Battery pack and electric device
By incorporating an internal short-circuit device within the battery cell, rapid energy release during thermal runaway of lithium-ion batteries is achieved, resolving safety hazards associated with thermal runaway and improving the safety of the battery pack.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUNWODA MOBILITY ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2026-03-10
- Publication Date
- 2026-06-23
AI Technical Summary
When lithium-ion batteries experience thermal runaway, energy and heat cannot be effectively dissipated, leading to significant safety risks.
An internal short-circuit device is installed inside the battery cell casing, including a first conductive element and a second conductive element. During normal operation, the device remains insulated, and during thermal runaway, it is electrically connected through a drive component to achieve an internal short circuit between the positive and negative tabs, thereby rapidly releasing the battery cell's energy.
By designing an internal short-circuit device, the energy of the battery cell can be released quickly in a short time, reducing the possibility of safety accidents and improving the safety of the battery pack.
Smart Images
Figure CN122267448A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of battery technology, specifically relating to a battery pack and electrical equipment. Background Technology
[0002] Lithium-ion batteries have advantages such as high energy density, high power density, high operating voltage, light weight, small size, long cycle life, good safety, and environmental friendliness.
[0003] In related technologies, lithium-ion batteries are prone to thermal runaway when encountering accidents such as collisions or overcharging. Thermal runaway may further lead to accidents such as battery combustion or explosion.
[0004] Currently, existing batteries can protect themselves in the event of thermal runaway by cutting off the circuit with a current cutoff device or releasing pressure through a pressure relief valve. However, the energy and heat inside the battery are not dissipated, and the battery still poses a high risk. Summary of the Invention
[0005] This application aims to provide a battery pack and electrical device that can solve the problem that the energy and heat inside the battery are not dissipated, resulting in the battery still having a high degree of danger.
[0006] To solve the above-mentioned technical problems, this application is implemented as follows: In a first aspect, embodiments of this application propose a battery pack including a battery cell. The battery cell includes a housing, an electrode assembly, and an internal short-circuit device. The electrode assembly is disposed within the housing, and one side of the electrode assembly has a positive tab and a negative tab. The internal short-circuit device includes a first conductive element, a second conductive element, and a driving component. The first conductive element is electrically connected to the positive tab, and the second conductive element is electrically connected to the negative tab. The first conductive element has a first conductive end away from the positive tab, and the second conductive element has a second conductive end away from the negative tab. The first conductive end and the second conductive end are opposite to each other, and there is an insulating gap between them to achieve mutual insulation. The driving component is located on the side of the first conductive end away from the second conductive end. When the battery cell experiences thermal runaway, the driving component is at least partially capable of moving in response to thermal runaway, so as to electrically connect the first conductive end and the second conductive end.
[0007] Optionally, the internal short-circuit device further includes an insulating shell, which is disposed inside and connected to the housing. The insulating shell has a mounting cavity, and the first conductive end and the second conductive end respectively pass through the insulating shell and extend into the mounting cavity. The driving assembly is disposed inside the mounting cavity and connected to the insulating shell.
[0008] Optionally, the internal short-circuit device further includes an insulating element disposed in the insulation gap and connected to at least one of the first conductive end and the second conductive end; the driving assembly includes a conductive movable element located on the side of the first conductive end away from the second conductive end; when the cell experiences thermal runaway, the conductive movable element can pass through the first conductive end and the insulating element and contact the second conductive end, and the first conductive end and the second conductive end form an electrical connection through the conductive movable element.
[0009] Optionally, the first conductive end is provided with a first through hole, and the insulating member is provided with a second through hole. The first through hole and the second through hole are connected to form a channel, and the conductive movable member is provided corresponding to the first through hole. When the battery cell experiences thermal runaway, the conductive movable member can pass through the channel, and the conductive movable member is electrically connected to the first conductive end and the second conductive end respectively.
[0010] Optionally, the conductive movable component has a conductive tip, which is disposed toward the first conductive end; when the battery cell experiences thermal runaway, the conductive tip can pierce the first conductive end and the insulating component, and electrically connect the conductive movable component to the first conductive end and the second conductive end.
[0011] Optionally, the first conductive end is provided with a first thinning region, which is provided corresponding to the conductive tip.
[0012] Optionally, the drive assembly further includes a first elastic element and a locking element. The first elastic element is connected between the insulating shell and the conductive movable element, and the locking element is used to lock the first elastic element in a deformed state. When the battery cell experiences thermal runaway, the locking element releases the locking of the first elastic element, so that the first elastic element can change from a deformed state to a free state, thereby driving the conductive movable element to pass through the first conductive end and the insulating element and contact the second conductive end.
[0013] Optionally, the first elastic element is made of a shape memory alloy.
[0014] Optionally, the locking element is a hot-melt material layer, which covers the outer peripheral surface of the first elastic element.
[0015] Optionally, the battery pack further includes a control module and a heating element, the heating element being connected to the locking element and electrically connected to the control module, the control module being used to control the heating element to heat the locking element when the battery cell experiences thermal runaway.
[0016] Optionally, the internal short-circuit device further includes a thermoplastic insulating layer disposed in the insulating gap and connected to at least one of the first conductive end and the second conductive end; the driving component includes a second elastic member, one end of which is connected to the insulating shell, and the other end of which abuts against the first conductive end, so that the second elastic member is in a deformed state; when the battery cell experiences thermal runaway, the thermoplastic insulating layer can melt, and the second elastic member changes from the deformed state to a free state, thereby driving the first conductive end to approach the second conductive end and electrically connect with the second conductive end.
[0017] Optionally, the battery pack further includes a control module and a heating element. The heating element is connected to the thermoplastic insulation layer and electrically connected to the control module. The control module is used to control the heating element to heat the thermoplastic insulation layer when the battery cell experiences thermal runaway.
[0018] Optionally, the first conductive end has a plurality of conductive protrusions on the side facing the second conductive end, and the hot-melt insulating layer is at least disposed between the conductive protrusions and the second conductive end. The plurality of conductive protrusions are arranged at intervals, and a gap is formed between two adjacent conductive protrusions. The heating element includes a heating part, which is disposed in the gap.
[0019] Optionally, the control module includes a control unit and a sensor, the sensor being electrically connected to the control unit, the sensor being used to sense the operating state of the battery cell, and the control unit being used to control the operation of the heating element based on the sensing result of the sensor.
[0020] Secondly, embodiments of this application provide an electrical device including the battery pack described in any of the above embodiments.
[0021] In this embodiment, an internal short-circuit device is provided within the cell casing. The first conductive element of the internal short-circuit device is electrically connected to the positive tab of the electrode assembly, and the second conductive element is electrically connected to the negative tab of the electrode assembly. Insulation is achieved by setting the first conductive end of the first conductive element and the second conductive end of the second conductive element opposite each other and having an insulating gap. Thus, during normal operation of the cell, the first and second conductive ends are mutually insulated, and current flows from the positive tab to the external electrical device and then back to the negative tab. When thermal runaway occurs in the cell, the drive assembly can move at least partially, thereby electrically connecting the first and second conductive ends. This short-circuit connection between the positive and negative tabs of the cell allows current to flow directly from the positive tab to the negative tab, rapidly releasing the cell's energy in a short time, reducing the energy within the cell, lowering the possibility of a cell-related safety accident, and thus improving the overall safety of the battery pack.
[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0023] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a partial cross-sectional view of a battery cell according to an embodiment of this application; Figure 2 This is a circuit schematic diagram according to an embodiment of this application; Figure 3 This is a first structural diagram of an internal short-circuit device according to an embodiment of this application; Figure 4 This is a first cross-sectional view of the first conductive element, the second conductive element, the conductive movable element, and the insulating element according to an embodiment of this application; Figure 5 This is a second cross-sectional view of the first conductive element, the second conductive element, the conductive movable element, and the insulating element according to an embodiment of this application; Figure 6 This is a second structural diagram of the internal short-circuit device according to an embodiment of this application; Figure 7 This is a perspective view of the first conductive element and the second heating element according to an embodiment of this application; Figure 8 This is a bottom view of the first conductive element and the second heating element according to an embodiment of this application.
[0024] Figure label: 10. Battery cell; 20. Housing; 30. Electrode assembly; 31. Positive tab; 32. Negative tab; 40. Internal short-circuit device; 41. First conductive element; 411. First through hole; 412. First thinning area; 413. Conductive protrusion; 414. First conductive end; 42. Second conductive element; 421. Second conductive end; 43. Insulating shell; 44. Mounting cavity; 45. Insulating element; 451. Second through hole; 452. Second thinning area; 46. Hot-melt insulating layer; 47. Insulating gap; 50. Heating element; 51. Heating section; 65. Control module; 60. Control unit; 70. Sensing element; 80. Drive assembly; 81. First elastic element; 82. Locking element; 83. Second elastic element; 90. Conductive moving element; 91. Conductive tip. Detailed Implementation
[0025] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0026] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0027] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0029] The battery pack and electrical equipment provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.
[0030] like Figure 1As shown, a battery pack according to some embodiments of this application includes a battery cell 10. The battery cell 10 includes a housing 20, an electrode assembly 30, and an internal short-circuit device 40. The electrode assembly 30 is disposed within the housing 20, and one side of the electrode assembly 30 has a positive electrode tab 31 and a negative electrode tab 32. The internal short-circuit device 40 includes a first conductive element 41, a second conductive element 42, and a drive assembly 80. The first conductive element 41 is electrically connected to the positive electrode tab 31, and the second conductive element 42 is electrically connected to the negative electrode tab 32. The first conductive element 41 has a first conductive element away from the positive electrode tab 31. The first conductive end 414 and the second conductive element 42 have a second conductive end 421 away from the negative electrode tab 32. The first conductive end 414 and the second conductive end 421 are opposite to each other and there is an insulating gap 47 between them to achieve mutual insulation. The drive assembly 80 is connected to the housing 20. The drive assembly 80 is located on the side of the first conductive end 414 away from the second conductive end 421. When the cell 10 experiences thermal runaway, the drive assembly 80 can at least partially move in response to thermal runaway so that the first conductive end 414 and the second conductive end 421 are electrically connected.
[0031] In this embodiment, an internal short-circuit device 40 is provided inside the housing 20 of the battery cell 10. The first conductive element 41 of the internal short-circuit device 40 is electrically connected to the positive electrode tab 31 of the electrode assembly 30, and the second conductive element 42 is electrically connected to the negative electrode tab 32 of the electrode assembly 30. By setting the first conductive end 414 of the first conductive element 41 and the second conductive end 421 of the second conductive element 42 opposite to each other and having an insulation gap 47, the first conductive end 414 and the second conductive end 421 are insulated from each other. In this way, when the battery cell 10 is working normally, the first conductive end 414 and the second conductive end 421 are mutually insulated, and the current flows from the positive electrode tab 31 to the external electrical equipment and then back to the negative electrode tab 32. When the battery cell 10 experiences thermal runaway, the drive assembly 80 can at least partially move in response to the thermal runaway, thereby electrically connecting the first conductive terminal 414 with the second conductive terminal 421. In this way, the positive electrode 31 and the negative electrode 32 of the battery cell 10 are short-circuited, and the current flows directly from the positive electrode 31 to the negative electrode 32, rapidly releasing the energy of the battery cell 10 in a short time, reducing the energy inside the battery cell 10, reducing the possibility of a safety accident of the battery cell 10, and thus improving the safety of the entire battery pack.
[0032] In addition, the driving component 80 of this application is disposed on the side of the first conductive end 414 away from the second conductive end 421. In the event of thermal runaway, the first conductive end 414 is electrically connected to the second conductive end 421 under the action of the driving component 80, thereby improving the timeliness and reliability of the electrical connection between the first conductive end 414 and the second conductive end 421.
[0033] In specific applications, the battery pack can be at least one of lithium-ion battery packs, solid-state battery packs, lead-acid battery packs, and nickel-metal hydride battery packs. Those skilled in the art can flexibly configure it according to the actual situation, and the embodiments of this application do not limit it in this regard.
[0034] Specifically, such as Figure 1 As shown, the first conductive element 41 of the internal short-circuit device 40 is electrically connected to the positive electrode 31. The first conductive element 41 can be made of a metal material, and can be made of the same material as the positive electrode 31, for example, both being made of aluminum. Using the same material also makes it easier for the first conductive element 41 and the positive electrode 31 to achieve electrical connection.
[0035] like Figure 1 As shown, the second conductive element 42 of the internal short-circuit device 40 is electrically connected to the negative electrode 32. The second conductive element 42 can be made of a metal material, and can be made of the same material as the negative electrode 32, for example, both can be made of copper. Using the same material makes it easier for the second conductive element 42 and the negative electrode 32 to be electrically connected.
[0036] The materials used to manufacture the first conductive element 41 and the second conductive element 42 can be flexibly set according to actual conditions, and this application embodiment does not limit this.
[0037] like Figure 3 , Figure 4 and Figure 6 As shown, the end of the first conductive element 41 furthest from the positive electrode 31 forms a first conductive end 414, and the end of the second conductive element 42 furthest from the negative electrode 32 forms a second conductive end 421. The first conductive end 414 and the second conductive end 421 are positioned opposite each other, and an insulating gap 47 exists between them to achieve insulation between the first conductive end 414 and the second conductive end 421. Thus, when the battery cell 10 is operating normally, the first conductive end 414 and the second conductive end 421 cannot be electrically connected due to the presence of the insulating gap 47. Current flows normally from the positive electrode 31 to the external electrical equipment and then back to the negative electrode 32, enabling normal power supply to the battery cell 10.
[0038] like Figure 3 and Figure 6 As shown, the drive component 80 is located on the side of the first conductive end 414 away from the second conductive end 421. When the battery cell 10 experiences thermal runaway, the drive component 80 can at least partially move in response to the thermal runaway, thereby making the first conductive end 414 and the second conductive end 421 electrically connected, realizing an internal short circuit between the positive electrode 31 and the negative electrode 32, and the energy of the battery cell 10 is rapidly consumed in a short time, reducing the energy of the battery cell 10.
[0039] In some embodiments, the first conductive end 414 and the second conductive end 421 may remain fixed, while a portion of the driving component 80 may move, such that the first conductive end 414 and the second conductive end 421 may be electrically connected through the moving portion of the driving component 80.
[0040] In other embodiments, the first conductive end 414 can be moved under the action of the driving component 80, and the first conductive end 414 gradually approaches the second conductive end 421, and finally achieves electrical connection with the second conductive end 421.
[0041] The first conductive terminal 414 and the second conductive terminal 421 can also be electrically connected in other ways, which can be flexibly set according to the actual situation. This application embodiment does not limit this.
[0042] Optionally, such as Figure 3 and Figure 6 As shown, the internal short-circuit device 40 also includes an insulating shell 43, which is disposed inside and connected to the housing 20. The insulating shell 43 has a mounting cavity 44. The first conductive end 414 and the second conductive end 421 respectively pass through the insulating shell 43 and extend into the mounting cavity 44. The drive assembly 80 is disposed inside the mounting cavity 44 and connected to the insulating shell 43.
[0043] In this embodiment, by integrating components such as the first conductive terminal 414, the second conductive terminal 421, and the driving component 80 within the insulating shell 43, the insulating shell 43 forms a mounting support component, enabling the installation of components such as the first conductive terminal 414, the second conductive terminal 421, and the driving component 80. Furthermore, the entire internal short-circuit device 40 forms an independent component, facilitating installation. Simultaneously, the insulating shell 43 is insulated from other components within the battery cell 10, forming a closed space. This prevents the harsh environment within the battery cell 10's casing 20 (such as electrolyte vapor, active material particles, etc.) from affecting the internal short-circuit device 40, ensuring its normal performance.
[0044] Specifically, such as Figure 3 and Figure 6 As shown, an installation cavity 44 is formed inside the insulating shell 43, and the installation cavity 44 accommodates and installs the first conductive end 414, the second conductive end 421, and the driving assembly 80.
[0045] It is understood that the first conductive end 414 of the first conductive element 41 extends into the insulating shell 43, while the rest of the first conductive element 41 is located outside the insulating shell 43. The connection between the first conductive end 414 and the insulating shell 43 needs to be sealed, for example, by applying insulating glue, so as to prevent the electrolyte in the shell 20 of the battery cell 10 from entering the insulating shell 43.
[0046] Similarly, the connection between the second conductive end 421 and the insulating shell 43 is also sealed, and can be set with reference to the first conductive end 414.
[0047] The insulating shell 43 can be made of insulating material and must be able to withstand the high temperature inside the shell 20. Therefore, the insulating shell 43 can be made of high-temperature resistant engineering plastics (such as PPS, PI, etc.).
[0048] In some embodiments, since the positive tab 31 and negative tab 32 of the battery cell 10 are both located near the top of the battery cell 10, the insulating shell 43 can be connected to the top wall of the housing 20 for easy installation.
[0049] It should be noted that the housing 20 of the battery cell 10 includes a housing body and a top cover assembly. An opening is formed at the top of the housing body, and the top cover assembly is connected to the opening to close it. The top cover assembly forms the top wall of the housing 20. In other words, the insulating shell 43 can be connected to the top cover assembly.
[0050] Optionally, such as Figure 3 As shown, the internal short-circuit device 40 also includes an insulating member 45, which is disposed in the insulating gap 47 and connected to at least one of the first conductive end 414 and the second conductive end 421; the drive assembly 80 includes a conductive movable member 90, which is located on the side of the first conductive end 414 away from the second conductive end 421; when the cell 10 experiences thermal runaway, the conductive movable member 90 can pass through the first conductive end 414 and the insulating member 45 and contact the second conductive end 421, and the first conductive end 414 and the second conductive end 421 are electrically connected through the conductive movable member 90.
[0051] In this embodiment, by providing an insulating element 45 in the insulating gap 47, the insulating element 45 has good insulation performance, thereby improving the insulation performance between the first conductive end 414 and the second conductive end 421, ensuring the reliability of insulation between the first conductive end 414 and the second conductive end 421 when the battery cell 10 is working normally. By providing a conductive movable element 90, when the battery cell 10 experiences thermal runaway, the conductive movable element 90 passes through the first conductive end 414 and the insulating element 45 and contacts the second conductive end 421, so that the first conductive end 414 and the second conductive end 421 form an electrical connection through the conductive movable element 90, realizing an internal short circuit between the positive electrode tab 31 and the negative electrode tab 32, and quickly releasing the energy of the battery cell 10.
[0052] Specifically, the insulating element 45 can be made of a material with insulating properties, such as plastic, ceramic, paraffin, etc., which has good insulation effect.
[0053] The conductive moving part 90 can be made of a conductive material, such as copper or iron, so that the conductive moving part 90 has both good conductivity and high hardness, making it easy to pass through the first conductive end 414 and the insulating part 45.
[0054] Of course, the drive assembly 80 also includes a drive source for driving the conductive movable part 90 to move. Under the action of the drive source, the conductive movable part 90 passes through the first conductive end 414 and the insulating part 45.
[0055] Optionally, such as Figure 4 As shown, the first conductive end 414 is provided with a first through hole 411, and the insulating member 45 is provided with a second through hole 451. The first through hole 411 and the second through hole 451 are connected to form a channel. The conductive movable member 90 is correspondingly provided with the first through hole 411. When the battery cell 10 experiences thermal runaway, the conductive movable member 90 can pass through the channel. The conductive movable member 90 is electrically connected to the first conductive end 414 and the second conductive end 421 respectively.
[0056] In this embodiment, by providing a first through hole 411 in the first conductive end 414 and a second through hole 451 in the insulating member 45, the first through hole 411 and the second through hole 451 are connected to form a channel. The conductive movable member 90 is correspondingly provided with the first through hole 411. The conductive movable member 90 moves along the channel without piercing the solid parts of the first conductive end 414 and the insulating member 45, which can reduce the difficulty of the conductive movable member 90 passing through the first conductive end 414 and the insulating member 45, reduce the driving force required for the conductive movable member 90, and the driving source can be a small driving source, reducing the manufacturing cost.
[0057] Specifically, such as Figure 4 As shown, the first through hole 411 and the second through hole 451 are aligned to form a channel, and the conductive movable member 90 is correspondingly disposed with respect to the first through hole 411. When the battery cell 10 is operating normally, the conductive movable member 90 remains stationary, and the first conductive end 414 and the second conductive end 421 are insulated. When the battery cell 10 experiences thermal runaway, the conductive movable member 90 moves along the channel under the action of a driving source, and the conductive movable member 90 comes into contact with both the first conductive end 414 and the second conductive end 421, thereby achieving electrical connection between the first conductive end 414 and the second conductive end 421.
[0058] It should be noted that, in order to ensure a good electrical connection between the first conductive end 414 and the second conductive end 421, the diameter of the first through hole 411 should be smaller than the diameter of the conductive movable part 90. In this way, after the conductive movable part 90 passes through the first conductive end 414, the conductive movable part 90 and the first through hole 411 are in an interference fit, so that the conductive movable part 90 and the hole wall of the first through hole 411 are in good contact, that is, the conductive movable part 90 and the first conductive end 414 are in good contact.
[0059] Optionally, such as Figure 5 As shown, the conductive movable member 90 has a conductive tip 91, which is positioned toward the first conductive end 414. When the battery cell 10 experiences thermal runaway, the conductive tip 91 can pierce the first conductive end 414 and the insulating member 45, and electrically connect the conductive movable member 90 to the first conductive end 414 and the second conductive end 421.
[0060] In this embodiment, by forming a conductive tip 91 at one end of the conductive movable member 90 facing the first conductive end 414, the conductive tip 91 has good piercing ability. Under the action of the driving source, it can quickly and effectively pierce the first conductive end 414 and the insulating member 45, and penetrate the second conductive end 421, thereby achieving a good electrical connection between the first conductive end 414 and the second conductive end 421.
[0061] Specifically, such as Figure 5 As shown, the conductive tip 91 can be conical, pyramidal, or other shapes, thus forming a sharp conductive tip 91. The structure is simple and easy to manufacture. Moreover, the conductive tip 91 does not depend on the aforementioned channel arrangement and can directly pierce the solid portion of the first conductive end 414 and the insulating member 45.
[0062] It is understandable that both the first conductive end 414 and the insulating element 45 can be made into sheet-like structures to facilitate piercing by the conductive tip 91.
[0063] Optionally, such as Figure 5 As shown, the first conductive end 414 is provided with a first thinning region 412, which is correspondingly provided with the conductive tip 91.
[0064] In this embodiment of the application, by providing a first thinning region 412 at the first conductive end 414, and the first thinning region 412 being provided corresponding to the conductive tip 91, the thickness of the first conductive end 414 at the position corresponding to the first thinning region 412 is reduced, thereby reducing the thickness of the solid portion pierced by the conductive tip 91 and reducing the difficulty of piercing.
[0065] Specifically, the ratio of the depth of the first thinning region 412 to the thickness of the first conductive end 414 can be any value or a range between any two values from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9. It can be flexibly set according to the actual situation, and the embodiments of this application do not limit it.
[0066] It is understandable that the first thinning region 412 is only formed by a localized recess in the first conductive end 414; for example, the diameter of the first thinning region 412 is slightly smaller than the diameter of the conductive moving part 90. Thus, the first thinning region 412 is limited to a localized area and does not affect the overall mechanical strength and current carrying capacity of the first conductive end 414. During normal operation, the first conductive end 414 can still maintain structural integrity and conductivity.
[0067] In addition, such as Figure 5 As shown, the insulating member 45 may be provided with a second thinning region 452, which can be set with reference to the first thinning region 412 of the first conductive end 414, and will not be described in detail here.
[0068] Optionally, such as Figure 3 As shown, the drive assembly 80 also includes a first elastic member 81 and a locking member 82. The first elastic member 81 is connected between the insulating shell 43 and the conductive movable member 90. The locking member 82 is used to lock the first elastic member 81 in a deformed state. When the cell 10 experiences thermal runaway, the locking member 82 releases the locking of the first elastic member 81, so that the first elastic member 81 can change from a deformed state to a free state, thereby driving the conductive movable member 90 to pass through the first conductive end 414 and the insulating member 45 and contact the second conductive end 421.
[0069] In this embodiment, a first elastic element 81 is used as a driving source. After deformation, the first elastic element 81 possesses elastic potential energy. The locking element 82 locks the first elastic element 81 in the deformed state, thereby storing the elastic potential energy, i.e., storing energy in the first elastic element 81. When thermal runaway occurs in the battery cell 10, the locking element 82 fails, releasing the locking of the first elastic element 81. The first elastic element 81 can then transition from the deformed state to a free state, releasing the stored elastic potential energy. The first elastic element 81 drives the conductive movable element 90 to move, causing the conductive movable element 90 to pass through the first conductive end 414 and the insulating element 45 and contact the second conductive end 421, thus achieving an electrical connection between the first conductive end 414 and the second conductive end 421 through the conductive movable element 90.
[0070] Specifically, the first elastic element 81 can be a compression spring, capable of deformation and storing elastic potential energy. The locking element 82 locks the deformed first elastic element 81, preventing it from rebounding and storing elastic potential energy. It also ensures that when the battery cell 10 is operating normally, the conductive moving part 90 will not establish an electrical connection between the first conductive end 414 and the second conductive end 421. When the locking element 82 fails, the stored elastic potential energy is released instantaneously (on the millisecond scale), converting into enormous kinetic energy in the conductive moving part 90, driving it to pierce the first conductive end 414 and the insulating part 45.
[0071] Optionally, the first elastic element 81 is made of shape memory alloy.
[0072] In this embodiment, by making the first elastic element 81 a shape memory alloy, the first elastic element 81 deforms at low temperatures, thereby storing elastic potential energy. During thermal runaway, as the temperature rises, the first elastic element 81 recovers its deformation, releasing the stored elastic potential energy.
[0073] Specifically, shape memory alloys (SMA) are alloy materials that can completely eliminate the deformation that occurred at a lower temperature after being heated and restore their original shape before deformation, i.e., alloys with a "memory" effect.
[0074] In some embodiments, the first elastic element 81 may be made of one of nickel-titanium shape memory alloy (Ni-TiSMA), copper-based shape memory alloy (CuSMA), or iron-based shape memory alloy (FeSMA).
[0075] Optionally, the locking member 82 is a hot-melt material layer, which covers the outer peripheral surface of the first elastic member 81.
[0076] In this embodiment, by covering the outer periphery of the first elastic member 81 with a layer of hot-melt material, the first elastic member 81 can be locked, keeping it firmly in a deformed state. When the battery cell 10 experiences thermal runaway, the temperature inside the cell 10 rises sharply. When the temperature reaches the melting point of the locking member 82, the locking member 82 melts and fails, losing its locking ability on the first elastic member 81. The first elastic member 81 then moves, causing the conductive moving member 90 to move. Furthermore, the locking member 82 is a layer of hot-melt material, achieving locking by covering the outer periphery of the first elastic member 81, eliminating the need for complex mechanical latches or electromagnetic mechanisms, resulting in a simple structure and low cost.
[0077] Specifically, the hot-melt material layer can be made of low-melting-point alloys, low-melting-point plastics, or paraffin wax, etc.
[0078] In some embodiments, a material with a melting point slightly higher than the upper limit of the normal operating temperature of the battery cell 10 but significantly lower than the thermal runaway temperature can be selected to make the thermally fusible material layer. In this way, the locking member 82 can be melted by the high temperature of thermal runaway of the battery cell 10 itself, or it can be rapidly heated to the melting point temperature by a small heating element, providing a flexible way to release the locking.
[0079] Optionally, such as Figure 2 As shown, the battery pack also includes a control module 65 and a heating element 50. The heating element 50 is connected to the locking element 82 and is electrically connected to the control module 65. The control module 65 is used to control the heating element 50 to heat the locking element 82 when thermal runaway occurs in the battery cell 10.
[0080] In this embodiment, by setting a heating element 50 connected to a locking element 82, and electrically connecting the heating element 50 to the control module 65, when the control module 65 detects thermal runaway of the battery cell 10, it can actively control the heating element 50 to start, thereby heating the heating element 50, melting the locking element 82, releasing the locking of the first elastic element 81, and causing the first elastic element 81 to drive the conductive moving element 90 to move, thereby realizing the electrical connection between the first conductive end 414 and the second conductive end 421, realizing an internal short circuit, and realizing the rapid release of energy of the battery cell 10.
[0081] It should be noted that by setting up the control module 65 and the heating element 50, the heating element 50 can be actively activated when thermal runaway of the battery cell 10 is detected, instead of waiting for the heat from thermal runaway to be transferred to the insulating shell 43, thereby melting the locking element 82 before releasing the first elastic element 81. For example, in some cases, the battery cell 10 has already begun to react violently, but it takes time for the heat to reach the position of the locking element 82. By actively activating the heating element 50 through the control module 65, this time difference is eliminated, ensuring that the melting of the locking element 82 occurs basically synchronously with the thermal runaway inside the battery cell 10.
[0082] This method of cooperating between the control module 65 and the heating element 50 can achieve the melting of the locking element 82 earlier than simply waiting for the temperature to reach the melting point of the locking element 82, thereby achieving the electrical connection between the first conductive terminal 414 and the second conductive terminal 421 earlier and releasing the energy of the battery cell 10 earlier. Once thermal runaway of the battery cell 10 is detected, the control module 65 immediately controls the heating element 50 to be energized, heating the locking element 82 to the melting point in a very short time (e.g., tens of milliseconds), thereby achieving the melting of the locking element 82.
[0083] For example, taking temperature detection as an example, the upper limit of the normal operating temperature of the battery cell 10 is about 60°C, and the temperature at which thermal runaway occurs exceeds 100°C. When the control module 65 detects that the temperature of the battery cell 10 exceeds the upper limit of the normal operating temperature, for example, the detected temperature is 70°C, it is determined that the battery cell 10 is in the early stage of thermal runaway. The heating element 50 is then activated to heat the locking element 82 to the melting point, thereby melting the locking element 82.
[0084] In summary, this method can release the energy of cell 10 in advance. In the early stage of thermal runaway (before cell 10 fully explodes), the energy of cell 10 is released through the internal short circuit between the positive tab 31 and the negative tab 32, which is more effective in preventing the spread of thermal runaway.
[0085] It should be noted that the control module 65 can detect and judge the thermal runaway of the battery cell 10 by detecting various signals such as temperature, voltage, temperature rise rate, voltage drop rate, gas generation signal and impedance change inside the battery cell 10.
[0086] Optionally, such as Figure 6 As shown, the internal short-circuit device 40 also includes a heat-fused insulating layer 46, which is disposed in the insulating gap 47 and connected to at least one of the first conductive end 414 and the second conductive end 421. The drive assembly 80 includes a second elastic member 83, one end of which is connected to the insulating shell 43, and the other end of which abuts against the first conductive end 414, so that the second elastic member 83 is in a deformed state. When the cell 10 experiences thermal runaway, the heat-fused insulating layer 46 can melt, and the second elastic member 83 changes from the deformed state to the free state, thereby driving the first conductive end 414 to approach the second conductive end 421 and connect it to the second conductive end 421 electrically.
[0087] In this embodiment, by providing a heat-fused insulating layer 46 in the insulating gap 47, the heat-fused insulating layer 46 is solid at low temperatures, which can achieve insulation between the first conductive end 414 and the second conductive end 421, and at the same time support the first conductive end 414, so that the second elastic member 83 is compressed between the insulating shell 43 and the first conductive end 414, thereby storing elastic potential energy in the second elastic member 83. When the battery cell 10 experiences thermal runaway, the heat-fused insulating layer 46 melts and no longer supports the first conductive end 414. Under the action of the second elastic member 83, the first conductive end 414 moves towards the second conductive end 421 and becomes electrically connected to the second conductive end 421, thereby achieving an internal short circuit between the positive electrode tab 31 and the negative electrode tab 32, and rapidly releasing the energy of the battery cell 10.
[0088] Specifically, the second elastic element 83 can be a compression spring, capable of deformation and storing elastic potential energy. The hot-melt insulating layer 46 can be made of low-melting-point alloys, low-melting-point plastics, or paraffin wax, etc.
[0089] Optionally, such as Figure 2 As shown, the battery pack also includes a control module 65 and a heating element 50. The heating element 50 is connected to the hot melt insulation layer 46 and is electrically connected to the control module 65. The control module 65 is used to control the heating element 50 to heat the hot melt insulation layer 46 when the cell 10 experiences thermal runaway.
[0090] In this embodiment, a heating element 50 is connected to a heat-melting insulating layer 46. The heating element 50 is electrically connected to a control module 65. When the control module 65 detects thermal runaway in the battery cell 10, it can actively control the heating element 50 to start, thereby heating the heating element 50 and melting the heat-melting insulating layer 46. The heating element 50 no longer supports the first conductive end 414, causing the second elastic element 83 to drive the conductive movable element 90 to move, thereby achieving electrical connection between the first conductive end 414 and the second conductive end 421, realizing an internal short circuit, and enabling rapid release of energy from the battery cell 10.
[0091] It should be noted that by setting up the control module 65 and the heating element 50, the heating element 50 can be actively activated when thermal runaway of the battery cell 10 is detected, instead of waiting for the heat from thermal runaway to be transferred to the insulating shell 43 and thus melt the heat-fused insulating layer 46 before the second elastic element 83 can be driven. For example, in some cases, the battery cell 10 has already begun to react violently, but it takes time for the heat to reach the heat-fused insulating layer 46. By actively activating the heating element 50 through the control module 65, this time difference is eliminated, ensuring that the melting of the heat-fused insulating layer 46 occurs basically synchronously with the thermal runaway inside the battery cell 10.
[0092] This combination of control module 65 and heating element 50 allows the thermal insulation layer 46 to melt earlier than simply waiting for the temperature to reach its melting point. This enables earlier electrical connection between the first conductive terminal 414 and the second conductive terminal 421, and earlier release of energy from the battery cell 10. Once thermal runaway is detected in the battery cell 10, control module 65 immediately energizes heating element 50, heating the thermal insulation layer 46 to its melting point within a very short time (e.g., tens of milliseconds), thus melting the thermal insulation layer 46.
[0093] For example, taking temperature detection as an example, the upper limit of the normal operating temperature of the battery cell 10 is about 60°C, and the temperature at which thermal runaway occurs exceeds 100°C. When the control module 65 detects that the temperature of the battery cell 10 exceeds the upper limit of the normal operating temperature, for example, the detected temperature is 70°C, it is determined that the battery cell 10 is in the early stage of thermal runaway. The heating element 50 is then activated to heat the hot melt insulation layer 46 to the melting point, thereby melting the hot melt insulation layer 46.
[0094] In summary, this method can release the energy of cell 10 in advance. In the early stage of thermal runaway (before cell 10 fully explodes), the energy of cell 10 is released through the internal short circuit between the positive tab 31 and the negative tab 32, which is more effective in preventing the spread of thermal runaway.
[0095] Optionally, such as Figure 7 and Figure 8 As shown, the first conductive end 414 has a plurality of conductive protrusions 413 on the side facing the second conductive end 421, and the hot melt insulating layer 46 is at least disposed between the conductive protrusions 413 and the second conductive end 421. The plurality of conductive protrusions 413 are arranged at intervals, and a gap is formed between two adjacent conductive protrusions 413. The heating element 50 includes a heating part 51, which is disposed in the gap.
[0096] In this embodiment, by providing a heat-melting insulating layer 46 at least between the conductive protrusion 413 and the second conductive end 421, insulation between the first conductive end 414 and the second conductive end 421 can be achieved. By placing the heating part 51 of the heating element 50 between two adjacent conductive protrusions 413, heating of the heat-melting insulating layer 46 can be achieved more quickly. Moreover, when the first conductive end 414 moves towards the second conductive end 421, the conductive protrusion 413 will not press against the heating part 51, making it easier to achieve contact between the conductive protrusion 413 and the second conductive end 421, thereby making it easier to achieve electrical connection between the first conductive end 414 and the second conductive end 421. At the same time, multiple conductive protrusions 413 can also form a redundant design, forming a multi-point contact structure. Even if some conductive protrusions 413 have poor contact, other conductive protrusions 413 can still ensure a low-impedance path.
[0097] Specifically, such as Figure 7 As shown, multiple conductive protrusions 413 are arranged at intervals, and the heating part 51 of the heating element 50 can be formed in a serpentine shape to match the gaps between the multiple conductive protrusions 413.
[0098] Optionally, such as Figure 2 As shown, the control module 65 includes a control unit 60 and a sensor 70. The sensor 70 is electrically connected to the control unit 60. The sensor 70 is used to sense the working state of the battery cell 10, and the control unit 60 is used to control the operation of the heating element 50 based on the sensing result of the sensor 70.
[0099] In this embodiment, by setting the sensing element 70, the working state of the battery cell 10 can be sensed, thereby realizing the detection of the battery cell 10. The control unit 60 can control the operation of the heating element 50 based on the sensing result of the sensing element 70. For example, if the sensing element 70 detects that the battery cell 10 has thermal runaway, the control unit 60 can control the heating element 50 to start.
[0100] Specifically, the sensing element 70 can be a temperature sensor to sense the temperature and temperature rise rate within the battery cell 10; the sensing element 70 can be a voltage sensor to sense the voltage and voltage drop rate within the battery cell 10; the sensing element 70 can be a gas sensor to sense the gas content within the battery cell 10. The specific type of the sensing element 70 can be flexibly set according to actual conditions, and this application embodiment does not limit it.
[0101] In some embodiments, the sensing element 70 may be one or more of the types described above, and may be disposed in multiple locations to form a form in which multiple sensing elements 70 sense together. The cooperation of multiple sensing elements 70 can improve the accuracy and lead time of thermal runaway determination, and reduce false triggering and missed triggering.
[0102] Optionally, embodiments of this application provide an electrical device including the battery pack of any of the above embodiments.
[0103] In this embodiment of the application, since the electrical device includes the battery pack of any of the above embodiments, it has the beneficial effect of the battery pack, that is, it can quickly release the energy of the cell 10 in a short time, reduce the energy in the cell 10, reduce the possibility of the cell 10 having a safety accident, and thus improve the safety of the entire battery pack.
[0104] In some embodiments, electrical devices may include laptops, pen-based computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.
[0105] Specifically, the vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.
[0106] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0107] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.
Claims
1. A battery pack, characterized by, The battery cell (10) includes a housing (20), an electrode assembly (30), and an internal short-circuit device (40). The electrode assembly (30) is disposed inside the housing (20), and one side of the electrode assembly (30) has a positive electrode tab (31) and a negative electrode tab (32). The internal short-circuit device (40) includes a first conductive element (41), a second conductive element (42), and a drive assembly (80). The first conductive element (41) is electrically connected to the positive electrode (31), and the second conductive element (42) is electrically connected to the negative electrode (32). The first conductive element (41) has a first conductive end (414) away from the positive electrode (31), and the second conductive element (42) has a second conductive end (421) away from the negative electrode (32). The first conductive end (414) and the second conductive end (421) are opposite to each other, and there is an insulating gap (47) between them to achieve mutual insulation. The drive assembly (80) is located on the side of the first conductive end (414) away from the second conductive end (421). When the cell (10) experiences thermal runaway, the drive assembly (80) is at least partially able to move in response to thermal runaway so that the first conductive end (414) and the second conductive end (421) are electrically connected.
2. The battery pack of claim 1, wherein, The internal short-circuit device (40) further includes an insulating shell (43), which is disposed inside and connected to the housing (20). The insulating shell (43) has a mounting cavity (44). The first conductive end (414) and the second conductive end (421) pass through the insulating shell (43) and extend into the mounting cavity (44). The driving assembly (80) is disposed inside the mounting cavity (44) and connected to the insulating shell (43).
3. The battery pack according to claim 2, characterized in that, The internal short-circuit device (40) further includes an insulating element (45), which is disposed in the insulating gap (47) and is connected to at least one of the first conductive end (414) and the second conductive end (421). The drive assembly (80) includes a conductive movable element (90) located on the side of the first conductive end (414) away from the second conductive end (421). When thermal runaway occurs in the cell (10), the conductive movable part (90) can pass through the first conductive end (414) and the insulating part (45) and contact the second conductive end (421), and the first conductive end (414) and the second conductive end (421) are electrically connected through the conductive movable part (90).
4. The battery pack according to claim 3, characterized in that, The first conductive end (414) is provided with a first through hole (411), and the insulating member (45) is provided with a second through hole (451). The first through hole (411) and the second through hole (451) are connected to form a channel, and the conductive movable member (90) is provided correspondingly to the first through hole (411). When thermal runaway occurs in the cell (10), the conductive movable element (90) can pass through the channel, and the conductive movable element (90) is electrically connected to the first conductive end (414) and the second conductive end (421) respectively.
5. The battery pack according to claim 3, characterized in that, The conductive movable part (90) has a conductive tip (91) which is disposed toward the first conductive end (414); When thermal runaway occurs in the cell (10), the conductive tip (91) can pierce the first conductive end (414) and the insulating member (45), and make the conductive movable member (90) electrically connected to the first conductive end (414) and the second conductive end (421).
6. The battery pack according to claim 5, characterized in that, The first conductive end (414) is provided with a first thinning region (412), and the first thinning region (412) is correspondingly provided with the conductive tip (91).
7. The battery pack according to claim 3, characterized in that, The drive assembly (80) further includes a first elastic element (81) and a locking element (82). The first elastic element (81) is connected between the insulating shell (43) and the conductive moving part (90). The locking element (82) is used to lock the first elastic element (81) in a deformed state. When thermal runaway occurs in the cell (10), the locking member (82) releases the locking of the first elastic member (81) so that the first elastic member (81) can change from a deformed state to a free state, thereby driving the conductive moving member (90) to pass through the first conductive end (414) and the insulating member (45) and to contact the second conductive end (421).
8. The battery pack according to claim 7, characterized in that, The first elastic element (81) is made of shape memory alloy.
9. The battery pack according to claim 7, characterized in that, The locking element (82) is a hot melt material layer, which covers the outer peripheral surface of the first elastic element (81).
10. The battery pack according to claim 9, characterized in that, The battery pack also includes a control module (65) and a heating element (50). The heating element (50) is connected to the locking element (82). The heating element (50) is electrically connected to the control module (65). The control module (65) is used to control the heating element (50) to heat the locking element (82) when the battery cell (10) experiences thermal runaway.
11. The battery pack according to claim 2, characterized in that, The internal short-circuit device (40) further includes a hot-melt insulating layer (46), which is disposed in the insulating gap (47) and is connected to at least one of the first conductive end (414) and the second conductive end (421). The drive assembly (80) includes a second elastic element (83), one end of which is connected to the insulating shell (43), and the other end of which abuts against the first conductive end (414) so that the second elastic element (83) is in a deformed state. When thermal runaway occurs in the battery cell (10), the heat-melting insulation layer (46) can melt, and the second elastic element (83) changes from a deformed state to a free state, so as to drive the first conductive end (414) to approach the second conductive end (421) and connect with the second conductive end (421).
12. The battery pack according to claim 11, characterized in that, The battery pack also includes a control module (65) and a heating element (50). The heating element (50) is connected to the hot melt insulation layer (46) and is electrically connected to the control module (65). The control module (65) is used to control the heating element (50) to heat the hot melt insulation layer (46) when the battery cell (10) experiences thermal runaway.
13. The battery pack according to claim 12, characterized in that, The first conductive end (414) has a plurality of conductive protrusions (413) on the side facing the second conductive end (421). The hot melt insulating layer (46) is at least disposed between the conductive protrusions (413) and the second conductive end (421). The plurality of conductive protrusions (413) are arranged at intervals, and a gap is formed between two adjacent conductive protrusions (413). The heating element (50) includes a heating part (51), and the heating part (51) is disposed in the gap.
14. The battery pack according to claim 10 or 12, characterized in that, The control module (65) includes a control unit (60) and a sensor (70). The sensor (70) is electrically connected to the control unit (60). The sensor (70) is used to sense the working state of the battery cell (10). The control unit (60) is used to control the operation of the heating element (50) based on the sensing result of the sensor (70).
15. An electrical appliance, characterized in that, Includes the battery pack as described in any one of claims 1-14.