Patent Application
20080292948
The embodiments disclosed relate generally to batteries and more particularly to batteries with improved cooling systems and to methods of cooling batteries.
In electric vehicles and in hybrid electric vehicles and non-vehicle applications (e.g., locomotives, off-highway mining vehicles, marine applications, cranes, buses, and automobiles), batteries are essential components used to store a portion of the energy that is regenerated during braking for later use during motoring or generated for later use when the demand is low, thus increasing fuel efficiency.
As it will be apparent to one of ordinary skill,
As illustrated in
In general, battery-operating environments are harsh due, at least in part, to large changes in environmental temperature commonly encountered. In addition, charge and discharge are accomplished under severe conditions, including significant changes in battery operating temperatures due to large amounts of discharging current at the time of acceleration of a vehicle and large amounts of charging current at the time of breaking. In addition, optimum performance requires that these batteries be maintained uniformly within a given temperature range, which depends on the type of battery used, thus requiring that cooling and/or heating be provided. Many different types of batteries are known to exits; however, current high-temperature batteries, such as Sodium Nickel Chloride batteries, have to be heated to operating temperatures above 270° C. In the conventional battery 11, cooling is accomplished with airflow through the cooling plates 16, as explained, and an electric heater 28 is provided to raise the temperature of the battery to the desired operating level. As the size of the conventional battery 11 increases, it becomes more difficult to maintain the temperature of the battery uniformly and large airflow rates are required to provide the needed cooling. In the operation of electric and hybrid vehicles, several sources of low-temperature (relative to operating temperatures of the batteries) heat reservoirs exist, but the use of heat regeneration for the purpose of cooling a battery is unknown to these authors.
It would therefore be desirable to develop a battery having an improved cooling system with increased heat transfer effectiveness, increased cooling uniformity and reduced power requirement, among others.
One or more of the above-summarized needs or others known in the art are addressed by batteries that include a plurality of insulated cells electrically interconnected to each other and at least one liquid-circulating cooling plate to cool the battery.
Batteries according to embodiments of the disclosed inventions also include a plurality of cooling plates, a plurality of cells disposed between cooling plates, a button sheet to support the cells, a plurality of insulating sheets disposed between the cells, a plurality of bus bars electrically interconnecting the plurality of cells, and means for cooling the battery.
The above brief description sets forth features of the various embodiments of the present invention in order that the detailed description that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, other features of the invention that will be described hereinafter and which will be for the subject matter of the appended claims.
In this respect, before explaining several embodiments of the invention in detail, it is understood that the various embodiments of the invention are not limited in their application to the details of the construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which the disclosure is based, may readily be utilized as a basis for designing other structures, methods, and/or systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing Abstract is to enable a patent examiner and/or the public generally, and especially scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Accordingly, the Abstract is neither intended to define the invention or the application, which only is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Embodiments of the subject matter disclosed relate generally to batteries and more particularly to batteries with improved heating and cooling systems and to methods of heating and cooling batteries. By use of waste heat recirculation and/or improved liquid-circulating heat exchangers, improved heat transfer effectiveness, increased heating and/or cooling uniformity, and reduced power requirements are accomplished either individually or in any combination, among other advantageous features, as will be apparent to those of ordinary skill based on the subject matter disclosed. In addition, those of ordinary skill will appreciate that the various embodiments disclosed herein for cooling and/or heating a battery are not dependent on each other, i.e., each may be implemented without the other and various combinations are within the scope of the subject matter disclosed, as it will become apparent. Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, several embodiments of the improved batteries and heating and/or cooling systems will be described.
When heat a battery 30, one of the advantageous features of the embodiments illustrated in
As further explained below, embodiments of the subject matter disclosed may separately or in combination with the exemplary embodiments of
An alternative embodiment of the liquid-circulating cooling plate 34 is shown in
Different sources of waste heat in the vehicle carrying the battery 30 may be used to supply heating and/or cooling to the battery 30.
As illustrated, the energy transfer system 60 includes at least two heat exchangers 64 and 66, a pump 68, a diverter valve 70, a fluid reservoir 72, and a plurality of interconnected pipes, as further explained below. As understood by those of ordinary skill in the art, the fluid reservoir 72 is not required for the proper operation of the energy transfer system 60. However, when used, the fluid reservoir 72 may serve as an expansion chamber and a source of make-up fluid. Normally, the energy transfer system 60 is connected to the array of batteries 62. As used herein and appreciated by those of ordinary skill, the word “pipe” encompasses pipes, tubes, channels, and ducts or any other structure for transporting/flowing a fluid and the expression “connected” is used broadly to include direct connection of the different components or the use of valves and other devices (such as flow meters, etc) disposed between the different components interconnected by pipes. In addition, the type of pipe used in its construction does not substantially affect the operation and performance of the energy transfer system 60. Furthermore, although the array of batteries 62 has been illustrated, a single battery 30 may be alternatively used.
In the energy transfer system 60, when heating the array of batteries 62, a fluid 76 from the fluid circulated in the system is pumped by the pump 68 through the heat exchanger 64, where the fluid temperature is raised by heat transfer thereto from a first source 78. Heat from the first source 78 may be from an electric heater powered by an electric power source from the vehicle or may be regenerated from other sources in the vehicle, such as, for example, exhaust gases from an engine in the vehicle or heat generated during dynamic braking of the vehicle. As used herein throughout, dynamic braking relates to a braking force applied by traction motors for controlling speed or for slowing the vehicle down. That is, when a traction motor is not needed to provide a driving force, it can be reconfigured (via power switching devices) so that the motor operates as a generator. In conventional locomotives, for example, the energy generated in the dynamic braking mode is typically transferred to resistance grids mounted on the locomotive housing. Thus, the dynamic braking energy is converted to heat and dissipated from the system. In other words, electric energy generated in the dynamic braking mode is typically wasted in conventional vehicles. The heated fluid 76 from the heat exchanger 64 then flows in and out of the array of batteries 62 through inlets 80 and outlets 82 of the individual batteries 30, thereby heating the individual batteries 30 in the array of batteries 62. As illustrated, after leaving the batteries 30, the fluid 76 returns to the pump 68.
When heating the battery 30, the heat transfer from the fluid 76 to each battery 30 in the array of batteries 62 may take place in several different internal heat exchanges, depending on the configuration of the batteries 30. For example, the fluid flow through each of the batteries 30 may be through the heat exchanger 32 (shown in
As previously explained, in use, the temperature of the battery 30 may exceed a maximum value of a desired range, thus requiring that cooling be provided so as to maintain the battery operating temperature within the desired range. In the energy transfer system 60, when cooling the array of batteries 62, the fluid 76, after passing through the pump 68, is diverted by the diverter valve 70 into the heat exchanger 66, where its temperature is lowered by heat transfer therefrom to a second source 84. The second source 84 may be cooling water or oil from the vehicle and the heat added thereto may be eventually dissipated in a radiator of the vehicle, for example. Similar to the heating mode, the cooled fluid 76 from the heat exchanger 66 flows in and out of the array of batteries 62 through the inlets 80 and the outlets 82, thereby cooling each of the batteries 30 in the array of batteries 62, and returns to the pump 68. Although other heat exchangers may be used while cooling the battery 30, as understood by those of ordinary skill in the applicable arts, liquid-circulating cooling plates 34 are favored.
As just described during the heating cycle, the heat transfer from the fluid 76 to the batteries 30 in the array of batteries 62 may take place in one or several different internal heat exchangers, depending on the configuration of the individual batteries 30, such as the heat exchanger 32 or a plurality of liquid-circulating cooling plates 34. However, as understood by those of ordinary skill, a plurality of diverter valves may be used in each of the batteries 30 so as to direct the flow of the fluid 76 though a particular heat exchanger for cooling the battery and through a different heat exchanger for heating the battery. For example, the fluid 76 may flow through the heat exchanger 32 for heating and through a plurality of liquid-circulating cooling plates 34. Alternatively, the fluid 76 may flow through both the heat exchanger 32 and the plurality of liquid-circulating cooling plates 34 for both heating and cooling. Although the fluid 76 has been illustrated as being a liquid, alternatively, the fluid 76 may also be a gas, for example, air. As understood by those of ordinary skill, one of the advantageous features of the energy transfer system 60 is its ability to regenerate energy from waste energy sources within the vehicles carrying the batteries 30. In addition, for high-temperature batteries, initial battery heating may be provided by flowing the fluid 76 through the heat exchanger 66 since the temperature of the fluid 76 will be lower than the temperature of the fluid from the second source 84.
In operation, electric vehicles, hybrid-electric vehicles and non-vehicle applications (e.g., locomotives, off-highway mining vehicles, marine applications, cranes, buses and automobiles) have several waste heat sources, the energy from which is simply dissipated to the surrounding environment. In the exemplary case of a locomotive, for example, waste heat is dissipated from the engine cooling water, the engine block, the engine oil, the engine exhaust gases, and from dynamic braking.
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In the illustration of
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Methods for controlling the temperature of a battery are also within the scope of the subject matter disclosed herein. Such methods include: the transferring of heat to a battery from a first heat source so that the temperature of the battery increases from an initial temperature to a first threshold value, the first threshold value being lower than an operating temperature range or when the first heat source is available; and the transferring of heat to the battery from a second heat source until the temperature of the battery is within the operating temperature range. Once the battery temperature is above the desired range, the disclosed systems are configured to transferring the heat from the battery to the first heat source. The first heat source is selected from the group consisting of water from a radiator of an engine of a vehicle that includes the battery, oil from the engine, heat from a block of the engine, exhaust gas from the engine, dynamic braking from the vehicle, and combinations thereof and the second heat source includes an electric heater. As explained hereinabove, the transferring of heat to the battery from the first heat source includes flowing a liquid through a liquid-circulating heat exchanger within the battery and the transferring of heat from the battery to the first heat source when the temperature of the battery is above the operating temperature range includes flowing a liquid through a plurality of liquid-circulating cooling plates within the battery.
While the disclosed embodiments of the subject matter described herein have been shown in the drawings and fully described above with particularity and detail in connection with several exemplary embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes, and omissions are possible without materially departing from the novel teachings, the principles and concepts set forth herein, and advantages of the subject matter recited in the appended claims. Hence, the proper scope of the disclosed innovations should be determined only by the broadest interpretation of the appended claims so as to encompass all such modifications, changes, and omissions. In addition, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Finally, in the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.
