GB2081495A

GB2081495A - Electrical energy storage and supply unit for electric vehicles

Info

Publication number: GB2081495A
Application number: GB8120958A
Authority: GB
Original assignee: Centro Ricerche Fiat SCpA
Current assignee: Centro Ricerche Fiat SCpA
Priority date: 1980-07-07
Filing date: 1981-07-07
Publication date: 1982-02-17
Also published as: DE3126594A1; FR2486311A1; FR2486311B1; IT8053367V0

Abstract

A number of batteries (14) are ridigly clamped together in two parallel spaced rows within a container (10), and spacing means (20, 44, 46) are interposed between the base and side walls of the container and the batteries, and between the two rows of batteries, to define ventilation passages communicating with apertures (38, 30) in the upper and lower parts of opposite end walls of the container. <IMAGE>

Description

SPECIFICATION Electrical energy storage and supply unit for electric vehicles The present invention relates to an electrical energy storage and supply unit for installation on electric vehicles, particularly electric road vehicles.

The object of the present invention is to provide a storage and supply unit which is particularly serviceable, safe and practical.

In order to achieve this object the present invention provides an electrical energy storage and supply unit for installation on electrical vehicles, the main characteristic of which lies in the fact that it comprises: -a rectangular container of electrically and thermally insulating material having a rapidly releasable cover; a rigid pack of batteries removably housed in the container; ~means clamping the batteries together in two parallel rows which are spread apart to define an intermediate, longitudinally-extend ing passage between them;; spacing means for maintaining the pack of batteries spaced from each wall of the container to define a series of intercommuni cating ventilation passages between the pack of batteries and the walls of the container, which ventilation passages also communicate with the said intermediate passage between the two rows of batteries and with the exterior of the container through respective ventilation apertures formed in lower and upper parts respectively of opposite walls of the container facing the ends of the two rows of batteries; electrical interconnecting means connect ing the electrical terminals of the batteries together in series, and electrical connection means carried by at least one of the walls of the casing and electrically connected to the said electrical interconnecting means of the batteries.

The batteries of the unit of the invention are thus electrically and thermally insulated from the external environment, allowing them to be kept warm in the winter months and to be cooled efficiently in the summer months due to the circulation of external air through the ventilation passages between the pack of bat teries and the walls of the container and between the two rows of batteries in the pack, preventing overheating. The air circulation also ensures efficient "washing" of the unit, .thus limiting the risk of explosion in the case of leakage from the batteries.

Thanks to the rigidity of the battery pack the function of the container is reduced exclu sively to one of insulation and separation of the batteries from the environment. Thus the container may be formed from a light and economic material, such as a plastics material, with walls of a very small thickness. Should a battery explode, the container is perfectly able, thanks to the air spaces between the walls and the pack of batteries, to contain the pressure wave and any parts of the batteries which may be detached by the explosion, avoiding damage.

According to a preferred characteristic of the invention, the unit further includes a filling and venting circuit comprising a plurality of ducts interconnecting filling manifolds of the batteries in series and a pair of tubular end connectors projecting out of the container.

This, on the one hand, results in a noticeable simplification of the operations required for maintaining the unit and, on the other hand, increases the safety during charging due to the conveyance of the explosive mixture which forms within the batteries to the exterior.

According to the invention, the clamping means for the pack of batteries preferably comprise a pair of transverse plates disposed one at each end of the two rows of batteries and a plurality of longitudinally-extending tie rods interconnecting the two plates and provided at their ends, which project outwardly of the plates, with screw means for clamping the two plates against the two rows of batteries.

These clamping means, as well as being extremely light and economical and able to ensure the necessary rigidity of the pack of batteries, are also used, to advantage, as spacer elements for maintaining the pack of batteries spaced from the walls of the container.

Further characteristics and advantages of the invention will become clear in the course of the detailed description which follows, with reference to the appended drawings provided purely by way of non-limiting example, in which: Figure 1 is an exploded perspective view of an electrical energy storage and supply unit according to the invention; Figure 2 is a longitudinal sectional view of the unit of Fig. 1; Figure 3 is a transverse sectional view taken on line Ill-Ill of Fig. 2; Figure 4 is a partially-sectioned view on an enlarged scale of a detail illustrated in Fig. 2, and Figure 5 is a longitudinal sectional view taken on line V-V of Fig. 3.

Referring to the drawings, and in particular to Fig. 1, the electrical energy storage and supply unit according to the invention comprises essentially a container 10 and a rigid pack 12 of ordinary batteries 14.

The container 10 is of an electrically and thermally insulating material, for example a glass-fibre reinforced plastics material, and is constituted by a lower part in the form of a rectangular tank 16 and a horizontal cover 18 releasably attached to the edge of the lower tank part 16. This lower tank part 16 has two longer, opposite, side walls 1 6 a, two shorter opposite side walls 1 6b and a base 1 6c having a series of longitudinal ridges 20 on its inner surface, as is clearly seen in Fig. 3.

The lower part 16 of the container 10 is further provided with a pair of transverse metallic reinforcing bands 22 which extend down the side walls 1 6a and across the base 16 c and terminate at the edge of the opening of the container 10. A metal lifting handle 24 is articulated to each of the two ends of each band 22 while an anchoring plate 26 is fixed to each band 22 close to the lower edge of the container 10 for fixing the device to a support structure (not illustrated) of a vehicle by means of screws.

The lower portion of one of the shorter side walls 1 6b of the lower tank part 16 has a series of slots 30 which put the interior of the container 10 into communication with the atmosphere. The same side wall 1 6b is also provided with a pair of female sockets 32, 34 and, in its upper part, with a pair of throughholes 36. The other short side wall 1 6b has a series of apertures 38, similar to the apertures 30, close to its upper edge.

The cover 18 is constituted by a rectangular plate with an outline complementary to that of the opening of the lower tank part 16 and having an annular gasket of elastomeric mate rial 40 around its edge to ensure the fluidtight sealing of the container 10. The fixing of the cover 18 to the lower tank part 16 is achieved by the engagement of the handles 24 in cooperating depressions 42 formed in the outer face of the cover 18. The handles 24 may be releasably retained in the depressions 42 by means of snap engageable catches not shown, or by any other suitable system.

The pack of batteries 12 is inserted in the container 10 and, in the example illustrated, comprises eight batteries 14 disposed in two rows of four batteries placed side by side. The number of batteries 14 may differ from that illustrated and may, for example, be between four and sixteen. Naturally, the dimensions of the container 10 must be suited to the number of the batteries 14.

As stated previously, the batteries 14 are of a conventional type and each has an outer casing of insulating material 1 4a, the walls of which converge slightly towards the base and have outer surfaces which are fretted or finned to facilitate cooling, and an upper filling manifold 1 4b. The rigid packing of the two rows of batteries 14 is achieved by means of clamping members which comprise a pair of transverse metal plates 44 disposed at the ends of the two rows of batteries 14 and a plurality of longitudinally-extending metal tie-rods 46 interconnecting the two end plates 44 and provided at their ends, which project outwardly of the plates 44, with screwclamping members for pressing the two plates 44 against the ends of the two rows of batteries 14.There are six longitudinal tie rods 46 disposed in three pairs located respectively one pair adjacent the outer side of each row of batteries 14 and one pair in the zone between the two rows. The tie-rods 46 of each pair extend horizontally and clos6*to the upper and lower edges of the pack 12 respectively. As illustrated in Fig. 3, the two outer pairs of tie-rods 46 also act as spacer elements to maintain the pack 12 spaced from the longer side walls 1 6a of the container 10, while the inner pair of tie-rods 46 serve as spacer elements for maintaining the two rows of batteries 14 of the pack 12 spaced from each other.The pack 12 is also spaced from the base 1 6c of the container 10 by means of the ridges 20 provided on the upper face of the base 16 c and is spaced from the shorter side walls 1 6b of the container 10 as a result of the particular shape of the two plates 44. Each of these plates 44 is in fact provided with a pair of stiffening ribs 44a disposed one at the level of the upper tie rods 46 and one at the level of the lower tie rods 46 of each pair of tie-rods respectively.

Each rib 44a of each plate 44 has three holes 44b aligned with the tie rods 46 through which the tie-rods 46 are passed on assemblage of the pack 12.

The clamping of the plates 44 against the pack 12 of batteries 14 is achieved, as stated previously, by scrnwclamping means carried by the ends of the tie-rods 46 and acting against the plates 44. These screw means may also be used for the attachment of handles 48 located in correspondence with the shorter side faces 1 6b of the container 10. Indeed, as illustrated in detail in Fig. 4, the end of each tie-rod 46, which passes through the respective plate 44 and terminates within the hole 44b of the corresponding rib 44a has an axial screw-threaded hole 50 in which the screw-threaded end of a screw 52 engages. The screw 52 acts against the end of a sleeve 54 fitted coaxially over the end of the tie-rod 46, and the opposite end of which bears against the plate 44. The head of the screw 52 may be located within the container 10 and may act directly on the sleeve 54. When a handle 48 is provided, as in the illustrated embodiment, a spacer bush 56 is interposed between the sleeve 54 and the corresponding, adjacent side wall 1 6b of the container 10. The screw 52 projects through aligned holes in the side wall 1 6b and the handle 48 and clamps the latter between the head of the screw 52 and thb outer face of the side wall 1 6b. Thus, when the device is moved by means of the handles 48, the tractive forces applied to these handles 48 are transmitted directly to the pack 12 without acting on the container 10.

Preferably the plates 44 and their stiffening ribs 44a are provided with a protective coat ing of an acid-resistant plastics material 58. In addition, two channel-section elements 60 are slidably fitted on to the stiffening ribs 44a of that plate 44 facing the shorter side wall 16b of the container 10 having the lower aper ,turves 30, with the base walls of the channel section elements 60 in contact with the inner face of the side wall 1 6 b.

The presence of the spacer means described above between the pack 12 inserted in the container 10 and the walls of this container 10 results in the formation of a plurality of peripheral ventilation passages 62 communi cating with each other and with the central longitudinal passage 64 resulting from the presence of the pair of intermediate tie-rods 46 between the two rows of batteries 14 of the pack 12. Thus the pack 12 is separated from the casing 10 by an air space which ensures the thermal isolation of the pack 12 from the external environment, keeping the batteries warm in the winter months. In the summer months, and during charging of the batteries 14, this space allows a flow of cooling air to be conveyed and distributed along the surfaces of the batteries 14.The cooling air can in fact enter the lower part of the container 10 through the apertures 30, circulate within the passages 62 and 64 so as to flow over the surfaces of the batteries 14 and leave the container through the apertures 38. The circulation of the cooling air may be free or may be forced by arranging a suction device, not illustrated, in correspondence with the apertures 38. The channel-section ele ments 60 associated with the plates 44 adja cent the wall 16b provided with the apertures 30 prevent the air from rising directly to the upper part of the container 10 without first flowing over the surfaces of the batteries 14, the correct distribution of the cooling flow being further ensured by the constrictions in the areas of contact of the tie-rods 46 with the fretted or finned side walls of the batteries 14.

Since, as stated above, the batteries 14 normally have side walls which converge to wards their bases, the clamping and spacing means for the pack 12 further includes a plurality of transverse, trapezoidal-section, spacer plates 66 coated with a material with a high coefficient of friction and each interposed between one battery 14 and the adjacent ,battery 14 in the same row. Thus the pack 12 Sis perfectly rigid and the container 10 acts exclusively to insulate the batteries 14 ther mally and electrically from the external envi ronment. Any handling and moving of the container 10 may conveniently be carried out using the handles 24 or the handles 48. The handles 24 may also to advantage be used for lifting the device by servicing equipment, not shown in the drawings, which is able to engage the four handles 24 simultaneously.

The batteries 14 of the pack 12 are connected electrically in series with each other by means of a plurality of conducting bars 68.

Each conducting bar 68 is soldered to the corresponding electrical connecting terminals of two adjacent batteries 14 and is shaped so as to allow it to absorb limited relative displacements of these batteries 14. Each bar 68, which is preferably of copper coated with an acid-resistant plastics material, in fact comprises two longitudinally-extending sections 68a interconnected by an intermediate transverse section 68b so as to allow limited elongation of the bar 68. The ends of each bar 68 and the corresponding connecting terminals of the batteries 14 are preferably coated with lead to prevent the exposure of bimetallic couples to the acid of the batteries 14.

The two batteries 14 of each row which are located adjacent the side wall 1 6b of the container 10 provided with the sockets 32 and 34 are electrically connected to these sockets 32 and 34, for example by means of flexible cables. The two sockets 32 and 34, which as stated above are of the female type, allow the electrical connection to a load by means of connecting pins, eliminating any risk of accidental contact and current leaks.

The unit according to the invention further includes a filling and venting circuit, indicated in its entirety by 70 in Fig. 5. This system includes a series of connecting ducts 72 which interconnect the filling manifolds 1 4a of the batteries 14 in series. The circuit 70 further includes a pair of tubular connectors, that is, an inlet connector 74 and an outlet connector 76, fitted into the holes 36 of the container 10 and each provided with a manually operable stop cock 78. The circuit 70 may, to advantage, be used for filling the batteries with the electrolyte but also has the function of conveying the explosive mixture which forms within the batteries 14 to the exterior. This explosive mixture may be discharged to the exterior and dispersed through a flame trap of conventional type, not shown in the drawings.

From the above description it is clear that the mechanical strength of the device according to the invention is such as to allow it to be fixed to a support structure of an electric vehicle without any risk of detachment in the case of a collision or overturning of the vehicle. Furthermore, the container 10 is so formed as to contain at least some spillage of electrolytic liquid from the batteries 14 in the event of rupture or bursting of the batteries.

Should the batteries burst, the air space between the pack 12 and the walls of the container 10 enables the container 10 to contain the pressure wave, and any parts of the batteries 14 which may become detached due to the effect of the explosion, without risk of damage. The risk of explosion are, in any case, very small both because the explosive mixture which forms within the batteries 14 can be discharged to the exterior through the filling and venting circuit 70 and because the ventilation of the batteries 14 through the inlet apertures 30, the passages 62 and 64 and the outlet apertures 38 "washes" the space within the container 10 effectively.

Claims

1. An electrical energy storage and supply unit for installation in electric vehicles, comprising: a rectangular container of electrically and thermally insulating material having a rapidly releasable cover; a rigid pack of batteries removably housed in the container; means clamping the batteries together in two parallel rows which are spaced apart to define an intermediate, longitudinally-extending passage between them;; ~spacing means for maintaining the pack of batteries spaced from each wall of the container to define a series of intercommunicating ventilation passages between the pack of batteries and the walls of the container, which ventilation passages also communicate with the said intermediate passage between the two rows of batteries and with the exterior of the container through respective ventilation apertures formed in lower and upper parts respectively of opposite walls of the container facing the ends of the two rows of batteries; electrical interconnecting means connecting the electrical terminals of the batteries together in series, and ~electrical connection means carried by at least one of the walls of the casing and electrically connected to the said electrical interconnecting means of the batteries.

2. Unit according to Claim 1, in which each battery has a filling and venting manifold, and in which the unit further comprises a filling and venting hydraulic circuit including a plurality of ducts interconnecting the said manifolds of the batteries in series and a pair of tubular connectors projecting out of the container.

3. A unit as claimed in Claim 2, in which each of said tubular connectors includes a respective manually operable shutsff valve.

4. A unit as claimed in Claim 1, in which the container is provided with a pair of spaced-apart reinforcing bands extending around the base and side walls of the container transversely to the rows of batteries and terminating at the upper edge of the container, and in which respective pairs of lifting handles for the unit are articulated to the upper ends of said bands.

5. A unit as claimed in Claim 1, in which the cover of the container has an annular sealing gasket around its edge arranged to bear on the upper edge of the lower part of the container.

6. A unit as claimed in Claim 4, in which the cover of the container has in its outer surface respective depressions in positions corresponding to the respective lifting handles, the depressions being such as to accommodate the said lifting handles when the latter are lowered and not in use, retuning means being provided for retaining each Lifting handle in the associated depression of the cover.

7. A unit as claimed in any of Claims 1 to 6, in which the clamping means for the pack of batteries includes a pair of transverse plates disposed at the ends of the two rows of batteries and a plurality of longitudinal tie bars interconnecting the two plates and provided at their ends, projecting outwardly of the plates, with screw means for clamping the two plates against the two rows of batteries.

8. A unit as claimed in Claim 7, in which the longitudinal tie bars are disposed in three series of which two are adjacent the outer sides of the two rows of batteries and one is disposed in the said intermediate longitudinal passage between the two rows of batteries.

9. A unit as claimed in Claim 8, in which each series of tie bars includes two tie bars extending close to the upper edge and to the lower edge of the pack of batteries respectively.

10. A unit as claimed in Claim 8, in which the spacing means for maintaining the pack of batteries spaced from the walls of the container include: an undulating inner surface of the bottom wall of the container; the tie bars of the two series of tie bars adjacent the outer sides of the two rows of batteries, and a pair of spaced apart transverse projections carried by the outer faces of the end plates of the said clamping means and within which the ends of the said longitudinal tie bars are accommodated.

11. A unit as claimed in Claim 1, in which a spacer element having a surface with a high coefficient of friction is interposed between each battery and the adjacent battery of the same row of batteries.

12. A unit as claimed in Claim 7, and further including a pair of lateral carrying handles disposed on the walls of the container facing the ends of the two rows of the pack of batteries, the said handles being fixed directly to the ends of the longitudinal tie bars of the said clamping means.

13. A unit as claimed in any one of thb preceding claims, in which the said electrical interconnecting means are constituted by conductive bars welded to electrical terminals of the batteries and formed so as to allow them to absorb limited relative displacement of the batteries.

14. A unit as claimed in Claim 13. in which the said conductive bars are of copper coated with a resinous acid-resistant material.

15. A unit as claimed in any one of the preceding claims, in which the electrical connection means carried by at least one of the walls of the container are constituted by a pair of female sockets.

16. A unit as claimed in any one of the preceding claims, in which the container is provided with bottom anchoring plates for fixing it to an electric vehicle.

17. A unit as claimed in any one of the preceding claims, in which the container is fabricated in plastics material.

18. A unit as claimed in any one of the preceding claims, in which there are between four and sixteen batteries in the pack of batteries.

19. An electrical energy storage and supply unit substantially as herein described with reference to and as shown in the accompanying drawings.