Electrical battery connecting equipment

Abstract

Apparatus for connecting electric batteries, comprising: at least one first electrical conductor provided with at least one substantially planar first face; at least one second electrical conductor provided with at least one substantially planar second face facing said first face; said first conductor and said second conductor defining between said first face and said second face a housing volume configured to accommodate at least one battery extending transversely between said first conductor with a first pole and said second conductor with a second pole; characterized by comprising resiliently yielding connecting means provided on said first face of said first electrical conductor and / or on said second face of said second electrical conductor and configured to be interposed between said first face and said first pole (Pl) and / or said second face and said second pole; said connecting means exhibiting a decreasing nonlinear elastic modulus to ensure a substantially constant pushing force on said battery against said conductors.

Description

[0001] ELECTRICAL BATTERY CONNECTING EQUIPMENT

[0002] DESCRIPTION

[0003] FIELD OF THE TECHNIQUE

[0004] The present invention relates to apparatus for connecting electric batteries, i.e., apparatus configured to house, hold, and electrically connect at least one electric battery, particularly of a substantially cylindrical shape. The discussed apparatus finds advantageous use in the production and commercialization field of devices for storing electrical energy. Therefore, the electric battery connecting apparatus in question is employed in any technical field that utilizes electric batteries, such as the electric vehicle production field.

[0005] STATE OF THE ART

[0006] In the technical field of producing and commercializing devices for storing electrical energy, and particularly in the field of producing and commercializing apparatus for connecting electric batteries, especially of a substantially cylindrical shape, the longstanding problem is known of securely connecting cylindrical batteries, ensuring mechanical strength and proper mechanical connection. It is known in the relevant technical field to connect cylindrical batteries to an electrical conductor by welding.

[0007] More specifically, with particular reference to the attached figure 1, which illustrates a known type of apparatus, known are pieces of apparatus A for connecting electric batteries B, comprising pairs of substantially planar electrical conductors C, opposed and parallel to each other, between which battery cells, usually cylindrical, are arranged transversely. The battery cells are arranged parallel to each other and are electrically and mechanically connected at their ends to the respective conductors. Typically, such apparatus is designed for various applications, particularly for electric or hybrid vehicles. Obviously, in such an application, there is a need for the batteries to be mechanically connected in a secure and safe manner to prevent the risk of batteries detaching from the conductors, compromising the operation of the entire battery pack (i.e., the assembly of all battery cells connected to the conductors).

[0008] Most current battery packs require a welded connection D between the cell and the electrical conductor, for both the power path and the signal path (e.g., monitoring the voltage of individual cells). In this situation, known types of apparatus have proven in practice to be not free of drawbacks. The main drawback lies in the fact that the welded connection is costly and complex to achieve. Indeed, each battery (or battery cell) necessarily has to be connected with two welds — one for each end or pole — increasing the connection time, costs, and requiring specialized operators in precision welding.

[0009] Another drawback is that if a battery or cell stops working or malfunctions, the entire apparatus needs to be disassembled and replaced with a new one provided with all new batteries to restore the battery pack to its original capacity. Therefore, the maintenance of known types of connecting apparatus is very complex and extremely costly.

[0010] Another drawback, as a consequence of what has been described so far, is that known types of apparatus necessarily waste a lot of material every time maintenance is required, making them extremely polluting. Furthermore, known apparatus typically involves applying a mechanical load, for example, through suitable tie rods, in a direction perpendicular to the conductors, to press the conductors themselves onto the cell poles. Due to the necessary dimensional tolerances on the axial length of the cells, a parameter generally not controlled by the battery pack manufacturer but depending directly on the production process of the individual cells, such an assembly does not always guarantee contact between pole and conductor for all cells, as some cells or batteries might be shorter than the linear distance between the two conductors.

[0011] OBJECTIVES OF THE INVENTION

[0012] The objective of the present invention is to provide an apparatus for connecting electric batteries that can at least partially overcome the drawbacks of the known technique mentioned above.

[0013] Another objective of the present invention is to provide an apparatus for connecting electric batteries that allows the batteries to be connected to the conductors quickly and easily, ensuring at the same time a secure and safe mechanical connection for any application.

[0014] Another objective of the present invention is to provide an apparatus for connecting electric batteries that simplifies assembly and reduces the costs of connecting the batteries to the conductors.

[0015] Another objective of the present invention is to provide an apparatus for connecting electric batteries that allows quick and easy maintenance and, in particular, the replacement of each individual battery.

[0016] Another objective of the present invention is to provide an apparatus for connecting electric batteries that is functionally and structurally completely safe and reliable.

[0017] Another objective of the present invention is to provide apparatus for connecting electric batteries that allows quick disassembly of each battery and facilitates its recycling.

[0018] Another objective of the present invention is to provide apparatus for connecting electric batteries that constantly ensures the connection of all batteries to the conductors, regardless of their length variability.

[0019] Another objective of the present invention is to provide an apparatus for connecting electric batteries that has an improved or alternative configuration compared to the known technique.

[0020] SUMMARY OF THE INVENTION

[0021] All objectives, both individually and in any combination thereof, and others that will become apparent from the detailed description that follows, are achieved, according to the invention, with apparatus for connecting electric batteries having the characteristics indicated in independent claim 1.

[0022] In particular, the aforementioned objectives are achieved with apparatus for connecting electric batteries, comprising: at least one first electrical conductor with at least one substantially planar first face; at least one second electrical conductor with at least one substantially planar second face facing said first face; wherein said first conductor element and said second conductor element define between said first face and said second face a housing volume configured to house at least one battery extending transversely between said first conductor with a first pole and said second conductor with a second pole; characterized by comprising elastically yieldable connecting means provided on said first face of said first electrical conductor and / or on said second face of said second electrical conductor and configured to be interposed between said first face and said first pole and / or said second face of said second pole; said connecting means having a decreasing non-linear elastic modulus to ensure a substantially constant pushing force on said battery against said conductors. Advantageously, said elastically yieldable connecting means have a convex elastic characteristic comprising a first zone with increasing pushing force with deformation and a second zone with a substantially constant pushing force regardless of the deformation. Advantageously, said connecting means are configured to operate in said second zone of said elastic characteristic to push said battery against said first or said second face with a constant force regardless of the length of said battery. Advantageously, said connecting means comprise at least one cup spring arranged on said first face of said first electrical conductor and / or on said second face of said second electrical conductor. Advantageously, said connecting means comprise at least two cup springs arranged side by side in parallel on said first face of said first electrical conductor and / or on said second face of said second electrical conductor. Advantageously, said connecting means comprise at least two cup springs arranged in series on said first face of said first electrical conductor and / or on said second face of said second electrical conductor. Advantageously, said cup spring of said connecting means has a substantially truncated conical shape and extends tapering from a widened base. Advantageously, said connecting means comprise at least two cup springs arranged one above the other at the respective widened bases. Advantageously, the apparatus comprises an electrically conductive element disposed on said elastically yieldable connecting means and electrically connected to said first conductor or said second conductor to be interposed between said connecting means and said battery to improve the electrical connection. Advantageously, said elastically yieldable connecting means have decreasing stiffness with travel, such that they apply a constant force regardless of the compression travel.

[0023] BRIEF DESCRIPTION OF THE FIGURES

[0024] The present invention is further clarified in some of its preferred embodiments of practical realization, provided for purely illustrative and non-limiting purposes, with reference to the attached drawing sheets, in which:

[0025] Figure 1 shows a sectional view of apparatus for connecting electric batteries of a known type, forming part of the above-described state of the art;

[0026] Figure 2 shows a sectional view of the apparatus for connecting electric batteries according to the present invention;

[0027] Figure 3 shows an exploded perspective view of a detail of the apparatus according to the invention, concerning elastically yieldable connecting means interposed between the conductor and a battery;

[0028] Figure 4A shows an illustrative and non-limiting graph of the convex elastic characteristic of non-linear elastically yieldable connecting means comprising a single non-linear spring;

[0029] Figure 4B shows an illustrative and non-limiting graph of the convex elastic characteristic of non-linear elastically yieldable connecting means comprising two non-linear springs in parallel;

[0030] Figure 4C shows an illustrative and non-limiting graph of the convex elastic characteristic of non-linear elastically yieldable connecting means comprising two non-linear springs in series.

[0031] Figure 5 shows a sectional view of the apparatus for connecting electric batteries according to the present invention, highlighting the deformation when the first and second conductors are brought closer together.

[0032] DETAILED DESCRIPTION OF THE INVENTION

[0033] With reference to the attached figures, an apparatus for connecting electric batteries, which is the subject of this invention, is wholly indicated by 1, which is specifically designed to mechanically contain and electrically connect at least one, and preferably a plurality of, electric batteries, also known as battery cells.

[0034] Preferably, the apparatus 1 according to the invention is configured to contain and connect batteries B of substantially cylindrical shape, such as, for example, 18650 or 21700 batteries, which are known to those skilled in the art.

[0035] The apparatus 1 according to the invention is preferably configured to house a plurality of batteries B and electrically connect them in parallel.

[0036] Conveniently, in use, two or more pieces of apparatus 1 according to the invention can be used side by side to increase electrical capacity.

[0037] According to the invention, the apparatus 1 for connecting electric batteries B comprises at least a first electric conductor 2 with at least one substantially planar first face 2’. Advantageously, the first electric conductor 2 is made by means of a plate of electrically conductive material, for example metallic material, such as copper or aluminum, or any other material known to those skilled in the art and suitable for conducting electric energy.

[0038] The apparatus according to the invention also comprises at least a second electric conductor 3 provided with at least one substantially planar second face 3’ facing said first face 2’ of said first electric conductor 2.

[0039] More specifically, the first electric conductor 2 is preferably arranged parallel to the second electric conductor 3.

[0040] The first electric conductor 2 and the second electric conductor 3 define between said first face 2’ and said second face 3’ a housing volume 4 configured to accommodate at least one battery B extending transversely between said first conductor 2 with a first pole Pl and said second conductor 3 with a second pole P2.

[0041] In accordance with the exemplary and non-limiting embodiment illustrated in the attached figures, each battery B (which is known per se and therefore not part of the apparatus object of the invention) can comprise a main body Bl, preferably of substantially cylindrical shape, extending between two ends on which the first pole Pl and the second pole P2 are respectively provided. For example, the first pole Pl may protrude from the main body Bl and the second pole P2 may be provided at the end of the main body Bl, flush with this end.

[0042] According to the invention, the apparatus 1 comprises elastically yielding connection means 5 provided on said first face 2’ of said first electric conductor 2 and / or on said second face 3’ of said second electric conductor 3 and configured to be interposed between said first face 2’ and said first pole Pl of said battery and / or said second face 3’ of said second pole P2. The connection means 5 have a non-linear convex elastic characteristic presenting a zone with low or null elastic modulus or stiffness to ensure a substantially constant push force despite the tolerances on said battery B against said conductors 2, 3.

[0043] Advantageously, with particular reference to the attached figures 4A — 4C, said elastically yielding connection means 5 have a decreasing elastic modulus comprising a first zone Z1 with increasing push force with deformation and a second zone Z2 with substantially constant push force regardless of deformation.

[0044] More specifically, due to dimensional tolerances on the axial length L of the cells (see Figure 2), which are generally not controllable by the manufacturer of the apparatus 1 but depend on the production process of the individual batteries B, it is generally not possible to guarantee contact between poles Pl, P2 and conductors 2, 3 for all cells which may have different lengths L and therefore may not reach the first and / or second face 2’, 3’ of the conductors 2, 3. In this situation, the elastically yielding connection means 5 allow the battery B to reach the conductors 2, 3 regardless of the length L difference. In particular, to ensure contact between the poles Pl, P2 and the conductors 2, 3 of all cells, an axial load is applied to the conductors 2, 3 towards the housing volume 4 to bring the conductors closer together, eliminating any spaces between the poles and the conductors due to the above-mentioned dimensional differences between the lengths L of the cells. As shown in Fig. 5, applying an axial load to bring the conductors 2, 3 closer together, e.g., by means of joining devices 9 such as bolts, causes local deformation S on these conductors 2, 3 due to the reaction force of the elastically yielding connection means 5 transmitted through the cell. Therefore, as a result of applying an axial load, these conductors 2, 3 have a raised surface portion 10 due to the push force of the cell. As can be understood, to minimize the presence of such local deformations, more rigid or thicker conductors can be used, e.g., metal plates with increased thickness, however causing an increase in weight and overall size of the apparatus for connecting electric batteries. According to an alternative embodiment of the present invention, the conductors 2, 3 can be made to counteract the formation of local raised surfaces 10 when in use, i.e., under the action of the reaction forces of the elastically yielding connection means 5 transmitted through the cells. In particular, it is possible to make conductors 2, 3 with locally predeformed surface portions so that when the conductors are mounted on the apparatus, these pre-deformed surface portions are facing each other, axially protruding towards the housing volume 4. In particular, these surface portions are pre-deformed on the surface portion on which the reaction force transmitted by each cell acts in use. Consequently, before an axial load is applied to bring the conductors 2, 3 closer together, it is possible to see recessed surface portions on the surfaces opposite those facing the housing volume 4. In this way, when an axial load is applied to the conductors 2, 3 to bring them closer, each cell applies a reaction force on the pre-deformed surface portion causing an opposite direction deformation of that surface, making the latter substantially parallel to the remaining surface of the corresponding conductor 2, 3. As can be understood, to achieve pre-deformation on the conductors 2, 3 it is necessary to know the load applied in use, e.g., through bolt tightening, and the corresponding local deformation on the conductor surface portions so as to produce in the manufacturing phase of the conductors a comparable deformation on a conductor surface portion but made in the opposite direction to that produced by the push force of the cells. The present invention thus proposes to use elastically yielding connection means 5 that have a decreasing non-linear elastic modulus with compression stroke, so as to present a “flat” elastic modulus section or zone Z2, i.e., in other words, a working section or zone Z2 where the reaction force of the connection means 5 remains constant with the compression stroke. In this way, the apparatus 1 according to the invention allows for electrically connecting and mechanically retaining the batteries B regardless of their length L. Additionally, the use of elastically yielding connection means 5 with a convex non-linear elastic characteristic ensures a constant contact resistance. In fact, as is known, the contact resistance between the connection means 5 and the poles Pl, P2 depends on the pressure exerted on the poles themselves. Consequently, as the compression force of the connection means 5 varies, the contact resistance varies. The decreasing elastic modulus of the connection means 5 of the apparatus according to the invention ensures an electrical contact with constant resistance regardless of the length L of the batteries B since the compression in the second zone Z2 remains substantially constant.

[0045] Advantageously, as described above, said connection means 5 are configured to act in said second zone Z2 of said elastic characteristic to push said battery B against said first or said second face 2’, 3’ with constant force regardless of the length L of said battery B.

[0046] Advantageously, according to a first embodiment of the present invention, said connection means 5 comprise at least one cup spring 6 arranged on said first face 2’ of said first electric conductor 2 and / or on said second face 3’ of said second electric conductor 3. An example of a convex non-linear elastic characteristic of connection means 5 comprising a single cup spring 6 is illustrated in the attached figure 4A.

[0047] Advantageously, according to a second embodiment of the present invention, said connection means 5 comprise at least two cup springs 6 arranged side by side in parallel on said first face 2’ of said first electric conductor 2 and / or on said second face 3’ of said second electric conductor 3. An example of a convex non-linear elastic characteristic of connection means 5 comprising two cup springs 6 arranged in parallel is illustrated in the attached figure 4B. Advantageously, according to a third embodiment of the present invention, said connection means 5 comprise at least two cup springs 6 arranged one on top of the other in series on said first face 2’ of said first electric conductor 2 and / or on said second face 3’ of said second electric conductor 3. An example of a convex non-linear elastic characteristic of connection means 5 comprising two cup springs 6 arranged in series is illustrated in the attached figure 4C.

[0048] Advantageously, said cup spring 6 of said connection means 5 has a substantially firusto- conical shape and extends tapering from a widened base.

[0049] Advantageously, said connection means 5 comprise at least two cup springs 6 arranged one on top of the other at their respective said widened bases.

[0050] Moreover, as previously mentioned, the cup spring 6 can achieve a differently convex elastic characteristic curve based on the project requirements by varying the arrangement of two or more cup springs.

[0051] Additionally, the cup spring 6 exhibits high fatigue resistance under dynamic load and a low tendency to deform.

[0052] As previously described, the cup springs 6 of the connection means 5 can be stacked or placed side by side to modify the convex non-linear elastic characteristic curve (see figures 4A-4C).

[0053] Appropriately, stacking cup springs 6 in the same direction results in the elasticity constant of the resultant spring being substantially equal to the sum of the elasticity constants of all the stacked cup springs, leading to the creation of a stiffer spring (with the same stroke). Stacking cup springs in alternating directions results in the same effect as the series arrangement of helical springs, resulting in a spring with a lower elastic constant and, under the same load, a greater stroke. The possibility of arranging cup springs 6 in multiple configurations allows for obtaining a wide range of stiffness and stroke values for the resultant spring, which can be custom- designed for each application.

[0054] Advantageously, the apparatus comprises an electrically conductive element 8 arranged on said elastically yielding connection means 5 and electrically connected to said first conductor 2 or said second conductor 3 to be interposed between said connection means 5 and said battery B to improve the electrical connection.

[0055] Advantageously, said elastically yielding connection means 5 exhibit decreasing stiffness with stroke, such that a constant force is applied despite the variation in compression stroke.

[0056] From the foregoing, it is clear that the apparatus for connecting electric batteries, according to the invention, is particularly advantageous because: it is able to overcome, at least in part, the disadvantages of the known technique mentioned above; it allows for quick and easy connection of the batteries to the conductors, ensuring a secure and reliable mechanical connection for any application; it simplifies assembly and reduces the cost of connecting the batteries to the conductors; it allows for quick and easy maintenance and, in particular, enables the individual replacement of each battery B; it is completely safe and reliable both functionally and structurally; it allows for the quick disassembly of each battery and facilitates its recycling; it constantly ensures the connection of all batteries to the conductors, regardless of their length variability; it can be manufactured industrially using known fabrication techniques; it presents an alternative and / or improved configuration, both in construction and functionality, compared to traditional known solutions.

Claims

CLAIMS1. Apparatus for connecting electric batteries, comprising:— at least one first electric conductor (2) provided with at least one first face (2’) which is substantially planar;— at least one second electric conductor (3) provided at least a second substantially planar face (3’) facing said first face (2’); said first conductive element (2) and said second conductive element (3) defining between said first face (2’) and said second face (3’) a housing volume (4) configured to house at least one battery (B) extending transversely between said first conductor (2) with a first pole (Pl) and said second conductor (3) with a second pole (P2); characterized in that it comprises connection means (5) elastically deformable provided on said first face (2’) of said first electrical conductor (2) and / or on said second face (3’) of said second electrical conductor (3) and configured to be interposed between said first face (2’) and said first pole (Pl) and / or said second face (3’) of said second pole (P2); said connection means (5) having a decreasing non-linear elastic modulus to ensure a substantially constant thrust force to said battery (B) against said conductors (2, 3).

2. Apparatus for connecting electric batteries according to claim 1, characterized in that said elastically deformable connection means (5) have a convex non-linear elastic characteristic comprising a first zone (Zl) with a thrust force increasing with deformation and a second zone (Z2) with a substantially constant thrust force regardless of the deformation.

3. Apparatus for connecting electric batteries according to claim 2, characterized in that said connection means (5) are configured to act in said second zone (Z2) of said elastic module to push said battery (B) against said first or said second face (2’, 3’) with constant force regardless of the length (L) of said battery (B).

4. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that said connection means (5) comprise at least one cup spring (6) arranged on said first face (2’) of said first conductor electrical conductor(2) and / or on said second face (3’) of said second electrical conductor (3).

5. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that said connection means (5) comprise at least two cup springs (6) arranged facing each other in parallel on said first face (2’) of said first electrical conductor (2) and / or on said second face (3’) of said second electrical conductor(3).

6. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that said connection means (5) comprise at least two cup springs (6) arranged superimposed on each other in series on said first face (2’) of said first electrical conductor (2) and / or on said second face (3’) of said second electrical conductor (3).

7. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that said cup spring (6) of said connection means (5) has a substantially truncated cone shape and extends tapering from an enlarged base.

8. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that said connection means (5) comprise at least two cup springs (6) arranged superimposed on each other in correspondence with the respective said enlarged bases.

9. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that it comprises an electrically conductive element (8) arranged on said elastically deformable connection means (5) and electrically connected to said first conductor (2) or said second conductor (3) to be arranged in between saidconnection means (5) and said battery (B) to improve the electrical connection.

10. Apparatus for connecting electric batteries according to one or more of the preceding claims, characterized in that said elastically deformable connection means (5) have decreasing stiffness with the stroke, so as to apply a constant force as the compression stroke varies.

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