Electrode assembly and battery cell comprising same

Abstract

The present disclosure relates to an electrode assembly and a battery cell comprising the same, the electrode assembly comprising: a first electrode comprising a first electrode plate on which an active material is laminated and a plurality of first flag portions respectively extending from the first electrode plate; a second electrode including a second electrode plate on which another active material is laminated; and a separator provided between the first electrode and the second electrode, the first electrode, the separator, and the second electrode being wound around a virtual central axis, the plurality of first flag portions extending parallel to the central axis, and the second flag portions extending parallel to the central axis. The angle between any one of the plurality of first flag portions and another first flag portion adjacent to the any one first flag portion increases toward the central axis in the winding direction of the first electrode, i.e., the spiral direction.

Description

Technical Field

[0001] This disclosure relates to an electrode assembly and a battery cell including the electrode assembly. More specifically, it relates to an electrode assembly that reduces the weight of the battery cell and a battery cell including the electrode assembly. Background Technology

[0002] A typical cylindrical battery cell (or secondary battery) consists of an electrode assembly (or jelly roll) that is formed by stacking a positive electrode, a separator, and a negative electrode in sequence and winding them around a central axis. In this case, the electrode assembly is connected to the positive and negative current collectors by bending multiple flags formed on the positive and negative electrodes, respectively.

[0003] Typically, multiple flags are formed by cutting portions from both the positive and negative electrodes along a direction parallel to the central axis. These cut flags are then bent towards the central axis, allowing them to overlap. However, the overlap of these flags increases unnecessarily as the winding length of the electrode assembly grows, resulting in a thicker overlap. This ultimately increases the weight of the electrode assembly unnecessarily and reduces the energy density per unit mass. Furthermore, the thickened overlap may make it difficult to stably maintain the bending shape of the flags. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] According to one aspect of this disclosure, the technical problem to be solved is to improve the manufacturing efficiency of electrode assemblies and / or battery cells.

[0006] According to another aspect of this disclosure, the technical problem to be solved is to reduce the weight of electrode assemblies and / or cells.

[0007] According to another aspect of this disclosure, the technical problem to be solved is to increase the energy density per unit mass of electrode assemblies and / or cells.

[0008] According to another aspect of this disclosure, the technical problem to be solved is to stably maintain the bending shape of multiple flag sections.

[0009] According to another aspect of this disclosure, the technical problem to be solved is to provide an electrode assembly that applies a relational relationship between the angle between adjacent flags and other physical variables.

[0010] On the other hand, the electrode assembly and battery cell including the electrode assembly according to this disclosure can be widely used in electric vehicles, battery charging stations, energy storage systems (ESS), and other green technologies such as solar power generation and wind power generation that utilize batteries. Furthermore, the electrode assembly and battery cell including the electrode assembly according to this disclosure can be used in eco-friendly mobility vehicles, including electric vehicles and hybrid vehicles, to prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0011] (II) Technical Solution

[0012] The electrode assembly according to this disclosure may include: a first electrode including a plurality of first flags extending from a first electrode plate having an active material laminated thereon; a second electrode including a second electrode plate having another active material laminated thereon; and a diaphragm disposed between the first electrode and the second electrode, wherein the first electrode, the diaphragm, and the second electrode are wound around a virtual central axis, the plurality of first flags extending parallel to the central axis, and the angle between any one of the plurality of first flags and another first flag adjacent to the first flag increases as it approaches the central axis along the winding direction of the first electrode, i.e., the helical direction.

[0013] In one embodiment, the second electrode may further include: a plurality of second flags extending from the second electrode plate in a direction opposite to the direction in which the plurality of first flags extend, and bent toward the central axis.

[0014] In one embodiment, the first electrode plate may include: a first region on which an active material is stacked and faces the diaphragm; and a second region formed between the plurality of first flags and the first region, wherein the first electrode plate is exposed and faces the diaphragm.

[0015] In one embodiment, the height h1 of the second region in the first portion adjacent to the central axis may be less than the height h2 of the second region in the second portion that is further away from the central axis than the first portion.

[0016] In one embodiment, each of the plurality of first flag portions may include: a first edge portion extending obliquely relative to the central axis; a second edge portion extending parallel to the central axis; a third edge portion connecting to the first edge portion and the second edge portion along the helical direction; and a connecting edge portion connecting the plurality of first flag portions and the second region.

[0017] In one embodiment, the angle may be the angle between the second edge of any first flag portion and the first edge of a first flag portion adjacent to any first flag portion.

[0018] In one embodiment, the lengths of the connecting edges of the plurality of first flags may be the same.

[0019] In one embodiment, the first edge portion may be closer to the central axis along the spiral direction than the second edge portion.

[0020] In one embodiment, the heights of the plurality of first flag sections may be the same as each other.

[0021] In one embodiment, the angle θ between any first flag section and the first flag section adjacent to the any first flag section can be set according to the following relationship 1.

[0022] [Relation 1]

[0023] ,

[0024] In the relation 1, L n R represents the length from one end of the first electrode plate closest to the central axis to the nth first flag section. o d represents the radius of the end of the first electrode plate wound around the central axis that is closer to the central axis. n The length of the connection between the nth set first flag and the first electrode plate is represented by t, and the sum of the thicknesses of the first electrode, the second electrode and the diaphragm is represented by t, where n is a natural number.

[0025] In one embodiment, the angle θ between any one of the first flag portions and the first flag portion adjacent to the any one of the first flag portions can be determined based on the length L from one end of the first electrode plate closest to the central axis to the nth set first flag portion. n The change is where n is a natural number.

[0026] On the other hand, the electrode assembly according to this disclosure may include: a first electrode including a plurality of first flags extending from a first electrode plate having an active material laminated thereon; a second electrode including a second electrode plate having another active material laminated thereon; and a diaphragm disposed between the first electrode and the second electrode, wherein the first electrode, the diaphragm, and the second electrode are wound around a virtual central axis, the plurality of first flags extending parallel to the central axis and along the winding direction of the first electrode, i.e., the helical direction, wherein the angle between a pair of adjacent first flags in the first portion adjacent to the central axis is greater than the angle between a pair of adjacent first flags in the second portion further away from the central axis than the first portion.

[0027] In one embodiment, from the second portion to the first portion, the angle between a pair of adjacent first flags among the plurality of first flag portions can be increased.

[0028] In one embodiment, the plurality of first flag parts can be divided into a plurality of first flag part groups, which are formed by grouping adjacent first flag parts into a predetermined number. The angle between a pair of first flag parts in the same first flag part group can be the same, and the angle between a pair of first flag parts in any first flag part group can be larger the closer it is to the central axis.

[0029] On the other hand, an electrode assembly according to this disclosure may include: a first electrode including a plurality of first flags extending from a first electrode plate having an active material laminated thereon; a second electrode including a second electrode plate having another active material laminated thereon; and a diaphragm disposed between the first electrode and the second electrode, wherein the first electrode, the diaphragm, and the second electrode are wound around a virtual central axis, each of the plurality of first flags including: a first edge extending obliquely relative to the central axis; and a second edge extending parallel to the central axis, each of the plurality of first flags being bent such that the first edge and the second edge face the central axis, such that the angle formed by the first edge and the second edge around the central axis increases as it approaches the central axis along the winding direction of the first electrode, i.e., the helical direction.

[0030] In one embodiment, the electrode assembly according to this disclosure may further include: a first current collector electrically connected to the plurality of first flag portions and terminal portions.

[0031] In one embodiment, the plurality of first flags and the first current collector can be joined together by welding.

[0032] In one embodiment, the electrode assembly according to this disclosure may further include: a second current collector located on the opposite side of the first current collector and electrically connected to the second electrode, wherein the first electrode, the second electrode and the diaphragm are sandwiched between the first current collector and the second current collector.

[0033] In one embodiment, the second electrode may further include: a plurality of second flags extending from the second electrode plate in a direction opposite to the extending direction of the plurality of first flags, the plurality of second flags being bent toward the central axis and electrically connected to the second current collector.

[0034] In one embodiment, any one of the plurality of first flag sections and another first flag section adjacent to the stated first flag section can be bent to form a coplanarity.

[0035] On the other hand, the battery cell according to this disclosure may include: a housing for accommodating the electrode assembly; a through hole extending through one side of the housing along the central axis; and a terminal portion inserted into the through hole to electrically connect the electrode assembly to the outside.

[0036] (III) Beneficial Effects

[0037] According to one embodiment of this disclosure, the manufacturing efficiency of electrode assemblies and / or battery cells can be improved.

[0038] According to another embodiment of this disclosure, the weight of the electrode assembly and / or the battery cell can be reduced.

[0039] According to another embodiment of this disclosure, the energy density per unit mass of the electrode assembly and / or the battery cell can be increased.

[0040] According to another embodiment of this disclosure, the bending shape of multiple flag sections can be stably maintained.

[0041] According to another embodiment of this disclosure, an electrode assembly can be provided that applies a relational relationship between the angles between adjacent flags and other physical variables. Attached Figure Description

[0042] Figure 1 This is an example of a battery cell according to this disclosure.

[0043] Figure 2 A cross-section of a battery cell according to this disclosure is shown.

[0044] Figure 3 This is an example of an electrode assembly according to this disclosure prior to bending the first and second flag sections.

[0045] Figure 4The outline of the electrode assembly according to this disclosure is shown as viewed from one direction.

[0046] Figure 5a This is an enlarged view of the first part of the first electrode adjacent to the central axis.

[0047] Figure 5b This is an enlarged view of the second part of the first electrode, which is positioned further away from the central axis than the first part.

[0048] Figure 6a The first flag section, which bends toward the central axis, is shown in the first part.

[0049] Figure 6b The first flag section, which bends toward the central axis, is shown in the second part.

[0050] Figure 7 This is another example of the first electrode according to this disclosure.

[0051] Explanation of reference numerals in the attached figures:

[0052] 100: Battery cell; 20: Electrode assembly

[0053] 21: First electrode; 22: Second electrode

[0054] 25: Diaphragm 210: First Flag Section

[0055] 211, 221: Active material; 215: First electrode plate

[0056] 220: Second Flag Section; 225: Second Electrode Plate Detailed Implementation

[0057] The preferred embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The configurations or control methods of the apparatus described below are merely illustrative of embodiments of the present disclosure and are not intended to limit the scope of the present disclosure, and the same reference numerals used throughout the specification denote the same components.

[0058] In this disclosure, battery, secondary battery or cell are used as terms having the same meaning as cell.

[0059] Figure 1 This is an example of a battery cell according to this disclosure.

[0060] Reference Figure 1 The battery cell 100 manufactured according to the battery manufacturing apparatus of this disclosure may include: housings 110, 120, and internally housing electrode assemblies 20 for producing or storing electrical energy (see reference). Figure 2 ); and terminal portion 130, which is electrically connected to the electrode assembly 20 and protrudes outward.

[0061] The housings 110 and 120 can form the shape of the battery cell 100. Although Figure 1 An example of a cylindrical housing 110, 120 is shown, but the shape of the battery cell is not limited to this in this disclosure. That is, the battery cell 100 according to this disclosure can be a prismatic or pouch-shaped battery cell 100, or a battery cell 100 of other shapes.

[0062] The housings 110 and 120 may include: an outer shell 110, one end of which includes a facing direction located at the terminal portion 130 (refer to...). Figure 1 The opening 115 on the ) (refer to) Figure 2 The opening 115 accommodates the electrode assembly 20, and the cover assembly 120 is attached to the housing 110 to close the opening 115.

[0063] That is, the outer shell 110 can be formed from a circular disc into a cup shape using a deep drawing method. Therefore, the opening 115 is formed on one side of the outer shell 110, and the other side of the outer shell 110 facing the opening 115 can be closed.

[0064] The outer casing 110 may include a side surface 113 forming a circumferential surface and a flat surface 111 forming the other end of the outer casing 110.

[0065] The terminal portion 130 may be located on one side (or the flat portion 111) of the housing 110 facing the opening 115 or the cover assembly 120. The battery cell 100 may further include a through hole (not shown) penetrating the flat portion 111, and at least a portion of the terminal portion 130 may be inserted into the through hole.

[0066] According to this disclosure, the battery cell 100 may further include a gasket 135 located between the terminal portion 130 and the through hole to electrically insulate the terminal portion 130 from the housings 110 and 120.

[0067] In one embodiment, the washer 135 may be disposed between the housing 110 and the terminal portion 130. For example, the washer 135 may be disposed between the flat portion 111 and the terminal portion 130. The washer 135 may comprise an electrically insulating material. An insulating material refers to a material with low conductivity. As an example, the insulating material may be any one of polymers, ceramics, or a combination thereof.

[0068] Figure 2 A cross-section of a battery cell according to this disclosure is shown.

[0069] More specifically, Figure 2 A cross-section is shown of the area adjacent to the cover assembly 120 covering the opening 115 and the area adjacent to the other side of the housing 110 or the flat portion 111.

[0070] The battery cell 100 may internally house the electrode assembly 20. The electrode assembly 20 may be in a form corresponding to the cylindrical shape of the outer casing 110 or the side portion 113.

[0071] That is, the electrode assembly 20 may be the first electrode 21 (refer to...) Figure 3 ), second electrode 22 (refer to) Figure 3 ) and the diaphragm 25 located between the first electrode 21 and the second electrode 22 (see reference) Figure 3 A roll shape that is wound around the central axis A.

[0072] Therefore, the housing 110 and the electrode assembly 20 can share the central axis A.

[0073] Additionally, the electrode assembly 20 may include a central hole 160h in a region adjacent to the central axis A. The closer to the central axis A, the greater the degree of bending (e.g., radius of curvature) of the electrode assembly 20, thus the central hole 160h can be used to prevent damage to the electrode assembly 20.

[0074] Additionally, the central hole 160h can serve as a channel for injecting electrolyte. That is, the electrolyte can be injected through the central hole 160h to impregnate the electrode assembly 20.

[0075] In this disclosure, the first electrode 21 may represent either the positive electrode or the negative electrode, and the second electrode 22 may represent the other electrode.

[0076] The battery cell 100 may include a current collector 140 electrically connecting the terminal portion 130 and the electrode assembly 20. The current collector 140 may include a first current collector 141 electrically connecting the first electrode 21 and the terminal portion 130, and a second current collector 142 electrically connecting the second electrode 22 and the housing 110, 120, or the side portion 113. In contrast, the second current collector 142 may also be electrically connected to the cover assembly 120 and the electrode assembly 20.

[0077] In addition, for electrical insulation between the housings 110, 120 and the first current collector 141, the battery cell 100 may further include an insulating cover 119 between the planar portion 111 and the first current collector 141.

[0078] Additionally, the battery cell 100 may further include an insulating component 125 for electrically insulating the cover assembly 120 and the housing 110.

[0079] The cover assembly 120 may be disc-shaped with the central axis A as its center. Additionally, the cover assembly 120 may include an injection hole 128 extending through the cover assembly 120 along the central axis A.

[0080] The injection port 128 can be used when injecting electrolyte into the interior of the housing 110. The battery cell 100 may further include a spherical closure portion 129 that closes the injection port 128 after the electrolyte is injected.

[0081] The electrolyte EL can be injected through the injection hole 128 after the cover assembly 120 is attached to the housing 110 and before the injection hole 128 is closed.

[0082] However, unlike this, the electrolyte EL can also be injected into the interior of the housing 110 through the opening 115 before the cap assembly 120 is attached.

[0083] That is, the electrolyte EL can be injected before or after the cap assembly 120 is joined. Whether the electrolyte EL is injected through the opening 115 or through the injection hole 128, the electrolyte EL can ultimately be injected through the central hole 160h.

[0084] Figure 3 This is an example of an electrode assembly according to this disclosure prior to bending the first and second flag sections.

[0085] The electrode assembly 20 according to this disclosure may include a first electrode 21, a second electrode 22, and a diaphragm 25 disposed between the first electrode 21 and the second electrode 22.

[0086] The first electrode 21 can have either a positive or a negative polarity, and the second electrode 22 can have the other polarity. The diaphragm 25 can be used to electrically separate the first electrode 21 and the second electrode 22. Alternatively, the diaphragm 25 can also wrap around the outermost edge of the wound electrode assembly 20, thereby electrically separating the electrode assembly 20 from the housing 110.

[0087] For ease of explanation, this disclosure defines any one of the electrode assembly 20, the first electrode 21, and the second electrode 22 around the central axis A (or the central hole 160h (see reference)). Figure 2 When wound into a coil shape with the reference axis A (or center hole 160h (refer to)), the coil should be oriented towards the central axis A (or center hole 160h (refer to)). Figure 2The direction of winding is called the helical direction DR. In this specification, the helical direction DR may also refer to the opposite direction (or unwinding direction) away from the central axis A.

[0088] Furthermore, for ease of explanation, this disclosure uses a virtual central axis A as a reference, designating the direction parallel to the central axis as the first direction, and the radial direction based on the central axis as the second direction. As an example, the first direction and the second direction can respectively represent the height direction and the radial direction of a cylindrical coordinate system.

[0089] Specifically, the first electrode 21 may include: a first electrode plate 215, on which an active material 211 is stacked; and a plurality of first flags 210, which extend from the first electrode plate 215 along a first direction parallel to the central axis A and are arranged along the spiral direction DR.

[0090] On the other hand, the second electrode 22 may further include a plurality of second flag portions 220, which extend from the second electrode plate 225 in a direction opposite to the extending direction of the plurality of first flag portions 210.

[0091] In addition, the plurality of second flag portions 220 may extend from the second electrode plate 225 in a direction opposite to the direction in which the plurality of first flag portions 210 extend, and bend toward the central axis.

[0092] More specifically, the second electrode 22 may include: another active material 221 stacked on the second electrode plate 225; and a plurality of second flags 220 extending from the second electrode plate 225 in a direction opposite to the extending direction of the plurality of first flags 210.

[0093] The plurality of first flag sections 210 and the plurality of second flag sections 220 may be symmetrical to each other.

[0094] As an example, the plurality of first flag portions 210 can be configured in a trapezoidal shape, and the portion corresponding to any hypotenuse of the trapezoidal shape can be parallel to the first direction. That is, the portion corresponding to any hypotenuse of the trapezoidal shape can be perpendicular to the second direction and the spiral direction. The portion corresponding to any hypotenuse of the trapezoidal shape can be configured to be inclined to the first direction.

[0095] Furthermore, in each of the plurality of first flag portions 210, the inclined side of the trapezoidal shape may be closer to the central axis A along the spiral direction DR than the inclined side parallel to the first direction.

[0096] The plurality of second flag sections 220 may also have the same shape as the plurality of first flag sections 210.

[0097] The plurality of first flag portions 210 can minimize the area of ​​overlap when bent by using a trapezoidal shape. Similarly, the plurality of second flag portions 220 can also minimize the area of ​​overlap when bent.

[0098] Furthermore, the plurality of first flag sections 210 and the plurality of second flag sections 220 may protrude in different directions. This is to prevent short circuits between the plurality of first flag sections 210 and the plurality of second flag sections 220.

[0099] Additionally, the first electrode plate 215 may include: a first region 215a (refer to...) Figure 5a An active substance 211 is stacked on the first region; and a second region 215b (see reference) Figure 5b ), formed between the plurality of first flag sections 210 and the first region 215a.

[0100] The second region 215b may be an exposed region (barre region) where the first electrode plate 215 of the metal material is directly exposed to air or electrolyte without being coated with the active material 211.

[0101] The first region 215a may be the area of ​​the first electrode plate 215 that is covered or covered by the active material 211.

[0102] That is, in the first region 215a, the active material may face the membrane 25, while in the second region 215b, the first electrode plate 215 may face the membrane 25.

[0103] When the first flag portion 210 bends toward the central axis A, the second region 215b can prevent the active material 211 from separating from the first electrode plate 215 and can facilitate the folding of the first flag portion 210.

[0104] That is, the first electrode 21 can be wound into a coil shape along the spiral direction DR. The second electrode 22 and the diaphragm 25 are also wound in the same way.

[0105] That is, the first electrode 21, the second electrode 22 and the diaphragm 25 can be rolled into a roll shape along the spiral direction DR after being stacked.

[0106] On the other hand, unless otherwise specified, the descriptions of the first region 215a and the second region 215b can also be applied to the second electrode 22.

[0107] Reference Figure 2 and Figure 3 The electrode assembly 20 according to this disclosure may further include a first current collector 141 electrically connected to the plurality of first flags 210.

[0108] In the plurality of first flag sections 210, the bent plurality of first flag sections 210 and the first current collector 141 can be electrically connected.

[0109] Therefore, the battery cell 100 according to this disclosure may further include a first current collector 140 electrically connecting the plurality of first flag portions 210 and the terminal portions 130.

[0110] The first current collector 141 and the plurality of first flags 210 can be connected by welding. The welding method for connecting the first current collector 141 and the plurality of first flags 210 can be ultrasonic welding or laser welding.

[0111] Additionally, refer to Figure 2 and Figure 3 The electrode assembly 20 according to this disclosure may further include a second current collector 142, which is located on the opposite side of the first current collector 141 and electrically connected to the second electrode 22. The first electrode 21, the second electrode 22 and the diaphragm 25 are sandwiched between the first current collector 141 and the second current collector 142.

[0112] Additionally, the second electrode 22 may further include a plurality of second flags 220 extending from the second current collector 225 in a direction opposite to the extending direction of the plurality of first flags 210, and the plurality of second flags 220 may be bent toward the central axis A to be electrically connected to the second current collector 142.

[0113] Similarly, the cell 100 according to this disclosure may further include a second current collector 142, which is located on the opposite side of the first current collector 141 and electrically connected to the second electrode 22 and the housings 110 and 120, wherein the first electrode 21, the second electrode 22 and the diaphragm 25 are sandwiched between the first current collector 141 and the second current collector 142.

[0114] Additionally, the electrode assembly 20 may include a diaphragm 25 stacked between the first electrode 21 and the second electrode 22. For this purpose, the diaphragm 25 may be formed of an insulating material.

[0115] Figure 3 An example is shown where the first electrode 21, the second electrode 22, and the diaphragm 25 are each formed from a sheet and stacked, then rolled up like a scroll. However, instead of this, the first electrode 21, the second electrode 22, and the diaphragm 25 can also be stacked (or layered) multiple times in sequence and then bent according to the shape of the housing 110.

[0116] Figure 4 The outline of the electrode assembly according to this disclosure is shown as viewed from one direction.

[0117] Figure 4 An example of the electrode assembly 20 being wound into a circle with the central axis A as a reference is shown. Therefore, the first electrode 21 can also be wound into a circle with the central axis A as a reference.

[0118] As described above, in the first electrode 21, the plurality of first flag portions 210 can be bent toward the central axis A. Similarly, in the second electrode 22, the plurality of second flag portions 220 can be bent toward the central axis A.

[0119] When the plurality of first flag sections 210 are bent, adjacent first flag sections 210 may overlap. In order to remove unnecessary overlap or prevent the unnecessary overlap from increasing, it is necessary to change the angle between the adjacent first flag sections 210.

[0120] In order to set different angles between the adjacent first flag portions 210, assuming that the first electrode plate 215 is in the shape of an unfolded sheet before winding, the following mathematical formula 1 can be valid.

[0121] [Mathematical Expression 1]

[0122]

[0123] In the mathematical formula 1, L n (n is a natural number) can represent the length from one end of the first electrode plate 215 closest to the central axis A to the nth set first flag portion 210 (refer to...). Figure 7 ), R n R can represent the radius from the central axis A to the nth first flag portion 210 in the wound state. oThe radius can be represented by the radius of the end of the first electrode plate 215 wound with the central axis A as a reference in the wound state, t can be represented by the sum of the thicknesses of the first electrode 21, the second electrode 22 and the diaphragm 25, and θ can be represented by the angle between any one of the first flag portions 210 and another first flag portion 210 adjacent to the first flag portion 210 or the angle between a pair of adjacent first flag portions 210.

[0124] For reference, L n It can be the distance from one end of the first electrode plate 215 adjacent to the central axis A to the nth first flag portion 210. Therefore, R n It can be the radius of the first flag section 210 of the nth setting.

[0125] More specifically, L n It can be the length d of the first flag section 210, including the nth setting. n The length.

[0126] Here, any one of the first flag sections 210 can be the nth set first flag section 210, and the first flag section 210 adjacent to any one of the first flag sections 210 can be the (n-1)th set first flag section 210 (except when n is 1).

[0127] Furthermore, more specifically, θ is the angle between any one of the first flag portions 210 and another first flag portion 210 adjacent to the first flag portion 210, or the angle between a pair of adjacent first flag portions 210, and the angle formed by the first edge portion 216 and the second edge portion 217 of the first flag portion 210 having an angular relationship with the central axis A is the same, so the following mathematical formula 2 can be valid.

[0128] [Mathematical Expression 2]

[0129]

[0130] In the mathematical formula 2, R n The radius d can be represented by the radius from the central axis A to the nth first flag section 210. n This can refer to the connection length between the nth first flag portion 210 and the first electrode plate 215 (or, the length of the portion where the nth first flag portion 210 connects to the first electrode plate 215 or the connection edge portion 213 (refer to...) Figure 5aθ can represent the angle between the first flag part 210 of the nth arrangement and another first flag part 210 adjacent to the first flag part 210 of the nth arrangement, or the angle between a pair of first flag parts 210 that are adjacent to each other.

[0131] The angle between any one of the first flag sections 210 and another first flag section 210 adjacent to the first flag section 210, or the angle between a pair of adjacent first flag sections 210, can be set according to the following relation 1 derived from the mathematical formula 1 and the mathematical formula 2.

[0132] [Relation 1]

[0133]

[0134] In the relation 1, L n (n is a natural number) can represent the length from one end of the first electrode plate 215 closest to the central axis A to the nth set first flag portion 210 (refer to...). Figure 7 ), R o The radius d can be expressed as the radius of the end of the first electrode plate 215 wound around the central axis A that is closer to the central axis. n The connection length between the nth first flag section 210 and the first electrode plate 215 can be represented by t, which can represent the sum of the thicknesses of the first electrode 21, the second electrode 22 and the diaphragm 25, and θ can represent the angle between any one of the first flag sections 210 and another first flag section 210 adjacent to the first flag section 210, or the angle between a pair of adjacent first flag sections 210.

[0135] If expressed in a different way, then d n It can be the connecting edge 213 of the nth set first flag portion 210 (refer to) Figure 5a The length of ).

[0136] On the other hand, if the d of the nth set first flag part 210 n As d, having the same value as the other first flags 210, the relation 1 can also be transformed into the following relation 2.

[0137] [Relationship 2]

[0138]

[0139] Referring to either relation 1 or relation 2, the angle between any first flag portion 210 and another first flag portion 210 adjacent to the first flag portion 210 can gradually increase as the first flag portion 210 and the other first flag portion 210 move closer to the central axis A along the spiral direction DR.

[0140] Alternatively, the angle can be the angle between the second edge portion 217 of any one of the first flag portions 210 and the first edge portion 216 of the first flag portion 210 adjacent to any one of the first flag portions.

[0141] As an example, the angle can be the angle of the plurality of first flag portions 210 before bending. Therefore, the angle between the second edge portion 217 of any first flag portion 210 and the first edge portion 216 of the first flag portion 210 adjacent to the first flag portion 210 before bending can gradually increase as the first flag portion 210 and the first flag portion 210 adjacent to the first flag portion move closer to the central axis A.

[0142] The winding length L of the first electrode plate 215 can vary depending on the size of the battery cell 100. In this case, if the angle θ and the connection length d between the nth set first flag portion 210 and the first electrode plate 215 are set without any organic relationship each time... n This could reduce the efficiency of the battery manufacturing process.

[0143] To prevent this, the length L from one end of the first electrode plate 215 closest to the central axis A to the nth first flag portion 210 arranged along the spiral direction is... n The length L of the first electrode plate 215 (refer to) Figure 7 When the first flag section 210 (or the nth set first flag section 210) and the first flag section 210 adjacent to the first flag section 210 are the same, the angle θ between the first flag section 210 and the first flag section 210 adjacent to the first flag section 210 and the connection length d between the first flag section 210 and the first electrode plate 215 are also considered. n It can be formed based on the aforementioned relation 1.

[0144] Therefore, even if the dimensions of the electrode assembly 20 change in the manufacturing process, the length d of the nth set first flag portion 210 can be directly calculated using the aforementioned formula 1. n Alternatively, based on the angle θ of the length of the nth set second flag portion 220, the manufacturing process of the electrode assembly 20 can reflect the length d of the nth set first flag portion 210. n The first electrode plate 215 and the second electrode plate 225 are manufactured using the angle θ.

[0145] As an example, the angle θ between any one of the first flag sections and the first flag section adjacent to the first flag section can be determined based on the length L of the first flag section set from the end closest to the central axis at both ends of the first electrode plate (n is a natural number). n And change.

[0146] Reference Figure 4 As an example, the angle θ1 of the first flag portion 210 located in R1 along the second direction with reference to the central axis A can be greater than the angle θ2 of the first flag portion 210 located in R2 along the second direction.

[0147] Furthermore, when the staggered angle relationship is used as described above, the angle between the second edge portion 217 of any first flag portion 210 and the first edge portion 216 of the first flag portion 210 adjacent to the first flag portion can be the two edges 216 and 217 of the first flag portion 210 (refer to...). Figure 5a The angle formed by the first edge portion 216 and the second edge portion 217 of any one of the first flag portions 210 with respect to the central axis A. Therefore, the angle formed by the first edge portion 216 and the second edge portion 217 of any one of the first flag portions 210 with respect to the central axis A can gradually increase as any one of the first flag portions 210 moves closer to the central axis A.

[0148] That is, the electrode assembly 20 according to this disclosure may include: a first electrode 21 including a plurality of first flags 210 extending from a first electrode plate 215 having an active material stacked on it; a second electrode 22 including a second electrode plate 225 having another active material stacked on it; and a diaphragm 25 disposed between the first electrode 21 and the second electrode 22, wherein the first electrode 21, the diaphragm 25 and the second electrode 22 may be wound around a virtual central axis A, and the plurality of first flags 210 may extend parallel to the central axis A.

[0149] Additionally, an electrode assembly 20 may be included, in which the angle between any one of the plurality of first flag portions 210 and another first flag portion 210 adjacent to the first flag portion is larger along the winding direction, i.e., the helical direction DR, of the first electrode 21 as it is closer to the central axis A.

[0150] As another example, the electrode assembly 20 according to this disclosure may include: a first electrode 21 including a first electrode plate 215 having an active material stacked on it and a plurality of first flags 210 extending from the first electrode plate 215 respectively; a second electrode 22 including a second electrode plate 225 having another active material stacked on it; and a diaphragm 25 disposed between the first electrode 21 and the second electrode 22, wherein the first electrode 21, the diaphragm 25 and the second electrode 22 may be wound around a virtual central axis A, and the plurality of first flags 210 may extend parallel to the central axis A respectively.

[0151] Additionally, along the winding direction of the first electrode 21, i.e., the helical direction DR, the first portion (First Portion) A1 (referring to) of the plurality of first flag portions 210 closest to the central axis A (see...) Figure 7 The angle between a pair of adjacent first flag portions 210 in the first portion A1 can be greater than that of a second portion (SecondPortion) A2, which is located further away from the central axis A than the first portion A1 (see reference). Figure 7 The angle between a pair of adjacent first flag sections 210 in the ().

[0152] As another example, the electrode assembly 20 according to this disclosure may include: a first electrode 21 including a plurality of first flags 210 extending from a first electrode plate 215 having an active material laminated thereon; a second electrode 22 including a second electrode plate 225 having another active material laminated thereon; and a diaphragm 25 disposed between the first electrode 21 and the second electrode 22. The first electrode 21, the diaphragm 25, and the second electrode 22 may be wound around a virtual central axis A, and each of the plurality of first flags 210 may include a first edge portion 216 extending obliquely relative to the central axis A and a second edge portion 217 extending parallel to the central axis A. Furthermore, each of the plurality of first flags 210 is bent such that the first edge portion 216 and the second edge portion 217 face the central axis A, such that the angle formed by the first edge portion 216 and the second edge portion 217 with respect to the central axis A can be larger along the winding direction of the first electrode 21, i.e., the helical direction DR, closer to the central axis A.

[0153] Therefore, the battery cell 100 according to this disclosure may include: housings 110 and 120 for accommodating the electrode assembly 20; a through hole (not shown) extending through one side of the housing along the central axis; and a terminal portion 130 inserted into the through hole and electrically connected to the electrode assembly 20 and the outside.

[0154] Figure 5aThis is an enlarged view of the first part of the first electrode adjacent to the central axis.

[0155] The first part A1 (refer to) Figure 7 The region along the spiral direction DR in the first electrode 21 is located closer to the central axis A than the outermost part of the housing 110, 120 or the electrode assembly 20.

[0156] The first electrode plate 215 may include: a first region 215a, and an active material 211 (see reference). Figure 3 The first electrode plate is stacked on the first region 215a and faces the diaphragm; and the second region 215b is formed between the plurality of first flags 210 and the first region 215a, and the first electrode plate is exposed and faces the diaphragm 25.

[0157] Reference Figure 5a Each of the plurality of first flag portions 210 may include: a first edge portion 216 extending obliquely relative to the first direction; a second edge portion 217 extending parallel to the first direction; a third edge portion 214 extending parallel to the spiral direction DR and connected to the first edge portion 216 and the second edge portion 217; and a connecting edge portion 213 connecting the plurality of first flag portions 210 and the second region 215b.

[0158] As described above, in this disclosure, the length of the connecting edge 213 along the spiral direction DR at the boundary where the second region 215b meets the connecting edge 213 is referred to as d.

[0159] The length of each connecting edge portion 213 of the plurality of first flag portions 210 may be the same.

[0160] In addition, in the first electrode plate 215, the height h of the plurality of first flag portions 210 along the central axis can be the same length as each other.

[0161] This is to optimize the overlap of the plurality of first flags 210 along the radial direction (or second direction) based on the central axis when bending the plurality of first flags 210, assuming the electrode assembly 20 is cylindrical. If the plurality of first flags 210 overlap excessively along the second direction, the step difference between the bent plurality of first flags 210 and the first current collector 141 will be severe, which may prevent uniform welding with the first current collector 141, and may ultimately cause structural stability problems in the electrode assembly 20 or the cell 100.

[0162] Furthermore, when any one of the plurality of first flag portions 210 according to this disclosure is bent, it can be prevented from overlapping with another first flag portion 210 disposed adjacent to that first flag portion 210 along the spiral direction. Therefore, among the plurality of first flag portions 210, the density of current per unit area flowing to the first current collector 141 can be reduced, thereby improving the heat generation problem generated during current movement.

[0163] That is, any one of the plurality of first flag portions 210 and the first flag portion 210 adjacent to the aforementioned first flag portion 210 can form a coplanar surface.

[0164] In this disclosure, coplanarity refers to a smooth or continuous surface formed by bending the first flag portions 210 adjacent to each other without any step difference when bending them along the spiral direction.

[0165] In addition, the first edge portion 216 may be closer to the central axis A along the spiral direction DR than the second edge portion 217.

[0166] On the other hand, in this disclosure, the angle formed by the first edge portion 216 and the second edge portion 217 of any one of the first flag portions 210 described in the first part A1 is referred to as the first angle θ1. When using the offset angle relationship, the first angle θ1 can be the angle formed by the first edge portion 216 of any one of the first flag portions 210 described in the first part A1 and the second edge portion 217 of another first flag portion 210 adjacent to the first flag portion 210.

[0167] Figure 5b This is an enlarged view of the second part of the first electrode, which is positioned further away from the central axis than the first part.

[0168] Part 2 A2 (refer to) Figure 7 The region A2 can be located closer to the housing 110, 120 or the outermost part of the electrode assembly 20 along the spiral direction DR of the first electrode 21 than the central axis A. Therefore, the second part A2 can be located further away from the central axis A than the first part A2.

[0169] As described above, the first electrode plate 215 may include a first region 215a on which the active material 211 is stacked and a second region 215b formed between the plurality of first flags 210 and the first region 215a.

[0170] Furthermore, in this disclosure, the angle formed by the first edge portion 216 and the second edge portion 217 of any one of the first flag portions 210 described in the second part A2 is referred to as the second angle θ2. Similarly, when using the offset angle relationship, the second angle θ2 can be the angle formed by the first edge portion 216 of any one of the first flag portions 210 described in the second part A2 and the second edge portion 217 of another first flag portion 210 adjacent to the first flag portion 210.

[0171] Reference Figure 5a and Figure 5b The first angle can be greater than the second angle. That is, along the spiral direction DR, the angle formed by the first edge portion 216 of any first flag portion 210 and the second edge portion 217 of another first flag portion 210 adjacent to the first flag portion 210 can be larger the closer it is to the central axis A.

[0172] The angle formed by the first edge portion 216 of any first flag portion 210 and the second edge portion 217 of the first flag portion 210 adjacent to the first flag portion 210 can gradually increase.

[0173] In contrast, the angle formed by the first edge portion 216 of any first flag portion 210 and the second edge portion 217 of another first flag portion 210 adjacent to the first flag portion 210 can also gradually increase in stages. That is, the spiral direction DR is divided into predetermined intervals, and the angle between the first flag portions 210 belonging to one interval is kept at the same second angle, while the angle between the first flag portions 210 belonging to another interval closer to the central axis A than the first interval can be kept at a first angle larger than the second angle.

[0174] As an example, the plurality of first flag sections 210 can be grouped in a predetermined number to form a plurality of first flag section groups. The angles between first flag sections 210 belonging to the same first flag section group can be the same, while the angles between first flag sections 210 belonging to different first flag section groups can be different.

[0175] That is, along the spiral direction, the angle between the first flags 210 belonging to any first flag group can be larger the closer it is to the central axis A.

[0176] Furthermore, the difference between the angle between a pair of adjacent first flag sections 210 in any first flag section group and the angle between a pair of adjacent first flag sections 210 in any first flag section group can be the same.

[0177] However, unlike this, the difference between the angle between a pair of adjacent first flags 210 in any first flag group and the angle between a pair of adjacent first flags 210 in any first flag group can be larger the closer to the central axis A.

[0178] Figure 6a The first flag section, which bends toward the central axis, is shown in the first part.

[0179] Reference Figure 3 and Figure 6a The plurality of first flag portions 210 may include a first surface 210a facing the central axis A and a second surface 210b facing in the opposite direction to the first surface 210a.

[0180] Therefore, after bending the plurality of first flag portions 210, the first surface 210a can face the first electrode plate 215, while the second surface 210b can be exposed to the outside or face the side of the housing 110, 120.

[0181] Reference Figure 4 and Figure 6a In the first part A1, the angle θ1 between any one of the first flag portions 210 and another first flag portion 210 adjacent to the first flag portion 210 can be the same as the angle between the two edge portions 216, 217 of the first flag portion 210 (refer to...). Figure 5a The angle between two points is mathematically called an alternate angle.

[0182] Figure 6b The first flag section, which bends toward the central axis, is shown in the second part.

[0183] Similarly, refer to Figure 4 and Figure 6b In the second part A2, the angle θ2 between any one of the first flag portions 210 and another first flag portion 210 adjacent to the first flag portion 210 can be related to the two edge portions 216, 217 of the first flag portion 210 (refer to...). Figure 5a The angle between two points is mathematically called an alternate angle.

[0184] Therefore, the angle formed by the two edge portions 216, 217 of any first flag portion 210 located in the first part A1 and the central axis A can be greater than the angle formed by the two edge portions 216, 217 of any first flag portion 210 located in the second part A2 and the central axis A.

[0185] Figure 7This is another example of the first electrode according to this disclosure.

[0186] Figure 7 An example of the first electrode 21 being unwound is shown. Along the helical direction DR, the side closer to the central axis is referred to as the central portion C, and the side closer to the outermost part of the electrode assembly 20 is referred to as the outer portion O.

[0187] As an example, the first part A1 may be a region closer to the center part C than the outer part O, and the second part A2 may be a region closer to the outer part O than the center part C.

[0188] Reference Figure 7 The height h1 of the second region 215b in the first part A1 adjacent to the central axis A can be less than the height h2 of the second region 215b in the second part A2 which is located further away from the central axis A than the first part A.

[0189] By setting different bending heights for any one of the first flag portions 210 located near the outer O, bending of any one of the first flag portions 210 located near the outer O can be made easier.

[0190] That is, when the plurality of first flag portions 210 bend toward the central axis A, the first flag portion 210 closest to the center portion C or the central axis A can be bent first, and then the first flag portion 210 closest to the outer edge O can be bent. Therefore, after the first flag portion 210 closest to the outer edge O is bent, in order to maintain the bent shape and facilitate assembly, it is necessary to increase the height of the first flag portion 210 closest to the outer edge O in the direction parallel to the central axis A compared to the first flag portion 210 closest to the central axis A.

[0191] The length of the second region 215b can change gradually, or it can change in stages. That is, the length of the second region 215b can be constant in one interval and change in another interval.

[0192] Furthermore, along the winding direction of the first electrode 21, i.e. the helical direction, the angle between a pair of adjacent first flags 210 in the first portion A1 adjacent to the central axis A among the plurality of first flags 210 can be greater than the angle between a pair of adjacent first flags 210 in the second portion A2 which is disposed further away from the central axis A than the first portion A1.

[0193] That is, from the second part A2 to the first part A1, the angle between a pair of adjacent first flag parts 210 among the plurality of first flag parts 210 can be increased.

[0194] In one embodiment, the plurality of first flag parts 210 can be divided into a plurality of first flag part groups, which are formed by grouping adjacent first flag parts 210 in a predetermined number. The angle between a pair of first flag parts 210 in the same first flag part group can be the same, and the angle between a pair of first flag parts 210 in any first flag part group can increase from the second part A2 to the first part A1.

[0195] As described above, when comparing the angle between the first-1 flag section 2101 and the first-2 flag section 2102 that are adjacent to each other in the first part A1 with the angle between the first-3 flag section 2103 and the first-4 flag section 2104 that are adjacent to each other in the second part A2, the angle between the first-1 flag section 2101 and the first-2 flag section 2102 can be greater than the angle between the first-3 flag section 2103 and the first-4 flag section 2104.

[0196] Specifically, Figure 7 The diagram shows a first-1 flag section 2101, a first-2 flag section 2102 adjacent to the first-1 flag section 2101 and positioned further away from the central axis A along the spiral direction DR than the first-1 flag section 2101, a first-3 flag section 2103 positioned further away from the central axis A along the spiral direction DR than the first-2 flag section 2102, and a first-4 flag section 2104 adjacent to the first-3 flag section 2103 and positioned further away from the central axis A along the spiral direction DR than the first-3 flag section 2103. However, this is only an example, and the positions of the first-1 flag section 2101, the first-2 flag section 2102, the first-3 flag section 2103, and the first-4 flag section 2104 are not limited to this.

[0197] In addition, the first angle θ1 between the first-1 flag section 2101 and the first-2 flag section 2102 can be greater than the second angle θ2 between the first-3 flag section 2103 and the first-4 flag section 2104.

[0198] This disclosure can be implemented in various forms, and its scope of rights is not limited to the embodiments described above. Therefore, if a modified embodiment includes components within the scope of the claims of this disclosure, it should be considered to fall within the scope of this disclosure.

Claims

1. An electrode assembly, comprising: The first electrode includes a plurality of first flags, each of which extends from a first electrode plate having an active material stacked on it. The second electrode includes a second electrode plate on which another active material is stacked. as well as A diaphragm is disposed between the first electrode and the second electrode. The first electrode, the diaphragm, and the second electrode are wound around a virtual central axis. The plurality of first flag sections extend parallel to the central axis, and the angle between any one of the plurality of first flag sections and another first flag section adjacent to the first flag section increases as the spiral direction of the first electrode approaches the central axis.

2. The electrode assembly according to claim 1, wherein, The second electrode further includes: Multiple second flags extend from the second electrode plate in the opposite direction to the direction in which the multiple first flags extend, and bend toward the central axis.

3. The electrode assembly according to claim 1, wherein, The first electrode plate includes: A first region, wherein an active substance is stacked on the first region and faces the membrane; and A second region is formed between the plurality of first flags and the first region, and the first electrode plate is exposed and faces the diaphragm.

4. The electrode assembly according to claim 3, wherein, The height (h1) of the second region in the first part adjacent to the central axis is less than the height (h2) of the second region in the second part that is further away from the central axis than the first part.

5. The electrode assembly according to claim 3, wherein, Each of the plurality of first banner units includes: The first edge portion extends obliquely relative to the central axis; The second edge extends parallel to the central axis; The third edge portion is connected to the first edge portion and the second edge portion along the spiral direction; and Connect the edge portion, connecting the plurality of first flag portions and the second region.

6. The electrode assembly according to claim 5, wherein, The angle is the angle between the second edge of any first flag section and the first edge of the first flag section adjacent to any first flag section.

7. The electrode assembly according to claim 5, wherein, The lengths of the connecting edges of the plurality of first flags are the same.

8. The electrode assembly according to claim 5, wherein, The first edge portion is closer to the central axis along the spiral direction than the second edge portion.

9. The electrode assembly according to claim 1, wherein, The heights of the multiple first flag units are the same.

10. The electrode assembly according to claim 1, wherein, The angle (θ) between any one of the first flag sections and the first flag section adjacent to the stated first flag section satisfies the following relationship 1. [Relation 1] ， In the relation 1, L n R represents the length from one end of the first electrode plate closest to the central axis to the nth first flag section. o d represents the radius of the end of the first electrode plate wound around the central axis that is closer to the central axis. n The length of the connection between the nth set first flag and the first electrode plate is denoted by t, and the sum of the thicknesses of the first electrode, the second electrode and the diaphragm is denoted by t, where n is a natural number.

11. The electrode assembly according to claim 1, wherein, The angle (θ) between any one of the first flag sections and the first flag section adjacent to the first flag section is determined by the length (L) from the end of the first electrode plate closest to the central axis to the nth set first flag section. n The value changes, where n is a natural number.

12. An electrode assembly, comprising: The first electrode includes a plurality of first flags, each of which extends from a first electrode plate having an active material stacked on it. The second electrode includes a second electrode plate on which another active material is stacked. as well as A diaphragm is disposed between the first electrode and the second electrode. The first electrode, the diaphragm, and the second electrode are wound around a virtual central axis. The plurality of first flag portions extend parallel to the central axis and along the winding direction of the first electrode, i.e., the helical direction. The angle between a pair of adjacent first flag portions in the first portion adjacent to the central axis is greater than the angle between a pair of adjacent first flag portions in the second portion further away from the central axis than the first portion.

13. The electrode assembly according to claim 12, wherein, From the second part toward the first part, the angle between a pair of adjacent first flags among the plurality of first flags increases.

14. The electrode assembly according to claim 12, wherein, The plurality of first flag sections are divided into a plurality of first flag section groups, which are formed by grouping adjacent first flag sections into a predetermined number. This includes the fact that the angle between a pair of first flags in the same first flag group is the same. The angle between a pair of first flags in any first flag group is larger the closer it is to the central axis.

15. An electrode assembly, comprising: The first electrode includes a plurality of first flags, each of which extends from a first electrode plate having an active material stacked on it. The second electrode includes a second electrode plate on which another active material is stacked. as well as A diaphragm is disposed between the first electrode and the second electrode. The first electrode, the diaphragm, and the second electrode are wound around a virtual central axis. Each of the plurality of first banner units includes: The first edge portion extends obliquely relative to the central axis; as well as The second edge portion extends parallel to the central axis. Each of the plurality of first flag portions is bent so that the first edge portion and the second edge portion face the central axis, thereby making the angle formed by the first edge portion and the second edge portion with respect to the central axis larger as the first electrode is wound in the spiral direction (i.e., the direction of the helix) closer to the central axis.

16. The electrode assembly of claim 15, further comprising: The first current collector is electrically connected to the plurality of first flag sections and terminal sections.

17. The electrode assembly of claim 16, wherein, The plurality of first flag sections are joined to the first current collector by welding.

18. The electrode assembly of claim 16, further comprising: The second current collector is located on the opposite side of the first current collector and is electrically connected to the second electrode. The first electrode, the second electrode, and the diaphragm are sandwiched between the first current collector and the second current collector.

19. The electrode assembly according to claim 18, wherein, The second electrode further includes: Multiple second flags extend from the second electrode plate in a direction opposite to the extending direction of the multiple first flags. The plurality of second flags bend toward the central axis and are electrically connected to the second current collector.

20. The electrode assembly according to claim 15, wherein, Any one of the plurality of first flag sections and another first flag section adjacent to the stated first flag section are bent to form a coplanarity.

21. A battery cell, comprising: Electrode assembly according to any one of claims 1, 12, and 15; A housing for accommodating the electrode assembly; A through hole extending through one side of the housing along the central axis; and The terminal portion is inserted into the through hole to electrically connect the electrode assembly to the outside.

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