JP2019117738A - Power storage device and method of manufacturing power storage device - Google Patents

Abstract

To provide a power storage device in which a negative electrode tub group and a case can be easily insulated from each other, and a method of manufacturing a power storage device.SOLUTION: A secondary battery 10 comprises an insulation cover 50 that has: a first portion 51 arranged between a lid 14 and a negative electrode conductive member 20b, and insulating the lid 14 and the negative electrode conductive member 20b from each other; and a third portion 53 arranged between a negative electrode tab group 16 and inner surfaces of a case body 13 on the lamination direction- other end side of a positive electrode 21 and a negative electrode 22, and insulating the negative electrode tab group 16 and the case body 13 from each other. The negative tab group 16 comprises an insulation layer 60 in a first end surface A1 positioned on one lamination direction-end side in a collection foil part 17a. The insulation layer 60 includes: a first layer 61 in which a first particle P1 made of a ceramic and a flat-shaped second particle P2 made of copper are mixed, and which is opposite to an inner surface of the case body 13; and a second layer 62 in which the second particle P2 is present, and which is positioned between the first layer 61 and the first end surface A1.SELECTED DRAWING: Figure 2

Description

  The present invention includes a negative electrode tab group in which a negative electrode tab protruding from a negative electrode is stacked, and the negative electrode tab group is a foil collection portion in which a plurality of negative electrode tabs are gathered at one end side of the positive electrode and the negative electrode in the stacking direction. And a method of manufacturing the power storage device, which is curved from one end side to the other end side in the stacking direction.

  Conventionally, in vehicles such as EV (Electric Vehicle) and PHV (Plug in Hybrid Vehicle), a lithium ion secondary battery, a nickel hydrogen secondary battery, etc. are mounted as a storage device for storing power supplied to a traveling motor. There is. The secondary battery includes an electrode assembly in which sheet-like positive and negative electrodes are laminated in an insulated state, and a case for accommodating the electrode assembly. The positive electrode has a positive electrode metal foil made of aluminum and a positive electrode active material layer present on at least one surface of the positive electrode metal foil. The positive electrode has a positive electrode tab shaped to protrude from a part of the edge. The positive electrode tab does not have a positive electrode active material layer, and is formed of a positive electrode metal foil itself. The negative electrode has a negative electrode metal foil made of copper or a copper alloy, and a negative electrode active material layer present on at least one side of the negative electrode metal foil. The negative electrode has a negative electrode tab shaped to protrude from a part of the edge. The negative electrode tab does not have the negative electrode active material layer, and is formed of the negative electrode metal foil itself.

  The electrode assembly has a positive electrode tab group in which a positive electrode tab is stacked and a negative electrode tab group in which a negative electrode tab is stacked. The positive electrode tab group and the negative electrode tab group have a foil collection portion in which a plurality of positive electrode tabs and negative electrode tabs are gathered at one end side of the positive electrode and the negative electrode in the stacking direction, and from one end side to the other end in the stacking direction It is curved towards. The case has a bottomed cylindrical case body and a lid closing the opening of the case body.

  The secondary battery disclosed in Patent Document 1 includes an electrode terminal of each polarity that exchanges electricity with the electrode assembly, and a conductive member that electrically connects a tab group of the same polarity and the electrode terminal. Each electrode terminal is fixed to a lid. Each conductive member is disposed between the lid and the tab-side end surface of the electrode assembly facing the inner surface of the lid and in which the positive electrode tab group and the negative electrode tab group are present. The electrode assembly, the lid, the electrode terminal of each polarity, the conductive member of each polarity, and the tab group of each polarity are integrated as a unit member, and the gap between the lid and the conductive member is reduced in the case body. Be housed.

  Moreover, the secondary battery disclosed in Patent Document 2 includes an insulating cover. The insulating cover has a rectangular plate-shaped first portion, a second portion extending from one end in the width direction of the first portion in the thickness direction of the first portion, and the other end in the width direction of the first portion It is a cross section U-shaped cover which has the 3rd section extended in the thickness direction of the 1st section. The insulating cover is attached from the lid side to the electrode assembly in a state of being integrated with the conductive member through the positive electrode tab group and the negative electrode tab group. The first portion is disposed between the lid and the conductive member and insulates the lid from the conductive member. The second portion is disposed between the positive electrode tab group and the negative electrode tab group and the case main body on one end side in the stacking direction, and insulates the positive electrode tab group and the negative electrode tab group from the case. The third portion is disposed between the positive electrode tab group and the negative electrode tab group and the case main body on the other end side in the stacking direction, and insulates the positive electrode tab group and the negative electrode tab group from the case.

JP, 2016-122533, A International Publication No. 2013/157433

  By the way, when the electrode assembly, the lid, the electrode terminal of each polarity, the conductive member of each polarity, and the tab group of each polarity are integrated as in Patent Document 1, insulation is performed from the lid side as in Patent Document 2. I can not attach the cover. On the negative electrode side, for example, the insulating cover is divided into two in the width direction of the first part, and the divided insulating covers are assembled to the unit member from both sides in the stacking direction to insulate the negative electrode tab group from the case. It is conceivable. In this case, the insulating cover is a mechanism in which the first insulating cover attached from one end side in the stacking direction and the second insulating cover attached from the other end side in the stacking direction are fitted or locked between the lid and the conductive member Have. The first insulating cover has a portion disposed between the lid and the conductive member of the negative electrode, and a portion that covers the negative electrode tab group from one end side in the stacking direction. The second insulating cover has a portion disposed between the lid and the conductive member of the negative electrode, and a portion covering the negative electrode tab group from the other end side in the stacking direction. However, since the gap between the lid and the conductive member of the negative electrode in the unit member is small, the work of fitting or locking the first insulating cover and the second insulating cover between the lid and the conductive member of the negative electrode is complicated. It takes time.

  Moreover, the foil collection part of a negative electrode tab group may deform | transform so that it may swell toward the one end side of the lamination direction by the negative electrode tab group being curved. Then, the first insulating cover on one end side in the stacking direction is displaced between the negative electrode tab group and the case main body on one end side in the stacking direction, and is fitted or locked between the lid and the conductive member As a result, there is a possibility that insulation between the negative electrode tab group and the case main body can not be secured.

  The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a power storage device and a method of manufacturing the power storage device capable of easily insulating the negative electrode tab group and the case.

  An electric storage device for solving the above problems comprises a negative electrode tab group in which a positive electrode and a negative electrode are stacked in a state of being insulated and a negative electrode tab made of copper or copper alloy protruding from the negative electrode is stacked. A case having an electrode assembly, a case main body for housing the electrode assembly, and a plate-like lid for closing the opening of the case main body, fixed to the lid and exchanging electricity with the electrode assembly A negative electrode terminal, the negative electrode tab group and the negative electrode terminal are electrically connected, the lid, and a tab-side end surface of the electrode assembly facing the inner surface of the lid and having the negative electrode tab group And the electrode assembly, the lid, the negative electrode terminal, and the negative electrode conductive member are integrated, and the negative electrode tab group includes the negative electrode conductive member and the negative electrode conductive member. Before one side in the stacking direction An electricity storage device having a collection portion in which a negative electrode tab is gathered and curved from one end side to the other end side in the stacking direction, which is disposed between the lid and the negative electrode conductive member A first insulating portion for insulating the lid and the negative electrode conductive member, and the other end side of the stacking direction is disposed between the negative electrode tab group and the inner surface of the case main body, and the negative electrode tab group and the case The negative electrode tab group includes an insulating layer on an end face on one end side in the stacking direction of the foil collecting portion, and the insulating layer is formed of a ceramic. And a first layer facing the inner surface of the case main body, the second particle being present, and the first layer and the end face being mixed with one particle and flat second particles made of copper or a copper alloy. And a second layer located between The the gist.

  According to this, the first insulating portion of the insulating cover is supported by the negative electrode conductive member, whereby the second insulating portion of the insulating cover is located between the negative electrode tab group and the inner surface of the case main body at the other end side in the stacking direction. Located in For this reason, on the other end side in the stacking direction, the negative electrode tab group and the inner surface of the case main body are insulated by the second insulating portion of the insulating cover. In addition, the negative electrode tab group includes an insulating layer on an end face on one end side in the stacking direction of the foil collecting portion. The insulating layer is formed, for example, by low temperature thermal spraying of the first particles and the second particles on the end face of the foil collection portion. Therefore, at one end side in the stacking direction, the negative electrode tab group and the inner surface of the case main body are insulated by the insulating layer. Therefore, it is not necessary to fit or lock the insulating member between the negative electrode conductive member and the lid from one end side in the stacking direction for the insulation between the negative electrode tab group and the inner surface of the case body at the one end side in the stacking direction. . Therefore, the negative electrode tab group and the case main body can be easily insulated.

  In the first layer, the second particles connect the first particles to each other. Furthermore, since the second particles of the second layer are made of the same copper or copper alloy as the negative electrode tab, the second particles increase the adhesion of the second layer to the end face of the foil collection portion. For this reason, the first layer can be fixed to the foil collector by the second layer. Therefore, even if the foil tab portion is deformed so as to bulge toward one end side in the stacking direction because the negative electrode tab group is curved, it is possible to prevent the first layer from falling off the foil portion, and the case main body The first layer facing the inner surface can ensure insulation between the negative electrode tab group and the inner surface of the case body.

  In a method of manufacturing a power storage device for solving the above problems, a negative electrode is formed by laminating a positive electrode and a negative electrode in an insulated state and laminating a negative electrode tab made of copper or a copper alloy protruding from the negative electrode. An electrode assembly having a tab group, a case body accommodating the electrode assembly, and a case having a plate-like lid closing the opening of the case body, fixed to the lid, the electrode assembly and electricity And electrically connect the negative electrode tab group to the negative electrode terminal, and the lid, the tab of the electrode assembly facing the inner surface of the lid, the negative electrode tab group being present And a negative electrode conductive member disposed between the side end face, and the electrode assembly, the lid, the negative electrode terminal, and the negative electrode conductive member are integrated as a unit member, and the negative electrode tab group is the positive electrode. An electrode and the negative A manufacturing method of a power storage device having a foil collecting portion in which the negative electrode tab is gathered and collected at one end side in the stacking direction of the electrode, and curving from one end side to the other end side in the stacking direction, The first insulating portion of the insulating cover having the first insulating portion and the second insulating portion is disposed between the lid and the negative electrode conductive member in the unit member, and the second insulating portion is disposed in the other of the stacking direction. An insulating cover mounting step of arranging the negative electrode tab group from the end side to cover the negative electrode tab group, and an end surface on one end side of the laminating direction in the foil collecting portion of the negative electrode tab group from first particles and copper or copper alloy The second particles are low-temperature sprayed to form a first layer in which the first particles and the second particles are mixed, the second particles are present, and are positioned between the first layer and the end face Insulation forming an insulating layer having a second layer And forming step, the following insulating cover attaching step and the insulating layer forming step, and subject matter to include a housing step of housing the electrode assembly of the unit member in said case body.

  According to this, the first insulating portion of the insulating cover is supported by the negative electrode conductive member, and the second insulating portion of the insulating cover covers the negative electrode tab group from the other end side in the stacking direction. Therefore, when the electrode assembly is accommodated in the case body, the second insulating portion is located between the negative electrode tab group and the inner surface of the case body. At the other end side in the stacking direction, the negative electrode tab group and the inner surface of the case main body are insulated by the second insulating portion of the insulating cover. In addition, an insulating layer is formed on the end face on one end side in the stacking direction in the foil collection portion of the negative electrode tab group by low-temperature spraying the first particles and the second particles. Therefore, when the electrode assembly is accommodated in the case body, the insulating layer is positioned between the negative electrode tab group and the inner surface of the case body. At one end side in the stacking direction, the negative electrode tab group and the inner surface of the case main body are insulated by the insulating layer.

  Therefore, it is not necessary to fit or lock the insulating member between the negative electrode conductive member and the lid from one end side in the stacking direction for the insulation between the negative electrode tab group and the inner surface of the case body at the one end side in the stacking direction. . Therefore, the negative electrode tab group and the case main body can be easily insulated.

  The second particles connect the first particles to each other in the first layer. Furthermore, since the second particles are made of the same copper or copper alloy as the negative electrode tab, the second particles increase the adhesion of the second layer to the end face of the foil collection portion. For this reason, the first layer can be fixed to the foil collector by the second layer. Therefore, even if the foil tab portion is deformed so as to bulge toward one end side in the stacking direction because the negative electrode tab group is curved, it is possible to suppress the first layer from falling off from the foil portion, and the negative electrode tab group And insulation between the inner surface of the case and the case body.

In the method of manufacturing the power storage device, it is preferable that the mixed particles of the first particles and the second particles be low-temperature sprayed in the insulating layer forming step.
According to this, since the specific gravity of the second particles is larger than the specific gravity of the first particles, the second particles reach the end face of the foil collector and are deposited earlier than the first particles, and the second layer is formed. Be done. Thereafter, the first particles and the second particles are deposited on the second layer to form a first layer. Therefore, after the second particles are sprayed to form the second layer, the mixed particles of the first particles and the second particles are sprayed to form the first layer, which is required for the insulating layer forming step. Time can be reduced.

  Further, in the method of manufacturing the electric storage device, in the insulating layer forming step, the spraying direction of the first particles and the second particles is inclined 10 to 80 degrees toward the electrode assembly with respect to the direction orthogonal to the end face. Is preferred.

  When the inclination angle is less than 10 degrees, there are many particles that do not become an insulating layer by scattering when colliding with the foil collection portion. If the inclination angle is greater than 80 degrees, particles that do not form an insulating layer will increase as a result of not colliding with the foil collector. Therefore, the insulating layer can be efficiently formed by setting the inclination angle to 10 to 80 degrees.

  According to the present invention, the negative electrode tab group and the case can be easily insulated.

The disassembled perspective view of the secondary battery of embodiment. (A) is sectional drawing of a secondary battery, (b) is an enlarged view of (a). Sectional drawing of a secondary battery. Sectional drawing of a thermal spraying apparatus. (A), (b) is sectional drawing which shows an insulating layer formation process.

Hereinafter, one embodiment in which a storage device and a method of manufacturing the storage device are embodied in a secondary battery and a method of manufacturing a secondary battery will be described according to FIGS. 1 to 5.
As shown in FIG. 1, a secondary battery 10 as a power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 12 and an electrolyte contained in a case 11. The case 11 has a rectangular parallelepiped case body 13 and a rectangular flat lid 14 closing the opening 13 a of the case body 13. The case main body 13 and the lid 14 constituting the case 11 are both made of metal (for example, stainless steel or aluminum). The secondary battery 10 of the present embodiment is a square battery whose appearance is square. In addition, the secondary battery 10 of the present embodiment is a lithium ion battery.

  The case body 13 has a rectangular plate-like bottom wall 13b, long side walls 13c erected from a pair of long side edges of the bottom wall 13b, and short sides erected from a pair of short side edges of the bottom wall 13b. And a side wall 13d. In the lid 14, a surface facing the inside of the case 11 is a lower surface 14 a as an inner surface, and a surface facing the outside of the case 11 is an upper surface 14 b. The case 11 is formed by welding the long side wall 13 c and the short side wall 13 d of the case main body 13 accommodating the electrode assembly 12 and the lid 14 closing the opening 13 a of the case main body 13. Further, the electrolytic solution is injected into the case 11 from a liquid injection port (not shown) formed on the lid 14 after welding the case body 13 and the lid 14.

  As shown in FIG. 2, the electrode assembly 12 includes a positive electrode 21 as a plurality of sheet-like positive electrodes, a negative electrode 22 as a plurality of sheet-like negative electrodes, and a plurality of sheet-like separators 23. And The electrode assembly 12 has a layered structure in which a separator 23 is interposed between the positive electrode 21 and the negative electrode 22 and laminated in a state of being insulated from each other.

  The positive electrode 21 has a rectangular sheet-like positive electrode metal foil (for example, aluminum foil) 24 and a positive electrode active material layer 25 present on both sides of the positive electrode metal foil 24. The positive electrode 21 includes a tab side edge 21 a at one of the edges along the pair of long sides. The positive electrode 21 has a positive electrode tab 26 as a tab having a shape protruding from a part of the tab side edge 21 a. The positive electrode tab 26 does not have the positive electrode active material layer 25 and is made of the positive electrode metal foil 24 itself. In the present embodiment, the positive electrode tab 26 is rectangular, and the lateral direction of the positive electrode tab 26 coincides with the direction along the tab side edge 21 a.

  The negative electrode 22 has a rectangular sheet-like negative electrode metal foil (for example, copper foil) 27 and a negative electrode active material layer 28 present on both sides of the negative electrode metal foil 27. The negative electrode 22 includes a tab side edge 22 a at one of the edges along the pair of long sides. The negative electrode 22 has a negative electrode tab 29 as a tab having a shape protruding from a part of the tab side edge 22a (see FIG. 1). The negative electrode tab 29 does not have the negative electrode active material layer 28 and is made of the negative electrode metal foil 27 itself. In the present embodiment, the negative electrode tab 29 has a rectangular shape, and the short side direction of the negative electrode tab 29 coincides with the direction along the tab side edge 22 a. The negative electrode tab 29 is present at a position not overlapping the positive electrode tab 26 in a state where the positive electrode 21 and the negative electrode 22 are stacked. The separator 23 has an insulating property, and insulates the positive electrode 21 from the negative electrode 22. The direction in which the positive electrode 21, the negative electrode 22, and the separator 23 are stacked is referred to as a stacking direction.

  The secondary battery 10 includes a positive electrode tab group 15 in which the positive electrode tabs 26 of each positive electrode 21 are stacked, and a negative electrode tab group 16 in which the negative electrode tabs 29 of each negative electrode 22 are stacked. The positive electrode tab group 15 and the negative electrode tab group 16 each have a foil collecting portion 17a in which a plurality of positive electrode tabs 26 and negative electrode tabs 29 are gathered to one end in the stacking direction, and from one end to the other end in the stacking direction. It is curved towards. In the positive electrode tab group 15 and the negative electrode tab group 16, a portion extending from one end side to the other end side in the stacking direction is taken as a first extending portion 17b. The end on the opposite side to the tab side edges 21a and 22a in the foil collector 17a and one end of the first extension 17b are continuous on one end side in the stacking direction. Further, in the positive electrode tab group 15 and the negative electrode tab group 16, the other end of the first extending portion 17b is curved from the other end side to the one end side in the stacking direction. A portion extending from the other end side to the one end side in the stacking direction is referred to as a second extending portion 17 c.

  The foil collector 17a of the negative electrode tab group 16 has a first end face A1 as an end face at one end face in the stacking direction and a second end face A2 at the other end face in the stacking direction. The first end face A1 is formed by the negative electrode tab 29 positioned at one end in the stacking direction, and the second end face A2 is formed by the negative electrode tab 29 positioned at the other end in the stacking direction.

  The electrode assembly 12 includes tab-side end surfaces 12 a on the end surfaces where the positive electrode tab group 15 and the negative electrode tab group 16 exist. The tab side end face 12 a is formed by gathering together the tab side edge 21 a of the positive electrode 21, the tab side edge 22 a of the negative electrode 22, and the edge of the separator 23. The electrode assembly 12 further includes a bottom end surface 12b at an end surface opposite to the tab end surface 12a, and a side end surface 12c at an end surface orthogonal to the tab end surface 12a and the bottom end surface 12b.

  As shown in FIG. 1, FIG. 2 (a), and FIG. 3, the secondary battery 10 is provided with the positive electrode terminal 18a and the negative electrode terminal 18b as an electrode terminal which exchanges electricity with the electrode assembly 12. The positive electrode terminal 18 a and the negative electrode terminal 18 b are each fixed to the lid 14. The positive electrode terminal 18a includes the positive electrode lead terminal 19a, and the negative electrode terminal 18b includes the negative electrode lead terminal 19a. Each lead terminal 19 a protrudes outward beyond the upper surface 14 b of the lid 14. The positive electrode lead terminal 19 a is bonded to the positive electrode conductive member 20 a, and the lower surface of the positive electrode conductive member 20 a is bonded to the positive electrode tab group 15. Thus, the positive electrode terminal 18 a is electrically connected to the electrode assembly 12 through the positive electrode conductive member 20 a and the positive electrode tab group 15. Similarly, the negative electrode lead-out terminal 19 a is joined to the negative electrode conductive member 20 b, and the lower surface of the negative electrode conductive member 20 b is joined to the negative electrode tab group 16. Thus, the negative electrode terminal 18 b is electrically connected to the electrode assembly 12 through the negative electrode conductive member 20 b and the negative electrode tab group 16. The positive electrode conductive member 20 a and the negative electrode conductive member 20 b are disposed between the lower surface 14 a of the lid 14 and the tab-side end surface 12 a of the electrode assembly 12.

  The positive electrode terminal 18a and the negative electrode terminal 18b respectively have a terminal connection member 19b electrically connected to the lead terminal 19a on the upper surface 14b of the lid 14 and an external connection electrically connected to the terminal connection member 19b outside the lid 14 A terminal 19c is provided. The positive electrode terminal 18 a and the negative electrode terminal 18 b have an outer insulating member 19 d on the top surface 14 b of the lid 14 so as to insulate the terminal connection member 19 b and the external connection terminal 19 c from the lid 14. The electrode assembly 12, the lid 14, the positive electrode terminal 18a, the negative electrode terminal 18b, the positive electrode conductive member 20a, and the negative electrode conductive member 20b are integrated as a unit member W. In the unit member W, the positive electrode tab group 15 and the negative electrode tab group 16 are in a state in which the foil collector 17a, the first extending portion 17b, and the second extending portion 17c are formed.

  The secondary battery 10 includes an insulating sheet 41 covering the electrode assembly 12. The insulating sheet 41 covers five surfaces of the electrode assembly 12 excluding the tab-side end surface 12 a, that is, the bottom-side end surface 12 b and the side end surface 12 c. The insulating sheet 41 insulates the bottom end face 12 b of the electrode assembly 12 from the bottom wall 13 b of the case body 13, and the side end face 12 c of the electrode assembly 12 and the long side wall 13 c or the short side wall 13 d of the case body 13. Insulate.

  The secondary battery 10 includes an insulating cover 50 made of resin. The insulating cover 50 extends in the longitudinal direction of the first portion 51 as a rectangular plate-like first insulating portion, a rectangular plate-like second portion 52 partially facing the first portion 51, and the first portion 51. A third portion 53 is provided as a second insulating portion that connects one side and one side along the longitudinal direction of the second portion 52. The insulating cover 50 is disposed such that the largest area of the first portion 51 and the second portion 52 is along the lower surface 14 a of the lid 14.

  As shown in FIG. 2A and FIG. 3, the first portion 51 is disposed between the lower surface 14a of the lid 14 and the upper surfaces of the positive electrode conductive member 20a and the negative electrode conductive member 20b. It is supported by the member 20b. The second portion 52 is located between the tab-side end surface 12 a of the electrode assembly 12 and the second extension 17 c of the positive electrode tab group 15 and the negative electrode tab group 16. The second portion 52 covers the second extending portion 17 c from the electrode assembly 12 side. The second extending portion 17 c is in a state of being inserted into a gap defined by the lower surfaces of the positive electrode conductive member 20 a and the negative electrode conductive member 20 b, the second portion 52, and the third portion 53.

  As shown in FIGS. 1 and 3, the longitudinal dimension of the second portion 52 is longer than the longitudinal dimension of the first portion 51. The second portion 52 includes the negative electrode insulating portion 52a on one end side in the longitudinal direction and the positive electrode insulating portion 52b on the other end side in the longitudinal direction. The negative electrode insulating portion 52 a is located between the lead terminal 19 a and the tab end surface 12 a of the negative electrode terminal 18 b and insulates the negative electrode terminal 18 b from the electrode assembly 12. The positive electrode insulating portion 52 b is located between the lead terminal 19 a and the tab-side end surface 12 a of the positive electrode terminal 18 a and insulates the positive electrode terminal 18 a from the electrode assembly 12.

  The third portion 53 covers the positive electrode tab group 15 and the negative electrode tab group 16 from the other end side in the stacking direction. The third portion 53 is located between the positive electrode tab group 15 and the negative electrode tab group 16 and the inner surface of the long side wall 13 c of the case main body 13 at the other end side in the stacking direction. The main body 13 is isolated.

  As shown in FIG. 3, the secondary battery 10 includes an insulating seal 42 that covers the positive electrode tab group 15 from one end side in the stacking direction. The insulating seal 42 has adhesiveness on the side facing the positive electrode tab group 15. Thus, the insulating seal 42 is attached to the foil collector 17 a of the positive electrode tab group 15. The insulating seal 42 insulates the positive electrode tab group 15 from the inner surface of the long side wall 13 c of the case main body 13 at one end side in the stacking direction.

  As shown in FIG. 2A and FIG. 3, the negative electrode tab group 16 includes the insulating layer 60 on the first end face A1 of the foil collector 17a. The insulating layer 60 of the present embodiment exists in the range from the tab-side end surface 12 a of the electrode assembly 12 to the portion joined to the negative electrode conductive member 20 b in the longitudinal direction of the negative electrode tab 29. It exists throughout. Further, the thickness of the insulating layer 60 in the present embodiment is about 100 μm.

  As shown in FIG. 2 (b), the insulating layer 60 has a first layer 61 and a second layer 62. In the first layer 61, the first particles P1 made of ceramic (in this embodiment, alumina) and the flat second particles P2 made of copper are mixed. The first layer 61 faces the inner surface of the long side wall 13 c of the case body 13 and insulates the negative electrode tab group 16 from the inner surface of the case body 13. In the first layer 61, the voids S and the second particles P2 exist between the first particles P1. The second particles P2 present between the first particles P1 connect the first particles P1 to each other. In the second layer 62, flat second particles P2 made of copper are present. The second layer 62 is located between the first layer 61 and the first end face A1. Since the second particles P2 are made of the same copper as the negative electrode tab 29, the lattice spacing is also the same as the negative electrode tab 29. Thus, the adhesion of the second layer 62 to the first end face A1 of the foil collector 17a is high.

  Next, in the method of manufacturing the secondary battery 10, the insulating cover attaching step of attaching the insulating cover 50 to the unit member W, the insulating layer forming step of forming the insulating layer 60, and the electrode assembly 12 of the unit member W The accommodation process accommodated in the case main body 13 will be described. The housing process is performed after the insulating cover attaching process and the insulating layer forming process.

  In the insulating cover attaching step, the insulating cover 50 is attached to the unit member W from the other end side to the one end side in the stacking direction. The first portion 51 is fitted between the lower surface 14 a of the lid 14 and the upper surfaces of the positive electrode conductive member 20 a and the negative electrode conductive member 20 b, and the tab side end face 12 a of the electrode assembly 12 and the positive electrode tab group 15 and the negative electrode tab group 16 The third portion 53 is fitted between the second extending portion 17c. Then, the first portion 51 is supported by the positive electrode conductive member 20a and the negative electrode conductive member 20b. The third portion 53 is disposed in a state of covering the positive electrode tab group 15 and the negative electrode tab group 16 from the other end side in the stacking direction.

  In the insulating layer forming step, the insulating layer 60 is formed by low-temperature spraying the mixed particles M of the first particles P1 and the second particles P2 on the first end face A1 of the foil collecting portion 17a. Here, the low temperature thermal spraying is to spray the thermal spray material at a temperature lower than the melting point of the thermal spray material. As a low temperature thermal spraying method, for example, powder jet deposition (PJD), cold spray (CS), aerosol deposition (AD) and the like are known. In the present embodiment, the mixed particles M are sprayed at normal temperature. The thermal spraying device 80 is used to form the insulating layer 60.

  As shown in FIG. 4, the thermal spraying device 80 includes a cylindrical casing 81. The housing 81 comprises an axially extending passage 82. The passage 82 opens at both ends of the housing 81. The cross-sectional area of the passage 82 in the direction orthogonal to the axial direction is taken as the passage area. The passage 82 is a first passage 82a near one axial end of the housing 81, a second passage 82b having a smaller passage area than the first passage 82a, and the other axial end of the housing 81, the second passage And a third passage 82c having a smaller passage area than 82b. The first passage 82 a includes a first opening 82 d opened at one end of the housing 81, and the third passage 82 c includes a second opening 82 e opened at the other end of the housing 81.

  The housing 81 includes a gas supply passage 83 extending from the outer peripheral surface of the housing 81 to the first passage 82 a. The gas supply passage 83 communicates the outside of the housing 81 with the first passage 82a. The gas supply passage 83 is located closer to the second passage 82 b in the axial direction of the housing 81.

  The housing 81 surrounds a part of the second passage 82b and includes a groove 84 in communication with the second passage 82b. The groove 84 can be said to be a portion that partially widens the passage area of the second passage 82b. The housing 81 includes a supply passage 85 extending from the outer peripheral surface of the housing 81 to the groove 84. The supply passage 85 communicates the outside of the housing 81 with the groove 84.

  The thermal spray apparatus 80 includes a cylindrical acceleration nozzle 86 inserted into the first passage 82a. The diameter of the acceleration nozzle 86 of the present embodiment is about 1 mm. The acceleration nozzle 86 is located closer to the first opening 82 d than the gas supply passage 83 in the axial direction. The gas supply passage 83 and the acceleration nozzle 86 communicate with each other. For example, an acceleration gas of about 0.2 to 0.5 [MPa] is supplied from the gas supply passage 83 to the acceleration nozzle 86. The acceleration gas of the present embodiment is nitrogen. A part of the acceleration nozzle 86 protrudes from the first opening 82 d to the outside of the housing 81 (outside the passage 82). The acceleration nozzle 86 is movable relative to the housing 81.

  The thermal spraying device 80 includes a cylindrical supply nozzle 87 inserted in the second passage 82b. The supply nozzle 87 is provided with a hole 87a which penetrates the supply nozzle 87 in the radial direction in the middle of the axial direction. The hole 87 a is connected to the groove 84. A portion of the feed nozzle 87 is within the acceleration nozzle 86.

  The thermal spraying device 80 includes a cylindrical gas supply pipe 88 inserted in the third passage 82c. A part of the gas supply pipe 88 is in the supply nozzle 87. The thermal spray apparatus 80 includes a gas supplier 89 that supplies a gas to the gas supply pipe 88. In the present embodiment, the gas supplied from the gas supplier 89 is nitrogen. The gas supply device 89 is attached to the gas supply pipe 88, and controls the timing, speed, and the like of supply of gas to the gas supply pipe 88.

  The thermal spraying device 80 includes a hopper 90 for containing mixed particles M in which the first particles P1 and the second particles P2 are mixed. The first particles P1 and the second particles P2 contained in the hopper 90 have substantially the same particle size. The hopper 90 is disposed on the outer peripheral surface of the housing 81 so as to communicate with the supply passage 85. The hopper 90 is connected to the supply nozzle 87 via the supply passage 85, the groove 84, and the hole 87a. Therefore, the mixed particles M are supplied to the supply nozzle 87 through the hopper 90, the supply passage 85, the groove 84, and the hole 87a.

  As shown to Fig.5 (a), the thermal spraying apparatus 80 is parallelly arranged with respect to the unit member W so that the front-end | tip part of the acceleration nozzle 86 may oppose 1st end surface A1 of the foil collector 17a of the negative electrode tab group 16. Ru. In the present embodiment, the acceleration nozzle 86 is disposed at an angle of about 45 degrees toward the electrode assembly 12 with respect to the direction X orthogonal to the first end face A1 of the foil collector 17a. That is, the thermal spraying direction Y of the mixed particles M is inclined at about 45 degrees with respect to the direction X orthogonal to the first end face A1 of the foil collector 17a. Further, the acceleration nozzle 86 is disposed such that the tip end thereof is separated from the first end face A1 of the foil collector 17a by approximately 0.5 to 1.8 mm. The acceleration nozzle 86 of the present embodiment moves in a circle on the first end face A1 of the foil collecting portion 17a while maintaining the distance between the tip end portion and the first end face A1 of the foil collecting portion 17a. The tab 29 moves from one end side to the other end side in the short direction. Therefore, the locus of the tip of the acceleration nozzle 86 with respect to the first end face A1 of the foil collector 17a is a locus such that circles continue in the lateral direction of the negative electrode tab 29 as shown by the two-dot chain line in FIG. It becomes. In the present embodiment, the moving speed of the acceleration nozzle 86 is set to, for example, 1 to 7 [m / s]. The moving range of the acceleration nozzle 86 in the longitudinal direction of the negative electrode tab 29 is slightly smaller than the range from the tab-side end surface 12 a of the electrode assembly 12 to the portion joined to the negative electrode conductive member 20 b.

  When the mixed particles M are low-temperature sprayed from the acceleration nozzle 86, the supply gas is supplied from the gas supply device 89 to the gas supply pipe 88, and the acceleration gas is supplied from the gas supply passage 83 to the acceleration nozzle 86. The mixed particles M are supplied from the hopper 90 to the supply nozzle 87 through the supply passage 85, the groove 84, and the hole 87a. Then, a negative pressure is generated inside the supply nozzle 87 by the flow of the accelerating gas, and the supply gas and the mixed particles M inside the supply nozzle 87 are accelerated to a predetermined velocity (for example, 200 to 500 [m / s]). The acceleration nozzle 86 sprays at high speed toward the first end face A1 of the foil collector 17a.

  In the jetted mixed particle M, since the specific gravity of copper is larger than that of alumina, the second particle P2 collides with the first end face A1 of the foil collector 17a earlier than the first particle P1. A portion of the first end face A1 of the foil collector 17a is scraped by the collision of the second particles P2. The second particles P2 become flat due to the application of a compressive force when reaching the first end face A1 of the foil collector 17a. As a result, flat second particles P2 are deposited on the first end face A1 of the foil collector 17a, and the second layer 62 is formed. In addition, a part of 2nd particle | grains P2 injected from the acceleration nozzle 86 is oxidized until it reaches 1st end surface A1.

  On the other hand, the first particles P1 are deposited on the second layer 62 in order to reach the foil collector 17a after the second particles P2 have been deposited. Also, the second particles P2 are deposited on the second layer 62 together with the first particles P1. The first particles P1 and the second particles P2 are deposited in a state in which the second particles P2 and the voids S exist between the first particles P1. The second particles P2 connect the first particles P1 to each other. On the second layer 62, a first layer 61 in which the first particles P1 and the flat second particles P2 are mixed is formed. The second layer 62 is located between the first end face A1 of the foil collector 17a and the first layer 61. Thereby, the insulating layer 60 is completed.

  The acceleration nozzle 86 moves in the lateral direction of the negative electrode tab 29 while moving in a circle on the first end face A1 of the foil collector 17a as described above. Therefore, a range from the tab-side end face 12a of the electrode assembly 12 in the longitudinal direction of the negative electrode tab 29 to the portion joined to the negative electrode conductive member 20b on the first end face A1 of the foil collector 17a of the negative electrode tab group 16; The insulating layer 60 is formed in the entire short direction of the negative electrode tab 29.

  In the storing step, the electrode assembly 12 of the unit member W is inserted into the case main body 13 from the bottom end surface 12 b side. In the unit member W, the insulating cover 50 is attached, the insulating seal 42 is attached to the positive electrode tab group 15, and the insulating layer 60 is formed on the negative electrode tab group 16. Therefore, in the state where the electrode assembly 12 is accommodated in the case main body 13, the third portion 53 of the insulating cover 50 is a length of the positive electrode tab group 15, the negative electrode tab group 16 and the case main body 13 at the other end side in the stacking direction. It is located between the inner surface of the side wall 13c. The insulating seal 42 is positioned between the positive electrode tab group 15 and the inner surface of the long side wall 13 c of the case main body 13 at one end side in the stacking direction. Furthermore, the insulating layer 60 is located between the negative electrode tab group 16 and the inner surface of the long side wall 13 c of the case main body 13 at one end side in the stacking direction.

Next, the effects of the present embodiment will be described along with the actions.
(1) By supporting the first portion 51 of the insulating cover 50 by the negative electrode conductive member 20b, the third portion 53 of the insulating cover 50 is the inner surface of the negative electrode tab group 16 and the case main body 13 at the other end side in the stacking direction. Located between Therefore, on the other end side in the stacking direction, the negative electrode tab group 16 and the inner surface of the case main body 13 are insulated by the third portion 53 of the insulating cover 50. In addition, the negative electrode tab group 16 includes the insulating layer 60 on the first end face A1 of the foil collector 17a. The insulating layer 60 is formed, for example, by low temperature thermal spraying the first particles P1 and the second particles P2 on the first end face A1 of the foil collector 17a. Therefore, at the one end side in the stacking direction, the negative electrode tab group 16 and the inner surface of the case main body 13 are insulated by the insulating layer 60. Therefore, for insulation between the negative electrode tab group 16 and the inner surface of the case main body 13 at one end side in the stacking direction, the insulating member is between the upper surface of the negative electrode conductive member 20b and the lower surface 14a of the lid 14 from one end side in the stacking direction. There is no need to fit or lock. Therefore, the negative electrode tab group 16 and the case main body 13 can be easily insulated.

  In the first layer 61, the second particles P2 connect the first particles P1 to each other. Furthermore, since the second particles P2 of the second layer 62 are made of the same copper as the negative electrode tab 29, the adhesion of the second layer 62 to the first end face A1 of the foil collector 17a is enhanced by the second particles P2. Therefore, the first layer 61 can be fixed to the foil collector 17 a by the second layer 62. Therefore, even if the negative electrode tab group 16 is curved and the foil collector 17a is deformed to bulge toward one end in the stacking direction, the first layer 61 can be prevented from dropping off from the foil collector 17a. The insulation between the negative electrode tab group 16 and the inner surface of the case main body 13 can be secured by the first layer 61 facing the inner surface of the case main body 13.

  (2) The mixed particles M are sprayed at normal temperature, so that the separator 23 can be prevented from melting when the insulating layer 60 is formed, and the binders of the positive electrode active material layer 25 and the negative electrode active material layer 28 are oxidized. It is possible to suppress the performance deterioration of the secondary battery 10 due to the above.

  (3) The insulating layer 60 has heat resistance because it includes the second particles P2 made of alumina. Therefore, it can suppress that the heat | fever at the time of welding the case main body 13 and the lid | cover 14 is transmitted to the negative electrode tab 29, and it can suppress that the separator 23 melts.

  (4) When connecting the first end face A1 of the foil collector 17a and the first particles P1 with an organic material, the organic material may be melted or decomposed when the organic material and the electrolytic solution come in contact with each other. . In the present embodiment, since the first end face A1 of the foil collecting portion 17a and the first particle P1 are connected by the second particle P2 made of the same copper as the negative electrode tab 29, the problem of melting or decomposition due to contact with the electrolytic solution Does not occur.

  (5) A tensile stress is generated on the negative electrode tab 29 constituting the first end face A1 of the foil collection portion 17a due to the bending of the negative electrode tab group 16. However, a compressive stress is generated by low temperature spraying the mixed particles M. Also occur. Therefore, the stress generated in the negative electrode tab 29 is relaxed. Therefore, the crack and breakage of the negative electrode tab 29 due to vibration and the like can be suppressed.

  (6) When the mixed particles M of the first particles P1 and the second particles P2 are subjected to low temperature spraying, the specific gravity of the second particles P2 is larger than the specific gravity of the first particles P1. The first end face A1 of the foil collector 17a is deposited prior to P1 and deposited to form a second layer 62. Thereafter, the first particles P1 and the second particles P2 are deposited on the second layer 62, and the first layer 61 is formed. Therefore, after the second particles P2 are sprayed to form the second layer 62, the mixed particles M of the first particles P1 and the second particles P2 are sprayed to form the first layer 61, The time required for the insulating layer formation process can be shortened.

  (7) The thermal spray direction Y of the mixed particles M is inclined at 45 degrees toward the electrode assembly 12 with respect to the direction X orthogonal to the first end face A1 of the foil collector 17a. When the inclination angle is smaller than 10 degrees, the number of mixed particles M which do not become the insulating layer 60 by scattering when colliding with the foil collecting portion 17 a increases. In addition, when the inclination angle is larger than 80 degrees, the number of mixed particles M that do not collide with the foil collector 17 a and do not become the insulating layer 60 is increased. Therefore, the insulating layer 60 can be efficiently formed by setting the inclination angle to 10 to 80 degrees.

  (8) The heat when welding the case main body 13 and the lid 14 is thermally insulated by the air gap S existing between the first particles P1 in the first layer 61 of the insulating layer 60 and is transmitted to the negative electrode tab 29 Be suppressed. Therefore, melting of the separator 23 can be suppressed. In addition, when the electrolytic solution is injected into the case 11, the electrolytic solution contacts the insulating layer 60. A part of the electrolytic solution in contact with the insulating layer 60 is stored inside the air gap S. The electrolytic solution stored in the space S flows down through the insulating layer 60, for example, when the secondary battery 10 is used for a long time. Thereby, the liquid quantity of the electrolyte solution accumulated on the bottom side of case 11 can be increased.

  (9) The second particles P2 thermally sprayed from the acceleration nozzle 86 are oxidized until reaching the first end face A1 of the foil collector 17a. The heat resistance of the insulating layer 60 is improved by the oxidized second particles P2. Therefore, it can suppress that the heat | fever at the time of welding the case main body 13 and the lid | cover 14 is transmitted to the negative electrode tab 29, and it can suppress that the separator 23 melts.

  (10) When the thermal spraying device 80 has a plurality of acceleration nozzles 86, the mixed particles M can be sprayed over a wide area, but the acceleration gases jetted from the acceleration nozzles 86 interfere with each other to form the insulating layer 60 well. May interfere. On the other hand, since the thermal spraying device 80 of the present embodiment has one movable acceleration nozzle 86, the mixed particles M can be sprayed over a wide area without causing a problem due to interference of the accelerating gas.

The above embodiment may be modified as follows.
In the positive electrode 21, the positive electrode active material layer 25 may be present on one side of the positive electrode metal foil 24. Similarly, in the negative electrode 22, the negative electrode active material layer 28 may be present on one side of the negative electrode metal foil 27.

  The positive electrode tab group 15 may not be curved from the other end side to the one end side in the stacking direction, and may not include the second extending portion 17c. Similarly, the negative electrode tab group 16 may not be curved from the other end side to the one end side in the stacking direction, and may not include the second extending portion 17c.

The insulating cover 50 may not have the second portion 52.
The insulating cover forming step may be performed after the insulating cover mounting step, or the insulating cover mounting step may be performed after the insulating layer forming step.

The insulating layer 60 may also be present on the second end face A2 of the foil collector 17a of the negative electrode tab group 16.
The insulating layer 60 may be present at least in a portion where the negative electrode tab group 16 can be in contact with the case body 13.

  The thickness of the insulating layer 60 may be changed, for example, in the range of 10 to 1000 μm. If the insulating layer 60 is thinner than 10 μm, the insulation between the negative electrode tab group 16 and the inner surface of the case main body 13 may be reduced. On the other hand, when the thickness of the insulating layer 60 is greater than 1000 μm, the insulating layer 60 may be peeled off from the foil collecting portion 17a.

The material of the negative electrode tab 29 (negative electrode metal foil 27) and the second particles P2 is not limited to copper, and may be a copper alloy.
In the above embodiment, the first particles P1 are particles of alumina, but may be particles of other ceramics such as aluminum nitride, silicon dioxide, silicon nitride, and the like.

  The particle sizes of the first particles P1 and the second particles P2 stored in the hopper 90 may be different. However, from the viewpoint of reducing the difference between the number of first particles P1 and the number of second particles P2 supplied from the hopper 90, the particle diameter of the first particles P1 and the second particles P2 is preferably the same.

The gas supplied from the gas supply device 89 is not limited to nitrogen, and may be, for example, an inert gas such as argon or helium, or air.
The accelerating gas supplied from the gas supply passage 83 is not limited to nitrogen, and may be, for example, an inert gas such as argon or helium, or air.

The setting of the thermal spraying device 80 (for example, the diameter of the acceleration nozzle 86, the pressure of the acceleration gas, etc.) may be appropriately changed according to the thickness and the formation range of the insulating layer 60.
○ In the insulating layer formation step, only the second particles P2 are subjected to low temperature spraying to form the second layer 62, and then the mixed particles M of the first particles P1 and the second particles P2 are subjected to low temperature spraying to form the first layer 61. You may form.

  ○ The temperature at which the mixed particles M are sprayed at a low temperature may be higher than normal temperature as long as the temperature is lower than the melting point of the second particles P2, but the separator 23 does not melt or the performance of the secondary battery 10 is not degraded It is preferable to thermally spray the mixed particles M at a low temperature (for example, 70 ° C. or less).

  ○ The thermal spray direction Y of the mixed particles M may coincide with the direction X orthogonal to the first end face A1 of the foil collector 17a, but with respect to the direction X orthogonal to the first end face A1 of the foil collector 17a Preferably, it is inclined at 10 to 80 degrees to the electrode assembly 12 side.

The distance between the first end face A1 of the foil collector 17a and the tip of the acceleration nozzle 86 is not limited to 0.5 to 1.8 mm, and may be changed as appropriate.
The moving speed of the acceleration nozzle 86 is not limited to 1 to 7 m / s, and may be changed as appropriate.

  In the above embodiment, when the mixed particles M are irradiated at low temperature, the acceleration nozzle 86 is moved with respect to the negative electrode tab group 16, but even if the negative electrode tab group 16 is moved with respect to the fixed acceleration nozzle 86 Alternatively, both the negative electrode tab group 16 and the acceleration nozzle 86 may be moved. For example, while moving the unit member W from one side to the other side of the negative electrode tab 29 in the lateral direction, the acceleration nozzle 86 may be reciprocated in the longitudinal direction of the negative electrode tab 29.

  The number of acceleration nozzles 86 is not limited to one, and may be two or more. Moreover, when using multiple acceleration nozzles 86, it is preferable to arrange in zigzag form. In this case, the interference between the acceleration gases jetted from the respective acceleration nozzles 86 can be suppressed as compared with the case where they are arranged in a lattice.

The power storage device is also applicable to power storage devices other than secondary batteries, such as capacitors.
The secondary battery 10 may be another secondary battery other than a lithium ion secondary battery. The point is that the ions move between the active material for the positive electrode and the active material for the negative electrode and the charge is taught.

DESCRIPTION OF SYMBOLS 10 Secondary battery as an electrical storage device 11 Case 12 electrode assembly 13 Case main body 13a Opening 14 Lid 16 Negative electrode tab group 17a Foil collector 18b Negative electrode terminal , 20b: negative electrode conductive member, 21: positive electrode, 22: negative electrode, 29: negative electrode tab, 50: insulating cover, 51: first portion as first insulating portion, 53: third portion as second insulating portion 60: insulating layer, 61: first layer, 62: second layer, P1: first particle, P2: second particle, M: mixed particle, A1: first end face as an end face, W: unit member

Claims (4)

An electrode assembly having a negative electrode tab group in which a positive electrode and a negative electrode are stacked in an insulated state, and a negative electrode tab made of copper or copper alloy protruding from the negative electrode is stacked;
A case main body for housing the electrode assembly, and a case having a plate-like lid closing an opening of the case main body;
A negative electrode terminal fixed to the lid for exchanging electricity with the electrode assembly;
The negative electrode tab group and the negative electrode terminal are electrically connected, and disposed between the lid and the tab-side end surface of the electrode assembly facing the inner surface of the lid and in which the negative electrode tab group is present A negative electrode conductive member,
Equipped with
The electrode assembly, the lid, the negative electrode terminal and the negative electrode conductive member are integrated;
The negative electrode tab group has a foil collection portion in which the negative electrode tab is gathered at one end side in the stacking direction of the positive electrode and the negative electrode, and is curved from one end side to the other end in the stacking direction Storage device, and
A first insulating portion disposed between the lid and the negative electrode conductive member and insulating the lid and the negative electrode conductive member, and the negative electrode tab group and the inner surface of the case main body at the other end side in the stacking direction An insulating cover having a second insulating portion disposed between the negative electrode tab group and the case main body.
The negative electrode tab group includes an insulating layer on an end face on one end side in the stacking direction in the foil collecting portion,
In the insulating layer, a first particle made of ceramic and a flat second particle made of copper or a copper alloy are mixed, and a first layer facing the inner surface of the case main body and the second particle are present. And a second layer positioned between the first layer and the end face. An electrode assembly having a negative electrode tab group in which a positive electrode and a negative electrode are stacked in an insulated state, and a negative electrode tab made of copper or copper alloy protruding from the negative electrode is stacked;
A case main body for housing the electrode assembly, and a case having a plate-like lid closing an opening of the case main body;
A negative electrode terminal fixed to the lid for exchanging electricity with the electrode assembly;
The negative electrode tab group and the negative electrode terminal are electrically connected, and disposed between the lid and the tab-side end surface of the electrode assembly facing the inner surface of the lid and in which the negative electrode tab group is present A negative electrode conductive member,
Equipped with
The electrode assembly, the lid, the negative electrode terminal, and the negative electrode conductive member are integrated as a unit member,
The negative electrode tab group has a foil collection portion in which the negative electrode tab is gathered at one end side in the stacking direction of the positive electrode and the negative electrode, and is curved from one end side to the other end in the stacking direction A method of manufacturing a storage battery,
The first insulating portion of the insulating cover having the first insulating portion and the second insulating portion is disposed between the lid and the negative electrode conductive member in the unit member, and the second insulating portion is in the stacking direction. An insulating cover attaching step of arranging so as to cover the negative electrode tab group from the other end side;
The first particles made of ceramic and the second particles made of copper or a copper alloy are low-temperature sprayed on the end face on one end side in the laminating direction in the foil collection portion of the negative electrode tab group to obtain the first particles and the second particles. Forming an insulating layer having a first layer in which the first and second particles are mixed, and a second layer located between the first layer and the end face in which the second particle is present, and
An accommodating step of accommodating the electrode assembly of the unit member in the case main body after the insulating cover attaching step and the insulating layer forming step;
A method of manufacturing a power storage device, comprising:   The method according to claim 2, wherein the mixed particles of the first particles and the second particles are low-temperature sprayed in the insulating layer forming step. 4. The insulating layer forming step according to claim 2, wherein the thermal spraying direction of the first particles and the second particles is inclined 10 to 80 degrees toward the electrode assembly with respect to the direction orthogonal to the end face. Method of manufacturing a power storage device.