AUTOMOBILE TRACTION BATTERY WITH COOLING WATER INLET MARKINGS

Abstract

A traction battery for an electric or hybrid motor vehicle, comprising a closed container holding electrochemical cells (30), and openings on this container for injecting cooling water, the container having specific external shapes (16) marking the openings intended to be drilled, each opening being positioned opposite an internal area of ​​this container (34) that is free of electrochemical cells (30). Figure 2

Description

Title of the invention: MOTOR VEHICLE TRACTION BATTERY WITH COOLING WATER INLET MARKINGS

[0001] The present invention relates to a traction battery for an electric or hybrid motor vehicle having markings in the tray for a cooling water inlet, as well as a motor vehicle equipped with such a battery and a method for working on the battery of this vehicle.

[0002] A known type of motor vehicle traction battery, presented in particular by document FR-A1-3105598, includes a sealed container equipped with sealing devices closing perforations, allowing rapid opening to inject cooling water in the event of an accident.

[0003] In the event of abnormal heating of the battery's electrochemical cells, following cell failure due to thermal runaway, or an accident resulting in a shock to the battery that damages cells, a fire may ignite in the chemical materials and spread to the other cells. In this case, a significant supply of water is required to cool the cells in order to prevent combustion or to extinguish a small fire.

[0004] In particular, lithium-ion electrochemical cells, having a high electrical energy storage density, can easily catch fire in the event of internal heating or accidental deformation.

[0005] The battery type shown includes devices for sealing the holes in the tray, comprising a cover bonded to each hole by an adhesive that loses its mechanical holding properties upon a significant temperature increase, which automatically detaches the cover. A sealing means is provided behind each sealing device.

[0006] The firefighters can then intervene with a fire hose by applying its nozzle into one of the passages opened by removing the cover, to pierce the sealing means arranged behind in order to inject water and flood the battery tray which otherwise remains closed.

[0007] However, this type of battery opening device is complex to produce, requiring for each drilling the installation of two successive barriers, the internal sealing means and then the detachable cover.

[0008] Furthermore, the internal sealing means must withstand high temperatures to prevent, in the event of a fire, the loss of all seals due to heat. which would open the tank too wide, making it a sieve that does not retain water, without effectively achieving the necessary flooding of the electrochemical cells.

[0009] The present invention is specifically intended to avoid these problems of the prior art.

[0010] To this end, it proposes an electric motor vehicle traction battery or hybrid, comprising a closed tank containing electrochemical cells, and on this tank opening locations allowing the injection of cooling water, this battery being remarkable in that the tank has particular external shapes constituting a marking designating the opening locations intended to be drilled, each opening location being arranged opposite an internal area of ​​this tank which is free of electrochemical cells.

[0011] One advantage of this traction battery is that by simply making the markings of the opening locations intended for drilling, for example with a particular shape of a sheet made by stamping, it is then possible in the event of abnormal heating of the battery for an operator who spots these markings to drill the tray precisely at one of these locations with a drilling tool.

[0012] The drilling tool and the nozzle of the fire hose are then introduced into the bore, opening into the inner area free of electrochemical cells, which avoids any contact with the cells which could damage them, again leading to risks of heating and fire.

[0013] Economically, with a simple external marking of the container which can be done economically, it is possible to secure both the electrochemical cells of the battery and the operators who work on the vehicle.

[0014] The traction battery according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0015] Advantageously, the external marking shape has a hollow turned towards the inside of the tray forming the opening location.

[0016] In this case, advantageously the hollow of the outer shape has a conical contour for centering a drilling tool.

[0017] Advantageously, each external marking shape includes around the hollow an indication enabling an operator to identify the opening location.

[0018] Advantageously, the external marking shapes are made by stamping a sheet of metal from the bottom of the tray that comes under the vehicle.

[0019] Advantageously, the free interior areas of the tank are arranged between the electrochemical cells and profiles forming the sides of this tank.

[0020] Advantageously, the battery comprises internal volumes separated by transverse ribs, each receiving electrochemical cells, each internal volume having an external marking shape.

[0021] The invention also relates to a motor vehicle equipped with a traction battery comprising any one of the preceding characteristics, notable in that the external marking shapes are arranged under the vehicle.

[0022] The invention also relates to a method of intervention on a vehicle comprising such a battery, remarkable in that in the event of a problem on the battery it successively comprises a step of locating an external shape of marking, drilling the opening location designated by this external shape, and then injecting water into the battery through this drilling.

[0023] The method may further include a step of drilling a second opening location away from the first location, allowing the water injected into the battery to exit.

[0024] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0025] [Fig-1] is a top view of a lateral half of a battery according to the invention presented without the lid;

[0026] [Fig.2] is a vertical cross-sectional view along the transverse direction of the vehicle of this battery passing through the axis of an opening location; and

[0027] [Fig.3] is a detailed view of this location after it has been drilled.

[0028] Throughout the document the upper or top direction is relative to a vehicle placed on a horizontal surface.

[0029] Fig. 1 presents a traction battery comprising a closed tray including a bottom 2 formed by a sheet metal, lateral profiles on the sides 4 having fixing holes 6 under the longitudinal members of the vehicle body, and transverse stiffening ribs 8 which delimit between each other internal volumes 10 having a surface 18 receiving the electrochemical cells.

[0030] The front of the battery receives electrical equipment 12 necessary for its control and power supply, which are connected to the vehicle's powertrain to supply it with electrical energy.

[0031] The lateral edge of the bottom plate 2 has in each internal volume 10, between the surface of the cells 18 and the lateral profile 4, a particular external marking shape comprising a hollow 16 visible from the underside of the vehicle, constituting both a reference for drilling the bottom and an aid for centering a drilling tool.

[0032] Figure 2 shows the battery tray comprising the base 2 having a contour forming a flat rim 20 slightly offset in height, which is screwed with a seal under the lateral profiles of the sides 4 formed from an extruded aluminum alloy, and a battery cover 22 formed from a sheet metal which closes the internal volume of the battery. A passenger compartment floor 24, fixed to the side rails of the vehicle 26, covers the battery.

[0033] The internal volumes 10 receive the electrochemical cells 30 arranged upright, which are fixed on a circulation panel of a cooling fluid 32.

[0034] Following the transverse direction of the vehicle, the electrochemical cells 30 are arranged at a distance D from the inner face of the side profiles 4, which constitutes a space free of critical element 34 which can heat up and ignite with major risks.

[0035] The bottom sheet metal 2 has in each internal volume 10, below the free space 34 and next to the flat rim 20, a hollow 16 formed by a stamping of the sheet metal turned towards the inside of the container, having a flat bottom and a conical contour which narrows towards the bottom.

[0036] In addition, the bottom plate 42 may have a specific indication around the hollow 16, including for example arrows directed towards it or concentric circles, formed by stamping the plate, or a color marking, which helps an operator to quickly identify the drilling area.

[0037] Figure 3 shows the tip 42 of a cylindrical tool 40 disposed in the hollow 16, held on the flat bottom of this hollow by its conical contour forming a guide, which is pressed firmly against the sheet metal to create a perforation, then its cylindrical part is advanced to form a hole of the same diameter. The drilling force can be applied, in particular, by the impact of a mass, or by a mechanical or hydraulic jack.

[0038] Advantageously the conical contour of the hollow 16 has a half-cone angle between 30° and 60° to facilitate the guidance of the point 42 in this hollow, which in this example is 45°.

[0039] After centering the tip of the tool 42 in the hollow 16 and drilling the sheet metal, the advance of the tool 40 occurs in the free space of the critical element 34, without risk of damaging an electrochemical cell 30. Then the nozzle of a fire hose can enter deep inside the battery tray in the free space 34, which holds it in the hole more easily to ensure that all the water discharged enters inside.

[0040] In addition, the operator can make a second hole far from the first, in particular opposite the battery, using another hollow 16 so as to make a circulation of the water exiting through this second hole to cross all the electrochemical cells 30.

[0041] It should be noted that the hollows 16 and the specific markings around these hollows formed by stamping the base plate 2 do not increase the cost of production of this sheet metal. Markings represent an effective and economical way to improve fire protection and safety.

Claims

Demands

1. Traction battery for an electric or hybrid motor vehicle, comprising a closed container holding electrochemical cells (30), and on this container opening locations for injecting cooling water, characterized in that the container has particular external shapes (16) constituting a marking designating the opening locations intended to be drilled, each opening location being arranged opposite an internal area of ​​this container (34) which is free of electrochemical cells (30).

2. Traction battery according to claim 1, characterized in that the external marking shape (16) has a hollow turned towards the inside of the tray forming the opening location.

3. Traction battery according to claim 2, characterized in that the hollow of the outer marking shape (16) has a conical contour for centering a drilling tool (40).

4. Traction battery according to claim 2 or 3, characterized in that each external form of marking (16) has around the hollow an indication enabling an operator to identify the opening location.

5. Traction battery according to any one of the preceding claims, characterized in that the external marking shapes (16) are made on a sheet of the bottom of the tray (2) coming under the vehicle.

6. Traction battery according to any one of the preceding claims, characterized in that the internal free areas of the tray (34) are arranged between the electrochemical cells (30) and side profiles of this tray (4).

7. Traction battery according to any one of the preceding claims, characterized in that it comprises internal volumes (10) separated by transverse ribs (8), each receiving electrochemical cells (2), each internal volume (10) having an external marking shape (16).

8. Motor vehicle equipped with a traction battery according to any one of the preceding claims, characterized in that the external marking shapes (16) are arranged under the vehicle.

9. A method of intervention on a vehicle according to claim 8, characterized in that in the event of a problem on the battery it successively comprises a step of locating an external shape of marking (16), drilling the designated opening location, and then injecting water into the battery through this drilling.

10. Intervention method according to claim 9, characterized in that it comprises a step of drilling a second opening location away from the first location, allowing the water injected into the battery to exit.

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