Sodium ion battery sodium precipitation detection device and detection method

Abstract

The invention discloses a sodium ion battery sodium precipitation detection device and detection method, and relates to the technical field of sodium ion battery sodium precipitation detection. The sodium ion battery sodium precipitation detection device comprises a flexible insulating part, a fixing part, a pressure applying part and an induction part, the flexible insulating part wraps the surface of a roll core in a sealed mode, and a battery cell is defined and formed; the fixing piece is provided with an accommodating space, and the battery cell is arranged in the accommodating space; the pressure applying piece is used for applying pressure with preset magnitude to the battery cell; the sensing piece is in contact with the outer surface of the battery cell and is used for sensing the pressure change of the surface of the battery cell so as to judge the volume change of the battery cell. According to the sodium ion battery sodium precipitation detection device provided by the invention, the sensing piece is arranged outside the battery cell, the pressure change of the battery cell during charging and discharging is monitored from the outside of the battery cell, whether the expansion pressure of the battery cell is reversible is accurately judged, and whether the sodium ion battery has a sodium precipitation phenomenon is judged.

Description

Technical Field

[0001] The present application relates to the technical field of sodium ion battery sodium precipitation detection, and in particular to a sodium ion battery sodium precipitation detection device and detection method. Background Art

[0002] When sodium-ion batteries are charged at high rates, in low temperature environments, and at high states of charge, the kinetic characteristics of sodium embedding in the negative electrode are severely restricted. More sodium ions are easily deposited on the surface of the negative electrode and precipitate metallic sodium, causing rapid decay of the battery capacity, shortened battery life, and even causing many problems such as thermal runaway safety hazards.

[0003] The core of existing cylindrical batteries is usually confined in a hard steel shell, and changes in the volume of the core inside the steel shell cannot be detected from the outside. Summary of the invention

[0004] In view of this, the present application provides a sodium ion battery sodium precipitation detection device and detection method, the purpose of which is to solve one of the technical problems in the prior art.

[0005] To achieve the above objectives, the technical solutions adopted in this application are as follows:

[0006] In a first aspect, an embodiment of the present application provides a sodium ion battery sodium precipitation detection device, comprising:

[0007] A flexible insulating member is sealed and coated on the surface of the winding core to define a battery core;

[0008] A fixing member having a receiving space, wherein the battery cell is arranged in the receiving space;

[0009] A pressure-applying member, used to apply a preset pressure to the battery cell;

[0010] The sensing element is in contact with the outer surface of the battery cell and is used to sense the pressure change on the surface of the battery cell, thereby determining the volume change of the battery cell.

[0011] In one embodiment of the first aspect, the flexible insulating member is made of an aluminum-plastic film, a multi-layer co-extruded composite film or an aluminum-plated film composite material;

[0012] The positive electrode tab and the negative electrode tab of the winding core are respectively exposed from the flexible insulating member;

[0013] Sodium ion battery electrolyte is also filled between the flexible insulating member and the winding core.

[0014] In one embodiment of the first aspect, the fixing member includes at least two clamps, the at least two clamps are surrounded and attached to the outer side of the battery core, and the induction member is pressed between the fixing member and the battery core;

[0015] The pressure-applying member includes at least one clamp, which is sleeved on the outside of the fixing member. The pressure applied to the battery cell can be adjusted by loosening or tightening the clamp.

[0016] In one embodiment of the first aspect, the fixing member further has a first opening and a second opening that are arranged opposite to each other, and the first opening, the receiving space and the second opening are connected in sequence.

[0017] In one embodiment of the first aspect, the sensing element includes a sensing terminal and a lead, the sensing terminal is arranged in the receiving space and attached to the surface of the flexible insulating element, the lead is connected to the sensing terminal and is passed through the first opening or the second opening, the positive electrode tab of the battery cell is passed through the first opening, and the negative electrode tab of the battery cell is passed through the second opening.

[0018] In a second aspect, the present application further provides a sodium ion battery sodium precipitation detection method, which is implemented using the sodium ion battery sodium precipitation detection device in any of the above embodiments and includes:

[0019] Get the roll core;

[0020] The flexible insulating member is sealed and packaged on the surface of the detection battery cell to form a battery cell;

[0021] Perform aging treatment on the battery cells;

[0022] Assemble the induction component, the fixing component and the pressure component on the battery cell;

[0023] Applying a preset pressure to the battery cell by means of a pressure applying member;

[0024] The battery cell is charged and discharged multiple times, and the pressure change on the surface of the battery cell is detected by the sensor to determine the volume change of the battery cell.

[0025] In one of the embodiments of the second aspect, the positive electrode tab and the negative electrode tab of the winding core are lengthened, and then the flexible insulating member is wrapped on the surface of the winding core, and the positive electrode tab and the negative electrode tab of the winding core are exposed from the flexible insulating member, and then the winding core and the flexible insulating member are sealed and packaged.

[0026] In one embodiment of the second aspect, a through hole is opened in the sealed flexible insulating member, and a sodium ion battery electrolyte is injected, and then the flexible insulating member is vacuum-sealed and left to stand for 12 to 36 hours.

[0027] In one embodiment of the second aspect, after the battery cell is fully charged, it is left to stand at 40° C. to 50° C. for 0.5 to 2 days, and then the battery cell is discharged to a preset power to complete the aging process.

[0028] In one embodiment of the second aspect, the pressure applied by the pressure-applying member to the battery cell is 30 kPa to 45 kPa.

[0029] Compared with the prior art, the beneficial effects of the present application are as follows: the present application proposes a sodium ion battery sodium precipitation detection device, including a flexible insulating member, a fixing member, a pressure member and a sensing member, wherein the flexible insulating member is sealed and coated on the surface of the winding core and defines a battery cell; the fixing member has a receiving space, and the battery cell is arranged in the receiving space; the pressure member is used to apply a preset pressure to the battery cell; the sensing member contacts the outer surface of the battery cell and is used to sense the pressure change on the surface of the battery cell, thereby judging the volume change of the battery cell. The battery cell is encapsulated with a flexible insulating member instead of a traditional steel shell, and the sensing member is installed on the outside of the battery cell, which solves the problem that the volume change of the cylindrical battery is difficult to monitor from the outside of the battery. The pressure change of the battery cell during charging and discharging is monitored by the sensing member, and the expansion pressure of the battery cell is accurately judged to be reversible, and whether the sodium ion battery has sodium precipitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of the structure of a sodium ion battery sodium precipitation detection device in some embodiments of the present application is shown;

[0032] Figure 2 A schematic diagram of the exploded structure of a sodium ion battery sodium precipitation detection device in some embodiments of the present application is shown;

[0033] Figure 3 A flow chart of a sodium ion battery sodium precipitation detection method in some embodiments of the present application is shown;

[0034] Figure 4 The pressure variation of the battery cell of Example 1 during 1C charge and discharge process is shown;

[0035] Figure 5 The pressure change of the battery cell of Example 2 during 1C charge and discharge process is shown;

[0036] Figure 6 The surface condition of the electrode of the battery cell of Example 1 after 30 cycles of charge and discharge is shown;

[0037] Figure 7 The surface condition of the electrode of the battery cell of Example 2 after 30 cycles of charge and discharge is shown.

[0038] Explanation of main component symbols: 100 - sodium ion battery sodium analysis detection device; 110 - battery cell; 120 - fixing piece; 121 - clamp; 122 - receiving space; 123 - first opening; 124 - second opening; 130 - pressure piece; 140 - sensing piece; 141 - sensing terminal; 142 - lead wire. DETAILED DESCRIPTION

[0039] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0040] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0042] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] like Figure 1 and Figure 2 As shown, an embodiment of the present application provides a sodium ion battery sodium precipitation detection device 100, which is mainly used to detect whether sodium precipitation occurs in a sodium ion battery.

[0045] The sodium ion battery sodium precipitation detection device 100 includes a flexible insulating member, a fixing member 120 , a pressure member 130 and a sensing member 140 .

[0046] At present, the core of cylindrical batteries is usually bound in a hard steel shell, and the volume change inside the steel shell cannot be detected from the outside. In addition, placing the sensor inside the core for detection will easily cause the sensor to corrode and reduce the space utilization rate inside the steel shell, which will have a certain impact on the battery.

[0047] In view of the above problems, the flexible insulating member of the present application is sealed and coated on the surface of the winding core, and is limited to form a battery cell 110, so that the volume change of the winding core can be transmitted to the flexible insulating member. The fixing member 120 has a receiving space 122, and the battery cell 110 is arranged in the receiving space 122; the pressure member 130 is used to apply a preset pressure to the battery cell 110; the sensing member 140 is in contact with the outer surface of the battery cell 110, and is used to sense the pressure change on the surface of the battery cell 110, so as to determine the volume change of the battery cell 110.

[0048] A flexible insulating part is used instead of a traditional steel shell to package the winding core, and the sensing part 140 is installed on the outside of the battery cell 110, which solves the problem that the volume change of the cylindrical battery is difficult to monitor from the outside of the battery. The sensing part 140 monitors the pressure change of the battery cell 110 during charging and discharging, accurately determines whether the expansion pressure of the battery cell 110 is reversible, and determines whether sodium precipitation occurs in the sodium-ion battery.

[0049] It should be understood that sodium-ion batteries will produce volume changes during the charging and discharging process, which mainly comes from the volume changes of the negative electrode sheets in the winding core. The negative electrode sheets will expand in volume due to the embedding of sodium ions during the charging process, and the negative electrode materials will shrink during the discharge process. The volume changes caused by the normal sodium removal-sodium embedding process are reversible. If sodium precipitation occurs, the negative electrode sheets will become irreversibly thickened, and the sodium precipitation phenomenon can be determined by detecting the irreversible expansion stress.

[0050] In some embodiments, the flexible insulating member is made of aluminum-plastic film, multi-layer co-extruded composite film or aluminum-plated film composite material.

[0051] Among them, the aluminum-plastic film has excellent oxygen and nitrogen barrier properties, which can effectively prevent external gases from entering the battery cell 110 and extend the life of the battery cell 110. At the same time, the aluminum-plastic film has a strong barrier effect on water vapor and is particularly suitable for packaging requirements in humid environments.

[0052] In some embodiments, the positive electrode tab and the negative electrode tab of the winding core are respectively exposed from the flexible insulating member, so as to facilitate the connection of the battery cell 110 with an external device and improve the charging and discharging efficiency of the battery cell 110 .

[0053] In one embodiment, the positive electrode tab and the negative electrode tab are lengthened to 40 mm.

[0054] In some embodiments, sodium ion battery electrolyte is also filled between the flexible insulating member and the winding core as a buffer liquid to protect the winding core structure within the flexible insulating member.

[0055] In addition, by filling the flexible sealing member with sodium ion battery electrolyte, both the flexible insulating member and the sodium ion battery electrolyte can be regarded as flexible materials with certain plasticity, so that the flexible insulating member can adapt to the expansion and contraction of the volume. Moreover, by filling the sodium ion battery electrolyte between the winding core and the flexible insulating member, when the winding core expands or contracts, the surface of the entire flexible insulating member can expand and contract in time and evenly, so that the sensing result of the sensing member 140 is more accurate.

[0056] In some embodiments, the fixing member 120 includes at least two clamps 121 , and the at least two clamps 121 surround and are attached to the outer side of the battery cell 110 , and the induction member 140 is pressed tightly between the fixing member 120 and the battery cell 110 .

[0057] For example, Figure 2 As shown, the fixing member 120 includes two clamps 121 , and the cross section of each clamp 121 is U-shaped. The distance between the two clamps 121 is adjusted by the pressure member 130 , thereby changing the pressure applied to the battery cell 110 .

[0058] The fixing member 120 is provided to prevent the pressure member 130 from directly contacting the battery cell 110 and damaging the battery cell 110. In addition, the fixing member 120 is provided to uniformly transfer the pressure applied by the pressure member 130 to the battery cell 110 along the circumference of the battery cell 110.

[0059] In some embodiments, the material of the fixing member 120 is polytetrafluoroethylene, fluorinated ethylene propylene copolymer, perfluoroalkoxy resin or polyvinylidene fluoride, which has good mechanical strength (not easy to deform) and weather resistance.

[0060] In one embodiment, the cross section of the fixing member 120 is annular, with an inner diameter of 18 mm and an outer diameter of 40 mm.

[0061] In some embodiments, the pressure member 130 includes at least one clamp, which is sleeved on the outside of the fixing member 120 , and the pressure applied to the battery cell 110 can be adjusted by loosening or tightening the clamp.

[0062] For example, Figure 2 As shown, there are two clamps, which are spaced apart along the axial direction of the battery cell 110 .

[0063] The clamp is made of 304 stainless steel.

[0064] In one embodiment, the maximum diameter of the clamp is 51 mm and the minimum diameter is 27 mm.

[0065] In some embodiments, the fixing member 120 further has a first opening 123 and a second opening 124 that are arranged opposite to each other, and the first opening 123, the receiving space 122 and the second opening 124 are connected in sequence.

[0066] The shape of the fixing member 120 matches the shape of the battery cell 110. Figure 1 and Figure 2 As shown, the battery core 110 is cylindrical, and the fixing member 120 is correspondingly hollow cylindrical. In other embodiments, the battery core 110 is square columnar, and the fixing member 120 is correspondingly hollow square columnar.

[0067] In some embodiments, the sensing element 140 includes a sensing terminal 141 and a lead 142 . The sensing terminal is disposed in the receiving space 122 and attached to the surface of the flexible insulating element. The lead 142 is connected to the sensing terminal 141 and passes through the first opening 123 or the second opening 124 .

[0068] In some embodiments, the sensing element 140 is a thin film flexible pressure sensor made of polymer material, which reduces the space occupied by the sensing element 140 .

[0069] In one embodiment, the area of ​​the sensing terminal 141 is 16 mm*16 mm.

[0070] By providing the lead wire 142 , the sensing element 140 is electrically connected to an external device, so that the pressure data sensed by the sensing element 140 is transmitted to the external device.

[0071] In some embodiments, the positive electrode tab of the battery cell 110 is inserted into the first opening 123 , and the negative electrode tab of the battery cell 110 is inserted into the second opening 124 , so as to facilitate electrical connection between an external power supply device and the battery cell 110 .

[0072] like Figure 3 As shown, the present application also provides a sodium ion battery sodium precipitation detection method, which is implemented using the sodium ion battery sodium precipitation detection device 100 in any of the above embodiments, including:

[0073] Step S10, obtaining a winding core.

[0074] In some embodiments, the steel case of the cylindrical battery having a steel case may be removed to obtain a winding core.

[0075] In one embodiment, the cylindrical battery has a model number of 18650, which is a standardized lithium-ion battery size, wherein "18" represents a diameter of 18 mm and "650" represents a height of 65 mm.

[0076] Step S20 , sealing and packaging the flexible insulating member on the surface of the detection battery cell 110 to form the battery cell 110 .

[0077] In some embodiments, a 100 mm*50 mm aluminum-plastic film is cut and the roll core is sealed and packaged with the aluminum-plastic film.

[0078] In some embodiments, the positive and negative pole tabs of the winding core are lengthened (for example, to 40 mm), and then a flexible insulating member is wrapped around the surface of the winding core, and the positive and negative pole tabs of the winding core are exposed from the flexible insulating member, and then the winding core and the flexible insulating member are sealed and packaged.

[0079] In some embodiments, a through hole is opened in the sealed flexible insulating member, sodium ion battery electrolyte is injected, and then the flexible insulating member is vacuum-sealed and left to stand for 12 to 36 hours.

[0080] The standing time is not limited to the exemplified values ​​and may be 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, etc.

[0081] Step S30 , performing an aging process on the battery cell 110 .

[0082] In some embodiments, after the battery cell 110 is fully charged, it is left to stand at 40° C. to 50° C. for 0.5 to 2 days, and then the battery cell 110 is discharged to a preset power level to complete the aging process.

[0083] After the battery cell 110 is fully charged, it is allowed to stand at a temperature of 40° C., 41° C., 42° C., 43° C., 44° C., 45° C., 46° C., 47° C., 48° C., 49° C., 50° C., etc., not limited to the examples.

[0084] The standing time is not limited to the exemplified time of 0.5 day, 0.8 day, 1 day, 1.5 day, 2 days, etc.

[0085] In some embodiments, the battery cell 110 is fully charged when it is charged to 3.95V, and after standing still, the battery cell 110 is discharged to 1.5V.

[0086] In step S40 , the sensing element 140 , the fixing element 120 and the pressure element 130 are assembled on the battery cell 110 .

[0087] In some embodiments, the sensing terminal 141 of the sensing element 140 is attached to the middle of the side of the battery cell 110 , the clamp 121 is assembled on the surface of the battery cell 110 , and the sensing terminal 141 is clamped between a clamp 121 and the battery cell 110 , and then the clamp is put on the outside of the fixing element 120 .

[0088] The clamp is loosened or tightened to change the diameter of the clamp, thereby adjusting the pressure applied to the battery cell 110 .

[0089] In step S50 , a preset pressure is applied to the battery cell 110 by the pressure applying member 130 .

[0090] In some embodiments, the pressure applied to the battery cell 110 is 30 kPa to 45 kPa. Specifically, the pressure applied to the battery cell 110 is 30 kPa, 35 kPa, 40 kPa, 45 kPa, etc., which is not limited to the exemplified values.

[0091] Step S60 , charging and discharging the battery cell 110 for multiple times, and detecting the pressure change on the surface of the battery cell 110 through the sensing element 140 , thereby determining the volume change of the battery cell 110 .

[0092] In one embodiment, the battery cell 110 is connected to the battery cell 110 of an external power supply device, and multiple cycle charge and discharge tests are performed on the battery cell 110 .

[0093] The sensing element 140 is electrically connected to an external device via the lead wire 142 , so that the pressure data sensed by the sensing element 140 is transmitted to the external device, and the pressure change of the battery cell 110 is analyzed to determine whether the battery cell 110 has sodium precipitation.

[0094] Example 1

[0095] Step S1, selecting a cylindrical 18650 sodium ion battery as an experimental object, wherein the positive electrode is sodium nickel iron manganese oxide, the negative electrode is hard carbon, the rated capacity is 1.5 Ah, and the ratio of negative electrode capacity to positive electrode capacity (Negative / positive, N / P ratio) is 0.9;

[0096] Step S2, the length of the aluminum-plastic film is 690 mm, the width is 80 mm, and the lengths of the positive and negative electrode tabs of the winding core are respectively extended to 40 mm;

[0097] Step S3, placing the roll core in the middle of the aluminum-plastic film, folding it in half along the short sides, and exposing the positive electrode tab and the negative electrode tab from the short sides respectively;

[0098] Step S4, using a side sealing machine to seal the two short sides first, and then seal the long sides, leaving a 1 cm long opening on the long sides for liquid injection;

[0099] Step S5, injecting 6 g of electrolyte into the small opening in step S4, and performing vacuum sealing;

[0100] Step S6, pre-charging the packaged battery and aging it at 45° C. for 3 days;

[0101] Step S7, attach a thin film flexible sensor with an area of ​​16mm*16mm to the middle of the outer side of the battery cell 110 packaged with the aluminum-plastic film, and clamp the battery cell 110 with two U-shaped clamps 121 with a length of 650mm, an inner diameter of 18mm, and an outer diameter of 40mm, and then fix the above clamps 121 with a 304 stainless steel clamp with a maximum diameter of 51mm and a minimum diameter of 27mm;

[0102] Step S8, adjusting the pre-pressure applied by the clamp 121 to 50 kPa by adjusting the tightness of the stainless steel clamp;

[0103] Step S9, using the Blue Power Battery Test System to cycle charge and discharge the battery for 30 cycles, the charging system is: 1C charging to 3.95V, 3.95V constant voltage charging with a cut-off current of 15mA, standing for 5min, and then 1C discharging to 1.5V;

[0104] Step S10, recording the pressure changes of the battery during the charging and discharging process by a pressure collector.

[0105] Example 2

[0106] Step S1, selecting a cylindrical 18650 sodium ion battery dry electrode group as an experimental object, wherein the positive electrode is sodium nickel iron manganese oxide, the negative electrode is hard carbon, the rated capacity is 1.5 Ah, and the ratio of negative electrode capacity to positive electrode capacity (Negative / positive, N / P ratio) is 1.09;

[0107] Step S2, the length of the aluminum-plastic film is 690 mm, the width is 80 mm, and the lengths of the positive and negative electrode tabs of the winding core are respectively extended to 40 mm;

[0108] Step S3, placing the roll core in the middle of the aluminum-plastic film, folding it in half along the short sides, and exposing the positive electrode tab and the negative electrode tab from the short sides respectively;

[0109] Step S4, using a side sealing machine to seal the two short sides first, and then seal the long sides, leaving a 1 cm long opening on the long sides for liquid injection;

[0110] Step S5, injecting 6 g of electrolyte into the small opening in step S4, and performing vacuum sealing;

[0111] Step S6, pre-charging the packaged battery and aging it at 45° C. for 3 days;

[0112] Step S7, attach a thin film flexible sensor with an area of ​​16mm*16mm to the middle of the outer side of the battery cell 110 packaged with the aluminum-plastic film, and clamp the battery cell 110 with two U-shaped clamps 121 with a length of 650mm, an inner diameter of 18mm, and an outer diameter of 40mm, and then fix the above clamps 121 with a 304 stainless steel clamp with a maximum diameter of 51mm and a minimum diameter of 27mm;

[0113] Step S8, adjusting the pre-pressure applied by the clamp 121 to 50 kPa by adjusting the tightness of the stainless steel clamp;

[0114] Step S9, using the Blue Power Battery Test System to cycle charge and discharge the battery for 30 cycles, the charging system is: 1C charging to 3.95V, 3.95V constant voltage charging with a cut-off current of 15mA, standing for 5min, and then 1C discharging to 1.5V;

[0115] Step S10, recording the pressure changes of the battery during the charging and discharging process by a pressure collector.

[0116] Please refer to Figure 4 and Figure 5 By comparing Example 1 and Example 2, it can be found that the N / P ratio of Example 1 is 0.9. Since the negative electrode does not have enough sodium insertion sites, it is easy to precipitate metallic sodium on the surface of the negative electrode. Figure 6 It can be seen that the battery undergoes an irreversible pressure expansion of 5kPa per cycle on average during the charge and discharge process, and sodium precipitation can also be seen when the battery is disassembled after the cycle.

[0117] The N / P ratio of Example 2 is 1.09, and no irreversible pressure expansion occurs during the cycle. Figure 6 As shown, no obvious sodium precipitation was observed after the battery was disassembled.

[0118] Therefore, combined with Figures 4 to 7 It can be seen from the verification results that the sodium ion battery sodium precipitation detection device 100 and the detection method of the present application can detect the pressure change of the battery cell 110 during the charging and discharging process, and can be used to determine whether the sodium precipitation phenomenon occurs.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0120] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A sodium ion battery sodium precipitation detection device, characterized in that: include: A flexible insulating member is sealed and coated on the surface of the winding core to define a battery core; A fixing member having a receiving space, wherein the battery cell is arranged in the receiving space; A pressure-applying member, used to apply a preset pressure to the battery cell; The sensing element is in contact with the outer surface of the battery cell and is used to sense the pressure change on the surface of the battery cell, thereby determining the volume change of the battery cell.

2. The sodium ion battery sodium analysis detection device according to claim 1, characterized in that: The flexible insulating member is made of aluminum-plastic film, multi-layer co-extruded composite film or aluminum-plated film composite material; The positive electrode tab and the negative electrode tab of the winding core are respectively exposed from the flexible insulating member; Sodium ion battery electrolyte is also filled between the flexible insulating member and the winding core.

3. The sodium ion battery sodium precipitation detection device according to claim 1, characterized in that, The fixing member includes at least two clamps, the at least two clamps are enclosed and attached to the outer side of the battery core, and the induction member is pressed tightly between the fixing member and the battery core; The pressure-applying member includes at least one clamp, which is sleeved on the outside of the fixing member. The pressure applied to the battery cell can be adjusted by loosening or tightening the clamp.

4. The sodium ion battery sodium analysis detection device according to claim 2, characterized in that, The fixing member further comprises a first opening and a second opening which are arranged opposite to each other, and the first opening, the receiving space and the second opening are connected in sequence.

5. The sodium ion battery sodium precipitation detection device according to claim 4, characterized in that, The sensing component includes a sensing terminal and a lead, wherein the sensing terminal is arranged in the receiving space and attached to the surface of the battery cell, the lead is connected to the sensing terminal and is passed through the first opening or the second opening, the positive electrode tab of the battery cell is passed through the first opening, and the negative electrode tab of the battery cell is passed through the second opening.

6. A sodium ion battery sodium precipitation detection method implemented by the sodium ion battery sodium precipitation detection device according to any one of claims 1 to 5, characterized in that: include: Get the roll core; The flexible insulating member is sealed and packaged on the surface of the detection battery cell to form a battery cell; Perform aging treatment on the battery cells; Assemble the induction component, the fixing component and the pressure component on the battery cell; Applying a preset pressure to the battery cell by means of a pressure applying member; The battery cell is charged and discharged multiple times, and the pressure change on the surface of the battery cell is detected by the sensor to determine the volume change of the battery cell.

7. The sodium ion battery sodium analysis detection method according to claim 6, characterized in that: The positive and negative pole ears of the winding core are lengthened, and then the flexible insulating member is wrapped on the surface of the winding core, and the positive and negative pole ears of the winding core are exposed from the flexible insulating member, and then the winding core and the flexible insulating member are sealed and packaged.

8. The sodium ion battery sodium analysis detection method according to claim 7, characterized in that: A through hole is opened in the sealed flexible insulating member, and the sodium ion battery electrolyte is injected. The flexible insulating member is then vacuum-sealed and left to stand for 12 to 36 hours.

9. The sodium ion battery sodium analysis detection method according to claim 6, characterized in that: After fully charging the battery cell, place it at 40℃ to 50℃ for 0.5 to 2 days, then discharge the battery cell to the preset power to complete the aging process.

10. The sodium ion battery sodium precipitation detection method according to claim 6, characterized in that: The pressure applied by the pressure-applying member to the battery cell is 30 kPa to 45 kPa.

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