Secondary battery

Abstract

The present invention provides a secondary battery which suppresses deterioration of battery characteristics. A laminated electrode body (20) and an electrolyte solution (15) are housed in a case main body (12). The positive electrode plate (22) and the negative electrode plate (24) are laminated, and the separator (26) is sandwiched between the positive electrode plate (22) and the negative electrode plate (24) and folded back. The positive electrode plates (22) and the negative electrode plates (24) face the opposing side surfaces (12b) inside the cylindrical case main body (12), and the positive electrode plates (22) and the negative electrode plates (24) are alternately arranged. A first end portion (26e1) and a second end portion (26e2) are formed on the lower portion of the laminated electrode body (20). The position of the upper edge (26eU) of the second end portion (26e2) is disposed below the liquid surface (15a) of the electrolyte (15).

Description

Technical Field

[0001] This invention relates to secondary batteries. Background Technology

[0002] International Publication No. 2019 / 064740 discloses a secondary battery for a stacked type that suppresses negative effects such as electrode deformation caused by creases in the separator. In this secondary battery, the separator is folded back at the electrode ends. In the secondary battery disclosed in this publication, the creases in the separator are separated from the end of the negative electrode by a predetermined length. Therefore, the negative effects caused by creases in the separator can be suppressed.

[0003] Patent Document 1: International Publication No. 2019 / 064740

[0004] However, the inventors of this application wish to suppress the degradation of battery characteristics. Summary of the Invention

[0005] The secondary battery disclosed herein comprises: an electrode body including a separator, a plurality of first electrode plates, and a plurality of second electrode plates with polarities different from the first electrode plates; an electrolyte; a casing body, which is cylindrical and houses the electrode body and the electrolyte; a first sealing plate installed at an opening on a first side of the casing body; and a second sealing plate installed at an opening on a second side of the casing body. The casing body has a pair of opposing side portions, and the plurality of first and second electrode plates are disposed inside the casing body opposite the pair of opposing side portions, with the first and second electrode plates alternately arranged. The separator is strip-shaped and passes through the upper... The diaphragm is disposed between the first electrode plate and the second electrode plate. The first end of the diaphragm is disposed on the outer periphery of the electrode body formed by the alternating opposition of the plurality of first electrode plates and the plurality of second electrode plates. The second end of the diaphragm is disposed on the outer periphery of the electrode body formed by the alternating opposition of the plurality of first electrode plates and the plurality of second electrode plates, and is fixed to the outer periphery of the electrode body by tape in a manner that overlaps with the outer side of the first end. When the pair of opposing side portions of the housing body are placed vertically, the upper edge of the second end of the diaphragm fixed by the tape is positioned below the electrolyte surface on the outer side of the electrode body inside the housing body.

[0006] Based on this secondary battery, the degradation of battery characteristics can be suppressed. Attached Figure Description

[0007] Figure 1This is a perspective view of the energy storage device 100 according to the first embodiment.

[0008] Figure 2 It is along Figure 1 A schematic longitudinal section view of line A-A.

[0009] Figure 3 This is a cross-sectional view of the stacked electrode body 20.

[0010] Figure 4 This is a schematic diagram showing the positive electrode plate 22 and the negative electrode plate 24.

[0011] Figure 5 This is a schematic diagram showing the interior of the main body 12 of the housing.

[0012] Figure 6 This is a rear view of the stacked electrode body 20.

[0013] Figure 7 This is a schematic diagram showing the interior of the housing body 12 when the energy storage device 100 is being charged.

[0014] Figure 8 This is a schematic diagram showing the interior of the housing body 12 when the energy storage device 100 is discharging.

[0015] Figure 9 This is a schematic diagram showing the interior of the energy storage device 100A according to the second embodiment.

[0016] Figure 10 This is a schematic diagram showing the interior of the energy storage device 100B according to the third embodiment.

[0017] Figure 11 This is a schematic diagram showing the interior of the energy storage device 100C according to the fourth embodiment.

[0018] Explanation of reference numerals in the attached figures:

[0019] 10…shell; 12…shell body; 12a…bottom part; 12b…side part; 12d…top part; 12e1, 12e2…ends; 12h1…opening on the first side; 12h2…opening on the second side; 15…electrolyte; 15a…liquid surface; 20…layered electrode body; 20F, 20Rr…side; 20B, 21B…layered electrode body; 20BF, 20Br…side; 21BF, 21Br…side; 20C, 21C…layered electrode body; 20CF, 20Cr…side; 21CF, 21Cr…side; 22…positive electrode plate; 22a …positive electrode current collector foil; 22b…positive electrode active material layer; 22c…uncoated part; 23…positive electrode tab; 24…negative electrode plate; 24a…negative electrode current collector foil; 24b…negative electrode active material layer; 24c…uncoated part; 25…negative electrode tab; 26…diaphragm; 26a…heat resistant layer; 26eU…upper edge; 28…adhesive layer; 29…tape; 29U…upper end; 30…positive electrode terminal; 32…positive electrode current collector; 40…negative electrode terminal; 42…negative electrode current collector; 100…energy storage device; 100A…energy storage device; 100B…energy storage device; 100C…energy storage device; GP…gap. Detailed Implementation

[0020] Hereinafter, preferred embodiments of the technology disclosed herein will be described with appropriate reference to the accompanying drawings. Matters requiring implementation of the technology disclosed herein, other than those specifically mentioned in this specification (e.g., the general structure and manufacturing process of energy storage devices that do not represent the technology disclosed herein), can be grasped by those skilled in the art based on prior art. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the field. Furthermore, in the following drawings, the same reference numerals are sometimes used to denote components or parts that perform the same function, and repeated descriptions are omitted or simplified.

[0021] <First Embodiment>

[0022] <Electric Storage Devices 100>

[0023] Figure 1 This is a perspective view of the energy storage device 100 according to the first embodiment. Figure 2 It is along Figure 1 A schematic longitudinal sectional view along line A-A shows the internal structure of the energy storage device 100. For example... Figure 1 As shown, the energy storage device 100 is square in shape (more specifically, cuboid in shape) composed of hexahedrons. In actual use, the energy storage device 100 is as follows... Figure 1That is how it is set up. In addition, in the following description, the reference numerals F, Rr, L, R, U, and D in the attached drawings represent front, back, left, right, top, and bottom, respectively, and the reference numerals X, Y, and Z in the attached drawings represent the width direction, the thickness direction orthogonal to the width direction, and the up and down direction orthogonal to both the width and thickness directions of the energy storage device 100, respectively.

[0024] like Figure 1 or Figure 2 As shown, the energy storage device 100 includes a housing 10, a stacked electrode body 20, a positive terminal 30, a negative terminal 40, and an electrolyte 15. The energy storage device 100 is a non-aqueous electrolyte secondary battery, such as a lithium-ion secondary battery. The energy storage device 100 is constructed by housing the stacked electrode body 20 and the electrolyte 15 within the housing 10, which houses the positive terminal 30 and the negative terminal 40. Furthermore, in this specification, the term "energy storage device" is a general term representing all devices capable of repeated charging and discharging, including secondary batteries such as lithium-ion batteries and nickel-metal hydride batteries, and capacitors such as lithium-ion capacitors and double-layer capacitors.

[0025] <Shell 10>

[0026] like Figure 2 As shown, the housing 10 is a frame that houses the stacked electrode body 20 and the electrolyte 15. Here, the housing 10 has a flat, bottomed cuboid shape (square). The material of the housing 10 is not particularly limited. The housing 10 can be made of metals such as aluminum or aluminum alloy. The housing 10 includes a housing body 12, a first sealing plate 14, and a second sealing plate 16.

[0027] <Shell Body 12>

[0028] The housing body 12 is a cylindrical component that houses the stacked electrode body 20 and the electrolyte 15. In this embodiment, the housing body 12 is a cylindrical component with openings at both ends. The housing body 12 can be formed, for example, by bending a single metal plate into a square tube shape and joining the seams (e.g., by welding). The housing body 12 can also be formed by joining multiple metal plates.

[0029] like Figure 2 As shown, the housing body 12 has a pair of narrow surfaces 12a and a pair of wide surfaces 12b. The narrow surfaces 12a are generally rectangular. The pair of narrow surfaces 12a are opposite each other in the Z direction, forming the upper and lower surfaces of the housing body 12. The narrow surfaces 12a extend in the X and Y directions. In this embodiment, the narrow surface 12a on one side in the Z direction (here, the lower side) is also referred to as the bottom surface 12aa. The narrow surface 12a on the other side in the Z direction (here, the upper side) is also referred to as the top surface 12ab. In the bottom surface 12aa and the top surface 12ab, the dimension along the width direction X is longer than the dimension along the thickness direction Y.

[0030] The pair of wide surfaces 12b is one example of a pair of opposing side surfaces in this invention. In the following description, "wide surface 12b" will also be referred to as "side surface 12b". The pair of wide surfaces 12b is generally rectangular. The pair of wide surfaces 12b is disposed between and continuous with the pair of narrow surfaces 12a. Here, the long sides of the pair of wide surfaces 12b are connected to the long sides of the pair of narrow surfaces 12a. The pair of wide surfaces 12b are opposed in the Y direction, forming the front and rear surfaces of the housing body 12. The wide surfaces 12b extend in the X and Z directions. The front side surface 12b of the side surfaces 12b is also referred to as side surface 12ba. Furthermore, the rear side surface 12b of the side surfaces 12b is also referred to as side surface 12bb.

[0031] like Figure 2 As shown, openings 12h1 and 12h2 are formed at both ends (ends 12e1 and 12e2) of the housing body 12 in the width direction X. Openings 12h1 and 12h2 are formed by the short sides of the bottom portion 12aa, the side portions 12ba and 12bb, and the top portion 12ab. Opening 12h1 is formed at the end 12e1 on the first side (right side) of the housing body 12. Opening 12h2 is formed at the end 12e2 on the second side (left side) of the housing body 12. Openings 12h1 and 12h2 are generally rectangular. A stacked electrode body 20 can be inserted through openings 12h1 and 12h2.

[0032] <Seal plate 14, seal plate 2>

[0033] The first sealing plate 14 is a component fitted to the opening 12h1 on the first side of the housing body 12. The second sealing plate 16 is a component fitted to the opening 12h2 on the second side of the housing body 12. The first sealing plate 14 and the second sealing plate 16 engage with the periphery of the openings 12h1 and 12h2 of the housing body 12. The first sealing plate 14 and the second sealing plate 16 are generally rectangular plate-shaped components. After the stacked electrode body 20 is housed in the housing body 12, the first sealing plate 14 and the second sealing plate 16 engage with the periphery of the openings 12h1 and 12h2. The first sealing plate 14 and the second sealing plate 16, which are engaged with the housing body 12, are opposite each other in the width direction X. A positive terminal 30 is provided on the first sealing plate 14. A negative terminal 40 is provided on the second sealing plate 16. The distance between the first sealing plate 14 and the second sealing plate 16 in the width direction X is longer than the length of the stacked electrode body 20 in the width direction X. Therefore, a gap GP is formed between the first sealing plate 14 and the stacked electrode body 20, and between the second sealing plate 16 and the stacked electrode body 20. Furthermore, an injection port (not shown) for injecting electrolyte 15 and a safety valve (not shown) that breaks when the internal pressure of the housing 10 exceeds a predetermined value may be provided on the first sealing plate 14 and the second sealing plate 16. This injection port and the safety valve may be provided, for example, on either the first sealing plate 14 or the second sealing plate 16.

[0034] The positive terminal 30 is disposed on the first sealing plate 14. The positive terminal 30 is an example of the first terminal in this invention. The positive terminal 30 is preferably made of metal, for example, more preferably aluminum or an aluminum alloy. The positive terminal 30 is connected inside the housing 10 to the positive electrode plate 22 (also see below) via the positive current collector 32. Figure 3 Electrical connection. Furthermore, the positive terminal 30 can also be installed, for example, via an insulator (not shown) or a washer (not shown).

[0035] The negative terminal 40 is disposed on the second sealing plate 16. The negative terminal 40 is an example of the second terminal in this invention. The negative terminal 40 is preferably made of metal, for example, more preferably of copper or a copper alloy. The negative terminal 40 is connected inside the housing 10 to the negative electrode plate 24 (also see below) via the negative current collector 42. Figure 3 Electrical connection. Additionally, the negative terminal 40 can also be installed via, for example, an insulator (not shown) or a washer (not shown).

[0036] The electrolyte 15 and the stacked electrode body 20 are housed together inside the housing 10. A portion of the electrolyte 15 permeates the stacked electrode body 20. The electrolyte 15 is, for example, a non-aqueous electrolyte containing a non-aqueous solvent (organic solvent) and a supporting salt (electrolyte salt, such as lithium salt, sodium salt). Examples of non-aqueous solvents include carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Examples of supporting salts include fluorinated lithium salts such as lithium hexafluoride phosphate (LiPF6). Typically, the electrolyte 15 is liquid, but it can also be gel-like. While not particularly limited, it is preferable that excess electrolyte 15 exists between the housing 10 and the stacked electrode body 20. In this embodiment, excess electrolyte 15 accumulates in the gap GP.

[0037] <Layered Electrode Body 20>

[0038] The stacked electrode body 20 is housed inside the housing body 12. In this embodiment, two stacked electrode bodies 20 are housed inside one housing body 12. The two stacked electrode bodies 20 are arranged in the thickness direction Y (see reference). Figure 5 Furthermore, the number of stacked electrode bodies 20 disposed inside a single housing body 12 can be one or more. Additionally, the stacked electrode bodies 20 can also be housed inside the housing 10 covered by a resin insulating sheet (electrode body holder).

[0039] Figure 3 This is a cross-sectional view of the stacked electrode body 20. (Example) Figure 3 As shown, the stacked electrode body 20 includes multiple positive electrode plates 22, multiple negative electrode plates 24 with different polarities from the positive electrode plates 22, a separator 26, and an adhesive layer 28 sandwiched between the positive electrode plates 22 and the separator 26 and between the negative electrode plates 24 and the separator 26 in the thickness direction Y. However, the adhesive layer 28 may also be provided between either the positive electrode plate 22 or the negative electrode plate 24 and the separator 26. The positive electrode plate 22 and the negative electrode plate 24 are located inside the cylindrical housing body 12 and on a pair of opposing side portions 12b (see reference). Figure 1 The positive electrode 22 and the negative electrode 24 are arranged alternately, facing each other. The separator 26 is formed in a strip shape. The separator 26 is disposed between the positive electrode 22 and the negative electrode 24 by being folded back in sequence. That is, the separator 26 is folded into a so-called tortuous shape. Here, the stacking direction of the multiple positive electrode 22 and the multiple negative electrode 24 is the thickness direction Y. In the following description, the thickness direction Y is also referred to as the stacking direction Y.

[0040] Figure 4 This is a schematic diagram showing the positive electrode plate 22 and the negative electrode plate 24. Furthermore, in Figure 4 In the text, the diaphragm 26 is omitted (see reference). Figure 3 The illustration is shown below. Figure 4 As shown, a positive electrode active material layer 22b is formed on the positive electrode plate 22, and a negative electrode active material layer 24b is formed on the negative electrode plate 24. Therefore, the positive electrode plate 22 and the negative electrode plate 24 of the stacked electrode body 20 overlap in an opposing manner while the positive electrode active material layer 22b and the negative electrode active material layer 24b are insulated from each other. The positive electrode active material layer 22b and the negative electrode active material layer 24b are separated by a separator 26 (see reference). Figure 3 Thus becoming an insulator. In this embodiment, such as Figure 3 As shown, the side of the laminated electrode body 20 on which the adhesive tape 29 (described later) is fixed is designated as side surface 20Rr. In this embodiment, the rear surface of the laminated electrode body 20 is side surface 20Rr. Furthermore, the front surface of the laminated electrode body 20 is designated as side surface 20F.

[0041] like Figure 4 As shown, typically, the positive electrode plate 22 includes a positive electrode current collector foil 22a and a positive electrode active material layer 22b fixed to at least one surface (here, both surfaces) of the positive electrode current collector foil 22a. The positive electrode current collector foil 22a is preferably a metal foil. In this embodiment, the positive electrode current collector foil 22a is made of, for example, aluminum or an aluminum alloy. The positive electrode active material layer 22b contains a positive electrode active material capable of reversibly absorbing and releasing charge carriers. The positive electrode active material can be the same as conventional materials and is not particularly limited. One example of a positive electrode active material is a lithium transition metal composite oxide containing nickel, cobalt, and manganese. The positive electrode active material layer 22b may also contain any component other than the positive electrode active material, such as a binder, conductive material, etc. Figure 3 As shown, the positive electrode plate 22 is bonded to the separator 26 on both sides in the stacking direction Y via an adhesive layer 28. Figure 4 As shown, an uncoated portion 22c without a positive electrode active material layer 22b is formed at one end of the positive electrode current collector foil 22a in the width direction X (here, the right side of the width direction X).

[0042] Typically, the negative electrode plate 24 includes a negative electrode current collector foil 24a and a negative electrode active material layer 24b fixed to at least one surface (here, both surfaces) of the negative electrode current collector foil 24a. The negative electrode current collector foil 24a is preferably a metal foil. In this embodiment, the negative electrode current collector foil 24a is, for example, made of copper, a copper alloy, etc. The negative electrode active material layer 24b contains a negative electrode active material capable of reversibly absorbing and releasing charge carriers. The negative electrode active material can be the same as conventional materials and is not particularly limited. Examples of negative electrode active materials include carbon materials such as graphite and silicon-based materials. The negative electrode active material layer 24b may also contain any components other than the negative electrode active material, such as binders, thickeners, dispersants, etc. Figure 3As shown, the negative electrode plate 24 is bonded to the separator 26 on both sides in the stacking direction Y via an adhesive layer 28. Figure 4 As shown, in this embodiment, an uncoated portion 24c without a negative electrode active material layer 24b is formed at one end of the negative electrode current collector foil 24a in the width direction X (here, the left side in the width direction X).

[0043] Figure 3 The separator 26 shown is an insulating sheet with multiple tiny through-holes that allow charge carriers to pass through. By sandwiching the separator 26 between the positive electrode plate 22 and the negative electrode plate 24, contact between the positive electrode plate 22 and the negative electrode plate 24 can be prevented, and charge carriers (e.g., lithium ions) can move between the positive electrode plate 22 and the negative electrode plate 24. The thickness of the separator 26 is not particularly limited, but in this embodiment it is about 20 μm.

[0044] like Figure 3 As shown, the diaphragm 26 has a first end 26e1 and a second end 26e2. The first end 26e1 is disposed on the outer periphery of a stacked electrode body 20 formed by alternating positive electrode plates 22 and negative electrode plates 24. The second end 26e2 is disposed on the outer periphery of the stacked electrode body 20 formed by alternating positive electrode plates 22 and negative electrode plates 24, and is fixed to the outer periphery of the stacked electrode body 20 by tape 29 in a manner overlapping the outer side of the first end 26e1. The first end 26e1 and the second end 26e2 are located rearward than the portion formed by the stacking of positive electrode plates 22 and negative electrode plates 24. The first end 26e1 and the second end 26e2 extend in the vertical direction Z from the portion formed by the stacking of positive electrode plates 22 and negative electrode plates 24 at approximately a right angle on the outer periphery. That is, the first end 26e1 and the second end 26e2 are approximately L-shaped when viewed from the side. Figure 3 In the laminated electrode body 20, a gap is formed between the first end 26e1 and the second end 26e2 in the thickness direction Y, but this gap is actually quite narrow. At the portion of the laminated electrode body 20 that is fixed by the tape 29 (described later) on the outer periphery, the second end 26e2 of the diaphragm 26 is longer than the first end 26e1. Therefore, the upper edge 26e1 of the second end 26e2 is located above the first end 26e1. The portion of the laminated electrode body 20 in which the first end 26e1 and the second end 26e2 are formed is such that, in the thickness direction Y, it is thicker than the other portions of the laminated electrode body 20 by the same amount as the thickness of the first end 26e1 and the second end 26e2. In this embodiment, the first end 26e1 and the second end 26e2 are formed at the lower part of the laminated electrode body 20. Although not particularly limited, in this embodiment, the vertical length Z of the first end 26e1 and the second end 26e2 is approximately 3 to 10 mm. Furthermore, for ease of illustration, the first end 26e1 and the second end 26e2 are shown in an exaggerated map.

[0045] The diaphragm 26 includes one or more heat-resistant layers (HRLs) 26a comprising a resin-based diaphragm substrate and a metal oxide such as alumina (Al2O3). In this embodiment, the heat-resistant layer 26a is formed on at least one side of the diaphragm 26. Here, the heat-resistant layer 26a is formed on the inner side of the second end 26e2 of the diaphragm 26 at the portion of the outer periphery of the laminated electrode body 20 that is fixed by the tape 29 described later.

[0046] Typically, the heat-resistant layer 26a contains inorganic fillers and a heat-resistant adhesive. By incorporating the heat-resistant layer 26a, thermal shrinkage of the diaphragm 26 can be suppressed, contributing to improvements in the energy storage device 100 (see reference). Figure 1 Safety of the membrane 26 is ensured. As inorganic fillers, ceramic particles such as alumina, zirconium oxide, boehmite, aluminum hydroxide, silica, and titanium dioxide are preferred. From the viewpoint of suppressing thermal shrinkage of the membrane 26, aluminum-containing compounds are particularly preferred. As adhesives for the heat-resistant layer, examples include acrylic resins, fluorinated resins, urethane resins, ethylene vinyl acetate resins, and epoxy resins.

[0047] Figure 6 This is a rear view of the stacked electrode body 20. As described above, tape 29 secures the second end 26e2. Figure 6 As shown, tape 29 is composed of a first tape 29a, a second tape 29b, and a third tape 29c intermittently arranged along the upper edge 26eU of the second end 26e2. In this embodiment, the upper edge 26eU of the second end 26e2 extends in the width direction X. Therefore, the first tape 29a, the second tape 29b, and the third tape 29c are arranged in the width direction X. In this embodiment, tape 29 is composed of the first tape 29a, the second tape 29b, and the third tape 29c, but the number of tapes constituting tape 29 is not particularly limited. In the following description, unless otherwise specified, "tape 29" refers to the first tape 29a, the second tape 29b, and the third tape 29c. Figure 5 As shown, in this embodiment, the upper end 29U of the tape 29 is positioned above the liquid surface 15a of the electrolyte 15. The thickness of the tape 29 is not particularly limited, but in this embodiment, it is approximately 50 μm. Figure 3As shown, in the portion of the laminated electrode body 20 where the adhesive tape 29 is fixed, the length in the thickness direction Y of the laminated electrode body 20 is relatively long. The portion where the first end 26e1, the second end 26e2, and the adhesive tape 29 overlap in the lamination direction Y is the thickest part of the laminated electrode body 20. In the following description, the portion where the first end 26e1, the second end 26e2, and the adhesive tape 29 overlap in the lamination direction Y of the laminated electrode body 20 will be referred to as the "thickest part".

[0048] Figure 5 This is a schematic diagram showing the interior of the main body 12 of the housing. (For example...) Figure 5 As shown, two stacked electrode bodies 20 are arranged in the thickness direction Y. When the pair of opposing side portions 12b of the housing body 12 are placed vertically, the upper edge 26eU of the second end 26e2 of the diaphragm 26, which is fixed by tape 29, is positioned below the electrolyte surface 15a on the outside of the stacked electrode bodies 20 within the housing body 12. The phrase "when the pair of opposing side portions 12b are placed vertically" refers to... Figure 5 As shown, this refers to the orientation of the housing body 12 when it is positioned such that one of the pair of narrow sides (here, the bottom part 12aa) is the lower side and the pair of side portions 12b, which are the wide sides, are placed approximately perpendicular to one of the pair of narrow sides. Here, the height of the electrolyte level 15a varies depending on the SOC (States of Charge) of the energy storage device 100. In this embodiment, when the SOC of the energy storage device 100 is 75% or higher, the upper edge 26e1 of the second end 26e2 is located below the electrolyte level 15a. That is, when the SOC of the energy storage device 100 is 75% or higher, the first end 26e1 and the second end 26e2 of the diaphragm 26, which is fixed by the tape 29, are positioned below the electrolyte level 15a. Furthermore, for ease of explanation, in Figure 5 In the diagram, a gap is shown between the stacked electrode body 20 and the side portion 12b, but the stacked electrode body 20 and the side portion 12b can also be in contact. Furthermore, the phrase "SOC of 75% or more" refers to a situation where the energy storage device 100 has an SOC of 75% or more when it is in a new condition or in a condition close to new.

[0049] like Figure 5As shown, the side 20Rr of the two stacked electrode bodies 20 on the side where the adhesive tape 29 is fixed is arranged facing the same side relative to the pair of opposing side portions 12b of the housing body 12. In this embodiment, the side 20Rr of each of the two stacked electrode bodies 20 is arranged facing the side portion 12bb. Alternatively, the side 20Rr of each of the two stacked electrode bodies 20 may also be arranged facing the side portion 12ba.

[0050] like Figure 2 As shown, the positive electrode plate 22 has a positive electrode tab 23 extending towards the first sealing plate 14 and connected to the positive terminal 30. Multiple positive electrode plates 22 each have a positive electrode tab 23. The positive electrode tab 23 is a positive current collector foil 22a (see reference). Figure 4 From the positive electrode active material layer 22b (reference) Figure 4 ) and negative electrode active material layer 24b (refer to) Figure 4 The portion extending from the overlapping area. The positive electrode tab 23 extends through the uncoated portion 22c (see reference). Figure 4 The positive electrode tab 23 is formed by overlapping. The positive electrode tab 23 is electrically connected to the positive terminal 30 via the positive current collector 32. The negative electrode plate 24 has a negative electrode tab 25 extending towards the second sealing plate 16 and connected to the negative terminal 40. Multiple negative electrode plates 24 each have a negative electrode tab 25. The negative electrode tab 25 is a negative current collector foil 24a (see reference). Figure 4 From the negative electrode active material layer 24b (refer to) Figure 4 ) and negative electrode active material layer 24b (refer to) Figure 4 The portion extending from the overlapping area. The negative electrode tab 25 extends through the uncoated portion 24c (refer to...). Figure 4 The electrodes are formed by overlapping. The negative electrode tab 25 is electrically connected to the negative terminal 40 via the negative electrode current collector 42. The positive electrode tab 23 is an example of the first electrode tab in this invention. The negative electrode tab 25 is an example of the second electrode tab in this invention.

[0051] Figure 3 The adhesive layer 28 shown is sandwiched between at least one of the positive electrode plate 22 and the negative electrode plate 24 and the separator 26, bonding the two together. This suppresses positional misalignment of the positive electrode plate 22 and the negative electrode plate 24. Furthermore, it suppresses lamination misalignment of the stacked electrode body 20. Figure 3 In the stacking direction Y, the two sides of the positive electrode plate 22 and the two sides of the negative electrode plate 24 are bonded to the opposing diaphragm 26 via the adhesive layer 28.

[0052] Typically, adhesive layer 28 is a layer containing adhesive in the highest possible mass proportion. Examples of adhesives include fluoropolymers, acrylic resins, urethane resins, ethylene vinyl acetate, and epoxy resins. The adhesive can be of the same type as the heat-resistant layer adhesive described above, or it can be different. Adhesive layer 28 may also further contain other materials (e.g., inorganic fillers).

[0053] The structure of the energy storage device 100 according to this embodiment has been described above. However, when the energy storage device 100 is charged and discharged, the positive electrode active material layer 22b (refer to...) Figure 4 ) and negative electrode active material layer 24b (refer to Figure 4 The stacked electrode body 20 expands and contracts due to the expansion and contraction of the electrolyte. When the stacked electrode body 20 expands, a portion of the electrolyte 15 impregnated within it is forced out. When the stacked electrode body 20 contracts, a portion of the electrolyte 15 is absorbed by it. If the thickness of the stacked electrode body 20 is uneven, the force applied to it during expansion and contraction will be different. If this repeated extrusion and absorption of the electrolyte 15 occurs, areas of insufficient electrolyte 15 may appear (so-called liquid drying). If liquid drying occurs, the battery characteristics of the energy storage device 100 deteriorate. The inventors of this application aim to suppress battery characteristic deterioration during repeated extrusion and absorption of the electrolyte 15.

[0054] Next, the electrolyte 15 inside the energy storage device 100 during charging and discharging will be described.

[0055] First, the charging of the energy storage device 100 will be explained. The energy storage device 100 is charged using existing, known methods. Figure 7 This is a schematic diagram showing the interior of the housing body 12 when the energy storage device 100 is being charged. When the energy storage device 100 is being charged, as described above, the positive electrode active material layer 22b (refer to...) Figure 4 ) and negative electrode active material layer 24b (refer to Figure 4 Expansion. As described above, the positive electrode plate 22 and the negative electrode plate 24 are stacked along the thickness direction Y. At this time, as... Figure 7 As shown, the positive electrode 22 and the negative electrode 24 are bent in a manner that extends outward toward the stacked electrode body 20. Therefore, the stacked electrode body 20 expands in a manner that extends in the thickness direction Y.

[0056] If the stacked electrode body 20 expands, it pushes against the pair of side portions 12b outward in the thickness direction Y. At this time, the stacked electrode body 20 experiences vertical resistance from the pair of side portions 12b. Here, the thickest part of the rear stacked electrode body 20 (hereinafter referred to as "rear stacked electrode body 20") faces the side portion 12bb, so the tape 29 contacts the side portion 12bb. In addition, the side portion 20F of the rear stacked electrode body 20 contacts the tape 29 of the front stacked electrode body 20 (hereinafter referred to as "front stacked electrode body 20"). Therefore, the rear stacked electrode body 20 is easily subjected to an inward force in the thickness direction Y near its thickest part. Here, "near the thickest part" refers to the area within the laminated electrode body 20 that includes at least one of the first end 26e1, the second end 26e2, or the tape 29. In this embodiment, "near the thickest part" refers to the position of the upper end 29U of the tape 29 in the vertical direction Z and the area below the upper end 29U of the tape 29 in the laminated electrode body 20.

[0057] The tape 29 of the front laminated electrode body 20 contacts the rear laminated electrode body 20. Furthermore, the most bulging portion of the side surface 20F of the front laminated electrode body 20 contacts the side surface 12ba. Here, the side surface 12ba contacts the side surface 20F near the center in the vertical direction Z. Therefore, in the front laminated electrode body 20, the side surface 20F is easily subjected to an inward force in the thickness direction Y near the center in the vertical direction Z, and the side surface 20Rr is easily subjected to an inward force in the thickness direction Y near its thickest portion. Furthermore, in the region of the laminated electrode body 20 above the tape 29, there is no first end 26e1, second end 26e2, or tape 29, therefore it is thinner in the thickness direction Y compared to the region of the laminated electrode body 20 excluding this region. Therefore, the region of the laminated electrode body 20 above the tape 29 experiences less inward force in the thickness direction Y.

[0058] If a force is applied to each of the two stacked electrode bodies 20 towards the inside in the thickness direction Y, the electrolyte 15 impregnated in the stacked electrode bodies 20 is forced out. Because the stacked electrode bodies 20 are pressed towards the inside in the thickness direction Y, the electrolyte 15 is forced out towards the outside in the width direction X. In this embodiment, because a force is applied near the thickest part of the stacked electrode body 20, the electrolyte 15 impregnated near the thickest part is easily forced out. The forced-out electrolyte 15 accumulates inside the housing body 12. More specifically, the forced-out electrolyte 15 accumulates in the lower part of the housing body 12 due to gravity. Therefore, as... Figure 2As shown, electrolyte 15 accumulates in the lower part of the housing body 12. At this time, electrolyte 15 also accumulates in the gaps GP on the right and left sides of the stacked electrode body 20 (see reference). Figure 2 In the laminated electrode body 20, the force applied to the inner side in the thickness direction Y is relatively small in the area above the tape 29, so it is difficult to expel the electrolyte 15 compared to the area near the thickest part.

[0059] Next, the discharge of the energy storage device 100 will be explained. The energy storage device 100 will be discharged, for example, when a vehicle (not shown) equipped with the energy storage device 100 is in motion. Figure 8 This is a schematic diagram showing the interior of the main body 12 of the casing when the energy storage device 100 is discharging. When the energy storage device 100 is discharged, as described above, the positive electrode active material layer 22b (refer to...) Figure 4 ) and negative electrode active material layer 24b (refer to Figure 4 Contraction. At this time, as... Figure 8 As shown, the positive electrode 22 and the negative electrode 24 are bent inwards towards the thickness direction Y. Therefore, the stacked electrode body 20 shrinks in the thickness direction Y.

[0060] If the stacked electrode body 20 contracts, the electrolyte 15 accumulated inside the housing body 12 is absorbed by the stacked electrode body 20. In this embodiment, the diaphragm 26 is installed such that it covers the positive electrode plate 22 and the negative electrode plate 24 in the thickness direction Y. Therefore, the positive electrode plate 22 and the negative electrode plate 24 are not covered by the diaphragm 26 in the width direction X. Therefore, the stacked electrode body 20 mainly absorbs the electrolyte 15 accumulated in the gap GP between the left and right sides of the stacked electrode body 20 (see reference). Figure 2 The electrolyte 15 is stored in the lower part of the housing body 12, and is absorbed from the lower part of the stacked electrode body 20. If the lower part of the stacked electrode body 20 cannot completely absorb the electrolyte 15, the electrolyte 15 is slowly absorbed by the upper part of the stacked electrode body 20.

[0061] Furthermore, the space between the first end 26e1 and the second end 26e2 is relatively narrow. Therefore, as the electrolyte 15 is absorbed by the upper part of the stacked electrode body 20, the electrolyte 15 entering between the first end 26e1 and the second end 26e2 is absorbed towards the positive electrode plate 22 and the negative electrode plate 24. That is, in Figure 8 As shown by the arrow, the electrolyte 15 disposed between the first end 26e1 and the second end 26e2 moves through the approximately right-angle portion of the first end 26e1 and the second end 26e2 due to capillary action, and moves toward the positive electrode plate 22 and the negative electrode plate 24.

[0062] As described above, in the energy storage device 100 of this embodiment, a stacked electrode body 20 and an electrolyte 15 are housed in the housing body 12. In the stacked electrode body 20, a positive electrode plate 22 and a negative electrode plate 24 are stacked, and a diaphragm 26 is sandwiched between the positive electrode plate 22 and the negative electrode plate 24 and folded back. The positive electrode plate 22 and the negative electrode plate 24 are located inside the cylindrical housing body 12 and are opposite to a pair of opposing side portions 12b, and the positive electrode plate 22 and the negative electrode plate 24 are arranged alternately. When the energy storage device 100 is charged and discharged, the electrolyte 15 impregnated in the stacked electrode body 20 is either expelled or absorbed mainly in the width direction X. That is, when the energy storage device 100 is charged and discharged, the electrolyte 15 is expelled into the gap GP, and the electrolyte 15 accumulated in the gap GP is absorbed by the stacked electrode body 20. The stacked electrode body 20 has a first end 26e1 and a second end 26e2. An adhesive tape 29 is fixed to the second end 26e2. Therefore, when the energy storage device 100 is charged, the stacked electrode body 20 expands, causing it to contact the pair of side portions 12b, resulting in a relatively large force near the thickest part of the stacked electrode body 20. Therefore, the electrolyte 15 is easily expelled from near the thickest part of the stacked electrode body 20. Furthermore, the upper edge 26e1 of the second end 26e2 is positioned below the liquid surface 15a of the electrolyte 15. Therefore, all or part of the area near the thickest part is immersed in the electrolyte 15. Therefore, if the stacked electrode body 20 contracts the electrolyte 15 after the electrolyte 15 is expelled from near the thickest part, the electrolyte 15 is easily absorbed from near the thickest part. That is, in the stacked electrode body 20, the portion where the electrolyte 15 is easily squeezed out during charging coincides with the portion where the electrolyte 15 is easily absorbed during discharging. Therefore, the occurrence of liquid drying in the stacked electrode body 20 can be suppressed. Thus, in the energy storage device 100, the degradation of battery characteristics caused by liquid drying during charging and discharging can be suppressed.

[0063] In the energy storage device 100 based on this embodiment, the upper end 29U of the tape 29 is positioned above the liquid surface 15a of the electrolyte 15. Therefore, the electrolyte 15 contained within the area clamped by the first end 26e1 and the second end 26e2 does not flow between the diaphragm 26 and the tape 29, but rather... Figure 8 As indicated by the middle arrow, the electrolyte 15 flows towards a position lower than the tape 29 and is absorbed by the positive electrode plate 22 and the negative electrode plate 24. Therefore, the absorbed electrolyte 15 circulates more easily within the stacked electrode body 20.

[0064] If the energy storage device 100 is based on this embodiment, then as follows Figure 6As shown, the tape 29 is intermittently arranged along the upper edge 26eU of the second end 26e2. Therefore, during charging of the energy storage device 100, the vertical resistance experienced by the housing body 12 differs at the second end 26e2 between the portion where the tape 29 is fixed and the portion where it is not fixed. That is, a greater force is applied to the portion where the tape 29 is fixed compared to the portion where it is not fixed. Consequently, when the laminated electrode body 20 expands and contracts due to charging and discharging of the energy storage device 100, a pressure difference is generated between the portion where the tape 29 is fixed and the portion where it is not fixed in the second end 26e2. This pressure difference becomes the driving force for the movement of the electrolyte 15 within the laminated electrode body 20. Therefore, due to this pressure difference, the electrolyte 15 easily expands within the laminated electrode body 20. Thus, it is possible to further suppress the drying out of the electrolyte within the energy storage device 100 due to charging and discharging.

[0065] In the energy storage device 100 based on this embodiment, the second end 26e2 is formed to be longer than the first end 26e1 in the vertical direction Z. Therefore, the second end 26e2 is fixed in such a way that it covers the first end 26e1 at a position above the upper end of the first end 26e1. As a result, loosening of the diaphragm 26 is suppressed.

[0066] In the energy storage device 100 based on this embodiment, a heat-resistant layer 26a is formed on the inner side of the second end 26e2. The second end 26e2 forms the outermost side of the diaphragm 26. Therefore, by forming a heat-resistant layer 26a on the inner side of the second end 26e2, even if a short circuit occurs inside the stacked electrode body 20, the burning-out situation can be suppressed.

[0067] In the case of the energy storage device 100 based on this embodiment, when the SOC of the energy storage device 100 is 75% or higher, the first end 26e1 and the second end 26e2 are positioned below the liquid surface 15a of the electrolyte 15. The electrolyte 15, which permeates the stacked electrode body 20, enters and exits the interior of the housing body 12 due to the charging and discharging of the energy storage device 100, so the height of the liquid surface 15a of the electrolyte 15 changes during charging and discharging. The inventors of this application have discovered that by positioning the first end 26e1 and the second end 26e2 below the liquid surface 15a of the electrolyte 15, the SOC of the energy storage device 100 is 75% or higher, allowing the electrolyte 15 to be absorbed from near the thickest part of the energy storage device 100, thereby suppressing liquid drying. Therefore, when the SOC of the energy storage device 100 is 75% or higher, one of the specific ways to obtain the effects of the present invention is by positioning the first end 26e1 and the second end 26e2 below the liquid surface 15a of the electrolyte 15.

[0068] In the energy storage device based on this embodiment, when the pair of side portions 12b are placed vertically, the upper edge 26eU of the second end 26e2 of each of the two stacked electrode bodies 20 is positioned below the liquid surface 15a of the electrolyte 15. Therefore, even when the energy storage device 100 has multiple stacked electrode bodies 20, it is still possible to suppress the drying out of the liquid in each stacked electrode body 20.

[0069] In the energy storage device 100 based on this embodiment, the side surfaces 20Rr of each of the two stacked electrode bodies 20 are arranged facing the side portion 12ba. Therefore, the direction in which the diaphragm 26 is folded back in the two stacked electrode bodies 20 is the same. Therefore, in the manufacture of the energy storage device 100, it is sufficient to prepare two stacked electrode bodies 20 with the diaphragm 26 folded back in the same direction. Therefore, the burden in manufacturing the energy storage device 100 can be reduced, and the productivity of the energy storage device 100 can be improved.

[0070] In the energy storage device 100 based on this embodiment, the positive electrode tab 23 extends towards the first sealing plate 14 and is connected to the positive terminal 30. The positive terminal 30 is disposed on the first sealing plate 14. The negative electrode tab 25 extends towards the second sealing plate 16 and is connected to the negative terminal 40. The negative terminal 40 is disposed on the second sealing plate 16. Therefore, in this embodiment, the first sealing plate 14, the positive terminal 30, the positive electrode tab 23, the second sealing plate 16, the negative terminal 40, and the negative electrode tab 25 are arranged in the width direction X. By arranging them in the width direction X, the vertical length Z of the stacked electrode body 20 can be made more uniform. As a result, the vertical length Z of the housing body 12 can be made close to the vertical length Z of the stacked electrode body 20, and the filling rate of the stacked electrode body 20 in the housing body 12 can be made higher. As a result, the extruded electrolyte 15 is more easily accumulated in the gap GP. The electrolyte 15 stored in the gap GP is absorbed when the energy storage device 100 discharges. Therefore, it is relatively easy to circulate the electrolyte 15 between the inside and outside of the stacked electrode body 20.

[0071] The energy storage device 100 according to the first embodiment has been described above. However, the first embodiment described above is only an example, and the present invention can be implemented in various other ways.

[0072] <Second Embodiment>

[0073] Figure 9 This is a schematic diagram showing the interior of the energy storage device 100A according to the second embodiment. In the following description of the second embodiment, components that perform the same functions as in the first embodiment are referred to using the same reference numerals as in the first embodiment. Furthermore, repeated descriptions will be omitted or simplified. The same applies to the third and fourth embodiments described later.

[0074] like Figure 9 As shown, in the second embodiment, the upper end 29U of the tape 29 is positioned below the liquid surface 15a of the electrolyte 15.

[0075] When charging the energy storage device 100A, as in the first embodiment, the area near the thickest part of the laminated electrode body 20 experiences a greater force. Therefore, the electrolyte 15 impregnated near the thickest part of the laminated electrode body 20 is forced out. Furthermore, since the upper end 29U of the tape 29 is positioned below the liquid surface 15a of the electrolyte 15, the area near the thickest part of the laminated electrode body 20 is located below the liquid surface 15a of the electrolyte 15. When discharging the energy storage device 100, as in the first embodiment, the laminated electrode body 20 contracts, thereby absorbing the electrolyte 15.

[0076] In the second embodiment described above, the upper end 29U of the tape 29 is positioned below the liquid surface 15a of the electrolyte 15. Here, the laminated electrode body 20 bears pressure from the electrolyte 15 at a position below the liquid surface 15a of the electrolyte 15. In this embodiment, since the upper end 29U is positioned below the liquid surface 15a of the electrolyte 15, a relatively large portion of the laminated electrode body 20 is immersed in the electrolyte 15. Therefore, the pressure from the electrolyte 15 is applied to a relatively large area of ​​the laminated electrode body 20. As a result, it is easier to push the electrolyte 15 immersed in the laminated electrode body 20 upwards. This suppresses the possibility of the electrolyte 15 drying out inside the laminated electrode body 20.

[0077] <Third Embodiment>

[0078] Figure 10 This is a schematic diagram showing the interior of the energy storage device 100B according to the third embodiment. Figure 10As shown, a stacked electrode body 20B and a stacked electrode body 21B are housed inside the housing 10. The stacked electrode body 20B is positioned forward of the stacked electrode body 21B. The side of the stacked electrode body 20B to which the adhesive tape 29 is fixed is designated as side 20BF. The side of the stacked electrode body 20B opposite to side 20BF ​​in the thickness direction Y is designated as side 20Br. Similarly, the side of the stacked electrode body 21B to which the adhesive tape 29 is fixed is designated as side 21Br. The side of the stacked electrode body 21B opposite to side 21Br in the thickness direction Y is designated as side 21BF. Side 20BF ​​is located on the front surface of the stacked electrode body 20B, and side 20Br is located on the rear surface of the stacked electrode body 20B. Side 21BF is located on the front surface of the stacked electrode body 20B, and side 21Br is located on the rear surface of the stacked electrode body 21B. Therefore, the folding method of the separator 26 in the stacked electrode body 20B is different from that in the stacked electrode body 21B. The stacked electrode body 20B is formed by folding the separator 26 with the first end 26e1 and the second end 26e2 positioned in front of the positive electrode plate 22 and the negative electrode plate 24. The stacked electrode body 21B is formed by folding the separator 26 with the first end 26e1 and the second end 26e2 positioned behind the positive electrode plate 22 and the negative electrode plate 24.

[0079] In the third embodiment, the sides of the laminated electrode body 20, which are positioned opposite to the pair of opposing side portions 12b of the housing body 12, where the adhesive tape 29 is fixed, are respectively arranged facing the side portion 12b of the housing body 12. More specifically, the side portion 20BF ​​of the laminated electrode body 20B is arranged facing the side portion 12ba, and the side portion 21Br of the laminated electrode body 21B is arranged facing the side portion 12bb.

[0080] When the energy storage device 100B is charged, the stacked electrode bodies 20B and 21B expand in the thickness direction Y. The tape 29 fixed to the side surface 20BF ​​of the stacked electrode body 20B contacts the side surface 12ba, receiving vertical resistance from the side surface 12ba. Similarly, the tape 29 fixed to the side surface 21Br of the stacked electrode body 21B contacts the side surface 12bb, receiving vertical resistance from the side surface 12bb. At this time, the side surface 20Br of the stacked electrode body 20B contacts the side surface 21BF of the stacked electrode body 21B, pressing against each other. The electrolyte 15 impregnated in the stacked electrode bodies 20B and 21B is then forced out.

[0081] Based on the third embodiment described above, the tape 29 of the laminated electrode body 20B and the tape 29 of the laminated electrode body 21B respectively bear vertical resistance from the pair of opposing side portions 12b. Therefore, the laminated electrode bodies 20B and 21B are arranged such that they easily bear force from the pair of opposing side portions 12b near their thickest parts. As a result, the amount of electrolyte 15 extruded and absorbed is relatively large, and electrolyte 15 circulation easily occurs inside and outside the laminated electrode bodies 20B and 21B. Therefore, the phenomenon of electrolyte 15 drying out inside and outside the laminated electrode bodies 20B and 21B can be suppressed.

[0082] <Fourth Implementation>

[0083] Figure 11 This is a schematic diagram showing the interior of the energy storage device 100C according to the fourth embodiment. (As shown...) Figure 11 As shown, a stacked electrode body 20C and a stacked electrode body 21C are housed inside the housing 10. The stacked electrode body 20C is positioned forward of the stacked electrode body 21C. The side of the stacked electrode body 20C where the adhesive tape 29 is fixed is designated as side 20Cr. The side of the stacked electrode body 20C opposite to side 20Cr in the thickness direction Y is designated as side 20CF. Similarly, the side of the stacked electrode body 21C where the adhesive tape 29 is fixed is designated as side 21CF. The side of the stacked electrode body 21C opposite to side 21CF in the thickness direction Y is designated as side 21Cr. Side 20Cr is located on the rear surface of the stacked electrode body 20C, and side 20CF is located on the front surface of the stacked electrode body 20C. Side 21CF is located on the front surface of the stacked electrode body 21C, and side 21Cr is located on the rear surface of the stacked electrode body 21C. Therefore, the folding methods of the separator 26 in the stacked electrode body 20C and the stacked electrode body 21C are different. The stacked electrode body 20C is formed by folding the separator 26 with the first end 26e1 and the second end 26e2 positioned behind the positive electrode plate 22 and the negative electrode plate 24. The stacked electrode body 21C is formed by folding the separator 26 with the first end 26e1 and the second end 26e2 positioned in front of the positive electrode plate 22 and the negative electrode plate 24.

[0084] In the fourth embodiment, the side of the laminated electrode body 20C and the laminated electrode body 21C where the adhesive tape 29 is fixed faces the side opposite to the pair of opposing side portions 12b of the housing body 12. More specifically, the side portion 20Cr of the laminated electrode body 20C is disposed on the side opposite to the side portion 12ba in the thickness direction Y. The side portion 21CF of the laminated electrode body 21C is disposed on the side opposite to the side portion 12bb in the thickness direction Y. Therefore, the side portions 20Cr and 21CF are opposite to each other.

[0085] When the energy storage device 100C is charged, the stacked electrode bodies 20C and 21C expand in the thickness direction Y, causing the side surface 20CF of the stacked electrode body 20C to contact the side surface portion 12ba, thereby bearing vertical resistance from the side surface portion 12ba. Additionally, the side surface 21Cr of the stacked electrode body 21C contacts the side surface portion 12bb, bearing vertical resistance from the side surface portion 12bb. At this time, the tape 29 of the stacked electrode body 20C contacts the tape 29 of the stacked electrode body 21C, applying force near the thickest part of the stacked electrode bodies 20C and 21C in the thickness direction Y. Therefore, the electrolyte 15 impregnated in the stacked electrode bodies 20C and 21C is expelled.

[0086] Based on the fourth embodiment described above, the stacked electrode body 20C receives vertical resistance from the side portion 12ba, and the stacked electrode body 21C receives vertical resistance from the side portion 12bb. Therefore, pressing the tape 29 of the stacked electrode body 20C and the tape 29 of the stacked electrode body 21C in the thickness direction Y results in pressure near the thickest part of both the stacked electrode bodies 20C and 21C. Furthermore, since the tape 29 is not fixed to the side portion 20CF of the stacked electrode body 20C and the side portion 21Cr of the stacked electrode body 21C, the side portions 20CF and 21Cr are relatively flat. Therefore, at the side portions 20CF and 21Cr, the force is less likely to deviate in the vertical direction Z. Therefore, when the stacked electrode bodies 20C and 21C expand and contact the pair of side portions 12b, the vertical resistance received from the pair of side portions 12b is less likely to be distributed in directions other than the thickness direction Y. Therefore, the amount of electrolyte 15 extruded from the stacked electrode bodies 20C and 21C, and the amount of electrolyte 15 absorbed by the stacked electrode bodies 20C and 21C, are relatively large. Electrolyte 15 circulation easily occurs inside and outside the stacked electrode bodies 20C and 21C. Therefore, the phenomenon of electrolyte 15 drying out inside and outside the stacked electrode bodies 20C and 21C can be suppressed.

[0087] The invention disclosed herein has been described above in various ways. Unless otherwise specified, the embodiments described herein are not intended to limit the invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and unless special problems arise, the constituent elements and the processes mentioned herein can be appropriately omitted or appropriately combined.

[0088] As described above, the disclosures contained in the following items are included in this specification.

[0089] Item 1:

[0090] A secondary battery, comprising:

[0091] An electrode body comprising a diaphragm, a plurality of first electrode plates, and a plurality of second electrode plates having a polarity different from that of the first electrode plates;

[0092] Electrolyte;

[0093] The housing body is cylindrical and houses the electrode body and the electrolyte.

[0094] A first sealing plate, which is installed at the opening on the first side of the aforementioned housing body; and

[0095] The second sealing plate is installed at the opening on the second side of the aforementioned housing body.

[0096] in,

[0097] The aforementioned shell body has a pair of opposing side portions.

[0098] The aforementioned plurality of first electrode plates and the aforementioned plurality of second electrode plates are located inside the aforementioned housing body and are opposed to the aforementioned pair of opposing side portions, and the aforementioned first electrode plates and the aforementioned second electrode plates are arranged alternately.

[0099] The aforementioned diaphragm is strip-shaped and is sequentially folded back between the first electrode plate and the second electrode plate, thereby being disposed between the first electrode plate and the second electrode plate.

[0100] The first end of the aforementioned diaphragm is disposed on the outer periphery of the aforementioned electrode body, which is formed by alternating opposition of the aforementioned plurality of first electrode plates and the aforementioned plurality of second electrode plates.

[0101] The second end of the aforementioned diaphragm is disposed on the outer periphery of the electrode body, which is formed by alternating opposition of the plurality of first electrode plates and the plurality of second electrode plates, and is fixed to the outer periphery of the electrode body by adhesive tape in a manner that overlaps with the outer side of the first end.

[0102] When the pair of opposing side portions of the housing body are placed vertically, the upper edge of the second end of the diaphragm, which is fixed by the tape, is positioned below the electrolyte surface on the outside of the electrode body inside the housing body.

[0103] Item 2:

[0104] In the secondary battery described in item 1, the upper end of the tape is positioned above the surface of the electrolyte.

[0105] Item 3:

[0106] In the secondary battery described in item 1, the upper end of the tape is positioned below the surface of the electrolyte.

[0107] Item 4:

[0108] In any of the secondary batteries described in items 1 to 3, the aforementioned tape is composed of a plurality of tapes intermittently arranged along the upper edge of the aforementioned second end.

[0109] Item 5:

[0110] In any of the secondary batteries described in items 1 to 4, at the portion of the diaphragm that is fixed to the outer periphery of the electrode body by the tape, the second end of the diaphragm is longer than the first end.

[0111] Item 6:

[0112] In any of the secondary batteries described in items 1 to 5, at the portion of the electrode body that is fixed to the outer periphery by the tape, the second end of the diaphragm has a heat-resistant layer formed on the inner side of the electrode body.

[0113] Item 7:

[0114] In any of the secondary batteries described in items 1 to 6, when the SOC is 75% or higher, and the pair of opposing side portions of the main body of the casing are placed vertically, the first end and the second end of the diaphragm, which are fixed by the tape, are positioned below the surface of the electrolyte on the outside of the electrode body.

[0115] Item 8:

[0116] In any of the secondary batteries described in items 1 to 7, multiple electrode bodies are arranged in an opposing manner along the pair of opposing side portions of the main body of the casing.

[0117] When the pair of opposing side portions of the housing body are placed vertically, the upper edge of the second end of the diaphragm of each of the plurality of electrodes, which is fixed by the tape, is positioned below the electrolyte surface on the outside of the electrode body inside the housing body.

[0118] Item 9:

[0119] In any of the secondary batteries described in items 1 to 8, the side of the electrode body to which the tape is fixed is arranged such that the pair of opposing side portions of the housing body face the same side.

[0120] Item 10:

[0121] In any of the secondary batteries described in items 1 to 8, the side of the electrode body on which the tape is fixed is disposed at a position opposite to the pair of opposing side portions of the housing body and is respectively disposed in such a way that it faces the side portion of the housing body.

[0122] Item 11:

[0123] In any of the secondary batteries described in items 1 to 8, the side of the electrode body to which the tape is fixed faces the side opposite to the pair of opposing side portions of the main body of the casing.

[0124] Item 12:

[0125] The secondary battery described in any one of items 1 to 11 has the following characteristics:

[0126] The first terminal disposed on the first sealing plate mentioned above; and

[0127] The second terminal is located at the second sealing plate mentioned above.

[0128] Each of the aforementioned first electrode plates has a first electrode tab extending toward the first sealing plate and connected to the first terminal.

[0129] Each of the aforementioned second electrode plates has a second electrode tab extending toward the aforementioned second sealing plate and connected to the aforementioned second terminal.

Claims

1. A secondary battery, comprising: An electrode body comprising a diaphragm, a plurality of first electrode plates, and a plurality of second electrode plates having a polarity different from that of the first electrode plates; Electrolyte; The housing body is cylindrical and houses the electrode body and the electrolyte. A first sealing plate, which is installed at an opening on a first side of the housing body; as well as A second sealing plate, which is installed at the opening on the second side of the housing body. The secondary battery is characterized in that... The main body of the housing has a pair of opposing side portions. The plurality of first electrode plates and the plurality of second electrode plates are positioned inside the housing body opposite the pair of opposing side portions, and the first electrode plates and the second electrode plates are arranged alternately. The diaphragm is strip-shaped and is sequentially folded back between the first electrode plate and the second electrode plate, thereby being disposed between the first electrode plate and the second electrode plate. The first end of the diaphragm is disposed on the outer periphery of the electrode body, which is formed by alternating opposition of the plurality of first electrode plates and the plurality of second electrode plates. The second end of the diaphragm is disposed on the outer periphery of the electrode body, which is formed by alternating opposition of the plurality of first electrode plates and the plurality of second electrode plates, and is fixed to the outer periphery of the electrode body by adhesive tape in a manner that overlaps with the outer side of the first end. When the pair of opposing side portions of the housing body are placed vertically, the upper edge of the second end of the diaphragm, which is fixed by the tape, is positioned below the electrolyte surface on the outside of the electrode body inside the housing body.

2. The secondary battery according to claim 1, characterized in that, The upper end of the tape is positioned above the surface of the electrolyte.

3. The secondary battery according to claim 1, characterized in that, The upper end of the tape is positioned below the surface of the electrolyte.

4. The secondary battery according to claim 1, characterized in that, The tape is composed of a plurality of tapes intermittently arranged along the upper edge of the second end.

5. The secondary battery according to claim 1, characterized in that, At the portion of the diaphragm that is fixed to the outer periphery of the electrode body by the tape, the second end of the diaphragm is longer than the first end.

6. The secondary battery according to claim 1, characterized in that, At the portion of the electrode body that is fixed to the outer periphery by the tape, the second end of the diaphragm has a heat-resistant layer formed on the inner side of the electrode body.

7. The secondary battery according to claim 1, characterized in that, When the SOC is above 75%, and the pair of opposing side portions of the housing body are placed vertically, the first end and the second end of the diaphragm, which are fixed by the tape, are positioned below the electrolyte surface on the outside of the electrode body.

8. The secondary battery according to claim 1, characterized in that, The electrode bodies are arranged in a plurality of opposite positions along the one pair of opposite side portions of the housing body. When the pair of opposing side portions of the housing body are placed vertically, the upper edge of the second end of the diaphragm of each of the plurality of electrodes, which is fixed by the tape, is positioned below the electrolyte surface on the outside of the electrode inside the housing body.

9. The secondary battery according to claim 1, characterized in that, The sides of the electrode body to which the tape is fixed are each arranged such that they face the same side relative to the pair of opposing side portions of the housing body.

10. The secondary battery according to claim 1, characterized in that, The sides of the electrode bodies, in which the tape is fixed, are located opposite the pair of opposing side portions of the housing body and are respectively arranged facing the side portions of the housing body.

11. The secondary battery according to claim 1, characterized in that, The side of the electrode body to which the tape is fixed faces the side opposite to the pair of opposing side portions of the housing body.

12. The secondary battery according to claim 1, characterized in that, have: The first terminal of the first sealing plate is disposed thereon; and The second terminal is located at the second sealing plate. Each of the plurality of first electrode plates has a first electrode tab extending toward the first sealing plate and connected to the first terminal. Each of the plurality of the second electrode plates has a second electrode tab extending toward the second sealing plate and connected to the second terminal.

Images