FR2943853A1 - Electrochemical generator e.g. lithium-ion electrochemical generator, assembling method for battery, involves bracing maintaining element on side wall of cylindrical container of electrochemical generator - Google Patents

Abstract

The method involves bracing a maintaining element i.e. circular maintaining ring (20), on a side wall (14) of a cylindrical container (12) of an electrochemical generator (10) by heating the maintaining element and introducing the maintaining element on the container, where the container is provided with a cover (16) and a bottom (18), and the container and the maintaining element are made of aluminum. An independent claim is also included for a battery comprising an electrochemical generator.

Description

ELECTROCHEMICAL GENERATOR AND BATTERY ASSEMBLY METHOD

The present invention relates to the field of electrochemical generators and a method of assembling battery electrochemical generators. An electrochemical generator or accumulator (these two terms being equivalent, the term "generator" will be used in the present description) comprises in known manner an electrochemical bundle comprising an alternation of positive and negative electrodes surrounding electrolyte impregnated separators. Each electrode is composed of a metal current collector supporting on at least one of its faces the electrochemically active material. The electrode is electrically connected to a current output which provides electrical continuity between the electrode and the external application to which the generator is associated. The electrode beam is disposed in a container closed by a lid. In order to increase the power and / or the energy available from electrochemical generators, it is known to associate several generators by connecting them in series and / or in parallel. Battery means such an assembly of generators. Several means exist to mechanically maintain the assembly of 20 battery electrochemical generators. Typically, a plurality of generators can be maintained by one or two flanges providing mechanical support and the terminals of the generators are electrically connected according to the desired scheme (series and / or parallel) by power connection strips. The mechanical maintenance of the generators in flanges or other supports 25 can be provided for example by gluing, resealing or welding. It is also known from US-A-2005/0196665 a method of battery assembly using connecting rings. But these techniques do not allow easy disassembly of the generators placed in the battery. This makes replacing a battery generator difficult or impossible. There are batteries in which the generators are inserted in honeycomb structures. A resin step allows the mechanical maintenance of these elements in the honeycomb structure. A battery of this type is marketed by the applicant under the reference Lithium battery 2 x 6 P W3A. Such a resins process is slow to implement and makes it difficult to dismantle the generators. There is therefore a need for a method of assembling electrochemical battery generators which is easy to implement while allowing easy disassembly or replacement of the assembled generators.

For this purpose, the invention provides a method for assembling battery electrochemical generators. , each electrochemical generator having a container with a side wall, a bottom and a lid, the method comprising a step of shrinking a holding member on the side wall of the container.

According to one embodiment, the shrinking step comprises the steps of heating the holding member, the container being maintained at ambient temperature, and introducing the holding member onto the container. According to one embodiment, before the introduction step and at room temperature, the holding member has an inner perimeter which is smaller than the outer perimeter of the container. According to one embodiment, the holding element and the container are made of the same material; for example aluminum. The invention also relates to an electrochemical generator comprising a container with a side wall, a bottom and a lid, a holding member 15 being hooped to the side wall of the container. According to one embodiment, the holding element is a ring and the container is cylindrical. According to one embodiment, the bottom of the container is adapted to tear under the effect of an overpressure in the container. The invention further relates to a battery of electrochemical generators comprising: - at least one flange comprising a plurality of cells, - a plurality of electrochemical generators according to the invention. each generator being positioned in a cell with its holding member in abutment on a retaining element arranged in the cell. According to one embodiment, the detachment of the bottom of each container is not impeded by the retaining element of the generator in the cell. According to one embodiment, the retaining element is a ring housed in an opening of the cell or clipped on an opening of the cell. Other features and advantages of the invention will appear on reading the following detailed description of the embodiments of the invention, given by way of example only and with reference to the drawings which show: FIG. diagram of an electrochemical generator according to the invention; FIG. 2 is a diagram of a plurality of electrochemical generators assembled in a battery according to the invention. The invention relates to an electrochemical generator and more specifically to a method for assembling electrochemical generators in the form of electrochemical generators. drums. Figure I illustrates a generator according to the invention. The generator 10 comprises a container 12. The container 12 comprises a side wall 14, a bottom 18 and a lid 16. The generator also comprises a holding element 20 hooped on the side wall 14 of the container 12. The holding element 20 may be a ring if the container 12 is cylindrical, but other shapes may be considered as a rectangular ring if the container is prismatic. Figure 1 shows a circular retaining ring.

The inner perimeter of the holding member 20 may be smaller than the outer perimeter of the container 12. This can easily be achieved at the time of machining the holding member and the container 12. This provides a better fit. clamping the holding member 20 on the side wall 14 of the container 12. The assembly method according to the invention comprises a step of shrinking a holding member 20 on the side wall 14 of the container 12. The element holding 20 will allow the mechanical strength of IO generators during battery assembly. The implementation of such a method comprising a shrinking step is simpler than a bonding of the ring or a resin electrochemical battery battery. In particular, the cycle time for assembling battery generators according to the process of the invention is reduced to a few minutes whereas resinsation involves longer cycle times of the order of 24 to 72 hours because of the polymerization time. resins used. The holding tools in the assembly position can also be eliminated due to the reduction of the cycle time. In addition, the constraints related to the use of resins or glues are avoided. Thus, the staff is no longer exposed to harmful vapors related to the work of resins or glues. In particular, it becomes possible to refrain from the use of suction means such as extractor hoods and the individual protection of each staff member via a mask for this assembly operation battery generators. The absence of glue or resin also limits non-recyclable waste during dismantling of the battery at the end of its life. According to one embodiment, in order to carry out the shrinking of the holding element 20 on the container 12 of the generator 10, the holding element 20 is heated, which causes thermal expansion to position it on the container 12 which has kept at room temperature. The holding element 20 cools in contact with the container and convection air and contracts to tighten the container 12 of the generator 10. Contrary to what was thought so far, the application of an element to high temperature, for example around 300 ° C. on the R 13re, rI, 2960N1C963 '- 1191) 3] 4-trxte dep ", id ,,' 3: 1 3n, container 12 does not damage the electrochemical generator 10 and in particular the electrochemical beam, because the skin temperature of the container 12 does not exceed 80 ° C. for a very short time, the holding element and the container 12 can be made of the same material, which makes it easier to control the process because the For example, the material chosen for the holding member and the container 12 may be aluminum, which is particularly advantageous because the coefficient of elasticity is the same for the holding member and the container 12. Thermal expansion of the aluminum is important which limits the heating to be applied to the holding element and increases the mounting clearance available to the operator implementing the assembly process. advantage of well dissipated heat, which allows the process to be carried out more quickly. Other materials may however be used, such as copper or steel.

Such a method makes it possible to obtain an electrochemical generator 10 as illustrated in FIG. 1. The holding element 20 is hooped on the lateral wall of the container 12. Once secured by hooping, the holding element 20 resists to traction. Thus, the element 20 will maintain the electrochemical generator between two battery flanges.

Such a generator may be part of a battery 22 of electrochemical generators 10 as illustrated in FIG. 2. According to the illustrated embodiment, the battery 22 comprises two flanges 24 comprising a plurality of cells 26, the two flanges 24. being connected by a retaining ring 30. The flanges 24 may for example be made of aluminum because aluminum is a lightweight and easily machinable material. The flanges 24 may, however, be composed of another material, such as plastic for example. The battery 22 further comprises a plurality of electrochemical generators 10 as described with reference to FIG. 1. Each generator 10 is positioned in a cell 26 with its element 20 holding in abutment on a retaining element 28 arranged in the cell 26. The retaining element 28 thus bears on the holding element 20 of the generator to prevent the generator 10 can slide in the cell 26. The generators 10 are thus well maintained in their respective cell 26 and therefore in In addition, it is easy to replace a battery generator 22 when the generator is damaged or malfunctions independently of the other generators 10 of the battery 22 and without having to disassemble the battery 22 in its entirety. , the generators 10 being accessible from the outside, after disassembling the flanges.

R1Bresctst296 (1 V? 963: - (H1, .4-texic de {ra Jo .. 4; 3 I4 3 - 4/8 The retaining element 28 can be a plastic ring housed in an opening of the cell 26 or clipped on an opening of the cell 26 or on a return of the wall of the cells inwards According to one embodiment, the holding element 20 of the generator 10 is sufficiently far from the bottom 18 of the container 12 to guarantee that the bottom 18 is not impeded by the retaining element 28 of the generator 10 in the cell 26. It is thus possible that the bottom 18 can tear without damaging the flange 24 in case of overpressure in the generator 10 A generator 10 is generally designed to operate under so-called nominal conditions, i.e. within given temperature, current and voltage ranges.Use of the generator 10 out of nominal conditions, such as accidental overload , a short circuit, a temperature above the t maximum operating temperature, etc., poses a safety problem. Indeed, such situations lead to a heating of the electrolyte and the formation of electrolyte vapors. The accumulation of these vapors in the container 12 causes an increase in the internal pressure of the generator 10, which can lead to a violent bursting of the container 12 and the projection of harmful chemical compounds and corrosive to the environment and people located in proximity. To alleviate this problem, the bottom 18 of the container 12 can be adapted to tear under the effect of an overpressure in the container 12. This is made possible, for the generator 10 of FIG. 1, by the fact that the maintenance is performed by the element 20 disposed on the side wall 14 which does not hinder the tearing of the bottom 18 when compliance with the safety conditions for the generator 10 requires. An example of implementation may be a thinning 32 provided on the side wall 14 as shown in Figure 1. The thinning 32 is placed near the bottom 18 of the container 12. The thinning 32 is adapted to be torn by an overpressure inside the container 12. The element 20 is disposed on the side wall 14 sufficiently far from the thinning 32 so as not to hinder the tearing of the thinning 32 and then the detachment of the bottom 18 of the container 12.

The method according to the invention allows quick and easy assembly of battery generators. The present invention is not limited to the embodiments previously described by way of example. In particular, the process may concern any type of electrochemical generator and in particular nickel-cadmium, nickel-metal hydride and lithium-ion. Such generators 10 may be of cylindrical or rectangular format (also known as prismatic). The choice of materials depends on the intended applications. R V3rcvcnC96181C9632u i ^ 9U324-icxtc dEpirt doc - 24413/119 - 14 03 - 58

Claims (10)

REVENDICATIONS1. A method of assembling generators (10) CLAIMS1. A method of assembling electrochemical battery generators (10), each electrochemical generator (10) having a container (12) with a side wall (14), a bottom (18) and a cover (16), the method comprising a step of shrinking a member (20) for holding on the side wall (14) of the container (12). 2. The method of claim 1, wherein the shrinking step comprises the steps of: - heating the holding member (20), the container (12) being maintained at ambient temperature, - introduction of the element (20) for holding on the container (12). The method of claim 2, wherein, prior to the introducing step and at ambient temperature, the holding member (20) has an inner perimeter which is smaller than the outer perimeter of the container (I2). 4. The method according to one of claims 1 to 3, wherein the element (20) for holding and the container (12) are made of the same material. The method of claim 4, wherein the material is aluminum. An electrochemical generator comprising a container (12) with a side wall (14), a bottom (18) and a lid, a holding member (20) being hooped to the side wall (14) of the container (12). The electrochemical generator of claim 6, wherein the holding member is a ring and the container is cylindrical. 8. The electrochemical generator according to claim 6 or 7, wherein the bottom (18) of the container (12) is adapted to tear under the effect of an overpressure in the container. 9. A battery of electrochemical generators (10) comprising: - at least one flange (22) comprising a plurality of cells (26), - a plurality of electrochemical generators (10) according to one of claims 6 to 8. R VBrescisV296O {V2963 '---- 09 (1324-iexle deposit .Juc - 24/03/09 - 1 d 4chaque generator (10) being positioned in a cell (26) with its element (20) for holding in abutment on a retention element (28) arranged in the cell (26). 10. A battery of electrochemical generators (10) according to claim 9, wherein the detachment of the bottom (18) of each container (12) is not impeded by the element (28) for retaining the generator (10) in the cell (26). He. A battery of electrochemical generators (10) according to claim 9 or 10, wherein the retaining element (28) is a ring clipped on an opening of the cell (26). 12. A battery of electrochemical generators (10) according to claim 9 or 10, wherein the retaining element (28) is a ring housed in an opening of the cell (26). RABreetts \ 29fi00A29632 - X190774-1,1t Jtlri Ao. _4 '^ 3' (h - 14. ri) - 7'N