Heater with temperature detecting device and battery structure with the heater

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a battery structure with heater of a preferred embodiment;

FIG. 2 is a side view of the battery structure with heater of the embodiment;

FIG. 3 is a sectional view of the battery structure with heater, taken along a line P-P in FIG. 1;

FIG. 4 is a sectional view of the battery structure with heater, taken along a line Q-Q in FIG. 2;

FIG. 5 is a sectional view of a secondary battery of the present embodiment;

FIG. 6 is a perspective sectional view of a first heater (a second heater);

FIG. 7 is a perspective view of a first heater with temperature detecting device (a second heater with temperature detecting device);

FIG. 8 is a sectional view of a first laminated heater (a second laminated heater), taken along a line A-A in FIG. 7;

FIG. 9 is a sectional view of a mounting structure of a temperature sensor of the first heater with temperature detecting device (the second heater with temperature detecting device), taken along a line B-B in FIG. 7;

FIG. 10 is an explanatory view to show a cooling function of the battery structure with heater, taken along the line P-P of FIG. 1; and

FIG. 11 is a sectional view of a mounting structure of the temperature sensor of the heater with temperature detecting device in a modified form.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A detailed description of a preferred embodiment of a battery structure with heater (hereinafter, referred to as a “heater-equipped battery structure”) 10 according to the present invention will now be given referring to the accompanying drawings.

The heater-equipped battery structure 10 includes a battery pack 50, a first heater unit 60, and a second heater unit 70 as shown in FIGS. 1 and 2.

The battery pack 50 includes a housing case 40 constituted of a first housing member 20 and a second housing member 30, and a plurality of secondary batteries 100 (forty batteries in the present embodiment) housed in the housing case 40, as shown in FIG. 3. In the present embodiment, the battery pack 50 corresponds to a battery structure.

Each secondary battery 100 is a nickel-metal hydride storage sealed battery provided with a battery case 101, a positive terminal 161 and a negative terminal 162, as shown in FIG. 4. The battery case 101 has a resin case body 102 of a nearly rectangular box shape and a resin cover 103 of a nearly rectangular plate shape, as shown in FIG. 5. The case body 102 is internally divided into six compartments 124 by partition walls 125. Each compartment 124 accommodates an electrode plate group 150 (positive plates 151, negative plates 152, and separators 153) and an electrolyte (not shown). The electrode plate groups 150 individually accommodated in the compartments 124 are connected in series to one another. Thus, the secondary battery 100 of the present embodiment constitutes a battery module including six cells connected in series.

The electrode plate group 150 and the electrolyte (not shown) correspond to a power generating element. The cover 103 is provided with a safety valve 122.

In the present embodiment, as shown in FIG. 3, forty secondary batteries 100 configured as above are arranged in a row in a row direction X (a lateral direction in FIG. 3) and connected in series to one another.

The first housing member 20 is made of metal in a rectangular recessed form which includes a housing part 24 housing the secondary batteries 100 and a rectangular annular flange 23 surrounding an open end of the housing part 24. The second housing member 30 includes a rectangular recessed metal part 34 and a rectangular annular flange 33 surrounding an open end of the recessed part 34.

On the flange 33 of the second housing member 30, the secondary batteries 100 are fixedly placed (see FIGS. 3 and 4). Further, the first housing member 20 is fixed to the second housing member 30 with mounting bolts 11 so that the flange 23 is placed in contact with the flange 33 of the second housing member 30, containing the secondary batteries 100 in the housing part 24.

The thus configured battery pack 50 includes, as part of a bottom wall 34b of the recessed part 34 of the second housing member 30, a part 35 located in spaced relation to the secondary batteries 100, leaving a space S therefrom. This part 35 is hereinafter referred to as a “spaced part”. In the present embodiment, the outer surface of the spaced part 35 will be a surface to be heated (hereinafter, referred to as a “heated surface”) 35b as mentioned later.

As shown in FIG. 6, the first heater unit 60 includes a first heater 63 with temperature detecting device (hereinafter, simply referred to as a “first heater”), a first sheet 62, a first holder 65 that holds them, and a heat insulating member 68. The first heater 63 is bonded to a first surface (an upper surface in FIG. 6) 62b of the first sheet 62 which is bonded to a holding surface 65f of the first holder 65. The heat insulating member 68 is bonded to a surface 65g (a lower surface in FIG. 6) of the holder 65 opposite the holding surface 65f. Thus, the first heater unit 60 is constituted of the first heater 63, the first sheet 62, the first holder 65, and the heat insulating member 68 which are integrally bonded to one another.

The first heater 63 includes a first laminated sheet heater 61 and a temperature sensor 64 (corresponding to a temperature detecting device) as shown in FIG. 7.

The first laminated heater 61 is a sheet heater of a laminated structure, as shown in FIG. 8, including a first insulating resin film 61c, a second insulating resin film 61e, a heater element 61d placed between an inner surface 61g (a lower surface in FIG. 8) of the first insulating resin film 61c and an inner surface 61h (an upper surface in FIG. 8) of the second insulating resin film 61e, a first metal sheet 61b laminated on an outer surface 61j (an upper surface in FIG. 8) of the first insulating resin film 61c opposite the heater element 61d, and a second metal sheet 61f laminated on an outer surface 61k (a lower surface in FIG. 8) of the second insulating resin film 61e opposite the heater element 61d.

The heater element 61d is made of a nickel-chromium alloy foil and formed in a predetermined pattern extending along a plane, for example, in a strip-shaped serpentine pattern as shown by a dotted line in FIG. 7. The first and second insulating resin layers 61c and 61e are formed of polyimide films. The first and second metal sheets 61b and 61f are formed of aluminum plates.

The temperature sensor 64 includes a temperature detecting element 64b (a thermistor in the present embodiment) and a retainer 64c that retains the temperature detecting element 64b as shown in FIG. 9. The retainer 64c includes a retaining portion 64f retaining the temperature detecting element 64b and a cylindrical metal part 64d to be fastened (hereinafter, referred to as a “fastened part”). This temperature sensor 64 is fixedly coupled, at the fastened part 64d, to the first laminated heater 61 with a flat rivet 69 (corresponding to a metal fixing member and a mechanical fastening means) so that a temperature measuring portion 64g is in contact with an outer surface 61m of the first metal sheet 61b.

In the temperature sensor 64, the temperature detecting element 64b and the element-retaining portion 64f constitute the temperature measuring portion 64g.

Meanwhile, when the temperature sensor 64 is fastened to a portion of the first laminated heater 61 in which the first and second insulating resin films 61c and 61e are laminated with a mechanical fastening device such as a metal fixing member, the first and second insulating resin films 61c and 61e are apt to be deformed or distorted by the fastening power of the mechanical fastening device, causing generation of a gap between the temperature measuring portion 64g of the temperature sensor 64 and the outer surface 61m of the first metal sheet 61b. In such cases, accordingly, the temperature sensor 64 could not detect accurately the temperature of the first laminated heater 61. Furthermore, even after fastening, creep of the first and second insulating resin films 61c and 61e may affect the fastened portion, gradually decreasing the thickness of the fastened portions of the first and second insulating resin films 61c and 61e, thereby causing the fastening power to progressively go down. Consequently, the temperature sensor 64 may not accurately detect the temperature of the first laminated heater 61 in the long term.

In the first heater 63 with temperature detecting device according to the present embodiment, on the other hand, the first laminated heater 61 includes a heater metallic section 61p in which, of the heater element 61d, the first insulating resin film 61c, the second insulating resin film 61e, the first metal sheet 61b, and the second metal sheet 61f, only the first metal sheet 61b and the second metal sheet 61f are arranged in a lamination direction of the first heater 63 (in a vertical direction in FIG. 9), as shown in FIG. 9. To this heater metallic section 61p, the temperature sensor 64 is fixedly secured with the flat rivet 69. In other words, the temperature sensor 64 is fixed to the heater metallic section 61p with the flat rivet 69, without the heater element 61d, first insulating resin film 61c and second insulating resin film 61e.

Specifically, the heater metallic section 61p is formed with a through hole 61q through which a shaft 69b of the flat rivet 69 is inserted. The temperature sensor 64 is also formed with a through hole 64h through which a shaft 69b of the flat rivet 69 is inserted. Using the through holes 61q and 64h, the temperature sensor 64 and the heater metallic section 61p are fastened with the flat rivet 69 in the following manner.

The temperature sensor 64 is first disposed on the outer surface 61m of the first metal sheet 61b so that the through hole 61q of the heater metallic section 61p and the through hole 64h of the temperature sensor 64 are coaxially aligned with each other. In this state, the shaft 69b of the flat rivet 69 is inserted (from below in FIG. 9) into the through hole 61q of the heater metallic section 61p and the through hole 64h of the temperature sensor 64. Successively, an end of the shaft 69b of the flat rivet 69 is plastically deformed by fixing (forming a plastic-deformed end 69d), thereby holding the temperature sensor 64 and the heater metallic section 61p in pressure contact with each other in an axial direction of the flat rivet 69 (in the vertical direction in FIG. 9). Thus, the temperature sensor 64 is fastened to the heater metallic section 61p with the flat rivet 69 and hence fixed in contact with the outer surface 61m of the first metal sheet 61b.

When the temperature sensor 64 and the heater metallic section 61p are fastened to each other without the first and second insulating resin films 61c and 61e, the first and second insulating resin films 61c and 61e will not be distorted as above. The heater metallic section 61p is extremely rigid as compared with the first and second insulating resin films 61c and 61e and therefore is unlikely to be distorted by the fastening power of the flat rivet 69. This makes it possible to prevent the generation of a gap between the temperature sensor 64 and the outer surface 61m of the first metal sheet 61b. Accordingly, the temperature sensor 64 can be fixed to the first metal sheet 61b with the temperature measuring portion 64g of the temperature sensor 64 held in contact with the outer surface 61m of the first metal sheet 61b.

Further, the fastening power of the flat rivet 69 will not cause the first and second insulating resin films 61c and 61e to creep and hence the heater metallic section 61p is unlikely to creep. The temperature measuring portion 64g of the temperature sensor 64 can therefore be held in contact with the first metal sheet 61b over a long period of time.

The flat rivet 69 plastically deformed in itself (forming the plastic deformed portion 69d) fastens the temperature sensor 64 to the heater metallic section 61p. Accordingly, a decrease in fastening power over time is extremely small.

Furthermore, the temperature sensor 64 is fastened to the heater metallic section 61p with the flat rivet 69 inserted in the fastened part 64d made of metal (see FIG. 9). This fastened part 64d has the strength enough to keep its shape against the fastening power of the flat rivet 69 and thus can prevent the temperature sensor 64 from becoming deformed or distorted by the fastening power of the flat rivet 69. The fastened part 64d can also prevent the temperature sensor 64 from creeping after fastening with the flat rivet 69.

As a result, the temperature measuring portion 64g of the temperature sensor 64 can be stably held in contact with the first metal sheet 61b over long periods. In the first heater 63 with temperature detecting device, consequently, the temperature sensor 64 can accurately detect the temperature of the first laminated sheet heater 61 over long periods.

In the present embodiment, furthermore, the temperature sensor 64 is placed in a position surrounded (on three sides, in the present embodiment) by the heater element 61d in plan view of the first laminated heater 61 as shown in FIG. 7. The temperature sensor 64 can adequately detect the temperature of the first laminated heater 61.

In the case where the temperature sensor 64 is placed on an end area of the first laminated heater 61 away from the heater element 61d, the temperature detected by the temperature sensor 64 will be largely different from (very lower than) the actual temperature of the heater element 61d. When the temperature control (ON-OFF control or the like) of the heater is to be executed by use of such temperature sensor 64, the battery pack 50 may not be heated appropriately. As compared with this, the heater 63 with temperature detecting device in the present embodiment can reduce a difference between a detected temperature by the temperature sensor 64 and an actual temperature of the heater element 61d, so that the accuracy of temperature control of the first laminated heater 61 can be enhanced.

The first sheet 62 is an urethane foam sheet, which is placed between the first laminated heater 61 and the first holder 65 as shown in FIG. 6. This first sheet 62 is elastically deformable in a direction of its thickness (in a vertical direction in FIG. 6).

The first holder 65 is formed in recessed rectangular shape, including a holding part 65c internally holding the first laminated heater 61 and a rectangular annular flange 65b surrounding an open end of the holding part 65c. This flange 65b is formed with a plurality of through holes 65d each allowing a threaded portion 12b of a mounting bolt 12 to pass through.

The bottom wall 34b of the second housing member 30 is formed with threaded holes 34c in positions corresponding to the through holes 65d of the first heater unit 60. In the present embodiment, the threaded portion 12b of the mounting bolt 12 is inserted through the through hole 65d of the flange 65b and threadedly engaged in the threaded hole 34c of the bottom wall 34b of the second housing member 30, thereby detachably fastening the first heater unit 60 to an outer surface 34f of the bottom wall 34b of the second housing member 30.

As above, the first heater unit 60 is detachably provided outside the housing case 40 (i.e., on the outer surface 34f of the bottom 34b of the second housing member 30). Accordingly, the first heater unit 60 can easily be detached from and attached to the housing case 40 of the battery pack 50. This configuration can improve workability in maintenance, replacement, or the like for the first heater 63 with temperature detecting device.

Meanwhile, the heated surface 35b of the battery pack 50 includes a flat portion 35c to be heated (hereinafter, a “heated portion”) and a recess 35d recessed protruding into the inside of the battery pack 50 (into the space S). When the first heater unit 60 is fixed to the bottom 34b of the second housing member 30, the temperature sensor 64 is received in the recess 35d of the heated surface 35b by bringing the outer surface 61m of the first metal sheet 61b into contact with the flat heated portion 35c of the heated surface 35b. Thus, the temperature sensor 64 is placed in a position surrounded by the first laminated heater 61 (the first metal sheet 61b) and the recess 35d of the heated surface 35b. The temperature sensor 64 is unlikely to be cooled by outside air or the like and therefore can detect the temperature of the first laminated heater 61 adequately.

In the present embodiment, part of the bottom 34b of the second housing member 30 is shaped by press molding into a recessed form, which serves as the recess 35d of the heated surface 35b. This makes it possible to increase the strength of the bottom 34b of the second housing member 30.

In the present embodiment, additionally, the first sheet 62 is placed between the first laminated heater 61 and the first holder 65 and the first sheet 62 is elastically compressively deformed in the direction of thickness of the first laminated heater 61 (in the vertical direction in FIG. 6). The elastic force of the first sheet 62 caused by elastically compressively deformation brings the outer surface 61m of the first metal sheet 61 into close contact with the heated portion 35c. As a result, a gap is unlikely to be formed between the outer surface 61m of the first metal sheet 61b and the heated portion 35c. The first laminated heater 61 can heat the battery pack 50 adequately.

In particular, the outer surface of the metal sheet has a smaller variation in temperature distribution than the surface of the insulating resin film. Accordingly, when the outer surface 61m of the first metal sheet 61b is heated in close contact with the heated portion 35c, uneven heating of the heated portion 35c can be avoided. It is therefore possible to reduce uneven heating among the secondary batteries 100 forming the battery pack 50, thereby reducing variations in temperature among the secondary batteries 100.

The heat of the first laminated heater 61 can be transferred to the battery pack 50 adequately, so that the first laminated heater 61 can be prevented from excessively locally rising in temperature.

In the first heater 63, as shown in FIG. 9, the head 69c of the flat rivet 69 protrudes by a distance D1 from the outer surface 61n of the second metal sheet 61f (the outer surface of the first laminated heater 61). As shown in FIG. 6, however, the first sheet 62 made of urethane foam, placed on the outer surface 61n of the second metal sheet 61f, is deformed to absorb the protruding distance D1 of the head 69c of the flat rivet 69. Thus, the first sheet 62 adequately presses the outer surface 61n of the second metal sheet 61f to hold the outer surface 61m of the first metal sheet 61b in close contact with the heated portion 35c.

The second heater unit 70 includes, as shown by reference codes in parentheses in FIG. 6, a second heater 73 with temperature detecting device (hereinafter, simply referred to as a “second heater”), a second sheet 72, a second holder 75 that holds them, and a heat insulating member 78. As with the first heater unit 60, the second heater unit 70 is constituted of the second heater 73, the second sheet 72, the second holder 75, and the heat insulating member 78 which are integrally bonded to one another.

The second heater 73 includes a first laminated sheet heater 71 and a temperature sensor 64 (corresponding to a temperature detecting device).

The second laminated heater 71 is a sheet heater of a laminated structure, as shown by reference codes in parentheses in FIG. 8, including a first insulating resin film 71c, a second insulating resin film 71e, a heater element 71d placed between an inner surface 71g of the first insulating resin film 71c and an inner surface of 71h of the second insulating resin film 71e, a first metal sheet 71b laminated on an outer surface 71j of the first insulating resin film 71c opposite the heater element 71d, and a second metal sheet 71f laminated on an outer surface 71k of the second insulating resin film 71e opposite the heater element 71d.

In the second heater 73, as shown by reference codes in parentheses in FIG. 9, as with the first heater 63, the second laminated heater 71 includes a heater metallic section 71p in which, of the heater element 71d, the first insulating resin film 71c, the second insulating resin film 71e, the second metal sheet 71b, and the second metal sheet 71f, only the first metal sheet 71b and the second metal sheet 71f are arranged in a lamination direction of the second heater 73 (in the vertical direction in FIG. 9). To this heater metallic section 71p, the temperature sensor 64 is fixedly secured with the flat rivet 69. In other words, the temperature sensor 64 is fixed to the heater metallic section 71p with the flat rivet 69 without the heater element 71d, first insulating resin film 71c, and second insulating resin film 71e.

Accordingly, the fastening power of the flat rivet 69 will not cause the first and second insulating resin films 71c and 71e to be distorted and the heater metallic section 71p is unlikely to be distorted. This makes it possible to prevent the generation of a gap between the temperature sensor 64 and the outer surface 71m of the first metal sheet 71b. Accordingly, the temperature sensor 64 can be fixed to the first metal sheet 71b with the temperature measuring portion 64g of the temperature sensor 64 held in contact with the outer surface 71m of the first metal sheet 71b. Further, the fastening power of the flat rivet 69 will not cause the first and second insulating resin films 71c and 71e to creep and hence the heater metallic section 71p is unlikely to creep. Thus, the temperature measuring portion 64g of the temperature sensor 64 can be held in contact with the first metal sheet 71b over long periods.

As in the first heater 63 with temperature detecting device, the temperature sensor 64 is fastened to the heater metallic section 71p with the rivet 69 inserted in the fastened part 74d made of metal (see FIG. 9). As a result, the temperature measuring portion 64g of the temperature sensor 64 can be stably held in contact with the first metal sheet 71b over a long period of time. In the second heater 73, consequently, the temperature sensor 64 can accurately detect the temperature of the second laminated heater 71 over long periods.

Further, the temperature sensor 64 is placed in a position surrounded (on three sides, in the present embodiment) by the heater element 71d in plan view of the second laminated heater 71 as shown in FIG. 7. The temperature sensor 64 can adequately detect the temperature of the second laminated heater 71.

As shown by the reference codes in parentheses in FIG. 6, the second heater unit 70 is similarly detachably provided outside the housing case 40 (i.e., on the outer surface 34f of the bottom 34b of the second housing member 30). Accordingly, the second heater unit 70 can easily be detached from and attached to the housing case 40 of the battery pack 50. This configuration can improve workability in maintenance, replacement, or the like for the second heater 73.

Furthermore, when the second heater unit 70 is fixed to the bottom 34b of the second housing member 30 as shown by the reference codes in parentheses in FIG. 6, the temperature sensor 64 is received in the recess 35d of the heated surface 35b by bringing the outer surface 71m of the first metal sheet 71b into contact with the heated portion 35c of the heated surface 35b. Thus, the temperature sensor 64 is placed in a position surrounded by the second laminated heater 71 (the first metal sheet 71b) and the recess 35d of the heated surface 35b. The temperature sensor 64 is unlikely to be cooled by outside air or the like and therefore can detect the temperature of the second laminated heater 71 adequately.

The second sheet 72 is placed between the second laminated heater 71 and the second holder 75 and the second sheet 72 is elastically compressively deformed in the direction of thickness of the second laminated heater 71 (in the vertical direction in FIG. 6). The elastic force of the second sheet 72 caused by elastically compressively deformation brings the outer surface 71m of the first metal sheet 71b into close contact with the heated portion 35c. As a result, a gap is unlikely to be formed between the outer surface 71m of the first metal sheet 71b and the heated portion 35c. The second laminated heater 71 can heat the battery pack 50 adequately.

In particular, the outer surface of the metal sheet has a smaller variation in temperature distribution than the surface of the insulating resin film. Accordingly, when the outer surface 71m of the first metal sheet 71b is heated in close contact with the heated portion 35c, uneven heating of the heated portion 35c can be reduced. It is therefore possible to reduce uneven heating among the secondary batteries 100 forming the battery pack 50, thereby reducing temperature variations among the secondary batteries 100.

The heat of the second laminated heater 71 can be transferred to the battery pack 50 adequately, so that the second laminated heater 71 can be prevented from excessively locally rising in temperature.

The first and second laminated heaters 61 and 71 are heaters that can be energized or powered by a household AC power source to generate heat. The first heater 61 and the second heater 71 are electrically connected to an alternator plug 15 as shown in FIG. 3. Accordingly, the alternator plug 15 is connected to an outlet of the household AC power source to supply electric power to the first and second laminated heaters 61 and 71, thereby causing them to generate heat.

Here, a heating function of the heater-equipped battery structure 10 will be explained in detail.

In the heater-equipped battery structure 10 of the present embodiment, as mentioned above, the first heater 63 and the second heater 73 are placed on the outer surface 35b of the spaced part 35 of the second housing member 30 (the housing case 40) (see FIG. 3). This configuration allows the heat of the first laminated heater 61 and the second laminated heater 71 to be conducted to the spaced part 35, thus heating the air in the space S through the heated spaced part 35. Then, each secondary battery 100 is exposed to the heated air and heated.

According to the above heating manner, it is possible to prevent uneven heating among the secondary batteries 100 of the battery pack 50 and thus reduce variations in temperature among the secondary batteries 100. This makes it possible to reduce variations in output characteristics among the secondary batteries 100. The entire battery pack 50 can therefore produce stable output.

The temperature sensor 64 can accurately detect the temperature of the first laminated heater 61, so that the temperature control of the heater (ON-OFF control and others) can be conducted adequately by use of an output signal from the temperature sensor 64. In case the first laminated heater 61 abnormally rises in temperature due to some failures or malfunctions, for example, the abnormal rise in temperature of the first laminated heater 61 can be detected based on the output signal from the temperature sensor 64 and energization of the first laminated heater 61 is stopped immediately.

The above configuration can prevent the first laminated heater 61 from excessively rising in temperature and hence prevent an excessive temperature rise of each secondary battery 100 constituting the battery pack 50. This heater temperature control can also applied to the second laminated heater 71. In the present embodiment, the space S as well as the spaced part 35 exists between each of the first and second laminated heaters 61 and 71 and each of the secondary batteries 100. Accordingly, each secondary battery 100 can be prevented from excessively rising in temperature.

As shown in FIG. 6, the first heater unit 60 of the present embodiment is provided with the heat insulating member 68 under the lower surface 65g of the holder 65 opposite the holding surface 65f. Similarly, as shown in FIG. 7, the second heater unit 70 is also provided with the insulating member 78 under the lower surface 75g of the holder 75 opposite the holding surface 75f holding the second heater 71. Accordingly, the heat of the first and second laminated heaters 61 and 71 are unlikely to escape from the lower surfaces 65g and 75g of the holders 65 and 75.

In the heater-equipped battery structure 10 of the present embodiment, as shown in FIG. 3, a cooling device 90 is placed in the housing case 40. If the temperatures of the secondary batteries 100 rise to high temperatures, the cooling device 90 is operated to cool the secondary batteries 100. More specifically, as shown in FIG. 10, upon activation, the cooling device 90 takes in outside air through a first air hole 21 of the first housing member 20, delivers cooled air (outside air) through the inside of the housing case 40 including the space S, and discharges the heat of the secondary batteries 100 out of the structure 10 through a second air hole 22. Thus, each of the secondary batteries 100 can be cooled appropriately. In the present embodiment, particularly, no heater exists between each secondary battery 100 and the air passage (including the space S) and therefore each secondary battery 100 can be cooled efficiently.

A modified form is different only in a heater with temperature detecting device from the above embodiment and parts or components other than that heater are identical to those in the above embodiment. The following explanation is made with a focus on the differences from the above embodiment without repeatedly explaining the identical parts or components.

To be specific, as shown in FIG. 9, the above embodiment uses the first laminated heater 61 including the heater metallic section 61p in which, of the heater element 61d, the first insulating resin film 61c, the second insulating resin film 61e, the first metal sheet 61b, and the second metal sheet 61f, only the first and second metal sheets 61b and 61f are arranged in the lamination direction of the first laminated heater 61 (in the vertical direction in FIG. 9). The temperature sensor 64 is fixedly fastened to the heater metallic section 61p of the first laminated heater 61 with the flat rivet 69, constituting the first heater 63 with temperature detecting device.

On the other hand, the present modified form uses a first laminated heater 81 including a heater metallic section 81p in which, of the heater element 61d, the first insulating resin film 61c, the second insulating resin film 61e, the first metal sheet 61b, and a second metal sheet 81f, only the first metal sheet 61b is arranged in a lamination direction of the first laminated heater 81 (in a vertical direction in FIG. 11). A temperature sensor 64 is fastened to the heater metallic section 81p of the first laminated heater 81 with the flat rivet 69, constituting a first heater 83 with temperature detecting device.

The first heater 83 of the modified form differs in that the heater metallic section for fastening the temperature sensor 64 includes no second metal sheet from the first heater 63 with temperature detecting device of the above embodiment. According to the first heater 83 of the modified form, the protruding distance of the head of the flat rivet 60 from the outer surface of the second metal sheet can be reduced by an amount corresponding to the thickness of the second metal sheet as compared with that in the first heater 63 of the above embodiment.

As clearly seen from a comparison between FIGS. 9 and 11, specifically, the protruding distance of the head 69c of the flat rivet 69 from the outer surface of the second metal sheet can be reduced from D1 (the above embodiment) to D2 (the modified form). This reduction in protruding distance of the head 69c of the flat rivet 69 from the outer surface of the second metal sheet allows the first sheet 62 to more suitably press the outer surface 81n of the second metal sheet 81f, thereby holding the outer surface 61m of the first metal sheet 61b in close contact with the heated portion 35c.

Furthermore, as shown by reference codes in parentheses in FIG. 11, a second heater 93 with temperature detecting device is arranged, as with the first heater 83 with temperature detecting device, such that a heater metallic section 91p for fastening the temperature sensor 64 does not include a second metal sheet 91f. The protruding distance of the head 69c of the flat rivet 69 from the outer surface of the second metal sheet can be reduced by an amount corresponding to the thickness of the second metal sheet.

In the modified form, the flat rivet 69 may be replaced with a rivet having a head thinner than a portion of the first laminated heater 81 in which the heater element 61d, first insulating resin film 61c, second insulating resin film 61e, and second metal sheet 81f are laminated. This configuration is more preferable to keep the rivet head from protruding from the outer surface of the second metal sheet. The same applies to the second heater with temperature detecting device.

The present invention is explained referring to the above embodiment and the modified form, but the present invention may be embodied in other specific forms without departing from the essential characteristics thereof.

In the above embodiments, the battery pack 50 including the plurality of secondary batteries 100 (forty batteries in the embodiment) and the housing case 40 housing them is exemplified as a battery structure to be heated. Alternatively, the battery structure may be configured as a cell constituted of a single power generating element accommodated in a battery case or a battery module including a plurality of power generating elements and a battery case having a plurality of compartments individually accommodating the power generating elements. In other words, the cell, the battery module, or others may be configured to be directly heated by a heater.

In the above embodiment, the secondary battery 100 is exemplified as a battery module including the battery case 101 integrally formed with six compartments 124 and the power generating elements individually accommodated in the compartments 124. Alternatively, the secondary battery may be a cell comprising a single power generating element accommodated in a battery case.

In the above embodiment, the secondary battery 100 provided with the resin battery case 101 and others is used. The material of the battery case is not limited to resin and may be selected from metal or other materials. Although the secondary battery in the above embodiment is a nickel-metal hydride storage battery, the present invention can also be applied to the case where the secondary battery is one of other batteries (including a primary battery) such as a lithium ion battery.

In the above embodiments, the temperature sensor 64 is used for the temperature detecting device, which is fastened to the heater metallic section 61p or others with the flat rivet 69 and fixed to the outer surface 61m, 71m of the first metal sheet 61b, 71b of the first laminated heater 61, 71. However, another temperature detecting device such as a thermal fuse and a PTC thermistor may be used instead of the temperature sensor. Such device may be fastened similarly to the heater metallic section 61p or others with the flat rivet 69 and fixed to the outer surface 61m, 71m of the first metal sheet 61b, 71b of the first laminated heater 61, 71.

In the above embodiments, the mechanical fastening device for fastening the temperature sensor 64 to the heater metallic section 61p or others is the flat rivet 69, but may be another form such as a blind rivet, a metal a metal eyelet, a bolt, and a nut.

In the above embodiments, the outer surface 61m, 71m of the first metal sheet 61b, 71b is held in contact with the heated portion 35c of the heated surface 35b. An alternative is to turn the first heater 63 upside down to bring the outer surface 61n (71n, 81n, 91n) of the second metal sheet 61f (71f, 81f, 91f) into contact with the heated portion of the heated surface 35b.

While the presently preferred embodiment of the present invention has been shown and described, it is to be understood that this disclosure is for the purpose of illustration and that various changes and modifications may be made without departing from the scope of the invention as set forth in the appended claims.

Heater with temperature detecting device and battery structure with the heater

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CPC

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Priority Claims (1)