Phase change assisted heat sink

• US 6,239,502 B1
• Filed: 11/22/1999
• Issued: 05/29/2001
• Est. Priority Date: 11/22/1999
• Status: Expired due to Term

• Current Assignee: BAE Systems Controls Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Controls Incorporated (BAE Systems Plc)
• Inventors: Grewe, Timothy Michael, Osovski, Steve William
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US09/444,097
• Time in Patent Office: 554 Days
• Field of Search: 361/700, 361/701, 361/702, 361/704, 62/3.61, 180/65.2, 290/1 R, 290/1 A, 290/1 B, 290/2
• US Class Current: 290/1.00B
• CPC Class Codes: B60K 11/00 Arrangement in connection with cooling of propulsion units heating the interior space B60H; cooling internal combustion engines per se F01P
• CPC Class Codes: B60K 2001/003 with means for cooling the electrical propulsion units
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 2270/44 Heat storages, e.g. for cabin heating
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: F01P 1/06 Arrangements for cooling other engine or machine parts
• CPC Class Codes: F01P 2003/2278 Heat pipes
• CPC Class Codes: F01P 2050/24 Hybrid vehicles
• CPC Class Codes: F01P 2050/30 Circuit boards
• CPC Class Codes: H02K 2209/00 Specific aspects not provided for in the other groups of this subclass relating to systems for cooling or ventilating
• CPC Class Codes: H02K 7/006 Structural association of a motor or generator with the drive train of a motor vehicle
• CPC Class Codes: H02K 9/00 Arrangements for cooling or ventilating channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24
• CPC Class Codes: H02K 9/22 by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges
• CPC Class Codes: H05K 7/20 Modifications to facilitate cooling, ventilating, or heating
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

In an electric vehicle, the traction motor is driven from a battery by way of a controllable electric power switching arrangement. In normal operation of the switches of the switching arrangement, the power losses or heating of the switches depends upon the power being handled; during hard acceleration the power is high, and at constant speed on level ground the power is relatively small. Thus, the power “dissipated” by the switches varies with time. A cooling system transfers heat from the switching arrangement to ambient. During acceleration, the cooling system may not be able to limit the instantaneous temperature of the switches to the desired value. A phase-change heat “sink” coupled to the switches absorbs heat from the switches during hard acceleration, and returns the heat to the cooling system under more constant-speed conditions. In general, any electronic device which experiences transient power surges may use the same principle, thereby allowing the overall cooling system to be sized for average power, with the phase-change sink acting as an “integrator” to average the power by storing heat when the temperature tends to rise, and returning the heat when the temperature tends to fall. In an electric vehicle, braking is accomplished by returning energy to the battery, but when the battery is fully charged and can accept no more charge, braking may be accomplished by coupling the electric power to a cooled phase-change sink. The phase-change material may be iron.

Claims

1. A vehicle including:

an electric traction drive machine;

a source of electrical energy;

an electrical device which receives fluctuating amounts of electrical energy from one of said traction drive machine and said source of electrical energy, and which is heated by said electrical energy, and which if not cooled may be damaged;

a cooling system thermally coupled to said electrical device for cooling said electrical device by transfer of heat to the environment, said cooling system being dimensioned for transferring an average amount of the heat arising from said electrical energy, but not the peaks of said fluctuating amount; and

phase-change heat storage material thermally coupled to said electrical device and to said cooling system, for absorbing excess heat from said electrical device during said peaks, and for transferring stored heat to said cooling system at times other than the times of said peaks.

2. A vehicle according to claim 1, wherein said electrical device comprises a switch controlled for coupling energy to said electric traction drive machine from said source of electrical energy.

3. A vehicle according to claim 1, wherein said electrical device is a resistor, coupled for converting vehicle braking energy into heat.

4. A vehicle including

an electric traction drive machine;

a source of electrical energy;

a controllable switching arrangement coupled to said traction drive machine and to said source of electrical energy, for coupling energy between said source of electrical energy and said motor under the control of control signals;

operator-controlled control means coupled to said switching arrangement, for controlling the amount of energy coupled between said source and said machine by synthesizing a current waveform;

a cooling system coupled to said controllable switching arrangement, for transferring heat from said switching arrangement to ambient; and

a phase change energy transducer coupled to said cooling system and to said switching arrangement, for transiently absorbing heat generated by said switching arrangement in excess of that which said cooling system can instantaneously trasfer.

5. An apparatus, comprising:

an electrical machine;

a source of electrical energy;

controllable switching means coupled to said machine and to said source of electrical energy, for providing energy to said machine from said source in an amount which varies in time, whereby the energy handled by said switching means varies with time, and the power-loss-generated heat in said switching means also varies with time;

cooling means coupled to said switching means, for transferring said heat from said switching means to ambient, whereby the instantaneous temperature of said switching means tends to vary in response to the power being handled by said switching means; and

phase change energy transducing means thermally coupled to said switching means and to said cooling means, for absorbing heat from said switching means when said instantaneous temperature of said switching means tends to rise, and for releasing heat to said cooling means when said instantaneous temperature of said switching means tends to fall, thereby tending to maintain said temperature of said switching means constant.