JP7187899B2 - thermoelectric generator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric generator comprising a plurality of thermoelectric conversion elements connected in series or parallel to each other.

Patent Literature 1 discloses a thermoelectric generator configured by connecting in parallel a plurality of thermoelectric conversion element groups (referred to as "strings") each configured by connecting a plurality of thermoelectric conversion elements in series. It is

Japanese Patent Application Laid-Open No. 2010-010637 (Fig. 1)

In Patent Document 1, different strings have the same number of thermoelectric conversion elements, and the same number of thermoelectric conversion elements are connected in series to form one string. Therefore, if the amount of heat received by the thermoelectric generator varies depending on the position due to a small heat source, uneven heating, or localized heating, the Since the temperature difference between the thermoelectric conversion elements varies and the output characteristics of the individual thermoelectric conversion elements vary, it becomes difficult to operate the thermoelectric generator efficiently as a whole. The difference in output characteristics is not limited to variations in temperature difference, but may occur due to individual differences even if the temperature difference is constant.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoelectric generator capable of suppressing the influence of variations in the output characteristics of thermoelectric conversion elements and operating efficiently as a whole.

In one aspect of the present invention, a first thermoelectric conversion element group having a plurality of identical thermoelectric conversion elements arranged in a direction perpendicular to the direction in which the temperature difference is formed; having a smaller number of the same thermoelectric conversion elements than the first thermoelectric conversion element group arranged in a direction perpendicular to the thermoelectric conversion element group, provided in a region having a higher temperature than the first thermoelectric conversion element group, and a second thermoelectric conversion element group connected in parallel with each other , the first thermoelectric conversion element group and the second thermoelectric conversion element group are connected in series with each other, and the first thermoelectric A thermoelectric power generator is provided in which the thermoelectric conversion elements of the conversion element group have a smaller temperature difference during power generation than the thermoelectric conversion elements of the second thermoelectric conversion element group.

In another form, a first thermoelectric conversion element group having a plurality of identical thermoelectric conversion elements arranged side by side in a direction perpendicular to a direction in which a temperature difference is formed, and in which the thermoelectric conversion elements are connected in series with each other. and having a smaller number of the same thermoelectric conversion elements than the first thermoelectric conversion element group arranged in a direction perpendicular to the direction in which the temperature difference is formed, and more than the first thermoelectric conversion element group a second thermoelectric conversion element group provided in a high-temperature region and having thermoelectric conversion elements connected in series, wherein the first thermoelectric conversion element group and the second thermoelectric conversion element group are Provided is a thermoelectric power generator in which the thermoelectric conversion elements of the first thermoelectric conversion element group are connected in parallel to each other, and the thermoelectric conversion elements of the second thermoelectric conversion element group have a smaller temperature difference during power generation. .

According to the present invention, the thermoelectric conversion elements can be efficiently operated by the first thermoelectric conversion element group and the second thermoelectric conversion element group, and the thermoelectric power generator as a whole can be more efficiently operated. can be operated. When the thermoelectric conversion elements of the first thermoelectric conversion element group and the second thermoelectric conversion element group are connected in parallel with each other, the current can be set more efficiently for each group. When the thermoelectric conversion elements of the conversion element group and the second thermoelectric conversion element group are connected in series with each other, the voltage can be set more efficiently for each group.

FIG. 1 is a schematic diagram showing the overall configuration of a thermoelectric generator according to one embodiment of the present invention. FIG. 2 is an explanatory diagram showing changes in output characteristics according to the temperature difference of the thermoelectric conversion element according to the embodiment. FIG. 3 is an explanatory diagram schematically showing a first example of a wiring pattern of the thermoelectric conversion element according to the embodiment; FIG. 4 is an explanatory diagram schematically showing a second example of the wiring pattern of the thermoelectric conversion element according to the embodiment. FIG. 5 is a schematic diagram showing the overall configuration of a thermoelectric generator according to another embodiment of the invention. FIG. 6 is an explanatory diagram schematically showing a first example of a connection pattern of the thermoelectric conversion element according to the embodiment; FIG. 7 is an explanatory diagram schematically showing a second example of the wiring pattern of the thermoelectric conversion element according to the embodiment. FIG. 8 is an explanatory diagram schematically showing the configuration of a waste heat recovery device equipped with a thermoelectric generator according to still another embodiment of the present invention. FIG. 9 is an explanatory diagram showing a temperature difference formed in the thermoelectric conversion element according to the same embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows the overall configuration of a thermoelectric generator 1a according to an embodiment of the present invention, together with a heat flow Fh from a heat source (not shown) indicated by a thick line with an arrow. For convenience, FIG. 1 shows the direction parallel to the heat flow Fh as the vertical direction L of the thermoelectric generator 1 and the direction perpendicular thereto as the horizontal direction W. As shown in FIG.

A thermoelectric generator (hereinafter simply referred to as "thermoelectric generator") 1a according to the present embodiment includes a plurality of thermoelectric conversion elements 11 arranged in a matrix in the longitudinal direction L and the lateral direction W (Fig. 4. A total of 12 thermoelectric conversion elements 11, 3 in the horizontal direction W, are shown, but the total number of thermoelectric conversion elements 11 and the numbers arranged in the vertical direction L and the horizontal direction W are not limited to this. , needless to say). The thermoelectric conversion element 11 has a high temperature or heating side surface (the upper surface of the thermoelectric conversion element 11 shown in FIG. 1) and a low temperature or cooling side surface (also the bottom surface of the thermoelectric conversion element 11). Based on the Seebeck effect, a potential difference is formed between both surfaces to generate an electromotive force. In addition to the thermoelectric conversion elements 11, the thermoelectric generator 1a includes a cooling unit 12 that cools the low temperature side surface of the thermoelectric conversion element 11 or maintains the temperature lower than the high temperature side surface of the thermoelectric conversion element 11, and the electric power generated by the thermoelectric conversion element 11. and a power converter 13 (FIGS. 3 and 4) that converts and forms the output of the thermoelectric generator 1a. In this embodiment, the cooling unit 12 is kept at a constant temperature by circulating a coolant, and the power conversion unit 13 converts the power generated by each thermoelectric conversion element 11 by maximum power point tracking (MPPT) control. , the thermoelectric generator 1 as a whole is controlled to the maximum power point.

In the thermoelectric conversion device 1, the high temperature side surface of the thermoelectric conversion element 11 is directly or indirectly exposed to the heat flow Fh from the heat source, and the flow Fh is exposed from the heat source. Since the amount of heat to be transported is lost as it moves away, the surface on the high temperature side has a particularly high temperature (thermoelectric conversion element 11h), a low temperature (thermoelectric conversion element 11l), and an intermediate one (thermoelectric conversion element 11l). element 11m) and are formed. In FIG. 1, the region occupied by the three thermoelectric conversion elements 11h on the most upstream side with respect to the heat flow Fh is defined as a high-temperature region Rh, and the region occupied by the three thermoelectric conversion elements 11l on the most downstream side and the adjacent three thermoelectric conversion elements 11l on the upstream side. is a low-temperature region Rl, and the region occupied by the other three thermoelectric conversion elements 11m is indicated as an intermediate region Rm. It can be changed as appropriate according to variations. For example, when the amount of heat lost from the flow F is small, the intermediate region Rm is omitted, and the region R occupied by the thermoelectric conversion element 11 is divided into two, an upstream high temperature region Rh and a downstream low temperature region Rl. It is possible to separate

Here, the temperature Th of the high temperature side surface of the thermoelectric conversion element 11 varies depending on the positional relationship with the heat source, that is, whether it is close or far from the heat source. If the temperature difference ΔT formed between them varies, the output characteristics of the individual thermoelectric conversion elements 11 will vary according to the variation in the temperature difference ΔT. 2 shows the output characteristics for each temperature difference ΔT of the thermoelectric conversion element 11, FIG. 2(a) shows the output characteristics at low temperature (temperature difference ΔTl), and FIG. ΔTh), respectively. In both FIGS. 2(a) and 2(b), the thick solid line indicates power P and the dotted line indicates voltage V. FIG.

It can be seen that the power P that can be generated is smaller and the range in which the current I can take is narrower at low temperatures than at high temperatures. Therefore, regardless of variations in the temperature difference ΔT, in other words, regardless of whether the temperature difference ΔT is large or small, if the thermoelectric conversion elements 11 are simply connected in series, the current I is rate-determined by the current of the thermoelectric conversion element 11 with a small temperature difference ΔT, and the current I becomes insufficient. On the other hand, if the thermoelectric conversion elements 11 were simply connected in parallel, the voltage V during power generation would be rate-determined by the voltage of the thermoelectric conversion elements 11 with a small temperature difference ΔT, resulting in an insufficient voltage V. However, it becomes difficult to efficiently operate the thermoelectric generator 1a as a whole.

Therefore, in the present embodiment, the thermoelectric conversion elements 11 having relatively close temperature differences ΔT form a group of elements (thermoelectric conversion element group), and the thermoelectric generation elements 11 belonging to the same group are connected in series or parallel to each other. In addition, the thermoelectric generator 1 is configured by connecting different thermoelectric conversion element groups to each other. Here, the group of elements or the group of thermoelectric conversion elements simply refers to a group of thermoelectric conversion elements 11 in an electrical connection relationship, and does not mean a group of layouts. It is not required to be placed as

FIG. 3 schematically shows a first example of the wiring pattern of the thermoelectric conversion element 11 according to this embodiment.

In the first example, a plurality of thermoelectric conversion elements 11l provided in the low temperature region Rl are connected in parallel to form a first group of thermoelectric conversion elements (corresponding to a "first thermoelectric conversion element group", hereinafter referred to as a "first thermoelectric conversion element group"). The thermoelectric conversion elements 11h provided in the high-temperature region Rh are referred to as a second group of thermoelectric conversion elements (referred to as a "second thermoelectric conversion element group", hereinafter referred to as a "second thermoelectric conversion element group"). Gh1 (referred to as "element group"). Further, the thermoelectric conversion elements 11m provided in the intermediate region Rm are connected in parallel to form a third group of thermoelectric conversion elements (hereinafter referred to as "third element group") Gm1.

Here, the number (for example, 1) of the thermoelectric conversion elements 11h forming the second element group Gh1 in the high temperature region Rh is the number (for example, 1) of the thermoelectric conversion elements 11l forming the first element group Gl1 in the low temperature region Rl. , 4) and the number (for example, 2) of the thermoelectric conversion elements 11m forming the third element group Gm1 in the intermediate region Rm, and the thermoelectric element forming the third element group Gm1 in the intermediate region Rm The number (for example, 2) of the conversion elements 11m is smaller than the number (for example, 4) of the thermoelectric conversion elements 11l forming the first element group Gl1 in the low temperature region Rl.

In this embodiment, the first element group Gl1, the second element group Gh1, and the third element group Gm1 are connected in series, and the power conversion unit 13 converts the power obtained through this series circuit. and the output of the thermoelectric generator 1a.

Here, the numbers m and n of the thermoelectric conversion elements 11l and 11h constituting the first element group Gl1 and the second element group Gh1, respectively, are limited to the numbers (m=4, n=1) shown in FIG. Any other combination of numbers may be used. For example, as long as the number n in the second element group Gh1 is smaller than the number m in the first element group Gl1, the second element group Gh1 may be the two or more thermoelectric conversion elements provided in the high temperature region Rh. It is also possible to form by 11h. In this case, the thermoelectric conversion elements 11h belonging to the second element group Gh1 are connected in parallel. The numbers m and n of the thermoelectric conversion elements 11l and 11h are preferably set within the range represented by the following equation (1). Min(ΔTh _i=1 to _n ) is a function for extracting the minimum value of the temperature difference ΔTh in the second element group Gh1, and Max(ΔTh _i =1 to _n ) is the temperature difference in the second element group Gh1. It is a function for extracting the maximum value of the difference ΔTh. For example, when the temperature difference ΔThi in the high temperature region Rh is 40° C. and the temperature difference ΔTli in the low temperature region Rl is 10° C., m = 4 and n = 1 are in a relationship of 20 ≤ 40 ≤ 80, The numbers m and n of the thermoelectric conversion elements 11l and 11h in the first example satisfy the relationship of the following formula (1).
(1/2) Min(ΔTh i= ₁ to _n )≦ΣΔTl _i=1 to _m ≦2Max(ΔTh _i=1 to _n ) (1)

For the sake of explanation, FIG. 3 shows an example in which four thermoelectric conversion elements 11l form one first element group Gl1 and one thermoelectric conversion element 11h forms a total of two second element groups Gh1. However, the numbers of the first and second element groups Gl1 and Gh1 are not limited to this. For example, the number of the second element groups Gh1 may be three or more, or one may be only

FIG. 4 schematically shows a second example of the wiring pattern of the thermoelectric conversion element 11 according to this embodiment.

In the second example, a plurality of thermoelectric conversion elements 11l provided in the low temperature region Rl are connected in series to form a first element group (corresponding to a "first thermoelectric conversion element group") Gl2, and a high temperature The thermoelectric conversion elements 11h provided in the region Rh are classified into a second element group (corresponding to a "second thermoelectric conversion element group") Gh2. Furthermore, the thermoelectric conversion elements 11m provided in the intermediate region Rm are connected in series to form a third element group Gm2.

Here, as in the first example, the number of thermoelectric conversion elements 11h (for example, 1) forming the second element group Gh2 is equal to the number of thermoelectric conversion elements 11l (for example, 1) forming the first element group Gl2. , 4) and the number (for example, 2) of the thermoelectric conversion elements 11m that make up the third element group Gm2, and the number of the thermoelectric conversion elements 11m that make up the third element group Gm2 (for example, 2) is smaller than the number (for example, 4) of the thermoelectric conversion elements 11l that constitute the first element group Gl2.

Then, the first element group Gl2, the second element group Gh2, and the third element group Gm2 are connected in parallel, and the electric power obtained through this parallel circuit is converted by the power converter 13 to generate thermoelectric power. Let it be the output of the device 1a.

Here, the numbers m and n of the thermoelectric conversion elements 11l and 11h constituting the first element group Gl2 and the second element group Gh2, respectively, are combinations other than the numbers (m=4, n=1) shown in FIG. may be the number, and the number is preferably within the range represented by the above formula (1). Then, as long as the number n in the second element group Gh2 is smaller than the number m in the first element group Gl2, the second element group Gh2 is set to two or more thermoelectric conversion elements provided in the high temperature region Rh. 11h. In this case, the thermoelectric conversion elements 11h belonging to the second element group Gh2 are connected in series.

Furthermore, FIG. 4 is an example in which four thermoelectric conversion elements 11l form one first element group Gl2, and one thermoelectric conversion element 11h forms a total of two second element groups Gh2 for the sake of explanation. , the number of the first and second element groups Gl2 and Gh2 is not limited to this, for example, the number of the second element group Gh1 may be three or more, It may be only one.

(Description of actions and effects)
The present embodiment is configured as described above, and the effects obtained by the present embodiment are summarized below.

First, in the first example, a plurality of thermoelectric conversion elements 11l are connected in parallel to form the first element group Gl1 on the low temperature side, and the number is smaller than that of the first element group Gl1 (1 A second element group Gh1 on the high-temperature side is formed by the thermoelectric conversion elements 11h of 11h, and the first element group Gl1 and the second element group Gh1 are connected in series to form the thermoelectric conversion device 1a. With this configuration, it is possible to set the current I that can efficiently operate the thermoelectric conversion elements 11l and 11h in the first element group Gl1 and the second element group Gh1, respectively, and thermoelectric power generation. The device 1a as a whole can be operated more efficiently. Here, when a plurality of thermoelectric conversion elements 11h constitute the second element group Gh1, the plurality of thermoelectric conversion elements 11h are connected in parallel to form one second element group Gh1.

Secondly, in the second example, a plurality of thermoelectric conversion elements 11l are connected in series to form a first element group Gl2 on the low temperature side, and the number is smaller than that of the first element group Gl2 (1 A second element group Gh2 on the high-temperature side is formed by the thermoelectric conversion elements 11h of 11h, and the first element group Gl2 and the second element group Gh2 are connected in parallel to form the thermoelectric conversion device 1a. With this configuration, it is possible to set a voltage V that can efficiently operate the thermoelectric conversion elements 11l and 11h in the first element group Gl2 and the second element group Gh2, and thermoelectric power generation. The device 1 as a whole can be operated more efficiently. Here, when a plurality of thermoelectric conversion elements 11h constitute the second element group Gh2, the plurality of thermoelectric conversion elements 11h are connected in series to form one second element group Gh2.

Third, thermoelectric conversion elements 11l (temperature difference ΔTl) and 11h (temperature difference ΔTh) having relatively close temperature differences ΔT during power generation form groups Gl (Gl1, Gl2) and Gh (Gh1, Gh2), By connecting the thermoelectric conversion elements 11l and 11h of each group in series or parallel to each other, the influence of variations in the temperature differences ΔTl and ΔTh between the thermoelectric conversion elements 11l and 11h on the efficiency of the entire thermoelectric generator 1a is suppressed. , the thermoelectric conversion device 1a as a whole can be efficiently operated.

Fourthly, by forming the second element group Gh with a plurality of thermoelectric conversion elements 11h, it is possible to provide the thermoelectric generator 1a capable of outputting a larger amount of electric power.

In the above description, the relationship between the number m of the thermoelectric conversion elements 11l forming the first element group Gl and the number n of the thermoelectric conversion elements 11h forming the second element group Gh is defined as the thermoelectric conversion elements 11l, It is defined from the viewpoint of the temperature differences ΔTl and ΔTh formed at 11h. By setting the numbers m and n to satisfy the above formula (1), the output characteristics of the first element group Gl and the second element group Gh are brought closer to each other as a whole group. By enabling power generation at the maximum output point of the thermoelectric conversion elements 11h constituting the second element group Gh, the operation of the thermoelectric generator 1 as a whole can be made more efficient.

However, the relationship between the numbers m and n of the thermoelectric conversion elements 11l and 11h in the first and second element groups Gl and Gh, respectively, is not limited to this. It is also possible to define from the viewpoint of P/ΔT, which is the ratio between the power P at the maximum output point and the power at the maximum output point at the temperature difference ΔT during power generation.

When defining from the viewpoint of the ratio P/ΔT between the temperature difference ΔT and the voltage P at the maximum output point, the first element group Gl is formed by a plurality of thermoelectric conversion elements 11l having a relatively small ratio P/ΔT. A second element group Gh is formed by the thermoelectric conversion elements 11h having a larger ratio P/ΔT than the thermoelectric generation elements 11l of the first element group Gl. Forming the second element group Gh with a smaller number of thermoelectric conversion elements 11h than the first element group Gl is the same as in the previous example.

In this way, the thermoelectric conversion elements 11l and 11h having relatively similar output characteristics according to the temperature difference ΔT form groups Gl and Gh, and the thermoelectric conversion elements 11l and 11h in each group are connected in series or parallel to each other. Therefore, the thermoelectric generator 1 can be efficiently operated as a whole regardless of variations in output characteristics or output differences due to individual differences between the thermoelectric conversion elements 11l and 11h.

In this case, the relationship between the numbers m and n is that the ratio P/ _ΔTl of the thermoelectric conversion elements 11l forming the first element group Gl is Kli, and the ratio of the thermoelectric conversion elements 11h forming the second element group Gh is Using P/ΔTh as Kh _i , the following equation (2) is obtained.
(1/2) Min (Kh _{i = 1} to _n ) ≤ ΣKl _{i = 1} to _m ≤ 2Max (Kh _{i = 1-n} ) (2)

On the other hand, when defining from the viewpoint of the power P at the maximum output point in the temperature difference ΔT, the first element group Gl is formed by a plurality of thermoelectric conversion elements 11l having relatively small power P, and the first element group Gl A second element group Gh is formed by the thermoelectric conversion elements 11h having a larger electric power P than the thermoelectric generation elements 11l. As in the previous example, the second element group Gh is formed of thermoelectric conversion elements 11h that are smaller in number than the first element group Gl.

In this way, the thermoelectric conversion elements 11l and 11h having relatively similar output characteristics at the temperature difference ΔT during power generation form groups Gl and Gh, and the thermoelectric conversion elements 11l and 11h in each group are connected in series or parallel to each other. As a result, it is possible to form a group in consideration of variations in output characteristics or differences in output during actual power generation, and to efficiently operate the thermoelectric generator 1a as a whole. If the temperature difference ΔT during power generation is constant over the entire thermoelectric generator 1a, the effect of variation in output characteristics due to individual differences between the thermoelectric conversion elements 11l and 11h can be mitigated, and power generation efficiency can be improved. can.

In this case, the relationship between the numbers m and n is such that the voltage at the maximum output point of the thermoelectric conversion elements 11l forming the first element group Gl is _Pli , and the voltage at the thermoelectric conversion element 11h forming the second element group Gh is Assuming that the voltage at the maximum output point is Ph _i , the following equation (3) is obtained.
(1/2) Min (Ph _{i = 1} to _n ) ≤ ΣPl _{i = 1} to _m ≤ 2Max (Ph _{i = 1} to _n ) (3)

Furthermore, the output characteristics of the thermoelectric conversion elements 11l and 11h during power generation can be evaluated not only by the electric power P but also by the current I or voltage V at the maximum output point at the temperature difference ΔT during power generation.

That is, when the output characteristics of the thermoelectric conversion elements 11l and 11h are evaluated based on the current I at the maximum output point, the first element group Gl is formed by a plurality of thermoelectric conversion elements 11l with a relatively small current I, while the first element group Gl A second element group Gh is formed by the thermoelectric conversion elements 11h having a larger current I than the thermoelectric conversion elements 11l of the element group Gl, and the thermoelectric conversion elements 11l and 11h of each group are arranged in the same manner as in the example shown in FIG. Connect in parallel with each other. This makes it possible to evaluate variations in output characteristics during power generation from the viewpoint of the current I, and to efficiently operate the thermoelectric generator 1a as a whole.

The relationship between the numbers m and _n of the thermoelectric conversion elements 11l and 11h in this case is that the current at the maximum output point of the thermoelectric conversion elements 11l constituting the first element group Gl is Ili, and the current at the second element group Gh is Assuming that the current at the maximum output point of the thermoelectric conversion element 11h is _Ihi , the following equation (4) is obtained.
(1/2) Min (Ih _{i = 1} to _n ) ≤ ΣIl _{i = 1} to _m ≤ 2Max (Ih _{i = 1} to _n ) (4)

On the other hand, when the output characteristics of the thermoelectric conversion elements 11l and 11h are evaluated by the voltage V at the maximum output point, a plurality of thermoelectric conversion elements 11l having a relatively small voltage V form the first element group Gl, A second element group Gh is formed by thermoelectric conversion elements 11h having a higher voltage V than the thermoelectric conversion elements 11l of the first element group Gl, and the thermoelectric conversion elements 11l and 11h of each group are arranged in the same manner as in the example shown in FIG. , in series with each other. This makes it possible to evaluate variations in output characteristics during power generation from the viewpoint of the voltage V, and to operate the thermoelectric generator 1a as a whole efficiently.

The relationship between the numbers m and n of the thermoelectric conversion elements 11l and 11h in this case is such that the voltage at the maximum output point of the thermoelectric conversion elements 11l constituting the first element group Gl is _Vli , and the voltage at the second element group Gh is The voltage Vh _i at the maximum output point of the thermoelectric conversion element 11h is given by the following equation (5).
(1/2) Min (Vh _{i = 1} to _n ) ≤ ΣVl _{i = 1} to _m ≤ 2Max (Vh _{i = 1} to _n ) (5)

(Description of other embodiments)
In the above description, when the temperature difference ΔT formed in the thermoelectric conversion element 11 varies according to the position with respect to the heat source, the thermoelectric conversion elements 11l and 11h having the similar temperature difference ΔT form a group, and the temperature An example has been described in which the number of thermoelectric conversion elements 11l constituting the low-temperature side group (first element group Gl) with the small difference ΔT is increased.

However, the compensation for variations in the temperature difference ΔT is not limited to this. It is also possible by increasing the thermal resistance that is formed.

FIG. 5 shows, as an example according to another embodiment of the present invention, an entire thermoelectric generator 1b in which the magnitude of thermal resistance formed by the thermoelectric conversion elements 11l and 11h is different between the high temperature region Rh and the low temperature region Rl. configuration. As in FIG. 1, the thick line Fh with an arrow indicates the flow of heat from the heat source.

In the present embodiment, the thermoelectric conversion elements 11h (11ha, 11hb) in the high temperature region Rh are stacked in the direction in which the temperature difference ΔTh is formed, and the thermal resistance formed by the thermoelectric conversion elements 11l, 11h is is relatively large (thermoelectric conversion elements 11ha and 11hb), and is smaller in the low temperature region Rl than in the high temperature region Rh (thermoelectric conversion element 11l). As a result, the temperature difference ΔT formed in one thermoelectric conversion element 11l, 11h is brought close to each other in the high temperature region Rh and the low temperature region Rl, and the influence of the positional difference with respect to the heat source on the output characteristics of the thermoelectric conversion elements 11l, 11h is reduced. Suppress.

Specifically, the plurality of thermoelectric conversion elements 11l provided in the low temperature region Rl are arranged side by side in a direction perpendicular to the direction in which the temperature difference ΔTl is formed, while the plurality of thermoelectric conversion elements 11ha provided in the high temperature region Rh , 11hb are superimposed on each other in the direction in which the temperature difference ΔTh is formed, and are arranged in two stages. For the sake of convenience, FIG. 5 shows the thermoelectric conversion elements 11ha arranged in the upper stage and the thermoelectric conversion elements 11hb arranged in the lower stage.

FIG. 6 schematically shows a first example of the wiring pattern of the thermoelectric conversion element 11 according to this embodiment.

In the first example, the thermoelectric conversion elements 11l in the low temperature region Rl are connected in parallel to form a first element group (corresponding to a “first thermoelectric conversion element group”) Gl1, and the thermoelectric conversion elements in the high temperature region Rh are connected in parallel. The conversion elements 11h are connected in parallel to form a second element group (corresponding to a "second thermoelectric conversion element group") Gha1 and Ghb1. Then, the first element group Gl1 and the second element groups Gha1 and Ghb1 are connected in series with each other.

In the example shown in FIG. 6, the four thermoelectric conversion elements 11l in the low temperature region Rl form the first element group Gl1, and the two thermoelectric conversion elements 11h in the high temperature region Rh form the second element groups Gha1 and Ghb1. However, the number of thermoelectric conversion elements 11l and 11h constituting each group Gl1, Gha1, and Ghb1 is not limited to this, and can be appropriately selected according to the actual temperature difference ΔT during power generation. is. For example, when the temperature difference ΔTl in the low temperature region Rl is smaller and the current that can be generated by one thermoelectric conversion element 11l is small, the number of the thermoelectric conversion elements 11l constituting the first element group Gl1 is increased to output It is possible to alleviate the variation in characteristics. On the other hand, when the temperature difference ΔT per thermoelectric conversion element between the low temperature region Rl and the high temperature region Rh becomes close due to the adjustment of the thermal resistance, the first element group Gl1 and the second element groups Gha1 and Ghb1 , the number of thermoelectric conversion elements 11l and 11h in each group may be made equal (for example, the number of thermoelectric conversion elements 11h forming the second element groups Gha1 and Ghb1 may be four, respectively).

FIG. 7 schematically shows a second example of the wiring pattern of the thermoelectric conversion element 11 according to this embodiment.

In the second example, the thermoelectric conversion elements 11l in the low temperature region Rl are connected in series to form a first element group (corresponding to a “first thermoelectric conversion element group”) Gl2, and the thermoelectric conversion elements in the high temperature region Rh are connected in series. The conversion elements 11h are connected in series to form a second element group (corresponding to a "second thermoelectric conversion element group") Gha2 and Ghb2. Then, the first element group Gl2 and the second element groups Gha2 and Ghb2 are connected in parallel with each other.

As in the first example, the number of thermoelectric conversion elements 11l and 11h constituting the first element group Gl2 on the low temperature side and the second element groups Gha2 and Ghb2 on the high temperature side are the numbers shown in FIG. It is not limited, and can be appropriately selected according to the actual temperature difference ΔT during power generation. For example, when the temperature difference ΔTl in the low-temperature region Rl is smaller and the voltage that can be generated by one thermoelectric conversion element 11l is small, the number of thermoelectric conversion elements 11l constituting the first element group Gl2 is increased to output It is possible to alleviate variations in characteristics, and on the other hand, if the temperature difference ΔT per one thermoelectric conversion element becomes closer between the low temperature region Rl and the high temperature region Rh by adjusting the thermal resistance, the first element It is also possible to equalize the number of thermoelectric conversion elements 11l and 11h in each group between the group Gl2 and the second element groups Gha2 and Ghb2.

Furthermore, in each of the first and second examples, the number of stages when the thermoelectric conversion elements 11h in the high temperature region Rh are superimposed is not limited to two stages as shown in FIG. 5, and may be three or more stages. For example, when the amount of heat received with respect to the high temperature region Rh is larger and a larger temperature difference ΔTh is formed, the thermoelectric conversion element 11h is arranged in three or more stages. The number of the second element groups Gh can be appropriately selected according to the required output of the thermoelectric generator 1b, and is not limited to two. or more.

The second element group Gh on the high temperature side may be selected from the thermoelectric conversion elements 11h (11ha, 11hb) arranged in the same stage, or the thermoelectric conversion elements provided in different stages. 11h. In other words, two or three or more thermoelectric conversion elements 11h (11ha, 11hb, 11hc, . ”, appropriately selecting the same set or different sets of thermoelectric conversion elements 11h from the plurality of sets, and connecting them in parallel or in series to form the second element group Gh. It is possible.

Furthermore, in the above description, the influence of the positional difference with respect to the heat source on the output characteristics of the thermoelectric conversion elements 11 can be controlled by adjusting the number of the thermoelectric conversion elements 11l constituting the first element group Gl on the low temperature side, This effect was compensated by adjusting the thermal resistance through the thermoelectric conversion element 11h that constitutes the second element group Gh, but this effect was corrected by changing the configuration of the cooling unit 12 of the thermoelectric generator, and the thermoelectric conversion element 11 It is also possible to reduce the temperature difference ΔT formed in the .

As an example of such a case, FIG. 8 schematically shows the configuration of a thermoelectric generator 1c according to still another embodiment of the present invention. The thermoelectric generator 1c according to this embodiment constitutes a waste heat recovery device that recovers the heat emitted from the heat source 21, converts it into electricity, and outputs the electricity. FIG. 8 shows the heat flow Fh from the heat source 21 by a solid line with an arrow, and the coolant flow Fc through the cooling unit 12 of the thermoelectric generator 1c by a thick dotted line with an arrow. As the heat source 21 according to the present embodiment, an inverter for controlling an internal combustion engine and a traveling motor, which constitute a driving source of the vehicle, can be exemplified.

Exhaust air discharged from or passed through the heat source 21 is discharged outside the system through a waste heat passage 22 extending from the heat source 21 . Here, the thermoelectric conversion elements 11h, 11m, and 11l of the second, third, and first element groups Gh, Gm, and Gl constituting the thermoelectric generator 1c are arranged around the heat source 21 and the waste heat passage 22, and in the heat source 21. They are arranged in this order from the closest side. Specifically, the thermoelectric conversion elements 11h of the second element group Gh provided on the high temperature side are arranged around the heat source 21, and in the waste heat passage 22, on the side relatively far from the heat source 21 and on the low temperature side. The thermoelectric conversion elements 11l of the first element group Gl are arranged, and the third element group Gm is arranged along the waste heat passage 22 between the first element group Gl and the second element group Gh. of thermoelectric conversion elements 11m are arranged. Any of the thermoelectric conversion elements 11l, 11m, and 11h of the first to third element groups Gl, Gm, and Gh can receive heat from the heat source 21 or the waste heat passage 22 by the high temperature side surface thereof. are arranged as follows.

Here, as the connection pattern of the thermoelectric conversion elements 11l, 11m, and 11h according to this embodiment, it is possible to apply any of the above-described embodiments, but if the temperature differences ΔT are sufficiently close, can have the same number of thermoelectric conversion elements 11l, 11m, and 11h constituting the first to third element groups Gl, Gm, and Gh.

On the other hand, in the present embodiment, the coolant flow Fc through the cooling part 12 of the thermoelectric generator 1c is formed from the midstream region corresponding to the third element group Gm to the downstream region corresponding to the second element group Gh. and its direction is determined in a direction facing the heat flow Fh from the heat source 21, in other words, from downstream to upstream with respect to the heat flow Fh.

By setting the direction Fc in which the coolant flows in the direction opposite to the flow Fh of heat from the heat source 21 in this manner, the temperature difference ΔT formed in the thermoelectric conversion element 11 can It is possible to uniformly approach the entire thermoelectric power generation device 1c regardless of the position difference, suppressing variations in output characteristics caused by the temperature difference ΔT, and efficiently operating the thermoelectric power generation device 1c as a whole. and increase the waste heat recovery efficiency.

In the above explanation, the temperature difference ΔT varies due to the difference in the amount of heat received with respect to the high-temperature surface of the thermoelectric conversion element 11. may be caused by variations in

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. not on purpose. Various changes and modifications can be made to the above-described embodiment within the scope of matters described in the claims.

DESCRIPTION OF SYMBOLS 1a, 1b, 1c... Thermoelectric generator 11, 11l, 11m, 11h... Thermoelectric conversion element 12... Cooling part 13... Power conversion part 21... Heat source 22... Waste heat passage Rl... Low temperature area Rm... Intermediate area Rh... High temperature area Gl 1st element group Gm 3rd element group Gh 2nd element group

Claims (6)

a first thermoelectric conversion element group having a plurality of the same thermoelectric conversion elements arranged side by side in a direction perpendicular to the direction in which the temperature difference is formed, the thermoelectric conversion elements being connected in parallel;
The first thermoelectric conversion element group having a smaller number of the same thermoelectric conversion elements than the first thermoelectric conversion element group arranged side by side in a direction perpendicular to the direction in which the temperature difference is formed. a second thermoelectric conversion element group in which the thermoelectric conversion elements are connected in parallel with each other;
consists of
the first thermoelectric conversion element group and the second thermoelectric conversion element group are connected in series with each other ;
The thermoelectric conversion elements of the first thermoelectric conversion element group have a smaller temperature difference during power generation than the thermoelectric conversion elements of the second thermoelectric conversion element group,
thermoelectric generator. a first thermoelectric conversion element group having a plurality of the same thermoelectric conversion elements arranged side by side in a direction perpendicular to the direction in which the temperature difference is formed, the thermoelectric conversion elements being connected in series with each other;
The first thermoelectric conversion element group having a smaller number of the same thermoelectric conversion elements than the first thermoelectric conversion element group arranged side by side in a direction perpendicular to the direction in which the temperature difference is formed. a second thermoelectric conversion element group provided in a region having a higher temperature than the
consists of
the first thermoelectric conversion element group and the second thermoelectric conversion element group are connected in parallel to each other ;
The thermoelectric conversion elements of the first thermoelectric conversion element group have a smaller temperature difference during power generation than the thermoelectric conversion elements of the second thermoelectric conversion element group,
thermoelectric generator. The thermoelectric conversion elements of the first thermoelectric conversion element group have a smaller electric power at the maximum output point in the temperature difference during power generation than the thermoelectric conversion elements of the second thermoelectric conversion element group.
The thermoelectric generator according to claim 1 or 2. The thermoelectric conversion elements of the first thermoelectric conversion element group have a smaller current at the maximum output point in the temperature difference during power generation than the thermoelectric conversion elements of the second thermoelectric conversion element group, and are connected in parallel to each other. rice field,
The thermoelectric generator according to claim 1. The thermoelectric conversion elements of the first thermoelectric conversion element group have a smaller voltage at the maximum output point in the temperature difference during power generation than the thermoelectric conversion elements of the second thermoelectric conversion element group, and are connected in series with each other. rice field,
The thermoelectric generator according to claim 2. The first and second thermoelectric conversion element groups each include a plurality of the thermoelectric conversion elements,
The thermoelectric generator according to any one of claims 1-5 .

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