Protective cover to protect a battery module terminal

Abstract

Protective cover (8) for protecting a terminal (7) of a battery module (9), the terminal comprising a threaded hole (6), the protective cover comprising at least one nail (1) with a rod (5) extending along a rod axis and capable of being introduced into the threaded hole, and a cover (2) capable of covering the terminal, characterized in that the protective cover is made of at least two separate pieces, or three separate pieces, each being obtained by an additive manufacturing process, in particular by 3D printing, from a compostable bioplastic material, such as polylactic acid. Abstract figure: Fig. 3

Description

Title of the invention: Protective cover for protecting a battery module terminal

[0001] The present invention relates to a protective cover for protecting a battery module terminal.

[0002] A battery module for an electric vehicle or hybrid vehicle contains a significant amount of electrical energy. The traction battery corresponds to a set of modules connected together in series. The voltage across the battery terminals is high, often 400 volts. The voltage across a module can range, for example, from 20 volts to 50 volts.

[0003] In a nominal use situation in a vehicle, the modules are electrically connected to each other by conductive elements called bus bars, and are mechanically protected inside a housing called a battery pack.

[0004] In certain situations in the life of the vehicle, it may be necessary to intervene on the battery modules, and to electrically disconnect the modules from their neighbors. This may be a phase of repair of the vehicle. It may also be a removal at the end of the battery's life.

[0005] When these operations are carried out, the battery modules are electrically charged, and a possible short-circuiting of the terminals of a module can lead to undesirable phenomena such as sparks, very significant heating, or even an explosive incident.

[0006] According to certain repair or end-of-life procedures, it is planned to install a piece of insulating tape on each terminal. It turns out that in practice the installation of this piece of tape is not always done correctly.

[0007] The inventors sought to improve the situation, in particular to propose a more reliable solution for isolating the electrical terminals of a module.

[0008] For this purpose, a protective cover is proposed for protecting a battery module terminal, the terminal comprising a threaded hole, the protective cover comprising at least one nail with a rod extending along a rod axis and capable of being introduced into the hole, the protective cover comprising at least one nail with a rod extending along a rod axis, and a cover capable of covering the terminal, characterized in that the cover comprises an orifice allowing the passage of the rod of the nail through said cover and the nail comprises a nail head of larger dimension than the orifice, the rod of the nail being capable of passing through the cover via said orifice until the nail head abuts against the cover, so as to house the rod of the nail in the hole of the terminal.

[0009] Thanks to these provisions, once the protective cover is installed on the terminal, the cover completely covers the electrical terminal, and no foreign element, metallic or otherwise, can come into contact with the electrical terminal. As a result, the risk of short circuits is eliminated.

[0010] Clever use is made of the existence of the hole of interest, usually used to ensure the electrical connection, but used here to receive the nail and secure the cover and its covering function preventing access to any live part of the battery module terminal.

[0011] Driving the nail into the hole thus causes the cover to be fixed to the electrical terminal of the module.

[0012] According to one embodiment, the nail and the cover are produced as at least two separate parts, each obtained by an additive manufacturing process, e.g. by 3D printing, from a compostable bioplastic material, such as polylactic acid.

[0013] 3D printing or additive manufacturing brings together manufacturing processes that allow the creation of volume parts by adding material in successive layers, generally in successive horizontal planes relative to a starting base plane.

[0014] Advantageously, the two parts, i.e. the nail and the cover (without excluding a third) can be obtained quickly using a 3D printer, from a material that is very readily available for 3D printing.

[0015] The said material is very cheap and is also bio-compostable. For example, one can opt for a polylactic acid obtained from corn starch.

[0016] We also notice that 3D printers have become very common.

[0017] Advantageously, the two or three parts produced by 3D printing are small in size and can be produced by all known 3D printers, even basic domestic printers.

[0018] In fact, each of the two or three pieces preferably fits into a cube with sides of 40 millimeters.

[0019] Advantageously, no mold is necessary to manufacture the parts of the protective cover.

[0020] It is noted that the term “compostable bioplastic material” encompasses materials which may be a biosourced and non-biodegradable but compostable material, a biosourced and biodegradable material, or a material derived from fossil resources and nevertheless biodegradable.

[0021] According to one embodiment, the protective cover is made of three separate pieces, namely the nail, the cover and furthermore a button, the protective cover being formed as an assembly comprising the nail, the button and the cover assembled as a subassembly.

[0022] Advantageously, the button facilitates the insertion of the nail into the hole using a finger of the user / operator. The button is made integral with the nail. The button can be pressed via a surface of at least one square centimeter, and the pressing force is transmitted to the nail which has a smaller cross-section. Driving the nail is thus easy and ergonomic.

[0023] According to an alternative formulation, the protective cover comprises, in addition to the nail and the cap, a button, and the head of the nail is capable of being slid into a groove of the button in a groove direction perpendicular to the rod axis.

[0024] The three parts can be assembled as a prepared subassembly before installation on the battery module terminal.

[0025] The button assembled on the nail with the rod together thus constitute a mushroom-shaped piece.

[0026] According to one embodiment, the button is obtained by an additive manufacturing process, from a compostable bioplastic material, such as polylactic acid.

[0027] Thus, the three pieces each have a very simple design and can be produced by 3D printing using very simple geometric definition files.

[0028] It should be noted that the presence of the button is not mandatory. Note that the nail can be inserted without the presence of a button. A conventional tool can be used to drive the nail.

[0029] According to one embodiment, the rod has a generally rectangular, or even square, section. There are thus four lines of contact between the rod and the inner wall of the hole, and in particular the thread of the hole when the hole is threaded. In addition, the orientation of the nail rod around the rod axis can be arbitrary in the cylindrical hole.

[0030] According to a particular embodiment, the orifice is of square or rectangular section. The section of the rod is inscribed inside the section of the orifice. In this case the rod of the nail will be indexed around the rod axis.

[0031] According to one embodiment, the rod has two branches separated by a gap and joined together by a distal portion of domed shape.

[0032] The rod thus has an elasticity which makes it possible to bring the branches together and reduce the gap. This elasticity allows for insertion with moderate force into the threaded hole and leaves a residual stress which ensures positive retention of the nail and the protective cover relative to the terminal.

[0033] According to one embodiment, the cover comprises a flat main plate intended to be pressed against an upper flat face of the terminal, and a skirt extending perpendicular to the main plate. The skirt extends downwards.

[0034] The skirt protects the terminal from the insertion of a foreign body from the vertical face of the battery module.

[0035] According to one embodiment, the hood comprises a rising wall extending perpendicularly directly to the main plate, a step extending perpendicular to the rising wall, and a lateral reinforcement connecting an edge of the main plate and an edge of the rising wall, the lateral reinforcement serving as a base in the additive manufacturing process.

[0036] The rising wall extends upwards and the step is designed to cover the upper face of the battery module. The cover thus has a complete enveloping effect with respect to the terminal and its immediate surroundings.

[0037] The invention also relates to a battery module suitable for equipping an electric or hybrid vehicle, comprising a positive terminal, the positive terminal being protected by a first protective cover as described previously, and a negative terminal, the negative terminal being protected by a second protective cover as described previously, the nail shank of each protective cover being inserted into the respective hole of each terminal.

[0038] According to one embodiment, the nail rod of each protective cover is mounted with constraint in the corresponding hole, which is threaded.

[0039] According to one embodiment, the first and second protective covers are differentiated on the one hand by the relative position of the orifice with respect to the main plate, and on the other hand by the marking, positive or negative, that they carry. Given that the parts are produced by 3D printing, such diversity is not at all a problem. Indeed, there is no molding mold to be provided. Two separate definition files are simply used for 3D printing.

[0040] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] illustrates schematically in perspective a part of a battery module, at the location of which the positive and negative terminals are arranged, with the protective covers installed, the nail of the negative terminal being omitted - [Fig.2] schematically illustrates in front view the battery module from the side electrical terminals; - [Fig.3] shows in sectional view the area of ​​a battery terminal with an example generic protective cover installed on the electrical terminal; - [Fig.4] illustrates an example of a hood in elevation view in its front position 3D printing bricks; - [Fig.5] illustrates in perspective an example of a nail; - [Fig.6] illustrates in section view the nail shank, according to section line VI visible in [Fig.5]; - [Fig.7] illustrates a top view of an example of a button; - [Fig.8] illustrates in front view the example button of [Fig.7]; - [Fig.9] illustrates in perspective an example of a subassembly comprising a hood a nail and a rod; - [Fig. 10] is similar to [Fig.4] and illustrates a variant of the hood for the negative terminal; - [Fig.l 1] shows a snapshot illustrating the fingers of a hand of an operator who is preparing to insert a protective cover according to the present invention onto the terminal of the battery module.

[0041] In the various figures, the same references designate identical or similar elements. For reasons of clarity of the description, certain elements are not necessarily represented to scale.

[0042] In Figures 1 to 3, a battery module 9 appears. In the present context, this is a battery module of a battery pack for an electric or hybrid vehicle.

[0043] The battery module 9 has a generally parallelepiped shape. The battery module has a width L9 of between 10 cm and 40 cm in practice, depending on the application. The battery module has a height H9 of between 15 cm and 25 cm in practice. The third dimension is also significant, e.g. several tens of centimeters.

[0044] By convention, a spatial geometric reference is defined which comprises a first direction X along the width of the module, a second direction Y along the length of the module and a third direction Z, in length, along the height of the module. It is noted that this reference coincides with the reference usually used for the vehicle when the length direction of the batteries is in the transverse direction of the floor of the vehicle.

[0045] The electrical interfaces of the battery module are located in a region of an upper edge of the parallelepiped. The positive power terminal 71 is distant from the negative power terminal 72. Each of the electrical terminals is located in a recess relative to the general parallelepiped envelope. Between the positive power terminal 71 and the negative power terminal 72, there is a signal connector 91, also protected in a specific median recess.

[0046] The battery module 9 includes fixing wells 92 in the four corners.

[0047] Each of the electrical terminals is a metal part surrounded on four sides by plastic walls 90, only the upper wall is flush and protrudes slightly as illustrated in [Fig.2].

[0048] Each of the electrical terminals comprises a bore, i.e. here a threaded hole 6, which is used for electrical connection, by means of inserting and tightening a screw in the threaded hole 6.

[0049] According to the example illustrated, the diameter of the hole 6 and its thread conform to a common mechanical standard of the trade and are of size M6.

[0050] On the upper face 94 of the module, markings are provided to identify the respective polarity '+' and of each electrical terminal.

[0051] Apart from the marking and the relative position of the threaded hole, the two terminals 71,72 are mechanically similar and are collectively identified by the reference 7.

[0052] In [Fig. 1], a protective cover 81 proposed by the present invention is shown on the positive terminal, and on the negative terminal only the cover 82 forming part of the protective cover is shown.

[0053] In [Fig.2], the main plate 20 of the cover is shown on the negative terminal in section as will be seen in detail later.

[0054] According to the present invention, the protective cover generally noted 8 comprises on the one hand a nail 1 with a rod 5, and a cover 2.

[0055] The cover 2 is capable of covering the terminal 7 as will be seen in detail below.

[0056] The nail 1 comprises the rod 5 and a nail head 4. The nail head 4 is substantially a prismatic bar with a length D2 and a thickness el.

[0057] The rod 5 extends along an axis called here rod axis A. The rod 5 is capable of being introduced into the threaded hole 6 of the terminal 7. It is noted that the insertion is done without screwing, according to a simple translation along the rod axis A.

[0058] As seen in Figures 5 and 6, the rod has a generally rectangular section which can be received in the hollow cylindrical space of the threaded hole.

[0059] The rod has two branches 11, 12 each extending along the rod axis A. The two branches 11, 12 are separated by a gap 14. The two branches 11, 12 are joined together by a distal portion 13 of domed shape.

[0060] The distal part 13, namely the front part in the insertion movement, is curved or even conical to form a swallow effect in cooperation with the flared entry chamfer 61, this being conducive to easy insertion without precise positioning in the ZA axis of the threaded hole (see [Fig.3]).

[0061] In addition, ridges or gadroons 15 are provided on the outer flank of the two branches. The ridges 15 are in the form of an arc centered on A or rectilinear.

[0062] The respective outer faces of the two branches are separated by a distance Dl, excluding the beads.

[0063] As can be seen in [Fig.6], the dimension D1 at rest slightly exceeds the internal diameter of the thread. So that during the insertion movement, the two branches 11, 12 come together, against an intrinsic elastic return linked to their shape at rest. The beads 15 are anchored in the internal thread of the threaded hole 6. A residual radial stress remains, ensuring positive support.

[0064] Note that hole 6 is not necessarily threaded.

[0065] Optionally, the protective cover 8 may further comprise a button 3 provided to facilitate the driving of the nail into the threaded hole, in which case the protective cover 8 is formed of three separate pieces.

[0066] As seen in Figures 7 and 8, the button 3 is presented as a disc with a flat face on one side and on the other side the presence of a groove 31.

[0067] The button 3 comprises a discoid body 30, with a thickness for example of 2 to 3 mm. The diameter of the discoid body can be for example chosen between 1 cm and 2 cm. On the side opposite the flat face 35, a groove 31 is provided extending along a groove axis B. In the example illustrated, it is a blind groove, the mouth being provided with an entry chamfer 32.

[0068] The nail head 4 is introduced by translation along the axis B from the mouth until it contacts the longitudinal end of the groove. A slight tightening of the width dimension may be provided, so that the insertion allows the button to be held naturally on the nail.

[0069] The cover 2 comprises a flat main plate 20 and a skirt 24. The skirt 24 extends perpendicularly to the main plate downwards.

[0070] The main flat plate 20 is intended to be pressed against an upper plane 70 of the terminal 7 (see [Fig.2], right side).

[0071] Furthermore, in the illustrated example, the cover 2 comprises a rising wall 21 extending upwards perpendicular to the main plate 20. A step 22 extending perpendicular to the rising wall is optionally provided. Furthermore, the cover 2 comprises a lateral reinforcement 26 connecting an edge of the main plate 20 and an edge of the rising wall 21.

[0072] The cover 2 has main dimensions, L1 and L2, typically between 2 cm and 4 cm.

[0073] As illustrated in [Fig.4], the lateral reinforcement 26 serves as a base in the additive manufacturing process. According to one embodiment, the lateral reinforcement 26 is triangular in shape.

[0074] In the X2 Y2 Z2 reference frame of [Fig.4], the X2Y2 plane represents the base plane of the 3D printer and the Z2 direction represents the additive manufacturing elevation.

[0075] The first layers of solidification of the material include the lateral reinforcement and provide stability to the part being formed.

[0076] There is provided on the main plate 20 an orifice 25 forming a passage to allow the nail shank to pass through. The orifice 25 has a rectangular section in the example illustrated. As seen in [Fig.6], the dimensions of this orifice are slightly greater than the section of the shank 5 of the nail 1, but the length of the bar of the nail head is greater than the available space provided by this orifice 25 to prevent the nail head from passing through the orifice.

[0077] It should be noted that the hood could be simpler, without the aforementioned step.

[0078] The compostable bioplastic material from which the cap, nail and button are manufactured by 3D printing includes materials which may be a bio-sourced and non-biodegradable but compostable polymer material, a bio-sourced and biodegradable polymer material, or a polymer material derived from fossil resources and nevertheless biodegradable.

[0079] In [Fig. 10], we see the cover provided for the negative terminal which differs from the cover provided for the positive terminal by the location of the hole forming the passage for the nail as well as the marking '-'. The rest of the characteristics are identical apart from the position of the triangular reinforcement where applicable.

[0080] Regarding the manufacturing of the nail, [Fig.5] indicates that the plane of the directions XI Y1 forms the base of the 3D printer; the elevation ZI corresponding to the thickness el. Additive manufacturing is very simple because the profile in the base plane is raised identically to itself.

[0081] Concerning the manufacture of button 3, it is conventionally manufactured flat on its back 35.

[0082] As illustrated in [Fig.9], it is intended that the protective cover 8 be assembled as a sub-assembly before being inserted into the threaded hole 6 of the terminal 7.

[0083] It is noted that it is required to use protective gloves G to operate the elements which may be under high voltages in order to prevent any electric shock. The protective cover as proposed is advantageously compatible with operation with gloved hands, in particular with the presence of the button 3.

[0084] To remove the protective cover 8, there are several possibilities. Either the nail is removed by grasping the button or even the nail head by hand. A tool such as pliers can also be used to remove the nail. Alternatively, a thin object can be slid under the protective cover above the plastic cover 90 which surrounds the terminal on a side where the skirt is not present; by levering, the entire protective cover is extracted upwards.

[0085] The protective cover 8 can be reused later for the same function. The protective cover can also be placed in a trash can. It either decomposes slowly over time or it decomposes in a compost environment. In any case, due to the nature of its constituent material, the protective cover does not present any environmental hazard.

Claims

Claims

1. Protective cover (8,81,82) for protecting a terminal (7) of a battery module (9), the terminal comprising a hole (6), the protective cover comprising at least one nail (1) with a rod (5) extending along a rod axis (A), and a cover (2) capable of covering the terminal, characterized in that the cover comprises an orifice (25) allowing the passage of the rod of the nail through said cover and the nail comprises a nail head (4) of larger dimension than the orifice, the rod of the nail being capable of passing through the cover via said orifice until the nail head comes into abutment against the cover, so as to house the rod of the nail in the hole of the terminal.

2. Protective cover according to claim 1, characterized in that the nail (1) and the cover (2) are produced as at least two separate parts, each obtained by an additive manufacturing process, eg by 3D printing, from a compostable bioplastic material, such as polylactic acid.

3. A protective cover according to claim 1, further comprising a button (3), and wherein the head of the nail (4) is capable of being slid into a groove (31) of the button in a groove direction (B) perpendicular to the rod axis (A).

4. Protective cover according to claim 3, characterized in that the button is obtained by an additive manufacturing process, from a compostable bioplastic material, such as polylactic acid.

5. Protective cover according to any one of claims 1 to 4, in which the rod (5) has a rectangular section.

6. Protective cover according to any one of claims 1 to 5, in which the rod has two branches (11, 12) separated by a gap (14) and joined together by a distal part (13) of domed shape.

7. Protective cover according to any one of claims 1 to 6, in which the cover (2) comprises a flat main plate (20) intended to be pressed against an upper plane of the terminal, and a skirt (24) extending perpendicular to the main plate.

8. A protective cover according to claim 2 and claim 7, wherein the cover (2) comprises a rising wall (21) extending perpendicular to the main plate (20), a step (22) extending perpendicular to the rising wall, and a lateral reinforcement (26) connecting an edge of the main plate and an edge of the rising wall, the lateral reinforcement (26) serving as a base in the additive manufacturing process.

9. Battery module (9) suitable for equipping an electric or hybrid vehicle, comprising a positive terminal, the positive terminal being protected by a first protective cover (81) according to any one of claims 1 to 8, and a negative terminal, the negative terminal being protected by a second protective cover (82) according to any one of claims 1 to 8, the shank (5) of the nail (1) of each protective cover being inserted into the respective hole (6) of each terminal (7).

10. A battery module (9) according to claim 9, wherein the nail rod (5) of each protective cover is constrainedly mounted in the corresponding hole (6), which is threaded.

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