Electric power storage device

Patent metadata

Field	Value
Publication number	US-10096815-B2
Application number	US-201515533417-A
Country	US
Kind code	B2
Filing date	Nov 30, 2015
Priority date	Dec 11, 2014
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A rechargeable battery is provided with a pressure release valve and a current interruption mechanism. The current interruption mechanism includes a deformation plate. When the internal pressure of the case reaches an interruption activation pressure, the deformation plate receives the internal pressure and is deformed to break a conducting portion. In the current interruption mechanism, a pressure that is set for maintaining the sealing at the contact portion between the deformation plate and a negative electrode conductor is defined as a sealing portion withstanding pressure, and the pressure that is set for maintaining the shape of the case is defined as a case withstanding pressure. The pressure for activating the pressure release valve is defined as a valve activation pressure. In this case, the sealing portion withstanding pressure and the valve activation pressure are set higher than the interruption activation pressure and lower than the case withstanding pressure.

First claim

The invention claimed is:

1. A power storage device comprising:
an electrode assembly;
a case, which accommodates the electrode assembly;
an electrode terminal, which supplies and receives power to and from the electrode assembly;
a conductor, which connects the electrode assembly to the electrode terminal;
a current interruption mechanism, which interrupts a current-carrying path between the electrode terminal and the electrode assembly when an internal pressure of the case reaches an interruption activation pressure; and
a pressure release valve, which is located on a wall portion of the case and releases the pressure in the case to the outside of the case when the internal pressure of the case exceeds a valve activation pressure, wherein
the current interruption mechanism includes
a conducting portion, which allows current to flow between the electrode terminal and the conductor, and
a deformation plate, which contacts the conductor and defines, in the case, a first space, a pressure in which is equal to the internal pressure of the case, and a second space, a pressure in which is maintained at a pressure outside the case, wherein a contact portion between the deformation plate and the conductor is sealed,

the current interruption mechanism is configured such that, when the internal pressure of the case reaches the interruption activation pressure, the deformation plate receives the internal pressure and is deformed to break the conducting portion,
the current interruption mechanism is further configured such that, when the internal pressure of the case exceeds a sealing portion withstanding pressure, which is defined as a pressure that is set for maintaining the sealing at the contact portion, a sealing function at a sealing portion is lost, thereby releasing the pressure in the case to the outside of the case from the first space via the second space,
a pressure that is set for maintaining the shape of the case is defined as a case withstanding pressure,
the sealing portion withstanding pressure and the valve activation pressure are set higher than the interruption activation pressure and lower than the case withstanding pressure, and
the sealing portion withstanding pressure is set higher than the valve activation pressure.

2. The power storage device according to claim 1 , wherein
the current interruption mechanism includes a contact plate, which allows current to flow between the electrode terminal and the conductor via the conducting portion and is located in the second space, and
the deformation plate contacts a surface of the conductor facing the electrode assembly in a state in which the deformation plate is located at a position closer to the electrode assembly than the contact plate and between the conducting portion and the electrode assembly and in which the deformation plate covers the conducting portion.

3. The power storage device according to claim 1 , wherein the power storage device is a rechargeable battery.

4. A power storage device comprising:
an electrode assembly;
a case, which accommodates the electrode assembly;
an electrode terminal, which supplies and receives power to and from the electrode assembly;
a conductor, which connects the electrode assembly to the electrode terminal;
a current interruption mechanism, which interrupts a current-carrying path between the electrode terminal and the electrode assembly when an internal pressure of the case reaches an interruption activation pressure; and
a pressure release valve, which is located on a wall portion of the case and releases the pressure in the case to the outside of the case when the internal pressure of the case exceeds a valve activation pressure, wherein
the current interruption mechanism includes
a conducting portion, which allows current to flow between the electrode terminal and the conductor, and
a deformation plate, which contacts the conductor and defines, in the case, a first space, a pressure in which is equal to the internal pressure of the case, and a second space, a pressure in which is maintained at a pressure outside the case, wherein a contact portion between the deformation plate and the conductor is sealed,

the current interruption mechanism is configured such that, when the internal pressure of the case reaches the interruption activation pressure, the deformation plate receives the internal pressure and is deformed to break the conducting portion,
the current interruption mechanism is further configured such that, when the internal pressure of the case exceeds a sealing portion withstanding pressure, which is defined as a pressure that is set for maintaining the sealing at the contact portion, a sealing function at a sealing portion is lost, thereby releasing the pressure in the case to the outside of the case from the first space via the second space,
in a case in which the electrode assembly expands and contracts in accordance with normal charging and discharging, a pressure that is set for maintaining the shape of the case within a range in which the case expands and contracts in accordance with the expansion and contraction of the electrode assembly is defined as a case withstanding pressure,
the sealing portion withstanding pressure and the valve activation pressure are set higher than the interruption activation pressure and lower than the case withstanding pressure, and
the sealing portion withstanding pressure is set higher than the valve activation pressure.

5. A power storage device comprising:
an electrode assembly;
a case, which accommodates the electrode assembly;
positive-electrode and negative electrode terminals, which supply and receive power to and from the electrode assembly;
a current reduction mechanism, which reduces current from the electrode terminals to the electrode assembly when the internal pressure of the case reaches an activation pressure; and
a pressure release valve, which is located on a wall portion of the case and releases the pressure in the case to the outside of the case when the internal pressure of the case exceeds a valve activation pressure, wherein
the current reduction mechanism includes
a short-circuit member electrically connected to one of the electrode terminals, and
a deformation plate, which is arranged to be in contact with the case and defines a first space, a pressure in which is equal to the internal pressure of the case, and a second space, a pressure in which is maintained at a pressure outside the case, wherein a contact portion between the deformation plate and the case is sealed,

the current reduction mechanism is configured such that when the internal pressure of the case reaches the activation pressure, the deformation plate is deformed by receiving the internal pressure and allows current to flow through the short-circuit member via the deformation plate,
the current interruption mechanism is further configured such that, when the internal pressure of the case exceeds a sealing portion withstanding pressure, which is defined as a pressure that is set for maintaining the sealing at the contact portion, a sealing function at a sealing portion is lost, thereby releasing the pressure in the case to the outside of the case from the first space via the second space,
a pressure that is set for maintaining the shape of the case is defined as a case withstanding pressure,
the sealing portion withstanding pressure and the valve activation pressure are set higher than the activation pressure and lower than the case withstanding pressure, and
the sealing portion withstanding pressure is set higher than the valve activation pressure.

Assignees

• Toyota Jidoshokki Kk

Inventors

• Hirose Takayuki
• Suzuki Shinji
• Okuda Motoaki

Classifications

• H01M50/176

  for prismatic or rectangular cells (H01M50/181 takes precedence) · CPC title

• H01M50/103

  prismatic or rectangular (H01M50/109, H01M50/11 take precedence) · CPC title

• H01M50/553

  Terminals adapted for prismatic, pouch or rectangular cells · CPC title

• H01M50/55

  on the same side of the cell · CPC title

• H01M2/0237

  Electricity · mapped topic