battery cells

Abstract

The present invention provides a battery cell having a structure that prevents the negative electrode plate and the positive electrode plate from short-circuiting each other even if a shrinkage phenomenon of the separation membrane occurs in a high-temperature environment, and also provides a battery cell that can solve the problem of the battery cell's capacity decreasing due to an insulating region formed on the electrode plates. The battery cell includes one or more first electrode plates, one or more second electrode plates having the opposite polarity to one or more first electrode plates, one or more separation membranes disposed between one or more first electrode plates and one or more second electrode plates, and one or more insulating members placed on one or more first electrode plates, wherein one or more insulating members include a non-adhesive surface that contacts one or more first electrode plates.

Description

Technical Field

[0001] The present invention relates to a battery cell.

Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged and can be applied to various fields such as digital cameras, mobile phones, notebook computers, hybrid vehicles, and electric vehicles. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and recently, lithium-ion batteries have been widely used.

[0003] Generally, a secondary battery such as a lithium-ion battery (hereinafter referred to as a battery cell) may have a structure in which an electrode assembly in which one or more positive electrode plates and one or more negative electrode plates are alternately stacked with a separator interposed therebetween is housed inside a case.

[0004] During the charge and discharge process of the battery cell, the temperature inside the battery cell rises. However, when the internal temperature increases above a certain level (for example, a temperature of 130 °C or higher), the phenomenon that the separator that separates the negative electrode and the positive electrode shrinks frequently occurs. In this case, as the separator shrinks, the negative electrode and the positive electrode come into contact with each other, and there is a risk of electrical short circuit and ignition and explosion phenomena.

[0005] Particularly, in the case of a lithium-sulfur battery (Li-S battery) or a lithium-metal battery (Li-Metal battery), which are next-generation batteries, the negative electrode can be made of lithium metal itself. In this case, when the phenomenon of shrinkage of the separator occurs, highly reactive lithium metal contacts the electrode plate of the opposite polarity, causing a problem of triggering a thermal runaway phenomenon of the battery cell.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention was devised to solve at least some of the problems of the prior art described above, and provides a battery cell having a structure in which the negative electrode plate and the positive electrode plate are not short-circuited to each other even when a shrinkage phenomenon of the separation membrane occurs in a high-temperature environment (for example, 130°C).

[0007] Furthermore, the present invention provides a battery cell that can solve the problem of reduced battery cell capacity due to insulating regions formed on the electrode plates. [Means for solving the problem]

[0008] To achieve the above objectives, an embodiment provides a battery cell comprising one or more first electrode plates, one or more second electrode plates having the opposite polarity to the one or more first electrode plates, one or more separator membranes disposed between the one or more first electrode plates and the one or more second electrode plates, and one or more insulating members placed on the one or more first electrode plates, wherein the one or more insulating members include a non-adhesive surface that contacts the one or more first electrode plates.

[0009] In the embodiment, at least a portion of one or more first electrode plates may be made of lithium or a lithium-containing alloy.

[0010] In the embodiment, the non-adhesive surfaces of one or more insulating members may come into contact with portions made of lithium or a lithium-containing alloy on one or more first electrode plates.

[0011] In the embodiment, in one or more insulating members, the portions that come into contact with one or more first electrode plates may all consist of non-adhesive surfaces.

[0012] In the embodiment, the insulating member may consist of at least one of polyimide, polypropylene, polyvinyl chloride, polyester, polyacetal, polyolefin, and polyethylene.

[0013] In the embodiment, one or more first electrode plates include one or more mask portions on which one or more insulating members are placed, and exposed portions exposed to the separation film, wherein one or more mask portions may be formed along at least one edge of one or more first electrode plates.

[0014] In the embodiment, one or more insulating members may have a loop-shaped structure in which a first insulating portion facing one surface of one or more first electrode plates and a second insulating portion facing the opposite surface of one surface are continuously connected.

[0015] In the embodiment, one or more insulating members may include a first insulating member positioned along a first edge from which an electrode tab protrudes from a first electrode plate, and a second insulating member positioned along a second edge opposite the first edge of the first electrode plate.

[0016] In embodiments, one or more insulating members further include a third insulating member and a fourth insulating member, which are positioned along third and fourth edges connected to a first and second edge, respectively, on a first electrode plate, wherein one end of each of the first to fourth insulating members covers a portion of another insulating member adjacent to that end, and the opposite end of each of the first to fourth insulating members may be covered by another insulating member adjacent to that end.

[0017] In this embodiment, adhesive material may not be applied to the portion of one or more insulating members that comes into contact with one or more mask portions.

[0018] In the embodiment, one or more insulating members include a fifth insulating member facing one surface of one or more first electrode plates and a sixth insulating member facing the opposite surface of one or more first electrode plates, wherein the fifth insulating member and the sixth insulating member can be separated from each other.

[0019] In the embodiment, the fifth insulating member and the sixth insulating member may have a frame-like structure that surrounds the exposed portion.

[0020] In an embodiment, the first electrode plate and the second electrode plate are arranged to face one surface and the opposite surface of a separator folded in a zigzag manner, and the one or more insulating members may include a first insulating member and a second insulating member that are respectively arranged along two edge portions of the first electrode plate and are spaced apart from each other in the width direction of the separator.

Advantages of the Invention

[0021] According to an embodiment, a battery cell having a structure in which a negative electrode plate and a positive electrode plate are not short-circuited with each other can be realized even when a shrinkage phenomenon of the separator occurs in an environment at a high temperature (particularly, 130 °C).

[0022] Also, according to an embodiment, a battery cell can be provided in which the capacity of the battery cell does not decrease even when a mask portion is formed in at least a part of a region of the electrode plate so as not to be short-circuited with an electrode plate having an opposite polarity.

Brief Description of the Drawings

[0023] [Figure 1] It is an exploded perspective view of a battery cell according to an embodiment. [Figure 2] It is a reference diagram showing the configuration of an electrode assembly included in a battery cell. [Figure 3] \nIt is an exemplary cross-sectional view taken along the line I-I' of FIG. 2. \n \n [Figure 4] \nIt is an exploded perspective view of a first electrode plate assembly according to an embodiment. \n \n [Figure 5] \nIt is an exploded perspective view of a first electrode plate assembly according to another embodiment. \n \n [Figure 6] \nIt is a reference diagram showing the configuration of an electrode assembly according to another embodiment. \n \n [Figure 7] \nIt is an exploded perspective view of the first electrode plate assembly shown in FIG. 6. \n \n [Figure 8] \nIt is a graph showing the temperature change of each electrode assembly when the electrode assembly according to the embodiment and the electrode assembly according to the first comparative example are heated. \n \n [Figure 9]This graph shows the test results of the capacity performance of a battery cell including the electrode assembly according to the embodiment and a battery cell including the electrode assembly according to the second comparative example. [Figure 10] This graph shows the temperature changes of the electrode assemblies according to the embodiment and the electrode assemblies according to the second comparative example when they are heated. [Modes for carrying out the invention]

[0024] Prior to a detailed description of the present invention, terms or words used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical spirit of the invention, in accordance with the principle that inventors may appropriately define terms as concepts in order to best describe their invention. Accordingly, the embodiments described herein and the configurations shown in the drawings represent only the most preferred embodiments of the invention and do not represent the entire technical spirit of the invention; therefore, it should be understood that, at the time of filing, there may be a variety of equivalents and modifications that can substitute for them.

[0025] The same reference numerals or symbols in the drawings attached to this specification indicate parts or components that perform substantially the same function. For convenience of explanation and understanding, the same reference numerals or symbols may be used to describe different embodiments. That is, even if multiple drawings show components with the same reference numeral, not all of the multiple drawings represent a single embodiment.

[0026] In the following descriptions, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as “contains” or “constitutes” are intended to specify the presence of features, figures, stages, actions, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the presence or possibility of the addition of one or more other features, figures, stages, actions, components, parts, or combinations thereof.

[0027] Furthermore, in the following explanation, terms such as "top," "upper," "lower," "bottom," "side," "front," and "rear" are used based on the direction shown in the drawing, and it should be made clear beforehand that they may be used differently if the direction of the object changes.

[0028] Furthermore, within this specification and the claims, terms including ordinal numbers, such as "first," "second," etc., may be used to distinguish between components. Such ordinal numbers are used to distinguish identical or similar components from one another, and the use of such ordinal numbers should not restrict the meaning of the terms. For example, components combined with such ordinal numbers should not be restricted in terms of their order of use or arrangement by the numbers. Where necessary, the ordinal numbers may be used interchangeably with each other.

[0029] Embodiments of the present invention will be described below with reference to the attached drawings. However, the spirit of the present invention is not limited to the embodiments presented. For example, a person skilled in the art who understands the spirit of the present invention may propose other embodiments that fall within the scope of the spirit of the present invention by adding, changing, or deleting components, and these too shall be considered to fall within the scope of the spirit of the present invention. In the drawings, the shape and size of elements, etc., may be exaggerated for clearer explanation.

[0030] First, the configuration of a battery cell according to one embodiment will be described with reference to Figures 1 to 3.

[0031] Figure 1 is an exploded perspective view of a battery cell 1 according to an embodiment.

[0032] Figure 2 is a reference diagram showing an exemplary configuration of the electrode assembly 10 included in the battery cell (1 in Figure 1).

[0033] Figure 3 is an exemplary cross-sectional view along section I-I' in Figure 2.

[0034] Referring to Figure 1, the battery cell 1 according to this embodiment may include an electrode assembly 10 in which a plurality of electrode plates are stacked, a case 30 in which the electrode assembly 10 is housed, and lead tabs 20 that are electrically connected to the electrode assembly 10 and a portion of which is exposed to the outside of the case 30.

[0035] The case 30 may include an electrode housing section 33 in which the electrode assembly 10 is housed and a sealing section 34 positioned along the edge of the electrode housing section 33. The electrode housing section 33 may be formed by joining an upper case 32 and a lower case 31 vertically and have an internal space in which the electrode assembly 10 is housed. The sealing section 34 is formed by crimping or heat-sealing the edges of the upper case 32 and the lower case 31 along the edge of the electrode housing section 33, and can block foreign matter and moisture from outside the case 30 from flowing into the electrode assembly 10 housed inside the electrode housing section 33.

[0036] The case 30 may be a pouch-type case 30 made of a ductile material. For example, the case 30 may be made of an aluminum laminate sheet. However, the case 30 of the battery cell 1 according to this embodiment may also be composed of a rectangular case or a cylindrical case made of a metal material such as aluminum, in addition to the pouch-type case 30 described above.

[0037] Referring to Figure 2, the electrode assembly 10 may have a structure in which a large number of first electrode plates 110 and a large number of second electrode plates 200 having opposite polarities are stacked with a separation membrane 300 in between. However, what is shown in Figure 2 is only a part of the first electrode plates 110, second electrode plates 200, and separation membrane 300 included in the electrode assembly 10, and the actual electrode assembly 10 may have a much larger number of first electrode plates 110, second electrode plates 200, and separation membrane 300 than what is shown in Figure 2.

[0038] The separation membrane 300 is interposed between the first electrode plate 110 and the second electrode plate 200, preventing an electrical short circuit between the first electrode plate 110 and the second electrode plate 200, and may be configured to be impregnated with an electrolyte so that ions can pass through. The separation membrane 300 may be made of a porous polymer film or a porous nonwoven fabric, etc. However, the material of the separation membrane 300 can be any material that is commonly used in lithium secondary batteries, in addition to the materials mentioned above, without any special restrictions.

[0039] The first electrode plate 110 and the second electrode plate 200 may be provided with electrode tabs 112 and 210, respectively. In the following description, the electrode tab 112 of the first electrode plate 110 is defined as the first electrode tab 112, and the electrode tab 210 of the second electrode plate 200 is defined as the second electrode tab 210.

[0040] In the electrode assembly 10, multiple first electrode tabs 112 and second electrode tabs 210 may be provided. Multiple electrode tabs 112 and 210 can come together with those of the same polarity to form an electrode tab bundle ET. Lead tabs 20, which act as terminals in the battery cell 1, may be connected to the electrode tab bundle ET, thereby electrically connecting the electrode assembly 10 and the lead tabs 20. Various welding methods, including ultrasonic welding, or physical fastening methods such as rivets may be applied to connect the electrode tab bundle ET and the lead tabs 20.

[0041] The lead tab 20 may be made of a conductive metallic material. For example, the lead tab 20 may be made of nickel (Ni), copper (Cu), nickel-plated copper, aluminum (Al), etc. A sealing member 21 may be placed between the lead tab 20 and the case 30. For example, the sealing member 21 may be made of a material that has both insulating and adhesive properties, and may be joined to the sealing portion 34 of the case 30 while covering a portion of the lead tab 20, thereby ensuring electrical insulation between the lead tab 20 and the case 30 and sealing the space between the lead tab 20 and the sealing portion 34.

[0042] In this embodiment, the first electrode plate 110 and the second electrode plate 200 of the electrode assembly 10 may be electrodes with opposite polarities. For example, if the first electrode plate 110 is a negative electrode plate, the second electrode plate 200 may be a positive electrode plate.

[0043] The positive electrode plate may have a structure in which a positive electrode active material layer 202 is formed on a current collector 201. For example, referring to Figure 2, the second electrode plate 200 may be a positive electrode plate, and can be formed by coating a mixture of positive electrode active material, conductive material, and binder onto a current collector 201 made of an aluminum alloy material. In this case, the materials for the positive electrode active material, binder, conductive material, and current collector 201 can be any known materials used in the positive electrode plates of lithium secondary batteries.

[0044] Unlike conventional negative electrode plates, the negative electrode plate of the battery cell 1 according to this embodiment may be made of a metal sheet formed of lithium or a lithium-containing alloy (hereinafter simply referred to as "lithium metal").

[0045] Conventionally, a negative electrode plate may have a structure in which a negative electrode active material layer is formed on a current collector. For example, a negative electrode plate may be formed by coating a mixture of negative electrode active material, conductive material, and binder onto a current collector made of a copper alloy material.

[0046] In contrast, the negative electrode plate of the battery cell 1 according to this embodiment may have an integrated structure consisting of an electrode plate body made of a lithium metal sheet and an electrode tab arranged on one side of the electrode plate body. A battery cell 1 to which a negative electrode plate made of a lithium metal sheet is applied can omit a conventional negative electrode current collector made of nickel (Ni), aluminum (Al), copper (Cu), etc., which is advantageous not only for reducing the weight of the battery cell 1 but can also have a very high energy density.

[0047] The first electrode plate 110 and the second electrode plate 200 are separated by the separation membrane 300, allowing them to maintain a state where they do not come into contact with each other.

[0048] However, the separation membrane 300 frequently shrinks at high temperatures, for example, around 130°C. This can cause the first electrode plate 110 and the second electrode plate 200 to come into contact with each other beyond the edge of the shrunk separation membrane 300, potentially resulting in a short circuit. If the first electrode plate 110 and the second electrode plate 200 are short-circuited, the temperature of the electrode assembly 10 may rise rapidly, potentially generating a flame, which could cause thermal runaway in the battery cell 1.

[0049] Therefore, to prevent the first electrode plate 110 and the second electrode plate 200 from coming into contact with each other even if the separator membrane 300 shrinks, the battery cell 1 according to this embodiment may further include one or more insulating members 120 arranged along at least one edge of the first electrode plate 110. For example, referring to Figures 2 and 3, the insulating member 120 may be positioned between the first electrode plate 110 and the separator membrane 300 near at least one edge of the first electrode plate 110.

[0050] The insulating member 120 is made of an insulating material and is placed on the first electrode plate 110, and can prevent the first electrode plate 110 and the second electrode plate 200 from coming into contact with each other beyond the edge of the contracted separation membrane 300 and short-circuiting.

[0051] The insulating member 120 may consist of a polymer film. For example, the insulating member 120 may consist of at least one of polyimide, polypropylene, polyvinyl chloride, polyester, polyacetal, polyolefin, and polyethylene. However, the material of the insulating member 120 is not limited to those mentioned above, and may consist of any material that can be placed between two different electrode plates and electrically insulate them.

[0052] In this embodiment, the insulating member 120 is placed on the first electrode plate 110 and together with the first electrode plate 110 can form a first electrode plate assembly 100. That is, the electrode assembly 10 according to this embodiment may have a structure in which the first electrode plate assembly 100 and the second electrode plate 200 are alternately stacked with a separation membrane 300 in between.

[0053] In conventional battery cells, an insulating region could be formed on the edges of the electrode plates by covering them with an insulating material. However, in this case, the insulating region was formed by either applying an insulating coating slurry onto the electrode plates or by attaching an insulating film to the electrode plates.

[0054] This method of forming an insulating region resulted in the insulating region of the electrode plate being covered by a slurry containing binder components or an adhesive substance for an insulating film, making it difficult for it to participate in the battery reaction, which led to a problem of reduced overall battery cell capacity.

[0055] Furthermore, when some of the electrode plates constituting the electrode assembly are made of lithium metal, the high reactivity of lithium makes it difficult to apply the slurry for the insulating coating layer or to stably attach an insulating film containing an adhesive.

[0056] In contrast, the battery cell 1 according to this embodiment includes an insulating member 120 in which at least a portion of the part that contacts the first electrode plate 110 is composed of a non-adhesive surface, thereby preventing the edge of the first electrode plate 110 from coming into contact with the second electrode plate 200, while simultaneously solving the aforementioned problems.

[0057] In the following section, the first electrode plate assembly 100, including the insulating member 120 according to the embodiment, will be described in more detail with reference to Figure 4.

[0058] Figure 4 is an exploded perspective view of the first electrode plate assembly 100 according to one embodiment.

[0059] The first electrode plate assembly 100 described in Figure 4 includes all the features of the first electrode plate assembly 100 described in Figures 1 to 3; therefore, explanations that overlap with those in Figures 1 to 3 can be omitted.

[0060] The first electrode plate assembly 100 may include the first electrode plate 110 and one or more insulating members 120 disposed on the first electrode plate 110.

[0061] The first electrode plate 110 may include an electrode plate body portion 111 that faces the second electrode plate 200 across the separation membrane 300, and a first electrode tab 112 that protrudes from the electrode plate body portion 111 and is connected to the lead tab 20.

[0062] As explained with reference to Figures 1 to 3, the first electrode plate 110 may be made of a lithium metal sheet. For example, the electrode plate body portion 111 and the first electrode tab 112 of the first electrode plate 110 may both be made of a lithium metal sheet. The technical advantages of making the first electrode plate 110 from a lithium metal sheet can be found in the explanation with reference to Figures 1 to 3.

[0063] The first electrode plate assembly 100 may include one or more insulating members 120 that cover a portion of the first electrode plate 110. For example, referring to Figure 4, the insulating member 120 may be an insulating film provided in a loop-shaped structure so as to surround and cover the vicinity of one edge of the electrode plate body portion 111. Here, the loop-shaped structure may mean a structure in which a first insulating portion 121 facing one surface of the electrode plate body portion 111 and a second insulating portion 122 facing the opposite surface of the electrode plate body portion 111 are continuously connected at both ends in the longitudinal direction. For example, the loop-shaped structure may be formed by folding a long strip of insulating film and connecting one end of the insulating film to the other end. As a result, the loop-shaped insulating member 120 may have a structure in which it is continuously connected in the longitudinal direction {for example, in the X-axis direction with respect to the first insulating member 120a, or in the Y-axis direction with respect to the third insulating member 120c}, and has slits or holes in the width direction {for example, in the Y-axis direction with respect to the first insulating member 120a, or in the X-axis direction with respect to the third insulating member 120c} into which the first electrode plate 110 can be inserted.

[0064] Alternatively, the loop-shaped insulating member 120 may be formed by joining two rectangular sheets of the same shape at both ends in the longitudinal direction, or it may be realized through a process of molding a polymer resin material, which is the raw material for the insulating member 120, into a ring shape.

[0065] However, the shape, structure, and manufacturing method of the insulating member 120 are not limited to those shown in the drawings and described above. The insulating member 120 may have any structure as long as it can stably cover a portion of the electrode plate body portion 111.

[0066] In a single first electrode plate assembly 100, multiple insulating members 120 may be provided. For example, as shown in Figure 4, the first electrode plate assembly 100 may include four insulating members 120a, 120b, 120c, and 120d arranged along the four edges of the electrode plate body portion 111.

[0067] By covering a portion of the electrode plate body portion 111 with the insulating member 120, the electrode plate body portion 111 can be divided into a mask portion 111a covered by the insulating member 120 and an exposed portion 111b that is directly exposed to the separation membrane 300 without being covered by the insulating member 120.

[0068] The mask portion 111a corresponds to the position where the insulating member 120 is placed and may be formed along at least one edge of the electrode plate body portion 111. For example, referring to Figure 4, by arranging the first to fourth insulating members 120a, 120b, 120c, and 120d along the four edges of the electrode plate body portion 111, the mask portion 111a may be formed along the four edges of the electrode plate body portion 111, with the exposed portion 111b formed between them.

[0069] However, the mask portion 111a differs from the exposed portion 111b only in that it is covered by the insulating member 120, and its material composition may be the same as that of the exposed portion 111b.

[0070] In the insulating member 120, at least a portion of the part facing the mask portion 111a may consist of a non-adhesive surface NA where no adhesive material is present. For example, in the loop-shaped insulating member 120 shown in Figure 4, the inner surface that can come into contact with the mask portion 111a of the first electrode plate 110 may all be composed of a non-adhesive surface NA. As a result, the insulating member 120 can be placed on the first electrode plate 110 in a state where it is in contact with the mask portion 111a but is not adhered to it.

[0071] In this way, by configuring the portion that contacts the first electrode plate 110 with a non-adhesive surface NA, there is no need for a separate adhesive material to be present on the mask portion 111a of the first electrode plate 110.

[0072] In particular, when the first electrode plate 110 is made of a lithium metal with high reactivity, the adhesive material may come into contact with the lithium, preventing the lithium in that area from participating in the battery reaction or contaminating the lithium. However, the insulating member 120 according to this embodiment is placed on the lithium metal of the first electrode plate 110 via a non-adhesive surface NA, thereby preventing such problems from occurring.

[0073] In other words, the insulating member 120 according to the embodiment is placed on the mask portion 111a of the first electrode plate 110 via the non-adhesive surface NA, preventing the first electrode plate 110 and the second electrode plate 200 from coming into contact and short-circuiting when the separation membrane 300 contracts, and at the same time preventing the reactivity of the first electrode plate 110 from decreasing due to the insulating member 120. As a result, the entire area of ​​the electrode plate body portion 111 of the first electrode plate 110 can participate in the battery reaction, thus preventing a decrease in the capacity of the battery cell 1 and maximizing the energy density of the battery cell 1.

[0074] Furthermore, since the portion of the insulating member 120 that contacts the mask portion 111a is composed of a non-adhesive surface NA, the process of assembling the insulating member 120 and the first electrode plate 110 can be performed more quickly and easily compared to the conventional process of applying slurry or attaching an adhesive insulating film. For example, if the insulating member 120 has a loop-shaped structure as shown in Figure 4, the insulating member 120 can be simply fitted onto the edge of the first electrode plate 110 and its position adjusted to easily form the mask portion 111a. In this case, there is also the advantage that the mask portion 111a can be easily formed on both sides near one side of the edge of the first electrode plate 110 via a single loop-shaped insulating member 120.

[0075] On the other hand, even if there is no adhesive substance in the portion of the insulating member 120 that comes into contact with the first electrode plate 110, the insulating member 120 can stably maintain its position on the mask portion 111a of the first electrode plate 110 due to the lamination pressure formed during the lamination process of the electrode assembly 10.

[0076] When multiple insulating members 120 are provided, one insulating member (e.g., 120a) can cover a portion of another insulating member (e.g., 120d). For example, referring to Figures 2 and 4 together, the first electrode plate assembly 100 may include a first insulating member 120a positioned along one edge (hereinafter referred to as the first edge) on which the electrode tab 112 protrudes in the electrode plate body portion 111, a second insulating member 120b positioned along the edge opposite the first edge (hereinafter referred to as the second edge), a third insulating member 120c positioned along two edges (hereinafter referred to as the third edge and the fourth edge) connected to the first edge and the second edge, respectively, and a fourth insulating member 120d. In this case, as shown in Figure 2, the multiple insulating members 120a, 120b, 120c, and 120d may be arranged to sequentially cover parts of other insulating members 120 adjacent to each other in a clockwise (or counterclockwise) direction. That is, the first insulating member 120a may be arranged to cover a part of the fourth insulating member 120d, the fourth insulating member 120d to cover a part of the second insulating member 120b, the second insulating member 120b to cover a part of the third insulating member 120c, and the third insulating member 120c to cover a part of the first insulating member 120a.

[0077] Thus, a structure in which one insulating member 120 covers a portion of another adjacent insulating member 120 is defined as a "cross-arrangement structure".

[0078] According to the cross-arrangement structure, each insulating member 120 positioned at the four edges of the electrode plate body portion 111 makes cross-contact with each other, forming a stable arrangement structure. That is, the end of any one insulating member 120 covers a portion of the surface of an adjacent insulating member 120, preventing that insulating member 120 from detaching from its predetermined position. At the same time, while the electrode assemblies 10 are stacked and assembled, the insulating members 120 come into contact with each other, stably maintaining a state of covering the mask portion 111a. Furthermore, the insulating members 120 at the four edges of the electrode plate body portion 111 intersect with each other in a clockwise direction, repeating the same structure, and as a large number of first electrode plate assemblies 100 are stacked, structural imbalances can be prevented.

[0079] However, the cross-arrangement structure of the insulating members 120 is not limited to that shown in Figure 2. For example, unlike in Figure 2, a counterclockwise cross-arrangement structure is also possible, or a cross-arrangement structure in which any one of the first to fourth insulating members 120a, 120b, 120c, and 120d does not cover the other insulating members is also possible.

[0080] Alternatively, in other embodiments, the insulating member may be provided in a variety of other shapes in addition to the loop-shaped structure described above. A first electrode plate assembly to which such other types of insulating members are applied will be described below with reference to Figure 5.

[0081] Figure 5 is an exploded perspective view of the first electrode plate assembly 100' according to another embodiment.

[0082] In the first electrode plate assembly 100' according to the embodiment described in Figure 5, in addition to the shape of the insulating member 120', other features are the same as those of the first electrode plate assembly 100 described in Figures 1 to 4, so redundant explanations can be omitted.

[0083] The first electrode plate assembly 100' may include a plurality of insulating members 120' placed on one side and the other side of the first electrode plate 110, respectively. For example, as shown in Figure 5, a fifth insulating member 120e having a frame-like structure may be placed on one side of the first electrode plate 110, and a sixth insulating member 120f having a frame-like structure may be placed on the opposite side of the first electrode plate 110.

[0084] In the process of stacking and assembling the electrode assembly, the fifth insulating member 120e and the sixth insulating member 120f are stacked sequentially so that the first electrode plate 110 is positioned between them, and the stacking pressure of the electrode assembly allows the first electrode plate 110 to maintain its position on the mask portion 111a.

[0085] The fifth insulating member 120e and the sixth insulating member 120f differ only in shape from the first to fourth insulating members 120a, 120b, 120c, and 120d described in Figures 1 to 4, while all other features, such as the material and the arrangement of the non-adhesive surface NA, are identical. For example, in the fifth insulating member 120e and the sixth insulating member 120f, at least a portion of the part that contacts the first electrode plate 110 may consist of a non-adhesive surface NA, and the technical effects of this can be seen by referring to the explanation for Figures 1 to 4.

[0086] On the other hand, in other embodiments, the electrode assembly may have a structure in which the first electrode plate assembly and the second electrode plate are separated from each other by a continuous separation membrane that is bent in a zigzag pattern. Below, an electrode assembly according to another embodiment will be described with reference to Figures 6 and 7.

[0087] Figure 6 is a reference diagram showing the configuration of the electrode assembly 10" according to another embodiment.

[0088] Figure 7 is an exploded perspective view of the first electrode plate assembly 100'' shown in Figure 6.

[0089] Referring to Figure 6, in the manufacturing process of the electrode assembly 10" according to another embodiment, one or more separation membranes 300" are continuously supplied and can be folded in a zigzag pattern multiple times, and a first electrode plate assembly 100" or a second electrode plate 200" is placed in each folded portion to form the electrode assembly 10".

[0090] In this case, the first electrode plate assembly 100" faces one side of the zigzag-shaped separation membrane 300", and the second electrode plate 200 faces the opposite side of the separation membrane 300", so that the first electrode plate assembly 100" and the second electrode plate 200 are stacked on top of each other with the separation membrane 300" in between, without touching each other.

[0091] When the separation membrane 300" has such a zigzag structure, the portion where the first electrode plate 110 and the second electrode plate 200 may come into contact with each other due to the contraction of the separation membrane 300" may correspond to the edge of the separation membrane 300" in the width direction (for example, the Y-axis direction in Figure 6). For example, referring to Figure 6, when the separation membrane 300" is formed continuously and contracts, the region adjacent to the edge of the first electrode plate 110 where the electrode tab 112 protrudes and the opposite edge may come into contact with the second electrode plate 200, but the remaining edge region may have a somewhat lower probability of being exposed to the second electrode plate 200.

[0092] In this case, unlike in Figures 1 to 5, the insulating member 120" can be arranged only on some of the four edges of the first electrode plate 110, and the intended purpose can still be fully achieved. That is, the insulating member 120" can be concentrated on the portion of the first electrode plate 110 that is likely to be exposed to the second electrode plate 200 due to the contraction of the separation membrane 300". For example, referring to Figures 6 and 7, in the first electrode plate assembly 100, the first insulating member 120a and the second insulating member 120b can be arranged on the first electrode plate 110 along two opposite edges and spaced apart in the width direction of the separation membrane 300".

[0093] In the embodiments described in Figures 6 and 7, other features, except for the shape of the separation membrane 300" and the position of the insulating member 120", may be the same as those of the battery cell 1 described in Figures 1 to 5. For example, as shown in Figure 7, the insulating member 120" may have a loop-shaped structure so as to be able to cover both sides near one edge of the first electrode plate 110, and the portion in contact with the first electrode plate 110 may consist of a non-adhesive surface NA.

[0094] Referring to Figure 8, it can be confirmed that the stability of the battery cell 1 according to the embodiment is improved compared to a conventional battery cell by arranging the aforementioned insulating members 120, 120', and 120''.

[0095] Figure 8 is a graph showing the temperature changes of the electrode assemblies according to the embodiment and the electrode assemblies according to the first comparative example when they are heated.

[0096] Graph 8(b) shows the temperature change of the electrode assembly 10 during a test process in which the electrode assembly 10 according to the embodiment described in Figures 2 to 4 is heated inside a hot box.

[0097] Graph (a) in Figure 8 shows the temperature change of the electrode assembly according to the first comparative example during a test process in which the electrode assembly is heated inside a hot box. The electrode assembly according to the first comparative example is the electrode assembly 10 according to the embodiment described in Figures 2 to 4, in which the insulating member 120 is omitted. That is, the electrode assembly according to the first comparative example has a structure in which a plurality of first electrode plates 110 to which the insulating member 120 is not applied are alternately stacked with a plurality of second electrode plates 200 with a separation membrane 300 in between.

[0098] In both graphs, the heating test conditions for the hot box are identical. Specifically, the heating test is performed by sequentially carrying out the following steps: the first stage, raising the temperature around the electrode assembly placed inside the hot box to 130°C at a rate of 5°C / min; the second stage, maintaining the temperature around the electrode assembly at 130°C for 30 minutes; and the third stage, raising the temperature around the electrode assembly to 250°C at a rate of 5°C / min.

[0099] First, referring to graph (a), the electrode assembly of the first comparative example experienced a rapid temperature increase and the generation of flames the moment its temperature reached approximately 130°C. This is because, as explained through Figures 1 to 7, as the temperature of the battery cell increased, a shrinkage phenomenon of the separator membrane occurred around 130°C, causing the first electrode plate and the second electrode plate to come into contact with each other and short-circuit beyond the edge of the separator membrane.

[0100] On the other hand, referring to graph (b), it can be confirmed that the electrode assembly 10 according to the embodiment maintains a stable state even when heated to around 130°C. This is because, even if the separation membrane 300 shrinks at around 130°C, the insulating member 120 prevents the first electrode plate 110 and the second electrode plate 200 from coming into direct contact, thereby preventing a short circuit from occurring.

[0101] In other words, as shown in the test results in Figure 8, it can be confirmed that the electrode assemblies 10, 10”, to which the insulating members 120, 120', and 120'' according to the embodiment are applied, can prevent short circuits between the electrode plates due to the contraction of the separator membranes 300', 300'' even when their temperature rises to 130°C or higher. This significantly reduces the probability of thermal runaway occurring in the battery cell 1.

[0102] Figure 9 is a graph showing the test results of the capacity performance of a battery cell including the electrode assembly according to the embodiment and a battery cell including the electrode assembly according to the second comparative example.

[0103] In the graph of Figure 9, P1 represents the test result value of the capacity performance of a battery cell including the electrode assembly 10 according to the embodiment described in Figures 2 to 4, and P2 represents the test result value of the capacity performance of a battery cell including the electrode assembly according to the second comparative example.

[0104] Here, the electrode assembly according to the second comparative example is the electrode assembly 10 according to the embodiment described in Figures 2 to 4, in which the insulating member is changed to adhesive insulating tape. That is, in the electrode assembly according to the second comparative example, insulating tape coated with a bonding substance is attached to the mask portion of the plurality of first electrode plates.

[0105] At points P1 and P2 on the graph, two curves are shown for each point. The curve with an increasing voltage value represents the charging result, while the curve with a decreasing voltage value represents the discharging result.

[0106] As can be seen from the graph, the battery cell including the electrode assembly 10 according to the embodiment in which an insulating member composed of a non-adhesive surface is used to form a mask portion has a charge / discharge capacity that is increased by approximately 129% compared to the battery cell including the electrode assembly according to the second comparative example in which adhesive insulating tape is applied.

[0107] This is because, in the electrode assembly 10 of the embodiment, the battery reaction is smoothly carried out up to the area of ​​the mask portion that is in contact with the non-adhesive surface, whereas in the electrode assembly of the second comparative example, the battery reaction is hindered in the area of ​​the mask portion by the adhesive material of the insulating tape.

[0108] These test results confirm that the electrode assembly to which the insulating member according to the embodiment is applied exhibits significantly superior battery cell capacity performance compared to an electrode assembly to which existing adhesive insulating tape is applied.

[0109] Figure 10 is a graph showing the temperature changes of the electrode assemblies according to the embodiment and the electrode assemblies according to the second comparative example when they are heated.

[0110] In the graph of Figure 10, P1 shows the temperature change of the electrode assembly 10 during the test process in which the electrode assembly 10 according to the embodiment described in Figures 2 to 4 is heated inside a hot box. P2 shows the temperature change of the electrode assembly during the test process in which the electrode assembly according to the second comparative example applied to the test in Figure 9 is heated inside a hot box.

[0111] In the graph of Figure 10, the heating test conditions for the hot box are the same as those described in Figure 8.

[0112] By referring to the P1 and P2 values, it can be confirmed that the electrode assemblies according to the embodiment and the second comparative example maintain a stable state even when heated to around 130°C. This confirms that the short-circuit prevention effect of the insulating member with a non-adhesive surface is the same as the short-circuit prevention effect of existing adhesive insulating tape.

[0113] In other words, referring to the test results shown in Figures 9 and 10, it can be confirmed that the electrode assemblies 10' and 10'' to which the insulating members 120, 120' and 120'' according to the embodiment are applied are significantly more advantageous in terms of the capacity of the battery cell 1 compared to those in which the mask portion is formed with existing adhesive insulating tape, while maintaining the same short-circuit prevention effect between the electrode plates.

[0114] In particular, the insulating members 120, 120', and 120'' according to the embodiment do not hinder the lithium metal from participating in the battery reaction when the electrode plates constituting the electrode assemblies 10', 10'' are made of lithium metal, and prevent a decrease in the capacity of the battery cell 1 due to the formation of the mask portion 111a. Furthermore, since the inner surfaces of the insulating members 120, 120', and 120'' are composed of non-adhesive surfaces NA, the insulating members 120, 120', and 120'' can be chemically and physically stably arranged on the highly reactive lithium metal electrode plates.

[0115] On the other hand, the battery cell 1 according to this embodiment can be used as a power source for a variety of electronic devices, which may include, but are not limited to, laptop computers, netbooks, tablet PCs, mobile phones, MP3 players, wearable electronic devices, power tools, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric bicycles (E-bikes), electric scooters (E-scooters), electric golf carts, or energy storage systems (ESSs).

[0116] Although various embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to a person with average skill in the art that various modifications and variations are possible without departing from the technical idea of ​​the present invention as described in the claims. Furthermore, some components may be omitted in the embodiments described above, and each embodiment may be combined with one another. [Explanation of Symbols]

[0117] 1: Battery cell 10: Electrode assembly 20: Lead Tab 30: Case 100: 1st plate assembly 110: 1st plate 111: Plate body section 111a: Mask section 111b:Exposed part 112: First electrode tab 120, 120', 120”: Insulating material NA: Non-adhesive surface 200: 2nd pole plate 210: Second electrode tab 300, 300”: Separation membrane

Claims

1. One or more first electrode plates, One or more second plates having the opposite polarity to the one or more first plates, One or more separation membranes disposed between the one or more first electrode plates and the one or more second electrode plates, The comprising one or more insulating members placed on the one or more first electrode plates, A battery cell in which the one or more insulating members include non-adhesive surfaces that contact the one or more first electrode plates.

2. The battery cell according to claim 1, wherein at least a portion of one or more first electrode plates is made of lithium or a lithium-containing alloy.

3. The battery cell according to claim 2, wherein the non-adhesive surfaces of one or more insulating members are in contact with a portion of one or more first electrode plates made of lithium or a lithium-containing alloy.

4. The battery cell according to claim 1, wherein in the one or more insulating members, all portions that come into contact with the one or more first electrode plates are made of the non-adhesive surface.

5. The battery cell according to claim 1, wherein the insulating member comprises at least one of polyimide, polypropylene, polyvinyl chloride, polyester, polyacetal, polyolefin, and polyethylene.

6. The one or more first electrode plates are, One or more mask portions on which the one or more insulating members are placed, The separation membrane includes an exposed portion, The battery cell according to claim 1, wherein the one or more mask portions are formed along at least one edge of the one or more first electrode plates.

7. The one or more insulating members are The battery cell according to claim 6, having a loop-shaped structure in which a first insulating portion facing one surface of one or more first electrode plates and a second insulating portion facing the opposite surface of the first plate are continuously connected at both ends in the longitudinal direction.

8. The one or more insulating members are A first insulating member is arranged along the first edge portion from which the electrode tab protrudes from the first electrode plate, The battery cell according to claim 6, further comprising a second insulating member disposed along the second edge opposite the first edge of the first electrode plate.

9. The one or more insulating members are The first electrode plate further includes a third insulating member and a fourth insulating member, which are arranged along the third and fourth edges connected to the first and second edges, respectively. The battery cell according to claim 8, wherein one end of each of the first to fourth insulating members covers a portion of another insulating member adjacent to the one end, and the opposite end of each of the first to fourth insulating members is covered by another insulating member adjacent to the opposite end.

10. The battery cell according to claim 6, characterized in that, in the one or more insulating members, no adhesive substance is applied to the portion that comes into contact with the one or more mask portions.

11. The one or more insulating members are A fifth insulating member facing one surface of one or more of the first electrode plates, A sixth insulating member facing the opposite side of one of the first plates, The battery cell according to claim 6, wherein the fifth insulating member and the sixth insulating member are separated from each other.

12. The battery cell according to claim 11, wherein the fifth insulating member and the sixth insulating member have a frame-like structure surrounding the exposed portion.

13. The first electrode plate and the second electrode plate are arranged so as to face one side of the zigzag-folded separation membrane and the opposite side of the first side. The one or more insulating members are The battery cell according to claim 1, comprising a first insulating member and a second insulating member, each arranged along two edges of the first electrode plate and spaced apart from each other in the width direction of the separator membrane.

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