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EP-4113720-B1 - BATTERY MODULE AND BATTERY PACK

EP4113720B1EP 4113720 B1EP4113720 B1EP 4113720B1EP-4113720-B1

Inventors

  • RHEE, SEO ROH
  • KANG, JI EUN
  • PARK, DA SOM
  • HAN, JEONG WOO

Dates

Publication Date
20260513
Application Date
20220628

Claims (13)

  1. A battery module (100) comprising: a case (110); a plurality of battery cells (120) accommodated in the case (110); a first busbar (131) aimed at connecting at least one of the plurality of battery cells (120) to a conductive connector (200); and a second busbar (132) connecting a first battery cell group (120a) including at least a first battery cell among the plurality of battery cells (120) to a second battery cell group (120b) including a second battery cell among the plurality of battery cells (120), wherein the first busbar (131) includes a first connection portion (131a) connected to the at least one battery cell, a second connection portion (131b) connected to the conductive connector (200), and a first linking portion (131c) connecting the first connection portion (131a) and the second connection portion (131b) to each other, wherein the first linking portion (131c) includes a material having a melting point lower than that of the first connection portion(131a) or the second connection portion (131b), characterized in that the second busbar (132) includes a third connection portion (132a) connected to a positive electrode of the first battery cell group (120a), a fourth connection portion (132b) connected to a negative electrode of the second battery cell group (120b), and a second linking portion (132c) connecting the third connection portion (132a) and the fourth connection portion (132b) to each other, and the second linking portion (132c) includes a material having a melting point lower than that of the third connection portion (132a) or the fourth connection portion (132b).
  2. The battery module (100) of claim 1, wherein the first connection portion (131a) is disposed inside the case (110), the second connection portion (131b) is exposed to the outside of the case (110), and wherein the conductive connector (200) disposed outside the case (100).
  3. The battery module (100) of claim 1, wherein the first connection portion (131a) or the second connection portion (131b) includes copper, and the first linking portion (131c) includes aluminum.
  4. The battery module (100) of claim 1, wherein the first linking portion (131c) includes a first portion (131c-1) forming a boundary with the first connection portion (131a), a second portion (131c-2) forming a boundary with the second connection portion (131b), and a third portion (131c-3) connecting the first portion (131c-1) and the second portion (131c-2) to each other, wherein the first portion (131c-1) and the second portion (131c-2) include a material having a melting point lower than that of the first connection portion (131a) or the second connection portion (131b), and the third portion (131c-3) includes the same material as that of the first connection portion (131a) or the second connection portion (131b).
  5. The battery module (100) of claim 1, wherein the at least one battery cell (120) includes a pouch type casing and an electrode assembly (123) accommodated in the casing, a sealing portion (122) formed on the edge of the casing includes a weak portion (122a) having a sealing strength weaker than that of other portions, and the first linking portion (131c) is disposed to face the weak portion (122a).
  6. The battery module (100) of claim 1, wherein the first linking portion (131c) is coupled to the first connection portion (131a) or the second connection portion (131b) by welding.
  7. The battery module (100) of claim 1, wherein the second linking portion (132c) includes aluminum, and the third connection portion (132a) or the fourth connection portion (132b) includes copper.
  8. A battery pack (1000) comprising: a pack case (300); battery modules (100) disposed inside the pack case (300); and an intermodule busbar (200) electrically connecting the battery modules (100) to each other, wherein at least one of the battery modules (100) includes: a plurality of battery cells (120); a first busbar (131) in the at least one of the battery modules (100) electrically connecting at least one of the plurality of battery cells (120) to the intermodule busbar (200); and a second busbar (132) connecting a first battery cell group (120a) including at least a first battery cell among the plurality of battery cells (120) to a second battery cell group (120b) including a second battery cell among the plurality of battery cells (120), wherein the first busbar (131) includes a first connection portion (131a) connected to the at least one battery cell, a second connection portion (131b) connected to the intermodule busbar (200), and a first linking portion (131c) connecting the first connection portion (131a) and the second connection portion (131b) to each other, wherein the first connection portion (131a) or the second connection portion (131b) includes a first material, and the first linking portion (131c) includes a second material having a melting point lower than that of the first material, characterized in that the second busbar (132) includes a third connection portion (132a) connected to a positive electrode of the first battery cell group, a fourth connection portion (132b) connected to a negative electrode of the second battery cell group, and a second linking portion (132c) connecting the third connection portion (132a) and the fourth connection portion (132b) to each other, and the second linking portion (132c) includes a material having a melting point lower than that of the third connection portion (132a) or the fourth connection portion (132b).
  9. The battery pack (1000) of claim 8, wherein the intermodule busbar (200) includes the first material in a portion in contact with at least the second connection portion (131b).
  10. The battery pack (1000) of claim 8, wherein the first linking portion (131c) is coupled to the first connection portion (131a) or the second connection portion (131b) by welding.
  11. The battery pack of (1000) claim 8, wherein the first linking portion (131c) includes a first portion (131c-1) forming a boundary with the first connection portion (131a), a second portion (131c-2) forming a boundary with the second connection portion (131b), and a third portion (131c-3) connecting the first portion (131c-1) and the second portion (131c-2) to each other, and the first portion (131c-1) includes a material having a melting point lower than that of the first connection portion (131a).
  12. The battery pack (1000) of claim 8, wherein the first linking portion (131c) includes a first portion (131c-1) forming a boundary with the first connection portion (131a), a second portion (131c-2) forming a boundary with the second connection portion (131b), and a third portion (131c-3) connecting the first portion (131c-1) and the second portion (131c-2) to each other, and the second portion (131c-2) includes a material having a melting point lower than that of the second connection portion (131b).
  13. The battery pack (1000) of claim 8, wherein the first linking portion (131c) includes a first portion (131c-1) forming a boundary with the first connection portion (131a), a second portion (131c-2) forming a boundary with the second connection portion (131b), and a third portion (131c-3) connecting the first portion (131c-1) and the second portion (131c-2) to each other, wherein the first portion (131c-1) includes a material having a melting point lower than that of the first connection portion (131a), the second portion (131c-2) includes a material having a melting point lower than that of the second connection portion (131b), and the third portion (131c-3) includes a material having the same melting point as that of the first connection portion (131a) or the second connection portion (131b).

Description

BACKGROUND 1. FIELD The present disclosure relates to a battery module and a battery pack. 2. DESCRIPTION OF RELATED ART Recently, battery packs that may be charged and discharged have been widely used as an energy source for wireless mobile devices and have come to prominence as a power source of electric vehicles (EVs), hybrid electric vehicles (HEVs), and electric bicycles (eBikes), as these vehicles are considered to be a solution to air pollution from existing gasoline and diesel vehicles that use fossil fuels. In addition, a lithium secondary battery is mainly used as a power source for an electric vehicle or a hybrid vehicle. Since a large amount of power for an operation such as motor driving is required, high-capacity battery modules configured by connecting battery modules, in which a plurality of high-power battery cells are electrically connected, in series or parallel, have generally been used. Compared to small mobile devices in which one, two or three battery cells per device are used, medium to large devices, such as electric vehicles and electric bicycles, require higher power and higher capacity. For these vehicles, a plurality of high-power battery cells are primarily electrically connected to each other to configure a battery module which will meet the required specification for a high-power, high-capacity battery pack. Meanwhile, when a decomposition reaction continues in abnormal operating conditions (such as overcharging, overdischarging, high temperature exposure, an electrical short circuit, etc.), heat and gas may occur inside such a secondary battery, and acceleration of the decomposition reaction under high temperature and high pressure conditions may cause a fire or explosion. In particular, this problem may cause a serious large-scale accident in the case where a high-power, high-capacity battery pack having a plurality of battery cells is used. When thermal runaway occurs in a specific battery module, a thermally conductive material may be discharged to the outside of the module, which may break an insulation state between the battery module and a neighboring battery module. In this case, a very high current may instantaneously flow between the battery modules, causing thermal runaway in a neighboring battery module, which may lead to a fire in the entire battery pack. A battery pack and a battery module comprising a plurality of electrically connected battery cells accommodated in a case are described in US 2020/168887 A1, US 202/112012 A1, KR 2016 0068722 A and KR 2013 0064091 A. SUMMARY Embodiments of the present invention provide a battery module and battery pack for a secondary battery having improved safety and reliability by preventing an event, such as an explosion and thermal runaway, occurring in the battery module from propagating to other battery modules and further to the entire battery pack. Specifically, embodiments provide a cut-off unit or an electrical disconnector for cutting off an electrical connection between a specific battery module and a neighboring structure (e.g., another battery module) when an event, such as thermal runaway, occurs in the corresponding battery module. The invention is set out in the appended claims. According to one aspect of the present disclosure, a battery module includes: a case; a plurality of battery cells accommodated in the case; and a first busbar aimed at connecting at least one of the plurality of battery cells to a conductive connector, wherein the first busbar includes a first connection portion connected to the at least one battery cell, a second connection portion connected to the conductive connector, and a first linking portion connecting the first connection portion and the second connection portion to each other, wherein the first linking portion includes a material having a melting point lower than that of the first connection portion or the second connection portion. The first connection portion may be disposed inside the case, the second connection portion may be exposed to the outside of the case, and wherein the conductive connector may be disposed outside the case. The first connection portion or the second connection portion may include copper, and the first linking portion may include aluminum. The first linking portion may include a first portion forming a boundary with the first connection portion, a second portion forming a boundary with the second connection portion, and a third portion connecting the first portion and the second portion to each other, wherein the first portion and the third portion may include a material having a melting point lower than that of the first connection portion or the second connection portion, and the second portion may include the same material as that of the first connection portion or the second connection portion. The at least one battery cell may include a pouch type casing and an electrode assembly accommodated in the casing, a sealing portion formed on an edge of