Vehicle battery fluid supply system with vacuum source

A system for supplying fluid to a battery, a vacuum source, a vehicle, a combination, a method for supplying fluid to a battery and a method of charging a battery. The fluid supply system supplies fluid to a battery in a vehicle, the vehicle including a frame supporting the battery, the battery including a battery cell, fluid being transmittable to the battery cell. The system is defined as including a hydraulic circuit connecting the battery to a tank. The hydraulic circuit is defined as including an inlet conduit connectable to tank, an outlet conduit connectable to the battery cell, and a vacuum source connectable to the battery cell and to the tank. The vacuum source is defined as including a pump having a pump inlet conduit connectable to the tank, and a pump outlet, and a venturi having a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet is connectable to the tank. The pump is operable to cause flow through the venturi, flow through the venturi causing fluid flow from the tank and through the battery cell.

FIELD OF THE INVENTION

The present invention relates to liquid electrolytic batteries and, more particularly, to a fluid supply system for adding water to the liquid electrolyte in the batteries.

BACKGROUND OF THE INVENTION

Battery-powered vehicles, such as, for example, golf carts and utility vehicles, require periodic charging of the batteries and replenishment of liquid electrolyte in the batteries.

SUMMARY OF THE INVENTION

One independent problem with existing filling devices and procedures is that a separate fluid hook-up step is required before the liquid electrolyte can be replenished in the batteries.

Another independent problem with existing filling systems and procedures is that, each time the batteries are replenished with fluid, a separate fluid source must be connected to the filling system, and fluid must be replenished, even if only a small amount of fluid must be replenished.

Yet another independent problem with existing filling systems and procedures is that a separate source of pressure is required to supply fluid to the filling system. Such a separate pressurized source may be a pump or a vacuum connected to the filling system.

A further independent problem with existing filling systems and procedures is that, if a vacuum source is used to cause fluid flow through the batteries, the vacuum source may draw battery gas from the batteries and may return the battery gas to the source of fluid or tank. The battery gas may then be vented when an operator accesses the tank.

An independent problem with a venturi is that, if the venturi is above the fluid level in a fluid system, the venturi will not produce the necessary suction to cause fluid flow in the system.

The present invention provides a system for supplying fluid to a battery, a vehicle and a method for supplying fluid to a battery which substantially alleviate one or more of the above-described and other problems with existing filling systems and procedures. More particularly, in some aspects, the present invention provides a fluid supply system in which fluid flow through a venturi supported on the vehicle frame creates a vacuum which causes fluid flow through the battery. In some aspects, the present invention provides a fluid supply system including a vacuum source to cause fluid flow through the battery and a gas separator to separate battery gas from the fluid flowing from the battery. In some aspects, the present invention provides a fluid supply system including a venturi for creating a vacuum to cause fluid flow through the battery and a muzzle for collecting fluid to submerge the venturi outlet.

In particular, the present invention provides a system for supplying fluid to a battery, the battery including a battery cell, fluid being transmittable to the battery cell. The system is defined as comprising a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, and an outlet conduit connectable to the battery cell, and a vacuum source connectable to the battery cell and to the tank. The vacuum source is defined as including a pump having a pump inlet connectable to the tank and a pump outlet, a venturi having a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet, and a muzzle connectable to the venturi outlet, fluid being collectable in the muzzle to submerge the venturi outlet, the pump being operable to cause flow through the venturi, flow through the venturi causing fluid flow from the tank, through the battery cell, and from the venturi outlet.

In some constructions, the system may further comprise a gas separator connectable to the battery cell, fluid and gas from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator. Preferably, the muzzle collects an amount of fluid sufficient to create a vacuum at the second inlet. The muzzle may include at least one opening allowing fluid flow from the venturi outlet. The venturi outlet has a cross-sectional outlet area, and the at least one opening has a cross-sectional opening area, the opening area preferably being greater than the outlet area. Preferably, the muzzle provides a seal at the connection to the venturi outlet. The muzzle is preferably connectable between the venturi outlet and the tank so that fluid flows from the venturi outlet to the tank.

Also, the present invention provides a system for supplying fluid to a battery in a vehicle, the vehicle including a frame supporting the battery, the battery including a battery cell, fluid being transmittable to the battery cell. The system is defined as comprising a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, and an outlet conduit connectable to the battery cell, and a vacuum source connectable between the battery cell and the tank. The vacuum source is defined as including a pump having a pump inlet connectable to the tank and a pump outlet, and a venturi supported on the vehicle, the venturi having a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet, the pump being operable to cause flow through the venturi, flow through the venturi causing fluid flow from the tank, through the battery cell, and from the venturi outlet.

In some constructions, the system may further comprise a gas separator connectable to the battery cell, fluid and gas from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator. Also, the vacuum source may include a muzzle connectable between the venturi outlet and the tank, fluid being collectable in the muzzle to submerge the venturi outlet.

In addition, the present invention provides a system for supplying fluid to a battery, the system comprising a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, an outlet conduit connectable to the battery cell, a vacuum source connectable to the battery cell and to the tank, the vacuum source being operable to cause fluid flow from the tank and through the battery cell, and a gas separator connectable to the battery cell, fluid and gas from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator.

Preferably, the gas separator includes a vent, the separated gas being vented through the vent. The battery cell has an air space having a size, and the gas separator preferably has a size substantially equal to the size of the air space. The gas separator is preferably connectable to the tank, fluid being transferable between the gas separator and the tank. The vacuum source has an inlet, and the vacuum source inlet may be connectable to the gas separator.

In some constructions, the vacuum source includes a pump having a pump inlet conduit connectable to the gas separator, and a pump outlet, and a venturi supported on the vehicle, the venturi having a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet connectable to the gas separator, the pump being operable to cause flow through the venturi, flow through the venturi causing fluid flow through the battery cell and from the venturi outlet to the gas separator. The vacuum source may include a muzzle connectable between the venturi outlet and the tank, fluid being collectable in the muzzle to submerge the venturi outlet.

Further, the present invention provides a vacuum source for supplying fluid from a tank to a battery, the battery including a battery cell, fluid being transmittable to the battery cell. The vacuum source is defined as comprising a pump connectable to the tank, a venturi including a nozzle connectable to the pump, the nozzle discharging fluid received from the pump, a suction inlet connectable to the battery cell, and a discharge outlet, and a muzzle connectable to the discharge outlet, fluid being collectable in the muzzle to submerge the discharge outlet, the pump being operable to cause fluid flow through the venturi, fluid flow through the venturi causing suction at the suction inlet, the suction causing fluid flow through the battery cell and from the battery cell through the suction inlet.

Also, the present invention provides a vacuum source for supplying fluid from a tank to a battery in a vehicle, the vehicle including a frame supporting the battery, the battery including a battery cell, fluid being transmittable to the battery cell. The vacuum source is defined as comprising a pump connectable to the tank, and a venturi supported on the frame. The venturi is defined as including a nozzle connectable to the pump, the nozzle discharging fluid received from the pump, a suction inlet connectable to the battery cell, and a discharge outlet, the pump being operable to cause fluid flow through the venturi, fluid flow through the venturi causing suction at the suction inlet, the suction causing fluid flow through the battery cell and from the battery cell through the suction inlet.

In addition, the present invention provides a vehicle comprising a frame supported for movement over ground, a motor supported by the frame and operable to selectively drive the vehicle, a battery supported by the frame and electrically connectable with the motor, the battery including a battery cell, fluid being transmittable to the battery cell, and a hydraulic circuit connecting the battery to a tank for holding fluid. The hydraulic circuit is defined as including an inlet conduit connectable to the tank, an outlet conduit connectable to the battery cell, and a vacuum source supported on the frame. The vacuum source is defined as including a pump having a pump inlet connectable to the tank and a pump outlet, and a venturi having a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet, the pump being operable to cause flow through the venturi, flow through the venturi causing fluid flow from the tank and through the battery cell.

In some constructions, the vehicle may be a golf cart. Also, the tank may be supported on the frame. The tank may have a first outlet for supplying fluid to the vacuum source, an inlet for receiving fluid from the vacuum source, and a second outlet for supplying fluid to the battery cell.

In some constructions, the vehicle may further comprise a gas separator connectable to the battery cell, gas and fluid from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator. In some constructions, the vacuum source may include a muzzle connectable to the venturi outlet, fluid being collectable in the muzzle to submerge the venturi outlet.

The vehicle may further comprise a second battery supported by the frame and electrically connectable with the motor, the second battery including a second battery cell, fluid being transmittable to the second battery cell. The pump may be operable to cause flow through the venturi, flow through the venturi causing fluid flow from the tank and through the first battery cell and through the second battery cell.

The vehicle may further comprise a controller connectable to the pump for controlling fluid replenishment to the battery. The controller may activate the pump when the fluid level is low in the battery cell to cause fluid flow from the tank to the battery cell. Preferably, the battery is connectable with the motor to selectively power the motor.

Further, the present invention provides a combination comprising a vehicle and a system for supplying fluid to the battery. The system is defined as including a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, an outlet conduit connectable to the battery cell, and a vacuum source. The vacuum source is defined as including a pump having a pump inlet connectable to the tank and a pump outlet, a venturi having a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet, and a muzzle connectable to the venturi outlet, fluid being collectable in the muzzle to submerge the venturi outlet, the pump being operable to cause flow through the venturi, flow through the venturi causing fluid flow from the tank, through the battery cell, and from the venturi outlet.

In some constructions, the vacuum source may be supported on the frame. Also, the hydraulic circuit may be supported on the frame. In addition, the tank may be supported on the frame. In some constructions, the combination may further comprise a gas separator connectable to the battery cell, gas and fluid from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator.

Also, the present invention provides a combination comprising a vehicle and a system for supplying fluid to the battery. The system is defined as including a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, an outlet conduit connectable to the battery cell, a vacuum source connectable to the battery cell and to the tank, the vacuum source being operable to cause fluid flow from the tank and through the battery cell, and a gas separator connectable to the battery cell, fluid and gas from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator.

In addition, the present invention provides a combination for supplying fluid to a battery, the battery including a battery cell, fluid being transmittable to the battery cell. The combination is defined as comprising a vacuum source connectable to the battery cell and to a tank for holding fluid, the vacuum source being operable to cause fluid flow from the tank and through the battery cell, and a gas separator connectable to the battery cell, fluid and gas from the battery cell flowing into the gas separator, the gas being separated from the fluid in the gas separator.

Further, the present invention provides a method for supplying fluid to a battery, the battery including a battery cell, fluid being transmittable to the battery cell. The method is defined as comprising the acts of providing a system for supplying fluid to the battery, the system including a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, an outlet conduit connectable to the battery cell, and a vacuum source connectable between the battery cell and the tank, the vacuum source including a pump including a pump inlet connectable to the tank and a pump outlet, a venturi including a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet, a muzzle connectable to the venturi outlet, collecting fluid in the muzzle to submerge the venturi outlet, and operating the pump to cause fluid flow through the venturi, flow through the venturi causing fluid flow from the tank and through the battery cell.

The providing act may include providing a gas separator connectable to the battery cell, wherein the operating act includes causing fluid and gas to flow from the battery cell to the gas separator, and the method may further comprise the act of separating the gas from the fluid in the gas separator.

Also, the present invention provides a method for charging a battery, the battery including a battery cell, fluid being transmittable to the battery cell. The method is defined as comprising the acts of providing a system for supplying fluid to the battery, the system including a hydraulic circuit connecting the battery to a tank for holding fluid, the hydraulic circuit including an inlet conduit connectable to the tank, an outlet conduit connectable to the battery cell, and a vacuum source connectable between the battery cell and the tank, the vacuum source including a pump including a pump inlet connectable to the tank and a pump outlet, a venturi including a first inlet connectable to the pump outlet, a second inlet connectable to the battery cell, and a venturi outlet, a muzzle connectable to the venturi outlet, collecting fluid in the muzzle to submerge the venturi outlet, charging the battery, operating the pump to cause fluid flow through the venturi, flow through the venturi causing fluid flow from the tank and through the battery cell, ceasing operation of the pump to stop fluid flow through the battery cell, continuing to charge the battery, and ceasing charging of the battery.

The providing act may include providing a gas separator connectable to the battery cell, wherein the operating act includes causing fluid and gas to flow from the battery cell to the gas separator, and the method may further comprise the act of separating the gas from the fluid in the gas separator.

One independent advantage of the present invention is that, is some aspects and in some constructions, the fluid source is supported on the vehicle. Therefore, a separate fluid hook-up step is not required before the liquid electrolyte can be replenished in the batteries.

Another independent advantage of the present invention is that, in some aspects and in some constructions, the fluid supply system automatically replenishes the necessary fluid to the batteries when necessary and each time the batteries are to be replenished. The operator is only required to add fluid to the system when no fluid remains in the fluid source after replenishment.

Yet another independent advantage of the present invention is that, in some aspects and in some constructions, the pressure source is supported on the vehicle. Therefore, a separate source of pressure is not required.

A further independent advantage of the present invention is that, in some aspects and in some constructions, the battery gas drawn from the batteries is not returned to the source of fluid or tank. The battery gas is separated in and vented from a gas diverter or gas separator.

Another independent advantage of the present invention is that, in some aspects and in some constructions, even if the venturi is above the fluid level in a fluid system, with the muzzle, the venturi will produce the necessary suction to cause fluid flow in the system.

Other independent features and independent advantages of the present invention are apparent to those skilled in the art upon review of the following detailed description, claims and drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A portion of a vehicle10, such as, for example, an electric car, a golf car or a utility vehicle, including at least one electrolyte battery14and a fluid supply system18for supplying fluid to the battery14, is illustrated inFIG. 1. The vehicle10includes a frame22supported by wheels for movement over ground. The vehicle10also includes a motor26(schematically shown) supported on the frame22and operable to power the vehicle10. In the illustrated construction, the motor26is electrically connectable with a plurality of batteries14(four shown) to selectively power the vehicle10. A steering assembly (not shown) is provided to control movement of the vehicle10.

The fluid supply system18includes a source of fluid, such as a tank30for holding fluid. In the illustrated construction, the tank30is supported on the frame22. The tank30includes (seeFIGS. 1–2) a container34into which fluid is poured through a removable cap38and from which fluid is supplied to the batteries14. The tank30may also include a strainer element (not shown) for removing debris from the fluid supply and preventing the debris from entering the tank30.

In some aspects and in the illustrated construction, the system18also includes (seeFIG. 2) a gas separator or gas diverter40, which includes a vent42for venting battery gas generated during operation and charging of the batteries14. In the illustrated construction, the vent42includes a flame arrestor46to prevent any flame from passing into the container34, should the vented gases ignite. In the illustrated construction, the gas diverter40is supported on the frame22.

In the illustrated construction, the gas diverter40has a volume about the size of the air space of a battery cell58. It should be understood that, in other constructions (not shown), the gas diverter40may be larger or smaller than the size of the air space of the battery cell(s)58.

The fluid supply system18also includes a hydraulic circuit50connecting the battery14to the tank30. The hydraulic circuit50includes a fluid supply member (not shown) provided by, in the illustrated construction, a filling pod54and connectable to a battery cell58. Fluid is supplied to the cell58through the fluid supply member, and gases are vented from the battery cell58through the fluid supply member. The filling pod54(shown inFIG. 1) may include a number of fluid supply members, each associated with and supplying fluid to a battery cell58.

The hydraulic circuit50also includes a vacuum source62. In some aspects and in the illustrated construction, the vacuum source62is supported on the frame22. The vacuum source62includes a pump66and a jet pump eductor or venturi70. The vacuum source62also includes a conduit74connectable between the outlet of the pump66and the venturi70. The venturi70defines a motive fluid inlet or first inlet78, a suction fluid inlet or second inlet82, and a discharge fluid outlet or venturi outlet86.

In the construction shown inFIG. 2, the hydraulic circuit50also includes a conduit90connectable between the gas diverter40and the battery cell58. The gas diverter40acts as a fluid supply tank for the fluid supply system18. The gas diverter40receives fluid from the tank30by a conduit94, which acts as a water trap between the tank30and the gas diverter40. The conduit94remains filled with fluid even when the tank30and gas diverter40are empty, so that only fluid will pass between the tank30and the gas diverter40. Gas is vented only through the vent42and is not passed to the tank30, because of the water trap provided by the conduit94, preventing the battery gas from being vented when the operator removes the fill cap38.

It should be understood that, in some aspects and in other constructions (not shown), the gas diverter40may be used with another vacuum source (not shown) to separate and divert any battery gas drawn from the battery cells58by such a vacuum source. It should also be understood that, in some aspects and in other constructions (not shown), the gas diverter40may be supported off the vehicle10such as at a replenishment station or on a replenishment cart to separate and divert any battery gas from the battery cells58caused by the vacuum source or pressure source at such a station or on such a cart.

The hydraulic circuit50includes a conduit98connectable between the battery cell58and the vacuum source62. A conduit102is connectable between the gas diverter40and the vacuum source62, and a conduit106is connectable between the vacuum source62and the gas diverter40.

The vehicle10also includes an on-board computer110(illustrated inFIG. 2). The on-board computer110is similar to the controller described in U.S. Pat. No. 6,087,805, issued Jul. 11, 2000, which is hereby incorporated by reference. Generally, the on-board computer110records the amount of energy in the battery14and determines when to allow the battery14to be charged. When the energy in the battery14falls below a predetermined level, the on-board computer110will allow the battery14to be charged.

The on-board computer110also controls the replenishment of battery fluid. The on-board computer110controls operation of the pump66. The on-board computer110monitors the energy (in ampere-hours) removed from the battery14and uses the record of removed energy to determine the timing of battery charging. The on-board computer110also determines the total duration of a charging cycle by measuring the rate of change of the charging current. The on-board computer110determines the amount of charge on the battery14by measuring the energy added to the battery14during charging.

In addition, by keeping a history of the removal and supply of energy to the battery14during operation and charging, respectively, the on-board computer110determines when the pump66should be activated so that fluid is supplied to the battery14. The on-board computer110estimates the fluid level in the battery14and activates the pump66, when necessary, to supply fluid to the battery14.

It should be understood that, in other constructions (not shown), the fluid supply system18may include a sensor (not shown) for sensing the fluid level in the battery14. Such a sensor would provide a signal to the on-board computer110to indicate the fluid level in the battery14and/or that fluid replenishment is necessary, and the on-board computer110would then activate the pump66to supply fluid to the battery14.

The venturi70is shown in more detail inFIGS. 3–5. In some aspects and in the illustrated construction, the venturi70is supported on the frame22. The venturi70includes a nozzle114which directs a high velocity fluid stream through the venturi70. The size and shape of the nozzle114can be modified to effect changes in the fluid flow and suction parameters. The venturi70also includes a first inlet78, a second inlet82, and a venturi outlet86. Fluid flow through the venturi70is illustrated inFIG. 4.

As shown inFIGS. 5–6, a muzzle118is connectable between the venturi outlet86and the gas diverter40. The muzzle118captures the high velocity fluid stream and collects enough fluid at the venturi outlet86to direct the fluid against the walls of the venturi70and to submerge the venturi outlet86. A small amount of back pressure is generated at the venturi outlet86, which allows suction at the second inlet82. The suction at the second inlet82causes fluid flow from the battery cell58through the conduit98. Filling of the muzzle118also converts the high velocity, low volume flow of the nozzle114to a low velocity, high volume flow to return the fluid to the gas diverter40. The muzzle118(seeFIGS. 5–6) includes openings122to allow the fluid to pass through to the gas diverter40. The total cross-sectional area of the openings122in the muzzle118is greater than the cross-sectional area of the venturi outlet86, such that fluid flow is slightly restricted after the high velocity stream is slowed down by the venturi70.

The muzzle118allows the venturi70to function as described above even though the venturi outlet86may be above the fluid level in the gas diverter40. If, in the system18, the venturi outlet86is below the fluid level, the fluid surrounding the venturi outlet86would create the back pressure, and the muzzle118may not be necessary.

It should be understood that, in some aspects and in other constructions (not shown), the muzzle118may be supported off the vehicle10and used with a venturi70which is supported off the vehicle10(i.e., in a replenishment station or on a replenishment cart). In such constructions, the muzzle118ensures proper operation of the venturi70even if the venturi70is positioned above the fluid level in such a system (not shown).

In the construction shown inFIG. 2, fluid is initially supplied to the tank30. During fluid replenishment, the pump66is operated by the on-board computer110, which causes fluid flow from the gas diverter40through the conduit102. The fluid flows through the pump outlet74and through the first inlet78. Fluid flows through the nozzle114and through the venturi70and collects at the muzzle118. As fluid collects at the muzzle118, back pressure develops in the venturi70, and a vacuum is generated at the second inlet82, which causes fluid flow from the battery cell58through the conduit98and through the second inlet82. Filling of the muzzle118also converts the high velocity, low volume flow of the nozzle114to a low velocity, high volume flow to return the fluid to the gas diverter40. As the characteristics of the fluid flow in the venturi70change, a vacuum is generated at the second inlet82, which causes fluid flow from the battery cell58through the conduit98and through the second inlet82. The vacuum also causes fluid flow from the gas diverter40through the conduit90to the battery cell58to replenish the battery cell58in a closed loop.

Preferably, replenishment of fluid to the battery cell(s)58, if necessary, is accomplished during charging of the battery14under the control of the on-board computer110. During the initial portion of the charging cycle, fluid is supplied to the battery cells58, and the battery14is charged. Any fluid and gas flowing from the battery cells58flows to the gas diverter40and is vented from the system18. During this initial portion of the charging cycle, little gas is typically produced by the battery cells58.

As the charging cycle continues (for example, at about three-quarters of the cycle), more gas begins to be produced by the battery cells58. During this portion of the charging cycle, fluid is not supplied to the battery cells58. The vacuum source62does not operate to draw battery gas from the battery cells58. Any gas flowing from the battery cells58is separated in the gas diverter40and vented from the system18.

It should be understood that, in some other operations, charging of the battery14and replenishment of the battery cells58may be conducted in another manner. For example, replenishment of fluid to the battery cells58may be provided separately from charging of the battery14(before or after charging). Also, replenishment may be conducted during another portion(s) of the charging cycle or during the whole charging cycle.

An alternative construction of a fluid supply system18A is illustrated inFIG. 7. Common elements are identified by the same reference number “A”.

The construction shown inFIG. 7is similar to the construction illustrated inFIG. 2. However, as shown inFIG. 7, the tank30A is connected to the pump66A rather than to the gas diverter40A. The gas diverter40A acts as a fluid supply source to the battery cell (not shown, but similar to battery cell58A), and the tank30A acts as a fluid supply source to the pump66A. The tank30A is connected to the gas diverter40A through the conduit94A, the gas diverter40A is connected to the battery cell, and the battery cell is connected to the second inlet82A of the venturi70A.

In the construction shown inFIG. 7, fluid is initially supplied to the tank30A. During fluid replenishment, the pump66A is operable to cause fluid flow from the tank30A through the pump66A. The fluid flows through the pump outlet74A and through the first inlet78A. Fluid flows through the venturi70A and collects downstream of the venturi70A. As the fluid collects downstream of the venturi70A, the fluid is converted from the high velocity, low volume flow to a low velocity, high volume flow to return the fluid to the gas diverter40A. As the characteristics of the fluid flow in the venturi70change, a vacuum is generated at the second inlet82A, which causes fluid flow from the battery cell58A through the second inlet82A. The vacuum also causes fluid flow from the gas diverter40A to the battery cell58A to replenish the battery cell58A in a closed loop.

It should be understood that the constructions of the fluid supply system18shown inFIGS. 2 and 7may be used in a single or multi-battery systems. It should also be understood that, in the multi-battery system, the fluid supply system18may include more than one battery14connected in series, parallel, or series/parallel combination.

One or more of the above-identified or other independent features and independent advantages of the invention are set forth in the following claims: