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EP-4742423-A1 - END COVER ASSEMBLY, ENERGY STORAGE DEVICE, AND ENERGY STORAGE SYSTEM

EP4742423A1EP 4742423 A1EP4742423 A1EP 4742423A1EP-4742423-A1

Abstract

An end cover assembly (100), an energy-storage apparatus (200), and an energy-storage system (300) are provided in the disclosure. A first lower plastic member (31), a first terminal post (41), and a first connector (61) are included. The first terminal post (40) penetrates through the first lower plastic member (31) and abuts against a first surface (3111) thereof. The first terminal post (40) includes a first terminal-post welding portion (611) and includes a first inner, middle, and outer welding rings that are arranged in sequence and spaced apart thereon. Centerlines of the first inner, middle, and outer welding rings coincide with one another. The first terminal-post welding portion (611) is electrically connected to the first terminal post (41) via the first inner, middle, and outer welding rings. The first inner welding ring (613) has a first welding stress point (6131), the first middle welding ring (614) has a second welding stress point (6141), and the first outer welding ring (615) has a third welding stress point (6151). Any two stress points of the first, second, and third welding stress points are arranged in a staggered manner.

Inventors

  • LI, MAOSONG
  • TAN, Jiben

Assignees

  • Shenzhen Hithium Energy Storage Technology Co., Ltd.
  • Xiamen Hithium Energy Storage Technology Co., Ltd.

Dates

Publication Date
20260513
Application Date
20230712

Claims (15)

  1. An end cover assembly, comprising: a first lower plastic member having a first surface facing an electrode assembly; a first terminal post penetrating through the first lower plastic member; and a first connector, wherein the first connector abuts against the first surface, the first connector is electrically connectable between the first terminal post and the electrode assembly, the first connector comprises a first terminal-post welding portion, and comprises a first inner welding ring, a first middle welding ring, and a first outer welding ring disposed on the first terminal-post welding portion; wherein a centerline of the first inner welding ring, a centerline of the first middle welding ring, and a centerline of the first outer welding ring coincide with one another, the first middle welding ring is located outside the first inner welding ring and spaced apart from the first inner welding ring, the first outer welding ring is located outside the first middle welding ring and spaced apart from the first middle welding ring, and the first terminal-post welding portion is electrically connected to the first terminal post via the first inner welding ring, the first middle welding ring, and the first outer welding ring; and wherein the first inner welding ring has a first welding stress point, the first middle welding ring has a second welding stress point, and the first outer welding ring has a third welding stress point; in a radial direction of the first outer welding ring, any two stress points of the first welding stress point, the second welding stress point, and the third welding stress point are arranged in a staggered manner.
  2. The end cover assembly according to claim 1, wherein a distance between the first inner welding ring and the first middle welding ring is less than a distance between the first middle welding ring and the first outer welding ring.
  3. The end cover assembly according to claim 1 or 2, wherein the first terminal post comprises a first post body and a first flange portion, wherein the first post body protrudes from the first flange portion, a first terminal-post through hole is defined on the first lower plastic member, wherein the first terminal-post through hole comprises a first hole and a second hole communicating with each other, an aperture size of the second hole is greater than an aperture size of the first hole, a portion of the first post body is located in the first hole, the first flange portion is located in the second hole, a surface of the first flange portion facing away from the first post body is flush with the first surface, and the first flange portion is fixedly connected to the first connector by the first inner welding ring, the first middle welding ring, and the first outer welding ring.
  4. The end cover assembly according to claim 3, wherein an area enclosed by the first outer welding ring on the first terminal-post welding portion is larger than an area of an orthographic projection of the first post body on the first terminal-post welding portion.
  5. The end cover assembly according to claim 3, wherein an orthographic projection of the first post body on the first terminal-post welding portion covers both an orthographic projection of the first inner welding ring on the first terminal-post welding portion and an orthographic projection of the first middle welding ring on the first terminal-post welding portion.
  6. The end cover assembly according to claim 3, wherein the first connector further comprises a first array indentation disposed on a surface of the first terminal-post welding portion facing away from the first lower plastic member, wherein the first inner welding ring, the first middle welding ring, and the first outer welding ring are all located within a region enclosed by the first array indentation on the first terminal-post welding portion.
  7. The end cover assembly according to claim 6, wherein a distance between an outer edge of the first outer welding ring and an outer edge of the first array indentation is greater than or equal to 2mm.
  8. The end cover assembly according to claim 6, wherein a region enclosed by the first array indentation on the first terminal-post welding portion is larger than an orthographic projection of the first flange portion on the first terminal-post welding portion.
  9. The end cover assembly according to claim 1 or 2, wherein the first connector further comprises two first tab-welding-portions, wherein the two first tab-welding-portions are connected to a same side of the first terminal-post welding portion, and are spaced apart from each other in a width direction of the end cover assembly; and the first terminal-post welding portion and the two first tab-welding-portions cooperatively define an opening, the first lower plastic member comprises a first lower plastic body and a flow-splitting portion, wherein the flow-splitting portion protrudes from the first surface of the first lower plastic body, and a portion of the flow-splitting portion is located in the opening.
  10. The end cover assembly according to claim 9, wherein the first lower plastic member further comprises a first barrier wall, wherein the first barrier wall is annularly disposed on a periphery of the first lower plastic body in a circumferential direction of the first lower plastic body, the first barrier wall protrudes from the first surface of the first lower plastic body, the first barrier wall and the first lower plastic body cooperatively define a first cavity, and the first cavity is configured to accommodate a portion of the first connector.
  11. The end cover assembly according to claim 1 or 2, wherein in a length direction of the end cover assembly, a width W 1 of the first terminal-post welding portion satisfies: 24mm ≤ W 1 ≤ 38mm.
  12. The end cover assembly according to claim 9, wherein in the width direction of the end cover assembly, a width W2 of each of the two first tab-welding-portions satisfies: 14mm ≤ W 2 ≤ 27mm.
  13. The end cover assembly according to claim 9, wherein in a length direction of the end cover assembly, a distance W 3 between the first terminal-post welding portion and the flow-splitting portion satisfies: 0.5mm ≤ W 3 ≤ 2.5mm.
  14. An energy-storage apparatus, comprising an electrode assembly and the end cover assembly according to any one of claims 1 to 13, wherein the electrode assembly is electrically connected to the end cover assembly.
  15. An energy-storage system, comprising the energy-storage apparatus according to claim 14.

Description

TECHNICAL FIELD The present disclosure relates to the field of energy-storage technology, and in particular, to an end cover assembly, an energy-storage apparatus, and an energy-storage system. BACKGROUND With the development of clean energy, an increasing number of devices employ energy-storage apparatuses such as secondary batteries as their primary power source. In an energy storage apparatus, a connector needs to be disposed between terminal posts and an electrode assembly to achieve electrical connection therebetween. Currently, the performance of electrical connection between the terminal posts and the electrode assembly is relatively poor, which can easily lead to the failure of a secondary battery during use, thereby affecting the service life of the battery. SUMMARY An end cover assembly, an energy-storage apparatus, and an energy-storage system are provided in embodiments of the disclosure, which can avoid failure of a secondary battery and impact on the service life of the secondary battery due to poor performance of electrical connection between a terminal post and an electrode assembly. In a first aspect, an end cover assembly is provided in the disclosure. The end cover assembly includes a first lower plastic member having a first surface facing an electrode assembly, a first terminal post penetrating through the first lower plastic member, and a first connector. The first connector abuts against the first surface. The first connector is electrically connectable between the first terminal post and the electrode assembly. The first connector includes a first terminal-post welding portion, and includes a first inner welding ring, a first middle welding ring, and a first outer welding ring disposed on the first terminal-post welding portion. A centerline of the first inner welding ring, a centerline of the first middle welding ring, and a centerline of the first outer welding ring coincide with one another. The first middle welding ring is located outside the first inner welding ring and spaced apart from the first inner welding ring. The first outer welding ring is located outside the first middle welding ring and spaced apart from the first middle welding ring, and the first terminal-post welding portion is electrically connected to the first terminal post via the first inner welding ring, the first middle welding ring, and the first outer welding ring. The first inner welding ring has a first welding stress point, the first middle welding ring has a second welding stress point, and the first outer welding ring has a third welding stress point. In a radial direction of the first outer welding ring, any two stress points of the first welding stress point, the second welding stress point, and the third welding stress point are arranged in a staggered manner. It may be understood that, the first welding stress point may indicate a welding start point (or end point) of the first inner welding ring, and the first welding stress point may be a pit formed by the melting of the first connector under heat. The second welding stress point may indicate a welding start point (or end point) of the first middle welding ring, and the second welding stress point may be a pit formed by the melting of the first connector under heat. The third welding stress point may indicate a welding start point (or end point) of the first outer welding ring, and the third welding stress point may be a pit formed by the melting of the first connector under heat. By staggering the welding start points (end points) of the three welding rings in the radial direction of the welding rings, concentration of the welding start points (end points) in the same radius direction is avoided, which prevents insufficient structural strength of the first connector caused by melting of the first connector. Furthermore, it effectively mitigates warping of the first connector due to stress concentration. As a result, the performance of electrical connection between the first terminal post and the electrode assembly is improved, contributing to enhanced service life and operational reliability of an energy-storage apparatus equipped with the end cover assembly. In a possible embodiment, a distance between the first inner welding ring and the first middle welding ring is less than a distance between the first middle welding ring and the first outer welding ring. It may be understood that, the first inner welding ring and the first middle welding ring primarily serve as the current path region between the first terminal post and the first connector. By setting a relatively small distance between the first inner welding ring and the first middle welding ring, a surface connection structure is easily formed, avoiding the formation of parasitic capacitance between the first inner welding ring and the first middle welding ring, thereby reducing potential current loss. The first outer welding ring primarily serves as a reinforcement ring for the connect