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CN-118712444-B - Secondary battery and battery pack

CN118712444BCN 118712444 BCN118712444 BCN 118712444BCN-118712444-B

Abstract

The embodiment of the application discloses a secondary battery and a battery pack, wherein the secondary battery comprises a shell, the shell comprises a side wall, a bottom wall and a first connecting part, the side wall extends along a first direction, the bottom wall is arranged on one side of the side wall in the first direction, the side wall and the bottom wall are matched to form a containing cavity, two ends of the first connecting part are respectively connected with the side wall and the bottom wall, an electrode assembly is arranged in the containing cavity, and a first insulating coating is arranged on the outer wall surface of the first connecting part, wherein the thickness of the first insulating coating is H 1 mm, and H 1 ＝0.09175+0.00294X+0.06165X 2 -0.03236X 3 and X=Rxsin (alpha/2) xsin (180-beta) are met. According to the application, the risk of dielectric breakdown of the shell is reduced, the safety performance of the shell is improved, and the safety performance of the secondary battery is further improved.

Inventors

  • YAO JUNHE

Assignees

  • 欣旺达动力科技股份有限公司

Dates

Publication Date
20260508
Application Date
20240530

Claims (9)

  1. 1. A secondary battery having a first direction, comprising: The shell comprises a side wall, a bottom wall and a first connecting part, wherein the side wall extends along the first direction, the bottom wall is arranged on one side of the side wall in the first direction, the side wall and the bottom wall are matched to form a containing cavity, two ends of the first connecting part are respectively connected with the side wall and the bottom wall, the outer wall surface of the first connecting part, which is away from the containing cavity, is an arc surface, the outer wall surface is provided with a first outer edge contour line close to the side wall and a second outer edge contour line close to the bottom wall, the first connecting part is also provided with a reference line, the reference line is connected with the first outer edge contour line and the second outer edge contour line, and the reference line is the shortest connecting line between the first outer edge contour line and the second outer edge contour line; an electrode assembly disposed in the accommodation chamber, and A first insulating coating layer provided on an outer wall surface of the first connection portion; The thickness of the first insulating coating is H 1 mm, which satisfies the following conditions ：H 1 =0.09175+0.00294X+0.06165X 2 -0.03236X 3 ,0.092mm≤H 1 ≤0.128mm;X=R×sin(α/2)×sin(180°-β),60°≤α≤90°,140°≤β≤170°; R mm is the radius of the outer wall surface, R is more than or equal to 1mm and less than or equal to 3mm, alpha is the maximum central angle corresponding to the outer wall surface, and beta is the included angle between the reference line and the bottom wall.
  2. 2. The secondary battery according to claim 1, wherein the secondary battery further has a second direction and a third direction intersecting the first direction in pairs; the side wall includes a first sub-side wall opposing each other in the first direction and a second sub-side wall opposing each other in the second direction, the first sub-side wall and the second sub-side wall being connected by the first connecting portion.
  3. 3. The secondary battery according to claim 2, wherein the case further includes a second connection portion connected to the first sub-side wall, the second sub-side wall, and the bottom wall, respectively; the secondary battery further includes a second insulating coating layer disposed on an outer surface of the second connection part; The thickness of the second insulating coating is H 2 mm, which satisfies H 2 =1.5k×H 1 ; wherein k is a variable coefficient, and k is more than or equal to 0.7 and less than or equal to 0.9.
  4. 4. The secondary battery according to claim 3, wherein the thickness H 2 mm of the second insulating coating layer is 0.097 mm≤H 2 ≤0.173 mm.
  5. 5. The secondary battery of claim 3, wherein the second insulating coating layer comprises a first sub-coating layer and a second sub-coating layer, the first sub-coating layer being disposed adjacent to the second connecting portion with respect to the second sub-coating layer; The thickness of the first sub-coating layer is H 3 mm, and the thickness of the second sub-coating layer is H 4 mm, which meets the requirement of H 2 =H 3 +H 4 .
  6. 6. The secondary battery according to claim 5, wherein the thickness H 3 mm of the first sub-coating layer is 0.092 mm≤H 3 ≤0.128 mm.
  7. 7. The secondary battery according to claim 1, further comprising a third insulating coating layer provided on outer surfaces of the side wall and the bottom wall; The thickness of the third insulating coating is H 5 mm, and H 1 /H 5 is more than or equal to 0.8 and less than or equal to 2.
  8. 8. The secondary battery according to claim 7, wherein the thickness H 5 mm of the third insulating coating layer is 0.046 mm≤H 5 ≤0.16 mm.
  9. 9. A battery pack, comprising: Case body, and The secondary battery according to any one of claims 1 to 8, which is housed in the case.

Description

Secondary battery and battery pack Technical Field The application relates to the technical field of batteries, in particular to a secondary battery and a battery pack. Background With the rapid development of mobile phones, notebook computers, electric vehicles, electric tools, etc., batteries having high capacity, long cycle life and high safety performance have been widely used and developed, and there is a great need for batteries having larger capacity, more durability and safer. The safety performance is a core performance of the battery, and the safety performance of the case of the battery is closely related to the safety performance of the secondary battery as a whole. Therefore, how to improve the safety performance of the case, and thus, the safety performance of the secondary battery, is a problem to be solved. Disclosure of Invention The embodiment of the application provides a secondary battery and a battery pack, which are used for improving the safety performance of a shell, thereby improving the safety performance of the secondary battery. In order to solve the technical problems, the embodiment of the application discloses the following technical scheme: in one aspect, there is provided a secondary battery having a first direction, comprising: The shell comprises a side wall, a bottom wall and a first connecting part, wherein the side wall extends along the first direction, the bottom wall is arranged on one side of the side wall in the first direction, the side wall and the bottom wall are matched to form a containing cavity, two ends of the first connecting part are respectively connected with the side wall and the bottom wall, the outer wall surface of the first connecting part, which is away from the containing cavity, is an arc surface, the outer wall surface is provided with a first outer edge contour line close to the side wall and a second outer edge contour line close to the bottom wall, the first connecting part is also provided with a reference line, the reference line is connected with the first outer edge contour line and the second outer edge contour line, and the reference line is the shortest connecting line between the first outer edge contour line and the second outer edge contour line; an electrode assembly disposed in the accommodation chamber, and A first insulating coating layer provided on an outer wall surface of the first connection portion; The thickness of the first insulating coating is H 1 mm, which satisfies the following conditions ：H1＝0.09175+0.00294X+0.06165X2-0.03236X3,X＝R×sin(α/2)×sin(180°-β),60°≤α≤90°,140°≤β≤170°; R mm is the radius of the outer wall surface, alpha is the maximum central angle corresponding to the outer wall surface, and beta is the included angle between the reference line and the bottom wall. In some embodiments, the thickness H 1 mm of the first insulating coating also satisfies 0.092 mm≤H 1≤0.128 mm. In some embodiments, the radius R mm of the outer wall surface is also 1 mm≤R≤3 mm. In some embodiments, the secondary battery further has a second direction and a third direction intersecting the first direction in pairs; the side wall includes a first sub-side wall opposing each other in the first direction and a second sub-side wall opposing each other in the second direction, the first sub-side wall and the second sub-side wall being connected by the first connecting portion. In some embodiments, the housing further comprises a second connecting portion connected to the first sub-side wall, the second sub-side wall, and the bottom wall, respectively; the secondary battery further includes a second insulating coating layer disposed on an outer surface of the second connection part; The thickness of the second insulating coating is H 2 mm, which satisfies H 2＝1.5k×H1; wherein k is a variable coefficient, and k is more than or equal to 0.7 and less than or equal to 0.9. In some embodiments, the thickness H 2 mm of the second insulating coating also satisfies 0.097 mm≤H 2≤0.173 mm. In some embodiments, the second insulating coating includes a first subcoat and a second subcoat, the first subcoat being disposed proximate the second connection relative to the second subcoat; The thickness of the first sub-coating layer is H 3 mm, and the thickness of the second sub-coating layer is H 4 mm, which meets the requirement of H 2＝H3+H4. In some embodiments, the thickness H 3 mm of the first subcoat also satisfies 0.092 mm≤H 3≤0.128 mm. In some embodiments, the device further comprises a third insulating coating layer arranged on the outer surfaces of the side wall and the bottom wall; The thickness of the third insulating coating is H 5 mm, and H 1/H5 is more than or equal to 0.8 and less than or equal to 2. In some embodiments, the thickness H 5 mm of the third insulating coating also satisfies 0.046 mm≤H 5≤0.16 mm. In another aspect, a battery pack is further disclosed, in some embodiments, comprising a case, and a secondary battery as set for