Energy Storage Module For Load Leveling In Lift Truck Or Other Electrical Vehicle
First Claim
1. A method for maintaining a level of charge between a battery and a load in an electrical vehicle, the method comprising the following steps:
- connecting a bank of super capacitors between an electrical load and a battery supplying power to the load;
isolating the super capacitors from the battery;
measuring a battery voltage at the battery;
measuring a capacitor voltage indicating the voltage on the bank of super capacitors;
calculating a voltage difference between the battery voltage and the capacitor voltage; and
charging the super capacitors when the voltage difference is greater than a predetermined minimum voltage, wherein the charged super capacitors reduce the rate of discharge from the battery to the electrical load.
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Abstract
An energy storage module for use in an electric vehicle, such as a lift truck, is disclosed. The energy storage module includes a bank of super capacitors or ultra-capacitors which are connected between the battery and the load. In operation, the energy storage module charges the capacitors, and uses the charged capacitors to level the load on the battery, limiting spikes in current draw, and assuring a substantially smooth discharge profile, wherein the battery discharge is substantially steady state. The energy storage module further includes sensors for determining when the battery and load are connected.
51 Citations
20 Claims
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1. A method for maintaining a level of charge between a battery and a load in an electrical vehicle, the method comprising the following steps:
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connecting a bank of super capacitors between an electrical load and a battery supplying power to the load; isolating the super capacitors from the battery; measuring a battery voltage at the battery; measuring a capacitor voltage indicating the voltage on the bank of super capacitors; calculating a voltage difference between the battery voltage and the capacitor voltage; and charging the super capacitors when the voltage difference is greater than a predetermined minimum voltage, wherein the charged super capacitors reduce the rate of discharge from the battery to the electrical load. - View Dependent Claims (2, 3, 4, 5, 6, 15, 16)
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7. An energy storage module for providing load leveling between a battery and an electrical load in an electrical vehicle, the energy storage module comprising:
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a battery connector for providing an electrical connection to a battery; a load connector for connection to the electrical load; a bank of super capacitors connected between the battery and the electrical load; and a controller connected the bank of super capacitors, the controller being programmed to; sense a battery voltage level and a capacitor voltage level; calculate a voltage difference between the battery voltage level and the capacitor voltage level; compare the voltage difference to a predetermined minimum voltage value; and charge the super capacitor bank when the voltage difference is greater than the predetermined minimum, wherein when the bank of super capacitors is charged, the charge stored in the bank of super capacitors is used to provide power to the load and to limit the draw from the battery, thereby increasing the time between battery charges. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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17. An electrical vehicle, comprising:
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a power unit, including a battery and an electrical load powered by the battery, the electrical load including a vehicle control system; a fork coupled to the power unit, and configured to be elevated and lowered by the vehicle control system; an energy storage module selectively connected between the battery and the load, wherein the energy storage module comprises; a bank of super capacitors connected between the battery and the load to level the load; and a controller connected to the battery connector, the load connector, and the bank of super capacitors, the controller being programmed to; sense a battery voltage level and a capacitor voltage level when the battery connector sensing device and the load connector sensing device indicate that the battery connector and the load connector are connected; calculate a voltage difference between the battery voltage level and the capacitor voltage level; compare the voltage difference to a predetermined minimum voltage value; and charge the super capacitor bank when the voltage difference is greater than the predetermined minimum. - View Dependent Claims (18, 19, 20)
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Specification