JP6103178B2 - Power storage device and method for manufacturing power storage device - Google Patents

Description

  The present invention relates to a power storage device and a method for manufacturing the power storage device.

  Conventionally, lithium ion secondary batteries, nickel-hydrogen secondary batteries, and the like are well known as power storage devices mounted on vehicles such as EVs (Electric Vehicles) and PHVs (Plug-in Hybrid Vehicles). In these secondary batteries, a positive electrode and a negative electrode in which an active material layer containing an active material is formed on the surface of a metal foil are wound with a separator interposed therebetween to form a wound electrode assembly. There is one in which the electrode assembly is housed in a case while being formed (for example, Patent Document 1).

  And in patent document 1, among the non-formation part in which the active material layer is not formed in a positive electrode, by providing an insulating resin film in the part facing the formation part in which the active material layer was formed in the negative electrode, The contact between the metal foil and the active material layer of the negative electrode is suppressed, and the safety as a secondary battery is enhanced.

JP 2006-302877 A

  By the way, the secondary battery has a stacked electrode assembly in which a positive electrode and a negative electrode are alternately stacked with a separator interposed therebetween, and is protruded from an edge of the electrode assembly. Some of the current collecting tabs are electrically connected to electrode terminals fixed to the case. Here, the current collecting tab group has a structure in which the current collecting tabs protruding from the edges of the positive electrode and the negative electrode overlap each other, so that the electrode terminal and the current collecting tab group include the current collecting tab group. In general, a plurality of layers of current collecting tabs to be configured are connected to electrode terminals in a state of being gathered in the stacking direction.

  For this reason, when a plurality of layers of current collecting tabs are gathered together and connected to the electrode terminals, the separator may be damaged by applying a load to the separator. In addition, the stacked electrode assembly repeatedly expands and contracts in the stacking direction of the positive electrode and the negative electrode along with charge / discharge, so that one end is fixed between the positive electrode and the negative electrode together with each current collecting tab fixed to the electrode terminal. A load is also applied to the separator interposed between the separators, which may damage the separator.

  This invention was made paying attention to the problem which exists in the said prior art, The objective is to provide the electrical storage apparatus which can suppress that a separator breaks, and the manufacturing method of an electrical storage apparatus.

In order to solve the above-mentioned problem, the invention according to claim 1 is a stacked electrode assembly in which a positive electrode and a negative electrode in which an active material layer is formed on the surface of a metal foil are stacked in layers with a separator interposed therebetween. A power storage device comprising a solid body and a case in which the electrode assembly is accommodated and an electrode terminal is fixed, and at least one edge portion of the positive electrode edge portion extends along the edge portion. The active material layer is not formed, and a positive electrode non-formation part electrically connected to the electrode terminal is provided, and at least a part of the positive electrode non-formation part has the separator interposed therebetween In the state, the negative electrode is opposed to the negative electrode forming portion where the active material layer is formed in the negative electrode, and at least a portion sandwiched between the non-positive electrode forming portion and the negative electrode forming portion in the separator has an insulating property. Covered with resin or A reinforcing portion impregnated with a conductive resin is formed, and the insulating resin is polytetrafluoroethylene, and the thickness of the reinforcing portion is the thickness of the active material layer in the positive electrode and the separator in the separator. and summarized in that the reinforcing section is a sum and same thickness of the portion not provided.

  According to this, in the separator, at least a portion of the positive electrode between which the active material layer is not formed and a portion of the negative electrode sandwiched between the negative electrode forming portion where the active material layer is formed is insulated. A reinforcing portion covered with a conductive resin or impregnated with an insulating resin is formed. For this reason, in the separator, the strength of the portion sandwiched between the positive electrode non-forming part and the negative electrode forming part is improved, and the load applied when the positive electrode non-forming part and the electrode terminal are connected, and the electrode assembly accompanying charge / discharge It can suppress that a separator breaks with the load provided by expansion | swelling and contraction.

Moreover, the insulating resin which comprises a reinforcement part is polytetrafluoroethylene with high heat resistance. Therefore, in the separator, the heat resistance of the portion sandwiched between the positive electrode non-forming portion and the negative electrode forming portion can be increased, and for example, it is possible to suppress the separator from shrinking and damaging as the temperature of the power storage device increases.
The thickness of the reinforcing portion has a thickness of the active material layer in the positive electrode, the sum and the same thickness is the portion where the reinforcing part is not provided in the separator. According to this, it can suppress that a clearance gap produces between a positive electrode non-formation part and a negative electrode formation part, and a separator by arrange | positioning a reinforcement part between a positive electrode non-formation part and a negative electrode formation part. Therefore, when the separator is sandwiched between the positive electrode non-forming part and the negative electrode forming part, for example, deformation such as shrinkage due to the temperature rise of the power storage device is suppressed, and thus the separator can be prevented from being damaged.

The invention according to claim 2, in the electric storage device according to claim 1, wherein the edge where the reinforcing part is formed in the separator extends along the edge where the positive electrode non-formation portion is provided bent And from the bent portion toward the edge on the opposite side of the edge of the positive electrode where the positive electrode non-formation part is provided, and the positive electrode non-formation part and the negative electrode formation part And a folded portion sandwiched between the two. According to this, the strength of the separator can be further improved by the folded portion extending from the bent portion, and the separator can be prevented from being damaged.

According to a third aspect of the present invention, in the power storage device according to the first or second aspect , the positive electrode non-forming portion includes a tab portion that is electrically connected to the electrode terminal, and the reinforcing portion is the It is provided in the part except the part which overlaps with the said tab part among separators.

According to this, since the reinforcement part is not provided in the part which overlaps with a tab part among separators, it can suppress that it becomes difficult to connect a tab part and an electrode terminal.
According to a fourth aspect of the present invention, in the power storage device according to any one of the first to third aspects, the separator is formed by uniaxially stretching an insulating resin material, and the electrode assembly The separator is laminated in a state where the extending direction thereof coincides with the extending direction of the edge portion where the positive electrode non-forming portion is provided.
According to a fifth aspect of the present invention, in the power storage device according to any one of the first to fourth aspects, the power storage device is a secondary battery. According to this, it can suppress that a separator breaks as a secondary battery.

Invention of Claim 6 is a manufacturing method of the electrical storage apparatus of any one of Claims 1-5 , Comprising: The said positive electrode non-formation part in the said positive electrode, and the said negative electrode formation part in the said negative electrode The gist of the invention includes a lamination step of alternately laminating the positive electrode and the negative electrode in a state where the reinforcing portion provided in the separator is disposed therebetween.

  According to this, since the positive electrode and the negative electrode are alternately laminated with the reinforcing portion provided in the separator disposed between the positive electrode non-forming portion and the negative electrode forming portion, the positive electrode non-forming portion and the electrode terminal It is possible to prevent the separator from being damaged by a load applied when connecting the electrodes and a load applied by expansion and contraction of the electrode assembly accompanying charge / discharge.

  According to the present invention, the separator can be prevented from being damaged.

Sectional drawing which shows a lithium ion secondary battery typically. The perspective view which shows an electrode assembly typically. The front view which shows a separator typically. Sectional drawing which expands and shows an electrode assembly typically. The perspective view which shows typically the separator in another embodiment.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, for example, a lithium ion secondary battery (hereinafter referred to as “secondary battery”) 10 as a power storage device mounted on a vehicle such as a passenger vehicle or an industrial vehicle includes a case 11 and an electrode assembly 12. Contained.

  The case 11 includes a bottomed rectangular box-shaped main body member 11a that houses the electrode assembly 12, and a rectangular plate-shaped lid member 11b that closes an opening of the main body member 11a. The main body member 11a and the lid member 11b are made of a metal such as stainless steel or aluminum.

  The case 11 is filled with a nonaqueous electrolytic solution 13 as an electrolyte. A positive electrode terminal 15 and a negative electrode terminal 16 are fixed to a lid member 11b which is one of the walls constituting the case 11, and protrudes outward. The electrode assembly 12 is housed in the case 11 in a state of being covered with an insulating resin sheet 14.

  As shown in FIG. 2, the electrode assembly 12 includes a positive electrode sheet 18 as a positive electrode (electrode), a negative electrode sheet 19 as a negative electrode (electrode) having a polarity different from that of the positive electrode sheet 18, and the positive electrode sheet 18 and the negative electrode sheet 19. And a rectangular sheet-like separator 20 that insulates between the two. The electrode assembly 12 is a stacked electrode assembly in which a plurality of positive electrode sheets 18 and a plurality of negative electrode sheets 19 are alternately stacked with separators 20 interposed therebetween, and these are stacked in layers. . In the following description, the “stacking direction” means the stacking direction of the positive electrode sheet 18 and the negative electrode sheet 19 in the electrode assembly 12 (indicated by an arrow Y).

  The negative electrode sheet 19 is formed by applying a negative electrode metal foil (copper foil in this embodiment) 21 and an active material mixture containing a negative electrode active material on both surfaces of the negative electrode metal foil 21 and drying the negative electrode active material layer. 22. In the negative electrode metal foil 21, the negative electrode active material layer 22 has a constant width (full width in this embodiment) from the first negative electrode edge 19a provided on the terminals 15 and 16 side to the second negative electrode edge 19b on the opposite side. Each negative electrode edge 19a, 19b is formed over the entire width from one edge located at both ends in the extending direction to the other edge. Hereinafter, in the negative electrode sheet 19, a portion where the negative electrode active material layer 22 is formed is referred to as a negative electrode forming portion 22 a.

  A negative electrode non-formation portion 23, which is a portion where the negative electrode active material layer 22 is not formed, protrudes from the first negative electrode edge portion 19 a of the negative electrode metal foil 21 as a negative electrode current collecting tab 24. On the surface of the negative electrode metal foil 21, between the second negative electrode edge portion 19 b and the negative electrode current collecting tab 24, and at the base end portion of the negative electrode current collecting tab 24, the negative electrode forming portion 22 a and the negative electrode non-forming portion 23 The negative electrode boundary part 19c which is a boundary is provided.

  The negative electrode current collecting tab 24 is formed in the same shape at the same position in each negative electrode sheet 19 constituting the electrode assembly 12. For this reason, as shown in FIG. 1, a negative electrode current collecting tab group 24a in which a plurality of negative electrode current collecting tabs 24 are layered is projected on one edge portion 12a of the edge portions of the electrode assembly 12. Yes. The negative electrode current collecting tab group 24a is electrically connected to the negative electrode terminal 16 by welding or the like in a state where a plurality (a plurality of layers) of negative electrode current collecting tabs 24 (negative electrode non-forming portions 23) are gathered in the stacking direction. The

  The positive electrode sheet 18 includes a positive electrode metal foil 25 and a positive electrode active material layer 26 formed by applying an active material mixture containing a positive electrode active material to both surfaces of the positive electrode metal foil 25 and drying the mixture. In the positive electrode metal foil 25, the positive electrode active material layer 26 has a constant width from the second positive electrode edge 18b opposite to the first positive electrode edge 18a provided on the terminals 15 and 16 side, and the positive electrode edge 18a, It is formed over the entire width from one edge located at both ends in the direction in which 18b extends to the other edge. Hereinafter, in the positive electrode sheet 18, a portion where the positive electrode active material layer 26 is formed is referred to as a positive electrode forming portion 26a. The thickness of the positive electrode metal foil 25 is, for example, 15 μm to 20 μm, and the thickness of the positive electrode active material layer 26 is, for example, 30 μm to 45 μm.

  Further, the positive electrode metal foil 25 has a constant width from the first positive electrode edge portion 18a toward the second positive electrode edge portion 18b and from one edge portion located at both ends in the direction in which each positive electrode edge portion 18a, 18b extends to the other. A positive electrode non-formation portion 27, which is a portion where the positive electrode active material layer 26 is not formed, is provided over the entire width up to the edge portion. In other words, a positive electrode boundary portion 18 c that is a boundary between the positive electrode forming portion 26 a and the positive electrode non-forming portion 27 is provided between the first positive electrode edge portion 18 a and the second positive electrode edge portion 18 b. A positive electrode current collecting tab 28 protrudes from the first positive electrode edge 18 a of the positive electrode sheet 18. The positive electrode current collecting tab 28 is a part of the positive electrode metal foil 25 constituting the positive electrode non-forming part 27.

  The positive electrode current collecting tab 28 is formed in the same position and in the same shape in each positive electrode sheet 18 constituting the electrode assembly 12. The positive electrode current collecting tab 28 is provided at a position that does not overlap the negative electrode current collecting tab 24 when the positive electrode sheet 18 and the negative electrode sheet 19 are laminated. Therefore, as shown in FIG. 1, a positive electrode current collecting tab group in which a plurality of positive electrode current collecting tabs 28 are layered on the edge 12a of the electrode assembly 12 in a portion different from the negative electrode current collecting tab group 24a. 28a is projected. A positive electrode terminal 15 is electrically connected to the positive electrode current collecting tab group 28a by welding or the like in a state where a plurality (multiple layers) of positive electrode current collecting tabs 28 (positive electrode non-forming portions 27) are gathered in the stacking direction. The

  As shown in FIG. 3, when viewed from the stacking direction, the positive electrode metal foil 25 excluding the positive electrode current collecting tab 28 is smaller than the negative electrode metal foil 21 excluding the negative electrode current collecting tab 24 and the positive electrode sheet 18. The positive electrode forming portion 26 a is smaller than the negative electrode forming portion 22 a of the negative electrode sheet 19. And when it sees from the lamination direction, the 1st positive electrode edge part 18a and the 1st negative electrode edge part 19a have overlapped. When viewed from the stacking direction, the negative electrode metal foil 21 excluding the negative electrode current collecting tab 24 and the positive electrode metal foil 25 excluding the positive electrode current collecting tab 28 are smaller than the separator 20.

  For this reason, in the electrode assembly 12, the positive electrode metal foil 25 excluding the positive electrode current collecting tab 28 entirely overlaps the negative electrode forming portion 22 a of the negative electrode sheet 19 when viewed from the stacking direction. That is, the portion of the positive electrode non-forming portion 27 excluding the positive electrode current collecting tab 28 becomes a facing portion 27 a that faces the negative electrode active material layer 22 of the negative electrode sheet 19 with the separator 20 interposed therebetween.

Next, the separator 20 will be described in detail.
As shown in FIG. 3, the separator 20 is a sheet-like porous film (porous body) having fine pores in which an insulating resin material is uniaxially stretched. In the electrode assembly 12, the separator 20 is laminated in a state where the extending direction thereof coincides with the extending direction of the edge portions 18 a and 19 a. Separator 20 of this embodiment is formed, for example from polyethylene, and the melting point is 100 ° C-130 ° C, for example. The thickness of the separator 20 is, for example, 15 μm to 20 μm.

  The separator 20 extends along the first edge 20a on the terminals 15 and 16 side from the third edge 20d located at both ends in the extending direction of the first edge 20a to the other fourth edge 20e. A resin composite portion 30 is provided as a reinforcing portion in which the separator 20 is impregnated with the insulating resin over the entire width. In other words, the separator 20 is formed with the resin composite portion 30 having a constant width from the second edge portion 20b opposite to the first edge portion 20a and the entire width from the third edge portion 20d to the fourth edge portion 20e. Absent. For this reason, between each edge part 20a and 20b, the separator boundary part 20c of the resin composite part 30 and the part which is not impregnated with PTFE fiber is provided.

  As shown in FIGS. 3 and 4, the portion of the separator 20 where the resin composite portion 30 is formed is the entire portion sandwiched between the positive electrode non-forming portion 27 (opposing portion 27 a) and the negative electrode forming portion 22 a. In addition, the positive electrode boundary portion 18c and the separator boundary portion 20c overlap each other when viewed from the stacking direction. The thickness of the resin composite portion 30 is the same (or substantially the same) as the thickness of the separator 20 where the resin composite portion 30 is not formed, and is greater than the sum of the thickness and the thickness of the positive electrode active material layer 26. thin.

  The insulating resin used for the resin composite portion 30 is a fine fibrous particle of polytetrafluoroethylene (PTFE) having an average particle diameter of, for example, 0.15 μm to 0.35 μm (hereinafter referred to as “PTFE fiber”). It is. The “average particle size” in this specification means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method. The melting point of PTFE is, for example, 327 ° C. to 340 ° C., which is higher than the melting point of the resin material forming the separator 20.

  Further, in the resin composite portion 30, PTFE fibers enter the pores of the separator 20, and the PTFE fibers form a three-dimensional structure in which the PTFE fibers are entangled with each other in the pores of the separator 20. And in the separator 20, the void | hole of the part in which the resin composite part 30 was formed is filled with the PTFE fiber, and is obstruct | occluded.

  For this reason, in the resin composite part 30, since the resin material which comprises the separator 20, and PTFE (PTFE fiber) form the composite material, the mechanical strength in this resin composite part 30 is resin in the separator 20. It is higher than the mechanical strength of the part where the composite part 30 is not formed.

Next, the effect | action of the secondary battery 10 of this embodiment is demonstrated.
As shown in FIG. 4, in the separator 20, the resin composite portion 30 extends from the third edge portion 20 d to the fourth portion between the positive electrode non-forming portion 27 where the positive metal foil 25 is exposed and the negative electrode forming portion 22 a. It extends to the edge 20e. Thereby, in the separator 20, the intensity | strength of the part pinched by the positive electrode non-formation part 27 and the negative electrode formation part 22a can be improved.

  For this reason, in order to connect the positive electrode current collecting tab group 28a and the positive electrode terminal 15, the separator 20 is caused by a load when collecting a plurality of (multiple layers) positive electrode current collecting tabs 28 in the stacking direction (indicated by the arrow Y). Among these, it can suppress suitably that the part pinched between the positive electrode non-formation part 27 and the negative electrode formation part 22a is damaged. The same applies to the connection between the negative electrode current collecting tab group 24 a and the negative electrode terminal 16.

  Moreover, in this embodiment, it can suppress that the separator 20 is damaged by the load provided with the negative electrode current collection tab 24 or the positive electrode current collection tab 28 by expansion and contraction of the electrode assembly 12 accompanying charging / discharging. In particular, since the resin composite portion 30 of the present embodiment is formed in a size that covers the entire facing portion 27a, the positive electrode non-forming portion 27 and the negative electrode active material layer 22 are brought into contact with each other due to damage of the separator 20. Can be further suppressed.

  These are the capacity maintenance ratios after repeated charging / discharging a predetermined number of times for the secondary battery 10 of the present invention and the secondary battery (comparative example) using the separator without the resin composite portion 30. This is supported by evaluating the incidence of short circuit after the vibration test.

  Specifically, after the full charge and the discharge at a constant current of 0.2 C were repeated 10 times, the capacity retention rates of the secondary battery 10 of the present invention and the secondary battery of the comparative example were evaluated. The capacity maintenance rate is defined as 100% of the capacity (Ah) at the first full charge after the secondary battery is manufactured. As a result, in the secondary battery 10 of the present invention, the capacity retention rate after 10 times of charge and discharge was about 100%, whereas in the comparative example, it was only about 93%.

The vibration test is stipulated in “JIS1601 Type 2A” and is a 3G condition for in-vehicle use. For a forklift without a suspension, a vibration of 33 Hz and 29.4 m / s ² is applied for up and down 4 hours and left and right 2 hours. And after 2 hours before and after, the incidence of short circuit was evaluated. As a result, in the secondary battery 10 of the present invention, the occurrence rate of short circuit was 0%, whereas in the comparative example, the occurrence rate of short circuit was about 5.3%.

  From these results, in the comparative example, when the current collecting tab groups 24a and 28a are connected to the terminals 15 and 16, respectively, due to the expansion and contraction of the electrode assembly accompanying charging / discharging and the vibration applied to the secondary battery. It is considered that a minute breakage of the separator 20 caused in the above becomes obvious or the separator 20 is newly broken, resulting in a decrease in capacity retention rate or a short circuit.

  On the other hand, in the secondary battery 10 of the present embodiment, since the capacity retention rate is not reduced or a short circuit does not occur, the current collecting tab groups 24a and 28a are connected to the terminals 15 and 16, respectively. It was confirmed that the separator 20 was prevented from being damaged by the vibration applied to the secondary battery 10.

  Further, in the present embodiment, the pores of the separator 20 in the resin composite part 30 are closed with PTFE fibers, and the strength of the resin composite part 30 is further improved. Note that, in the portion of the separator 20 that is sandwiched between the non-positive electrode forming portion 27 and the negative electrode forming portion 22a, the positive electrode active material layer 26 and the negative electrode active material layer 22 do not face each other, so that lithium ions do not pass through. Problems such as precipitation of metallic lithium due to the occurrence of the above are unlikely to occur.

  The resin composite part 30 is made of polytetrafluoroethylene as a heat-resistant resin material. For this reason, the heat resistance of the part pinched | interposed into the positive electrode non-formation part 27 and the negative electrode formation part 22a among the separators 20 can be improved.

  Here, as shown in FIG. 4, in addition to the thickness of the separator 20, the thickness of the positive electrode active material layer 26 is between the positive electrode non-formation portion 27 (positive metal foil 25) and the negative electrode active material layer 22. There is only enough space. For this reason, between the positive electrode non-formation part 27 and the negative electrode formation part 22a, the separator 20 is not clamped like the positive electrode formation part 26a and the negative electrode formation part 22a. And as mentioned above, the separator 20 of this embodiment is manufactured by uniaxial stretching.

  For this reason, in the separator 20 that does not have the resin composite portion 30, the separator 20 is contracted (curled) in the stretching direction as the temperature rises between the positive electrode non-forming portion 27 and the negative electrode forming portion 22a. There is a possibility that the insulating property may be lowered due to partial disposition between the non-formed part 27 and the negative electrode forming part 22a.

  On the other hand, in the separator 20 of the present embodiment, the secondary battery is provided by providing the resin composite portion 30 using the PTFE fiber having high heat resistance, as compared with the configuration in which the resin composite portion 30 is not provided. It is possible to suppress a decrease in insulation due to shrinkage (curl) associated with a temperature increase of 10.

Next, a method for manufacturing the secondary battery 10 will be described.
First, the strip-shaped separator 20 is cut into a rectangular sheet shape, and the average particle diameter is, for example, 0. 0 at a portion disposed between the positive electrode non-forming portion 27 of the positive electrode sheet 18 and the negative electrode forming portion 22a of the negative electrode sheet 19. A dispersion liquid in which PTFE fibers of 15 μm to 0.35 μm are dispersed in a predetermined solvent (for example, water) so as to be 60% by weight is impregnated. Thereafter, the separator 20 impregnated with the dispersion of PTFE fibers is dried to form a three-dimensional structure in the PTFE fibers that have entered the pores of the separator 20, and the pores are closed with the PTFE fibers. The composite unit 30 is completed.

  Next, the separator 20, the positive electrode sheet 18 prepared in a separate process, and the negative electrode sheet 19 are stacked to form the electrode assembly 12 (lamination process). At this time, the resin composite part 30 provided in the separator 20 is disposed between the positive electrode non-forming part 27 in the positive electrode sheet 18 and the negative electrode forming part 22a of the negative electrode sheet 19, and the positive electrode sheet 18 and the negative electrode sheet 19 are arranged. Are alternately stacked.

  Thereafter, the electrode assembly 12 covered with the resin sheet 14 is accommodated in the case 11, and the current collecting tab groups 24 a and 28 a are connected to the terminals 15 and 16, respectively, and further filled with the nonaqueous electrolytic solution 13 to be secondary. The battery 10 is completed. At this time, in order to connect the positive electrode current collecting tab group 28 a and the positive electrode terminal 15, the positive electrode non-forming portion 27 and the negative electrode forming portion of the separator 20 are gathered by a force gathering the positive electrode current collecting tabs 28 in the stacking direction. It can suppress suitably that the part pinched | interposed between 22a is damaged. The same applies to the negative electrode current collecting tab group 24a side.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) In the separator 20, a resin composite portion 30 is formed at a portion sandwiched between the positive electrode non-forming portion 27 and the negative electrode forming portion 22 a. For this reason, the strength of the portion sandwiched between the positive electrode non-forming part 27 and the negative electrode forming part 22a in the separator 20 is improved, and the load applied when connecting the current collecting tab groups 24a and 28a and the terminals 15 and 16 respectively. The separator 20 can be prevented from being damaged by the load applied by the expansion and contraction of the electrode assembly 12 due to charge / discharge.

(2) Particularly, in the present embodiment, the entire facing portion 27 a is covered by the resin composite portion 30. Therefore, it can suppress that the separator 20 breaks more.
(3) The resin composite part 30 is formed by impregnating PTFE fibers having high heat resistance. Therefore, in the separator 20, the heat resistance of the portion sandwiched between the positive electrode non-forming portion 27 and the negative electrode forming portion 22 a can be increased, and for example, the separator 20 can be prevented from being damaged due to shrinkage accompanying the temperature rise of the secondary battery 10.

(4) As the secondary battery 10, it can suppress that the separator 20 breaks with charging / discharging.
(5) In the secondary battery 10 (electrode assembly 12), the positive electrode sheet 18 and the negative electrode sheet 19 are alternately arranged in a state where the resin composite part 30 is disposed between the positive electrode non-forming part 27 and the negative electrode forming part 22a. It is formed by stacking. For this reason, the separator 20 is damaged by a load applied when the current collecting tab groups 24a and 28a are connected to the terminals 15 and 16, respectively, or a load applied by expansion and contraction of the electrode assembly 12 due to charge / discharge. This can be suppressed.

The embodiment is not limited to the above, and may be embodied as follows, for example.
As shown in FIG. 5, the edge portion 20 a where the resin composite portion 30 is formed in the separator 20 includes a bent portion 40 extending along the first positive electrode edge portion 18 a provided with the positive electrode non-forming portion 27, A folded portion 41 extending from the bent portion 40 toward the second positive electrode edge portion 18b opposite to the first positive electrode edge portion 18a in the positive electrode sheet 18 and sandwiched between the positive electrode non-forming portion 27 and the negative electrode forming portion 22a. You may have. In this case, the resin composite portion 30 only needs to be formed at least in the folded portion 41, and may be formed in a portion overlapping the folded portion 41 including the folded portion 41 in the separator 20 when viewed from the stacking direction. Good. According to this, the strength of the separator 20 can be further improved by the folded portion 41 extending from the bent portion 40, and the separator 20 can be prevented from being damaged due to charge / discharge.

  The reinforcing part may be formed by applying an insulating resin to the surface of the separator 20 so as to cover the separator 20 with the insulating resin. The reinforcing portion may impregnate the separator 20 with an insulating resin.

  When the reinforcing part is formed by covering the surface of the separator 20 with an insulating resin, the thickness of the resin composite part 30 is the same as the thickness of the positive electrode active material layer 26 in the positive electrode sheet 18 and the resin composite part 30 in the separator 20. It may be the same as or substantially the same as the sum of the thicknesses of the portions not formed. According to this, by arranging the resin composite part 30 between the positive electrode non-forming part 27 and the negative electrode forming part 22a, a gap is generated between the positive electrode non-forming part 27 and the negative electrode forming part 22a and the separator 20. Can be suppressed. Therefore, when the separator 20 is sandwiched between the positive electrode non-forming portion 27 and the negative electrode forming portion 22a, for example, deformation such as shrinkage due to the temperature rise of the secondary battery 10 is suppressed, and thus the separator 20 is damaged. Can be suppressed.

  The resin composite portion 30 may be provided in a portion of the separator 20 excluding a portion overlapping with the positive electrode current collecting tab 28. According to this, since the resin composite part 30 is not provided in the part which overlaps with the positive electrode current collection tab 28, it becomes difficult to connect the positive electrode current collection tab 28 and the positive electrode terminal 15 with the resin composite part 30 with high intensity | strength. This can be suppressed. In particular, in the above embodiment, since PTFE having high heat resistance is used, it is possible to suitably suppress, for example, difficulty in connection by welding.

  The resin composite part 30 does not need to be formed on the entire portion of the separator 20 sandwiched between the positive electrode non-forming part 27 (opposing part 27a) and the negative electrode forming part 22a. That is, the resin composite part 30 should just be formed in a part of part which is pinched | interposed between the positive electrode non-formation part 27 and the negative electrode formation part 22a among the separators 20 at least.

(Circle) the separator boundary part 20c and the positive electrode boundary part 18c do not need to overlap.
The resin composite part 30 may increase the coating amount or impregnation amount per unit area of the insulating resin from the second edge part 20b toward the first edge part 20a. According to this, strength can be improved, so that it is the 1st edge 20a side.

The separator 20 may be cut into a rectangular sheet after the resin composite portion 30 is provided on the roll-shaped separator 20.
(Circle) you may change the insulating resin which comprises the resin composite part 30. FIG. Examples of the insulating resin that can be used for the resin composite portion 30 include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, and vinylidene fluoride-trichloroethylene chloride (CTFE) copolymer. And fluorine-based polymers such as vinylidene fluoride-hexafluoropropylene fluororubber, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene fluororubber, and vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether fluororubber. In addition to the fluorine-based resin, polyacryl, polyolefin, polyamide, polyimide, polyamideimide, epoxy resin, bakelite, or the like may be used. Specific examples include polypropylene oxide, polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, styrene-butadiene rubber, propylene-butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, and various latexes. These insulating resins may be used alone or in combination of two or more.

O The insulating resin constituting the resin composite portion 30 may not be a resin material with high heat resistance.
○ The resin material forming the separator 20 may be changed. For example, polypropylene or polyamideimide (PAI) may be used, or a multilayer structure separator 20 in which a plurality of porous films (sheets) formed from different resin materials may be stacked.

○ The metal constituting the negative electrode metal foil 21 and the positive electrode metal foil 25 may be changed.
(Circle) the positive electrode boundary part 18c may be provided on the positive electrode current collection tab 28 in the surface of the positive electrode metal foil 25, and may correspond with the 1st positive electrode edge part 18a.

  The negative electrode boundary portion 19c may be provided on the negative electrode current collecting tab 24 on the surface of the negative electrode metal foil 21, and is provided between the first negative electrode edge portion 19a and the second negative electrode edge portion 19b. Also good.

  The electrode assembly 12 may be a wound-type electrode assembly in which the positive electrode sheet 18 and the negative electrode sheet 19 are formed in a band shape and wound with a band-shaped separator 20 interposed therebetween.

The positive electrode sheet 18 and the negative electrode sheet 19 may be formed by applying an active material on one side.
O You may actualize in electrical storage apparatuses, such as a nickel hydride secondary battery and an electric double layer capacitor.

  O You may actualize in the electrical storage apparatus used other than a vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Lithium ion secondary battery (secondary battery, electrical storage apparatus), 11 ... Case, 12 ... Electrode assembly, 15 ... Positive electrode terminal (electrode terminal), 16 ... Negative electrode terminal (electrode terminal), 18 ... Positive electrode sheet (positive electrode) ), 18a: first positive electrode edge (edge), 18b: second positive electrode edge (edge), 19 ... negative electrode sheet (negative electrode), 20 ... separator, 20d ... third edge (edge), 20e ... 4th edge part (edge part), 21 ... Negative electrode metal foil (metal foil), 22 ... Negative electrode active material layer, 22a ... Negative electrode formation part, 24 ... Negative electrode current collection tab (tab part), 25 ... Positive electrode metal foil ( (Metal foil), 26 ... positive electrode active material layer, 27 ... positive electrode non-forming part, 28 ... positive electrode current collecting tab (tab part), 30 ... resin composite part (reinforcing part), 40 ... bent part, 41 ... folded part.

Claims (6)

A stacked electrode assembly in which a positive electrode and a negative electrode having an active material layer formed on the surface of a metal foil are layered with a separator interposed therebetween, and the electrode assembly is accommodated and an electrode terminal is fixed A power storage device comprising a case,
At least one of the edges of the positive electrode is provided with a positive electrode non-forming portion that is not formed with the active material layer and is electrically connected to the electrode terminal along the edge. And at least part of the positive electrode non-forming portion is opposed to the negative electrode forming portion where the active material layer is formed in the negative electrode with the separator interposed therebetween,
In the separator, at least a portion sandwiched between the positive electrode non-forming portion and the negative electrode forming portion is formed with a reinforcing portion covered with an insulating resin or impregnated with the insulating resin. ,
The insulating resin is polytetrafluoroethylene,
The thickness of the reinforcing portion is a power storage device wherein said the thickness of the active material layer in the positive electrode, the reinforcing portion in the separator is a sum and same thickness of the portion not provided. In the separator, the edge where the reinforcing portion is formed is a bent portion extending along the edge where the positive electrode non-forming portion is provided, and the positive electrode is not formed out of the edge of the positive electrode from the bent portion. 2. The power storage device according to claim 1, wherein the power storage device includes a folded portion that extends toward an edge opposite to the edge provided with the portion and is sandwiched between the positive electrode non-forming portion and the negative electrode forming portion. . The positive electrode non-forming portion includes a tab portion that is electrically connected to the electrode terminal,
The reinforcing portion is a power storage device according to claim 1 or 2 is provided in a portion excluding the part overlapping with the tab portion of the separator.   The separator is formed by uniaxially stretching an insulating resin material,
  The said separator in the said electrode assembly is laminated | stacked in the state in which the extending | stretching direction was in agreement with the extending direction of the edge part in which the said positive electrode non-formation part was provided. Power storage device. The power storage device according to any one of claims 1 to 4 , wherein the power storage device is a secondary battery. It is a manufacturing method of the electrical storage device according to any one of claims 1 to 5 ,
A lamination step of alternately laminating the positive electrode and the negative electrode in a state where the reinforcing portion provided in the separator is disposed between the positive electrode non-formation part in the positive electrode and the negative electrode formation part in the negative electrode. A method for manufacturing a power storage device, comprising: