CN219714594U - Air pressure detection device and single battery - Google Patents

Abstract

The utility model relates to a gas pressure detection device and a single battery, wherein the gas pressure detection device is applied to a battery to be detected, the battery to be detected comprises a liquid injection port, and the gas pressure detection device comprises: the air duct is provided with a first end and a second end which are opposite, and the first end is used for being connected with the liquid injection port; the first sealant layer is covered on the outer peripheral side of the air duct; the sleeve is sleeved on the outer peripheral side of the air duct and is positioned outside the first sealing rubber layer; and the pressure detection piece is communicated with the second end and is used for detecting the internal pressure of the battery to be detected. The utility model can prevent cracking between the adhesive and the sealing position, and improve the success rate of the test, thereby smoothly evaluating the gas production risk of the battery.

Description

Air pressure detection device and single battery

Technical Field

The utility model relates to the technical field of battery air pressure detection, in particular to an air pressure detection device and a single battery.

Background

In the service process of the battery, internal side reaction produces gas, and when the gas production amount is large, the safety risk exists, so that the gas production performance of the battery internal electric core needs to be analyzed to check the risk.

At present, the gas production risk of the battery cell is generally evaluated by establishing a gas production prediction model, and the premise of establishing the gas production model is that a set of on-line gas production test method exists. In the current industry, the on-line test of the internal pressure of the battery is generally realized by externally connecting a pressure sensor, namely, a hole is formed in the battery cell and is connected with the pressure sensor through a related pipeline component, and the sealing is mainly realized by high-temperature glue, such as epoxy glue and the like. However, the sealing comparison depends on the performance of the glue and the glue coating mode, and as the test is carried out, when the epoxy glue and the sealing position are cracked and peeled, the test fails, so that the data is insufficient to build a prediction model, and the gas production risk cannot be estimated timely.

Disclosure of Invention

The utility model aims to provide an air pressure detection device which aims to prevent cracking between viscose and a sealing position and improve the success rate of testing so as to smoothly evaluate the risk of gas production of a battery.

The utility model aims to provide a pneumatic detection device which is applied to a battery to be detected, wherein the battery to be detected comprises a liquid injection port, and the pneumatic detection device comprises: the air duct is provided with a first end and a second end which are opposite, and the first end is used for being connected with the liquid injection port; the first sealant layer is covered on the outer peripheral side of the air duct; the sleeve is sleeved on the outer peripheral side of the air duct and is positioned outside the first sealing rubber layer; and the pressure detection piece is communicated with the second end and is used for detecting the internal pressure of the battery to be detected.

In one embodiment of the utility model, the air guide connector further comprises an air guide connector, wherein the air guide connector comprises a connecting section and a plugging section which are connected with each other, the connecting section is connected with the first end, and the plugging section is used for being connected with the liquid injection port;

the outer dimension of the connecting section increases toward the battery to be measured.

In one embodiment of the present utility model, the connection section is inserted into the first end, and the insertion depth of the connection section is at least half the length of the connection section itself.

In one embodiment of the present utility model, the first sealant layer is an epoxy layer.

In one embodiment of the present utility model, the air pressure detecting device further includes a second sealant layer, where the second sealant layer is connected to the connection section and the first end, and covers a connection portion between the connection section and the first end.

In an embodiment of the utility model, the second sealant layer is a photosensitive adhesive layer.

In one embodiment of the utility model, the insertion section is inserted into the liquid injection port, and the insertion section is welded with the liquid injection port.

In one embodiment of the utility model, the plug section has a radially extending overlap, which is located at the end of the plug section adjacent to the connection section,

the overlap joint portion has the overlap joint face, annotate the liquid mouth and have annotate the liquid terminal surface, the overlap joint face be used for with annotate the butt of liquid terminal surface.

In one embodiment of the utility model, the external dimensions of the plug section decrease in a direction away from the connection section.

The embodiment of the utility model also provides a single battery, which comprises the air pressure detection device.

According to the air pressure detection device and the single battery, when the air pressure detection device is connected with the single battery to be detected, the sleeve is sleeved outside the first sealing glue layer on the periphery of the air duct, so that the first sealing glue layer on the periphery of the air duct is restrained, the air duct is supported, the air leakage caused by stripping of the interface and the first sealing glue layer at the interface due to shaking of the air duct is prevented, the test success rate is improved, and the gas production risk of the battery is evaluated smoothly.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings required for the description of the embodiments will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to the drawings without inventive effort for a person skilled in the art. In addition, in the drawings, like parts are designated with like reference numerals and the drawings are not drawn to actual scale.

Fig. 1 is a schematic diagram of a simple structure of an air pressure detecting device according to an embodiment of the present utility model;

fig. 2 is a cross-sectional view illustrating the cooperation of an air duct, a first sealant layer and a sleeve in an air pressure detection device according to an embodiment of the present utility model;

FIG. 3 is a cross-sectional view of an air guide connector in an air pressure detecting device according to an embodiment of the present utility model;

FIG. 4 is a partial cross-sectional view showing an air duct and an air connector of an air pressure detecting device according to an embodiment of the present utility model;

FIG. 5 is a partial cross-sectional view showing the cooperation of another airway with an airway adapter in an air pressure detection device according to an embodiment of the present utility model;

FIG. 6 is a partial cross-sectional view showing the fitting of a further airway to an airway adapter in an air pressure detection device according to an embodiment of the present utility model;

FIG. 7 is a cross-sectional view of another air guide connector of an air pressure detecting device according to an embodiment of the present utility model;

fig. 8 is a schematic structural diagram of a sleeve in a pneumatic detection device according to an embodiment of the present utility model.

Reference numerals illustrate:

1. an air duct; 11. a first end; 12. a second end; 13. an air guide joint; 131. a connection section; 132. a plug section; 1321. a lap joint; 1321 a-faying surface; 2. a pressure detecting member; 3. a single battery; 31. a liquid injection port; 4. a sleeve; 41. a protrusion; 5. a first sealant layer; 6. and a second sealant layer.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Fig. 1 is a schematic diagram of a simple structure of an air pressure detecting device according to an embodiment of the present utility model during testing. Fig. 2 is a cross-sectional view illustrating the cooperation of the air duct, the first sealant layer and the sleeve in the air pressure detecting device according to the embodiment of the present utility model.

Referring to fig. 1 and 2, an embodiment of the present utility model provides an air pressure detecting device for a battery to be tested. The battery to be tested may be, for example, a unit battery 3 of a square aluminum case, or may be another type of unit battery 3, which is not particularly limited herein. The battery cell 3 has annotate liquid mouth 31, and air pressure detection device includes air duct 1, and air duct 1 has relative first end 11 and second end 12, and first end 11 is used for being connected with annotating liquid mouth 31, and first sealant layer 5 covers in the periphery side of air duct 1, and the periphery side of air duct 1 is located to sleeve pipe 4 cover, and sleeve pipe 4 is located outside first sealant layer 5, and pressure detection spare 2 and second end 12 intercommunication for detect the interior pressure of the battery cell 3 that is connected, for example, pressure detection spare 2 can be pressure sensor. In the service process of the single battery 3, when the gas production performance of the battery cell in the single battery 3 needs to be analyzed to confirm risks, the gas pressure detection device is connected with the single battery 3, so that the first end 11 is connected with the liquid injection port 31, when the gas pressure detection device is connected with the single battery 3, the first sealant layer 5 is coated on the outer periphery side of the gas guide tube 1 and extends to the connection position with the liquid injection port 31, and the sleeve 4 is sleeved on the outer periphery of the first sealant layer 5, so that the sleeve 4 can restrain the first sealant layer 5 and has a supporting function on the gas guide tube 1. Therefore, through the matching structure, when the first end 11 is in sealing connection with the liquid injection port 31, the sleeve 4 is utilized to prevent the interface caused by shaking of the air duct 1 and the first sealant layer 5 at the interface from being stripped to leak air, so that the test success rate is improved, and the gas production risk of the battery is evaluated smoothly.

Optionally, the air duct 1 is set to be a silicone tube, the single battery 3 is generally an aluminum shell, the top cover of the shell is directly provided with the liquid injection port 31, or a liquid injection pipe made of the same material and protruding from the top cover is arranged, the liquid injection pipe is provided with a liquid injection hole and communicated with the inside, the liquid injection port 31 is arranged on the liquid injection pipe, and the specific position, the size, the shape and the like of the liquid injection port 31 can be adaptively adjusted according to actual requirements, so that the method is not limited specifically. In the embodiment of the present utility model, the specific structure of the air pressure detecting device will be described in detail taking the example that the liquid inlet 31 is circular and is directly opened on the top cover.

In an alternative embodiment, the first end 11 of the air duct 1 is directly connected to the liquid injection port 31, and when the first end 11 is connected to the liquid injection port 31, the first end 11 is aligned to the liquid injection port 31, or a part of the air duct 1 extends into the liquid injection port 31, and then a sealant is coated on the periphery of the air duct 1 to form a first sealant layer 5, so that the first sealant layer 5 covers the metal part around the liquid injection port 31 at the same time, the first sealant layer 5 is used to fixedly connect the plastic air duct 1 with the top cover, and the connection part between the two is sealed, so that the first end 11 of the air duct 1 is communicated with the liquid injection port 31. On this basis, sleeve 4 is sleeved on the periphery of first sealing glue layer 5, and sleeve 4 is utilized to restrain first sealing glue layer 5 and support air duct 1 so as to reduce the risk of stripping first sealing glue layer 5.

Alternatively, for the sleeve 4 sleeved outside the first sealant layer 5, the sleeve may be sleeved only at a position of the air duct 1 close to the first end 11 or completely cover the air duct 1, and the end of the first end 11 is flush with the end of the sleeve 4; or, on the basis of being sleeved on the air duct 1, the sleeve 4 can also be extended to at least cover the joint of the air duct 1 and the liquid injection port 31, so that the stability of the sealing structure can be improved by utilizing the supporting function of the sleeve 4.

It will be appreciated that the sleeve 4 may be provided as a non-deformable metal or non-metal tube which is matched with the shape of the sleeved airway tube 1 and extends to the junction, and that the sleeve 4 is in clearance fit with the airway tube 1, and after the sleeve 4 is sleeved at the corresponding position, the clearance position between the sleeve 4 and the airway tube 1 and the junction is filled with sealant for fixing the sleeve 4. The shape, size, etc. of the sleeve 4 may be adaptively adjusted according to actual requirements, and are not particularly limited herein.

It is to be understood that the first sealant layer 5 is formed by applying the sealant in a liquid state on the outer periphery of the air duct 1, the outer periphery of the liquid injection port 31 and the connection therebetween, and then forming the first sealant layer 5 after curing, so that the shape of the first sealant layer 5 is obtained by final molding according to the application position thereof, and is not limited to a certain fixed shape, and will not be described in detail herein.

Optionally, the first sealant layer 5 is made of an ultraviolet adhesive that is rapidly solidified by ultraviolet irradiation, so as to be used for the fixed connection between the metal and the nonmetal between the air duct 1 and the top cover.

In an alternative embodiment, referring to fig. 3 to 7, the air pressure detecting device includes an air guide connector 13, and the air guide connector 13 is used to connect the first end 11 with the liquid injection port 31. The air guide connector 13 comprises a connecting section 131 and a plugging section 132 which are connected with each other, wherein the connecting section 131 is connected with the first end 11, and the plugging section 132 is used for being connected with the liquid injection port 31. In the embodiment, the air guide pipe 1 is connected with the liquid injection port 31 through the air guide connector 13, and the plug-in section 132 arranged by the air guide connector 13 is utilized to conveniently and rapidly realize the connection with the liquid injection port 31, so that the structure stability is better. In this structural fit, the first sealant layer 5 and the sleeved sleeve 4 covering the outer peripheral side of the air duct 1 may at least cover the connection position of the plugging section 132 and the liquid injection port 31 (as shown in fig. 4), so as to ensure a better sealing effect. Or on this basis, the first sealant layer 5 and the sleeved sleeve 4 may be expanded to cover the connection part between the connecting section 131 and the first end 11 (as shown in fig. 5), or even to cover the whole air duct 1, and may be adaptively adjusted according to actual requirements, which is not limited herein.

Optionally, the air guide connector 13 is provided as a metal piece, so as to facilitate connection of the air guide tube 1 and the liquid injection port 31.

Referring to fig. 7, for the connecting section 131, in order to achieve connection between the air guide connector 13 and the first end 11, structural stability after connection is improved, and the external dimension of the connecting section 131 is increased towards the direction of the single battery 3, so that in the process of inserting the connecting section 131 into the air guide tube 1, interference fit with the air guide tube 1 is achieved by using the increased dimension, and fixed connection of the two is achieved. Specifically, the air duct 1 and the air duct connector 13 are both in a circular tubular structure, the inner diameter of the air duct 1 is D, the outer diameter of one end of the connecting section 131 facing the first end 11 is D1, and D1 is the minimum outer diameter of the connecting section 131 along the length direction of the connecting section, where D1 is smaller than D, so as to extend into the inner diameter of the first end 11. The outer diameter of the connecting section 131 gradually increases along the direction towards the single battery 3, and the outer diameter of the other end of the connecting section 131 is D2, wherein D2 is more than D. The total length of the connecting segment 131 itself is L, from one end of the outer diameter D1 to the other end of the outer diameter D2, with increasing outer diameter, at the location where the length of the connecting segment 131 is L1 from the end of the outer diameter D1, the outer diameter D3, d3=d, or slightly greater than D to achieve an interference fit. When the air guide connector 13 is connected with the first end 11, one end of the connecting section 131 with the outer diameter D1 stretches into the inner diameter of the air guide tube 1 from the first end 11, and when the connecting section stretches into the length L1, the outer diameter D3 of the connecting section is the same as the inner diameter D of the air guide tube 1, so that the connecting section cannot stretch into the connecting section continuously, and the air guide connector 13 is fixedly connected with the air guide tube 1. Meanwhile, the gas guide joint 13 is plugged through the cooperation of the outer diameter of the gas guide joint 13 and the inner diameter of the gas guide pipe 1, so that when the gas moving along the inner diameter of the gas guide pipe 1 flows in the direction of the gas guide joint 13, the flowing direction of the gas is limited, and the gas can only flow from the inner diameter of the gas guide joint 13 to the liquid injection port 31.

Optionally, the external dimensions D1, D2, D3 of the connecting section 131 may be adaptively adjusted according to the inner diameter dimension D of the air duct 1, so as to meet the assembly and fixation requirements therebetween, which is not specifically limited herein. In the embodiment of the present utility model, in order to ensure the structural stability of the fixed connection manner of interference fit between the two, when the connection section 131 is inserted into the first end 11, the insertion depth of the connection section 131 is at least half the length of the connection section 131 itself, i.e., L1 > 1/2L.

In addition, a second sealant layer 6 may be further disposed at the connection between the connection section 131 and the air duct 1, where the second sealant layer 6 is connected to the connection section 131 and the first end 11, and covers the connection between the connection section 131 and the first end 11. It should be emphasized that the second sealant layer 6 is configured as a glue capable of bonding metal and nonmetal, such as an ultraviolet glue, etc., so as to ensure good sealing performance and structural stability of the connection therebetween, which is not particularly limited herein.

Alternatively, the first sealant layer 5 is an epoxy adhesive layer obtained by curing a metal-to-metal adhesive, such as an epoxy adhesive layer obtained by curing an epoxy adhesive, and the second sealant layer 6 is a photosensitive adhesive layer obtained by photo-curing a photosensitive adhesive. The first sealant layer 5 and the second sealant layer 6 are both applied in a liquid state at the corresponding positions by the sealant, and the cured form is not limited to a certain fixed form. The shape of the sleeve 4 sleeved on the outer side of the first sealant layer 5 can be adjusted according to the requirement, and the sleeve is not limited to a tubular structure with an equal diameter, but also can be a tubular structure with a variable diameter (as shown in fig. 5 and 6), and the sleeve is not particularly limited.

Optionally, the plugging section 132 is inserted into the liquid injection port 31, and the plugging section 132 can be welded to the liquid injection port 31 to improve structural stability of the fixed connection.

In another embodiment, the plugging section 132 may be configured to include a lap portion 1321 extending in the radial direction, where the lap portion 1321 is located at an end of the plugging section 132 near the connection section 131, the lap portion 1321 has a lap surface 1321a, the liquid injection port 31 has a liquid injection end surface, and the lap surface 1321a is used for abutting against the liquid injection end surface. It can be understood that, when the liquid injection port 31 is directly opened on the top cover, the liquid injection end surface is an outer surface portion of the top cover corresponding to the periphery of the liquid injection port 31, and the size of the overlap portion 1321 is larger than the size of the liquid injection port 31. That is, the overlap portion 1321 is a shoulder provided on the side of the insertion section 132 away from the pouring spout 31, and the outer diameter of the shoulder is D6, D6 is larger than the diameter of the pouring spout 31. And the maximum diameter D5 of the plugging section 132 is smaller than D6, so that when the plugging section 132 is connected with the liquid injection port 31, the plugging section 132 extends into the liquid injection port 31, and is limited by the dimension D6 of the lap joint portion 1321, and does not extend into the liquid injection port 31, and the lap joint surface 1321a of the lap joint portion 1321 facing the liquid injection port 31 can be abutted with the liquid injection end surface, so that the problem of welding and printing gaps is solved by the lap joint portion 1321.

Optionally, the outer dimensions of the plug section 132 decrease in a direction away from the connection section 131. That is, along the own length direction of the plugging section 132, one end of the plugging section 132 connected with the connection section 131 is provided with a lap joint 1321, and along the matching direction of the lap joint 1321 to the liquid injection port 31, the outer diameter of the position where the plugging section 132 is connected with the lap joint 1321 is D5, and gradually decreases, the outer diameter of the other end of the plugging section 132 is D4, D5 > D4, D5 is equal to the diameter of the liquid injection port 31 or slightly smaller than the diameter of the liquid injection port 31, and D4 is smaller than the diameter of the liquid injection port 31, so that the front end part can extend into the liquid injection port 31, and the position with the outer diameter dimension D5 is matched with the liquid injection port 31, and can realize welding at the matching position, thereby improving the stability and the sealing property of the connection between the two, and not described herein.

It should be emphasized that, no matter what kind of matching structure is adopted in the air pressure detection device and is in sealing connection with the single battery 3, in order to ensure better sealing performance, the first sealing glue layer 5 can select the adhesive with good sealing effect and difficult falling off according to the material adaptability of the object to be bonded, and the specific limitation is not made herein.

Referring to fig. 4 to 6, for the first sealant layer 5 and the sleeve 4, when the first end 21 is fixedly connected with the air guide connector 13 and connected with the liquid injection port 31 through the air guide connector 13, the first sealant layer 5 and the sleeve 4 sleeved outside may be only disposed at the position where the insertion end 132 is matched with the liquid injection port 31, as shown in fig. 4. Alternatively, the first sealant layer 5 and the sleeve 4 sleeved outside may extend in the direction of the connecting section 131 on the basis of this, so that at least the connecting position between the first end 21 and the air guide connector 13 (or the second sealant layer 6, see fig. 5 and 6) is covered. And or further extends upward to cover the entire outer peripheral side of the airway tube 1 to the second end 12, without being particularly limited herein.

Alternatively, referring to fig. 8, the inner wall of the sleeve 4 may be provided with a plurality of protrusions 41 or patterns or the like arranged at intervals to increase the contact area with the first sealant layer 5, so as to increase friction and thus support stability.

The embodiment of the utility model further provides a single battery 3, referring to fig. 1, including the air pressure detection device described in the foregoing, so as to be capable of detecting internal gas production in the service process of the single battery 3, so as to be capable of timely and accurately evaluating risks, which is not described herein.

It should be noted that, the air pressure detection device provided in the embodiment of the present utility model is not limited to be applied to the single battery 3, but may be applied to other structures that need to detect air, and will not be described again.

With specific reference to the figures, it should be noted that references in the specification to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It should be readily understood that the terms "on … …", "above … …" and "above … …" in this disclosure should be interpreted in the broadest sense such that "on … …" means not only "directly on something", but also includes "on something" with intermediate features or layers therebetween, and "above … …" or "above … …" includes not only the meaning "on something" or "above" but also the meaning "above something" or "above" without intermediate features or layers therebetween (i.e., directly on something).

Further, spatially relative terms, such as "below," "beneath," "above," "over," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may have other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.

Claims (10)

1. The utility model provides a pneumatic detection device, is applied to the battery that awaits measuring, the battery that awaits measuring includes annotates liquid mouth (31), its characterized in that, pneumatic detection device includes:

an air duct (1) having opposite first (11) and second (12) ends, said first (11) end being adapted to be connected to said filling port (31);

a first sealant layer (5) which covers the outer peripheral side of the air duct (1);

the sleeve (4) is sleeved on the outer peripheral side of the air duct (1), and the sleeve (4) is positioned outside the first sealant layer (5); and

and the pressure detection piece (2) is communicated with the second end (12) and is used for detecting the internal pressure of the battery to be detected.

2. The air pressure detection device according to claim 1, further comprising an air guide connector (13), the air guide connector (13) comprising a connecting section (131) and a plugging section (132) connected to each other, the connecting section (131) being connected to the first end (11), the plugging section (132) being adapted to be connected to the liquid filling port (31);

the outer dimension of the connecting section (131) increases toward the battery to be tested.

3. A barometric pressure sensing device according to claim 2, wherein said connection section (131) is inserted into said first end (11), said connection section (131) having an insertion depth of at least half the length of said connection section (131) itself.

4. The air pressure detection device according to claim 1, characterized in that the first sealant layer (5) is an epoxy glue layer.

5. The air pressure detection device according to claim 2, further comprising a second sealant layer (6), wherein the second sealant layer (6) is connected to the connection section (131) and the first end (11) respectively, and covers the connection of the connection section (131) and the first end (11).

6. The air pressure detection device according to claim 5, characterized in that the second sealing glue layer (6) is a photosensitive glue layer.

7. The air pressure detection device according to claim 2, wherein the insertion section (132) is inserted into the liquid injection port (31), and the insertion section (132) is welded to the liquid injection port (31).

8. The air pressure detecting device according to claim 7, wherein the insertion section (132) has a lap joint portion (1321) protruding in a radial direction, the lap joint portion (1321) being located at an end of the insertion section (132) near the connection section (131),

the overlap portion (1321) has an overlap surface (1321 a), the liquid injection port (31) has a liquid injection end surface, and the overlap surface (1321 a) is configured to abut against the liquid injection end surface.

9. The air pressure detecting device according to claim 7, wherein the outer dimension of the plug section (132) decreases in a direction away from the connection section (131).

10. A single cell comprising the air pressure detecting device according to any one of claims 1 to 9.