JP2010262792A - Secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery capable of improving cycle life by radiating heat generated in the center inside a laminated body excellently to the outside to suppress thermal runaway. <P>SOLUTION: The secondary battery is equipped with a container 11 having a positive electrode terminal 15 and a negative electrode terminal 16 and a laminated body 12 which is installed inside the container 11 and in which a positive electrode plate 18 connected to the positive electrode terminal 15 and a negative electrode plate 20 connected to the negative electrode terminal 16 are alternately superimposed through a separator 21. An electrolyte solution is stored in the container 11 and high-temperature conductivity gas is filled. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a secondary battery.

  In recent years, secondary batteries that can be repeatedly charged and discharged have been widely used in various fields. For example, a small type is used as a power source for an electronic device such as a mobile phone or a video camera, and a large type is used as a power source for an electric vehicle or a household power storage device. As such a secondary battery, a non-aqueous electrolyte secondary battery such as a stacked lithium ion secondary battery has been developed (see, for example, Patent Documents 1 and 2).

In such a secondary battery, at least one of the positive electrode plate and the negative electrode plate is packaged with a separator, and the positive electrode plate and the negative electrode plate are alternately laminated to form a laminate. And the heat | fever which generate | occur | produces in a positive electrode plate, a negative electrode plate, etc. in the case of charging / discharging etc. is radiated from the container outer wall and terminal part which accommodate a positive electrode plate and a negative electrode plate.
The heat transfer path at the time of this heat dissipation is through a path through the contact portion between the container and the laminate, a path through the electrolytic solution, and a gas (dry air or nitrogen) filled between the container and the laminate. There is a route.

JP 2003-45498 A JP 2007-273348 A

  However, in the case of the above-described conventional secondary battery, there is a problem in that the heat generated at the center of the laminated body cannot be sufficiently dissipated to the outside, and the temperature of the laminated body rises to reduce the cycle life.

  The present invention has been made in view of the above circumstances, and provides a secondary battery capable of improving the cycle life by suppressing the heat runaway by favorably dissipating the heat generated at the center of the laminate to the outside. With the goal.

The present invention employs the following means in order to solve the above problems.
The secondary battery according to the present invention includes a container having a positive electrode terminal and a negative electrode terminal, and a positive electrode plate provided in the container and connected to the positive electrode terminal and a negative electrode plate connected to the negative electrode terminal. The container is characterized in that an electrolyte solution is stored and a high thermal conductivity gas is filled in the container.

According to this configuration, since the container is filled with the high thermal conductivity gas, the heat generated in the laminated body is efficiently transferred to the container via the high thermal conductivity gas.
That is, the heat flux from the laminate to the high thermal conductivity gas is increased, and the heat flux from the high thermal conductivity gas to the container is increased. In other words, the amount of heat transferred from the laminate to the high thermal conductivity gas is increased, and the amount of heat transferred from the high thermal conductivity gas to the container is increased. Then, heat is radiated from the outer wall of the container to the outside.
On the other hand, in the laminated body, the temperature at the surface of the laminated body is lowered due to heat transfer from the surface of the laminated body to the high thermal conductivity gas. Move to the side. And the heat which moved to this laminated body surface side moves from the surface of a laminated body to high thermal conductivity gas, and is finally thermally radiated outside via a container.
Therefore, the heat generated at the center of the laminate can be suitably radiated to the outside.

The secondary battery according to the present invention is characterized in that the high thermal conductivity gas is filled at a pressure higher than atmospheric pressure.
According to this configuration, since the high thermal conductivity gas is filled at a pressure equal to or higher than the atmospheric pressure, compared with the case where the high thermal conductivity gas is filled at the same pressure as the atmospheric pressure, the laminate is changed to the high thermal conductivity gas. The amount of heat transfer can be increased.

In the secondary battery according to the present invention, the container has a gas supply hole into which the high thermal conductivity gas can be injected, and a check valve is provided in the gas supply hole.
According to this configuration, since the check valve is provided in the gas supply hole, the high thermal conductivity gas can be easily filled.

The high thermal conductivity gas is helium gas or hydrogen gas.
According to this configuration, since the high thermal conductivity gas is helium gas or hydrogen gas, the thermal conductivity is relatively high.

  ADVANTAGE OF THE INVENTION According to this invention, the heat | fever generate | occur | produced in the laminated body internal center can also be thermally radiated outside, a thermal runaway can be suppressed, and the secondary battery which can improve cycle life can be provided.

1 is a partially broken perspective view showing a secondary battery according to an embodiment of the present invention. It is the schematic of the II-II sectional view taken on the line of FIG.

An embodiment according to the present invention will be described with reference to FIGS. 1 and 2.
The secondary battery 10 according to this embodiment includes a container 11 that stores an electrolytic solution S (see FIG. 2) made of an organic solvent, and a laminated body 12 that is disposed in the container 11.

As shown in FIG. 1, the container 11 is formed in a box shape made of aluminum.
The container 11 is provided with a positive electrode terminal 15, a negative electrode terminal 16, and an aluminum safety valve 17 on an upper portion 11 a thereof. A gas supply hole 11c is formed below the one side wall portion 11b of the container 11, and a check valve 30 is attached to the gas supply hole 11c.

The safety valve 17 is activated during the thermal runaway of the secondary battery 10 to ensure the safety of the secondary battery 10. The safety valve 17 ensures the safety of the secondary battery 10 by releasing the gas inside the container 11 to the outside even if the temperature and pressure inside the container 11 are extremely increased.
The safety valve 17 is opened when the upper part 11a of the container 11 is dug and the internal pressure of the container 11 becomes equal to or higher than a predetermined pressure.

  The check valve 30 is configured to allow fluid to flow from the outside to the inside (forward direction) of the container 11 and to automatically close when attempting to flow in the reverse direction.

  The laminate 12 includes a plurality of positive plates 18 and negative plates 20 that are alternately laminated so that the lower part is immersed in the electrolyte S, and a plurality of separators 21 that are disposed between the positive plates 18 and the negative plates 20. It has. In FIGS. 1 and 2, the positive electrode plate 18, the negative electrode plate 20, and the separator 21 are displayed as having a sufficient thickness so that the drawings can be easily seen. , Each close.

  Tabs 18 </ b> A and 20 </ b> A are arranged on the edge portion on the upper part 11 a side of the sheet edge portions of the positive electrode plate 18 and the negative electrode plate 20, respectively. Here, in the positive electrode plate 18 and the negative electrode plate 20, the tabs 18 </ b> A and 20 </ b> A are arranged so as to be biased to either side from the edge center. And the positive electrode plate 18 and the negative electrode plate 20 are laminated | stacked so that mutual tab 18A, 20A may not be biased | biased from the edge center to a different side. With such a configuration, the tab 18 </ b> A of the positive electrode plate 18 is connected to the positive electrode terminal 15, and the tab 20 </ b> A of the negative electrode plate 20 is connected to the negative electrode terminal 16.

  The separator 21 is for insulating the positive electrode plate 18 and the negative electrode plate 20 adjacent to each other, and is made of a sheet-like resin such as polypropylene, for example. In addition, at least one of the positive electrode plate 18 and the negative electrode plate 20 is sealed to the separator 21 with the tab 18A or the tab 20A protruding, so that the adjacent positive electrode plate 18 and negative electrode plate 20 are insulated. May be.

  As shown in FIG. 2, the lower portion of the laminated body 12 having such a configuration is immersed in the electrolytic solution S. And electrolyte solution S has spread | diffused between each contact surface of the positive electrode plate 18, the negative electrode plate 20, and the separator 21 (capillary phenomenon).

The container 11 is filled with helium gas (high thermal conductivity gas) G together with the electrolyte S.
The helium gas G is filled at a pressure higher than atmospheric pressure. In addition, said safety valve 17 is designed supposing the case where temperature and pressure rise extremely on the basis of the pressure of helium gas G.
The helium gas G is first filled with the electrolyte solution S from the gas supply hole 11c through the check valve 30 after the container 11 is evacuated. It is also possible to fill the electrolytic solution S and the helium gas G in separate steps.

Next, the heat radiation effect of the secondary battery 10 having the above configuration will be described.
First, when the secondary battery 10 is charged and discharged, heat is generated in each positive electrode plate 18 and each negative electrode plate 20, and the laminate 12 is heated. The heat of the laminated body 12 is transferred to the container 11 through the contact portion between the laminated body 12 and the container 11, the electrolytic solution S, or the helium gas G, and is radiated mainly from the outer wall of the container 11 to the outside. .

  The helium gas G has a high thermal conductivity, and the heat fluxes of the stacked body 12 and the container 11 are relatively large. In other words, the amount of heat transfer from the surface of the laminate 12 to the helium gas G increases, and the amount of heat transfer from the helium gas G to the container 11 increases. The heat of the container 11 is radiated to the outside.

  When heat flows from the surface of the stacked body 12 to the helium gas G, the temperature on the surface side of the stacked body 12 decreases. The temperature on the central side (inward side) of the laminated body 12 becomes higher than the surface side of the laminated body 12, and the heat on the central side moves to the front side in the laminated body 12. The heat moved to the surface side flows into the helium gas G and is radiated to the outside through the container 11.

As described above, according to the present embodiment, the heat flux from the stacked body 12 to the helium gas G is increased, and the heat flux from the helium gas G to the container 11 is increased. In other words, the heat transfer amount from the stacked body 12 to the helium gas G is increased, and the heat transfer amount from the helium gas G to the container 11 is increased. In short, the heat of the surface of the laminate 12 is transferred favorably to the container 11. Then, heat is radiated from the outer wall of the container 11 to the outside.
On the other hand, in the laminated body 12, the temperature on the surface side of the laminated body 12 is lowered by the transfer of heat from the surface of the laminated body 12 to the helium gas G. Moves to the surface of the laminate 12. The heat that has moved to the surface of the laminate 12 moves from the surface of the laminate 12 to the high thermal conductivity gas, and is finally radiated to the outside through the container 11.
Therefore, the heat generated at the center inside the laminate can be suitably radiated to the outside.

When nitrogen or dry air having a relatively low thermal conductivity is filled in place of the helium gas G, the amount of heat transferred from the laminate 12 to the container 11 through the gas becomes small. For this reason, the heat of the center side of the laminated body 12 tends to swell inside, and the laminated body 12 may be overheated.
On the other hand, in this embodiment, the heat generated at the center of the laminate 12 can be radiated well to the outside to suppress thermal runaway, and the cycle life can be improved.

  Further, since the helium gas G is filled at a pressure equal to or higher than the atmospheric pressure, the heat transfer amount from the stacked body 12 to the helium gas G is increased as compared with the case where the helium gas G is filled at the same pressure as the atmospheric pressure. be able to. Thereby, the heat generated at the center of the laminate 12 can be radiated to the outside satisfactorily.

  Further, since the check valve 30 is provided in the gas supply hole 11c, the helium gas G can be easily filled.

  Further, according to the helium gas G, since the thermal conductivity is relatively high among various gases, the heat of the stacked body 12 can be dissipated to the outside in outline. Moreover, since it is inactive, the electrolyte solution S and the laminated body 12 are not altered in the container 11.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the shape of the container 11 is not limited to the box shape, and other shapes can be adopted, and the material is naturally not limited to aluminum.

  In the above-described embodiment, the helium gas G is used as the high thermal conductivity gas, but hydrogen gas may be used. As this high thermal conductivity gas, those having higher thermal conductivity than dry air and nitrogen gas can be used, but an inert gas is better.

DESCRIPTION OF SYMBOLS 10 ... Secondary battery 11 ... Container 11c ... Gas supply hole 12 ... Laminated body 15 ... Positive electrode terminal 16 ... Negative electrode terminal 18 ... Positive electrode plate 20 ... Negative electrode plate 21 ... Separator 30 ... Check valve G ... Helium gas (high thermal conductivity gas) )
S ... Electrolyte

Claims (4)

A container having a positive terminal and a negative terminal;
Provided inside this container, comprising a laminate in which a positive electrode plate connected to the positive electrode terminal and a negative electrode plate connected to the negative electrode terminal are alternately stacked via a separator,
The secondary battery is characterized in that an electrolytic solution is stored in the container and is filled with a high thermal conductivity gas.   The secondary battery is characterized in that the high thermal conductivity gas is filled at a pressure higher than atmospheric pressure.   The secondary battery according to claim 1, wherein the container has a gas supply hole into which the high thermal conductivity gas can be injected, and a check valve is provided in the gas supply hole.   The secondary battery according to claim 1, wherein the high thermal conductivity gas is helium gas or hydrogen gas.

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