Secondary battery

Abstract

To provide a secondary battery that can easily grasp the magnitude of the internal pressure of a secondary battery.SOLUTION: A secondary battery 1 has a hemispherical component 22 that is provided in a pouring hole 21 and contracts when the internal pressure of the secondary battery 1 rises and a resin tape 23 that covers the hemispherical component 22 and seals the pouring hole 21. The hemispherical component 22 includes a pressure display portion 32 that is in contact with the resin tape 23 when the hemispherical component 22 contracts due to an increase in the internal pressure of the secondary battery 1. The amount of contact between the pressure display portion 32 and the resin tape 23 changes in accordance with the magnitude of the internal pressure of the secondary battery 1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to secondary batteries. [Background technology]

[0002] As a conventional technique relating to secondary batteries, Patent Document 1 discloses a battery (electrolyte battery) in which, when the internal pressure of the battery rises excessively, a thin plate is broken by a protrusion, releasing the internal pressure of the battery to the atmosphere. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 62-94561 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery disclosed in Patent Document 1, unless the protrusion breaks the thin plate and the internal pressure of the battery is released to the atmosphere, it is not possible to know that the internal pressure of the battery has increased excessively, and the magnitude of the internal pressure of the battery cannot be easily grasped.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and has an object to provide a secondary battery that allows the magnitude of the internal pressure of the secondary battery to be easily grasped. [Means for solving the problem]

[0006] One form of the present disclosure made to solve the above problems is characterized in that the case has an opening and a lid member that seals the opening, the lid member being provided in a through hole of a secondary battery having a through hole, the lid member having a contraction member that contracts due to an increase in internal pressure of the secondary battery, and a sealing member that covers the contraction member to seal the through hole, the contraction member having a contact portion that contacts the sealing member when the contraction member contracts due to an increase in internal pressure of the secondary battery, and the amount of contact between the contact portion and the sealing member changes depending on the magnitude of the internal pressure of the secondary battery.

[0007] According to this aspect, the magnitude of the internal pressure of the secondary battery can be grasped based on the amount of contact between the contact portion and the sealing member, and therefore the internal pressure of the secondary battery can be easily grasped.

[0008] In the above aspect, it is preferable that the contraction member is formed in a hemispherical or semi-capsule shape that is convex toward the inside of the case.

[0009] According to this aspect, the contraction member is formed in a hemispherical or semi-capsule shape, and is therefore susceptible to the internal pressure of the secondary battery acting from all directions. Furthermore, even if the internal pressure of the secondary battery acts on a localized position on the contraction member, it is likely to be dispersed and averaged over the entire surface of the contraction member. Therefore, the contraction member stably contracts according to the magnitude of the internal pressure of the secondary battery while maintaining its hemispherical or semi-capsule shape. Therefore, even if the internal pressure of the secondary battery is uneven, the internal pressure of the secondary battery can be accurately grasped.

[0010] In the above aspect, it is preferable that the contact portion is a stripe-like projection formed on the inner surface of the contraction member between the apex side and the bottom side of the hemispherical or semi-capsule shape.

[0011] According to this aspect, the internal pressure of the secondary battery can be accurately determined based on the length of the contact portion between the contact portion, which is a stripe-like projection, and the sealing member.

[0012] In the above aspect, it is preferable that a mark of contact with the contact portion remains on the sealing member.

[0013] According to this aspect, by checking the mark of contact with the contact portion of the sealing member, it is possible to grasp the history of changes in the internal pressure of the secondary battery.

[0014] In the above aspect, it is preferable that the contraction member has a penetrating protrusion portion which is a protrusion that penetrates the sealing member when the internal pressure of the secondary battery rises to or above a predetermined pressure and the contraction member contracts.

[0015] According to this aspect, when the internal pressure of the secondary battery rises above a predetermined pressure and becomes excessive, the internal pressure of the secondary battery can be released by penetrating the penetrating protrusion into the sealing member to create a hole in the sealing member. Therefore, it is not necessary to provide a separate mechanism such as a conventional release valve in the lid member, and the number of parts arranged in the lid member can be reduced, making the lid member smaller, and thus the secondary battery can be made smaller.

[0016] In the above aspect, it is preferable that the contraction member has a through hole for releasing the internal pressure of the secondary battery to the outside of the secondary battery when the penetrating protrusion portion penetrates the sealing member.

[0017] According to this aspect, when the internal pressure of the secondary battery becomes excessively high, the internal pressure of the secondary battery can be released through the through opening of the contraction member and the hole formed by passing the penetrating protrusion through the sealing member. Effect of the Invention

[0018] According to the secondary battery of the present disclosure, the magnitude of the internal pressure of the secondary battery can be easily grasped. [Brief description of the drawings]

[0019] [Figure 1] 1 is an overall perspective view of a secondary battery according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view of the resin tape, the hemispherical part, and the cover member (the liquid injection hole). [Diagram 3] FIG. 2 is a perspective view of the resin tape, the hemispherical part, and the cover member (the liquid injection hole). [Figure 4] 4 is a cross-sectional view (cross-sectional view taken along the line AA in FIG. 3) of the resin tape, the hemispherical part, and the cover member (the liquid injection hole) before the internal pressure of the secondary battery increases. [Diagram 5] 1 is a view of a hemispherical part seen from above through a resin tape before the internal pressure of the secondary battery increases. FIG. [Figure 6] 11 is a cross-sectional view of the resin tape, the hemispherical part, and the cover member (filling hole) when the internal pressure of the secondary battery increases. FIG. [Figure 7] 13 is a view of a hemispherical part seen from above through a resin tape when the internal pressure of the secondary battery increases. FIG. [Figure 8] 13 is a cross-sectional view of the resin tape, the hemispherical part, and the cover member (filling hole) when the internal pressure of the secondary battery is further increased. FIG. [Figure 9] 13 is a view of the hemispherical part as seen from above through the resin tape when the internal pressure of the secondary battery further increases. FIG. [Figure 10] 10 is a cross-sectional view of the resin tape, the hemispherical part, and the cover member (filling hole) when the internal pressure of the secondary battery rises to or exceeds a predetermined pressure. FIG. [Figure 11] 13 is a view of the hemispherical part as seen from above through the resin tape when the internal pressure of the secondary battery rises to or exceeds a predetermined pressure. FIG. [Figure 12] 10 is a cross-sectional view of the resin tape, the hemispherical part, and the cover member (liquid injection hole) when the internal pressure of the secondary battery is released. FIG. [Figure 13] FIG. 2 is a cross-sectional view showing an example of a semi-capsule shaped part. [Figure 14] FIG. 2 is a cross-sectional view showing an example of a semi-capsule shaped part. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the secondary battery of the present disclosure will be described.

[0021] 1, the secondary battery 1 of this embodiment has a case 11 with an opening 11a, and a lid member 12 that seals the opening 11a. The case 11 and the lid member 12 are made of metal (for example, aluminum).

[0022] The cover member 12 is provided with two electrode terminals 13. Of the two electrode terminals 13, one electrode terminal 13 is a positive terminal and the other electrode terminal 13 is a negative terminal. The two electrode terminals 13 are connected to an electrode body (not shown) housed in the case 11.

[0023] The lid member 12 also has a liquid injection hole 21 penetrating the lid member 12. The liquid injection hole 21 is a hole for injecting an electrolyte into the case 11. The liquid injection hole 21 is an example of a "through hole" in the present disclosure.

[0024] 1 to 4, in this embodiment, the secondary battery 1 has a hemispherical part 22 and a resin tape 23 at the position of the liquid injection hole 21 of the lid member 12. Note that the hemispherical part 22 is an example of the "shrinkable member" of the present disclosure, and the resin tape 23 is an example of the "sealing member" of the present disclosure.

[0025] The hemispherical part 22 is provided inside the liquid filling hole 21 of the lid member 12. This hemispherical part 22 is formed into a hemispherical shape that is convex toward the inside of the case 11. The hemispherical part 22 is made of metal (e.g., aluminum) or resin, and contracts due to an increase in the internal pressure of the secondary battery 1, as will be described in detail later.

[0026] 4 and 5, the hemispherical part 22 includes a hemispherical portion 31, a pressure indication portion 32, a sharp protrusion 33, and a flange portion 34. Note that the pressure indication portion 32 is an example of a "contact portion" in the present disclosure, and the sharp protrusion 33 is an example of a "piercing protrusion portion" in the present disclosure.

[0027] The hemispherical portion 31 is a portion formed in a hemispherical shape. The pressure display portion 32 is a protrusion (a blunt protrusion compared to the sharp protrusion 33) formed on the inner wall surface 31a of the hemispherical portion 31 so as to protrude from the inner wall surface 31a to the inside of the hemispherical portion 31. In detail, the pressure display portion 32 is a protrusion formed in a stripe shape extending from an apex portion 35 located at the apex side (lower side in FIG. 4) of the hemispherical shape of the hemispherical portion 31 to a connection portion 36 (a connection portion between the hemispherical portion 31 and the flange portion 34) located at the bottom side (upper side in FIG. 4) of the hemispherical shape of the hemispherical portion 31.

[0028] The sharp protrusion 33 is formed at the position of the apex 35 of the hemispherical portion 31 so as to protrude from the inner wall surface 31a of the hemispherical portion 31 toward the inside of the hemispherical portion 31. The sharp protrusion 33 is formed so as to protrude, for example, in a conical shape, and its tip is formed to be sharply pointed.

[0029] The flange portion 34 is connected to the hemispherical portion 31 at a connection portion 36, and is formed so as to extend outward from the hemispherical portion 31. The flange portion 34 is disposed on the upper surface 12a of the cover member 12, and the hemispherical part 22 is provided in the liquid injection hole 21 of the cover member 12. The flange portion 34 also includes a through hole 37 that passes through the flange portion 34.

[0030] Resin tape 23 is a sheet-like resin with an adhesive applied to one side (the side on which upper surface 12a of lid member 12 and hemispherical part 22 are placed) and covers hemispherical part 22 to seal injection hole 21. Resin tape 23 is transparent or semi-transparent, so that hemispherical part 22 can be seen through resin tape 23 from the upper surface 12a side of lid member 12.

[0031] Such a hemispherical part 22 and resin tape 23 are formed such that, after electrolyte is injected into the case 11 through the injection hole 21 of the lid member 12, the hemispherical part 22 is assembled into the injection hole 21 and the resin tape 23 is applied to cover the hemispherical part 22 from the upper surface 12a side of the lid member 12, thereby sealing the injection hole 21.

[0032] In the secondary battery 1 of this embodiment, the internal pressure of the secondary battery 1 can be easily grasped by using the hemispherical part 22 and the resin tape 23 provided at the position of the liquid filling hole 21 of the lid member 12 in this manner, as described below.

[0033] First, before the internal pressure of the secondary battery 1 increases (i.e., when the pressure is at a steady state), the hemispherical portion 31 of the hemispherical part 22 maintains its hemispherical shape and does not contract, as shown in Fig. 4. Furthermore, as shown in Figs. 4 and 5, the pressure indication portion 32 of the hemispherical part 22 is not in contact with the resin tape 23. That is, as shown in Fig. 5, the pressure indication portion 32 is not hatched with dots, which will be described later.

[0034] Next, when the internal pressure of the secondary battery 1 increases, the hemispherical portion 31 is pushed by the internal pressure of the secondary battery 1 and contracts, as shown in Fig. 6. At this time, since the hemispherical portion 31 is formed in a hemispherical shape, it is easily subjected to the internal pressure of the secondary battery 1 acting from all directions. Furthermore, even if the internal pressure of the secondary battery 1 acts at a localized position on the hemispherical portion 31, it is likely to be dispersed and averaged over the entire surface of the hemispherical portion 31. Therefore, the hemispherical portion 31 contracts stably in accordance with the magnitude of the internal pressure of the secondary battery 1 while maintaining its hemispherical shape.

[0035] When the hemispherical portion 31 contracts in this manner due to an increase in the internal pressure of the secondary battery 1, the pressure display portion 32 comes into contact with the resin tape 23, as shown in Fig. 6. When the hemispherical part 22 is viewed from the upper surface 12a side of the lid member 12 through the resin tape 23, the portion where the pressure display portion 32 comes into contact with the resin tape 23 (i.e., the portion indicated by dotted hatching) can be confirmed, as shown in Fig. 7.

[0036] Here, the portion where the pressure display part 32 contacts the resin tape 23 can be confirmed because, for example, a difference in shade or color appears between the portion where the pressure display part 32 is not in contact with the resin tape 23. Alternatively, the portion where the pressure display part 32 contacts the resin tape 23 can be confirmed because it appears to be raised more than the portion where the pressure display part 32 is not in contact with the resin tape 23. Note that markings such as scales may be provided on the pressure display part 32 or the resin tape 23 so that the amount of contact between the pressure display part 32 and the resin tape 23 can be easily understood.

[0037] Furthermore, in this embodiment, the resin tape 23 is designed to leave a mark when it comes into contact with the pressure display unit 32. For example, the portion of the resin tape 23 that comes into contact with the pressure display unit 32 is designed to have a different color or gloss compared to the portion not in contact with the pressure display unit 32, by peeling off an adhesive or dye previously applied to the resin tape 23, or by causing a dye previously applied to the pressure display unit 32 to adhere to the resin tape 23, so that a mark is left.

[0038] Then, thereafter, the amount of contact between the pressure display part 32 and the resin tape 23 changes in accordance with the amount of contraction of the hemispherical portion 31 depending on the magnitude of the internal pressure of the secondary battery 1. That is, as shown in Fig. 8, when the internal pressure of the secondary battery 1 further increases, the hemispherical portion 31 is pushed by the internal pressure of the secondary battery 1 and further contracts. Then, as shown in Figs. 8 and 9, the amount of contact between the pressure display part 32 and the resin tape 23 (i.e., the size (length) of the contact area (area shown by dotted hatching in Fig. 9)) further increases.

[0039] Then, when the internal pressure of the secondary battery 1 subsequently rises above a predetermined pressure (pressure required to release the internal pressure of the secondary battery 1), the hemispherical portion 31 is pressed by the internal pressure of the secondary battery 1 and further contracts, further increasing the amount of contact between the pressure indication portion 32 and the resin tape 23, as shown in Figures 10 and 11. Then, the sharp protrusions 33 then further tear and widen the holes formed in the resin tape 23.

[0040] In this way, when the internal pressure of the secondary battery 1 rises above a predetermined pressure and becomes excessive, the sharp projections 33 penetrate the resin tape 23 to make holes in the resin tape 23 and tear and open the resin tape 23, thereby releasing the internal pressure of the secondary battery 1 as shown in Fig. 12. In more detail, the internal pressure of the secondary battery 1 is released to the outside of the secondary battery 1 through the torn portion of the hemispherical portion 31 and the torn portion of the resin tape 23, and / or through the through hole 37 of the hemispherical part 22 and the torn portion of the resin tape 23.

[0041] In this way, the secondary battery 1 of this embodiment has the following functions combined: sealing the liquid injection hole 21 with the resin tape 23 at the position of the liquid injection hole 21 in the cover member 12; displaying the internal pressure of the secondary battery 1 by the amount of contact between the pressure indicator 32 and the resin tape 23 in response to an increase in the internal pressure of the secondary battery 1; and releasing the internal pressure of the secondary battery 1 by penetrating the resin tape 23 with the sharp protrusion 33 when the internal pressure of the secondary battery 1 becomes excessive.

[0042] As described above, the secondary battery 1 of this embodiment has the hemispherical part 22 and the resin tape 23 at the position of the electrolyte injection hole 21 of the lid member 12. The hemispherical part 22 has the pressure indicator 32 that comes into contact with the resin tape 23 when the hemispherical portion 31 of the hemispherical part 22 contracts due to an increase in the internal pressure of the secondary battery 1. The amount of contact between the pressure indicator 32 and the resin tape 23 changes depending on the magnitude of the internal pressure of the secondary battery 1.

[0043] This makes it possible to grasp the magnitude of the internal pressure of the secondary battery 1 based on the amount of contact between the pressure indicator 32 and the resin tape 23. Here, the amount of contact between the pressure indicator 32 and the resin tape 23 can be confirmed by looking at the hemispherical part 22 through the resin tape 23 from the upper surface 12a side of the lid member 12. Therefore, the internal pressure of the secondary battery 1 can be easily grasped.

[0044] Therefore, for example, when reusing a collected secondary battery 1, it is possible to identify secondary batteries 1 that may have an internal short circuit, a decrease in battery capacity, etc. by checking the amount of contact between the pressure indicator 32 and the resin tape 23 and grasping the internal pressure of the secondary battery 1. Also, when the secondary battery 1 is in use, the internal pressure of the secondary battery 1 can be easily confirmed by checking the amount of contact between the pressure indicator 32 and the resin tape 23.

[0045] Moreover, the hemispherical part 22 is formed in a hemispherical shape that is convex toward the inside of the case 11.

[0046] In this way, because hemispherical part 22 is formed in a hemispherical shape, it is easily subjected to the internal pressure of secondary battery 1 acting from all directions. Furthermore, even if the internal pressure of secondary battery 1 acts at a localized position on hemispherical part 22, it is likely to be dispersed and averaged over the entire surface of hemispherical part 22 which is formed in a hemispherical shape. Therefore, hemispherical part 22 stably contracts according to the magnitude of the internal pressure of secondary battery 1 while maintaining its hemispherical shape. Therefore, even if there are unevenness in the internal pressure of secondary battery 1, the internal pressure of secondary battery 1 can be accurately grasped.

[0047] The pressure display portion 32 is a stripe-like protrusion formed on the inner wall surface 31a of the semispherical portion 31 between the apex side and the bottom side of the semispherical shape.

[0048] This makes it possible to accurately grasp the internal pressure of the secondary battery 1 based on the length of the contact portion between the pressure indicating portion 32, which is a stripe-like protrusion, and the resin tape 23.

[0049] Furthermore, the resin tape 23 is designed to leave a mark where it comes into contact with the pressure indicator 32. Therefore, by checking the mark on the resin tape 23 where it comes into contact with the pressure indicator 32, it is possible to grasp the history of changes in the internal pressure of the secondary battery 1. Therefore, for example, it is possible to grasp the magnitude of the maximum internal pressure of the secondary battery 1.

[0050] Moreover, the hemispherical part 22 has a sharp protrusion 33 which penetrates the resin tape 23 when the internal pressure of the secondary battery 1 rises above a predetermined pressure and the hemispherical part 31 of the hemispherical part 22 contracts.

[0051] As a result, when the internal pressure of the secondary battery 1 rises above a predetermined pressure and becomes excessive, the sharp projection 33 penetrates the resin tape 23 to make a hole in the resin tape 23, thereby allowing the internal pressure of the secondary battery 1 to be released. In this way, the secondary battery 1 has a function of sealing the liquid injection hole 21 at the position of the liquid injection hole 21 of the lid member 12, a function of grasping the internal pressure of the secondary battery 1, and a function of releasing the internal pressure of the secondary battery 1. Therefore, it is not necessary to provide a separate mechanism such as a conventional release valve in the lid member 12, and the number of parts arranged in the lid member 12 can be reduced to reduce the size of the lid member 12, thereby allowing the secondary battery 1 to be reduced in size. In addition, since the parts arranged in the lid member 12 can be concentrated at the position of the liquid injection hole 21, a writing surface for writing information about the secondary battery 1 can be secured in the lid member 12.

[0052] Furthermore, the hemispherical part 22 has a through hole 37 in its flange 34 for releasing the internal pressure of the secondary battery 1 to the outside of the case 11 when the sharp projection 33 penetrates the resin tape 23 .

[0053] As a result, when the internal pressure of the secondary battery 1 becomes excessively high, the internal pressure of the secondary battery 1 can be released through the through hole 37 of the hemispherical part 22 and the hole created by penetrating the sharp protrusion 33 in the resin tape 23.

[0054] As a modified example, instead of the hemispherical part 22, a semi-capsule-shaped part 24 formed in a semi-capsule shape that protrudes toward the inside of the case 11 may be used, as shown in FIG. 13 or FIG.

[0055] Furthermore, by arranging a magnetic body on the pressure display unit 32, the amount of contact between the pressure display unit 32 and the resin tape 23 can be detected as an electrical signal, for example, by an electromagnetic sensor (not shown) provided on the resin tape 23. In this case, the resin tape 23 does not necessarily have to be transparent or semi-transparent, and the hemispherical part 22 does not necessarily have to be visible through the resin tape 23 from the upper surface 12a side of the lid member 12.

[0056] Moreover, by changing the height, width, and number of the pressure display sections 32, the internal pressure of the secondary battery 1 can be grasped from minute pressure to large pressure.

[0057] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0058] 1 Secondary battery 11 Cases 11a opening 12 Lid member 12a Top side 13 Electrode terminal 21 Filling hole 22 Hemispherical parts 23 Resin Tape 24 Semi-capsule shaped parts 31 Hemispherical part 31a Inside 32 Pressure display unit 33 Sharp protrusions 34 Flange section 35 Apex 36 Connection 37 Through Hole

Claims

1. a case having an opening; a cover member that seals the opening, In the secondary battery, the cover member is provided with a through hole, a contraction member provided in the through hole and contracting due to an increase in internal pressure of the secondary battery; a sealing member that covers the shrinkable member and seals the through hole, the contraction member includes a contact portion that comes into contact with the sealing member when the contraction member contracts due to an increase in internal pressure of the secondary battery, a contact amount between the contact portion and the sealing member changes depending on an internal pressure of the secondary battery; A secondary battery characterized by:

2. 2. The secondary battery of claim 1, the contraction member is formed in a hemispherical or semi-capsule shape that is convex toward the inside of the case; A secondary battery characterized by:

3. 3. The secondary battery of claim 2, the contact portion is a stripe-like protrusion formed on the inner surface of the contraction member between the apex side and the bottom side of the hemispherical or semicapsule shape; A secondary battery characterized by:

4. 4. The secondary battery according to claim 1, a mark of contact with the contact portion remains on the sealing member; A secondary battery characterized by:

5. 5. The secondary battery according to claim 1 , the contraction member has a penetrating protrusion portion which is a protrusion that penetrates the sealing member when the internal pressure of the secondary battery increases to or exceeds a predetermined pressure and the contraction member contracts; A secondary battery characterized by:

6. 6. The secondary battery of claim 5, the contraction member has a through hole for releasing the internal pressure of the secondary battery to the outside of the secondary battery when the through-projection portion penetrates the sealing member; A secondary battery characterized by:

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