JP6994156B2 - Sealed battery - Google Patents

Description

The present invention relates to a sealed battery. More specifically, the present invention relates to a sealed battery including a case provided with electrode terminals and an electrode body housed in the case.

Secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries are becoming more important as power sources for vehicles or as power sources for personal computers and mobile terminals. Such a secondary battery is constructed as, for example, a so-called closed-type battery in which an electrolytic solution and an electrode body are housed in a closed case. The sealed battery is provided with an electrode terminal connected to an external device such as a vehicle motor or another battery.

FIG. 6 shows an example of the structure near the electrode terminal of the sealed battery. As shown in FIG. 6, the electrode terminal 120 of the sealed battery 100 is attached to the case 110, and includes an external connection member 140 and a current collector member 150. The current collector member 150 is a long conductive member extending in the height direction Z, and its lower end is connected to an electrode body (not shown) inside the case 110. On the other hand, the upper end portion 150a of the current collector member 150 penetrates the case 110 and is exposed to the outside. Further, the external connecting member 140 is a plate-shaped conductive member extending along the width direction X of the sealed battery 100, and the upper end portion 150a of the current collecting member 150 is attached to one end of the external connecting member 140. Is inserted. Further, the other end of the external connecting member 140 is joined to the bus bar 130, and is electrically connected to an external device (such as a vehicle motor or another battery) via the bus bar 130.

A disk-shaped cap portion 152 is formed on the upper end portion 150a of the current collecting member 150 of the sealed battery 100. The cap portion 152 is formed by pressing and deforming the upper end portion of the current collecting member 150 by caulking. By forming the disc-shaped cap portion 152 by such caulking, the external connecting member 140 is fixed to the case 110, and the current collecting member 150 and the external connecting member 140 are adhered to form a conduction path. To. Further, due to the pressure of this caulking process, the insulating holder 162 and the internal sealing material 164 are held in the case 110, and the inside of the case 110 is sealed.
Patent Document 1 describes an example of a technique of pressing and deforming the upper end portion of a current collector member by caulking.

Japanese Unexamined Patent Publication No. 2016-105355

However, in the sealed battery 100 having the above-mentioned structure, various problems may occur in the vicinity of the electrode terminal 120, and it has been desired to solve these problems.
For example, when a shock or vibration is applied while the sealed battery 100 is connected to an external device via a bus bar 130 and the external connection member 140 moves up and down as shown in FIG. 7, the current collector member There is a risk that the cap portion 152 of the 150 will be significantly plastically deformed. In such a case, the pressure for holding the internal sealing material 164 may decrease, and the sealing property inside the case 110 may decrease.

The present invention has been made in view of this point, and the main object thereof is to appropriately suppress the plastic deformation of the current collector member when the external connecting member moves up and down, and to maintain the sealing property. The purpose is to provide a mold battery.

In order to realize the above object, the present invention provides a sealed battery having the following configuration.

In the sealed battery disclosed here, the case accommodating the electrode body and the lower end portion are electrically connected to the electrode body inside the case, and the upper end portion penetrates the case and is exposed to the outside of the case. A long current collector and a plate-shaped conductive member provided on the outside of the case. The upper end of the current collector is inserted through one end, and an external device is connected to the other end. It includes an external connecting member, an insulating holder arranged between the case and the external connecting member, and an internal sealing material arranged between the case and the current collecting member. In such a sealed battery, a disk-shaped cap is formed at the upper end of the current collecting member, and the external connecting member, the insulating holder, and the internal sealing material are fixed to the case by the disk-shaped cap. ing.
The sealed battery disclosed here is configured so that the proof stress of the external connection member is smaller than the proof stress of the cap portion of the current collector member.

In a general sealed battery, the current collector member is made of a relatively soft material in order to perform caulking properly, and the current collector member is more likely to undergo plastic deformation than the external connection member. On the other hand, the sealed battery disclosed here is configured so that the proof stress of the external connection member is smaller than the proof stress of the cap portion of the current collector member. In this way, when an external connecting member having a low yield strength and being relatively easily deformed is used, when the external connecting member moves up and down due to vibration or the like, the cap portion of the current collecting member is sunk into the external connecting member. The connecting member is deformed. Therefore, according to the sealed battery disclosed here, even when the external connecting member moves up and down, the plastic deformation of the current collecting member can be suitably suppressed, so that the internal sealing material is held. The pressure for this can be suitably maintained, and the airtightness of the case can be suitably maintained.

It is a perspective view which shows typically the closed type battery which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the structure near the electrode terminal of the closed type battery shown in FIG. 1. It is sectional drawing of the structure near the electrode terminal explaining the state which the external connection terminal moved up and down in the closed type battery which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the structure near the electrode terminal of the closed type battery which concerns on other embodiment of this invention. It is sectional drawing which shows typically the structure near the electrode terminal of the closed type battery which concerns on other embodiment of this invention. It is sectional drawing which shows typically the structure near the electrode terminal of the conventional closed type battery. It is sectional drawing of the structure near the electrode terminal explaining the state which the external connection terminal moved up and down in the conventional closed type battery.

Hereinafter, a lithium ion secondary battery will be described as an example of the sealed battery according to the embodiment of the present invention. The sealed battery disclosed here is not particularly limited as long as the electrode body is housed in the case. Therefore, the sealed battery disclosed here can be applied to a nickel hydrogen battery or the like in addition to the lithium ion secondary battery.

Further, in the following drawings, members / parts having the same action are described with the same reference numerals. The dimensional relationships (length, width, thickness, etc.) in each figure do not reflect the actual dimensional relationships. In addition, matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention (for example, general matters relating to the construction of a lithium ion secondary battery such as the composition and manufacturing method of an electrode body and an electrolytic solution). Technology, etc.) can be grasped as a design item of a person skilled in the art based on the prior art in the field.

1. 1. Structure of Sealed Battery (1) Overall Structure FIG. 1 is a perspective view schematically showing a sealed battery according to the present embodiment. In FIG. 1, reference numeral X indicates a width direction of the closed-type battery, reference numeral Y indicates a thickness direction, and reference numeral Z indicates a height direction.

As shown in FIG. 1, the sealed battery 1 according to the present embodiment includes a flat square case 10. The case 10 of the sealed battery 1 is composed of a square case body 12 having an open upper surface and a plate-shaped lid 14 that closes the opening on the upper surface of the case body 12. It is preferable that the case 10 is mainly made of a lightweight metal material having good thermal conductivity such as aluminum.

The electrode body 70 and an electrolytic solution (not shown) are housed inside the case 10. The electrode body 70 shown in FIG. 1 is a wound electrode body in which a sheet-shaped positive electrode and a negative electrode are wound via a separator, but the structure of the electrode body is not particularly limited. As for the material of the electrode body and the electrolytic solution, the same materials as those of the conventional general lithium ion secondary battery can be used without particular limitation, and therefore detailed description thereof will be omitted.

In this sealed battery 1, the electrode terminal 20 is provided on the lid 14 on the upper surface of the case 10, and the electrode terminal 20 is a connecting member for connecting to an external device such as a vehicle motor or another battery. (Bus bar) is connected. Hereinafter, the specific structure of the electrode terminal 20 will be described.

(2) Structure of Electrode Terminal FIG. 2 is a cross-sectional view schematically showing a structure in the vicinity of the electrode terminal 20 of the sealed battery 1 shown in FIG. As shown in FIG. 2, the electrode terminal 20 of the sealed battery 1 according to the present embodiment includes a current collector member 50, an external connection member 40, and an insulating member 60. Reference numeral 30 in FIG. 2 indicates the above-mentioned bus bar. Hereinafter, each member will be described.

(A) Current collector member As shown in FIG. 1, the current collector member 50 is a long conductive member extending along the height direction Z of the sealed battery 1, and the lower end portion 51 is an electrode in the case 10. It is electrically connected to the body 70. On the other hand, as shown in FIG. 2, the upper end portion 50a of the current collecting member 50 penetrates the lid 14 of the case 10 and the external connecting member 40 and the insulating member 60 described later and is exposed to the outside of the case 10. There is.
A disk-shaped cap portion 52 is formed at the upper end portion 50a of the current collecting member 50, and the disc-shaped cap portion 52 allows the external connecting member 40 and the insulating member 60 to form a lid 14 ( It is fixed to the case 10). The disk-shaped cap portion 52 is formed by pressing and deforming the upper end portion 50a of the current collecting member 50 by caulking.

(B) External Connection Member The external connection member 40 is a flat plate-shaped conductive member arranged outside the case 10 and extends along the width direction X of the sealed battery 1. In the sealed battery 1 according to the present embodiment, the upper end portion 50a of the current collecting member 50 is inserted through one end portion 42 of the external connection member 40, and the bus bar 30 is joined to the upper surface of the other end portion 44. As a result, the electrode body 70 (see FIG. 1) and the bus bar 30 are connected via the external connection member 40 and the current collector 50, and the external device such as another battery or motor and the sealed battery 1 are electrically connected. Connected to. The means for joining the external connecting member 40 and the bus bar 30 is not particularly limited, and laser welding, friction joining, or the like can be used.

(C) Insulation member In the sealed battery 1 according to the present embodiment, the insulation holder 62 is used to prevent continuity between the constituent members of the electrode terminal 20 and the case 10 and to maintain the airtightness (sealing property) inside the case 10. An insulating member 60 composed of an internal sealing material 64 and an internal sealing material 64 is attached to the lid body 14. The insulating holder 62 is arranged between the upper surface (outer surface) of the lid 14 and the external connecting member 40, and prevents the external connecting member 40 from coming into contact with the lid 14 and conducting conduction. On the other hand, the internal sealing material 64 is arranged inside the case 10 and is arranged between the lid 14 and the current collecting member 50. For each member constituting the insulating member 60, for example, a polyamide resin, a polyacetal resin, a polyimide resin, or the like is preferably used.
Further, an annular protrusion 64a is formed on the internal sealing material 64. The protrusion 64a of the internal sealing material 64 is inserted into a hole formed in the lid 14 and the insulating holder 62. The inside of the case 10 is appropriately sealed by pressing the annular protrusion 64a of the internal sealing material 64 from the cap portion 52 of the current collecting member 50 with a predetermined pressure.

(3) Proof stress of the current collector member and the external connection terminal The sealed battery 1 according to the present embodiment is configured such that the proof stress of the external connection member 40 is smaller than the proof stress of the cap portion 52 of the current collector member 50. ing. In other words, in the present embodiment, the external connecting member 40 is configured to be more easily plastically deformed than the current collecting member 50. As a result, the plastic deformation of the current collecting member 50 when the external connecting member 40 moves up and down can be suitably suppressed, and the hermeticity (sealing property) of the case 10 can be suitably maintained. Hereinafter, a specific description will be given.

In a general sealed battery 100 as shown in FIG. 6, a relatively soft (low resistance) metal material (for example, 1000 series aluminum) is used for easy caulking to form the cap portion 152. Etc.) are used in the current collector member 150. Therefore, as shown in FIG. 7, when the external connecting member 140 moves up and down and stress is applied to the cap portion 152 of the current collecting member 150, the cap portion 152 is greatly plastically deformed and the seal inside the case 110 is sealed. There is a risk of reduced sex.
In order to suppress such plastic deformation of the cap portion 152, in the conventional technique, a metal material having a high yield strength is used for the external connecting member 140, or an external connecting member bent into a Z-shaped cross section is used. As a result, the vertical movement of the external connecting member 140 itself was suppressed. However, with such a technique, when an unexpectedly large external force is applied and the external connecting member 140 moves up and down, plastic deformation of the cap portion 152 is unavoidable, so that the sealing property inside the case 110 may still deteriorate. It was left.

On the other hand, the sealed battery 1 according to the present embodiment shown in FIG. 2 can suppress the plastic deformation of the cap portion 52 of the current collecting member 50 even if the external connecting member 40 moves up and down. It is built on. Specifically, the sealed battery 1 according to the present embodiment is configured so that the proof stress of the part connecting member 40 is smaller than the proof stress of the cap portion 52 of the current collecting member 50. The case where a large external force is applied to the external connection member 40 of the sealed battery 1 will be described below.

FIG. 3 is a cross-sectional view of a structure in the vicinity of the electrode terminals for explaining a state in which the external connection terminal moves up and down in the sealed battery according to the present embodiment. As shown in FIG. 3, when a large external force is applied to the external connecting member 40 via the bus bar 30, the external connecting member 40 moves up and down. At this time, in the present embodiment, since the proof stress of the external connecting member 40 is configured to be smaller than the proof stress of the current collecting member 50, the external connecting member 40 is more easily deformed than the current collecting member 50. .. Therefore, even if the external connecting member 40 moves up and down significantly, the cap portion 52 only sinks into the external connecting member 40, and the cap portion 52 itself does not undergo large plastic deformation. Therefore, the pressure for holding the internal sealing material 64 is applied. It can be suitably maintained.
As described above, according to the sealed battery 1 according to the present embodiment, the internal sealing material 64 is suitable because the plastic deformation of the current collecting member 50 when the external connecting member 40 moves up and down can be suitably suppressed. It is possible to maintain the airtightness (sealing property) of the case 10 by holding it in the case.

The method of reducing the proof stress of the external connecting member 40 to be smaller than the proof stress of the cap portion 52 of the current collecting member 50 is not particularly limited, and various means can be adopted.
As an example of such means, a means of using a material having a lower rigidity than the current collecting member 50 for the external connecting member 40 can be mentioned. As a result, the external connection member 40 can be more easily deformed than the current collector member 50, so that the plastic deformation of the cap portion 52 (current collector member 50) can be more preferably suppressed.

Further, in the above aspect, the materials of the external connecting member 40 and the current collecting member 50 are different from each other, but the materials of the external connecting member 40 and the current collecting member 50 may be the same. For example, when the external connecting member 40 and the current collecting member 50 are made of the same material, means such as forming a notch in the external connecting member 40 or reducing the thickness of the external connecting member 40. By adopting the above, the strength of the external connecting member 40 can be lowered, and the external connecting member 40 can be easily deformed. However, in consideration of preventing the strength of the external connecting member 40 from being lowered due to stress concentration, it is preferable to make the external connecting member 40 and the metal material constituting the current collecting member 50 different from each other as described above.

2. 2. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and includes various modifications and modifications of the sealed battery according to the above-mentioned embodiment. Is done.

For example, in the above-described embodiment, a flat plate-shaped external connecting member 40 is used. However, the shape of the external connecting member is not limited to the above-described embodiment. Specifically, as shown in FIG. 4, an external connecting member 40A bent in a Z-shaped cross section can also be used. By using the external connecting member 40A bent in such a Z-shaped cross section, the vertical movement of the external connecting member 40 when an external force is applied can be suppressed, so that the cap portion 52 of the current collecting member 50 is more preferably used. Plastic deformation can be suppressed.

Further, in the above-described embodiment, the external connecting member 40 and the bus bar 30 are electrically connected by joining the bus bar 30 to the external connecting member 40.
However, the structure for connecting the external connecting member 40 and the bus bar 30 is not limited to this, and for example, a structure using bolts 80 and nuts 82 as shown in FIG. 5 can be adopted. In the sealed battery 1 having the structure shown in FIG. 5, a bolt insertion hole 44a is formed at the other end 44 of the external connection member 40, and a columnar bolt 80 through which the bolt insertion hole 44a is inserted is outside the case 10. It is provided on the insulating holder 62 of. In the sealed battery 1 having such a structure, the external connecting member 40 and the bus bar 30 can be connected by inserting the bolt 80 into the bus bar 30 having a through hole and tightening the nut 82 to the bolt 80. Even in the case of the sealed battery 1 having such a bolt 80, when the external connecting member 40 moves up and down by making the yield strength of the external connecting member 40 smaller than the yield strength of the current collecting member 50. It is possible to suppress the plastic deformation of the current collecting member 50 and maintain the hermeticity (sealing property) of the case 10.
Since the bus bar 30 can be replaced in the sealed battery 1 having such a bolt 80 as needed, the versatility can be improved as compared with the sealed battery 1 shown in FIG. 2 described above. ..

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

1,100 Sealed battery 10,110 Case 12 Case body 14 Lid 20, 120 Electrode terminal 30, 130 Bus bar 40, 40A, 140 External connection member 42 (of external connection member) One end 44 (of external connection member) ) Other end 44a Bolt insertion hole 50, 150 Current collecting member 50a, 150a Upper end of current collecting member 51 Lower end of current collecting member 52, 152 Cap 60, 160 Insulating member 62, 162 Insulating holder 64, 164 Inside Sealing material 64a Circular protrusion 70 Electrode body 80 Bolt 82 Nut X (sealed battery) Width direction Y (sealed battery) thickness direction Z (sealed battery) height direction

Claims (1)

A case that houses the electrode body and
A long current collector member whose lower end is electrically connected to the electrode body in the case and whose upper end penetrates the case and is exposed to the outside of the case.
An external connecting member which is a plate-shaped conductive member provided on the outside of the case, in which the upper end portion of the current collecting member is inserted through one end portion and an external device is connected to the other end portion.
An insulating holder arranged between the case and the external connecting member,
An internal sealing material arranged between the case and the current collector member is provided.
A disk-shaped cap is formed at the upper end of the current collecting member, and the external connecting member, the insulating holder, and the internal sealing material are fixed to the case by the disk-shaped cap. It ’s a sealed battery,
A sealed battery in which the rigidity of the metal material constituting the external connection member is lower than the rigidity of the metal material constituting the current collector member, and the proof stress of the external connection member is smaller than the proof stress of the cap portion of the current collector member. ..

Images