TECHNICAL FIELD This invention relates to vehicle batteries and, more specifically, to a device for actively cooling a vehicle battery under high temperature conditions.

BACKGROUND AND SUMMARY OF THE INVENTION In today's vehicles, underhood temperatures can and often do reach in excess of 200° F. A number of ways have been devised by automobile manufacturers to solve the problem of excessive underhood heat. One way is to re-locate the battery completely out of the engine compartment, into another cooler area of the vehicle. Another way is. to protect the battery with a passive, rigid thermoguard made out of polypropylene that is placed around the battery, allowing for some"dead air"space that helps insulte the battery. Another method is to place a "blanket"made from any suitable material such as foam or bubble packaging material, about the battery. While these solutions can offer some help, they offer only temporary solutions, especially in warm weather areas such as the southern United States.

The above described thermoguards generally provide some type of insulation materials, including dead air space, that have a sufficient"R" factor to help attenuate the heat. However, once a vehicle is in ambient

temperatures of 90° F. or more, and with stop-and-go driving that includes periods where the car will sit for 30 minutes or more, the battery can still reach extreme underhood temperatures.

Another way to reduce battery temperature is to use a thermoguard enclosure of the type described above, but that can also connect up to an opening in the front of the vehicle (for example, in the vehicle grille) where air can be introduced when the vehicle is moving.

However, the effectiveness of this technique is limited to periods when the vehicle is in substantial motion.

In order to protect a vehicle battery by preventing the latter from reaching fatal underhood temperatures, it is necessary to insure that the battery receives a continuous cooling air flow not only when in motion, but also when stationary and still hot.

In accordance with one exemplary embodiment of the invention, insulating air space is used in combination with a fan. Specifically, in one embodiment, a separate outer shell is provided for the battery. This outer shell preferably encloses the top and sides of the battery with an air space of approximately (but not limited to) about 0.25 inch between the shell and the battery casing. It should be understood that the shell may also enclose the bottom of the battery if so desired. Air flow is directed into the dead space between the shell and the battery through an opening in the shell which houses a fan that is connected to a tube or conduit that brings outside air (i. e., from outside the hood area) into the shell from any number of locations. Preferably, there is an exit port on the opposite side

of the shell to allow the cooling air flow to escape through a duct or tube, also preferably leading to an opening outside the engine compartment.

In this exemplary embodiment, the fan is one that operates on the vehicle system voltage and is of a low current draw, low noise design.

Such fans are readily available and the construction per se of the fan is not part of this invention. The fan may operate under the control of an existing engine controller, or through a separate mechanism such as a simple mechanical thermostat.

In an alternative embodiment, the outer shell may be incorporated into the battery construction by providing a double wall battery casing, the outer shell incorporating a fan in an inlet port to supply cooling air to the space between the inner and outer walls.

Accordingly, in its broader aspects, the present invention relates to an active thermal protection device for a vehicle battery comprising an outer shell including at least front, back and side walls closed at an upper end by a cover; an inlet port on one wall of the shell, in combination with a fan arranged to supply cooling air to the inlet port.

In another aspect, the invention relates to a combination vehicle battery and thermal protection device for the battery comprising an outer shell including at least front, back and side walls closed at an upper end by a cover; an inlet port on one wall of the shell; a fan located in proximity to the inlet port; and an outlet port located on a wall opposite the wall in which the inlet is located; wherein the battery is located within the shell and wherein space is maintained between the battery and the shell at

least about the front, back and side walls and the cover, the fan arranged to supply cooling air to the space.

Other objects and advantages of the subject invention will become apparent from the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a rear elevation of a battery shell in accordance with the subject invention; and FIGURE 2 is a side elevation of the battery shell shown in Figure 1, with the battery, inlet and outlet conduits added in phantom.

BEST MODE FOR CARRYING OUT THE INVENTION With reference to Figures 1 and 2, a battery enclosure or outer shell 10 in accordance with this invention includes a box-like component including sides 12 and front and back walls 14,16 and a top cover 18. In the illustrated embodiment, a bottom wall 20 is also provided although this is not a requirement. Of course, if bottom wall 20 is incorporated into the shell, then cover 18 is made removable to enable placement of the battery within the outer shell. The outer shell is sized to establish at least about 0.25 inch air space between the shell and the battery casing C (Figure 2). When a bottom wall 20 is included, internal ribs 21 maintain the desired space between the battery and the bottom wall. If no bottom wall is provided, the enclosure 10 can be slipped over the battery casing C, with internal ribs 21'maintaining the desired space between the cover

18 and battery casing C. The shell is preferably polypropylene but other suitable materials may be used.

The cover 18 includes a top wall 22 and a peripheral skirt 24. The cover may be removably secured to the shell body in any suitable fashion, but it is desirable that the cover engage the body in such a way as to substantially prevent any cooling air flow from escaping through the cover. As one example, snap fit flanges 23 may be used to secure the cover to the shell. Alternatively, the top cover 18 may be bonded or otherwise made integral with the walls 12,14 and 16, for those applications where no separate bottom wall is included.

The rear wall 16 of the shell is provided with an inlet port 26, fitted with a small fan 28 secured therein by any suitable means. The fan 28 is preferably an electric fan which operates off the vehicle current, and should be rated at no lower than 1.4 cfm. An exit port 30 is formed in the front wall 14 to allow the cooling air flow circulating through the shell between the interior walls of the shell and the battery itself, to escape, thus promoting continuous and effective cooling. A flexible tube or conduit 32 may be secured to the outlet port so as to direct the cooling air to an area remote from the battery, preferably outside the engine compartment. Similarly, a conduit or tube 34 may be secured to the enclosure inlet port 26 to direct cooling air flow to the fan. The inlet tube or conduit 34 preferably draws air from outside the engine compartment so that the cooling air is at a lower temperature than air typically found within the engine compartment, establishing a heat exchange environment wherein heat is carried away from the battery.

The fan 26 may be controlled by a conventional engine controller EC of an engine computer system, taking the underhood temperature as an input and governing the fan accordingly. Alternatively, the fan may be controlled by a simple mechanical thermostat. The idea is to maintain the battery within an acceptable temperature range, particularly when the vehicle is not in motion and when the engine is at idle or turned off but still hot. Thus, the fan 28 may also be arranged to operate within certain time intervals following the shut-off of the engine or, if thermostat controlled, whenever the temperature rises to a predetermined threshold value.

Various alternative arrangements are within the scope of the invention. For example, the outer shell 10 may be incorporated into the battery housing per se, in the form of a double wall battery casing construction about the side and bottom walls of the battery, in combination with a removable cover. Webs or ribs such as those at 21 and 36 would serve as integral connectors in the arrangement.

The fan 28 may be located not only in the inlet port 26, but also anywhere along the inlet conduit 34 (if used) to supply cooling air to the space between the battery and the shell (whether separate or integral).

Alternatively, the fan may be reversed and located in the outlet port 30 or outlet conduit 32 to draw cooling air through the enclosure in an opposite direction.

For geographic areas with lower average temperatures, or for vehicles with large enough underhood areas, it is also possible to omit the inlet and outlet conduits 32,34, with the fan 26 located directly within the inlet port 26 or outlet port 30.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.