Electrode assembly and secondary battery including same

Abstract

The present invention relates to an electrode assembly including: an electrode laminate in which electrodes and separators are alternately interposed; and electrode leads extending from the electrodes, wherein the thickness of the electrode laminate is 15 times or more the thickness of the electrode leads so as to prevent or suppress heat propagation to an adjacent second battery.

Description

Electrode assembly and secondary battery including the same

[0001] [Related Application]

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0187656, filed with the Korean Intellectual Property Office on December 20, 2023, the contents of which are incorporated herein by reference in their entirety, and Korean Patent Application No. 10-2024-0133868, filed with the Korean Intellectual Property Office on October 2, 2024, the contents of which are incorporated herein by reference in their entirety.

[0003] [Technical Field]

[0004] The present invention relates to an electrode assembly and a secondary battery.

[0005] With the technological development and increasing demand for electric vehicles, mobile devices, and other devices, the demand for secondary batteries as an energy source is increasing. Unlike primary batteries, secondary batteries can be recharged and reused after a single use. A secondary battery consists of a cathode and anode. When a metal in the cathode oxidizes, electricity is generated through the movement of electrons released from the metal.

[0006] In an embodiment of the present invention, an electrode assembly is provided in which thermal runaway is prevented or suppressed.

[0007] In addition, an embodiment of the present invention provides a secondary battery that prevents or suppresses thermal runaway of an adjacent secondary battery.

[0008] An electrode assembly according to one embodiment of the present invention includes an electrode laminate in which electrodes and separators are alternately interposed and an electrode lead extending from the electrode, and the thickness of the electrode laminate is about 15 times or more the thickness of the electrode lead so as to prevent or suppress heat transmission to another adjacent secondary battery.

[0009] The electrode lead may be a positive lead.

[0010] The electrode lead is an anode lead, and the thickness of the electrode laminate may be about 22 times or more the thickness of the anode lead.

[0011] The electrode lead is an anode lead, and the thickness of the electrode laminate may be about 70 times or more the thickness of the anode lead.

[0012] The electrode lead is a negative lead, and the thickness of the electrode laminate may be about 30 times or more the thickness of the negative lead.

[0013] The electrode lead is a negative lead, and the thickness of the electrode laminate may be about 45 times or more the thickness of the negative lead.

[0014] The electrode lead is a negative lead, and the thickness of the electrode laminate can be about 140 times or more the thickness of the negative lead.

[0015] The thickness of the electrode laminate may be approximately 14 mm or more.

[0016] The thickness of the electrode laminate may be approximately 20 mm or more.

[0017] The thickness of the electrode laminate may be approximately 28 mm or more.

[0018] The battery case further includes a battery case configured to accommodate an electrode stack, the battery case includes a receiving portion having a shape corresponding to the electrode stack, and the depth of the receiving portion may be about 7.5 times or more the thickness of the electrode lead.

[0019] The receptacles are provided in pairs so as to be positioned on opposite sides of the electrode stack, and the sum of the depths of the pair of receptacles may be approximately 28 mm or more.

[0020] The thickness may be approximately 0.28 times the overall length.

[0021] The thickness may be approximately 0.09 times the full width or more.

[0022] The electrode stack is provided in multiple numbers, and the multiple electrode stacks can be arranged in the thickness direction.

[0023] A secondary battery according to one embodiment of the present invention includes an electrode stack including a plurality of electrodes and a plurality of separators alternately stacked with the plurality of electrodes, and a battery case accommodating the electrode stack, wherein the electrode stack includes 134 or fewer of the electrodes to prevent or suppress heat transmission to another adjacent secondary battery.

[0024] The electrode stack may include 67 or more of the above electrodes.

[0025] The electrode stack may have a thickness of about 28 mm or less.

[0026] The thickness of the electrode laminate may be approximately 14 mm or more.

[0027] A secondary battery according to one embodiment of the present invention includes a battery case including an electrode laminate, a receiving portion in which a concave space is formed to receive the electrode laminate, and a side portion extending from the receiving portion, wherein the receiving portion is formed by stretching by pressing and is configured to have a depth of about 14 mm or less, which is a maximum stretching degree.

[0028] The secondary battery according to the present invention can prevent or suppress the occurrence of thermal runaway by having an electrode laminate having a thickness greater than a predetermined thickness.

[0029] The secondary battery according to the present invention has an electrode laminate having a thickness greater than a predetermined thickness, thereby reducing heat transferred to adjacent secondary batteries, and thus preventing or suppressing thermal runaway of adjacent secondary batteries.

[0030] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0031] The following drawings attached to this specification illustrate embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0032] FIG. 1 is an assembly diagram illustrating a secondary battery according to a first embodiment of the present invention.

[0033] Figure 2 is a perspective view showing the secondary battery illustrated in Figure 1 assembled and completed.

[0034] Figure 3 is a cross-sectional view showing the secondary battery illustrated in Figure 2.

[0035] Figure 4a is a photograph taken when the depth of the receiving portion is 14 mm. Figure 4b is a photograph taken when the depth of the receiving portion exceeds 14 mm.

[0036] Figure 5 is a graph showing thermal energy over time when a heat source is placed on one side of a secondary battery according to a comparative example.

[0037] FIG. 6 is a graph illustrating thermal energy when a heat source is placed on one side of a secondary battery according to the first embodiment of the present invention.

[0038] Figure 7 is a graph summarizing the results of an experiment conducted to determine the effectiveness of a secondary battery according to the first embodiment of the present invention.

[0039] Figure 8 is a graph showing the time taken for the voltage to drop by varying the thickness of the secondary battery for the experiment illustrated in Figure 6 or Figure 7.

[0040] FIG. 9 is an exploded view illustrating a battery module including the secondary battery illustrated in FIG. 2.

[0041] Fig. 10 is a cross-sectional view illustrating a secondary battery according to a second embodiment of the present invention.

[0042] Fig. 11 is a cross-sectional view illustrating a secondary battery according to a third embodiment of the present invention.

[0043] Fig. 12 is a cross-sectional view illustrating a secondary battery according to a fourth embodiment of the present invention.

[0044] Fig. 13 is a cross-sectional view illustrating a secondary battery according to a fifth embodiment of the present invention.

[0045] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following embodiments.

[0046] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0047] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0048] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to encompass various modifications, equivalents, or alternatives of the embodiments.

[0049] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0050] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0051] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0052] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0053] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0054] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0055] The terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0056] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0057] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0058] Meanwhile, the terms “upper and lower directions,” “lower side,” and “front and rear directions” used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0059] As used herein, the terms “about,” “approximately,” and “substantially” are used to mean a range of or near that number or degree, taking into account inherent manufacturing and material tolerances.

[0060] To manufacture a secondary battery, a slurry of electrode active material is first applied to a positive electrode current collector and a negative electrode current collector to form a positive electrode and a negative electrode, which are then laminated on both sides of a separator to form an electrode assembly. The electrode assembly is then housed in a battery case, filled with electrolyte, and sealed.

[0061] Secondary batteries can experience thermal runaway due to side reactions and other factors. If thermal runaway occurs in a secondary battery, the battery will malfunction and will no longer be able to perform its intended function.

[0062] Secondary batteries may be provided in multiple units to form a battery module, or multiple battery modules or secondary batteries may be provided to form a battery pack. In this case, if a thermal runaway phenomenon occurs in one secondary battery, the thermal runaway phenomenon may spread to adjacent secondary batteries. In this case, a flame may occur due to the thermal runaway, and as a result, the flame may spread to a device equipped with a battery pack or the like, threatening the safety of users of the device. In consideration of such problems, the present invention provides, for example, an electrode assembly that prevents or suppresses the occurrence of thermal runaway.

[0063] Example 1

[0064] Fig. 1 is an assembly diagram illustrating a secondary battery (B) according to a first embodiment of the present invention. Fig. 2 is a perspective view illustrating the secondary battery (B) illustrated in Fig. 1 assembled and completed.

[0065] As shown in FIGS. 1 and 2, a secondary battery (B) configured to generate electricity can be provided.

[0066] The secondary battery (B) according to the present embodiment may include an electrode assembly (EA). The electrode assembly (EA) may be formed by alternately stacking electrodes (110) and separators (120). First, a slurry containing an electrode (110) active material, a binder, and a plasticizer may be applied to a positive electrode current collector (112) and a negative electrode current collector (112) to manufacture electrodes (110), such as a positive electrode and a negative electrode. Then, separators (120) may be stacked between the electrodes (110) to form an electrode assembly (EA), and the electrode assembly (EA) may be inserted into a battery case (200), and an electrolyte (140) may be injected and then sealed. (For example, see FIG. 3) According to one embodiment, the battery case (200) may be a pouch or a pouch type, and the battery case (200) may be formed from a pouch film.

[0067] An electrode assembly (EA) may include two types of electrodes (110), a positive electrode and a negative electrode, and a separator (120) interposed between the electrodes (110) to mutually insulate the electrodes (110). This electrode assembly (EA) may be provided in a stack type, a jellyroll type, a stack-and-fold type, etc., depending on how the positive electrode, the negative electrode, and the separator (120) are stacked. The two types of electrodes (110), i.e., the positive electrode and the negative electrode, may have a structure in which an active material slurry is applied to a current collector (112) of an electrode (110) in the form of a metal foil or metal mesh including aluminum and copper, respectively. The slurry may be typically formed by stirring a granular active material, an auxiliary conductor, a binder, a plasticizer, etc. in a state in which a solvent is added. The solvent of the slurry may be removed in a subsequent process.

[0068] The electrode tabs (113) are connected to the positive and negative electrodes of the electrode assembly (EA), respectively, and protrude outward from the electrode assembly (EA) to serve as a path for electrons to move between the inside and the outside of the electrode assembly (EA). The plurality of electrode tabs (113) may protrude in different directions of the electrode assembly (EA), as illustrated in FIG. 1, but are not limited thereto, and the plurality of electrode tabs (113) may protrude in parallel in the same direction or in various directions.

[0069] The electrode assembly (EA) may include an electrode lead (130) that is connected to an electrode tab (113) and supplies electricity to the outside of the secondary battery (B). The electrode lead (130) may be connected to the electrode tab (113) by spot welding, etc.

[0070] The electrode assembly (EA) may include an insulating portion (131) surrounding a portion of the electrode lead (130). The insulating portion (131) may be positioned to correspond to a position where the side portions (220) of the battery case (200) described below are fused. When the opposing side portions (220) are fused to each other, the insulating portion (131) may be positioned between the side portions (220) to adhere the electrode lead (130) to the pouch. In addition, the insulating portion (131) may prevent or suppress electricity generated from the electrode assembly (EA) from flowing to the pouch through the electrode lead (130) and maintain the sealing of the pouch. Therefore, the insulating portion (131) may be made of a non-conductive material that does not conduct electricity well. For example, the insulating portion (131) may be an insulating tape that is easy to attach to the electrode lead (130) and has a relatively thin thickness. However, without limitation thereto, various materials may be used as long as the electrode lead (130) can be insulated.

[0071] The electrode tab (113) configured to have a positive electrode may be referred to as a positive electrode tab (113a), the electrode tab (113) configured to have a negative electrode may be referred to as a negative electrode tab (113b), the electrode lead (130) configured to have a positive electrode may be referred to as a positive electrode lead (130a), and the electrode lead (130) configured to have a negative electrode may be referred to as a negative electrode lead (130b). The electrode lead (130) may have one end connected to the electrode tab (113) and the other end protruding toward the outside of the pouch. That is, the electrode lead (130) may include a positive lead (130a) having one end connected to the positive electrode tab (113a) and extending in the direction in which the positive electrode tab (113a) protrudes, and a negative electrode lead (130b) having one end connected to the negative electrode tab (113b) and extending in the direction in which the negative electrode tab (113b) protrudes. Meanwhile, both the positive electrode lead (130a) and the negative electrode lead (130b) can protrude outside the pouch at the other end. Accordingly, the positive electrode lead (130a) and the negative electrode lead (130b) can supply electricity generated inside the electrode assembly (EA) to the outside. In addition, the positive electrode tab (113a) and the negative electrode tab (113b) can each extend in various directions.

[0072] The positive electrode lead (130a) and the negative electrode lead (130b) may be made of different materials. The positive electrode lead (130a) may be made of the same aluminum material as the positive electrode collector (112), and the negative electrode lead (130b) may be made of the same copper material as the negative electrode collector (112) or a nickel-coated copper material. In addition, a portion of the electrode lead (130) protruding outside the pouch may serve as a terminal portion and be electrically connected to an external terminal.

[0073] The pouch can be manufactured from a highly flexible material to accommodate the electrode assembly (EA) therein. A flexible pouch film can be drawn and molded using a punch (not shown) or the like, such that a portion thereof is stretched to form a receiving portion (210) having a pocket-shaped electrode receiving space (210S), thereby manufacturing the pouch. The pouch can accommodate and seal the electrode assembly (EA) such that a portion of the electrode lead (130) is exposed.

[0074] The pouch film may include multiple layers. The pouch film may include a sealant layer and a barrier layer positioned outside the sealant layer. In one embodiment, the pouch film may include a surface protection layer positioned outside the barrier layer. In this case, the sealant layer may have a polymer material such as polypropylene, the barrier layer may have a metal material such as aluminum, and the surface protection layer may have a polymer material such as nylon.

[0075] When forming a receiving portion (210) on a pouch film, only one receiving portion (210) may be formed on one pouch film, but the present invention is not limited thereto, and two receiving portions (210) may be drawn and formed adjacent to each other on one pouch film. Then, two receiving portions (210) that are adjacent to each other may be formed. Each receiving portion (210) may have the same depth, but the present invention is not limited thereto, and the depths of each receiving portion (210) may be different from each other. After accommodating an electrode assembly (EA) in one receiving portion (210), the pouch may be folded around an axis so that another receiving portion (210) faces the receiving portion (210) in which the electrode assembly (EA) is accommodated. Accordingly, another receiving portion (210) may accommodate the electrode assembly (EA) from above. Since two receiving portions (210) accommodate one electrode assembly (EA), an electrode assembly (EA) having a thicker thickness can be accommodated than when there is only one receiving portion (210). In addition, since the pouch is folded, each side portion (220) is integrally connected to form a folding portion (230), so that when performing a sealing process later, the number of sides to be sealed can be reduced. Accordingly, the process speed can be improved and the number of sealing processes can be reduced.

[0076] The side portion (220) may include a lead sealing portion (222) configured to be positioned corresponding to the electrode lead (130) and a degas sealing portion (221) connected to the lead sealing portion (222). First, the lead sealing portion (222) may be sealed by fusing. Thereafter, the electrolyte (140) may be injected into the electrode receiving space (210S) through the degas sealing portion (221) that is not yet sealed, and the degas sealing portion (221) may be sealed by fusing. Thereafter, an activation process is performed, and when the gas generated through the activation process moves to the inside of the degas sealing portion (221), the remaining gas is removed by forming a hole, and the degas sealing portion (221) located closer to the receiving portion (210) than the portion where the hole is formed is sealed again, and then a trimming process can be performed to cut unnecessary portions so that the degas sealing portion (221) has a predetermined width. Thereafter, the degas sealing portion (221) can be folded to reduce the width.

[0077] Figure 3 is a cross-sectional view showing the secondary battery (B) shown in Figure 2 cut away.

[0078] Referring to FIG. 3, the secondary battery (B) may include an electrode stack (100) in which electrodes (110) and separators (120) are alternately interposed. A plurality of electrodes (110) and a plurality of separators (120) may be stacked in a vertical direction based on FIG. 3. As mentioned above, the electrode (110) may include a current collector (112) and an active material layer (111) applied on the current collector (112). The secondary battery (B) may include an electrode lead (130) extending from the electrode (110). The electrode lead (130) may have a material with excellent conductivity so as to transmit electricity generated in the electrode (110) to the outside of the secondary battery (B).

[0079] At this time, the electrode laminate (100) may be thickly formed. The situation in which the secondary battery (B) experiences thermal runaway may occur when an unintentional side reaction occurs inside the secondary battery (B), but if heat exceeding a predetermined value is introduced, the secondary battery (B) may experience thermal runaway. When thermal runaway occurs, the secondary battery (B) generates heat and a side reaction occurs, and if the degree becomes severe, a fire may occur.

[0080] When the electrode laminate (100) is formed thinly, less heat may be required for thermal runaway to occur in the secondary battery (B). When the electrode laminate (100) is formed thickly, more heat may be required for thermal runaway to occur in the secondary battery (B), and thus thermal runaway in the secondary battery (B) may be prevented or suppressed to some extent.

[0081] In order to prevent or suppress thermal runaway of a secondary battery (B), or even if thermal runaway occurs in a secondary battery (B), to prevent or suppress the spread of thermal runaway to adjacent secondary batteries (B), attempts have been made to add separate components at the battery module (BM) level. If a configuration is adopted to prevent or suppress such thermal runaway at the secondary battery (B) level, the use of separate components to prevent or suppress thermal runaway is eliminated, thereby saving the production cost for adding separate components and the material cost consumed when adding separate components.

[0082] The thickness of the conventional secondary battery (B) was approximately 9 mm.

[0083] The thickness (H1) of the electrode laminate (100) according to the first embodiment of the present invention may be about 14 mm or more. Alternatively, the thickness (H1) of the electrode laminate (100) may be about 20 mm or more. Alternatively, the thickness (H1) of the electrode laminate (100) may be about 28 mm. However, the thickness of the electrode laminate (100) may be limited by the depth of the receiving portion (210) included in the battery case (200). The receiving portion (210) may be formed by pressing a pouch, which is a raw material of the battery case (200). At this time, when pressing the pouch, the pouch may become thinner and form the receiving portion (210). That is, the pouch may stretch and form the receiving portion (210). At this time, the pouch may not stretch indefinitely, but may stretch with a predetermined elongation limit.

[0084] Fig. 4a is a photograph taken when the depth of the receiving portion (210) is about 14 mm. Fig. 4b is a photograph taken when the depth of the receiving portion (210) exceeds about 14 mm.

[0085] The predetermined limit of elongation can be set corresponding to a receiving portion depth of 14 mm per pouch. As shown in the photograph in Fig. 4a, when the receiving portion (210) depth is approximately 14 mm, it can be seen that no cracks occur in the pouch. However, as shown in the photograph in Fig. 4b, when the receiving portion (210) depth exceeds approximately 14 mm, cracks may occur in the pouch.

[0086] Since the experimental data related to thickness and temperature are shown in Fig. 7, let us examine the experimental data in the description part related to Fig. 7.

[0087] The electrode lead (130) can act as a passage through which electricity is discharged to the outside. If the electrode lead (130) is thick, the resistance decreases, so it may be preferable for the electrode lead (130) to have a certain thickness (H2) or more. However, if the electrode lead (130) is too thick, a problem of poor deformation may occur. When the secondary battery (B) is provided in the form of a battery module (BM), the electrode lead (130) may be in contact with a bus bar (920) (for example, see FIG. 9), and the electrode lead (130) may need to be bent in the process of being in contact with the bus bar (920). Therefore, the electrode lead (130) may require an appropriate thickness (H2) value.

[0088] The reason why the electrode lead (130) is used as one of the standards for the thickness of the secondary battery (B) or the electrode laminate (100) may be because the electrode lead (130) may be made of a material having strong rigidity, making it easy to measure the thickness. In addition, the electrode lead (130) may be easy to measure the thickness because it protrudes outside the secondary battery.

[0089] At this time, the electrode lead (130) may include a positive electrode lead (130a) and a negative electrode lead (130b), as previously discussed. The positive electrode lead (130a) and the negative electrode lead (130b) may each have different materials. Accordingly, the appropriate thickness (H2) may vary depending on the material. The thickness of the positive electrode lead (130a) may be about 0.4 mm, and the thickness of the negative electrode lead (130b) may be about 0.2 mm. Alternatively, the thickness of the positive electrode lead (130a) may be about 0.6 mm, and the thickness of the negative electrode lead (130b) may be about 0.3 mm.

[0090] The thickness (H1) of the electrode laminate (100) may be about 15 times or more the thickness (H2) of the electrode lead (130) to prevent or suppress heat transfer to another adjacent secondary battery (B). At this time, the electrode lead (130) may be the positive electrode lead (130a). When the electrode laminate (100) has a thickness (H1) of about 9 mm and the positive electrode lead (130a) has a thickness (H2) of about 0.6 mm, the thickness (H1) of the electrode laminate (100) may be about 15 times the thickness (H2) of the positive electrode lead (130a). In order to have a thickness (H1) that is thicker than the thickness of a conventional electrode laminate (100), the electrode laminate (100) may have a thickness (H1) that exceeds about 15 times the thickness of the positive electrode lead (130a).

[0091] According to one embodiment, the thickness (H1) of the electrode stack (100) may be about 22 times or more the thickness (H2) of the positive electrode lead (130a). When the electrode stack (100) has a thickness (H1) of about 9 mm and the positive electrode lead (130a) has a thickness (H2) of about 0.4 mm, the thickness (H1) of the electrode stack (100) may be about 22 times that of the positive electrode lead (130a). In order to have a thickness (H1) that is thicker than that of a conventional electrode stack (100), the electrode stack (100) may have a thickness (H1) that exceeds about 22 times that of the positive electrode lead (130a).

[0092] According to one embodiment of the present invention, the thickness (H1) of the electrode laminate (100) may be about 70 times or more the thickness (H2) of the positive electrode lead (130a). When the electrode laminate (100) has a thickness (H1) of about 28 mm and the positive electrode lead (130a) has a relatively small thickness (H2) of about 0.4 mm, the thickness (H1) of the electrode laminate (100) may be about 70 times the thickness (H2) of the positive electrode lead (130a). As described below, since the effect when the thickness (H1) of the electrode laminate (100) is about 28 mm can be confirmed, the electrode laminate (100) may have a relatively thick thickness (H1).

[0093] In one embodiment, when the anode lead (130a) is about 0.6 mm, and the electrode stack (100) has a thickness (H1) of about 28 mm, the thickness (H1) of the electrode stack (100) may be approximately 46.7 times the thickness (H2) of the anode lead (130a). The thickness (H1) of the electrode stack (100) may be at least about 46.7 times the thickness (H2) of the anode lead (130a).

[0094] When the negative electrode lead (130b) is taken as a reference, the thickness (H1) of the electrode laminate (100) may be about 30 times or more the thickness (H2) of the negative electrode lead (130b). When the electrode laminate (100) has a thickness (H1) of about 9 mm and the negative electrode lead (130b) has a thickness (H2) of about 0.3 mm, the thickness (H1) of the electrode laminate (100) may be about 30 times the thickness (H2) of the negative electrode lead (130b). In order to have a thickness (H1) that is thicker than the thickness of a conventional electrode laminate (100), the electrode laminate (100) may have a thickness (H1) that exceeds about 30 times that of the negative electrode lead (130b).

[0095] According to one embodiment of the present invention, the thickness (H1) of the electrode laminate (100) may be about 45 times or more the thickness (H2) of the negative electrode lead (130b). When the electrode laminate (100) has a thickness (H1) of about 9 mm and the negative electrode lead (130b) has a thickness (H2) of about 0.2 mm, the thickness (H1) of the electrode laminate (100) may be about 45 times the thickness (H2) of the negative electrode lead (130b). In order to have a thickness (H1) that is thicker than the thickness of a conventional electrode laminate (100), the electrode laminate (100) may have a thickness (H1) that exceeds about 45 times the thickness of the negative electrode lead (130b).

[0096] According to one embodiment of the present invention, the thickness (H1) of the electrode laminate (100) may be about 140 times or more the thickness (H2) of the negative electrode lead (130b). When the electrode laminate (100) has a thickness (H1) of about 28 mm and the negative electrode lead (130b) has a relatively small thickness (H2) of about 0.2 mm, the thickness (H1) of the electrode laminate (100) may be about 140 times the thickness (H2) of the negative electrode lead (130b). As described below, since the effect when the thickness (H1) of the electrode laminate (100) is about 28 mm can be confirmed, the electrode laminate (100) may have a thickness (H1) thicker than this.

[0097] In one embodiment, when the negative lead (130b) is about 0.3 mm, and the electrode laminate (100) has a thickness (H1) of about 28 mm, the thickness (H1) of the electrode laminate (100) may be approximately 93.3 times the thickness (H2) of the negative lead (130b). The thickness (H1) of the electrode laminate (100) may be at least about 93.3 times the thickness (H2) of the negative lead (130b).

[0098] The ratio of the thickness (H1) of the electrode laminate (100) to the thickness (H2) of the electrode lead (130) discussed above was calculated through an example of what the thickness (H2) of the electrode lead (130) may have. However, the thickness (H2) of the electrode lead (130) that is the basis of the calculation is not limited to the thickness (H2) presented above, and it can be understood that the thickness (H1) of the electrode laminate (100) has a ratio to the thickness (H2) of the electrode lead (130).

[0099] Furthermore, the thickness (H1) of the electrode stack (100) may be a factor in explaining the thickness (D1) of the secondary battery (B). This is because the thickness of the electrode stack (100) contributes to the thickness of the secondary battery (B). Additionally, the thickness of the battery case (200) may be considered in calculating the thickness (D1) of the secondary battery (B). As described above, the secondary battery (B) may further include a battery case (200) configured to accommodate the electrode stack (100). Therefore, the description of the thickness described above may be understood as being replaced with a description of the thickness (D1) of the secondary battery (B) including the battery case (200). This is because, when the battery case (200) is formed of a pouch film, the thickness of the pouch film may be similar to the thickness (H2) of the electrode lead (130), and the thickness (H2) of the electrode lead (130) may be very thin compared to the thickness (H1) of the electrode assembly (EA), so even if the thickness of the battery case (200) is added to the thickness (H1) of the electrode assembly (EA), there may not be a large difference.

[0100] As described above, the battery case (200) may include a receiving portion (210) having a shape corresponding to the electrode stack (100). As illustrated in FIG. 1, the two receiving portions are provided facing each other symmetrically in the vertical direction, and when information about the thickness (D1) of the secondary battery (B) is replaced with information about the receiving portion (210), according to one embodiment, the depth of the receiving portion (210) may be about 7.5 times or more the thickness (H2) of the electrode lead (130). In this case, the electrode lead (130) may be positioned at the center in the thickness direction with respect to the secondary battery (B). The fact that the depth of the receiving portion (210) is about 7.5 times or more can be calculated by taking into account the fact that the electrode stack (100) is at least about 15 times or more the electrode lead (130), the thickness (H1) of the electrode stack (100) can be considered as the thickness (D1) of the secondary battery (B) including the battery case (200), the fact that the receiving portions (210) can be provided as a pair symmetrically from top to bottom, and the fact that the influence of the thickness of the side portion (220) on the depth of the secondary battery (B) is minimal. Therefore, taking these points into account, the lower limit of the depth of the receiving portion (210) can be set by taking into account the case where the electrode lead (130) is the positive lead (130a) and the case where the negative lead (130b). When the electrode lead (130) is the positive lead (130a), the depth of the receiving portion (210) may be about 7.5 times, about 11 times, or about 35 times or more the thickness (H2) of the positive lead (130a). Furthermore, the depth of the receiving portion may be about 15 times, about 22.5 times, or about 70 times or more the thickness (H2) of the negative lead (130b).

[0101] As previously described, the receiving portions (210) may be provided in pairs so as to be positioned on opposite sides of the electrode stack (100). The sum of the depths of the pair of receiving portions (210) may be approximately 28 mm or more. This merely represents a numerical value according to one embodiment of the present invention, and as described above, in order to achieve the effects of the present invention, the sum of the depths of the pair of receiving portions (210) may be approximately 14 mm or approximately 20 mm or more.

[0102] In the above description, the thickness (D1) of the secondary battery (B) was described using the thickness (H1) of the electrode laminate (100). According to one embodiment of the present invention, the thickness (D1) of the secondary battery (B) can be described based on the total length (D3) and / or total width (D2) of the secondary battery (B). The directions of the total length (D3) and total width (D2) can be referred to in FIG. 2.

[0103] Fig. 5 is a graph showing the change in thermal energy according to the distance when a heat source (HS) is placed on one side of a secondary battery (B-0) according to a comparative example. Fig. 6 is a graph showing the change in thermal energy according to the distance when a heat source (HS) is placed on one side of a secondary battery (B) according to the first embodiment of the present invention. As shown in Figs. 5 and 6, the thickness of the secondary battery (B) according to the first embodiment is thicker than the thickness of the secondary battery (B-0) according to the comparative example.

[0104] In Fig. 5, a plurality of secondary batteries (B-0) are arranged so as to be in contact with one direction. At this time, a heat source (HS) may be arranged so as to be in contact with one side of the plurality of secondary batteries (B-0). When a certain amount of heat is applied from the heat source (HS), the secondary battery (B-0) can have maximum thermal potential energy on the side in contact with the heat source (HS). As the secondary battery (B-0) moves away from the heat source (HS), the thermal potential energy may exhibit a decreasing trend.

[0105] In Fig. 6, a plurality of secondary batteries (B) according to the first embodiment are arranged so as to be in contact with one side of a heat source (HS). In Fig. 6, when a constant amount of heat is applied from the heat source (HS) as in Fig. 5, the thermal potential energy of the secondary batteries (B) may show a decreasing trend as they move away from the side in contact with the heat source (HS). However, unlike in Fig. 5, since the thickness of the secondary battery (B) according to the first embodiment is thicker than the thickness of the secondary battery (B-0) according to the comparative example, the amount of thermal energy (A2) that decreases as it passes through the secondary battery (B) in contact with the heat source (HS) is greater than the amount of thermal energy (A1) that decreases as it passes through the secondary battery (B-0) in contact with the heat source (HS). Therefore, the secondary battery (B) having a thick thickness transfers lower thermal energy to the adjacent secondary battery (B) than the secondary battery (B-0) having a thin thickness.

[0106] Figure 7 is a graph summarizing the results of an experiment conducted to determine the effect of the thickness of a secondary battery (B) according to the first embodiment of the present invention on heat transfer.

[0107] In the experiment that produced the results in Fig. 7, a secondary battery (B) with a thickness (D1) of 14 mm and a secondary battery (B) with a thickness (D1) of 28 mm were placed in contact with the same heat source (HS) on one side, and the temperature was measured on the opposite side. In both graphs, the part where the temperature rises rapidly can be considered the part where thermal runaway occurs.

[0108] Even though the thickness was different, the temperature increased by thermal runaway was approximately the same at 750℃.

[0109] However, the secondary battery (B) that is relatively thick at 28 mm took longer to cause thermal runaway than the secondary battery (B) that is relatively thin at 14 mm. This shows that the secondary battery (B) that is relatively thick requires more heat to cause thermal runaway than the secondary battery (B) that is relatively thin. This could mean that when multiple secondary batteries (B) are provided, the thicker the secondary battery (B) that triggers thermal runaway, the later the trigger explodes. On the other hand, since the thinner the secondary battery (B) is, the more heat is required for thermal runaway to occur, which shows that the stability against thermal runaway is lower.

[0110] Furthermore, when multiple secondary batteries (B) are provided, even if one secondary battery (B) experiences thermal runaway, it can be seen that the thermal runaway becomes difficult to spread because a relatively thick secondary battery (B) requires more heat for the adjacent secondary battery (B) to experience thermal runaway. Considering that the temperature rises to approximately 750°C as illustrated in Fig. 7 when one adjacent secondary battery (B) experiences thermal runaway, a secondary battery (B) that is relatively thin may relatively easily experience thermal runaway due to such heat, causing a chain reaction of thermal runaway, whereas a secondary battery (B) that is relatively thick may not experience thermal runaway even when the temperature of the adjacent secondary battery (B) rises to approximately 750°C because the relatively thick secondary battery (B) may not reach sufficient heat for thermal runaway.

[0111] Furthermore, as illustrated in Fig. 7, a secondary battery (B) having a relatively thick thickness may have a temperature before thermal runaway lower than a secondary battery (B) having a thin thickness. Therefore, even if thermal runaway does not occur, the temperature of the relatively thick secondary battery (B) increased by the heat reaction is lower, and thus the heat transferred to the adjacent secondary battery (B) may also be less. Therefore, when a secondary battery (B) having a relatively thick thickness is used, thermal runaway of the adjacent secondary battery (B) can be relatively more prevented or suppressed.

[0112] 8 is a graph showing the time taken for the voltage to drop by varying the thickness of the secondary battery (B) for the experiment illustrated in FIG. 6 or FIG. 7.

[0113] Referring to Fig. 8, the relationship between the increase in thickness of the secondary battery (B) and the speed of heat propagation is explained.

[0114] The x-axis of the graph illustrated in Fig. 8 corresponds to the thickness of the secondary battery (B). The y-axis of the graph illustrated in Fig. 8 corresponds to the time taken until the voltage drops. For example, the time taken for the voltage to drop, corresponding to the y-axis, indicates the time taken for the voltage to drop from 3.3 V, when the secondary battery (B) is considered fully charged, to 0.03 V. The secondary battery (B) may begin to deteriorate due to a heat source, causing a voltage drop. The time taken until the voltage at which the secondary battery (B) is considered completely deteriorated (for example, 0.03 V) was measured experimentally and is illustrated in Fig. 8. At this time, the fact that the voltage drop to 0.03 V, rather than the voltage drop to 0 V, was observed can be understood to mean that the voltage drop to 0.03 V, which is close to this, was observed because it is difficult for a voltage drop to 0 V to occur in reality.

[0115] As illustrated in Figure 8, as the thickness of the secondary battery (B) increases, the time for the voltage drop increases accordingly. In other words, the time for the secondary battery (B) to be damaged by a heat source increases as the secondary battery (B) becomes thicker. More precise times are as described in Table 1 below.

[0116] Secondary battery thickness (mm) Voltage drop time (sec) 2899526.580015.669314590

[0117] For Table 1 above, an analysis similar to Table 2 below can be conducted. The following ratios are rounded to the third decimal place.

[0118] Secondary battery thickness (mm)Difference from minimum value (mm)Relative ratio between differencesVoltage drop time (sec)Difference from minimum value (sec)Relative ratio between differences28148.759954053.9326.512.57.818002102.0415.61.616931031140N / A5900N / A

[0119]

[0120] When analyzing the trend of voltage drop time according to the thickness of the secondary battery (B), it is difficult to assume that the secondary battery is 0 mm, so it is difficult to simply view the voltage drop time as having increased by less than 2 times, from 590 seconds to 995 seconds, even though it has doubled from 14 mm to 28 mm. To eliminate the influence of the initial value, an analysis by difference was conducted.

[0121] In Table 2 above, the column to the right of the thickness of the secondary battery (B) shows the difference from the minimum value of the thickness of the secondary battery (B) and the relative ratio between the differences. In Table 2 above, the column to the right of the voltage drop time shows the difference from the minimum value of the voltage drop time and the relative ratio between the differences. For example, the relative ratio between the differences from the minimum value of the thickness of the secondary battery (B) means the ratio of the difference value from the minimum value in that row to the difference value (1.6) from the smallest minimum value. The relative ratio between the differences from the minimum value of the voltage drop time can also be obtained in the same way as the relative ratio between the differences from the minimum value of the thickness of the secondary battery (B).

[0122] At this time, for example, when examining the row for the secondary battery (B) with a thickness of 28 mm, the ratio for the difference in voltage drop time is 3.93 times, while the ratio for the difference in the thickness of the secondary battery (B) is 8.75 times. Through this, it can be seen that the increase rate of the voltage drop time is smaller than the increase rate of the thickness of the secondary battery (B). In other words, it can be seen that the ratio for the time for the secondary battery's function to decline due to heat is less than the rate at which the thickness increases.

[0123] Furthermore, the number of electrodes according to the thickness of the secondary battery (B) used in the above experiment was measured as follows. Table 3 below divides the electrodes into positive and negative electrodes and lists the number of each.

[0124] Secondary battery thickness (mm) Positive electrode (ea) Negative electrode (ea) 28666826.5636415.63738143334

[0125]

[0126] Referring to Table 3 above, it can be seen that as the thickness of the secondary battery (B) increases, the number of positive and negative electrodes increases. The increase in thickness of the secondary battery (B) does not simply mean that the thickness is increased, but also means that the number of electrodes (110) increases, which may mean that the secondary battery (B) can produce more electricity overall. In other words, the increase in thickness of the secondary battery (B) is advantageous in that it not only slows down heat propagation but also produces more electricity. In the above, considering that the thickness of the secondary battery (B) increases to 28 mm, the electrode stack (100) included in the secondary battery (B) may be provided with a total of 134 electrodes or less. Furthermore, when the thickness of the secondary battery (B) is 14 mm or more, heat propagation can be slowed down compared to existing secondary batteries, and therefore the electrode stack (100) may be provided with a total of 67 electrodes or more.

[0127] Furthermore, as examined in the table above, the thickness of the secondary battery (B) was set to a maximum of 28 mm and the experiment was conducted. This may be because, when the receiving portion (210) of the battery case (200) is formed by stretching using a press, the maximum stretching degree of 14 mm is the limit of the depth that can be formed by stretching.

[0128] FIG. 9 is an exploded view showing a battery module (BM) including the secondary battery (B) illustrated in FIG. 2.

[0129] Secondary batteries (B) may be provided in multiples to form a battery module (BM). That is, the battery module (BM) may include secondary batteries (B).

[0130] A battery module (BM) may include a module case (910) configured to accommodate at least one secondary battery (B). The secondary batteries (B) may be provided in multiple numbers and stacked in one direction. The module case (910) may have a shape that corresponds to the shapes of the multiple secondary batteries (B).

[0131] The module case (910) may include a module case body (911) that forms a battery accommodation space (910S) capable of accommodating a plurality of secondary batteries (B). The module case body (911) may have a “U” shape in cross-section and may have an opening formed therein that communicates with the battery accommodation space (910S). The module case (910) may include a module case cover (912) that covers at least one of the openings formed in the module case body (911). For example, the module case body (911) may be configured to cover the lower surface, left and right sides of the battery accommodation space (910S), and the module case cover (912) may be configured to have a plate shape that covers the upper surface of the battery accommodation space (910S). The module case (910) may include an end plate (913) that covers the front and rear sides of the battery accommodation space (910S).

[0132] A busbar frame (921) may be provided to be accommodated in the battery accommodation space (910S) and adjacent to the end plate (913). A busbar (920) may be mounted on the busbar frame (921). In the secondary battery (B) described above, electricity formed in the electrode (110) may move toward the electrode lead (130) through the electrode tab (113). In order to control the electricity emitted from each electrode lead (130) of a plurality of secondary batteries (B), the end of each electrode lead (130) may be in contact with the busbar (920). A plurality of busbars (920) may be provided to correspond to each of the electrode leads (130). The busbar (920) may be, for example, a metal plate having a plate shape. The thickness of the electrode lead (130) may be thinner than that of the busbar (920). When the electrode lead (130) comes into contact with the bus bar (920) and electricity transferred through the electrode lead (130) flows through the bus bar (920), a component requiring electricity can be supplied with electricity by coming into contact with the bus bar (920). Since the bus bar (920) may have a thickness thicker than the electrode lead (130), an electrical connection can be implemented more easily than when electricity is directly connected to the electrode lead (130). The bus bar (920) may be mounted and fixed to the bus bar frame (921). The bus bar (920) may be coupled to the bus bar frame (921) by a force-fit. However, the present invention is not limited thereto, and it is considered that the idea of ​​the present invention can be applied to a case where the bus bar (920) is coupled to the bus bar frame (921) by a fastening member or by an adhesive. Some of the plurality of bus bars (920) may be configured to be exposed to the outside of the end plate (913) described later so that a configuration requiring electricity can be easily connected to the bus bars (920).

[0133] A battery module (BM) may include a plurality of secondary batteries (B), and the plurality of secondary batteries (B) may have different voltages during operation. The plurality of secondary batteries (B) must have the same voltage so that their respective charge states can be maintained identically, and the charging of the plurality of secondary batteries (B) can be performed identically. Therefore, it may be necessary to monitor the voltages of the plurality of secondary batteries (B).

[0134] To this end, the battery module (BM) may include a substrate (930) configured to be in contact with a bus bar (920) through which electricity flows of a plurality of secondary batteries (B), and a connector (930) may be mounted on the substrate (930), such that the connector (930) may be connected to a battery management system (BMS) configured to monitor the voltage of the secondary batteries (B). The BMS may be electrically connected to the connector (930), and information about the voltage received by the substrate (930) in contact with the bus bar (920) may be transmitted to the BMS through the connector (930) to receive information about the voltage of the secondary batteries (B). The BMS may control each of the plurality of secondary batteries (B) so that each of the plurality of secondary batteries (B) has a voltage within a preset range based on the voltage information about each of the plurality of secondary batteries (B).

[0135] Below, embodiments different from the first embodiment are described. Commonalities with the first embodiment will be omitted as much as possible, and the other embodiments will be described focusing on differences. In other words, it should be clear that any details not described in the other embodiments can be supplemented by the first embodiment.

[0136] Second Example

[0137] Fig. 10 is a cross-sectional view illustrating a secondary battery (B) according to a second embodiment of the present invention.

[0138] The second embodiment differs from the first embodiment in that a plurality of electrode laminates (100-1) are provided.

[0139] A plurality of electrode stacks (100-1) may be arranged in the thickness direction. As illustrated in FIG. 10, according to one embodiment, the plurality of electrode stacks (100-1) may be composed of a first electrode stack (100a-1) and a second electrode stack (100b-1), and each electrode stack (100-1) forms a bundle in which each electrode tab (113) is connected, and each bundle-shaped electrode tab (113) may be coupled to an electrode lead (130) through a separate member.

[0140] Third Example

[0141] Fig. 11 is a cross-sectional view illustrating a secondary battery (B) according to a third embodiment of the present invention.

[0142] The third embodiment differs from the first embodiment in that the thickness of the receiving portion (210-2) is different.

[0143] In order to prevent the propagation of thermal runaway to an adjacent secondary battery (B), the thickness (D1) of the secondary battery (B) can be increased by increasing the thickness (H1) of the electrode stack (100) as well as increasing the thickness of the receiving portion (210-2). This is because the thickness (D1) of the secondary battery (B) can be formed by the sum of the thickness (H1) of the electrode stack (100) and the thickness of the receiving portion (210-2).

[0144] In one embodiment, the thickness of the portion forming the bottom surface of the receiving portion (210-2) may be increased. For example, the thickness of the portion forming the bottom surface of the receiving portion (210-2) may be thicker than the thickness of the portion forming the perimeter of the receiving portion (210-2).

[0145] Example 4

[0146] Fig. 12 is a cross-sectional view illustrating a secondary battery (B) according to a fourth embodiment of the present invention.

[0147] The fourth embodiment differs from the first embodiment in that an insulating member (300-3) is further provided.

[0148] The secondary battery (B) may include an insulating member (300-3) positioned between the receiving portion (210) and the electrode stack (100). By providing the insulating member (300-3), the secondary battery (B) may have a thicker thickness (D1) than conventional batteries.

[0149] The insulating member (300-3) may have lower thermal conductivity than the electrode assembly (EA) and / or the battery case (200). Accordingly, the insulating member (300-3) may prevent or suppress thermal runaway propagation to an adjacent secondary battery (B).

[0150] Example 5

[0151] Fig. 13 is a cross-sectional view illustrating a secondary battery (B) according to the fifth embodiment of the present invention.

[0152] The fifth embodiment differs from the first embodiment in that an additional insulating member (300-5) is provided. The fifth embodiment differs from the fourth embodiment in that the position of the insulating member (300-5) is different.

[0153] The insulating member (300-5) may be positioned on the outside of the receiving portion (210). The insulating member (300-5) may contact the receiving portion (210) from the outside of the receiving portion (210). Accordingly, the insulating member (300-5) may increase the thickness (D1) of the secondary battery (B) and prevent or suppress thermal runaway propagation to an adjacent secondary battery (B).

[0154] Unless explicitly stated otherwise, the embodiments described above may be combined with other embodiments. Alternatively, combinations between embodiments may be considered possible, unless one embodiment is explicitly restricted from being combined with another embodiment. Combinations of one embodiment with another embodiment are deemed to be disclosed in this document.

[0155] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope of the technical concept of the present invention and the equivalent scope of the claims set forth below by those skilled in the art. Accordingly, the technical scope of the various embodiments of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims

1. An electrode laminate in which electrodes and separators are alternately arranged; and comprising an electrode lead extending from the above electrode; An electrode assembly wherein the thickness of the electrode laminate is at least 15 times the thickness of the electrode lead so as to prevent or suppress heat transfer to adjacent secondary batteries.

2. In paragraph 1, An electrode assembly wherein the above electrode lead is a positive electrode lead.

3. In paragraph 1, The above electrode lead is the positive lead, An electrode assembly wherein the thickness of the electrode laminate is about 22 times or more the thickness of the positive electrode lead.

4. In paragraph 1, The above electrode lead is the positive lead, An electrode assembly wherein the thickness of the electrode laminate is about 70 times or more the thickness of the positive electrode lead.

5. In paragraph 1, The above electrode lead is the negative lead, An electrode assembly wherein the thickness of the electrode laminate is about 30 times or more the thickness of the negative electrode lead.

6. In paragraph 1, The above electrode lead is the negative lead, An electrode assembly wherein the thickness of the electrode laminate is about 45 times or more the thickness of the negative electrode lead.

7. In paragraph 1, The above electrode lead is the negative lead, An electrode assembly wherein the thickness of the electrode laminate is about 140 times or more the thickness of the negative electrode lead.

8. In paragraph 1, An electrode assembly wherein the thickness of the electrode laminate is about 14 mm or more.

9. In paragraph 1, An electrode assembly wherein the thickness of the electrode laminate is about 20 mm or more.

10. In paragraph 1, An electrode assembly wherein the thickness of the electrode laminate is about 28 mm or more.

11. In paragraph 1, Further comprising a battery case configured to accommodate the electrode laminate, The above battery case includes a receiving portion having a shape corresponding to the electrode laminate, An electrode assembly wherein the depth of the receptacle is at least about 7.5 times the thickness of the electrode lead.

12. In paragraph 11, The above-mentioned receiving portions are provided in pairs so as to be located on opposite sides of the electrode stack, An electrode assembly wherein the sum of the depths of the pair of above-mentioned receptacles is approximately 28 mm or more.

13. In paragraph 1, An electrode assembly having a thickness of at least about 0.28 times the overall length.

14. In paragraph 1, An electrode assembly having a thickness of at least approximately 0.09 times the full width.

15. In paragraph 1, The above electrode laminates are provided in multiples, An electrode assembly in which a plurality of the above electrode laminates are arranged in the thickness direction.

16. An electrode laminate comprising a plurality of electrodes and a plurality of separators alternately laminated with the plurality of said electrodes; and A battery case comprising the electrode laminate, A secondary battery comprising 134 or fewer of the above electrodes, wherein the electrode stack prevents or suppresses heat transmission to adjacent secondary batteries.

17. In paragraph 16, The above electrode stack is a secondary battery including 67 or more of the above electrodes.

18. In paragraph 16, A secondary battery having the electrode laminate having a thickness of 28 mm or less.

19. In Article 16, A secondary battery wherein the thickness of the electrode laminate is 14 mm or more.

20. Electrode laminate; and A battery case including a receiving portion in which a concave space is formed to receive the electrode laminate and a side portion extending from the receiving portion, A secondary battery in which the above-mentioned receiving portion is formed by being stretched by a press and configured to have a depth of about 14 mm or less, which is the maximum degree of stretching.

21. In paragraph 1, An electrode assembly further comprising an insulating member.

22. In paragraph 21, An electrode assembly wherein the insulating member is positioned on the inner side of the receiving portion.

23. In paragraph 21, An electrode assembly wherein the insulating member is positioned on the outside of the receiving portion.

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