Toyota Jidosha Kabushiki Kaisha

Fuji Springs Co., Inc.

Katsumi Ito

Satoshi Suzuki

Akira Fujii

Tomohiro Matsuura

Toshihiro Odagaki

A sealed battery is provided in which a case is partially provided with a safety valve that is provided with a thin portion, which is formed thinner than the peripheral portion of the safety valve. A portion of the safety valve surrounding the thin portion is provided with a slit for preventing heat conduction from the other portions of the case to the thin portion, said slit being formed so as to surround the thin portion.

Sealed battery having a safety valve

Disclosed is a sealed secondary battery provided with a current cut-off device which employs an inexpensive and uncomplicated construction, without the need to mount a separate current cut-off device on the battery body. A sealed secondary battery () comprises a battery casing () and a sealing plate (), an electrode body () and current collecting plates () provided on the inside of this casing (). A contact section () formed as part of the bottom () of this battery casing () is bowed further inwards towards the negative electrode-side current collecting plate () than the peripheral section of the bottom () of this battery casing (). At this contact section (), the inside face of the bottom () of the battery casing contacts the current collecting plate () at the negative electrode end, but this electrical contact between the contact section () and the current collecting plate () at the negative electrode end is cut off when outward swelling of the contact section () takes place, produced by a rise in internal pressure in the casing in a sealed condition.

Sealed secondary battery

A safety valve () formed in a portion of a case of a sealed battery includes a fracture groove portion () formed in a thin portion (). The thin portion () is formed in a horizontally long shape or a vertically long shape that has a curved outer edge portion () in which at least a portion of the outer edge portion () is curved. This thin portion () has a center straight groove portion () that extends in the longer direction of the thin portion in the center portion of the thin portion, and a pair of side groove portions () that are formed in both side in the longer direction of the center straight groove portion () and connected to longer direction end portions (A,B,A,B,A,B) of the center straight groove portion. Here, a portion of the side groove portion () is formed curved following the curved outer edge portion ().

Sealed battery and vehicle

The sealed battery has a battery container () and a power generating element sealed inside the battery container. The battery container is provided with a fill opening (), an annular ridge (), which extends around the entire circumference of the outer face surrounding the fill opening, and an annular indentation () on the inside of the inner wall surface of the annular ridge, and has a sealing cap (), which fits into the annular indentation and covers the fill opening. The sealing cap is joined by being welded to the inner wall surface of the annular ridge around the entire circumference at the edge thereof. Since heat is not well transferred from the inside to the outside of the outer wall surface of the annular ridge, the effective thermal capacity during welding is mostly determined by the structure of the area inside the outer wall surface of the annular ridge. Consequently, the effective thermal capacity is nearly uniform independent of direction. Thus, it is possible to provide a sealed battery, a manufacturing method thereof, and vehicles and machinery in which the same is installed, wherein the opening can be closed under consistent welding conditions around the entire circumference.

Growing community of inventors

Seto, Japan

Katsumi Ito