JP7270414B2 - Temperature sensors, battery modules and battery packs - Google Patents

Description

The present invention relates to temperature sensors, battery modules and battery packs.

2. Description of the Related Art A battery module in which a plurality of batteries are electrically connected is known as a power supply for vehicles, for example, which requires a high output voltage. Generally, a battery module is provided with a battery temperature sensor for detecting the temperature of the battery.

Regarding this battery temperature sensor, for example, Patent Literature 1 discloses a battery temperature sensor having a conductive contact portion in contact with the battery and a measurement portion electrically connected to the contact portion. It is difficult for the battery temperature sensor to accurately detect the temperature unless the contact with the battery, which is the object to be detected, is sufficient. Therefore, in the battery temperature sensor of Patent Document 1, the electrical resistance between the contact portion and the battery is measured by the measurement portion, and the connection state between the battery temperature sensor and the battery is determined based on the measurement result. .

JP 2015-99087 A

In a battery module, an overheating chain can occur in which a battery becomes too hot during use, and the heat is transferred to an adjacent battery, causing the temperature of the adjacent battery to rise too much. In particular, in recent years, the capacity of batteries has been increasing, and the temperature of the batteries tends to increase. In order to prevent this chain of overheating, it is desirable to detect the overheating of the battery, which is the source of the chain, at an early stage.

On the other hand, in a conventional battery module, it was common to attach one or two battery temperature sensors to detect the temperature of a representative battery, thereby monitoring the temperature of the entire battery module. In such a configuration in which battery temperature sensors are provided only for some batteries, it takes time to detect overheating of batteries far from the battery temperature sensors. On the other hand, it is conceivable to quickly detect overheating of each battery by attaching a battery temperature sensor to each battery constituting the battery module. However, in this case, the number of parts increases significantly and the structure of the battery module becomes complicated.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for detecting overheating of a battery at an early stage while suppressing complication of the structure.

One aspect of the invention is a temperature sensor. The temperature sensor includes a substrate thermally connected to the battery, and a first temperature sensing element and a second temperature sensing element mounted on the substrate. The substrate has a first region having a strong thermal connection with the battery and a second region having a weaker thermal connection with the battery than the first region. A first temperature sensing element is mounted in the first area and a second temperature sensing element is mounted in the second area.

Another aspect of the invention is a battery module. This battery module includes a battery stack having a plurality of stacked batteries, and the temperature sensor of the aspect described above.

Yet another aspect of the invention is a battery pack. This battery pack includes the battery module of the aspect described above and a case that accommodates the battery module.

Any combination of the above constituent elements, and conversion of expressions of the present invention between methods, devices, systems, etc. are also effective as aspects of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, overheating of a battery can be detected earlier, suppressing complication of a structure.

1 is an exploded perspective view of a battery module according to Embodiment 1; FIG. 1 is a side view schematically showing a temperature sensor according to Embodiment 1; FIG. It is a perspective view which shows some temperature sensors typically. 1 is a diagram schematically showing a battery pack according to Embodiment 1; FIG. FIG. 10 is a diagram schematically showing a battery pack according to Embodiment 2;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on preferred embodiments with reference to the drawings. The embodiments are illustrative rather than limiting the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention. The same or equivalent constituent elements, members, and processes shown in each drawing are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience in order to facilitate the explanation, and should not be construed as limiting unless otherwise mentioned. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or degree of importance. and other configurations. Also, in each drawing, some of the members that are not important for explaining the embodiments are omitted.

(Embodiment 1)
FIG. 1 is an exploded perspective view of a battery module according to Embodiment 1. FIG. A battery module 1 includes a battery stack 2 , a pair of end plates 4 , a pair of side separators 6 , and a pair of restraining members 8 .

The battery stack 2 has a plurality of batteries 10 and inter-cell separators 12 . Each battery 10 is, for example, a rechargeable secondary battery such as a lithium ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery. Each battery 10 is a so-called prismatic battery, and has a flat rectangular parallelepiped outer can 14 . A substantially rectangular opening (not shown) is provided on one surface of the outer can 14, and an electrode body, an electrolytic solution, and the like are accommodated in the outer can 14 through this opening. A sealing plate 16 is provided at the opening of the outer can 14 to close the opening.

In the sealing plate 16, a positive output terminal 18 is arranged near one end in the longitudinal direction, and a negative output terminal 18 is arranged near the other end. A pair of output terminals 18 are electrically connected to a positive electrode plate and a negative electrode plate, respectively, which constitute an electrode assembly. Hereinafter, the positive output terminal 18 will be referred to as a positive terminal 18a, and the negative output terminal 18 will be referred to as a negative terminal 18b. Moreover, when it is not necessary to distinguish the polarity of the output terminal 18 , the positive terminal 18 a and the negative terminal 18 b are collectively referred to as the output terminal 18 .

The outer can 14, the sealing plate 16, and the output terminal 18 are conductors, and are made of metal, for example. The sealing plate 16 and the opening of the outer can 14 are joined by laser welding, for example. Each output terminal 18 is inserted through a through hole (not shown) formed in the sealing plate 16 . An insulating sealing member (not shown) is interposed between each output terminal 18 and each through hole.

In the description of the present embodiment, for convenience, the sealing plate 16 is the top surface of the battery 10 and the bottom surface of the outer can 14 facing the sealing plate 16 is the bottom surface of the battery 10 . Battery 10 also has two major surfaces connecting the top and bottom surfaces. This main surface is the surface with the largest area among the six surfaces of battery 10 . Also, the main surface is a long side surface connected to the long sides of the upper surface and the lower surface. The remaining two surfaces other than the upper surface, the lower surface and the two main surfaces are side surfaces of the battery 10 . The side faces are a pair of short sides connected to the short sides of the top and bottom faces.

Further, for convenience, in the battery stack 2, the surface on the upper surface side of the battery 10 is the upper surface of the battery stack 2, the surface on the lower surface of the battery 10 is the lower surface of the battery stack 2, and the side surface of the battery 10 is the battery It is the side surface of the laminate 2 . These directions and positions are defined for convenience. Therefore, for example, the portion defined as the upper surface in the present invention does not necessarily mean that it is positioned above the portion defined as the lower surface.

A valve portion 20 is provided between the pair of output terminals 18 on the sealing plate 16 . The valve portion 20 is also called a safety valve, and is a mechanism for releasing gas inside the battery 10 . The valve portion 20 is configured to open when the internal pressure of the armored can 14 rises to a predetermined value or more to release the internal gas. The valve portion 20 is composed of, for example, a thin portion thinner than the other portion provided in a portion of the sealing plate 16 and a linear groove formed on the surface of the thin portion. In this configuration, when the internal pressure of the outer can 14 rises, the valve is opened by tearing the thin portion starting from the groove.

Each battery 10 also has an insulating film (not shown). The insulating film is, for example, a cylindrical shrink tube, which is heated after the outer can 14 is passed through. As a result, the insulating film shrinks and covers the two main surfaces, the two side surfaces and the bottom surface of the outer can 14 . The insulating film can suppress short circuits between the adjacent batteries 10 or between the batteries 10 and the end plate 4 or the restraining member 8 .

A plurality of batteries 10 are stacked at predetermined intervals such that the main surfaces of adjacent batteries 10 face each other. In addition, "lamination" means arranging a plurality of members in one arbitrary direction. Therefore, the stacking of the batteries 10 also includes arranging the plurality of batteries 10 horizontally. Each battery 10 is arranged so that the output terminals 18 face the same direction. In this embodiment, the batteries 10 are horizontally stacked. Therefore, the stacking direction X of the batteries 10 is the horizontally extending direction. Each battery 10 is arranged so that the output terminal 18 faces upward in the vertical direction. Hereinafter, a horizontal direction perpendicular to the stacking direction X will be referred to as a horizontal direction Y, and a direction perpendicular to the stacking direction X and the horizontal direction Y will be referred to as a vertical direction Z, as appropriate.

The inter-cell separator 12 is also called an insulating spacer, and is made of, for example, an insulating resin sheet. Examples of the resin forming the inter-cell separator 12 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE). The inter-cell separator 12 is placed between two adjacent batteries 10 to electrically insulate the two batteries 10 .

The battery stack 2 is sandwiched between a pair of end plates 4 . A pair of end plates 4 are arranged at both ends of the battery stack 2 in the stacking direction X. As shown in FIG. The pair of end plates 4 are adjacent to the batteries 10 positioned at both ends in the stacking direction X with inter-cell separators 12 interposed therebetween. Each end plate 4 is a metal plate made of metal such as iron, stainless steel, and aluminum. By interposing the inter-cell separator 12 between the end plate 4 and the battery 10, both are insulated.

Each end plate 4 has fastening holes 4a on two surfaces facing the horizontal direction Y. As shown in FIG. In the present embodiment, three fastening holes 4a are arranged in the vertical direction Z at predetermined intervals. A surface on which the fastening hole 4a is provided faces a flat portion 8a of the restraining member 8, which will be described later.

The side separator 6 is arranged between the binding member 8 and the battery stack 2 to electrically insulate them. In this embodiment, a pair of side separators 6 are arranged in the horizontal direction Y. As shown in FIG. Each side separator 6 is elongated in the stacking direction X of the batteries 10 . A battery stack 2 is arranged between a pair of side separators 6 . Each side separator 6 is made of, for example, an insulating resin. Similar to the inter-cell separator 12, thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE) can be used as the resin constituting the side separator 6. are exemplified.

The side separator 6 of this embodiment has a first portion 6a, a second portion 6b, and a third portion 6c. The first portion 6 a has a rectangular flat plate shape and extends in the stacking direction X along the side surface of the battery stack 2 . The second portion 6b has a strip shape extending in the stacking direction X and protrudes toward the battery stack 2 from the upper end of the first portion 6a. The third portion 6c has a strip shape extending in the stacking direction X and protrudes toward the battery stack 2 from the lower end of the first portion 6a.

The restraint member 8 is also called a bind bar and is a long member extending in the stacking direction X. As shown in FIG. The restraining member 8 is arranged so as to face the side surface of the battery stack 2 . In this embodiment, a pair of restraining members 8 are arranged in the horizontal direction Y. As shown in FIG. Each restraining member 8 is made of metal. Examples of the metal forming the restraining member 8 include iron and stainless steel. A battery stack 2 , a pair of end plates 4 and a pair of side separators 6 are arranged between the pair of restraining members 8 .

The restraining member 8 of this embodiment has a flat portion 8a and a pair of arm portions 8b. The planar portion 8 a is rectangular and extends in the stacking direction X along the side surface of the battery stack 2 . The pair of arm portions 8b protrude toward the battery stack 2 from both ends of the planar portion 8a in the vertical direction Z. As shown in FIG. That is, one arm portion 8b protrudes from the upper side of the planar portion 8a toward the battery stack 2 side, and the other arm portion 8b protrudes from the lower side of the planar portion 8a toward the battery stack 2 side. The battery stack 2 and the side separator 6 are arranged between the pair of arm portions 8b.

A contact plate 22 is fixed by welding or the like to a region of the flat portion 8a facing each end plate 4 . The contact plate 22 is a member elongated in the vertical direction Z. As shown in FIG. The contact plate 22 is provided with a through hole 22a penetrating through the contact plate 22 in the horizontal direction Y at a position corresponding to the fastening hole 4a of the end plate 4 . Further, the plane portion 8a has a through hole 8c penetrating the plane portion 8a in the horizontal direction Y at a position corresponding to the through hole 22a of the contact plate 22. As shown in FIG.

The plurality of batteries 10 are sandwiched in the stacking direction X by engaging the pair of end plates 4 with the flat portions 8a of the restraining members 8 . Specifically, a plurality of batteries 10 and a plurality of inter-cell separators 12 are alternately arranged to form a battery stack 2, and the battery stack 2 is laminated by a pair of end plates 4 with the inter-cell separators 12 interposed therebetween. sandwiched in the X direction. In this state, the battery stack 2 is sandwiched in the horizontal direction Y between the pair of side separators 6 . Further, a pair of restraint members 8 sandwich the entire structure in the horizontal direction Y from the outside of the pair of side separators 6 .

The pair of end plates 4 and the pair of restraining members 8 are aligned with each other such that the fastening holes 4a, the through holes 22a and the through holes 8c overlap. A fastening member 24 such as a screw is inserted through the through hole 8c and the through hole 22a and screwed into the fastening hole 4a. Thereby, the pair of end plates 4 and the pair of restraining members 8 are fixed. The plurality of batteries 10 are tightened and restrained in the stacking direction X by engaging the pair of end plates 4 and the pair of restraining members 8 . Thereby, each battery 10 is positioned in the stacking direction X. As shown in FIG. Moreover, the plurality of batteries 10 are sandwiched in the vertical direction Z by the pair of arm portions 8b. Thereby, each battery 10 is positioned in the vertical direction Z. FIG.

With the battery stack 2 sandwiched between the pair of arms 8b in the vertical direction Z, the second portion 6b of the side separator 6 is interposed between the upper arm 8b and the battery stack 2, and the lower side A third portion 6c of the side separator 6 is interposed between the arm portion 8b of the battery stack 2 and the battery stack 2. As shown in FIG. Thereby, each arm portion 8b and the battery stack 2 are electrically insulated.

As an example, after the assembly is completed, a bus bar 60 (see FIG. 4) is attached to the output terminal 18 of each battery 10 to electrically connect the output terminals 18 of the plurality of batteries 10 together. For example, the busbar is fixed to the output terminal 18 by welding.

At both end portions of the restraining member 8 in the stacking direction X, fixing portions 26 are arranged. The battery module 1 is fixed to the fixing target by the fixing portion 26 . An object to be fixed is, for example, a case 54 of a battery pack 52 to be described later. The fixed portion 26 has a through hole 26a through which a fastening member (not shown) is inserted. The object to be fixed has a fastening hole (not shown), and the fastening hole and the through hole 26a are overlapped, and the fastening member is inserted through the hole, whereby the battery module 1 is fixed to the object to be fixed. Note that the fixing portion 26 may be fixed to the fixing target by other methods such as welding.

A busbar plate (not shown) may be mounted on the upper surface of the battery stack 2 . The busbar plate is a plate material that covers the upper surfaces of the plurality of batteries 10 and supports the busbars. Also, a top cover (not shown) may be mounted on the upper surface of the busbar plate. The top cover can prevent condensed water, dust, and the like from contacting the output terminal 18 of the battery 10, the valve portion 20, the bus bar, and the like.

The battery module 1 also includes a temperature sensor 28 . The temperature sensor 28 is thermally connected to the predetermined battery 10, that is, heat exchange is possible. In this embodiment, battery module 1 includes one temperature sensor 28 . The temperature sensor 28 is fixed to the sealing plate 16 of the predetermined battery 10 .

FIG. 2 is a side view schematically showing temperature sensor 28 according to the first embodiment. FIG. 3 is a perspective view schematically showing part of the temperature sensor 28. As shown in FIG. The temperature sensor 28 includes a substrate 30, a first temperature detection element 32, a second temperature detection element 34, a first metal plate 36, a second metal plate 38, a support portion 40, an adhesive layer 42, an adhesive a layer 50;

The substrate 30 is a member on which the first temperature detection element 32 and the second temperature detection element 34 are mounted. The substrate 30 of this embodiment is a flexible printed circuit board, and is formed of a flexible and insulating material such as polyimide. On one surface of the substrate 30, lands (not shown) to which the first temperature detection element 32 and the second temperature detection element 34 are electrically connected and wiring (not shown) extending from the lands are laid. there is A lead wire 44 is connected to the substrate 30 by soldering or the like. The lead wire 44 is connected to an external battery ECU (not shown) or the like. Information (such as voltage) regarding the temperature detected by the first temperature detection element 32 and the second temperature detection element 34 is sent to the battery ECU via the lead wire 44 . The battery ECU can determine abnormality of each battery 10 based on the detection results of the first temperature detection element 32 and the second temperature detection element 34 . As an example, when the battery ECU determines that the battery 10 is abnormal, it transmits a signal to another control circuit or the like for controlling the vehicle.

Substrate 30 is laminated on one main surface of second metal plate 38 . The second metal plate 38 is made of a highly thermally conductive metal material such as aluminum. An adhesive layer 42 is interposed between the substrate 30 and the second metal plate 38 , and the substrate 30 is fixed to the second metal plate 38 by the adhesive layer 42 . The adhesive layer 42 is composed of, for example, a double-sided adhesive tape having heat resistance and thermal conductivity.

The other main surface of second metal plate 38 (the main surface opposite to the side on which substrate 30 is laminated) is fixed to battery 10 by adhesion or the like. A second metal plate 38 is disposed between the substrate 30 and the battery 10 and thermally connected to the substrate 30 and the battery 10 . Therefore, substrate 30 is thermally connected to battery 10 via second metal plate 38 and adhesive layer 42 . By supporting the substrate 30 with the second metal plate 38, the rigidity of the temperature sensor 28 can be increased.

The substrate 30 has a first region 30a having a strong thermal connection with the battery 10 and a second region 30b having a weaker thermal connection with the battery 10 than the first region 30a. That is, the amount of heat transferred between the battery 10 and the first region 30a (the amount of heat transferred from the battery 10 to the first region 30a or from the first region 30a to the battery 10 per unit time and unit volume) is the battery 10 and the second region 30b (the amount of heat transferred from the battery 10 to the second region 30b or from the second region 30b to the battery 10 per unit time and unit volume).

The second region 30b of the present embodiment is arranged at a position farther from the battery 10 than the first region 30a. As a result, the second region 30b has a weaker thermal connection with the battery 10 than the first region 30a. Further, the substrate 30 of the present embodiment has a flat portion 46 extending along the sealing plate 16 of the battery 10 and a protruding portion 48 protruding from the flat portion 46 in a direction away from the battery 10 . The first region 30 a is arranged on the flat portion 46 and the second region 30 b is arranged on the protruding portion 48 .

Projection 48 is further away from battery 10 than flat portion 46 . Therefore, the projecting portion 48 transfers less heat from the battery 10 than the flat portion 46 . Therefore, by arranging the first region 30a on the flat portion 46 and arranging the second region 30b on the projecting portion 48, the strength of the thermal connection between the first region 30a and the second region 30b with the battery 10 can be increased. can be different.

Moreover, the projecting portion 48 of the present embodiment is configured by a bent portion of the substrate 30 . Since the substrate 30 is a flexible printed circuit board, it can be easily bent. Therefore, the projecting portion 48 can be easily formed by cutting a portion of the substrate 30, peeling this portion from the adhesive layer 42 and bending it, or by warping it. On the other hand, flat portion 46 is fixed to the main surface of second metal plate 38 by adhesive layer 42 .

The first temperature sensing element 32 and the second temperature sensing element 34 sense temperature. The temperature to be detected by the first temperature detection element 32 is the temperature of the battery 10 , and the temperature to be detected by the second temperature detection element 34 is the ambient temperature around the battery 10 . In this embodiment, each of the first temperature detection element 32 and the second temperature detection element 34 is composed of a chip-type thermistor. The first temperature detection element 32 and the second temperature detection element 34 may be thermocouples or the like, or may be of a bead type or the like.

When the battery 10 is overheated (thermal runaway), high-temperature gas is ejected from the valve portion 20 . Therefore, by detecting the ambient temperature around the battery 10 with the second temperature detection element 34, the ejection of gas from the battery 10 can be detected. That is, overheating of the battery 10 can be detected. The temperature of the gas ejected from the valve portion 20 is a high temperature of nearly 1000.degree. Therefore, an element having a lower detection resolution than the first temperature detection element 32 that detects the temperature of the battery 10 can be used as the second temperature detection element 34 . By adopting an element with a resolution lower than that of the first temperature detection element 32 for the second temperature detection element 34, the cost of the temperature sensor 28 and thus the battery module 1 can be reduced.

The first temperature sensing element 32 is mounted in the first area 30a and the second temperature sensing element 34 is mounted in the second area 30b. Therefore, the second temperature sensing element 34 is arranged at a position farther from the battery 10 than the first temperature sensing element 32 is. The first temperature sensing element 32 and the second temperature sensing element 34 may be sealed with a sealing resin (not shown). In this case, the sealing resin preferably has thermal conductivity.

The first region 30 a is provided in the flat portion 46 and has a strong thermal connection with the battery 10 . Therefore, by mounting the first temperature detection element 32 in the first region 30 a , the temperature of the battery 10 can be preferably detected by the first temperature detection element 32 . On the other hand, the second region 30b is provided in the projecting portion 48 and has a weak thermal connection with the battery 10 . Therefore, by mounting the second temperature detection element 34 in the second region 30b, the thermal influence of the battery 10 on the second temperature detection element 34 can be reduced. Therefore, the ambient temperature around the battery 10 can be preferably detected by the second temperature detection element 34 .

Also, the flat portion 46 is fixed to the second metal plate 38 via the adhesive layer 42 . The second metal plate 38 has a larger heat capacity than the substrate 30 and easily stores the heat of the battery 10 . Therefore, detection of the battery temperature by the first temperature detection element 32 can be made more stable. Further, by fixing the flat portion 46 to the second metal plate 38, the flatness of the flat portion 46 can be improved. Thereby, the heat of the battery 10 can be stably conducted to the first temperature detection element 32 . Therefore, the detection accuracy of the battery temperature by the first temperature detection element 32 can be improved.

A first metal plate 36 is thermally connected to the surface of the projecting portion 48 opposite to the side on which the second temperature sensing element 34 is mounted. In this embodiment, the adhesive layer 50 fixes the first metal plate 36 to the projecting portion 48 . The first metal plate 36 can be made of the same material as the second metal plate 38 . Adhesive layer 50 can be composed of the same material as adhesive layer 42 . The first metal plate 36 has a larger heat capacity than the substrate 30 and easily stores the heat of the atmosphere around the battery 10 . Therefore, the detection of the ambient temperature by the second temperature detection element 34 can be made more stable.

The support portion 40 holds the bent portion of the substrate 30 , that is, the bent state of the projecting portion 48 . The support portion 40 has a base portion 40a and a detent portion 40b. The base portion 40 a extends along the second metal plate 38 and is fixed to the second metal plate 38 via the adhesive layer 42 . The detent portion 40b protrudes from the base portion 40a in a direction away from the battery 10 . The support portion 40 is arranged at the confluence of the protruding portion 48 and the adhesive layer 42 . In this state, the detent portion 40b hits the surface of the projecting portion 48 facing the second metal plate 38 before being bent. As a result, it is possible to suppress the warped protruding portion 48 from returning to its original position, that is, the protruding portion 48 from being displaced toward the second metal plate 38 with the connecting portion to the flat portion 46 as a fulcrum.

Next, battery pack 52 according to the present embodiment will be described. FIG. 4 is a diagram schematically showing a battery pack according to Embodiment 1. FIG. In FIG. 4, illustration of the inter-cell separator 12, the end plate 4, the side separator 6, and the binding member 8 is omitted. Battery module 1 of the present embodiment is accommodated in case 54 to form battery pack 52 . That is, battery pack 52 of the present embodiment includes battery module 1 and case 54 that accommodates battery module 1 . Battery module 1 is fixed to case 54 by fixing portion 26 (see FIG. 1). The case 54 is fixed to a fixed object (not shown) such as a vehicle body by a predetermined fixing mechanism (not shown).

Battery pack 52 also accommodates a battery module different from battery module 1 according to the present embodiment. In the following description, for convenience, the battery module 1 according to this embodiment will be referred to as a first battery module 1a, and a battery module different from the first battery module 1a will be referred to as a second battery module 1b. Second battery module 1b includes a temperature sensor different from temperature sensor 28 according to the present embodiment. In the following description, for convenience, the temperature sensor 28 according to this embodiment will be referred to as a first temperature sensor 28a, and a temperature sensor different from the first temperature sensor 28a will be referred to as a second temperature sensor 28b.

The second temperature sensor 28b differs from the first temperature sensor 28a in that it has the first temperature detection element 32 and does not have the second temperature detection element 34 . That is, the second temperature sensor 28b is a conventional battery temperature sensor. Also, the second battery module 1b is a conventional battery module provided with a second temperature sensor 28b in place of the first temperature sensor 28a.

In both the first battery module 1a and the second battery module 1b, the battery stack 2 includes a battery unit 58 in which at least two batteries 10 are connected in parallel. Specifically, in each battery module, a plurality of batteries 10 are grouped into a plurality of battery units 58 each composed of a predetermined number of batteries 10 . In each battery unit 58 , the batteries 10 are connected in parallel with each other via a bus bar 60 . Adjacent battery units 58 are connected in series with busbars 60 . The busbar 60 is a substantially strip-shaped member made of metal such as copper or aluminum.

In the example shown in FIG. 4, in each battery module, three battery units 58 are formed by stacking four batteries 10 such that the output terminals 18 of the same polarity are adjacent to each other. The three battery units 58 are stacked such that the output terminals 18 of different polarities of adjacent battery units 58 are adjacent to each other. A bus bar 60 is joined to each output terminal 18 . Thereby, the batteries 10 in each battery unit 58 are connected in parallel, and the battery units 58 are connected in series. In addition, in the second battery module 1b, all the batteries 10 may be connected in series.

The battery pack 52 also includes an exhaust port 56 that communicates the inside and outside of the case 54 . Battery pack 52 of the present embodiment includes two exhaust ports 56 . The case 54 has a rectangular shape in plan view, and the two exhaust ports 56 are arranged approximately diagonally. When gas blows out from any of the batteries 10 of the battery modules 1 accommodated in the case 54 , this gas is discharged to the outside of the case 54 through the exhaust port 56 .

First battery module 1 a and second battery module 1 b are arranged in case 54 . In the example shown in FIG. 4, two first battery modules 1a and six second battery modules 1b are arranged in a matrix of 2 rows and 4 columns. In the arrangement of the battery modules, the first battery module 1a is arranged at the position closest to the exhaust port 56 . In the present embodiment, one first battery module 1 a is arranged closest to one exhaust port 56 , and the other first battery module 1 a is arranged closest to the other exhaust port 56 .

This facilitates the design of arranging the first temperature sensor 28a in the vicinity of the exhaust port 56. FIG. Even when gas is ejected from any battery 10 , the ejected gas is exhausted to the outside of the case 54 through the exhaust port 56 . Therefore, by arranging the first temperature sensor 28a in the vicinity of the exhaust port 56, it becomes possible to more reliably detect that any one of the batteries 10 in the battery pack 52 is overheated.

Further, in the present embodiment, the first temperature sensor 28a is attached to the battery unit 58 closest to the exhaust port 56 in the first battery module 1a. Furthermore, a first temperature sensor 28 a is attached to the battery 10 closest to the exhaust port 56 . As a result, it is possible to more reliably detect that any one of the batteries 10 in the battery pack 52 is overheated. In addition, in the second battery module 1b, the position where the second temperature sensor 28b is provided is not particularly limited. In this embodiment, a second temperature sensor 28b is attached to the battery 10 in the center.

As described above, temperature sensor 28 (first temperature sensor 28a) according to the present embodiment includes substrate 30 thermally connected to battery 10, first temperature detection element 32 mounted on substrate 30, and and a second temperature sensing element 34 . The substrate 30 has a first region 30a having a strong thermal connection with the battery 10 and a second region 30b having a weaker thermal connection with the battery 10 than the first region 30a. The first temperature sensing element 32 is mounted in the first area 30a, and the second temperature sensing element 34 is mounted in the second area 30b.

As a method for early detection of overheating of the batteries 10 far from the battery temperature sensor while suppressing complication of the structure of the battery module 1 due to attaching the battery temperature sensor to each battery 10, the overheated battery 10 spouts out. A temperature sensor for a battery may be used to detect an increase in ambient temperature due to gas. However, the battery temperature sensor is connected to the battery 10 having a large heat capacity. For this reason, the battery temperature sensor is not easily affected by the ambient temperature, and may not be able to accurately detect an increase in the ambient temperature due to gas ejected from the battery 10 .

In contrast, in the temperature sensor 28 of the present embodiment, the first temperature detection element 32 is mounted in the first region 30a having relatively strong thermal connection with the battery 10, and the thermal connection with the battery 10 is reduced. A second temperature sensing element 34 is mounted in the second region 30b where the voltage is relatively weak. Thereby, the detection sensitivity of the second temperature detection element 34 to changes in the ambient temperature around the battery 10 can be enhanced. Therefore, the temperature of the battery 10 can be detected by the first temperature detection element 32 and the ambient temperature around the battery 10 can be detected by the second temperature detection element 34 . Therefore, according to temperature sensor 28 according to the present embodiment, overheating of each battery 10 can be detected earlier while suppressing complication of the structure of battery module 1 .

Moreover, since the two temperature detection elements are mounted on the same substrate 30, the number of parts and the cost of the temperature sensor 28 can be reduced compared to mounting them on separate substrates. Also, the temperature sensor 28 and thus the battery module 1 can be miniaturized. Furthermore, since the wiring of each temperature detection element can be easily routed, the complication of the structure of the temperature sensor 28 can be further suppressed.

Further, in the present embodiment, the second region 30b is arranged at a position farther from the battery 10 than the first region 30a. Therefore, the second temperature sensing element 34 is arranged at a position farther from the battery 10 than the first temperature sensing element 32 is. Thereby, heat transfer from the second temperature detection element 34 to the battery 10 can be further suppressed. Therefore, the second temperature detection element 34 can detect the ambient temperature around the battery 10 more accurately or more reliably.

Further, the substrate 30 has a flat portion 46 extending along the battery 10 and a protruding portion 48 protruding from the flat portion 46 in a direction away from the battery 10 . The first region 30 a is arranged on the flat portion 46 and the second region 30 b is arranged on the protruding portion 48 . This makes it possible to weaken the thermal connection between the second temperature sensing element 34 and the battery 10 with a simple structure. Therefore, complication of the structure of the battery module 1 can be further suppressed.

Moreover, the projecting portion 48 of the present embodiment is configured by a bent portion of the substrate 30 . As a result, the thermal connection between the second temperature sensing element 34 and the battery 10 can be weakened with a simple structure without increasing the number of parts. Therefore, complication of the structure of the battery module 1 can be further suppressed.

Also, the substrate 30 is a flexible printed circuit board. The temperature sensor 28 includes a support portion 40 that holds the bent portion of the substrate 30 in a bent state. As a result, the weakened thermal connection between the second temperature detection element 34 and the battery 10 can be more stably maintained.

The temperature sensor 28 also includes a first metal plate 36 thermally connected to the surface of the projecting portion 48 opposite to the side on which the second temperature sensing element 34 is mounted. As a result, detection of the ambient temperature by the second temperature detection element 34 can be made more stable. Temperature sensor 28 also includes a second metal plate 38 disposed between and thermally connected to substrate 30 and battery 10 . Thereby, detection of the battery temperature by the first temperature detection element 32 can be made more stable. Also, the rigidity of the temperature sensor 28 can be increased. In addition, the flatness of the flat portion 46 can be improved, so that detection of the battery temperature by the first temperature detection element 32 can be more stabilized.

Moreover, the battery module 1 according to the present embodiment includes a battery stack 2 having a plurality of stacked batteries 10, and a temperature sensor 28 (first temperature sensor 28a) according to the present embodiment. By installing the temperature sensor 28 that can detect overheating of each battery 10 at an early stage with a simple structure in the battery stack 2, the structure of the battery module 1 is suppressed from being complicated and the cost is increased, and the safety is high. A battery module 1 can be obtained.

The battery stack 2 also includes a battery unit 58 in which at least two batteries 10 are connected in parallel. When all the batteries 10 in the battery stack 2 are connected in series, when any battery 10 in the battery stack 2 overheats, the valve portion 20 operates and the voltage of the battery 10 drops. Therefore, overheating of each battery 10 can also be detected based on the voltage change of the overheated battery 10 .

On the other hand, when the battery stack 2 includes battery units 58 in which the batteries 10 are connected in parallel, the voltages of the batteries 10 constituting the battery unit 58 are averaged. Therefore, even if one of the batteries 10 in the battery unit 58 overheats and the voltage drops, the voltage drop of the overheated battery 10 is suppressed by the voltage of the normal battery 10 in the battery unit 58 . Therefore, it is difficult to accurately detect overheating of each battery 10 based on the detected voltage. On the other hand, by installing the temperature sensor 28 of the present embodiment in the battery stack 2, even in the battery module 1 including the battery unit 58 in which the batteries 10 are connected in parallel, overheating of each battery 10 can be detected with high accuracy. can be detected. It should be noted that the installation of the temperature sensor 28 of the present embodiment is beneficial in that overheating of the batteries 10 can be detected more accurately even in a battery module in which all the batteries 10 are connected in series.

Further, battery pack 52 according to the present embodiment includes battery module 1 (first battery module 1a) according to the present embodiment and case 54 that accommodates battery module 1 .

Further, the battery pack 52 includes a second battery module 1b including a second temperature sensor 28b that has the first temperature detection element 32 but does not have the second temperature detection element 34, and an exhaust port 56 that communicates the inside and outside of the case 54. , provided. A first battery module 1 a and a second battery module 1 b , which are battery modules 1 according to the present embodiment, are arranged in a case 54 . At that time, the first battery module 1a is arranged at the position closest to the exhaust port 56 in the arrangement of the battery modules.

This facilitates the design of arranging the first temperature sensor 28a, which is the temperature sensor 28 of the present embodiment, in the vicinity of the exhaust port 56. FIG. As a result, even if any of the batteries 10 is overheated, it can be detected more reliably that any of the batteries 10 in the case 54 is overheated. Moreover, since overheating of all the batteries 10 in the battery pack 52 can be detected with a smaller number of first temperature sensors 28a, the cost of the battery pack 52 can be reduced.

(Embodiment 2)
In the battery pack according to Embodiment 2, first battery module 1a and second battery module 1b have the same structure except for the type of temperature sensor, and the arrangement of first battery module 1a is not limited. It has a configuration common to that of the first embodiment. Hereinafter, the battery pack 52 according to the present embodiment will be described with a focus on the configuration different from that of the first embodiment, and the common configuration will be briefly described or omitted. FIG. 5 is a diagram schematically showing a battery pack according to Embodiment 2. FIG. In FIG. 5, illustration of the inter-cell separator 12, the end plate 4, the side separator 6, and the binding member 8 is omitted.

Battery pack 52 of the present embodiment includes first battery module 1a, second battery module 1b, and case 54 that accommodates first battery module 1a and second battery module 1b. The first battery module 1a includes the first temperature sensor 28a according to the first embodiment. The second battery module 1b includes a second temperature sensor 28b separate from the first temperature sensor 28a. The second temperature sensor 28b differs from the first temperature sensor 28a only in that it has a first temperature detection element 32 and does not have a second temperature detection element 34 . That is, the second temperature sensor 28b is a conventional battery temperature sensor. Further, the second battery module 1b differs from the first battery module 1a only in that it includes a second temperature sensor 28b instead of the first temperature sensor 28a. That is, the second battery module 1b is a conventional battery module.

In the present embodiment, the arrangement of the first temperature sensors 28a in the first battery module 1a is the same as the arrangement of the second temperature sensors 28b in the second battery module 1b. In the example shown in FIG. 5, a temperature sensor is attached to the central battery 10 in any battery module. This allows the first battery module 1a and the second battery module 1b to have substantially the same structure except for the type of temperature sensor.

When the remaining space in the case 54 is small enough to be filled with the gas ejected from the battery 10, the rise in the ambient temperature due to the gas ejected from the battery 10 can be detected regardless of the position of the first temperature sensor 28a. can be done. Therefore, the first battery module 1 a and the second battery module 1 b can be freely arranged within the case 54 . Moreover, if at least one first battery module 1a is accommodated in the case 54, overheating of all the batteries 10 in the case 54 can be detected. The “remaining space” is an area excluding an area in which objects such as the first battery module 1a and the second battery module 1b exist in the case 54 .

In this case, by making the first battery module 1a and the second battery module 1b substantially identical in structure, it is possible to distinguish between the first battery module 1a and the second battery module 1b when the battery pack 52 is assembled. They can be arranged within the case 54 without distinction. Thereby, the assembly work of the battery pack 52 can be simplified. The "substantially the same" means that the elements that affect the assembly of the battery pack 52, such as the size of the battery module (the number of batteries 10 that constitute it), the size of each battery 10, the arrangement of wiring, etc., are the same. It means that there is

The embodiments of the present invention have been described in detail above. The above-described embodiments merely show specific examples for carrying out the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of constituent elements are possible without departing from the spirit of the invention defined in the claims. is possible. A new embodiment to which a design change has been added has the effects of the combined embodiment and modifications. In the above-described embodiments, the content that allows such design changes is emphasized by adding notations such as "in this embodiment" and "in this embodiment". Design changes are allowed even if there is no content. Any combination of components included in each embodiment is also effective as an aspect of the present invention. The hatching attached to the cross section of the drawing does not limit the material of the hatched object.

In the embodiment, by providing the second region 30b in the projecting portion 48, the thermal connection between the second region 30b and the battery 10 is weaker than the thermal connection between the first region 30a and the battery 10. . However, it is not particularly limited to this configuration, and for example, a method such as providing the second region 30b in the flat portion 46 and interposing a heat insulating material between the second region 30b and the battery 10 can also be used. The thermal connection with the battery 10 can be made different between the first region 30a and the first region 30a.

The number of batteries 10 and the number of battery units 58 included in first battery module 1a and second battery module 1b are not particularly limited. The number of batteries 10 constituting the battery unit 58 is also not particularly limited. Moreover, the structure of the first battery module 1a is not particularly limited except that it includes the first temperature sensor 28a. For example, the fastening structure between end plate 4 and restraint member 8 and the fixing structure between battery module 1 and case 54 are not particularly limited. The side separator 6 may be omitted. Battery 10 may be cylindrical or the like.

Reference Signs List 1 battery module 1a first battery module 1b second battery module 2 battery stack 10 battery 28 temperature sensor 28a first temperature sensor 28b second temperature sensor 30 substrate 30a first region 30b second 2 regions, 32 first temperature detection element, 34 second temperature detection element, 36 first metal plate, 38 second metal plate, 40 support portion, 46 flat portion, 48 protrusion, 52 battery pack, 54 case, 56 exhaust mouth, 58 battery unit;

Claims (10)

a substrate thermally connected to the battery;
a first temperature sensing element and a second temperature sensing element mounted on the substrate;
The substrate has a first region having a strong thermal connection with the battery and a second region having a weaker thermal connection with the battery than the first region,
The first temperature sensing element is mounted in the first region, the second temperature sensing element is mounted in the second region ,
the substrate has a flat portion extending along the battery and a protruding portion protruding from the flat portion in a direction away from the battery;
The temperature sensor , wherein the first area is located on the flat portion and the second area is located on the protruding portion . 2. The temperature sensor according to claim 1 , wherein the projecting portion is formed by a bent portion of the substrate. The substrate is a flexible printed circuit board,
3. The temperature sensor according to claim 2 , wherein the temperature sensor includes a support portion that holds the folded state of the folded portion. 4. The temperature sensor according to claim 2, further comprising a first metal plate thermally connected to a surface of the projecting portion opposite to the side on which the second temperature sensing element is mounted. a substrate thermally connected to the battery;
a first temperature sensing element and a second temperature sensing element mounted on the substrate;
The substrate has a first region having a strong thermal connection with the battery and a second region having a weaker thermal connection with the battery than the first region,
The first temperature sensing element is mounted in the first region, the second temperature sensing element is mounted in the second region,
A temperature sensor comprising a second metal plate disposed between the substrate and the battery and thermally connected to the substrate and the battery. a battery stack having a plurality of stacked batteries;
A battery module comprising the temperature sensor according to any one of claims 1 to 5 . 7. The battery module according to claim 6 , wherein the battery stack includes a battery unit in which at least two batteries are connected in parallel. a battery module according to claim 6 or 7 ;
A battery pack comprising: a case that houses the battery module. The battery pack includes a second battery module different from the first battery module, which is the battery module according to claim 6 or 7 , and an exhaust port that communicates the inside and outside of the case,
The second battery module is a second temperature sensor that is different from the first temperature sensor, which is the temperature sensor according to any one of claims 1 to 7, and has the first temperature detection element. 2 A second temperature sensor that does not have a temperature sensing element,
9. The battery pack according to claim 8 , wherein said first battery module and said second battery module are arranged in said case, and said first battery module is arranged at a position closest to said exhaust port in the arrangement of battery modules. . The battery pack comprises a second battery module different from the first battery module, which is the battery module according to claim 6 or 7 ,
The second battery module is a second temperature sensor that is different from the first temperature sensor, which is the temperature sensor according to any one of claims 1 to 7, and has the first temperature detection element. 2 A second temperature sensor that does not have a temperature sensing element,
9. The battery pack according to claim 8 , wherein the arrangement of the first temperature sensor in the first battery module and the arrangement of the second temperature sensor in the second battery module are the same.

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