Battery cell and thermal runaway test system

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell and a thermal runaway test system. The battery cell comprises a shell; a pole core; the first pole column is connected with the first pole piece; the second pole column is connected with the second pole piece; a third pole; the contact piece is in insulated contact with the first pole piece or the second pole piece; and one end of the leading-out piece is connected with the contact piece, and the other end of the leading-out piece is connected with the third pole. According to different research contents, the contact piece can be in insulation contact with one pole piece in the pole core, the third pole column and the pole column correspondingly connected with the pole piece not in contact with the contact piece are connected to the two ends of a high-voltage power source respectively, power source parameters of the high-voltage power source are set according to the research contents, and thermal runaway triggering is carried out. Therefore, high-voltage arc discharge is generated on the pole piece in contact with the contact piece, and thermal runaway is induced. The mechanism and the phenomenon of battery cell triggering thermal runaway are very close to those of real internal short thermal runaway, and the battery cell can be widely applied to thermal runaway, thermal diffusion mechanism research, protection material type selection, safety evaluation and the like.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell and thermal runaway testing system. Background Art

[0002] During the use of batteries, thermal runaway and heat diffusion may occur due to various reasons. In order to suppress the occurrence of thermal runaway, it is necessary to have an in-depth understanding of the mechanism and protection plan of thermal runaway. This requires the creation of a triggering method that is close to real thermal runaway.

[0003] Currently, the main methods for triggering thermal runaway include heating and acupuncture. These methods have the following problems: excessive input energy, excessive heat generation, poor consistency, or affecting battery cell assembly. Therefore, the use of these thermal runaway triggering methods deviates greatly from the actual internal short circuit phenomenon, making it impossible to conduct in-depth mechanism research and expand applications. Summary of the Invention

[0004] Based on this, the present application provides a battery cell and thermal runaway test system to conduct thermal runaway triggering experiments, so that the simulation results are close to the actual internal short thermal runaway situation, thereby providing support for in-depth research on the thermal runaway mechanism.

[0005] In one aspect, the present application provides a battery cell, comprising:

[0006] shell;

[0007] The pole core is arranged in the shell, and the pole core includes a first pole piece and a second pole piece;

[0008] A first pole, the first pole is provided on the housing and connected to the first pole piece;

[0009] A second pole, the second pole is provided on the housing and connected to the second pole piece;

[0010] A third pole, the third pole is provided on the housing;

[0011] a contact member, the contact member being disposed between the first pole piece and the second pole piece and being insulated from and in contact with one of the first pole piece and the second pole piece;

[0012] The lead-out piece is arranged in the shell, and one end of the lead-out piece is connected to the contact piece, and the other end is connected to the third pole.

[0013] In a possible implementation, the contact member is a metal member, and the melting point of the contact member is higher than 400°C.

[0014] In a possible implementation, the contact member includes an electrode portion and a lead portion, the electrode portion is located on a side of the contact member away from the lead portion, and the lead portion is located on a side of the contact member close to the lead portion.

[0015] In a possible implementation, the electrode portion is a metal sheet or a metal coil.

[0016] In a possible implementation, the lead-out portion is a metal wire.

[0017] In a possible implementation, an insulating layer is provided on the surface of the electrode portion.

[0018] In a possible implementation, the contact element is one of a metal wire, a metal coil, a metal sheet, a combination of a metal wire and a metal coil, and a combination of a metal wire and a metal sheet.

[0019] In a possible implementation, the thickness of the contact element is less than 150 μm.

[0020] In a possible implementation, the first electrode is a positive electrode, the second electrode is a negative electrode, and the contact element is insulated contact with the second electrode.

[0021] In one possible implementation, the housing includes a shell and a cover plate, the cover plate is arranged on the shell, the pole core is arranged in the shell, the third pole is arranged on the cover plate, the contact piece is arranged in the pole core, and the extension direction is parallel to the plane where the cover plate is located, the lead-out piece is arranged on the shell, and one side is connected to the contact piece, and the other side extends toward the cover plate to be connected to the third pole.

[0022] In a possible implementation, the shell includes a side plate, and the lead-out member is provided on the side plate.

[0023] In a possible implementation, the side plate is provided with an avoidance cavity, the avoidance cavity extends toward the cover plate, and the lead-out piece is provided in the avoidance cavity.

[0024] In a possible implementation, the side plate is an insulating member.

[0025] In a possible implementation, the first pole or the second pole is provided on the cover plate, and a gap exists between the third pole and the first pole or the second pole.

[0026] In a possible implementation, the lead-out member is a metal wire or a metal sheet.

[0027] In a possible implementation, the third pole includes an insulating ring and a conductive pole, the conductive pole is passed through the housing, the insulating ring connects the conductive pole and the housing, and the lead-out piece is connected to the conductive pole.

[0028] In a possible implementation, the third pole further includes a sealing ring, which is used to seal the gap between the insulating ring and the housing.

[0029] On the other hand, the present application provides a thermal runaway testing system, including a high-voltage power supply and the above-mentioned battery cell, one end of the high-voltage power supply is connected to the third pole, and the other end is connected to the second pole or the first pole.

[0030] In one possible implementation, the contact member is a metal wire, the contact area between the contact member and the first electrode or the second electrode is S1, the voltage applied by the high-voltage power supply is V1, S1 and V1 satisfy: 300*S1≤V1≤5000*S1, where V1 is in V and S1 is in mm. 2 .

[0031] In one possible implementation, the contact member is a metal sheet, the contact area between the contact member and the first electrode piece or the second electrode piece is S2, the voltage applied by the high-voltage power supply is V2, S2 and V2 satisfy: 0.7*S2≤V2≤2*S2, where the unit of V2 is V and the unit of S2 is mm 2 .

[0032] In one possible implementation, the contact member is a combination of a metal wire and a metal coil, and the contact member is insulated from the first pole piece or the second pole piece through the metal coil. The contact area is S3, and the voltage applied by the high-voltage power supply is V3. S3 and V3 satisfy: 0.3*S3≤V3≤8*S3, where the unit of V3 is V and the unit of S3 is mm. 2 .

[0033] In one possible implementation, the contact member is a combination of a metal wire and a metal sheet, the contact member is insulated from the first electrode or the second electrode through the metal sheet, the contact area is S4, the voltage applied by the high-voltage power supply is V4, S4 and V4 satisfy: 0.7*S4≤V4≤2*S4, where the unit of V4 is V and the unit of S4 is mm 2 .

[0034] In one possible implementation, the first electrode is a positive electrode, the second electrode is a negative electrode, and the voltage applied by the high-voltage power supply when the contact piece is insulated contact with the second electrode is lower than the voltage applied by the high-voltage power supply when the contact piece is insulated contact with the first electrode.

[0035] In one possible implementation, the first pole or the second pole and the third pole are arranged on the same cover plate, and on the side of the cover plate close to the shell, there is a gap L between the connection position of the third pole and the first pole and the first pole piece, or there is a gap L between the connection position of the third pole and the second pole and the second pole piece. The voltage applied by the high-voltage power supply is V5, and L satisfies: L>0.1V5, where the unit of V5 is V and the unit of L is mm.

[0036] The battery cell and thermal runaway test system provided by the present application is configured by providing a third pole on the outer shell, providing a contact on one of the pole pieces in the pole core, and connecting the contact to the third pole via a lead-out piece. Depending on the research content, the contact can be insulated from one of the pole pieces in the pole core. The third pole and the pole connected to the pole piece that is not in contact with the contact are respectively connected to the two ends of a high-voltage power supply. The power supply parameters of the high-voltage power supply are set according to the research content to trigger thermal runaway, thereby generating a high-voltage arc on the pole piece in contact with the contact piece, inducing thermal runaway. The mechanism and phenomenon of thermal runaway triggered by the battery cell are very close to those of real internal short-circuit thermal runaway. By adjusting the power supply parameters of the high-voltage power supply and selecting the contact position of the contact piece, thermal runaway experiments can be performed at different positions in the battery cell. The battery cell can be widely used in thermal runaway, heat diffusion mechanism research, protective material selection, safety evaluation and other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0039] Figure 2 for Figure 1 A schematic diagram of a partially exploded structure of the battery cell shown;

[0040] Figure 3 for Figure 1 One of the structural diagrams of the connection between the contact piece and the lead-out piece in the battery cell shown;

[0041] Figure 4 for Figure 1 The second structural diagram of the connection between the contact piece and the lead-out piece in the battery cell shown;

[0042] Figure 5 for Figure 1 A schematic diagram of the partially exploded structure of the battery cell from another angle.

[0043] Description of reference numerals:

[0044] 100-battery cell; 10-shell; 11-shell; 111-side plate; 12-cover; 121-first cover; 122-second cover; 20-pole core; 30-first pole; 40-second pole; 50-third pole; 51-conductive pole; 52-insulating ring; 53-sealing ring; 60-contact piece; 61-electrode part; 62-lead-out part; 70-lead-out piece. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to a fixed connection, an indirect connection via an intermediate medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0047] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0048] The terms "first", "second" and "third" (if any) in the description and claims of this application and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0049] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or display that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product or display.

[0050] During the use of batteries, thermal runaway and heat diffusion may occur due to various reasons. In order to suppress the occurrence of thermal runaway, it is necessary to have an in-depth understanding of the mechanism and protection plan of thermal runaway. This requires the creation of a triggering method that is close to real thermal runaway.

[0051] Currently, the main methods for triggering thermal runaway include heating and acupuncture. These methods have the following problems: excessive input energy, excessive heat generation, poor consistency, or problems that affect battery cell assembly. Therefore, the use of these thermal runaway triggering methods deviates greatly from the actual internal short circuit phenomenon, making it impossible to conduct in-depth mechanism research and expand applications. As a result, the safety evaluation derived from these methods cannot represent the actual safety capabilities, or the safety protection measures are insufficient or redundant.

[0052] After repeated thinking and verification, the inventor found that if an additional pole is set in the battery cell and a metal part that induces thermal runaway is set on the pole piece, the pole is connected to the metal part, and then an external high-voltage power supply is used. The high voltage electricity applied to the metal part will generate a high-voltage arc inside the pole piece, thereby inducing thermal runaway. The experimental results are closer to the situation when thermal runaway occurs due to a real internal short circuit. In addition, different experiments can be carried out by adjusting the setting position of the metal part, the voltage, current, and action time of the high-voltage power supply, which is convenient for in-depth study of the mechanism of thermal runaway.

[0053] In view of this, the present application provides a battery cell, comprising:

[0054] shell;

[0055] The pole core is arranged in the shell, and the pole core includes a first pole piece and a second pole piece;

[0056] A first pole, the first pole is provided on the housing and connected to the first pole piece;

[0057] A second pole, the second pole is provided on the housing and connected to the second pole piece;

[0058] A third pole, the third pole is provided on the housing;

[0059] a contact member, the contact member being disposed between the first pole piece and the second pole piece and being insulated from and in contact with one of the first pole piece and the second pole piece;

[0060] The lead-out piece is arranged in the shell, and one end of the lead-out piece is connected to the contact piece, and the other end is connected to the third pole.

[0061] By providing a third pole on the outer shell, providing a contact on one of the pole pieces in the pole core, and connecting the contact to the third pole via a lead-out piece, the contact can be made to insulate contact with one of the pole pieces in the pole core, depending on the research content. By applying an external high-voltage power supply, the third pole and the pole corresponding to the pole piece that is not insulated from the contact piece are connected to the two ends of the high-voltage power supply. The power supply parameters of the high-voltage power supply are set according to the research content to trigger thermal runaway, thereby generating a high-voltage arc on the pole piece insulated from the contact piece, inducing thermal runaway. The mechanism and phenomenon of thermal runaway triggered by this battery cell are very close to those of real internal short thermal runaway. By adjusting the power supply parameters of the high-voltage power supply and selecting the contact position of the contact piece, thermal runaway experiments can be performed at different positions in the battery cell. This battery cell can be widely used in thermal runaway, heat diffusion mechanism research, protective material selection, safety evaluation and other aspects.

[0062] The contents of this application will be described in detail below with reference to the accompanying drawings so that those skilled in the art can understand the contents of this application more clearly and in detail.

[0063] Figure 1 A schematic diagram of the structure of the battery cell provided in an embodiment of the present application. Figure 2 for Figure 1 Schematic diagram of the partial exploded structure of the battery cell shown. Figure 3 for Figure 1 One of the structural schematic diagrams of the connection between the contact piece and the lead-out piece in the battery cell shown. Figure 4 for Figure 1 The second structural diagram of the connection between the contact piece and the lead-out piece in the battery cell is shown. Figure 5 for Figure 1 A schematic diagram of the partially exploded structure of the battery cell from another angle.

[0064] like Figure 1 and Figure 2 As shown, an embodiment of the present application provides a battery cell 100 for use in a thermal runaway test system to conduct a thermal runaway triggering experiment. The battery cell 100 includes a housing 10, a core 20, a first pole 30, a second pole 40, a third pole 50, a contact 60, and a lead 70. The housing 10 is used to protect the components in the battery cell 100. The first pole 30, the second pole 40, and the third pole 50 are respectively disposed on the housing 10. The core 20, the contact 60, and the lead 70 are respectively disposed in the housing 10.

[0065] The pole core 20 includes a first pole piece and a second pole piece.

[0066] In a possible implementation, a plurality of first pole pieces and second pole pieces are stacked on each other to form a stacked core, and a diaphragm may be provided between the first pole piece and the second pole piece.

[0067] In another possible implementation, the first pole piece and the second pole piece are stacked and wound to form a winding core, and a diaphragm may be provided between the first pole piece and the second pole piece.

[0068] The first pole 30 is connected to the first pole piece, and the second pole 40 is connected to the second pole piece.

[0069] In a possible implementation, the first electrode is a positive electrode, the second electrode is a negative electrode, the first electrode 30 is a positive electrode, and the second electrode 40 is a negative electrode.

[0070] The third pole 50 is used for external high voltage power supply to perform thermal runaway triggering experiments.

[0071] The contact member 60 is disposed between the first pole piece and the second pole piece and is insulated from one of the first pole piece and the second pole piece. The contact member 60 is used to trigger thermal runaway at a selected position.

[0072] One end of the lead-out member 70 is connected to the contact member 60, and the other end is connected to the third pole 50. The lead-out member 70 is used to connect the contact member 60 to an external power source in a conductive manner.

[0073] When triggering thermal runaway, the contact piece 60 is insulated and contacted with the first pole piece or the second pole piece as needed, and then the two ends of the high-voltage power supply are respectively connected to the third pole 50, the second pole 40 or the first pole 30, the power supply parameters of the high-voltage power supply are set, and the circuit is closed to conduct the experiment; after the thermal runaway is triggered, the circuit is disconnected to end the thermal runaway trigger.

[0074] Depending on the research content, the contact 60 can be insulated from one of the pole pieces in the pole core 20. The power supply parameters of the high-voltage power supply can be set according to the research content to trigger thermal runaway, thereby generating a high-voltage arc on the pole piece insulated from the contact 60, inducing thermal runaway. The mechanism and phenomenon of thermal runaway triggered by this battery cell 100 are very close to those of real internal short-circuit thermal runaway. By adjusting the power supply parameters of the high-voltage power supply and selecting the position of the insulated contact pole piece of the contact 60, thermal runaway experiments can be performed at different positions in the battery cell 100. This battery cell 100 can be widely used in thermal runaway, heat diffusion mechanism research, protective material selection, safety evaluation, and other aspects.

[0075] Battery cell 100 has the advantages of low input energy, heat generation close to the actual internal heat generation, good consistency, and no impact on the assembly of battery cell 100. It can be applied in failure analysis, thermal diffusion research, and protective material selection.

[0076] In one possible implementation, the housing 10 includes a shell 11 and a cover 12, wherein the cover 12 is disposed on the shell 11. The pole core 20, the contact member 60, and the lead member 70 are respectively disposed in the shell 11, and the first pole 30, the second pole 40, and the third pole 50 are respectively disposed on the cover 12.

[0077] In a possible implementation, the contact member 60 is disposed in the pole core 20 , and its extension direction is parallel to the plane where the cover plate 12 is located.

[0078] One side of the lead-out member 70 is connected to the contact member 60 , and the other side thereof extends toward the cover plate 12 on which the third pole 50 is provided, so as to be connected to the third pole 50 .

[0079] like Figure 2 As shown, in one possible implementation, the cover plate 12 includes a first cover plate 121 and a second cover plate 122. The first cover plate 121 and the second cover plate 122 are disposed on opposite sides of the housing 11. The first pole 30 is disposed on the first cover plate 121. The second pole 40 is disposed on the second cover plate 122. The third pole 50 is disposed on the first cover plate 121 or the second cover plate 122, or on the housing 11.

[0080] In a possible implementation, the contact member 60 is a metal member, and the melting point of the contact member 60 is higher than 400° C.

[0081] In a possible implementation, the contact member 60 is made of metal materials such as aluminum, nickel, copper, iron, and tungsten.

[0082] In a possible implementation, the thickness of the contact 60 is less than 150 μm.

[0083] When the thickness of the contact member 60 is greater than or equal to 150 μm, when the contact member 60 is provided in the pole core 20 , the performance of the pole core 20 is greatly affected, which may easily lead to the experimental results being inconsistent with the actual situation.

[0084] In one possible implementation, the contact member 60 includes an electrode portion 61 and an extraction portion 62. The electrode portion 61 is located on the side of the contact member 60 away from the extraction member 70. The extraction portion 62 is located on the side of the contact member 60 closer to the extraction member 70. The electrode portion 61 is the portion of the contact member 60 that is insulated from the electrode, while the extraction portion 62 is the portion that connects the contact member 60 to the extraction member 70.

[0085] In this case, the contact 60 is insulated from the electrode. Specifically, the electrode portion 61 must meet the requirements of electronic insulation and ionic conductivity. The lead portion 62 only needs to be insulated. The lead portion 62 mainly serves as a current guide, but because it is located inside the battery cell, it must be insulated to avoid failure. The electrode portion 61 generates high-voltage arcing with the electrode through the electrolyte, which can induce thermal runaway of the battery. Therefore, the electrode portion 61 must meet the requirements of electronic insulation and ionic conductivity.

[0086] In a possible implementation, the electrode portion 61 is a metal sheet or a metal coil.

[0087] In a possible implementation, the lead-out portion 62 is a metal sheet or a metal wire.

[0088] In a possible implementation, the contact member 60 is one of a metal wire, a metal coil, a metal sheet, a combination of a metal wire and a metal coil, and a combination of a metal wire and a metal sheet.

[0089] In a possible implementation, an insulating layer is provided on the surface of the electrode portion 61 .

[0090] In some embodiments, the insulating layer is made of insulating materials such as porous polypropylene (PP) and porous polyethylene, thereby facilitating electronic insulation and ion conduction.

[0091] A layer of insulating material such as polyimide (PI) or polyethylene terephthalate (PET) is laminated on the surface of the remaining portion of the contact member 60 .

[0092] When the contact piece 60 adopts a metal wire structure, the head 10mm-30mm of the metal wire entering the pole core 20 is coated with a layer of 20μm-40μm porous polypropylene (PP), and the surface of the remaining part of the metal wire entering the pole core 20 is pressed with a layer of 20μm-40μm polyimide (PI).

[0093] The contact area between the electrode portion 61 coated with porous PP and the electrode piece is S1 (unit: mm 2 ), if thermal runaway is to be triggered stably, the voltage V1 (unit: V) applied by the external high-voltage power supply and the value of S1 should satisfy: 300*S1≤V1≤5000*S1.

[0094] If the voltage V1 applied by the high-voltage power supply is too low, thermal runaway of the battery cell cannot be triggered. If the applied voltage V1 is too high, the thermal runaway phenomenon will be too severe (taking lithium iron phosphate as an example, the expected phenomenon level after thermal runaway is EUCAR standard L4 level. If the applied voltage is too low, the phenomenon level will be L1-L3 level. If the applied voltage is too high, the phenomenon level will be L5-L7 level). The preferred V1 range is 400V-700V.

[0095] When the contact piece 60 adopts a metal sheet structure, the head 10mm-30mm of the metal sheet entering the pole core 20 is coated with a layer of 10μm-30μm porous polypropylene (PP), and the surface of the remaining part of the metal sheet entering the pole core 20 is pressed with a layer of 10μm-30μm polyimide (PI).

[0096] The contact area between the electrode portion 61 coated with porous PP and the electrode piece is S2 (unit: mm 2 ), if thermal runaway is to be triggered stably, the voltage V2 (unit: V) applied by the external high-voltage power supply and the value of S2 should satisfy: 0.7*S2≤V2≤2*S2.

[0097] If the voltage V2 applied by the high-voltage power supply is too low, thermal runaway of the battery cell cannot be triggered. If the applied voltage V2 is too high, the thermal runaway phenomenon will be too severe. The preferred range of V2 is 60V-150V.

[0098] When the contact piece 60 adopts a metal wire + metal coil structure, the metal coil entering the pole core 20, that is, the surface of the electrode part 61 is coated with a layer of 20μm-40μm porous polypropylene (PP), and the surface of the metal wire entering the pole core 20 is pressed with a layer of 10μm-30μm polyimide (PI).

[0099] Among them, the contact area between the metal coil and the pole piece is S3 (unit: mm 2 ), if thermal runaway is to be triggered stably, the voltage V3 (unit: V) applied by the external high-voltage power supply and the value of S3 should satisfy: 0.3*S3≤V3≤8*S3.

[0100] If the voltage V3 applied by the high-voltage power supply is too low, thermal runaway of the battery cell cannot be triggered. If the applied voltage V3 is too high, the thermal runaway phenomenon will be too severe. The preferred range of V3 is 60V-120V.

[0101] When the contact piece 60 adopts a metal wire + metal sheet structure, the head 10mm-30mm of the metal sheet entering the pole core 20 is coated with a layer of 10μm-30μm porous polypropylene (PP), and the surface of the remaining metal sheet and metal wire entering the pole core 20 is coated with a layer of 10μm-30μm polyimide (PI).

[0102] The area of the electrode portion 61 coated with porous PP is S4 (unit: mm 2 ), if thermal runaway is to be triggered stably, the voltage V4 (unit: V) applied by the external high-voltage power supply and the value of S4 should satisfy: 0.7*S4≤V4≤2*S4.

[0103] If the voltage V4 applied by the high-voltage power supply is too low, thermal runaway of the battery cell cannot be triggered. If the applied voltage V4 is too high, the thermal runaway phenomenon will be too severe. The preferred range of V4 is 60-150V.

[0104] Furthermore, in the above embodiment, the specific areas of S1-S4 can be determined by non-destructively inspecting the internal metal sheet of the battery using CT and comparing the metal sheet area with a predetermined area range. Specifically, the area of the contact covered by the porous PP layer can be used as the effective area of the electrode portion.

[0105] Preferably, the contact member 60 adopts a metal wire + metal coil or metal wire + metal sheet structure. The side of the contact member 60 away from the lead member 70 is the metal coil or metal sheet, while the side close to the lead member 70 is the metal wire. That is, the electrode portion 61 of the contact member 60 is a metal sheet or metal coil, and the lead portion 62 is a metal wire.

[0106] Electrode 61 is constructed using metal sheets, metal coils, or other structures due to its large cross-sectional area. The area of electrode 61, or the area of the contact 60 head, correlates to the voltage applied by the high-voltage power supply. The smaller the cross-sectional area, the higher the voltage required from the high-voltage power supply during thermal runaway testing. Using a metal wire structure for electrode 61 requires a very high voltage output from the high-voltage power supply to trigger thermal runaway. Furthermore, the resulting thermal runaway phenomenon is too intense, significantly deviating from the actual phenomenon of internal short-circuit thermal runaway.

[0107] The lead-out portion 62 is made of a metal wire structure because its cross-sectional area is small, and the contact member 60 is arranged between the first pole piece and the second pole piece, which will affect the insertion and extraction of lithium ions between the first pole piece and the second pole piece during normal use. Therefore, a metal wire with a smaller cross-sectional area is selected to reduce the impact.

[0108] Table 1 shows the area of electrode portion 61, the EUCAR test phenomenon level, and the maximum cell surface temperature when contact 60 uses a metal wire + metal sheet structure. During the experiment, contact 60 was placed on the surface of the negative electrode sheet, with the low-voltage terminal of the high-voltage power supply contacting the third electrode 50 and the high-voltage terminal contacting the positive electrode.

[0109] Table 1 Experimental results of metal wire + metal sheet structure

[0110]

[0111] It can be seen from Table 1 that: when the area of the electrode portion 61 is too small and the voltage of the high-voltage power supply is too low, thermal runaway cannot be triggered; when the area of the electrode portion 61 is constant, the higher the voltage of the high-voltage power supply, the higher the level of the thermal runaway phenomenon.

[0112] Therefore, in order to achieve a smaller area of the electrode portion 61 in the contact 60 to stably trigger thermal runaway and control the thermal runaway phenomenon level to L4, it is necessary to select a suitable area of the electrode portion 61 and a voltage range of the high-voltage power supply.

[0113] In one embodiment, the contact 60 is a combination of a nickel sheet and a copper wire. During the experiment, the contact 60 contacts the surface of the negative electrode sheet, the low-voltage end of the high-voltage power supply contacts the third pole 50, and the high-voltage end contacts the positive pole. The length of the nickel sheet is 10 mm, the width is 5 mm, and the thickness is 0.08 mm. The diameter of the copper wire is 0.08 mm. The surface of the nickel sheet is coated with a layer of 15 μm porous polypropylene (PP), and the surface of the copper wire is coated with a layer of 15 μm polyimide (PI). The voltage of the high-voltage power supply used in the thermal runaway triggering process is 100 V, and the protection current is 25 A.

[0114] In one possible implementation, the pole core 20 includes a plurality of first pole pieces and a second pole piece, which are stacked on each other. The contact piece 60 is arranged on one layer of the first pole piece or the second pole piece inside the pole core 20. When stacked, the remaining pole pieces restrict the contact piece 60. After the pole core 20 is hot-pressed, the contact piece 60 is clamped and fixed inside the pole core 20.

[0115] The position of the contact member 60 on the first pole piece or the second pole piece is adjusted according to the position requirement for triggering thermal runaway, and different lead-out methods of the contact member 60 are selected according to different types of the pole core 20 .

[0116] In one possible implementation, the first electrode is a positive electrode, the second electrode is a negative electrode, and the contact 60 is insulated from the second electrode.

[0117] Since the voltage required to stably trigger thermal runaway is different when the contact member 60 is insulated from contact with the first electrode or the second electrode, the voltage required to trigger thermal runaway is smaller when the contact member 60 is insulated from contact with the negative electrode.

[0118] When the contact 60 is insulated and in contact with the positive electrode, the high voltage terminal of the high voltage power supply is connected to the third pole 50, and the low voltage terminal of the high voltage power supply is connected to the negative pole. When the contact 60 is insulated and in contact with the negative electrode, the high voltage terminal of the high voltage power supply is connected to the positive pole, and the low voltage terminal of the high voltage power supply is connected to the third pole 50.

[0119] Specifically, the first electrode is a positive electrode, the second electrode is a negative electrode, and the voltage applied by the high-voltage power supply when the contact member 60 is insulated contact with the second electrode is lower than the voltage applied by the high-voltage power supply when the contact member 60 is insulated contact with the first electrode.

[0120] Table 2 shows the data of the voltage of the high-voltage power supply, the EUCAR experimental phenomenon level, and the maximum temperature of the cell surface when the contact member 60 contacts the positive electrode sheet and the negative electrode sheet respectively.

[0121] Table 2 Experimental results of the contact 60 insulated contact with the positive and negative electrodes

[0122]

[0123] From Table 2, we can see that: at 100mm 2 Under the electrode area, when the contact member 60 is insulated and contacts the positive electrode sheet, a voltage of 150V is required to stably trigger the thermal runaway of the battery cell. When the contact member 60 is insulated and contacts the negative electrode sheet, a voltage of 100V is required to stably trigger the thermal runaway of the battery cell.

[0124] In a possible implementation, the housing 11 includes a side plate 111 . The lead-out member 70 is provided on the side plate 111 .

[0125] In a possible implementation, the side plate 111 is made of insulating material.

[0126] In a possible implementation, the side plate 111 is provided with an avoidance cavity, and the avoidance cavity extends toward the cover plate 12. The lead-out member 70 is provided in the avoidance cavity.

[0127] The provision of the avoidance cavity can prevent the lead-out member 70 from contacting the side surface of the pole core 20 when being led out from the side plate to the cover plate 12 .

[0128] If the side plate 111 is not provided with an escape cavity, when the lead-out member 70 is led out from the side of the side plate 111 close to the pole core 20, it may cause the lead-out member 70 to contact the side of the pole piece, causing an uncontrollable internal short circuit. For a battery cell 100 whose housing 11 is not charged, if the lead-out member 70 is led out from the side of the side plate 111 away from the pole core 20, it may cause the housing 11 to become charged, resulting in electrochemical corrosion. For a battery cell 100 whose housing 11 is charged, if the lead-out member 70 is led out from the side of the side plate 111 away from the pole core 20, it may cause the battery cell 100 to short-circuit through the housing 11.

[0129] In a possible implementation, the avoidance cavity is provided in the middle portion of the side plate 111 .

[0130] like Figure 3 As shown, in a possible implementation, the lead-out member 70 is a metal wire.

[0131] When the lead-out member 70 is a metal wire, the contact member 60 is preferably a metal wire + metal coil or a metal wire + metal sheet. In this case, the lead-out portion 62 of the contact member 60 can have the same structure as the lead-out member 70. The lead-out member 70 is provided on the side plate 111. One end near the electrode portion 61 is bent directly 90° to connect to the electrode portion 61 of the metal coil or metal sheet structure. The other end is bent directly 90° to be welded to the third pole 50.

[0132] like Figure 4 As shown, in a possible implementation, the lead-out member 70 is made of a metal sheet.

[0133] When the lead-out piece 70 is a metal sheet, the contact piece 60 is preferably a metal sheet structure. In this case, the lead-out portion 62 of the contact piece 60 can be connected to the lead-out piece 70 through a transition surface. The lead-out piece 70 is provided on the side plate 111, and the contact piece 60 is provided in the pole core 20, and the lead-out portion 62 of the contact piece 60 is bent 90° near the side plate 111, so that this part of the metal sheet is in a parallel position with the lead-out piece 70 on the side plate 111, forming a connection surface with a larger area. In this way, the area of the connection between the contact piece 60 and the lead-out piece 70 is larger, and a stable electrical connection can be achieved. At the same time, after the electrical connection is achieved, the connection needs to be insulated to prevent it from contacting the side of the pole piece. The other end of the lead-out piece 70 is directly bent 90° and welded to the third pole 50.

[0134] like Figure 5 As shown, in a possible implementation, the third pole 50 includes a conductive pole 51 and an insulating ring 52 . The conductive pole 51 is disposed on the housing 10 . The insulating ring 52 connects the conductive pole 51 and the housing 10 . The lead-out piece 70 is connected to the conductive pole 51 .

[0135] Specifically, the conductive pillar 51 is passed through the cover plate 12 , the insulating ring 52 insulates and connects the conductive pillar 51 to the cover plate 12 , and the lead-out member 70 is connected to the conductive pillar 51 from the inner side of the cover plate 12 .

[0136] In a possible implementation, the insulating ring 52 is a ceramic ring that is sleeved on the conductive pillar 51 and disposed on the cover plate 12 to insulate the conductive pillar 51 from the cover plate 12 .

[0137] In one possible implementation, the conductive post 51 is a copper-aluminum composite pole, with the portion located inside the cover 12 being a copper bar and the portion located outside the cover 12 being an aluminum bar. The lead-out member 70 is connected to the copper bar inside the cover 12.

[0138] The aluminum bar of the conductive pillar 51 is used to connect to an external high-voltage power source, so that the energized state of the contact 60 is controlled through the conductive pillar 51 .

[0139] In a possible implementation, the third pole 50 further includes a sealing ring 53 , which is used to seal the gap between the insulating ring 52 and the housing 10 , so as to seal the insulating ring 52 on the housing 10 .

[0140] Specifically, the sealing ring 53 is sleeved on the outside of the insulating ring 52, thereby sealing the hole through which the conductive column 51 passes through the cover plate 12, thereby isolating the inside and outside of the battery cell 100, preventing water and oxygen outside the battery cell 100 from entering the inside of the battery cell 100, and preventing the electrolyte inside the battery cell 100 from leaking.

[0141] In a possible implementation, the sealing ring 53 is made of rubber.

[0142] In one possible implementation, the third pole 50 is disposed on the same cover plate 12 as the first pole 30 or the second pole 40. On the side of the cover plate 12 close to the housing 11, a gap exists between the third pole 50 and the connection between the first pole 30 and the first electrode piece, or the connection between the second pole 40 and the second electrode piece. In other words, a gap exists between the copper bar inside the conductive post 51 and the welding location between the first pole 30 and the tab on the first electrode piece, or the welding location between the second pole 40 and the tab on the second electrode piece.

[0143] Specifically, a certain electrical gap, L, must be maintained between the copper bar inside the third electrode 50 and the tabs inside the positive and negative electrodes to prevent short circuits or arcing when high voltage is applied. To prevent short circuits, L must be greater than 0mm; to prevent arcing under high voltage, L must be greater than 0.1V5mm, where V5 is the applied voltage in volts. Therefore, considering both L and V5, the following values must be met: L>0.1V5mm.

[0144] The present invention also provides a method for simulating thermal runaway, comprising the following steps:

[0145] Providing a high voltage power supply and the battery cell 100;

[0146] Connect one end of the high-voltage power supply to the third pole 50, and connect the other end of the high-voltage power supply to the second pole 40 or the first pole 30;

[0147] Set the power parameters of the high voltage power supply and close the loop;

[0148] After thermal runaway is triggered, the circuit is opened.

[0149] The high-voltage power supply may be a device that can provide high voltage, or a battery assembly or battery pack.

[0150] Preferably, the range of the high voltage power supply is 0-1000V.

[0151] Specifically, one end of the high-voltage power supply is connected to the positive electrode or the negative electrode of the pole core 20 , and the other end is connected to the third pole 50 .

[0152] Preferably, the contact member 60 is insulated from and in contact with the negative electrode sheet, the high voltage end of the high voltage power supply is connected to the positive electrode of the pole core 20 , and the low voltage end of the high voltage power supply is connected to the third pole 50 .

[0153] Set the power supply parameters of the high-voltage power supply: select the appropriate voltage range and connection method based on the different electrode structures and areas. For example, set the appropriate voltage, current, and time recording interval.

[0154] The battery cell 100 provided in the embodiment of the present application includes a housing 10, a pole core 20, a first pole post 30, a second pole post 40, a third pole post 50, a contact member 60, and a lead-out member 70. The pole core 20 is disposed in the housing 10 and includes a first pole piece and a second pole piece; the first pole post 30 is connected to the first pole piece; the second pole post 40 is connected to the second pole piece; the contact member 60 is disposed in the pole core 20 and is in insulated contact with one of the first and second pole pieces; the third pole post 50 is disposed on the housing 10; and the lead-out member 70 is disposed in the housing 10, with one end of the lead-out member 70 connected to the contact member 60 and the other end connected to the third pole post 50.

[0155] By providing a third pole 50 on the housing 10, providing a contact 60 on one of the pole pieces in the pole core 20, and connecting the contact 60 to the third pole 50 via a lead 70, the contact 60 can be placed in insulated contact with one of the pole pieces in the pole core 20, depending on the research content. By applying a high-voltage power supply, the third pole 50 and the pole corresponding to the pole piece not insulated from the contact 60 are connected to the two ends of the high-voltage power supply. The power supply parameters of the high-voltage power supply are set according to the research content to trigger thermal runaway, thereby generating a high-voltage arc on the pole piece insulated from the contact 60, inducing thermal runaway. The mechanism and phenomenon of thermal runaway triggered by this battery cell 100 are very similar to those of real internal short-circuit thermal runaway. By adjusting the power supply parameters of the high-voltage power supply and selecting the insulated contact position of the contact 60, thermal runaway experiments can be conducted at different locations in the battery cell 100. This battery cell 100 can be widely used in thermal runaway and heat diffusion mechanism research, protective material selection, safety evaluation, and other aspects.

[0156] In addition, an embodiment of the present application also provides a thermal runaway testing system, including a high-voltage power supply and the battery cell 100 described in any of the above embodiments, where the high-voltage power supply is used to provide electrical energy to the battery cell 100.

[0157] The specific structure, working principle and function of the battery cell 100 have been described in detail in the aforementioned embodiments and will not be repeated here.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: Housing (10); A pole core (20), the pole core (20) being disposed in the housing (10), the pole core (20) comprising a first pole piece and a second pole piece; a first pole (30), the first pole (30) being provided on the housing (10) and connected to the first pole piece; a second pole (40), the second pole (40) being provided on the housing (10) and connected to the second pole piece; A third pole (50), the third pole (50) being provided on the housing (10); a contact member (60), the contact member (60) being disposed between the first pole piece and the second pole piece and being in insulated contact with one of the first pole piece and the second pole piece; A lead-out piece (70) is provided in the housing (10), and one end of the lead-out piece (70) is connected to the contact piece (60), and the other end is connected to the third pole (50).

2. The battery cell according to claim 1, characterized in that The contact piece (60) is a metal piece, and the melting point of the contact piece (60) is higher than 400°C.

3. The battery cell according to claim 1, characterized in that The contact member (60) comprises an electrode portion (61) and a lead portion (62), wherein the electrode portion (61) is located on a side of the contact member (60) away from the lead portion (70), and the lead portion (62) is located on a side of the contact member (60) close to the lead portion (70).

4. The battery cell according to claim 3, characterized in that The electrode portion (61) is a metal sheet or a metal coil.

5. The battery cell according to claim 3, characterized in that: The lead-out portion (62) is a metal wire.

6. The battery cell according to claim 3, characterized in that An insulating layer is provided on the surface of the electrode portion (61).

7. The battery cell according to any one of claims 1 to 6, characterized in that: The contact member (60) is one of a metal wire, a metal coil, a metal sheet, a combination of a metal wire and a metal coil, and a combination of a metal wire and a metal sheet.

8. The battery cell according to any one of claims 1 to 6, characterized in that: The thickness of the contact element (60) is less than 150 μm.

9. The battery cell according to any one of claims 1 to 6, characterized in that: The first pole piece is a positive pole piece, the second pole piece is a negative pole piece, and the contact member (60) is in insulating contact with the second pole piece.

10. The battery cell according to any one of claims 1 to 6, characterized in that: The housing (10) comprises a shell (11) and a cover plate (12), wherein the cover plate (12) is covered on the shell (11), the pole core (20) is arranged in the shell (11), the third pole (50) is arranged on the cover plate (12), the contact member (60) is arranged in the pole core (20), and the extension direction is parallel to the plane where the cover plate (12) is located, and the lead member (70) is arranged on the shell (11), and one side is connected to the contact member (60), and the other side extends toward the cover plate (12) to be connected to the third pole (50).

11. The battery cell according to claim 10, characterized in that: The housing (11) comprises a side plate (111), and the lead-out member (70) is arranged on the side plate (111).

12. The battery cell according to claim 11, characterized in that The side plate (111) is provided with a avoidance cavity, the extension direction of the avoidance cavity is toward the cover plate (12), and the lead-out member (70) is provided in the avoidance cavity.

13. The battery cell according to claim 11, characterized in that The side plate (111) is an insulating member.

14. The battery cell according to claim 10, characterized in that The first pole (30) or the second pole (40) is provided on the cover plate (12), and a gap exists between the third pole (50) and the first pole (30) or the second pole (40).

15. The battery cell according to any one of claims 1 to 6, characterized in that: The lead-out member (70) is a metal wire or a metal sheet.

16. The battery cell according to any one of claims 1 to 6, characterized in that: The third pole (50) comprises an insulating ring (52) and a conductive pole (51), the conductive pole (51) is provided on the housing (10), the insulating ring (52) connects the conductive pole (51) and the housing (10), and the lead-out piece (70) is connected to the conductive pole (51).

17. The battery cell according to claim 16, characterized in that: The third pole (50) further comprises a sealing ring (53), and the sealing ring (53) is used to seal the gap between the insulating ring (52) and the housing (10).

18. A thermal runaway test system, characterized in that: It comprises a high-voltage power supply and a battery cell (100) according to any one of claims 1 to 17, wherein one end of the high-voltage power supply is connected to the third pole (50), and the other end is connected to the second pole (40) or the first pole (30).

19. The thermal runaway testing system according to claim 18, wherein: The contact member (60) is a metal wire, the insulating contact area between the contact member (60) and the first pole piece or the second pole piece is S1, the voltage applied by the high-voltage power supply is V1, S1 and V1 satisfy: 300*S1≤V1≤5000*S1, wherein the unit of V1 is V and the unit of S1 is mm 2 .

20. The thermal runaway testing system according to claim 18, wherein: The contact member (60) is a metal sheet, the contact area between the contact member (60) and the first pole piece or the second pole piece is S2, the voltage applied by the high-voltage power supply is V2, S2 and V2 satisfy: 0.7*S2≤V2≤2*S2, wherein the unit of V2 is V and the unit of S2 is mm 2 .

21. The thermal runaway testing system according to claim 18, wherein: The contact member (60) is a combination of a metal wire and a metal coil. The contact member (60) is insulated from the first pole piece or the second pole piece through the metal coil. The contact area is S3. The voltage applied by the high-voltage power supply is V3. S3 and V3 satisfy the following conditions: 0.3*S3≤V3≤8*S3, wherein the unit of V3 is V and the unit of S3 is mm. 2 .

22. The thermal runaway testing system according to claim 18, wherein: The contact member (60) is a combination of a metal wire and a metal sheet. The contact member (60) is insulated from the first pole piece or the second pole piece through the metal sheet. The contact area is S4. The voltage applied by the high-voltage power supply is V4. S4 and V4 satisfy the following conditions: 0.7*S4≤V4≤2*S4, wherein the unit of V4 is V and the unit of S4 is mm. 2 .

23. The thermal runaway testing system according to claim 18, wherein: The first pole piece is a positive pole piece, the second pole piece is a negative pole piece, and the voltage applied by the high-voltage power supply when the contact piece (60) is in insulated contact with the second pole piece is lower than the voltage applied by the high-voltage power supply when the contact piece (60) is in insulated contact with the first pole piece.

24. The thermal runaway testing system according to claim 18, wherein: The first pole (30) or the second pole (40) and the third pole (50) are arranged on the same cover plate (12); on the side of the cover plate (12) close to the shell (11), there is a gap L between the connection position of the third pole (50) and the first pole (30) and the first pole piece, or there is a gap L between the connection position of the third pole (50) and the second pole (40) and the second pole piece; the voltage applied by the high-voltage power supply is V5 and L satisfies: L>0.1V5, wherein the unit of V5 is V and the unit of L is mm.

Images