Refrigeration – Using electrical or magnetic effect – Thermoelectric; e.g. – peltier effect
Reexamination Certificate
1999-03-01
2001-05-08
McDermott, Corrine (Department: 3744)
Refrigeration
Using electrical or magnetic effect
Thermoelectric; e.g., peltier effect
C062S003200, C136S203000
Reexamination Certificate
active
06226994
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a thermoelectric element unit that makes use of a thermoelectric semiconductor element, such as a Peltier element, and a thermoelectric cooling or heating device provided with the same.
BACKGROUND OF THE INVENTION
Thermoelectric elements that use thermoelectric semiconductor elements made of compounds such as bismuth/tellurium compounds, iron/silicon compounds, or cobalt/antimony compounds are used in applications such as cooling/heating devices. Such a thermoelectric element is convenient as a cooling/heating source that does not use liquids or gases, takes up little space, is not subject to rotational friction, and does not require maintenance.
This thermoelectric element generally comprises two types of thermoelectric semiconductor element, p-type and n-type, arranged alternately in an array, with the thermoelectric semiconductor elements being connected to electrodes by soldering to form a “&pgr;”-shaped series circuit; the thermoelectric semiconductor elements and metal electrodes are sandwiched between ceramic substrates having metal films, and such an assembly is widely used as a thermoelectric module.
The structure of a thermoelectric module that is known in the art is shown in
FIGS. 16A and 16B
. In this case,
FIG. 16A
is a front view and
FIG. 16B
is a perspective view. As shown in these figures, thermoelectric semiconductor elements
63
consisting of n-type and p-type thermoelectric semiconductor elements are arrayed alternately. Upper and lower surfaces of the thermoelectric semiconductor elements
63
are connected with the upper surfaces thereof being connected by metal electrodes
62
and the lower surfaces thereof being connected by metal electrodes
64
, so that all of the thermoelectric semiconductor elements
63
are eventually connected electrically in series. The connections between the upper and lower metal electrodes
62
and
64
and the thermoelectric semiconductor elements
63
are performed by soldering. The metal electrodes
62
and
64
at the upper and lower sides are connected onto metallized ceramic substrates
61
and
65
, respectively, to fix the entire assembly together. The thus constructed thermoelectric element is usually called a thermoelectric module.
A DC power source is connected to electrodes at each end of this thermoelectric module, and, when a current flows in the direction from each n-type thermoelectric semiconductor element to a p-type thermoelectric semiconductor element, the Peltier effect ensures that the upper portion of the “&pgr;” shape acts as an absorbing-side cold junction (CJ) and the lower portion thereof acts as a radiating-side hot junction (HJ). Reversing the connection direction of the power source changes the directions in which heat is absorbed and emitted. This phenomenon is utilized so that the thermoelectric element can be used in a cooling/heating device.
Such a thermoelectric module is useful in a wide range of applications, from the cooling of devices such as large-scale integrated circuits (LSIs), computer central processing units (CPUs), and lasers, to use in insulated refrigerators.
If such a thermoelectric module is used as a cooling device, it is necessary to disperse heat efficiently from the heat-radiating side. Methods that are used in the art for dispersing heat from the heat-radiating side of a thermoelectric module include an air-cooling method wherein radiator fins
71
are attached to the heat-radiating side of the thermoelectric module
60
and an air-flow from a fan
72
is directed towards those radiator fins
71
, as shown in
FIG. 17A
, and a liquid-cooling method wherein a liquid-cooling jacket
81
is attached to the heat-radiating side of the thermoelectric module
60
and a coolant passes within this liquid-cooling jacket
81
. In addition, a Peltier cooling device is known, which uses aluminum substrates with oxidized surfaces instead of the ceramic surfaces, and which is capable of efficiently cooling the aluminum substrate on the heat-radiating side by using a liquid-cooling jacket provided with injection nozzles. Note that the hollow arrows in
FIG. 17A
indicate the flow of air and the solid arrows in
FIG. 17B
indicate the flow of coolant. In both
FIGS. 17A and 17B
, CL denotes a cooling load.
However, since the thermoelectric semiconductor elements in each of these cooling devices have a structure such that they are cooled indirectly through a ceramic substrate on the lower sides thereof, the heat cannot be dispersed efficiently from the heat-radiating side of the thermoelectric module. In addition, the ceramic substrates
61
and
65
that are fixed above and below the thermoelectric module of
FIG. 16A
form a rigid structure, so that large thermal stresses are inevitably applied to the thermoelectric semiconductor elements
63
during operation, and thus the lifetime of these thermoelectric semiconductor elements is short.
It is therefore an objective of this invention to provide a thermoelectric element which can minimize any drop in the cooling efficiency is minimized and also extract the maximum from the capabilities of thermoelectric semiconductor elements, by directly cooling the thermoelectric semiconductor elements and metal electrodes on a heat-radiating side thereof.
Another objective of this invention is to provide a thermoelectric element that can have an extended lifetime, by reducing thermal stresses applied to the thermoelectric semiconductor elements.
A further objective of this invention is to provide a thermoelectric cooling or heating device that has a high level of cooling efficiency or heating efficiency, by using this thermoelectric element.
A still further objective of this invention is to provide a thermoelectric cooling or heating device that can keep the temperature of a heat exchange fluid at a constant value, even when it is used over a long period of time or when the ambient temperature changes.
SUMMARY OF THE INVENTION
A thermoelectric element in accordance with this invention comprises: a partitioning plate having electrical insulating properties; a p-type thermoelectric semiconductor element and an n-type thermoelectric semiconductor element fixed to the partitioning plate in a state passing through the partitioning plate; a first metal electrode connected to a first surface of the p-type thermoelectric semiconductor element and the n-type thermoelectric semiconductor element; and a second metal electrode connected to a second surface of the p-type thermoelectric semiconductor element and the n-type thermoelectric semiconductor element.
A thermoelectric cooling or heating device in accordance with this invention comprises the structural essentials of the thermoelectric element of this invention, and is further provided with a heat exchange vessel for accommodating said second metal electrode and the portions of said thermoelectric semiconductor element that protrude from said partioning plate on the side of the second metal electrode and also for accepting the passage of a fluid for heat exchange therethrough.
In the thermoelectric element in accordance with this invention, there is no ceramic substrate fixed to either of the first metal electrode and the second metal electrode, thus reducing thermal stresses applied to the thermoelectric semiconductor elements.
In addition, the second metal electrode and the portions of the p-type thermoelectric semiconductor element and the n-type thermoelectric semiconductor element that protrude from the partitioning plate on the side of the second metal electrode, are directly cooling or heating within the heat exchange vessel of the thermoelectric cooling or heating device of this invention, so the cooling or heating efficiency thereof is increased.
Furthermore, in the thermoelectric cooling or heating device of this invention, the second metal electrode has a shape such that the surface area of the surface that is fixed to the p-type thermoelectric semiconductor element and the n-type thermoelectric semiconductor element is larger than the surface
Morino Isao
Yamada Kazukiyo
Dellett and Walters
Jiang Chen-Wen
McDermott Corrine
Sel Application Co., Ltd.
LandOfFree
Thermoelectric element and thermoelectric cooling or heating... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoelectric element and thermoelectric cooling or heating..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoelectric element and thermoelectric cooling or heating... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2555444