A type of battery cell

Abstract

This utility model provides a battery cell, including a housing, an electrode assembly, a pressure relief mechanism, and a protective component. The housing has a first accommodating space and includes an end wall. The pressure relief mechanism is disposed on the end wall and is configured to open when the pressure inside the housing reaches a threshold. The protective component is housed within the first accommodating space and has a second accommodating space that communicates with the first accommodating space. The electrode assembly is housed within the second accommodating space. The protective component includes a first protective part located between the electrode assembly and the end wall. In the thickness direction of the end wall, the first protective part has a first surface and a second surface disposed opposite to each other. The first surface is closer to the end wall than the second surface. The first surface has an exhaust channel formed by a recess towards the second surface. The exhaust channel communicates with the first accommodating space and the pressure relief mechanism. The exhaust channel can effectively ensure the working reliability of the pressure relief mechanism.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell. Background Technology

[0002] In the development of battery technology, besides improving the performance of individual battery cells, safety is also a crucial issue that cannot be ignored. If the safety of individual battery cells cannot be guaranteed, then those cells cannot be used. Therefore, how to enhance the safety of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Utility Model Content

[0003] This utility model provides a battery cell to solve the technical problem that when the pressure relief mechanism is set on the end wall of the housing, the pressure relief mechanism cannot work reliably due to the obstruction of the electrode assembly, thereby affecting the safety of the battery cell.

[0004] This utility model provides a battery cell, the battery cell comprising: a housing having a first accommodating space, the housing including an end wall; a pressure relief mechanism disposed on the end wall, the pressure relief mechanism being configured to open when the pressure within the housing reaches a threshold; a protective member housed within the first accommodating space, the protective member having a second accommodating space communicating with the first accommodating space; and an electrode assembly housed within the second accommodating space, the protective member including a first protective portion located between the electrode assembly and the end wall, the first protective portion having a first surface and a second surface disposed opposite to each other in the thickness direction of the end wall, the first surface being closer to the end wall than the second surface, the first surface having an exhaust channel formed by a recess toward the second surface, the exhaust channel communicating with the first accommodating space and the pressure relief mechanism.

[0005] In one embodiment of the present invention, the housing further includes a sidewall connected to the periphery of the end wall, and the protective member further includes a second protective part located between the electrode assembly and the sidewall. An exhaust gap is formed between the sidewall and the second protective part, and the end of the exhaust channel extends to the edge of the first surface near the exhaust gap, so that the exhaust channel communicates with the exhaust gap and the pressure relief mechanism.

[0006] In one embodiment of the present invention, the first protective part includes a clearance area. Along the thickness direction of the end wall, the pressure relief mechanism is located within the orthographic projection of the clearance area on the end wall. The clearance area is formed by the first surface being recessed towards the second surface. The clearance area is connected to the exhaust channel and the pressure relief mechanism.

[0007] In one embodiment of this utility model, the area of ​​the void relief zone projected onto the end wall is S1, and the area of ​​the pressure relief mechanism is S2, where 1≤S1 / S2≤2.

[0008] In one embodiment of the present invention, in the thickness direction of the end wall, the maximum thickness of the first protective part is H1, and the clearance area is formed by the first surface being recessed into the second surface to a predetermined depth, the predetermined depth being H2, 0.3≤H2 / H1≤0.8; and / or, 0.2mm≤H2≤1mm.

[0009] In one embodiment of the present invention, the first protective part includes a buffer groove, which is formed by the second surface recessing into the first surface. At least a portion of the exhaust channel is misaligned with the buffer groove in a preset direction, and the preset direction is perpendicular to the thickness direction of the end wall.

[0010] In one embodiment of the present invention, the area of ​​the first surface is S3, the exhaust channel includes a bottom wall opposite to the end wall, the area of ​​the bottom wall is S4, 0.4≤S4 / S3≤0.7; and / or, the area of ​​the second surface is S5, the buffer groove includes a groove bottom near the end wall, the area of ​​the groove bottom is S6, 0.4≤S6 / S5≤0.7.

[0011] In one embodiment of this utility model, the electrode assembly is connected to a tab, and in the thickness direction of the end wall, the maximum thickness H1 of the first protective portion and the mass M of the electrode assembly satisfy the following:

[0012] When 0 < M ≤ 0.8 kg, 0.3 mm ≤ H1 ≤ 0.5 mm;

[0013] When 0.8kg < M ≤ 2.2kg, 0.5mm < H1 ≤ 1.5mm;

[0014] When M > 2.2 kg, H1 > 1.5 mm.

[0015] In one embodiment of the present invention, the exhaust channel includes multiple first exhaust channels extending along the length direction of the end wall. In the width direction of the end wall, the size of the first protective part is W1, and the maximum size of the first exhaust channel is W2, 0.05≤W2 / W1≤0.1; and / or, the exhaust channel includes multiple second exhaust channels extending along the width direction of the end wall. In the width direction of the end wall, the size of the first protective part is L, and the maximum size of the second exhaust channel is W3, 0.01≤W3 / L≤0.05.

[0016] In one embodiment of the present invention, the electrode assembly includes an electrode sheet, the electrode sheet includes a straight portion extending along a first direction, the exhaust channel extends along a second direction, the first direction and the second direction are both perpendicular to the thickness direction of the end wall, and the first direction and the second direction are arranged at an angle.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] In the event of thermal runaway, the venting channel provides a direct and unobstructed path for high-pressure gas and high-temperature substances inside the casing to the pressure relief mechanism, ensuring that it can open normally and quickly relieve pressure when the pressure reaches the threshold. This prevents casing tearing or module-level thermal runaway caused by electrode assembly obstruction, thereby significantly improving the safety and reliability of the battery cell. The venting channel is formed directly by recessing it into the surface of the first protective part, eliminating the need for folded protective parts or additional auxiliary structures to maintain the channel shape. This simplifies the processing and assembly of the protective parts, improving production efficiency and product consistency. The first protective part also serves as a support and insulation component, further enhancing the reliability of the pressure relief mechanism. Simultaneously, it can also provide support for the electrode assembly, eliminating the need for additional support structures between the electrode assembly and the end wall. This reduces the number of components inside the battery cell, saving material costs and reducing the quality risks that may arise from assembling multiple components. By guiding the discharge of internal substances through standardized venting channels, it reduces the direct squeezing or impact of the electrode assembly on the pressure relief mechanism under harsh operating conditions, lowers the risk of accidental opening of the explosion-proof valve, and further ensures the stability of the battery in complex operating environments. In addition, the venting channels can slightly reduce the strength of the first protective part, making it more prone to deformation, which can play a protective and buffering role for the electrode assembly. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] In the attached diagram:

[0021] Figure 1 A schematic diagram showing the unfolded components of a battery cell according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the end wall of a battery cell provided in one embodiment of the present invention;

[0023] Figure 3 for Figure 2The diagram shows a cross-sectional view of a battery cell including a second exhaust channel in the AA direction.

[0024] Figure 4 for Figure 3 A magnified view of a portion of Part B;

[0025] Figure 5 for Figure 2 The diagram shows a cross-sectional view of a battery cell, including the first exhaust channel, in the AA direction.

[0026] Figure 6 for Figure 5 A magnified view of a portion of section C;

[0027] Figure 7 A cross-sectional view of a protective component provided in an embodiment of this utility model;

[0028] Figure 8 A schematic diagram of the first protective part provided in an embodiment of the present invention;

[0029] Figure 9 A schematic diagram of the first protective part provided in another embodiment of the present invention;

[0030] Figure 10 A schematic diagram of the first protective part provided in another embodiment of the present invention;

[0031] Figure 11 for Figure 10 Sectional view in the DD direction;

[0032] Figure 12 A partial electrode assembly including a flat portion of the electrode sheet is provided as an embodiment of the present invention.

[0033] The attached figures are labeled as follows:

[0034] 100, Housing; 110, End wall; 120, Side wall; 200, Electrode assembly; 210, Electrode sheet; 211, Straight section; 220, Diaphragm; 300, Pressure relief mechanism; 400, Protective component; 410, First protective section; 411, First surface; 412, Second surface; 420, Second protective section; 500, Exhaust channel; 510, First exhaust channel; 520, Second exhaust channel; 600, Clearance area; 700, Exhaust gap; 800, Buffer groove; 900, Cover plate; 1000, Tab; X, First direction; Y, Second direction. Detailed Implementation

[0035] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0036] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0037] As consumers become increasingly concerned about the safety of lithium batteries, the new national standard for batteries has set higher and higher requirements for the safety technology of power batteries. The new regulations take preventing fires and explosions as the core objective. The inventors discovered that if the pressure relief mechanism of the battery cell terminal and the explosion-proof valve are both located on the cover plate, when the battery cell runs out of control, the material ejected by the pressure relief mechanism may affect the terminal and the surrounding high and low voltage wiring harness. Therefore, in order to improve safety, a design scheme can be adopted to place the pressure relief mechanism at the bottom of the shell opposite to the cover plate, so as to separate the terminal and the pressure relief mechanism and achieve thermoelectric separation.

[0038] However, the above design introduces new problems. Because the pressure relief mechanism is located at the bottom of the casing, it is completely blocked by the electrode components pressing above it. When a single battery cell experiences thermal runaway, an effective venting path cannot be formed, leading to casing tearing and further thermal runaway at the module and battery pack levels. Furthermore, placing the pressure relief mechanism at the bottom of the casing means that under harsh operating conditions, the internal electrode components of the battery cell may compress the pressure relief structure, affecting its function and causing the explosion-proof valve to open abnormally. In the manufacturing process of lithium batteries, to ensure insulation between the electrode components and the casing, a protective layer with good insulation, high-temperature resistance, and a certain mechanical strength is applied to the outer surface of the electrode components. This protective layer is typically made of Mylar film, such as PET or PC, and a base plate is placed between the bottom wall of the casing and the Mylar film to support the electrode components and enhance insulation.

[0039] This invention features an exhaust channel on the first protective part of the protective component, located between the electrode assembly and the bottom wall of the housing, connecting the pressure relief mechanism and the housing space. This allows for the smooth transmission of internal pressure to the pressure relief mechanism when the battery cell experiences overheating and runaway. This ensures the pressure relief mechanism can open normally while simultaneously guiding gas from the housing to the mechanism for discharge, thus improving the safety of the battery cell. Furthermore, the exhaust channel is directly formed at the bottom of the protective component, eliminating the need to fold the protective component or use other structures to restrict its shape and maintain unobstructed flow. This simplifies the assembly structure of the protective component. Additionally, the first protective part can integrate a bottom support plate into the protective component, eliminating the need for a bottom support plate in the battery cell and improving production efficiency.

[0040] The technical solution of this utility model will be described in detail below with reference to specific embodiments:

[0041] Please see Figures 1-11The battery cell provided by this utility model includes a housing 100, an electrode assembly 200, a pressure relief mechanism 300, and a protective component 400. The housing 100 has a first accommodating space and includes an end wall 110. The pressure relief mechanism 300 is disposed on the end wall 110 and is configured to open when the pressure inside the housing 100 reaches a threshold. Specifically, the pressure relief mechanism 300 can be configured as an explosion-proof valve. The explosion-proof valve includes an explosion-proof hole extending along the thickness direction of the end wall 110 and an explosion-proof plate installed in the explosion-proof hole. When the internal pressure of the battery cell reaches the threshold, the explosion-proof plate can open, and the internal pressure of the battery cell is released through the explosion-proof hole. The protective member 400 is housed within a first receiving space. The protective member 400 also has a second receiving space, which is connected to the first receiving space. The electrode assembly 200 is housed within the second receiving space. In some embodiments, the protective member 400 covers the bottom surface of the electrode assembly 200 opposite to the end wall 110 and the side surface connected to the periphery of the bottom surface. The top surface of the electrode assembly 200 opposite to the bottom surface is not covered and has an opening. In this case, the first and second receiving spaces are connected through the opening. In other embodiments, the protective member 400 has an overlapping area on the aforementioned side surface of the electrode assembly 200. The overlapping area is formed by at least two layers of protective members 400 stacked together. The protective members 400 are fixedly connected at a portion of the overlapping area by adhesive, hot-melt, or bonding methods. In the unfixed portions, gaps can be formed between the multiple layers of protective members 400 in the overlapping area, allowing the first and second receiving spaces to communicate. The protective member 400 includes a first protective portion 410 located between the electrode assembly 200 and the end wall 110. In the thickness direction of the end wall 110, the first protective portion 410 has a first surface 411 and a second surface 412 disposed opposite to each other. The first surface 411 is closer to the end wall 110 than the second surface 412. The first surface 411 has an exhaust channel 500 formed by a recess towards the second surface 412. The exhaust channel 500 connects the first receiving space and the pressure relief mechanism 300. Specifically, the exhaust channel 500 can be configured as follows: Figure 8 The one or more grooves provided along the width direction of the first protective portion 410, as shown, can also be configured as follows: Figure 9 The one or more grooves shown, which are provided along the length of the first protective part 410, can also be configured as follows: Figure 1 , Figure 9 The grooves shown include one or more grooves along the length of the first protective portion 410, and also include one or more grooves along the width of the first protective portion 410. They can also be configured as other curved grooves.

[0042] In the event of thermal runaway, the exhaust channel 500 provides a direct and unobstructed path for high-pressure gas and high-temperature substances inside the housing 100 to the pressure relief mechanism 300. This ensures that the pressure relief mechanism 300 can open normally and quickly relieve pressure when the pressure reaches the threshold, preventing high-pressure gas and high-temperature substances from being blocked by the electrode assembly 200, which could cause the housing 100 to tear or trigger module-level thermal runaway. This significantly improves the safety and reliability of the battery cell. The exhaust channel 500 is formed directly by recessing from the first surface 411 to the second surface 412, without relying on a folded protective film or additional auxiliary structures to maintain the channel shape. This simplifies the processing and assembly process of the protective component 400, and helps improve production efficiency and product consistency. For example, the exhaust channel 500 can be formed by recessing on the first surface 411. Specifically, the groove can be formed by cutting, stamping, or molding, or it can be directly formed by molding to create a grooved protective component 400. In other words, the exhaust channel 500 and the protective component 400 are integrally formed. The first protection unit 410 serves both support and insulation functions, replacing the original base plate structure and reducing the number of independent components inside the battery cell. This not only saves material costs but also reduces the quality risks that may arise from the assembly of multiple components. The standardized exhaust channel 500 guides the discharge of internal substances, reducing the direct squeezing or impact of the electrode assembly 200 on the pressure relief mechanism 300 under harsh working conditions. This also reduces the risk of accidental opening of the explosion-proof valve, further ensuring the stability of the battery cell in complex operating environments. In addition, the exhaust channel 500 also allows the first protection unit 410 to act as a protective buffer for the electrode assembly 200.

[0043] Please see Figures 3-6 In an optional embodiment of this utility model, the housing 100 further includes a sidewall 120 connected to the periphery of the end wall 110, and the protective member 400 further includes a second protective part 420, which is located between the electrode assembly 200 and the sidewall 120. The second protective part 420 is connected to the periphery of the first protective part 410. For example, the second protective part 420 can be integrally formed with the first protective part 410. There is an exhaust gap 700 between the sidewall 120 and the second protective part 420. The end of the exhaust channel 500 extends to the first surface 411 near the edge of the exhaust gap 700, so that the exhaust channel 500 communicates with the exhaust gap 700 and the pressure relief mechanism 300. Specifically, when the exhaust gap 700 is located between the two sidewalls 120 that are respectively connected to the two long sides of the end wall 110 (i.e., with the two long sides of the end wall 110), the exhaust gap 700 is connected to the two sidewalls 120 that are respectively connected to the two long sides of the end wall 110. Figure 1 When the exhaust passage 500 is located between the two side walls parallel to the first direction X and the second protective part 420, the exhaust passage 500 can be configured as follows: Figure 3 , Figure 4The one or more grooves extending along the width direction of the first protective portion 410 (e.g., in the form of a second exhaust channel 520) are shown when the exhaust gap 700 is located on the side wall 120 connected to the two short sides of the end wall 110 (i.e., with...). Figure 1 When the two side walls parallel to the second direction Y) are between the second protective part 420, the exhaust channel 500 can be set as follows: Figure 5 , Figure 6 The groove (e.g., in the form of a first exhaust channel 510) extending along the length of the first protective portion 410 is shown. In some embodiments, when placing the electrode assembly 200, a mounting gap is generally reserved between the side wall 120 connected to the two short sides of the end wall 110 and the second protective portion 420. Therefore, it is preferable to configure the exhaust channel 500 as shown. Figure 5 , Figure 6 The structure shown eliminates the need to create additional gaps by reducing the size of the electrode assembly 200 or the thickness of the housing 100, thus avoiding excessive space occupation of the housing 100 by the exhaust gap 700 and maximizing the energy density of the battery cell.

[0044] When the electrode assembly 200 experiences thermal runaway, generating high-temperature, high-pressure gas, this gas can first flow into the first protection section 410 through the exhaust gap 700, and then flow to the pressure relief mechanism 300 through the exhaust channel 500 provided on the first protection section 410. Furthermore, please refer to... Figure 6 In some embodiments, since the second protective part 420 and the electrode assembly 200 are not tightly fitted together, and the protective part 400 is not covered on the top surface of the electrode assembly 200 opposite to the cover plate 900, the high-temperature and high-pressure gas generated on the side of the electrode assembly 200 can first flow upward through the space between the electrode assembly 200 and the second protective part 420 to the cover plate 900. Then it flows downward through the exhaust gap 700 to the first protective part 410, and finally flows into the pressure relief mechanism 300 through the exhaust channel 500 and is discharged from the housing 100.

[0045] The presence of the exhaust gap 700 prevents the electrode assembly 200 from directly squeezing or blocking the inlet of the exhaust channel 500 due to expansion or displacement during manufacturing or long-term use. This allows the high-temperature and high-pressure gas inside the housing 100 to reach the pressure relief mechanism 300 in an orderly, uniform, and rapid manner, ensuring exhaust efficiency and the unobstructed and long-term stability of the exhaust channel 500. This enables the pressure relief mechanism 300 to reliably receive the actual internal pressure signal of the housing 100 and open in a timely manner, thereby further improving the safety of the battery cell.

[0046] Please see Figure 1 , Figure 10 , Figure 11In an optional embodiment of the present invention, the first protective part 410 includes a relief area 600. Along the thickness direction of the end wall 110, the pressure relief mechanism 300 is located within the orthographic projection of the relief area 600 on the end wall 110. The relief area 600 is formed by the recess from the first surface 411 to the second surface 412. The relief area 600 is connected to the exhaust channel 500 and the pressure relief mechanism 300.

[0047] The clearance zone 600 ensures a gap between the pressure relief mechanism 300 and the protective element 400, allowing the high-temperature, high-pressure gas flowing into this area through the exhaust channel 500 to smoothly enter the pressure relief mechanism 300. Furthermore, the clearance zone 600 further ensures that even under severe operating conditions where the electrode assembly 200 expands significantly, and the first protective element 410 is deformed by the pressure of the electrode assembly 200, the pressure relief mechanism 300 itself will not be directly compressed by the first protective element 410. This prevents abnormal opening or damage to the pressure relief mechanism 300 due to physical compression when the internal pressure of the housing 100 reaches a threshold. Specifically, to further ensure the operational reliability of the clearance zone 600, the recess depth of the clearance zone 600 can be set to be greater than the recess depth of the exhaust channel 500. In some embodiments, along the thickness direction of the end wall 110, the outer contour of the clearance zone 600 projected onto the end wall 110 can be similar to that of the pressure relief mechanism 300, for example, both being elliptical, rectangular, or "H"-shaped, and the area enclosed by the outer contour is the aforementioned projected shape.

[0048] Please refer to 1. In an optional embodiment of this utility model, along the thickness direction of the end wall 110, the orthogonal projection area of ​​the clearance zone 600 on the end wall 110 is S1, and the area of ​​the pressure relief mechanism 300 is S2, where 1≤S1 / S2≤2.

[0049] The above design ensures that the projected area of ​​the relief zone 600 at least completely covers the pressure relief mechanism 300. This ensures that the entire effective working surface of the pressure relief mechanism 300 is within the unobstructed relief zone 600, allowing pressure to be applied evenly and fully, guaranteeing its smooth opening as designed. If S1 / S2 < 1, it means that a portion of the pressure relief mechanism 300 may be obstructed, leading to poor opening, irregular breakage, or unstable opening pressure values. Since the first protective part 410 is an insulating and protective structural component, it needs a certain structural strength to support the upper electrode assembly 200 and resist internal pressure. The above design can avoid the excessively large clearance area 600 from significantly weakening the mechanical strength of the first protective part 410, causing it to collapse under normal working conditions or rupture prematurely during thermal runaway, interfering with the pressure relief process. Specifically, it can be set to S1 / S2 = 1 or S1 / S2 = 1.1 or S1 / S2 = 1.3 or S1 / S2 = 1.5 or S1 / S2 = 2, or set to 1≤S1 / S2≤1.5, or further set to 1.1≤S1 / S2≤1.3.

[0050] Please see Figure 10 , Figure 11 In an optional embodiment of this utility model, in the thickness direction of the end wall 110, the maximum thickness of the first protective part 410 is H1, and the clearance area 600 is formed by recessing a preset depth from the first surface 411 to the second surface 412, the preset depth being H2. Specifically, H1 and H2 can be set to satisfy the following conditions: 0.3≤H2 / H1≤0.8 or 0.2mm≤H2≤1mm or 0.3≤H2 / H1≤0.8 and 0.2mm≤H2≤1mm.

[0051] The lower limit setting of H2 / H1≥0.3 or H2≥0.2mm can ensure that the air-proof zone 600 has sufficient depth, thereby ensuring exhaust efficiency. The upper limit setting of H2 / H1≤0.8 or H2≤1mm can further ensure the mechanical strength of the first protective part 410, so that the first protective part 410 will not be excessively deformed or even broken due to excessive weakening of strength.

[0052] Please see Figure 3 , Figure 4 , Figure 7 In an optional embodiment of the present invention, the first protective part 410 includes a buffer groove 800, which is formed by the second surface 412 recessed towards the first surface 411. In a preset direction, at least a portion of the exhaust channel 500 is misaligned with the buffer groove 800. The preset direction is a direction perpendicular to the thickness direction of the end wall 110. Specifically, both the buffer groove 800 and the exhaust channel 500 can be configured as multiple grooves to form multiple "Z"-shaped structures on the first protective part 410. This allows the first protective part 410 to release the impact of internal components such as the electrode assembly 200 on the pressure relief mechanism 300 by the deformation of the buffer groove 800 and the exhaust channel 500 when subjected to a force along its thickness direction (such as vibration or impact that may occur when the battery cell is in use). This prevents the pressure relief mechanism 300 from being accidentally opened, and at least a portion of the exhaust channel 500 and the buffer groove 800 are misaligned in the preset direction. In some embodiments, in the thickness direction of the end wall 110, the projection of one of the exhaust channel 500 and the buffer groove 800 will not fall completely into the projection of the other, thereby excessively weakening the structural strength of the first protective part 410 of the overlapping part of the two. This is beneficial to maintain the shape of the exhaust channel 500 and the buffer groove 800, ensuring unobstructed air passage during depressurization and reliable coverage of the electrode assembly 200 by the protective member 400.

[0053] To further ensure the structural strength of the first protective part 410, the exhaust channel 500 and the buffer groove 800 can be completely misaligned in a preset direction.

[0054] Please see Figure 4 , Figure 9 In an optional embodiment of this utility model, the area of ​​the first surface 411 is S3, the exhaust channel 500 includes a bottom wall opposite to the end wall 110, the area of ​​the bottom wall is S4, the area of ​​the second surface 412 is S5, and the buffer groove 800 includes a groove bottom near the end wall 110, the area of ​​the groove bottom is S6. Specifically, S3, S4, S5, and S6 can be designed to satisfy the following conditions: 0.4≤S4 / S3≤0.7 or 0.4≤S6 / S5≤0.7 or 0.4≤S4 / S3≤0.7 and 0.4≤S6 / S5≤0.7. Specifically, S4 / S3=0.5 or S6 / S5=0.5 or S4 / S3=0.5 and S6 / S5=0.5. The area ratio within the above parameter range can well balance the exhaust efficiency, support strength, and buffer function of the first protective member 400.

[0055] In an optional embodiment of this utility model, the electrode assembly 200 is connected to a tab 1000, and in the thickness direction of the end wall 110, the maximum thickness H1 of the first protective part 410 and the mass M of the electrode assembly 200 satisfy the following:

[0056] When 0 < M ≤ 0.8 kg, 0.3 mm ≤ H1 ≤ 0.5 mm;

[0057] When 0.8kg < M ≤ 2.2kg, 0.5mm < H1 ≤ 1.5mm;

[0058] When M > 2.2 kg, H1 > 1.5 mm.

[0059] It should be noted that the electrode assembly 200 includes an electrode 210 and a separator 220. The electrode 210 includes a positive electrode and a negative electrode. The separator 220 is disposed between the electrodes 210 to separate adjacent positive and negative electrodes. In some embodiments, the battery cell also includes a tab 1000 connected to the electrode assembly 200. The tab 1000 is led out from the positive and negative electrodes. Specifically, the areas on the positive and negative electrodes that are not coated with active material extend out to form the tab 1000.

[0060] In some embodiments, the tabs can be connected to the side of the electrode assembly 200 away from the end wall 110. The mass of the electrode assembly 200 refers to the mass of the electrode assembly 200 composed of the positive electrode, negative electrode, and separator, excluding the mass of the tabs connected to the positive and negative electrode plates. The thickness of the first protective portion 410 is set according to different mass ranges of the electrode assembly 200, ensuring sufficient support strength for the first protective portion 410 to guarantee the stability of the exhaust channel 500. It also avoids the first protective portion 410 being too thick and encroaching on the space of the electrode assembly 200, thus ensuring the energy density of the battery cell and minimizing the impact of the first protective portion 400 on the mass of the battery cell. Here, the mass M is the mass of the electrode assembly 200 at 0% SOC (state of charge). Specifically, the battery cell can be discharged to 0% SOC at its rated current, and then the electrode assembly 200 can be separated and weighed to calculate its mass. The electrode assembly 200 in a single battery cell may be composed of multiple wound bodies or stacked bodies. In this case, the mass M of the electrode assembly 200 is the sum of the masses of all wound bodies or stacked bodies.

[0061] Please see Figures 8-11 In an optional embodiment of this utility model, multiple first exhaust channels 510 extending along the length direction of the end wall 110 can be formed on the first surface 411. In the width direction of the end wall 110, the size of the first protective part 410 is W1, and the maximum size of the first exhaust channel 510 is W2. Specifically, W1 and W2 can be designed to satisfy the following condition: 0.05≤W2 / W1≤0.1. Alternatively, multiple second exhaust channels 520 extending along the width direction of the end wall 110 can be formed on the first surface 411. In the width direction of the end wall 110, the size of the first protective part 410 is L, and the maximum size of the second exhaust channel 520 is W3. Specifically, L and W3 can be designed to satisfy the following condition: 0.01≤W3 / L≤0.05. Alternatively, multiple first exhaust channels 510 and multiple second exhaust channels 520 can be formed on the first surface 411. It should be noted that when there are first exhaust channels 510 or second exhaust channels 520 with different widths on the first protection part 410, the maximum size W2 or W3 refers to the width of the exhaust channel with the largest width in the corresponding direction.

[0062] An excessively narrow exhaust channel 500 will generate too much resistance to high-temperature and high-pressure gas, which is not conducive to improving exhaust efficiency; while an excessively wide single exhaust channel 500 may cause the strength of the first protective part 410 to be significantly reduced at this point, which may lead to excessive deformation or even cracking, affecting insulation performance.

[0063] Please see Figure 12In an optional embodiment of this utility model, the electrode assembly 200 includes an electrode sheet 210. Specifically, the electrode sheet 210 includes a positive electrode sheet and a negative electrode sheet, and a separator 220 separating the positive and negative electrode sheets. The electrode sheet 210 includes a straight portion 211 extending along a first direction X. Specifically, the electrode assembly 200 can be a coiled body with a straight structure in the middle and rounded structures at both ends, or it can be a stacked body that is generally rectangular in shape. The exhaust channel 500 extends along a second direction Y. Both the first direction X and the second direction Y are perpendicular to the thickness direction of the end wall 110, and the first direction X and the second direction Y are set at an angle. It is understood that the second direction Y is not unique; any direction that is set at an angle to the first direction X can be the second direction Y. For example, the orthographic projection of the exhaust channel 500 on the end wall 110 can be one or more "X" shapes, etc.

[0064] The above design effectively prevents the electrode located above the exhaust channel from easily sinking into the corresponding recessed position of the exhaust channel when the first and second directions are parallel. This can lead to misalignment between the electrode and other electrodes, causing a short circuit, or increased spacing between electrodes of different polarities, resulting in lithium plating. Furthermore, misalignment can even cause direct contact between the positive and negative electrodes, leading to a short circuit. Preferably, the first direction X and the second direction Y can be set to be perpendicular to each other.

[0065] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A battery cell, characterized by, include: A housing having a first receiving space, the housing including end walls; A pressure relief mechanism is disposed on the end wall and is configured to open when the pressure inside the housing reaches a threshold. A protective component, wherein the protective component is housed within the first accommodating space, and the protective component has a second accommodating space, the second accommodating space being connected to the first accommodating space; An electrode assembly is housed within a second receiving space. The protective member includes a first protective portion located between the electrode assembly and the end wall. In the thickness direction of the end wall, the first protective portion has a first surface and a second surface disposed opposite to each other. The first surface is closer to the end wall than the second surface. The first surface has an exhaust channel formed by recessing towards the second surface. The exhaust channel communicates with the first receiving space and the pressure relief mechanism.

2. The battery cell according to claim 1, characterized in that, The housing further includes a sidewall connected to the periphery of the end wall, and the protective member further includes a second protective portion located between the electrode assembly and the sidewall. An exhaust gap is provided between the sidewall and the second protective portion, and the end of the exhaust channel extends to the edge of the first surface near the exhaust gap, so that the exhaust channel communicates with the exhaust gap and the pressure relief mechanism.

3. The battery cell according to claim 1, characterized in that, The first protective part includes a relief zone along the thickness direction of the end wall. The pressure relief mechanism is located within the orthographic projection of the relief zone on the end wall. The relief zone is formed by the first surface being recessed into the second surface. The relief zone is connected to the exhaust channel and the pressure relief mechanism.

4. The battery cell according to claim 3, characterized in that, The area of ​​the air-relief zone projected onto the end wall is S1, and the area of ​​the pressure relief mechanism is S2, where 1 ≤ S1 / S2 ≤ 2.

5. The battery cell according to claim 3, characterized in that, In the thickness direction of the end wall, the maximum thickness of the first protective part is H1, and the clearance area is formed by the first surface being recessed into the second surface to a predetermined depth, the predetermined depth being H2, 0.3≤H2 / H1≤0.8; and / or, 0.2mm≤H2≤1mm.

6. The battery cell according to claim 1, characterized in that, The first protective part includes a buffer groove, which is formed by the second surface recessing into the first surface. At least a portion of the exhaust channel is misaligned with the buffer groove in a preset direction, which is perpendicular to the thickness direction of the end wall.

7. The battery cell according to claim 6, characterized in that, Along the thickness direction of the end wall, the area of ​​the first surface is S3, the exhaust channel includes a bottom wall opposite to the end wall, the area of ​​the bottom wall is S4, 0.4≤S4 / S3≤0.7; and / or, the area of ​​the second surface is S5, the buffer groove includes a groove bottom near the end wall, the area of ​​the groove bottom is S6, 0.4≤S6 / S5≤0.

7.

8. The battery cell according to claim 1, characterized in that, The electrode assembly is connected to a tab, and in the thickness direction of the end wall, the maximum thickness H1 of the first protective portion and the mass M of the electrode assembly satisfy the following: When 0 < M ≤ 0.8 kg, 0.3 mm ≤ H1 ≤ 0.5 mm; When 0.8kg < M ≤ 2.2kg, 0.5mm < H1 ≤ 1.5mm; When M > 2.2 kg, H1 > 1.5 mm.

9. The battery cell according to claim 1, characterized in that, The exhaust channel includes multiple first exhaust channels extending along the length direction of the end wall. In the width direction of the end wall, the size of the first protective part is W1, and the maximum size of the first exhaust channel is W2, 0.05≤W2 / W1≤0.1; and / or, the exhaust channel includes multiple second exhaust channels extending along the width direction of the end wall. In the width direction of the end wall, the size of the first protective part is L, and the maximum size of the second exhaust channel is W3, 0.01≤W3 / L≤0.

05.

10. The battery cell according to claim 1, characterized in that, The electrode assembly includes an electrode sheet, the electrode sheet including a straight portion extending along a first direction, the exhaust channel extending along a second direction, both the first direction and the second direction being perpendicular to the thickness direction of the end wall, and the first direction and the second direction being set at an angle.

Images