Battery module and battery pack

Abstract

A battery module and a battery pack according to one embodiment can include a case, a plurality of battery cells accommodated inside the case, and a first busbar connecting at least one battery cell among the plurality of battery cells and a conductive connector, the first busbar can include a first access portion connected to the at least one battery cell, a second access portion connected to the conductive connector, and a first connection portion connecting the first access portion and the second access portion, and the first connection portion can include a material having a lower melting point than the first access portion or the second access portion.

Description

Technical Field

[0001] This invention relates to a technology for battery modules and battery packs. Background Technology

[0002] Recently, rechargeable and dischargeable battery packs have been widely used as energy sources for wireless mobile devices and have also attracted much attention as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), electric bicycles (EBIKEs), etc., as these vehicles are considered a solution to the air pollution caused by existing gasoline and diesel vehicles that use fossil fuels.

[0003] In addition, lithium-ion batteries are primarily used as the power source for electric or hybrid vehicles. Because they require large amounts of electricity for motor operation, large-capacity battery packs are typically used, consisting of battery modules that are connected in series or parallel, each containing multiple high-power battery cells.

[0004] Compared to small mobile devices that use one or two battery cells per device, medium to large devices such as electric vehicles and electric bicycles require higher power and greater capacity. For these vehicles, multiple high-power battery cells are electrically connected to form battery modules, which meets the specifications required for high-power, high-capacity battery packs.

[0005] On the other hand, when such a secondary battery continues to undergo decomposition reactions under abnormal operating conditions (e.g., overcharging, over-discharging, high-temperature exposure, electrical short circuit, etc.), it will generate heat and gas inside. If the decomposition reaction is further promoted under the high temperature and high pressure conditions caused by this, it may also lead to fire or explosion.

[0006] In particular, this problem can lead to serious, large-capacity accidents when using high-power battery packs with multiple battery cells. When thermal runaway occurs in a specific battery module, heat-conducting material is expelled from the module, which can break the insulation between the battery module and adjacent modules. A very high current can then flow instantaneously between the battery modules, causing thermal runaway to occur in adjacent modules as well, potentially leading to a fire in the entire battery pack. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] Embodiments of the present invention provide a battery module and battery pack for secondary batteries, which prevent events such as explosions or thermal runaway occurring in the battery module from spreading to other battery modules or even the entire battery pack, thereby improving safety and reliability.

[0009] Specifically, the embodiment provides a disconnection device or electrical circuit breaker that disconnects the electrical connection between a particular battery module and adjacent structures (e.g., other battery modules) when an event such as thermal runaway occurs in a particular battery module.

[0010] (II) Technical Solution

[0011] A battery module according to one embodiment may include: a housing; a plurality of battery cells housed inside the housing; and a first busbar connecting at least one of the plurality of battery cells to a conductive connector, the first busbar including: a first access portion connected to the at least one battery cell; a second access portion connected to the conductive connector; and a first connection portion connecting the first access portion and the second access portion, wherein the first connection portion may contain a material with a melting point lower than that of the first access portion or the second access portion.

[0012] In one embodiment, the first access portion may be disposed inside the housing, the second access portion may be exposed outside the housing, and the conductive connector may be disposed outside the housing.

[0013] In one embodiment, the first access portion or the second access portion may contain copper, and the first connection portion may contain aluminum.

[0014] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the first portion and the third portion may contain a material with a melting point lower than that of the first access portion or the second access portion, and the second portion may contain the same material as that of the first access portion or the second access portion.

[0015] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the first portion may contain a material with a melting point lower than that of the first access portion.

[0016] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the second portion may contain a material with a melting point lower than that of the second access portion.

[0017] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the first portion may contain a material with a melting point lower than that of the first access portion, the second portion may contain a material with a melting point lower than that of the second access portion, and the third portion may contain a material with a melting point the same as that of the first access portion or the second access portion.

[0018] In one embodiment, the at least one battery cell may include a pouch-shaped outer casing and an electrode assembly housed within the outer casing. A sealing portion formed on the edge of the outer casing may include a weak portion with weaker sealing strength than other portions, and the first connecting portion may be disposed facing the weak portion.

[0019] In one embodiment, the first connecting portion can be welded to either the first access portion or the second access portion.

[0020] In one embodiment, the battery module may further include: a first battery cell group, including at least a first battery cell from the plurality of battery cells; a second battery cell group, adjacent to the first battery cell group, and including at least a second battery cell from the plurality of battery cells; and a second busbar electrically connecting the first battery cell group and the second battery cell group, the second busbar including: a third access portion connected to the positive terminal of the first battery cell group; a fourth access portion connected to the negative terminal of the second battery cell group; and a second connection portion connecting the third access portion and the fourth access portion.

[0021] In one embodiment, the second connecting portion may contain a material with a melting point lower than that of the third or fourth connecting portion.

[0022] In one embodiment, the second connection portion may contain aluminum, and the third or fourth access portion may contain copper.

[0023] A battery pack according to one embodiment may include: a battery pack housing; battery modules disposed inside the battery pack housing; and an inter-module busbar electrically connecting the battery modules, wherein at least one of the battery modules may include: a plurality of battery cells; and a battery module busbar of at least one of the battery modules electrically connecting at least one of the plurality of battery cells to the inter-module busbar, wherein the battery module busbar may include: a first access portion connected to the at least one battery cell; a second access portion connected to the inter-module busbar; and a first connecting portion connecting the first access portion and the second access portion, wherein the first access portion or the second access portion may contain a first material, and the first connecting portion may contain a second material with a melting point lower than the first material.

[0024] In one embodiment, the inter-module busbar may contain the first material at least in the portion that contacts the second access portion.

[0025] In one embodiment, the plurality of battery cells form a first battery cell group and a second battery cell group that are adjacent to each other, and the battery module busbar may include: a first busbar connected to the at least one battery cell and the inter-module busbar; and a second busbar connected to the battery cells of the first battery cell group and the battery cells of the second battery cell group.

[0026] In one embodiment, the first connecting portion can be welded to either the first access portion or the second access portion.

[0027] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the first portion may contain a material with a melting point lower than that of the first access portion.

[0028] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the second portion may contain a material with a melting point lower than that of the second access portion.

[0029] In one embodiment, the first connecting portion may include: a first portion forming a boundary with the first access portion; a second portion forming a boundary with the second access portion; and a third portion connecting the first portion and the second portion, wherein the first portion may contain a material with a melting point lower than that of the first access portion, the second portion may contain a material with a melting point lower than that of the second access portion, and the third portion may contain a material with a melting point the same as that of the first access portion or the second access portion.

[0030] According to one embodiment, a busbar is used to connect multiple battery modules together. The busbar may include: an inter-module busbar connecting a first battery module and a second battery module among the multiple battery modules; and a first busbar comprising multiple materials, including at least one material having a melting point lower than the other materials among the multiple materials. The first busbar connects at least one battery cell of the first battery module or the second battery module to the inter-module busbar, wherein melting of the at least one material breaks the electrical connection between the first battery module and the second battery module.

[0031] (III) Beneficial Effects

[0032] According to one embodiment of this specification, a battery module and battery pack for secondary batteries can be provided, which prevents events such as explosions or thermal runaway occurring in the battery module from spreading to other battery modules or even the entire battery pack, thereby improving safety and reliability.

[0033] According to another embodiment of this specification, a battery module may be provided with a disconnection device or circuit breaker that disconnects the electrical connection between the battery module and adjacent structures (e.g., other battery modules) when an event such as thermal runaway occurs in a particular battery module. Attached Figure Description

[0034] Figure 1 This is a perspective view of a battery module according to an embodiment of the present invention.

[0035] Figure 2 A battery pack accommodating multiple battery modules is briefly shown in another embodiment of the invention.

[0036] Figure 3 A busbar for a battery module is shown in another embodiment of the invention.

[0037] Figure 4 The connection relationship between the battery cell and the busbar is shown in another embodiment of the invention.

[0038] Figure 5A busbar including a terminal portion is shown in one embodiment of the invention.

[0039] Figure 6 The positional relationship between the fuse portion of the busbar and the sealing portion of the battery cell is shown in another embodiment of the invention.

[0040] Figure 7 The fuse portion of the busbar is shown in the first embodiment of the present invention.

[0041] Figure 8 The fuse portion of the busbar is shown in the second embodiment of the present invention.

[0042] Explanation of reference numerals in the attached figures

[0043] 100: Battery module; 110: Housing

[0044] 120: Battery cell; 121: Electrode lead

[0045] 122: Sealing part; 123: Electrode assembly

[0046] 131: First busbar; 131a: First access unit

[0047] 131b: Second access unit; 131c: First connection unit

[0048] 132: Second busbar; 132a: Third access section

[0049] 132b: Fourth Access Unit; 132c: Second Connection Unit

[0050] 1000: Battery pack; 200: Inter-module busbar

[0051] 300: Battery pack casing Detailed Implementation

[0052] The terminology used in this specification is general terminology chosen in consideration of its functionality in the various embodiments of the invention. However, these terms may vary depending on the intent of those skilled in the art, legal or technical interpretation, and the emergence of new technologies. Additionally, some terms may be arbitrarily chosen by the applicant. These terms can be interpreted according to their meanings as defined in this specification. Where no specific terminology is defined, it can also be interpreted based on the overall content of this specification and the general technical meaning of the field.

[0053] Furthermore, the same reference numerals or symbols in each of the accompanying drawings indicate parts or components that perform substantially the same function. For ease of description and understanding, the same reference numerals or symbols are also used in different embodiments. That is, even if components with the same reference numerals are shown in multiple drawings, the multiple drawings do not represent the same embodiment.

[0054] Additionally, ordinal terms such as "first" and "second" may be used in this specification to distinguish components. These ordinal numbers are used to differentiate identical or similar components from one another, and the meaning of the terms should not be interpreted limitingly based on their use. For example, the order of use or arrangement of components associated with these ordinal numbers should not be interpreted limitingly based on their numerical value.

[0055] In this specification, unless the context clearly states otherwise, singular expressions include plural expressions.

[0056] In this specification, terms such as “comprising” or “constituting” should be understood as specifying the presence of features, numbers, steps, operations, components, parts or combinations thereof described in this specification, rather than excluding the presence or additional possibilities of one or more different features, numbers, steps, operations, components, parts or combinations thereof.

[0057] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the details shown in this disclosure, which are merely illustrative of the invention.

[0058] For example, those skilled in the art who understand this invention can recognize other embodiments included within the scope of this invention by adding, changing, or deleting components, and these other embodiments should also be included within the scope of this invention.

[0059] Figure 1 This is a perspective view of a battery module 100 according to one embodiment. Figure 2 A battery pack 1000, which in another embodiment houses multiple battery modules 100, is briefly shown. Figure 3 Busbars 131, 132 of battery module 100 are shown in another embodiment. Figure 4 The connection relationship between battery cell 120 and busbars 131, 132 is shown in another embodiment.

[0060] Reference Figure 1 The battery module 100 includes a battery cell 120 disposed inside the housing 110. Figure 4 (As shown in the figure), and may include a busbar 131 electrically connected to the battery cell 120 and partially exposed outside the housing 110. See also... Figure 2Multiple battery modules 100 are disposed inside the battery pack housing 300, and the battery modules 100 are electrically connected via inter-module busbars 200. That is, one end of the inter-module busbar 200 is connected to the busbar 131 of one battery module 100, and the other end is connected to the busbar 131 of another battery module 100. Although in Figure 2 The inter-module busbar 200 shown is in the shape of a bar, but this is just an example. In other embodiments, the inter-module busbar 200 may have various shapes.

[0061] Figure 3 The accompanying drawing, with a portion of the housing 110 omitted from the battery module 100, shows busbars 131 and 132 connected to the battery cell 120. (Refer to...) Figure 4 Battery cell 120 is connected to busbars 131 and 132 via electrode leads 121.

[0062] In one embodiment, the battery module 100 may include a first busbar 131 for connecting the battery module 100 to an external device (e.g., another battery module) and / or a second busbar 132 inside the battery module 100 for electrical connections between battery cells 120.

[0063] Reference Figure 4 The three battery cells located on the far left (-Z direction) and the three battery cells located on the far right (+Z direction) are connected to the first busbar 131. A portion of the first busbar 131 (e.g., Figure 1 131b) is exposed to the outside of housing 110, thereby connecting to a conductive connector (e.g., inter-module busbar 200) disposed outside housing 110.

[0064] The second busbar 132 connects the first battery cell group 120a and the second battery cell group 120b. The second busbar 132 is electrically connected to the first electrode lead 121a of the first battery cell group 120a and to the second electrode lead 121b of the second battery cell group 120b. The first electrode lead 121a and the second electrode lead 121b have different polarities. For example, the first electrode lead 121a can be a positive electrode lead, and the second electrode lead 121b can be a negative electrode lead.

[0065] Figure 5 A busbar is shown in one embodiment, including an externally exposed access section. Figure 6 The positional relationship between the busbar and the battery cell 120 is shown in another embodiment.

[0066] Reference Figure 5 and Figure 6In one embodiment, the first busbar 131 may include a first access portion 131a connected to the battery cell 120 and a second access portion 131b exposed outside the housing 110. Electrode leads 121 of the battery cell 120 are connected to slots 133 in the first access portion 131a. The first access portion 131a may include a number of slots 133 equal to the number of connected battery cells 120.

[0067] The first busbar 131 may include a first connecting portion 131c connecting the first access portion 131a and the second access portion 131b. (See also...) Figure 1 or Figure 2 The second access portion 131b extends from the end of the first connection portion 131c in the -X direction to be exposed outside the housing 110 and is connected to the inter-module busbar 200 that is electrically connected to the adjacent battery module 100.

[0068] In another embodiment, the first connecting portion 131c may contain a material different from the first access portion 131a or the second access portion 131b. In one embodiment, the first connecting portion 131c may contain a material with a melting point lower than that of the first access portion 131a or the second access portion 131b. For example, the first access portion 131a and the second access portion 131b may contain copper, and the first connecting portion 131c may contain aluminum. As another example, the second access portion 131b may contain copper, and the first access portion 131a and the first connecting portion 131c may contain aluminum. Yet another example, the first access portion 131a may contain copper, and the second access portion 131b and the first connecting portion 131c may contain aluminum.

[0069] In one embodiment, the first busbar 131 provides an electrical path between the first access portion 131a and the second access portion 131b. One end of the electrical path is connected to the first access portion 131a, and the other end is connected to the second access portion 131b, and the first connecting portion 131c serves as the path between the two ends.

[0070] In another embodiment, during the flow of current from the first access portion 131a to the second access portion 131b, at least a portion of the current passes through a section formed by a material with a melting point lower than that of the other sections. In yet another embodiment, the electrical path may include a first section connected to the first access portion 131a, a second section connected to the second access portion 131b, and a third section between the first and second sections, and the portion of the first busbar 131 corresponding to the third section may contain a material with a melting point lower than that of the portions corresponding to the first or second sections.

[0071] For example, the first and second intervals can contain copper, and the third interval can contain aluminum. As another example, the second interval can contain copper, and the first and third intervals can contain aluminum. Yet another example, the first interval can contain copper, and the second and third intervals can contain aluminum. Although specified here as copper and aluminum, alloys of these materials can be used, especially aluminum alloys, whose melting points can be varied to be lower or higher depending on the alloy.

[0072] When thermal runaway occurs inside the battery module 100, high-temperature gases, flames, etc., will be ejected from the battery cell 120 into the interior and exterior of the housing 110. Since the melting point of the first connection portion 131c is lower than that of other portions (e.g., the first access portion 131a and / or the second access portion 131b), it will melt more quickly, which can initially sever the electrical connection between the first access portion 131a and the second access portion 131b.

[0073] The flames or gases ejected from the battery module 100 that has experienced thermal runaway may contain conductive particles. These conductive particles not only severely affect the battery module 100 that has experienced thermal runaway, but also affect the components of the battery pack (e.g., Figure 2 The battery pack 1000 could be severely affected by other battery modules. For example, conductive particles could break the insulation between battery cell 120 and housing 110 or between battery module 100 and battery pack housing 300, potentially causing a fire in the entire battery pack 1000. According to one embodiment, in the event of an event such as thermal runaway, the first connection 131c can be rapidly melted to quickly cut off the electrical path between battery modules 100 and suppress the propagation of thermal runaway.

[0074] In one embodiment, the first connecting portion 131c may be made of two or more materials. In one embodiment, the first connecting portion 131c is divided into a first portion 131c-1 that forms a boundary with the first access portion 131a, a second portion 131c-2 that forms a boundary with the second access portion 131b, and a third portion 131c-3 that connects the first portion 131c-1 and the second portion 131c-2, and each portion may contain a different material than the adjacent portions.

[0075] In one embodiment, the first portion 131c-1 and the second portion 131c-2 may contain a material with a melting point lower than that of the first access portion 131a or the second access portion 131b, and the third portion 131c-3 may contain the same material as the first access portion 131a or the second access portion 131b. For example, the first access portion 131a, the second access portion 131b, and the third portion 131c-3 may contain copper, and the first portion 131c-1 and the second portion 131c-2 may contain aluminum.

[0076] On the other hand, the material constituting the first connecting portion 131c is more likely to melt in the event of thermal runaway than the first access portion 131a or the second access portion 131b, thereby enabling the rapid severing of the electrical connection between the first access portion 131a and the second access portion 131b. However, this disclosure is not limited to... Figure 5 The example shown. Figure 5 The third part 131c-3 is shown to contain a material different from that of the first part 131c-1 or the second part 131c-2, but this is just an example and the third part 131c-3 may also be formed of the same material as the first part 131c-1 or the second part 131c-2.

[0077] Reference Figure 2 The second access portion 131b can contact the inter-module bus 200. If the second access portion 131b and the inter-module bus 200 are made of different materials, losses may occur due to contact resistance. Therefore, the inter-module bus 200 and the second access portion 131b should at least be made of the same material in the parts that contact each other to help reduce losses caused by contact resistance. Therefore, in one embodiment, the second access portion 131b and the inter-module bus 200 may contain copper, and the first connection portion 131c may contain aluminum.

[0078] In another embodiment, the first busbar 131 can be made by friction stir welding two components of different materials. For example, the first access portion 131a and the second access portion 131b made of copper and the first connecting portion 131c made of aluminum can be joined together by friction stir welding to form an integral first busbar 131.

[0079] On the other hand, the first busbar 131 is not limited to Figure 5 The shape shown can be configured in various ways to electrically connect the battery cell 120 to other structures outside the battery module 100 (e.g., other battery modules 100).

[0080] Reference Figure 6 The battery cell 120 includes an electrode assembly 123 and an outer casing material covering the electrode assembly 123. The battery cell 120 includes a sealing portion 122 at the edge of the outer casing material. For example, the sealing portion 122 is the portion where two sheet members, respectively covering both sides of the electrode assembly 123, are joined together at their edges. The sealing portion 122 seals the interior from the outside of the outer casing material. Alternatively, the outer casing material may be configured as a sheet member folded to cover the electrode assembly 123.

[0081] In another embodiment, the first connecting portion 131c may be positioned corresponding to the sealing portion 122 of the battery cell 120. When a short circuit occurs inside the electrode assembly 123, generating gas or flame, the pressure inside the outer casing increases, and the flame or gas can be ejected through the sealing portion 122 to the outside of the outer casing. The flame or gas can be ejected through a portion of the sealing portion 122 to the outside of the battery cell 120 and can melt the first connecting portion 131c to sever the connection between the first access portion 131a and the second access portion 131b.

[0082] In another embodiment, the sealing portion 122 may include a weak portion 122a with weaker sealing strength. Since flames or gases can escape from the weaker portion, positioning the weak portion 122a and the first connecting portion 131c in corresponding positions allows for effective disconnection of the electrical connection between the first connecting portion 131a and the second connecting portion 131b in the event of thermal runaway. This is because the first connecting portion 131c can melt more rapidly when positioned close to the weak portion 122a. For example, see reference... Figure 6 The weak part 122a and the first connecting part 131c can be arranged facing each other in the X direction.

[0083] On the other hand, in the battery module 100, the weak point 122a is not a necessary component. Figure 6 The weak part 122a can be omitted. When thermal runaway occurs, the temperature inside the housing 110 becomes so high that the first connection 131c can be melted even without a separate structure to guide the flame or gas to the first connection 131c, causing the first busbar 131 to break.

[0084] In another embodiment, an insulating member 140 may be further provided between the first busbar 131 and the battery cell 120. Electrode leads 121 can pass through holes 141 in the insulating member 140 and connect to the first access portion 131a. In one embodiment, the insulating member 140 may include a gas guide 142 located on the portion facing the first connection portion 131c and communicating between both sides of the insulating member 140. When gas or flame is ejected from the battery cell 120 disposed on one side of the insulating member 140, the gas or flame can rapidly reach the first connection portion 131c through the gas guide 142 of the insulating member 140 and rapidly melt the first connection portion 131c. That is, by providing a gas guide 142 on the insulating member 140, the electrical connection between the battery modules 100 can be rapidly severed in the event of thermal runaway. However, the gas guide 142 is not an essential component of the present invention. When the insulating component 140 is made of a material with a low melting point (e.g., plastic) or its thickness is relatively thin, it is easily cleared in the early stages in the event of thermal runaway, so the insulating component 140 does not obstruct the flame or gas ejected from the battery cell 120 from reaching the first connection 131c.

[0085] Figure 7 The second busbar 132 in the first embodiment is shown. Figure 8 The second busbar 132 in the second embodiment is shown. See also... Figure 7 and Figure 8 as well as Figure 4 The second busbar 132 will be explained.

[0086] Reference Figure 4 In one embodiment, the second busbar 132 is configured to connect a first battery cell group 120a and a second battery cell group 120b disposed inside the housing 110. The first battery cell group 120a and the second battery cell group 120b are adjacent to each other and may include at least one battery cell 120. In the illustrated embodiment, the first battery cell group 120a and the second battery cell group 120b each include three battery cells 120, but this is only an example, and the first battery cell group 120a or the second battery cell group 120b may consist of two or fewer battery cells 120 or more battery cells 120.

[0087] In another embodiment, the second busbar 132 is electrically connected to the positive terminal of the first battery cell group 120a and the negative terminal of the second battery cell group 120b. Alternatively, the second busbar 132 is electrically connected to the negative terminal of the first battery cell group 120a and the positive terminal of the second battery cell group 120b. For example, the second busbar 132 is electrically connected to the first electrode lead 121a of the first battery cell group 120a and the second electrode lead 121b of the second battery cell group 120b, in which case the first electrode lead 121a and the second electrode lead 121b have different polarities. For example, the first electrode lead 121a can be the positive terminal of the first battery cell group 120a, and the second electrode lead 121b can be the negative terminal of the second battery cell group 120b.

[0088] Reference Figure 7 and Figure 8 The second busbar 132 includes a third access portion 132a connected to the first battery cell group 120a and a fourth access portion 132b connected to the second battery cell group 120b. For example, the positive lead of the first battery cell group 120a can be connected to the first gap 134a of the third access portion 132a, and the negative lead of the second battery cell group 120b can be connected to the second gap 134b of the fourth access portion 132b. That is, the third access portion 132a and the fourth access portion 132b have different polarities.

[0089] In the illustrated embodiment, three battery cells 120 are connected to the third access section 132a and three battery cells 120 are connected to the fourth access section 132b. However, this is only an example. In other embodiments, one, two or more battery cells 120 may be connected to the third access section 132a or the fourth access section 132b.

[0090] In another embodiment, the second busbar 132 includes a second connecting portion 132c connecting the third access portion 132a and the fourth access portion 132b. In one embodiment, the second connecting portion 132c may contain a material different from that of the third access portion 132a or the fourth access portion 132b. In another embodiment, the second connecting portion 132c may contain a material with a melting point lower than that of the third access portion 132a or the fourth access portion 132b.

[0091] For example, refer to Figure 7 The third access portion 132a and the fourth access portion 132b may contain copper, and the second connection portion 132c may contain aluminum. For example, see reference... Figure 8 The fourth access portion 132b may contain copper, and the third access portion 132a and the second connection portion 132c may contain aluminum. In another example, the third access portion 132a may contain copper, and the fourth access portion and the second connection portion 132c may contain aluminum.

[0092] When flames or gases are ejected outside the battery cell 120 due to abnormal operation of the battery cell 120, the second connection portion 132c melts faster than other portions, thereby effectively severing the electrical connection between the first battery cell group 120a and the second battery cell group 120b.

[0093] The housing 110 of the battery module 100 contains conductive material, and for insulation between the second busbar 132 and the housing 110, the second busbar 132 and the housing 110 are spaced apart by a distance sufficient to maintain insulation between them. However, the gas ejected from the battery cell 120 to the outside may contain conductive particles, which may shorten the insulation distance between the second busbar 132 and the housing 110, thereby breaking the insulation between them. If the connection between the third access portion 132a and the fourth access portion 132b is maintained in the event of a fire, the damage caused by the overcurrent will not only propagate to the battery cell 120 inside the housing 110, but also to other battery modules 100 outside.

[0094] According to one embodiment, the second busbar 132 includes a second connecting portion 132c that can be rapidly melted by flame or gas, and in the event of thermal runaway, the electrical path provided by the second busbar 132 can be quickly cut off by melting the second connecting portion 132c. This can prevent the fire from spreading to other battery cells 120 or other battery modules 100.

[0095] In another embodiment, the second busbar 132 can be made by welding two components of different materials. For example, the third access portion 132a and the fourth access portion 132b made of copper and the second connecting portion 132c made of aluminum can be combined to form an integral second busbar 132 by means of friction stir welding, rotary friction welding, laser welding, ultrasonic welding, etc.

[0096] On the other hand, the second busbar 132 is not limited to Figure 7 and Figure 8 The shape shown can be configured to be various shapes that enable electrical connection between battery cells 120.

[0097] In one aspect of this disclosure, the busbar (such as Figure 2(As shown) multiple battery modules are connected together. The busbar may include: a) an inter-module busbar connecting a first battery module and a second battery module among the multiple battery modules; and b) a first busbar connected in series with the inter-module busbar and comprising multiple materials, including at least one material with a melting point lower than other materials among the multiple materials, and the first busbar connecting at least one battery cell of the first battery module or the second battery module to the inter-module busbar, wherein melting of at least one material disconnects the electrical connection between the first battery module and the second battery module.

[0098] The structure and features of the present invention have been described above based on various embodiments thereof, but the present invention is not limited thereto. It will be obvious to those skilled in the art that various changes or modifications can be made within the spirit and scope of the present invention, and therefore such changes or modifications should be included within the scope of the claims.

Claims

1. A battery module, comprising: case; Multiple battery cells are housed inside the casing; as well as The first busbar connects at least one of the plurality of battery cells to a conductive connector. The first bus bar includes: A first access unit is connected to the at least one battery cell; The second access portion is connected to the conductive connector; and The first connecting part connects the first access part and the second access part. The first connecting portion comprises a material with a melting point lower than that of the first access portion or the second access portion. The at least one battery cell includes a pouch-shaped outer casing and an electrode assembly housed within the outer casing. The outer casing material includes a sealing portion formed on the edge of the outer casing material, the sealing portion including a weak portion with weaker sealing strength than other parts. The first connecting portion is disposed facing the weak portion in the same direction.

2. The battery module according to claim 1, wherein, The first access portion is disposed inside the housing, the second access portion is exposed outside the housing, and the conductive connector is disposed outside the housing.

3. The battery module according to claim 1, wherein, The first access portion or the second access portion contains copper, and the first connection portion contains aluminum.

4. The battery module according to claim 1, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The first portion and the third portion contain materials with a melting point lower than that of the first access portion or the second access portion, and the second portion contains the same material as the first access portion or the second access portion.

5. The battery module according to claim 1, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The first part contains a material with a melting point lower than that of the first access portion.

6. The battery module according to claim 1, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The second part contains a material with a melting point lower than that of the second access portion.

7. The battery module according to claim 1, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The first part contains a material with a melting point lower than that of the first access portion, the second part contains a material with a melting point lower than that of the second access portion, and the third part contains a material with a melting point the same as that of the first access portion or the second access portion.

8. The battery module according to claim 1, wherein, The first connecting portion is joined to the first access portion or the second access portion by welding.

9. The battery module according to claim 1, further comprising: The first battery cell group includes at least the first battery cell among the plurality of battery cells; The second battery cell group is adjacent to the first battery cell group and includes at least the second battery cell from the plurality of battery cells; as well as The second busbar electrically connects the first battery cell group and the second battery cell group. The second busbar includes: The third access section is connected to the positive terminal of the first battery cell group; The fourth access section is connected to the negative terminal of the second battery cell group; and The second connection unit connects the third access unit and the fourth access unit.

10. The battery module according to claim 9, wherein, The second connecting portion contains a material with a melting point lower than that of the third or fourth connecting portion.

11. The battery module according to claim 10, wherein, The second connection portion comprises aluminum, and the third or fourth connection portion comprises copper.

12. A battery pack, comprising: Battery pack casing; The battery module is located inside the battery pack housing; as well as Inter-module busbars electrically connect the battery modules. At least one of the battery modules includes: Multiple battery cells; and At least one of the battery modules has a battery module busbar that electrically connects at least one of the plurality of battery cells to the inter-module busbar. The battery module busbar includes: A first access unit is connected to the at least one battery cell; The second access unit is connected to the inter-module busbar; and The first connecting part connects the first access part and the second access part. The first access portion or the second access portion comprises a first material, and the first connecting portion comprises a second material with a melting point lower than that of the first material. At least one of the plurality of battery cells includes a pouch-shaped outer casing and an electrode assembly housed within the outer casing. The outer casing material includes a sealing portion formed on the edge of the outer casing material, the sealing portion including a weak portion with weaker sealing strength than other parts. The first connecting portion is disposed facing the weak portion in the same direction.

13. The battery pack according to claim 12, wherein, The inter-module busbar contains the first material at least in the portion that contacts the second access section.

14. The battery pack according to claim 12, wherein, The multiple battery cells form a first battery cell group and a second battery cell group that are adjacent to each other. The battery module busbar includes: A first busbar is connected to the at least one battery cell and the inter-module busbar; and The second busbar connects to the battery cells of the first battery cell group and the battery cells of the second battery cell group.

15. The battery pack according to claim 12, wherein, The first connecting portion is joined to the first access portion or the second access portion by welding.

16. The battery pack according to claim 12, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The first part contains a material with a melting point lower than that of the first access portion.

17. The battery pack according to claim 12, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The second part contains a material with a melting point lower than that of the second access portion.

18. The battery pack according to claim 12, wherein, The first connecting part includes: The first part forms a boundary with the first access part; The second part forms a boundary with the second access portion; and The third part connects the first part and the second part. The first portion contains a material with a melting point lower than that of the first access portion, and the second portion contains a material with a melting point lower than that of the second access portion. The third part contains a material with the same melting point as the first access part or the second access part.

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