JP4326381B2 - battery - Google Patents

Description

  The present invention relates to a chargeable / dischargeable non-aqueous electrolyte secondary battery, specifically a battery such as a lithium ion secondary battery, which is mainly used as a power source for portable electronic devices such as video cameras, mobile computers, and cellular phones.

  In recent years, chargeable / dischargeable non-aqueous electrolyte secondary batteries, such as lithium ion secondary batteries, are mainly used as power sources for portable electronic devices such as video cameras, mobile computers, and mobile phones that are rapidly spreading.

  By the way, in a lithium ion secondary battery (hereinafter simply referred to as a battery), a protection circuit for controlling the battery voltage is provided outside in order to prevent overcharge and overdischarge. For example, a configuration in which the battery pack is actually mounted on an electronic device as a battery pack housed in a synthetic resin outer case is employed. By the way, the protective circuit and the battery are electrically connected by a lead plate for connection. As the lead plate, the electrical size of the battery in the outer case is of course as well as the electrical connectivity with the protective circuit. In other words, in order to make the outer case as small as possible with respect to the size of the battery, a nickel material or a stainless steel material plated with nickel on the surface is used in the form of a plate material. .

  FIG. 8 shows a schematic exploded perspective view of a general configuration example of a conventional battery pack. In the battery pack, a rectangular parallelepiped battery case 11 is accommodated in a synthetic resin rectangular parallelepiped outer case 30 that is slightly larger than that. The exterior case 30 is composed of a rectangular parallelepiped first exterior case half 31 and a second exterior case half 32 that are open on one side. The outer case halves 31 and 32 are formed to have the same outer dimensions on one open side, and the battery case 11 and other circuits are placed inside the open case in a state where the open one side faces each other. A cavity that can accommodate the like is formed.

  The battery case 11 is made of aluminum or an aluminum alloy, and a nonaqueous electrolyte secondary battery including a power generation element in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, specifically a lithium ion secondary battery or the like. A secondary battery 10 is accommodated. A negative electrode terminal 33 insulated from the battery case 11 is formed on one side surface (bottom surface in FIG. 8) of the battery case 11, and the entire battery case other than the portion where the negative electrode terminal 33 is provided serves as a positive electrode terminal. .

  A protective circuit board 34 is attached to the side surface (upper surface in FIG. 8) of the battery case 11 that faces the one side surface where the negative electrode terminal 33 described above is provided. The protection circuit board 34 is a board provided with a protection circuit for preventing overcharge or overdischarge of the battery 10. The protection circuit board 34 has a circuit element (not shown) mounted on the surface (the lower surface in FIG. 8) facing the battery case 11, and the opposite side, that is, the outer surface (in FIG. 8). On the upper surface), positive and negative electrode terminals 34a for taking out electric power to the outside and conversely taking in electric power from outside for charging are projected. Further, a through hole 31a is formed on one side surface (upper surface in FIG. 8) of the first exterior case half 31 so that the output terminal 34a of the protection circuit board 34 penetrates and the tip part protrudes slightly. .

  The protective circuit board 34 is fixed to the clad plate 12 fixed to the battery case 11 that also serves as the positive electrode terminal of the battery 10 via the positive electrode lead plate 20 made of nickel. One surface of the clad plate 12 is fixed to the side surface to which the protection circuit board 34 of the battery case 11 is attached by welding, and the other surface is fixed to the positive electrode lead plate 20 by welding. Therefore, the positive electrode lead plate 20 is fixed to the battery case 11 via the clad plate 12.

  Further, the protection circuit board 34 is also connected to the negative electrode terminal 33 of the battery 10 through a negative electrode lead plate 22 made of nickel and a PTC (Positive Temperature Coefficient) element 28. The PTC element 28 is a protective element that cuts off a circuit when the temperature of the battery 10 is abnormally increased and becomes high resistance in response to the temperature.

  The negative electrode lead plate 22 has both side surfaces for connecting between the side surface (bottom surface in FIG. 8) provided with the negative electrode terminal 33 of the battery case 11 and the side surface (top surface in FIG. 8) provided with the protection circuit board 34. It is provided along one side surface (front side in FIG. 8). However, since the battery case 11 as a whole other than the negative electrode terminal 33 also serves as a positive electrode terminal, an insulating sheet 16 is interposed between the negative electrode lead plate 22 and the PTC element 28 and the battery case 11 to prevent a short circuit. ing.

  The battery case 11 to which the protective circuit board 34 is connected has a double-sided adhesive tape 35 in a cavity formed when the protective circuit board 34 and the through-holes 31a are aligned and the outer case halves 31 and 32 are combined. It is fixed and accommodated. Then, the two outer case halves 31 and 32 are fixed to each other by bonding, heat welding, ultrasonic welding, or the like to form one box-like container, whereby the electrode terminal 34a is inserted into the through hole 31a of the outer case 30. Is formed. Normally, products are distributed in the state of this battery pack, and are mounted on various electronic devices in the state of such a battery pack.

  By the way, the positive electrode lead plate 20 made of nickel is fixed to the battery case 11 which also serves as the positive electrode terminal via the clad plate 12 except for the portion where the negative electrode terminal 33 is formed. According to the following. That is, the positive lead plate 20 is directly fixed to the battery case 11 by welding because the battery case 11 is made of aluminum or an aluminum alloy, and thus the resistance of the battery case 11 is good in resistance welding. Also, in the ultrasonic welding method, the positive electrode lead plate 20 is made of nickel (or made of stainless steel) and is not melted.

  Under such circumstances, conventionally, a laser welding method has been employed to fix the positive electrode lead plate 20 to the battery case 11. However, when the laser welding method is used, the environmental conditions of use are markedly restricted, the apparatus is expensive, and the productivity is low, leading to an increase in the manufacturing cost of the battery (battery pack). was there.

In order to solve such problems, the conventional technology as described above, that is, one layer made of aluminum or an aluminum alloy of the clad plate 12 having a two-layer structure is resistance-welded to the battery case 11 and nickel of the clad plate is obtained. Patent Document 1 discloses an invention in which the other made layer is resistance welded to the positive electrode lead plate 20 made of nickel. Further, Patent Document 2 discloses an invention in which insert molding is performed instead of welding another kind of metal to the outer surface of an aluminum can such as the battery case 11.
JP 09-330696 A US Pat. No. 4,792,081

  By the way, in the invention disclosed in Patent Document 1 described above, the clad plate is fixed to the outer surface of the battery case by welding, and the positive electrode lead plate is further fixed to the clad plate by welding. There is a problem that the internal cavity of the outer case cannot be effectively used by the thickness, in other words, if the size of the outer case is the same, the battery case needs to be reduced by the thickness of the clad plate. This is very disadvantageous, for example, for a battery (battery pack) for a mobile phone that requires extreme miniaturization.

  In addition, in the invention disclosed in Patent Document 2, the manufacturing process becomes complicated, and when another metal is insert-molded on an aluminum plate before deep drawing, and then deep drawing is performed, There is also a problem that it is difficult to strictly control the position of another type of metal in the bottom of the aluminum can to be manufactured so that variations do not occur, and further, the position where the different type of metal is molded becomes unclear. is there.

  The present invention has been made in view of such circumstances, and it is mainly intended to eliminate the need to consider the thickness of a clad plate in a battery in which a battery case and a positive electrode lead plate are fixed via a clad plate. Objective.

  In short, the present invention adopts a configuration in which a connecting member interposed between the two in order to fix the positive electrode lead plate to the battery case by welding is disposed in a recess provided in the battery case.

According to a first aspect of the battery of the present invention, there is provided a battery case made of a first metal containing a power generation element, a second metal current extraction lead plate for taking out current from the power generation element, a battery case, the battery that includes a connecting member and the other surface is fixed to each of the current extraction lead plate, the battery case by deep drawing, Ri Na formed to have a recess in the surface The connecting member is fixed in the recess so that the other surface is made of a metal that can be welded to the second metal and is flush with the outer surface of the battery case. Features.

  In the first invention of the battery according to the present invention, the connecting member in which the second metal current extraction lead plate and the weldable metal are on the outer surface side of the battery case is the outer surface of the battery case. It is fixed in a recess formed on the surface of the battery case so as to be flush with each other.

  According to a second aspect of the battery of the present invention, in the first aspect of the battery described above, the connection member is configured so that the one surface is a surface of a metal layer that can be welded to the first metal. The other surface is a clad material configured to be a surface of a metal layer that can be welded to the second metal.

  In the second invention of the battery according to the present invention as described above, in the first invention described above, the connecting member is a clad plate composed of two layers, and the surface of one layer is a metal that can be welded to the first metal. The surface of the other layer becomes a metal layer that can be welded to the second metal.

  The battery according to a third aspect of the present invention is the battery according to the first aspect of the present invention, wherein the connecting member is formed in the recess by plating, sputtering or vapor deposition of a metal that can be welded to the second metal. It is characterized by being.

  In the third invention of the battery according to the present invention as described above, in the first invention of the battery described above, the connection member is formed in the recess by plating, sputtering or vapor deposition, and the material can be welded to the second metal. It is a new metal.

  According to the first aspect of the battery of the present invention, the outer surface of the connecting member for fixing the battery case and the positive electrode lead plate, which are conventionally fixed to the outer surface of the battery case, is the outer surface of the battery case. Since they are flush, it is not necessary to reduce the size of the battery by the thickness of the connecting member. In other words, if the size of the battery case is the same, the outer case can be reduced by the thickness of the connecting member.

  According to the second aspect of the battery of the present invention, in the first aspect described above, the connecting member is a clad plate composed of two layers, and the surface of one of the layers is a battery made of a first metal. The surface of the metal layer that can be welded to the case and the surface of the other layer become the metal layer that can be welded to the positive electrode lead plate made of the second metal. It can be easily welded and fixed by any method such as sonic welding, laser welding or resistance welding.

  Further, according to a third aspect of the battery of the present invention, in the first aspect, the connecting member is formed in the recess by plating, sputtering or vapor deposition, and the material is a current extraction made of the second metal. Because it is a metal that can be welded to the lead plate for welding, the positive electrode lead plate can be easily welded and fixed to the connecting member fixed to the battery case by any method such as ultrasonic welding, laser welding, resistance welding, etc. Is possible.

  Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic external perspective view of a battery case of a battery according to the present invention. The overall configuration of the battery pack is the same as that of the conventional example shown in FIG. The battery according to the present invention is different from the conventional example shown in FIG. 8 only in the method for fixing the clad plate 12 to the battery case described below. Therefore, in the following, a configuration for fixing the clad plate 12 to the battery case 11 will be mainly described.

As shown in FIG. 1, in the battery case 11 of the battery according to the present invention, a concave shape is formed on the inner side of the battery case 11 corresponding to the portion to which the clad plate 12 of FIG. A recess 13 is provided. The recess 13 is formed by reducing the thickness of the corresponding portion of the battery case 11 as shown in the schematic cross-sectional view of FIG. 2 (a), or as shown in the schematic cross-sectional view of FIG. 2 (b). by forming the relevant part of the case 11 in a concave shape and it is machined so as to be concave to the inside of the battery case 1 1.

Specifically, in the example shown in FIG. 2A, the recess 13 can be formed simultaneously with the battery case 11 itself. That is, it is possible to form the recess 13 according to the shape of the mold when the battery case 11 is formed by, for example, deep drawing from one aluminum plate .

In the example shown in FIG. 2B, the battery case 11 itself can be formed at the same time. That is, as in the case of FIG. 2A described above, the recess 13 is formed in accordance with the shape of the mold when the battery case 11 is formed by, for example, a single aluminum plate by deep drawing. Is possible .

  FIG. 3 is a schematic external perspective view of the battery case of the battery according to the present invention showing a state in which the clad plate 12 is fixed to the recess 13 formed in the battery case 11 as described above, and FIG. 4 is a schematic sectional view of the same. It is. As shown in these drawings, a clad plate 12 is fixed to a battery case 11 of a battery according to the present invention in a state of being fitted in a recess 13 formed on the surface thereof. As a method for fixing the clad plate 12 to the recess 13 of the battery case 11, ultrasonic welding, laser welding, resistance welding, or the like can be used.

  The clad plate 12 has a two-layer structure as in the conventional example described above, and one layer 12a on the battery case 11 side is a metal layer of aluminum or aluminum alloy, and the other layer on the opposite side to the battery case 11 is. 12b is a nickel metal layer. Therefore, one layer 12a made of aluminum or aluminum alloy of the clad plate 12 is fixed to the battery case 11 by welding, and the other layer 12b made of nickel is a positive electrode lead plate 20 similar to the conventional example shown in FIG. (Not shown) and fixed by welding. Thereby, the clad plate 12 functions as a connection member between the battery case 11 and the positive electrode lead plate 20.

  FIG. 5 is a schematic external perspective view of a battery case showing another embodiment of the battery according to the present invention. In this embodiment, the recess 13 is formed in the battery case 11 in the same manner as in the above-described embodiment. However, the clad plate 12 is not fitted and fixed to the formed recess 13, but the recess 13 13 is subjected to nickel plating. However, the same effect can be obtained not by plating but also by sputtering or vapor deposition.

  Specifically, as shown in FIG. 5, a portion other than the recess 13 of the battery case 11 in which the recess 13 is formed is masked with an appropriate masking material 14. Then, as shown in the schematic diagram of FIG. 6, the battery case 11 is dipped in the plating solution 51 in the plating tank 50 while being held by the hanger 52 with the surface on which the concave portion 13 is formed on the lower side.

  As a result, as shown in the schematic external perspective view of FIG. 7, the plated nickel layer 15 is formed in the recess 13 formed in the battery case 11, and this nickel layer 15 is fixed to the battery case 11. Has been. Accordingly, the nickel layer 15 functions as a connecting member between the battery case 11 and the positive electrode lead plate 20. A positive electrode lead plate 20 (not shown) similar to that of the conventional example shown in FIG. 8 is fixed to the nickel layer 15 by welding. The nickel layer plated on the recess 13 needs to be plated so as to be flush with the outer surface of the battery case 11. This is not limited to the case of plating, and the same applies to the case of sputtering or vapor deposition.

  As described in detail above, according to the battery of the present invention, the connection member for fixing the battery case and the positive electrode lead plate is conventionally fixed to the outer surface of the battery case. Since the outer surface is configured to be flush with the outer surface of the battery case, it is not necessary to reduce the size of the battery by the thickness of the connection member. In other words, if the size of the battery case is the same, the outer case can be reduced by the thickness of the connecting member.

  In addition, since the connecting member is a clad plate made of two layers of metal, one metal layer is used as a battery case, and the other metal layer is used as a positive electrode lead plate, such as ultrasonic welding, laser welding, resistance welding, etc. It can be easily welded and fixed by the method.

  Further, since the connecting member is formed in the recess by plating, sputtering or vapor deposition, and the material thereof is a metal that can be welded to the lead plate for current extraction made of the second metal, the positive electrode lead plate is used as the connecting member of the battery case. On the other hand, it can be easily welded and fixed by any method such as ultrasonic welding, laser welding or resistance welding.

  In the above-described embodiment, the battery case 11 is formed by deep drawing an aluminum plate, but the present invention can of course be applied to the battery case 11 formed by other processing methods. . In the above-described embodiment, the description has mainly been made on the configuration in which the clad plate 12 is fixed to the battery case 11, but it goes without saying that the battery case 11 itself can be applied to the battery pack of the prior art shown in FIG. 8. Yes.

It is a typical external appearance perspective view of the battery case of the battery which concerns on this invention. It is typical sectional drawing of the principal part of FIG. It is a typical external appearance perspective view which shows the state which fixed the clad board to the recessed part formed in the battery case of the battery which concerns on this invention. FIG. 4 is a schematic cross-sectional view of a main part of FIG. 3. It is a typical external appearance perspective view of the battery case which shows other embodiment of the battery which concerns on this invention. FIG. 6 is a schematic diagram showing a state in which plating is performed on a recess formed in the battery case of the battery according to the present invention shown in FIG. 5. It is a typical external appearance perspective view which shows the state which plated the recessed part formed in the battery case of the battery which concerns on this invention shown in FIG. It is a typical exploded perspective view which shows the general structural example of the conventional battery pack.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Battery 11 Battery case 12 Cladding plate 12a One layer of clad plate b 12b The other layer of clad plate 15 Nickel layer 20 Positive electrode lead plate 122c-124c Cutting line

Claims (3)

A first metal battery case containing a power generation element; a second metal current extraction lead plate for extracting current from the power generation element; one surface for the battery case; and the other surface for the current extraction. In a battery including a connection member fixed to each lead plate,
The battery case by deep drawing, Ri Na formed to have a recess in the surface,
The connection member is configured such that the other surface is made of a metal that can be welded to the second metal, and is fixed in the recess so as to be flush with the outer surface of the battery case. Battery.   The connecting member is configured such that the one surface is a surface of a metal layer weldable to the first metal and the other surface is a surface of a metal layer weldable to the second metal. The battery according to claim 1, wherein the battery is a clad material.   2. The battery according to claim 1, wherein the connection member is formed in the recess by plating, sputtering, or vapor-depositing a metal that can be welded to the second metal.

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