Sealed secondary battery

Patent metadata

Field	Value
Publication number	US-10128485-B2
Application number	US-201214398223-A
Country	US
Kind code	B2
Filing date	May 2, 2012
Priority date	May 2, 2012
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

There is provided a sealed secondary battery whose current-blocking system yields little change in the actuation pressure even on long-term use. The sealed secondary battery comprises a current-blocking system 80 that is actuated by a pressure rise inside a battery case 12 to disconnect conduction path between an electrode and an electrode terminal. Current-blocking system 80 comprises a pressure-sensitive member having a pressure-sensitive deformable portion 32 that deforms from a first state via snap-through deformation to a second state upon a pressure rise inside battery case 12 , and is configured to disconnect the conduction path by snap-through deformation of pressure-sensitive deformable portion 30.

First claim

The invention claimed is:

1. A sealed secondary battery comprising
a positive electrode,
a negative electrode,
a battery case housing the positive electrode and the negative electrode,
an electrode terminal electrically connected to either the positive electrode or negative electrode and exposed outside the battery case, and
a current-blocking system that is actuated by a pressure rise inside the battery case to disconnect conduction path between the electrode and the electrode terminal, wherein
the current-blocking system comprises a pressure-sensitive member having a pressure-sensitive deformable portion in a plate form, which deforms from a first state via snap-through deformation to a second state upon a pressure rise inside the battery case, the pressure-sensitive member being configured to return from the second state to the first state,
the pressure-sensitive member comprises a flange projecting outwards from the periphery of the pressure-sensitive deformable portion, and when in the first state, the pressure-sensitive deformable portion forms a concavity curving inward toward inside of the battery from the flange,
the pressure-sensitive deformable portion has a circular periphery,
the flange has a circular outer rim,
the flange has an outer diameter a, the pressure-sensitive member has a thickness b in the pressure-sensitive deformable portion, the concavity has a depth c, and the pressure-sensitive deformable portion has an outer diameter d, satisfying the next relationships:
(1) b/a is 1.0% to 2.5%,
(2) c/a is 3.0% to 7.0%, and
(3) d/a is 50% to 90%,
the depth c of the concavity is at least 1.2 mm,
the battery is configured to disconnect the conduction path by separation of bonding or breaking off in the conduction path associated with snap-through deformation of the pressure-sensitive deformable portion,
the current-blocking system comprises a first conductive member and a second conductive member,
the conduction path is constituted to include the first conductive member and the second conductive member,
when the pressure-sensitive deformable portion is in the first state, the first conductive member is in direct connection to the second conductive member,
with the current-blocking system being configured to disconnect the conduction between the first conductive member and second conductive member by snap-through deformation of the pressure-sensitive deformable portion,
the pressure-sensitive deformable portion is provided to the first conductive member,
the pressure-sensitive deformable portion in the first state is joined to the second conductive member by welding, and
in the second conductive member, an annular groove that prescribes a location at which the second conductive member breaks off upon snap-through deformation of the pressure-sensitive deformable portion is present around a location to which the pressure-sensitive deformable portion is joined.

2. The sealed secondary battery according to claim 1 , wherein
the pressure-sensitive deformable portion comprises a tapered portion narrowing from the periphery of the pressure-sensitive deformable portion toward the center thereof, and
the flange and the tapered portion form an angle θ satisfying tan θ=0.04 to 5.0.

3. The sealed secondary battery according to claim 1 , wherein
the pressure-sensitive deformable portion is formed to have, in cross section, a dome shape curved inward toward inside of the battery.

4. The sealed secondary battery according to claim 3 , wherein the cross section of the dome shape is arched, a curvature radius e of the arc is 10 mm to 15 mm.

5. The sealed secondary battery according to claim 1 , wherein
the pressure-sensitive member has a thickness b larger than 0.15 mm in the pressure-sensitive deformable portion.

6. A battery for driving a vehicle, comprising the sealed secondary battery according to claim 1 .

7. The sealed secondary battery according to claim 1 , wherein the pressure-sensitive member has a thickness b of 0.3 mm or larger.

8. The sealed secondary battery according to claim 7 , wherein the dome shape of the pressure-sensitive deformable portion is the shape of a section cut out of a spherical shell.

9. The sealed secondary battery according to claim 1 , wherein the pressure-sensitive member has a thickness b of 0.4 mm or larger.

10. The sealed secondary battery according to claim 1 , where the current-blocking system is provided at a positive electrode side, and the pressure-sensitive member is made of aluminum or an aluminum alloy.

11. The sealed secondary battery according to claim 1 , wherein a thickness of the second conductive member at a widthwise center of the groove is 50 μm to 65 μm.

12. A sealed secondary battery comprising
a positive electrode,
a negative electrode,
a battery case housing the positive electrode and the negative electrode,
an electrode terminal electrically connected to either the positive electrode or negative electrode and exposed outside the battery case, and
a current-blocking system that is actuated by a pressure rise inside the battery case to disconnect conduction path between the electrode and the electrode terminal, wherein
the current-blocking system comprises a pressure-sensitive member having a pressure-sensitive deformable portion in a plate form, which deforms from a first state via snap-through deformation to a second state upon a pressure rise inside the battery case, the pressure-sensitive member being configured to return from the first state to the second state,
the pressure-sensitive member comprises a flange projecting outwards from the periphery of the pressure-sensitive deformable portion, and when in the first state, the pressure-sensitive deformable portion forms a concavity curving inward toward inside of the battery from the flange,
the pressure-sensitive deformable portion has a circular periphery,
the pressure-sensitive deformable portion is formed to have, in cross section, a dome shape curved inward toward inside of the battery,
the battery is configured to disconnect the conduction path by separation of bonding or breaking off in the conduction path associated with snap-through deformation of the pressure-sensitive deformable portion,
the current-blocking system comprises a first conductive member and a second conductive member,
the conduction path is constituted to include the first conductive member and the second conductive member,
when the pressure-sensitive deformable portion is in the first state, the first conductive member is in direct connection to the second conductive member,
with the current-blocking system being configured to disconnect the conduction between the first conductive member and second conductive member by snap-through deformation of the pressure-sensitive deformable portion,
the pressure-sensitive deformable portion is provided to the first conductive member,
the pressure-sensitive deformable portion in the first state is joined to the second conductive member by welding, and
in the second conductive member, an annular groove that prescribes a location at which the second conductive member breaks off upon snap-through deformation of the pressure-sensitive deformable portion is present around a location to which the pressure-sensitive deformable portion is joined.

13. The sealed secondary battery according to claim 12 , wherein the pressure-sensitive member has a thickness b of 0.3 mm or larger.

14. The sealed secondary battery according to claim 12 , wherein the pressure-sensitive member has a thickness b of 0.4 mm or larger.

15. The sealed secondary battery accord

Assignees

• Kobayashi Keiichiro
• Fukushi Takanori
• Toyota Motor Co Ltd

Inventors

• Kobayashi Keiichiro
• Fukushi Takanori

Classifications

• H01M10/34 Primary

  Gastight accumulators · CPC title

• H01M2/345 Primary

  Electricity · mapped topic

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2200/20

  Pressure-sensitive devices · CPC title

• H01M2/22

  Electricity · mapped topic