JP2012114004A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery penetrating an exterior package and fixing an outside terminal while projecting outward, which has an excellent sealing property at a fixing portion of the exterior package and the outside terminal.SOLUTION: A battery 10 comprises an exterior package 30, outside terminals 40 and 40, and an insulation member 50. The battery 10 further comprises burring portions 34 and 34 projecting toward the outside of the exterior package 30, and reinforcing rings 35 and 35 disposed on an outer peripheries of the burring portions 34 and 34. The burring portion 34 is pressed to plastically deform, and compression force is generated between the outside terminal 40 and the exterior package 30 by a part (a bulging portion 34a) of the plastically deformed burring portion 34 to fix the outside terminal 40. The outside terminal 40 is equipped with a reservoir groove 42 formed over the entire outer periphery of the outside terminal 40 and tilting to the inner side of the exterior package 30, on the outer side of the exterior package 30 rather than a place receiving the compression force caused by pressing the burring portion 34.

Description

  The present invention relates to a battery, and more particularly to a technique for fixing an external terminal to an exterior.

  The exterior of the battery houses the power generation element of the battery. External terminals (a positive electrode terminal and a negative electrode terminal) that pass through the exterior and project outward are fixed to the outer surface of the exterior. The external terminal is electrically connected to the power generation element, and power is exchanged between the inside and outside of the battery through the external terminal.

When the battery is a non-aqueous electrolyte battery such as a lithium ion secondary battery, it is known that battery performance is affected when moisture enters the battery. For this reason, it is necessary to make the sealing degree of a battery sufficiently high.
Furthermore, in the external terminal and the exterior fixing part, the external terminal does not fall out from the battery, and the electrolyte inside the battery or the gas generated inside the battery does not leak from the periphery of the external terminal. In addition, insulation between the external terminal and the exterior is required. That is, there is a demand for ensuring a sufficient sealing property between the exterior and the external terminal.

In Patent Document 1, in a battery in which an external terminal protrudes from an outer lid portion, an insulating member is interposed between the lid portion and the external terminal, and a burring portion is provided around the insulating member in the lid portion. A technique for fastening and fixing an external terminal by pressing and crimping the burring portion from a direction orthogonal to the protruding direction of the burring portion is disclosed.
However, if the cooling and heating cycle is repeated with repeated use of the battery, the caulking fastening part gradually loosens due to the action of trying to return to the shape before caulking, the sealing performance deteriorates, and the exterior and The sealing performance of the fixed part of the external terminal may be insufficient.

JP 2005-302625 A

  An object of the present invention is to provide a battery excellent in sealing performance at a fixing portion between an exterior and an external terminal in a battery that fixes the external terminal in a state of penetrating the exterior and protruding outward.

  The battery of the present invention includes an exterior having a through-hole, an external terminal fixed to the through-hole of the exterior in a state in which a part projects outward from the exterior, and an interposition between the exterior and the external terminal. An insulating member, a burring portion located at the periphery of the through-hole of the exterior, projecting outward of the exterior, and disposed on the outer periphery of the burring portion. A reinforcing member that reinforces, presses the burring portion to cause plastic deformation, and generates a compression force between the external terminal and the through hole by a part of the plastically deformed burring portion. The external terminal is fixed to the through hole by the external terminal, and the external terminal is provided with a groove on the outer side of the exterior of the portion receiving the pressing force by the press on the burring portion.

  The groove is preferably formed over the entire outer periphery of the external terminal.

  It is preferable that the bottom of the groove be inclined inward of the exterior.

  Preferably, the external terminal further includes an airtight groove having an edge line at a position corresponding to a press lower end to the burring portion, and a bottom portion of the groove is continuously provided from the edge line of the airtight groove.

  ADVANTAGE OF THE INVENTION According to this invention, the battery excellent in the sealing performance in the fixing | fixed part of an exterior and an external terminal can be provided.

It is a figure which shows schematic structure of a battery. It is an expanded sectional view which shows the fixing | fixed part of an exterior and an external terminal. It is a figure which shows the form of an external terminal. It is a figure which shows the clearance gap between the external terminal and insulation member which may arise at the time of fixation of an external terminal.

With reference to FIG. 1, a schematic configuration of a battery 10 which is an embodiment of the battery according to the present invention will be described. The battery 10 of this embodiment is a lithium ion secondary battery.
The battery 10 includes a power generation element 20, an exterior 30 that houses the power generation element 20, external terminals 40 and 40 that protrude outward from the exterior 30, and between the external terminals 40 and 40 and the exterior 30. Insulating members 50 and 50 interposed.

  The power generation element 20 is obtained by impregnating an electrolytic solution into an electrode body formed by laminating or winding a positive electrode, a negative electrode, and a separator. When the battery 10 is charged / discharged, a chemical reaction occurs in the power generation element 20 (strictly speaking, ion movement occurs between the positive electrode and the negative electrode via the electrolytic solution), thereby generating a current flow.

  The exterior 30 is a square can having a storage portion 31 and a lid portion 32. The storage unit 31 is a bottomed cylindrical member having an open surface, and stores the power generation element 20 therein. The lid portion 32 is a flat member having a shape corresponding to the opening surface of the storage portion 31 and is joined to the storage portion 31 in a state where the opening surface of the storage portion 31 is closed.

The external terminals 40 and 40 are arranged in a state where a part of the external terminals 40 protrudes outward from the battery 10 from the outer surface of the lid portion 32. The external terminals 40 and 40 are electrically connected to the positive electrode or the negative electrode of the power generation element 20 via current collecting terminals 45 and 45. The external terminals 40 and 40 and the current collecting terminals 45 and 45 function as an energization path for taking out the electric power stored in the power generation element 20 to the outside or taking in electric power from the outside into the power generation element 20.
Each current collecting terminal 45 is connected to the positive electrode plate and the negative electrode plate of the power generation element 20. As a material of the current collecting terminal 45, for example, aluminum can be used on the positive electrode side and copper on the negative electrode side.

  The external terminal 40 is threaded by thread rolling at a portion protruding outward of the battery 10 to form a bolt portion. When the battery 10 is actually used, a bus bar, a connection terminal of an external device, and the like are fastened and fixed to the external terminal 40 using the bolt portion. When fastening and fixing, since external torque is applied to the external terminal 40 and external force is applied in the axial direction by screw fastening, it is preferable to employ a high-strength material such as iron as the material of the external terminal 40.

The external terminals 40 and 40 are fixed to the lid portion 32 through insulating members 50 and 50. The insulating member 50 is wound around the external terminal 40 to electrically insulate the exterior 30 from the external terminal 40.
The material of the insulating member 50 is preferably a material having excellent high-temperature creep characteristics, that is, a material having long-term creep resistance against the cooling cycle of the battery 10, and examples thereof include PEEK (polyether ether ketone).

Below, with reference to FIG. 2, the fixed form of the exterior | packing 30 and the external terminal 40 is demonstrated.
As shown in FIG. 2A, the exterior 30 has through-holes 33 and 33 through which the external terminals 40 and 40 can penetrate, and a burring portion that protrudes toward the outside of the exterior 30 around each through-hole 33. 34 is formed.

The through hole 33 is a hole having a predetermined inner diameter, and penetrates in the thickness direction of the exterior 30.
The burring part 34 is a thick-walled part that protrudes vertically from the inner side to the outer side of the exterior 30 at the periphery of the through-hole 33. The burring part 34 is a thick portion formed by plastic processing a part of the exterior 30 and is appropriately formed by a known burring process, a deep drawing method, a close-up method, or a combination thereof.

A reinforcing ring 35 is fitted to the outer peripheral portion of the burring portion 34.
The reinforcing ring 35 is a ring-shaped member formed of a metal material (for example, iron) having a strength higher than that of the material constituting the exterior 30 (the lid portion 32), and has a strength against an external force applied in the radial direction of the burring portion 34. It is the reinforcement member to reinforce. The inner diameter of the reinforcing ring 35 is formed substantially the same as the outer diameter of the burring portion 34.

As described above, the insulating member 50 also functions as a member for ensuring airtightness inside the battery 10 in addition to the insulating property for insulating the exterior 30 and the external terminal 40.
Specifically, as shown in FIG. 2B, the external terminal 40 around which the insulating member 50 is wound is disposed in the through hole 33, and the inner peripheral portion of the protruding side end surface of the burring portion 34 is pressed. By crimping, a bulging portion 34 a bulging from the inner peripheral side surface of the burring portion 34 toward the radially inner side is formed.
At this time, the reinforcing ring 35 made of a material stronger than the burring portion 34 is disposed on the outer peripheral side of the burring portion 34, thereby preventing the pressing force during caulking from being relaxed to the outside. Therefore, the bulging portion 34a bulges toward the inner side (external terminal 40 side).

The bulging portion 34 a bulging inwardly presses the insulating member 50, and this pressing force is applied as a surface pressure to the insulating member 50. A portion of the insulating member 50 to which the surface pressure is applied by the bulging portion 34 a is elastically deformed inward, and an external force generated by the elastic deformation is applied as a surface pressure to the external terminal 40.
In this manner, the inner peripheral portion of the end surface of the burring portion 34 is pressed from above and caulked to form a bulging portion 34a that bulges inward, and the surface pressure from the bulging portion 34a causes the insulating member 50 to And transmitted to the external terminal 40. The external terminal 40 is pressed by the surface pressure and fixed to the through hole 33 of the lid portion 32.
At this time, since the bulging portion 34a is plastically deformed in a direction orthogonal to the pressing direction and fastens and fixes the insulating member 50 and the external terminal 40, the space between the exterior 30, the insulating member 50, and the external terminal 40 is fixed. It is possible to apply a strong surface pressure and frictional force. Therefore, even if it receives the cooling / heating cycle at the time of using the battery 10, the bulging part 34a is hard to deform | transform and a fixing | fixed part does not loosen.

An airtight groove 41 is formed in the midway portion of the external terminal 40 in the axial direction. The airtight groove 41 is a semicircular groove (or a shape having an edge line at the groove end, such as a semi-elliptical shape) formed along the circumferential direction of the external terminal 40 along the entire outer periphery thereof. The groove width is as follows.
As the insulating member 50 is elastically deformed as described above and enters the airtight groove 41 of the external terminal 40 and bites into the edge line of the airtight groove 41, the insulating member 50 and the external terminal 40 are firmly adhered, Airtightness is ensured.
In addition, it is preferable to set the lower end of the press and the outer edge line of the airtight groove 41 at substantially the same position when pressing the end surface of the burring portion 34, thereby reducing the amount of plastic deformation of the bulging portion 34 a. The edge line of the airtight groove 41 is positioned at the largest position, and the degree of adhesion between the insulating member 50 and the external terminal 40 can be improved efficiently.

As shown in FIG. 3, the accumulation groove 42 that is inclined toward the inner side (downward in the drawing) of the exterior 30 on the outer side (upward in the drawing) of the exterior 30 than the airtight groove 41 in the external terminal 40. Is formed.
The accumulation groove 42 is formed over the entire outer peripheral surface of the external terminal 40, and is above the upper edge line of the airtight groove 41, which is a seal point at the fixing portion between the external terminal 40 and the exterior 30, in other words. The burring portion 34 is formed above a portion (press lower end) that receives a pressing force by pressing.
As described above, the external terminal 40 has the airtight groove 41 at a position corresponding to the lower end of the press to the burring portion 34, and is formed immediately above the airtight groove 41, that is, from the upper edge line of the airtight groove 41. It has the accumulation groove | channel 42 which has the bottom part formed continuously.

The accumulation groove 42 is a recess provided inward from the outer peripheral surface of the external terminal 40 and opens to the outer peripheral side surface of the external terminal 40.
The bottom of the accumulation groove 42 has a shape that inclines downward as it goes inward from the outer peripheral surface of the external terminal 40. In the case of the battery 10 according to the present embodiment, the external terminals 40 and 40 are used in a state of being installed so as to protrude vertically upward. It will incline toward the direction in which gravity acts as it goes inside. At this time, it is preferable that the downward inclination angle of the bottom portion of the accumulation groove 42 is set to a size that reliably inclines downward even when an error occurs in the installation angle of the battery 10 in use.

  By pressing the burring portion 34, the bulging portion 34 a bulging toward the inner peripheral side presses the insulating member 50. At this time, the location where the bulging portion 34 a presses the insulating member 50 is the lower end of the press, that is, the axially intermediate portion of the insulating member 50. For this reason, as shown in FIG. 4, the upper part of the insulating member 50 is deformed in a direction opposite to the direction of receiving the compression force, and the upper part of the insulating member 50 is deformed so as to spread outward in the radial direction. There is a possibility that a minute gap G is generated between the terminals 40.

In the present embodiment, by forming the accumulation groove 42 above the airtight groove 41 that serves as a seal point between the exterior 30 and the external terminal 40, moisture mixed in the gap G, for example, the outer peripheral surface of the external terminal 40 is covered. Moisture that enters from the outside of the battery 10, such as falling condensed water, can be collected and stored in the groove 42. The water temporarily stored in the accumulation groove 42 is evaporated by the cooling / heating cycle of the battery 10.
In this way, by collecting the water that has entered the gap G and collecting the moisture in the groove 42, corrosion of the external terminal 40 due to the water can be prevented. Therefore, troubles caused by corrosion of the external terminal 40 (for example, a gap is generated between the external terminal 40 and the insulating member 50 and airtightness is reduced) can be prevented, and the fastening portion of the external terminal 40 with respect to the exterior 30 can be prevented. This can contribute to improving the sealing performance.

In addition, by forming the accumulation groove 42 over the entire outer periphery of the external terminal 40, it is possible to reliably collect moisture that falls along the outer peripheral surface of the external terminal 40.
Furthermore, by providing the bottom of the reservoir groove 42 so as to incline toward the inner side of the exterior 30, the moisture that has entered the reservoir groove 42 moves downward along the inclination and is stored therein. The collection space by the pool groove 42 can be sufficiently secured.

In particular, by continuously forming the collecting groove 42 from the upper edge line of the airtight groove 41 serving as a seal point toward the upper side, all moisture mixed into the gap G from the outside is collected in the collecting groove 42. can do. For this reason, corrosion of the upper edge line of the airtight groove 41 can be prevented, the deterioration of the sealing performance of the exterior 30 and the external terminal 40 can be prevented, and the life of the battery 10 during actual use can be improved.
Further, by forming the bottom portion of the collecting groove 42 continuously from the edge line of the airtight groove 41, the acute angle effect of the upper edge line of the airtight groove 41 can be increased, and the biting degree of the insulating member 50 is increased. Therefore, the sealing effect in the airtight groove 41 is increased.

  The reservoir groove 42 is not limited to a configuration provided above the airtight groove 41, and a plurality of reservoir grooves 42 may be formed along the axial direction of the external terminal 40. In this case, the moisture collection space can be increased, and the reliability with respect to the sealing performance can be improved.

DESCRIPTION OF SYMBOLS 10 Battery 30 Exterior 34 Burring part 40 External terminal 41 Airtight groove 42 Reservation groove (groove)
50 Insulating material

Claims (4)

An exterior having a through hole;
An external terminal fixed to the through-hole of the exterior in a state in which a part protrudes outward of the exterior;
An insulating member interposed between the exterior and the external terminal;
A burring part located at the periphery of the through-hole of the exterior and protruding outward of the exterior;
A reinforcing member disposed on the outer periphery of the burring portion and reinforcing the strength of the burring portion toward the outer periphery;
A battery in which the burring portion is pressed and plastically deformed, and a compression force is generated between the external terminal and the through hole by a part of the plastically deformed burring portion to fix the external terminal to the through hole. Because
The battery in which the external terminal has a groove on the outer side of the exterior rather than a portion that receives a pressing force by pressing on the burring portion.   The battery according to claim 1, wherein the groove is formed over the entire outer periphery of the external terminal.   The battery according to claim 1, wherein a bottom portion of the groove is inclined inward of the exterior. The external terminal further includes an airtight groove having an edge line at a position corresponding to a lower end of the press to the burring portion,
The battery according to claim 1, wherein the bottom of the groove is continuously provided from an edge line of the hermetic groove.

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