Battery case and battery

Abstract

This invention belongs to the field of battery technology and discloses a battery casing and a battery. The battery casing includes a casing body and a cover plate body. The cover plate body includes a closed plate and an insertion boss. The closed plate includes a body area overlapping the projection of the insertion boss, an abutment area overlapping the projection of the casing body, and a welding extension area extending beyond the casing body. A first interface is provided between the body area and the abutment area, and a second interface is provided between the welding extension area and the abutment area. The welding extension area has an outer side surface. The distance between the outer side surface and the second interface is A1, and the distance between the second interface and the first interface is A2, satisfying 0.1≤A1 / A2≤0.5. By utilizing the welding extension area to increase the effective welding area, the weld is made fuller. Furthermore, by limiting the ratio between A1 and A2, it is possible to avoid both an excessively small ratio, resulting in an incomplete weld, and an excessively large ratio, resulting in an overly protruding weld.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery casing and a battery. Background Technology

[0002] As a core energy storage component in the new energy field, the structural stability and sealing performance of batteries directly determine product reliability. A typical power battery or energy storage battery mainly consists of core components such as cells, electrolyte, battery casing, and battery cover. The battery casing is usually a cylindrical or box-shaped structure with one open end, used to house the cells and electrolyte, forming a closed energy storage space. The battery cover, as the sealing component of the casing opening, not only needs to seal the casing but also integrates functional structures such as terminals, injection holes, and explosion-proof valves. It is a key carrier for battery energy output and safety protection. Together, they constitute the battery's outer casing protection system, which has a significant impact on the overall structural strength and safety of the battery.

[0003] In the battery assembly process, after the battery cells and electrolyte are encapsulated in the battery casing, an overall seal is achieved by connecting the battery cover to the casing to prevent electrolyte leakage, prevent the intrusion of external moisture or impurities, and ensure the stability of the battery's electrochemical performance. Currently, the mainstream connection method in the industry is welding. Specifically, the battery cover is fitted and installed onto the open end of the battery casing, and then welded to form a continuous weld at the circumferential joint between the cover and the casing, thereby achieving fixation and sealing. The quality of this welding process directly affects the battery's sealing performance, structural strength, and lifespan, making it one of the key steps in the battery production process.

[0004] In existing technologies, the connection structure between the battery casing and the battery cover often adopts a circumferential flush design, meaning that after the cover is installed, its outer circumferential surface remains flush with the outer circumferential surface of the casing to ensure the regularity of the battery's appearance. This structural design results in insufficient effective welding area when welding the cover and casing, and limited space for weld formation. Consequently, on the one hand, this leads to insufficient weld filling, resulting in problems such as incomplete welds and depressions, significantly reducing the welding yield. On the other hand, incomplete welds directly reduce the weld cross-sectional area, making the connection strength between the cover and casing insufficient. This makes it unable to effectively resist vibrations, impacts, or internal pressure changes during battery use, affecting not only the structural stability of the battery but also potentially causing weld cracking and electrolyte leakage, seriously restricting the reliability and safety of battery products. Summary of the Invention

[0005] The purpose of this invention is to provide a battery casing and battery that have sufficient effective welding area, full welds, large weld cross-sectional area, high welding strength, high welding yield, and high reliability and safety.

[0006] To achieve this objective, the present invention adopts the following technical solution: On one hand, a battery housing is provided, the battery housing comprising: The outer casing body has a receiving cavity, and the receiving cavity has an installation opening on at least one side; The cover plate body corresponds one-to-one with the mounting opening and is welded to the outer shell body to form a welded part. The cover plate body includes a closed plate and an insertion boss. The insertion boss is located on the side of the closed plate facing the outer shell body and is inserted into the accommodating cavity. The closed plate includes a body area, an abutment area, and a welding extension area. The body area, the abutment area, and the welding extension area are distributed in concentric circles from the inside to the outside. The projection of the body area and the insertion boss on the closed plate along a first direction overlaps. The projection of the abutment area and the outer shell body on the closed plate along the first direction overlaps. The area of ​​the closed plate that extends beyond the outer shell body perpendicular to the first direction is the welding extension area. A first interface is provided between the body area and the abutment area. A second interface is provided between the welding extension area and the abutment area, surrounding the outside of the first interface. The side of the welding extension area away from the abutment area has an outer side surface surrounding the outside of the second interface. The first direction is the thickness direction of the cover plate body. Perpendicular to the first direction, the distance between the outer side and the second interface is A1, and the distance between the second interface and the first interface is A2, and satisfies 0.1≤A1 / A2≤0.5.

[0007] Optionally, the distance A1 between the outer side and the second interface in the same direction along the perpendicular direction shall satisfy 0.03mm≤A1≤0.15mm.

[0008] Optionally, the thickness of the body area and the abutment area along the first direction is both H1, and the thickness of the welding extension area along the first direction is H2. When H2≤H1, the cover plate body and the outer shell body are butt welded, and when H2>H1, the cover plate body and the outer shell body are through welded.

[0009] Optionally, when the relationship between the thickness dimension H2 of the welding extension area along the first direction and the thickness dimension H1 of the body area and the abutment area along the first direction is H2≤H1, and 0.4≤H2 / H1≤1 is satisfied.

[0010] Optionally, the welding extension area includes a first lower surface facing the housing body and a first upper surface away from the housing body, and the abutment area includes a second lower surface facing the housing body and a second upper surface away from the housing body. When H2 < H1, the first upper surface and the second upper surface are not coplanar, and / or, the first lower surface and the second lower surface are not coplanar.

[0011] Optionally, when the relationship between the thickness H2 of the welding extension area along the first direction and the thickness H1 of the body area and the abutment area along the first direction is H2 > H1, and satisfies 1 < H2 / H1 ≤ 1.8.

[0012] Optionally, the area of ​​the abutment area along the first direction toward the outer shell body is S1, and the area of ​​the welding extension area along the first direction toward the outer shell body is S2, and satisfies 0.6≤S1 / (S1+S2)≤0.9.

[0013] Optionally, the welding extension area includes a first upper surface away from the outer shell body, and the height dimension of the welding part protruding from the first upper surface along the first direction is L1, and L1≤150μm.

[0014] Optionally, the height of the welded portion protruding from the outer side along the direction perpendicular to the first direction is L2, and L2 ≤ 200 μm.

[0015] On the other hand, a battery is provided, the battery including an electrode assembly and a battery housing as described in any of the above claims, the electrode assembly being disposed within the battery housing.

[0016] The beneficial effects of this invention are: This invention provides a battery casing that utilizes a welding extension area on the outermost ring of the cover plate body to increase the effective welding area, resulting in a fuller weld and increased welding cross-sectional area. This enhances welding strength and improves welding yield. Furthermore, the ratio of the distance A1 between the outer surface of the welding extension area and the second interface between the welding extension area and the abutment area, and the distance A2 between the second interface and the first interface between the main body area and the abutment area, is limited to satisfy 0.1 ≤ A1 / A2 ≤ 0.5. This avoids both excessively small ratios, which would result in a narrow welding extension area, insufficient effective welding area, and an incomplete weld with sharp edges, and excessively large ratios, which would cause the weld to protrude excessively, resulting in raised edges and affecting subsequent assembly operations.

[0017] The present invention also provides a battery that, by applying the above-mentioned battery casing, can not only effectively resist the cracking of the welded parts caused by vibration, impact or internal pressure changes during battery use, thus having high structural strength, but also avoid electrolyte leakage, thus having high sealing performance, thereby improving the reliability and safety of the battery. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the partitioning of the enclosed plate in the battery casing provided by the present invention; Figure 2 This is a schematic diagram of the welding between the cover plate body and the outer casing body in the battery casing provided by the present invention; Figure 3 yes Figure 2 Enlarged view of the structure of section A; Figure 4 This is a schematic diagram of the assembly of the outer casing body and the cover plate body in the battery casing provided by the present invention when H1=H2; Figure 5 This is a schematic diagram of the assembly of the outer casing body and the cover plate body in the battery casing provided by the present invention when H2 < H1; Figure 6 This is a schematic diagram of the assembly of the outer casing body and the cover plate body in the battery casing provided by the present invention when H2 < H1; Figure 7 This is a schematic diagram of the assembly of the outer casing body and the cover plate body in the battery casing provided by the present invention when H2 < H1; Figure 8 This is a schematic diagram of the assembly of the outer casing body and the cover plate body in the battery casing provided by the present invention when H2 > H1.

[0019] In the picture: 100. Welding section; 1. Outer shell; 2. Cover plate body; 21. Enclosed plate body; 211. Body area; 212. Abutment area; 2121. Second lower surface; 2122. Second upper surface; 213. Welding extension area; 2131. First lower surface; 2132. First upper surface; 214. First interface; 215. Second interface; 216. Outer surface; 22. Insertion boss. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0024] In existing technologies, the connection structure between the battery casing and the battery cover often adopts a circumferential flush design, meaning that the outer circumference of the cover is flush with the outer circumference of the casing after installation to ensure the regularity of the battery's appearance. This structural design results in insufficient effective welding area when welding the cover and casing, and limited space for weld formation. Consequently, on the one hand, this leads to insufficient weld filling, resulting in incomplete welds, depressions, and other problems, significantly reducing the welding yield. On the other hand, incomplete welds directly reduce the weld cross-sectional area, making the connection strength between the cover and casing insufficient. This makes it unable to effectively resist vibrations, impacts, or internal pressure changes during battery use, affecting not only the structural stability of the battery but also potentially causing weld cracking and electrolyte leakage, seriously restricting the reliability and safety of battery products.

[0025] Therefore, in order to increase the effective welding area, make the weld more complete, thereby increasing the welding cross-sectional area, improving the welding strength and welding yield, this embodiment provides a battery casing.

[0026] likeFigures 1 to 8 As shown, the battery casing includes a casing body 1 and a cover plate body 2. The casing body 1 has an accommodating cavity, and at least one side of the accommodating cavity has an installation opening. The cover plate body 2 corresponds to the installation opening and is welded to the casing body 1 to form a welded part 100. The cover plate body 2 includes a closed plate 21 and an insertion boss 22. The insertion boss 22 is located on the side of the closed plate 21 facing the casing body 1 and is inserted into the accommodating cavity. The closed plate 21 includes a body area 211, an abutment area 212, and a welding extension area 213. The body area 211, the abutment area 212, and the welding extension area 213 are distributed in concentric circles from the inside to the outside. The projections of the body area 211 and the insertion boss 22 onto the closed plate 21 along a first direction overlap. The abutment area 212 overlaps with the casing body 1 along the first direction. The projections on the closed plate 21 overlap. The area of ​​the closed plate 21 that extends beyond the outer shell body 1 in the first direction is the welding extension area 213. A first interface 214 is provided between the body area 211 and the abutment area 212. A second interface 215 is provided between the welding extension area 213 and the abutment area 212, surrounding the outside of the first interface 214. An outer side surface 216 is provided on the side of the welding extension area 213 away from the abutment area 212, surrounding the outside of the second interface 215. The first direction is the thickness direction of the cover plate body 2. The distance between the outer side surface 216 and the second interface 215 is A1, and the distance between the second interface 215 and the first interface 214 is A2, and 0.1≤A1 / A2≤0.5 is satisfied.

[0027] The battery casing has a welding extension area 213 on the outermost ring of the closed plate 21 of the cover plate body 2, which extends beyond the casing body 1. This welding extension area 213 increases the effective welding area, making the welded part 100 fuller and increasing the welding cross-sectional area. This enhances the welding strength and improves the welding yield. Furthermore, the ratio between the outer side surface 216 of the welding extension area 213 and the second interface 215 between the welding extension area 213 and the abutment area 212, and the ratio between the second interface 215 and the first interface 214 between the body area 211 and the abutment area 212, is limited to 0.1≤A1 / A2≤0.5. This avoids the ratio being too small, making the welding extension area 213 too narrow, resulting in insufficient increased effective welding area, an incomplete welded part 100, and sharp edges. On the other hand, it avoids the ratio being too large, causing the welded part 100 to protrude too much, resulting in bulging edges and affecting subsequent assembly operations.

[0028] The ratio between the spacing dimension A1 between the outer surface 216 and the second interface 215 and the spacing dimension A2 between the second interface 215 and the first interface 214 can be between 0.1 and 0.5, any value or any range between two values, such as 0.1, 0.2, 0.3, 0.4, 0.5, etc.

[0029] Optionally, such as Figure 1 As shown, the distance A1 between the outer surface 216 and the second interface 215 along the vertical first direction satisfies 0.03mm≤A1≤0.15mm. Since the distance between the outer surface 216 and the second interface 215 is essentially the width of the welding extension area 213, by specifically limiting the distance A1 between the outer surface 216 and the second interface 215 to satisfy 0.03mm≤A1≤0.15mm, the width of the extension area is clearly defined. On the one hand, this avoids the distance A1 between the outer surface 216 and the second interface 215 being too small, resulting in the welding extension area 213 being too narrow, which would lead to insufficient increased effective welding area, an incomplete weld 100, and the appearance of sharp edges. On the other hand, it avoids the distance A1 between the outer surface 216 and the second interface 215 being too large, resulting in the welding extension area 213 being too wide, which would cause the weld 100 formed after welding to be too protruding, resulting in a raised edge, which would easily be torn by the protruding weld 100 when the protective film is wrapped subsequently.

[0030] Furthermore, by combining the ratio between the spacing dimension A1 between the outer side 216 and the second interface 215 and the spacing dimension A2 between the second interface 215 and the first interface 214, the width of the abutment area 212 can be deduced. Since the projection of the abutment area 212 and the outer shell body 1 onto the closed plate 21 is the same as the wall thickness of the outer shell body 1, the width of the abutment area 212 can be essentially equivalent to the wall thickness of the outer shell body 1. Therefore, by deducing the width of the abutment area 212, the most suitable wall thickness range of the outer shell body 1 under the current width of the welding extension area 213 can be determined, thereby ensuring the strength and welding effect after welding.

[0031] The distance A1 between the outer surface 216 and the second interface 215 along the vertical first direction can be any value between 0.03mm and 0.15mm or any range between two values, such as 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, etc.

[0032] In order to verify the influence of the ratio between the spacing dimension A1 between the outer surface 216 and the second interface 215 and the spacing dimension A2 between the second interface 215 and the first interface 214 on the welding effect, experiments were conducted as shown in Table 1.

[0033] Table 1 A comparison of Examples 1 to 10 with Comparative Examples 1 to 2 shows that when the ratio of the distance A1 between the outer surface 216 and the second interface 215 to the distance A2 between the second interface 215 and the first interface 214 is less than the minimum value in the range 0.1 ≤ A1 / A2 ≤ 0.5, the welding extension area 213 is too narrow, resulting in insufficient increased effective welding area, and the welded part 100 is not full, with sharp edges. When the ratio of the distance A1 between the outer surface 216 and the second interface 215 to the distance A2 between the second interface 215 and the first interface 214 is greater than the maximum value in the range 0.1 ≤ A1 / A2 ≤ 0.5, the welded part 100 is too protruding, with bulging edges, affecting subsequent assembly operations.

[0034] Optionally, the thickness dimension of the body area 211 and the abutment area 212 along the first direction is H1, and the thickness dimension of the welding extension area 213 along the first direction is H2. When H2≤H1, the cover plate body 2 and the outer shell body 1 are butt welded, and when H2>H1, the cover plate body 2 and the outer shell body 1 are through welded.

[0035] When the relationship between the thickness H2 of the welding extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is H2≤H1, the welding extension area 213 does not block the joint between the closed plate 21 and the outer shell body 1. At this time, the cover plate body 2 and the outer shell body 1 can be connected by butt welding. However, when the relationship between the thickness H2 of the welding extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is H2>H1, the welding extension area 213 will block the joint between the closed plate 21 and the outer shell body 1. The cover plate body 2 and the outer shell body 1 cannot be connected by butt welding. In this case, the connection between the cover plate body 2 and the outer shell body 1 can be achieved by through welding.

[0036] Optionally, such as Figures 4 to 7As shown, when the thickness H2 of the weld extension area 213 along the first direction is related to the thickness H1 of the body area 211 and the abutment area 212 along the first direction, H2 ≤ H1, and satisfies 0.4 ≤ H2 / H1 ≤ 1. Since the relationship between the thickness H2 of the weld extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is H2 ≤ H1, a butt weld is used. If the thickness H2 of the weld extension area 213 is greater than the thickness H1 of the body area 211 and the abutment area 212, a through weld is used. Therefore, the case where the thickness H2 of the weld extension area 213 is greater than the thickness H1 of the body area 211 and the abutment area 212 is not discussed here. Thus, it can be seen that... By limiting the ratio between the thickness H2 of the welding extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 to satisfy 0.4≤H2 / H1≤1, the essence is to limit the minimum value of the thickness H2 of the welding extension area 213, so as to avoid the thickness H2 of the welding extension area 213 being too small relative to the thickness H1 of the body area 211 and the abutment area 212, which would result in the welded part 100 being incomplete and the welded part 100 having sharp edges after welding.

[0037] The ratio between the thickness H2 of the welding extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 can be any value between 0.4 and 1 or any two values, such as 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.

[0038] Optionally, such as Figures 5 to 7 As shown, the welding extension area 213 includes a first lower surface 2131 facing the outer shell body 1 and a first upper surface 2132 away from the outer shell body 1. The abutment area 212 includes a second lower surface 2121 facing the outer shell body 1 and a second upper surface 2122 away from the outer shell body 1. When H2 < H1, the first upper surface 2132 and the second upper surface 2122 are not coplanar, and / or, the first lower surface 2131 and the second lower surface 2121 are not coplanar.

[0039] When the thickness H2 of the weld extension zone 213 is less than H1, and the thickness H1 of the body zone 211 and the abutment zone 212 are related, the weld extension zone 213 and the abutment zone 212 will form three different structural forms, namely: like Figure 5 As shown, in the first case, the first upper surface 2132 and the second upper surface 2122 are not coplanar, but the first lower surface 2131 and the second lower surface 2121 are coplanar. In this case, the enclosed plate 21 will form a recessed platform on the surface away from the outer shell body 1, thereby forming an avoidance space and reducing the probability of the outer edge of the cover plate body 2 being bumped.

[0040] likeFigure 6 As shown, in the second case, the first upper surface 2132 and the second upper surface 2122 are coplanar, but the first lower surface 2131 and the second lower surface 2121 are not coplanar. In this case, the closed plate 21 will form a countersunk platform on the surface facing the outer shell body 1. Therefore, when welding the closed plate 21 and the outer shell body 1, more welding material needs to be filled at the junction to improve the welding strength.

[0041] like Figure 7 As shown, in the third type, the first upper surface 2132 and the second upper surface 2122 are not coplanar, and the first lower surface 2131 and the second lower surface 2121 are also not coplanar. In this case, not only can a clearance space be formed to reduce the probability of collisions on the outer edge of the cover plate body 2, but also the welding strength can be improved by filling more welding material at the junction.

[0042] In this embodiment, the surface of the body region 211 facing away from the outer shell body 1 is coplanar with the second upper surface 2122, and the surface of the body region 211 facing the outer shell body 1 is coplanar with the second lower surface 2121.

[0043] In order to verify the influence of the ratio between the thickness H2 of the weld extension zone 213 and the thickness H1 of the body zone 211 and the abutment zone 212 on the welding effect when the relationship between H2≤H1 is H2≤H1, experiments were conducted as shown in Table 2.

[0044] Table 2 A comparison of Examples 11 to 20 with Comparative Examples 3 to 4 shows that when the relationship between the thickness H2 of the weld extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is H2≤H1, if the ratio between the thickness H2 of the weld extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is less than the minimum value of the range 0.4≤H2 / H1≤1, then the thickness H2 of the weld extension area 213 is too small relative to the thickness H1 of the body area 211 and the abutment area 212, resulting in the welded part 100 being incomplete after welding, and sharp edges appearing on the edge of the welded part 100.

[0045] Optionally, such as Figure 8As shown, when the thickness H2 of the weld extension area 213 along the first direction is related to the thickness H1 of the body area 211 and the abutment area 212 along the first direction, H2 > H1, and satisfies 1 < H2 / H1 ≤ 1.8. Since if the thickness H2 of the weld extension area 213 is greater than the thickness H1 of the body area 211 and the abutment area 212, it is a through weld. When the thickness H2 of the weld extension area 213 is related to the thickness H1 of the body area 211 and the abutment area 212, H2 ≤ H1, butt weld is used. Therefore, the case where the thickness H2 of the weld extension area 213 is related to the thickness H1 of the body area 211 and the abutment area 212 is not discussed here. Thus, it can be seen that by adjusting the thickness of the weld extension area 213... The ratio between the thickness dimension H2 and the thickness dimension H1 of the body region 211 and the abutment region 212 is limited to satisfy 1 < H2 / H1 ≤ 1.8. Essentially, this is to limit the maximum value of the thickness dimension H2 of the welding extension region 213, so as to avoid the thickness dimension H2 of the welding extension region 213 being too large relative to the thickness dimension H1 of the body region 211 and the abutment region 212. This would result in the welded part 100 being full after welding, but the heat-affected zone being too large, which would not only lead to increased power, but also cause the welded part 100 to be too protruding after welding, thus producing a flange protrusion.

[0046] The ratio between the thickness H2 of the welding extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 can be any value between 1 and 1.8 or any two values, such as 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, etc.

[0047] In order to verify the influence of the ratio between the thickness H2 of the weld extension zone 213 and the thickness H1 of the body zone 211 and the abutment zone 212 on the welding effect when the relationship between H2 and H1 is H2 > H1, experiments were conducted as shown in Table 3.

[0048] Table 3 A comparison of Examples 21 to 30 with Comparative Examples 5 to 6 shows that when the relationship between the thickness H2 of the weld extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is H2 > H1, if the ratio between the thickness H2 of the weld extension area 213 and the thickness H1 of the body area 211 and the abutment area 212 is greater than the maximum value of the range 1 < H2 / H1 ≤ 1.8, the welded part 100 after welding will be full, but the heat-affected zone generated will be too large. This will not only lead to an increase in power, but also cause the welded part 100 after welding to be too protruding, resulting in a flange protrusion.

[0049] Optionally, such as Figure 1 As shown, the area of ​​the abutment area 212 facing the outer shell body 1 is S1, and the area of ​​the welding extension area 213 facing the outer shell body 1 along the first direction is S2, satisfying 0.6≤S1 / (S1+S2)≤0.9. By limiting the relationship between the area S1 of the abutment area 212 facing the outer shell body 1 and the area S2 of the welding extension area 213 facing the outer shell body 1, ensuring that 0.6≤S1 / (S1+S2)≤0.9, this avoids two problems: firstly, the abutment area 212 being too small, resulting in the welding extension area 213 being too large, causing the closed plate 21 to protrude too much from the outer shell body 1, leading to an excessively protruding welded part 100 after welding, resulting in a raised edge; secondly, it avoids the abutment area 212 being too large, resulting in the welding extension area 213 being too small, causing the area of ​​the closed plate 21 protruding too little from the outer shell body 1, resulting in an incomplete welded part 100 after welding, poor welding strength, and a tendency to develop sharp edges.

[0050] The relationship between the area dimension S1 of the contact area 212 facing the outer shell body 1 and the area dimension S2 of the welding extension area 213 facing the outer shell body 1 can be any value between 0.6 and 0.9 or a range between any two values, such as 0.6, 0.7, 0.8, 0.9, etc.

[0051] In order to verify the relationship between the area size S1 of the contact area 212 facing the outer shell body 1 and the area size S2 of the welding extension area 213 facing the outer shell body 1, and the influence on the welding effect, experiments were conducted as shown in Table 4.

[0052] Table 4 A comparison of Examples 31 to 40 with Comparative Examples 7 to 8 reveals that when the relationship between the area S1 of the abutment area 212 facing the outer shell body 1 and the area S2 of the welding extension area 213 facing the outer shell body 1 is less than the minimum value of the range 0.6 ≤ S1 / (S1+S2) ≤ 0.9, the abutment area 212 is too small, resulting in the welding extension area 213 being too large. This causes the closed plate 21 to protrude too much from the outer shell body 1, leading to the welded part 100 being too large after welding. The protrusion results in a flanged protrusion. When the relationship between the area S1 of the abutment area 212 facing the outer shell body 1 and the area S2 of the welding extension area 213 facing the outer shell body 1 is greater than the maximum value of the range 0.6≤S1 / (S1+S2)≤0.9, the abutment area 212 is too large, resulting in the welding extension area 213 being too small. This makes the area of ​​the closed plate 21 protruding from the outer shell body 1 too small, resulting in an incomplete welded part 100 after welding, poor welding strength, and easy appearance of sharp edges.

[0053] Optionally, such as Figure 3 As shown, the welding extension area 213 includes a first upper surface 2132 facing away from the outer shell body 1. The welding part 100 protrudes from the first upper surface 2132 in a first direction by a height dimension L1, and satisfies L1≤150μm. By limiting the height dimension L1 of the welding part 100 protruding from the first upper surface 2132, the welding part 100 is prevented from protruding too much from the first upper surface 2132, which would affect subsequent assembly operations.

[0054] Optionally, such as Figure 3 As shown, the height dimension of the welding part 100 protruding from the outer side surface 216 along the first direction is L2, and L2 ≤ 200 μm. By limiting the height dimension L2 of the welding part 100 protruding from the outer side surface 216, the welding part 100 is prevented from protruding too much from the outer side surface 216, which would affect subsequent assembly operations.

[0055] In this embodiment, a battery is also provided, comprising an electrode assembly and a battery casing, wherein the electrode assembly is disposed within the battery casing. By employing the aforementioned battery casing, this battery not only effectively resists cracking of the welded portion 100 caused by vibration, impact, or internal pressure changes during battery use, thus exhibiting high structural strength, but also prevents electrolyte leakage, providing high sealing performance, thereby improving the reliability and safety of the battery.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery casing, characterized in that, The battery casing includes: The outer shell body (1) is provided with a receiving cavity, and the receiving cavity is provided with an installation opening on at least one side; The cover plate body (2) corresponds one-to-one with the mounting opening and is welded to the outer shell body (1) to form a welded part (100). The cover plate body (2) includes a closed plate (21) and a plug-in boss (22). The plug-in boss (22) is located on the side of the closed plate (21) facing the outer shell body (1) and is inserted into the accommodating cavity. The closed plate (21) includes a body area (211), an abutment area (212), and a welding extension area (213). The body area (211), the abutment area (212), and the welding extension area (213) are distributed in concentric circles from the inside to the outside. The projections of the body area (211) and the plug-in boss (22) on the closed plate (21) along a first direction overlap. The abutment area (212) overlaps with the projection of the outer shell body (1) onto the closed plate (21) along the first direction. The area of ​​the closed plate (21) that extends beyond the outer shell body (1) perpendicular to the first direction is the welding extension area (213). A first interface (214) is provided between the body area (211) and the abutment area (212). A second interface (215) is provided between the welding extension area (213) and the abutment area (212) surrounding the outside of the first interface (214). An outer side (216) surrounding the outside of the second interface (215) is provided on the side of the welding extension area (213) away from the abutment area (212). The first direction is the thickness direction of the cover plate body (2). Perpendicular to the first direction, the distance between the outer side (216) and the second interface (215) is A1, and the distance between the second interface (215) and the first interface (214) is A2, and satisfies 0.1≤A1 / A2≤0.

5.

2. The battery casing according to claim 1, characterized in that, The distance A1 between the outer side surface (216) and the second interface (215) along the direction perpendicular to the first direction satisfies 0.03mm≤A1≤0.15mm.

3. The battery casing according to claim 1, characterized in that, The thickness of the body area (211) and the abutment area (212) along the first direction is H1, and the thickness of the welding extension area (213) along the first direction is H2. When H2≤H1, the cover plate body (2) and the outer shell body (1) are butt welded. When H2>H1, the cover plate body (2) and the outer shell body (1) are through welded.

4. The battery casing according to claim 3, characterized in that, When the thickness dimension H2 of the welding extension area (213) along the first direction is H2≤H1 and the thickness dimension H1 of the body area (211) and the abutment area (212) along the first direction is satisfied, and 0.4≤H2 / H1≤1 is satisfied.

5. The battery casing according to claim 3, characterized in that, The welding extension area (213) includes a first lower surface (2131) facing the outer shell body (1) and a first upper surface (2132) facing away from the outer shell body (1). The abutment area (212) includes a second lower surface (2121) facing the outer shell body (1) and a second upper surface (2122) facing away from the outer shell body (1). When H2 < H1, the first upper surface (2132) and the second upper surface (2122) are not coplanar, and / or, the first lower surface (2131) and the second lower surface (2121) are not coplanar.

6. The battery casing according to claim 3, characterized in that, When the thickness dimension H2 of the welding extension area (213) along the first direction is related to the thickness dimension H1 of the body area (211) and the abutment area (212) along the first direction, H2 > H1, and satisfies 1 < H2 / H1 ≤ 1.

8.

7. The battery casing according to claim 1, characterized in that, The area of ​​the contact area (212) facing the outer shell body (1) along the first direction is S1, and the area of ​​the welding extension area (213) facing the outer shell body (1) along the first direction is S2, and satisfies 0.6≤S1 / (S1+S2)≤0.

9.

8. The battery casing according to claim 1, characterized in that, The welding extension area (213) includes a first upper surface (2132) facing away from the outer shell body (1), and the height dimension of the welding part (100) protruding from the first upper surface (2132) along the first direction is L1, and L1≤150μm.

9. The battery casing according to claim 1, characterized in that, The height dimension of the welded part (100) protruding from the outer side surface (216) along the direction perpendicular to the first direction is L2, and L2≤200μm.

10. A battery, characterized in that, The battery includes an electrode assembly and a battery casing as described in any one of claims 1-9, wherein the electrode assembly is disposed within the battery casing.

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