JP2019029060A - Power storage device - Google Patents

Abstract

To provide a power storage device by which a foreign material from a safety valve can be suppressed from being scattered to outside in a nail pricking test.SOLUTION: A power storage device 1 comprises: an electrode assembly 10 arranged by laminating a plurality of positive electrodes 11 and a plurality of negative electrodes 12 to alternate with a corresponding separator 13 arranged therebetween; a case 20 which contains the electrode assembly 10; a positive electrode terminal structure M including a positive electrode terminal 23 connected to a positive electrode tab 14b; a negative electrode terminal structure N including a negative electrode terminal 24 connected to a negative electrode tab 16b; a safety valve 40 provided on the case 20; and a shield member 50 disposed between the case 20 and the electrode assembly 10 and covering the safety valve 40. The shield member 50 is positioned between the positive electrode terminal structure M and the negative electrode terminal structure N by the positive electrode terminal structure M and the negative electrode terminal structure N.SELECTED DRAWING: Figure 6

Description

  One aspect of the present invention relates to a power storage device.

  Patent Document 1 describes a secondary battery mounted on, for example, an electric vehicle. The secondary battery includes a battery casing, a cell attached to the battery casing, a battery upper lid, and a safety protection device. The battery top cover is provided with a pressure relief valve, a positive terminal and a negative terminal. Each of the positive electrode terminal and the negative electrode terminal is connected to each of the positive electrode and the negative electrode of the cell via the conductive connector. The safety protection device is located between the battery top cover and the cell, and is fixed in accordance with the pressure relief valve.

Japanese Patent Laid-Open No. 2006-96129

  By the way, in the secondary battery described in Patent Document 1, when a nail penetration test, which is one of the evaluation tests, is performed, the nail breaks the separator between the positive electrode and the negative electrode, and the positive electrode and the negative electrode Is short-circuited in the case. When a short circuit occurs, heat is generated around the short circuit part, the electrolyte component is decomposed by the heat generated around the short circuit part, and gas is generated in the case. Then, the pressure inside the case rises and the pressure relief valve opens, but when gas is released from the pressure relief valve to the outside of the case, a part of the electrode is scraped off by the high pressure gas and gets on the gas as it is. There is a risk of splashing outside the case. For this reason, in the secondary battery described in Patent Document 1, a shielding member that suppresses the scattering of foreign matters to the outside is provided. However, there are cases where the conductive connector or the like disposed in the vicinity of the shielding member is melted by the high-temperature gas generated from the cell and scattered as foreign matter. Here, since the shielding member is disposed only directly under the pressure relief valve, the distance between the pressure relief valve and a component (such as a conductive connector) that can be discharged to the outside as a foreign object during the nail penetration test is small. For this reason, the generated high-temperature foreign matter may pass through the gas flow path provided in the shielding member and scatter to the outside from the pressure relief valve.

  An object of one aspect of the present invention is to provide a power storage device that can suppress foreign matter from scattering from a safety valve to the outside during a nail penetration test.

  A power storage device according to one aspect of the present invention includes an electrode assembly in which a plurality of positive electrodes each having a positive electrode tab and a plurality of negative electrodes each having a negative electrode tab are alternately stacked via a separator, and the electrode assembly A positive terminal structure that includes a positive terminal connected to the positive electrode tab at one end of the case and one end protruding from the wall of the case and the other end extending along the protruding direction of the one end. A negative electrode terminal structure including a negative electrode terminal protruding outside from the wall and having the other end connected to the negative electrode tab at the internal position of the case along the protruding direction of one end, a safety valve provided on the wall of the case, and the case A shielding member that is disposed between the wall portion and the electrode assembly and covers the safety valve, and the shielding member is formed between the positive electrode terminal structure and the negative electrode terminal structure by the positive electrode terminal structure and the negative electrode terminal structure. Positioned between That.

  In this power storage device, the shielding member disposed between the wall portion of the case and the electrode assembly is positioned between the positive terminal structure and the negative terminal structure by the positive terminal structure and the negative terminal structure. ing. In this configuration, the space shielded by the shielding member can be increased in the direction from the positive terminal structure to the negative terminal structure. Therefore, the distance between the safety member (for example, the positive electrode terminal, the negative electrode terminal, the positive electrode tab, or the negative electrode tab) that can be a source of foreign matters during the nail penetration test of the power storage device and the safety valve can be increased. In this case, even if the foreign matter generated from the conductive member passes through the shielding member, it is difficult for the foreign matter to splash outside from the safety valve. Therefore, in the power storage device, it is possible to prevent foreign matter from scattering from the safety valve to the outside at the time of breakage.

  In the direction from the positive electrode tab to the negative electrode tab in a plane orthogonal to the stacking direction of the plurality of positive electrodes and the plurality of negative electrodes, the positive electrode tab is positioned between an intermediate point between one end of the case and the center of the safety valve and one end of the case. However, in the direction from the positive electrode tab to the negative electrode tab, the negative electrode tab may be located between an intermediate point between the other end of the case and the center of the safety valve and the other end of the case. In this case, the distance between the positive electrode tab and the safety valve and the distance between the negative electrode tab and the safety valve can be increased. Therefore, even when a part of the positive electrode tab or the negative electrode tab is scraped and generated as a foreign material, the generated foreign material can be prevented from scattering from the safety valve to the outside.

  The shielding member may be provided with a plurality of slits extending along the stacking direction of the plurality of positive electrodes and the plurality of negative electrodes. In this case, since the slit is provided in the shielding member, the gas generated from the electrode assembly passes through the slit and is discharged from the safety valve. Thus, since the gas discharge path is shortened, the gas generated from the electrode assembly can be easily discharged from the safety valve. Moreover, it can suppress that a positive electrode or a negative electrode protrudes from a slit because the slit is extended along the lamination direction.

  According to one aspect of the present invention, there is provided a power storage device capable of suppressing foreign matter from scattering from a safety valve to the outside during a nail penetration test.

It is a perspective view which shows the electrical storage apparatus which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the electrical storage apparatus of FIG. It is a disassembled perspective view which shows an electrode assembly. It is a perspective view which shows the shielding member of FIG. It is a figure which shows the bottom face of the shielding member of FIG. It is sectional drawing along the VI-VI line of FIG. It is a figure for demonstrating the position where a positive electrode tab and a negative electrode tab are arrange | positioned.

  Hereinafter, various embodiments will be described in detail with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted. Each drawing may show an XYZ orthogonal coordinate system.

  FIG. 1 is a perspective view showing a power storage device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing the power storage device of FIG. The power storage device 1 shown in FIGS. 1 and 2 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, and can be used as a battery for various vehicles such as a hybrid vehicle or an electric vehicle. The power storage device 1 includes an electrode assembly 10 in which a plurality of positive electrodes 11 and a plurality of negative electrodes 12 are stacked, a case 20 that houses the electrode assembly 10, a positive terminal structure M including a positive terminal 23, and a negative terminal 24. , A safety valve 40 provided in the case 20, a shielding member 50 that covers the safety valve 40, and a sealing member 60 that closes the liquid injection hole provided in the case 20.

  As shown in FIG. 3, the electrode assembly 10 includes a plurality of sheet-like positive electrodes 11 each having a positive electrode tab 14b and a plurality of sheet-like negative electrodes (electrodes) 12 each having a negative electrode tab 16b. Have. The positive electrodes 11 and the negative electrodes 12 are alternately stacked via, for example, sheet-like separators 13. Each of the positive electrode 11, the negative electrode 12, and the separator 13 has a rectangular shape, for example. Note that the separator 13 may have a bag shape instead of a sheet shape. In this case, the positive electrode 11 is alternately laminated with the negative electrode 12 in a state of being surrounded by the separator 13. In the following description, the direction in which the plurality of positive electrodes 11 and the plurality of negative electrodes 12 are stacked will be described as the stacking direction (X-axis direction).

  The positive electrode 11 includes, for example, a metal foil 14 that is a positive electrode current collector made of a conductive material such as aluminum, and a positive electrode active material layer 15 formed on both surfaces of the metal foil 14. The metal foil 14 includes a positive electrode main body portion 14a that is rectangular when viewed from the stacking direction, and a positive electrode tab 14b that is provided integrally with the positive electrode main body portion 14a. The positive electrode tab 14b protrudes from the upper edge portion 14c of the positive electrode main body portion 14a. The positive electrode active material layer 15 is formed on both front and back surfaces of the positive electrode main body portion 14a. The positive electrode active material layer 15 is a porous layer formed including a positive electrode active material and a binder. Examples of the positive electrode active material include composite oxide, metallic lithium, and sulfur. The composite oxide includes, for example, at least one of manganese, nickel, cobalt, and aluminum and lithium.

  The negative electrode 12 includes a metal foil 16 that is a negative electrode current collector made of a conductive material such as copper, and a negative electrode active material layer 17 formed on both surfaces of the metal foil 16. The metal foil 16 includes a negative electrode main body 16a that is rectangular when viewed from the stacking direction, and a negative electrode tab 16b that is provided integrally with the negative electrode main body 16a. The negative electrode tab 16b protrudes from the upper edge portion 16c of the negative electrode main body portion 16a. The negative electrode active material layer 17 is formed on both the front and back surfaces of the negative electrode main body portion 16a. The negative electrode active material layer 17 is a porous layer formed including a negative electrode active material and a binder. Examples of the negative electrode active material include graphite, highly oriented fluffite, carbon such as mesocarbon microbeads, hard carbon and soft carbon, alkali metals such as lithium and sodium, metal compounds, and SiOx (0.5 ≦ x ≦ 1. 5) and the like, or boron-added carbon and the like.

  The separator 13 has a rectangular shape when viewed from the stacking direction. Examples of the material of the separator 13 include a porous film made of a polyolefin-based resin such as polyethylene (PE) and polypropylene (PP), or a woven or non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose, or the like.

  As shown in FIG. 2, the electrode assembly 10 includes an assembly main body 18 in which positive electrode main body portions 14 a of a plurality of positive electrodes 11 and negative electrode main body portions 16 a of a plurality of negative electrodes 12 are alternately stacked via separators 13. A positive electrode tab laminate 19a in which a plurality of positive electrode tabs 14b are laminated, and a negative electrode tab laminate 19b in which a plurality of negative electrode tabs 16b are laminated.

  The assembly body 18 includes an end surface 18a from which the positive electrode tab laminate 19a (positive electrode tab 14b) and the negative electrode tab laminate 19b (negative electrode tab 16b) protrude, a bottom surface 18b opposite to the end surface 18a, an end surface 18a, and a bottom surface 18b. And side surfaces 18c and 18d extending in the direction intersecting with. The pair of side surfaces 18c are disposed on opposite sides of the assembly body 18 in the X-axis direction. The pair of side surfaces 18d are disposed on opposite sides of the assembly body 18 in the Y-axis direction. The positive electrode tab laminate 19a (positive electrode tab 14b) and the negative electrode tab laminate 19b (negative electrode tab 16b) protrude from the end face 18a in the Z-axis direction. The positive electrode tab laminated body 19a and the negative electrode tab laminated body 19b are arranged to be separated from each other in the Y-axis direction.

  The case 20 includes a box-shaped main body portion 21 having an opening 21a and a lid portion 22 that closes the opening 21a. The main body 21 has a rectangular flat plate-shaped bottom portion 21b, a pair of first side walls 21c extending in the Z-axis direction from a pair of short side edges of the bottom portion 21b, a pair of first side walls 21c extending in the Z-axis direction from a long side edge of the bottom portion 21b, and And a pair of second side walls 21d intersecting the first side wall 21c. The case 20 is made of a metal material such as aluminum. For example, a non-aqueous (organic solvent-based) electrolytic solution is accommodated in the case 20. The lid portion 22 is provided with a liquid injection hole for injecting an electrolytic solution, and the liquid injection hole is sealed by a sealing member 60.

  The electrode assembly 10 is accommodated in the case 20 such that the pair of side surfaces 18c faces the pair of second side walls 21d of the case 20 and the pair of side surfaces 18d faces the pair of first side walls 21c of the case 20. ing. An insulating film 30 is disposed between the electrode assembly 10 and the case 20. The insulating film 30 has a box shape having an opening 31 and encloses the electrode assembly 10. The insulating film 30 is made of, for example, an insulating resin material.

  The positive terminal structure M includes a positive terminal 23 and a first insulating member 28 provided on the case 20. The negative terminal structure N includes a negative terminal 24 and a second insulating member 29 provided on the case 20. Each of the positive electrode terminal 23 and the negative electrode terminal 24 is provided on the lid portion 22 and can be electrically connected to the outside. The positive terminal 23 and the negative terminal 24 are spaced apart from each other. One end of the positive electrode terminal 23 protrudes from the lid portion 22 (wall portion) of the case 20 to the outside. The other end of the positive electrode terminal 23 is connected to the positive electrode tab laminate 19a at an internal position of the case 20 along the protruding direction of one end of the positive electrode terminal 23 (the Z-axis direction passing through one end of the positive electrode terminal 23). The positive electrode terminal 23 penetrates the lid portion 22 and protrudes from the case 20 in the Z-axis direction, and a plate-like portion 23b connected to the end portion of the shaft portion 23a in the case 20 and extending in the XY plane. And have. One end of the negative electrode terminal 24 protrudes from the lid portion 22 (wall portion) of the case 20 to the outside. The other end of the negative electrode terminal 24 is connected to the negative electrode tab laminate 19b at an internal position of the case 20 along the protruding direction of one end of the negative electrode terminal 24 (Z-axis direction passing through one end of the negative electrode terminal 24). The negative electrode terminal 24 penetrates the lid portion 22 and protrudes from the case 20 in the Z-axis direction, and a plate-like portion 24b connected to the end of the shaft portion 24a in the case 20 and extending in the XY plane. And have. Each of the positive electrode terminal 23 and the negative electrode terminal 24 is fixed to the lid portion 22 by a nut 27 via a seal member 25 and an insulating ring 26.

  The first insulating member 28 is attached to the positive electrode terminal 23 in the case 20. The first insulating member 28 covers the plate-like portion 23 b of the positive electrode terminal 23. The first insulating member 28 is connected to the first portion 28 a disposed between the plate-like portion 23 b and the lid portion 22 around the shaft portion 23 a of the positive electrode terminal 23, and is connected to the first portion 28 a. And a second portion 28b covering the side surface 23b1. The first portion 28 a covers the entire circumference of the side surface 23 b 1 of the plate-like portion 23 b of the positive electrode terminal 23. The first portion 28 a is provided with a through hole through which the shaft portion 23 a of the positive electrode terminal 23 passes. The second portion 28b extends from the edge of the first portion 28a along the Z-axis direction. The lower surface 23b2 of the plate-like portion 23b facing the end surface 18a of the electrode assembly 10 is exposed from the first insulating member 28, and is directly connected to the positive electrode tab laminate 19a. The positive electrode terminal 23 and the positive electrode tab laminate 19a are welded, for example, by laser welding.

  Similarly, the second insulating member 29 is attached to the negative electrode terminal 24 in the case 20. The second insulating member 29 covers the plate-like portion 24 b of the negative electrode terminal 24. The second insulating member 29 is connected to the first portion 29a and the first portion 29a disposed between the plate-like portion 24b and the lid portion 22 around the shaft portion 24a of the negative electrode terminal 24, and the plate-like portion 24b. And a second portion 29b covering the side surface 24b1. The first portion 29 a covers the entire circumference of the side surface 24 b 1 of the plate-like portion 24 b of the negative electrode terminal 24. The first portion 29a is provided with a through hole through which the shaft portion 24a of the negative electrode terminal 24 passes. The second portion 29b extends along the Z-axis direction from the edge of the first portion 29a. A lower surface 24b2 of the plate-like portion 24b facing the end surface 18a of the electrode assembly 10 is exposed from the second insulating member 29 and is directly connected to the negative electrode tab laminate 19b. The negative electrode terminal 24 and the negative electrode tab laminate 19b are welded, for example, by laser welding.

  The safety valve 40 is provided on the lid portion 22 of the case 20. The safety valve 40 can be disposed between the positive terminal 23 and the negative terminal 24 in the Y-axis direction. The safety valve 40 closes the through hole that penetrates the lid portion 22. The safety valve 40 is provided with a notch, and the notch is released when the pressure in the case 20 becomes greater than a predetermined value, and the gas in the case 20 is released to the outside.

  Next, the shielding member 50 will be described with reference to FIGS. FIG. 4 is a perspective view showing the shielding member of FIG. FIG. 5 is a diagram illustrating a bottom surface of the shielding member in FIG. 4. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

  In the power storage device 1, for example, at the time of a nail penetration test, a part of the electrode assembly 10 may be shaved and scattered as a foreign matter from the safety valve 40 to the outside. The shielding member 50 is a member that suppresses the scattering of foreign matter to the outside of the case 20 even when foreign matter is generated from the electrode assembly 10.

  As shown in FIGS. 4 to 6, the shielding member 50 has a rectangular parallelepiped shape as a whole, and includes an upper wall portion 51 that faces the lid portion 22, and a bottom wall portion 52 that faces the end surface 18 a of the electrode assembly 10. And a pair of side wall portions 53 that connect the upper wall portion 51 and the bottom wall portion 52. The upper wall portion 51 and the bottom wall portion 52 extend along the XY plane, and the pair of side wall portions 53 extend along the YZ plane. The shielding member 50 includes a first end 50a that is one end in the Y-axis direction and a second end 50b that is the other end in the Y-axis direction.

  In the Y-axis direction, the size of the upper wall portion 51 is smaller than the size of the bottom wall portion 52. Further, the upper wall portion 51 is unevenly distributed on the first end portion 50a side. The upper wall portion 51 is provided with a through hole 51a. When viewed from the Z-axis direction, the position of the through hole 51a corresponds to the position of the liquid injection hole, and the sealing member 60 is fitted in the through hole 51a. An opening 54 is formed in the first end portion 50 a by an upper wall portion 51, a bottom wall portion 52, and a pair of side wall portions 53. The bottom wall 52 is provided with a plurality of rectangular slits 56 extending along the stacking direction. Each slit 56 penetrates the bottom wall portion 52 in the Z-axis direction. The second end 50 b is provided with a side wall 55 that connects the bottom wall 52 and the pair of side walls 53. In the Z-axis direction, the dimension of the side wall part 55 is smaller than the dimension of the pair of side wall parts 53. Thereby, a gap is formed between the side wall portion 55 and the lid portion 22. When gas is generated during the nail penetration test, the gas is discharged from the safety valve 40 through the opening 54, the plurality of slits 56, and the gap between the side wall portion 55 and the lid portion 22.

  The shielding member 50 is disposed between the lid portion 22 and the end surface 18 a of the electrode assembly 10. The first end 50 a of the shielding member 50 is in contact with the second insulating member 29. Between the side surface 24 b 1 of the plate-like portion 24 b of the negative electrode terminal 24 and the first end portion 50 a of the shielding member 50, the second portion 29 b of the second insulating member 29 is disposed. The second end 50 b of the shielding member 50 is in contact with the first insulating member 28. A second portion 28 b of the first insulating member 28 is disposed between the side surface 34 b 1 of the plate-like portion 34 b of the positive electrode terminal 23 and the second end portion 50 b of the shielding member 50. As described above, the shielding member 50 includes the first insulating member 28 and the second insulating member 29 by the first insulating member 28 included in the positive terminal structure M and the second insulating member 29 included in the negative terminal structure N. Is positioned between and.

  In the nail penetration test of the electrode assembly 10, it is known that foreign matters are more likely to be generated near the positive electrode terminal 23 than near the negative electrode terminal 24. For this reason, it is preferable to make the 2nd end part 50b provided with the side wall part 55 contact | abut to the 1st insulating member 28. FIG. Thereby, since the foreign material generated in the vicinity of the positive electrode terminal 23 is shielded by the side wall portion 55, it is possible to suppress the foreign material from being scattered outside the case 20.

  Next, the positions of the positive electrode tab laminate 19a (positive electrode tab 14b) and the negative electrode tab laminate 19b (negative electrode tab 16b) will be described with reference to FIG. FIG. 7 is a view for explaining the positions where the positive electrode tab laminate 19a and the negative electrode tab laminate 19b are arranged. 7 shows a state in which the positive electrode tab laminate 19a and the negative electrode tab laminate 19b are not bent, and one surface of the lid portion 22 facing the end surface 18a of the electrode assembly 10 is orthogonal to the stacking direction. Yes.

  As shown in FIG. 7, in the Y-axis direction from the positive electrode tab laminate 19a (positive electrode tab 14b) to the negative electrode tab laminate 19b (negative electrode tab 16b) in the YZ plane intersecting the lamination direction, the positive electrode tab laminate 19a is The first intermediate point, which is an intermediate point between one end of the case 20 and the center of the safety valve 40, and one end of the case 20. Here, “one end of the case 20” is the outer surface of one first side wall 21c close to the positive electrode tab laminate 19a. The reference line A1 indicates the position of the center of the safety valve 40 in the Y-axis direction, the reference line A2 indicates the position of one end of the case 20 in the Y-axis direction, and the reference line C1 indicates the position of the first intermediate point in the Y-axis direction. ing.

  Similarly, in the Y-axis direction, the negative electrode tab laminate 19b is located between a second intermediate point that is an intermediate point between the other end of the case 20 and the center of the safety valve 40, and the other end of the case 20. . Here, “the other end of the case 20” is an outer surface of the other first side wall 21c close to the negative electrode tab laminate 19b. A reference line A3 indicates the position of the other end of the case 20 in the Y-axis direction, and a reference line C2 indicates the position of the second intermediate point in the Y-axis direction. The reference lines A1, A1, A3, and C2 extend in the Z-axis direction. The distance between the reference line A1 and the reference line A2 may be the same as the distance between the reference line A1 and the reference line A3. In the Y-axis direction, the distance between the reference line A1 and the reference line C1 and the distance between the reference line A1 and the reference line C2 are, for example, 30 to 45 mm.

  As described above, in the power storage device 1, the shielding member 50 disposed between the lid 22 and the electrode assembly 10 includes the first insulating member 28 and the negative terminal structure N included in the positive terminal structure M. Is positioned between the positive terminal structure M (first insulating member 28) and the negative terminal structure N (second insulating member 29). Thereby, the space shielded by the shielding member 50 can be increased in the Y-axis direction from the first insulating member 28 toward the second insulating member 29. Therefore, the distance between the safety valve 40 and the conductive member (for example, the positive electrode terminal 23, the negative electrode terminal 24, the positive electrode tab 14 b or the negative electrode tab 16 b) that can be a source of foreign matters during the nail penetration test of the power storage device 1 can be increased. In this case, even if the foreign matter generated from the conductive member passes through the shielding member 50, it is difficult for the foreign matter to scatter from the safety valve 40 to the outside. Therefore, in the power storage device 1, it is possible to prevent foreign matters from scattering from the safety valve 40 to the outside at the time of breakage.

  Also, by providing the shielding member 50 in this way, the area of the end surface 18a of the electrode assembly 10 shielded by the shielding member 50 can be increased, so that foreign matter generated in the electrode assembly 10 can be more reliably shielded. Is done. Therefore, it is possible to more reliably suppress foreign matters from being scattered outside.

  Further, in the Y-axis direction from the positive electrode tab 14b to the negative electrode tab 16b in the YZ plane orthogonal to the stacking direction of the plurality of positive electrodes 11 and the plurality of negative electrodes 12, the positive electrode tab 14b is formed between one end of the case 20 and the center of the safety valve 40. The negative electrode tab 16b is located between the intermediate point and one end of the case 20, and in the Y-axis direction from the positive electrode tab 14b to the negative electrode tab 16b, the intermediate point between the other end of the case 20 and the center of the safety valve 40, It is located between the other end of the case 20. Thereby, the distance between the positive electrode tab 14b and the safety valve 40 and the distance between the negative electrode tab 16b and the safety valve 40 can be increased. Therefore, even when a part of the positive electrode tab 14b or the negative electrode tab 16b is scraped and generated as a foreign material, the generated foreign material can be prevented from scattering from the safety valve 40 to the outside.

  The shielding member 50 is provided with a plurality of slits 56 extending along the stacking direction of the plurality of positive electrodes 11 and the plurality of negative electrodes 12. In this case, since the slit 56 is provided in the shielding member 50, the gas generated from the electrode assembly 10 passes through the slit 56 and is discharged from the safety valve 40. Thus, since the gas discharge path is shortened, the gas generated from the electrode assembly 10 can be easily discharged from the safety valve 40. Further, since the slit 56 extends along the stacking direction, the positive electrode 11 or the negative electrode 12 can be prevented from protruding from the slit 56.

  As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment.

  For example, in the above embodiment, the example in which the positive terminal structure M includes the positive terminal 23 and the first insulating member 28 and the negative terminal structure N includes the negative terminal 24 and the second insulating member 29 has been described. However, the positive terminal structure M and the negative terminal structure N may further include other members. Further, the positive terminal structure M may include only the positive terminal 23, and the negative terminal structure N may include only the negative terminal 24.

  In the above embodiment, the first end 50 a of the shielding member 50 is in contact with the second insulating member 29, and the second end 50 b of the shielding member 50 is in contact with the first insulating member 28 and is positioned. An example was described. However, another member may be disposed between the shielding member 50 and the first insulating member 28 or the second insulating member 29. When the positive terminal structure M does not include the first insulating member 28 and the negative terminal structure N does not include the second insulating member 29, the first end 50a of the shielding member 50 contacts the negative terminal 24. The second end 50b of the shielding member 50 may be in contact with the positive terminal 23 and positioned.

  Moreover, although the rectangular slit 56 extended along the lamination direction was demonstrated in the example provided in the shielding member 50, the shape and number of the slits 56 are not specifically limited, It can change suitably. In addition, the slit 56 may not be provided in the shielding member 50.

  DESCRIPTION OF SYMBOLS 1 ... Power storage device, 10 ... Electrode assembly, 11 ... Positive electrode, 12 ... Negative electrode, 13 ... Separator, 14b ... Positive electrode tab, 16b ... Negative electrode tab, 20 ... Case, 21 ... Body part, 21a ... Opening, 22 ... Lid part (Wall part), 23 ... positive electrode terminal, 24 ... negative electrode terminal, 28 ... first insulating member, 29 ... second insulating member, 40 ... safety valve, 50 ... shielding member, 56 ... slit, M ... positive electrode terminal structure, N ... negative electrode terminal structure.

Claims (3)

An electrode assembly in which a plurality of positive electrodes each having a positive electrode tab and a plurality of negative electrodes each having a negative electrode tab are alternately stacked via separators;
A case for housing the electrode assembly;
A positive electrode terminal structure including a positive electrode terminal, one end of which protrudes from the wall of the case to the outside and the other end of which is connected to the positive electrode tab at an internal position of the case along the protruding direction of the one end;
A negative electrode terminal structure including a negative electrode terminal, one end of which protrudes from the wall of the case to the outside and the other end of which is connected to the negative electrode tab at an internal position of the case along the protruding direction of the one end;
A safety valve provided on the wall of the case;
A shielding member disposed between the wall of the case and the electrode assembly and covering the safety valve;
With
The power storage device, wherein the shielding member is positioned between the positive terminal structure and the negative terminal structure by the positive terminal structure and the negative terminal structure. In the direction from the positive electrode tab to the negative electrode tab in a plane orthogonal to the stacking direction of the plurality of positive electrodes and the plurality of negative electrodes, the positive electrode tab is an intermediate point between one end of the case and the center of the safety valve, Located between the one end of the case,
The negative electrode tab is located between an intermediate point between the other end of the case and the center of the safety valve and the other end of the case in the direction from the positive electrode tab to the negative electrode tab. The power storage device according to 1.   The power storage device according to claim 1 or 2, wherein the shielding member is provided with a plurality of slits extending along a stacking direction of the plurality of positive electrodes and the plurality of negative electrodes.

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