Electrical connection device comprising a busbar and at least one compressible element, released by melting of an MCP material to ensure an electrical connection of at least one accumulator of a battery module or battery pack.

Abstract

The invention relates to an electrical connection device (10) for electrically connecting at least one electrochemical accumulator, comprising: - a busbar (11), one face of which includes at least one electrical connection surface (110), - at least one mechanical guide piece (12) adapted to guide the busbar, and thereby the connection surface, in translation along a direction (Z) in which the accumulator extends, - at least one compressible element (14) arranged on the other face of the busbar, - at least one phase-change material (PCM) block forming a spacer (13), the change of which from solid to liquid state releases and moves the compressible element from one compressed state to another, in which it is intended to bring the connection surface into contact with an output terminal of an accumulator. Figure for the abstract: Fig. 6

Description

Title of the invention: Electrical connection device comprising a busbar and at least one compressible element, released by melting of an MCP material to ensure an electrical connection of at least one accumulator of a battery module or battery pack. technical field

[0001] The present invention relates to the field of electrochemical accumulators, and more particularly to metal-ion accumulators.

[0002] The invention is mainly aimed at providing a solution for electrically connecting accumulators together within a module or battery pack, in a simple and autonomous manner, i.e. without the need for intervention by an operator and / or specific equipment.

[0003] Although described with reference to a Lithium-ion battery, the invention applies to any metal-ion electrochemical battery, i.e. also sodium-ion, Magnesium-ion, Aluminium-ion batteries...or more generally to any electrochemical battery or even to other electrochemistries such as nickel-cadmium.

[0004] A module or battery pack according to the invention can be on-board or stationary. For example, the fields of electric and hybrid transportation and grid-connected storage systems can be considered within the scope of the invention. Prior art

[0005] As schematically illustrated in figures 1 and 2, a lithium-ion battery or accumulator usually comprises at least one electrochemical cell consisting of an electrolyte constituent 1 between a positive electrode or cathode 2 and a negative electrode or anode 3, a current collector 4 connected to the cathode 2, a current collector 5 connected to the anode 3 and finally, a package 6 arranged to contain the electrochemical cell with sealing while being traversed by a part of the current collectors 4, 5.

[0006] The architecture of conventional lithium-ion batteries comprises an anode, a cathode, and an electrolyte. Several types of conventional architectural geometries are known:

[0007] - a cylindrical geometry as disclosed in the patent application US2006 / 0121348,

[0008] - a prismatic geometry as disclosed in US patents 7348098, US 7338733;

[0009] - a stacking geometry as disclosed in the patent applications US2008 / 060189, US 2008 / 0057392, and US patent 7335448.

[0010] The electrolyte component 1 may be in solid, liquid, or gel form. In the latter form, the component may include a polymer, ceramic, or microporous composite separator impregnated with organic or ionic liquid electrolyte(s) that allows the lithium ion to move from the cathode to the anode for charging and vice versa for discharging, thereby generating the current. The electrolyte is generally a mixture of organic solvents, for example, carbonates, to which a lithium salt, typically LiPF6, is added.

[0011] The positive electrode or cathode 2 is made of lithium cation insertion materials which are generally composite, such as LiFePO4, LiCoO2, LiNi0.33Mn0.33Co0.33O 2-

[0012] The negative electrode or anode 3 is very often made of graphite carbon or Li4TiO5Oi2 (titanate material), possibly also silicon-based or silicon-based composite.

[0013] The current collector 4 connected to the positive electrode is generally made of aluminum.

[0014] The current collector 5 connected to the negative electrode is generally made of copper, nickel-plated copper or aluminum.

[0015] A lithium-ion battery or accumulator can obviously comprise a plurality of electrochemical cells which are stacked one on top of the other.

[0016] Traditionally, a Li-ion battery or accumulator uses a pair of materials at the anode and cathode enabling it to operate at a high voltage level, typically equal to 3.6 Volts.

[0017] Depending on the type of application targeted, the aim is to produce either a thin and flexible lithium-ion battery or a rigid battery: the packaging is then either flexible or rigid and in the latter case constitutes a kind of casing.

[0018] Flexible packaging is usually made from a multilayer composite material, consisting of a stack of aluminum layers covered by one or more polymer film(s) laminated by bonding.

[0019] Rigid packaging is used when the applications are demanding where a long service life is required, for example with much higher pressures to withstand and a stricter level of sealing required, typically less than 10⁸ mbar.l / s, or in highly demanding environments such as the aeronautical or space sector.

[0020] Also, to date a rigid packaging used consists of a metal case, typically made of stainless steel (316L or 304 stainless steel) or aluminum (Al 1050 or Al 3003), or even titanium.

[0021] The geometry of most rigid Li-ion battery packaging cases is cylindrical, since most electrochemical cells in batteries are wound in a cylindrical shape around a cylindrical mandrel. Prismatic case shapes have also already been produced by winding around a prismatic mandrel.

[0022] One type of rigid cylindrical case, usually manufactured for a high-capacity Li-ion battery, is illustrated in [Fig.3].

[0023] A rigid prismatic-shaped case is also shown in [Fig.4].

[0024] The housing 6 comprises a cylindrical side casing 7, a base 8 with a at one end, a cover 9 at the other end, the base 8 and the cover 9 being assembled to the casing 7. The cover 9 supports the current output poles or terminals 4, 5. One of the output terminals (poles), for example the negative terminal 5 is welded to the cover 9 while the other output terminal, for example the positive terminal 4, passes through the cover 9 with interposition of a joint not shown which electrically isolates the positive terminal 4 from the cover.

[0025] The type of rigid housing widely manufactured also consists of a stamped cup and a lid, welded together around their periphery. In contrast, current collectors include a through-hole with a portion protruding from the top of the housing, forming a terminal also called the exposed battery pole.

[0026] A battery pack consists of a variable number of accumulators, which can reach several thousand, that are electrically connected in series or in parallel with each other and generally by mechanical and electrical connection bars or tracks, usually called busbars or clinquants depending on the embodiment and the desired current passage section.

[0027] Generally speaking, several electrical architectures can be defined within a battery pack P. Thus, batteries can be connected together in parallel, that is, with all the positive terminals connected together and all the negative terminals also connected together. These connections form a branch that can be connected in series to another branch. Alternatively, batteries can be connected together in series, that is, with the positive terminals connected to the negative terminals. These connections form a branch that can be connected in parallel to another branch.

[0028] Regardless of the architecture, each branch in series or parallel can generally include from two to dozens of accumulators.

[0029] The accumulators of current battery packs are generally assembled on one or more busbars by welding, screwing or shrink fitting.

[0030] An example of a battery pack P is shown in [Fig.5]. This pack consists of two identical Li-ion accumulator modules M1, M2 connected in series, each module M1, M2 consisting of four rows of accumulators connected in parallel, each row consisting of six Li-ion accumulators.

[0031] As shown, the mechanical and electrical connection between two Li-ion batteries in the same row is achieved by screwing on busbars B1, advantageously made of copper, each connecting a positive terminal 4 to a negative terminal 5. The connection between two rows of batteries in parallel within the same module M1 or M2 is ensured by a busbar B2, also advantageously made of copper. The connection between the two modules M1, M2 is ensured by a busbar B3, also advantageously made of copper.

[0032] Patent DE 102013021240 describes electrical connections between accumulators of a battery module made by laser welding.

[0033] CN209592106U describes electrical connections between accumulators of a module battery electrical connections made by wire by bridging welding, also called in Anglo-Saxon techniques of "wire bonding" or "ribbon bonding".

[0034] KR102321969B1 discloses electrical connections between accumulators made by screwed plates and helical compression springs. This solution requires complex manual assembly with a significant risk of short circuit.

[0035] All these traditional assemblies are relatively long with relatively high production costs, because they require the use of specific machines, and / or the proximity of at least one operator to manage the final assembly.

[0036] In addition, in general, live batteries which must be handled require operators to obtain restrictive authorizations, of the TST type (acronym for Live Working), with also the constraints of specific tooling and assembly range, while presenting significant electrical risks.

[0037] There is therefore a need for a solution that allows for simpler electrical connections between accumulators within a module or battery pack, which can be carried out autonomously, i.e. without the intervention of an operator and / or specific equipment.

[0038] The aim of the invention is to meet at least part of this need. Description of the invention

[0039] To this end, the invention relates, in one of its aspects, to an electrical connection device, intended to electrically connect at least one electrochemical accumulator, comprising:

[0040] - a busbar, one of whose faces comprises at least one connection surface electric,

[0041] - at least one mechanical guide piece adapted to guide the translationally busbar and thereby the connection surface in a direction (Z) along which the accumulator extends,

[0042] - at least one compressible element, arranged on the other face of the busbar,

[0043] - at least one block of phase change material (PCM) forming a spacer, whose change from solid to liquid state releases and brings the compressible element respectively from a compressed state to another state in which it is intended to bring the connection surface into contact with an output terminal of an accumulator.

[0044] In the context of the invention, a busbar is defined as a bar, blade, or plate made of electrically conductive material, optionally laminated with one or more electrically insulating materials, intended to electrically connect to an output terminal of at least one electrochemical cell to ensure electrical connection with another electrochemical cell in a battery pack or other electrical input / output element. Typically, a busbar according to the invention can be made of copper or aluminum, as required.

[0045] According to an advantageous embodiment, the busbar comprises two connection surfaces spaced apart, one of the connection surfaces being intended to be in contact with an output terminal of one accumulator, the other of the connection surfaces being intended to be in contact with an output terminal of another accumulator so as to electrically connect the two accumulators together. Thus, these two accumulators can be connected in series or in parallel.

[0046] According to an advantageous embodiment, at least one mechanical guide piece is adapted to guide the connection surface of the busbar in translation along a direction (Z) in which the accumulator extends. With such guidance along the axis of an output terminal of the accumulator to be connected, which is parallel to or coincides with the Z direction, the mechanical support of the connection surface on the output terminal is optimized, thereby improving the reliability of the electrical connection point.

[0047] According to an advantageous configuration, the connection surface is at least an outgrowth.

[0048] Preferably, this protrusion is conical in shape, the tip of which is intended to be in contact with an output terminal. A conical shape improves The reliability of the electrical connection is also affected because the conical tip can pierce the terminal.

[0049] According to an advantageous embodiment, the at least compressible element is a compression spring.

[0050] According to a first alternative, the compression spring is conical. A conical spring has the advantage of being compact once compressed.

[0051] According to a second alternative, the compression spring has coils formed by simultaneous winding and undulation. Such a compression spring also allows for high compactness along its compression axis (Z direction) while permitting greater support forces / loads. Such a compression spring may be the one marketed under the name "Multiwave".

[0052] According to another advantageous configuration, the spacer in the solid state is arranged around the guide piece.

[0053] Advantageously, the guide piece includes at least one groove opening to the outside, adapted to guide and localize the flow of the MCP material when it transitions to a liquid state. This groove or these grooves thus allow the MCP material in its liquid state to be evacuated to a suitable area within a module or battery pack.

[0054] The MCP material of the spacer is chosen from a synthetic wax or a petroleum wax, preferably a crystalline paraffin wax. Generally, the MCP material will be chosen according to the normal operating temperature, and therefore the electrochemistry of the cells in a module or battery pack for which a device according to the invention is intended. For Li-ion batteries, the maximum temperature during normal operation is typically around 60°C, while a temperature of around 100°C can lead to thermal runaway. Consequently, an MCP material with a melting point below 100°C is suitable for Li-ion batteries. A crystalline paraffin wax (or petroleum wax) spacer is a mixture of solid hydrocarbons that allows its melting point to be varied from 45 to 70°C.This temperature range allows the device according to the invention to be adapted to the specific needs of a Li-ion battery module or pack for a intended application (aeronautical, automotive, etc.). Alternatively, some polyolefin-based materials may also have a melting point below 100°C.

[0055] Advantageously, the mechanical guide part is made of electrically insulating material. This can be a self-lubricating dielectric plastic, such as polytetrafluoroethylene (PTFE) or other derivatives of polyoxymethylene (POM) or polyethylene terephthalate (PETP).

[0056] The invention also relates to a battery module (M) or battery pack, comprising:

[0057] - a plurality of electrochemical accumulators;

[0058] - at least one electrical connection device as described above, of which The MCP spacer material has previously changed from a solid to a liquid state, the protrusion being in contact with an output terminal of one of the accumulators to connect it with another of the accumulators or to form an output terminal of the module or battery pack.

[0059] According to an advantageous embodiment, where the device comprises two protrusions, one of the protrusions is in contact with an output terminal of one accumulator, the other of the protrusions is in contact with an output terminal of another accumulator so as to electrically connect the two accumulators together.

[0060] Preferably, at least one compressible element is supported against a wall forming part of a module or battery pack housing and / or a mounting plate for the module or battery pack. This facilitates the installation of the device(s). Furthermore, before the mechanical assembly of the module or battery pack, the device(s) according to the invention can be attached or integrated into a housing or mounting plate.

[0061] According to one embodiment, the MCP material spacer can be pre-positioned on an output terminal of a battery. This protects the upstream electrical potentials of the batteries and thus improves safety when handling the module. It also doubles the busbar's bearing surfaces in the initial configuration, i.e., before the MCP material is melted. Indeed, by placing a spacer on each of two output terminals to be electrically connected, the busbar initially rests on two surfaces that can be larger than the surface surrounding the guide piece.

[0062] For an application to a Li-ion module or battery pack, each accumulator being a Li-ion accumulator in which:

[0063] - the negative electrode material(s) is chosen from the group comprising the graphite, lithium, titanate oxide Li4TiO5O12;

[0064] - the positive electrode material(s) is chosen from the group comprising LiFePO4, LiCoO2, LiNiO.33MnO.33CoO.33Q2.

[0065] The invention also relates to a method for making a module or battery pack as described above, comprising the following steps:

[0066] i / implementation of the plurality of accumulators,

[0067] ii / implementation of at least one electrical connection device as described above, by placing at least one compressible element in a compressed state, the MCP spacer material being in the solid state,

[0068] iii / heating the plurality of the accumulators and at least one device, in particular in a furnace, so that the MCP spacer material passes from the solid state to the liquid state, and brings the compressible element to another state in which it makes contact the protrusion with an output terminal of an accumulator to connect it with another of the accumulators or to form an output terminal of the module or battery pack.

[0069] Thus, the invention essentially consists of an electrical connection device which integrates an electrical connection busbar with an outgrowth and which is mechanically guided to bring the outgrowth into contact with an output terminal of an electrochemical accumulator by the restoring force of a compressible element, released by the melting of an MCP material.

[0070] The MCP material in its solid form initially constitutes a spacer which allows the busbar to be electrically isolated and mechanically clamped in a remote position with respect to the output terminal to be electrically connected.

[0071] For the transition to the liquid state of the PCM spacer and thus to release the stress on the compressible element, preferably in the form of a spring, the module or battery pack which integrates a device, undergoes a heat treatment, in particular by passing through an oven which preferably operates at a low temperature, typically at about 50 to 60°C.

[0072] The invention can be implemented at the module level by establishing electrical connections between two battery terminals, but also at the battery pack level by interconnecting the battery pack modules via their respective output terminals. The overall power supply to the battery pack's electrical network can thus be fully automatic and secure.

[0073] In conclusion, the invention offers numerous advantages, including: - an electrical connection solution with simple and reliable kinematics, - a fully autonomous electrical connection solution, that is to say- to say without the need for operator intervention or the implementation of specific equipment (fusion of spacers in MCP material), - the realization of an assembly of a battery module or battery pack without regulatory constraints for live working (TST), - Safety during the establishment of electrical connections for a module or battery pack, as power-up is secure and fully automatic, - the possibility of easy and quick disassembly of a module or battery pack, without being destructive, - easy integration into a housing or mounting plate or into an electronic board of a module or battery pack. - the simplification of the transport of a module or battery pack, without electrical power, before its implementation, i.e. the realization of its electrical connections by a simple heat treatment, in particular in an oven, in order to be able to function in its final application.

[0074] Other advantages and features of the invention will become clearer from the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures. Brief description of the drawings

[0075] [Fig-1] [Fig.1] is a schematic exploded perspective view showing the different components of a lithium-ion battery.

[0076] [Fig.2] [Fig.2] is a front view showing a lithium-ion battery with its flexible packaging according to the state of the art.

[0077] [Fig. 3] [Fig. 3] is a perspective view of a lithium-ion battery according to state of the art with its rigid packaging consisting of a cylindrical case.

[0078] [Fig.4] [Fig.4] is a perspective view of a lithium-ion battery according to state of the art with its rigid packaging consisting of a prismatically shaped case.

[0079] [Fig. 5] [Fig. 5] is a perspective view of an assembly using busbars state-of-the-art lithium-ion accumulators, forming a battery pack.

[0080] [Fig. 6] [Fig. 6] is a perspective view of an electrical connection device according to the invention before its implementation in a battery module or battery pack.

[0081] [Fig.7] [Fig.7] is a perspective view of a mechanical guide part of the device according to [Fig.6].

[0082] [Fig.8] [Fig.8] reproduces [Fig.7] with the installation of the material spacer MCP on the guide piece.

[0083] [Fig.9] [Fig.9] is another perspective view of the device in [Fig.6], without the presence of compression springs.

[0084] [Fig. 10] [Fig. 10] shows in perspective a first alternative embodiment of a compression spring of a device according to the invention, in a conical shape.

[0085] [Fig. 11 A], [Fig. 1 IB] Figures 11A and 1 IB show in side view an electrical connection device according to the invention opposite two output terminals of two adjacent accumulators, respectively before and after the connection has been made by melting the MCP material of the device.

[0086] [Fig. 12] [Fig. 12] is a perspective view of a variant of a mechanical guide part of a device according to the invention

[0087] [Fig. 13] [Fig. 13] schematically shows the evacuation of the MCP material during melting, as obtained by the part according to [Fig. 12].

[0088] [Fig. 14] [Fig. 14] is a perspective and transparency view of a battery module with prismatic accumulators electrically connected to each other by a plurality of devices according to the invention.

[0089] [Fig. 15] [Fig. 15] shows a variant arrangement of MCP material spacers of a device according to the invention.

[0090] [Fig.10A], [Fig.10B] Figures 16A and 16B show in side view an electrical connection device according to [Fig. 15], opposite two output terminals of two adjacent accumulators, respectively before and after the connection has been made by melting the MCP material of the device.

[0091] [Fig. 17] [Fig. 17] shows in perspective a second alternative embodiment of a compression spring of a device according to the invention. Detailed description

[0092] Figures 1 to 5 relate to different examples of Li-ion accumulators, flexible packaging and accumulator cases, as well as a battery pack according to the state of the art.

[0093] Figures 1 to 5 have already been discussed in the preamble and are therefore not discussed further below.

[0094] For the sake of clarity, the same references designating the same elements according to the prior art and according to the invention are used for all figures 1 to 17.

[0095] In the application as a whole, a battery module is a plurality of accumulators, defined in a position with respect to an orthogonal XYZ frame constituting a trihedron, comprising three axes perpendicular in pairs, namely:

[0096] - an X-axis, defining a transverse direction,

[0097] - a Y-axis, defining a transverse direction, which together with the X-axis defines a plane XY,

[0098] - a Z-axis, defining a longitudinal direction, perpendicular to the XY plane, and defining the general direction in which the accumulators extend, that is to say the main direction of the accumulators in the sense in which their external electrical contacts are accessible.

[0099] Throughout this application, the terms "lower", "upper", "bottom", "top", "below" and "above" are to be understood by reference to vertically arranged Li-ion battery cases.

[0100] Figures 6 to 10 show an example of an electrical connection device 10 according to the invention and its components.

[0101] This device 10, intended for electrically connecting at least one electrochemical accumulator, comprises firstly a busbar 11, one face of which has two electrical connection protrusions 110 spaced apart. In the illustrated example, each of these protrusions 110 is conical in shape, the tip of which is intended to be in contact with an output terminal of an accumulator. The electrically conductive busbar 11 is typically made of aluminum or copper. Alternatively, the busbar may have only one or more conductive bearing surfaces, or connection surfaces, intended to form electrical contact, without these necessarily being in the form of protrusions. These connection surfaces may therefore be flat, recessed, or protruding from the busbar.A non-planar contact, for example in the form of a hollow or, even more preferably, a protrusion, remains preferable in order to localize the support force and thus improve the quality of the electrical contact.

[0102] A mechanical guide piece 12 allows the busbar 11, and thereby the protrusions 110, to be guided in translation in a direction (Z) along which the accumulator extends. In the example illustrated in [Fig. 7], the piece 12 consists of a tenon 120 extending from a base 121 to position the busbar 11 in a module or battery pack and thus guide it. The piece 12 also includes one or more grooves 122 formed in its base 121, the function of which will be explained below.

[0103] Preferably, as shown, the mechanical guide piece 12 is arranged in the center of the busbar 11 and the two protrusions 110 are arranged symmetrically on either side of this piece 12.

[0104] Preferably also, to electrically isolate the busbar 11, part 12 is made of electrically insulating material.

[0105] A phase change material (PCM) block forming a spacer 13 is arranged around the tenon 120 of the guide piece 12. The PCM material of the spacer can be a crystalline type paraffin wax.

[0106] Two compression springs 14 are arranged on the face of the busbar 11 opposite that of the protrusions 110. Preferably, each spring 14 is centered opposite a protrusion 110. The two springs 14 are preferably identical.

[0107] As illustrated in [Fig.10], a compression spring 14 can be conical.

[0108] Figures 1 IA and 1 IB show the electrical connection between a positive output terminal 4 of a accumulator Al and a negative output terminal 5 of an accumulator A2.

[0109] As can be seen in [Fig. 11 A], the springs 14 are initially pre-stressed against a wall 20 which may be a retaining plate for a battery module and the spacer 13 keeps each of the protrusions 110 away from one of the terminals 4 or 5 of the Al, A2 accumulators.

[0110] A change from solid to liquid state by melting of the MCP material of the spacer 13, releases and brings each spring 14 into another compressed state.

[0111] As seen in [Fig. 1 IB], each of the springs 14 thus released exerts a force which brings an outgrowth 110 into contact with an output terminal 4 or 5 of the accumulator respectively Al or A2.

[0112] As illustrated in Figures 12 and 13, the groove(s) 122 formed in the base 121 and opening to the outside allow the flow of material C to be guided and localized during its transition to a liquid state. This allows the liquid to be evacuated to an area of ​​a module or battery pack where the material can resolidify safely and without the need for collection.

[0113] The [Fig.14] illustrates a prismatic Li-ion, Al, A2,...,A6 accumulator module M in electrical series, in which all the electrical connections are made by devices 10.1 to 10.5 which have just been described.

[0114] More specifically, this module M comprises two retaining plates 20, 21 between which the Al to A6 accumulators are held. The plates 20, 21 are fixed to each other by means of mechanical tie rods 22 in the form of bolts.

[0115] Each 120 tenon is fixed to the upper retaining plate.

[0116] Once the MCP material of the initial spacers 13 of the devices 10.1 to 10.5 has changed from its solid state to its liquid state, one of their two protrusions 110 is in contact with a positive output terminal 4 of one of the accumulators and the other of their protrusions 110 is in contact with a negative output terminal 5 of an adjacent accumulator, which achieves their electrical series connection.

[0117] In the illustrated example, the output terminals 23, 24 of the module M can be made by two busbars 11, one of which is directly soldered to a positive output terminal 4 of an accumulator Al and the other is directly soldered to a negative output terminal 5 of an accumulator A6.

[0118] The process for making such an M module is now described.

[0119] Step i / : the plurality of Al to A6 accumulators are first placed on the lower retaining plate 21.

[0120] Step ii / : the upper plate 20 is put in place which supports all the electrical connection devices 10.1 to 10.6, all the springs 14 being pre-stressed against the upper retaining plate 20. The MCP material of the spacers 13 being in the solid state, all the protrusions 110 are at a distance from the output terminals 4, 5 and therefore no electrical connection is made between the accumulators Al to A6.

[0121] Then the mechanical assembly is carried out using the retaining plates 20, 21 and the mechanical tie rods 22.

[0122] The electrical connection process within the module M is then carried out according to the following step iü / .

[0123] Step iii / the module M, placed in a furnace, undergoes heating to a temperature above the melting temperature of the MCP material of the spacers 13. The heating is carried out for a sufficient time to completely disappear the spacers 13.

[0124] In this way, the springs 14 are released until each of the busbars 11 is brought against the base 121 of a part 12. In this abutment position, one protrusion 110 of one of the devices 10.1 to 10.5 is in contact with a positive output terminal 4 of a battery, while the other of the two protrusions 110 is in contact with an adjacent battery. The batteries A1 to A6 are therefore all electrically connected in series with each other.

[0125] Fig. 15 illustrates a variant where a spacer made of MCP material 13 can be arranged not around a guide piece 12 but directly on a positive terminal 4 or negative terminal 5 of an accumulator Al or A2 respectively.

[0126] Figures 16A and 16B illustrate the configurations before and after fusion of the spacers 13 according to this variant of [Fig. 15]. As shown in [Fig. 16A], it is advantageous to provide that a spacer 13 includes a preferably central housing in which a projection 110 is initially housed. Thus, in this variant, the points 110, by virtue of their conical shape, push the wax outwards before coming into contact with the outlet terminals of the accumulators. To better evacuate the wax, it is also possible to provide the periphery of one and / or the other of the outlet terminals with one or more drainage channels.

[0127] Figure 17 shows an alternative embodiment of a compression spring 14 for a device 10 according to the invention. This compression spring 14 has coils formed by simultaneous winding and corrugation and is marketed under the name "Multiwave".

[0128] The invention is not limited to the examples just described; in particular, features of the illustrated examples can be combined in unillustrated variants.

[0129] Other variants and improvements may be envisaged without departing from the scope of the invention.

[0130] In the illustrated examples, the A1-A6 batteries shown have prismatic case 6s. The invention can of course be implemented for any other battery format, in particular cylindrical, typically in sizes 18650, 21700, 26650, 4680.

[0131] A device of the invention 10 can be implemented with a single protrusion 110 to connect an output terminal of a complete module or to connect it to another module within the same battery pack.

[0132] The positive output terminals 4 and negative output terminals 5 of the accumulators within a module M can be connected together, in order to electrically connect the different accumulators in series and / or parallel in groups.

[0133] The positive output terminals 23 and negative output terminals 24 of a module can be made by means of a device 10 according to the invention.

[0134] Modules M can also be electrically connected to each other by means of one or more devices 10 according to the invention.

Claims

Demands

1. Electrical connection device (10), intended to electrically connect at least one electrochemical accumulator, comprising: - a busbar (11), one face of which includes at least one electrical connection surface (110), - at least one mechanical guide piece (12) adapted to guide the busbar and thereby the connection surface in translation in a direction (Z) along which the accumulator extends, - at least one compressible element (14), arranged on the other face of the busbar, - at least one block of phase change material (PCM) forming a spacer (13), the change of which from solid to liquid state releases and brings the compressible element respectively from a compressed state to another state in which it is intended to bring the connection surface into contact with an output terminal of an accumulator.

2. Device (10) according to claim 1, the busbar comprising two connection surfaces spaced apart from each other, one of the connection surfaces being intended to be in contact with an output terminal of one accumulator, the other of the connection surfaces being intended to be in contact with an output terminal of another accumulator so as to electrically connect the two accumulators together.

3. Device according to claim 1 or 2, at least one mechanical guide piece being adapted to guide in translation the connection surface of the busbar in a direction (Z) along which the accumulator extends.

4. Device according to any one of the preceding claims, at least one connection surface being an outgrowth.

5. Device according to claim 4, the protrusion being conical in shape, the tip of which is intended to be in contact with an output terminal.

6. Device according to any one of the preceding claims, the at least compressible element being a compression spring.

7. Device according to claim 6, the compression spring being conical or coiled by simultaneous winding and undulation.

8. Device according to any one of the preceding claims, the spacer in the solid state being arranged around the guide piece.

9. Device according to claim 8, the mechanical guide part comprising at least one groove opening to the outside, adapted to guide and locate the flow of the MCP material when passing into the liquid state.

10. Device according to any one of the preceding claims, the MCP material of the spacer being selected from a synthetic wax or a petroleum wax, preferably a crystalline type paraffin wax.

11. Device according to any one of the preceding claims, the mechanical guide part being made of electrically insulating material.

12. Battery module (M) or battery pack, comprising: - a plurality of electrochemical accumulators (Al, A2...A6), - at least one electrical connection device (10.1, 10.2, ...10.5) according to any one of the preceding claims, the spacer MCP material of which has previously changed from the solid state to the liquid state, the connection surface being in contact with an output terminal of one of the accumulators to connect it with another of the accumulators or to form an output terminal of the module or battery pack.

13. Module or battery pack according to claim 12, the device being according to any one of claims 2 to 11, one of the connection surfaces being in contact with an output terminal of one accumulator, the other of the connection surfaces being in contact with an output terminal of another accumulator so as to electrically connect the two accumulators together.

14. Module or battery pack according to claim 12 or 13, at least one compressible element being supported against a wall forming part of a housing of the module or battery pack and / or of a retaining plate of the module or battery pack.

15. Module or battery pack according to any one of the preceding claims, each accumulator being a Li-ion accumulator in which: - the negative electrode material(s) is selected from the group comprising graphite, lithium, titanate oxide Li4TiO5Oi2; the positive electrode material(s) is selected from the group comprising LiFePO4, LiCoO2, LiNi0.33Mn0.33Co0.33O2.

16. A method for producing a module or battery pack according to any one of claims 12 to 15, comprising the following steps: i / placing the plurality of accumulators, ii / placing at least one electrical connection device according to any one of claims 1 to 11, by putting the at least one compressible element into a compressed state, the MCP spacer material being in the solid state, iü / heating the plurality of accumulators and the at least one device, in particular in a furnace, so that the MCP spacer material passes from the solid state to the liquid state, and brings the compressible element into another state in which it makes contact the connection surface with an output terminal of an accumulator to connect it with another of the accumulators or to form an output terminal of the module or battery pack.

Images