Electric vehicle energy storage system

Abstract

To provide a power storage system that is thermally insulating and inhibits an increase in the overall dimensions as well as in weight thereof.SOLUTION: A power storage system 1 comprises: at least one battery pack 2 which is provided with a plurality of electrochemical cells 5 which are electrically connected to one another; a container 3 which is provided, on the inside, with a chamber 4 housing the battery pack; at least one first connector which is mounted on the container; and a covering casing 7 which is designed to thermally insulate the container and protect the container from fire. The covering casing is made of a fireproof fabric, which is also thermally insulating and is in direct contact with an outer surface of the container.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This patent application claims priority to Italian Patent Application No. 102019000013545, filed July 31, 2019, the entire disclosure of which is hereby incorporated by reference.

[0002] The present invention relates to an electricity storage system for an electric vehicle. [Background technology]

[0003] In particular, an electrical storage system for an electric vehicle is known, the electrical storage system comprising at least one battery pack having a plurality of electrochemical cells electrically connected in series and / or parallel with one another, an inner container defining a chamber for receiving the battery pack, and an electrical connector protruding from the inner container for connecting the battery pack to a drive system of the electric vehicle.

[0004] The known power storage system further comprises a cover container, which is disposed outside the inner container and is designed to enable the inner container (and therefore the battery pack) to be sufficiently fire-resistant and to insulate the inner container (and therefore the battery pack).

[0005] In detail, the cover container of the known energy storage system is made from a metallic material, typically steel or an aluminum alloy, and is arranged at a given distance from the inner container, so that an air space is defined between the inner container and the cover container, the air space being adapted to ensure that the inner container (and therefore the battery pack) is properly insulated, thus avoiding the risk that heat coming from the outside may overheat the battery pack and thus cause damage or, in a worst case scenario, explosion of one or more electrochemical cells.

[0006] In order for an energy storage system to pass the mandatory and increasingly stringent fire tests required to obtain type approval (i.e. approval that the covering container is capable of delivering the correct values ​​of fire resistance and thermal insulation), the covering container and air space must have a thickness such that the battery pack inside the inner container does not exceed 120° C., even if the energy storage system is exposed to an open flame at a temperature of approximately 1200° C. These performances can only be ensured by a covering container and air space having a significant thickness.

[0007] However, the increase in thickness of the cover container and air space leads to an increase in the overall size of the power storage system and an increase in its weight, which can be problematic in automotive applications where weight and size reduction is increasingly necessary, especially if the power storage system has to be installed in a sports car that demands high performance but offers small interior space.

[0008] US Patent No. 5,399,633 describes an insulating covering casing for a vehicle battery that protects the battery from low temperatures during winter, and is flexible and can be folded to assume a flat configuration so that it can be easily stored when not in use. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] UK Patent Application No. 2213981 Summary of the Invention

[0010] SUMMARY OF THE DISCLOSURE The object of the present invention is to provide an energy storage system for an electric vehicle that is able to overcome the drawbacks explained above and that is easy and economical to manufacture.

[0011] According to the present invention, there is provided a power storage system for an electric vehicle according to the accompanying claims.

[0012] The appended claims describe preferred embodiments of the invention and form an integral part of this specification.

[0013] The present invention will now be described with reference to the accompanying drawings, which show non-limiting embodiments of the invention. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic perspective view of an energy storage system for a drive system of an electric vehicle according to the present invention; [Diagram 2] 2 is a schematic perspective view of the electricity storage system of FIG. 1 with a cover casing removed. FIG. [Diagram 3] FIG. 2 is a cross-sectional view of the power storage system of FIG. [Figure 4] FIG. 2 is a schematic cross-sectional view, on an enlarged scale, of a cover casing of the power storage system of FIG. 1. [Diagram 5] FIG. 2 shows a detail of FIG. 1 on an enlarged scale, with the patch placed in a protective position. [Figure 6] FIG. 2 shows a detail of FIG. 1 on an enlarged scale, with the patch placed in a lifted position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In the accompanying drawings, the numeral 1 generally indicates an energy storage system adapted to be mounted on an electric vehicle (not shown here).

[0016] In particular, the energy storage system 1 is adapted to be connected to a drive system (not shown here) of an electric vehicle and is designed to store power generated by an electric machine (not shown here), which is connected to the electric machine through the intervention of a power converter (commonly known as an inverter) that converts the direct current output by the energy storage system 1 into an alternating current for the electric machine and vice versa, based on the different needs of the electric machine and the energy storage system 1.

[0017] The energy storage system 1 shown in the accompanying drawings comprises a battery pack 2 and a container 3 (typically made from an electrically insulating plastic material) defining an internal chamber 4 for housing the battery pack 2.

[0018] In particular, the battery pack 2 comprises a plurality of electrochemical cells 5 that are electrically connected to each other in series and / or parallel and designed to convert stored chemical energy into electrical energy and vice versa. The electrochemical cells 5 are preferably Li-Ion cells (lithium ion batteries).

[0019] According to a preferred, but non-limiting embodiment shown in FIG. 3, each electrochemical cell 5 has a substantially parallelepiped shape and has a positive electrode at one end and a negative electrode at the other end.

[0020] Advantageously, but not exclusively, the electrochemical cells 5 are divided into battery modules 6 each housing a given number of electrochemical cells 5, and the battery modules 6 are electrically connected to each other in series or parallel. For example, in the non-limiting example shown in FIG. 3, 20 battery modules 6 are provided, which are stacked on top of each other to form the battery pack 2.

[0021] Each battery module 6 can, of course, include any number of electrochemical cells 5, and the battery pack 2 can, of course, include any number of battery modules 6. It is further understood that the electrochemical cells 5 can have any shape and / or size, for example, according to an embodiment not shown herein, the electrochemical cells 5 can have a cylindrical shape and be disposed adjacent to one another within the container 3.

[0022] The storage system 1 shown in the attached drawings further comprises a cover casing 7, which is designed to insulate the container 3 and protect it from fire. The cover casing 7 is made of fire-resistant fibers, which are also insulating and are in direct contact (i.e., in contact without gaps) with the outer surface 8 of the container 3. In other words, the fibers that make up the cover casing 7 are more fire-resistant than the (generally plastic) material that makes up the container 3, because the fibers that make up the cover casing 7 are more resistant to burning than the (generally plastic) material that makes up the container 3. Furthermore, the fibers that make up the cover casing 7 are more insulating than the (generally plastic) material that makes up the container 3, because the fibers that make up the cover casing 7 have a lower thermal conductivity than the (generally plastic) material that makes up the container 3. In particular, the fibers that make up the cover casing 7 are flexible, i.e., they can be elastically deformed (i.e., deformed without undergoing plastic deformation) even when bent more than 90 degrees to take different shapes.

[0023] In detail, the cover casing 7 is formed to replicate the shape of the container 3 and to fit closely to the container 3 without any gaps.

[0024] According to a preferred, but non-limiting embodiment shown in FIG. 4, the fire-resistant fabric constituting the cover casing 7 comprises two outer fire-resistant layers 9 made of non-woven fabric fabric (preferably reinforced with glass fibers) and an inner layer 10 sandwiched between the two outer fire-resistant layers 9, made of a fiber cloth (preferably reinforced with glass fibers) and designed to provide higher thermal insulation than the two outer fire-resistant layers 9.

[0025] According to the embodiment shown in Figures 1 and 2, the container 3 is provided with at least one power connector 11, which is designed to receive at least one linear connection element (i.e. an electric cable not shown here), which terminates in a further connector (not shown) which engages with the connector 11 and which is designed to connect the energy storage system 1 to a vehicle, i.e. to the drive system of the vehicle.

[0026] According to FIG. 6, the cover casing 7 has a through hole 12 within the area of ​​the power connector 11, and the through hole 12 has an area (extension) greater than or equal to the area (extension) of the power connector 11 so as to allow the further connector to engage with the power connector 11 and for parts of the further connector and / or parts of the linear connecting element to exit from the cover casing 7.

[0027] In order to avoid the risk that the through holes 12 will excessively weaken the cover casing 7 (in terms of heat) and thus impair its fire-resistant capabilities, the cover casing 7 is preferably provided with a patch 13 which is arranged within the area of ​​the through holes 12 and which is designed to at least partially close the through holes 12 and at the same time allow the linear connecting element to exit the cover casing 7.

[0028] In detail, the patch 13 is movably fixed to a rest of the cover casing 7, so that the patch 13 can be moved between a raised position (shown in FIG. 6) in which the patch 13 is spaced away from the rest of the cover casing 7 so as not to block the through hole 12, and a protected position (shown in FIG. 5) in which the patch 13 is placed against the rest of the cover casing 7 so as to partially block the through hole 12.

[0029] In particular, the patch 13 further has a through hole 14 on the inside, which is smaller than the through hole 12 (i.e., has an area smaller than the through hole 12 and can be entirely contained inside the through hole 12) and is designed so that the linear connecting element passes through it without having a gap, at least when the patch 13 is in the protective position. In other words, when the patch 13 is in the protective position, the patch 13 closes a part of the through hole 12 from which the linear connecting element comes out, so that the linear connecting element penetrates the patch 13 and thus enters the through hole 14, and in particular occupies the entire through hole 14 (i.e., is in close contact with the wall of the through hole 14).

[0030] Advantageously, the through holes 14 are sized to be penetrated by the linear connecting elements without gaps, thereby minimizing the risk of leaving spaces between the linear connecting elements and the through holes 14 that would allow heat and / or flames to penetrate, thus ensuring better fire resistance performance of the cover casing 7.

[0031] According to the embodiment shown in Figures 5 and 6, the patch 13 has at least one through cut 15, which starts from the through hole 14 and leads to the outer free edge 16 of the patch 13. In particular, the patch 13 is configured to take an open configuration in which two flaps 17 of the cut 15 are spaced apart from each other and are designed so that the patch 13 is penetrated by the linear connecting element in order to place the linear connecting element inside the through hole 14, and a closed configuration (shown in Figure 5) in which the flaps 17 of the cut 15 partially overlap each other in order to close the cut 15 and define the extent of the through hole 14 and ensure that the linear connecting element is in close contact with the edge of the through hole 14 without any gaps.

[0032] For fixing the patch 13 to the rest of the cover casing 7, once the patch 13 is in the protective position (according to Fig. 5) and in the closed configuration, fastening means 18 are provided. In particular, according to a preferred embodiment, the fastening means comprises (consists of) at least one metal press stud 18, which is designed to fix at least one of the flaps 17 (or both flaps 17) to the rest of the cover casing 7. In particular, the metal press stud 18 can be arranged in the area where the two flaps 17 overlap each other, or according to another alternative (shown in Figs. 5 and 6), two metal snap buttons 18 can be provided, one on each side of each flap 17.

[0033] In the embodiment shown in the accompanying drawings, the energy storage system 1 comprises, in addition to the power connector 11, a signal connector which is separate and independent from the power connector 11. According to this embodiment, within the area of ​​each electrical connector (either the power connector 11 or the signal connector), the cover casing 7 has an associated through hole 12 and an associated patch 13 covering the through hole 12.

[0034] The storage system 1 further comprises a hydraulic connector 19, which is designed to circulate a cooling fluid in the container 3 in order to cool the storage system 1. In the area of ​​the hydraulic connector 19, the cover casing 7 has an associated through-hole 12, which is not covered by the patch 13 (because the hydraulic pipe, i.e. the linear connecting element, has a shape and size as its own connector, which engages with the hydraulic connector 19). See for example Figures 1, 5 and 6 in this regard.

[0035] The cover casing 7 further comprises at least a plurality of stabilization wings 20, each of which is mounted on a portion of the cover casing 7 and secured to the cover casing 7 (i.e., to the above-mentioned portion of the cover casing 7) by a metal snap button 21.

[0036] In particular, the stabilizing wings 20 are arranged in the corner areas of the container 3 or in protruding areas, for example areas above hydraulic pipes surrounding the container 3 .

[0037] The metal snap button 21 can of course be replaced by any other fastening element having the same function.

[0038] The above described power storage system 1 has many advantages.

[0039] Firstly, the above described energy storage system 1 has small dimensions compared to known cover containers, because the energy storage system 1 comprises a cover casing 7 which is sealed to the container 3 without any gaps and therefore without any further spaces or layers.

[0040] Furthermore, since the cover casing 7 is made from textiles, the cover casing 7 has a weight that is significantly smaller than the weight of known cover containers that have a metal layer with a significant thickness.

[0041] In other words, the solution proposed here reduces the weight and size of the energy storage system 1, given the same effectiveness.

[0042] Furthermore, the above described energy storage system 1 can be easily mounted onto and / or removed from the container 3 by simply overlapping the ends of the cover casing 7 with each other and fastening them to each other, preferably by metal snap buttons 21 (see FIG. 1 ).

[0043] Finally, the above described power storage system 1 is simple and economical to manufacture. [Explanation of symbols]

[0044] 1. Energy storage system 2 Battery pack 3 Container 4 Chambers 5. Electrochemical Cell 6 Battery Module 7 Cover Casing 8 External surface 9 Outer fireproof layer 10 Inner layer 11 Connectors 12 Through hole 13 Patch 14 Through hole 15 Cutting 16 Outer free edge 17 Flap 18 Fastening means / metal snap button 19 Hydraulic Connector 20 Stabilizing wing 21 Fastening means / metal snap button

Claims

1. A power storage system (1) for an electric vehicle, At least one battery pack (2) provided with a plurality of electrochemical cells (5) electrically connected to one another; A container (3) having a chamber (4) therein for accommodating the battery pack (2); At least one first connector (11) mounted on said container (3) and designed to engage with a second connector from which a linear connecting element originates; a cover casing (7) in direct contact with an outer surface (8) of the container (3), made of flexible fabric and designed to insulate the container (3) and protect it from fire, the insulation and protection from fire being achieved by the cover casing (7) having a higher fire resistance than the material constituting the container (3) and a lower thermal conductivity compared to the material constituting the container (3), the cover casing (7) having a first through hole (12) aligned with the connector (11) to allow access to the connector (11) through the cover casing (7) and having an area equal to or greater than the area of ​​the connector (11); The storage system (1) comprises: the cover casing (7) is movably fixed to a base of the cover casing (7), and is disposed within the area of ​​the first through hole (12) so as to cover the first through hole (12), and is provided with a patch (13) having a second through hole (14) on the inside, the second through hole (14) having an area smaller than that of the first through hole (12) and designed so that the linear connecting element of the second connector passes through the second through hole without having a gap; the patch (13) is movable relative to the cover casing (7) between a raised position in which the patch (13) is spaced from the base of the cover casing (7) so as not to cover the first through hole (12) and a protected position in which the patch (13) is placed against the base of the cover casing (7) so as to partially cover the first through hole (12); 13. The electrical storage system according to claim 12, wherein the patch (13) has at least one cut (15) starting from the second through hole (14) and reaching an outer free edge (16) of the patch (13), whereby the patch (13) has an open configuration in which two flaps (17) of the cut (15) are spaced apart from each other and the patch (13) is designed to be penetrated by the linear connection element in order to place the linear connection element inside the through hole (14), and a closed configuration in which the flaps (17) of the cut (15) partially overlap each other to close the cut (15) and define the extent of the through hole (14) and ensure that the linear connection element is in close contact with the edge of the through hole (14) without any gaps.

2. 2. The energy storage system (1) according to claim 1, wherein the cover casing (7) is formed to replicate the shape of the container (3) and to fit closely to the container (3) without any gaps.

3. 3. The storage system (1) according to claim 1 or 2, wherein the cover casing (7) comprises first fastening means (18) for fastening the patch (13) to a base of the cover casing (7).

4. 4. The energy storage system (1) according to claim 3, wherein the first fastening means (18) consists of a metal snap button.

5. 5. The energy storage system (1) according to claim 4, wherein each flap (17) of the patch (13) is provided with its own metal snap button designed to fasten the patch (13) to a mount of the cover casing (7).

6. 6. The energy storage system (1) according to any one of claims 1 to 5, comprising a first electrical power connector (11), a second electrical signal connector and a hydraulic connector (19) allowing a cooling fluid to circulate within the container (3).

7. The storage system (1) according to any one of claims 1 to 6, wherein the cover casing (7) is a plurality of stabilizing wing sections (20) each mounted on a separate portion of the cover casing (7); a plurality of second fastening means (21) for fastening each of the stabilizing wing sections (20) to a corresponding portion of the cover casing (7); The power storage system includes:

8. The storage system (1) according to any one of claims 1 to 7, the cover casing is made of fire-resistant fiber; The fire-resistant fiber is Two outer fire-resistant layers (9) made from nonwoven fibers; an inner layer (10) sandwiched between the two outer fire-resistant layers (9), made from a textile fabric and designed to provide greater thermal insulation than the two outer fire-resistant layers (9); 2. A power storage system comprising:

9. The energy storage system (1) according to claim 8, The two outer fire-resistant layers (9) are made of non-woven fabric reinforced with glass fibers, The electrical storage system, wherein the inner layer (10) is made of a fiber cloth reinforced with glass fibers.

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