JP2008270032A - Secondary-battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary-battery module that avoids secondary-battery explosion. <P>SOLUTION: The secondary-battery module has secondary batteries 1, a storage casing 7 for storing the secondary batteries 1, each explosion-proof valve 6 arranged in each secondary battery 1 and having a rupture structure, and each protrusion 8 facing each explosion-proof valve 6 and internally provided onto the storage casing 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a secondary battery module excellent in safety when the gas pressure in the secondary battery is increased.

A secondary battery such as a lithium ion battery, for example, is a gas generated in the secondary battery due to heat generation due to oxidation of the electrolyte in the secondary battery or destruction of the crystal structure when charged outside a predetermined voltage range. May cause the secondary battery volume to expand and eventually burst. Therefore, in the conventional technology, in order to prevent this rupture, a rupture disk is provided in the secondary battery as a safety device for the secondary battery, and when the gas pressure in the secondary battery reaches a predetermined pressure, the rupture disk is reversed and broken and the internal pressure is increased. Is opened to prevent the secondary battery from bursting (see, for example, Patent Document 1).
. In addition, a cutting blade inside the secondary battery and a flexible thin plate are arranged at a position facing the cutting blade, and the internal pressure is reduced by cutting the flexible thin plate that is bent by the increase in gas pressure in the secondary battery. It is opened to prevent the secondary battery from bursting (see, for example, Patent Document 2).
Japanese Utility Model Publication No. 5-62956 Japanese Utility Model Publication No. 4-14850

For example, a secondary battery used in a hybrid vehicle needs to be installed in a limited space in the vehicle, so that further downsizing is required. For this reason, since the demand for high airtightness in the secondary battery is increased and the risk of generating gas in the secondary battery is increased, it is an urgent task to improve the safety against this.

However, in the structure using the rupture disk described in Japanese Utility Model Laid-Open No. 5-62956, the rupture disk is required to be reliably reversed and broken when the gas pressure in the secondary battery reaches a predetermined pressure. If the product is not kept in high quality, there will be variations in performance, and the rupture disk may not break even if the gas pressure in the secondary battery exceeds a predetermined pressure. In addition, in the case of a structure in which a cutting blade is provided in a secondary battery described in Japanese Utility Model Publication No. 4-14850, a space for providing a cutting blade or the like in the secondary battery is required. There is a problem that it becomes a hindrance.

The objective of this invention is providing the secondary battery module which can avoid the burst of a secondary battery.

In order to achieve the above object, a secondary battery module of the present invention includes a secondary battery, a housing case for housing the secondary battery, an explosion-proof valve disposed in the secondary battery and having a rupture structure, and an explosion-proof valve. And a projection inscribed in the housing case.

  According to the secondary battery module of the present invention, rupture of the secondary battery can be avoided.

  Hereinafter, the secondary battery module according to the present invention will be described more specifically.

FIG. 1 is a diagram illustrating an example of a secondary battery module. A plurality of secondary batteries 1 that are continuously arranged with a space therebetween are accommodated in a case 2, and a holding plate 3 having an electrode terminal hole 3 a through which the electrode terminal 1 a of the secondary battery 1 is inserted is provided in the secondary battery 1. Mating. A connection terminal 4 having a terminal connected to the electrode terminal 1a and an external terminal for connecting to an external device (not shown) is arranged between the presser plate 3 and the protective cover 5, and the bolt 5a of the protective cover 5 is attached to the presser plate 3. It is configured to be inserted into the bolt hole 3b and fastened to the nut 2a of the case 2.

Here, the housing case refers to a portion of the secondary battery module excluding the secondary battery 1 and the explosion-proof valve 6.
For example, is disposed between both electrode terminals of the secondary battery 1 and has a protrusion which is opposed to the explosion-proof valve 6 and is provided in the presser plate 3 which is one constituent element of the housing 7.

FIG. 2 is a cross-sectional view showing the positional relationship between the explosion-proof valve 6 and the protrusion of FIG. 1, and has a pointed head at a position facing the explosion-proof valve 6 disposed in the secondary battery 1 and is contained in the housing 7. It has a structure having a projection 8 in contact therewith.

FIG. 3 is a diagram showing a state when the internal pressure is increased due to a failure of the secondary battery 1, and is a diagram showing a state where the protrusion 8 of FIG. 2 pierces the expanded explosion-proof valve 6.

When the internal temperature of the secondary battery 1 rises due to the failure of the secondary battery 1 and gas is generated inside,
The secondary battery 1 may be in a high pressure state, and the volume may expand and eventually burst. There is a possibility that the electrolytic solution, which is the internal organ of the secondary battery 1, is ejected in a high temperature state together with the gas generated inside due to the rupture in the high pressure state. In order to avoid this, the secondary battery 1 has a structure in which the explosion-proof valve 6 is broken when the internal pressure reaches a predetermined pressure, and the gas generated inside the secondary battery 1 is released to the outside, thereby preventing the explosion.

Here, the explosion-proof valve 6 has a rupture structure. The rupture structure is constituted by a flexible thin plate or a rupture disk, and has a structure that is more brittle than the outer portion other than the explosion-proof valve 6 of the secondary battery 1 and easily breaks. Since the difference between the normal area and the dangerous area of the secondary battery 1 is very close, for example, when charging, unless the charging voltage is monitored in units of several tens of mV, the change in the electrode in the secondary battery 1 and the crystal structure There is a possibility that the explosion-proof valve 6 may break down and generate heat, and a high-precision and high-quality one is required for the explosion-proof valve 6 to be surely broken.

According to the present embodiment, if the explosion-proof valve 6 is not broken even if the internal pressure of the secondary battery 1 exceeds a predetermined pressure, the explosion-proof valve 6 is perforated by the protrusion 8 as shown in FIG. Therefore, the explosion-proof valve 6 can be broken at an internal pressure within the design range, and the gas in the secondary battery 1 can be released to the outside. Therefore, the secondary battery 1 can be prevented from rupturing in a high pressure state.
Safety superior to the structure using the rupture disk described in the publication can be obtained.

Further, since the protrusion 8 is installed outside the secondary battery 1, it is not necessary to provide a space for installing the protrusion in the secondary battery 1 in order to reduce the size of the secondary battery 1, and Japanese Utility Model Publication No. 4-14850. It is possible to make it easier to reduce the size than the structure in which the cutting blade is provided in the secondary battery described in (1).

Further, the positions of the explosion-proof valve 6 and the projection 8 are not limited and can be disposed at the intended position of the design. Therefore, even when the electrolyte solution of the secondary battery 1 leaks due to the explosion-proof valve 6 being broken. It is also possible to discharge safely to the intended route.

Here, the protrusion 8 has one end toward the explosion-proof valve 6 that is pointed, rounded, or shaped like a blade, and has sharpness and strength that can pierce the explosion-proof valve 6. If the strength of the projection 8 is insufficient, the projection 8 may be damaged when a force is applied to the projection 8 in an oblique direction with respect to the central axis of the projection 8 due to expansion of the explosion-proof valve 6, for example. is there. The material of the protrusions 8 is preferably hard and highly electrically insulating, and a hard resin or metal can be used. In the case of using a metal, a paint having low electrical conductivity may be applied to the surface of the metal. Thereby, since the secondary battery 1 and the protrusion 8 can be contacted without short-circuiting, this embodiment can be applied regardless of the outer material of the secondary battery 1. Similarly, the housing 7 can be made of a hard resin or metal. When a hard resin is used, the protrusion 8 can be made of the same hard resin by integral molding. When metal is used, as a method for fixing the protrusion 8 to the housing case 7, there are screwing, welding, adhesion with an adhesive, and the like. The material of the housing | casing housing | casing 7 and the protrusion 8 and the adhering method should just be provided with intensity | strength, and are not limited to said combination.

The block diagram of the secondary battery module which shows one Example of this invention. Sectional drawing which shows the positional relationship of the explosion-proof valve 6 and protrusion 8 of FIG. The figure which shows the state which the protrusion 8 of [FIG. 2] pierces the explosion-proof valve 6. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Secondary battery 1a Electrode terminal 2 Case 2a Nut 3 Holding plate 3a Electrode terminal hole 3b Bolt hole 4 Connection terminal 5 Protective cover 5a Bolt 6 Explosion-proof valve 7 Enclosure 8 Protrusion

Claims (1)

A secondary battery, a housing case that houses the secondary battery, an explosion-proof valve that is disposed in the secondary battery and has a rupture structure, and a protrusion that faces the explosion-proof valve and is inscribed in the housing case A secondary battery module comprising:

Images