Heater unit and battery structure with heater

Abstract

There are provided a heater unit and a battery structure with heater, which are capable of heating the battery structure appropriately and preventing a heater (part or whole of the heater) itself from excessively increasing in temperature. A first heater unit is provided with a first sheet heater, a first holding member holding it, and a first sheet placed between a lower surface of a first heater and the first holding member in such a manner as to be deformable in at least a direction of thickness of the first heater. The first heater is deformed when the first heater unit is fixed to the battery pack 50, thereby pressing the lower surface of the first heater to bring an upper surface of the first heater into close contact with an outer surface (a surface to be heated) of a spaced part of the battery pack.

Description

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 sectional view of a first heater unit;

FIG. 7 is a sectional view of a second heater unit;

FIG. 8 is a perspective sectional view of a first heater (a second heater);

FIG. 9 is a partially enlarged sectional view of the battery structure with heater, including the first heater unit 60 and its surrounding;

FIG. 10 is a partially enlarged sectional view of the battery structure with heater, including the second heater unit 70 and its surrounding; and

FIG. 11 is an explanatory view to show a cooling function of the battery structure with heater, taken along the line P-P of FIG. 1.

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. 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, as shown in FIGS. 3 and 4. This part 35 is hereinafter referred to as a “spaced part”.

The first heater unit 60 includes a first heater 61, a first sheet 62, a first holder 65 that holds them, and a heat insulating member 68. The first heater 61 is bonded to an upper surface 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 61, the first sheet 62, the first holder 65, and the heat insulating member 68 which are integrally bonded to one another.

The first heater 61 is a sheet heater of a laminated structure, as shown in FIG. 8, including a heater element 61d extending along a plane in a predetermined pattern indicated by a dotted line, a first insulating resin layer 61c laminated on an upper surface 61g of the heater element 61d and a second insulating resin layer 61e laminated on a lower surface 61h of the heater element 61d, and a first metal layer 61b laminated on an upper surface 61j of the first insulating resin layer 61c and a second metal layer 61f laminated on a lower surface 61k of the second insulating resin layer 61e. The heater element 61d is made of nickel-chromium alloy. The first and second insulating resin layers 61c and 61e are formed of polyimide films. The first and second metal layers 61b and 61f are formed of aluminum plates.

The first sheet 62 is an urethane foam sheet, which is placed between a lower surface 61n (a second surface) and the first holder 65. This first sheet 62 is elastically deformable in a direction of thickness of the first heater 61 (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 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 as shown in FIG. 9.

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 as shown in FIG. 9. Each of the threaded holes 34c is configured to threadably engage with the threaded portion 12b of the mounting bolt 12. 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 tightened in the threaded hole 34c of the bottom wall 34b of the second housing member 30, thereby detachably fixing 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 61. In particular, the first heater unit 60 of the present embodiment is constituted of the first heater 61, the first sheet 62, the first holder 65, and the heat insulating member 68 which are integrally bonded to one another, so that the first heater unit 60 can be handled easily, facilitating a mounting work with respect to the battery pack 50 or other works.

Meanwhile, in the first heater unit 60 of the present embodiment, in an original state prior to fixation to the battery pack 50, the total thickness of the first heater 61 and the first sheet 62 is assumed to be L and the first heater 61 protrudes by a distance ΔL from a contact surface 65h of the flange 65b of the first holder 65 as shown in FIG. 6. The contact surface 65h of the flange 65b is a surface that makes contact with the outer surface 34f of the bottom 34b of the second housing member 30 when the first heater unit 60 is fixed to the battery pack 50 as shown in FIG. 9.

When this first heater unit 60 is fixedly placed on the outer surface 34f of the bottom 34b of the second housing member 30 as mentioned above, as shown in FIG. 9, the total thickness of the first heater 61 and the first sheet 62 is reduced from L to M (see FIG. 6). At that time, the first sheet 62 is elastically compressed and deformed by the distance ΔL (ΔL=L−M) (see FIG. 6) in the direction of thickness of the first heater 61 (in the vertical direction in FIG. 9). By an elastic force caused by this elastically compressive deformation, an upper surface 61m (a first surface) of the first heater 61 can be held in close contact with the outer surface 35b of the spaced part 35.

Particularly, in the first heater unit 60, the entire first sheet 62 is in contact with the lower surface 61n of the first heater 61. Thus, the entire lower surface 61n of the first heater 61 can be pressed by the elastic force of the first sheet 62, thereby adequately bringing the upper surface 61m of the first heater 61 into close contact with the outer surface 35b of the spaced part 35. As a result, no gap is formed between the upper surface 61m of the first heater 61 and the outer surface 35b of the spaced part 35, and therefore the battery pack 50 can be heated properly. Furthermore, the heat of the first heater 61 can appropriately be conducted to the battery pack 50, thereby preventing the temperature of the first heater 61 (part or whole of the first heater 61) itself from excessively increasing.

In the present embodiment, the outer surface 35b of the spaced part 35 corresponds to a surface to be heated (a heated surface).

The second heater unit 70 includes a second heater 71, a second sheet 72, a second holder 75 that holds them, and a heat insulting material 78, as shown in FIG. 7. The second heater 71 is bonded to an upper surface 72b of the second sheet 72 which is bonded to a holding surface 75f of the second holder 75. The heat insulating member 78 is bonded to a surface 75g (a lower surface in FIG. 7) of the holder 75 opposite the holding surface 75f. Thus, the second heater unit 70 is constituted of the second heater 71, the second sheet 72, the second holder 75, and the heat insulating member 78 which are integrally bonded to one another.

The second heater 71 is a sheet heater of a laminated structure, as shown by reference codes in parentheses in FIG. 8, including a heater element 71d extending along a plane in a predetermined pattern indicated by a dotted line, a first insulating resin layer 71c laminated on an upper surface 71g of the heater element 71d and a second insulating resin layer 71e laminated on a lower surface 71h of the heater element 71d, and a first metal layer 71b laminated on an upper surface 71j of the first insulating resin layer 71c and a second metal layer 71f laminated on a lower surface 71k of the second insulating resin layer 71c. The heater element 71d is made of nickel-chromium alloy. The first and second insulating resin layers 71c and 71e are formed of polyimide films. The first and second metal layers 71b and 71f are formed of aluminum plates.

The second sheet 72 is an urethane foam sheet placed between a lower surface 71n (a second surface) of the second heater 71 and the second holder 75. This second sheet 72 is elastically deformable in a direction of thickness of the second heater 71 (in a vertical direction in FIG. 7).

The second holder 75 is formed in rectangular recessed shape, including a holding part 75c internally holding the second heater 71 and a rectangular annular flange 75b surrounding an open end of the holding part 75c. This flange 75b is formed with a plurality of through holes 75d each allowing a threaded portion 12b of a mounting bolt 12 to pass through as shown in FIG. 10.

The bottom wall 34b of the second housing member 30 is formed with threaded holes 34c in positions corresponding to the through holes 75d of the second heater unit 70 as shown in FIG. 10. Each of the threaded holes 34c is configured to threadably engage with the threaded portion 12b of the mounting bolt 12. In the present embodiment, the threaded portion 12b of the mounting bolt 12 is inserted through the through hole 75d of the flange 75b and tightened in the threaded hole 34d of the bottom wall 34b of the second housing member 30, thereby detachably fixing the second heater unit 70 to the outer surface 34f of the bottom wall 34b of the second housing member 30.

As above, the second heater unit 70 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 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 71. In particular, the second heater unit 70 of the present embodiment is constituted of the second heater 71, the second sheet 72, the second holder 75, and the heat insulating member 78 which are integrally bonded to one another, so that the second heater unit 70 can be handled easily, facilitating a mounting work with respect to the battery pack 50 or other works.

Furthermore, in the second heater unit 70 as with the first heater unit 60, in an original state prior to fixation to the battery pack 50, the total thickness of the second heater 71 and the second sheet 72 is L and the second heater 71 protrudes by a distance ΔL from a contact surface 75h of the flange 75b of the second holder 75 as shown in FIG. 7. The contact surface 75h of the flange 75b is a surface making contact with the outer surface 34f of the bottom 34b of the second housing member 30 when the second heater unit 70 is fixed to the battery pack 50 as shown in FIG. 10.

With this second heater unit 70 is fixed to the outer surface 34f of the bottom 34b of the second housing member 30 as mentioned above, as shown in FIG. 10, the total thickness of the second heater 71 and the second sheet 72 is reduced from L to M (see FIG. 7). At that time, the second sheet 72 is elastically compressed and deformed by the distance ΔL (ΔL=L−M) (see FIG. 7) in the direction of thickness of the second heater 71 (in the vertical direction in FIG. 10). By an elastic force caused by this elastically compressive deformation, an upper surface 71m (a first surface) of the second heater 71 can be held in close contact with the outer surface 35b of the spaced part 35.

Particularly, in the second heater unit 70, the entire second sheet 72 is in contact with the lower surface 71n of the second heater 71. Thus, the entire lower surface 71n of the second heater 71 can be pressed by the elastic force of the second sheet 72, thereby adequately brining the upper surface 71m of the second heater 71 into close contact with the outer surface 35b of the spaced part 35. As a result, no gap is formed between the upper surface 71m of the second heater 71 and the outer surface 35b of the spaced part 35, and therefore the battery pack 50 can be heated properly. Furthermore, the heat of the second heater 71 can appropriately be conducted to the battery pack 50, thereby preventing the temperature of the second heater 71 (part or whole of the second heater 71) itself from excessively increasing.

The first heater 61 and the second heater 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 heater. 61 and the second heater 71, thereby causing them to generate heat.

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

In the heater-equipped battery structure 10 of the present embodiment, as mentioned above, the first heater 61 and the second heater 71 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 heater 61 and the second 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.

As well as the spaced part 35, the space S exists between each of the heaters 61 and 71 and each of the secondary batteries 100. Accordingly, even where the temperatures of the first heater 61 and the second heater 71 abnormally rise due to any failure or malfunction, each secondary battery 100 can be prevented from excessively increasing in temperature.

Furthermore, as mentioned above, the upper surface 61m of the first heater 61 is held in close contact with the outer surface 35b of the spaced part 35 by the elastic force of the first sheet 62. Simultaneously, the upper surface 71m of the second heater 71 is held in close contact with the outer surface 35b of the spaced part 35 by the elastic force of the second sheet 72. The battery pack 50 can therefore be heated appropriately. Furthermore, the heat of the first heater 61 and the second heater 71 can be conducted adequately to the battery pack 50, which can prevent the first heater 61 and the second heater 71 from excessively increasing in temperature.

In the first heater unit 60 of the present embodiment, the first sheet 62 made of urethane foam is used for a sheet placed on the lower surface 61n of the first heater 61. Similarly, the second sheet 72 formed of urethane foam is used for a sheet placed on the lower surface 71n of the second heater 71. Those first and second sheets 62 and 72 formed of urethane foam have heat insulating properties. Accordingly, the heat of the first and second heaters 61 and 71 are unlikely to escape from the lower surfaces 61n and 71n. This configuration therefore allows the heat of the first and second heaters 61 and 71 to be efficiently conducted to the spaced part 35 of the housing case 40.

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 heaters 61 and 71 are unlikely to escape from the lower surfaces 65g and 75g of the holding members 65 and 75.

In the heater-equipped battery structure 10 of the present embodiment having the above configuration, the heat of the first and second heaters 61 and 71 can efficiently be conducted to the spaced part 35 of the housing case 40. Thus, each secondary battery 100 can be heated efficiently.

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. 11, 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.

The present invention may be embodied in other specific forms without departing from the essential characteristics thereof.

In the above embodiment, for example, the battery structure to be heated is exemplified as the battery pack 50 having a plurality of secondary batteries 100 (forty batteries in the embodiment) and the housing case 40 that houses them. 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 such as a lithium ion battery.

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.

Claims

1. A heater unit including: a sheet heater having a first surface and a second surface; and a holding member which holds the heater,the heater unit being arranged to be fixed to a battery structure that includes a power generating element to heat the power generating element by heating a surface of the battery structure to be heated,wherein the heater unit further comprises a sheet placed between the second surface of the heater and the holding member in such a manner as to be deformable in at least a direction of thickness of the heater, andthe sheet can be deformed when the heater unit is fixed to the battery structure, pressing the second surface of the heater to bring the first surface of the heater in close contact with the surface of the battery structure to be heated.

2. The heater unit according to claim 1, wherein the sheet is elastically deformable in the direction of thickness of the heater, andthe sheet can be elastically compressed and deformed in the direction of thickness of the heater when the heater unit is fixed to the battery structure, bringing the first surface of the heater in close contact with the surface of the battery structure to be heated by an elastic force caused by elastically compressive deformation of the sheet.

3. The heater unit according to claim 1, wherein the holding member is arranged to detachably attach the heater unit to the battery structure.

4. The heater unit according to claim 1, wherein the sheet is placed on the entire second surface of the heater.

5. The heater unit according to claim 1, wherein the heater is bonded to the sheet, andthe sheet is bonded to the holding member.

6. The heater unit according to claim 1, wherein the sheet has heat insulating properties.

7. A battery structure with heater, comprising; the heater unit according to claim 1; andthe battery structure including the power generating element and having the surface to be heated;wherein the sheet of the heater unit is deformed to press the second surface of the heater to bring the first surface of the heater into close contact with the surface of the battery structure to be heated.

8. A battery structure with heater, comprising: a battery structure including a power generating element and having a surface to be heated; anda heater unit including: a sheet heater having a first surface and a second surface, anda holding member which holds the heater,the heater unit being fixed to the battery structure to heat the surface of the battery structure to be heated to heat the power generating element,wherein the heater unit further includes a sheet placed between the second surface of the heater and the holding member in such a manner as to be deformable in at least a direction of thickness of the heater, andthe sheet is deformed to press the second surface of the heater to hold the first surface of the heater in close contact with the surface of the battery structure to be heated.

9. The battery structure with heater according to claim 8, wherein the sheet is elastically deformable in the direction of thickness of the heater,the first surface of the heater is held in close contact with the surface of the battery structure to be heated by an elastic force caused by elastically compressive deformation of the sheet.