JP4590911B2 - battery - Google Patents

Description

  The present invention relates to a battery such as a lithium secondary battery. More specifically, the present invention relates to a battery having electrode terminals protruding outside the case.

  In recent years, secondary batteries such as lithium batteries have become widespread. Such a battery is required to have good properties at each of the following points with respect to the terminal mounted protruding from the case. That is, the terminal prevents the terminal from coming off from the battery, the insulation between the terminal and the case member, the sealability for preventing the internal electrolyte from leaking from the terminal part, and the like. Particularly in the case of a secondary battery, there is a change in internal pressure due to charging / discharging in the case, and in particular, the internal pressure may increase greatly during an abnormality such as an internal short circuit. Furthermore, in a battery can structure secondary battery in which a power generation element is enclosed in a can case, the strength of the can case itself is high, so internal pressure tends to be applied to the connection part of the terminal, and the structure of the terminal part is important. Become.

  Conventionally, as such a terminal structure in such a battery, for example, a through hole for a terminal is formed in a metal lid portion attached to a can case, and a columnar terminal is attached through the through hole. is there. In general, a cylindrical fixing portion is extended around the through-hole, and an insulating resin is sandwiched between them to fix it together with the terminals. There was a structure that tried to secure the insulation and sealing properties as well as the retaining properties by pressing the resin into the crimped parts.

Furthermore, in such a secondary battery, the internal pressure increases greatly especially when an abnormality such as an internal short circuit occurs. For this reason, various devices have been devised so far that the terminal fixed to the lid portion does not come out even when the internal pressure rises (see, for example, Patent Document 1). In the battery described in this document, an insulating resin is provided between the lid portion and the terminal. A flange portion is provided on the lid portion and the terminal, and is fitted into the groove of the insulating resin to prevent the insulating resin from coming off.
JP 2003-208879 A

  However, in the structure of the terminal portion in each of the conventional batteries described above, the resin inserted between the lid portion and the terminal may be deformed by the internal pressure due to insulation. In particular, when the resin is deformed by a large internal pressure generated in an abnormal state, there is a possibility that a slight gap may be formed between the lid portion and the terminal that are not deformed. When gas generated inside enters the gap, there is a problem that the sealing performance deteriorates and the internal gas may leak out. Furthermore, secondary batteries provided in automobiles and the like have a problem that the terminals may be loosened or pulled out because forces in various directions are applied by external vibration.

  The present invention has been made to solve the problems of the conventional batteries described above. That is, an object of the present invention is to provide a battery having a structure of a terminal portion that can ensure a good retaining property, insulating property and sealing property even when the internal pressure is greatly increased.

The battery of the present invention made for the purpose of solving this problem is a battery in which a power generation element is housed in a case and an electrode terminal connected to the power generation element protrudes outside through the case. A cylindrical holding part that penetrates the electrode terminal is provided outward in part, and a first taper part having a large diameter at the base end side is provided at the base part, and the holding part penetrates the electrode terminal. And a second tapered portion having a small diameter on the outer peripheral surface of the main body portion and having a small diameter on the power generation element side, and a cylindrical insulating material between the holding portion and the electrode terminal The insulating material faces the first taper portion and has a third taper portion on the outer surface having a large diameter on the proximal end side and a first taper portion on the inner surface facing the second taper portion and having a small diameter on the power generation element side . 4 taper parts are provided for insulation and insulation. Parts is assumed to be fixed to the electrode terminals.

  According to the battery of the present invention, since the holding portion and the electrode terminal are fixed with the insulating material sandwiched therebetween, the insulation between the holding portion and the electrode terminal is ensured by the insulating material. Furthermore, since the first taper portion of the holding portion and the third taper portion of the outer surface of the insulating material face each other and the base end side thereof has a large diameter, the force in the distal direction with respect to the electrode terminal or the insulating material can be reduced. Received by the taper. Further, since the second taper portion of the main body of the electrode terminal and the fourth taper portion of the insulating material face each other and the power generation element side has a small diameter, the force in the proximal direction with respect to the electrode terminal or the insulating material is reduced in the taper. Received by the department. Therefore, even if the internal pressure is greatly increased, the battery can ensure good terminal prevention, insulation and sealing.

Further, in the present invention, the insulating material and the holding portion are fixed to the electrode terminal by caulking the holding portion with respect to the electrode terminal at a position closer to the tip than any of the first to fourth tapered portions. It is desirable that
If it does in this way, an insulating material and a holding | maintenance part will be crimped and fixed to the electrode terminal outside the 1st-4th taper part. Therefore, a good retaining property is secured by the caulking portion, and a sealing property by the first to fourth tapered portions is secured.

Alternatively, in the present invention, a washer is attached to the tip of the electrode terminal and has a diameter larger than the diameter of the tip of the holding portion, and the tip of the insulating material protrudes outward from between the tip of the holding portion and the washer. The fixing of the insulating material and the holding portion to the electrode terminal may be performed by fixing the washer to the tip of the electrode terminal.
Even in such a case, a good insulating property is secured by the insulating material, and a good retaining property is secured by fixing the washer.

Further, in the present invention, the electrode terminal is provided with a flange portion located inside the case and having a diameter larger than the maximum diameter of the first taper portion, and a part of the surface of the flange portion on the main body side is made of an insulating material. It is desirable that a pressure receiving portion that is separated is provided.
In such a case, since the flange portion has a diameter larger than the maximum diameter of the first taper portion, even when a large outward force is applied to the electrode terminal from inside the case, the flange portion prevents the electrode terminal from coming off. Is done. Furthermore, since the pressure receiving portion is provided on a part of the surface of the flange portion on the main body side, the internal pressure is also applied to the pressure receiving portion. For this reason, inward force acts on the pressure receiving portion together with internal pressure that is outward force with respect to the electrode terminal. Since these cancel each other out, the force applied to the electrode terminal is reduced, and a better retaining property can be secured.

  According to the battery of the present invention, the battery has a terminal portion structure that can ensure good retaining property, insulating property, and sealing property even when the internal pressure is greatly increased.

"First form"
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is a can-structured secondary battery enclosed in a can case.

  As shown in FIG. 1, the secondary battery 1 of this embodiment includes an electrode body 11 that is a power generation element, a can case 12 that encloses the electrode body 11, and a lid portion 13 that is attached to the can case 12. Yes. Further, a positive electrode terminal 14 and a negative electrode terminal 14 projecting through the cover part 13 are attached. The electrode body 11 is formed by winding a positive electrode plate and a negative electrode plate with a separator sheet in between to form a flat shape. The can case 12 has a flat, substantially rectangular parallelepiped shape with a small thickness in the depth direction in the figure, and the upper surface in the figure is covered with a lid portion 13 and sealed. Therefore, the can case 12 and the lid portion 13 correspond to the case. An insulating resin 15 is sandwiched between the lid portion 13 and the terminal 14.

  Moreover, the lead | read | reed 16 connected to the positive electrode plate or negative electrode plate of the electrode body 11 is connected to the lower part of the terminal 14 in the figure, respectively. Furthermore, as shown in FIGS. 1 and 2, the terminal 14 of the secondary battery 1 is covered with an insulating resin 15 and a lid portion 13 at the base end portion. The terminal 14, the insulating resin 15, and the lid portion 13 are crimped together and fixed. FIG. 2 shows the periphery of the terminal 14 of FIG. 1 in a sectional view in the depth direction. Further, as shown in FIG. 2, the lid portion 13 is formed with a substantially cylindrical terminal fixing portion 17 for penetrating the terminal 14, and a first taper portion 18 that is widened at the base is formed. ing. This terminal fixing portion 17 corresponds to a holding portion.

  As shown in FIGS. 2, 3, and 4, both terminals 14 have a substantially cylindrical main body portion 21 and a flange portion 22. A caulking circular groove 23 is provided on the outer peripheral surface of the main body 21. In addition, on the surface of the flange portion 22 on the main body portion 21 side, four square grooves 24 are provided on the edges at positions that are 90 degrees from each other. A second taper portion 25 that narrows toward the flange portion 22 is provided on the outer periphery of the main body portion 21 near the flange portion 22. This square groove 24 corresponds to a pressure receiving portion.

  Moreover, the insulating resin 15 has a cylindrical portion 31, a flange portion 32, and a flange portion 33 as shown in FIG. Further, a third taper portion 34 that is widened toward the outer periphery is provided at the boundary between the cylindrical portion 31 and the flange portion 32. Further, on the inner peripheral side, a fourth tapered portion 35 is provided in a direction in which the hole diameter decreases toward the flange portion 32. The minimum diameter of the inner periphery of the fourth taper portion 35 is smaller than the maximum diameter of the outer periphery of the second taper portion 25 of the terminal 14. The cylindrical portion 31 is shorter than the main body portion 21 of the terminal 14 and slightly longer than the terminal fixing portion 17 of the lid portion 13. The flange 33 is formed with a notch 36 through which the lead 16 is passed. This insulating resin 15 is formed of a resin having a good insulating property such as PP or fluororesin.

  When the lid portion 13, the terminal 14, and the insulating resin 15 formed in this way are assembled, the main body portion 21 of the terminal 14 is press-fitted into the central through hole of the insulating resin 15. Further, the terminal 14 and the insulating resin 15 are inserted into the terminal fixing portion 17 of the lid portion 13. At this time, the outer shape of the terminal fixing portion 17 of the insulating resin 15 is a flat cylinder. By putting these together and crimping at the position of the circular groove 23 of the terminal 14, the terminal fixing portion 17 of the lid portion 13 and the cylindrical portion 31 of the insulating resin 15 are deformed and fixed as shown in FIG. The By this caulking, the terminal 14 is well retained against the vertical force in the figure.

  Further, the caulking in this way causes the insulating resin 15 to be sandwiched between the lid portion 13 and the terminal 14. At this time, since the cylindrical portion 31 of the insulating resin 15 is shorter than the main body portion 21 of the terminal 14 and longer than the terminal fixing portion 17 of the lid portion 13, the lid portion 13 and the terminal 14 are in direct contact with each other. There is no. Accordingly, the insulating resin 15 ensures good insulation between the lid portion 13 and the terminal 14. And since the front-end | tip part of the terminal 14 will protrude in the upper direction in FIG. 2 from the resin 15 for insulation, this secondary battery 1 can be connected and used for another apparatus by the terminal 14. FIG.

  Further, as a result of fixing in this manner, the third taper portion 34 of the insulating resin 15 and the first taper portion 18 of the lid portion 13 are held in pressure contact with each other. Further, the fourth taper portion 35 of the insulating resin 15 and the second taper portion 25 of the terminal 14 are held in pressure contact with each other. By the press contact, the lid portion 13 and the insulating resin 15 and the terminal 14 and the insulating resin 15 are brought into strong contact with the deformation of the insulating resin 15, respectively. Therefore, the terminal 14 is secured with a good sealing property by the insulating resin 15.

  Next, a case where an internal pressure is applied to the secondary battery 1 will be described. In general, the internal pressure gradually increases as gas is generated inside the secondary battery 1. Due to this internal pressure, the terminal 14 receives an upward force from the lower side in FIG. Further, the gas generated inside enters the square groove 24 from between the insulating resin 15 and the terminal 14. Therefore, at the portion of the square groove 24, the terminal 14 receives a downward force in the figure by the gas that has entered. These forces are opposite to each other in the square groove 24 and are canceled out. Therefore, the terminal 14 as a whole is not applied with a very large upward force due to the internal pressure.

  Furthermore, in the secondary battery 1, it will be described that good sealing performance is maintained even when the terminal 14 is slightly moved in the vertical direction due to internal pressure or vibration. First, when the terminal 14 moves in the upward direction in FIG. 2, the third tapered portion 34 of the insulating resin 15 is more strongly pressed against the first tapered portion 18 of the lid portion 13. Further, when the terminal 14 moves downward in the figure, the fourth tapered portion 35 of the insulating resin 15 is more strongly pressed against the second tapered portion 25 of the terminal 14. From these facts, it can be said that good sealing performance is maintained even when the terminal 14 moves in any direction.

  As described above in detail, according to the secondary battery 1 of the present embodiment, the cylindrical portion 31 of the insulating resin 15 and the terminal fixing portion 17 of the lid portion 13 are deformed, and the circular groove 23 of the terminal 14 is caulked. Therefore, it has a good retaining property. Further, since the insulating resin 15 covers the space between the lid portion 13 and the terminal 14, it has a good insulating property. Furthermore, since the insulating tape 15 is provided with a third taper portion 34 and a fourth taper portion 35, and these are in pressure contact with the second taper portion 25 of the terminal 14 and the first taper portion 18 of the lid portion 13, It has good sealing properties. For these reasons, the secondary battery 1 of the present embodiment is a battery having a terminal portion structure that can ensure good slip prevention, insulation, and sealing properties even when the internal pressure increases greatly.

"Second form"
Next, a second embodiment of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is a terminal structure provided in a can-structured secondary battery enclosed in a can case as in the first embodiment, and only the parts different from the first embodiment will be described here.

  In the terminal structure of the secondary battery of this embodiment, as shown in FIG. 6, it is fixed by screws 41 and washers 42 instead of caulking. Therefore, the terminal 14 is not provided with the circular groove 23. Instead, a screw hole 43 is provided on the upper surface of the main body 21 of the terminal 14 in the figure. The cylindrical portion 31 of the insulating resin 15 is formed longer than the main body portion 21 of the terminal 14.

  Also in the terminal structure of this embodiment, the terminal 14 is press-fitted into the insulating resin 15. Thereafter, the tip of the cylindrical portion 31 of the insulating resin 15 is heated, and is deformed by being pressed and pushed open by the washer 42. Further, the screw 41 is screwed into the screw hole 43 to fix the washer 42. Accordingly, the washer 42 is pressed and fixed to the terminal fixing portion 17 of the lid portion 13 with the tip portion of the insulating resin 15 interposed therebetween. Therefore, good retaining properties and insulation properties are ensured. Further, the screwing intensifies the press contact between the lid portion 13 and the insulating resin 15 and between the terminal 14 and the insulating resin 15. Therefore, good sealing performance is also ensured.

  As explained in detail above, the terminal structure of the secondary battery of this embodiment also ensures a good retaining property, insulating property, and sealing property even when the internal pressure increases significantly, as in the first embodiment. The battery has a terminal part structure that can be made.

In addition, each said form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, in each of the above embodiments, four square grooves 24 are formed in the flange portion 22 of the terminal 14, but the present invention is not limited to four places. A larger number of square grooves may be provided, or a larger groove may be provided in a small number of places. Further, each square groove may be formed up to the boundary between the flange portion 22 and the main body portion 21 or further to the inner peripheral side. Moreover, it may replace with a square groove and the circular-arc-shaped groove | channel along the outer periphery of the flange part 22 may be sufficient. Or as shown in FIG. 7, the level | step difference 45 formed 360 degrees along the outer periphery of the flange part 22 may be sufficient. Also, it is not necessarily 360 degrees.
Further, for example, instead of forming the square groove 24 in the flange portion 22, a pressure receiving portion is provided between the flange portion 22 and the insulating resin 15 by fitting a suitable outer peripheral washer or the like into the flat flange portion. You can also.
Further, for example, in the first embodiment, the circular groove 23 is formed in the terminal 14 in advance. However, the circular groove 23 may be formed by caulking.
For example, in the second embodiment, the upper end portion of the insulating resin 15 may be formed in an open shape in advance.

It is a fragmentary sectional view which shows schematic structure of the secondary battery of a 1st form. It is sectional drawing which shows schematic structure of a terminal part. It is a perspective view which shows a terminal. It is a top view which shows a terminal. It is a perspective view which shows resin for insulation. It is sectional drawing which shows schematic structure of the terminal part of the secondary battery of a 2nd form. It is a perspective view which shows another example of a terminal.

Explanation of symbols

1 Secondary battery (battery)
11 Electrode body (power generation element)
12 Can case
13 Lid (case)
14 terminals (electrode terminals)
15 Insulating resin (insulating material)
17 Terminal fixing part (holding part)
18 First taper part 21 Body part 22 Flange part 24 Square groove (pressure receiving part)
25 Second taper part 34 Third taper part 35 Fourth taper part 42 Washer

Claims (4)

In the battery in which the power generation element is housed in the case and the electrode terminal connected to the power generation element protrudes outside through the case,
A cylindrical holding part that penetrates the electrode terminal is provided outwardly in a part of the case, and a first taper part having a large diameter at the base end side is provided at the base part,
In the electrode terminal,
A body portion that penetrates the holding portion and protrudes to the outside;
A second taper portion located on the outer peripheral surface of the main body portion and having a small diameter on the power generation element side;
A cylindrical insulating material is sandwiched between the holding portion and the electrode terminal,
In the insulation material,
A third taper portion on the outer surface facing the first taper portion and having a proximal end having a large diameter ;
A fourth taper portion on the inner surface facing the second taper portion and having a small diameter on the power generation element side ;
The battery, wherein the insulating material and the holding portion are fixed to the electrode terminal. The battery according to claim 1,
The insulating material and the holding portion are fixed to the electrode terminal by caulking the holding portion with respect to the electrode terminal at a position closer to the tip than any of the first to fourth tapered portions. A battery characterized by having The battery according to claim 1,
Attached to the tip of the electrode terminal, having a washer larger in diameter than the tip of the holding portion;
The tip of the insulating material protrudes outward from between the tip of the holding part and the washer;
The battery, wherein the insulating material and the holding portion are fixed to the electrode terminal by fixing the washer to a tip of the electrode terminal. In the battery according to any one of claims 1 to 3,
The electrode terminal is provided with a flange portion located inside the case and having a diameter larger than the maximum diameter of the first taper portion,
A battery, wherein a pressure receiving portion that is separated from the insulating material is provided on a part of the surface of the flange portion on the body portion side.

Images