FR2625372A1 - Alkaline electrochemical generator equipped with a spring - Google Patents

Abstract

An electrochemical generator with a cylindrical container 11 enclosing, from the outside inwards, a peripheral cathode 12, a separator 13, an anode 14 of alkali or alkaline-earth metal, a spring 15 pushing the anode against the separator, characterised in that this spring 15 is made up of two diametrically opposed blades 15A, 15B attached by one of their ends to a central terminal 16. Application to alkaline generators.

Description

Alkaline electrochemical generator equipped with a spring.

 The present invention relates to an electrochemical generator with a cylindrical cup containing an anode of alkali or alkaline earth metal.

 Some of these types of generators require the presence of a spring which constantly pushes this anode, so that it is always in contact with the separator. In fact, during discharge, this anode of alkali or alkaline earth metal wears out and the spring compensates for this wear when the cathode does not increase enough volume.

 We know, from document FR 2.556.506, such a generator comprising an anode of this type pushed by a spring.

 This spring is a split tube inserted in the center of the anode and its length is practically identical to that of the anode.

This form of spring does not ensure a constant thrust on the anode as it wears so that some generators, around 10%, present large voltage drops before the end of discharge, which limits their lifespan.

 The purpose of the spring of the present invention is to eliminate these voltage drops and thus ensure for all generators a minimum dispersion in capacity.

 The subject of the present invention is an electrochemical generator with a cylindrical cup containing, from the outside to the inside, a peripheral cathode, a separator, an anode of alkali or alkaline earth metal, a spring pushing the anode against the separator, characterized in that this spring consists of two diametrically opposite blades and fixed by one of their ends to a central terminal.

 -According to an advantageous characteristic ensuring a constant elastic deformation of the spring, the other end of the two blades of the spring is a free end, these two free ends bearing and pivoting one against the other during the deformation of the spring.

 According to two embodiments, the two blades are two separate parts or the two blades are in one piece.

 An electrochemical generator according to the invention is described below, by way of example and with reference to the accompanying drawings.

 Figure 1 shows this generator in longitudinal section.

 Figure 2 shows a spring in perspective.

 Figure 3 shows three embodiments of the spring.

 Figure 4 shows a compressed spring ready to be inserted in the center of a generator.

 FIG. 5 shows curves each giving the discharge of a battery.

 In FIG. 1, the generator 10 mainly consists of a bucket 11 enclosing from the outside towards the center, an annular cathode 12, a separator 13, an annular anode 14 and finally a spring 15 composed of two blades 15A, 15B .

 This spring 15, better visible in FIG. 2, is connected to a central terminal 16 which is isolated from the cover 18 by an insulator 17.

 The electrical contact between the anode 14 and the terminal 16 is ensured by the spring 15 but also by a connection 19 welded on the internal face of the anode 14 on the one hand and on the terminal 16 on the other hand.

 Conventionally, the electrical contact can be ensured only by the welded connection 19, the spring then playing only a mechanical role.

 FIG. 2 shows the particular shape of the spring composed of two identical blades 15A, 15B, these two blades being connected together by their fixed end, to form a spring in a single piece welded to the terminal 16.

 The other end of each of the blades is free and has a flat 25. These two free ends can be, at rest, contiguous or not.

 FIG. 3 shows in A, the embodiment described in FIG. 2. It shows in B, another embodiment in which the two blades 15A, 15B are two separate parts, rigidly connected by welding, or any other conventional means, at terminal 16.

Finally, it shows in C, curved blades, this variant being adaptable to cases A and B.

 FIG. 4 represents a compressed spring, the pinching making it possible to introduce it into the anode. The two blades pivot one on the other, at point P. This pivoting better distributes the stiffness all along the spring and ensures a reversible elasticity. Indeed, during its introduction into the anode, the spring does not undergo any permanent deformation and once installed inside the anode, it regains its own elasticity and ensures a constant thrust on the anode. The discharge life is therefore no longer dependent on the quality of the spring and is therefore almost constant.

 The curves in FIG. 5 show discharge results obtained with CEIR6 format batteries (height: 50 mm, diameter 13.5 mm), and under the following discharge conditions: ambient temperature, under constant resistance of 1000 ohms.

 The discharge time is given on the abscissa and the voltage on the ordinate. The dispersion in capacity is low from one cell to another and for each cell the voltage is kept constant until the end of discharge.

 The installation of this spring can be done through a template, so that it is easily automated. Automatic installation will also ensure constant pressure on all springs and completely eliminate the risk of permanent deformation.

Claims (4)

1 / Electrochemical generator with cylindrical cup (11) containing, from the outside to the inside, a peripheral cathode (12), a separator (13), an anode (14) of alkali or alkaline earth metal, a spring (15) pushing the anode against the separator, characterized in that this spring (15) consists of two blades (15A, 15B) diametrically opposite and fixed by one of their ends to a central terminal (16). 2 / generator according to claim 1, characterized in that the other end of the two blades of the spring is a free end, these two free ends bearing and pivoting one on the other during the deformation of the spring. 3 / Generator according to claim 2, characterized in that the two blades are two separate parts. 4 / Generator according to claim 2, characterized in that the two blades are in one piece.