Battery cell, battery device, and energy storage device

Abstract

The application discloses a battery monomer, a battery device and an energy storage device, and relates to the technical field of batteries, wherein the battery monomer comprises a main shell and at least one end cover; the main shell is provided with a containing cavity, the containing cavity is provided with an electrode assembly, and the containing cavity is formed with an opening; the at least one end cover is arranged on the opening of the containing cavity, the at least one end cover is provided with two electrode terminals, the two electrode terminals are electrically connected to the positive electrode tab and the negative electrode tab of the electrode assembly respectively; wherein a heat-triggered conductive piece is arranged between the two electrode terminals, the heat-triggered conductive piece is configured to have different resistance values in at least two temperature ranges, and according to the resistance value change characteristic, the heat-triggered conductive piece can provide a current-limiting conductive path for the two electrode terminals when the battery monomer is in thermal runaway, the electric energy in the electrode assembly can be slowly released through the heat-triggered conductive piece, the risk of arc striking of the battery monomer is reduced, and the risk of deflagration of the battery monomer is reduced.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an energy storage device. Background Technology

[0002] The thermal runaway process of a large-capacity energy storage battery cell typically includes a triggering phase, a high-temperature exothermic phase, and an eruption phase. During the high-temperature exothermic phase of thermal runaway, the electrode materials inside the battery cell decompose to release oxygen, and the electrolyte decomposes violently, producing a large amount of flammable gases, mainly hydrogen, carbon monoxide, and hydrocarbons. These flammable gases are easily ignited, leading to deflagration of the battery cell. Summary of the Invention

[0003] The main purpose of this application is to propose a battery cell, battery device, and energy storage device, which aims to improve the current situation where the risk of deflagration in battery cells during thermal runaway is relatively high.

[0004] Firstly, the battery cell proposed in this application includes: The main housing has a receiving cavity in which an electrode assembly is disposed, and the receiving cavity has an opening; and At least one end cap is provided on the opening of the receiving cavity, and the at least one end cap is provided with two electrode terminals, which are respectively electrically connected to the positive electrode and the negative electrode of the electrode assembly; A thermally triggered conductive element is provided between the two electrode terminals, and the thermally triggered conductive element is configured to have different resistance values ​​in at least two temperature ranges.

[0005] In some embodiments, the thermally triggered conductive element is configured such that its resistance in the first temperature range is greater than its resistance in the second temperature range. The first temperature range is lower than the second temperature range.

[0006] In some embodiments, the thermally triggered conductive element includes: An insulating body is disposed on the end cap; and, Multiple conductive particles are disposed on the insulating body, with adjacent conductive particles being independently disposed, and the multiple conductive particles are configured to be able to melt upon heating and form a conductive phase.

[0007] In some embodiments, the interior of the insulating body has a microporous structure, and the plurality of conductive particles are embedded in the microporous structure of the insulating body.

[0008] In some embodiments, the thermally triggered conductive element further includes an adhesive bonded between the insulating body and the conductive particles; and / or, The insulating body is made of at least one of ceramic fibers and ceramic particles.

[0009] In some embodiments, the melting point of the conductive particles is between 250°C and 300°C; and / or, The conductive particles are made of bismuth-based alloys or tin-based alloys.

[0010] In some embodiments, the thermally triggered conductive element is connected to the two electrode terminals.

[0011] In some embodiments, one end cap is provided, the end cap having a metal body, the thermally triggered conductive element covering the side of the metal body facing the electrode assembly and isolating the metal body from the electrode assembly; The two electrode terminals are respectively inserted into and connected to the thermally triggered conductive element.

[0012] In some embodiments, the electrode terminals include: The electrode post is inserted through the thermally triggered conductive element; and, An inner connector is disposed at the inner end of the electrode post, the inner connector is connected to the tab of the electrode assembly, and abuts against the thermally triggered conductive element.

[0013] In some embodiments, the end cap has a metal body; An electrical connector is provided between the two electrode terminals and the corresponding metal body, and at least one of the electrical connectors is configured as the thermally triggered conductive element.

[0014] In some embodiments, one of the electrical connectors is configured as the thermally triggered conductive element, and the other electrical connector is configured as an equipotential connector; The equipotential bonding member is disposed between the electrode terminal corresponding to the positive electrode tab and the metal body; The thermally triggered conductive element is disposed between the electrode terminal corresponding to the negative electrode tab and the metal body.

[0015] In some embodiments, the thermally triggered conductive element is disposed at the end of the end cap opposite to the electrode assembly; The electrode terminals include: The electrode post is inserted through the thermally triggered conductive element; and, An external connector is disposed at the outer end of the pole post, and the external connector abuts against the thermally triggered conductive element.

[0016] In some embodiments, the electrode terminals include: The pole post passes through the mounting hole in the metal body; and, A sealing ring is fitted onto the pole post and abuts against the metal body, with at least a portion of the sealing ring located between the inner wall of the mounting hole and the pole post; The sealing ring includes the thermally triggered conductive element.

[0017] In some embodiments, the sealing ring includes: A sealing body, elastically configured, is disposed between the inner wall of the mounting hole and the pole post; and, A limiting protrusion is connected to one end of the sealing body facing the electrode assembly, and the limiting protrusion abuts against the metal body; The limiting protrusion includes the thermally triggered conductive element.

[0018] In some embodiments, the thermally triggered conductive element is configured as a negative temperature coefficient thermistor; and / or, The thermally triggered conductive component is provided with a phase change heat absorption structure.

[0019] Secondly, the battery device provided in this application includes the aforementioned battery cell.

[0020] Thirdly, the energy storage device provided in this application includes the aforementioned battery device.

[0021] In the technical solution provided in this application, the thermally triggered conductive element is configured to have different resistance values ​​in at least two temperature ranges. Based on this resistance-preventing characteristic, the thermally triggered conductive element has little impact on the battery cell during normal charging and discharging. The thermally triggered conductive element can actively provide a current-limiting conductive path for the two electrode terminals when the battery cell experiences thermal runaway. The electrical energy inside the electrode assembly can be slowly released through the thermally triggered conductive element, reducing the risk of arcing and sparking in the battery cell, which in turn reduces the risk of deflagration in the battery cell. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 An exploded structural diagram of an embodiment of the battery cell provided in this application; Figure 2 An exploded structural diagram of the first embodiment of the end cap of the battery cell provided in this application; Figure 3An exploded structural diagram of the second embodiment of the end cap of the battery cell provided in this application; Figure 4 An exploded view of the third embodiment of the end cap of the battery cell provided in this application; Figure 5 for Figure 4 Schematic diagram of the middle sealing ring; Figure 6 A schematic diagram of the microstructure of a thermally triggered conductive element in a battery cell provided in this application; Figure 7 An exploded structural diagram of an embodiment of the battery device provided in this application; Figure 8 This is a schematic diagram of an embodiment of the energy storage device provided in this application.

[0024] Explanation of icon numbers: 10000, Energy storage devices; 1000. Battery unit; 2000. Energy storage cabinet; 100. Battery cell; 200. Casing; 210. Casing body; 220. Casing cover; 1. Main housing; 11. Receiving cavity; 12. Electrode assembly; 121. Positive electrode tab; 122. Negative electrode tab; 123. Electrode body; 2. End cap; 21. Electrode terminal; 211. Electrode post; 212. Inner connector; 213. Outer connector; 22. Metal body; 221. Mounting holes; 23. Sealing ring; 231. Sealing body; 232. Limiting protrusion; 24. Inner insulating component; 25. Outer insulating component; 3. Electrical connectors; 31. Thermally triggered conductive components; 311. Insulating body; 3111. Microporous structure; 312. Conductive particles; 32. Equipotential connectors.

[0025] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] It should be noted that if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0028] The thermal runaway process of a large-capacity energy storage battery cell typically includes a triggering phase, a high-temperature exothermic phase, and an eruption phase. During the high-temperature exothermic phase of thermal runaway, the electrode materials inside the battery cell decompose to release oxygen, and the electrolyte undergoes violent decomposition, producing a large amount of flammable gas, primarily hydrogen, carbon monoxide, and hydrocarbons. Simultaneously, the electrode components of the battery cell may still retain residual high voltage (tens to hundreds of volts). At this point, molten aluminum, carbide deposits, and electrolyte decomposition products can randomly form unstable and uncontrollable abnormal conductive paths between the electrodes and the casing. When this residual high voltage is applied to the tiny gaps or weak points in the insulation of these abnormal conductive paths, it can easily trigger electric field breakdown and arcing, which can then ignite the internal flammable gas, leading to a fire or explosion.

[0029] Analysis shows that actively eliminating the residual high voltage in the electrode assembly when a battery cell experiences thermal runaway can reduce the risk of electric field breakdown and arcing within the cell. However, existing methods such as pressure relief with explosion-proof valves, fuse blowing, and external power disconnection of the battery management system (BMS) cannot eliminate the residual high voltage inside the battery cell. Therefore, there is an urgent need in the field to construct a structure inside the cell that can actively and controllably reduce the residual voltage during thermal runaway, thereby fundamentally reducing the difficulty of triggering electric field breakdown and arcing.

[0030] In view of this, this application provides a battery cell, a battery device, and an energy storage device, which can at least improve the current situation where the risk of deflagration in battery cells during thermal runaway is relatively high.

[0031] To facilitate understanding of the battery cell provided in this application, the following description is provided in conjunction with the accompanying drawings, wherein... Figure 1 An exploded structural diagram of an embodiment of the battery cell provided in this application; Figure 2 An exploded structural diagram of the first embodiment of the end cap of the battery cell provided in this application; Figure 3An exploded structural diagram of the second embodiment of the end cap of the battery cell provided in this application; Figure 4 An exploded view of the third embodiment of the end cap of the battery cell provided in this application; Figure 5 for Figure 4 Schematic diagram of the middle sealing ring; Figure 6 This is a schematic diagram of the microstructure of an embodiment of the thermally triggered conductive element in a battery cell provided in this application.

[0032] Please see Figure 1 The structure of a battery cell 100 typically includes a main housing 1, an end cap 2, an electrode assembly 12, and two electrode terminals 21. A receiving cavity 11 is formed within the main housing 1, and the end cap 2 covers the opening of the receiving cavity 11 of the main housing 1 to seal the receiving cavity 11. The electrode assembly 12 is disposed within the receiving cavity 11, and the two electrode terminals 21 penetrate the end cap 2 and are electrically connected to the positive electrode tab 121 and negative electrode tab 122 of the electrode assembly 12 respectively via an adapter. The electrode assembly 12 is the component in the battery cell 100 where the electrochemical reaction occurs. It is mainly formed by a positive electrode sheet and a negative electrode sheet through a winding or stacking process, and a separator is typically provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the electrode body 123 of the electrode assembly 12, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive electrode tab 121 and the negative electrode tab 122 can be located together at one end of the electrode body 123 or at opposite ends of the body. When the positive electrode tab 121 and the negative electrode tab 122 are located at one end of the electrode body 123, one end cap 2 is usually provided corresponding to the position of the positive electrode tab 121 and the negative electrode tab 122, and two electrode terminals 21 are respectively provided on the end cap 2. When the positive electrode tab 121 and the negative electrode tab 122 are located at opposite ends of the electrode body 123, two end caps 2 are usually provided, respectively corresponding to the positions of the positive electrode tab 121 and the negative electrode tab 122, and two electrode terminals 21 are respectively provided on the two end caps 2. During the charging and discharging process of the battery, the positive electrode active material and the negative electrode active material react through the electrolyte filled in the main casing 1.

[0033] Firstly, please refer to Figure 1 and Figure 2 The battery cell 100 provided in this application includes a main housing 1 and at least one end cap 2; the main housing 1 has a receiving cavity 11, an electrode assembly 12 is disposed in the receiving cavity 11, and the receiving cavity 11 has an opening; at least one end cap 2 is disposed on the opening of the receiving cavity 11, and at least one end cap 2 is provided with two electrode terminals 21, the two electrode terminals 21 being electrically connected to the positive electrode tab 121 and the negative electrode tab 122 of the electrode assembly 12 respectively; wherein, a thermally triggered conductive element 31 is disposed between the two electrode terminals 21, and the thermally triggered conductive element 31 is configured to have different resistance values ​​in at least two temperature ranges.

[0034] It should be noted that the battery cell 100 provided in this application includes, but is not limited to, power battery cell 100 and energy storage battery cell 100, wherein the capacity of the large-capacity energy storage battery cell 100 typically exceeds 200Ah.

[0035] The main housing 1 can have one or two openings in the receiving cavity 11. When the receiving cavity 11 has only one opening, one end cover 2 is provided accordingly. At this time, both electrode terminals 21 are provided on the end cover 2. When the receiving cavity 11 has two openings, two end covers 2 are provided accordingly, and the two end covers 2 are respectively provided on the two openings of the receiving cavity 11.

[0036] The phrase "a thermally triggered conductive element 31 is provided between the two electrode terminals 21" can be understood as indicating a continuous connection structure between the two electrode terminals 21. The thermally triggered conductive element 31 can be part of this connection structure. For example, when the two electrode terminals 21 are located on the same end cap 2, the end cap 2 can also form part of the connection structure. Of course, the thermally triggered conductive element 31 can also serve as the entire connection structure. The two electrode terminals 21 can be divided into a positive terminal and a negative terminal. The positive terminal is connected to the positive electrode tab 121 of the electrode assembly 12, and the negative terminal is connected to the negative electrode tab 122 of the electrode assembly 12.

[0037] Regarding the statement that "the thermal triggering conductive element 31 is configured to have different resistance values ​​in at least two temperature ranges," the resistance value of the thermal triggering conductive element 31 is not constant, but can change with temperature variations within a specific range. When the thermal triggering conductive element is placed between the two electrode terminals, its impact on the battery cell 100 during normal charging and discharging is minimal. However, in the event of thermal runaway of the electrode assembly 12, the thermal triggering conductive element can typically provide a current-limiting conductive path for the two electrode terminals 21. This "current-limiting conductive path" refers to a conductive path where the current magnitude is restricted. This ensures that the conduction between the two electrode terminals 21 is not a short-circuit conduction, but rather a conduction state with a limited current magnitude, slowly releasing the residual electrical energy in the electrode assembly 12 with a safe current ranging from milliamperes to amperes (for example, with a residual voltage of 400V, the discharge current can be controlled between 80mA and 8A with the help of the thermal triggering conductive element 31, far below the dangerous discharge threshold).

[0038] In the technical solution provided in this application, the thermally triggered conductive element 31 is configured to have different resistance values ​​in at least two temperature ranges. Based on this resistance-preventing characteristic, the thermally triggered conductive element 31 has little impact on the battery cell 100 under normal charging and discharging conditions. The thermally triggered conductive element 31 can actively provide a current-limiting conductive path for the two electrode terminals when the battery cell 100 experiences thermal runaway. The electrical energy inside the electrode assembly 12 can be slowly released through the thermally triggered conductive element 31, reducing the risk of arcing and sparking in the battery cell 100, which also reduces the risk of deflagration in the battery cell 100.

[0039] Regarding the statement that "the thermally triggered conductive element 31 is configured to have different resistance values ​​in at least two temperature ranges", in one embodiment, the thermally triggered conductive element 31 is configured to have a greater resistance value in the first temperature range than in the second temperature range; wherein, the first temperature range is lower than the second temperature range.

[0040] When the electrode assembly 12 experiences thermal runaway, the battery cell 100 typically continues to heat up, reaching a temperature that passes through the first temperature range and then the second temperature range. The resistance of the thermally triggered conductive element 31 in the first temperature range is greater than its resistance in the second temperature range. This can be understood as the thermally triggered conductive element 31 being in a high-resistance insulating state in the first temperature range (for example, the resistance of the thermally triggered conductive element 31 in the first temperature range is typically greater than 100MΩ, or even greater than 1GΩ), to prevent short circuits between the two electrode terminals 21. In the second temperature range, the thermally triggered conductive element 31 is in a medium-resistance conductive state (for example, the resistance of the thermally triggered conductive element 31 in the second temperature range can decrease to between 10Ω and 1000Ω, between 50Ω and 5000Ω, or even between 10Ω and 30 kΩ. The range of values ​​for these equal resistance values ​​is usually determined by the capacity of the battery cell. For example, when the capacity of the battery cell is too large, the resistance of the thermally triggered conductive element 31 in the conductive state can be set to be larger), to maintain a current-limited conductive state.

[0041] There are several possibilities regarding the value ranges of the first and second temperature ranges. For example, the first and second temperature ranges can be two adjacent temperature ranges, and the intersection of these two temperature ranges can be understood as the trigger temperature threshold. The "trigger temperature threshold" refers to the critical temperature point at which the thermally triggered conductive element 31 decreases from a high resistance value to a medium resistance value. This trigger temperature threshold can be between 130℃ and 250℃, or between 250℃ and 300℃. Of course, it is also possible that the trigger temperature threshold can be between 300℃ and 500℃, or even between 500℃ and 600℃. The temperature range is specified; in one embodiment, the first temperature range is 0°C to 250°C, and the second temperature range is a temperature range greater than 250°C, specifically 250°C to 500°C. In this case, the trigger temperature threshold is 250°C. It should be understood that as long as the trigger temperature threshold is within the thermal runaway temperature range of the battery cell 100 (typically between 130°C and 600°C), the thermal trigger conductive element 31 can be considered to reduce the resistance and discharge current during the thermal runaway process of the battery cell 100, thereby contributing to reducing the risk of deflagration of the battery cell 100. Of course, it is also possible that the first and second temperature ranges can be two temperature intervals, for example, the first temperature range is 0°C to 200°C, and the second temperature range is greater than 250°C.

[0042] In the above technical solution, the thermally triggered conductive element 31 is in a high-resistance insulating state at room temperature, which can reduce its impact on the charging and discharging of the battery cell 100. When the electrode assembly 12 thermally runs away, the temperature of the battery cell 100 continues to rise, and the thermally triggered conductive element 31 can be heated to transform into a conductive state with a medium resistance value, thereby actively providing a current-limiting conductive path for the two electrode terminals. The residual high voltage inside the electrode assembly 31 can be slowly released through the thermally triggered conductive element 31, reducing the risk of arcing and sparking in the battery cell 100.

[0043] Please see Figure 6 In some embodiments, the heat-triggered conductive element 31 includes an insulating body 311 and a plurality of conductive particles 312; the insulating body 311 is disposed on the end cap 2; the plurality of conductive particles 312 are disposed on the insulating body 311, and two adjacent conductive particles 312 are independently disposed, and the plurality of conductive particles 312 are configured to be able to melt upon heating and form a conductive phase.

[0044] "Conductive particles 312" typically have a melting point. At room temperature, conductive particles 312 are in a solid state and their positions on the insulating body 311 can be fixed, thus keeping adjacent conductive particles 312 independent of each other. When the electrode assembly 12 experiences thermal runaway, the temperature of the battery cell 100 continues to rise. When the temperature of the battery cell 100 reaches the melting point of the conductive particles 312, the conductive particles 312 can melt into liquid droplets. The liquid droplets have strong fluidity, thus forming isolated "conductive islands" or extremely fine "conductive whiskers". These discontinuous conductive nodes are connected in series or in parallel on a macroscopic scale to form a conductive network with a medium resistance value. "Conductive phase" refers to the aforementioned conductive network.

[0045] The above-mentioned technical solution, which uses temperature to trigger the melting of multiple conductive particles 312 to form a conductive network, has the advantages of sensitive response, controllable triggering conditions, and high insulation reliability at room temperature. It has little impact on the normal charging and discharging process of the battery cell 100, and can stably maintain a conductive state with a medium resistance value after triggering, further improving the pressure relief reliability under thermal runaway.

[0046] Regarding the specific form in which multiple conductive particles 312 are disposed on the insulating body 311, in some embodiments, the insulating body 311 has a bearing surface with multiple positioning grooves distributed on the bearing surface, and a connecting groove is provided between two adjacent positioning grooves. Multiple conductive particles 312 are disposed in multiple positioning grooves, thereby maintaining an independent state. When the electrode assembly 12 thermally runs away and the temperature of the battery cell 100 reaches the melting point of the conductive particles 312, the conductive particles 312 can melt and flow into the connecting groove, thereby enabling adjacent conductive particles 312 to conduct to each other.

[0047] Please continue reading. Figure 6 In other embodiments, a microporous structure 3111 is formed inside the insulating body 311, and multiple conductive particles 312 are embedded in the microporous structure 3111 of the insulating body 311.

[0048] "The interior of the insulating body 311 has a microporous structure 3111" means that the interior of the insulating body 311 has a large number of small pore structures that are independent of each other or only partially connected. Multiple conductive particles 312 can be embedded in different pores one by one. At room temperature, each conductive particle 312 is separated by the insulating body 311 around the pores, maintaining an independent state and not spontaneously forming a connected conductive path. When the temperature rises to the melting point of the conductive particles 312, the particles melt into a liquid state, expand in volume, and wet the inner walls of the pores, thus forming a connected liquid conductive path between adjacent pores. Ultimately, this forms a current-limiting conductive path with a medium resistance value. This structure fully utilizes the internal space of the insulating body 311, allowing for the placement of as many conductive particles 312 as possible. This ensures that after thermal runaway of the electrode assembly 12, the thermally triggered insulation component can reduce its resistance value from high to medium. Simultaneously, the microporous structure 3111 provides more stable fixation for the conductive particles 312, preventing displacement of the conductive particles 312 during long-term cycling of the battery cell 100 and improving insulation reliability during room temperature operation. Furthermore, the microporous structure 3111 also restricts the flow freedom of the liquid conductive particles 312, reducing the probability of forming a large-area continuous conductive film and ensuring that the thermally triggered conductive component 31 achieves a medium-resistance connection rather than a short-circuit connection.

[0049] Please continue reading. Figure 6 In some embodiments, the thermally triggered conductive element 31 further includes an adhesive that bonds between the insulating body 311 and the conductive particles 312.

[0050] There are various material options for the "binder," such as inorganic materials like aluminum phosphate, silicates, and silica sol. These materials typically have high-temperature resistance properties and can maintain structural stability at temperatures up to 800°C.

[0051] In the above technical solution, the adhesive is bonded and fixed between the insulating body 311 and the conductive particles 312. On the one hand, it can improve the positional stability of the conductive particles 312 in the microporous structure 3111, and prevent the conductive particles 312 from shifting or misaligning due to vibration, charging and discharging expansion and contraction during normal use of the battery cell 100, thus preventing the premature formation of abnormal conductive paths at room temperature. On the other hand, the adhesive can usually maintain structural stability at high temperatures, ensuring that the thermally triggered conductive component 31 can maintain structural stability throughout the entire process of thermal runaway.

[0052] In other embodiments, the insulating body 311 is made of at least one of ceramic fibers and ceramic particles.

[0053] The material of "ceramic fiber and ceramic particles" can be any one of alumina, zirconium oxide, or silicon oxide, or a composite felt or composite sintered body made of the above materials.

[0054] In the above technical solution, the ceramic material has the characteristics of good insulation at room temperature and excellent high temperature resistance. Even in the high temperature environment of 100°C thermal runaway of a single battery cell, it is difficult to decompose and fail. It can stably maintain the overall structural shape of the thermally triggered conductive component 31 and ensure that the current limiting conductive path can function normally.

[0055] It should be noted that the two parallel technical features mentioned above, "the thermally triggered conductive element 31 also includes an adhesive, which is bonded between the insulating body 311 and the conductive particles 312" and "the material of the insulating body 311 includes at least one of ceramic fiber and ceramic particles", can be selected or provided simultaneously. When provided simultaneously, the adhesive can also bond the ceramic fiber and ceramic particles to form the insulating body 311, and at the same time solidify the insulating body 311 and the conductive particles 312 into coatings, sheets, blocks and other characteristic forms to adapt to the shape or internal structure of the battery cell 100.

[0056] In some embodiments, the melting point of the conductive particles 312 is between 250°C and 300°C; and / or, In the above technical solution, the melting point of the conductive particles 312 is set between 250°C and 300°C. This temperature range corresponds to the typical temperature range of the battery thermal runaway entering the high-temperature exothermic stage. It will not cause the battery cell 100 to be falsely triggered when it is working at normal high temperature due to the trigger temperature being too low, nor will it miss the best opportunity to release the residual high voltage in the early stage of thermal runaway due to the trigger temperature being too high.

[0057] In other embodiments, the conductive particles 312 are made of bismuth-based alloys or tin-based alloys.

[0058] In the above technical solution, the conductive particles 312 are made of bismuth-based alloys or tin-based alloys. These low-melting-point alloys have stable performance, good solid-state stability at room temperature, and can quickly melt to form a conductive phase after reaching the melting point. They are also low in cost and suitable for large-scale industrial production applications.

[0059] It should be noted that the two parallel technical features mentioned above, "the melting point of the conductive particles 312 is between 250°C and 300°C" and "the material of the conductive particles 312 includes bismuth-based alloys or tin-based alloys", can be set either one or both.

[0060] Please see Figure 2 In some embodiments, the thermally triggered conductive element 31 is connected to two electrode terminals 21.

[0061] "The thermally triggered conductive element 31 is connected to the two electrode terminals 21" means that the two ends of the thermally triggered conductive element 31 are directly connected to the two electrode terminals 21, and it can provide a complete current-limiting conductive path. In an embodiment where there are two end caps 2, and the two end caps 2 are respectively located at both ends of the main housing 1, the thermally triggered conductive element 31 can be located in the receiving cavity 11 of the main housing 1, bypassing the electrode assembly 12 in the main housing 1, and simultaneously connected to the electrode terminals 21 on the two end caps 2.

[0062] In the above technical solution, the thermally triggered conductive element 31 is directly connected to the two electrode terminals 21. The discharge current can flow directly from the positive terminal to the negative terminal through the thermally triggered conductive element 31. The current-limiting conductive path is more direct, and the resistance value of the current-limiting conductive path is highly controllable. It can accurately control the discharge current within the design range, improving the situation where excessive current causes short circuits or insufficient current fails to effectively discharge residual high voltage.

[0063] The end cap 2 of the battery cell 100 typically has a metal body 22, an inner insulating member 24, and an outer insulating member 25. The inner insulating member 24 is disposed on the side of the metal body 22 facing the electrode assembly 12, and the outer insulating member 25 is disposed on the side of the metal body 22 away from the electrode assembly 12. The electrode terminal 21 typically has a terminal post 211, an inner connector 212, and an outer connector 213. The terminal post 211 typically penetrates the metal body 22, the inner insulating member 24, and the outer insulating member 25. The inner connector 212 is disposed at the inner end of the terminal post 211 near the electrode assembly 12. The outer connector 213 is disposed at the outer end of the terminal post 211 away from the electrode assembly 12 and abuts against the outer insulating member 24. The outer connector 213 is used to connect the current collector. A sealing ring 23 is usually provided between the terminal post 211 and the mounting hole 221 of the metal body 22. Under normal circumstances, the sealing ring 23 not only has a sealing function, but also needs to play an insulating function between the terminal post 211 and the metal body 22 when the battery cell 100 is in normal condition.

[0064] Please continue reading. Figure 2 In some embodiments, an end cap 2 is provided, the end cap 2 has a metal body 22, and a thermally triggered conductive element 31 covers the side of the metal body 22 facing the electrode assembly 12 and isolates the metal body 22 from the electrode assembly 12; wherein, two electrode terminals 21 are respectively passed through and connected to the thermally triggered conductive element 31.

[0065] Based on the principle that "the thermally triggered conductive element 31 covers the side of the metal body 22 facing the electrode assembly 12 and isolates the metal body 22 from the electrode assembly 12", the thermally triggered conductive element 31 in this embodiment has a high resistance value at room temperature and is in an insulating state, thus effectively performing the function of the inner insulating element 24. Therefore, the thermally triggered conductive element 31 can be consistent with the inner insulating element 24 in terms of structural shape, with improvements only made in internal structure and material.

[0066] In the above technical solution, the use of thermally triggered conductive element 31 to replace the traditional internal insulation element 24 not only achieves insulation isolation between electrode assembly 12 and metal body 22, but also reduces the space occupied by thermally triggered conductive element 31 in the internal space of main housing 1, which can free up space to accommodate more electrode active materials and effectively improve the overall energy density of battery cell 100. Furthermore, the thermally triggered conductive element 31 contacts the metal body 22 on one hand and connects to two electrode terminals 21 on the other, thus forming two current-limiting conductive paths: "electrode terminal 21, thermally triggered conductive element 31, electrode terminal 21" and "electrode terminal 21, thermally triggered conductive element 31, metal body 22, thermally triggered conductive element 31, electrode terminal 21", which increases the redundancy of the discharge path.

[0067] Specifically, the electrode terminal 21 includes a pole post 211 and an inner connector 212; the pole post 211 passes through the thermally triggered conductive element 31; the inner connector 212 is disposed at the inner end of the pole post 211, the inner connector 212 is connected to the tab of the electrode assembly 12, and abuts against the thermally triggered conductive element 31.

[0068] Regarding "internal connector 212 connected to the tab of electrode assembly 12", the tab of electrode assembly 12 includes positive tab 121 and negative tab 122. The internal connector 212 of the positive terminal is connected to the positive tab 121, and the internal connector 212 of the negative terminal is connected to the negative tab 122.

[0069] In the above technical solution, the contacting action of the inner connector 212 can keep the thermally triggered conductive element 31 in close contact with the inner surface of the metal body 22 at all times, reducing the probability that the thermally triggered conductive element 31 may shift and loosen due to the expansion and contraction of the electrode assembly 12 during the long-term cycle charging and discharging process of the battery cell 100, and further improving the insulation reliability of the thermally triggered conductive element 31 at room temperature.

[0070] Please see Figure 3 or Figure 4 In some embodiments, the end cap 2 has a metal body 22; an electrical connector 3 is provided between the two electrode terminals 21 and the corresponding metal body 22, and at least one of the electrical connectors 3 is configured as a thermally triggered conductive element 31.

[0071] In the above technical solution, an electrical connector 3 is provided between the electrode terminal 21 and the metal body 22, and one of the electrical connectors 3 is set as a thermally triggered conductive element 31. At room temperature, the thermally triggered conductive element 31 maintains a high resistance value insulation state, and the electrode terminal 21 and the metal body 22 maintain a reliable insulation separation, which will not interfere with the normal charging and discharging process of the battery cell 100. When the electrode assembly 12 experiences thermal runaway, after the temperature of the battery cell 100 rises to the trigger threshold, the thermally triggered conductive element 31 changes to a medium resistance value current-limiting conductive state, connecting the corresponding electrode terminal 21 to the metal body 22. The other electrode terminal 21 also forms a path with the metal body 22 through the electrical connector 3, ultimately forming a complete current-limiting conductive path connecting the two electrode terminals 21 through the metal body 22, so that the residual high voltage inside the electrode assembly 12 is slowly discharged with controlled current.

[0072] Please continue reading. Figure 3 or Figure 4 In some embodiments, one of the electrical connectors 3 is configured as a thermally triggered conductive element 31, and the other electrical connector 3 is configured as an equipotential connector 32; the equipotential connector 32 is disposed between the electrode terminal 21 corresponding to the positive electrode tab 121 and the metal body 22; the thermally triggered conductive element 31 is disposed between the electrode terminal 21 corresponding to the negative electrode tab 122 and the metal body 22.

[0073] "Equipotential bonding element 32" refers to the element that enables the positive electrode tab 121 to maintain low resistance conduction with the metal body 22. Regardless of whether it is at room temperature or in a thermal runaway high temperature state, it can maintain a low resistance value so that the positive electrode tab 121 and the metal body 22 are always at the same potential.

[0074] In the above technical solution, the positive electrode and the metal body 22 are connected in a long-term stable manner through the equipotential connector 32, maintaining the equipotential state between the positive electrode and the metal body 22. This can reduce the potential difference between the positive electrode and the metal body 22 during normal charging and discharging, effectively alleviate the electrochemical corrosion problem caused by the potential difference, improve the long-term corrosion resistance of the metal body 22 of the main shell 1 and the end cover 2, and extend the overall service life of the battery cell 100.

[0075] Please see Figure 3 In some embodiments, the thermally triggered conductive element 31 is disposed at one end of the end cap 2 away from the electrode assembly 12; the electrode terminal 21 includes a pole post 211 and an external connector 213; the pole post 211 passes through the thermally triggered conductive element 31; the external connector 213 is disposed at the outer end of the pole post 211 and abuts against the thermally triggered conductive element 31.

[0076] Based on the fact that "the thermal trigger conductive element 31 is disposed at one end of the end cap 2 away from the electrode assembly 12", "the pole post 211 passes through the thermal trigger conductive element 31", and "the external connector 213 abuts against the thermal trigger conductive element 31", the thermal trigger conductive element 31 in this embodiment has a high resistance value at room temperature and is in an insulating state, thus actually performing the function of the external insulating element 25. Therefore, the thermal trigger conductive element 31 can be consistent with the external insulating element 25 in terms of structural shape, with improvements only made in internal structure and material.

[0077] In the above technical solution, the use of thermally triggered conductive element 31 to replace the traditional external insulation element 25 not only achieves insulation isolation between the external connector 213 and the metal body 22, but also reduces the space occupied by the thermally triggered conductive element 31 on the external space of the battery cell 100, effectively improving the overall energy density of the battery cell 100.

[0078] Please see Figure 4 In some embodiments, the electrode terminal 21 includes a post 211 and a sealing ring 23; the post 211 passes through a mounting hole 221 in the metal body 22; the sealing ring 23 is sleeved on the post 211 and abuts against the metal body 22, and at least a portion of the sealing ring 23 is located between the inner wall of the mounting hole 221 and the post 211; wherein, the sealing ring 23 includes a thermally triggered conductive element 31.

[0079] Since the sealing ring 23 is located between the pole post 211 and the metal body 22, the sealing ring 23 can also contribute to the current-limiting conductive path. Based on this, "the sealing ring 23 includes the thermally triggered conductive element 31" means that the sealing ring 23 can be entirely set as the thermally triggered conductive element 31, or it can be partially set as the thermally triggered conductive element 31. In this embodiment, the thermally triggered conductive element 31 has a high resistance value at room temperature and is in an insulating state, which can play the insulating function of the sealing ring 23. Therefore, the thermally triggered conductive element 31 can be consistent with the outer insulating element 25 in terms of structural shape, and only the internal structure and material can be improved.

[0080] In the above technical solution, the thermal trigger conductive element 31 is set on the sealing ring 23, which not only realizes the insulation isolation between the pole post 211 and the metal body 22, but also reduces the space occupied by the thermal trigger conductive element 31 on the end cover 2, effectively improving the overall energy density of the battery cell 100.

[0081] Please see Figure 5 In some embodiments, the sealing ring 23 includes a sealing body 231 and a limiting protrusion 232; the sealing body 231 is elastically disposed between the inner wall of the mounting hole 221 and the electrode post 211; the limiting protrusion 232 is connected to one end of the sealing body 231 facing the electrode assembly 12 and abuts against the metal body 22; wherein, the limiting protrusion 232 includes a thermally triggered conductive element 31.

[0082] "The sealing body 231 is elastically set" means that the sealing body 231 is usually made of elastic rubber or elastic polymer material; "The limiting protrusion 232 is connected to the end of the sealing body 231 facing the electrode assembly 12" means that the limiting protrusion 232, like the sealing body 231, is also sleeved around the pole post 211, but it is located at the inner end of the sealing body 231.

[0083] In the above technical solution, the sealing body 231 is made of elastic material and is set between the inner wall of the mounting hole 221 and the pole post 211. It can fill the gap between the inner wall of the mounting hole 221 and the pole post 211 by its own elastic deformation, thereby improving the sealing effect. On this basis, a limiting protrusion 232 is provided at one end of the sealing body 231 facing the electrode assembly 12. The limiting protrusion 232 can abut against the metal body 22 outward, thereby providing a limit for the sealing ring 23 during the assembly of the end cap 2. Moreover, since the limiting protrusion 232 includes a thermally triggered conductive element 31, the thermally triggered conductive element 31 can simultaneously contact the pole post 211 and the metal body 22, thereby forming a complete current-limiting conductive path and realizing the slow release of residual high voltage inside the electrode assembly 12.

[0084] In some embodiments, the thermally triggered conductive element 31 is configured as a negative temperature coefficient thermistor.

[0085] A "negative temperature coefficient thermistor" refers to a thermistor whose resistance gradually decreases as temperature increases. Its resistance-temperature characteristic aligns with the functional requirements of the thermally triggered conductive element 31 in this application. At room temperature, the negative temperature coefficient thermistor itself possesses a high resistance value, reliably maintaining the insulation between the two electrode terminals 21 without interfering with the normal charging and discharging process of the battery cell 100. When thermal runaway occurs in the electrode assembly 12 and the temperature of the battery cell 100 continues to rise to the trigger temperature threshold, the resistance value of the negative temperature coefficient thermistor will continuously decrease with increasing temperature, eventually stabilizing in a medium resistance range of 50Ω to 5000Ω, providing a current-limiting conductive path for the two electrode terminals 21 that meets design requirements. Using a mature negative temperature coefficient thermistor as the thermally triggered conductive element 31 results in a high degree of device standardization, allowing direct selection and adaptation for battery cells 100 with different capacities and residual voltage levels. This effectively simplifies the structural design and processing assembly of the battery cell 100, making it suitable for large-scale industrial production.

[0086] In other embodiments, the thermally triggered conductive element 31 is provided with a phase change heat absorption structure.

[0087] "Phase change heat absorption structure" refers to a structure that can absorb heat through its own phase change. It is usually made of phase change material, which has a preset phase change temperature. The phase change temperature is usually set to be higher than the trigger temperature threshold of the thermal trigger conductive element 31. Common phase change heat absorption structures can be made of organic or inorganic phase change materials. Organic phase change materials can be any one of paraffin, fatty acids, or polyethylene glycol, while inorganic phase change materials can be hydrated salt phase change materials.

[0088] In the above technical solution, when the temperature of thermal runaway of the battery cell 100 exceeds the trigger temperature threshold of the thermal triggering conductive element 31 and rises to the phase change temperature of the phase change heat absorption structure, the phase change heat absorption structure can undergo a phase change in response to the Joule heat generated during the discharge process of the thermal triggering conductive element 31, and absorb a large amount of heat from the thermal triggering conductive element 31, thereby improving the situation where the thermal triggering conductive element 31 is prone to becoming a local high temperature hot spot, and thus maintaining the thermal stability during controlled discharge.

[0089] It should be noted that the two parallel technical features mentioned above, "the thermally triggered conductive element 31 is set as a negative temperature coefficient thermistor" and "the thermally triggered conductive element 31 is provided with a phase change heat absorption structure", can be set either one or both.

[0090] Secondly, the battery device proposed in this application includes the battery cell 100 described above. The specific structure of the battery cell 100 is as described in the above embodiments. Since this battery device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0091] To further understand the battery device provided in this application, please refer to [link / reference]. Figure 7 , Figure 7 This is an exploded structural diagram of an embodiment of the battery device provided in this application. The battery device 1000 typically includes a housing 200 and battery cells 100. The housing 200 typically has a mounting cavity through which the battery cells 100 are loaded. The basic structure of the housing 200 generally includes a housing body 210 and a housing cover 220. The housing cover 220 is disposed on the housing body 210 and, together with the housing body 210, defines the aforementioned mounting cavity. The mounting cavity may be primarily formed in the housing body 210, in which case the housing body 210 can be understood as an upward-opening basin-shaped structure, and the housing cover 220 covers the housing body 210 to cover the aforementioned mounting cavity. Alternatively, the mounting cavity may be primarily formed in the housing cover 220, in which case the housing cover 220 can be understood as a downward-opening cover-shaped structure, and the housing cover 220 covers the housing body 210 to enclose the battery cells 100 mounted on the housing body 210. Of course, the structure of the housing 200 is not limited to these.

[0092] The number of battery cells 100 in the housing 200 can be one or more. When multiple battery cells 100 are provided, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 100 are connected in both series and parallel configurations. These multiple battery cells 100 can be directly connected in series, parallel, or in a mixed manner to form a battery assembly. Alternatively, the multiple battery cells 100 can first be connected in series, parallel, or in a mixed manner to form a battery module, and then the multiple battery modules can be connected in series, parallel, or in a mixed manner to form a battery assembly. The battery device 1000 may also include other structures, such as a busbar, for realizing the electrical connection between multiple battery cells 100 or multiple battery modules. The battery cell 100 may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc., and this application embodiment is not limited to these. The battery cell 100 can be cylindrical, flat, cuboid or other shapes. Generally, the battery cell 100 is divided into three types according to the packaging method: cylindrical battery cell 100, square battery cell 100 and pouch battery cell 100. The embodiments of this application are not limited to this.

[0093] Thirdly, the energy storage device 10000 proposed in this application includes the aforementioned battery device 1000. The specific structure of the battery device 1000 is as described in the above embodiments. Since this energy storage device 10000 adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here. Figure 8 The energy storage device 10000 includes an energy storage cabinet 2000, which contains multiple energy storage compartments, each of which contains the aforementioned battery device 1000.

[0094] In one application scenario, the energy storage device 10000 can be connected to the power supply network, storing electrical energy in the internal battery device 1000 during off-peak hours and transmitting electrical energy to the outside during peak hours, thus playing a role in peak shaving and valley filling and reducing the pressure on the power supply network.

[0095] The above descriptions provided in this application are merely exemplary embodiments of this application and do not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A battery cell, characterized in that, include: The main housing has a receiving cavity, in which an electrode assembly is disposed, and the receiving cavity has an opening; as well as, At least one end cap is provided on the opening of the receiving cavity, and the at least one end cap is provided with two electrode terminals, which are respectively electrically connected to the positive electrode and the negative electrode of the electrode assembly; A thermally triggered conductive element is provided between the two electrode terminals, and the thermally triggered conductive element is configured to have different resistance values ​​in at least two temperature ranges.

2. The battery cell as described in claim 1, characterized in that, The thermally triggered conductive element is configured such that its resistance in the first temperature range is greater than its resistance in the second temperature range. The first temperature range is lower than the second temperature range.

3. The battery cell as described in claim 1, characterized in that, The thermally triggered conductive element includes: An insulating body is disposed on the end cap; and, Multiple conductive particles are disposed on the insulating body, with adjacent conductive particles being independently disposed, and the multiple conductive particles are configured to be able to melt upon heating and form a conductive phase.

4. The battery cell as described in claim 3, characterized in that, The insulating body has a microporous structure inside, and the plurality of conductive particles are embedded in the microporous structure of the insulating body.

5. The battery cell as described in claim 4, characterized in that, The thermally triggered conductive element further includes an adhesive, which is bonded between the insulating body and the conductive particles; and / or The insulating body is made of at least one of ceramic fibers and ceramic particles.

6. The battery cell as described in claim 3, characterized in that, The conductive particles have a melting point between 250°C and 300°C; and / or, The conductive particles are made of bismuth-based alloys or tin-based alloys.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The thermally triggered conductive element is connected to the two electrode terminals.

8. The battery cell as described in claim 7, characterized in that, One end cap is provided, the end cap has a metal body, the thermally triggered conductive element covers the side of the metal body facing the electrode assembly, and isolates the metal body from the electrode assembly; The two electrode terminals are respectively inserted into and connected to the thermally triggered conductive element.

9. The battery cell as described in claim 7, characterized in that, The electrode terminals include: The electrode post is inserted through the thermally triggered conductive element; and, An inner connector is disposed at the inner end of the electrode post, the inner connector is connected to the tab of the electrode assembly, and abuts against the thermally triggered conductive element.

10. The battery cell according to any one of claims 1 to 6, characterized in that, The end cap has a metal body; An electrical connector is provided between the two electrode terminals and the corresponding metal body, and at least one of the electrical connectors is configured as the thermally triggered conductive element.

11. The battery cell as described in claim 10, characterized in that, One of the electrical connectors is configured as the thermally triggered conductive element, and the other electrical connector is configured as an equipotential connector; The equipotential bonding member is disposed between the electrode terminal corresponding to the positive electrode tab and the metal body; The thermally triggered conductive element is disposed between the electrode terminal corresponding to the negative electrode tab and the metal body.

12. The battery cell as described in claim 10, characterized in that, The thermally triggered conductive element is disposed at the end of the end cap opposite to the electrode assembly; The electrode terminals include: The electrode post is inserted through the thermally triggered conductive element; and, An external connector is disposed at the outer end of the pole post, and the external connector abuts against the thermally triggered conductive element.

13. The battery cell as described in claim 10, characterized in that, The electrode terminals include: The pole post passes through the mounting hole in the metal body; and, A sealing ring is fitted onto the pole post and abuts against the metal body, with at least a portion of the sealing ring located between the inner wall of the mounting hole and the pole post; The sealing ring includes the thermally triggered conductive element.

14. The battery cell as described in claim 13, characterized in that, The sealing ring includes: A sealing body, elastically configured, is disposed between the inner wall of the mounting hole and the pole post; and, A limiting protrusion is connected to one end of the sealing body facing the electrode assembly, and the limiting protrusion abuts against the metal body; The limiting protrusion includes the thermally triggered conductive element.

15. The battery cell as described in claim 1, characterized in that, The thermally triggered conductive element is configured as a negative temperature coefficient thermistor; and / or, The thermally triggered conductive component is provided with a phase change heat absorption structure.

16. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 15.

17. An energy storage device, characterized in that, Includes the battery device as described in claim 16.

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