JPS6213329Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a battery in which a battery component is hermetically sealed within a case, and an object thereof is to prevent the battery characteristics from changing even if the case is deformed due to an increase in internal pressure within the case.

For example, when an example of the conventional structure of a lithium battery is shown in FIGS. 1 and 2, 1 is a metal case with a bottom and an opening at the top, 2 is the battery assembly housed in the case 1, and 3 is the top end of the case 1. The lid has a hermetic seal structure that seals the opening. The case 1 is composed of a flat bottom plate 1a, a cylindrical side plate 1b, and a flange portion 1c extending outward from the upper end of the side plate 1b. The lid body 3 includes a relatively thick metal ring 4 and an electrode extraction terminal, for example, a negative electrode terminal 7, which is hermetically sealed in a hole 5 formed in the center of the metal ring 4 through a glass 6. Consists of metal ring 4
Thin wall portion 4' on the peripheral edge of the case 1 and the flange portion 1 of the case 1
c are hermetically fixed by cold pressure welding, for example.
The battery structure 2 has a structure in which the following 8 to 12 flat plate components are stacked from the bottom plate 1a of the case 1, and 8 is a positive electrode current collector made of nickel or titanium, etc.
9 is a positive electrode layer such as manganese dioxide or graphite fluoride, 10
11 is a lithium negative electrode layer, and 12 is a negative electrode current collector such as nickel net or expanded nickel. This battery assembly 2 is hermetically sealed with a case 1 and a lid 3, and a suitable insulator 13 is filled between the side plate 1b of the case 1 and the lid 3. In addition, the positive electrode current collector 8 of the battery structure 2 and the case 1
are in electrical contact, and the case 1 itself is used as a terminal for taking out the positive electrode. Further, when the battery assembly 2 is sealed with the case 1 or the lid 3, the pressing force between the positive and negative electrodes is kept constant, and the battery assembly 2 is adjusted to have predetermined electrical characteristics.

However, the internal pressure of the battery may increase due to an increase in the outside temperature or the generation of reactive gases due to chemical reactions during operation. Therefore, if the battery assembly 2 is tightly sealed with the case 1 and the lid 3, there is a risk that the case 1 will explode due to the increase in internal pressure.
To prevent this explosion, the case 1 is made of copper, which has a relatively low strength, and when the internal pressure rises, the flat bottom plate 1a of the case 1 bulges outward as shown by the dotted line in Figure 1, thereby preventing an explosion.
Another reason for using copper for the case 1 is that it is advantageous when cold pressure welding the flange portion 1c of the case 1 to the metal ring 4 of the cover 3, for example.

In this way, conventionally, in order to prevent a case from exploding due to an increase in internal pressure, the strength of a part of the case 1, that is, the flat bottom plate 1a, has been weakened, and the increase in internal pressure has been absorbed by the deformation of this bottom plate 1a. However, when the bottom plate 1a swells due to an increase in internal pressure, a gap is created between the bottom plate 1a and the battery assembly 2, and the pressing force of the bottom plate 1a against the battery assembly 2 is weakened, causing the upper and lower parts of the battery assembly 2 to The pressing force between the positive and negative electrodes decreased, and as a result, the internal resistance of the battery structure 2 increased, resulting in changes in battery characteristics.

The present invention has been made in view of the above-mentioned conventional problems and has solved them, and provides a battery in which the pressing force on the battery structure does not change even if the case is deformed due to an increase in internal pressure. For example, an example in which the present invention is applied to the above lithium battery is shown in FIG. 3. The same reference numerals as in FIG. 1 indicate the same contents as in FIG. A relatively strong reinforcing plate 14 is interposed between the structural bodies 2.

This reinforcing plate 14 is formed of a metal disk having an outer diameter approximately the same as the inner diameter of the side plate 1b of the case 1. After the reinforcing plate 14 is fitted onto the bottom plate 1a of the case 1, the battery current collector 2 is housed thereon and hermetically sealed with the lid 3. Incidentally, the case 1 used is one in which the bottom plate 1a deforms when the internal pressure rises to prevent an explosion, as in the conventional case.

When the reinforcing plate 14 is interposed between the bottom plate 1a of the case 1 and the battery structure 2 as described above, when gas is generated from the battery structure 2 and the internal pressure rises, the case 1 When internal pressure is applied to the bottom plate 1a of the bottom plate 1a, it bulges outward as in the conventional case, but since the reinforcing plate 14 does not deform due to the same internal pressure being applied to both sides, the bottom plate 1a of the bottom plate 1a bulges outward as shown in FIG. Regardless of the deformation, the reinforcing plate 14 supports the battery assembly 2 from below in its original state. Therefore, the thickness between the positive and negative electrodes of the battery structure 2 does not change, and the pressing force between the positive and negative electrodes remains the same, so the battery characteristics do not change. Further, although a gap g is formed between the reinforcing plate 14 and the deformed bottom plate 1a, this gap g only collects reactive gas and the like, and there is no problem with the battery characteristics.

It should be noted that the present invention is not limited to lithium batteries, but can be fully applied to other generally hermetically sealed batteries.
Furthermore, the battery case is not limited to a cylindrical shape with a bottom, and may be, for example, a rectangular cylindrical shape with a bottom, as long as the bottom expands when the internal pressure increases. A reinforcing plate is installed between the bulging (deformed) portion and the battery structure.

As explained above, according to the present invention, even if the case is deformed due to an increase in internal pressure, the battery structure is protected by the reinforcing plate and does not deform, so the battery characteristics are always stable and reliability is improved. can be achieved.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an example of a conventional battery;
1 is a plan view of the battery, FIG. 3 is a sectional view showing an embodiment of the battery according to the present invention, and FIG. 4 is a sectional view illustrating the case of the battery shown in FIG. 3 when the case is deformed. 1... Case, 2... Battery structure, 14... Reinforcement plate.

Claims (1)

[Scope of Claim for Utility Model Registration] In a battery in which a battery assembly is enclosed in a case in which a metal case with a bottomed top opening and a lid with a hermetically sealed structure are hermetically sealed, the metal case includes: The bottom plate is strong enough to be expanded and deformed by an increase in internal pressure of the case, a metal reinforcing plate is interposed between the bottom plate of the metal case and the battery structure, and the battery structure is pressed by this metal reinforcing plate. A battery characterized by: