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EP-4738548-A1 - SECONDARY BATTERY AND METHOD FOR MANUFACTURING THE SAME

EP4738548A1EP 4738548 A1EP4738548 A1EP 4738548A1EP-4738548-A1

Abstract

A secondary battery includes an electrode assembly including a positive electrode, a separator, and a negative electrode; a case body accommodating the electrode assembly and having an open surface; a cover coupled to the open surface of the case body; and a positive electrode terminal connected to the positive electrode and coupled to a surface of the case body. The positive electrode terminal includes a fastening member extending into a through hole in the surface of the case body and a sealing member between the case body and the fastening member on the surface of the case body. The sealing member includes a vent portion.

Inventors

  • KIM, SOYUN

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260506
Application Date
20251029

Claims (15)

  1. A secondary battery (100) comprising: an electrode assembly (110) comprising a positive electrode, a separator, and a negative electrode; a case body (120) accommodating the electrode assembly (110) and having an open surface; a cover (130) coupled to the case body (120), the cover (130) covering the open surface of the case body (120); and a positive electrode terminal (122) connected to the positive electrode and coupled to a surface of the case body (120), wherein the positive electrode terminal (122) comprises: a fastening member (310, 410) extending into a through hole (360) in the surface of the case body (120); and a sealing member (320, 420) between the case body (120) and the fastening member (310, 410) on the surface of the case body (120), wherein the sealing member (320, 420) comprises a vent portion configured to melt at a predetermined temperature and thereby allow to vent gas inside the secondary battery (100) to the outside.
  2. The secondary battery (100) as claimed in claim 1, wherein a melting point of the vent portion is in a range of 120 °C to 125 °C.
  3. The secondary battery (100) as claimed in claim 1 or 2, wherein the fastening member (310, 410) comprises: a head portion (312, 412) on an outer side of the case body (120); and an extending portion (314, 414) extending from the head portion (312, 412) to an inside of the case body (120) through the through hole (360).
  4. The secondary battery (100) as claimed in claim 3, wherein the sealing member (320, 420) is between the case body (120) and the head portion (312, 412).
  5. The secondary battery (100) as claimed in claim 4, wherein the vent portion comprises: a first vent portion (322, 422) between a lower side of the head portion (312, 412) and the case body (120); and a second vent portion (324, 424) between an outer side of the extending portion (314, 414) and the case body (120).
  6. The secondary battery (100) as claimed in claim 5, wherein the sealing member (420) further comprises a border portion (426) at an edge of the first vent portion (422), and wherein a melting point of the border portion (426) is higher than a melting point of the first vent portion (422) and second vent portion (424).
  7. The secondary battery (100) as claimed in claim 6, wherein an upper surface of the border portion (426) is higher than an upper surface of the first vent portion (422), and wherein an upper surface of the head portion (412) is higher than the upper surface of the border portion (426).
  8. The secondary battery (100) as claimed in claim 5, wherein a width (w2) of the first vent portion (422) is larger than a width (w1) of the head portion (412).
  9. The secondary battery (100) as claimed in claim 5, wherein a corner curvature (R1) of the first vent portion (422) is less than a corner curvature (R2) of the head portion (412).
  10. The secondary battery (100) as claimed in any one of the preceding claims, wherein the sealing member (320, 420) comprises or consists of a thermoplastic resin.
  11. The secondary battery (100) as claimed in claim 3, wherein: the positive electrode terminal (122) further includes a terminal plate (330) connected to the positive electrode and arranged in the case body (120), and the extending portion (314) penetrates the terminal plate (330) and is coupled to the terminal plate (330).
  12. The secondary battery (100) as claimed in claim 11, wherein: the positive electrode terminal (122) further comprises an insulating member (340) between the terminal plate (330) and the case body (120), and the extending portion (314) penetrates the insulating member (340) and is coupled to the insulating member (340).
  13. The secondary battery (100) as claimed in claim 12, wherein a material of at least a portion of the insulating member (340) is same as a material of the vent portion.
  14. The secondary battery (100) as claimed in claim 11, wherein the vent portion comprises: a first vent portion (922) between a lower side of the head portion (912) and the case body (120); and a second vent portion (924) between an outer side of the extending portion (914) and the case body (120), and wherein at least a portion of the second vent portion (924) is between the outer side of the extending portion (914) and the terminal plate (930).
  15. A method of manufacturing a secondary battery (100), comprising: inserting an electrode assembly (110) comprising a positive electrode, a separator, and a negative electrode into a case body (120) through an open surface of the case body (120); connecting a positive electrode terminal (122) to the positive electrode and coupling the positive electrode terminal (122) to a surface of the case body (120); and coupling a cover (130) to the case body (120), the cover (130) covering the open surface of the case body (120), wherein the positive electrode terminal (122) comprises: a fastening member (310, 410) extending into a through hole (360) in the surface of the case body (120); and a sealing member (320, 420) between the case body (120) and the fastening member (310, 410) on the surface of the case body (120), and wherein the sealing member (320, 420) comprises a vent portion.

Description

1. BACKGROUND FIELD Aspects of embodiments of the present disclosure relate to a secondary battery and a method of manufacturing the same. 2. DESCRIPTION OF THE RELATED ART Unlike primary batteries that are not designed to be (re)charged, secondary (or rechargeable) batteries are batteries that are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable, small electronic devices, such as smart phones, feature phones, notebook computers, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles and electric vehicles and for storing power (e.g., home and/or utility scale power storage). A secondary battery generally includes an electrode assembly composed of a positive electrode and a negative electrode, a case accommodating the same, and electrode terminals connected to the electrode assembly. While charging and/or discharging of a secondary battery is being performed, gas may be generated inside the secondary battery. This internal gas may cause the deformation of an electrode assembly, etc., which may result in a short circuit inside the electrode assembly. As a result, the secondary battery may catch fire. In this manner, the safety of the secondary battery is deteriorated. The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure, and therefore, it may contain information that does not constitute related (or prior) art. SUMMARY Embodiments of the present disclosure provide a secondary battery and a method of manufacturing the same. These and other aspects and features of the present disclosure will be described in or will be apparent from the following description of embodiments of the present disclosure. The invention is defined by the appended claims. The description that follows is subjected to this limitation. Any disclosure lying outside the scope of said claims is only intended for illustrative as well as comparative purposes. A secondary battery according to one embodiment of the present disclosure includes an electrode assembly including a positive electrode, a separator, and a negative electrode; a case body accommodating the electrode assembly and having an open surface; a cover coupled to the case body and covering the open surface; and a positive electrode terminal connected to the positive electrode and coupled to a surface of the case body. The positive electrode terminal includes a fastening member extending into a through hole on the surface of the case body and a sealing member between the case body and the fastening member on the surface of the case body. The sealing member includes a vent portion configured to melt at a predetermined temperature and thereby allow to vent gas inside the secondary battery to the outside. According to one embodiment of the present disclosure the melting point of the vent portion may be in a range of 120 °C to 125 °C. According to one embodiment of the present disclosure, the fastening member may include a head portion on the outer side of the case body and an extending portion extending from the head portion to the inside of the case body through the through hole. According to one embodiment of the present disclosure, the sealing member may be between the case body and the head portion. According to one embodiment of the present disclosure, the vent portion may include a first vent portion between the lower side of the head portion and the case body and a second vent portion between the outer side of the extending portion and the case body. According to one embodiment of the present disclosure, the sealing member may further include a border portion at the edge of the first vent portion, and the melting point of the border portion may be higher than the melting point of the first vent portion. According to one embodiment of the present disclosure, the upper surface of the border portion may be higher than the upper surface of the first vent portion, and the upper surface of the head portion may be higher than the upper surface of the border portion. According to one embodiment of the present disclosure, a width of the first vent portion may be larger than a width of the head portion. According to one embodiment of the present disclosure, a corner curvature of the first vent portion may be less than a corner curvature of the head portion. According to one embodiment of the present disclosure, the case body may contain an alloy material. According to one embodiment of the present disclosure, the sealing member may contain an insulating material. According to one embodiment of the present disclosure, the sealing member may contain a thermoplastic resin. According to one embodiment of the present disclosure, the positive electrode terminal may further include a terminal plate connected to the positive electrode and in the case body, and the extending porti