Battery cell and battery module comprising the same

Abstract

A battery cell according to one embodiment of the present application includes: a battery case having an electrode assembly mounted therein, and including a sealing portion whose outer periphery is sealed by heat melting; an electrode lead wire electrically connected to an electrode tab included in the electrode assembly, and protruding in an outer side direction of the battery case via the sealing portion; a lead wire film located between the electrode lead wire and the sealing portion; and a protection member in contact with at least a portion of an outer surface of the electrode lead wire, wherein a size of the protection member varies according to a temperature of the electrode lead wire.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0015510, filed with the Korean Intellectual Property Office on February 3, 2021, the contents of which are incorporated herein by reference in their entirety.

[0003] This disclosure relates to a battery cell and a battery module including the battery cell, and more specifically, to a battery cell with improved safety and a battery module including the battery cell. Background Technology

[0004] With technological advancements and increasing demand for mobile devices, the need for secondary batteries as an energy source is rapidly growing. In particular, secondary batteries are attracting significant attention as a power source for electrically powered devices such as electric bicycles, electric vehicles, and hybrid vehicles, as well as for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices.

[0005] Based on the shape of the battery casing, secondary batteries are classified into cylindrical batteries with electrode assemblies installed in cylindrical metal cans, prismatic batteries with electrode assemblies installed in prismatic metal cans, and pouch batteries with electrode assemblies installed in pouch-shaped casings formed of aluminum laminates. Here, the electrode assembly installed in the battery casing is a power generation device capable of charging and discharging, having a structure with a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The electrode assemblies are further classified into jelly roll type and stacked type. In the jelly roll type, the electrode assembly, including the separator between the positive and negative electrodes, is rolled up (each electrode assembly is made of a long sheet coated with an active material). In the stacked type, multiple positive electrodes and multiple negative electrodes are stacked in an order such that the separator is positioned between the positive and negative electrodes.

[0006] In particular, pouch batteries with stacked or stacked / folded electrode assemblies mounted in an aluminum laminated battery casing are increasingly used due to their low manufacturing cost, light weight, and ease of deformation.

[0007] Consequently, with the increasing demand for rechargeable batteries, the need to improve the capacity or energy density of rechargeable batteries is also increasing, and correspondingly, the demand for the safety of battery cells is also gradually increasing.

[0008] However, in the case of pouch cells, some battery cells may overheat due to overcurrent or other reasons, leading to thermal runaway and potential fire. Therefore, when a battery cell generates abnormal heat, it is necessary to develop a battery cell that can physically interrupt the current to the cell while ensuring user safety. Summary of the Invention

[0009] Technical issues

[0010] The purpose of this invention is to provide a battery cell with improved safety by providing a protective component on the electrode leads that can interrupt the current of the battery cell, and a battery module including the battery cell.

[0011] The purpose of this invention is not limited to the above-described purposes, and those skilled in the art should clearly understand other purposes not described herein through the following detailed description and accompanying drawings.

[0012] Technical solution

[0013] According to one aspect of this disclosure, a battery cell is provided, the battery cell comprising: a battery housing in which an electrode assembly is mounted and includes a sealing portion having a structure for sealing an outer peripheral side by heat fusion; an electrode lead electrically connected to an electrode connector included in the electrode assembly and protruding outward from the battery housing via the sealing portion; a lead film located between the electrode lead and the sealing portion; and a protective member in contact with at least a portion of the outer surface of the electrode lead, wherein the size of the protective member changes according to the temperature of the electrode lead.

[0014] The protective member extends along the width of the electrode lead and may surround the outer surface of the electrode lead.

[0015] The protective member shrinks at a first temperature along at least one of the width direction and the thickness direction of the electrode lead.

[0016] The protective components can be made of shape memory alloy (SMA).

[0017] The first temperature can be 60 degrees Celsius or higher.

[0018] The protective component can be formed at a location adjacent to the lead film.

[0019] The protective member includes a main body portion and an opening formed at the center of the main body portion, and the electrode lead is inserted into the opening, wherein the main body portion may surround the outer surface of the electrode lead.

[0020] The thickness of the opening can be greater than or equal to the thickness of the electrode lead.

[0021] An adhesive layer can be formed on at least one surface of the opening.

[0022] According to another aspect of the present invention, a battery module is provided, the battery module comprising the aforementioned battery cell.

[0023] Beneficial effects

[0024] According to embodiments of this disclosure, a protective component capable of interrupting the current flow of a battery cell can be located on the electrode leads, thereby improving safety.

[0025] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the description of the appended claims other effects not described above. Attached Figure Description

[0026] Figure 1 This is a front view showing the battery cell according to this embodiment.

[0027] Figure 2 yes Figure 1 A magnified view of region A.

[0028] Figure 3 It is shown Figure 2 A diagram of the protective components.

[0029] Figure 4 and Figure 5 It is shown Figure 1 The diagram shows region A, which is at a high temperature. Detailed Implementation

[0030] Various embodiments of this disclosure will be described in detail below with reference to the accompanying drawings to enable those skilled in the art to readily implement them. This disclosure can be modified in various different ways and is not limited to the embodiments set forth herein.

[0031] For clarity, descriptions of parts not related to this specification will be omitted, and throughout the specification, the same reference numerals denote the same elements.

[0032] Furthermore, in the accompanying drawings, for ease of description, the dimensions and thicknesses of each element are arbitrarily shown, and this disclosure is not necessarily limited to those shown in the drawings. In the accompanying drawings, the thicknesses of layers, regions, etc., are enlarged for clarity. In the accompanying drawings, the thicknesses of some layers and regions are enlarged for ease of description.

[0033] Furthermore, throughout the specification, when a section is referred to as "including" or "contains" a component, unless otherwise stated, it means that the section may also include other components, without excluding other components.

[0034] Furthermore, it should be understood that when an element such as a layer, membrane, region, or plate is referred to as being "on" or "above" another element, it can be directly on the other element or there may be intermediate elements present. Conversely, when an element is referred to as being "directly on" another element, it means that there are no other intermediate elements present. Additionally, the terms "on" or "above" refer to being positioned above or below a reference part and do not necessarily mean being positioned "on" or "above" the reference part in the opposite direction to gravity.

[0035] Furthermore, throughout the instruction manual, when referred to as a "plane," it means the target portion viewed from above, and when referred to as a "section," it means the target portion viewed from the side of a vertically cut section.

[0036] The battery cell 100 according to an embodiment of the present disclosure will now be described. However, the description will refer to the front side of the battery cell 100, but the present disclosure is not limited thereto, and the battery cell 100 will also be described in the same or similar manner, even in the case of the back side.

[0037] Figure 1 This is a front view showing the battery cell according to this embodiment.

[0038] Reference Figure 1 According to an embodiment of the present disclosure, a battery cell 100 includes an electrode assembly (not shown) and a battery casing 130. The electrode assembly includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes, and the electrode assembly is mounted to the battery casing 130. Here, the battery cell 100 may include an electrolyte solution inside the battery casing 130 and the electrode assembly (not shown).

[0039] In one example, the electrolyte solution refers to a liquid electrolyte, and ions can move between the positive and negative electrodes. The secondary battery can be charged and discharged through ion exchange between the positive and negative electrodes. The electrolyte used herein may include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc. However, this disclosure is not limited thereto.

[0040] Furthermore, the battery casing 130 has an electrode assembly (not shown) mounted therein, and includes a sealing portion 135 having a structure that seals the outer periphery by thermal melting. The battery casing 130 may be a laminated sheet comprising a resin layer and a metal layer. More specifically, the battery casing 130 is made of a laminated sheet and may include an outer resin layer forming the outermost layer, a barrier metal layer to prevent material penetration, and an inner resin layer for sealing. However, embodiments of this disclosure are not limited to the above-described structure, and a battery casing of a secondary battery with a general structure may be used instead.

[0041] Furthermore, the electrode assembly (not shown) may have a jelly roll type (wound type), a stack type (laminated type), or a composite type (stacked / folded type) structure. More specifically, the electrode assembly (not shown) may include a positive electrode, a negative electrode, and a separator disposed between them.

[0042] Furthermore, in this embodiment, the battery housing 130 may have a structure in which electrode leads 141 and 145, electrically connected to a plurality of electrode terminals (not shown) extending from an electrode assembly (not shown), are sealed to be exposed to the outside. More specifically, electrode leads 141 and 145 may protrude outward from the battery housing 130 via a sealing portion 135. Additionally, in this embodiment, lead films 151 and 155 may be located between the electrode leads 141 and 145 and the sealing portion 135.

[0043] In one example, electrode leads 141 and 145 include a positive lead 141 electrically connected to a positive terminal included in the electrode assembly and a negative lead 145 electrically connected to a negative terminal included in the electrode assembly.

[0044] Here, the battery cell 100 can be a bidirectional pouch battery cell, wherein the positive lead 141 and the negative lead 145 protrude from both sides of the battery casing 130, respectively. However, this disclosure is not limited to this, and the battery cell 100 can also be a unidirectional pouch battery cell in which the positive lead 141 and the negative lead 145 are disposed together on the same side surface of the battery casing 130. In the following description, it will be given based on a bidirectional pouch battery cell, but even in the case of a unidirectional pouch battery cell, it will be described in the same and similar manner.

[0045] The protective member 200 located on electrode leads 141 and 145 will be described below. Here, the description will focus on the end where the negative lead 145 of the battery cell 100 is located, but is not necessarily limited to this. Even in the case of the other end where the positive lead 141 is located, it will be described in the same or similar manner.

[0046] Figure 2 It is shown Figure 1 A magnified view of region A. Figure 3 It is shown Figure 2 A diagram of the protective components.

[0047] refer to Figure 2 In the battery cell 100 of this embodiment, the protective member 200 can contact at least a portion of the outer surface of the negative electrode lead 145. That is, the inner surface of the protective member 200 can contact at least a portion of the outer surface of the negative electrode lead 145. More specifically, the protective member 200 extends along the width direction of the negative electrode lead 145 and can surround the outer surface of the negative electrode lead 145.

[0048] Therefore, in this embodiment, the protection member 200 can directly receive the heat generated from the electrode leads 141 and 145, and the protection member 200 can interrupt the current flow once the battery cell 100 overheats.

[0049] Furthermore, the protective member 200 may be formed at a position adjacent to the lead film 155. More specifically, the protective member 200 is spaced apart from the sealing portion 135 and may be formed at a position adjacent to the lead film 155. Thus, the protective member 200 may have a relatively small impact on the battery cell 100 and other adjacent battery cells 100.

[0050] Reference Figure 3 The protective member 200 includes a body 210 and an opening 250 formed at the center of the body 210. In one example, the body 210 may be a frame with a frame-like or tubular structure, and the opening 250 may be the central portion of the opening of the body 210.

[0051] Reference Figure 2 and Figure 3 Electrode leads 141 and 145 are inserted into opening 250, and body 210 may surround the outer surface of electrode leads. This is one example, and protective member 200 may be formed to be bound along the width direction of electrode leads 141 and 145. However, the method of providing protective member 200 on electrode leads 141 and 145 is not limited to the above, and various methods may be used without damaging electrode leads 141 and 145.

[0052] Furthermore, the thickness of the opening 250 can be greater than or equal to the thickness of the electrode leads 141 and 145. However, the thickness of the opening 250 can be adjusted within a range without damaging the electrode leads 141 and 145, while the protective member 200 is provided on the electrode leads 141 and 145.

[0053] Furthermore, the inner surface of the protective member 200 can be attached to at least a portion of the outer surfaces of the electrode leads 141 and 145. Here, in the protective member 200, an adhesive layer 270 can be formed on at least one surface of the opening 250. That is, the adhesive layer 270 can be located between the inner surface of the protective member 200 and the outer surfaces of the electrode leads 141 and 145. In this case, the adhesive layer 270 can extend along the width direction of the electrode leads 141 and 145. However, this disclosure is not limited to this, and the protective member 200 can be fixed by the frictional force between the inner surface of the protective member 200 and the outer surfaces of the electrode leads 141 and 145.

[0054] In one example, the adhesive layer 270 may be composed of individual tapes or may be formed by applying an adhesive. More preferably, the adhesive layer 270 is coated with an adhesive or made of double-sided tape, thereby easily securing the inner surface of the protective member 200 and the outer surfaces of the electrode leads 141 and 145. However, this disclosure is not limited thereto, and any material having adhesive properties capable of securing the inner surface of the protective member 200 to the outer surfaces of the electrode leads 141 and 145 can be used without limitation.

[0055] Thus, the protective component 200 can be stably fixed to the electrode leads 141 and 145.

[0056] Figure 4 and Figure 5 It is shown Figure 1 The diagram shows region A, which is at a high temperature. Figure 4 It is shown Figure 2 The protective component 200 before shrinkage at high temperature, and Figure 5 It is shown Figure 2 The protective component 200 is shown in the figure after shrinking at high temperature.

[0057] Reference Figure 4 and Figure 5 The dimensions of the protective member 200 can vary depending on the temperature of the electrode leads 141 and 145. In other words, the dimensions of the protective member 200 may differ when the protective member 200 receives heat generated from the electrode leads 141 and 145, and when the temperature of the electrode leads 141 and 145 is generated above a first temperature. More specifically, when the temperature rises to the first temperature, the protective member 200 may shrink along at least one of the width direction and the thickness direction of the electrode leads 141 and 145. That is, as... Figure 5 As shown, a cutting line 145a can be formed on the electrode leads 141 and 145 that are in contact with the protective member 200. In other words, the electrode leads 141 and 145 can be disconnected with reference to the cutting line 145a.

[0058] In one example, the protective member 200 may be formed of a shape memory alloy (SMA). Here, the shape memory alloy has the property of shrinking to a predetermined size at a specific temperature. That is, the protective member 200 may be made of a shape memory alloy (SMA) that shrinks to a predetermined size at a first temperature.

[0059] Here, the size of the protective member 200 reduced by shape memory alloy (SMA) can be smaller than the width and / or thickness of the electrode leads 141 and 145. In other words, the size of the protective member 200 reduced by shape memory alloy (SMA) can be such that the inner surface of the protective member 200 can be subjected to pressure sufficient to damage the electrode leads 141 and 145.

[0060] More specifically, the protective member 200 can be a highly elastic material made of a shape memory alloy such as a nickel-titanium alloy. However, the protective member 200 is not limited to this, and any shape memory alloy with predetermined elasticity can be used.

[0061] Therefore, when the protective member 200 shrinks to a predetermined size at a specific temperature set by the shape memory alloy (SMA), a cutting line 145a can be formed in the electrode leads 141 and 145. That is, the stability of the battery cell 100 can be further improved, while minimizing quality deviations by automatically and physically interrupting the current flow from the inside, without the need for separate external control.

[0062] Here, the first temperature can be a temperature at which abnormal phenomena such as overcurrent flow occur. More specifically, the first temperature is a temperature exceeding the safe operating temperature range of the battery cell 100, and can be a temperature at which the battery cell 100 cannot be used. In one example, the first temperature can be 60 degrees Celsius or higher. That is, as heat is transferred at a temperature of 60 degrees Celsius or higher, the protective member 200 can be reduced in size along at least one of the width direction and the thickness direction of the electrode leads 141 and 145.

[0063] Therefore, when heat is generated due to overcurrent or other reasons in the battery cell 100, the protection member 200 shrinks at a predetermined temperature, thereby forming a cutting line 145a on the electrode leads 141 and 145. That is, considering the internal state of the battery cell 100, the current flow can be physically interrupted, thereby further improving the stability of the battery cell 100 and the safety of the user.

[0064] Here, the protective member 200 does not need to shrink when the electrode leads 141 and 145 heat up at temperatures below 60 degrees Celsius. This is because the battery cell 100 is in a simple heating state and there is no need to interrupt the current flow within the range where normal operation is possible.

[0065] On the other hand, if heat at temperatures below 60 degrees Celsius is transferred to the protective member 200 and the protective member 200 shrinks, the electrode leads 141 and 145 may be unnecessarily disconnected, and the current may be interrupted even if simple heat is generated during charging / discharging.

[0066] According to another embodiment of this disclosure, a battery module includes the aforementioned battery cells. Therefore, when heat is generated due to overcurrent or other reasons in some of the battery cells 100 within the battery module, electrode leads 141 and 145 are disconnected by the protection member 200, thereby limiting electron transfer to the other battery cell 100 that is not experiencing any abnormality. In other words, unlike the battery cells 100 where electrode leads 141 and 145 are disconnected, the battery cells 100 that are not experiencing any abnormality can operate normally, thereby preventing sudden shutdown of the device including the battery cells 100.

[0067] Furthermore, one or more battery modules according to this embodiment can also be encapsulated in a battery pack housing to form a battery pack. The aforementioned battery module and battery pack including the battery module can be applied to various devices. Such devices can be applied to vehicle devices such as electric bicycles, electric vehicles, or hybrid vehicles, but this disclosure is not limited thereto, and can be applied to various devices that can use battery modules and battery packs including battery modules, which also fall within the scope of this disclosure.

[0068] Although preferred embodiments of the present disclosure have been shown and described above, the scope of the present disclosure is not limited thereto, and many other variations and modifications can be made by those skilled in the art using the basic principles of the invention as defined in the appended claims, which also fall within the spirit and scope of the invention.

[0069] [Explanation of reference numbers]

[0070] 100: Battery cell

[0071] 130: Battery casing

[0072] 141, 145: Electrode leads

[0073] 151, 155: Lead film

[0074] 200: Protective components

[0075] 210: Main Body

[0076] 250: Opening

[0077] 270: Adhesive layer

Claims

1. A battery cell, the battery cell comprising: A battery housing having an electrode assembly mounted therein, and the battery housing including a sealing portion having a structure for sealing the outer periphery by thermal melting; Electrode leads, which are electrically connected to electrode connectors included in the electrode assembly and protrude outward from the battery housing via the sealing portion; A lead film is located between the electrode lead and the sealing portion; as well as A protective member that is in contact with at least a portion of the outer surface of the electrode lead. The dimensions of the protective component vary depending on the temperature of the electrode leads. The protective member extends along the width direction of the electrode lead and surrounds the outer surface of the electrode lead. Wherein, the protective member shrinks at least one of the width direction and the thickness direction of the electrode lead at the first temperature, and The first temperature is the temperature at which the abnormal phenomenon occurs.

2. The battery cell according to claim 1, wherein, The protective component is made of shape memory alloy SMA.

3. The battery cell according to claim 1, wherein, The first temperature is 60 degrees Celsius or higher.

4. The battery cell according to claim 1, wherein, The protective member is formed at a position adjacent to the lead film.

5. The battery cell according to claim 1, wherein, The protective member includes a main body portion and an opening formed at the center of the main body portion, and The electrode lead is inserted into the opening, wherein the body portion surrounds the outer surface of the electrode lead.

6. The battery cell according to claim 5, wherein, The thickness of the opening is greater than or equal to the thickness of the electrode lead.

7. The battery cell according to claim 6, wherein, An adhesive layer is formed on at least one surface of the opening.

8. A battery module comprising a battery cell according to any one of claims 1-7.

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