JP2014170757A - Square-shaped secondary battery and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square-shaped secondary battery.SOLUTION: In a square-shaped secondary battery, a flat-shaped electrode body includes a core-body exposed portion of a wound first electrode, the core-body exposed portion of the wound first electrode includes a small thickness part where core-body exposed portions are bundled, a first part located closer to a sealing plate side than the small thickness part and having a thickness larger than that of the small thickness part, and a second part located closer to a bottom side than the small thickness part and having a thickness larger than that of the small thickness part, a current-collecting member is resistance welded to the core-body exposed portion of a wound first electrode, the current-collecting member includes a plate-like first region disposed on the outer most surface side of the small thickness part and a second region extending from an end part of the sealing plate side of the first region toward the sealing plate side than an end part of the sealing plate in the flat shaped-electrode body, and an insulation film is disposed between the second region and the outer most surface of the core-body exposed portion of a wound first electrode.

Description

  The present invention relates to a prismatic secondary battery and a manufacturing method thereof, and more particularly to a current collector structure of a prismatic secondary battery and a manufacturing method thereof.

  In recent years, an electric vehicle using a secondary battery as a drive power source such as a hybrid vehicle is becoming widespread. However, an electric vehicle requires a high output secondary battery. In addition, with higher functionality for mobile electronic devices such as mobile phones and notebook computers, higher output is also required for these applications.

  In order to increase the output of the battery, it is necessary to increase the facing area of the positive and negative electrodes. High power output of the battery can be achieved by having a laminated electrode body structure in which a large number of positive and negative electrode plates are laminated or a spiral electrode body structure in which a long positive and negative electrode plate is wound through a separator, so that the opposing area of the positive and negative electrodes can be increased. It is easy to plan.

  In high-power batteries using laminated electrode bodies and spiral electrode bodies, a structure in which a current collector plate is welded to the exposed part of the positive and negative cores and the current collector plate is connected to an external output terminal in order to take out current stably. Is adopted. Moreover, since a large current can be taken out more stably as the number of connection points between the current collector plate and the positive and negative cores is increased, the number of welding points is set to two or more (see Patent Document 1).

  However, if there are a plurality of welding locations in resistance welding, as shown in FIG. 24, the current spreads in the lateral direction of the current collector plate, and the current flows through the previously welded locations. Since this current becomes an ineffective current that is not useful for welding, it becomes difficult to pass a necessary current to a desired welding location. On the other hand, if the voltage is increased in order to allow a sufficient current to flow through the welding location, there is a problem that spatter is generated and thus high-quality welding cannot be performed and electric energy is wasted.

  In Patent Documents 2 and 3, the current collector plate is divided into a plurality of members on the same surface of the edge of the core in the surface direction, and a pair of welding electrodes are brought into contact with each current collector plate. A technique for flowing a welding current has been proposed. However, in the techniques described in Patent Documents 2 and 3 below, since the edge of the core body and the current collector plate are welded, it is difficult to increase the welding area and it is difficult to sufficiently improve the current collection efficiency. Moreover, since the strength of the edge of the core is weak, it is difficult to obtain sufficient welding strength. Furthermore, since it is necessary to use a special technique for welding, there is a problem that the productivity of the battery is reduced accordingly.

JP 2006-12830 A JP 2002-164035 A JP 2002-184451 A

1st invention for solving the said subject has the core exposed part of the 1st electrode laminated | stacked on one edge part, and a polarity differs from the said 1st electrode laminated | stacked on the other edge part. An external output terminal having a flat electrode body having a core exposed portion of the second electrode and a rectangular battery case that accommodates the flat electrode body, and further connected to at least the first electrode so as to be energized. In a method for producing a rectangular secondary battery for producing a rectangular secondary battery having:
A current collecting first member is disposed on a first welding scheduled portion set on the outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion of the core exposed portion of the stacked first electrode. A step of resistance welding the current collecting first member and the core exposed portion in the stacking direction of the core exposed portion of the first electrode;
The outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion is set at a position that is separated from the first welding scheduled portion and is not in contact with the current collecting first member. A step of arranging a current collecting second member on the two welding scheduled portions and resistance welding the current collecting second member and the core exposed portion in the stacking direction of the core exposed portion of the first electrode;
After the two steps are completed, the step of connecting the current collecting first member and the current collecting second member so that energization is possible in a route different from the route through the core exposed portion of the first electrode; It is characterized by providing.

  In this configuration, before connecting the current collector first member and the current collector second member so as to be energized, the current collector first member and the core body exposed portion, and the current collector second member and the core body exposed portion are respectively connected to each other. Separate resistance welding. Therefore, the current flowing in the lateral direction during resistance welding (reactive current that does not contribute to welding) can be reduced, and as a result, high-quality electric resistance welding can be performed with less current.

  In this configuration, the current collecting first member or the current collecting first is performed before any of the above steps, or after the step of connecting the current collecting first member and the current collecting second member so as to be energized. The two members and the external output terminal are connected so as to be energized. Thereby, the electricity of the first electrode can be taken out to the outside.

2nd invention has the core exposure part of the 1st electrode laminated | stacked on one edge part, and the core exposure of the 2nd electrode from which polarity differs from the said 1st electrode laminated | stacked on the other edge part A flat electrode body having a portion;
A prismatic battery case that houses a rectangular battery case that houses the flat electrode body, and further includes an external output terminal that is connected to at least the first electrode so as to be energized. ,
A current collecting first member is disposed on a first welding scheduled portion set on the outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion of the core exposed portion of the stacked first electrode. The 1-1 step of resistance welding the current collecting first member and the core exposed portion in the stacking direction of the core exposed portion of the first electrode;
The outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion is set at a position that is separated from the first welding scheduled portion and is not in contact with the current collecting first member. (2) 1-2 step of arranging a current collecting second member in a planned welding portion and resistance welding the current collecting second member and the core exposed portion in the stacking direction of the core exposed portion of the first electrode; ,
After the 1-1 step and the 1-2 step are completed, a 1-3 step of arranging and welding a conductive connecting member that connects both members to the first current collecting member and the second current collecting member. When,
Before any one of the steps 1-1 to 1-3, or after the step 1-3, the current collecting first member, the current collecting second member, or the conductive connecting member 1-4 process which connects an external output terminal so that electricity supply is possible, It is characterized by the above-mentioned.

  In this configuration, the member that collects current from the first electrode is divided into three parts: a current collecting first member, a current collecting second member, and a conductive connecting member, and the current collecting first member and the current collecting second member; Are placed in positions where they are not in direct contact, and each is resistance welded to the core exposed portion, and then a conductive connecting member is welded to both members, and the two members are connected by the conductive connecting member. With this configuration, when the current collecting first member and the current collecting second member are resistance-welded to the electrode core exposed portion, it is possible to reduce generation of reactive current (current that does not contribute to welding) flowing in the lateral direction. Good quality welding can be done with low current.

In the above configuration, any one of the current collecting first member, the current collecting second member, and the conductive connecting member is connected to the external output terminal so as to be energized in step 1-4. In a rectangular secondary battery using a flat electrode body, the quality of current collection depends on the welding contact state between the core exposed portion and the current collector plate, but the current collection depends on the connection path to the external output terminal. Since stability and current collection efficiency are not harmed, if the current collector member is properly resistance-welded to the core exposed part in steps 1-1 to 1-3, the external output terminal can be connected via any member. Even if it is connected to, the current collection efficiency does not decrease. Therefore, the above 1-4 step may be either before any of the 1-1 steps to 1-3 steps or after the 1-3 steps.

  From the above, according to the above configuration, a rectangular secondary battery excellent in current collection stability and current collection efficiency can be manufactured with high productivity.

  Here, as a typical example of the above flat electrode body, there is a flat electrode body that is formed by crushing a belt-shaped positive and negative electrode plate wound into a flat shape. It also includes a stacked electrode body in which a plurality of electrode plates are stacked via a separator. The “flat portion of the end portion of the electrode body from which the core exposed portion of the first electrode protrudes” refers to a portion of the flat portion of the flat electrode body that protrudes with the core exposed portion overlapping. . In addition, in the case where the wound electrode is crushed into a flat shape, both end portions in the rotation direction are semi-elliptical, and an intermediate portion between both end portions is flat. In addition, the current collection system formed by the three members of the current collecting first member, the current collecting second member, and the conductive connecting member in this configuration corresponds to a conventional current collector.

According to a third aspect of the present invention, in the method for manufacturing a prismatic secondary battery according to the second aspect of the invention, the core exposed portion of the stacked first electrode is replaced with the step 1-4 from the step 1-1. The current collecting first member is disposed on the first welding scheduled portion set on the outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion, and the first receiver is disposed on the opposing surface of the flat portion. 2-1 step of resistance welding the current collecting first member, the core body exposed portion, and the first receiving member in a state where the members are disposed and the core body exposed portion is sandwiched between both members;
The outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion is set at a position that is separated from the first welding scheduled portion and is not in contact with the current collecting first member. (2) A second current collecting member is disposed on the planned welding portion, a second receiving member is disposed on the opposing surface of the flat portion, and the second current collecting member is sandwiched between the two exposed members and the core exposed portion. 2-2 process of resistance welding the member, the core exposed portion and the second receiving member;
After the 2-1 step and the 2-2 step are finished, between the current collecting first member and the current collecting second member, or between the first receiving member and the second receiving member. And 2-3 step of placing the conductive connecting member and welding the conductive connecting member and the respective members facing the conductive connecting member,
Before any one of the steps 2-1 to 2-3, or after the 2-3 step, the current collecting first member, the current collecting second member, the first receiving member, the second 2-4 process of connecting any one of said receiving member or said electroconductive connection member, and said external output terminal so that electricity supply is possible.

  According to the above-described configuration in which the receiving member is disposed on the opposite side of each of the current collecting first member and the current collecting second member, and resistance welding is performed with the upper and lower surfaces of the core body exposed portion sandwiched, the strength of the welded portion increases. , Current collection efficiency is improved. Further, when receiving parts for the current collecting first member and the current collecting second member (hereinafter, these may be abbreviated as current collecting members) are not arranged, the tip of one electrode rod is exposed as a core during welding. The welded part may stick to the melted part of the part and damage the welded part when the electrode rod is removed, but this does not occur in the above configuration.

  Note that the above 2-4 step does not mean the last step. Therefore, as in the step 1-4, the step 2-4 may be performed before any of the steps 2-1 to 2-3, or after the step 2-3.

According to a fourth aspect of the present invention, in the method for manufacturing a prismatic secondary battery according to the second aspect of the invention, the stacking direction of the core exposed portion of the first electrode in the flat portion of the core exposed portion of the stacked first electrode. The first current collecting member is disposed on the first welding scheduled portion set on the outermost surface of the first portion, the first receiving member is disposed on the opposing surface of the flat portion, and the core exposed portion is sandwiched between the first receiving member and the first exposed member. 3-1 step of resistance welding the current collector first member, the core exposed portion and the first receiving member;
The current collecting second member is a connected current collecting second member having an extension, and is the outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion, and from the first welding planned portion A main body portion of the connected current collecting second member is disposed in a second welding scheduled portion set at a position that is spaced apart and does not contact the current collecting first member and the members, and the connected current collecting second The extension part of the member is arranged in a non-contact manner with the first current collecting member, and the second receiving member is arranged on the opposing surface of the flat part where the main body part is located, and then the core body exposed part is sandwiched. 3-2 step of resistance welding the main body part of the connected type current collecting second member, the core exposed part and the second receiving member in a state;
After the 3-1 step and the 3-2 step are finished, a 3-3 step of contacting and welding the extension part of the connected current collecting second member and the current collecting first member;
Before any one of the steps 3-1 to 3-3, or after the 3-3 step, the current collecting first member, the connected current collecting second member, the first receiving member, or And 3-4 step of connecting any one of the second receiving members and the external output terminal so that energization is possible.

  The “connected current collecting second member having an extension” in this configuration is an integrated structure of the current collecting second member and the conductive connecting member, and the extension of the connected current collecting second member is It is a portion corresponding to the conductive connecting member in the first invention, and the main body portion of the connected current collecting second member is a portion corresponding to the current collecting second member in the first invention. In this configuration, since the connected current collecting second member in which the current collecting second member and the conductive connecting member are integrated is used, it is possible to reduce the number of parts and the number of welding locations.

  Further, in this configuration, the first collector member and the first receiving member, and the second collector current collector 2 in a state where the extension portion of the second collector current collector member is disposed in a non-contact manner with the first collector member. The main body of the member and the second receiving member are resistance welded (step 3-1 and step 3-2), and then the non-contact portion is contact welded (step 3-3). With this manufacturing method, it is possible to reduce the generation of reactive current (current that does not contribute to welding) flowing in the lateral direction during resistance welding, so that high-quality resistance welding can be performed.

  Further, the step 3-4 may be performed before any of the steps 3-1 to 3-3 or after the step 3-3, as in the step 2-4.

  As described above, according to the above configuration, high-quality resistance welding can be performed while reducing the number of components and the number of welding locations. As a result, it is possible to produce a prismatic secondary battery excellent in current collection efficiency and current collection stability with high productivity. The current collection stability means that good current collection efficiency is maintained over a long period of time by strong welding.

  Here, the “non-contact arrangement” refers to a state where they are arranged close to each other so that they can be easily brought into contact with each other but are not yet in contact (a state where they cannot conduct electricity). In 3rd invention structure, it means that both members do not contact directly and the extension part of a connection type | mold current collection 2nd member is located above the edge part of a current collection 1st member.

  A typical example of the “non-contact arrangement” is an arrangement in which a slight gap is interposed between the lower surface of the extended portion of the connected current collecting second member and the upper surface of the current collecting first member so as to prevent conduction. It is done. Moreover, it is good also to interpose the insulating film piece which can be removed with a fusion | melting heat to the opposing surface between both members as a spacer.

According to a fifth aspect of the present invention, in the method for manufacturing a prismatic secondary battery according to the second aspect of the present invention, the stacking direction of the core exposed portion of the first electrode in the flat portion of the core exposed portion of the stacked first electrode. The current collecting first member is arranged on the first welding scheduled portion set on one side of the outermost surface, and the first receiving member is arranged on the opposing surface of the flat portion, and the core body is exposed by both members. 4-1 step of resistance welding the current collecting first member, the core exposed portion, and the first receiving member in a state where the portion is sandwiched, and the current collecting second member having an extension portion. When the flat portion is seen through from the stacking direction of the core exposed portion of the first electrode, the first current collecting member and the main body of the connected current collecting second member overlap each other. A main body portion of the connected current collecting second member is arranged at a position on the facing surface side that should not be, and the connected current collecting second member After the extension portion is disposed in a non-contact manner on the first receiving member, and the second receiving member is disposed on the one surface, the core body exposed portion is sandwiched between the main body portion and the second receiving member. 4-2 step of resistance welding the main body part, the core exposed part and the second receiving member in a state;
After the 4-1 step and the 4-2 step are finished, a step 4-3 for contacting and welding the extension portion of the second connecting current collecting member and the first receiving member;
Before any one of the steps 4-1 to 4-3, or after the step 4-3, the first current collecting member, the second connected current collecting member, the first receiving member, or And 4-4 step of connecting any one of the second receiving members and the external output terminal so that energization is possible.

  In this configuration, the current collecting first member is disposed on one surface of the core exposed portion, and the connected current collecting second member is disposed on the other surface (a surface facing the one surface). In this configuration, the current collecting first member and the second receiving member are arranged on one side of the core body exposed portion, and the first receiving member and the connected current collecting second member are arranged on the other side. Therefore, the extension portion of the connected current collecting second member is connected to the first receiving member. Also in this configuration, the same effect as that of the third invention can be obtained. In this configuration, the portion to be welded between the main body portion of the connection-type current collecting second member and the second receiving member is the second melt planned portion.

  Further, the step 4-4 may be performed before any of the steps 4-1 to 4-3 or after the step 4-3 as in the step 2-4.

According to a sixth aspect of the present invention, in the method for manufacturing a prismatic secondary battery according to the second aspect of the invention, the current collector first member is a connected current collector first member having an extension, and the stacked first electrodes A main body portion of the connected current collecting first member is disposed on the first welding scheduled portion set on the outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion of the core exposed portion of The first receiving member is disposed on the opposite surface of the flat portion, and the main body portion of the connected current collector first member, the core body exposed portion, and the first body are sandwiched between the core body exposed portions. 5-1 step of resistance welding the receiving member;
The current collecting second member is a connected current collecting second member having an extension portion, and the stacked portion of the core exposed portion of the first electrode in the flat portion of the core exposed portion of the stacked first electrode is arranged. A main body portion of the connected current collecting second member is disposed on the second welding scheduled portion set on the outermost surface, a second receiving member is disposed on the opposing surface of the flat portion, and the connected current collecting portion is disposed. The extension part of the first current collecting member and the extension part of the second connecting current collecting member are superimposed in a non-contact manner, and then the second connecting member main body part and the second receiving member 5-2 step of resistance-welding the main body part of the connection-type current collector second member, the core body exposed part, and the second receiving member with the core body exposed part sandwiched therebetween,
After the step 5-1 and the step 5-2, the overlapping part of the extension part of the connection type current collector first member and the extension part of the connection type current collector second member are contacted and welded 5-3. Process,
Before any one of the steps 5-1 to 5-3, or after the step 5-3, the connected current collecting first member, the connected current collecting second member, the first receiving member, Or 5-4 step of connecting any one of the second receiving members and the external output terminal so as to be energized.

Also in this configuration, the above step 5-4 is the same as the above step 2-4, from step 5-1 to
It may be either before any step of the 5-3 step or after the 5-3 step.

  Also in this configuration, similar to the third and fourth inventions, high-quality resistance welding can be performed while reducing the number of parts and the number of welded portions, so that it can withstand a large output discharge. A square secondary battery excellent in current collection efficiency and current collection stability can be manufactured with high productivity.

7th invention has the core exposure part of the 1st electrode laminated | stacked on one edge part, and the core exposure of the 2nd electrode from which polarity differs from the said 1st electrode laminated | stacked on the other edge part A flat electrode body having a portion;
A rectangular battery case that houses the flat electrode body, and a sealing plate that seals the rectangular battery case;
An external output terminal that is inserted into a through hole provided in the sealing plate and protrudes outward from the battery from the inside of the battery, and the external output terminal and the first electrode are connected to be energized. In the secondary battery manufacturing method,
6-1 step of inserting the external output terminal into the through hole of the sealing plate and connecting the external output terminal and the current collecting first member so as to allow energization;
The current collecting first member is disposed on a first welding scheduled portion set on the outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion of the core exposed portion of the stacked first electrode. And 6-2 step of resistance welding the current collecting first member and the core exposed portion in the stacking direction of the core exposed portion of the first electrode,
The outermost surface in the stacking direction of the core exposed portion of the first electrode in the flat portion is set at a position that is separated from the first welding scheduled portion and is not in contact with the current collecting first member. 2-6-3 process which arrange | positions a current collection 2nd member in 2 welding scheduled parts, and resistance-welds the said 2nd current collection member and the said core body exposed part in the lamination direction of the core body exposed part of the said 1st electrode. When,
After the steps 6-1 to 6-3 are completed, the current collecting first member and the current collecting second member can be energized through a route different from the route through the core exposed portion of the first electrode. 6-6 processes to connect.

  In this configuration, the current collecting first member is first connected to the external output terminal, and then the current collecting first member is resistance-welded to the flat portion of the end portion of the electrode body from which the core exposed portion of the first electrode protrudes. With this procedure, workability in battery assembly is good. Here, the connection between the external output terminal and the current collecting first member may be directly connected to each other, or may be made via another conductive member. In addition, a current interruption mechanism can be interposed between the external output terminal and the current collecting first member.

  The eighth invention is the method of manufacturing a prismatic secondary battery according to the seventh invention, wherein the current collector second member is a connected current collector second member having an extension, and the step 6-4 Is a step of resistance-welding the extension of the current collector second member to the upper surface of the current collector first member to connect the current collector first member and the current collector second member so as to be energized, Of the surface on the resistance welding side of each member, at least a portion that contacts the first welding scheduled portion of the current collecting first member and a portion that contacts the second welding planned portion of the current collecting second member, In addition, an insulating film is provided on the surface on the resistance welding side of each member excluding each part of the extension part of the current collecting second member that is resistance welded to the current collecting first member, prior to resistance welding. And

  In this configuration, electrical resistance welding is performed after an insulating film is provided on the peripheral portion (non-welding scheduled portion) excluding the planned welding portion of the current collecting first member and the connected current collecting second member. With this configuration, it is possible to prevent unnecessary members from coming into contact with each other during the welding operation and to prevent a wasteful current from flowing, so that high-quality resistance welding can be performed with good workability.

  According to a ninth aspect of the present invention, in the method for manufacturing a prismatic secondary battery according to any one of the first to eighth aspects, a core body having the same polarity is provided between the first welding planned portion and the second welding planned portion. It is characterized by providing a core notch formed by notching the laminated core exposed portion where the exposed portions are stacked.

  When the core cutout portion is set between the first weld planned portion and the second weld planned portion, the electrode rod for resistance welding or the super A welding tool such as an anvil and a horn used in sonic welding can be inserted up to the bottom surface (lower surface of the core exposed portion) of the constituent member. Thereby, welding workability improves markedly. Therefore, according to this configuration, it is possible to further increase the productivity of the rectangular secondary battery having a current collection efficiency that can withstand a large output.

  According to a tenth aspect of the present invention, in the method for manufacturing a rectangular secondary battery according to any one of the first to ninth aspects, the current collecting first member, the connected current collecting first member, or the current collecting second member. Alternatively, the connected current collecting second member, the first receiving member, and the second receiving member are made of aluminum or an aluminum alloy.

  Aluminum and aluminum alloys are materials having good electrical conductivity and thermal conductivity. Therefore, it is necessary to flow a large current at the time of resistance welding. For this reason, reactive current (current that does not contribute to welding) is likely to occur. However, according to the manufacturing method of the present invention, reactive current can be greatly suppressed. In the case of using a member made of a material, the effects of the present invention are particularly remarkably exhibited.

  The method for manufacturing a rectangular secondary battery according to the present invention can efficiently perform high-quality welding with less current in resistance welding work in which a current collecting member is attached to an electrode core exposed portion. Therefore, according to the present invention, a prismatic secondary battery that can cope with a large output discharge and has excellent current collection efficiency and current collection stability can be manufactured with high productivity.

FIG. 1 is a perspective view showing an external appearance of the prismatic secondary battery according to the first embodiment. FIG. 2 is a schematic front view of the positive and negative electrode plates according to the first embodiment. FIG. 3 is a schematic front view of a flat electrode body to which each member of the current collecting system according to the first embodiment is attached. FIG. 4 is a schematic cross-sectional view illustrating a procedure for attaching each current collecting system member according to the first embodiment to the core body exposed portion. FIG. 5 is a schematic cross-sectional view of a flat electrode body according to the second embodiment that does not use a receiving member. FIG. 6 is a schematic front view of a flat electrode body according to the third embodiment. FIG. 7: is a cross-sectional schematic diagram for demonstrating the manufacturing procedure which attaches each current collection system member concerning Embodiment 3, FIG. 7 (a) is a figure which shows a connection type | mold current collection 2nd member, FIG. FIG. 7B is a diagram showing resistance welding work in the first welding scheduled portion and the second welding scheduled portion, and FIG. 7C is a diagram showing indirect resistance welding work in the welding planned portion 103. FIG. 8A is a schematic front view of an electrode core body having a cutout according to the fourth embodiment, and FIG. 8B is a schematic side view of a flat electrode body having a core cutout portion. . FIG. 9 is a schematic front view of a flat electrode body according to the fourth embodiment to which each current collecting system member is attached. FIG. 10 is a schematic cross-sectional view for explaining a manufacturing procedure for attaching each current collecting system member according to the fourth embodiment to a flat electrode body. FIG. 11 is a schematic cross-sectional view illustrating a manufacturing procedure for attaching each current collecting system member according to the fifth embodiment to a flat electrode body, and FIG. 11 (a) is a diagram showing a connected current collecting first member; FIG. 11B is a diagram showing resistance welding work in the first welding scheduled portion and the second welding scheduled portion, and FIG. 11C is a diagram showing resistance welding work in the scheduled welding portion 103. FIG. 12A is a schematic front view of a flat electrode body according to the sixth embodiment, and FIG. 12B is a schematic cross-sectional view showing a state of laser welding for attaching each current collecting system member. FIG. 13 is a schematic cross-sectional view of a flat electrode body to which members of the current collecting system according to the seventh embodiment are attached. FIG. 14 is a schematic cross-sectional view showing another aspect of the seventh embodiment. FIG. 15 is a perspective view illustrating the shape of the positive electrode current collector first member according to the eighth embodiment. FIG. 16 is a schematic cross-sectional view showing a sealing body portion in which an external output terminal and a current collecting first member are attached to a sealing plate. FIG. 17 is a view showing a state in which the current collecting first member according to the eighth embodiment is resistance-welded to the laminated core body exposed portion. FIG. 18 is a diagram illustrating a state in which the connection-type current collecting second member according to the eighth embodiment is resistance-welded to the laminated core body exposed portion. FIG. 19 is a diagram illustrating a state in which resistance-welding is performed between the first current collecting member and the connected current collecting second member according to the eighth embodiment. FIG. 20 is a schematic cross-sectional view of the battery according to the eighth embodiment. FIG. 21A is a schematic front view of a flat electrode body to which a current collector is attached according to Reference Example 1, and FIG. 21B is a schematic cross-sectional view thereof. FIG. 22 is a schematic front view of a flat electrode body to which a current collector according to Reference Example 2 in which slits are formed is attached. FIG. 23 is a schematic front view of a flat electrode body to which a current collector according to Reference Example 3 in which a hole is formed is attached. FIG. 24 is a diagram for explaining the reason why a reactive current is generated when resistance-welding a conventional current collector plate.

(Embodiment 1)
The case where the manufacturing method of the present invention is applied to a prismatic lithium ion secondary battery will be described with reference to the drawings. FIG. 1 is a perspective view showing an external appearance of a prismatic lithium ion secondary battery according to the first embodiment. FIG. 2 is a schematic diagram of positive and negative electrode plates used in the prismatic lithium ion secondary battery according to the first embodiment. FIG.

  As shown in FIG. 1, a rectangular lithium ion secondary battery according to Embodiment 1 includes a rectangular battery case 1, a sealing body including a sealing plate 2 that seals the opening of the battery case 1, and a sealing body. A positive external output terminal 5 and a negative external output terminal 6 projecting outward are provided.

  The positive electrode plate 11 and the negative electrode plate 12 are wound and pressed through a separator made of a resin-made microporous film such as polyethylene, and the flat electrode body 10 is manufactured. Positive and negative electrode cores protrude from both end faces of the electrode body 10.

  The end face on the positive electrode side will be described in detail. As shown in FIG. 3, the positive electrode current collector first member 13 is welded to the first welding scheduled portion 101 set at the flat portion of the positive electrode laminated core exposed portion 11 c protruding from the end face of the flat electrode body 10. The positive electrode current collector second member 14 is welded to the second welding planned portion 102 set at a position away from the first welding planned portion 101. Moreover, as shown in FIG. 4, both members are spaced apart so that the opposite ends of the positive electrode current collector first member 13 and the positive electrode current collector second member 14 do not come into contact with each other.

In addition, a positive electrode conductive connecting member 15 is disposed at a separation portion of both the positive electrode current collecting first member 13 and the positive electrode current collecting second member 14 so as to straddle the separating portion. The positive electrode current collector first member 13 and the positive electrode current collector second member 14 are welded at welding points 103 and 103, respectively. Thereby, each member of the positive electrode laminated core exposed part 11c, the positive electrode current collector first member 13, the positive electrode current collector second member 14, and the positive electrode conductive connecting member 15 is connected and coupled so as to be energized.
Further, the extended portion of the positive current collector first member 13 is connected to the positive external output terminal directly or via a lead wire. Hereinafter, such a current collecting structure is referred to as a current collecting system structure, and each member used in this structure is referred to as a current collecting system member.

  Moreover, the said 1st welding scheduled part 101 and the 2nd welding scheduled part 102 become the 1st welding part 101 and the 2nd welding part 102 after completion | finish of welding. In the first embodiment, the same current collecting system structure is adopted for the negative electrode side. However, since the structure of the negative electrode side is the same as that of the positive electrode side, description thereof is omitted.

  In Embodiment 1, aluminum is used for each member of the positive electrode core body, the positive electrode current collector first member, the positive electrode current collector second member, and the positive electrode conductive connecting member. Copper is used.

  The electrode body 10 to which each member of the current collecting system is welded is housed in the battery case 1 together with the non-aqueous electrolyte, and the positive electrode current collecting first member 13 and the negative electrode current collecting first member 16 have respective positive and negative external output terminals. 5 and 6 are connected to be energized (not shown). In addition, the connection to the external output terminal can be performed by further interposing a lead wire in the extended portion of the positive and negative current collecting first member 13.

  As shown in FIG. 2, both positive and negative electrode plates have positive and negative active material layers 11a and 12a formed on a foil-shaped core, and positive and negative core exposed portions 11b and 12b formed at one end along the longitudinal direction. Has been. After stacking such positive and negative electrode plates through a separator so that the positive electrode core exposed portion 11b protrudes from one end of the spiral electrode body and the negative electrode core exposed portion 12b protrudes from the other end. Wrap it. Thereafter, pressing is performed to produce a flat electrode body. The protruding positive and negative electrode core exposed portions 11b and 12b become the laminated core exposed portions 11c and 12c. In addition, although it is also possible to form a core body exposure part in both the edge parts along a longitudinal direction, if it does in this way, a weight energy density will fall.

  Details of a method for manufacturing the prismatic lithium ion secondary battery having the above structure will be described.

<Preparation of positive electrode plate>
A ratio of 90: 5: 5 in a mass ratio of a positive electrode active material made of lithium cobalt oxide (LiCoO ₂ ), a carbon-based conductive agent such as acetylene black or graphite, and a binder made of polyvinylidene fluoride (PVDF). The sample was dissolved in an organic solvent composed of N-methyl-2-pyrrolidone and then mixed to prepare a positive electrode active material slurry.

  Next, using a die coater or a doctor blade, this positive electrode active material slurry was applied to both surfaces of a positive electrode core made of a strip-shaped aluminum foil (thickness: 20 μm) with a uniform thickness. However, the slurry was not applied to one end portion along the longitudinal direction of the positive electrode core body (end portions in the same direction on both surfaces), and the core body was exposed to form the positive electrode core exposed portion 11b.

  The electrode plate was passed through a dryer to remove the organic solvent, and a dried electrode plate was produced. This dry electrode plate was rolled using a roll press so that the thickness thereof was 0.06 mm to produce a positive electrode plate. The positive electrode plate thus produced was cut into a strip shape having a width of 100 mm to obtain a positive electrode plate 11 provided with a positive electrode core exposed portion 11b made of strip-shaped aluminum having a width of 10 mm (FIG. 2 (a)). .

In addition to the lithium cobaltate, the positive electrode active material includes, for example, lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), lithium ferrate (LiFeO ₂ ), or oxides thereof. A lithium-containing transition metal composite oxide such as an oxide obtained by substituting a part of the transition metal with another element can be used alone or in admixture of two or more.

<Preparation of negative electrode plate>
A negative electrode active material made of artificial graphite having a volume average particle diameter of 20 μm, a binder made of styrene butadiene rubber, and a thickener made of carboxymethyl cellulose were weighed in a mass ratio of 98: 1: 1, and these were measured. A negative electrode active material slurry was prepared by mixing with an appropriate amount of water.

  Next, using a die coater or a doctor blade, the negative electrode active material slurry was applied to both surfaces of a negative electrode core made of a strip-shaped copper foil (thickness: 12 μm) with a uniform thickness. However, the slurry was not applied to one end along the longitudinal direction of the negative electrode core (ends in the same direction on both surfaces), and the core was exposed to form the negative electrode core exposed portion 12b.

  The electrode plate was passed through a dryer to remove moisture, and a dried electrode plate was produced. Then, this dry electrode plate was rolled by a roll press machine so that the thickness became 0.05 mm, and the negative electrode plate was produced. The negative electrode plate thus produced was cut into a strip shape having a width of 110 mm to obtain a negative electrode plate 12 provided with a strip-shaped negative electrode core exposed portion 12b having a width of 8 mm (FIG. 2 (b)).

  In addition, as the negative electrode active material, carbonaceous materials such as natural graphite, carbon black, coke, glassy carbon, carbon fiber, or a fired body thereof instead of or in addition to the above artificial graphite, or the carbonaceous material and lithium , Lithium alloys, and mixtures with one or more selected from the group consisting of metal oxides capable of occluding and releasing lithium can be used.

<Production of electrode body>
In the positive electrode plate, the negative electrode plate, and a separator made of a resin microporous membrane (thickness: 0.022 mm), a plurality of homopolar core exposed portions directly overlap each other, and different core exposed portions are wound in the winding direction. In contrast, the three members are aligned and overlapped so that separators are interposed between different active material layers, wound with a winder, and then provided with an insulating winding tape. Later, it was pressed to complete a flat electrode body.

<Attachment of current collector components>
As shown in FIGS. 3 and 4 (a) to 4 (b), flat portions (flat portions) of the positive and negative laminated core exposed portions projecting from both ends in the direction orthogonal to the winding direction of the flat electrode body 10 are shown. Also, the current collecting system members are arranged. FIG. 3 is a schematic front view showing the flat electrode body after the current collecting system members are arranged by welding. FIG. 4 is a schematic cross-sectional view schematically showing a cross section perpendicular to the winding direction of the positive electrode core exposed portion. FIG. 4A shows a current collecting first member 13 and a first receiving member 19. And it is a figure which shows a mode that the laminated core body exposed part 11c is pinched | interposed by the current collection 2nd member 14 and the 2nd receiving member 20, and each is resistance-welded, FIG.4 (b) is after this resistance welding, FIG. 3 is a diagram showing a state where a current collecting first member 13 and a current collecting second member 14 are connected by a conductive connecting member 15.

  In this specification, the direction in which the electrode plate surface of the flat electrode body is viewed is the front surface (front view), the direction in which the side surface of the electrode body is viewed is the side surface, This is called a schematic diagram.

A specific method for attaching each member of the current collecting system will be further described taking the positive current collecting system structure as an example. First, an aluminum positive electrode current collector first member 13 (hereinafter abbreviated as “positive electrode”) is arranged on the central left side of the flat portion of the laminated core exposed portion 11c, and an aluminum first electrode 13 is described on the opposite surface. One receiving member 19 is arranged. The front ends of the electrode rods 104 and 104 are brought into contact with the current collecting first member 13 and the first receiving member 19 so that the front ends of the welding electrode rods face each other, and a current flows between both members. As a result, the current collecting first member 13, the laminated core body exposed portion 11 c, and the first receiving member 19 are resistance welded. This resistance welded portion is the first welded portion 101, and the portion before welding is referred to as a first welded portion 101.

  Subsequently, the current collecting second member 14 is arranged on the right side of the center of the laminated core exposed portion 11c so as not to contact the end of the current collecting first member 13, and the second receiving member is disposed on the opposite surface side. 20 is arranged. In the same manner as described above, the electrode rod tips 104 ′ and 104 ′ are brought into contact with each of the two members, and a current flows. Thereby, the current collection second member 13, the laminated core exposed portion 11c, and the second receiving member 20 are resistance-welded (see FIG. 4A). This resistance welded portion is the second welded portion 102, and the portion before welding is referred to as a second welded portion 102.

  Subsequently, the conductive connecting member 15 is disposed so as to straddle the separated portion of the current collecting first member 13 and the current collecting second member 14 fixed by the resistance welding method. And in the part which overlaps with the current collection 1st member 13, and the part which overlaps with the current collection 2nd member 14 (welding point 103 * 103), the electroconductive connection member 15, the current collection 1st member 13, and the current collection 2nd member 14 is laser welded (see FIG. 4B). In laser welding, it is preferable to irradiate the end of the conductive connecting member with laser. In addition, you may perform the welding of the said part using an ultrasonic welding method.

  The negative electrode side was also welded in the same manner as described above.

<Preparation of electrolyte>
LiPF ₆ as an electrolyte salt is added to a non-aqueous solvent in which ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) are mixed at a volume ratio of 1: 1: 8 (1 atm, 25 ° C.). A solution dissolved at a rate of 1.0 M (mol / liter) was used as an electrolytic solution.

In addition, the non-aqueous solvent of this embodiment which uses a lithium ion secondary battery as an example is not limited to the above combination. For example, a high dielectric constant solvent having a high solubility of lithium salts such as ethylene carbonate, propylene carbonate, butylene carbonate, and γ-butyrolactone, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, tetrahydrofuran, anisole, 1, Low viscosity solvent such as 4-dioxane, 4-methyl-2-pentanone, cyclohexanone, acetonitrile, propionitrile, dimethylformamide, sulfolane, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, ethyl propionate It can be mixed and used. Furthermore, the high dielectric constant solvent and the low viscosity solvent can be used as a mixed solvent of two or more. In addition to LiPF ₆ described above, for example, LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiClO ₄ or LiBF ₄ may be used alone or in combination of two or more as the electrolyte salt. Can be used.

<Battery assembly>
One end portion of the positive electrode current collector first member 13 of the flat electrode body is connected to the positive electrode external output terminal 5, and one end portion of the negative electrode current collector first member 16 is connected to the negative electrode external output terminal 6. And caulking with an insulating gasket (not shown). Next, the electrode group 10 combined with the sealing plate 2 is inserted into the battery case 1, the sealing plate 2 is fitted into the opening of the battery case 1, and the joint between the periphery of the sealing plate 2 and the battery case 1 is laser welded. And after inject | pouring a predetermined amount of said electrolyte solution from the electrolyte solution injection hole (not shown) set to the sealing board 2, this electrolyte solution injection hole is sealed. Thus, the prismatic lithium ion secondary battery according to the first embodiment was completed.

Here, it is necessary that at least one “first welding planned portion” (also the first welding portion) and “second welding planned portion” (also the second welding portion) exist, The welding between the electric first member and the laminated core body exposed portion and the welding between the current collecting second member and the laminated core body exposed portion are not limited to one place, and may be a plurality of places. The same applies to the other embodiments described below.

[Embodiment 2]
FIG. 5 shows a current collecting structure according to the second embodiment. The second embodiment is the same as the first embodiment except that the receiving members 19 and 20 that receive the current collecting first member and the current collecting second member are not used. In Embodiment 2, the current collector first member and the laminated core body exposed portion are resistance-welded by sandwiching the current collector first member and the laminated core body exposed portion 11c between the electrode rods and energizing, and the current collector second member and Similarly, the laminated core body exposed portion 11c is resistance-welded, and then a predetermined portion of the conductive connecting member 15 is laser-welded.

  The second embodiment is advantageous in that the number of parts can be reduced compared to the first embodiment in that the receiving members 19 and 20 are not used. However, since the resistance welding rod is directly brought into contact with the laminated core exposed portion 11c without using the receiving member, there is a demerit that the laminated core exposed portion 11c made of a thin film is easily damaged.

[Embodiment 3]
In the third embodiment, a connected current collecting second member 21 in which the current collecting second member 14 and the conductive connecting member 15 in the first embodiment are integrated is used. FIG. 6 shows a schematic front view of the current collecting structure according to the third embodiment, and FIG. 7A shows a side shape of the connected current collecting second member 21. As shown in FIG. 7A, the connected current collecting second member 21 has a body portion 21a corresponding to the current collecting second member and an extension portion 21b for connecting the current collecting first member. It is.

  A manufacturing procedure of the current collecting structure according to the third embodiment will be described with reference to FIGS. First, in the same manner as in the first embodiment, the laminated core body exposed portion 11c is sandwiched between the current collecting first member 13 and the first receiving member 19 that is the receiving member, and the three members are resistance welded. Thereafter, the end of the current collecting first member 13 and the main body 21a of the connected current collecting second member 21 are separated from each other, and the distal end side of the extension 21b of the connected current collecting second member 21 is the current collecting first. The connected current collecting second member main body portion 21 a is disposed on the core exposed portion so as to be positioned on the member 13. At this time, a slight gap is left between the two members so that the extended portion 21b of the connected current collecting second member does not contact the upper surface of the current collecting first member 13 (see FIG. 7B).

  For example, the height H from the bottom surface of the main body portion 21a of the connection-type current collector second member 21 to the lower surface of the extension portion 21b is determined by the thickness of the current collector first member 13 as a means for providing a slight gap between the two members. Is slightly higher. Also, a thin resin insulating film that can be scattered and removed by welding heat may be adhered to the lower surface of the extension portion 21b of the connected current collecting second member or the corresponding portion of the current collecting first member. .

  The second receiving member 20 is disposed on the opposite side of the main body 21 a of the connected current collecting second member 21, and the main body 21 a, the laminated core body exposed portion 11 c, and the second receiving member 20 are sandwiched between the electrode bars 104. Resistance welding (see FIG. 7B). Then, the extension part 21b of the connection type current collector second member 21 is pressed toward the laminated core body exposed part 11c, the lower surface of the extension part 21b is brought into contact with the upper surface of the current collector first member 13, and the extension part 21b The electrode rod 104 ′ is brought into contact with the upper surface, while the electrode rod 104 is brought into contact with the current collecting first member surface and in the vicinity of the electrode rod 104 ′. An electric current is passed between both electrode rods, and the lower surface of the extension part 21b of the connected current collecting second member 21 and the upper surface of the current collecting first member 13 are resistance-welded (indirect resistance welding).

  In addition, another welding method (for example, laser welding method) may be used for welding the lower surface of the extension portion 21b of the connection-type current collecting second member 21 and the upper surface of the current collecting first member 13. Other matters are the same as those in the first embodiment.

  Since Embodiment 3 does not require a conductive connecting member as a separate member, the number of members and the number of welded portions can be reduced as compared with Embodiment 1 above. Therefore, productivity is improved as compared with the first embodiment.

[Embodiment 4]
The current collecting system structure according to the fourth embodiment is shown in FIGS. FIG. 8A is a schematic front view showing a state in which a part of the core body exposed portion 11b is cut out, and FIG. 8B is a side view showing the core body notched portion 26 of the laminated core body exposed portion 11c. It is a schematic diagram. FIG. 9 is a schematic front view of a flat electrode body to which each member of the current collecting system is attached, and FIG. 10 is a schematic cross-sectional view showing a state of resistance welding.

  As shown in FIGS. 8 to 10, the fourth embodiment is characterized in that a core notch 26 is formed in one part of the flat portion of the laminated core exposed portion 11 c, and other member shapes are used. Is the same as that of the third embodiment, and the manufacturing method is different only in the welding method between the current collecting first member 13 and the extension portion 21b of the connecting type current collecting second member 21 overlapping therewith. This is the same as in the third embodiment.

  In addition, since the core notch part 26 is not what cut out the electrode core part (electrode main-body part) which has an active material, it does not produce the fall of power generation capacity.

  FIG. 10 shows a characteristic part in the method for manufacturing a prismatic secondary battery according to the fourth embodiment. In this embodiment, since the core cutout portion 26 is provided between the first welding planned portion 101 and the second welding planned portion 102, this portion is obstructed by the laminated core exposed portion 11c. The welding electrode rod 104 ′ can be inserted to the opposite side without any problem. A welding operation using the core notch 26 is performed as follows.

  First, the current collector first member 13 is disposed on the surface of the laminated core body exposed portion 11c so that the end of the current collector first member 13 is positioned on the core body notch 26, and the opposite side of the laminated core body is exposed. The first receiving member is disposed at a position where the core cutout portion 26 on the surface is not blocked. In this state, the first welding scheduled portion 101 is resistance welded.

  Next, the main body portion 21 a of the connected current collecting second member 21 does not block the core cutout portion 26, and the extended portion 21 b overlaps the end portion of the current collecting first member 13. Two members 21 are arranged. In this arrangement, the main body portion 21 a of the connected current collecting second member 21 is in contact with the surface of the laminated core body exposed portion 11 c, and the extension portion 21 b is not in contact with the current collecting first member 13. Next, the second receiving member 20 is disposed on the surface of the laminated core body exposed portion 11c on the side opposite to the main body portion 21a of the connected current collecting second member 21. Thereafter, the main body portion 21a, the laminated core body exposed portion 11c, and the second receiving member 20 of the connected current collecting second member 21 are resistance-welded. About the method of resistance welding, it is the same as that of the said Embodiment 3. FIG.

  Next, by pressing the extension portion 21b of the connected current collecting second member 21 from above, the lower surface of the extension portion 21b and the upper surface of the current collecting first member end are brought into contact with each other, and the electrode rod is placed on the upper surface of the extension portion 21b. The electrode rod 104 ′ is brought into contact with the lower surface of the end portion of the current collecting first member from below and an electric current flows between the electrode rods. Thereby, the extension part 21b of the connection type | mold current collection 2nd member 21 and the current collection 1st member edge part are resistance-welded. In addition, the electrode rod 104 ′ comes into contact with the lower surface of the current collector first member end portion through the core cutout portion 26.

  In the fourth embodiment, since the connected current collecting second member 21 is used, the number of members and the welding location can be reduced, and by providing the core cutout portion 26, the current collecting first member 13 and the connected type are provided. Since the current collecting second member 21 can be sandwiched from above and below and resistance welding can be performed, workability is good and high quality welding can be performed.

[Embodiment 5]
FIG. 11 shows a current collecting system structure according to the fifth embodiment. In the fifth embodiment, as shown in FIGS. 11A to 11C, a connected current collector 1 having an extended portion 24b for connecting members to each other and a connected current collector having an extended portion 22b. The second member 22 is used.

  In the fifth embodiment, the extension portions of the connected current collector first member 24 and the connected current collector second member 22 are overlapped on the core cutout portion 26, and the portions are resistance welded. Although different from the fourth embodiment, the other points are the same as those of the fourth embodiment. Also in this embodiment, the same effect as that of the fourth embodiment can be obtained.

  In the fourth and fifth embodiments, the connected current collecting second member having an extended portion or the connected current collecting first member having an extended portion with respect to the laminated core exposed portion having the core notch portion. Although the connection type current collection 2nd member which has an extension part was used, the connection type member which has these extension parts can also be used with respect to the lamination | stacking core body exposure part which does not form a core notch part.

  In the fourth and fifth embodiments, the welding point 103 may be welded by using a laser welding method or an ultrasonic welding method instead of the resistance welding method. Even when a laser welding method or an ultrasonic welding method is used, welding workability can be improved by utilizing the core notch 26.

[Embodiment 6]
FIG. 12 shows a current collecting system structure according to the sixth embodiment. FIG. 12A is a schematic front view of the flat electrode body 10 on which a current collecting system member is arranged, and FIG. 12B is a schematic cross-sectional view showing a welding state. In the sixth embodiment, a connected current collector second member 25 having an L-shaped connected current collecting first member 25 having one end portion having a shelf portion, and an extended portion having a shape opposite to the L-shaped shelf portion. A member 23 is used.

  In this embodiment, as described in the third embodiment, when the welding scheduled portions 101 and 102 of the connected current collecting first member 25 and the connected current collecting second member 23 are resistance-welded, respectively. For example, an insulating film is provided on the lower surface of the shelf portion of the connected current collecting first member 25 and / or the extended portion of the connected current collecting second member 23 which is opposed to the shelf portion. The surfaces are not in contact with each other so that reactive current does not flow between the two members. Then, after the resistance welding operation in the first welding scheduled portion 101 and the second welding scheduled portion 102 is completed, the laser beam 105 is irradiated to the boundary between both members to weld the welding planned portion 103. Other matters are the same as in the third embodiment.

  In this embodiment, since the ends of the connected current collecting first member 25 and the connected current collecting second member face each other on the L surface, the contact state is stable and the contact area is large. Therefore, there is an advantage that electric resistance can be reduced. In addition, the welding of the welding point 103 can also use the ultrasonic welding method using an ultrasonic wave instead of a laser beam.

[Embodiment 7]
FIG. 13 shows a current collecting system structure according to the seventh embodiment. The seventh embodiment is different from the first embodiment in that the current collecting first member 13 having no extension portion is used and the conductive connecting member 15 having the extension portion 15a is used. In this embodiment, the conductive connecting member 15 having the extended portion 15a on the upper surface of both the current collecting first member 13 and the current collecting second member 14 is laser-welded, and the extended portion 15a of the conductive connecting member 15 is provided. And is connected to the positive external output terminal 5 so as to be energized. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

Here, current collecting members such as the first current collecting member and the second current collecting member are used to reduce electrical resistance.
It is better that the contact area with the core exposed portion is large. On the other hand, since the receiving member is a member whose main purpose is to increase the strength of the welded portion, it may have a smaller area than the current collecting member. However, even when there is no particular difference in the shape as shown in FIG. 13, for the sake of convenience for specifying the member, in this specification, one is referred to as a current collecting member and the other is referred to as a receiving member. .

  13 shows the structure in which the receiving member is arranged on the current collecting member side, but as shown in FIG. 14, the conductive connecting member 15 may be arranged on the receiving member side. In the third, third, fourth, fifth, and sixth embodiments, a configuration in which the external output terminal is connected via a member other than the current collecting first member may be employed.

[Embodiment 8]
In the eighth embodiment, after first combining the external output terminal, the sealing plate, and the first current collecting member, the current collecting first member and the connected current collecting second member are respectively resistance welded to the electrode body, and then collected. The connected current collecting second member is resistance-welded to the electric first member. Hereinafter, the manufacturing procedure of the positive electrode current collecting system will be described with reference to FIGS. 15 to 20, but the negative electrode current collecting system may be performed in the same manner as the positive electrode current collecting system using members having the same shape.

  FIG. 15 is a perspective view showing the shape of the current collecting first member 30. The current collecting first member 30 is an L-shaped current collecting member obtained by processing an aluminum plate, and is connected to the body 30 a for welding to the core exposed portion of the electrode body and the external output terminal 5. Head 30b and a neck 30d connecting the trunk 30a and the head 30b. The head 30b is provided with a mounting hole 30c for fitting the lower end of the external output terminal 5.

  FIG. 16 shows a cross-sectional view of a sealing body portion in which the external output terminal 5, the insulating member 33, and the current collecting first member 30 are attached to the sealing plate 2, and the respective members are integrated. As shown in FIG. 16, provided between the lower surface of the sealing plate 2 and the current collecting first member 30, between the upper surface of the sealing plate 2 and the peripheral edge of the external output terminal 5, and provided on the sealing plate 2. An insulating member 33 is disposed around the through hole 2 a to insulate the sealing plate 2 from the current collecting first member 30 and the external output terminal 5.

  The assembly of the sealing body part is performed as follows. An insulating member 33 is disposed on a predetermined portion of the sealing plate 2. On the insulating member located inside the sealing plate 2, the through hole 2 a of the sealing plate 2 and the mounting hole 30 c of the current collecting first member 30 are positioned so as to overlap each other. Thereafter, the external output terminal 5 is inserted into the through hole 2 a and the mounting hole 30 c of the current collecting first member 30. In this state, the diameter of the lower portion of the external output terminal 5 is expanded, and the external output terminal 5 is caulked and fixed to the sealing plate 2 together with the current collecting first member 30. Thereby, each member is integrated, and the external output terminal 5 and the current collecting first member 30 are connected so as to be energized.

  The current collecting first member 30 fixed to the sealing plate 2 together with the external output terminal 5 in this way is referred to as a current collecting first member connected to the external output terminal.

  Based on FIGS. 17-19, the attachment procedure of the current collection system member to an electrode body is demonstrated. As shown in FIG. 17, of one surface of the body portion 30 a of the current collector first member 30 connected to the external output terminal (the surface on the side in contact with the electrode body core exposed portion), the electrode body core exposed portion The periphery of the first welding planned portion 101 is covered with an insulating film 32 except for the portion to be welded by contacting the first welding planned portion 101. In addition, the insulating film 32 is attached to one surface of the first receiving member 19 except for a portion to be in contact with and welded to the first welding scheduled portion 101.

The body portion 30a of the current collecting first member to which the insulating film 32 is attached is arranged on the left side of the center of the flat portion of the laminated core exposed portion 11c (see FIGS. 2 and 3), and the insulating film 32 is attached to the opposite surface. The worn first receiving member 19 is disposed opposite to the first receiving member 19. Thereafter, the tips of the electrode rods 104 and 104 are brought into contact with the surface of the body 30a of the current collecting first member and the first receiving member 19, respectively, and a current is passed between the two members. Thereby, the trunk | drum 30a of the current collection 1st member, the laminated core exposed part 11c, and the 1st receiving member 19 are resistance-welded.

  Next, the connected current collecting second member 31 is resistance-welded to the other area of the laminated core exposed portion 11c apart from the current collecting first member. The connected current collecting second member 31 used in the embodiment has a shape in which the side connected to the current collecting first member is bent into a "<" shape and rises as shown in FIG. As shown in plan view, the side connected to the current collecting first member is a band-like member having a slightly narrower width. FIG. 20 is a schematic cross-sectional view showing the current collecting system structure of Embodiment 8, and shows a cut surface from the direction of arrows xx in FIG.

  Similarly to the case of the current collector first member, the connection-type current collector second member 31 is also in contact with and welded to the second welding scheduled portion 102 of the electrode body core exposed portion and the current collector first member. An insulating film 32 is attached to the surface facing the laminated core exposed portion 11c except for the portion to be contacted and welded. Further, the insulating film 32 is adhered to one surface of the second receiving member 20 except for a portion to be brought into contact with and welded to the second welding scheduled portion 102.

  Next, the connection-type current collecting second member 31 and the second receiving member 20 to which the insulating film 32 is stuck are applied to other regions of the laminated core exposed portion 11c apart from the current collecting first member, and FIG. Electrical resistance welding as shown.

  Thereafter, as shown in FIG. 19 (a), the upper end of the body portion 30a of the current collector first member is pressed by pressing the tip side portion of the connected current collector second member 31 that is warped in a "<" shape. In this state, as shown in FIG. 19B, the electrode rods 104 and 104 ′ are applied to the current collecting first member 30 and the connected current collecting second member 31 so that a current flows, and the electric resistance Weld. As a result, the electrode body (positive electrode), the connected current collecting second member 31, the current collecting first member 30, and the external output terminal 5 are connected so as to be energized.

  In addition, since the order which connects a current collection 1st member and a current collection 2nd member to an electrode body is not ask | required, after carrying out resistance welding of the connection type | mold current collection 2nd member to a core exposure part first, external output terminal connection The first current collecting member may be resistance welded to the exposed portion of the core, and then both members may be resistance welded. Further, matters other than the matters described above, for example, the material of the current collecting system member, the material of the other battery constituent members, the manufacturing method, and the like may be as described in the first embodiment.

  On the other hand, in this embodiment, although an insulating film is used, the insulating film mainly prevents unnecessary current from being consumed due to contact between members during electric resistance welding. Prior to welding, it is necessary to stick to each member.

  As a material for the insulating film, a thermoplastic insulating film having a melting temperature of 200 ° C. or higher, a welding temperature of 70 ° C. to 150 ° C., and having chemical resistance to the electrolyte is used. For example, a rubber-based sealing material, an acid-modified polypropylene-based heat welding resin, a polyolefin-based heat welding resin, or the like that satisfies this condition is used. In addition, a polyimide tape, a polypropylene tape, a polyphenylene sulfide tape, or the like with a paste material attached to the surface is used.

  The superiority in current collection of the prismatic secondary battery of the present invention will be described by way of examples.

Example 1
A prismatic lithium ion secondary battery of Example 1 was fabricated in the same manner as in Embodiment 3 above.

(Example 2)
A prismatic lithium ion secondary battery of Example 2 was produced in the same manner as in Embodiment 4.

(Reference Example 1)
A prismatic lithium ion secondary battery according to the conventional example shown in FIGS. 21A and 21B was produced. That is, the conventional type current collector plate 201 was resistance-welded to the flat portion of the laminated core body exposed portion 11 c at two locations of the welded portion 1 and the welded portion 2. Except for this, a prismatic lithium ion secondary battery of Reference Example 1 was fabricated in the same manner as in Example 1 above, that is, Embodiment 3.

(Reference Example 2)
As shown in FIG. 22, a current collector plate 202 in which notches 203 are alternately inserted (slit) is provided between the first welding planned portion 101 and the second welding planned portion 102. Resistance welding was performed on the flat portion of the laminated core exposed portion 11c at two locations, the first welding planned portion 101 and the second welding planned portion 102. Except for this, a prismatic lithium ion secondary battery of Reference Example 2 was produced in the same manner as in Example 1 (Embodiment 3).

(Reference Example 3)
As shown in FIG. 23, a current collector plate 204 in which a hole portion 205 is formed between the first weld planned portion 101 and the second weld planned portion 102 is used, and the current collector plate 205 laminated core exposed portion 11 c is formed. Resistance welding was performed on the flat portion at two locations, the first welding planned portion 101 and the second welding planned portion 102. Except for this, a prismatic lithium ion secondary battery of Reference Example 3 was produced in the same manner as in Example 1 (Embodiment 3).

  Each member used in Examples 1 and 2 and Reference Examples 1 to 3 has the same material, thickness, and member width.

[Welding quality]
A plurality of each of the batteries of Examples 1-2 and Reference Examples 1-3 were prepared, and the electrical resistance value of the current collecting system was examined. Moreover, the quality of the welding strength in the 2nd welding part (welding part between the current collection 2nd member and the 2nd receiving member) was investigated. The quality of the welding strength was determined by touching the current collecting second member and the second receiving member by hand with respect to 9 to 13 examples, and whether or not the member moved was determined. These results are shown in Table 1.

  From Table 1, although the resistance value was low in Examples 1 and 2 and Reference Examples 1 and 3, Reference Example 2 had a large resistance value. As for the welding strength, there was no insufficient welding strength in Examples 1 and 2, but there were cases where the welding strength was not sufficient in Reference Examples 1 to 3.

  That is, in Examples 1 and 2, a good resistance value (current collection efficiency) equivalent to that of Reference Example 1 using one current collecting plate was obtained. Moreover, sufficient welding strength was obtained. On the other hand, in Reference Examples 1 to 3, the welding strength may be insufficient, and the welding stability is insufficient compared to Examples 1 and 2. In Reference Example 2, the resistance value was remarkably high.

  This result is considered as follows. In Reference Examples 1 to 3, the reason for the lack of welding strength was as follows. In Reference Examples 1 to 3, when welding the second welding scheduled part, there was a reactive current on the first welded part side that was already welded. This is considered to be due to the fact that welding at the second welded portion becomes insufficient and welding strength is insufficient. In Reference Examples 2 and 3, a slit or a perforated portion is provided between the first weld planned portion and the second weld planned portion, thereby causing a lateral direction (direction between the first weld planned portion and the second weld planned portion). The result of Table 1 is considered to mean that the reactive current cannot be sufficiently reduced even if a slit or a hole is provided. The reason why the resistance value was remarkably increased in Reference Example 2 in which a slit was formed between the first welding scheduled portion and the second welding scheduled portion was that a narrow and long conductive path was formed by providing the slit, This is considered to have increased the resistance value.

(Other matters)
Each of the electrode core body of the first electrode according to the present invention, a current collector first member (or a connected current collector first member), a current collector second member (or a connected current collector second member), and a conductive connecting member However, when it is aluminum or an aluminum alloy, the effects of the present invention are more remarkably exhibited, but these members may be made of different metals. In the above embodiment, each member of the positive electrode is made of aluminum and each member of the negative electrode is made of copper. However, the material of the electrode core is determined according to the characteristics of the electrode. It is not limited to.

  Moreover, in the said embodiment, although the current collection system structure concerning this invention was employ | adopted with respect to both positive and negative electrodes, you may apply this invention method only to one electrode.

  Further, the present invention is not limited to the lithium ion secondary battery but can be applied to the manufacture of other prismatic secondary batteries such as a nickel-hydrogen storage battery and a nickel-cadmium storage battery. Further, in the above embodiment, an example using a flat wound electrode body has been described. However, for a rectangular secondary battery using an electrode body in which flat positive and negative electrode plates are laminated via a separator. Even can be applied.

  Moreover, it is good also as providing the convex part for welding in the part which the electrode stick for welding of each member which is an element of this invention contacts. Providing the convex portion makes it easy to concentrate the current on the weld.

  In the present invention, a method of forming a current collecting system by sequentially welding a plurality of members is adopted. However, according to the manufacturing method of the present invention in which a plurality of members are sequentially welded, the current collection stability and current collecting are improved. A prismatic secondary battery with high output and excellent efficiency can be manufactured with high productivity. Therefore, the industrial applicability of the present invention is great.

In addition, the square secondary battery which concerns on the other invention described in this invention has the following structures.
A flat electrode body including a first electrode and a second electrode;
A rectangular battery case having an opening and a bottom, and accommodating the flat electrode body;
A square rechargeable battery comprising a sealing plate for sealing the opening,
The flat electrode body has a core body exposed portion of the first electrode wound around one end portion and a core body exposed portion of the second electrode wound around the other end portion. ,
When the core exposed portion of the wound first electrode is viewed along the winding axis of the core exposed portion of the wound first electrode, the core exposed of the wound first electrode The portion is a portion having a small thickness in which the core body exposed portion is bundled, a first portion having a thickness larger than that of the portion having a smaller thickness than the portion having the smaller thickness, and located on the sealing plate side. A second portion having a thickness larger than that of the portion having a smaller thickness than the portion having a small thickness.
A current collecting member is resistance-welded to the core exposed portion of the wound first electrode,
The current collecting member has a plate-like first region arranged along the outermost surface on the outermost surface side in the stacking direction of the core exposed portion of the first electrode of the portion having the small thickness, and the first A second region extending from the end of the region on the sealing plate side to the sealing plate side than the end of the sealing plate in the flat electrode body;
At the end of the first region on the sealing plate side, a bent portion that is bent so that the second region is separated from the portion having the small thickness is provided,
A prismatic secondary battery in which an insulating film is disposed between the second region and the outermost surface of the core exposed portion of the wound first electrode.

Moreover, the manufacturing method of the square secondary battery which concerns on the other invention described in this invention has the following structures.
A flat electrode body including a first electrode and a second electrode;
A rectangular battery case having an opening and a bottom, and accommodating the flat electrode body;
A square rechargeable battery comprising a sealing plate for sealing the opening,
The flat electrode body has a core body exposed portion of the first electrode wound around one end portion and a core body exposed portion of the second electrode wound around the other end portion. ,
When the core exposed portion of the wound first electrode is viewed along the winding axis of the core exposed portion of the wound first electrode, the core exposed of the wound first electrode The portion is a portion having a small thickness in which the core body exposed portion is bundled, a first portion having a thickness larger than that of the portion having a smaller thickness than the portion having the smaller thickness, and located on the sealing plate side. A second portion having a thickness larger than that of the portion having a smaller thickness than the portion having a small thickness.
A current collecting member is resistance-welded to the core exposed portion of the wound first electrode,
The current collecting member has a plate-like first region arranged along the outermost surface on the outermost surface side in the stacking direction of the core exposed portion of the first electrode of the portion having the small thickness, and the first A second region extending from the end of the region on the sealing plate side to the sealing plate side than the end of the sealing plate in the flat electrode body;
In the manufacturing method of the prismatic secondary battery, a bent portion is provided at an end portion of the first region on the sealing plate side so that the second region is bent so as to be separated from the portion having the small thickness,
A prismatic secondary battery in which the first region is resistance-welded to the small thickness portion with an insulating film disposed between the second region and the outermost surface of the core exposed portion of the wound first electrode. Manufacturing method.

1 Exterior can
2 Sealing plate
2a Sealing plate through hole
5 Positive external output terminal
6 Negative external output terminal
10 Electrode body
11 Positive electrode plate
11a Positive electrode active material layer
11b Positive electrode core exposed portion
11c Positive electrode laminated core exposed part
12 Negative electrode plate
12a Negative electrode active material layer
12b Negative electrode core exposed part
12c Negative electrode laminated core exposed part
13, 30 Positive electrode current collector first member
14 Positive current collector second member
15 Positive Conductive Connecting Member
16 First member of negative electrode current collector
17 Negative electrode current collector second member
18 Negative electrode conductive connecting member
19 First receiving member
20 Second receiving member
21, 22, 23, 31 Connected current collecting second member
24, 25 Connected current collector first member
26 core notch

30a Current collector first member body
30b Current collector first member head
30c Mounting hole
30d Current collector first member neck

32 Insulation film
33 Insulating material

101 1st welding planned part (1st welding part)
102 Second weld planned part (second weld part)
103 Welding planned part (welded part)
104, 104 'Welding electrode rod
105 Laser for welding

Claims (4)

A flat electrode body including a first electrode and a second electrode;
A rectangular battery case having an opening and a bottom, and accommodating the flat electrode body;
A square rechargeable battery comprising a sealing plate for sealing the opening,
The flat electrode body has a core body exposed portion of the first electrode wound around one end portion and a core body exposed portion of the second electrode wound around the other end portion. ,
When the core exposed portion of the wound first electrode is viewed along the winding axis of the core exposed portion of the wound first electrode, the core exposed of the wound first electrode The portion is a portion having a small thickness in which the core body exposed portion is bundled, a first portion having a thickness larger than that of the portion having a smaller thickness than the portion having the smaller thickness, and located on the sealing plate side. A second portion having a thickness larger than that of the portion having a smaller thickness than the portion having a small thickness.
A current collecting member is resistance-welded to the core exposed portion of the wound first electrode,
The current collecting member has a plate-like first region arranged along the outermost surface on the outermost surface side in the stacking direction of the core exposed portion of the first electrode of the portion having the small thickness, and the first A second region extending from the end of the region on the sealing plate side to the sealing plate side than the end of the sealing plate in the flat electrode body;
At the end of the first region on the sealing plate side, a bent portion that is bent so that the second region is separated from the portion having the small thickness is provided,
A prismatic secondary battery in which an insulating film is disposed between the second region and the outermost surface of the core exposed portion of the wound first electrode. The current collecting member has a region disposed between the sealing plate and the flat electrode body,
2. The prismatic secondary battery according to claim 1, wherein the second region is a portion connecting the first region and a region disposed between the sealing plate and the flat electrode body. A flat electrode body including a first electrode and a second electrode;
A rectangular battery case having an opening and a bottom, and accommodating the flat electrode body;
A square rechargeable battery comprising a sealing plate for sealing the opening,
The flat electrode body has a core body exposed portion of the first electrode wound around one end portion and a core body exposed portion of the second electrode wound around the other end portion. ,
When the core exposed portion of the wound first electrode is viewed along the winding axis of the core exposed portion of the wound first electrode, the core exposed of the wound first electrode The portion is a portion having a small thickness in which the core body exposed portion is bundled, a first portion having a thickness larger than that of the portion having a smaller thickness than the portion having the smaller thickness, and located on the sealing plate side. A second portion having a thickness larger than that of the portion having a smaller thickness than the portion having a small thickness.
A current collecting member is resistance-welded to the core exposed portion of the wound first electrode,
The current collecting member has a plate-like first region arranged along the outermost surface on the outermost surface side in the stacking direction of the core exposed portion of the first electrode of the portion having the small thickness, and the first A second region extending from the end of the region on the sealing plate side to the sealing plate side than the end of the sealing plate in the flat electrode body;
In the manufacturing method of the prismatic secondary battery, a bent portion is provided at an end portion of the first region on the sealing plate side so that the second region is bent so as to be separated from the portion having the small thickness,
A prismatic secondary battery in which the first region is resistance-welded to the small thickness portion with an insulating film disposed between the second region and the outermost surface of the core exposed portion of the wound first electrode. Manufacturing method. The current collecting member has a region disposed between the sealing plate and the flat electrode body,
4. The method for manufacturing a rectangular secondary battery according to claim 3, wherein the second region is a portion connecting the first region and a region disposed between the sealing plate and the flat electrode body. 5.