321.

Continue to refer to FIG. 4 to FIG. 10. The battery cell 30 in this embodiment of this application further includes an end cover assembly 40 hermetically connected to the housing 31. The end cover assembly 40 includes an end cover 41, an electrode terminal 45, a sealing member 42, and a barrier member 43. The electrode terminal 45 may be electrically connected to the tab 322 of the electrode assembly 32, and the electrode terminal 45 is disposed on the end cover 41. The electrode terminal 45 may be round or rectangular, which is not limited herein.

The end cover 41 is provided with a through hole 411, the sealing member 42 is configured to seal the through hole 411, and the sealing member 42 is connected to the end cover 41 to form a joint 46. The barrier member 43 is provided in the through hole 411 and a channel 44 is formed between at least part of the barrier member 43 and a side wall of the through hole 411. The channel 44 is configured to guide fluid in the battery cell 30 to the joint 46.

The end cover assembly 40 provided in this embodiment of this application, when applied to the battery cell 30, may close the opening of the housing 31, specifically, by connecting the end cover 41 to the housing 31 hermetically. The through hole 411 in the end cover 41 can be used for injecting electrolyte, discharging gas from inside the battery cell 30, or the like. The sealing member 42 is used to seal the through hole 411 and can form a joint 46 with the end cover 41. The barrier member 43 is located in the through hole 411 and can form a channel 44 with the side wall of the through hole 411, and the channel 44 communicates with the internal space of the housing 31. The barrier member 43 can partially stop the fluid inside the battery cell 30. With the provision of the channel 44, when a leak occurs at the joint 46 between the sealing member 42 and the end cover 41, the fluid inside the battery cell 30 can flow through the channel 44 to the joint 46 and be detected so as to provide feedback on whether a leak has occurred between the sealing member 42 and the end cover 41. The sealing performance of the end cover assembly 40 can be better ensured to meet the sealing requirement of the battery cell 30.

For example, a given amount of helium gas can be injected inside the battery cell 30, and when a leak occurs at the joint 46 between the sealing member 42 and the end cover 41 due to poor welding or other reasons, the helium gas will flow to the joint 46 through the channel 44 formed between the barrier member 43 and the side wall of the through hole 411. Therefore, a leaking location of the joint 46 can be detected by a detection equipment, and repair welding or other remedial measures can be taken to ensure the proper sealing of the joint 46 between the sealing member 42 and the end cover 41, thus guaranteeing safety and service life of the battery cell 30.

In the end cover assembly 40 provided in this embodiment of this application, the channel 44 is formed between the barrier member 43 and the side wall of the through hole 411, so that the channel 44 is easy to process and form, the strength loss of the barrier member 43 is small, and the barrier member 43 is not easily deformed. This effectively avoids blocking of the channel 44 blocking due to the deformation of the barrier member 43, thereby ensuring testing accuracy of the sealing performance of the joint 46 between the sealing member 42 and the end cover 41.

Referring to FIG. 11, in some embodiments, a cross-sectional area of the channel 44 progressively decreases along an axial direction X of the through hole 411 toward a side of the sealing member 42 closer to the through hole 411. With the foregoing configuration, a lower opening of the channel 44 can be enlarged as much as possible to help the fluid flow to the joint 46, and ensure stable cooperation between the barrier member 43 and the through hole 411.

Continue to refer to FIG. 11. For example, the cross-sectional area of the channel 44 may gradually decrease along the axial direction X of the through hole 411 toward the side of the sealing member 42 closer to the through hole 411.

Referring to FIG. 12, in some embodiments, the cross-sectional area of the channel 44 may alternatively decrease segment by segment along the axial direction X of the through hole 411 toward the side of the sealing member 42 closer to the through hole 411, which can also achieve progressive decrease of the cross-sectional area of the channel 44.

Still referring to FIG. 4 to FIG. 12, in some embodiments, in the end cover assembly 40 provided in the foregoing embodiments, the end cover 41 may be further provided with a depression 412, and the depression 412 is disposed in correspondence to the through hole 411 and communicates with the through hole 411. In some embodiments, the depression 412 can be disposed in correspondence to the through hole 411 in the axial direction X of the through hole 411, and the depression 412 is configured to accommodate the sealing member 42. The provision of the depression 412 facilitates easy installation of the sealing member 42 and connection of it to the end cover 41 to form the joint 46, helping the sealing of the through hole 411, In addition, this allows the sealing member 42 to be disposed without protruding from the end cover 41, thereby reducing an overall thickness of the end cover assembly 40.

In some embodiments, the sealing member 42 may be provided with an escape groove 421 on a side close to the barrier member 43. The provision of the escape groove 421 prevents the sealing member 42 from interfering with the barrier member 43 during fitting, helping the fitting of the sealing member 42.

Referring to FIG. 13 to FIG. 14, in some embodiments, in the end cover assembly 40 provided in the foregoing embodiments, the barrier member 43 may be provided with a first notch 433 in a surface facing the side wall of the through hole 411, and the channel 44 is formed between the first notch 433 and the side wall. With the first notch 433 provided at the barrier member 43, the barrier member 43 cannot be fully attached to the side wall of the through hole 411, helping the formation of the channel 44.

It can be understood that forming the first notch 433 in the side wall of the barrier member 43 so that the channel 44 is formed between the first notch 433 and the side wall of the through hole 411 is only one implementation, which is not limitation. In some embodiments, the first notch