JP2009087612A - Layered battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a layered battery capable of lessening a connection resistance value between both electrodes and both terminals and restraining deterioration of a cycle characteristic of the battery by controlling generation of fluctuated connection resistance values even though charging and discharging is carried out at a high rate. <P>SOLUTION: A projected section 341 is extended on an opposite surface 34b of a positive electrode side holding plate 34, a recessed section 311 is extended on an opposite surface 31b of an internal terminal 31 at a loosely fitting state, and a positive electrode current collection tab 11 is arranged between the recessed section 311 and the projected section 341. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stacked battery used in, for example, a robot, an electric vehicle, a backup power source, and the like, and more particularly to a stacked lithium ion battery that can insulate a lid and a terminal with a simple structure.

  In recent years, batteries have been used not only for power sources of mobile information terminals such as mobile phones, notebook personal computers, and PDAs, but also for robots, electric vehicles, backup power sources, etc., and further increase in capacity is required. It has become like this. In response to such demands, lithium ion secondary batteries have high energy density and high capacity, and are therefore widely used as drive power sources as described above.

  As a battery form of such a lithium ion secondary battery, it is broadly divided into a cylindrical one in which a spiral electrode body is arranged in a bottomed cylindrical exterior body, and a laminated electrode body in which a plurality of rectangular electrodes are laminated. There is a laminated type arranged in the exterior body. Among these lithium ion secondary batteries, the specific structure of the laminated electrode body of the latter battery is that a sheet-like positive electrode having a positive current collecting tab and a sheet-like negative electrode having a negative current collecting tab are interposed via a separator. A plurality of the positive electrode current collecting tabs are electrically connected to the positive electrode terminal in a state where a plurality of the positive electrode current collecting tabs are stacked, while a plurality of the negative electrode current collecting tabs are stacked in a negative electrode state. This structure is electrically connected to the terminal.

Here, as a connection method (connection structure) between both current collecting tabs and both terminals, the following is proposed.
(1) A method in which the current collecting tabs are wrapped together and caulked, and a bundling part (or a projecting piece) for bundling the current collecting tabs is provided, and the current collecting tabs are fused and integrated with both current collecting terminals via the bundling parts. (See Patent Documents 1 and 2 below).
(2) A method in which the current collecting tab is caulked while being inserted into at least one slit provided in the current collecting block (see Patent Document 3 below).

JP-A-8-167407 JP-A-8-167408 JP 2005-12951 A

  Here, in recent years, as described above, the capacity of the lithium ion secondary battery has been increased, and accordingly, the number of stacked positive electrodes and negative electrodes tends to increase. There may be a site where the contact state between the current collecting tabs is not good. For this reason, the connection resistance value between both poles and both terminals tends to increase as a whole, and the connection resistance value between each electrode plate and terminal tends to vary. For this reason, particularly when charging / discharging at a high rate, if the connection resistance value increases as a whole, a sufficient output cannot be obtained, and if the connection resistance value varies, The flowing current value becomes non-uniform (specifically, a large current flows in a portion where the connection resistance value between both electrodes and both terminals is small, while a small current flows in a region where the connection resistance value between both electrodes and both terminals is large. Current flows), and the charge / discharge state is unevenly distributed in the battery, resulting in partial overdischarge and overcharge. For this reason, the cycle characteristics when charging / discharging at a high rate are deteriorated. Therefore, even when the number of stacked positive electrodes and negative electrodes is increased, it is necessary to suppress an increase in the connection resistance value as a whole and variations in the connection resistance value.

However, in the battery of (1) above, the surface of the bundling component or the like for bundling the current collecting tab (the surface that comes into contact with the current collecting tab) is flat, so that when the caulking is fixed, the current collecting tab is extremely limited. A large pressure is applied to the other part (usually the end of the current collecting tab), while no large pressure is applied to the other parts. Therefore, the contact area between the current collecting tabs is reduced overall, and the contact area between the current collecting tabs is greatly different for each part, and the connection resistance value between both electrodes and both terminals is increased, In addition, there is a problem that the connection resistance value varies.
Also, in the battery of (2) above, the surface of the slit into which the current collecting tab is inserted (the surface in contact with the current collecting tab) is flat. Has a problem.

  The present invention takes the above-mentioned problems into consideration, and performs charge / discharge at a high rate by reducing the connection resistance value between both electrodes and both terminals and suppressing the variation in the connection resistance value. Even if it is a case, it is providing the laminated battery which can suppress that the cycling characteristics of a battery fall.

  To achieve the above object, the present invention has a laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators, and a positive electrode current collecting tab made of a metal foil from the positive electrode, A negative electrode current collecting tab made of a metal foil is extended from the negative electrode, and the positive electrode current collecting tab is overlapped, and a plate-like internal terminal forming a part of the positive electrode terminal and a plate-like positive electrode side The positive electrode and the positive electrode terminal are electrically connected via a positive electrode current collecting tab while being sandwiched by a holding plate, while the negative electrode current collecting tab is overlapped with a part of the negative electrode terminal. A laminated battery having a structure in which the negative electrode and the negative electrode terminal are electrically connected via a negative electrode current collecting tab by being sandwiched between a plate-like internal terminal and a plate-like negative electrode side holding plate. A pair of the positive terminal and the positive side holding plate One of the surfaces is provided with a convex portion extending in the width direction of the positive current collector tab, while the other opposing surface is provided with a concave portion in which the convex portion is loosely fitted. A structure in which a positive electrode current collecting tab is disposed between the uneven portions and / or one of the opposed surfaces of the internal terminal of the negative electrode terminal and the negative electrode side pressing plate is provided on the opposite surface of the negative electrode current collecting tab. While a convex portion extending in the width direction is provided, a concave portion in which the convex portion is arranged in a loose fit state is extended on the other facing surface, and a negative electrode current collecting tab is arranged between the concave and convex portions. It is characterized by providing.

If it is the said structure, there exists the following effect. In addition, since the structure on the positive electrode side and the structure on the negative electrode side are the same structure, the following description of the function and effect will be made taking the positive electrode side as an example.
As described above, a convex portion is provided on one opposing surface of the opposing surfaces of the plate-like internal terminal that forms part of the positive electrode terminal and the positive-side holding plate, while the convex portion is provided on the other opposing surface. If the concave portion arranged in a loosely fitted state is extended and the positive electrode current collecting tab is arranged between the concave and convex portions, the area of the facing surface between the internal terminal and the positive side holding plate increases, The contact area between the terminal and the positive electrode current collecting tab is increased, and the connection resistance value between the positive electrode and the positive electrode terminal is reduced as a whole. In addition, if the positive electrode current collecting tab is arranged between the concavo-convex parts, the positive electrode current collecting tab and the internal terminal always come into contact with each other at the convex part or the corner part of the concave part. Since a large pressing force is applied to the current collecting tabs, the probability that the positive electrode current collecting tabs come into contact with each other increases. Therefore, not only the connection resistance value between the positive electrode and the positive electrode terminal is reduced as a whole, but also the connection resistance between each positive electrode and the positive electrode terminal is made uniform.

It is desirable that the internal terminal of the positive electrode terminal and the positive electrode side holding plate are fixed by screws and / or the internal terminal of the negative electrode terminal and the negative electrode side holding plate are fixed by screws.
The internal terminal of the positive electrode terminal and the positive electrode side holding plate can be fixed with a clip or the like, but in this configuration, the pressure applied to the positive electrode current collecting tab becomes small when the battery is used for a long time, The resistance value may increase. On the other hand, when both are fixed with screws, such inconvenience can be solved.

It is desirable that a plurality of portions fixed with screws are provided in the width direction of each current collecting tab.
If the screws are fixed at a plurality of locations, the applied pressure applied to the positive electrode current collecting tab is increased, and the applied pressure is applied evenly to the positive electrode current collecting tab.

  It has a laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators, and a positive electrode current collecting tab made of metal foil from the positive electrode and a negative electrode current collector made of metal foil from the negative electrode Each of the tabs is extended, and the positive current collecting tab is overlapped, and is sandwiched between a plate-like internal terminal that forms a part of the positive electrode terminal and a plate-like positive-side holding plate, thereby While the positive electrode and the positive electrode terminal are electrically connected via a positive electrode current collecting tab, the negative electrode current collecting tab is overlapped, and a plate-like internal terminal that forms a part of the negative electrode terminal and a plate-like electrode A laminated battery having a structure in which the negative electrode and the negative electrode terminal are electrically connected via a negative electrode current collecting tab by being sandwiched between negative electrode side holding plates, and the internal terminal of the positive electrode terminal and the positive electrode At least one of the opposing surfaces of the side presser plate When a convex part is provided and a convex part is provided on both opposing surfaces, a positive electrode current collecting tab is disposed between the convex parts, and when a convex part is provided only on one opposing surface, the convex part is provided. And / or a structure in which a positive electrode current collecting tab is disposed between the surface and the opposing surface, and / or a convex portion is provided on at least one of the opposing surfaces of the internal terminal of the negative electrode terminal and the negative electrode side holding plate. When the convex portions are provided on both opposing surfaces, a negative electrode current collecting tab is disposed between the convex portions, and when the convex portions are provided only on one opposing surface, the convex portions and the opposing surfaces It has the structure where a negative electrode current collection tab is arrange | positioned between.

  With the above configuration, since the positive electrode current collecting tab is sandwiched only between the convex portions or between the convex portion and the opposing surface, the contact area between the positive electrode terminal, the positive electrode current collecting tab, and the positive electrode current collecting tabs Is considered to be smaller. However, when viewed microscopically, the surfaces of the positive electrode terminal and the positive electrode current collecting tab are not completely mirror-finished and have minute irregularities. Therefore, when the convex part is not formed on the opposing surface of the plate-like internal terminal that forms part of the positive electrode terminal and the plate-like negative electrode side holding plate, the positive electrode current collecting tab is sandwiched across the entire opposing surface. Will be. For this reason, the pressure applied to the positive electrode current collector tab is dispersed, and the positive electrode current collector tab does not deform so much. Therefore, the contact area between the positive electrode terminal, the positive electrode current collector tab, and the positive electrode current collector tabs is extremely high. Get smaller. On the other hand, if the positive electrode current collector tab is sandwiched only between the convex portions or between the convex portion and the opposing surface, the applied pressure applied to the positive electrode current collector tab is not dispersed, and the positive electrode current collector tab is Since it is intensively applied to the sandwiched portion, the positive electrode current collecting tab existing in the sandwiched portion is easily deformed, and as a result, the contact area between the positive electrode terminal, the positive electrode current collecting tab, and the positive electrode current collecting tab is large. Become.

  In the caulking and fixing shown in the above prior art, a large pressing force is applied only to a very limited part of the current collecting tab, so that the contact at the part is good, but the contact area between the positive electrode current collecting tabs is good. Cannot be increased. On the other hand, if it is the said structure, since a big pressurization force will be added by a certain amount of area between convex parts or between a convex part and an opposing surface, increase of contact areas, such as positive electrode current collection tabs, is increased. Can be achieved. Taking this into consideration, it is preferable to make the area ratio of the convex portion to the total area of the contact surface too small, although it depends on the force of clamping the positive electrode current collecting tab between the internal terminal and the negative electrode side holding plate. In general, the area ratio is most effective in the range of 60% to 80%.

The internal terminal of the positive electrode terminal and the positive side holding plate are preferably screwed and / or the internal terminal of the negative electrode terminal and the negative side holding plate are preferably screwed and the screw is fixed. It is desirable that a plurality of portions are provided in the width direction of each current collecting tab.
This is the same reason as described above.

It is desirable that the screw is fixed at a position corresponding to the convex portion.
If the screw is fixed at a position corresponding to the convex portion as in the above configuration, a large pressure is surely applied to the positive electrode current collecting tab between the convex portions or between the convex portion and the opposing surface.

  The laminated electrode body is housed in a space composed of a rectangular cylindrical outer casing and a rectangular plate-shaped lid fixed to the opening end of the outer casing, and both the positive and negative terminals are the inner terminals. A columnar external terminal that protrudes to the outside through the hole formed in the lid and is connected to an external device, and the internal terminal is fixed to the surface on the battery internal side, while the external terminal is on the battery external side. A connecting plate fixed to the surface, and a columnar insulator is interposed between the connecting plate and the lid, and one member of the insulator and the lid is a first member. While the fitting portion is provided, the other member is provided with a first fitted portion, and one member of the insulator and the connecting plate is provided with a second fitting portion, while the other member is provided with the other fitting member. The member is provided with a second fitted portion, and the internal terminal extends in the longitudinal direction of the lid, One, the first fitted portion, said first fitting portion, the second fitted portion, and the plan view shape of the second fitting portion that forms a substantially rectangular shape desired.

  As in the above configuration, if the first fitting portion is provided on one member of the insulator and the lid, the first fitting is provided if the first fitting portion is provided on the other member. The insulator and the lid are aligned by fitting the part and the first fitted part, and one of the insulator and the connecting plate is provided with the second fitting part. If the second fitted portion is provided on the other member, the insulator and the connecting plate are aligned by fitting the second fitted portion and the second fitted portion. Because of these, the lid and the connection plate are aligned via the insulator, so the alignment between the hole formed in the lid and the external terminal fixed to the connection plate is also possible. Will be done. Therefore, since it is possible to prevent the lid and the external terminal from coming into contact with each other in the hole formed in the lid, alignment between the hole formed in the lid and the external terminal can be performed with a simple configuration. As a result, the manufacturing process can be prevented from becoming complicated, and the manufacturing cost can be reduced.

  In this case, the shape of the first fitting portion, the first fitting portion, the second fitting portion, and the second fitting portion in a plan view may be circular, but the internal terminal is If these are plate-shaped and are circular, the extension direction of the internal terminals is the desired direction (generally, the direction parallel to the width direction of both current collecting tabs fixed to the positive and negative electrodes) In other words, an external force acts to bend both poles and current collecting tabs. Therefore, if the first fitted portion, the first fitted portion, the second fitted portion, and the second fitted portion are square, the extending direction of the internal terminal is set to a desired direction. Since this state can be maintained, the external force can be prevented from acting.

When the external terminal protrudes from a substantially central portion in the width direction of the lid body, the external terminal is fixed to a substantially central portion of the connection plate, while the internal terminal is fixed to an end portion of the connection plate. It is desirable that
In this way, if the external terminal protrudes from the substantially central portion in the width direction of the lid body, the internal terminal is arranged in the longitudinal direction of the exterior body while ensuring convenience when connecting the battery to the external device. Since it is arranged close to the side surface, the space in the exterior body can be effectively used for improving the internal connection efficiency.

It is desirable that the positive electrode active material used for the positive electrode and the negative electrode active material used for the negative electrode are made of a material capable of occluding and releasing lithium.
When applied to a lithium ion battery composed of a material in which the positive electrode active material and the negative electrode active material are capable of occluding and releasing lithium, the high rate is achieved when the number of stacked positive and negative electrode plates is increased in the battery and the capacity is increased. Cycle characteristics can be significantly improved.

  According to the present invention, it is possible to reduce the connection resistance value between the two electrodes and both terminals and to suppress the variation in the connection resistance value. Also has an excellent effect of suppressing the deterioration of the cycle characteristics of the battery.

  Hereinafter, a stacked lithium ion battery according to an example of the present invention will be described with reference to FIGS. The laminated battery according to the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

(Structure of stacked lithium-ion battery)
As shown in FIGS. 3 and 4, the stacked lithium ion battery is composed of two separators, in which a bag-like separator 3 and a negative electrode 2 in which a positive electrode 1 is arranged are alternately arranged, and an outermost position. Has a laminated electrode body 10 having a structure in which the negative electrode 2 is disposed. Since the negative electrode 2 is disposed at the outermost position, the laminated electrode body 10 is configured such that the number of the negative electrodes 2 is one more than the number of the positive electrodes 1 (specifically, the positive electrode 1 has 50 sheets, negative electrode 2 is composed of 51 sheets). Note that reference numeral 14 in FIG. 3 denotes a slip prevention tape for suppressing the displacement of the positive electrode 1 and the negative electrode 2 in the laminated electrode body 10, and the negative electrode 2 existing on the outermost side across the laminated electrode body 10. The both ends are stuck on.

  The laminated electrode body 10 is enclosed with an electrolyte in an outer can 21 made of aluminum as shown in FIG. 1, and a lid 20 made of aluminum is welded and fixed to the open end of the outer can 21. Has been. From the lid 20, an external terminal 33 that forms part of a positive electrode terminal 30 that will be described later and is formed with a thread, and an external terminal 43 that forms part of a negative electrode terminal 40 that is described later and is formed with a thread. The external terminal 33 is fixed to the lid 20 with a nut 24a through a ring-shaped insulating member 22a and a washer 23a, and the external terminal 43 is connected to the ring-shaped insulating member 22b and the washer 23b. And is fixed to the lid body 20 with a nut 24b.

As shown in FIG. 5A, the positive electrode 1 has a positive electrode active material made of LiCoO ₂ and carbon on both surfaces of a positive electrode conductive core made of a square aluminum foil (thickness: 15 μm). A positive electrode active material layer 1a composed of a conductive agent made of black and a binder made of polyvinylidene fluoride is provided. The positive electrode 1 has a width L1 of 95 mm and a height L2 of 115 mm. From one side of the positive electrode 1, the positive electrode 1 is integrally formed with the positive electrode conductive core and the positive electrode active material layer 1a is provided. The positive electrode current collecting tab 11 (width L3 is 30 mm, height L4 is 20 mm) is protruding.

  As shown in FIG. 5 (c), the bag-like separator 3 is formed by superposing two polypropylene (PP) separators 3 a and fusing the separators 3 a around the separator 3 a ( (Width: 2 mm) 4 is provided. By setting it as such a structure, the said positive electrode 1 can be accommodated in the bag-shaped separator 3. FIG. As shown in FIG. 5B, the separator 3a has a rectangular shape with a width L5 of 100 mm, a height L6 of 120 mm, and a thickness of 30 μm.

  As shown in FIG. 6, the negative electrode 2 has a negative electrode active material composed of a negative electrode active material made of natural graphite and a binder made of polyvinylidene fluoride on the entire surface of both sides of a rectangular negative electrode conductive core. The material layer 2a is provided. The negative electrode 2 has a width L7 of 100 mm and a height L8 of 120 mm, which is the same size as the separator 3a. Further, from one side of the negative electrode 2, the negative electrode current collecting tab 12 which is integrally formed with the negative electrode conductive core and is not provided with the negative electrode active material layer 2a (width L9 is 30 mm, height L10 is 20 mm). Has a protruding structure.

Here, the power supply taking-out structure from the laminated electrode body 10 will be described taking the positive electrode side as an example.
As shown in FIG. 2, when the power supply is taken out from the laminated electrode body 10, the positive electrode terminal 30, the positive electrode side holding plate 34, three screws 35, rubber packing 25 (second annular packing), insulation The body 26, the rubber packing 27 (first annular packing), the lid 20, the insulating member 22a, the washer 23a, the nut 24a, and the like are used.

  The positive electrode terminal 30 is made of aluminum, and as shown in FIGS. 8 and 9, a plate-like internal terminal 31 connected to the positive electrode 1 and a circle protruding outward from the lid 20 and connected to an external device. It has a columnar external terminal 33 and a connection plate 32 in which the internal terminal 31 is fixed to the end surface on the battery internal side, while the external terminal 33 is fixed to a substantially central portion on the battery external side. The connection plate 32 has a substantially square shape in plan view. In addition, although the said internal terminal 31, the said external terminal 33, and the said connection board 32 are integrally molded, the structure which manufactures each member separately and fixes these by welding etc. may be sufficient.

The positive current collecting tab 11 is sandwiched between the internal terminal 31 and the positive side holding plate 34 by using the internal terminal 31 and the positive side holding plate 34 having the following structure.
As shown in FIGS. 10 and 11, two convex portions extending in the width direction (D direction in FIG. 3) of the positive electrode current collecting tab 11 are provided on the surface 34 b facing the internal terminal 31 in the positive electrode side holding plate 34. 341 is provided, and an R portion 341 a is formed at the tip of the convex portion 341. Further, a screw hole 34 a that is screwed with the three screws 35 is formed at the center in the width direction of the positive electrode side holding plate 34. The reason why the three screws 35 are used in this manner is that if the screws are fixed at a plurality of positions, the pressure applied to the positive electrode current collecting tab 11 is increased, and the positive pressure current collecting tab 11 is equally applied with pressure. is there.
In addition, the distance L18 between the screw hole 34a located at both ends of the screw hole 34a and the end portion of the positive electrode side holding plate 34 is 5 mm, and the distance L17 between the screw holes 34a is 10 mm. The positive side holding plate 34 has a width L14 of 30 mm, a height L15 of 10 mm, and a thickness L19 of 3 mm. The convex portion 341 has a width L16 of 2 mm and a height L20 of 1 mm.

On the other hand, as shown in FIGS. 8 and 9, the opposing surface 31b of the internal terminal 31 is provided with two recesses 311 extending in the width direction of the positive electrode current collecting tab 11 (D direction in FIG. 3). An R portion 311 a is formed at the tip of the recess 311. Further, a screw hole 31 a for inserting the three screws 35 is formed in the central portion in the width direction of the internal terminal 31.
The positive side holding plate 34 has a thickness L11 of 3 mm, and the recess 311 has a width L13 of 2 mm and a depth L12 of 1 mm.

  Here, when the positive electrode current collecting tab 11 is sandwiched between the internal terminal 31 and the positive electrode side holding plate 34, as shown in FIGS. 2 and 7 (the screw 35 is omitted in FIG. 7). In addition, the internal terminal 31 and the positive electrode side holding plate 34 are screw-fixed in a state where the positive electrode current collecting tab 11 is disposed between the opposing surface 34 b of the positive electrode side holding plate 34 and the opposing surface 31 b of the internal terminal 31. . In this case, as shown in FIG. 12, since the R portion 341a is formed at the tip of the convex portion 341, and the R portion 311a is formed at the tip of the concave portion 311, the tip of the convex portion 341 is tapered. On the other hand, the opening of the tip of the recess 311 is large. Therefore, although the width L16 of the convex portion 341 and the width L13 of the concave portion 311 are both 2 mm and are the same, the tip of the convex portion 341 is loosely fitted into the concave portion 311 while the positive electrode current collecting tab 11 is sandwiched. It will be.

  The structure in which only the tip of the convex portion 341 is loosely fitted in the concave portion 311 may be such that the height L20 of the convex portion 341 and the depth L12 of the concave portion 311 are both 1 mm, The thickness of one electric tab 11 is 15 μm, and even if 50 sheets are stacked, the maximum is 750 μm (0.75 mm). Therefore, the height L20 of the convex portion 341 and the depth L12 of the concave portion 311 and the stacked positive electrode collection This is because the thickness of the stacked electric tabs 11 is substantially equal. In consideration of this, when the height L20 of the convex portion 341 and the depth L12 of the concave portion 311 are larger than the above-described values, the width L16 of the convex portion 341 is set to the width L13 of the concave portion 311. It is desirable to make it narrower (for example, when the thickness of the stacked positive electrode current collecting tabs 11 is 0.75 mm, the width L16 of the convex portion 341 is 1.5 mm [0.75 × 2] It is desirable to make it narrower. With such a structure, even if the height L20 of the convex portion 341 and the depth L12 of the concave portion 311 are larger than the above-described values, the convex portion 341 is sandwiched between the positive electrode current collecting tabs 11. This is because is loosely fitted in the recess 311.

The R portions 341a and 311a are formed at the leading end of the convex portion 341 and the leading end of the concave portion 311 in addition to the above-described reason, and the damage to the positive electrode current collecting tab 11 due to the angular tip end is reduced. Because.
Further, the internal terminal 41 of the negative electrode terminal 40 and the negative electrode current collecting tab 12 are fixed, as shown in FIG. 19, the internal terminal 41 of the negative electrode terminal 40 having the same structure as the internal terminal 31 of the positive electrode terminal 30, The negative electrode side holding plate 44 and the screw 35 having the same structure as the positive side holding plate 34 are used. However, the difference is that the internal terminal 31 of the positive electrode terminal 30 and the internal terminal 41 of the negative electrode terminal 40 are arranged in opposite directions (arranged in a state rotated by 180 °). In FIG. 19, reference numeral 411 denotes a concave portion, and 441 denotes a convex portion.

  The insulator 26 is made of PEEK (polyether ether ketone) which has a substantially prismatic shape (the shape in plan view is a substantially square shape), is excellent in chemical resistance, insulation, and workability, is high in strength, and is easily available. Become. Further, as shown in FIGS. 14 and 15, a concave second fitted portion 26 a having the same shape as the outer shape of the connection plate 32 is formed on the inner side surface (surface in the battery internal direction) of the insulator 26. The connecting plate (second fitting portion) 32 of the positive electrode terminal 30 is fitted into the second fitted portion 26 a and the positive electrode terminal 30 is fixed to the insulator 26. An annular groove 26c is formed on the contact surface 26b (surface that contacts the connection plate 32) of the insulator 26, while the contact surface (surface that contacts the insulator 26) 32a of the connection plate 32 described above. As shown in FIGS. 8 and 9, etc., an annular groove 32b having the same shape as the groove 26c is formed at a position corresponding to the groove 26c. And when the connection board 32 is fitted by the 2nd to-be-fitted part 26a, a battery can be sealed by arrange | positioning the said packing 25 in the space formed by two groove | channels 26c and 32b. . An insertion hole 26e through which the external terminal 33 is inserted is formed in the protrusion 26d formed at the center of the back surface of the insulator 26. On the other hand, as shown in FIGS. 13 and 15, an annular groove 26f having the same shape as the groove 26c is formed on the outer surface of the insulator 26 (surface in the battery exterior direction).

  As shown in FIGS. 16 to 18, a hole 20 a having a diameter larger than that of the external terminal 33 of the positive electrode terminal 30 is formed in the lid body 20, and the inside surface of the lid body 20 is outside the hole 20 a. A concave first fitted portion 20d having the same shape as the outer shape of the insulator 26 is formed on the (surface in the battery internal direction). An insulator (first fitting portion) 26 is fitted into the first fitted portion 20 d, and the insulator 26 is fixed to the lid body 20. Further, an annular recess 20f corresponding to the groove 26f of the insulator 26 is formed on the contact surface 20e (surface that contacts the insulator 26) of the lid 20, and the insulator 26 is the first. The battery can be sealed by disposing the packing 27 in the space formed by the groove 26f and the recessed portion 20f when fitted into the fitted portion 20d. The packings 25 and 27 were made of rubber (made by DuPont, trade name: Kalrez) having a small compression set (excellent sealing property) and excellent chemical resistance and heat resistance.

  The lid 20 is formed with an electrolyte injection port 20c, and the electrolyte injection port 20c is sealed by a sealing plate (not shown). The attachment structure of the negative electrode terminal 40 in the lid 20 is substantially the same structure as the attachment structure of the positive electrode terminal 30, and the difference is that the internal structure of the negative electrode terminal 40 in the battery is as shown in FIG. The terminal 41 is disposed so as to face the internal terminal 31 of the positive electrode terminal 30, and the negative electrode terminal 40 (the internal terminal 41, the connection plate 42, and the external terminal 43) has a nickel plated copper surface. Is used.

  As in the above configuration, the convex portion 341 extends on the facing surface 34b of the positive electrode side holding plate 34, while the concave surface 311 in which the convex portion 341 is arranged in a loosely fitted state is formed on the facing surface 31b of the internal terminal 31. If the positive electrode current collecting tab 11 is disposed between the concavo-convex portions 311 and 341, the area of the facing surface between the internal terminal 31 and the positive electrode side pressing plate 34 increases. The contact area with the current collecting tab 34 is increased, and the connection resistance value between the positive electrode 1 and the positive electrode terminal 30 is reduced as a whole. In addition, if the positive electrode current collecting tab 11 is arranged between the concave and convex portions 311 and 341, the positive electrode current collecting tab 11 and the internal terminal 31 are always at the corners of the convex portion 341 and the concave portion 311. In addition, since a large pressing force is applied to the positive electrode current collecting tab 11 at the portion, the probability that the positive electrode current collecting tabs 11 are in contact with each other increases. Therefore, not only the connection resistance value between the positive electrode 1 and the positive electrode terminal 30 is reduced as a whole, but also the connection resistance between each positive electrode 1 and the positive electrode terminal 30 is made uniform.

  Further, if the first fitted portion 20d having the same shape as the outer shape of the insulator 26 is formed on the inner side surface (surface in the battery internal direction) of the lid 20, the first fitted portion 20d By fitting the insulator (first fitting portion) 26, the insulator 26 is fixed to the lid 20, and the insulator 26 and the lid 20 are aligned. Further, if the second fitted portion 26a having the same shape as the outer shape of the connection plate 32 is formed on the inner side surface (surface in the battery internal direction) of the insulator 26, the second fitted portion. By fitting the connecting plate (second fitting portion) 32 of the positive electrode terminal 30 to 26a, the positive electrode terminal 30 is fixed to the insulator 26 and the insulator 26 and the positive electrode terminal 30 are aligned. Become. For these reasons, the lid 20 and the positive terminal 30 are aligned via the insulator 26, so that the gap between the hole 20 a formed in the lid 20 and the external terminal 33 of the positive terminal 30 is between. Will also be aligned. As a result, it is possible to prevent the lid 20 and the external terminal 33 from coming into contact with each other in the hole 20 a formed in the lid 20.

Further, the first fitted portion 20d, the insulator 26, the second fitted portion 26a, and the connection plate 32 all have a substantially square shape in plan view. Since the positive terminal 30 can be prevented from rotating, the extending direction of the internal terminal 31 (direction C in FIG. 2) and the width direction of the positive current collecting tab 11 (direction D in FIG. 3) are parallel. State is maintained. Therefore, it is possible to prevent an external force from bending the positive electrode 1 and the positive electrode current collecting tab 11 from acting.
The same applies to the negative electrode side.

(Production method of stacked lithium-ion battery)
[Production of positive electrode]
90% by mass of LiCoO ₂ as a positive electrode active material, 5% by mass of carbon black as a conductive agent, 5% by mass of polyvinylidene fluoride as a binder, N-methyl-2-pyrrolidone as a solvent ( NMP) solution was mixed to prepare a positive electrode slurry. Next, this positive electrode slurry was applied to both surfaces of an aluminum foil (thickness: 15 μm) as a positive electrode current collector. Then, after drying the solvent and compressing to a thickness of 0.1 mm with a roller, it was cut so as to have the above-described width L1 and height L2 and the positive electrode current collecting tab protruded to produce a positive electrode.

[Production of bag-shaped separator with positive electrode arranged inside]
After preparing two PP separators and arranging the positive electrode between the separators, the periphery of the separator was thermally welded to produce a bag-like separator in which the positive electrode was arranged inside. The width of the fused part was 2 mm.

(Production of negative electrode)
A slurry was prepared by mixing 95% by mass of graphite powder as a negative electrode active material, 5% by mass of polyvinylidene fluoride as a binder, and an NMP solution as a solvent. As a copper foil (thickness: 10 μm). Thereafter, the solvent was dried and compressed to a thickness of 0.08 mm with a roller, and then cut so that the width L7 and the height L8 were as described above and the negative electrode current collector tab protruded, thereby producing a negative electrode.

[Production of battery]
The negative electrode 2 (51 sheets) obtained as described above and the bag-like separator 3 (50 sheets) in which the positive electrode 1 is disposed are alternately laminated to obtain a laminated electrode body 10 as shown in FIG. Was made. Note that the negative electrode 2 was disposed at the end of the laminated electrode body 10 in the laminating direction. Next, a misalignment prevention tape 14 was attached to the four sides of the multilayer electrode body 10 so as to straddle the multilayer electrode body 10.

  Next, as shown in FIG. 19, the 50 positive electrode current collecting tabs 11 protruding from the laminated electrode body 10 are arranged between the internal terminal 31 and the positive electrode side holding plate 34, and then the screw 35. The screw portion was inserted into the insertion hole 34a and the positive electrode current collecting tab 11, and the screw 35 and the screw hole 31a were screwed together. Thereby, as shown in FIG. 7, the positive electrode current collecting tab 11 is sandwiched between the internal terminal 31 and the positive electrode side holding plate 34. After this, as shown in FIG. 20 (for ease of understanding, only the packings 25 and 27 are perspective views), a connecting plate is provided between the lid 20 and the connecting plate 32 of the positive terminal 30. The packing 25, the insulator 26, and the packing 27 are arranged in this order from the side 32, and furthermore, as shown in FIG. 21, the insulator 26 is fitted to the lid 20 and the connection plate 32 is fitted to the insulator 26, and fixed. did. Finally, as shown in FIG. 22, the nut 24a was screwed to the external terminal 33 via the insulating member 22a and the washer 23a. In the above description, the positive electrode side was described, but the same processing was performed on the negative electrode side. Finally, the lid 20 was welded to the exterior body 21 to complete the battery.

(Other matters)
(1) In the above-described embodiment, the convex portion 341 is provided on the facing surface 34b of the positive-side holding plate 34, and the concave portion 311 is provided on the facing surface 31b of the internal terminal 31, but the present invention is limited to this structure. Instead, as shown in FIG. 23, a structure in which a concave portion 342 is provided on the opposing surface of the positive electrode side pressing plate 34 and a convex portion 312 is provided on the opposing surface 31 b of the internal terminal 31 may be employed.

(2) In the above embodiment, the convex portion 341 is loosely fitted into the concave portion 311. However, as shown in FIGS. 24 and 25, the positive electrode side on which the convex portions 343 and 344 are formed on the opposing surface 34b. 26, a structure in which the positive electrode current collecting tab 11 is sandwiched between the convex portions 343, 344, and 312 as shown in FIG. 26, or an uneven surface 31b of the internal terminal 31 as shown in FIG. The structure which clamps the positive electrode current collection tab 11 with the convex parts 343 and 344 of the positive electrode side pressing board 34, and the opposing surface 31b of the internal terminal 31 may be sufficient.

Such a configuration has the following effects.
As shown in FIG. 28 and FIG. 29, the surface of the internal terminal 31 is not in a perfect mirror surface state, and there are minute protrusions 31e (the positive electrode current collecting tab 11 is the same, but for the sake of easy understanding, FIG. In FIG. 29, the protrusion 31e is formed only on the surface of the internal terminal 31). Therefore, there is no concavo-convex portion formed on the opposing surface of the internal terminal 31 and the positive electrode side holding plate 34, and if the positive electrode current collecting tab 11 is sandwiched across the entire opposite surface, the additional force applied to the positive electrode current collecting tab 11 is applied. Since the pressure is dispersed, the positive electrode current collecting tab is not so deformed as shown in FIG. Therefore, the contact area between the internal terminal 31, the positive electrode current collector tab 11, and the positive electrode current collector tabs 11 is extremely small.

  On the other hand, if it is the structure which clamps the positive electrode current collection tab 11 only between convex part 343,344,312 as mentioned above or between convex part 343,344 and the opposing surface 31b, the positive electrode current collection tab 11 is included. Since the applied pressure is not dispersed but concentratedly applied to the sandwiched portion, as shown in FIG. 29, the positive electrode current collecting tab 11 existing at the sandwiched portion is easily deformed. Therefore, the contact area between the internal terminal 31, the positive electrode current collector tab 11, and the positive electrode current collector tabs 11 increases.

  When the positive current collecting tab 11 is sandwiched between the convex portions 343, 344, 312, or between the convex portions 343, 344 and the facing surface 31 b of the internal terminal 31, the extending direction of the convex portion 343 is positive electrode collection. It is not limited to the width direction of the electric tab 11 (D direction in FIG. 3), and may be a direction perpendicular to the width direction of the positive electrode current collecting tab 11, as shown in FIGS. 30 and 31. A configuration in which convex portions having a square shape or a circular shape in plan view are provided on the facing surface 31 b of the internal terminal 31 or the facing surface 34 b of the positive electrode side pressing plate 34 may be employed.

(3) The positive electrode active material is not limited to the above LiCoO ₂ , but may be LiNiO ₂ , LiMnO _4, or a composite thereof, and the negative electrode active material is not limited to the above natural graphite. Artificial graphite or the like may be used.

(4) In the above examples, the negative electrode active material layers were formed on both surfaces of the negative electrode conductive core for all the negative electrodes 2, but the negative electrode active material layers (specifically, not facing the positive electrode) There may be no negative electrode active material layer) present outside the outermost negative electrode. And if it is such a structure, since the thickness of a laminated electrode body will become small, the high capacity density of a battery can be achieved.

  The present invention can be applied to, for example, a battery used for a robot, an electric vehicle, a backup power source, and the like.

It is a perspective view of the laminated battery of the present invention. It is a disassembled perspective view which shows the attachment structure of the positive electrode terminal in the laminated battery of this invention. It is a perspective view of the laminated electrode body used for the laminated battery of this invention. It is a disassembled perspective view of the laminated electrode body used for the laminated battery of this invention. It is a figure which shows a part of laminated battery of this invention, Comprising: The figure (a) is a top view of a positive electrode, The figure (b) is a perspective view of a separator, The figure (c) is a positive electrode arrange | positioned inside. It is a top view which shows the bag-shaped separator. It is a top view of the negative electrode used for the laminated battery of this invention. It is a side view which shows the state by which the positive electrode current collection tab is arrange | positioned between the internal terminal of a positive electrode terminal, and the positive electrode side pressing board. It is a side view of the positive electrode terminal used for the laminated battery of this invention. It is a front view of the positive electrode terminal used for the laminated battery of this invention. It is a front view of the positive electrode side pressing plate used for the laminated battery of the present invention. It is a side view of the positive electrode side pressing plate used for the laminated battery of this invention. It is explanatory drawing which shows the contact state of the internal terminal of a positive electrode terminal, a positive electrode side pressing board, and a positive electrode current collection tab. It is the perspective view which looked at the insulator used for the laminated battery of this invention from the upper side. It is the perspective view which looked at the insulator used for the laminated type battery of this invention from the lower side. It is AA arrow sectional drawing of FIG. It is a top view of the cover used for the laminated battery of the present invention. It is a bottom view of the cover used for the laminated battery of the present invention. FIG. 17 is a cross-sectional view taken along line B-B in FIG. 16. It is a perspective view which shows the manufacturing method of the laminated battery of this invention. It is explanatory drawing which shows the manufacturing method of the laminated battery of this invention. It is sectional drawing which shows the manufacturing method of the laminated battery of this invention. It is sectional drawing which shows the manufacturing method of the laminated battery of this invention. It is a side view which shows the modification of the state by which the positive electrode current collection tab is arrange | positioned between an internal terminal and the positive electrode side pressing board. It is a front view which shows the modification of the positive electrode side pressing plate used for the laminated battery of this invention. It is a side view which shows the modification of the positive electrode side pressing plate used for the laminated battery of this invention. It is a side view which shows the other modification of the state by which the positive electrode current collection tab is arrange | positioned between an internal terminal and the positive electrode side pressing board. It is a side view which shows the further another modification of the state by which the positive electrode current collection tab is arrange | positioned between an internal terminal and the positive electrode side pressing board. It is explanatory drawing which shows the state of the positive electrode current collection tab in the surface of an internal terminal. It is explanatory drawing which shows the state of the positive electrode current collection tab in the surface of an internal terminal. It is a front view which shows the other modification of the positive electrode side pressing plate used for the laminated battery of this invention. It is a side view which shows the other modification of the positive electrode side pressing plate used for the laminated battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Positive electrode 2: Negative electrode 3: Bag-shaped separator 10: Laminated electrode body 11: Positive electrode current collection tab 12: Negative electrode current collection tab 20: Lid 20d: 1st to-be-fitted part 26: Insulator 26a: 2nd to-be-fitted Joint portion 26e: Insertion hole 30: Positive terminal 31: Internal terminal 31b: Opposing surface 311: Concave surface 32: Connection plate 33: External terminal 34: Positive side holding plate 34b: Confronting surface 341: Convex portion

Claims (10)

It has a laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators, and a positive electrode current collecting tab made of metal foil from the positive electrode and a negative electrode current collector made of metal foil from the negative electrode Each of the tabs is extended, and the positive current collecting tab is overlapped, and is sandwiched between a plate-like internal terminal that forms a part of the positive electrode terminal and a plate-like positive-side holding plate, thereby While the positive electrode and the positive electrode terminal are electrically connected via a positive electrode current collecting tab, the negative electrode current collecting tab is overlapped, and a plate-like internal terminal that forms a part of the negative electrode terminal and a plate-like electrode A laminated battery having a structure in which the negative electrode and the negative electrode terminal are electrically connected via a negative electrode current collecting tab by being sandwiched between negative electrode side pressing plates,
One of the opposing surfaces of the internal terminal of the positive electrode terminal and the positive electrode side pressing plate is provided with a convex portion extending in the width direction of the positive electrode current collecting tab, while the convex portion is provided on the other opposing surface. Is a structure in which a concave portion arranged in a loosely fitted state is extended, and a positive electrode current collecting tab is arranged between the concave and convex portions, and / or an opposing surface of the internal terminal of the negative electrode terminal and the negative electrode side holding plate One of the opposing surfaces is provided with a convex portion extending in the width direction of the negative electrode current collector tab, while the other opposing surface is provided with a concave portion in which the convex portion is loosely fitted. A laminated battery comprising a structure in which a negative electrode current collecting tab is disposed between the portions.   The laminated battery according to claim 1, wherein the internal terminal of the positive electrode terminal and the positive electrode side holding plate are fixed by screws and / or the internal terminal of the negative electrode terminal and the negative electrode side holding plate are fixed by screws.   The stacked battery according to claim 2, wherein the screw-fixed portion is provided in a plurality of locations in the width direction of each current collecting tab. It has a laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators, and a positive electrode current collecting tab made of metal foil from the positive electrode and a negative electrode current collector made of metal foil from the negative electrode Each of the tabs is extended, and the positive current collecting tab is overlapped, and is sandwiched between a plate-like internal terminal that forms a part of the positive electrode terminal and a plate-like positive-side holding plate, thereby While the positive electrode and the positive electrode terminal are electrically connected via a positive electrode current collecting tab, the negative electrode current collecting tab is overlapped, and a plate-like internal terminal that forms a part of the negative electrode terminal and a plate-like electrode A laminated battery having a structure in which the negative electrode and the negative electrode terminal are electrically connected via a negative electrode current collecting tab by being sandwiched between negative electrode side pressing plates,
A convex portion is provided on at least one of the opposing surfaces of the internal terminal of the positive electrode terminal and the positive side holding plate, and a positive electrode is provided between the convex portions when the convex portions are provided on both opposing surfaces. In the case where a current collecting tab is arranged and a convex portion is provided only on one opposing surface, a structure in which a positive current collecting tab is arranged between the convex portion and the opposing surface, and / or the negative electrode terminal A convex portion is provided on at least one of the opposing surfaces of the internal terminal and the negative electrode side holding plate, and when the convex portions are provided on both opposing surfaces, a negative electrode current collecting tab is provided between the convex portions. A stacked battery comprising a structure in which a negative electrode current collecting tab is disposed between a convex portion and an opposing surface when the convex portion is provided only on one opposing surface.   5. The stacked battery according to claim 4, wherein the internal terminal of the positive electrode terminal and the positive electrode side holding plate are fixed by screws and / or the internal terminal of the negative electrode terminal and the negative electrode side holding plate are fixed by screws.   The stacked battery according to claim 5, wherein a plurality of portions fixed with screws are provided in the width direction of each current collecting tab.   The stacked battery according to claim 5 or 6, wherein the battery is fixed with a screw at a position corresponding to the convex portion.   The laminated electrode body is housed in a space composed of a rectangular cylindrical outer casing and a rectangular plate-shaped lid fixed to the opening end of the outer casing, and both the positive and negative terminals are the inner terminals. A columnar external terminal that protrudes to the outside through the hole formed in the lid and is connected to an external device, and the internal terminal is fixed to the surface on the battery internal side, while the external terminal is on the battery external side. A connecting plate fixed to the surface, and a columnar insulator is interposed between the connecting plate and the lid, and one member of the insulator and the lid is a first member. While the fitting portion is provided, the other member is provided with a first fitted portion, and one member of the insulator and the connecting plate is provided with a second fitting portion, while the other member is provided with the other fitting member. The member is provided with a second fitted portion, and the internal terminal extends in the longitudinal direction of the lid, The planar view shape of the first fitting portion, the first fitting portion, the second fitting portion, and the second fitting portion is substantially square. The stacked battery according to claim 1.   When the external terminal protrudes from a substantially central portion in the width direction of the lid body, the external terminal is fixed to a substantially central portion of the connection plate, while the internal terminal is fixed to an end portion of the connection plate. The stacked battery according to claim 8.   The stacked battery according to claim 1, wherein the positive electrode active material used for the positive electrode and the negative electrode active material used for the negative electrode are made of a material capable of occluding and releasing lithium.

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