Battery monomer, battery and electric device

Abstract

The utility model discloses a single battery, a battery and an electric device. The single battery comprises a battery shell and an electrode assembly, the battery shell comprises a first shell wall, an exhaust space is defined between the first shell wall and the electrode assembly, a pressure relief structure is arranged on the first shell wall, the electrode assembly is arranged in the battery shell, a protruding structure is arranged on the side, facing the electrode assembly, of the first shell wall, and the pressure relief structure is arranged on the side, facing the electrode assembly, of the first shell wall in the direction from the first shell wall to the electrode assembly. The protrusion structure is closer to the electrode assembly than the pressure relief structure. According to the single battery disclosed by the embodiment of the utility model, gas generated when the single battery works can smoothly reach the pressure relief structure and is timely discharged through the pressure relief structure, so that directional pressure relief is realized, the risk of non-directional pressure relief is reduced, the risk of thermal runaway is reduced, and the safety of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell, a battery and an electric device. Background Art

[0002] In related technologies, when a battery works, gases at a relatively high temperature are generated. In order to prevent the pressure inside the battery cell from becoming too high, a pressure relief structure is usually provided on the battery cell to reduce the pressure inside the battery cell, thereby reducing the risk of thermal runaway of the battery and improving the safety of the battery.

[0003] However, in related technologies, the gases generated when the battery cell works cannot reach the pressure relief structure smoothly, so that the gases inside the battery cell cannot be discharged through the pressure relief structure in time, resulting in a large accumulation of gases at a relatively high temperature inside the battery cell, increasing the risk of thermal runaway. Moreover, when the pressure inside the battery cell increases to a certain extent, it will cause the housing of the battery cell to be damaged at other positions except the pressure relief structure, that is, non-directional pressure relief occurs, increasing the risk of non-directional pressure relief and reducing the safety of the battery.

[0004] Therefore, how to timely discharge the high-temperature gases generated when the battery cell works, reduce the risk of non-directional pressure relief, reduce the risk of thermal runaway, and improve the safety of the battery is an urgent problem to be solved. Summary of the Utility Model

[0005] The utility model provides a battery cell, a battery and an electric device. When the battery cell works, the generated gases can reach the pressure relief structure smoothly and be discharged through the pressure relief structure in time, realizing directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0006] In a first aspect, the utility model provides a battery cell, including: a battery housing, the battery housing includes a first shell wall, and a pressure relief structure is provided on the first shell wall; an electrode assembly, arranged inside the battery housing, and an exhaust space is defined between the first shell wall and the electrode assembly; wherein, a convex structure is provided on the side of the first shell wall facing the electrode assembly, and in the direction from the first shell wall to the electrode assembly, the convex structure is closer to the electrode assembly than the pressure relief structure.

[0007] In the above technical solution, by providing a convex structure on the inner side of the first shell wall provided with a pressure relief structure, the convex structure is closer to the electrode assembly than the pressure relief structure. In this way, the space between the first shell wall and the electrode assembly is expanded by the convex structure, so that there is a relatively large exhaust space between the first shell wall and the electrode assembly. The gas generated during the operation of the battery cell can smoothly reach the vicinity of the pressure relief structure through the exhaust space. And because the convex structure is closer to the electrode assembly than the pressure relief structure, the side of the pressure relief structure facing the electrode assembly can be spaced apart from the electrode assembly. In this way, the 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, realizing 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 some embodiments, the protruding height of the convex structure relative to the first shell wall is h1, and the volume of the battery cell is V. h1 and V satisfy: 3.563×10 -7 ≤h1 / V≤4.254×10 -6 .

[0009] In the above technical solution, by making the ratio h1 / V of the protruding height h1 of the convex structure relative to the first shell wall to the volume V of the battery cell satisfy h1 / V≥3.563×10 -7 , the volume of the exhaust space can be made relatively large, so that the gas generated during the operation of the battery cell can more smoothly reach the vicinity of the pressure relief structure through the exhaust space, making the pressure difference between the pressure near the pressure relief structure and other positions in the battery housing smaller, so that the pressure relief structure can be opened in time for exhaust pressure relief, and better realize directional pressure relief; by making the ratio h1 / V of the protruding height h1 of the convex structure relative to the first shell wall to the volume V of the battery cell satisfy h1 / V≤4.254×10 -6 , it is possible to avoid the volume of the exhaust space being too large and affecting the energy density of the battery cell. In this way, by making the ratio of the protruding height h1 of the convex structure relative to the first shell wall to the volume V of the battery cell be set between 3.563×10 -7 ~4.254×10 -6 , while better realizing directional pressure relief and better reducing the risks of non-directional pressure relief and thermal runaway, the battery energy density can be better balanced, making the battery energy density relatively high and improving the overall performance of the battery.

[0010] In some embodiments, the electrode assembly includes a positive electrode plate, and the positive electrode plate includes a positive electrode active material. When the positive electrode active material includes an olivine-type compound, h1 and V satisfy: 3.563×10 -7 ≤h1 / V≤3.260×10 -6 .

[0011] 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 the operation of the battery cell is relatively slow, and its thermal runaway behavior is relatively mild. By setting the ratio h1 / V of the protruding height h1 of the convex structure relative to the first housing wall to the volume V of the battery cell at 3.563×10 -7 ~3.260×10 -6 , according to the characteristics of the battery cell with a positive electrode active material including an olivine-type compound, the ratio of the protruding height of the convex structure relative to the first housing wall to the volume of the battery cell can be set smaller. In this way, for the battery cell with a positive electrode active material including an olivine-type compound, while better achieving directional pressure relief and better reducing the risk of non-directional pressure relief and thermal runaway, it can also better balance the battery energy density, resulting in a higher battery energy density and improving the overall performance of the battery.

[0012] In some embodiments, the electrode assembly includes a positive electrode sheet, and the positive electrode sheet includes a positive electrode active material. When the positive electrode active material includes a layered compound, h1 and V satisfy: 7.125×10 -7 ≤h1 / V≤4.254×10 -6 .

[0013] 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 the operation of the battery cell is relatively rapid, and its thermal runaway behavior deteriorates. By setting the ratio h1 / V of the protruding height h1 of the convex structure relative to the first housing wall to the volume V of the battery cell at 7.125×10 -7 ~4.254×10 -6 , according to the characteristics of the battery cell with a positive electrode active material including a layered compound, the ratio of the protruding height of the convex structure relative to the first housing wall to the volume of the battery cell can be set larger. In this way, for the battery cell with a positive electrode active material including a layered compound, while better achieving directional pressure relief and better reducing the risk of non-directional pressure relief and thermal runaway, it can also better balance the battery energy density, resulting in a higher battery energy density and improving the overall performance of the battery.

[0014] In some embodiments, the electrode assembly includes a negative electrode sheet, and the negative electrode sheet includes a negative electrode active material. When the positive electrode active material includes a layered compound and the negative electrode active material does not contain Si element, h1 and V satisfy 7.125×10 -7 ≤h1 / V≤3.973×10 -6 .

[0015] 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 element, the rate of gas generation during the operation of the battery cell is relatively rapid, and its thermal runaway behavior deteriorates. The energy density of the negative electrode active material without Si element is relatively lower than that with Si element. The rate of gas generation and the thermal runaway behavior during the operation of the battery cell are also relatively mild. By setting the ratio h1 / V of the protruding height h1 of the convex structure relative to the first shell wall to the volume V of the battery cell at 7.125×10 -7 ~3.973×10 -6 , according to the characteristics of the battery cell with a positive electrode active material including a layered compound and a negative electrode active material without Si element, the ratio of the protruding height of the convex structure relative to the first shell wall to the volume of the battery cell can be set more reasonably. In this way, for the battery cell with a positive electrode active material including a layered compound and a negative electrode active material without Si element, while better achieving directional pressure relief and better reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance the battery energy density, resulting in a relatively high battery energy density and improving the overall performance of the battery.

[0016] In some embodiments, the electrode assembly includes a negative electrode sheet, and the negative electrode sheet includes a negative electrode active material. When the positive electrode active material includes a layered compound and the negative electrode active material contains Si element, h1 and V satisfy 8.529×10 -7 ≤h1 / V≤4.254×10 -6 .

[0017] In the above technical solution, when the positive electrode active material includes a layered compound and the negative electrode active material contains Si element, the rate of gas generation during the operation of the battery cell is relatively rapid, and its thermal runaway behavior deteriorates. The energy density of the negative electrode active material with Si element is relatively higher than that without Si element. The rate of gas generation and the thermal runaway behavior during the operation of the battery cell also deteriorate relatively. By setting the ratio h1 / V of the protruding height h1 of the convex structure relative to the first shell wall to the volume V of the battery cell at 8.529×10 -7 ~4.254×10 -6 , according to the characteristics of the battery cell with a positive electrode active material including a layered compound and a negative electrode active material containing Si element, the ratio of the protruding height of the convex structure relative to the first shell wall to the volume of the battery cell can be set more reasonably. In this way, for the battery cell with a positive electrode active material including a layered compound and a negative electrode active material containing Si element, while better achieving directional pressure relief and better reducing the risks of non-directional pressure relief and thermal runaway, it can also better balance the battery energy density, resulting in a relatively high battery energy density and improving the overall performance of the battery.

[0018] In some embodiments, the projection of the convex structure on the first housing wall is a first projection, and the projection of the pressure relief structure on the first housing wall is a second projection. The distance between the first projection and the second projection is not less than 2 mm.

[0019] In the above technical solution, by making the distance between the projection of the convex structure on the first housing wall and the projection of the pressure relief structure on the first housing wall not less than 2 mm, interference between the convex structure and the pressure relief structure can be prevented, and at the same time, the space near the pressure relief structure is relatively large, making the exhaust more smooth.

[0020] In some embodiments, the convex structure is integrally formed with the first housing wall; alternatively, the convex structure is separately provided from the first housing wall.

[0021] In the above technical solution, by integrally forming the convex structure with the first housing wall, the assembly process between the convex structure and the first housing wall can be omitted, improving production efficiency, and the connection between the convex structure and the first housing wall can also be made more stable; alternatively, by separately providing the convex structure from the first housing wall, the convex structure can be independently formed relative to the first housing wall and then connected and assembled to the first housing wall, making the arrangement of the convex structure on the first housing wall more flexible.

[0022] In some embodiments, the convex structure includes a plurality of spaced-apart bosses.

[0023] In the above technical solution, by providing the convex structure as a plurality of spaced-apart bosses, a uniform and stable support can be provided between the first housing wall and the electrode assembly, and the exhaust spaces at various parts are relatively evenly distributed, enabling the gas at different positions in the battery housing to reach the pressure relief structure more smoothly.

[0024] In some embodiments, the first housing wall is rectangular, and a plurality of the bosses are distributed on opposite sides of the pressure relief structure along the length direction of the first housing wall.

[0025] In the above technical solution, when the first housing wall is rectangular, the opposite sides of the pressure relief structure along the length direction of the first housing wall have relatively long exhaust paths, and most of the gas at other positions in the battery housing reaches the pressure relief structure through the exhaust paths on the opposite sides of the pressure relief structure along the length direction of the first housing wall. By distributing a plurality of bosses on the opposite sides of the pressure relief structure along the length direction of the first housing wall, the exhaust spaces on the opposite sides of the pressure relief structure along the length direction of the first housing wall can be expanded by the plurality of bosses, and the gas at other positions in the battery housing can reach the pressure relief structure more smoothly through the exhaust spaces.

[0026] In some embodiments, in the length direction of the first housing wall, the plurality of bosses on the same side of the pressure relief structure are divided into two groups of bosses. Each group of bosses includes at least one boss. The two groups of bosses are arranged at intervals in the width direction of the first housing wall. An exhaust passage is defined between the two groups of bosses. In the length direction of the first housing wall, the exhaust passage is located on opposite sides of the pressure relief structure.

[0027] In the above technical solution, by dividing the plurality of bosses on the same side of the pressure relief structure into two groups of bosses arranged at intervals in the width direction of the first housing wall, and defining an exhaust passage between the two groups of bosses that is located on opposite sides of the pressure relief structure in the length direction of the first housing wall, the gas at other positions in the battery housing can be quickly guided to the pressure relief structure through the guiding action of the exhaust passage, enabling the pressure relief structure to be opened in a timely manner.

[0028] In some embodiments, the exhaust passage has a first center line extending in the length direction of the first housing wall, and the pressure relief structure has a second center line extending in the length direction of the first housing wall. The projection of the first center line on the first housing wall coincides with the projection of the second center line on the first housing wall.

[0029] In the above technical solution, by making the center line of the exhaust passage extending in the length direction of the first housing wall coincide with the center line of the pressure relief structure extending in the length direction of the first housing wall, the gas at other positions in the battery housing can be quickly guided to the center of the pressure relief structure through the guiding action of the exhaust passage, further enabling the pressure relief structure to be opened in a timely manner and allowing the gas to be concentrated in the middle of the pressure relief structure and discharged quickly.

[0030] In some embodiments, both the first housing wall and the raised structure are made of a metal material, and an insulating layer is provided on the side of the electrode assembly facing the first housing wall.

[0031] In the above technical solution, by making the first housing wall of a metal material, the structural strength of the first housing wall can be increased, reducing the deformation of the first housing wall. By making the raised structure of a metal material, the strength of the raised structure can be increased, and the metal material of the raised structure has better heat resistance compared to a plastic material. Thus, the raised structure can stably support between the first housing wall and the electrode assembly, enabling the size of the exhaust space formed between the first housing wall and the electrode assembly to be maintained well. And at the same time, an insulating layer is provided on the side of the electrode assembly facing the first housing wall, enabling insulation between the first housing wall and the raised structure and the electrode assembly, avoiding problems such as short circuits.

[0032] In some embodiments, the pressure relief structure includes a scoring structure formed on the first housing wall.

[0033] In the above technical solution, the pressure relief structure is formed in the form of a notch 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 notch structure is a weak point in the structure of the battery shell, the notch structure is destroyed under the action of air pressure to form an exhaust hole, thereby realizing directional exhaust. The pressure relief structure is simple and easy to process.

[0034] In addition, when a notch structure is provided on the first shell wall, due to process problems, the notch manufacturing process will cause the position of the notch structure provided on the first shell wall to be concave. Accordingly, the position of the notch structure provided on the first shell wall protrudes relative to the first shell wall toward the electrode assembly, so that the protruding height of the protruding structure relative to the first shell wall is higher than the protruding height of the notch structure relative to the first shell wall. In this way, the space between the first shell wall and the electrode assembly is expanded by the protruding structure, so that there is a larger exhaust space between the first shell wall and the electrode assembly. The gas generated when the battery cell is working can pass through the exhaust space to reach the vicinity of the pressure relief structure more smoothly. Moreover, since the protruding height of the protruding structure relative to the first shell wall is higher than the protruding height of the notch structure relative to the first shell wall, the side of the pressure relief structure facing the electrode assembly can be separated from the electrode assembly. In this way, the 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, thereby realizing directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0035] In some embodiments, the pressure relief structure and the poles of the battery cells are located on opposite sides of the battery housing.

[0036] In the above technical solution, by locating the pressure relief structure and the pole of the battery cell on opposite sides of the battery shell, the impact of the pressure relief structure on the pole during the exhaust process can be reduced; and, since the pressure relief structure and the pole are not on the same side of the battery shell, the pole ear of the electrode assembly and the connection structure between the pole ear and the pole are not on the same side as the pressure relief structure, so that the pole ear of the electrode assembly, the part of the pole located in the battery shell, and the connection structure between the pole ear and the pole will not occupy the space between the first shell wall and the electrode assembly, thereby making the exhaust space between the first shell wall and the electrode assembly larger, and the exhaust space is more regular, the exhaust resistance is smaller, and the exhaust is smoother.

[0037] In some embodiments, the battery housing includes a main housing, a first end cover, and a second end cover that are independently formed. The first end cover and the second end cover are respectively covered on opposite sides of the main housing, and the first end cover constitutes the first housing wall.

[0038] In the above technical solution, by setting the battery housing as a main housing, a first end cover, and a second end cover that are separately and independently formed, and arranging the pressure relief structure on the first end cover. Since the processing and forming process of the first end cover is relatively independent of the main housing and the second end cover, it is convenient to arrange the pressure relief structure on the first end cover. And even if the pressure relief structure is not set properly on the first end cover, only the first end cover needs to be reprocessed without reprocessing the entire battery housing, which can reduce the production cost of materials.

[0039] In a second aspect, the present utility model provides a battery, including: the battery cell of the first aspect of the present utility model described above.

[0040] In the above technical solution, by arranging the above battery cell, the gas generated when the battery cell works can reach the pressure relief structure relatively smoothly and be discharged in time through the pressure relief structure, realizing directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0041] In a third aspect, the present utility model provides an electrical device, including: the battery of the second aspect of the present utility model described above.

[0042] In the above technical solution, by arranging the above battery, the gas generated when the battery cell of the battery works can reach the pressure relief structure relatively smoothly and be discharged in time through the pressure relief structure, realizing 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] The additional aspects and advantages of the present utility model will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present utility model will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0045] Figure 1 is a schematic diagram of a battery cell according to some embodiments of the present utility model;

[0046] Figure 2 is Figure 1 a schematic diagram of the first shell wall and the convex structure of the battery cell in

[0047] Figure 3 is Figure 2 a front view of the first shell wall and the convex structure in

[0048] Figure 4 is Figure 2 a side view of the first shell wall and the convex structure in

[0049] Figure 5 is a schematic diagram of a battery according to some embodiments of the present utility model;

[0050] Figure 6 is a schematic diagram of an electrical device according to some embodiments of the present utility model.

[0051] Reference numerals:

[0052] 1000, electrical device;

[0053] 200, battery;

[0054] 100, battery cell;

[0055] 10, battery housing; 11, first housing wall; 12, pressure relief structure; 13, protrusion structure; 131, boss; 14, exhaust passage;

[0056] 21, main housing; 22, first end cap; 23, second end cap; 24, terminal post. Detailed implementation manners

[0057] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0058] Unless otherwise defined, all technical and scientific terms used in the present utility model have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs; the terms used in the description of the present utility model in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present utility model; the terms "including" and "having" and any variations thereof in the description and claims of the present utility model and the above accompanying drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of the present utility model or the above accompanying drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0059] Referring to "embodiments" in the present utility model means that specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present utility model. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0060] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", "attachment" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0061] In the present utility model, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present utility model generally represents an "or" relationship between the front and rear associated objects.

[0062] In the embodiments of the present utility model, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present utility model shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only illustrative and should not constitute any limitation to the present utility model.

[0063] The term "a plurality of" in the present utility model refers to two or more (including two).

[0064] In the present utility model, a battery refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present utility model can include battery cells, battery modules or battery packs, etc. Some batteries can include a box body for encapsulating one or more battery cells or a plurality of battery modules, and the box body can include a top plate and a bottom plate. The box body can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells. Of course, there are also some batteries that do not include the above box body and are directly arranged in the battery installation compartment of the electrical device.

[0065] In the present utility model, the battery cell can include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, etc., and the embodiments of the present utility model are not limited thereto. The battery cell can be in a cylindrical shape, a flat shape, a cuboid shape or other shapes, etc., and the embodiments of the present utility model are not limited thereto either. Generally, the battery cells are divided into three types according to the encapsulation method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present utility model are not limited thereto either.

[0066] In related technologies, batteries generate high-temperature gas when working. In order to prevent excessive pressure inside the battery cell, a pressure relief structure is usually set on the battery cell to reduce the pressure inside the battery cell, thereby reducing the risk of thermal runaway of the battery and improving the safety of the battery.

[0067] However, in related technologies, the gas generated by the battery cells during operation cannot reach the pressure relief structure smoothly. As a result, the gas inside the battery cells cannot be discharged through the pressure relief structure in a timely manner, causing a large amount of high-temperature gas to accumulate inside the battery cells, increasing the risk of thermal runaway. Furthermore, when the internal pressure of the battery cells increases to a certain level, it can cause damage to the battery cell casing in locations other than the pressure relief structure, i.e., non-directional pressure release occurs. This increases the risk of non-directional pressure release and reduces battery safety.

[0068] Based on this, the applicant proposed a battery cell comprising: a battery housing and an electrode assembly, wherein the electrode assembly is disposed within the battery housing. The battery housing includes a first housing wall, wherein the first housing wall 11 defines a vent space between the first housing wall and the electrode assembly. The first housing wall is provided with a pressure relief structure, and a protrusion structure is provided on the side of the first housing wall facing the electrode assembly. In the direction from the first housing wall to the electrode assembly, the protrusion structure is closer to the electrode assembly than the pressure relief structure.

[0069] The structure of the above-mentioned battery cell is such that a protruding structure is provided on the inner side of the first shell wall provided with a pressure relief structure, so that the protruding structure is closer to the electrode assembly than the pressure relief structure. In this way, the space between the first shell wall and the electrode assembly is expanded by the protruding structure, so that there is a larger exhaust space between the first shell wall and the electrode assembly. The gas generated when the battery cell is working can reach the vicinity of the pressure relief structure more smoothly through the exhaust space. Moreover, since 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 can be separated from the electrode assembly. In this way, the 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, thereby realizing directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0070] The battery disclosed in the embodiment of the present invention can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. The power supply system of the electrical device can be composed of the battery disclosed in the present invention to ensure the safety and reliability of the electrical device.

[0071] For example, the electrical device disclosed in the embodiments of the present utility model may be, but is not limited to, a vehicle, a mobile phone, a tablet computer, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle, a new energy vehicle or a rail vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a stationary or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, a hammer drill, an impact drill, a concrete vibrator, a planer, etc.

[0072] The battery cell 100 according to the embodiment of the present utility model will be described below with reference to the accompanying drawings.

[0073] Referring to Figures 1 - 2 , in a first aspect, the present utility model provides a battery cell 100, including: a battery housing 10 and an electrode assembly, the electrode assembly being disposed in the battery housing 10. Wherein, the battery housing 10 includes 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, and a convex structure 13 is provided on a 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 convex structure 13 is closer to the electrode assembly than the pressure relief structure 12.

[0074] Wherein, when the battery cell 100 is working, when the pressure inside the battery cell 100 reaches a certain pressure, the pressure relief structure 12 is opened to relieve the pressure, so as to avoid the pressure inside the battery cell 100 being too high, so that the battery cell 100 can work more stably and reliably.

[0075] For example, in Figure 4 example, the protruding height of the convex structure 13 relative to the first housing wall 11 is h1, and the protruding height of the pressure relief structure 12 relative to the first housing wall 11 is h2, and h1 is greater than h2.

[0076] The pressure relief structure 12 may protrude from the inner wall surface of the first housing wall 11 relative to the first housing wall 11. For example, when the pressure relief structure 12 is formed on the first housing wall 11 by means of scoring, due to the process characteristics, the pressure relief structure 12 formed by the scoring method will be recessed inward, so that the pressure relief structure 12 protrudes from the inner wall surface of the first housing wall 11 relative to the first housing wall 11. When the pressure relief structure 12 is formed on the first housing wall 11 by means of scoring, since the pressure relief structure 12 is a weak part of the structure of the battery housing 10, the opening of the pressure relief structure 12 means that the pressure relief structure 12 is damaged to form an exhaust hole.

[0077] A protruding structure 13 is provided on a side of the first shell wall 11 facing the electrode assembly, which can be understood as a protruding structure 13 is provided on an inner side of the first shell wall 11 .

[0078] In the above technical solution, a protruding structure 13 is provided on the inner side of the first shell wall 11 provided with the pressure relief structure 12, so that the protruding structure 13 is closer to the electrode assembly than the pressure relief structure 12. In this way, the space between the first shell wall 11 and the electrode assembly is expanded by the protruding structure 13, 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. Moreover, 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 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 realizing 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.

[0079] In some embodiments, the protrusion height of the protrusion structure 13 relative to the first shell wall 11 is h1, the volume of the battery cell 100 is V, and h1 and V satisfy: 3.563×10 -7 ≤h1 / V≤4.254×10 -6 .

[0080] Among them, the unit of h1 is mm, the unit of V is mm 3 The ratio h1 / V is a unitless ratio.

[0081] 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 then be discharged through the pressure relief structure 12 after the pressure relief structure 12 is opened.

[0082] It can be understood 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 protruding height h1 of the protruding structure 13 relative to the first shell wall 11. When the cross-sectional area of the protruding structure 13 is constant, the larger the protruding height h1 of the first shell wall 11, the larger the volume of the exhaust space, and the more conducive to achieving rapid and directional pressure relief from the pressure relief structure 12; when the cross-sectional area of the protruding structure 13 is constant, the smaller the protruding height h1 of the first shell wall 11, the smaller the volume of the exhaust space.

[0083] Among them, the cross-sectional area of the convex structure 13 is explained as follows: The cross-sectional area of the section obtained by intercepting the convex structure 13 with a reference plane is the cross-sectional area of the convex structure 13. The reference plane is a plane and perpendicular to the protruding height direction of the convex structure 13 relative to the first shell wall 11. When the convex structure 13 includes a plurality of convex platforms 131, the cross-sectional area of the convex structure 13 refers to the sum of the cross-sectional areas of all the plurality of convex platforms 131.

[0084] 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 and so on.

[0085] Among them, the volume V of the battery cell 100 can be measured in the following way:

[0086] 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 example, when the shape of the battery cell 100 is a cuboid or a 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 example, when 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 the base area = π×r 2 , where r is the radius of the battery cell 100.

[0087] In the above technical solution, by making the ratio h1 / V of the protruding height h1 of the convex structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 ≥ 3.563×10 -7, the volume of the exhaust space can be made relatively large, so that the gas generated when the battery cell 100 operates can reach near the pressure relief structure 12 more smoothly through the exhaust space, making the pressure difference between the pressure near the pressure relief structure 12 and the pressure at other positions inside the battery case 10 small, enabling the pressure relief structure 12 to be opened in time for exhaust pressure relief and better realizing directional pressure relief; by making the ratio h1 / V of the protruding height h1 of the protruding structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 satisfy h1 / V ≤ 4.254×10 -6 , it is possible to prevent the volume of the exhaust space from being too large and affecting the energy density of the battery cell 100. In this way, by setting the ratio of the protruding height of the protruding structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 within the range of 3.563×10 -7 ~4.254×10 -6 , while better realizing directional pressure relief and better reducing the risks of non-directional pressure relief and thermal runaway, the energy density of the battery 200 can be better balanced, making the energy density of the battery 200 relatively high and improving the overall performance of the battery 200.

[0088] In some embodiments, the electrode assembly includes a positive electrode sheet, and the positive electrode sheet includes a positive electrode active material. When the positive electrode active material includes an olivine-type compound, h1 and V satisfy: 3.563×10 -7 ≤ h1 / V ≤ 3.260×10 -6 .

[0089] Among them, 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 a product obtained by doping lithium iron phosphate with other elements. For this type of electrode assembly, its thermal runaway behavior is relatively mild, and the thermal runaway gas generation rate is relatively slow. h1 and V satisfy: 3.563×10 -7 ≤ h1 / V ≤ 3.260×10 -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 , 3.260×10 -6 , etc.

[0090] 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 the operation of the battery cell 100 is relatively slow, and its thermal runaway behavior is relatively mild. By setting the ratio h1 / V of the protruding height h1 of the protruding structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 at 3.563×10 -7 ~3.260×10 -6 , according to the characteristics of the battery cell 100 with a positive electrode active material including an olivine-type compound, the ratio of the protruding height of the protruding structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set to be relatively small. In this way, the battery cell 100 with a positive electrode active material including an olivine-type compound can better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway risk, and at the same time can better take into account the energy density of the battery 200, making the energy density of the battery 200 relatively high and improving the overall performance of the battery 200.

[0091] In some embodiments, the electrode assembly includes a positive electrode sheet, and the positive electrode sheet includes a positive electrode active material. When the positive electrode active material includes a layered compound, h1 and V satisfy: 7.125×10 -7 ≤h1 / V≤4.254×10 -6 .

[0092] Among them, the layered compound can be a ternary material, and can include cobalt-free high-nickel and lithium nickel / manganese / cobalt / aluminum oxide and compounds composed of any proportion thereof. This type of electrode assembly has a relatively high energy density, the thermal runaway behavior deteriorates significantly, the gas generation amount and gas generation rate during internal thermal runaway increase sharply, and 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 -7 , 8.125×1(0000065), 9.125×10 -7 , 9.125×10 -7 , 1.125×10 -6 , 2.125×10 -6 , 3.125×10 -6 , 4.254×10 -6 and so on.

[0093] 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 the operation of the battery cell 100 is relatively rapid, and its thermal runaway behavior deteriorates. By setting the ratio h1 / V of the protruding height h1 of the protruding structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 at 7.125×10 -7 ~4.254×10 -6, according to the characteristics of the battery cell 100 with a positive electrode active material including a layered compound, the ratio of the protruding height of the protruding structure 13 relative to the first housing wall 11 to the volume of the battery cell 100 can be set relatively large. In this way, for the battery cell 100 with a positive electrode active material including a layered compound, while better achieving directional pressure relief and better reducing the risk of non-directional pressure relief and thermal runaway, it can also better balance the energy density of the battery 200, making the energy density of the battery 200 relatively high and improving the overall performance of the battery 200.

[0094] In some embodiments, the electrode assembly includes a negative electrode sheet, and the negative electrode sheet 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 elements, h1 and V satisfy 7.125×10 -7 ≤h1 / V≤3.973×10 -6 .

[0095] 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 -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 and so on.

[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 does not contain Si elements, the rate of gas generation during the operation of the battery cell 100 is relatively rapid, and its thermal runaway behavior deteriorates. The energy density of the negative electrode active material of the electrode assembly without Si elements is relatively lower than that of the negative electrode active material of the electrode assembly containing Si elements. The rate of gas generation and the thermal runaway behavior during the operation of the battery cell 100 are also relatively mild. By setting the ratio h1 / V of the protruding height h1 of the protruding structure 13 relative to the first housing wall 11 to the volume V of the battery cell 100 between 7.125×10 -7 ~3.973×10 -6, based on the characteristics of the battery cell 100 including a layered compound as the positive electrode active material and the negative electrode active material of the electrode assembly not containing Si elements, the ratio of the protruding height of the protruding structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set more reasonably. In this way, the battery cell 100 including a layered compound as the positive electrode active material and the negative electrode active material of the electrode assembly not containing Si elements can better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, and at the same time can better take into account the energy density of the battery 200, making the energy density of the battery 200 relatively high and improving the overall performance of the battery 200.

[0097] In some embodiments, the electrode assembly includes a negative electrode sheet, and the negative electrode sheet 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 contains Si elements, h1 and V satisfy 8.529×10 -7 ≤h1 / V≤4.254×10 -6 .

[0098] 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 elements, the energy density of this type of electrode assembly is further improved compared to when the negative electrode active material does not contain Si elements, the thermal runaway behavior is further deteriorated, and the volume requirement for the exhaust space is further increased. h1 and V satisfy: 8.529×10 -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 and so on.

[0099] 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 elements, the rate of gas generation during the operation of the battery cell 100 is relatively rapid, its thermal runaway behavior is relatively deteriorated, the energy density of the negative electrode active material of the electrode assembly containing Si elements is relatively higher than that of the negative electrode active material of the electrode assembly not containing Si elements, and the rate of gas generation and thermal runaway behavior during the operation of the battery cell 100 are also relatively deteriorated. By setting the ratio h1 / V of the protruding height h1 of the protruding structure 13 relative to the first shell wall 11 to the volume V of the battery cell 100 between 8.529×10 -7 ~4.254×10 -6, according to the characteristics of the battery cell 100 including a layered compound as the positive electrode active material and the negative electrode active material of the electrode assembly containing Si element, the ratio of the protruding height of the convex structure 13 relative to the first shell wall 11 to the volume of the battery cell 100 can be set more reasonably. In this way, for the battery cell 100 including a layered compound as the positive electrode active material and the negative electrode active material of the electrode assembly containing Si element, while better achieving directional pressure relief, better reducing the risk of non-directional pressure relief and thermal runaway risk, it can also better take into account the energy density of the battery 200, making the energy density of the battery 200 relatively high and improving the overall performance of the battery 200.

[0100] In some embodiments, referring to Figure 3 , the projection of the convex 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, and the distance between the first projection and the second projection is not less than 2 mm.

[0101] For example, referring to Figure 3 , it shows that the distance between the convex structure 13 and the pressure relief structure 12 is d, and d is greater than or equal to 2 mm.

[0102] In the above technical solution, by making the distance between the projection of the convex structure 13 on the first shell wall 11 and the projection of the pressure relief structure 12 on the first shell wall 11 not less than 2 mm, interference between the convex structure 13 and the pressure relief structure 12 can be prevented, and at the same time, the space near the pressure relief structure 12 is relatively large, and the exhaust is smoother.

[0103] In some embodiments, the convex structure 13 is integrally formed with the first shell wall 11; or, the convex structure 13 is separately provided from the first shell wall 11.

[0104] In the above technical solution, by making the convex structure 13 integrally formed with the first shell wall 11, the assembly process between the convex structure 13 and the first shell wall 11 can be omitted, the production efficiency can be improved, and the connection between the convex structure 13 and the first shell wall 11 can also be relatively stable; or, by making the convex structure 13 separately provided from the first shell wall 11, after the convex structure 13 is independently formed relative to the first shell wall 11 and then connected and assembled to the first shell wall 11, the setting of the convex structure 13 on the first shell wall 11 can be more flexible.

[0105] In some embodiments, referring to Figures 2 - 4 , the convex structure 13 includes a plurality of convex platforms 131 arranged at intervals.

[0106] In the above technical solution, by setting the convex structure 13 as a plurality of spaced-apart bosses 131, a uniform and stable support can be provided between the first shell wall 11 and the electrode assembly, and the exhaust spaces at various parts are more evenly distributed, enabling the gas at different positions in the battery housing 10 to reach the pressure relief structure 12 more smoothly.

[0107] In some embodiments, referring to Figures 2 - 4 , the first shell wall 11 is rectangular, and a plurality of bosses 131 are distributed on opposite sides of the pressure relief structure 12 along the length direction of the first shell wall 11.

[0108] For example, referring to Figures 2 - 4 , the length direction of the first shell wall 11 is Figures 2 - 4 the e1 direction shown in

[0109] In the above technical solution, when the first shell wall 11 is rectangular, the opposite sides of the pressure relief structure 12 along the length direction of the first shell wall 11 have a longer exhaust path, and most of the gas at other positions in the battery housing 10 reaches the pressure relief structure 12 through the exhaust paths on the opposite sides of the pressure relief structure 12 along the length direction of the first shell wall 11. By arranging a plurality of bosses 131 on the opposite sides of the pressure relief structure 12 along the length direction of the first shell wall 11, the exhaust spaces on the opposite sides of the pressure relief structure 12 along the length direction of the first shell wall 11 can be expanded by the plurality of bosses 131, and the gas at other positions in the battery housing 10 can reach the pressure relief structure 12 more smoothly through the exhaust spaces.

[0110] In some embodiments, referring to Figures 2 - 4 , along the length direction of the first shell wall 11, the plurality of bosses 131 on the same side of the pressure relief structure 12 are divided into two groups of boss groups, each group of boss groups includes at least one boss 131, and the two groups of boss groups are arranged at intervals along the width direction of the first shell wall 11. An exhaust channel 14 is defined between the two groups of boss groups, and along the length direction of the first shell wall 11, the exhaust channel 14 is located on opposite sides of the pressure relief structure 12.

[0111] For example, referring to Figures 2 - 4 , the width direction of the first shell wall 11 is Figures 2 - 4 the e2 direction shown in

[0112] Each group of boss groups includes at least one boss 131. For example, each group of boss groups can include one boss 131 that extends along the length direction of the first shell wall 11. Alternatively, each group of boss groups can include a plurality of bosses 131 that are arranged at intervals along the length direction of the first shell wall 11.

[0113] In the above technical solution, by dividing multiple bosses 131 on the same side of the pressure relief structure 12 into two groups of boss groups arranged at intervals in the width direction of the first housing wall 11, and defining exhaust channels 14 on opposite sides of the pressure relief structure 12 in the length direction of the first housing wall 11, the gas at other positions in the battery housing 10 can quickly reach the pressure relief structure 12 under the guiding action of the exhaust channels 14, so that the pressure relief structure 12 can be opened in time.

[0114] In some embodiments, referring to Figure 3 , the exhaust channel 14 has a first center line extending in the length direction of the first housing wall 11, and the pressure relief structure 12 has a second center line extending in the length direction of the first housing wall 11. The projection of the first center line on the first housing wall 11 coincides with the projection of the second center line on the first housing wall 11.

[0115] For example, referring to Figure 3 , the projection of the first center line of the exhaust channel 14 on the first housing wall 11 is s1, and the projection of the second center line of the pressure relief structure 12 on the first housing wall 11 is s2. The projection s1 of the first center line on the first housing wall 11 and the projection s2 of the second center line on the first housing wall 11 both extend along the length direction of the first housing wall 11 and are arranged to coincide.

[0116] In the above technical solution, by making the center line of the exhaust channel 14 extending in the length direction of the first housing wall 11 coincide with the center line of the pressure relief structure 12 extending in the length direction of the first housing wall 11, the gas at other positions in the battery housing 10 can be quickly guided to the center of the pressure relief structure 12 under the guiding action of the exhaust channel 14. Further, the pressure relief structure 12 can be opened in time, and the gas can be concentrated in the middle of the pressure relief structure 12 and quickly discharged.

[0117] In some embodiments, the first housing wall 11 and the protruding structure 13 are both made of metal, and an insulating layer is provided on the side of the electrode assembly facing the first housing wall 11.

[0118] For example, the first housing wall 11 and the protruding structure 13 are both made of aluminum or steel.

[0119] In the above technical solution, by setting the first shell wall 11 to be made of metal, the structural strength of the first shell wall 11 can be increased, and the deformation of the first shell wall 11 can be reduced; by setting the protruding structure 13 to be made of metal, the strength of the protruding structure 13 can be increased, and the protruding structure 13 made of metal has better heat resistance than that made of plastic, so that the protruding structure 13 can be more stably supported between the first shell wall 11 and the electrode assembly, so that 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, so that the first shell wall 11 and the protruding structure 13 can be insulated from the electrode assembly to avoid problems such as short circuits.

[0120] In some embodiments, the pressure relief structure 12 includes a scoring structure formed on the first shell wall 11 .

[0121] In the above technical solution, the pressure relief structure 12 is formed in the form of a notch 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 notch structure is a weak point in the structure of the battery shell 10, the notch 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.

[0122] In addition, when the notch structure is provided on the first shell wall 11, due to process problems, the notch manufacturing process will cause the position of the notch structure of the first shell wall 11 to be concave. Accordingly, the position of the notch structure of the first shell wall 11 is protruded relative to the first shell wall 11 toward the electrode assembly, so that the protrusion height of the protrusion structure 13 relative to the first shell wall 11 is higher than the protrusion height of the notch structure relative to the first shell wall 11. In this way, the space between the first shell wall 11 and the electrode assembly is expanded by the protrusion structure 13, so that there is a larger exhaust space between the first shell wall 11 and the electrode assembly, and the gas generated when the battery cell 100 is working is discharged. The gas can reach the vicinity of the pressure relief structure 12 more smoothly through the exhaust space, and because the protruding height of the protruding structure 13 relative to the first shell wall 11 is higher than the protruding height of the notched 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, so that 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 realizing 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.

[0123] 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 housing 10 .

[0124] In the above technical solution, by arranging the pressure relief structure 12 and the pole column 24 of the battery cell 100 on opposite sides of the battery housing 10, the influence on the pole column 24 during the exhaust process of the pressure relief structure 12 can be reduced; moreover, since the pressure relief structure 12 and the pole column 24 are not on the same side of the battery housing 10, the pole tabs of the electrode assembly and the connection structure between the pole tabs and the pole column 24 are not on the same side as the pressure relief structure 12. In this way, the pole tabs of the electrode assembly, the part of the pole column 24 located inside the battery housing 10, and the connection structure between the pole tabs and the pole column 24 do not occupy the space between the first housing wall 11 and the electrode assembly, thereby making the exhaust space between the first housing wall 11 and the electrode assembly larger, the exhaust space more regular, the exhaust resistance smaller, and the exhaust smoother.

[0125] In some embodiments, the battery housing 10 includes a main housing 21, a first end cap 22, and a second end cap 23 that are separately and independently formed. The first end cap 22 and the second end cap 23 are respectively disposed on opposite sides of the main housing 21, and the first end cap 22 constitutes the first housing wall 11.

[0126] In the above technical solution, by setting the battery housing 10 as a main housing 21, a first end cap 22, and a second end cap 23 that are separately and independently formed, and arranging 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 housing 21 and the second end cap 23, it is convenient to arrange the pressure relief structure 12 on the first end cap 22. Moreover, 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 housing 10, which can reduce the production cost of materials.

[0127] The following refers to Figures 1 - 4 Describe the battery cell 100 according to some embodiments of the present invention.

[0128] In this embodiment, the battery cell 100 is a laminated battery 200. The battery cell 100 includes a battery housing 10 and an electrode assembly. The electrode assembly is formed by sequentially stacking a plurality of electrode plates. The battery housing 10 is a rectangular housing. The battery housing 10 includes a main housing 21, a first end cap 22, and a second end cap 23 that are separately and independently formed. The first end cap 22 and the second end cap 23 are respectively disposed on opposite sides of the main housing 21, and both the first end cap 22 and the second end cap 23 are rectangular. Both the first end cap 22 and the main housing 21 are metal parts, and at least part of the second end cap 23 is made of a metal material. A pressure relief structure 12 is provided on the first end cap 22, and the pressure relief structure 12 is a notch structure formed on the first end cap 22. Two spaced-apart pole columns 24 are provided on the second end cap 23, and the two pole columns 24 are a positive pole column 24 and a negative pole column 24 respectively.

[0129] Among them, the length directions of the first end cover 22 and the second end cover 23 extend along the first direction (refer to the e1 direction in the attached drawings), the width directions of the first end cover 22 and the second end cover 23 extend along the second direction (refer to the e2 direction in the attached drawings), and the first end cover 22 and the second end cover 23 are located on opposite sides of the housing body along the third direction (refer to the e3 direction in the attached drawings).

[0130] Among them, a convex structure 13 is provided on the inner side of the first end cover 22, an insulating layer is provided on the side of the electrode assembly facing the first housing wall 11, and the convex structure 13 is in contact with the insulating layer. The protruding height of the convex structure 13 relative to the first housing wall 11 is higher than the protruding height of the pressure relief structure 12 relative to the first housing wall 11. The convex structure 13 is integrally formed with the first housing wall 11, and the distance between the convex structure 13 and the pressure relief structure 12 is not less than 2 mm.

[0131] The convex structure 13 includes a plurality of convex platforms 131 arranged at intervals. The plurality of convex platforms 131 are distributed on opposite sides of the pressure relief structure 12 along the length direction of the first housing wall 11. In the length direction of the first housing wall 11, the plurality of convex platforms 131 on the same side of the pressure relief structure 12 are divided into two groups of convex platform groups. Each group of convex platform groups includes a plurality of convex platforms 131 arranged along the length direction of the first housing wall 11. The two groups of convex platform groups are arranged at intervals along the width direction of the first housing wall 11. An exhaust passage 14 is defined between the two groups of convex platform groups. In the length direction of the first housing wall 11, the exhaust passage 14 is located on opposite sides of the pressure relief structure 12.

[0132] An exhaust space is defined between the first housing wall 11 and the electrode assembly. The protruding height of the convex structure 13 relative to the first housing 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 .

[0133] In the battery cell 100 of this embodiment, there is a relatively large exhaust space between the first housing wall 11 and the electrode assembly. The gas generated when the battery cell 100 works can reach near the pressure relief structure 12 more smoothly through the exhaust space. And because the convex structure 13 is made 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 spaced apart from the electrode assembly. In this way, the gas reaching near 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, realizing 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.

[0134] Furthermore, by making the ratio of the protruding height h1 of the convex structure 13 relative to the first housing wall 11 to the volume V of the battery cell 100 3.563×10-7 ≤ h1 / V ≤ 4.254×10 -6 , while better achieving directional pressure relief, better reducing the risk of non-directional pressure relief and thermal runaway risk, it can better balance the energy density of the battery 200, making the energy density of the battery 200 relatively high and improving the overall performance of the battery 200.

[0135] The following conducts a directional pressure relief test on the battery cells of some embodiments of the present invention to further illustrate the battery cells of the present invention.

[0136] I. Taking the battery cell with the positive active material of the electrode assembly including olivine-type compounds as an example for illustration.

[0137] In the test of this embodiment, a battery cell with a capacity of 100 Ah and dimensions of 39 mm * 203 mm * 117 mm is selected. The positive active material of this battery cell includes lithium iron phosphate. The dimension of 203 mm is the dimension of the battery cell 100 in the first direction, the dimension of 39 mm is the dimension of the battery cell 100 in the second direction, and the dimension of 117 mm is the dimension of the battery cell 100 in the third direction. The convex structure 13 includes eight convex platforms 131. The length L of the convex platform 131 is 30 mm, and the width W of the convex platform 131 is 10 mm. The length and width of the convex platform 131 are fixed, and the height h1 of the convex platform 131 is changed (the height of the convex platform 131 is the height h1 of the convex structure 13). By arranging a heating film in the battery cell 100 to trigger thermal runaway of the battery cell 100, the trigger power is 300 W, and it is tested whether the battery cell 100 can achieve directional pressure relief. The test results are shown in Table 1.

[0138] Table 1

[0139] <![CDATA[L*W(mm 2 )]]> h1 (mm) <![CDATA[V(mm 3 )]]> h1 / V Directional pressure relief rate 300 0.33 926289 <![CDATA[3.563×10 -7 > 10 / 10 300 0.39 926289 <![CDATA[4.210×10 -7 > 10 / 10 300 0.66 926289 <![CDATA[7.125×10 -7 > 10 / 10 300 1.31 926289 <![CDATA[1.414×10 -6 > 10 / 10 300 2.63 926289 <![CDATA[2.839×10 -6 > 10 / 10 300 3.02 926289 <![CDATA[3.260×10 -6 > 10 / 10 300 3.15 926289 <![CDATA[3.401×10 -6 > 10 / 10

[0140] In the test of this embodiment, seven groups of tests are designed. The difference between the battery cells 100 in each group of tests lies in the height of the convex platform 131. Due to the different heights of the convex platform 131, the volume of the exhaust space is different. Ten identical battery cells 100 are designed for each group of tests. It can be seen from the test results in Table 1 that when the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is greater than or equal to 3.563×10 -7 , the directional pressure relief rate is relatively high, and directional pressure relief is basically achieved. In addition, considering balancing the energy density of the battery cell 100, when the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is greater than 3.260×10 -6 , although the directional pressure relief rate is relatively high, the energy density of the battery cell is not high at this time.

[0141] Among them, the explanation of the directional pressure relief rate is as follows: In the directional pressure relief test of a group of battery cells 100, the ratio of the number of battery cells with directional pressure relief to the total number of battery cells 100 in this group is the directional pressure relief rate of this group of directional pressure relief tests. Among them, directional pressure relief means that the battery cell 100 exhausts and relieves pressure from the pressure relief structure 12, and non-directional pressure relief means that the battery cell 100 exhausts and relieves pressure from other positions except the pressure relief structure 12.

[0142] 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 convex structure 13 to the volume V of the battery cell 100 is set at 3.563×10 -7 ~3.260×10 -6 , while better realizing directional pressure relief, better reducing the risk of non-directional pressure relief and thermal runaway, it can also better take into account the battery energy density, making the battery energy density higher and improving the overall performance of the battery.

[0143] Second, take 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 element as an example for description.

[0144] In the test of this embodiment, a battery cell with a capacity of 170 Ah and dimensions of 39 mm * 203 mm * 117 mm is selected. The positive electrode active material of this battery cell includes a nickel-cobalt-manganese compound. The dimension of 203 mm is the dimension of the battery cell 100 in the first direction, the dimension of 39 mm is the dimension of the battery cell 100 in the second direction, and the dimension of ll7 mm is the dimension of the battery cell 100 in the third direction. The convex structure 13 includes eight convex platforms 131. The length L of the convex platform 131 is 30 mm, and the width W of the convex platform 131 is 10 mm. The length and width of the convex platform 131 are fixed, and the height h1 of the convex platform 131 (the height of the convex platform 131 is the height h1 of the convex structure 13) is changed. The thermal runaway of the battery cell 100 is triggered by arranging a heating film in the battery cell 100, and the triggering power is 300 W. Whether the battery cell 100 can achieve directional pressure relief is tested, and the test results are shown in Table 2.

[0145] Table 2

[0146] [[ID=X]] <![CDATA[L*W(mm 2 )]]> h1 (mm) <![CDATA[V(mm 3 )]]> h1 / V Directional pressure relief rate 300 0.66 926289 <![CDATA[7.125×10 -7 > 10 / 10 300 1.05 926289 <![CDATA[1.134×10 -6 > 10 / 10 300 1.31 926289 <![CDATA[1.414×10 -6 > 10 / 10 300 2.63 926289 <![CDATA[2.839×10 -6 > 10 / 10 300 2.89 926289 <![CDATA[3.120×10 -6 > 10 / 10 300 3.68 926289 <![CDATA[3.973×10 -6 > 10 / 10 300 3.81 926289 <![CDATA[4.113×10 -6 > 10 / 10

[0147] In the test of this embodiment, seven groups of tests are designed. The difference between the battery cells 100 in each group of tests lies in the height of the convex platform 131. Due to the different heights of the convex platform 131, the volume of the exhaust space is different. Ten identical battery cells 100 are designed for each group of tests. It can be seen from the test results in Table 2 that when the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is greater than or equal to 7.125×10-7 When the ratio is high, directional pressure relief is basically achieved. Additionally, when the ratio of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is greater than 3.973×10 -6 although the directional pressure relief rate is high, the energy density of the battery cell is not high at this time.

[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 does not contain Si element, the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is set to be between 7.125×10 -7 and 3.973×10 -6 In this way, while better achieving directional pressure relief, better reducing the risk of non-directional pressure relief and thermal runaway, it can also better balance the battery energy density, resulting in a higher battery energy density and improving the overall performance of the battery.

[0149] Third, taking 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 includes Si element as an example for illustration.

[0150] In the test of this embodiment, a battery cell with a capacity of 190 Ah and dimensions of 39 mm * 203 mm * 117 mm is selected. The positive electrode active material of this battery cell includes a nickel-cobalt-manganese compound. The dimension of 203 mm is the dimension of the battery cell 100 in the first direction, the dimension of 39 mm is the dimension of the battery cell 100 in the second direction, and the dimension of 117 mm is the dimension of the battery cell 100 in the third direction. The convex structure 13 includes eight convex platforms 131. The length L of the convex platform 131 is 30 mm, and the width W of the convex platform 131 is 10 mm. The length and width of the convex platform 131 are fixed, and the height h1 of the convex platform 131 (the height of the convex platform 131 is the height h1 of the convex structure 13) is changed. The thermal runaway of the battery cell 100 is triggered by arranging a heating film in the battery cell 100, and the triggering power is 300 W. Whether the battery cell 100 can achieve directional pressure relief is tested, and the test results are shown in Table 3.

[0151] Table 3

[0152] <![CDATA[L*W(mm 2 )]]> h1 (mm) <![CDATA[V(mm 3 )]]> h1 / V Directional pressure relief rate 300 0.79 926289 <![CDATA[8.529×10 -7 > 10 / 10 300 1.05 926289 <![CDATA[1.134×10 -6 > 10 / 10 300 1.31 926289 <![CDATA[1.414×10 -6 > 10 / 10 300 2.63 926289 <![CDATA[2.839×10 -6 > 10 / 10 300 2.89 926289 <![CDATA[3.120×10 -6 > 10 / 10 300 3.94 926289 <![CDATA[4.254×10 -6 > 10 / 10 300 4.33 926289 <![CDATA[4.675×10 -6 > 10 / 10

[0153] In the test of this embodiment, seven groups of tests are designed. The difference between the battery cells 100 in each group of tests lies in the height of the convex platform 131. Due to the different heights of the convex platform 131, the volume of the exhaust space is different. Ten identical battery cells 100 are designed for each group of tests. From the test results in Table 3, it can be seen that when the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is greater than or equal to 8.529×10 -7When the directional pressure relief rate is relatively high, directional pressure relief is basically achieved. In addition, when the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is greater than 4.254×10 -6 although the directional pressure relief rate is relatively high, the energy density of the battery cell is not high at this time.

[0154] 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 element, the ratio h1 / V of the height h1 of the convex structure 13 to the volume V of the battery cell 100 is set at 8.529×10 -7 ~4.254×10 -6 to better achieve directional pressure relief, better reduce the risk of non-directional pressure relief and thermal runaway, and at the same time better balance the battery energy density, so that the battery energy density is relatively high and the overall performance of the battery is improved.

[0155] In a second aspect, with reference to Figure 5 the present utility model provides a battery, comprising: the battery cell of the first aspect of the present utility model as described above.

[0156] In the above technical solution, by providing the above battery cell, the gas generated when the battery cell works can reach the pressure relief structure smoothly and be discharged in time through the pressure relief structure, realizing directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0157] In a third aspect, with reference to Figure 6 the present utility model provides an electrical device, comprising: the battery of the second aspect of the present utility model as described above.

[0158] In the above technical solution, by providing the above battery, the gas generated when the battery cell of the battery works can reach the pressure relief structure smoothly and be discharged in time through the pressure relief structure, realizing directional pressure relief, reducing the risk of non-directional pressure relief, reducing the risk of thermal runaway, and improving the safety of the battery.

[0159] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0160] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that, Comprising: A battery housing, the battery housing includes a first housing wall, and a pressure relief structure is provided on the first housing wall; An electrode assembly, disposed within the battery housing, an exhaust space is defined between the first housing wall and the electrode assembly; Wherein, a convex structure is provided on a side of the first housing wall facing the electrode assembly, and in a direction from the first housing wall to the electrode assembly, the convex structure is closer to the electrode assembly than the pressure relief structure.

2. The battery cell according to claim 1, characterized in that, The protruding height of the protruding structure relative to the first shell wall is h1, and the volume of the battery cell is V. h1 and V satisfy: 3.563×10 -7 ≤h1 / V≤4.254×10 -6 .

3. The battery cell according to claim 2, characterized in that, The electrode assembly includes a positive electrode sheet, and the positive electrode sheet includes a positive electrode active material. When the positive electrode active material includes an olivine-type compound, h1 and V satisfy: 3.563×10 -7 ≤h1 / V≤3.260×10 -6 .

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

5. The battery cell according to claim 4, characterized in that, The electrode assembly includes a negative electrode sheet, and the negative electrode sheet includes a negative electrode active material. When the positive electrode active material includes a layered compound and the negative electrode active material does not contain Si element, h1 and V satisfy 7.125×10 -7 ≤ h1 / V ≤ 3.973×10 -6 .

6. The battery cell according to claim 4, characterized in that, The electrode assembly includes a negative electrode sheet, and the negative electrode sheet includes a negative electrode active material. When the positive electrode active material includes a layered compound and the negative electrode active material contains Si element, h1 and V satisfy 8.529×10 -7 ≤h1 / V≤4.254×10 -6 .

7. The battery cell according to claim 1, characterized in that, A first projection of the convex structure on the first housing wall is a first projection, a second projection of the pressure relief structure on the first housing 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 according to claim 1, characterized in that, The convex structure and the first housing wall are integrally formed.

9. The battery cell according to any one of claims 1-8, characterized in that, The convex structure includes a plurality of spaced-apart bosses.

10. The battery cell according to claim 9, characterized in that, The first housing wall is rectangular, and a plurality of the bosses are distributed on opposite sides of the pressure relief structure along the length direction of the first housing wall.

11. The battery cell according to claim 10, characterized in that, In the length direction of the first housing wall, a plurality of the bosses located on the same side of the pressure relief structure are divided into two groups of boss groups, each group of boss groups includes at least one of the bosses, and the two groups of boss groups are spaced apart and arranged along the width direction of the first housing wall, and an exhaust passage is defined between the two groups of boss groups. In the length direction of the first housing wall, the exhaust passage is located on opposite sides of the pressure relief structure.

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

13. The battery cell according to claim 1, characterized in that, Both the first housing wall and the convex structure are made of a metal material, and an insulating layer is provided on a side of the electrode assembly facing the first housing wall.

14. The battery cell according to any one of claims 1-8, characterized in that, The pressure relief structure includes a scoring structure formed on the first housing wall.

15. The battery cell according to any one of claims 1-8, characterized in that, The pressure relief structure and the pole post of the battery cell are located on opposite sides of the battery housing.

16. The battery cell according to any one of claims 1-8, characterized in that, The battery housing includes a main housing, a first end cap, and a second end cap that are separately formed. 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.

17. A battery, characterized in that, Comprising: The battery cell according to any one of claims 1-16.

18. An electrical device, characterized in that, Comprising: The battery according to claim 17.

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