facing the first shell wall 11. The raised structure 13 is in contact with the insulating layer. The protrusion height of the raised structure 13 relative to the first shell wall 11 is higher than the protrusion height of the pressure relief structure 12 relative to the first shell wall 11. The raised structure 13 is integrally formed with the first shell wall 11, and the distance between the raised structure 13 and the pressure relief structure 12 is not less than 2 mm.

[0128] The protruding structure 13 includes a plurality of spaced protrusions 131, which are distributed on opposite sides of the pressure relief structure 12 along the length of the first shell wall 11. Along the length of the first shell wall 11, the protrusions 131 on the same side of the pressure relief structure 12 are divided into two groups of protrusions. Each group of protrusions includes a plurality of protrusions 131 arranged along the length of the first shell wall 11. The two groups of protrusions are spaced apart along the width of the first shell wall 11, and an exhaust channel 14 is defined between the two groups of protrusions. Along the length of the first shell wall 11, the exhaust channel 14 is located on opposite sides of the pressure relief structure 12.

[0129] A venting space is defined between the first shell wall 11 and the electrode assembly. The protrusion height of the protrusion structure 13 relative to the first shell wall 11 is h1, and the volume of the battery cell 100 is V. h1 and V satisfy: 3.563 × 10 -7 ≤h1 / V≤4.254×10 -6 .

[0130] In this embodiment, the battery cell 100 has a large venting space between the first shell wall 11 and the electrode assembly. When the battery cell 100 is working, the gas generated can reach the vicinity of the pressure relief structure 12 relatively smoothly through the venting space. Furthermore, by making the protruding structure 13 closer to the electrode assembly than the pressure relief structure 12, the side of the pressure relief structure 12 facing the electrode assembly can be separated from the electrode assembly. In this way, the gas reaching the vicinity of the pressure relief structure 12 can smoothly enter the pressure relief structure 12 through the gap between the pressure relief structure 12 and the electrode assembly, and be discharged in time through the pressure relief structure 12, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery 200.

[0131] Furthermore, by making the ratio of the protrusion height h1 of the protrusion structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 3.563 × 10-7 ≤h1 / V≤4.254×10 -6 While achieving better directional pressure relief and reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance the energy density of battery 200, resulting in higher energy density and improved overall performance of battery 200.

[0132] The following describes directional pressure relief tests performed on battery cells according to some embodiments of this application to further illustrate the battery cells of this application.

[0133] I. The following explanation will be based on a battery cell whose positive electrode active material includes olivine-type compounds.

[0134] In the experiment of this embodiment, a battery cell with a capacity of 100Ah and dimensions of 39mm*203mm*117mm was selected. The positive electrode active material of the battery cell includes lithium iron phosphate. The dimension of the battery cell 100 is 203mm in the first direction, 39mm in the second direction, and 117mm in the third direction. The protrusion structure 13 includes eight protrusions 131. The length L of the protrusion 131 is 30mm, and the width W of the protrusion 131 is 10mm. The length and width of the protrusion 131 are fixed, and the height h1 of the protrusion 131 is changed (the height h1 of the protrusion 131 is the height h1 of the protrusion structure 13). Thermal runaway of the battery cell 100 was triggered by arranging a heating film inside the battery cell 100. The triggering power was 300W. The test was conducted to see whether the battery cell 100 could achieve directional pressure relief. The test results are shown in Table 1.

[0135] Table 1

[0136] In this embodiment, seven sets of tests were designed. The difference between the battery cells 100 in each set of tests lies in the height of the protrusion 131. Due to the different heights of the protrusion 131, the volume of the exhaust space is different. Ten identical battery cells 100 were used in each set of tests. As shown in the test results in Table 1, the ratio h1 / V of the height h1 of the protrusion structure 13 to the volume V of the battery cell 100 is greater than or equal to 3.563 × 10⁻⁶. -7 At this time, the directional pressure relief rate is relatively high, basically achieving directional pressure relief. Furthermore, considering the energy density of the battery cell 100, the ratio of the height h1 of the protruding structure 13 to the volume V of the battery cell 100, h1 / V, is greater than 3.260 × 10⁻⁶. -6 At this time, although the directional pressure relief rate is relatively high, the energy density of the battery cell is not high.

[0137] The directional pressure relief rate is explained as follows: In a directional pressure relief test of a group of battery cells 100, the ratio of the number of battery cells experiencing directional pressure relief to the total number of battery cells 100 in that group is the directional pressure relief rate of that group of directional pressure relief tests. Directional pressure relief refers to the battery cells 100 releasing pressure from the pressure relief structure 12, while non-directional pressure relief refers to the battery cells 100 releasing pressure from other locations besides the pressure relief structure 12.

[0138] Therefore, when the positive electrode active material of the electrode assembly includes an olivine-type compound, the ratio h1 / V of the height h1 of the protrusion structure 13 to the volume V of the battery cell 100 is set to 3.563 × 10⁻⁶. -7 ~3.260×10 -6 While achieving better directional pressure relief and reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0139] II. The following explanation will be based on a battery cell in which the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly does not contain Si.

[0140] In the experiment of this embodiment, a battery cell with a capacity of 170Ah and dimensions of 39mm*203mm*117mm was selected. The positive electrode active material of the battery cell includes a nickel-cobalt-manganese compound. The dimension 203mm is the dimension of the battery cell 100 in the first direction, the dimension 39mm is the dimension of the battery cell 100 in the second direction, and the dimension 117mm is the dimension of the battery cell 100 in the third direction. The protrusion structure 13 includes eight protrusions 131. The length L of the protrusion 131 is 30mm, the width W of the protrusion 131 is 10mm, the length and width of the protrusion 131 are fixed, and the height h1 of the protrusion 131 is changed (the height h1 of the protrusion 131 is the height h1 of the protrusion structure 13). Thermal runaway of the battery cell 100 was triggered by arranging a heating film inside the battery cell 100. The triggering power was 300W. The test was conducted to see whether the battery cell 100 could achieve directional pressure relief. The test results are shown in Table 2.

[0141] Table 2

[0142] In this embodiment, seven sets of tests were designed. The difference between the battery cells 100 in each set of tests lies in the height of the protrusion 131. Due to the different heights of the protrusion 131, the volume of the exhaust space is different. Ten identical battery cells 100 were used in each set of tests. As shown in Table 2, the ratio h1 / V of the height h1 of the protrusion structure 13 to the volume V of the battery cell 100 is greater than or equal to 7.125 × 10⁻⁶. -7At this time, the directional pressure relief rate is relatively high, basically achieving directional pressure relief. Furthermore, the ratio h1 / V of the height h1 of the protruding structure 13 to the volume V of the battery cell 100 is greater than 3.973 × 10⁻⁶. -6 At this time, although the directional pressure relief rate is relatively high, the energy density of the battery cell is not high.

[0143] Therefore, when the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly does not contain Si, the ratio h1 of the height h1 of the protrusion structure 13 to the volume V of the battery cell 100 is set to 7.125 × 10⁻⁶. -7 ~3.973×10 -6 While achieving better directional pressure relief and reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0144] III. The following is an example of a battery cell containing Si as the positive electrode active material of the electrode assembly and the negative electrode active material of the electrode assembly.

[0145] In the experiment of this embodiment, a battery cell with a capacity of 190Ah and dimensions of 39mm*203mm*117mm was selected. The positive electrode active material of the battery cell includes a nickel-cobalt-manganese compound. The dimension 203mm is the dimension of the battery cell 100 in the first direction, the dimension 39mm is the dimension of the battery cell 100 in the second direction, and the dimension 117mm is the dimension of the battery cell 100 in the third direction. The protrusion structure 13 includes eight protrusions 131. The length L of the protrusion 131 is 30mm, the width W of the protrusion 131 is 10mm, the length and width of the protrusion 131 are fixed, and the height h1 of the protrusion 131 is changed (the height h1 of the protrusion 131 is the height h1 of the protrusion structure 13). Thermal runaway of the battery cell 100 was triggered by arranging a heating film inside the battery cell 100. The triggering power was 300W. The test was conducted to see whether the battery cell 100 could achieve directional pressure relief. The test results are shown in Table 3.

[0146] Table 3

[0147] In this embodiment, seven sets of tests were designed. The difference between the battery cells 100 in each set of tests lies in the height of the protrusion 131. Due to the different heights of the protrusion 131, the volume of the exhaust space is different. Ten identical battery cells 100 were used in each set of tests. As shown in Table 3, the ratio h1 / V of the height h1 of the protrusion structure 13 to the volume V of the battery cell 100 is greater than or equal to 8.529 × 10⁻⁶. -7At this time, the directional pressure relief rate is relatively high, basically achieving directional pressure relief. Furthermore, the ratio of the height h1 of the protruding structure 13 to the volume V of the battery cell 100, h1 / V, is greater than 4.254 × 10⁻⁶. -6 At this time, although the directional pressure relief rate is relatively high, the energy density of the battery cell is not high.

[0148] Therefore, when the positive electrode active material of the electrode assembly includes a layered compound and the negative electrode active material of the electrode assembly contains Si, the ratio h1 of the height h1 of the protrusion structure 13 to the volume V of the battery cell 100 is set to 8.529 × 10⁻⁶. -7 ~4.254×10 -6 While achieving better directional pressure relief and reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance battery energy density, resulting in higher battery energy density and improved overall battery performance.

[0149] Secondly, referring to FIG5, this application provides a battery, including: the battery cell described in the first aspect of this application.

[0150] In the above technical solution, by setting the aforementioned battery cell, the gas generated by the battery cell during operation can reach the pressure relief structure more smoothly and be discharged in time through the pressure relief structure, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0151] Thirdly, referring to FIG6, this application provides an electrical device, including: the battery described in the second aspect of this application.

[0152] In the above technical solution, by setting up the battery, the gas generated by the battery cell when it is working can reach the pressure relief structure more smoothly and be discharged in time through the pressure relief structure, thereby achieving directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0153] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0154] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell, wherein, The battery cell comprises: a battery shell comprising a first shell wall, wherein a pressure relief structure is arranged on the first shell wall; an electrode assembly arranged in the battery shell, wherein an exhaust space is defined between the first shell wall and the electrode assembly; wherein a protruding structure is arranged on a side of the first shell wall facing the electrode assembly, and the protruding structure is closer to the electrode assembly than the pressure relief structure in a direction from the first shell wall to the electrode assembly.

2. The battery cell of claim 1, wherein, The convex structure has a protruding height h1 relative to the first shell wall, the battery monomer has a volume V, and h1 and V satisfy: 3.563x10 -7 ≤h1 / V≤4.254x10 -6 .

3. The battery cell of claim 2, wherein, The electrode assembly includes a positive electrode sheet including a positive electrode active material, and when the positive electrode active material includes an olivine-type compound, h1 and V satisfy: 3.563 x 10 -7 ≤ h1 / V ≤ 3.260 x 10 -6 .

4. The battery cell of claim 2, wherein, The electrode assembly includes a positive electrode sheet including a positive electrode active material, and when the positive electrode active material includes a layered compound, h1 and V satisfy: 7.125 x 10 -7 ≤ h1 / V ≤ 4.254 x 10 -6 .

5. The battery cell of claim 4, wherein, The electrode assembly includes a negative electrode sheet including a negative electrode active material, h1 and V satisfy 7.125 x 10 -7 ≤ h1 / V ≤ 3.973 x 10 -6 when the positive electrode active material includes a layered compound and the negative electrode active material does not contain Si element.

6. The battery cell of claim 4, wherein, The electrode assembly includes a negative electrode sheet including a negative electrode active material, and when the positive electrode active material includes a layered compound and the negative electrode active material contains an Si element, h1 and V satisfy 8.529 x 10 -7 ≤ h1 / V ≤ 4.254 x 10 -6 .

7. The battery cell of any one of claims 1-6, wherein, A projection of the protruding structure on the first shell wall is a first projection, a projection of the pressure relief structure on the first shell wall is a second projection, and a distance between the first projection and the second projection is not less than 2 mm.

8. The battery cell of any one of claims 1-7, wherein, The protruding structure is integrally formed with the first shell wall.

9. The battery cell of any one of claims 1-8, wherein, The protruding structure comprises a plurality of spaced protrusions.

10. The battery cell of claim 9, wherein, The first shell wall is rectangular, and the plurality of protrusions are distributed on opposite sides of the pressure relief structure along a length direction of the first shell wall.

11. The battery cell of claim 10, wherein, In the length direction of the first shell wall, the plurality of protrusions on the same side of the pressure relief structure are divided into two groups of protrusions, each group of protrusions comprises at least one protrusion, and the two groups of protrusions are arranged spaced apart in a width direction of the first shell wall, and an exhaust passage is defined between the two groups of protrusions, and the exhaust passage is located on opposite sides of the pressure relief structure in the length direction of the first shell wall.

12. The battery cell of claim 11, wherein, The exhaust passage has a first center line extending in the length direction of the first shell wall, the pressure relief structure has a second center line extending in the length direction of the first shell wall, and a projection of the first center line on the first shell wall coincides with a projection of the second center line on the first shell wall.

13. The battery cell of any one of claims 1-12, wherein, The first shell wall and the protruding structure are both made of metal, and an insulating layer is arranged on a side of the electrode assembly facing the first shell wall.

14. The battery cell of any one of claims 1-13, wherein, The pressure relief structure comprises a score structure formed on the first shell wall.

15. The battery cell of any one of claims 1-14, wherein, The pressure relief structure and the pole of the battery cell are located on opposite sides of the battery shell.

16. The battery cell of any one of claims 1-15, wherein, The battery shell comprises a main shell, a first end cover and a second end cover which are independently formed, the first end cover and the second end cover are respectively arranged on opposite sides of the main shell, and the first end cover constitutes the first shell wall.

17. A battery, wherein, The battery cell according to any one of claims 1-16. The battery according to claim 17.

18. An electrical device, comprising: The battery according to claim 17. ​

Images