JP2011086406A - Lithium ion secondary battery, vehicle, and battery-mounted device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery capable of suppressing insertion of lithium ion into a second negative electrode part of a negative electrode active material layer when charging, and suppressing degradation of a battery capacity, and to provide a vehicle with the lithium ion secondary battery and a battery-mounted device. <P>SOLUTION: The lithium ion secondary battery 1 includes a positive electrode plate 30, a negative electrode plate 40 having the negative electrode active material layer 41, a separator 20, and an electrolyte solution 60. The negative electrode active material layer is composed of a first negative electrode part 42 opposed to the positive electrode material layer 31 with the separator interposed and a second negative electrode part 43 having no opposing positive electrode material layer. The separator includes a first separator part 22 which is opposed to the first negative electrode part and is porous and capable of permeating lithium ion in its own thickness direction DC and a second separator part 23 opposed to the second negative electrode part. Part of the second separator part is made to be more difficult to permeate lithium ion in the thickness direction DC than the first separator part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lithium ion secondary battery comprising a positive electrode plate having a positive electrode active material layer, a negative electrode plate having a negative electrode active material layer, and a separator, a vehicle equipped with this lithium ion secondary battery, and a battery-equipped device. About.

In recent years, lithium ion secondary batteries (hereinafter also simply referred to as batteries) have been used as power sources for driving portable electronic devices such as hybrid cars, notebook computers, and video camcorders.
In Patent Document 1, the width of the active material coating portion (negative electrode active material layer) of the negative electrode plate (negative electrode plate) is made larger than the width of the active material coating portion (positive electrode active material layer) of the positive electrode plate (positive electrode plate). Further, a wound type lithium ion secondary battery set to be larger is disclosed.

JP 2005-190913 A

By the way, in the battery of Patent Document 1, the negative electrode active material layer is located on both ends of the first negative electrode portion facing the positive electrode active material layer via the separator and the width direction (short direction) of the negative electrode active material layer. And a second negative electrode part in which no positive electrode active material layer is opposed through a separator.
In this battery, electrons can be exchanged not only between the first negative electrode portion and the negative electrode current collector plate but also between the second negative electrode portion and the negative electrode current collector plate. For this reason, when this battery is charged, lithium ions released from the positive electrode active material layer are inserted into the opposing first negative electrode portion, and the lithium ions move so as to spread outward from the end portion of the positive electrode active material layer. And it is inserted also into the inside of the 2nd negative electrode part.
However, since this second negative electrode portion does not have an opposing positive electrode active material layer, it is difficult to release lithium ions therein from this second negative electrode portion during discharge. That is, the second negative electrode portion is a negative electrode active material layer, but only absorbs lithium ions and hardly participates in discharge. For this reason, the amount of lithium ions that can be released from the negative electrode active material layer during discharge is reduced by the amount of lithium ions inserted into the second negative electrode portion during charging, that is, the battery capacity is reduced. End up.

  The present invention has been made in view of such problems, and can suppress the decrease in battery capacity by suppressing the insertion of lithium ions into the second negative electrode portion of the negative electrode active material layer during charging. An object of the present invention is to provide a lithium ion secondary battery, a vehicle equipped with the lithium ion secondary battery, and a battery-equipped device.

  One embodiment of the present invention is a positive electrode current collector plate having conductivity, a positive electrode plate having a positive electrode active material layer disposed on the positive electrode current collector plate, a negative electrode current collector plate having conductivity, and A negative electrode plate having a negative electrode active material layer disposed on the negative electrode current collector plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte containing lithium ions. The negative electrode active material layer includes a first negative electrode portion that faces the positive electrode active material layer via the separator, and a positive electrode active material layer that faces the positive electrode active material layer via the separator. A second negative electrode portion that does not exist, and the separator is opposed to the first negative electrode portion, and has a porous first separator portion that can transmit lithium ions in its thickness direction, and the second negative electrode portion. A second separator portion facing each other, and At least a portion of the second separator unit is different from the aforementioned first separator unit, a lithium ion secondary battery formed by a transparent hard portion itself of the thickness direction transmission of lithium ions is a difficult form.

  In the battery described above, at least a part of the second separator portion is a difficult-to-penetrate portion in which it is difficult for lithium ions to permeate in its own thickness direction as compared to the first separator portion. For this reason, when the battery is charged, it is possible to suppress the insertion of lithium ions into the second negative electrode portion, particularly the portion facing the difficult-to-permeate portion, thereby suppressing the decrease in battery capacity. it can.

In addition, as a battery, the winding type battery which has a wound type electric power generation element which all winds through a separator between a strip-like positive electrode plate and a negative electrode plate, a plurality of positive electrode plates, and a plurality of Examples include a stacked battery having a stacked power generation element in which negative electrode plates are alternately stacked via separators.
Moreover, as the difficult-to-permeate part, it has porosity, but in addition to the part where the porosity is lower than that of the first separator part, there are also parts that do not have through-holes and do not allow lithium ions to permeate. included. In addition, as a technique for lowering the porosity of the difficult-to-permeate portion as compared with the first separator portion, for example, the porous separator is thermally compressed to make the difficult-to-permeate portion, or a solvent is applied to dissolve the separator to obtain pores. Or by filling a porous separator with a member made of a material that is difficult to permeate lithium ions, bonding (bonding), pasting or coating the porous separator. Can be mentioned.

  Further, in the above-described lithium ion secondary battery, the difficult-to-transmit portion may be a lithium-ion secondary battery that is a non-transmittable portion formed by making lithium ions impermeable in its thickness direction.

  In the battery described above, the difficult-to-permeate part is an impervious part that is impervious to lithium. Therefore, when the battery is charged, lithium is placed in a portion of the second negative electrode part that faces the difficult-to-transmit part (non-permeable part). It is possible to reliably suppress the insertion of ions.

  The non-permeable portion may be a portion where lithium ions cannot be permeated in its thickness direction. For example, a portion formed by thermally compressing a porous separator to completely close the through-hole, a solvent A part made of a material that does not allow lithium ions to permeate into a part where the separator is melted to completely fill the through hole, a part containing a resin-containing solution to close the hole, and a porous separator The site | part formed by carrying | supporting, adhere | attaching (bonding), sticking or apply | coating is mentioned.

  Furthermore, in the lithium ion secondary battery described above, the positive electrode plate, the negative electrode plate, and the separator each having a strip shape extending in the longitudinal direction are wound in the longitudinal direction to form a wound power generation element. Of the strip-like negative electrode active material layers extending in the longitudinal direction, the second negative electrode portion includes short end-side second negative electrode portions positioned on both ends in the short direction, and the second separator portion is And a strip-shaped short end side second separator portion located on both ends in the short direction and extending in the longitudinal direction, wherein the short end side second separator portion is a lithium ion comprising the difficult to transmit portion. A secondary battery is recommended.

  The above-described battery includes a wound-type power generation element, and the short-side second separator portion includes a portion that is difficult to transmit. In the strip-shaped negative electrode active material layer extending in the longitudinal direction, the short-side second negative electrode portion occupies most of the second negative electrode portion. Therefore, the short end side second separator portion made of the difficult-to-penetrate portion faces here, so that the lithium ions inserted into the second negative electrode portion can be greatly reduced when the battery is charged. It is possible to sufficiently suppress the decrease in battery capacity due to.

  Or the other aspect of this invention is a vehicle which mounts one of the above-mentioned lithium ion secondary batteries, and uses the electrical energy stored in this lithium ion secondary battery for all or one part of a motive power source.

  Since the above-mentioned vehicle is equipped with a battery that suppresses a decrease in battery capacity, it can be a vehicle having a power source with stable performance.

  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, electric Examples include assist bicycles and electric scooters.

  Alternatively, according to another aspect of the present invention, a battery-mounted device in which any one of the above-described lithium ion secondary batteries is mounted and the electric energy stored in the lithium ion secondary battery is used for all or part of the driving energy source. It is.

  Since the battery-mounted device described above is mounted with a battery in which a decrease in battery capacity is suppressed, it can be a battery-mounted device having a drive energy source with stable performance.

  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 according to Embodiment 1. FIG. 3 is a perspective view of a negative electrode plate according to Embodiment 1. FIG. It is a perspective view of the separator of Embodiment 1. It is an expanded sectional view (AA part of Drawing 1) of the battery concerning Embodiment 1. 6 is a perspective view of a battery according to a first modification. FIG. It is a perspective view of the positive electrode plate of modification 1. It is a perspective view of the negative electrode plate of modification 1. It is a perspective view of the separator of modification 1. 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 an electrolytic solution 60 containing lithium ions, each of which includes a strip-like positive electrode plate 30, a negative electrode plate 40, and a separator 20 extending in the longitudinal direction DA. The positive electrode plate 30, the negative electrode plate 40, and the separator 20 are provided. Is a lithium ion secondary battery that is wound in the longitudinal direction DA to form a wound power generation element 10 (see FIG. 1). In addition, the battery 1 accommodates the electric power generation element 10 in the battery case 80, as shown in FIG.

  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. Of the positive electrode current collecting member 91 and the negative electrode current collecting member 92 connected to the power generation element 10, the positive electrode terminal portion 91 </ b> A and the negative electrode terminal portion 92 </ b> A located at the tips of the sealing lid 82 pass through, respectively. 1 protrudes from the lid surface 82a facing upward. 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.

In addition, the electrolytic solution 60 was prepared by adding LiPF ₆ as a solute to a mixed organic solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were adjusted to EC: EMC = 3: 7 by volume ratio, and lithium ions were added. This is a non-aqueous electrolyte having a concentration of 1 mol / l.

  The power generation 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 a strip-like separator 20 (see FIG. 1). Only the separator 20 is wound on the outermost and innermost sides of the power generation element 10. The positive electrode plate 30 and the negative electrode plate 40 of the power generation element 10 are joined to a plate-like positive current collector 91 or negative current collector 92 bent in a crank shape, respectively (see FIG. 1).

Among these, the positive electrode plate 30 has a strip shape extending in the longitudinal direction DA, as shown in the perspective view of FIG. 2, and the aluminum foil 38 made of aluminum and the longitudinal direction DA on both main surfaces of the aluminum foil 38, respectively. And two positive electrode active material layers 31 arranged in a strip shape extending in the direction.
The positive electrode active material layer 31 includes positive electrode active material particles (not shown) made of LiCoO ₂ , a conductive material (not shown) made of acetylene black, and a binder (not shown) made of polyvinylidene fluoride (PVDF). including.

Further, as shown in the perspective view of FIG. 3, the negative electrode plate 40 has a strip shape extending in the longitudinal direction DA and a copper copper foil 48 and strips extending in the longitudinal direction DA on both main surfaces of the copper foil 48. And two negative electrode active material layers 41, 41 disposed on the surface.
Among these, the negative electrode active material layer 41 includes negative electrode active material particles (not shown) made of graphite and a binder (not shown) made of PVDF.

As shown in FIG. 3 and FIG. 5 of the enlarged cross-sectional view (AA portion) of FIG. 1, the negative electrode active material layer 41 is a first negative electrode facing the positive electrode active material layer 31 through the separator 20. Part 42 and a second negative electrode part 43 (short end side second negative electrode part 44 and long end side second negative electrode part 45 described below) in which the positive electrode active material layer 31 opposed via the separator 20 does not exist. .
More specifically, the area of the negative electrode active material layer 41 is larger than that of the positive electrode active material layer 31 facing the negative electrode active material layer 41. Of the negative electrode active material layer 41, the first negative electrode portion 42 is located at the center of each of the longitudinal direction DA and the short direction DB of the negative electrode active material layer 41, while the second negative electrode portion 43 is the first negative electrode portion. It is located in a frame shape around 42 (see FIG. 3). For this reason, when the battery 1 is charged, it is possible to prevent metallic lithium from being deposited on the copper foil 48 located at the periphery of the negative electrode active material layer 41.

  Among these, the second negative electrode portion 43 includes two long-end-side second negative electrode portions 45 and 45 positioned on both ends in the longitudinal direction DA of the negative electrode active material layer 41 and the short-side direction DB of the negative electrode active material layer 41. It consists of two short-end-side second negative electrode portions 44, 44 positioned on both ends (see FIG. 3). It should be noted that the position of the boundary between the second negative electrode portion 43 (the short end side second negative electrode portion 44 and the long end side second negative electrode portion 45) and the first negative electrode portion 42 in the negative electrode active material layer 41 is the negative electrode plate 40. It is determined when the power generation element 10 is formed by winding the separator 20 and the positive electrode plate 30.

  4 and 5, the strip-shaped separator 20 made of polyethylene and extending in the longitudinal direction DA is opposed to the first negative electrode portion 42, and is a porous first that can transmit lithium ions in its thickness direction DC. Separator part 22, second separator part 23 (short end side second separator part 24 and long end side second separator part 25 described later), positive electrode active material layer 31, and negative electrode active part facing second negative electrode part 43. It consists of a third separator portion 27 (a short end side third separator portion 28 and a long end side third separator portion 29 described below) that does not contact any of the material layers 41.

Among these, the 3rd separator part 27 is located in the short end side 3rd separator part 28 and 28 located in the both ends side of the transversal direction DB of the separator 20, respectively, and the both ends side of the longitudinal direction DA of the separator 20, respectively. It comprises longitudinal end side third separator portions 29, 29 (see FIG. 4). One of the longitudinal end side third separator portions 29, 29 is wound by itself and arranged near the innermost shaft core of the power generation element 10, and the other covers the outermost side of the power generation element 10. Be placed.
In addition, the short end side third separator part 28 is a non-permeable part formed in a form incapable of transmitting lithium ions in the thickness direction DC, similarly to the adjacent short end side second separator part 24 described below. Has been. In addition, the long-end-side third separator portion 29 is similar to the first separator portion 22, the long-length third permeable portion 29 </ b> A that can transmit lithium ions, and the short-end-side second separator portion 24 is not permeable. And a third third non-transparent portion 29B.

  The second separator portion 23 is positioned between the longitudinal direction DA of the separator 20 and the first separator portion 22 and the longitudinal third transmission portions 29A and 29A of the two longitudinal end side third separator portions 29 and 29, respectively. Two longitudinal end side second separator portions 25, 25, short side direction DB of separator 20, and both end sides between first separator portion 22 and two short end side third separator portions 28, 28, respectively. It consists of two short end side second separator portions 24, 24 (see FIG. 4). The long end side second separator portion 25 is the long end side second negative electrode portion 45 of the negative electrode active material layer 41, and the short end side second separator portion 24 is the short end of the negative electrode active material layer 41. Opposite side second negative electrode portions 44 (refer to FIG. 5 for the short-side second separator portion 24). Therefore, the first separator portion 22 and the second separator portion 23 in the separator 20 (short end side second separator portion 24 and long end side second separator portion 25) and the third separator portion 27 (long end end side first) The position of the boundary with the three separator portions 29) is also determined when the power generating element 10 is formed by winding the negative electrode plate 40, the separator 20, and the positive electrode plate 30.

Among the second separator parts 23, the short-side second separator part 24 is a difficult-to-penetrate part in which it is difficult to transmit lithium ions in the thickness direction DC as compared with the porous first separator part 22. It is said that. More specifically, the short end-side second separator 24 is a non-transmittable part. For this reason, when the battery 1 is charged, a portion of the second negative electrode portion 43 of the negative electrode active material layer 41 that faces the short-end-side second separator portion 24, that is, the short-end-side second negative-electrode portion 44. Lithium ions can be prevented from being inserted into the battery, and a decrease in battery capacity can be suppressed.
On the other hand, in the second separator portion 24, the long-end-side second separator portion 25 is in a porous form like the first separator portion 22 and is capable of transmitting lithium ions.

  In particular, since the short side second separator part 24 is a non-permeable part through which lithium ions cannot permeate, when the battery 1 is charged, the short end side second of the second negative electrode part 43. Insertion of lithium ions into the short-end-side second negative electrode portion 44 facing the separator portion 24 can be reliably suppressed.

  In addition, the battery 1 includes the wound-type power generation element 10, and the second end portion of the second separator portion 23 has a short end side second separator portion 24 which is a difficult-to-transmit portion (non-transmittable portion). In the strip-shaped negative electrode active material layer 21 extending in the longitudinal direction DA, the short end-side second negative electrode portion 44 facing the short end-side second separator portion 24 occupies most of the second negative electrode portion 43. Therefore, in the first embodiment in which the second negative electrode portion 43 and the short-side-side second separator portion 24 which is a difficult to transmit portion (non-transmittable portion) face each other, the second negative electrode portion 43 is charged when the battery 1 is charged. Lithium ions inserted into the battery can be greatly reduced, and a decrease in battery capacity due to this can be sufficiently suppressed.

Next, a method for manufacturing the battery 1 according to the first embodiment will be described.
First, a paste (not shown) made by mixing and kneading positive electrode active material particles made of LiCoO ₂ and a conductive material in N-methyl-2-pyrrolidone (NMP) in which a binder is dissolved is used in the longitudinal direction. It applied to the strip-shaped aluminum foil 38 extended to DA. After application, the paste on the aluminum foil 38 was dried. The paste was similarly applied to the back side of the aluminum foil 38 and dried. Then, the positive electrode plate 30 which compressed the paste dried on both the main surfaces of the aluminum foil 38 with the roll press which is not shown in figure was produced (refer FIG. 2).

  On the other hand, a paste (not shown) made by adding negative electrode active material particles made of graphite particles and kneading them into NMP in which the binder was dissolved was applied to a strip-like copper foil 48 extending in the longitudinal direction DA. After the application, the paste on the copper foil 48 was dried. The paste was similarly applied to the back side of the copper foil 48 and dried. Then, the negative electrode plate 40 which compressed the paste dried on both the main surfaces of the copper foil 48 with the roll press which is not shown in figure was produced (refer FIG. 3).

Next, in a strip-shaped pre-process separator (not shown) made of porous polyethylene having a plurality of through holes as a whole and extending in the longitudinal direction DA, both ends of the short direction DB are attached to a hot compression press machine (not shown). Used and heat compressed. In addition, among the both ends of the short direction DB of the separator before processing, when it was wound together with the positive electrode plate 30, the portion that did not face the positive electrode active material layer 31 was thermally compressed.
This melts the polyethylene in the heat-compressed portion, completely fills the through-hole in that portion, and makes the short end side second separator portion 24 and the third separator portion 27 of the non-permeable portion incapable of transmitting lithium ions. The separator 20 having the short-side third separator part 28 and the long third non-permeable part 29B of the long-end side third separator part 29 is completed.

  The power generation element 10 is formed by winding the separator 20 between the positive electrode plate 30 and the negative electrode plate 40 manufactured as described above. The positive electrode active material layer 31 of the positive electrode plate 30 is opposed to the first negative electrode portion 42 of the negative electrode active material layer 41 of the negative electrode plate 40 via the separator 20 (first separator portion 22). The separator 20, the negative electrode plate 40, and the separator so that the short end side second separator portion 24 of the second separator portion 23 faces the short end side second negative electrode portion 44 of the second negative electrode portion 43. 20 and the positive electrode plate 30 are stacked in order.

  Thereafter, the positive electrode current collecting member 91 or the negative electrode current collecting member 92 is welded to the positive electrode plate 30 (aluminum foil 38) and the negative electrode plate 40 (copper foil 48), respectively, inserted into the battery case body 81, and the electrolysis described above. After injecting the liquid 60, the battery case body 81 is sealed with a sealing lid 82 by welding. Thus, the battery 1 is completed (see FIG. 1).

(Modification 1)
Next, the battery 101 according to the first modification of the present invention will be described with reference to FIGS.
This battery 101 is different from the battery 1 according to Embodiment 1 described above in that it has a stacked power generation element in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked via separators. The rest is the same.
Therefore, the description will be focused on differences from the battery 1 according to the first embodiment, and description of similar parts will be omitted or simplified. In addition, about the same part, the same effect is produced. In addition, the same contents are described with the same numbers.

  The battery 101 includes the same electrolyte solution 60 as in the first embodiment, each including a positive electrode plate 130, a negative electrode plate 140, and a separator 120 each having a rectangular plate shape. This is a lithium ion secondary battery forming a stacked power generation element 110 that is alternately stacked (see FIG. 6). As shown in FIG. 6, the battery 101 includes the power generation element 110 accommodated in a battery case 80 similar to that of the first embodiment.

  Among these, the power generation element 110 is a stacked type in which the positive electrode plates 130 and the negative electrode plates 140 are alternately stacked via the rectangular plate-shaped separators 120 (see FIG. 6). The positive electrode plate 130 and the negative electrode plate 140 of the power generation element 110 are respectively joined to a plate-like positive electrode current collector 91 or negative electrode current collector 92 bent in a crank shape (see FIG. 6).

Further, as shown in the perspective view of FIG. 7, the positive electrode plate 130 is a rectangular plate-shaped aluminum foil 138 and two positive electrode active material layers respectively disposed on both main surfaces of the aluminum foil 138. 131, 131.
The positive electrode active material layer 131 includes positive electrode active material particles, a conductive material, and a binder, which are not shown, as in the first embodiment.

On the other hand, as shown in the perspective view of FIG. 8, the negative electrode plate 140 is a rectangular plate-shaped copper foil 148 and two negative electrode active material layers 141 respectively disposed on both main surfaces of the copper foil 148. , 141.
Of these, the negative electrode active material layer 141 includes negative electrode active material particles and a binder, both of which are not shown, as in the first embodiment.

As shown in FIG. 8, the negative electrode active material layer 141 includes a first negative electrode portion 142 that faces the positive electrode active material layer 131 with the separator 120 interposed therebetween, and a positive electrode active material layer 131 that faces the positive electrode active material layer 131 with the separator 120 interposed therebetween. The second negative electrode part 143 is not formed.
More specifically, the area of the negative electrode active material layer 141 is larger than that of the positive electrode active material layer 131 facing the negative electrode active material layer 141. In the negative electrode active material layer 141, the first negative electrode portion 142 is located at the center of the negative electrode active material layer 141, while the second negative electrode portion 143 is located around the first negative electrode portion 142. For this reason, similarly to the battery 1 of the first embodiment, when the battery 101 is charged, it is possible to prevent metallic lithium from being deposited on the copper foil 148 located on the periphery of the negative electrode active material layer 141.

  Further, the separator 120 made of polyethylene and having a rectangular plate shape is shown in a perspective view in FIG. 9. The porous first separator portion is opposed to the first negative electrode portion 142 and can permeate lithium ions in its thickness direction DC. 122, a second separator portion 123 that faces the second negative electrode portion 143, and a third separator portion 127 that does not contact any of the positive electrode active material layer 131 and the negative electrode active material layer 141. The first separator portion 122 is located at the center of the separator 120, and the third separator portion 127 is located at the periphery of the separator 120. And the 2nd separator part 123 is arrange | positioned adjacent to each between the 1st separator part 122 and the 3rd separator part 127. FIG. Among these, the 3rd separator part 127 is made into the impermeable part made into the form which cannot permeate | transmit lithium ion thickness direction DC like the 2nd separator part 123 adjacent.

In addition, the second separator portion 123 is a difficult-to-permeate portion in which it is difficult to permeate lithium ions in the thickness direction DC as compared to the porous first separator portion 122. More specifically, as in the first embodiment, the second separator portion 123 is a non-permeable portion. For this reason, when the battery 101 is charged, lithium ions can be prevented from being inserted into the portion of the negative electrode active material layer 141 facing the second separator portion 123, that is, the second negative electrode portion 143. A decrease in battery capacity can be suppressed.
In particular, since the second separator portion 123 is a non-permeable portion that is impermeable to lithium ions, the lithium ion is reliably prevented from being inserted into the second negative electrode portion 143 when the battery 101 is charged. be able to.

Next, a method for manufacturing the battery 101 according to the first modification will be described.
First, a paste (not shown) made by adding and kneading positive electrode active material particles made of LiCoO ₂ and a conductive material into NMP in which a binder was dissolved was applied to a rectangular aluminum foil 138. After application, the paste on the aluminum foil 138 was dried. The paste was similarly applied to the back side of the aluminum foil 138 and dried. Then, the positive electrode board 130 which compressed the paste dried on both the main surfaces of the aluminum foil 138 with the roll press which is not shown in figure was produced (refer FIG. 7).

  On the other hand, a paste (not shown) made by adding negative electrode active material particles made of graphite particles and kneading them into NMP in which the binder was dissolved was applied to a rectangular copper foil 148. After application, the paste on the copper foil 148 was dried. The paste was similarly applied to the back side of the copper foil 148 and dried. Then, the negative electrode plate 140 which compressed the paste dried on both the main surfaces of the copper foil 148 with the roll press which is not shown in figure was produced (refer FIG. 8).

Subsequently, the periphery of a rectangular plate-shaped pre-processing separator (not shown) made of porous polyethylene having a plurality of through-holes as a whole was thermally compressed using a hot compression press (not shown). Note that, in the periphery of the separator before processing, when it was laminated together with the positive electrode plate 130, the portion that did not face the positive electrode active material layer 131 was thermally compressed.
As a result, the separator 120 having the second separator portion 123 and the third separator portion 127, which are made of a non-permeable portion through which lithium ions cannot permeate, is melted in the polyethylene at the heat-compressed portion to completely fill the through-hole in the portion. It ’s done.

The positive electrode plate 130 and the negative electrode plate 140 manufactured as described above are stacked with the separator 120 interposed therebetween to form the power generation element 110. The first negative electrode part 142 of the negative electrode active material layer 141 is opposed to the positive electrode active material layer 131 via the separator 120 (first separator part 122), and the second separator part 123 is the second negative electrode part. The negative electrode plate 140, the separator 120, the positive electrode plate 130, and the separator 120 are repeatedly laminated in this order so as to face 143.
Further, of the negative electrode plate 140 located on the outermost side in the stacking direction, the positive electrode active material is only formed on one main surface of the aluminum foil 138 on the outer side of the negative electrode active material layer 141 exposed to the outside via the separator 120. A positive electrode plate (not shown) on which the material layer 131 is formed is disposed and laminated. On the other hand, a negative electrode plate (not shown) in which the negative electrode active material layer 141 is formed only on one main surface of the copper foil 148 is disposed and laminated outside the separator 120 located on the other outermost side in the lamination direction.
Accordingly, in all of the plurality of negative electrode plates 140, the positive electrode active material layer 131 is disposed on the first negative electrode portion 142 of the negative electrode active material layer 141 via the separator 120 (first separator portion 122), and the second negative electrode plate Thus, the stacked power generation element 110 in which the second separator portion 123 faces the portion 143 is completed.

  Thereafter, the positive electrode collector member 91 or the negative electrode collector member 92 is welded to the positive electrode plate 130 (aluminum foil 138) and the negative electrode plate 140 (copper foil 148), respectively, inserted into the battery case body 81, and the above-described electrolysis is performed. After injecting the liquid 60, the battery case body 81 is sealed with a sealing lid 82 by welding. Thus, the battery 101 is completed (see FIG. 6).

(Embodiment 2)
A vehicle 200 according to the second embodiment is equipped with a battery pack 210 including a plurality of the batteries 1 and 101 described above. Specifically, as shown in FIG. 10, vehicle 200 is a hybrid vehicle that is driven by using engine 240, front motor 220, and 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 above-described batteries 1 and 101.

  Since the vehicle 200 according to the second embodiment is equipped with the batteries 1 and 101 that suppress the decrease in battery capacity, the vehicle 200 having a power source with stable performance can be obtained.

(Embodiment 3)
Further, the hammer drill 300 according to the third embodiment is equipped with the battery pack 310 including the batteries 1 and 101 described above, and is a battery-equipped device having the battery pack 310 and the 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 batteries 1 and 101 in which the decrease in battery capacity is suppressed, it can be a battery-equipped device having a drive energy source with stable performance.

In the above, the present invention has been described with reference to the first to third embodiments and the first modified embodiment, but the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the gist thereof. Needless to say, you can.
For example, the first separator portion 24 of the second separator portion 23 in the first embodiment is used as the second separator portion 24, and the second separator portion 123 is provided in the first embodiment as a permeation that does not have a through-hole and cannot transmit lithium ions. The impossible part. However, the short-side second separator part 24 and the second separator part 123 do not have a form in which lithium ions do not completely permeate, and may be difficult-to-permeate parts having a lower porosity than the first separator part.
In addition, the short-end-side second separator portion 24 of the first embodiment and the second separator portion 123 of the first modified embodiment are impregnated with a non-permeable portion in which a porous separator is thermally compressed to completely close a through hole. did. However, for example, a lithium ion is applied to a portion where a pore is completely filled by applying a solvent to dissolve the separator, a portion where a resin-containing solution is applied and a hole is plugged, and a porous separator. It is good also as a site | part formed by carrying | supporting, adhere | attaching (bonding), sticking, or apply | coating the member which consists of a material which cannot permeate | transmit.
Furthermore, in Embodiment 1, the short end side second separator part 24 of the first separator part 23 is the non-transmissible part. For example, the long end side second second together with the short end side second separator part 24 is used. The separator portion 25 may also be a non-transmissive portion. In this case, when the battery is charged, the region of the second negative electrode portion 43 into which lithium ions are inserted can be eliminated.

1,101 battery (lithium ion secondary battery)
10,110 Power generation element (winding power generation element)
20, 120 Separator 22, 122 First separator part 23, 123 Second separator part 24 Short end side second separator part 30, 130 Positive electrode plate 31, 131 Positive electrode active material layer 38, 138 Aluminum foil (positive electrode current collector plate) )
40, 140 Negative electrode plate 41, 141 Negative electrode active material layer 42, 142 First negative electrode portion 43, 143 Second negative electrode portion 44 Short end side second negative electrode portion 48, 148 Copper foil (negative electrode current collector plate)
60 Electrolyte 200 Vehicle 300 Hammer drill (battery-equipped equipment)
DA Longitudinal direction DB Short direction DC Thickness direction

Claims (5)

A positive electrode current collector plate having conductivity, and a positive electrode plate having a positive electrode active material layer disposed on the positive electrode current collector plate;
A negative electrode current collector plate having conductivity, and a negative electrode plate having a negative electrode active material layer disposed on the negative electrode current collector plate;
A separator interposed between the positive electrode plate and the negative electrode plate;
A lithium ion secondary battery comprising an electrolyte solution containing lithium ions,
The negative electrode active material layer is
A first negative electrode portion facing the positive electrode active material layer via the separator;
A second negative electrode portion where the positive electrode active material layer facing through the separator does not exist, and
The separator is
A porous first separator portion facing the first negative electrode portion and capable of transmitting lithium ions in its thickness direction;
A second separator portion facing the second negative electrode portion,
At least a part of the second separator portion is
A lithium ion secondary battery formed as a difficult-to-penetrate portion in which it is difficult to transmit lithium ions in the thickness direction as compared to the first separator portion. The lithium ion secondary battery according to claim 1,
The transmission difficulty portion is
A lithium ion secondary battery which is a non-permeable portion formed by making lithium ions impermeable in its thickness direction. The lithium ion secondary battery according to claim 1 or 2,
The strip-like positive electrode plate, the negative electrode plate, and the separator, all extending in the longitudinal direction,
Wound in the longitudinal direction to form a wound power generation element,
Among the strip-like negative electrode active material layers extending in the longitudinal direction, the second negative electrode portion is
A short end side second negative electrode portion positioned on each of both ends in the short direction,
The second separator portion is
A strip-shaped short end side second separator portion located on both ends in the short direction and extending in the longitudinal direction;
The short side second separator part is:
The lithium ion secondary battery which consists of the said permeation | transmission difficult part. 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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