Intermediate device for electrical storage device

Abstract

Title: Intermediate device for electrical storage device The present invention relates to an intermediary device (6) configured to extend between two rows (4) of batteries (2) of an electrical storage device (1), the intermediary device (6) extending mainly in a longitudinal direction (L) and having at least one inner body covered with an outer layer, the inner body and the outer layer being made respectively of a first material and a second material different from the first material, the second material having a surface tension greater than a surface tension of the first material. (figure 2)

Description

Title of the invention: Intermediate device for electrical storage device

[0001] The present invention relates to the field of electrical storage devices intended for use within an electric or hybrid vehicle.

[0002] Electrical storage devices are commonly used in motor vehicles, whether electric or hybrid, to provide the vehicle with electrical energy for its movement. Such electrical storage devices usually comprise a plurality of electrical storage cells, or batteries, organized in a battery box within which at least one cooling device is arranged. The cooling device ensures in particular the cooling of the batteries by capturing their calories in order to limit the phenomena of overheating of the electrical storage device.

[0003] The type of electrical storage cells may differ from one electrical storage device to another, but it is known to have cells that each have a cylindrical shape, the cells being organized in rows of batteries. In this context, the cooling device comprises cooling tubes extending respectively between the rows of cells and within which circulates a cooling fluid, distributed and collected by appropriate chambers arranged at the ends of the tubes and connected to each other. It is known to provide intercalary devices, which have the same shape as the cooling tubes, in order to arrange them between certain rows of cells. These intercalaries allow, like the cooling tubes, to maintain the rows of cells at regular intervals from each other, but they do not have a cooling function.This makes it possible, in particular, to not make the interposed devices in the same metallic material as the cooling tubes, and to use less expensive and lighter thermoplastic materials.

[0004] Furthermore, the cells are held in place relative to each other, particularly within the same row of cells, by means of a bonding material injected into the battery box. For example, the bonding material may be an epoxy resin.

[0005] One problem with current electrical storage devices lies in the adhesion of the bonding material to the interlayer devices. As mentioned, the interlayer devices used in electrical storage devices can be made of polypropylene in order to limit the costs and complexity of producing these devices. However, such a material has poor adhesion to the bonding material. bonding such as epoxy resin which has the effect of limiting the bonding performance and therefore the holding of the cells in relation to each other.

[0006] Thus, the aim of the invention is to propose an intercalary device whose adhesion with the bonding material is improved in order to optimize the solidity of the electrical storage device and in particular the maintenance of the cells in rows relative to each other.

[0007] The invention therefore relates to an interposed device configured to extend between two rows of batteries of an electrical storage device, the interposed device extending mainly in a longitudinal direction and having at least one internal body covered with an external layer, the internal body and the external layer being made respectively of a first material and a second material different from the first material, the second material having a surface tension greater than a surface tension of the first material.

[0008] The electrical storage device is used within an electric or hybrid motor vehicle and has the function, in particular, of supplying power to an electric motor for moving said vehicle. The electrical storage device comprises for this purpose at least two rows of batteries which store electrical energy and at least one interposed device arranged between the two rows of batteries, these being housed in a battery box into which a bonding material is injected. The bonding material has the function, in particular, of fixing the position of the batteries within the box, relative to each other and also relative to the interposed device, by adhering at least in part to each of these elements.

[0009] As mentioned, the interlayer device according to the invention comprises an inner body made of a first material and an outer layer, covering the inner body, made of a second material distinct from the first material in that the surface tension of the second material is greater than the surface tension of the first material. Advantage is then taken of the high surface tension of the second material, intended to form the outer layer of the interlayer device, in contact with the bonding material, in that this provides better adhesion with the bonding material. More precisely, the second material allows better adhesion with an epoxy resin which can form the bonding material.This improves the retention of the battery rows within the electrical storage device's housing by using this second material, while ensuring a lightweight and inexpensive design, since the first material, with its lower surface tension, is used to make the internal core of the interlayer device.

[0010] According to a characteristic of the invention, the first material comprises a first viscosity rate and the second material comprises a second viscosity rate, the first viscosity rate being higher than the second viscosity rate, preferably at least 15% higher, preferably 50% higher, preferably 100% higher than the second viscosity rate of the second material. Advantage is taken of having a first viscosity rate higher than the second viscosity rate in that it makes it possible to improve the separation of the first material and the second material during a manufacturing process of the intercalary device. More precisely, the difference in viscosity between the first material and the second material allows the latter to coat the first material during the manufacturing process of the intercalary device.

[0011] According to a characteristic of the invention, the first material is polypropylene.

[0012] According to a characteristic of the invention, the second material is polypropylene. grafted with maleic anhydride.

[0013] According to a characteristic of the invention, the intercalary device comprises at least one main body formed by the internal body and the external layer, configured to be in contact with two rows of batteries, and at least one fluid connection pipe arranged at a longitudinal end of the main body, the fluid connection pipe being configured to allow the passage of a fluid.

[0014] It is thus possible to integrate the intercalary device into a cooling device of the electrical storage device, in particular with cooling tubes which have a shape similar to that of the body of the intercalary device intended to be sandwiched between the rows of batteries. In a context where the intercalary devices are arranged alternately within the rows of batteries with cooling tubes, the connecting pipe is intended to allow the passage of fluid from one cooling tube to the other, without the fluidic connecting pipe and the main body having any fluidic interaction, the main body of the intercalary device not being configured to allow the passage of a liquid within it.

[0015] According to a characteristic of the invention, the main body has a corrugated profile. Advantage is taken of such a characteristic in that it improves the retention of the batteries, particularly when the latter have a cylindrical shape. It is understood in particular that in such a configuration, each of the corrugations of the main body of the interposed device alternately accommodates one of the batteries of each of the two rows of batteries between which the interposed device is arranged.

[0016] The invention also relates to an electrical storage device comprising at least three rows of batteries, each of the rows of batteries extending along a longitudinal main elongation direction, the rows of batteries being aligned along a transverse direction secant to the longitudinal direction, the electrical storage device comprising at least one interposed device according to any of the preceding features extending longitudinally at least between two of the battery rows and at least one cooling device comprising at least one cooling circuit extending in the longitudinal direction between two battery rows and at least one fluid connector at a free end of the cooling circuit, the fluid connector and the cooling circuit being fluidically connected to each other.

[0017] It is understood that the cooling device ensures the cooling of the batteries by capturing their calories via a heat transfer fluid which circulates at least in the cooling circuit, also called a cooling tube.

[0018] According to a characteristic of the invention, the at least one interposed device and the at least one cooling device are arranged alternately between the rows of batteries, the fluid connector of the cooling device and the fluid connection pipe of the interposed device being fluidically connected to each other.

[0019] In other words, at least one row of batteries is arranged between the interposed device and the cooling device in the transverse direction. Thus, it is understood that the fluid connection between the fluid connector and the fluid connection pipe allows the heat transfer fluid to be conveyed from one cooling tube to the other despite the alternating arrangement of the interposed device and the cooling device between the rows of batteries.

[0020] According to a characteristic of the invention, the cooling device is made of aluminum. Such a material has in particular optimal thermal properties.

[0021] According to a characteristic of the invention, the cooling tube of the cooling device has a corrugated profile.

[0022] According to a characteristic of the invention, the undulations of the cooling tube of the cooling device and / or of the main body of the interposed device have a complementary shape with a cylindrical shape of the batteries.

[0023] The invention also relates to a method for manufacturing an interposed device according to any one of the preceding characteristics, the method implementing the first material, the second material and a mixing device comprising at least one inlet opening and a helical member arranged in an internal volume of the mixing device, the method comprising at least a first step during which the first material is mixed with the second material so as to obtain a mixture comprising at least 70% of the first material, at least a second step during which the mixture is introduced into the mixing device via the inlet opening and then the helical member is rotated so that it separates the first material and the second material so that the second material coats the first material.

[0024] According to a characteristic of the method, the mixing device comprises at least one outlet opening, preferably opposite its inlet opening, the method comprising at least a third step during which the mixture is expelled from the mixing device by the rotation of the helical member and in such a way as to obtain the main body of the interposed device at the outlet of the mixing member.

[0025] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0026] [Fig-1] is a schematic top view of an electrical storage device according to the invention;

[0027] [Fig.2] is a close-up view of the electrical storage device of [Fig.l] showing an alternating arrangement of an interposing device and a cooling device between rows of batteries;

[0028] [Fig.3] is a cross-sectional and longitudinal view of the interposing device of [Fig.2];

[0029] [Fig.4] is a longitudinal sectional view of a mixing device used in a method of manufacturing the interlayer device according to the invention.

[0030] The invention relates to an electrical storage device 1, visible in [Fig.l], capable in particular of equipping a motor vehicle with an electric or hybrid engine. Such an electrical storage system 1 is in particular intended to supply electrical energy to the motor vehicle for its movement.

[0031] To this end, the electrical storage device 1 comprises a plurality of batteries 2 ensuring the storage of electrical energy and arranged within a battery box 26. According to the example of the invention illustrated, the batteries 2 are here of cylindrical shape. More precisely, the batteries 2 are arranged in rows 4 of batteries 2 and in such a way that the electrical storage device 1 comprises at least three rows 4 of batteries 2. It should be considered that the electrical storage device 1 can comprise more than three rows 4 of batteries 2 but that the invention will be described in the remainder of the description with only three rows 4 of batteries 2, all of the characteristics described in relation to the rows 4 of batteries 2 applying mutatis mutandis to an indeterminate quantity of rows 4 of batteries 2.

[0032] According to the invention, each of the rows 4 of batteries 2 extends along a longitudinal direction of main elongation P L, the rows 4 of batteries 2 being arranged in parallel to each other along a transverse direction T secant to the longitudinal direction L. In order to operate optimally, the rows 4 of batteries 2 are at a distance from each other along the transverse direction T and the batteries 2 are spaced from each other along the longitudinal direction L within of the same row 4 of batteries 2. It is understood that such longitudinal spacing L and transverse spacing T between the batteries 2 limits the phenomena of overheating within the electrical storage device 1.

[0033] A bonding material 28 is injected into the battery box 26 and has the function of filling these different spaces and fixing the position of the batteries relative to each other.

[0034] According to the invention, the electrical storage device 1 comprises at least one interposed device 6 which extends longitudinally at least between two of the rows 4 of batteries 2. The interposed device 6 participates in particular in maintaining the two rows 4 of batteries 2 between them. Furthermore, the interposed device 6 has at least in part a corrugated profile, visible in [Fig. 2], in order to have a complementarity of shape with the cylindrical batteries 2, such a complementarity of shape ensuring the maintenance of the batteries 2 within the rows 4 of batteries 2. The interposed device 6 will be detailed in particular later in the rest of the description, in Figures 2 and 3.

[0035] In the illustrated example, the electrical storage device 1 comprises at least one cooling device 8, visible in Figures 1 and 2, which extends in the longitudinal direction L between two rows 4 of batteries 2. The cooling device 8 comprises at least one cooling circuit, or cooling tube, 10 which extends in the longitudinal direction L between two rows 4 of batteries 2, and at least one fluid connector 12 which extends at a free end 14 of the cooling circuit 10. It is understood that the cooling circuit 10 ensures the circulation of a heat transfer fluid between the batteries 2 of the two rows 4 of batteries 2 between which it extends, thus ensuring the cooling of the latter by capturing their calories.It is further understood that the fluid connector 12 ensures the routing of the heat transfer fluid to the cooling circuit 10 so that the latter captures the calories from the batteries in order to cool them. In other words, the fluid connector 12 and the cooling circuit 10 are fluidically connected to each other. The fluid connector 12 is also connected directly or indirectly to a heat transfer fluid storage tank, not visible here.

[0036] According to the example of the invention illustrated in [Fig. 2], and without this being limiting of the invention, the fluid connector 12 may comprise two circulation conduits 13, such that one of the circulation conduits corresponds to the inlet conduit of the heat transfer fluid into the cooling circuit, and the other corresponds to the outlet conduit of the heat transfer fluid from the cooling circuit.

[0037] The cooling tube, like the interposed device, may have a complementary shape with the shape of the batteries 8, and in particular have a profile corrugated so as to cooperate optimally with the cylindrical shape of the batteries 2.

[0038] According to a characteristic of the invention visible in Figures 1 and 2, the at least one interposed device 6 and the at least one cooling device 8 are arranged alternately between the rows 4 of batteries 2. It is understood in particular that the interposed device 6 and the cooling device 8 do not extend between two same rows 4 of batteries 2. More particularly, the interposed device 6 and the cooling device 8 are arranged alternately between the rows 4 of batteries 2 in the transverse direction T. Thus, it is understood that at least one row 4 of batteries 2 is arranged between the interposed device 6 and the cooling device 8 in the transverse direction T.

[0039] The cooling device 8 and the interposed device are distinguished from each other on the one hand by their internal structure, with the cooling device being able to be crossed by a cooling fluid while the tube is not, and on the other hand by the material from which they are composed.

[0040] The cooling device is made of a thermally conductive material, and in particular of aluminum, which also has an advantage in terms of weight.

[0041] The interposed device is itself made from a thermoplastic material, and in particular polypropylene, since the sole function of this interposed device is to create the desired spacing between two successive rows of batteries and it is desired to have an inexpensive material that is easy to conform.

[0042] The interposed device 6 will now be described in more detail using figures 2 and 3. It is also understood that only one interposed device 6 will be described in detail in the remainder of the description but that all of the characteristics described apply mutatis mutandis to a plurality of interposed devices 6 of the electrical storage device 1.

[0043] The interposed device 6 according to the invention extends mainly in the longitudinal direction L and comprises at least one main body 16 and a fluid connection pipe 18 arranged at a longitudinal end 20 of the main body 16.

[0044] The fluid connection pipe 18 is configured to allow the passage of a fluid, here the heat transfer fluid circulating in the cooling device 8, in particular to allow the passage of this fluid from one cooling device 8 to the other. As mentioned, the main body 16 of the intermediate device 6 is not configured for the passage of a fluid, so that the fixing of the fluid connection pipe 18 on the main body 16 does not require a fluid connection.

[0045] The fluid connection line 18 and the fluid connector 12 of the cooling device 8 are configured to be fluidically connected to each other. Thus, such fluid communication between the fluid connection pipe 18 and the fluid connector 12 ensures the delivery of heat transfer fluid to the cooling circuit 10 despite the alternating arrangement of the intermediate device 6 and the cooling device 8 between the rows 4 of batteries 2.

[0046] As visible in [Fig.2], the fluid connection pipe 18 may comprise two circulation channels 19 so as to cooperate with the circulation pipes 13 of the cooling device 8 as mentioned previously.

[0047] As can be seen schematically in [Fig. 3], the intercalary device 6 according to the invention comprises an internal body 22 covered with an external layer 24, the internal body 22 and the external layer 24 forming in particular the main body 16 mentioned above. In particular, the external layer 24 of the main body 16 surrounds the internal body so as to form the external surface of the main body, intended to be in contact with the two rows 4 of batteries 2 between which the intercalary device 6 is arranged and to be in contact with the bonding material 28 injected into the battery box.

[0048] According to a characteristic of the invention, the inner body 22 and the outer layer 24 are made respectively of a first material and a second material which is different from the first material. In particular, the two materials differ in their own surface tension, this different surface tension being able in particular to be obtained by an additive added to the polypropylene serving as the base material for the entire interlayer device.

[0049] More particularly, the second material, used to produce the external layer intended to be in contact with the bonding material 28, has a surface tension greater than a surface tension of the first material, used to produce the internal body. A high surface tension of the second material allows the latter to be able to chemically bond more easily with the bonding material, for example formed by epoxy resin.

[0050] Furthermore, the two materials used to produce the interlayer device differ in their viscosity rate. The first material, used to produce the inner body, has a first viscosity rate and the second material, used to produce the outer layer, has a second viscosity rate, the first viscosity rate being higher than the second viscosity rate.

[0051] Such a difference in viscosity between the first material and the second material is particularly advantageous in a method of manufacturing the intercalary device 6 according to the invention, to allow the second material to position itself covering the first material during the extrusion phase, such a method being detailed further on in the remainder of the detailed description.

[0052] Usually, as a non-limiting example, the fluidity of the grafted PP is gener- The flow rate is generally between 10g / 10 min and 80g / 10 min, while the flow rate of simple PP, known as "core" is generally between 10g / 10 min and 20g / 10 min. These values ​​are given in MFI. The MFI is a flow rate index, therefore comparable to a viscosity. The MFI represents the quantity of material that flows through a die, with a given weight and at a given temperature: it is expressed in g / 10 min.

[0053] The minimum gap between the two materials must be at least 15% to ensure demixing. The fluidity of the grafted PP must always be greater than the fluidity of the core PP.

[0054] In other words, the internal material must be more viscous and therefore have a low MFI, while the external material must be comparatively more fluid and therefore have a higher MFI.

[0055] According to a non-limiting example of the invention, the first material is polypropylene and the second material is polypropylene grafted with maleic anhydride. Furthermore, the fluid connection pipe 18 of the interposed device 6 may for example be made of polypropylene.

[0056] As mentioned above, the intercalary device 6 has at least in part a complementary shape with the batteries 2. More precisely, the main body 16 of the intercalary device 6 has a complementary shape with the batteries 2 and has for this purpose a corrugated profile. The nesting of the batteries 2 in the corrugations of the main body 16 of the intercalary device 6 makes it possible to improve the maintenance of said batteries 2 within the electrical storage device 1 in cooperation with the cooling device 8 described above. The previously mentioned arrangement of an internal body and an external layer, with different viscosity and surface tension properties, takes effect in particular over the entire longitudinal extent of the main body 16 of the intercalary device 6.

[0057] Advantage is taken of the intercalary device 6 as just described in that it makes it possible to improve the adhesion of the bonding material 28 to the main body 16 of the intercalary device 6, as visible in [Fig. 1]. The addition of an additive and in particular here maleic anhydride to the external surface of the main body 16, makes it possible to locally increase the surface density of the intercalary device and to promote the cooperation of the external layer with the bonding material.

[0058] More particularly, during the manufacture of the electrical storage device 1, the at least three rows 4 of batteries 2 are assembled with each other by means of the intercalary device 6 and the cooling device 8 as described previously, the assembly being arranged in the box 26 of battery 2, visible in [Fig.l], subsequently filled with the bonding material 28 so that it locks the different elements of the electrical storage device 1 in position. Thus, the particular composition of the main body 16 of the intercalary device 6 ensures a optimal adhesion of the bonding material 28 with said main body 16 and in particular with the external layer 24. This improves the maintenance of the intercalary device 6 within the electrical storage device 1, and thus the maintenance of the batteries.

[0059] A method of manufacturing the interposed device 6 will now be described in particular with reference to [Fig.4].

[0060] The manufacturing method according to the invention notably implements a mixing device 30 comprising at least one inlet opening 32 and one outlet opening 34 opposite its inlet opening 32 in a main elongation direction of the mixing device. The mixing device 30 further comprises an internal volume 36 delimited by a peripheral wall 38 in which the inlet 32 ​​and outlet 34 openings are formed. Thus, the inlet 32 ​​and outlet 34 openings ensure fluid communication between the internal volume 36 of the mixing device 30 with an environment external to the latter. The mixing device 30 further comprises a helical member 40 arranged in its internal volume 36, the helical member 40 extending substantially over the entire length of the mixing device 30 in its main elongation direction.

[0061] The method comprises at least a first step during which the first material is mixed with the second material so as to obtain a mixture 4L. The mixture 41 may in particular comprise at least 70% of the first material. In a second step, the mixture 41 obtained during the first step is introduced into the internal volume 36 of the mixing device 30, via the inlet opening 32, then the helical member 40 is rotated so that it separates the first material and the second material so that the second material coats the first material. Such a separation of the first material and the second material within the internal volume 36 of the mixing device 30 is in particular implemented by the difference in viscosity between these materials as mentioned previously.The second, less viscous material tends to move faster and come into contact with the internal surface of the peripheral wall, so that the first material, more viscous than the second material, is separated from this internal surface by the presence of the second material.

[0062] Once this stratification has been carried out between the first material and the second material, the method comprises at least a third step during which the mixture is expelled from the mixing device 30 by the rotation of the helical member 40 and in such a way as to obtain a matrix of the main body 16 of the interposed device 6 at the outlet of the mixing member 30 via the outlet opening 34. The main body can then be shaped to take the previously mentioned undulating shape.

[0063] The intercalary device is then obtained by carrying out at least one step additional, here fourth step, during which the fluid connection pipe 18 is secured to the longitudinal end 20 of the main body 16 obtained at the end of the first three steps of the method. The securing between the fluid connection pipe 18 and the main body 16 can in particular be carried out for example by brazing or by gluing, or by any other means ensuring a sealed connection between them.

[0064] As just described, the invention meets the aims it set itself, namely obtaining an intercalary device which allows good holding of a bonding material without it being necessary to produce this intercalary device in an expensive material.

[0065] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention, provided that an interposed device is formed at least in part from two different materials, with the covering material, intended to be in contact with a bonding material in a battery box, which has a surface tension greater than the average surface tension of the rest of the interposed device.

Claims

Claims

1. An interposed device (6) configured to extend between two rows (4) of batteries (2) of an electrical storage device (1), the interposed device (6) extending mainly in a longitudinal direction (L) and having at least one internal body (22) covered with an external layer (24), the internal body (22) and the external layer (24) being made respectively of a first material and a second material different from the first material, the second material having a surface tension greater than a surface tension of the first material, the first material being polypropylene and the second material being polypropylene grafted with maleic anhydride.

2. Intermediate device (6) according to the preceding claim, in which the first material comprises a first viscosity rate and the second material comprises a second viscosity rate, the first viscosity rate being higher than the second viscosity rate, preferably at least 15% higher, preferably 50%, preferably 100% higher than the second viscosity rate of the second material.

3. Intermediate device (6) according to any one of the preceding claims, comprising at least one main body (16) formed by the inner body (22) and the outer layer (24), configured to be in contact with two rows (4) of batteries (2), and at least one fluid connection pipe (18) arranged at a longitudinal end (20) of the main body (16), the fluid connection pipe (18) being configured to allow the passage of a fluid.

4. An electrical storage device (1) comprising at least three rows (4) of batteries (2), each of the rows (4) of batteries (2) extending in a longitudinal (L) main elongation direction (P), the rows (4) of batteries (2) being aligned along a transverse direction (T) intersecting the longitudinal direction (L), the electrical storage device (1) comprising at least one interposed device (6) according to any one of the preceding claims which extends longitudinally at least between two of the rows (4) of batteries (2) and at least one cooling device (8) comprising at least one cooling circuit (10) which extends in the longitudinal direction (L) between two rows (4) of batteries (2) and at least one fluid connector (12) at a free end (14) of the cooling circuit. dissement (10), the fluidic connector (12) and the cooling circuit (10) being fluidically connected to each other.

5. Electrical storage device (1) according to the preceding claim, wherein the at least one interposed device (6) and the at least one cooling device (8) are arranged alternately between the rows (4) of batteries (2) and wherein the fluid connector (12) of the cooling device (8) and the fluid connection line (18) of the interposed device (6) are fluidically connected to each other.

6. A method of manufacturing an interposed device (6) according to any one of claims 1 to 3, the method implementing the first material, the second material and a mixing device (30) comprising at least one inlet opening (32) and a helical member (40) arranged in an internal volume (36) of the mixing device (30), the method comprising at least a first step during which the first material is mixed with the second material so as to obtain a mixture (41) comprising at least 70% of the first material, at least a second step during which the mixture (41) is introduced into the mixing device (30) through the inlet opening (32) and then the helical member (40) is rotated so that it separates the first material and the second material so that the second material coats the first material.

7. Manufacturing method according to the preceding claim in combination with claim 3, wherein the mixing device (30) comprises at least one outlet opening (34), preferably opposite its inlet opening (32), the method comprising at least a third step during which the mixture is expelled from the mixing device (30) by the rotation of the helical member (40) and so as to obtain the main body (22) of the interposed device (6) at the outlet of the mixing member (30).

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