Rechargeable battery

Abstract

A rechargeable battery includes: an electrode assembly including a first winding portion and a second winding portion connected by a connection portion, the first winding portion and the second winding portion being formed by winding at each of both ends of a stack of a first electrode plate, a first separator, a second electrode plate, and a second separator; and a case accommodating the electrode assembly, in which the case includes: flat sides facing each other at both sides of the case in a width direction; and curved sides at both ends of the case in the length direction, and the flat side and the first and second winding portions surround an electrolyte solution accommodating space between the flat side and the first and second winding portions.

Description

Technical Field

[0001] Embodiments relate to a rechargeable battery. Background Art

[0002] Unlike primary batteries, rechargeable batteries are batteries that are repeatedly charged and discharged. Small rechargeable batteries can be used in portable small electronic devices (such as mobile phones, laptops or portable cameras). Large capacity and high density rechargeable batteries can be used to store motor drive power or energy for hybrid vehicles and electric vehicles.

[0003] A rechargeable battery may include an electrode assembly for charging and discharging, a case for accommodating the electrode assembly and an electrolyte, a cap plate connected to an opening of the case, and an electrode terminal for leading the electrode assembly out of the cap plate. The electrode assembly may be formed into a core type formed by winding an electrode plate and a separator, or may be formed into a stack type formed by stacking an electrode plate and a separator. Summary of the invention

[0004] An embodiment can be achieved by providing a rechargeable battery, which includes: an electrode assembly, including a first winding portion and a second winding portion connected by a connecting portion, the first winding portion and the second winding portion being formed by winding at each of the two ends of a stack of a first electrode plate, a first separator, a second electrode plate and a second separator; and a shell that accommodates the electrode assembly, wherein the shell includes: flat sides facing each other at both sides of the shell in the width direction; and curved sides at both ends of the shell in the length direction, and the flat sides and the first winding portion and the second winding portion surround an electrolyte accommodating space between the flat sides and the first winding portion and the second winding portion.

[0005] The connection portion may be a portion of the stack of the first electrode plate, the first separator, the second electrode plate, and the second separator.

[0006] The first winding portion and the second winding portion may have a cylindrical shape, and the curved side of the shell may include a first arc side and a second arc side, wherein the first arc side faces one side of the first winding portion and the second arc side faces one side of the second winding portion.

[0007] The electrolyte containing space may be surrounded by a first side of the first winding portion, a second side of the second winding portion, and the flat side, each of the first winding portion and the second winding portion having a cylindrical shape, and the flat side faces the first side of the first winding portion and the second side of the second winding portion.

[0008] The first winding portion and the second winding portion may be wound in the same direction, and the electrolyte accommodation space may have a symmetrical structure between the flat sides of the case.

[0009] The first winding portion and the second winding portion may have a racetrack column shape, and the curved side of the shell may include: a 1-1 quarter circle side and a 1-2 quarter circle side, respectively facing two corners of the first winding portion; and a 2-1 quarter circle side and a 2-2 quarter circle side, respectively facing two corners of the second winding portion.

[0010] The electrolyte holding space may be surrounded by a first side of the first winding portion, a second side of the second winding portion, and the flat side, each of the first winding portion and the second winding portion having a racetrack column shape, and the flat side faces the first side of the first winding portion and the second side of the second winding portion.

[0011] The flat side may include a 1-1 flat side and a 1-2 flat side, the shell may further include a 2-1 flat side and a 2-2 flat side at the two ends of the shell in the length direction, the first winding portion and the second winding portion may be wound in the same direction, and the electrolyte holding space may have a symmetrical structure between the 1-1 flat side and the 1-2 flat side.

[0012] The electrode assembly may further include a third winding portion between the first winding portion and the second winding portion, the third winding portion having a cylindrical shape, the connecting portion may include a 3-1 connecting portion connecting the first winding portion and the third winding portion and a 3-2 connecting portion connecting the third winding portion and the second winding portion, and the curved side of the shell may include a first arc side and a second arc side, the first arc side facing a side of the first winding portion, and the second arc side facing a side of the second winding portion.

[0013] The electrolyte holding space can be surrounded by a first side of the first winding portion opposite to the one side of the first winding portion, a third side of the third winding portion, a fourth side of the third winding portion, a second side of the second winding portion opposite to the one side of the second winding portion, and the flat side, each of the first winding portion, the second winding portion, and the third winding portion having a cylindrical shape, and the flat side faces the first side of the first winding portion, the third side of the third winding portion, the fourth side of the third winding portion, and the second side of the second winding portion.

[0014] The first winding portion and the second winding portion may be wound in opposite directions, and the third winding portion may be formed by winding the stacked body in two layers, and may be wound in the same direction as the first winding portion.

[0015] The electrode assembly may further include a third winding portion between the first winding portion and the second winding portion, the first winding portion, the third winding portion and the second winding portion may each have a racetrack column shape, and the curved side of the shell may include: a 1-1 quarter circle side and a 1-2 quarter circle side, respectively facing two corners of the first winding portion; and a 2-1 quarter circle side and a 2-2 quarter circle side, respectively facing two corners of the second winding portion.

[0016] The electrolyte holding space may be surrounded by a first side of the first winding portion, a third side of the third winding portion, a fourth side of the third winding portion, a second side of the second winding portion, and the flat side, each of the first winding portion, the second winding portion, and the third winding portion having a runway column shape, and the flat side facing the first side of the first winding portion, the third side of the third winding portion, the fourth side of the third winding portion, and the second side of the second winding portion.

[0017] The flat side may include a 1-1 flat side and a 1-2 flat side, the shell may further include a 2-1 flat side and a 2-2 flat side at the two ends of the shell in the length direction, the first winding portion and the second winding portion may be wound in opposite directions, and the third winding portion may be formed by winding the stack in two layers and may be wound in the same direction as the first winding portion.

[0018] The rechargeable battery may further include: a cap plate closing and sealing the opening of the case; and an electrode terminal connected to the second uncoated area of ​​the second electrode plate and mounted in an insulating structure on the cap plate, and wherein the case may be connected to the first uncoated area of ​​the first electrode plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Features will be apparent to those skilled in the art by describing exemplary embodiments in detail with reference to the accompanying drawings, in which:

[0020] Figure 1 is a perspective view of a rechargeable battery according to a first embodiment of the present disclosure.

[0021] Figure 2 It is along Figure 1 A cross-sectional view taken along line II-II in FIG.

[0022] Figure 3 is an exploded perspective view of a stack including a first separator, a first electrode plate, a second separator, and a second electrode plate forming an electrode assembly.

[0023] Figure 4 It is shown Figure 3 A side view of the winding direction of the stack.

[0024] Figure 5 is along Figure 4 Side view of the electrode assembly wound in the winding direction.

[0025] Figure 6 yes Figure 5 A cross-sectional view of the state of the electrode assembly in the casing.

[0026] Figure 7 is a cross-sectional view of a state in which an electrode assembly in a rechargeable battery according to a second embodiment of the present disclosure is in a case.

[0027] Figure 8 is a side view showing a winding direction of a stacked body forming an electrode assembly of a rechargeable battery according to a third embodiment of the present disclosure.

[0028] Fig. 9 yes Figure 8 A cross-sectional view of the state of the electrode assembly in the casing.

[0029] Fig.10 is a cross-sectional view of a state in which an electrode assembly in a rechargeable battery according to a fourth embodiment of the present disclosure is in a case.

[0030] Description of Reference Numerals

[0031] 1, 2, 3, 4: Rechargeable battery 10, 50: Electrode assembly

[0032] 11: stack 14: exhaust plate

[0033] 15: Electrolyte injection port 16: Plug

[0034] 17: Nut 20, 60: Housing

[0035] 21, 22: Flat side 23: Curved side

[0036] 30: Cover plate 40: Electrode terminal

[0037] 63: curved surface 70: electrode assembly

[0038] 73: Connecting part 80: Housing

[0039] 81, 82: Flat side 83: Curved side

[0040] 85: Mandrel 90: Electrode assembly

[0041] 100: housing 111: first winding portion

[0042] 112: Second winding portion 113: Connecting portion

[0043] 150: Shell 163: Curved side

[0044] 231: First arc side 232: Second arc side

[0045] 311: 1-1 Quarter circle side 312: 1-2 Quarter circle side

[0046] 321: 2-1 quarter circle side 322: 2-2 quarter circle side

[0047] 511: first winding portion 512: second winding portion

[0048] 713: third winding section 731: 1-3 connecting section

[0049] 732: 3-2 connection part 831: first arc side

[0050] 832: Second arc side 913: Third winding portion

[0051] 1011, 1511: 1-1 flat side 1012, 1512: 1-2 flat side 1021, 1521: 2-1 flat side 1022, 1522: 2-2 flat side E1: first electrode plate E1a, E2a: coating area E1b, E2b: Uncoated area E2: Second electrode plate ES, ES2: electrolyte storage space ES3, ES4: electrolyte storage space H: Terminal hole S1: First diaphragm

[0052] S2: Second diaphragm S11: First side

[0053] S12, S22: second side S21, S31: first side S23, S33: third side S24, S34: fourth side DETAILED DESCRIPTION

[0054] In the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being "on" another layer or element, it can be directly on the other layer or element, or intervening layers may also be present. Additionally, it will be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0055] Hereinafter, the present disclosure will be more fully described with reference to the accompanying drawings, in which embodiments of the present disclosure are shown. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways, all without departing from the scope of the present disclosure. The figures and descriptions are to be regarded as illustrative and non-restrictive in nature. Throughout the specification, the same reference numerals refer to the same elements.

[0056] Figure 1 is a perspective view of a rechargeable battery according to a first embodiment of the present disclosure. Figure 2 It is along Figure 1 A cross-sectional view taken along line II-II in FIG. Figure 3 is an exploded perspective view of a stack including a first separator, a first electrode plate, a second separator, and a second electrode plate forming an electrode assembly. Figure 4 It is shown Figure 3 A side view of the winding direction of the stack.

[0057] refer to Figures 1 to 4 The rechargeable battery 1 of the first embodiment may include an electrode assembly 10 that performs charge and discharge, a case 20 that accommodates the electrode assembly 10 and an electrolyte, a cap plate 30 that closes and seals an opening of the case 20, and an electrode terminal 40 mounted on the cap plate 30 using an insulating structure.

[0058] Figure 5 is along Figure 4 A side view of an electrode assembly wound in the winding direction. Figures 1 to 5 The electrode assembly 10 may include a first wound portion 111 and a second wound portion 112 formed by winding in the same (eg, clockwise) direction at both ends of the stack body 11 .

[0059] In one embodiment, the first winding portion 111 may be wound upward in a clockwise direction, and the second winding portion 112 may be wound downward in a clockwise direction. The first winding portion 111 and the second winding portion 112 may be formed by winding the stack 11 with a winding mandrel, and while performing the winding, the two winding mandrels may move toward each other to reduce the gap therebetween.

[0060] The first and second wound portions 111 and 112 may each be formed in a core state, and may be connected to each other through a connection portion 113 to electrically form one electrode assembly 10 .

[0061] The stack 11 may be formed by stacking a first separator S1, a first electrode plate E1, a second separator S2, and a second electrode plate E2, and refers to a state before being wound into the electrode assembly 10. The first electrode plate E1 and the second electrode plate E2 may include coated areas E1a and E2a (in which an active material is coated on both sides of a substrate formed of a thin metal plate) and uncoated areas E1b and E2b (in which the substrate is exposed without being coated with an active material).

[0062] In one embodiment, the first electrode plate E1 may be a positive electrode formed by coating a positive active material on a substrate made of aluminum (Al) foil, and the second electrode plate E2 may be a negative electrode formed by coating a negative active material on a substrate made of copper (Cu) foil.

[0063] The uncoated region E1b of the first electrode plate E1 and the uncoated region E2b of the second electrode plate E2 may be located at two winding axial ends ( Figure 1 and Figure 2 The uncoated region E1b of the first electrode plate E1 may be welded to the bottom of the housing 20. In one embodiment, the housing 20 may contain the electrode assembly 10 and the electrolyte, and may be connected to the first uncoated region E1b of the first electrode plate E1. In one embodiment, the uncoated region E1b of the first electrode plate E1 may be welded to the current collecting plate, and the current collecting plate may be directly welded to the bottom of the housing.

[0064] The uncoated region E2b of the second electrode plate E2 may be welded to the current collecting plate 13, and the current collecting plate 13 may be welded to the electrode terminal 40. The electrode terminal 40 may be in the terminal hole H of the cap plate 30 with a gasket 41 therebetween. In one embodiment, the electrode terminal 40 may be a bolt and may be fastened and fixed to the cap plate 30 with a nut 17. In one embodiment, the electrode terminal may be formed as a rivet type.

[0065] In one embodiment, the first electrode plate and the second electrode plate may not have an uncoated area at one end of the first electrode plate and the second electrode plate in the width direction, and the uncoated area may be located at at least one of the two ends of the first electrode plate and the second electrode plate and the connecting portion 113 in the length direction, respectively, and the wiring tab may be welded to the uncoated area to be formed.

[0066] The cap plate 30 may include a vent plate 14 and an electrolyte injection port 15. If the internal pressure of the rechargeable battery will increase and an incident will occur, the vent plate 14 may help prevent the explosion of the rechargeable battery 1 by releasing the internal pressure. The electrolyte injection port 15 may be sealed with a plug 16 after injecting the electrolyte.

[0067] Figure 6 It is shown Figure 5 A cross-sectional view of the electrode assembly in the housing. Figure 5 and Figure 6 The housing 20 may include a pair of flat surfaces or flat sides 21 and 22 facing each other on the sides (e.g., both sides) in the width direction of the cap plate 30 (i.e., the same direction as the width direction of the housing 20) and a curved surface or curved side (e.g., a pair of curved sides) 23 at the ends (e.g., both ends) in the length direction of the cap plate 30 (i.e., the same direction as the length direction of the housing 20). The housing 20 including the flat sides 21 and 22 may establish or include the electrolyte accommodation space ES between the first winding portion 111 and the second winding portion 112.

[0068] The pair of curved sides 23 may help reduce the overall space or volume of the case 20 that accommodates the electrode assembly 10. The pair of flat sides 21 and 22 may help secure or define the electrolyte accommodation space ES with the first and second winding portions 111 and 112 therebetween, thereby increasing the amount of electrolyte that can be accommodated in the case 20 even though the overall volume of the case 20 may be reduced.

[0069] The connection portion 113 may be formed of a stack 11 of the first electrode plate E1, the first separator S1, the second electrode plate E2, and the second separator S2. In one embodiment, the tab may be connected to the connection portion 113 by welding.

[0070] In one embodiment, the first winding portion 111 and the second winding portion 112 may be formed as, for example, a cylinder. The curved side 23 of the housing 20 may include a first semicircular side or a first arc side 231 that accommodates or faces one side (e.g., an arc side) of the first winding portion 111 and a second semicircular side or a second arc side 232 that accommodates or faces one side (e.g., an arc side) of the second winding portion 112. In one embodiment, the curved side 23 of the housing 20 may have an arc shape (e.g., a concave arc shape) that is substantially complementary to the arc shape (e.g., a convex arc shape) of the first winding portion 111 and the second winding portion 112.

[0071] The electrolyte holding space ES can be set or surrounded by the first side S11 of the first winding portion 111 and the second side S12 of the second winding portion 112 (which can be formed by a cylinder) and the flat sides 21 and 22 facing the first side S11 and the second side S12, or between them, thereby increasing the injection or holding amount of the electrolyte.

[0072] The first winding portion 111 and the second winding portion 112 may be wound in the same direction and may help form or provide an electrolyte accommodation space ES having a symmetrical structure or having a symmetrical structure between the pair of flat sides 21 and 22 in the case 20. The symmetrical electrolyte accommodation space ES may make the injection amount of the electrolyte impregnated on the electrode assembly 10 uniform.

[0073] Many exemplary variations and embodiments of the present disclosure are described below. Compared to the first embodiment, repeated descriptions of the same configurations may be omitted, and descriptions of different configurations may be provided.

[0074] Figure 7 is a cross-sectional view of a state in which an electrode assembly in a rechargeable battery according to a second embodiment of the present disclosure is in a case. Figure 7 In the electrode assembly 50 of the rechargeable battery 2 of the second embodiment, the first winding portion 511 and the second winding portion 512 may be formed as a racetrack-shaped column. A racetrack-shaped column refers to a three-dimensional shape that has an oval shape with semicircles formed on both sides and the semicircles on both sides connected by straight lines when viewed from a plan view, and has a quadrilateral shape when viewed from the front. The first winding portion 511 and the second winding portion 512 may be connected to each other by a connecting portion 513.

[0075] The curved side 63 of the shell 150 may include a 1-1 quarter circle side 311 and a 1-2 quarter circle side 312 respectively accommodating or facing two corners of the first winding portion 511 and a 2-1 quarter circle side 321 and a 2-2 quarter circle side 322 respectively accommodating or facing two corners of the second winding portion 512.

[0076] A quarter circle side refers to a quarter of a three-dimensional structure in which the four corners of a quadrilateral are formed into curved lines or arc lines when viewed from a plan view and have a quadrilateral when viewed from the front. A quarter circle forming a curve refers to a segment when a circle is divided into four equal parts by orthogonal diameters. The length of one segment of the arc is equivalent to a quarter of the circumference.

[0077] The electrolyte holding space ES2 can be defined by the first side S21 of the first winding portion 511 and the second side S22 of the second winding portion 512 (formed by a racetrack-shaped column) and the flat sides 1511 and 1512 facing the first side S22 and the second side S22, or between them, thereby increasing the injection or holding capacity of the electrolyte.

[0078] The case 150 may include 1-1 flat side 1511 and 1-2 flat side 1512 and 2-1 flat side 1521 and 2-2 flat side 1522. The first winding portion 511 and the second winding portion 512 may be wound in the same direction, and an electrolyte accommodation space ES2 having a symmetrical structure or having a symmetrical structure may be formed or provided between the 1-1 flat side 1511 and the 1-2 flat side 1512. The symmetrical electrolyte accommodation space ES2 may help to make the amount of electrolyte impregnated on the electrode assembly 50 uniform.

[0079] Figure 8 is a side view showing a winding direction of a stacked body forming an electrode assembly of a rechargeable battery according to a third embodiment of the present disclosure. Fig. 9 yes Figure 8 A cross-sectional view of the electrode assembly in the housing. Figure 8 and Fig. 9 The electrode assembly 70 of the rechargeable battery 3 of the third embodiment may further include a third winding portion 713 (eg, a cylinder) between the first winding portion 111 and the second winding portion 112 .

[0080] The connection part 73 may include a 1-3 connection part 731 connecting the first winding part 111 and the third winding part 713 and a 3-2 connection part 732 connecting the third winding part 713 and the second winding part 112. The third winding part 713 may be wound with a pair of mandrels 85 on the upper and lower surfaces of the middle position of the stack 11.

[0081] The curved side 83 of the shell 80 may include a first arc side 831 accommodating or facing one side (eg, arc side) of the first winding portion 111 and a second arc side 832 accommodating or facing one side (eg, arc side) of the second winding portion 112 .

[0082] The arc side refers to a portion of a three-dimensional structure having an oval shape with opposite sides formed by curves and the two curves connected by a straight line when viewed from a plane, and having a quadrilateral shape when viewed from the front. The arc side forming the curve refers to a segment when a circle, oval or ellipse is divided into two parts by its diameter or major axis. In one embodiment, the length of the arc in one segment may be equal to 1 / 2 of the circumference.

[0083] The electrolyte holding space ES3 can be set by the first side S31 of the first winding portion 111, the third side S33 of the third winding portion 713, the fourth side S34 of the third winding portion 713, the second side S32 of the second winding portion 112, and the flat sides 81 and 82 facing the first side S31 and the third side S33 and facing the fourth side S34 and the second side S32, or between them, so as to increase the injection amount of the electrolyte.

[0084] The first winding portion 111 and the second winding portion 112 may be wound in opposite directions, and the third winding portion 713 may be formed by winding the stacked body 11 in two layers and may be wound in the same direction as the first winding portion 11. The third winding portion 713 may be formed by winding the stacked body 11 in two layers in one turn, and thus the number of turns may be less than the number of turns of each of the first winding portion 111 and the second winding portion 112.

[0085] The first winding portion 111 , the second winding portion 112 , and the third winding portion 713 of the third embodiment may form a relatively large number of electrolyte accommodation spaces ES3 in the case 80 , and thus the injection amount of the electrolyte may be further increased.

[0086] Fig.10 is a cross-sectional view of a state in which an electrode assembly in a rechargeable battery according to a fourth embodiment of the present disclosure is in a case. Fig.10 The electrode assembly 90 of the rechargeable battery 4 of the fourth embodiment may further include a third wound portion 913 formed as a racetrack-shaped column between the first wound portion 511 and the second wound portion 512 .

[0087] The curved side 63 of the housing 100 may include 1-1 quarter circle sides 311 and 1-2 quarter circle sides 312 respectively accommodating or facing two corners of the first winding portion 511 and 2-1 quarter circle sides 321 and 2-2 quarter circle sides 322 respectively accommodating or facing two corners of the second winding portion 512.

[0088] The electrolyte holding space ES4 can be set by the first side S21 of the first winding portion 511 (which can be formed by a runway-shaped column), the third side S23 of the third winding portion 913, the fourth side S24 of the third winding portion 913 and the second side S22 of the second winding portion 512, and the flat sides 1011, 1012 facing the first side S21 and the third side S23 and facing the fourth side S24 and the second side S22, or between them, thereby increasing the injection amount of the electrolyte.

[0089] The case 100 may include 1-1 flat side 1011 and 1-2 flat side 1012 and 2-1 flat side 1021 and 2-2 flat side 1022. The first winding portion 511 and the second winding portion 512 may be wound in opposite directions, and an electrolyte accommodation space ES4 having a symmetrical structure may be formed between the 1-1 flat side 1011 and the 1-2 flat side 1012. The symmetrical electrolyte accommodation space ES4 may help to make the amount of injected electrolyte impregnated on the electrode assembly 90 uniform.

[0090] The first winding portion 511 and the second winding portion 512 may be wound in the same direction, and the third winding portion 913 may be formed by winding the stacked body 11 in two layers, and may be wound in the same direction as the first winding portion 511. The third winding portion 913 may be formed by winding the stacked body 11 in two layers in one turn, and thus the number of turns may be less than the number of turns of each of the first winding portion 511 and the second winding portion 512.

[0091] The first winding portion 511 , the second winding portion 512 , and the third winding portion 913 of the fourth embodiment can form a relatively large number of electrolyte accommodation spaces ES4 in the housing 150 , so the injection amount of the electrolyte can be further increased.

[0092] As a summary and review, cylindrical rechargeable batteries may generate excess space due to their circular structure, and the electrode assembly may occupy more than 97% of the space due to the internal structure of the case, making it difficult to secure or accommodate sufficient electrolyte.

[0093] One or more embodiments may provide a rechargeable battery in which an injection amount of an electrolyte is increased.

[0094] One or more embodiments may provide a rechargeable battery that increases the injection amount of an electrolyte while reducing the overall space of a case accommodating an electrode assembly.

[0095] In a cylindrical rechargeable battery according to one embodiment, the structure of the shell may include curved surfaces on both sides to accommodate an electrode assembly having a plurality of winding parts, and the middle portion may be a flat surface connected to the curved surfaces to accommodate the electrode assembly, so that the electrolyte accommodating space may be between the plurality of winding parts and the flat surface.

[0096] In this way, the electrolyte accommodation space can be increased while reducing the overall space inside the case, thereby increasing the injection amount of the electrolyte. This releases the capacity of the rechargeable battery.

[0097] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and interpreted in a general and descriptive sense only and not for limiting purposes. In some cases, as will be apparent to one of ordinary skill in the art at the time of filing this application, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise specifically indicated. Accordingly, those skilled in the art will appreciate that various changes in form and detail may be made without departing from the scope of the invention as set forth in the claims.

Claims

1. A rechargeable battery comprising: an electrode assembly including a first winding portion and a second winding portion connected by a connecting portion, the first winding portion and the second winding portion being formed by winding at each of both ends of a stack of a first electrode plate, a first separator, a second electrode plate, and a second separator; as well as a housing accommodating the electrode assembly, in: The housing comprises: flat sides facing each other at both sides of the housing in the width direction; and curved sides at both ends of the housing in the length direction, and The flat side and the first and second wound portions surround an electrolyte accommodation space between the flat side and the first and second wound portions. 2 . The rechargeable battery according to claim 1 , wherein the connection part is a portion of the stack of the first electrode plate, the first separator, the second electrode plate, and the second separator.

3. The rechargeable battery according to claim 1, wherein: The first winding portion and the second winding portion have a cylindrical shape, and The curved side of the housing includes a first arc side and a second arc side, the first arc side faces one side of the first winding portion, and the second arc side faces one side of the second winding portion.

4. The rechargeable battery according to claim 1, wherein the electrolyte accommodation space is surrounded by the first side of the first winding portion and the second side of the second winding portion and the flat side, Each of the first winding portion and the second winding portion has a cylindrical shape, The flat side faces the first side of the first winding portion and the second side of the second winding portion.

5. The rechargeable battery according to claim 4, wherein: The first winding portion and the second winding portion are wound in the same direction, and The electrolyte accommodation space has a symmetrical structure between the flat sides of the case.

6. The rechargeable battery according to claim 1, wherein: The first winding portion and the second winding portion have a racetrack column shape, and The curved side of the housing comprises: The 1-1 quarter circle side and the 1-2 quarter circle side respectively face two corners of the first winding portion; and The quarter-circle side 2-1 and the quarter-circle side 2-2 face two corners of the second winding portion respectively.

7. The rechargeable battery according to claim 1, wherein the electrolyte accommodation space is surrounded by a first side of the first winding portion and a second side of the second winding portion and the flat side, Each of the first winding portion and the second winding portion has a racetrack column shape, The flat side faces the first side of the first winding portion and the second side of the second winding portion.

8. The rechargeable battery according to claim 7, wherein: The flat side includes a 1-1 flat side and a 1-2 flat side, The housing further includes a 2-1 flat side and a 2-2 flat side at the two ends of the housing in the length direction, The first winding portion and the second winding portion are wound in the same direction, and The electrolyte containing space has a symmetrical structure between the 1-1 flat side and the 1-2 flat side.

9. The rechargeable battery according to claim 1, wherein: The electrode assembly further includes a third wound portion between the first wound portion and the second wound portion, each of the first wound portion, the second wound portion, and the third wound portion having a cylindrical shape, The connecting portion comprises: 3-1 a connecting portion, connecting the first winding portion and the third winding portion; and 3-2 a connecting portion connecting the third winding portion and the second winding portion, and The curved side of the housing includes a first arc side and a second arc side, the first arc side faces one side of the first winding portion, and the second arc side faces one side of the second winding portion.

10. The rechargeable battery according to claim 9, wherein the electrolyte accommodation space is surrounded by a first side of the first wound portion opposite to the one side of the first wound portion, a third side of the third wound portion, a fourth side of the third wound portion, a second side of the second wound portion opposite to the one side of the second wound portion, and the flat side, The flat side faces the first side of the first winding portion, the third side of the third winding portion, the fourth side of the third winding portion, and the second side of the second winding portion.

11. The rechargeable battery according to claim 10, wherein: The first winding portion and the second winding portion are wound in opposite directions, and The third winding portion is formed by winding the stacked body in two layers, and is wound in the same direction as the first winding portion.

12. The rechargeable battery according to claim 1, wherein: The electrode assembly further includes a third winding portion between the first winding portion and the second winding portion, the first winding portion, the third winding portion, and the second winding portion each having a racetrack column shape, and The curved side of the housing comprises: The 1-1 quarter circle side and the 1-2 quarter circle side respectively face two corners of the first winding portion; and The quarter-circle side 2-1 and the quarter-circle side 2-2 face two corners of the second winding portion respectively.

13. The rechargeable battery according to claim 12, wherein the electrolyte accommodation space is surrounded by the first side of the first winding portion, the third side of the third winding portion, the fourth side of the third winding portion, the second side of the second winding portion, and the flat side, The flat side faces the first side of the first winding portion, the third side of the third winding portion, the fourth side of the third winding portion, and the second side of the second winding portion.

14. The rechargeable battery according to claim 13, wherein: The flat side includes a 1-1 flat side and a 1-2 flat side, The housing further includes a 2-1 flat side and a 2-2 flat side at the two ends of the housing in the length direction, The first winding portion and the second winding portion are wound in opposite directions, and The third winding portion is formed by winding the stacked body in two layers, and is wound in the same direction as the first winding portion.

15. The rechargeable battery according to claim 1, further comprising: a cover plate, closing and sealing the opening of the housing; as well as an electrode terminal connected to the second uncoated region of the second electrode plate and mounted in an insulating structure on the cap plate, and The housing is connected to the first uncoated region of the first electrode plate.

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