Battery cell, battery pack, and electric device

Abstract

The application relates to the new energy technology field and discloses a battery monomer, a battery pack and a power utilization device. The battery monomer comprises: a battery core; a shell assembly; a shell body comprising a first shell part and a second shell part along a first direction, the thickness E of the first shell part is greater than the thickness of the second shell part; an insulating part arranged between a cover plate and the battery core along the first direction, the minimum interval distance between the insulating part and the inner side wall of the shell body is D mm; the cover plate and the shell body are welded and connected in the region close to the opening part to form a first welding line, the maximum size of the first welding line along the first direction is A mm; and the following formula is satisfied: 0.032 <= (A*E) / D <= 12. The battery monomer provided by the application limits the upper limit of the formula value, suppresses the risk of heat damage of the insulating part, ensures that the welding seam has sufficient strength, limits the lower limit of the formula value, guarantees the welding reliability between the cover plate and the shell body, and guarantees the assembly space utilization rate of the battery core in the shell assembly.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a battery cell, a battery pack, and an electrical device. Background Technology

[0002] To ensure insulation between the battery cover and the battery cell, related technologies will set an insulating component between the battery cover and the battery cell. However, when the cover is welded to the casing, the insulating component is prone to melting due to the welding heat, which increases the risk of short circuit between the battery cell and the cover. Summary of the Invention

[0003] In view of this, the present invention provides a battery cell, a battery pack, and an electrical device to solve the problem that the risk of short circuit between the battery cell and the cover plate is increased due to the easy melting of the insulating parts by welding heat.

[0004] In a first aspect, the present invention provides a battery cell, comprising: The housing assembly includes a housing body and a cover plate. The housing body has an opening at at least one end along a first direction, and the cover plate seals the opening. The housing body includes a first housing portion and a second housing portion along the first direction. The first housing portion is located closer to the opening than the second housing portion, and the thickness of the first housing portion is greater than the thickness of the second housing portion. The thickness of the first housing portion is E mm. The battery cell is located inside the housing assembly; An insulating component is disposed between the cover plate and the battery cell along the first direction, and the minimum distance between the insulating component and the inner wall of the housing body is D mm. The cover plate and the shell body are welded together in the area near the opening to form a first weld line, and the maximum dimension of the first weld line along the first direction is A mm; It satisfies: 0.032≤(A×E) / D≤12.

[0005] Beneficial effects: Since the insulating component is located under the cover plate, the risk of melting of the insulating component gradually increases with the increase of the welding depth of the first weld line. By precisely controlling the synergistic relationship between E mm, A mm, and D mm, when the formula value of (A×E) / D is too large, it indicates that the proportion of A or E is too large, which means that the welding heat input is too strong and the risk of heat damage to the insulating component is increased. Alternatively, if the proportion of D is too small, the distance between the insulating component and the shell body is too narrow. Even if the welding heat input is not significantly increased, the insulating component is still prone to overheating due to the shortened heat conduction path, which increases the risk of heat damage to the insulating component and may lead to a short circuit between the cover plate and the battery cell, posing a significant safety risk. Conversely, when the value of (A×E) / D is too small, the proportion of A or E is too small, indicating insufficient welding heat input, limited weld penetration and width, reduced welding dimensions between the cover plate and the shell body, low connection strength, increased risk of cracking at the weld line, and easy detachment of the cover plate as a whole. Alternatively, if the proportion of D is too large, the cell installation space will be limited, and the battery energy density will decrease.

[0006] By limiting the upper limit of the formula (A×E) / D, the risk of heat damage to the insulation components can be effectively suppressed, while ensuring that the weld has sufficient strength. By limiting the lower limit of the formula (A×E) / D, the reliability of the welding between the cover plate and the shell body can be guaranteed, and the utilization rate of the assembly space of the battery cell in the shell assembly can be guaranteed.

[0007] Secondly, the present invention also provides a battery pack, comprising: Multiple battery cells as described above are stacked along a second direction, which is perpendicular to the large side surface of the battery cell, where the large side surface is the largest area surface of the battery cell.

[0008] Since the battery pack includes individual battery cells and has the same effect as individual battery cells, it will not be elaborated on here.

[0009] Thirdly, the present invention also provides an electrical device, comprising: The electrical device body and the battery pack as described above, which is electrically connected to the electrical device body.

[0010] Since the electrical device includes individual battery cells and has the same effect as individual battery cells, it will not be elaborated further here. Attached Figure Description

[0011] 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.

[0012] Figure 1 This is an exploded view of the battery cell of the present invention; Figure 2 This is a top view of a single battery cell of the present invention; Figure 3 for Figure 2 Schematic diagram of section AA; Figure 4 for Figure 3 A magnified view of a portion of the image; Figure 5 for Figure 3 A further magnified view of the relevant area; Figure 6 This is a partially enlarged view of the cross-section of the battery cell of the present invention after removing the cell and the casing. Figure 7 This is a partially enlarged view of the cover plate of the present invention having a chamfered portion.

[0013] Explanation of reference numerals in the attached figures: 10. Shell assembly; 1. Shell body; 11. Opening; 12. First shell section; 121. Equal thickness region; 122. Non-equal thickness region; 13. Second shell section; 101. First shell wall; 102. Second shell wall; 2. Cover plate; 21. First cover plate surface; 22. Main body; 23. Boss portion; 231. Boss sidewall; 232. Chamfered portion; 3. First bonding wire; 4. Battery cell; 41. Battery cell body; 42. Terminal tab; 5. Insulating component; 51. Insulating component body; 52. Flange structure; 6. Pole post assembly. Detailed Implementation

[0014] 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.

[0015] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] To ensure insulation between the battery cover and the battery cell, related technologies will set an insulating component between the battery cover and the battery cell. However, when the cover is welded to the casing, the insulating component is prone to melting due to the welding heat, which increases the risk of short circuit between the battery cell and the cover.

[0019] To improve the connection strength between the cover plate and the housing and prevent cracking at the weld line, the area near the opening of the housing is thickened to increase the welding dimensions between the housing and the cover plate, thereby improving the connection strength between the cover plate and the housing.

[0020] However, research has found that the main reason for the melting of the insulation is that the thickening of the shell leads to an increase in welding power and a sharp rise in welding heat. During the welding process, the insulation located under the cover plate is affected by the heat and melts. Furthermore, the larger the welding size and the size of the thickened area, the greater the welding power required, resulting in a more severe degree of melting of the insulation. This increases the risk of short circuit between the cell and the shell, affecting the overall safety of the battery.

[0021] To solve the above-mentioned technical problems, the battery cell provided in this application reduces the impact of welding heat on the insulating components by reasonably controlling the relationship between the design parameters of the casing and the welding process parameters, while ensuring the welding strength between the cover plate and the casing, thereby ensuring the insulation performance and structural safety of the battery cell.

[0022] To facilitate understanding of the technical solution of this application, several technical terms that may be involved in this application will first be explained: The housing assembly 10, also known as the housing, is a component used to provide a receiving space to house the electrode assembly and other parts and isolate them from the outside environment. The housing generally includes a body with an opening at at least one end and a receiving cavity. The opening of the housing can be closed by a cover plate to seal and isolate the internal environment of the battery cell from the external environment. The materials of the housing include, but are not limited to, copper, iron, aluminum, stainless steel, and aluminum alloy.

[0023] Cover plate 2 is a component that seals the opening of the casing to isolate the internal environment of the battery cell from the external environment. The cover plate is made of materials including but not limited to copper, iron, aluminum, stainless steel, and aluminum alloy.

[0024] Cell 4 is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of performing electrochemical reactions such as charging / discharging. A cell is the basic unit of a battery and typically includes a positive electrode, a negative electrode, and a separator. Lithium-ion cells primarily function by the movement of lithium ions between the positive and negative electrodes. In cylindrical cells, the three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0025] Insulating component 5 is disposed between the terminal post and the lower surface of the battery casing body. It is used to insulate the terminal post (electrode terminal) from the lower surface (or bottom surface) of the battery casing body, and to insulate the battery cell from the cover plate, thereby reducing the risk of short circuits. The insulating component can be made of plastic, rubber, or other insulating materials. Plastics can be polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), or polyvinyl chloride (PVC). Rubber can be fluororubber, nitrile rubber, or isobutyl rubber.

[0026] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0027] According to an embodiment of the present invention, in one aspect, a battery cell is provided, comprising: The housing assembly 10 includes a housing body 1 and a cover plate 2. The housing body 1 has an opening 11 at at least one end along a first direction, and the cover plate 2 is used to seal the opening 11. The housing body 1 includes a first housing portion 12 and a second housing portion 13 along the first direction. The first housing portion 12 is located closer to the opening 11 than the second housing portion 13. The thickness of the first housing portion 12 is greater than the thickness of the second housing portion 13. The thickness of the first housing portion 12 is E mm. Battery cell 4 is disposed inside housing assembly 10; An insulating component 5 is disposed between the cover plate 2 and the battery cell 4 along the first direction, and the minimum distance between the insulating component 5 and the inner wall of the shell body 1 is D mm. The cover plate 2 is welded to the shell body 1 in the area near the opening 11 to form a first weld line 3, and the maximum dimension of the first weld line 3 along the first direction is A mm; It satisfies: 0.032≤(A×E) / D≤12.

[0028] It should be noted that the first direction can specifically be the height direction of the battery cell. For ease of description, this application further defines the second direction as the width direction of the cover plate 2, which is also the thickness direction of the battery cell, that is, the arrangement direction of multiple battery cells along the thickness direction; the third direction is the length direction of the cover plate 2, which is also the length direction of the battery cell.

[0029] It should be noted that the first shell portion 12 and the second shell portion 13 can be two parts continuously disposed along the first direction of the shell body 1. The first shell portion 12 can be disposed on at least one side of the wall surface of the shell body 1 along the second direction, or symmetrically disposed on both sides along the second direction; in this case, the thickness direction of the first shell portion 12 is the second direction. Alternatively, the first shell portion 12 can also be disposed on at least one side of the wall surface of the shell body 1 along a third direction, or symmetrically disposed on both sides along the third direction; in this case, the thickness direction of the first shell portion 12 is the third direction. Regardless of which direction it is disposed in, the first shell portion 12 constitutes a locally thickened area of ​​the shell body 1.

[0030] In this embodiment, the housing assembly 10 includes a housing body 1 and a cover plate 2. The housing body 1 has an opening 11 at at least one end along the first direction. For example, the housing body 1 may have openings 11 at both ends along the first direction, and there may be two cover plates 2, which are used to block the openings 11 at both ends of the housing body 1 along the first direction. Alternatively, the housing body 1 may have an opening 11 at only one end along the first direction, and there may be one cover plate 2, which blocks the opening 11.

[0031] In this embodiment, the shell body 1 is constructed with uneven wall thickness. Specifically, the shell body 1 includes a first shell portion 12 and a second shell portion 13 along a first direction. The thickness of the first shell portion 12 is greater than the thickness of the second shell portion 13, and the first shell portion 12 is located closer to the opening 11 than the second shell portion 13, thereby enhancing the structural strength around the opening 11. Furthermore, during subsequent welding, the increased thickness of the first shell portion 12 can meet the greater welding power requirements, improve the welding stability between the shell body 1 and the cover plate 2, and enhance the connection strength between the shell body 1 and the cover plate 2.

[0032] The insulating component 5 is disposed between the cover plate 2 and the battery cell 4 along the first direction to block the electrical path between the cover plate 2 and the battery cell 4. However, the insulating component 5 is located relatively close to the opening 11, making it susceptible to deformation due to welding heat, which can cause the insulating component 5 to melt or carbonize, thereby reducing its insulation performance. In particular, when the first housing portion 12 is thickened, the temperature gradient in the area where the insulating component 5 is located intensifies as the welding heat input further increases, making it even easier for the insulating component 5 to deform due to heat.

[0033] The cover plate 2 and the shell body 1 are welded together in the area near the opening 11 to form the first weld line 3. The first weld line 3 refers to the weld structure formed by welding the cover plate 2 and the shell body 1. The first weld line 3 can be achieved by laser welding process. By focusing the laser beam on the interface between the shell body 1 and the cover plate 2, the local material melts and solidifies rapidly to form a dense weld structure, thereby achieving a reliable connection between the cover plate 2 and the shell body 1.

[0034] Understandably, in one implementation, the starting position of the thickened area of ​​the first housing portion 12 along the first direction can be flush with the edge of the opening and extend to the inside of the opening along the first direction; in another implementation, the starting position of the thickened area of ​​the first housing portion 12 along the first direction can be spaced apart from the edge of the opening, that is, there is another third housing portion (not shown in the figure) between the first housing portion 12 and the edge of the opening, the thickness of the third housing portion is less than the thickness of the first housing portion 12, in which case the first housing portion 12 can still meet the requirement of improving the strength of the housing structure; in the second implementation, the interval distance between the first housing portion 12 and the edge of the opening is in the range of 0.1mm-2mm, preferably 0.2mm-1mm. This embodiment improves the strength of the shell body 1 by setting the first housing portion 12, ensures the connection strength between the shell body 1 and the cover plate 2, increases the overall connection strength and size of the welding area, and avoids cracking of the weld line.

[0035] It should be noted that the minimum spacing between the insulating element 5 and the inner sidewall of the shell body 1 is D mm. Since the shell body 1 includes multiple sidewalls, the value of D mm specifically refers to the minimum vertical distance between the insulating element 5 and the sidewall of the shell body 1 that is closest to the shell body 1.

[0036] This embodiment ensures the welding strength of the shell body 1 and the cover plate 2 by comprehensively controlling the thickness E mm of the first shell part 12, the minimum gap distance D mm between the insulating part 5 and the inner sidewall of the shell body 1, and the maximum dimension A mm of the first welding line 3 along the first direction. This avoids cracking at the welding line of the shell assembly 10, effectively suppresses the conduction of welding heat to the insulating part 5, prevents the insulating part 5 from melting during the welding process, ensures the stable and reliable insulation performance of the insulating part 5, and reduces the safety risk of short circuit between the cover plate 2 and the battery cell 4.

[0037] Specifically, when the thickness E mm of the first housing portion 12 is too large, it will encroach on the internal space of the housing body 1 to a certain extent, resulting in limited installation space for the battery cell 4. It will also easily lead to a smaller distance between the insulating component 5 and the inner wall of the housing body 1, thus exacerbating the impact of welding heat on the insulating component 5. Furthermore, while a larger E mm increases the weld heat input, excessively high weld heat input can also increase the risk of heat damage to the insulating component 5. When the thickness E mm of the first housing portion 12 is too small, the structural strength of the housing body 1 around the opening 11 is insufficient. If the weld heat input is insufficient, incomplete welds are likely to occur during welding, leading to poor formation of the first weld wire 3 and cracking at the weld wire, thereby reducing connection reliability. If the weld heat input is excessive, it can easily cause localized melting and penetration of the housing body 1, easily damaging the insulating component 5 or the battery cell 4. Further research found that when the maximum dimension A mm of the first weld wire 3 along the first direction is too large, it reflects excessively high weld heat input, which can easily lead to increased weld penetration and an expanded heat-affected zone, exacerbating the risk of heat damage to the insulating component 5. When the dimension A mm of the first weld line 3 along the first direction is too small, the weld width is insufficient, the welding strength decreases, and the weld is prone to cracking due to vibration or thermal stress during subsequent use. This can lead to sealing failure between the cover plate 2 and the shell body 1, electrolyte leakage, etc., making it difficult to guarantee the connection strength. Further research found that when the minimum spacing D mm between the insulating component 5 and the inner wall of the shell body 1 is too small, the insulating component 5 and the shell body 1 become too close, shortening the welding heat conduction path. The insulating component 5 is more likely to absorb heat and soften or melt, thereby reducing the insulation performance of the insulating component 5. When the minimum spacing D mm between the insulating component 5 and the inner wall of the shell body 1 is too large, that is, the size of the insulating component 5 is reduced, although it can reduce the heat risk of the insulating component 5, it will encroach on the effective installation space of the electrode assembly and affect the overcurrent. Moreover, due to the smaller size of the insulating component 5, the assembly accuracy of the cell 4 decreases.

[0038] In the battery cell provided in this embodiment, since the insulating component 5 is located at the lower part of the cover plate 2, the risk of the insulating component 5 melting gradually increases as the welding depth of the first welding line 3 increases. By precisely controlling the synergistic relationship between E mm, A mm, and D mm, when the formula value of (A×E) / D is too large, it indicates that the proportion of A or E is too large, which means that the welding heat input is too strong, and the risk of heat damage to the insulating component 5 increases. Alternatively, if the proportion of D is too small, the distance between the insulating component 5 and the shell body 1 is too narrow. Even if the welding heat input does not increase significantly, the insulating component 5 is still prone to overheating due to the shortened heat conduction path, which increases the risk of heat damage to the insulating component 5 and may lead to a short circuit between the cover plate 2 and the cell 4, posing a significant safety risk. Conversely, when the value of (A×E) / D is too small, the proportion of A or E is too small, indicating insufficient welding heat input, limited weld penetration and width, reduced welding dimensions between cover plate 2 and shell body 1, low connection strength, increased risk of cracking at the weld line, which can easily lead to cover plate 2 coming off as a whole, or the proportion of D is too large, resulting in limited installation space for cell 4 and decreased battery energy density.

[0039] By limiting the upper limit of the formula (A×E) / D, the risk of heat damage to the insulating component 5 can be effectively suppressed, while ensuring that the weld has sufficient strength. By limiting the lower limit of the formula (A×E) / D, the reliability of the welding between the cover plate 2 and the shell body 1 can be guaranteed, and the assembly space utilization rate of the battery cell 4 in the shell assembly 10 can be guaranteed.

[0040] For example, when the formula (A×E) / D satisfies 0.032≤(A×E) / D≤12, in this embodiment, the specific value of (A×E) / D can be 0.032, 0.035, 0.046, 0.052, 0.066, 0.078, 0.091, 0.134, 0.141, 0.157, 0.196, 0.197, 0.235, 0.284, 0.321, 0.387, 0.452, 0.542, 0.613, 0.711, 0.771, or 0.82. 5 or 0.884 or 0.967 or 1.021 or 1.2 or 1.231 or 1.542 or 1.876 or 2.231 or 2.654 or 3.125 or 3.639 or 4.125 or 4.654 or 5.213 or 5.918 or 6.452 or 7.021 or 7.616 or 8.021 or 8.350 or 8.789 or 9.254 or 9.765 or 10.213 or 10.789 or 11.254 or 11.765 or 12, etc., or any two of the above values ​​forming an interval range.

[0041] As a preferred option, the value range of (A×E) / D is 0.14≤(A×E) / D≤1.2.

[0042] When the formula (A×E) / D takes the value within the preferred range of 0.14≤(A×E) / D≤1.2, the risk of heat damage to the insulation component 5 can be further reduced, while ensuring that the weld has good strength; it can guarantee the reliability of the welding between the cover plate 2 and the shell body 1, and effectively improve the utilization rate of the assembly space of the battery cell 4 in the shell assembly 10.

[0043] For example, when the formula (A×E) / D takes the value of 0.14≤(A×E) / D≤1.2, the value of (A×E) / D can specifically be 0.14 or 0.141 or 0.155 or 0.172 or 0.196 or 0.197 or 0.223 or 0.258 or 0.312 or 0.387 or 0.436 or 0.489 or 0.542 or 0.601 or 0.657 or 0.713 or 0.771 or 0.828 or 0.884 or 1.2, etc., or it can be any interval range formed by any two of the above values.

[0044] Regarding the measurement of dimensions, thickness, distance, and area involved in this application, a micrometer, caliper, or scanning electron microscope can be used to measure dimensions, thickness, distance, etc., and the area can be calculated from the dimensions.

[0045] Specifically, in this embodiment, the test method for A mm is as follows: on the surface of the battery where the first bonding wire is located, the weld width of the first bonding wire is measured using a micrometer (accuracy 0.01 mm). The measurement is performed 3 times, and the average value is recorded as A mm.

[0046] Specifically, in this embodiment, the test method for E mm is as follows: along the direction perpendicular to the first housing portion 12, the thickness of the first housing portion 12 is measured using a micrometer (accuracy 0.01 mm), the measurement is performed 3 times, and the average value is recorded as E mm.

[0047] Specifically, in this embodiment, the test method for D mm is as follows: use a micrometer (accuracy 0.01 mm) to measure the shortest distance between the inner wall of the shell body 1 and the insulating part 5, measure 3 times, take the average value, and record it as D mm.

[0048] The battery cells of this application can be prepared using the following methods: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., PVDF) are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheet is then obtained by rolling and slitting.

[0049] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98): (4~1): (4~1).

[0050] (2) Preparation of negative electrode: The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (SBR)) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, the negative electrode sheet is obtained by rolling and slitting.

[0051] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0052] (3) Preparation of electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0053] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0054] (5) Preparation of lithium-ion batteries: During casing fabrication, a protrusion is provided at the casing opening; the positive electrode, separator, and negative electrode are stacked in sequence and wound to form a battery cell; the insulating component is fixed to the cover plate; the electrode tabs of the battery cell are welded to the terminal assembly, placed in the battery casing, and the cover plate is welded to the casing. The battery is dried, electrolyte is injected, and after encapsulation, settling, formation, and volume adjustment, a lithium-ion battery is obtained.

[0055] In the selection of materials for the aforementioned battery, this application may also select other materials, not limited to those limited by the above preparation method. The positive electrode active material may be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. The conductive agent in the positive electrode sheet may also be selected from one or more of graphite, superconducting carbon, Ketjen black, Super P, carbon nanotubes, graphene, and carbon nanofibers. The binder in the positive electrode sheet may also be selected from one or more of polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene ternary copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene ternary copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan. The positive electrode current collector may also be selected from one or more of stainless steel with surface silver plating, stainless steel, aluminum, nickel, carbon electrode, carbon, nickel, and titanium. The positive electrode current collector may also include a composite current collector, which may include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming metallic materials (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.).

[0056] The negative electrode active material can be selected from one or more of the following negative electrode active main materials: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.; the conductive agent in the negative electrode sheet can be selected from one or more of the following: conductive carbon black, conductive graphite, carbon nanotubes, graphene, carbon fiber, etc.; the binder in the negative electrode sheet can be selected from one or more of the following: styrene-butadiene rubber, polyacrylic acid and its salts, sodium alginate, etc.; the thickener in the negative electrode sheet can be selected from one or more of the following: sodium carboxymethyl cellulose, polyacrylonitrile multi-component copolymer, etc.; the negative electrode current collector can also be selected from one or more of the following: stainless steel with silver plating, stainless steel, copper, nickel, carbon electrode, carbon, nickel, titanium, etc.; the negative electrode current collector can also include composite current collectors, which can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.). The negative electrode active layer includes the negative electrode active material, conductive components, adhesives, etc.

[0057] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0058] Referring to Table 1 below, the battery cell provided in this application was subjected to wire bonding cracking test and insulation melting test through several embodiments and comparative tests to verify its qualification.

[0059] Performance 1, Wire Cracking Test (used to measure whether cracking is likely to occur at the wire bonding point), the method is as follows: Following the battery preparation method described above, 200 batteries were prepared for each of the embodiments and comparative examples. The a, e, and d values ​​of the batteries in each embodiment are shown in Table 1 below. Apart from this, the remaining structures are the same. The batteries were charged at 1C to the upper limit voltage at 25°C, and then charged at a constant voltage until the cutoff current was 0.05C. A heating wire was placed on the periphery of the battery to continuously heat the battery and trigger thermal runaway. When thermal runaway occurred, heating was stopped. After the thermal runaway ended, it was observed whether cracking occurred at the first bonding wire position. If cracking occurred, the number of batteries with cracked first bonding wires was recorded as N. The bonding wire cracking rate = (N / 200) × 100%. If the bonding wire cracking rate is less than or equal to 2%, it is considered good. If the bonding wire cracking rate is greater than 2% and less than or equal to 5%, it is considered qualified. If the bonding wire cracking rate is greater than 5%, it is considered unqualified.

[0060] Different battery systems require corresponding adjustments to their upper and lower voltage limits: For cathode active materials including LFP (LiFePO4, lithium iron phosphate) – upper limit voltage 3.65V, lower limit voltage 2.5V; for cathode active materials including NCM (lithium nickel cobalt manganese oxide) – upper limit voltage 4.25V, lower limit voltage 2.5V; for cathode active materials including LFMP (lithium manganese iron phosphate) – upper limit voltage 4.25V, lower limit voltage 2.5V; for cathode active materials including lithium nickel manganese oxide – upper limit voltage 4.8V, lower limit voltage 3.5V.

[0061] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode active materials all meet the above test requirements, and the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and other negative electrode active materials all meet the above test requirements, and the mass ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0062] Performance 2, Insulating component melting test, the method is as follows: Following the battery preparation method described above, 200 batteries were prepared for each of the embodiments and comparative examples. The a, e, and d values ​​of the batteries in each embodiment are shown in Table 1 below. Apart from this, the other structures are the same.

[0063] Disassemble the battery and observe whether the edge of the insulating part near the first housing has melted. If it has melted, record the number of batteries melted by the insulating part as N. The melting rate of the insulating part = (N / 200) × 100%. If the melting rate of the insulating part is less than or equal to 1%, it is good. If the melting rate of the insulating part is greater than 1% and less than or equal to 3%, it is qualified. If the melting rate of the insulating part is greater than 3%, it is unqualified.

[0064] Table 1

[0065] Regarding the test results, referring to Table 1 above, the explanation is as follows: As can be seen from Examples 1-18, when the value of the formula (A×E) / D meets the above range, the test results of the wire bonding cracking test are all qualified or good, and no unqualified results are found; the test results of the insulation melting test are all qualified or good; and the performance requirements are met.

[0066] In Comparative Examples 1 and 3, the value of (A×E) / D was below the lower limit, resulting in a failure to meet the performance requirements after the wire bonding cracking test. In Comparative Examples 2 and 4, the value of (A×E) / D exceeded the upper limit, resulting in a failure to meet the performance requirements after the insulation melting test.

[0067] In some embodiments, combined with Figure 6 As shown, the insulating member 5 includes an insulating member body 51. A flange structure 52 is formed protruding from the edge of the insulating member 5 near the shell body 1. The flange structure 52 extends from the insulating member body 51 along a first direction toward the side near the battery cell 4.

[0068] The insulating component body 51 has a plate-like structure. By protruding a flange structure 52 at the edge of the insulating component 5 near the shell body 1, the thickness at the edge of the insulating component 5 can be increased, thereby improving the thermal stability and anti-melting ability of the insulating component 5 during the process of being affected by welding heat, avoiding the melting of the insulating component 5, and thus reducing the risk of short circuit between the cover plate 2 and the cell 4, and ensuring battery safety.

[0069] Specifically, flange structures 52 can be provided on all four edges of the insulating body 51, or flange structures 52 can be provided on at least one edge of the insulating body 51.

[0070] In some embodiments, the flange structure 52 extends from the insulating body 51 along the first direction by a dimension of B mm, satisfying 2 mm ≤ B mm ≤ 10 mm.

[0071] The flange structure 52 extends from the insulating body 51 along the first direction toward the side closer to the cell 4. By limiting the lower limit of the dimension B mm of the flange structure 52 extending from the insulating body 51 along the first direction, it can be ensured that the flange structure 52 has sufficient physical height to effectively resist welding heat conduction, prevent the insulating part 5 from melting due to local overheating, ensure the structural stability of the insulating part 5, and improve the insulation reliability. By limiting the upper limit of the dimension B mm of the flange structure 52 extending from the insulating body 51 along the first direction, it can be avoided that the flange structure 52 extends excessively along the first direction and occupies the installation space of the cell 4, thus affecting the overall energy density of the battery.

[0072] For example, in this embodiment, the value of B mm can be 2 mm, 2.7 mm, 3.4 mm, 4.1 mm, 4.9 mm, 5.6 mm, 6.3 mm, 7.1 mm, 7.8 mm, 8.5 mm, 9.2 mm, or 10 mm, or it can be any range formed by any two of the above values.

[0073] In some embodiments, the thickness of the flange structure 52 is C mm, satisfying 0.05 mm ≤ C mm ≤ 1 mm.

[0074] In this embodiment, the thickness of the flange structure 52 specifically refers to the cross-sectional dimension of the flange structure 52 perpendicular to the first direction. For example, when the flange structure 52 is disposed on the edge of the insulating body 51 along the second direction, C mm is the thickness of the flange structure 52 along the second direction; when the flange structure 52 is disposed on the edge of the insulating body 51 along the third direction, C mm is the thickness of the flange structure 52 along the third direction.

[0075] By limiting the lower limit of the thickness C mm of the flange structure 52, it can be ensured that the flange structure 52 has sufficient physical thickness to effectively resist welding heat conduction, prevent the insulation component 5 from melting due to local overheating, ensure the structural stability of the insulation component 5, and improve the insulation reliability. On the other hand, by limiting the upper limit of the thickness C mm of the flange structure 52, it can be avoided that the flange structure 52 is too thick, which would increase the overall weight and limit the installation space of the cell 4, thereby affecting the overall energy density of the battery.

[0076] As a further preferred option, the thickness of the flange structure 52 is C mm, satisfying 0.1 mm ≤ C mm ≤ 0.3 mm.

[0077] For example, in this embodiment, the value of C mm can be 0.05 mm, 0.08 mm, 0.13 mm, 0.19 mm, 0.26 mm, 0.34 mm, 0.43 mm, 0.52 mm, 0.63 mm, 0.74 mm, 0.85 mm, 0.93 mm, or 1 mm, or it can be any range formed by any two of the above values.

[0078] In some embodiments, the edge of the insulating member 5 extends beyond the cell 4 along the thickness direction perpendicular to the first housing portion 12.

[0079] It should be noted that the edge of the insulating component 5 refers to the outer periphery of the insulating component 5 when it is considered as a whole.

[0080] By setting the edge of the insulating member 5 beyond the end face of the cell 4 along the thickness direction perpendicular to the first housing portion 12, direct contact between the end face of the cell 4 and the housing body 1 can be avoided, thereby reducing the damage to the end of the cell 4 caused by welding heat radiation. At the same time, air or electrolyte can be used to form a thermal buffer zone between the cell 4 and the housing body 1, further delaying the conduction of heat into the cell 4.

[0081] In some embodiments, along the thickness direction perpendicular to the first housing portion 12, the edge of the insulating member 5 extends beyond the cell 4 by a dimension F mm, satisfying 0.5 mm ≤ F mm ≤ 10 mm.

[0082] By limiting the lower limit of F mm, effective thermal isolation can be ensured between the end face of the cell 4 and the casing body 1, preventing the high temperature of welding from being directly conducted to the cell 4 and avoiding damage to the cell 4; while limiting the upper limit of F mm can prevent the gap between the cell 4 and the casing body 1 from being too large, which would reduce the utilization rate of the internal space of the battery and thus affect the overall energy density and structural compactness of the battery.

[0083] For example, in this embodiment, the value of F mm can be 0.5 mm, 0.8 mm, 1.3 mm, 2 mm, 2.7 mm, 3.5 mm, 4.2 mm, 5 mm, 5.9 mm, 6.8 mm, 7.7 mm, 8.5 mm, 9.3 mm, or 10 mm, or it can be any range formed by any two of the above values.

[0084] In some embodiments, the cover plate 2 includes a first cover plate surface 21 facing the side of the battery cell 4 in a first direction; Along the first direction, the projection of the insulating element 5 toward the surface 21 of the first cover plate is located within the area of ​​the surface 21 of the first cover plate.

[0085] That is, along the second direction or along the third direction, the edge of the insulating element 5 does not extend beyond the edge of the first cover plate surface 21.

[0086] By limiting the projection of the insulating element 5 in the first direction to be completely within the range of the first cover plate surface 21, it can be ensured that the edge of the insulating element 5 will not be exposed outside the cover plate 2, thereby avoiding damage to the edge of the insulating element 5 from external forces such as mechanical scratching and squeezing during assembly or use. At the same time, it ensures that after assembly, a reasonable gap is maintained between the edge of the insulating element 5 and the inner wall of the shell body 1, avoiding the direct conduction of welding heat during the welding process to the insulating element 5, and preventing the insulating element 5 from melting due to overheating.

[0087] In some embodiments, combined with Figure 6 As shown, along the thickness direction perpendicular to the first housing portion 12, the distance between the edge of the insulating member 5 and the corresponding edge of the first cover plate surface 21 is G mm, which satisfies 0.2 mm ≤ G mm ≤ 4 mm.

[0088] By limiting the lower limit of G mm, sufficient gap can be maintained between the edge of the insulating component 5 and the cover plate 2 to prevent interference or extrusion deformation during assembly. At the same time, it ensures that the edge of the insulating component 5 does not come into contact with the inner wall of the shell body 1, preventing welding heat from being conducted to the insulating component 5 through the side wall of the shell body 1 and preventing the insulating component 5 from melting due to overheating. Meanwhile, by limiting the upper limit of G mm, the gap between the edge of the insulating component 5 and the cover plate 2 can be prevented from being too large, which would result in insufficient coverage of the end face of the battery cell 4 by the insulating component 5, thereby reducing the support performance of the battery cell 4 and posing a risk of insulation failure.

[0089] As a further preferred option, the value range of G mm satisfies 1 mm ≤ G mm ≤ 2.5 mm.

[0090] For example, in this embodiment, the value of G mm can be 0.2 mm, 0.45 mm, 0.7 mm, 1.1 mm, 1.55 mm, 2 mm, 2.45 mm, 2.9 mm, 3.35 mm, 3.7 mm, or 4 mm, or it can be any range formed by any two of the above values.

[0091] In some embodiments, the cover plate 2 includes a main body portion 22 and a boss portion 23 extending from the main body portion 22 toward the side of the battery cell 4 in a first direction. The boss portion 23 is adapted to be inserted into the interior of the housing body 1, and in the direction perpendicular to the first direction, the boss portion 23 is at least partially opposite to the first housing portion 12.

[0092] Combination Figure 6 As shown, the cover plate 2 includes two parts, an upper part being the main body 22 and a lower part being the boss 23. In the assembled state, the main body 22 can fit against the top end face of the shell body 1 or extend into the shell body 1; while the boss 23 is embedded inside the shell body 1.

[0093] Optionally, the boss portion 23 can be tightly fitted with the inner wall of the shell body 1 to enhance structural stability and suppress welding deformation. Additionally, the outer peripheral surface of the boss portion 23 can form an interference fit or a clearance fit with the inner wall of the first shell portion 12.

[0094] Furthermore, in the direction perpendicular to the first direction, the boss portion 23 is at least partially opposite to the first housing portion 12, thereby increasing the contact area between the cover plate 2 and the housing body 1, and enabling more areas of the cover plate 2 and the housing body 1 to be welded together, improving the overall welding strength and ensuring sealing reliability.

[0095] In some embodiments, the first bonding line 3 is at least partially formed in the region where the boss portion 23 contacts the first housing portion 12.

[0096] That is, at least a portion of the area where the boss portion 23 contacts the first housing portion 12 melts when subjected to welding heat and forms a first weld line 3 after cooling and solidification, so as to enhance the connection strength between the boss portion 23 and the first housing portion 12.

[0097] In some embodiments, the cover plate 2 includes a first cover plate surface 21 facing the side of the battery cell 4 in a first direction; Along the first direction, and from the cover plate 2 toward the cell 4, the end of the first housing portion 12 away from the opening 11 extends beyond the surface 21 of the first cover plate.

[0098] By positioning the end of the first housing portion 12 away from the opening 11 beyond the surface 21 of the first cover plate, the welding position can be prevented from being too close to the end of the first housing portion 12 away from the opening 11, thereby effectively avoiding stress concentration areas and better ensuring the connection strength between the housing body 1 and the cover plate 2. At the same time, it avoids the cover plate 2 occupying a large amount of space in the height direction inside the housing body 1, ensuring energy density.

[0099] In some embodiments, along the first direction, the distance between the end of the first housing portion 12 away from the opening portion 11 and the surface of the first cover plate 21 is H mm, satisfying 2 mm ≤ H mm ≤ 15 mm.

[0100] Combination Figure 5 As shown, by limiting the lower limit of H mm, the weld can be kept away from the stress concentration area, ensuring the connection strength between the shell body 1 and the cover plate 2; at the same time, by limiting the upper limit of H mm, the first shell part 12 can be prevented from extending excessively and encroaching on the installation space of the cell 4, thus balancing structural strength and battery energy density.

[0101] As a further preferred option, the value range of H mm satisfies 4 mm ≤ H mm ≤ 9 mm.

[0102] For example, in this embodiment, the value of H mm can be 2 mm, 3.2 mm, 4.5 mm, 5.8 mm, 7.1 mm, 8.4 mm, 9.7 mm, 11 mm, 12.3 mm, 13.6 mm, 14.9 mm, or 15 mm, or it can be any range formed by any two of the above values.

[0103] In some embodiments, the boss portion 23 includes a boss sidewall 231 disposed opposite to the first housing portion 12, and the boss portion 23 also includes a first cover plate surface 21 facing the side of the battery cell 4 in a first direction. A chamfer 232 is formed between the boss sidewall 231 and the surface 21 of the first cover plate. The chamfer 232 is adapted to allow at least a portion of the boss portion 23 to be spaced apart from the first housing portion 12.

[0104] Combination Figure 7 As shown, the insulating component 5 is fitted to the surface 21 of the first cover plate. By providing a chamfered portion 232 between the side wall 231 of the boss and the surface 21 of the first cover plate, a gap can be formed between at least a portion of the boss portion 23 and the side wall of the shell body 1. Specifically, the chamfered portion 232 can form a gap between the surface 21 of the first cover plate of the boss portion 23 and the first shell portion 12, thereby better isolating the welding heat and avoiding damage to the insulating component 5 caused by high temperature.

[0105] In this embodiment, the chamfered portion 232 can be a rounded corner structure, a beveled surface structure, or other multi-level transition structure.

[0106] In some embodiments, the maximum dimension of the chamfered portion 232 along the direction perpendicular to the thickness of the first housing portion 12 is J mm, satisfying 0.2 mm ≤ J mm ≤ 1.2 mm.

[0107] By limiting the lower limit of J mm, the chamfered portion 232 can be ensured to have sufficient structural transition space, ensuring that a gap is formed between the first cover plate surface 21 of the boss portion 23 and the first housing portion 12, so that the chamfered portion 232 can effectively block heat conduction; by limiting the upper limit of J mm, the chamfer can be prevented from excessively weakening the structural rigidity of the boss portion 23, ensuring that the boss portion 23 provides stable support for the insulating component 5 after assembly.

[0108] For example, in this embodiment, the value of J mm can be 0.2 mm, 0.28 mm, 0.37 mm, 0.45 mm, 0.53 mm, 0.62 mm, 0.71 mm, 0.8 mm, 0.89 mm, 0.98 mm, 1.07 mm, 1.16 mm, or 1.2 mm, or it can be any range formed by any two of the above values.

[0109] In some embodiments, the maximum dimension of the chamfered portion 232 along the first direction is K mm, satisfying 0.2 mm ≤ K mm ≤ 1.2 mm.

[0110] By limiting the lower limit of K mm, the chamfered portion 232 can be ensured to have an effective thermal buffer depth on the side near the battery cell, thus ensuring the extension of the heat conduction path and further reducing the impact of high temperature on the insulating component 5. By limiting the upper limit of K mm, the size of the chamfered portion 232 along the first direction can be avoided from being too large, which would reduce the contact area between the boss sidewall 231 and the first housing portion 12, affecting the structural stability and sealing reliability, and also affecting the welding quality between the cover plate 2 and the housing body 1.

[0111] For example, in this embodiment, the value of K mm can be 0.2 mm, 0.28 mm, 0.37 mm, 0.45 mm, 0.53 mm, 0.62 mm, 0.71 mm, 0.8 mm, 0.89 mm, 0.98 mm, 1.07 mm, 1.16 mm, or 1.2 mm, or it can be any range formed by any two of the above values.

[0112] In some embodiments, along the thickness direction perpendicular to the first housing portion 12, the minimum interval between the edge of the insulating member 5 and the chamfered portion 232 is L mm, satisfying 0.1 mm ≤ L mm ≤ 3.3 mm.

[0113] By limiting the lower limit of L mm, a sufficient safe distance can be maintained between the edge of the insulating component 5 and the chamfered portion 232. This prevents assembly deviations or thermal expansion from causing the insulating component 5 to overlap with the chamfered portion 232 at least partially, thus resulting in insufficient support for the insulating component 5. Simultaneously, it avoids the high temperatures generated during welding directly acting on the edge of the insulating component 5, preventing it from melting during welding and ensuring stable and reliable insulation performance. Furthermore, by limiting the upper limit of L mm, excessive spacing can prevent the overall size of the insulating component 5 from becoming too small, affecting the integrity and protective effect of the insulating component 5 on the battery cell 4, thereby weakening the overall safety of the battery.

[0114] For example, in this embodiment, the value of L mm can be 0.1 mm, 0.25 mm, 0.48 mm, 0.72 mm, 0.95 mm, 1.2 mm, 1.53 mm, 1.87 mm, 2.2 mm, 2.55 mm, 2.88 mm, 3.12 mm, or 3.3 mm, or it can be any range formed by any two of the above values.

[0115] In some embodiments, the following is satisfied: 0.5mm≤A mm≤2.5mm; and / or, 0.2mm≤E mm≤1.5mm; and / or, 0.3mm≤D mm≤3.5mm.

[0116] Specifically, when the thickness E mm of the first housing portion 12 is too large, it will encroach on the internal space of the housing body 1 to a certain extent, resulting in limited installation space for the battery cell 4. It will also easily lead to a smaller distance between the insulating component 5 and the inner wall of the housing body 1, thus exacerbating the impact of welding heat on the insulating component 5. Furthermore, while a larger E mm increases the heat input it can withstand, excessively high heat input can also increase the risk of the insulating component 5 being overheated. When the thickness E mm of the first housing portion 12 is too small, the structural strength of the housing body 1 around the opening 11 is insufficient. If the welding heat input is insufficient, incomplete welds are likely to occur during welding, leading to poor formation of the first weld line 3 and cracking at the weld line, thereby reducing connection reliability. If the welding heat input is excessive, it can easily cause localized melting and penetration of the housing body 1, easily damaging the insulating component 5 or the battery cell 4. In other words, controlling E mm within the range of 0.2 mm ≤ E mm ≤ 1.5 mm can ensure the structural strength and welding reliability of the housing body 1 while isolating the welding heat conduction path, reducing the risk of the insulating component 5 being damaged by high temperatures.

[0117] For example, when the value of E mm satisfies the range of 0.2mm ≤ E mm ≤ 1.5mm, the value of E mm can be 0.2mm or 0.21mm or 0.22mm or 0.25mm or 0.28mm or 0.31mm or 0.34mm or 0.37mm or 0.4mm or 0.41mm or 0.43mm or 0.46mm or 0.49mm or 0.52mm or 0.54mm or 0.57mm or 0.61mm or 0.62mm or 0.65mm or 0.68mm or 0.71mm or 0.74mm or 0.77mm or 0.79mm or 0.8mm or 0.85mm or 0.9mm or 0.95mm or 1.13mm or 1.24mm or 1.31mm or 1.35mm or 1.4mm or 1.45mm or 1.5mm, etc., or it can be any range formed by any two of the above values.

[0118] Specifically, when the dimension A mm of the first weld line 3 along the first direction is too large, it reflects excessive welding heat input, which easily leads to increased weld penetration and expansion of the heat-affected zone, exacerbating the risk of heat damage to the insulating component 5. Conversely, when the dimension A mm of the first weld line 3 along the first direction is too small, the weld penetration is insufficient, the welding strength decreases, and the weld is prone to cracking due to vibration or thermal stress during subsequent use, leading to sealing failure between the cover plate 2 and the shell body 1, electrolyte leakage, etc., making it difficult to guarantee the connection strength. That is, controlling A mm within the range of 0.5 mm ≤ A mm ≤ 2.5 mm can ensure that the weld has a certain mechanical strength to resist external vibration and internal pressure, and can also limit the expansion of the heat-affected zone to a certain extent, avoiding excessive conduction of high temperature to the insulating component 5.

[0119] For example, when the value of A mm satisfies 0.5mm ≤ A mm ≤ 2.5mm, in this embodiment, the value of A mm can specifically be 0.5mm or 0.55mm or 0.62mm or 0.71mm or 0.75mm or 0.8mm or 0.81mm or 0.88mm or 0.94mm or 1mm or 1.12mm or 1.23mm or 1.3mm or 1.37mm or 1.45mm or 1.5mm or 1.59mm or 1.6mm or 1.68mm or 1.75mm or 1.82mm or 1.94mm or 2mm or 2.1mm or 2.19mm or 2.3mm or 2.4mm or 2.47mm or 2.49mm or 2.5mm, etc., or it can be any range formed by any two of the above values.

[0120] Specifically, when the minimum distance D mm between the insulating component 5 and the inner wall of the casing 1 is too small, the insulating component 5 becomes too close to the casing 1, shortening the welding heat conduction path. This makes the insulating component 5 more susceptible to absorbing heat and softening or melting, thus reducing its insulation performance. Conversely, when the minimum distance D mm between the insulating component 5 and the inner wall of the casing 1 is too large, while it reduces the risk of the insulating component 5 being heated, it encroaches on the effective installation space of the battery cell 4, increasing the redundancy of the internal space of the casing assembly 10. This leads to a decrease in the assembly accuracy of the battery cell 4 and is detrimental to the overall lightweight design of the battery. In other words, controlling D mm within the range of 0.3 mm ≤ D mm ≤ 3.5 mm can reduce the conduction of welding heat to the insulating component 5, ensuring stable insulation performance of the insulating component 5, while also maintaining the assembly accuracy of the battery cell 4 and ensuring the energy density of the battery pack.

[0121] For example, when the value of D mm is within the range of 0.3mm ≤ D mm ≤ 3.5mm, the value of D mm can be 0.3mm or 0.32mm or 0.35mm or 0.38mm or 0.41mm or 0.43mm or 0.46mm or 0.5mm or 0.55mm or 0.6mm or 0.68mm or 0.73mm or 0.8mm or 0.85mm or 0.9mm or 1mm or 1.02mm or 1.1mm or 1.15mm or 1.23mm or 1.31mm or 1.4mm or 1.5mm or 1.6mm or 1.7mm or 1.83mm or 2mm or 2.2mm or 2.48mm or 2.5mm or 2.61mm or 2.8mm or 3mm or 3.12mm or 3.2mm or 3.3mm or 3.41mm or 3.5mm, etc., or it can be any range formed by any two of the above values.

[0122] Preferably, the dimension A mm of the first bonding line 3 along the first direction can be in the range of 0.8 mm ≤ A mm ≤ 1.6 mm.

[0123] When the value of A mm meets the preferred range of 0.8 mm ≤ A mm ≤ 1.6 mm, it can ensure that the weld has sufficient mechanical strength to resist external vibration and internal pressure, and effectively limit the expansion of the heat-affected zone, avoiding excessive conduction of high temperature to the insulating component 5.

[0124] For example, when the value of A mm satisfies the preferred range of 0.8 mm ≤ A mm ≤ 1.6 mm, the value of A mm can be 0.8 mm, 0.81 mm, 0.85 mm, 0.89 mm, 0.92 mm, 0.94 mm, 0.98 mm, 1.02 mm, 1.06 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.23 mm, 1.27 mm, 1.31 mm, 1.34 mm, 1.37 mm, 1.4 mm, 1.43 mm, 1.46 mm, 1.49 mm, 1.5 mm, 1.53 mm, 1.56 mm, 1.59 mm, or 1.6 mm, or it can be any range formed by any two of the above values.

[0125] Preferably, the thickness E mm of the first housing portion 12 can be in the range of 0.4 mm ≤ E mm ≤ 0.8 mm.

[0126] When the value of E mm meets the preferred range of 0.4 mm ≤ E mm ≤ 0.8 mm, the structural strength and welding reliability of the shell body 1 can be better guaranteed, while effectively isolating the welding heat conduction path and further reducing the risk of the insulating component 5 being damaged by high temperature.

[0127] For example, when the value of E mm satisfies the preferred range of 0.4 mm ≤ E mm ≤ 0.8 mm, the value of E mm can be 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, 0.51 mm, 0.52 mm, 0.54 mm, 0.55 mm, 0.56 mm, 0.57 mm, 0.58 mm, 0.59 mm, 0.61 mm, 0.62 mm, 0.63 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.68 mm, 0.69 mm, 0.7 mm, 0.71 mm, 0.75 mm, 0.79 mm, or 0.8 mm, etc., or it can be any range formed by any two of the above values.

[0128] Preferably, in the direction perpendicular to the first direction, the minimum distance Dmm between the insulating member 5 and the inner wall of the shell body 1 can be in the range of 1mm≤Dmm≤2.5mm.

[0129] When the value of D mm is within the preferred range of 1 mm ≤ D mm ≤ 2.5 mm, the conduction of welding heat to the insulating component 5 can be further reduced, ensuring the stability of the insulation performance of the insulating component 5, while taking into account the assembly accuracy of the battery cell 4, and better ensuring the energy density of the battery pack.

[0130] For example, when the value of D mm satisfies the preferred range of 1 mm ≤ D mm ≤ 2.5 mm, the value of D mm can be 1 mm or 1.05 mm or 1.1 mm or 1.15 mm or 1.23 mm or 1.28 mm or 1.31 mm or 1.36 mm or 1.4 mm or 1.45 mm or 1.5 mm or 1.55 mm or 1.6 mm or 1.65 mm or 1.7 mm or 1.75 mm or 1.83 mm or 1.88 mm or 1.93 mm or 1.98 mm or 2.03 mm or 2.08 mm or 2.13 mm or 2.18 mm or 2.23 mm or 2.28 mm or 2.33 mm or 2.38 mm or 2.43 mm or 2.48 mm or 2.5 mm, or it can be any range formed by any two of the above values.

[0131] In some embodiments, along the first direction and from the cover plate 2 toward the cell 4, the end face of the insulating member 5 near the cell 4 does not extend beyond the end of the first housing portion 12 away from the opening portion 11. In this case, the following condition is satisfied: 0.032≤(A×E) / D≤11.5.

[0132] Along the first direction, and from the cover plate 2 toward the cell 4, the end face of the insulating member 5 near the cell 4 does not extend beyond the end of the first housing portion 12 away from the opening 11. That is, the extension length of the first housing portion 12 along the first direction is longer, and the insulating member 5 is completely covered within the extension range of the first housing portion 12. Compared to when the extension length of the first housing portion 12 along the first direction is shorter, since the thickness of the first housing portion 12 is greater than the thickness of the second housing portion 13, the minimum distance D mm between the insulating member 5 and the inner wall of the housing body 1 will be smaller, thereby increasing the risk of thermal damage to the insulating member 5; therefore, it is necessary to reasonably control the upper limit of (A×E) / D to ensure that the welding heat input is within the safe threshold and to avoid damage to the insulating member 5.

[0133] In some embodiments, the battery cell 4 includes a battery cell body 41 and a tab 42 extending from at least one end of the battery cell body 41; the tab 42 is disposed between the battery cell body 41 and the insulating member 5; The battery cell also includes a terminal assembly 6, which is disposed on the cover plate 2 and is electrically connected to the tab 42. Along the direction perpendicular to the thickness of the first housing portion 12, the minimum interval between the edge of the insulating member 5 and the tab portion 42 is M mm, satisfying 0.1 mm ≤ M mm ≤ 3.6 mm.

[0134] Combination Figure 5 As shown, in this embodiment, the battery cell body 41 is provided with a tab 42 on the side facing the cover plate 2. The tab 42 is bent into a U-shape and then welded to the electrode assembly 6.

[0135] In this embodiment, the minimum interval M mm between the edge of the insulating member 5 and the tab 42 is defined. Specifically, it can refer to the shortest straight-line distance between the bent area of ​​the tab 42 and the edge of the insulating member 5 in the direction perpendicular to the thickness of the first housing portion 12.

[0136] By limiting the lower limit of M mm, it can be ensured that the heat generated by the tab 42 during charging and discharging will not be directly conducted to the insulating component 5 due to the close distance, causing the insulating component 5 to overheat and fail. At the same time, by limiting the upper limit of M mm, it can be avoided that the distance between the tab 42 and the insulating component 5 is too large, which would increase the overall thickness of the battery cell and affect the energy density. It can also be avoided that the insulating component 5 is too close to the shell body 1, which would make the insulating component 5 more susceptible to the heat of welding and melt.

[0137] For example, in this embodiment, the value of M mm can be 0.1 mm, 0.35 mm, 0.62 mm, 0.9 mm, 1.25 mm, 1.6 mm, 1.98 mm, 2.35 mm, 2.72 mm, 3.1 mm, 3.45 mm, or 3.6 mm, or it can be any range formed by any two of the above values.

[0138] In some embodiments, the shell body 1 includes an adjacent first shell wall 101 and a second shell wall 102, which are arranged perpendicularly. The first shell wall 101 has a first inner side facing the battery cell 4, and the minimum spacing between the insulating member 5 and the first inner side is D1 mm (not shown in the figure) in a direction perpendicular to the first direction. The second shell wall 102 has a second inner side facing the battery cell 4, and the minimum spacing between the insulating member 5 and the second inner side is D2 mm (not shown in the figure), wherein D1 mm is not equal to D2 mm.

[0139] The battery cell in this embodiment is a prismatic battery. The shell body 1 has a cuboid structure and includes an adjacent first shell wall 101 and a second shell wall 102. The first shell wall 101 can correspond to the long side wall of the battery cell, and the second shell wall 102 can correspond to the short side wall of the battery cell.

[0140] By ensuring that D1 mm ≠ D2 mm, the differences in welding heat conduction paths in different directions can be accommodated, thus preventing the overall outer edge of the insulating component 5 from melting.

[0141] In some embodiments, the area of ​​the first shell wall 101 is greater than the area of ​​the second shell wall 102, satisfying: D1 mm > D2 mm.

[0142] The area of ​​the first shell wall 101 is larger than that of the second shell wall 102. That is, the first shell wall 101 corresponds to a longer weld area, and the heat accumulation is more significant. Therefore, a larger D1 mm is required to enhance the heat dissipation margin. The weld of the second shell wall 102 is shorter and the heat input is relatively smaller. The D2 mm can be appropriately reduced to optimize the utilization of internal space.

[0143] In some embodiments, at least a portion of the first housing portion 12 forms a first bonding line 3.

[0144] In one implementation, the starting position of the first shell portion 12 along the first direction can be flush with the edge of the opening portion 11 and extend to the inside of the opening portion 11 along the first direction; in another implementation, the starting position of the first shell portion 12 along the first direction can be spaced apart from the edge of the opening portion 11, that is, there is also a third shell portion (not shown in the figure) between the first shell portion 12 and the edge of the opening portion 11. In this case, the wall thickness of the first shell portion 12 can still meet the requirement of improving the structural strength of the shell body 1.

[0145] This embodiment further defines at least a portion of the first housing portion 12 to form the first welding line 3, that is, the first welding line 3 is directly located on the thickened area of ​​the housing body 1, which better ensures the connection strength between the housing body 1 and the cover plate 2.

[0146] In some embodiments, along the first direction, the end of the first housing portion 12 away from the opening portion 11 is spaced apart from the first welding line 3, and the spacing distance is N mm, satisfying 0.5 mm ≤ N mm ≤ 18 mm.

[0147] Combination Figure 5 As shown, because the end of the first shell portion 12 away from the opening 11, which is also the transition area connecting the first shell portion 12 and the second shell portion 13, the material thickness of the shell body 1 is reduced at this point, making it prone to stress concentration and resulting in relatively weak structural strength. Since the welded area between the shell body 1 and the cover plate 2 will recrystallize after welding, if the first weld line 3 is too close to the junction of the first shell portion 12 and the second shell portion 13, a heat-affected zone will form at the edge of the first weld line 3. The hardness of the heat-affected zone is weaker than that of the shell body 1, leading to a greater risk of fracture at the junction and thus exacerbating the risk of structural failure.

[0148] By limiting the lower limit of N mm, it can be ensured that the weld is far away from the stress concentration area, thus guaranteeing the connection strength between the shell body 1 and the cover plate 2. At the same time, by limiting the upper limit of N mm, it can be avoided that the first shell part 12 extends excessively and encroaches on the installation space of the cell 4, thus balancing structural strength and battery energy density.

[0149] For example, in this embodiment, the value of N mm can be 0.5 mm, 1.2 mm, 2.7 mm, 4.3 mm, 6.1 mm, 8.5 mm, 10.2 mm, 12.8 mm, 14.6 mm, 16.3 mm, 17.9 mm, or 18 mm, or it can be any range formed by any two of the above values.

[0150] In some embodiments, the first housing portion 12 includes a region of equal thickness 121 and a region of non-equal thickness 122, and the region of non-equal thickness 122 is disposed between the region of equal thickness 121 and the second housing portion 13 along a first direction.

[0151] By forming a non-uniform thickness region 122 between the uniform thickness region 121 and the second shell portion 13, the wall thickness transitions smoothly from the uniform thickness region 121 to the second shell portion 13, effectively alleviating stress abrupt changes at the junction, avoiding stress concentration between the first shell portion 12 and the second shell portion 13, and reducing the risk of cracking of the shell body 1. At the same time, by setting the non-uniform thickness region 122, the weakening effect of the welding heat-affected zone on the structural strength can be reduced.

[0152] In this implementation, the height of the equal thickness zone 121 is 0.8mm-14mm, and the height of the non-equal thickness zone 122 is 0.6mm-8mm.

[0153] In some embodiments, the thickness of the non-uniform thickness region 122 gradually decreases in the direction toward the second housing portion 13.

[0154] Furthermore, the thickness reduction rate of the non-uniform thickness region 122 changes linearly, ensuring a uniform wall thickness transition and avoiding sudden increases in local stress. This facilitates processing and forming.

[0155] In some embodiments, along a direction perpendicular to the first direction, the first housing portion 12 is at least partially opposite to the battery cell 4, satisfying: 0.5mm ≤ D mm ≤ 3.5mm.

[0156] That is, along the second direction and / or the third direction, there is an overlapping area between the projection of the first housing part 12 on the cell 4 and the outer contour of the cell 4. At this time, the area where the first housing part 12 overlaps with the projection of the cell 4 will result in a small minimum spacing distance D mm between the insulating member 5 and the inner sidewall of the housing body 1, which is prone to insulation failure risk. Therefore, it is necessary to appropriately increase D mm to ensure insulation safety margin.

[0157] For example, in this embodiment, the value of D mm can be 0.5 mm, 0.72 mm, 0.95 mm, 1.2 mm, 1.55 mm, 1.88 mm, 2.2 mm, 2.55 mm, 2.88 mm, 3.12 mm, 3.35 mm, or 3.5 mm, or it can be any range formed by any two of the above values.

[0158] In some other embodiments, the projection of the first housing portion 12 and the cell 4 does not overlap along a direction perpendicular to the first direction.

[0159] That is, along the direction perpendicular to the first direction, the projection of the battery cell 4 and the second housing part 13 overlaps. At this time, the minimum distance between the battery cell 4 and the inner sidewall of the housing body 1 is appropriately increased, which can reduce the risk of the battery cell 4 being affected by welding heat.

[0160] In some embodiments, the ratio of the size of the first housing portion 12 to the size of the second housing portion 13 along the first direction is 0.006-0.44.

[0161] In this embodiment, the dimension of the second housing portion 13 along the first direction ranges from 50mm to 280mm.

[0162] As a further preferred embodiment, the ratio of the size of the first housing portion 12 to the size of the second housing portion 13 along the first direction is 0.03-0.12.

[0163] By limiting the lower limit of the ratio of the dimensions of the first shell portion 12 to the second shell portion 13 along the first direction, it is ensured that the shell body 1 has a sufficiently thickened area to guarantee the structural strength of the shell body 1. At the same time, it avoids the welded area being too close to the junction of the first shell portion 12 and the second shell portion 13 due to the first shell portion 12 being too short, thereby aggravating the concentration of thermal stress. Furthermore, by limiting the upper limit of the ratio of the dimensions of the first shell portion 12 to the second shell portion 13 along the first direction, it is avoided that the first shell portion 12 is too long, resulting in structural redundancy and material waste, and that the overall weight of the shell body 1 is not excessively increased.

[0164] For example, in this embodiment, along the first direction, the ratio of the size of the first housing portion 12 to the size of the second housing portion 13 can be 0.006, 0.025, 0.053, 0.087, 0.132, 0.185, 0.241, 0.298, 0.352, 0.396, 0.43, or 0.44, or it can be a range formed by any two of the above values.

[0165] In some embodiments, the size of the first housing portion 12 along the first direction is P mm, satisfying 1.4 mm ≤ P mm ≤ 22 mm.

[0166] By limiting the lower limit of the dimension P mm of the first shell portion 12 along the first direction, it is ensured that the shell body 1 has a sufficiently thickened area to guarantee the structural strength of the shell body 1. At the same time, it avoids the welding area from being too close to the junction of the first shell portion 12 and the second shell portion 13 due to the first shell portion 12 being too short, thereby aggravating the concentration of thermal stress. Furthermore, by limiting the upper limit of the dimension P mm of the first shell portion 12 along the first direction, it is avoided that the first shell portion 12 is too long, which would lead to structural redundancy and material waste, and avoids excessively increasing the overall weight of the shell body 1.

[0167] For example, in this embodiment, the value of P mm can be 1.4 mm or 2.7 mm or 4.3 mm or 6.1 mm or 8.2 mm or 10.5 mm or 12.8 mm or 14.9 mm or 16.7 mm or 18.5 mm or 20.3 mm or 22 mm, or it can be a range formed by any two of the above values.

[0168] In some embodiments, the welding direction of the first weld line 3 is parallel to the first direction and satisfies: 0.04≤(A×E) / D≤12.

[0169] The welding direction of the first welding line 3 is along the first direction, that is, the battery cell adopts the top welding method. At this time, the direction of the penetration of the first welding line 3 is consistent with the direction of the force when the shell assembly 10 explodes. Therefore, it is necessary to appropriately increase the welding strength to improve the explosion resistance.

[0170] In some embodiments, the welding direction of the first weld line 3 is perpendicular to the first direction.

[0171] At this time, the battery cell adopts the side welding method. The direction of the penetration of the first weld line 3 is not consistent with the direction of the force when the shell assembly 10 bursts open. The welding strength requirement can be appropriately reduced to balance the process difficulty and structural reliability.

[0172] According to an embodiment of the present invention, in another aspect, a battery pack is also provided, comprising: Multiple battery cells as described above are stacked along a second direction, which is perpendicular to the large side surface of the battery cell, where the large side surface is the largest area surface of the battery cell.

[0173] By stacking multiple battery cells along the second direction to form a compact battery pack structure, the mutual support and restraint between the battery cells can be used to prevent cracking on the long side of the large side, while improving the overall impact resistance of the structure.

[0174] According to an embodiment of the present invention, in another aspect, an electrical device is also provided, comprising: The electrical device body and the battery pack as described above, which is electrically connected to the electrical device body.

[0175] In this embodiment, the electrical device can be a battery pack, electric vehicle, electric ship, aircraft, electric device, energy storage device, laptop, aerospace equipment, etc.

[0176] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Although embodiments of the present 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 present invention, and all such modifications and variations fall within the scope defined by the present invention.

Claims

1. A battery cell, characterized in that, include: A housing assembly (10) includes a housing body (1) and a cover plate (2). The housing body (1) has an opening (11) at at least one end along a first direction, and the cover plate (2) is used to block the opening (11). The housing body (1) includes a first housing portion (12) and a second housing portion (13) along the first direction. The first housing portion (12) is located closer to the opening (11) than the second housing portion (13). The thickness of the first housing portion (12) is greater than the thickness of the second housing portion (13). The thickness of the first housing portion (12) is E mm. The battery cell (4) is disposed inside the housing assembly (10); An insulating element (5) is disposed between the cover plate (2) and the battery cell (4) along the first direction, and the minimum spacing between the insulating element (5) and the inner wall of the shell body (1) is D mm; The cover plate (2) is welded to the shell body (1) near the opening (11) to form a first weld line (3), and the maximum dimension of the first weld line (3) along the first direction is A mm; It satisfies: 0.032≤(A×E) / D≤12.

2. The battery cell according to claim 1, characterized in that, The insulating element (5) includes an insulating element body (51), and the insulating element (5) has a flange structure (52) protruding from the edge of the shell body (1). The flange structure (52) extends from the insulating element body (51) along the first direction toward the side closer to the battery cell (4).

3. The battery cell according to claim 2, characterized in that, The flange structure (52) extends from the insulating body (51) along the first direction by a dimension of B mm, satisfying 2 mm ≤ B mm ≤ 10 mm.

4. The battery cell according to claim 2, characterized in that, The thickness of the flange structure (52) is C mm, which satisfies 0.05 mm ≤ C mm ≤ 1 mm.

5. The battery cell according to claim 1, characterized in that, Along the thickness direction perpendicular to the first housing portion (12), the edge of the insulating member (5) extends beyond the battery cell (4).

6. The battery cell according to claim 5, characterized in that, Along the thickness direction perpendicular to the first housing portion (12), the edge of the insulating member (5) extends beyond the cell (4) by a dimension of F mm, satisfying 0.5 mm ≤ F mm ≤ 10 mm.

7. The battery cell according to claim 1, characterized in that, The cover plate (2) includes a first cover plate surface (21) facing the cell (4) along the first direction; Along the first direction, the projection of the insulating element (5) toward the first cover surface (21) is located within the range of the first cover surface (21).

8. The battery cell according to claim 7, characterized in that, Along the thickness direction perpendicular to the first housing portion (12), the distance between the edge of the insulating member (5) and the corresponding edge of the first cover plate surface (21) is G mm, satisfying 0.2 mm ≤ G mm ≤ 4 mm.

9. The battery cell according to any one of claims 1 to 8, characterized in that, The cover plate (2) includes a main body (22) and a boss (23) extending from the main body (22) toward the side of the battery cell (4) in the first direction. The boss (23) is adapted to be inserted into the interior of the shell body (1), and in the direction perpendicular to the first direction, the boss (23) is at least partially opposite to the first shell part (12).

10. The battery cell according to claim 9, characterized in that, The first weld line (3) is at least partially formed in the area where the boss portion (23) contacts the first housing portion (12).

11. The battery cell according to claim 9, characterized in that, The boss portion (23) includes a boss sidewall (231) disposed opposite to the first housing portion (12), and the boss portion (23) also includes a first cover plate surface (21) facing the battery cell (4) in the first direction. A chamfer (232) is formed between the sidewall (231) of the boss and the surface (21) of the first cover plate, and the chamfer (232) is adapted to space at least a portion of the boss (23) from the first housing portion (12).

12. The battery cell according to claim 11, characterized in that, The maximum dimension of the chamfered portion (232) along the thickness direction perpendicular to the first housing portion (12) is J mm, satisfying 0.2 mm ≤ J mm ≤ 1.2 mm.

13. The battery cell according to claim 11, characterized in that, The maximum dimension of the chamfered portion (232) along the first direction is K mm, which satisfies 0.2 mm ≤ K mm ≤ 1.2 mm.

14. The battery cell according to claim 11, characterized in that, Along the thickness direction perpendicular to the first housing portion (12), the minimum interval between the edge of the insulating member (5) and the chamfered portion (232) is L mm, satisfying 0.1 mm ≤ L mm ≤ 3.3 mm.

15. The battery cell according to any one of claims 1 to 8, characterized in that, The cover plate (2) includes a first cover plate surface (21) facing the cell (4) along the first direction; Along the first direction, and in the direction from the cover plate (2) toward the cell (4), the end of the first housing portion (12) away from the opening (11) extends beyond the surface (21) of the first cover plate.

16. The battery cell according to claim 15, characterized in that, Along the first direction, the distance between the end of the first housing part (12) away from the opening (11) and the surface of the first cover plate (21) is H mm, which satisfies 2mm≤Hmm≤15mm.

17. The battery cell according to any one of claims 1 to 8, characterized in that, satisfy: 0.5mm ≤ A mm ≤ 2.5mm; And / or, 0.2mm ≤ E mm ≤ 1.5mm; And / or, 0.3mm≤D mm≤3.5mm.

18. The battery cell according to any one of claims 1 to 8, characterized in that, Along the first direction, and from the cover plate (2) toward the cell (4), the end face of the insulating member (5) near the cell (4) does not extend beyond the end of the first housing part (12) away from the opening (11). At this time, the following condition is met: 0.032≤(A×E) / D≤11.

5.

19. The battery cell according to any one of claims 1 to 8, characterized in that, The battery cell (4) includes a battery cell body (41) and a tab (42) extending from at least one end of the battery cell body (41); the tab (42) is disposed between the battery cell body (41) and the insulating member (5); The battery cell also includes a terminal assembly (6), which is disposed on the cover plate (2) and is electrically connected to the tab (42); Along the thickness direction perpendicular to the first housing portion (12), the minimum interval between the edge of the insulating member (5) and the tab portion (42) is M mm, satisfying 0.1 mm ≤ M mm ≤ 3.6 mm.

20. The battery cell according to any one of claims 1 to 8, characterized in that, The shell body (1) includes an adjacent first shell wall (101) and a second shell wall (102), the first shell wall (101) and the second shell wall (102) being arranged vertically; in a direction perpendicular to the first direction, the first shell wall (101) has a first inner side facing the battery cell (4), and the minimum distance between the insulating member (5) and the first inner side is D1 mm; the second shell wall (102) has a second inner side facing the battery cell (4), and the minimum distance between the insulating member (5) and the second inner side is D2 mm, wherein D1 mm is not equal to D2 mm.

21. The battery cell according to claim 20, characterized in that, The area of ​​the first shell wall (101) is greater than the area of ​​the second shell wall (102), satisfying: D1 mm > D2 mm.

22. The battery cell according to any one of claims 1 to 8, characterized in that, At least a portion of the first housing portion (12) forms the first weld line (3).

23. The battery cell according to claim 22, characterized in that, Along the first direction, the end of the first housing part (12) away from the opening (11) is spaced apart from the first welding line (3), and the spacing distance is N mm, which satisfies 0.5 mm ≤ N mm ≤ 18 mm.

24. The battery cell according to any one of claims 1 to 8, characterized in that, The first housing portion (12) includes a region of equal thickness (121) and a region of non-equal thickness (122). Along the first direction, the region of non-equal thickness (122) is disposed between the region of equal thickness (121) and the second housing portion (13).

25. The battery cell according to claim 24, characterized in that, The thickness of the non-uniform thickness region (122) gradually decreases in the direction toward the second housing portion (13).

26. The battery cell according to any one of claims 1 to 8, characterized in that, Along the direction perpendicular to the first direction, the first housing portion (12) is at least partially opposite to the battery cell (4), satisfying: 0.5mm≤D mm≤3.5mm.

27. The battery cell according to any one of claims 1 to 8, characterized in that, Along the direction perpendicular to the first direction, the projection of the first housing portion (12) and the battery cell (4) does not overlap.

28. The battery cell according to any one of claims 1 to 8, characterized in that, Along the first direction, the ratio of the size of the first housing portion (12) to the size of the second housing portion (13) is 0.006-0.

44.

29. The battery cell according to claim 28, characterized in that, Along the first direction, the size of the first housing part (12) is P mm, which satisfies 1.4 mm ≤ P mm ≤ 22 mm.

30. The battery cell according to any one of claims 1 to 8, characterized in that, The welding direction of the first weld line (3) is parallel to the first direction and satisfies: 0.04≤(A×E) / D≤12.

31. The battery cell according to any one of claims 1 to 8, characterized in that, The welding direction of the first weld line (3) is perpendicular to the first direction.

32. A battery pack, characterized in that, include: A plurality of battery cells as described in claims 1 to 31 are stacked along a second direction, the second direction being perpendicular to the large side surface of the battery cell, wherein the large side surface is the largest area surface of the battery cell.

33. An electrical appliance, characterized in that, include: The electrical device body and the battery pack as described in any one of claims 32, which is electrically connected to the electrical device body.

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