Reusable rechargeable battery

Abstract

The invention relates to a rechargeable battery comprising at least one electrochemical cell housed in a casing (12) which is fixed to a support, and an adhesive layer interposed between the casing and the support. According to the invention, it further comprises a cutting means (40) for the adhesive layer. Figure for the abstract: Fig. 2

Description

Title of the invention: Reusable rechargeable battery Technical field of the invention

[0001] The present invention relates generally to the repair and reuse in a second life of accumulator batteries.

[0002] It relates more particularly to a battery of accumulators comprising at least one electrochemical cell housed in a casing which is fixed on a support, and an adhesive layer which is interposed between the casing and the support.

[0003] It also relates to a motor vehicle equipped with such a battery of accumulators. State of the art

[0004] An electric or hybrid motor vehicle ordinarily includes an electric motor and a battery of accumulators which is specially designed to supply the electric motor with current in order to propel the vehicle.

[0005] Such a battery pack generally comprises several identical modules housed in a main compartment. Each of these modules has a casing containing a plurality of low-voltage electrochemical cells, connected to each other in such a way that the overall voltage across the battery terminals is high enough to propel the vehicle. The voltage across the terminals of such a battery can, for example, be on the order of 400 V.

[0006] It sometimes happens that one of the cells develops a defect during its life.

[0007] Furthermore, as they age, the cells lose some of their energy storage capacity, which consequently reduces the vehicle's range.

[0008] When a defect is found or when this aging becomes too significant, the solution generally used is to remove the battery and replace it with a new one.

[0009] The old battery of accumulators must then be reprocessed, for example by being recycled (by crushing the cells and then by chemical treatment to recover the precious metals) or by being reused in a second life (by reusing its cells in less demanding applications such as stationary storage of wind or photovoltaic energy).

[0010] In order for the battery to be repaired or reused, it is advisable to remove one or more modules from the main compartment. Unfortunately, this removal often proves difficult. Thermal paste (more commonly known as "gap filler") is generally applied between the casing of each module and the bottom of the main compartment.

[0011] Now, not only does this paste naturally possess adhesive properties but also Furthermore, after several years, the thermal paste dries out so thoroughly that the modules become very firmly stuck to the bottom of the main tray, making their removal difficult. This is all the more problematic because the thermal paste layer is hard to access. Consequently, there is a risk of damage to the modules and electrochemical cells.

[0012] Therefore, for safety reasons, the modules are often discarded rather than reused. Presentation of the invention

[0013] In order to remedy the aforementioned drawback of the prior art, the present invention proposes a solution facilitating the disassembly of a battery of accumulators.

[0014] More particularly, the invention proposes a battery of accumulators as defined in the introduction, in which at least one means for cutting the adhesive layer is provided natively.

[0015] In other words, the battery pack incorporates means for cutting the adhesive layer of thermal paste. These cutting means can then be arranged to facilitate cutting this layer, thus preventing any damage to the module during disassembly and allowing its safe reuse.

[0016] The invention has another advantage of being very simple to implement, very inexpensive, lightweight and compact.

[0017] It can be used in any type of accumulator battery, in particular in those described above having modules, but also in those without modules, in which the cells are directly fixed in the main tray (this type of battery being better known under the English name "cell-to-pack").

[0018] The cutting means are preferably fixed directly to the battery casing (so as not to disrupt the conventional process of mounting the modules in the main tray). Alternatively, they could be embedded in the adhesive layer.

[0019] Other advantageous and non-limiting features of the accumulator battery according to the invention, taken individually or in all technically possible combinations, are as follows: - said cutting means includes gripping means accessible by an operator, preferably from the side of the casing opposite the support; - said cutting means comprises at least one flexible wire; - said gripping means include, at at least one end of the flexible wire, a ring preferably accessible from the side of the housing opposite the support; - means are provided for holding the flexible wire on the housing, adapted to give way when a tensile force greater than a predetermined threshold is exerted on the flexible wire; - the flexible thread extends along at least part of the periphery of the adhesive layer; - suitable guiding means are provided to guide the sliding of the flexible wire when a tensile force is exerted on the flexible wire; - the guiding means include at least one loop fixed to the housing and through which the flexible wire passes; - the housing includes, at one end, an electrical connection module comprising an end wall; - the guiding means include two holes for the flexible wire located in the end wall.

[0020] The invention also relates to a motor vehicle comprising drive wheels, a powertrain which is adapted to be coupled to said drive wheels and which includes at least one electric motor, and a battery of accumulators as above, electrically connected to said electric motor.

[0021] Of course, the various features, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0022] The following description with regard to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be carried out.

[0023] On the attached drawings:

[0024] [Fig-1] is a schematic side view of part of a battery of accumulators;

[0025] [Fig.2] is a schematic perspective view of the underside of a battery module conforming to a first embodiment of the accumulator battery of [Fig.1]

[0026] [Fig.3] is a schematic perspective view of the underside of a battery module according to a second embodiment of the accumulator battery of [Fig.1].

[0027] In [Fig.1], a part of a battery of accumulators 1 is shown.

[0028] This battery pack is here more specifically designed for use in a mobile application.

[0029] In practice, this refers to a battery pack 1 installed in an electric or hybrid motor vehicle. This battery is specifically designed to supply electric current to an electric propulsion motor of the vehicle.

[0030] This accumulator battery 1 comprises at least one main tray and electrochemical cells 11 housed in the tray.

[0031] The main tank has a base 20, illustrated in [Fig. 1], which serves as a support. Preferably, this base 20 incorporates a coolant circulation channel, allowing the heat emitted by the electrochemical cells 11 to be dissipated to the outside.

[0032] It could be envisaged that the electrochemical cells 11 are directly fixed to the base 20, in a so-called “cell-to-pack” configuration.

[0033] However, here, these cells are distributed by modules.

[0034] Each module 10 thus comprises a housing 12 which accommodates several electrochemical cells 11 and which is installed on the bottom 20.

[0035] Fastening means are generally used to fix the housings 12 of the modules 10 to the base 20. These fastening means are generally screwing means (typically bolts), but alternatively they could be different means, typically snap-on means.

[0036] In practice, the housing 12 of a module 10 has a parallelepiped box shape.

[0037] As shown in [Fig.2], the housing 12 thus comprises six assembled walls, including two upper walls 121 and lower walls 122 (located on the bottom side 20), two side walls 123, 124, and two end walls 125, 126.

[0038] In the following, it will be considered that the bottom 20 of the main tray extends substantially horizontally and that the housings 12 of the modules 10 rest on this bottom 20 by their lower faces 122.

[0039] As shown in [Fig.1], the electrochemical cells 11 are arranged in this case in parallel with each other, parallel to the side walls of the case.

[0040] They are connected together using electrical connectors (not visible). These electrical connectors are located here against one of the end walls 125.

[0041] In the example of [Fig.3], this end wall 125 is thick so that it houses these electrical connectors, the latter then forming with this end wall 125 a connection block.

[0042] The walls of the housing 12 of each module 10 are here made of aluminium and / or plastic and / or steel and / or composite materials (for example carbon fibres embedded in a resin).

[0043] During their use, and in particular during their recharging, the electrochemical cells 11 heat up considerably, and it becomes necessary to conduct the heat thus emitted to the outside of the main tank.

[0044] It is within this framework that the housing 12 of each module 10 is fixed to the base 20 of the main tank via a 30mm layer of thermal paste.

[0045] This layer 30 is designed to fill the irregularities of the surfaces of the bottom 20 of the main tray and the underside of the housing 12, so as to optimize heat exchange between these elements. It also has adhesive properties so that it contributes to securing the housing 12 to the bottom 20 (in addition to the aforementioned bolts). Furthermore, it provides a vibration damping function to reduce the vibrations experienced by the housing when the motor vehicle is in motion.

[0046] This layer is preferably continuous, but it could have discontinuities (it could have holes or be formed of distinct sections located at a distance from each other).

[0047] The adhesive properties of this layer 30 of thermal paste are such that it often proves difficult to disassemble the housings 12 from the base 20.

[0048] In order to facilitate this disassembly, means for cutting 40 of this layer 30 of thermal paste are provided here.

[0049] As shown in [Fig.2], these cutting means 40 here mainly comprise a flexible wire 41 and means for gripping this wire.

[0050] This wire 41 is shaped to slice through the layer 30 of thermal paste when the gripping means are actuated.

[0051] In practice, this wire 41 is described as flexible since it can be manually bent at a right angle.

[0052] Its gripping means are formed by its ends, which are arranged so as to be accessible by the operator. Preferably, they are then accessible from the top of the housing 12. Of course, alternatively, they could be accessible otherwise, for example from a side of the housing.

[0053] Thus, when a force is exerted on at least one of the ends of the wire 41, the latter is intended to cut the layer 30 of thermal paste and detach the housing 12 from the base 20.

[0054] It is thus possible to easily cut layer 30 even when several modules are located next to each other and access below these modules 10 is impossible.

[0055] In practice, here, the wire 41 is fixed to the lower wall 122 of the housing 12 (thermal paste layer 30 side). It extends along three of the four sides of this lower wall (preferably along the two side walls and one of the end walls). It is thus folded into a U-shape on this wall. In this way, when an operator pulls manually or with the aid of a machine on the two ends of the wire 41, the latter moves along the entire outer face of this lower wall 122, which makes it possible to cut through all or almost all of the thermal paste layer 30. thermal paste.

[0056] In practice, the peripheral part of the thermal paste layer 30 may remain if the wire does not exactly border the lower wall. But in this case, the remaining thermal paste will be easily detachable (because the residual adhesive force will then be very weak since little surface area will have remained glued).

[0057] The wire 41, in order to be accessible from above, also extends along the end wall 125 and protrudes on top of the housing 12. The two ends of the U are more precisely folded to run along the two sides of the end wall 125.

[0058] Means are then provided for holding the wire 41 in the position described above.

[0059] These means of support 50 can take various forms.

[0060] Here, and preferably, it refers to pieces of adhesive tape, for example of the Scotch® type, which allow the wire 41 to be glued onto the housing 12.

[0061] Alternatively, drops of glue could be used for the same purpose. As another alternative, the wire could be coated with adhesive so as to automatically stick to the housing 12. As yet another alternative, clips could be used.

[0062] In all cases, these retaining means 50 are designed to release the wire 41 when a significant tensile force is exerted on at least one of its ends.

[0063] The objective is for these retaining means 50 to block the wire 41 if a small force is accidentally exerted on it, but to release the wire 41 so that it can cut through the thermal paste layer 30 if a force exceeding a threshold is exerted on at least one of its ends. This threshold is, for example, around ten Newtons.

[0064] When a force is exerted on the ends of the wire 41, it is preferable that the wire slide along the lower wall 122 of the housing 12 and the end wall 125. In other words, we seek to prevent the wire 41 from escaping along one of the side walls 123, 124 of the housing 12.

[0065] It is then preferably provided that means are provided for guiding the sliding of the wire 4L. These guiding means are arranged to form systems for returning the wire 41 to the top of the module 10.

[0066] In the embodiment illustrated in [Fig.2], these are loops, and more specifically eyelets 13 which are fixed, for example by welding, to the end wall 125 of the housing 12.

[0067] These eyelets 13 are preferably provided at the height of the lower wall 122 of the housing 12 (or at least closer to it than to the upper wall 121).

[0068] Two eyelets 13 are used here to guide the sliding of the two ends of the wire 4L. These two eyelets 13 are located at the junction between the lower walls 122, lateral walls 123, 124 and end wall 125 of the housing 12.

[0069] In the embodiment of [Fig. 3], the wire guiding means 41 are directly integrated into the end wall 125 of the connection block, which is thick and has two through holes 15. These two holes are, for example, drilled into the wall or formed by a molding operation of this wall. They extend along axes parallel and orthogonal to the plane of the lower wall 122.

[0070] The means for gripping the wire 41 are here formed by two loops 42 located at the two ends of this wire 41. It is thus possible to pull on the wire 41 using two hooks attached to these loops 42, or using a bar passed through these two loops 42.

[0071] Here, the wire 41 used is, for example, a metallic cable sheathed in electrically insulating material. It has a diameter less than or equal to the thickness of the thermal paste layer 30. In practice, it has a diameter of approximately 1 mm when the layer 30 has a thickness of 2 to 3 mm.

[0072] Alternatively, it could be made of another material, such as Nylon. Preferably, it will be formed from a set of braided filaments, for example of Kevlar® or Dyneema®.

[0073] In practice, the wire 41 is installed by the manufacturer of the module 10, once the rest of the module is already assembled. To prevent the loops 42 from unintentionally catching on anything during the transport of the module or the assembly of the battery 1, pieces of adhesive are used to fix these loops 42 to the outer face of the upper wall 121 of the housing 12.

[0074] The module is then delivered in this configuration to the vehicle assembly machining. To be installed in the vehicle, the bottom 20 of the main tray (or the external face of the lower wall 122 of the module) is coated with the layer 30 of thermal paste, then the module is placed on the bottom 20 of the main tray and screwed to it using the bolts.

[0075] When the battery accumulator 1 needs to be removed, an operator hooks the two loops 42 of the wire 41 of the module 10 in question, then exerts a pulling force on the wire 41, which allows the latter to slide through the layer 30 of thermal paste in order to detach the module 10 from the base 20. The operator then unscrews the bolts to remove the module 10.

[0076] This solution is therefore not destructive to the module 10, which can then be reused as is in other applications, for example for stationary energy storage. Indeed, this solution does not damage the module because virtually no stress is applied to it during the cutting phase of the thermal paste layer.

[0077] The present invention is in no way limited to the embodiment described and illustrated, but a person skilled in the art will be able to make any variation therein in accordance with the invention.

[0078] Typically, it would be possible to fix one end of the wire so that to cut the layer of thermal paste, it is enough to pull on the other end of the wire.

[0079] Alternatively, the wire could be without loops at its ends (the wire then having to be gripped by pliers or wound around a rod to allow the thermal paste layer to be cut).

[0080] Alternatively, the housing could be without guiding means. In this case, the tension exerted on the ends of the wire must be in precise directions to prevent the wire from slipping out of the housing.

[0081] According to another embodiment, if the battery is module-less (in the so-called "cell-to-pack" configuration), each electrochemical cell would have its own casing, generally parallelepiped-shaped. Each cell could then be equipped with its own wire. Alternatively, a single wire could be installed on the bottom of the main tray, so that it alone could cut through the layers of thermal paste located under all the electrochemical cells. As a further alternative, several wires could be installed on the bottom of the main tray, so that each could cut through the layers of thermal paste of several separate electrochemical cells.

[0082] Finally, it should be noted that while the described accumulator battery 1 is well suited for cars, it could also be used in agricultural machinery, aeronautical or space equipment, heavy goods vehicles, defense vehicles, ships and even in stationary applications.

Claims

Demands

1. Accumulator battery (1) comprising at least one electrochemical cell (11) housed in a casing (12) which is fixed to a support (20), and an adhesive layer (30) which is interposed between the casing (12) and the support (20), characterized in that it further comprises a cutting means (40) for the adhesive layer (30), which includes gripping means accessible by an operator from the side of the casing opposite the support.

2. Accumulator battery (1) according to claim 1, wherein said cutting means (40) comprises at least one wire (41).

3. Accumulator battery according to claim 2, wherein said gripping means comprise, at at least one of the ends of the wire (41), a ring (42) accessible from the face of the housing (12) opposite the support (20).

4. Accumulator battery according to any one of claims 2 and 3, wherein there are provided means for retaining (50) the wire (41) on the casing (12), adapted to give way when a tensile force greater than a predetermined threshold is exerted on the wire (41).

5. Accumulator battery according to any one of claims 2 to 4, wherein the wire (41) extends along at least a part of the periphery of the adhesive layer (30).

6. Accumulator battery according to any one of claims 2 to 5, wherein there are provided guiding means (13, 15) adapted to guide the sliding of the wire (41) when a tensile force is exerted on the wire (41).

7. Accumulator battery according to claim 6, wherein the guiding means (13) comprise at least one loop fixed to the housing (12) and through which the wire (41) passes.

8. Accumulator battery according to any one of claims 1 to 7, wherein the housing (12) comprises, at one end, an electrical connection module including an end wall (125).

9. Accumulator battery according to claims 6 and 8, wherein the guiding means (15) comprise two wire passage holes (41) located in the end wall (125).

10. A motor vehicle comprising drive wheels, a powertrain adapted to be coupled to said drive wheels, and comprising at least one electric motor, characterized in that it further comprises a battery of accumulators (1) conforming to one of the preceding claims, electrically connected to said electric motor.

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