Battery cell and battery pack

Abstract

This invention relates to the field of battery technology and discloses a battery cell and a battery pack, comprising: a housing; a cover plate, the housing and the cover plate forming a receiving cavity, the cover plate including a first segment, a second segment, and a third segment, the second segment connecting the first and third segments along the X direction, and the cover plate having a first side and a second side disposed opposite to each other along the Z direction, the second segment protruding towards the first side relative to the first and third segments, such that the side of the second segment facing the first side forms a connecting surface; an electrode assembly disposed within the receiving cavity, the side of the electrode assembly facing the cover plate having a first protrusion, the orthographic projection of the first protrusion on a projection plane perpendicular to the Z direction being located within the orthographic projection of the second segment; a terminal post mounted on the first segment; and an explosion-proof valve mounted on the third segment. In this embodiment of the invention, the battery cell forms a protrusion on the cover plate to bear external forces, reduce the probability of the terminal post being subjected to force, increase the surface area of ​​the cover plate, improve heat dissipation efficiency, and increase the volume of the electrode assembly, thereby increasing energy density.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a battery cell and a battery pack. Background Technology

[0002] In related technologies, battery cells typically have terminals on a cover plate. These terminals protrude from the cover plate, making them prone to collisions with external objects. Alternatively, when a battery cell is installed in a battery pack, the terminals of adjacent cells are connected by a contact plate. This contact plate contacts the battery pack housing. When the battery pack is subjected to an external impact, the housing transmits force to the terminals through the contact plate, which may damage or displace the terminals, affecting the safety of the battery pack. Summary of the Invention

[0003] This invention provides a battery cell and battery pack to solve the problems of direct stress on the terminals of the cover plate and poor heat dissipation in the prior art.

[0004] In a first aspect, the present invention provides a battery cell, comprising: a housing having an opening at at least one end; a cover plate connected to the housing and sealing the opening, the housing and the cover plate forming a receiving cavity, the cover plate comprising a first segment, a second segment, and a third segment, wherein along the X direction, the second segment is connected between the first segment and the third segment, and along the Z direction, the cover plate has a first side and a second side disposed opposite to each other, the second segment protruding toward the first side relative to the first segment and the third segment, such that the side of the second segment toward the first side forms a connecting surface; an electrode assembly disposed within the receiving cavity, the side of the electrode assembly facing the cover plate having a first protrusion, the orthographic projection of the first protrusion on a projection plane perpendicular to the Z direction being located within the orthographic projection of the second segment; a terminal post installed in the first segment, the terminal post being electrically connected to the electrode assembly; and an explosion-proof valve installed in the third segment.

[0005] Beneficial effects: The second section bears external forces, preventing deformation and damage to the electrode post, reducing the probability of short circuits, ensuring the working performance of the cover plate, and extending its service life. Furthermore, the second section, located between the explosion-proof valve and the electrode post, acts as a thermoelectric separator, improving the safety performance of the battery cell. The protruding second section also increases the surface area of ​​the cover plate facing the first side, thereby increasing the heat dissipation area and helping to control the battery cell temperature, extending its service life. When the length of the cover plate in the X direction is limited, the protruding second section can maximize the space for the electrode tabs inside the battery cell, thus increasing the overall capacity. In addition, by providing a first protrusion on the electrode assembly, corresponding to the second section and protruding towards the first side in the Z direction, the internal space utilization of the battery cell can be improved, increasing the volume of the electrode assembly, improving the energy density and capacity of the battery cell. Furthermore, in the X direction, the first and third sections can limit the first protrusion, increasing the fixing effect between the electrode assembly and the cover plate.

[0006] In one alternative embodiment, the first boss has an exhaust channel on the side facing the cover plate, and the exhaust channel extends through the first boss in the X direction.

[0007] Beneficial effects: Along the X direction, the exhaust channel can connect the space on the side of the first protrusion facing away from the explosion-proof valve with the explosion-proof valve. When the gas pressure inside the cell increases and the explosion-proof valve opens, the gas on the side of the first protrusion facing away from the explosion-proof valve along the X direction can flow through the exhaust channel to the explosion-proof valve and then be discharged outside the casing. This avoids the first protrusion affecting the flow of gas inside the cell, reduces the probability of gas accumulation inside the cell, improves the exhaust efficiency of the cell, and thus improves the safety of the cell.

[0008] In one alternative implementation, the width of the exhaust channel is A along the Y direction, and the width of the electrode assembly is W, where 0.1 ≤ A / W ≤ 0.15.

[0009] Beneficial effects: It can ensure the exhaust efficiency of the exhaust channel, reduce the probability of gas accumulation in the cell and thus improve the safety of the cell, and effectively increase the volume of the electrode group, improve the capacity and energy density of the cell, and make the cell have a longer battery life.

[0010] In one alternative embodiment, along the Z direction, the third segment protrudes toward the first side relative to the first segment; the pole group has a second protrusion on the side facing the cover plate, and on a projection plane perpendicular to the Z direction, the orthographic projection of the second protrusion is located within the orthographic projection of the third segment.

[0011] Beneficial effects: On the one hand, the height difference between the third and second segments in the Z direction is reduced, which can improve the stamping yield of the cover plate. On the other hand, it can improve the utilization rate of the internal space of the cell, increase the volume of the electrode group, and greatly increase the energy density and capacity of the cell.

[0012] In one alternative implementation, the height of the first boss along the Z direction is H1, which satisfies 6mm≤H1≤7mm.

[0013] Beneficial effects: It can make full use of the internal space of the battery cell, improve space utilization, effectively increase the capacity and energy density of the battery cell, and avoid the gap between the first boss and the cover plate being too small, prevent interference between the first boss and the cover plate, ensure the convenience of battery cell assembly, and improve production yield and production efficiency.

[0014] In one alternative implementation, the height of the second boss along the Z direction is H2, which satisfies 3mm≤H2≤5mm.

[0015] Beneficial effects: It can make full use of the internal space of the battery cell, improve space utilization, effectively increase the capacity and energy density of the battery cell, and avoid the gap between the second boss and the cover plate being too small, prevent interference between the second boss and the cover plate, ensure the convenience of battery cell assembly, and improve production yield and production efficiency.

[0016] In one alternative implementation, along the Z direction, the height of the first boss is H1 and the height of the second boss is H2, satisfying 0.5≤H2 / H1≤0.6.

[0017] Beneficial effects: It can make full use of the internal space of the battery cell, improve space utilization, effectively increase the capacity and energy density of the battery cell, and avoid the spacing between the electrode group and the cover plate being too small, prevent interference between the electrode group and the cover plate, ensure the convenience of battery cell assembly, and improve production yield and production efficiency.

[0018] In one optional embodiment, the cover plate includes two second segments and two first segments. Along the X direction, the two second segments are connected to opposite sides of the third segment, and the two first segments are respectively connected to the side of the two second segments away from the third segment. The pole group is provided with two first protrusions. Along the X direction, the two first protrusions are connected to opposite sides of the second protrusions. On a projection plane perpendicular to the Z direction, the orthographic projections of the two first protrusions are respectively located within the orthographic projections of the two second segments.

[0019] Beneficial effects: Increasing the number of first protrusions can increase the volume of the electrode group, improve the utilization rate of the internal space of the cell, and greatly increase the energy density and capacity of the cell.

[0020] In one optional embodiment, the electrode assembly includes an electrode assembly body and an electrode tab. The electrode tab is connected to the side of the electrode assembly body facing the cover plate, and the electrode tab is electrically connected to the electrode post. On a projection plane perpendicular to the Z direction, the orthographic projection of the electrode tab is located within the orthographic projection of the first segment.

[0021] Beneficial effects: In the X direction, the first and third segments can limit the first protrusion, reduce the probability of relative movement between the electrode group and the cover plate, thereby reducing the probability of electrode tab damage caused by electrode group movement and extending the service life of the battery cell.

[0022] In one optional embodiment, when the tab extends along the Z direction, the height of the tab along the Z direction is H3, satisfying 12.5mm≤H3≤15mm.

[0023] Beneficial effects: It can ensure the reliability of the connection between the tabs and the electrode assembly, the stability of the cell's working performance, and avoid interference between the tabs and the cover plate, ensuring the convenience of cell assembly and improving production yield and efficiency.

[0024] In one optional embodiment, the electrode tab has a bent portion, and the distance between the bent portion and the edge of the electrode assembly body along the Y direction is a, satisfying 6mm≤a≤10mm; and / or, along the Y direction, the width of the electrode assembly is W, 0.15≤a / W≤0.25.

[0025] Beneficial effects: It can ensure that there is sufficient distance between the tab and the shell, avoid the tab from contacting the shell after bending, reduce the risk of short circuit in the cell, and ensure that the side walls of the cover plate and the shell are roughly on the same plane in the Y direction during the welding of the tabs, effectively supporting and positioning the cover plate and the shell, and improving the reliability of the welding of the tabs and the poles.

[0026] In one optional embodiment, the battery cell further includes an insulating member. Along the Z direction, the insulating member is disposed on the side of the cover plate facing the electrode assembly. The side of the insulating member facing the electrode tab has a clearance groove. On a projection plane perpendicular to the Z direction, the orthographic projection of the electrode tab is located within the orthographic projection of the clearance groove. The insulating member forms groove walls on opposite sides of the clearance groove along the Y direction. Along the Y direction, the distance between each groove wall and the electrode tab is B, where 2mm ≤ B ≤ 5mm.

[0027] Beneficial effects: It can ensure sufficient spacing between the electrode lugs and the slot wall, reduce the probability of interference, improve assembly efficiency and production yield, ensure the structural strength of the insulating components, reduce the probability of damage to the insulating components, and ensure the insulation effect between the insulating components and the electrode group and the cover plate.

[0028] Secondly, the present invention also provides a battery pack including the aforementioned battery cell.

[0029] Beneficial effects: The battery pack using the above-mentioned cells can reduce the probability of short circuits and also has the advantages of high heat dissipation efficiency and large capacity. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is one of the connection diagrams of the cover plate, pole, explosion-proof valve and insulating component in an embodiment of the present invention.

[0032] Figure 2 This is the second schematic diagram showing the connection of the cover plate, pole, explosion-proof valve and insulating component in an embodiment of the present invention.

[0033] Figure 3 This is one of the structural schematic diagrams of the battery cell according to an embodiment of the present invention.

[0034] Figure 4 This is a second schematic diagram of the battery cell structure according to an embodiment of the present invention.

[0035] Figure 5 for Figure 4 A sectional view along line AA. Figure 6 for Figure 4 Sectional view along line BB; Figure 7 This is one of the schematic diagrams of the pole assembly in an embodiment of the present invention.

[0036] Figure 8 This is a second schematic diagram of the pole assembly in an embodiment of the present invention.

[0037] Figure 9 This is the third schematic diagram of the pole assembly in an embodiment of the present invention.

[0038] Figure 10 This is the fourth schematic diagram of the pole assembly in an embodiment of the present invention.

[0039] Figure 11 This is the fifth schematic diagram of the pole assembly in an embodiment of the present invention.

[0040] Figure 12 This is the sixth schematic diagram of the pole assembly in an embodiment of the present invention.

[0041] Figure 13 This is the seventh schematic diagram of the pole assembly in an embodiment of the present invention.

[0042] Figure 14 This is the eighth schematic diagram of the pole assembly in an embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures: 1. Battery cell; 200. Cover plate; 210. First section; 220. Second section; 230. Third section; 300, pole assembly; 310, first boss; 311, exhaust channel; 320, second boss; 330, pole assembly body; 340, pole lug; 341, bending section; 400, pole; 500, Explosion-proof valve; 600. Insulating parts; 610. Void-avoiding groove. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The terms "first," "second," etc., are used for descriptive purposes only and have no sequential or technical meaning, nor should they be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Directional terms used in this application, such as "upper" and "lower," are merely for reference to the orientation shown in the accompanying drawings. The use of directional terms is for better and clearer explanation and understanding of this application, and not to indicate the orientation of the referred device or component in a practical application scenario.

[0046] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0047] In the embodiments of this application, "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0048] The terms "parallel" and "perpendicular" are relative to the current technological level, not absolute mathematical definitions. Slight deviations are permissible; approximations of parallelism or perpendicularity are acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, with the angle between them ranging from 0 to 5 degrees. Similarly, "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, with the angle between them ranging from 85 to 95 degrees.

[0049] The term "electrical connection" refers to the flow of current or signal from one conductor to another. An electrical connection between A and B means that current or signal can flow from A to B and vice versa. This connection includes direct and indirect electrical connections. A direct electrical connection between A and B means that A and B are physically connected. An indirect electrical connection between A and B means that A and B are connected via C, where C can be at least one wire or device.

[0050] The following is combined with Figures 1 to 14The following describes embodiments of the present invention.

[0051] According to an embodiment of the present invention, in one aspect, a battery cell 1 is provided, the battery cell 1 including a housing, a cover plate 200, an electrode group 300, an electrode post 400 and an explosion-proof valve 500.

[0052] The housing has an opening at at least one end. A cover plate 200 is connected to the housing and seals the opening. The housing and cover plate 200 together form a receiving cavity. The cover plate 200 includes a first segment 210, a second segment 220, and a third segment 230. Along the X direction, the second segment 220 connects the first segment 210 and the third segment 230. Along the Z direction, the cover plate 200 has a first side and a second side that are opposite to each other. The second segment 220 protrudes towards the first side relative to the first segment 210 and the third segment 230, so that the side of the second segment 220 facing the first side forms a connecting surface. The electrode assembly 300 is disposed in the receiving cavity. The side of the electrode assembly 300 facing the cover plate 200 has a first boss 310. On a projection plane perpendicular to the Z direction, the orthographic projection of the first boss 310 is located within the orthographic projection of the second segment 220. The pole post 400 is installed in the first segment 210 and is electrically connected to the electrode assembly 300. The explosion-proof valve 500 is installed in the third segment 230.

[0053] For example, the second segment 220 can be formed using a conical stamping process. Conical stamping is easy to achieve and can improve the production yield of the cover plate 200.

[0054] In this embodiment of the invention, along the Z direction, the second segment 220 is protruding towards the first side relative to the first segment 210 and the third segment 230. The second segment 220 is used to bear external forces, avoiding deformation and damage to the terminal post 400 due to force, reducing the probability of short circuit, ensuring the working performance of the cover plate 200, and extending the service life of the cover plate 200. For example, when the cell 1 with the cover plate 200 is installed in the battery pack, the second segment 220 of the cover plate 200 abuts against the battery pack housing, wherein the second segment 220 and the battery pack housing can be bonded together.

[0055] In addition, the second section 220 is located between the explosion-proof valve 500 and the pole post 400. That is, the second section 220 isolates the explosion-proof valve 500 and the pole post 400, which plays a role in thermal and electrical separation, improving the safety performance of the battery cell 1. Furthermore, the protrusion of the second section 220 can increase the surface area of ​​the cover plate 200 facing the first side, thereby increasing the heat dissipation area of ​​the cover plate 200, which is beneficial to controlling the temperature of the battery cell 1 and extending its service life. At the same time, when the length of the cover plate 200 in the X direction is limited, the protrusion of the second section 220 can maximize the space for the inner tab 340 of the battery cell 1, thereby increasing the overall capacity of the package.

[0056] Furthermore, by providing a first protrusion 310 on the electrode assembly 300, with the first protrusion 310 corresponding to the second segment 220 and the first protrusion 310 protruding towards the first side in the Z direction, the internal space utilization of the cell 1 can be improved, the volume of the electrode assembly 300 can be increased, and the energy density and capacity of the cell 1 can be improved. In the X direction, the first segment 210 and the third segment 230 can limit the first protrusion 310, thereby increasing the fixing effect between the electrode assembly 300 and the cover plate 200.

[0057] In some embodiments, such as Figure 7 , Figure 8 , Figures 11-13 As shown, the first boss 310 has an exhaust channel 311 on the side facing the cover plate 200, and the exhaust channel 311 passes through the first boss 310 in the X direction.

[0058] Along the X direction, the exhaust channel 311 can connect the space on the side of the first protrusion 310 facing away from the explosion-proof valve 500 with the explosion-proof valve 500. When the gas pressure inside the battery cell 1 increases and the explosion-proof valve 500 opens, the gas on the side of the first protrusion 310 facing away from the explosion-proof valve 500 along the X direction can flow through the exhaust channel 311 to the explosion-proof valve 500 and then be discharged outside the housing. This prevents the first protrusion 310 from affecting the flow of gas inside the battery cell 1, reduces the probability of gas accumulation inside the battery cell 1, improves the exhaust efficiency of the battery cell 1, and thus improves the safety of the battery cell 1.

[0059] Along the Y direction, the width of the exhaust channel 311 is A, and the width of the electrode group 300 is W, where 0.1 ≤ A / W ≤ 0.15. Here, A / W can be any value from 0.1, 0.11, 0.12, 0.13, 0.14, or 0.15, or a value between any two values. Specifically, the unit of A is mm, and the unit of W is mm.

[0060] If A / W is less than 0.1, the width of the exhaust channel 311 in the Y direction is too small compared to the width of the electrode group 300, resulting in poor gas flow efficiency in the exhaust channel 311. When the gas pressure inside the cell 1 increases and the explosion-proof valve 500 opens, there is a problem that the gas cannot be discharged in time through the exhaust channel 311, affecting the safety of the cell 1. If A / W is greater than 0.15, the width of the exhaust channel 311 in the Y direction is too large compared to the width of the electrode group 300, reducing the volume of the first protrusion 310 and causing a decrease in the capacity and energy density of the cell 1.

[0061] Therefore, by limiting the value of A / W to the range of 0.1 to 0.15, it is possible to ensure the exhaust efficiency of the exhaust channel 311, reduce the probability of gas accumulation in the cell 1, thereby improving the safety of the cell 1, and effectively increase the volume of the electrode group 300, thereby increasing the capacity and energy density of the cell 1 and making the cell 1 have a stronger driving range.

[0062] For example, such as Figures 7-11 As shown, the battery cell 1 may include only one electrode group 300. In this case, the exhaust channel 311 may be located on one side of the first boss 310 in the Y direction, or the exhaust channel 311 may be located at the center of the first boss 310 in the Y direction; as Figures 12-14 As shown, the battery cell 1 may include multiple electrode groups 300, which are stacked along the Y direction, and two adjacent electrode groups 300 together define an exhaust channel 311.

[0063] In some embodiments, such as Figure 1 , Figure 5 , Figure 7 , Figure 10 ,like Figures 12-14 As shown, along the Z direction, the third segment 230 protrudes towards the first side relative to the first segment 210. The pole group 300 has a second boss 320 on the side facing the cover plate 200. On the projection plane perpendicular to the Z direction, the orthographic projection of the second boss 320 is located within the orthographic projection of the third segment 230.

[0064] In this way, on the one hand, the height difference between the third segment 230 and the second segment 220 in the Z direction is reduced, which can improve the stamping yield of the cover plate 200. On the other hand, the internal space utilization of the battery cell 1 is improved, which can increase the volume of the electrode group 300 and greatly increase the energy density and capacity of the battery cell 1.

[0065] In some embodiments, such as Figure 9 As shown, along the Z direction, the height of the first boss 310 is H1, which satisfies 6mm≤H1≤7mm. H1 can be any value among 6mm, 6.1mm, 6.2mm, 6.3mm, 6.4mm, 6.5mm, 6.6mm, 6.7mm, 6.8mm, 6.9mm, or 7mm, or a value between any two of these.

[0066] If H1 is less than 6mm, the height of the first protrusion 310 in the Z direction is too small, which does not fully utilize the internal space of the cell 1, resulting in low space utilization and a reduction in the capacity and energy density of the cell 1. If H1 is greater than 7mm, the height of the first protrusion 310 in the Z direction is too large, and the distance between the first protrusion 310 and the cover plate 200 is too small. Interference may occur between the first protrusion 310 and the cover plate 200, affecting the assembly of the cell 1 and reducing both the production yield and production efficiency.

[0067] Therefore, by limiting H1 to a value within the range of 6mm to 7mm, it is possible to fully utilize the internal space of the cell 1, improve space utilization, effectively increase the capacity and energy density of the cell 1, and avoid the gap between the first protrusion 310 and the cover plate 200 being too small, prevent interference between the first protrusion 310 and the cover plate 200, ensure the ease of assembly of the cell 1, and improve production yield and production efficiency.

[0068] Along the Z direction, the height of the second boss 320 is H2, which satisfies 3mm ≤ H2 ≤ 5mm. Here, H2 can be any value of 3mm, 3.5mm, 4mm, 4.5mm or 5mm, or a value between any two of these values.

[0069] If H2 is less than 3mm, the height of the second protrusion 320 in the Z direction is too small, which does not fully utilize the internal space of the cell 1, resulting in low space utilization and a reduction in the capacity and energy density of the cell 1. If H2 is greater than 5mm, the height of the second protrusion 320 in the Z direction is too large, and the distance between the second protrusion 320 and the cover plate 200 is too small. Interference may occur between the second protrusion 320 and the cover plate 200, affecting the assembly of the cell 1 and reducing both the production yield and production efficiency.

[0070] Therefore, by limiting H2 to a value within the range of 3mm to 5mm, it is possible to fully utilize the internal space of the battery cell 1, improve space utilization, effectively increase the capacity and energy density of the battery cell 1, and avoid the gap between the second protrusion 320 and the cover plate 200 being too small, prevent interference between the second protrusion 320 and the cover plate 200, ensure the ease of assembly of the battery cell 1, and improve production yield and production efficiency.

[0071] Along the Z direction, 0.5 ≤ H2 / H1 ≤ 0.6. Wherein, H2 / H1 can be any value among 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59 or 0.6, or a value between any two values.

[0072] If H2 / H1 is less than 0.5, the height of the second protrusion 320 in the Z direction is too small, failing to fully utilize the internal space of the cell 1, resulting in a decrease in the capacity and energy density of the cell 1. Alternatively, if the height of the first protrusion 310 is too large, the probability of interference between the first protrusion 310 and the cover plate 200 increases, leading to a decrease in both production yield and production efficiency. If H2 / H1 is greater than 0.6, the height of the second protrusion 320 in the Z direction is too large, increasing the probability of interference between the second protrusion 320 and the cover plate 200, resulting in a decrease in both production yield and production efficiency. Alternatively, if the height of the first protrusion 310 is too small, failing to fully utilize the internal space of the cell 1, resulting in a decrease in both the capacity and energy density of the cell 1.

[0073] Therefore, by limiting the value of H2 / H1 to the range of 0.5 to 0.6, we can make full use of the internal space of the cell 1, improve the space utilization rate, effectively increase the capacity and energy density of the cell 1, and avoid the spacing between the electrode group 300 and the cover plate 200 being too small, prevent interference between the electrode group 300 and the cover plate 200, ensure the ease of assembly of the cell 1, and improve the production yield and production efficiency.

[0074] In some embodiments, such as Figure 1 , Figures 7-14 As shown, the cover plate 200 includes two second segments 220 and two first segments 210. Along the X direction, the two second segments 220 are connected to opposite sides of the third segment 230, and the two first segments 210 are respectively connected to the side of the two second segments 220 away from the third segment 230. The pole assembly 300 is provided with two first protrusions 310. Along the X direction, the two first protrusions 310 are connected to opposite sides of the second protrusions 320. On the projection plane perpendicular to the Z direction, the orthographic projections of the two first protrusions 310 are respectively located within the orthographic projections of the two second segments 220.

[0075] This increases the number of first protrusions 310, which increases the volume of electrode group 300, improves the internal space utilization of cell 1, and greatly increases the energy density and capacity of cell 1.

[0076] In some embodiments, Figures 7-14 As shown, the pole group 300 includes a pole group body 330 and a pole tab 340. The pole tab 340 is connected to the side of the pole group body 330 facing the cover plate 200. The pole tab 340 is electrically connected to the pole post 400. On the projection plane perpendicular to the Z direction, the orthographic projection of the pole tab 340 is located within the orthographic projection of the first segment 210.

[0077] Specifically, on the projection plane perpendicular to the Z direction, the orthographic projections of the two tabs 340 and the first tab 340 are respectively located within the orthographic projections of the two first segments 210. Along the X direction, the two tabs 340 are located on opposite sides of the first boss 310 and the second boss 320.

[0078] In this way, a first protrusion 310 is set on the electrode group 300, and the first protrusion 310 is set in correspondence with the second segment 220. In the X direction, the first segment 210 and the third segment 230 can limit the first protrusion 310, reduce the probability of relative movement between the electrode group 300 and the cover plate 200, thereby reducing the probability of the electrode tab 340 being damaged due to the movement of the electrode group 300, and extending the service life of the battery cell 1.

[0079] Specifically, when the tab 340 extends along the Z direction, its height along the Z direction is H3, satisfying 12.5mm ≤ H3 ≤ 15mm. Here, H3 can be any value among 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, or 15mm, or a value between any two of these values.

[0080] The height of tab 340 refers to its height along the Z-direction when it is not bent. Tab 340 and post 400 can be welded together.

[0081] If H3 is less than 12.5mm, the height of tab 340 in the Z direction will be too small, which may result in a small connection area between tab 340 and post 400, leading to low overcurrent efficiency and affecting the working performance of cell 1. If H3 is greater than 15mm, the height of tab 340 in the Z direction will be too large, which may cause interference between tab 340 and cover plate 200, affecting the assembly of cell 1 and reducing both production yield and production efficiency.

[0082] Therefore, by limiting H3 to a value within the range of 12.5mm to 15mm, it is possible to ensure the reliability of the connection between the tab 340 and the electrode group 300, the stable working performance of the cell 1, and to avoid interference between the tab 340 and the cover plate 200, thereby ensuring the ease of assembly of the cell 1 and improving production yield and efficiency.

[0083] The electrode tab 340 has a bent portion 341. Along the Y direction, the distance between the bent portion 341 and the edge of the electrode assembly body 330 is 'a', which satisfies 6mm ≤ a ≤ 10mm. Here, 'a' can be any value among 6mm, 7mm, 8mm, 9mm, or 10mm, or a value between any two values.

[0084] It should be noted that the distance between the edge of the bending part 341 and the edge of the pole assembly body 330 refers to the distance between the edge of the pole assembly body 330 that is closest to the bending part 341 and the bending part 341 in the Y direction, which is the closing eccentricity of the pole tab 340.

[0085] If a is less than 6mm, then in the Y direction, the bent portion 341 of the tab 340 is too close to the housing, and it is easy for the tab 340 to come into contact with the housing after bending, which may cause a short circuit in cell 1. If a is greater than 10mm, then in the Y direction, the bent portion 341 of the tab 340 is too far away from the housing. When the tab 340 and the terminal post 400 are welded, the sidewalls of the cover plate 200 and the housing are obviously misaligned in the Y direction, making it difficult to effectively support and position the cover plate 200 and the housing, thus affecting the welding reliability of the tab 340 and the terminal post 400.

[0086] Therefore, by limiting the value of 'a' to the range of 6mm to 10mm, it is possible to ensure that the bent portion 341 of the tab 340 and the housing have sufficient spacing, avoiding contact between the tab 340 and the housing after bending, thus reducing the risk of short circuit in the cell 1. Furthermore, when welding the tabs 340 together, it is possible to ensure that the sidewalls of the cover plate 200 and the housing in the Y direction are approximately on the same plane, effectively supporting and positioning the cover plate 200 and the housing, thereby improving the welding reliability of the tab 340 and the pole post 400.

[0087] Along the Y direction, the width of the pole group 300 is W, where 0.15 ≤ a / W ≤ 0.25. W can be 24mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, or 66.66mm. a / W can be any value among 0.15, 0.2, or 0.25, or a value between any two of these values.

[0088] If a / W is less than 0.15mm, then in the Y direction, the bent portion 341 of the tab 340 is too close to the housing, and it is easy for the tab 340 to come into contact with the housing after bending, which may cause a short circuit in cell 1. If a / W is greater than 0.25, then in the Y direction, the bent portion 341 of the tab 340 is too far away from the housing. When the tab 340 and the terminal post 400 are welded, the sidewalls of the cover plate 200 and the housing are significantly misaligned in the Y direction, making it difficult to effectively support and position the cover plate 200 and the housing, thus affecting the welding reliability of the tab 340 and the terminal post 400.

[0089] Therefore, by limiting a / W to a value between 0.15 and 0.25, it is possible to ensure that the tab 340 and the housing have sufficient spacing, avoiding contact between the tab 340 and the housing after bending, thus reducing the short circuit risk of cell 1. At the same time, when welding the tabs 340, it is possible to ensure that the sidewalls of the cover plate 200 and the housing in the Y direction are approximately on the same plane, effectively supporting and positioning the cover plate 200 and the housing, and improving the welding reliability of the tab 340 and the pole 400.

[0090] In some embodiments, such as Figure 1 , Figure 2 and Figure 6 As shown, the battery cell 1 also includes an insulating member 600. Along the Z-direction, the insulating member 600 is located on the side of the cover plate 200 facing the electrode assembly 300. A clearance groove 610 is provided on the side of the insulating member 600 facing the electrode tab 340. On a projection plane perpendicular to the Z-direction, the orthographic projection of the electrode tab 340 lies within the orthographic projection of the clearance groove 610. The insulating member 600 forms groove walls on opposite sides of the clearance groove 610 along the Y-direction. Along the Y-direction, the distance between each groove wall and the electrode tab 340 is B, where 2mm ≤ B ≤ 5mm. Here, B can be any value among 2mm, 3mm, 4mm, or 5mm, or a value between any two values.

[0091] Among them, the distance between the two sides of the tab 340 along the Y direction can be B1, and the dimension of the clearance groove 610 along the Y direction can be B2, where B is equivalent to (B2-B1) / 2.

[0092] If B is less than 2mm, the distance between the tab 340 and the groove wall is too close, and interference is likely to occur between the tab 340 and the insulator 600, affecting the assembly efficiency and production yield of the cell 1. If B is greater than 5mm, the distance between the tab 340 and the groove wall is too far, the size of the clearance groove 610 in the Y direction is too large, the structural strength of the insulator 600 is low, the insulator 600 is easily damaged, and it will also affect the insulation effect between the insulator 600 and the electrode group 300 and the cover plate 200.

[0093] Therefore, by limiting B to a value within the range of 2mm to 5mm, it is possible to ensure sufficient spacing between the tab 340 and the groove wall, reduce the probability of interference, improve assembly efficiency and production yield, and also ensure the structural strength of the insulating component 600, reduce the probability of damage to the insulating component 600, and ensure the insulation effect between the insulating component 600 and the electrode group 300 and the cover plate 200.

[0094] According to an embodiment of the present invention, in another aspect, a battery pack is also provided, the battery pack including the aforementioned battery cell 1.

[0095] The battery pack of this embodiment of the invention, using the above-mentioned cell 1, can reduce the probability of short circuit and also has the advantages of high heat dissipation efficiency and large capacity.

[0096] The following observations examine the assembly of battery cells with different sizes, and simulation analyses are performed according to GB31467 and GB38031-2020 requirements. The results for the example battery cells and comparative battery cells are shown in Table 1. The example battery cells refer to those that meet the requirements of this example, while the comparative battery cells do not meet the requirements of this example.

[0097] Table 1: Test Results of the Example Cell and the Comparative Cell

[0098] As can be seen from Table 1, for the battery cell 1 of Examples 1 to 8, H1, H2, H1 / H2, a, a / W, B, and A / W are all within the range defined in this application. The test results show that the strength of each part of the cover plate 200 meets the requirements, the stress value does not change significantly, and the process yield is good.

[0099] In Comparative Example 1, a / W is less than the range. In the Y direction, the bent part 341 of the tab 340 is too close to the shell. After the tab 340 is closed, it is easy to come into contact with the shell, which causes a short circuit in cell 1.

[0100] In Comparative Example 2, when B is less than the range, in the Y direction, when the distance between the tab 340 and the groove wall of the clearance groove 610 of the insulating member 600 decreases, the tab 340 is more likely to interfere with the insulating member 600.

[0101] In Comparative Example 3, A / W is less than the range, and the width of the exhaust channel 311 along the Y direction is smaller, which affects the exhaust effect of cell 1.

[0102] In summary, when H1, H2, H1 / H2, a, a / W, B, and A / W are all within the scope defined in this application, the structural strength of the cover plate 200 can be guaranteed, and interference between the tab 340 and the cover plate 200 can be avoided, thus ensuring the exhaust effect of the battery cell 1.

[0103] Unless otherwise stated, the values ​​of all parameters mentioned in this application can be determined using testing methods commonly used in the art. Unless otherwise stated, the test temperature for all parameters is 25°C.

[0104] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: The housing has an opening at at least one end; A cover plate is connected to the housing and seals the opening. The housing and the cover plate together form a receiving cavity. The cover plate includes a first segment, a second segment, and a third segment. Along the X direction, the second segment is connected between the first segment and the third segment. Along the Z direction, the cover plate has a first side and a second side that are disposed opposite to each other. The second segment protrudes toward the first side relative to the first segment and the third segment, so that the side of the second segment facing the first side forms a connecting surface. An electrode assembly is disposed within the receiving cavity. The electrode assembly has a first protrusion on the side facing the cover plate. On a projection plane perpendicular to the Z direction, the orthographic projection of the first protrusion is located within the orthographic projection of the second segment. The electrode assembly includes an electrode assembly body and an electrode lug. The electrode lug is connected to the side of the electrode assembly body facing the cover plate. The electrode lug has a bent portion. Along the Y direction, the distance between the bent portion and the edge of the electrode assembly body is a. Along the Y direction, the width of the electrode assembly is W, where 0.15≤a / W≤0.

25. A pole post is installed in the first section, and the pole post is electrically connected to the electrode tab. An explosion-proof valve is installed in the third section; An insulating component is provided along the Z-direction on the side of the cover plate facing the electrode assembly. The side of the insulating component facing the electrode tab has a clearance groove. On a projection plane perpendicular to the Z-direction, the orthographic projection of the electrode tab is located within the orthographic projection of the clearance groove. The insulating component forms groove walls on opposite sides of the clearance groove along the Y-direction. Along the Y-direction, the distance between the groove wall and the electrode tab is B, where 2mm≤B≤5mm.

2. The battery cell according to claim 1, characterized in that, The first boss has an exhaust channel on the side facing the cover plate, and the exhaust channel passes through the first boss in the X direction.

3. The battery cell according to claim 2, characterized in that, Along the Y direction, the width of the exhaust channel is A, and the width of the electrode group is W, where 0.1 ≤ A / W ≤ 0.

15.

4. The battery cell according to claim 1, characterized in that, Along the Z direction, the third segment protrudes toward the first side relative to the first segment; The pole group has a second protrusion on the side facing the cover plate. On the projection plane perpendicular to the Z direction, the orthographic projection of the second protrusion is located within the orthographic projection of the third segment.

5. The battery cell according to claim 4, characterized in that, Along the Z direction, the height of the first boss is H1, satisfying 6mm ≤ H1 ≤ 7mm; and / or, Along the Z direction, the height of the second boss is H2, satisfying 3mm ≤ H2 ≤ 5mm; and / or, Along the Z direction, the height of the first boss is H1 and the height of the second boss is H2, satisfying 0.5≤H2 / H1≤0.

6.

6. The battery cell according to claim 4, characterized in that, The cover plate includes two second sections and two first sections. Along the X direction, the two second sections are connected to opposite sides of the third section, and the two first sections are respectively connected to the side of the two second sections away from the third section. The pole group is provided with two first protrusions. Along the X direction, the two first protrusions are connected to the opposite sides of the second protrusion. On the projection plane perpendicular to the Z direction, the orthographic projections of the two first protrusions are respectively located within the orthographic projections of the two second segments.

7. The battery cell according to claim 1, characterized in that, On a projection plane perpendicular to the Z direction, the orthographic projection of the tab lies within the orthographic projection of the first segment.

8. The battery cell according to claim 7, characterized in that, When the electrode tab extends along the Z direction, the height of the electrode tab along the Z direction is H3, satisfying 12.5mm ≤ H3 ≤ 15mm; and / or, 6mm≤a≤10mm.

9. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1-8.

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