JP5304626B2 - Lithium ion secondary battery, vehicle and battery-equipped equipment - Google Patents

Description

  The present invention includes a wound-type power generation element (hereinafter also simply referred to as a power generation element) formed by winding a positive electrode plate, a negative electrode plate, a first separator, and a second separator, a positive electrode current collecting member, and a negative electrode current collecting member. The present invention relates to a lithium ion secondary battery, a vehicle equipped with the lithium ion secondary battery, and a battery-equipped device.

In recent years, lithium-ion secondary batteries (hereinafter simply referred to as batteries) that can be charged and discharged have been used as power sources for driving portable electronic devices such as hybrid cars, notebook computers, and video camcorders.
With respect to such a battery, Patent Document 1 discloses a group of electrode plates (winding type power generation elements) that are formed of a strip-like positive electrode plate, a negative electrode plate, and a separator and wound in a spiral shape, and from above and below the electrode plate group. A positive / negative current collector (positive current collector, negative current collector) welded to the tip of the current collector (first positive electrode exposed portion, first negative electrode exposed portion) of each protruding electrode plate A storage battery (lithium ion secondary battery) is disclosed.

JP 2007-280743 A

By the way, in welding between the first positive electrode exposed portion and the positive electrode current collecting member, and welding between the first negative electrode exposed portion and the negative electrode current collecting member, spatter (fine metallic foreign matter) is generated from the welded portion during welding, and the power generation element May scatter toward you. And if the spatter that scatters enters between the separator and the positive electrode plate or between the separator and the negative electrode plate, there is a risk that a short circuit occurs between the positive electrode plate and the negative electrode plate through sputtering.
However, the shape of the power generation element described in Patent Document 1 cannot prevent spatter from entering the power generation element.

  This invention is made | formed in view of this problem, Comprising: It aims at providing the lithium ion secondary battery which suppressed the penetration | invasion of a sputter | spatter into the inside of an electric power generation element. Moreover, it aims at providing the vehicle and battery mounting apparatus which mount such a lithium ion secondary battery.

One aspect of the present invention is a strip-shaped positive electrode current collector foil, and a first positive electrode active material layer and a second positive electrode active material formed on the first positive electrode main surface and the second positive electrode main surface of the positive electrode current collector foil, respectively. And negative electrode current collector foil, and first negative electrode active material layer and second negative electrode active material respectively disposed on the first negative electrode main surface and the second negative electrode main surface of the negative electrode current collector foil A negative electrode plate, each having a strip-shaped first separator and a second separator, and between the first positive electrode active material layer of the positive electrode plate and the second negative electrode active material layer of the negative electrode plate The first separator is interposed between the first negative electrode active material layer of the negative electrode plate and the second positive electrode active material layer of the positive electrode plate, and the positive electrode plate, The negative electrode plate, the first separator and the second separator are wound around a winding axis. A positive electrode current collecting member electrically connected to the positive electrode plate, and a negative electrode current collecting member electrically connected to the negative electrode plate. Located at the end in the first width direction along the winding axis, the first positive electrode main surface and the second positive electrode main surface are exposed in a strip shape from the first positive electrode active material layer and the second positive electrode active material layer. The negative electrode current collector foil is located at an end portion in the second width direction opposite to the first width direction, the first negative electrode main surface and the second negative electrode. The main surface is a lithium ion secondary battery including a first negative electrode exposed portion that is exposed in a strip shape from the first negative electrode active material layer and the second negative electrode active material layer, and the wound power generation element includes: A lithium ion secondary battery having at least one of the following forms A and B.
A. The positive electrode current collector foil includes a second positive electrode exposed portion that is located at an end in the second width direction and at least the second positive electrode main surface is exposed in a strip shape, and the first separator includes the second separator An end portion in the width direction that is bent back radially outward of the winding shaft to surround the end portion in the second width direction of the positive electrode current collector foil, and the second positive electrode exposed portion; A mode in which the negative electrode current collecting member is connected to the first negative electrode exposed portion of the negative electrode current collector foil by welding, including a first bent end portion interposed between the second separator and the second separator.
B. The negative electrode current collector foil is located at an end in the first width direction and includes at least a second negative electrode exposed portion in which the second negative electrode main surface is exposed in a strip shape, and the second separator includes the first separator An end portion in the width direction that is bent back radially outward of the winding shaft to surround the end portion in the first width direction of the negative electrode current collector foil, and the second negative electrode exposed portion; A mode comprising a second bent-back end portion interposed between the first separator and the positive current collecting member connected to the first positive electrode exposed portion of the positive current collector foil by welding.

In the battery described above, the power generation element has at least one of the above-described forms A and B. In the power generation element having the form A, since the first separator includes the first bent end, the negative electrode current collector is formed on the first negative exposed portion located in the second width direction by the first bent end. It is possible to prevent spatter generated when welding the members from entering between the first separator and the positive electrode plate (first positive electrode active material layer). On the other hand, in the power generation element having the form B, since the second separator includes the second bent end, the second bent end provides a positive current collector on the first positive electrode exposed portion located in the first width direction. It is possible to prevent spatter generated when welding the members from entering between the second separator and the negative electrode plate (first negative electrode active material layer).
Thus, it is possible to suppress the spatter generated during welding from entering at least one of the first separator and the first positive electrode active material layer, and the second separator and the first negative electrode active material layer. Therefore, a battery in which occurrence of a short circuit due to sputtering is suppressed can be obtained.

  As the power generation element having the above-described form A, for example, a negative electrode current collector is welded to the first negative electrode exposed portion of the negative electrode current collector foil, and the positive electrode is exposed to the first positive electrode exposed portion of the positive electrode current collector foil. While welding the current collecting member or welding the negative electrode current collecting member to the first negative electrode exposed portion, a method other than welding the positive current collecting member to the first positive electrode exposed portion (for example, bolt fastening) And those that are electrically connected to each other. In addition, as the power generation element having the above-described form B, for example, a positive electrode current collector member is welded to the first positive electrode exposed part and a negative electrode current collector member is welded to the first negative electrode exposed part. The positive electrode current collector is welded to the first positive electrode exposed part, and the negative electrode current collector is electrically connected to the first negative electrode exposed part using a technique other than welding (for example, bolt fastening). Is mentioned.

  Furthermore, in the above-described lithium ion secondary battery, the wound power generation element may be a lithium ion secondary battery having both forms A and B.

  In the battery described above, since the power generation element has both the above-described forms A and B, the second separator, the first negative electrode active material layer, the first separator and the first positive electrode active material layer, In the meantime, it is possible to suppress spatter generated during welding. Therefore, it is possible to obtain a battery in which the occurrence of a short circuit is further suppressed as compared with the battery including the power generation element having the above-described form of only A or B only.

  Furthermore, in any of the above-described lithium ion secondary batteries, in the form A, the first end thickness of the first bent end of the first separator is set to the second positive electrode active material layer. Lithium having a thickness equal to or less than the thickness of the positive electrode layer, and in the form B, the second end thickness of the second folded end portion of the second separator is equal to or less than the thickness of the negative electrode layer of the second negative electrode active material layer. It is preferable to use an ion secondary battery.

In the battery described above, when the power generation element has the form A, the thickness of the first end portion of the first bent end portion interposed between the second positive electrode exposed portion and the second separator is set to the same value as the second positive electrode. The thickness of the positive electrode layer of the second positive electrode active material layer interposed between the exposed portion and the second separator is less than or equal to the thickness. For this reason, a portion where the first bent end portion is interposed between the second positive electrode exposed portion and the second separator is thicker than an adjacent portion adjacent thereto, and the second positive electrode active material layer is formed at the adjacent portion. It is possible to prevent a gap from being generated between the second separator and the second separator.
Further, when the power generation element has the form B, the second end thickness of the second bent back end portion interposed between the second negative electrode exposed portion and the first separator is set to the same value as the second negative electrode exposed portion. The negative electrode layer thickness of the second negative electrode active material layer interposed between the first separator and the first separator is not more than. Therefore, the portion where the first bent end portion is interposed between the second negative electrode exposed portion and the first separator is thicker than the adjacent portion adjacent thereto, and the second negative electrode active material layer is formed at the adjacent portion. And a gap between the first separator and the first separator can be prevented.

  Alternatively, another aspect of the present invention is a vehicle in which the lithium ion secondary battery described in any of the above is mounted and the electric energy stored in the lithium ion secondary battery is used for all or part of the power source. is there.

  Since the above-mentioned vehicle is equipped with a battery that suppresses the occurrence of a short circuit, the vehicle can have a power source that can be used stably.

  The vehicle may be a vehicle that uses electric energy from a battery as a whole or a part of a power source. For example, an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a hybrid railway vehicle, a forklift, an electric wheelchair, an electric vehicle Examples include assist bicycles and electric scooters.

  Alternatively, according to another aspect of the present invention, there is provided a battery in which the lithium ion secondary battery according to any one of the foregoing is mounted and the electric energy stored in the lithium ion secondary battery is used for all or part of the driving energy source. On-board equipment.

  Since the above-described battery-equipped device is equipped with a battery in which the occurrence of a short circuit is suppressed, it can be a battery-equipped device having a drive energy source that can be used stably.

  In addition, as a battery mounting apparatus, what is necessary is just an apparatus which mounts a battery and uses this for all or one part of an energy source, for example, a personal computer, a mobile telephone, a battery-powered electric tool, an uninterruptible power supply, etc. And various home appliances driven by batteries, office equipment, and industrial equipment.

1 is a perspective view of a battery according to Embodiment 1. FIG. 2 is a perspective view of a positive electrode plate of Embodiment 1. FIG. 2 is a perspective view of a negative electrode plate of Embodiment 1. FIG. It is an expanded sectional view (AA part of Drawing 1) of the battery concerning Embodiment 1. It is an expanded sectional view (B section of Drawing 4) of the battery concerning Embodiment 1. It is an expanded sectional view (C section of Drawing 4) of the battery concerning Embodiment 1. FIG. 4 is an explanatory diagram of a battery manufacturing process according to the first embodiment. It is explanatory drawing of the vehicle concerning Embodiment 2. FIG. It is explanatory drawing of the hammer drill concerning Embodiment 3. FIG.

(Embodiment 1)
Next, Embodiment 1 of the present invention will be described with reference to the drawings.
First, the battery 1 according to the first embodiment will be described with reference to FIG.
The battery 1 includes a belt-shaped positive electrode plate 30, a negative electrode plate 40, a first separator 20, and a second separator 25, which are wound around a winding axis AX and are wound-type power generation elements 10. And a positive electrode current collector member electrically connected to the positive electrode plate 30 and a negative electrode current collector member electrically connected to the negative electrode plate 40 (see FIG. 1). In addition, the battery 1 accommodates the electric power generation element 10 in the battery case 80 with the electrolyte solution which is not shown in figure containing lithium ion.

  The battery case 80 has a battery case body 81 and a sealing lid 82 both made of aluminum. Among these, the battery case main body 81 has a bottomed rectangular box shape, and an insulating film (not shown) made of resin and bent into a box shape is interposed between the battery case 80 and the power generation element 10. The sealing lid 82 has a rectangular plate shape, closes the opening of the battery case body 81, and is welded to the battery case body 81. The sealing lid 82 has a positive terminal portion located at the tip of each of a positive current collecting member 71 and a negative current collecting member 72 (described below) connected to the power generation element 10 (the positive electrode plate 30 and the negative electrode plate 40). 71T and the negative electrode terminal part 72T have penetrated, and protrude from the lid | cover surface 82a which faces upwards in FIG. Insulating members 95 made of insulating resin are interposed between the positive electrode terminal portion 91A and the negative electrode terminal portion 92A and the sealing lid 82 to insulate each other. Further, a rectangular plate-shaped safety valve 97 is also sealed on the sealing lid 82.

The positive electrode current collecting member 71 is made of aluminum and has a rectangular plate shape bent in a crank shape. The positive electrode current collecting member 71 includes a positive electrode welded portion 71G welded to the first positive electrode exposed portion 37 of the positive electrode plate 30 of the power generation element 10 and a positive electrode that can be connected to other members (for example, a bus bar) outside the battery 1. Terminal portion 71T.
Further, the negative electrode current collecting member 72 is made of copper and has a rectangular plate shape bent in a crank shape like the positive electrode current collecting member 71. The negative electrode current collecting member 72 includes a negative electrode welded portion 72G welded to the first negative electrode exposed portion 47 of the negative electrode plate 40 of the power generation element 10 and a negative electrode that can be connected to other members (for example, bus bars) outside the battery 1. Terminal portion 72T.

The power generating element 10 is a wound type in which a strip-like positive electrode plate 30 and a negative electrode plate 40 are wound into a flat shape via the strip-like first separator 20 and the second separator 25 (see FIG. 1). . Specifically, the first separator 20 is placed between the first positive electrode active material layer 31 (described later) of the positive electrode plate 30 and the second negative electrode active material layer 42 (described later) of the negative electrode plate 40. The second separator 25 is interposed between the first negative electrode active material layer 41 (described later) and the second positive electrode active material layer 32 (described later) of the positive electrode plate 30 (see FIGS. 4 to 6).
The power generating element 10 includes a positive current collector 71 on a first positive electrode exposed portion 37 of a positive current collector foil 35 described later, and a negative current collector 72 on a first negative electrode exposed portion 47 of a negative current collector foil 45 described later. Are connected by welding. Specifically, in both cases, the positive electrode welded portion 71G of the positive electrode terminal member 71 is connected to the first positive electrode exposed portion 37 and the negative electrode welded portion 72G of the negative electrode terminal member 72 is connected to the first negative electrode exposed portion 47 by resistance welding. Do it.

Among these, as shown in the perspective view of FIG. 2, the positive electrode plate 30 has a strip shape extending in the longitudinal direction DL, and is made of an aluminum positive electrode current collector foil 35, a first positive electrode main surface 35 </ b> A of the positive electrode current collector foil 35, and It has the 1st positive electrode active material layer 31 and the 2nd positive electrode active material layer 32 which are each arrange | positioned at the 2nd positive electrode main surface 35B.
Among these, the first positive electrode active material layer 31 and the second positive electrode active material layer 32 are both positive electrode active material particles (not shown) made of LiCoO ₂ , conductive material (not shown) made of acetylene black, polyfluoride And a binder (not shown) made of vinylidene (PVDF). In addition, the positive electrode layer thickness T32 of each of the first positive electrode active material layer 31 and the second positive electrode active material layer 32 is 35 μm.

Further, the positive electrode current collector foil 35 is located at an end portion in the first width direction DW1, and the first positive electrode main surface 35A and the second positive electrode main surface 35B are the first positive electrode active material layer 31 and the second positive electrode active material layer. The first positive electrode exposed portion 37 exposed in a band shape from 32 and the end of the second width direction DW2 opposite to the first width direction DW1, and the second positive electrode main surface 35B is exposed in a band shape And a second positive electrode exposed portion 38. Since the positive electrode current collector foil 35 is wound in the longitudinal direction DL, the first width direction DW1 and the second width direction DW2 are along the winding axis AX during winding.
The first positive electrode exposed portion 37 of the positive electrode current collector foil 35 is located on the left side in FIG. 1 and is welded to the positive electrode current collector 71 described above (see FIG. 1). On the other hand, the second positive electrode exposed portion 38 is located on the right side in FIG. 1, and between the self and the second separator 25, as shown in FIG. 5, the first bent end of the first separator 20. Part 21 (described later) is interposed.

Further, as shown in the perspective view of FIG. 3, the negative electrode plate 40 has a strip shape extending in the longitudinal direction DL, and is made of a copper negative electrode current collector foil 45 and the first negative electrode main surface 45 </ b> A and the second negative electrode main surface 45 </ b> A of the negative electrode current collector foil 45. It has the 1st negative electrode active material layer 41 and the 2nd negative electrode active material layer 42 which are each arrange | positioned at the negative electrode main surface 45B.
Among these, each of the first negative electrode active material layer 41 and the second negative electrode active material layer 42 includes negative electrode active material particles (not shown) made of graphite and a binder (not shown) made of PVDF. Further, the negative electrode layer thickness T42 of each of the first negative electrode active material layer 41 and the second negative electrode active material layer 42 is 35 μm.

The negative electrode current collector foil 45 is located at the end in the second width direction DW2, and the first negative electrode main surface 45A and the second negative electrode main surface 45B are the first negative electrode active material layer 41 and the second negative electrode active material layer. 42, a first negative electrode exposed portion 47 that is exposed in a band shape, and a second negative electrode exposed portion 48 that is located at the end of the first width direction DW1 and in which the second negative electrode main surface 45B is exposed in a band shape. .
The first negative electrode exposed portion 47 of the negative electrode current collector foil 45 is located on the right side in FIG. 1 and is welded to the negative electrode current collector member 72 described above (see FIG. 1). On the other hand, the second negative electrode exposed portion 48 is located on the right side in FIG. 1, and between the first negative electrode exposed portion 48 and the first separator 20, as shown in FIG. A portion 26 (described later) is interposed.

The first separator 20 made of polyethylene having a thickness of 35 μm includes a first main body portion 22 located between the first positive electrode active material layer 31 and the second negative electrode active material layer 42. The first body portion 22 prevents contact between the positive electrode plate 30 and the negative electrode plate 40.
In addition, as shown in FIG. 6, the first separator 20 is an end portion in the second width direction DW2 and is U-shaped on the outer side (right side in FIG. 6) in the radial direction DR of the winding axis AX. Is bent back to surround the end (second positive electrode exposed portion 38) of the positive electrode current collector foil 35 in the second width direction DW2, and is interposed between the second positive electrode exposed portion 38 and the second separator 25. One bent end 21 is provided.
By forming the first bent end portion 21, spatter generated when the negative electrode current collecting member 72 is welded to the first negative electrode exposed portion 47 located in the second width direction DW <b> 2 is generated in the first separator 20. Intrusion between the 1 main body portion 22 and the first positive electrode active material layer 31 of the positive electrode plate 30 is prevented. The first bent portion 21 has a first end thickness T21 of 35 μm, which is the same as that of the first main body portion 22. The positive electrode layer thickness T32 of the second positive electrode active material layer 32 interposed between the second positive electrode exposed portion 38 and the second separator 25 is also equal.

Similarly to the first separator 20, the second separator 25 made of polyethylene having a thickness of 35 μm has a second main body portion 27 positioned between the first negative electrode active material layer 41 and the second positive electrode active material layer 32. doing. The second main body 27 prevents the positive electrode plate 30 and the negative electrode plate 40 from contacting each other.
In addition to this, as shown in FIG. 5, the second separator 25 is an end portion in the first width direction DW1 and is U-shaped outside the radial direction DR of the winding shaft AX (right side in FIG. 5). Is bent back to surround the end (second negative electrode exposed portion 48) of the negative electrode current collector foil 45 in the first width direction DW1, and is interposed between the second negative electrode exposed portion 48 and the first separator 20. 2 It has a bent end 26.
By forming the second bent-back end portion 26, spatter generated when the positive electrode current collecting member 71 is welded to the first positive electrode exposed portion 37 located in the first width direction DW 1 is generated in the second separator 25. 2 It is prevented from entering between the main body 27 and the first negative electrode active material layer 41 of the negative electrode plate 40. Note that the second end thickness T26 of the second bent-back end portion 26 is 35 μm, which is the same as that of the second main body portion 27. Further, the negative electrode layer thickness T42 of the second negative electrode active material layer 42 interposed between the second negative electrode exposed portion 48 and the first separator 20 is also equal.

As described above, in the battery 1 according to the first embodiment, the first main body portion 22 and the first positive electrode active material layer 31 of the first separator 20, and the second main body portion 27 and the first negative electrode active material of the second separator 25. It can suppress that the sputter | spatter produced at the time of welding enters between the layers 41. FIG. Therefore, it can be set as the battery 1 which suppressed generation | occurrence | production of the short circuit by sputtering.
Further, since the first bent end portion 21 and the second bent end portion 26 are provided, the second negative electrode active material is provided between the second positive electrode active material layer 32 and the second main body portion 27 of the second separator 25. A battery 1 in which spatter hardly enters between the layer 42 and the first main body portion 22 of the first separator 20 can be obtained.

  In the battery 1, the second main body portion 27 of the second separator 25 and the first negative electrode active material layer are also provided between the first main body portion 22 of the first separator 20 and the first positive electrode active material layer 31. It is possible to suppress the spatter generated during welding from entering between 41 and 41. Accordingly, only the form in which the positive electrode current collector foil includes the second positive electrode exposed portion, the first separator includes the first bent end portion, and the negative electrode current collecting member is connected to the first negative electrode exposed portion by welding, or The negative electrode current collector foil includes the second negative electrode exposed portion, the second separator includes the second bent-back end portion, and the power generating element only in a form in which the positive electrode current collecting member is connected to the first positive electrode exposed portion by welding. It can be set as the battery 1 which suppressed generation | occurrence | production of a short circuit further than a battery provided with.

In the power generation element 10, the first end thickness T 21 of the first bent end 21 interposed between the second positive electrode exposed portion 38 and the second separator 25 is the same as the second positive electrode exposed portion 38 and the second positive electrode exposed portion 38. It is equal to the positive electrode layer thickness T32 of the second positive electrode active material layer 32 interposed between the separators 25. Therefore, the portion where the first bent end portion 26 is interposed between the second positive electrode exposed portion 38 and the second separator 25 is thicker than the adjacent portion adjacent thereto, and the second positive electrode is adjacent to the adjacent portion. It is possible to prevent a gap from being generated between the active material layer 32 and the second separator 25.
Further, the second end thickness T26 of the second bent-back end portion 26 interposed between the second negative electrode exposed portion 48 and the first separator 20 is similarly between the second negative electrode exposed portion 48 and the first separator 20. Is equal to the negative electrode layer thickness T42 of the second negative electrode active material layer 42 interposed therebetween. For this reason, in the space between the second negative electrode exposed portion 48 and the first separator 20, the portion where the first bent end portion 21 is interposed is thicker than the adjacent portion adjacent thereto, and the second negative electrode is formed at the adjacent portion. It is possible to prevent a gap from being generated between the active material layer 42 and the first separator 20.

Next, a method for manufacturing the battery 1 according to the first embodiment will be described.
First, the positive electrode plate 30 is produced. Specifically, a paste (not shown) formed by adding and kneading positive electrode active material particles and a conductive material into N-methyl-2-pyrrolidone (NMP) in which a binder is dissolved is used in a longitudinal direction DL. It was applied to the first positive electrode main surface 35A of the strip-shaped positive electrode current collector foil 35 extending in the vertical direction. Note that no paste is applied to both ends of the first positive electrode main surface 35A in the width direction (first width direction DW1, second width direction DW2) of the positive electrode current collector foil 35. As a result, a first positive electrode exposed portion 37 is formed at the end portion in the first width direction DW1, and a second positive electrode exposed portion 38 is formed at the end portion in the second width direction DW2 (see FIG. 2). After the application, the paste on the first positive electrode main surface 35A was dried.
Moreover, the paste was similarly applied to the second positive electrode main surface 35B on the back side of the first positive electrode main surface 35A in the positive electrode current collector foil 35. Note that no paste is applied to the end portion of the second positive electrode main surface 35B in the first width direction DW1 of the positive electrode current collector foil 35. Thereby, the 1st positive electrode exposure part 37 is made in the edge part of the 1st width direction DW1 (refer FIG. 2). After the application, the paste on the second positive electrode main surface 35B was dried.
Thereafter, the paste dried on the first positive electrode main surface 35A and the second positive electrode main surface 35B of the positive electrode current collector foil 35 is compressed by a roll press (not shown), and the first positive electrode active material layer having a positive electrode layer thickness T32 of 35 μm is compressed. A positive electrode plate 30 having 31 and a second positive electrode active material layer 32 was produced (see FIG. 2).

On the other hand, the negative electrode plate 40 is produced. Specifically, the negative electrode active material particles made of graphite described above are introduced into NMP in which the binder is dissolved, and a paste (not shown) formed by kneading is used as a strip-shaped negative electrode current collector foil extending in the longitudinal direction DL. The first negative electrode main surface 45A of 45 was applied. Note that no paste is applied to both ends of the first negative electrode main surface 45A in the width direction (first width direction DW1, second width direction DW2) of the negative electrode current collector foil 45, respectively. Thereby, the first negative electrode exposed portion 47 is formed at the end portion in the second width direction DW2, and the second negative electrode exposed portion 48 is formed at the end portion in the first width direction DW1 (see FIG. 3). After the application, the paste on the first negative electrode main surface 45A was dried.
Further, in the negative electrode current collector foil 45, the paste was similarly applied to the second negative electrode main surface 45B on the back side of the first negative electrode main surface 45A. Note that no paste is applied to the end of the second negative electrode main surface 45B in the second width direction DW2 of the negative electrode current collector foil 45. Thereby, the 1st negative electrode exposure part 47 is made in the edge part of the 2nd width direction DW2 (refer FIG. 3). After the application, the paste on the second negative electrode main surface 45B was dried.
Thereafter, the paste dried on the first negative electrode main surface 45A and the second negative electrode main surface 45B of the negative electrode current collector foil 45 is compressed by a roll press (not shown), and the first negative electrode active material layer having a negative electrode layer thickness T42 of 35 μm is compressed. A negative electrode plate 40 having 41 and a second negative electrode active material layer 42 was produced (see FIG. 3).

  Both the positive electrode plate 30 and the negative electrode plate 40 produced as described above are wound together with the strip-shaped first separator 20 or the second separator 25 to form the power generation element 10. Specifically, the winding is performed in a state where the second separator 25, the negative electrode plate 40, the first separator 20, and the positive electrode plate 30 are stacked in this order from the winding axis AX to the outside in the radial direction DR (FIGS. 4 and 7). reference). At this time, the positive electrode plate 30 and the negative electrode plate 40 are arranged so that the first positive electrode active material layer 31 of the positive electrode plate 30 and the first negative electrode active material layer 41 of the negative electrode plate 40 face inward in the radial direction DR. Accordingly, the first separator 20 is interposed between the first positive electrode active material layer 31 of the positive electrode plate 30 and the second negative electrode active material layer 42 of the negative electrode plate 40, and the first negative electrode active material layer 41 of the negative electrode plate 40, The second separator 25 is interposed between the second positive electrode active material layer 32 of the positive electrode plate 30 (see FIG. 4).

First, the second separator 25 is wound around the winding axis AX, the negative electrode plate 40 is disposed outside the second separator 25 in the radial direction DR, and the second separator 25 is wound around the winding axis AX. (See FIG. 7). Then, in the wound second separator 25, the end portion in the first width direction DW1 is bent back to the outside in the radial direction DR, and the second bend back is turned to the outside in the radial direction DR of the second negative electrode exposed portion 48 of the negative electrode plate 40. An end 26 is formed.
Since the second separator 25 is wound around the winding axis AX, the second bent-back end portion 26 bent back to the outside in the radial direction DR and the diameter of the second bent-back end portion 26 are larger than those of the second bent-back end portion 26. A diameter difference is generated between the second main body 27 of the second separator 25 located inside the direction DR. However, since the second bent-back end portion 26 and the second main body portion 27 are connected, the second bent-back end portion 26 is in close contact with the second main body portion 27 when only the second separator 25 is used. Accordingly, when the second negative electrode exposed portion 48 is positioned between the second bent end portion 26 and the second main body portion 27, the second bent end portion 26 is in close contact with the second negative electrode exposed portion 48. I think that.
Further, when the second separator 25 having the second bent end 26 is wound, the second bent end 26 of the second separator 25 is heated with a heater or the like so that the second separator 25 is easily deformed. Good.

Next, the first separator 20 is disposed outside the negative electrode plate 40 in the radial direction DR, and the positive electrode plate 30 is further disposed outside the first separator 20 in the radial direction DR. The first separator 20 and the positive electrode plate 30 are wound. Wind around axis AX (see FIG. 7). Then, in the same manner as the second separator 25 described above, among the wound first separator 20, the end portion in the second width direction DW 2 is bent back outward in the radial direction DR, and the second positive electrode exposed portion of the positive electrode plate 30. The first bent end 21 is formed outside the radial direction DR of 38.
Since the first separator 20 is wound around the winding axis AX similarly to the second separator 25, a diameter difference is generated between the first bent end portion 21 and the first main body portion 22. Therefore, when the second positive electrode exposed portion 38 is located between the first bent end portion 21 and the first main body portion 22, the first bent end portion 21 is in close contact with the second positive electrode exposed portion 38. I think that.
Further, when winding the first separator 20 having the first bent end 21, like the second separator 25, the first bent end 21 of the first separator 21 is heated with a heater or the like. It is preferable that one separator 20 is easily deformed.

As described above, the wound-type power generation element 10 in which the positive electrode plate 30, the negative electrode plate 40, the first separator 20, and the second separator 25 are wound around the winding axis AX is completed (see FIGS. 1 and 4). ).
Thereafter, the positive electrode welding portion 71G of the positive electrode current collecting member 71 is connected to the first positive electrode exposed portion 37 of the positive electrode plate 30 (positive electrode current collecting foil 35), and the first negative electrode exposed portion 47 of the negative electrode plate 40 (negative electrode current collecting foil 45). The negative electrode welding part 72G of the negative electrode current collecting member 72 was welded to each. Thereafter, the battery case body 81 is inserted into the battery case body 81, and after the electrolyte solution 60 is injected, the battery case body 81 is sealed with a sealing lid 82 by welding. Thus, the battery 1 is completed (see FIG. 1).

(Embodiment 2)
A vehicle 200 according to the second embodiment is equipped with a battery pack 210 including a plurality of the batteries 1 described above. Specifically, as shown in FIG. 8, the vehicle 200 is a hybrid vehicle that is driven by using an engine 240, a front motor 220, and a rear motor 230 in combination. The vehicle 200 includes a vehicle body 290, an engine 240, a front motor 220, a rear motor 230, a cable 250, an inverter 260, and a battery pack 210 having a rectangular box shape. Among these, the battery pack 210 contains a plurality of the batteries 1 described above.

  Since the vehicle 200 according to the second embodiment is equipped with the battery 1 in which the decrease in battery capacity is suppressed, the vehicle 200 having a power source with stable performance can be obtained.

(Embodiment 3)
Further, the hammer drill 300 of the third embodiment is mounted with the battery pack 310 including the battery 1 described above, and is a battery-mounted device having a battery pack 310 and a main body 320 as shown in FIG. Note that the battery pack 310 is accommodated in the bottom portion 321 of the main body 320 of the hammer drill 300.

  Since the hammer drill 300 according to the third embodiment is equipped with the battery 1 in which the decrease in battery capacity is suppressed, it can be a battery-equipped device having a driving energy source with stable performance.

In the above, the present invention has been described with reference to the first to third embodiments. However, the present invention is not limited to the above-described embodiments, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. .
For example, in the first embodiment, the power generation element 10 has both A and B configurations. That is, the positive electrode current collector foil includes a second positive electrode exposed portion, the first separator includes a first bent end, a negative electrode current collecting member is connected to the first negative electrode exposed portion by welding, and Both forms of the negative electrode current collector foil including the second negative electrode exposed part, the second separator including the second bent end part, and the positive electrode current collecting member connected to the first positive electrode exposed part by welding. A wound power generation element having
However, the positive electrode current collector foil includes the second positive electrode exposed portion, the first separator includes the first bent end portion, and the negative electrode current collecting member is connected to the first negative electrode exposed portion by welding. Only, or the negative electrode current collector foil includes a second negative electrode exposed portion, the second separator includes a second bent back end portion, and a positive electrode current collecting member is connected to the first positive electrode exposed portion by welding, B It is good also as a battery provided with the electric power generation element which has only the form of.

  In the first embodiment, in the power generation element 10, the positive electrode current collector is welded to the first positive electrode exposed part, and the negative electrode current collector is welded to the first negative electrode exposed part. However, while the power generation element has the above-described form A, the first positive electrode exposed portion and the positive electrode current collecting member may be electrically connected by a technique (for example, bolt fastening) other than welding. On the other hand, the first negative electrode exposed portion and the negative electrode current collecting member may be electrically connected by a method other than welding (for example, bolt fastening) while the power generating element has the above-described form B.

1 Battery (Lithium ion secondary battery)
10 Power generation elements (winding power generation elements)
20 First separator 21 First bent end 25 Second separator 26 Second bent end 30 Positive electrode plate 31 First positive electrode active material layer 32 Second positive electrode active material layer 35 Positive electrode current collector foil 35A First positive electrode main surface 35B Second positive electrode main surface 37 First positive electrode exposed portion 38 Second positive electrode exposed portion 40 Negative electrode plate 41 First negative electrode active material layer 42 Second negative electrode active material layer 45 Negative electrode current collector foil 45A First negative electrode main surface 45B Second negative electrode Main surface 47 First negative electrode exposed portion 48 Second negative electrode exposed portion 71 Positive electrode current collecting member 72 Negative electrode current collecting member 200 Vehicle 300 Hammer drill (battery mounted device)
AX Winding axis DR Radial direction DW1 First width direction DW2 Second width direction T21 First end thickness T26 Second end thickness T32 Positive electrode layer thickness T42 Negative electrode layer thickness

Claims (5)

A positive electrode plate having a strip-shaped positive electrode current collector foil, and a first positive electrode active material layer and a second positive electrode active material layer respectively disposed on the first positive electrode main surface and the second positive electrode main surface of the positive electrode current collector foil;
A negative electrode plate having a strip-shaped negative electrode current collector foil, and a first negative electrode active material layer and a second negative electrode active material layer respectively disposed on the first negative electrode main surface and the second negative electrode main surface of the negative electrode current collector foil;
Both have a strip-shaped first separator and a second separator,
The first separator, the first negative electrode active material layer of the negative electrode plate, and the positive electrode plate between the first positive electrode active material layer of the positive electrode plate and the second negative electrode active material layer of the negative electrode plate. The second separator is interposed between the second positive electrode active material layer and the positive electrode plate, the negative electrode plate, the first separator, and the second separator are wound around a winding axis. A wound power generation element,
A positive electrode current collecting member electrically connected to the positive electrode plate;
A negative electrode current collecting member electrically connected to the negative electrode plate,
The positive electrode current collector foil is:
Located at the end in the first width direction along the winding axis, the first positive electrode main surface and the second positive electrode main surface are strip-shaped from the first positive electrode active material layer and the second positive electrode active material layer. Including an exposed first positive electrode exposed portion;
The negative electrode current collector foil is
The first negative electrode main surface and the second negative electrode main surface are located at an end in the second width direction opposite to the first width direction, and the first negative electrode active material layer and the second negative electrode active material A lithium ion secondary battery including a first negative electrode exposed portion exposed in a strip shape from a layer,
The wound power generation element is a lithium ion secondary battery having at least one of the following forms A and B.
A. The positive electrode current collector foil includes a second positive electrode exposed portion that is located at an end in the second width direction and at least the second positive electrode main surface is exposed in a strip shape, and the first separator includes the second separator An end portion in the width direction that is bent back radially outward of the winding shaft to surround the end portion in the second width direction of the positive electrode current collector foil, and the second positive electrode exposed portion; A mode in which the negative electrode current collecting member is connected to the first negative electrode exposed portion of the negative electrode current collector foil by welding, including a first bent end portion interposed between the second separator and the second separator.
B. The negative electrode current collector foil is located at an end in the first width direction and includes at least a second negative electrode exposed portion in which the second negative electrode main surface is exposed in a strip shape, and the second separator includes the first separator An end portion in the width direction that is bent back radially outward of the winding shaft to surround the end portion in the first width direction of the negative electrode current collector foil, and the second negative electrode exposed portion; A mode comprising a second bent-back end portion interposed between the first separator and the positive current collecting member connected to the first positive electrode exposed portion of the positive current collector foil by welding. The lithium ion secondary battery according to claim 1,
The wound power generation element is a lithium ion secondary battery having both forms A and B. The lithium ion secondary battery according to claim 1 or 2,
In the form of A, the first end thickness of the first bent end of the first separator is less than or equal to the positive electrode layer thickness of the second positive electrode active material layer,
The lithium ion secondary battery in which the second end thickness of the second bent back end portion of the second separator is set to be equal to or less than the negative electrode layer thickness of the second negative electrode active material layer in the form B. A vehicle on which the lithium ion secondary battery according to any one of claims 1 to 3 is mounted and the electric energy stored in the lithium ion secondary battery is used for all or part of a power source. A battery-equipped device in which the lithium ion secondary battery according to any one of claims 1 to 3 is mounted and the electric energy stored in the lithium ion secondary battery is used for all or a part of a drive energy source. .

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