Water-based sodium ion battery

Abstract

The invention provides a water-based sodium ion battery. According to the water-based sodium ion battery, the positive tabs are arranged on the two sides of the positive pole piece, the negative tabs are arranged on the two sides of the negative pole piece, the tabs are arranged at the two ends of the positive pole piece and the two ends of the negative pole piece, two adjacent battery cell groups are connected in series through the tabs, the current transmission distance can be reduced, the internal resistance of the battery is effectively reduced, and therefore the current transmission efficiency is improved; the uniform distribution of current can be realized, and the risk of local overheating is reduced; the tabs are arranged at the two ends of the positive pole piece and the negative pole piece, so that the size of the battery cell can be enlarged on the premise that the power performance is not sacrificed, the battery cell has remarkable significance in improving the energy density and the endurance mileage of the battery, the battery cell is allowed to be matched with a battery management system for use, finer charge and discharge control is realized, and the service life of the battery cell is prolonged. Therefore, the service life and the overall performance of the battery are optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium ion batteries, and in particular to a water-based sodium ion battery. Background Art

[0002] New secondary battery systems such as sodium-ion batteries have received widespread attention in recent years. Their battery systems can be used in the fields of electric vehicles and battery energy storage systems. Sodium-ion batteries have abundant sodium resources, obvious raw material cost advantages, and a high degree of industrialization. The costs of the positive and negative electrode materials and sodium salt electrolytes used are lower than those of lithium batteries. Among them, water-based sodium-ion batteries will be the preferred technology for new electrochemical energy storage in the future because their raw materials are mainly aqueous electrolytes, they have low manufacturing costs, and they are safer and more environmentally friendly. However, due to the low power density of water-based batteries, a large number of batteries need to be installed in series and in parallel, which increases the volume and weight. The electrochemical performance in terms of energy density and rate performance is poor, which restricts them in practical applications. Based on the defects of current water-based sodium-ion batteries, it is necessary to improve them. Summary of the invention

[0003] In view of this, the present invention proposes a water-based sodium ion battery to solve the defects of the prior art.

[0004] The present invention provides a water-based sodium ion battery, comprising:

[0005] case;

[0006] At least two battery cell groups, each of which is located in the housing, each of which includes a plurality of electric chips, each of which includes:

[0007] A positive electrode plate, wherein positive electrode tabs are provided on both sides of the positive electrode plate;

[0008] Water system diaphragm;

[0009] A negative electrode plate, wherein negative electrode tabs are provided on both sides of the negative electrode plate;

[0010] Among them, the positive electrode tabs of the corresponding positive electrode sheets in any two adjacent battery cell groups are connected to the negative electrode tabs corresponding to the negative electrode sheets.

[0011] Preferably, the housing comprises:

[0012] A housing, wherein the battery cell group is located inside the housing;

[0013] A cover plate is disposed on the shell.

[0014] Preferably, at least one partition is provided in the shell, and the partition divides the interior of the shell into at least two accommodating chambers, and the accommodating chambers correspond to the battery cell groups one by one, and the battery cell groups are located in the accommodating chambers.

[0015] Preferably, the positive electrode tab comprises a first horizontal portion and a first bent portion, the first bent portion is inclined, one end of the first bent portion is connected to the positive electrode sheet, and the other end is connected to the first horizontal portion;

[0016] The negative electrode ear comprises a second horizontal portion and a second bent portion, the second bent portion is inclined, one end of the second bent portion is connected to the negative electrode sheet, and the other end is connected to the second horizontal portion;

[0017] The first horizontal portion of the corresponding positive electrode tab in any two adjacent battery cell groups is connected to the second horizontal portion of the negative electrode tab.

[0018] Preferably, an electrolyte injection hole is provided on the cover plate corresponding to the battery cell group.

[0019] Preferably, a plurality of battery cell fixing clips are provided in the accommodating chamber for fixing the battery cell group.

[0020] Preferably, the cover plate is also provided with an exhaust valve;

[0021] A groove is provided on the cover plate corresponding to the battery core fixing clip, and the upper end of the battery core fixing clip extends into the groove.

[0022] Preferably, current collecting terminals are provided at both ends of the cover plate, and a protective shell is rotatably provided on the current collecting terminal;

[0023] The current collecting terminal is provided with a current collecting hole.

[0024] Preferably, the positive electrode plate comprises a positive electrode current collector and a positive electrode coating located on the surface of the positive electrode current collector;

[0025] The positive electrode coating comprises a positive electrode active material, wherein the positive electrode active material comprises at least one of a metal oxide sodium salt, a metal cyanide sodium salt, and a metal phosphate sodium salt;

[0026] The negative electrode plate comprises a negative electrode current collector and a negative electrode coating located on the surface of the negative electrode current collector;

[0027] The negative electrode coating includes a negative electrode active material, and the negative electrode active material includes a metal sodium phosphate salt.

[0028] Preferably, the water system membrane includes any one of a PP membrane, a PE membrane, a cellulose membrane, a nylon membrane, a glass fiber membrane, a non-woven fabric membrane, and a ceramic membrane.

[0029] The water-based sodium ion battery of the present invention has the following beneficial effects compared with the prior art:

[0030] 1. In the water-based sodium ion battery of the present invention, positive pole ears are arranged on both sides of the positive pole sheet, and negative pole ears are arranged on both sides of the negative pole sheet. The positive pole ears of the corresponding positive pole sheets in any two adjacent battery cell groups are connected to the negative pole ears corresponding to the negative pole sheets, so as to realize the series connection of adjacent battery cell groups; the pole ears are the positive and negative electrode lead-out terminals of the battery cells, and are the only way for current transmission; compared with directly connecting two single batteries in series, the present invention provides pole ears at both ends of the positive pole sheet and the negative pole sheet, and realizes the series connection of two adjacent battery cell groups through the pole ears, which can reduce the distance of current transmission, effectively reduce the internal resistance of the battery, and thus The invention improves the transmission efficiency of the current; helps to achieve uniform distribution of the current and reduce the risk of local overheating, which is crucial to improving the performance of the battery under high-load working conditions; supports the design of battery cells with larger capacity and size: the invention provides tabs at both ends of the positive electrode sheet and the negative electrode sheet, so that the size of the battery cell can be enlarged without sacrificing the power performance, which is of great significance for improving the energy density and driving range of the battery, and allows the battery cell to be used in conjunction with the battery management system (BMS) to achieve more precise charge and discharge control, thereby optimizing the service life and overall performance of the battery;

[0031] 2. The water-based sodium ion battery of the present invention has the characteristics of small volume and small footprint. Combined with the high safety of water-based sodium ion batteries with water as the main electrolyte, it provides potential for miniaturization design; it can design battery cells with smaller volume and more suitable for integration into compact devices, meet the needs of small energy storage systems and special power applications, and can comprehensively improve the volume energy density or weight energy density of the battery;

[0032] 3. The main body of the water-based sodium ion battery of the present invention includes two battery cell groups, which are connected in series through the tabs. The voltage of the bare battery cell is 1 to 1.5V, and the voltage of one battery body is 2 to 3V. Focusing on the innovation of the 3V voltage design of the battery cell, the design accurately connects with the current application standards of lithium batteries, thus showing multiple significant advantages. Through compatibility and standardization, the battery cell is connected with a variety of portable devices and systems on the market, which improves the versatility of the battery and the production efficiency of the manufacturer. At the same time, the 3V design optimizes energy efficiency, reduces voltage conversion losses, and enhances the performance of the overall system. The 3V voltage design of the battery cell, with its many advantages, shows strong market competitiveness and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 It is a schematic structural diagram of the water-based sodium ion battery of the present invention;

[0035] Figure 2 A schematic diagram of the structure of a battery cell group in one embodiment of the present invention;

[0036] Figure 3 It is a schematic structural diagram of a battery cell group in another embodiment of the present invention;

[0037] Figure 4 This is a schematic structural diagram of a water-based sodium ion battery in another embodiment of the present invention;

[0038] Figure 5 is a top view of the cover plate of the present invention;

[0039] Figure 6 A bottom view of the cover plate of the present invention;

[0040] Figure 7 It is a schematic structural diagram of the current collecting terminal of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The present application embodiment provides a water-based sodium ion battery, such as Figures 1 to 5 As shown, including:

[0043] Shell 1;

[0044] At least two battery cell groups 2 are located in the housing 1. Each battery cell group 2 includes a plurality of electric chips, and each electric chip includes:

[0045] A positive electrode plate 21, with positive electrode tabs 22 on both sides of the positive electrode plate;

[0046] Water system membrane 23;

[0047] A negative electrode plate 24, with negative electrode tabs 25 on both sides of the negative electrode plate 24;

[0048] The positive electrode tabs 22 of the corresponding positive electrode sheets 21 in any two adjacent battery cell groups 2 are connected to the negative electrode tabs 25 corresponding to the negative electrode sheets 24 .

[0049] The water-based sodium ion battery of the present invention comprises a shell 1, wherein at least two battery cell groups 2 are arranged in the shell 1, and the specific number of battery cell groups 2 can be 2, 3, 4, 5...n, each battery cell group 2 comprises a plurality of electric chips, each electric chip comprises: a positive electrode sheet 21, a water-based diaphragm 23, and a negative electrode sheet 24, positive electrode tabs 22 are arranged on both sides of the positive electrode sheet, and negative electrode tabs 25 are arranged on both sides of the negative electrode sheet 24, and the positive electrode tabs 22 of the corresponding positive electrode sheets 21 in any two adjacent battery cell groups 2 are connected to the negative electrode tabs 25 corresponding to the negative electrode sheets 24, so as to realize the series connection of two adjacent battery cell groups; the tabs serve as the positive and negative electrode lead-out terminals of the battery cell and are the only way for current transmission; compared with directly connecting two single batteries in series, the present invention connects the positive electrode sheet 21 to the negative electrode sheet 24 by connecting the positive electrode tabs 22 and the negative electrode tabs 25 of the negative electrode sheet 24. Ears are provided at both ends of the positive pole piece and the negative pole piece. The ear is used to connect two adjacent battery cell groups in series, which can reduce the distance of current transmission and effectively reduce the internal resistance of the battery, thereby improving the current transmission efficiency; it is helpful to achieve uniform distribution of current and reduce the risk of local overheating, which is crucial for improving the performance of the battery under high-load working conditions; it supports the design of battery cells with larger capacity and size: the present invention provides ear ears at both ends of the positive pole piece and the negative pole piece, so that the battery cell can be enlarged in size without sacrificing power performance, which is of significant significance for improving the energy density and cruising range of the battery, and allows the battery cell to be used in conjunction with the battery management system (BMS) to achieve more precise charge and discharge control, thereby optimizing the battery life and overall performance.

[0050] In some embodiments, the housing 1 comprises:

[0051] A housing 11, wherein the battery cell group 2 is located in the housing 11;

[0052] The cover plate 12 is disposed on the outer shell 11 .

[0053] In some embodiments, at least one partition 13 is disposed in the housing 11 , and the partition 13 divides the interior of the housing 11 into at least two accommodating chambers 14 . The accommodating chambers 14 correspond to the battery cell groups 2 one by one, and the battery cell groups 2 are located in the accommodating chambers 14 .

[0054] In some embodiments, the positive electrode tab 22 includes a first horizontal portion 221 and a first bent portion 222, the first bent portion 222 is tilted, one end of the first bent portion 222 is connected to the positive electrode sheet 21, and the other end is connected to the first horizontal portion 221;

[0055] The negative electrode ear includes a second horizontal portion and a second bent portion, the second bent portion is inclined, one end of the second bent portion is connected to the negative electrode sheet 24, and the other end is connected to the second horizontal portion;

[0056] The first horizontal portion of the corresponding positive electrode tab in any two adjacent battery cell groups is connected to the second horizontal portion of the negative electrode tab.

[0057] In the above embodiment, the positive electrode ear 22 includes a first horizontal portion 221 and a first bent portion 222, and the first bent portion 222 is tilted, that is, the positive electrode ear 22 and the positive electrode sheet 21 are arranged in a "Z" shape; similarly, the negative electrode ear includes a second horizontal portion and a second bent portion, and the second bent portion is tilted, that is, the negative electrode ear and the negative electrode sheet are arranged in a "Z" shape; the first horizontal portion of the positive electrode ear is connected to the second horizontal portion of the negative electrode ear, so that the first horizontal portion, the first bent portion of the positive electrode ear, the second horizontal portion, and the second bent portion of the negative electrode ear are enclosed to form a chamber, and the partition 13 is located in the chamber, that is, the structural design of the positive electrode ear and the negative electrode ear facilitates the positive electrode ear to bypass the partition 13 and then connect to the negative electrode ear; the positive electrode sheet, the negative electrode sheet and the water-based diaphragm can be stacked in a "Z" shape or other stacks; the electric chip is encapsulated in the accommodating chamber, and the electrolyte is infiltrated in the electric chip. The number of electric chips contained in a battery cell may be one or more, and those skilled in the art may select one according to specific practical needs. For example, a battery cell group 2 includes 2 to 999 pairs of electric chips, which are connected in parallel or in series.

[0058] In some embodiments, the shape of the housing 11 is not particularly limited, and it can be cylindrical, rectangular, or any other shape; in some embodiments, the number of chambers 14 in the housing 11 can be arranged in 1-99×2-99 (rows×columns); the housing 11 can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The material of accessories such as the battery cover and the housing can be plastic, and as plastic, polypropylene, polybutylene terephthalate, and polybutylene succinate can be listed; the welding method of the tab can be ultrasonic welding, laser welding, etc.

[0059] In some embodiments, an electrolyte injection hole 15 is provided on the cover plate 12 at a position corresponding to the battery cell group. During the production process, each battery cell group can be independently injected with electrolyte to ensure the stability of the battery.

[0060] In some embodiments, a plurality of battery cell fixing clips 16 are disposed in the accommodating chamber 14 for fixing the battery cell group.

[0061] In some embodiments, the cover plate 12 is further provided with an exhaust valve 17; specifically, the exhaust valve 17 is a pressure-limiting air release valve safety device, which can automatically exhaust gas by limiting the pressure after reaching a certain pressure during battery gas evolution.

[0062] In some embodiments, a groove 18 is provided on the cover plate 12 corresponding to the battery cell fixing clip, and the upper end of the battery cell fixing clip 16 extends into the groove 18. When the cover plate 12 is closed on the outer shell 11, the upper end of the battery cell fixing clip 16 is inserted into the groove 18, so that the battery cell fixing clip 16 plays the role of fixing the battery cell group.

[0063] In some embodiments, current collecting terminals 3 are further provided at both ends of the cover plate 12, and a protective shell 31 is rotatably provided on the current collecting terminals;

[0064] The current collecting terminal 3 is provided with a current collecting hole 32 .

[0065] The current collecting terminal is used to connect the upper and lower battery monomer groups in series. The current collecting port at one end can be designed to be single, double, or designed to be adapted to a storage photovoltaic cable plug. The external tabs of the bare battery cell group are connected to the inner side of the current collecting terminal, and the metal on the outer side of the current collecting terminal is inserted into the external power terminal. The protective shell 3 can be flipped up and down to provide protection against rain, sun, etc.

[0066] In some embodiments, the cover plate 12 is further provided with a fixing hole 19, wherein the fixing hole 19 and the hexagonal screws, cross screws, etc. are used to realize the upper and lower splicing of the battery cells, thereby connecting them into a battery module form or a battery pack form, etc.

[0067] In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode coating located on the surface of the positive electrode current collector;

[0068] The positive electrode coating includes a positive electrode active material, and the positive electrode active material includes at least one of a metal oxide sodium salt, a metal cyanide sodium salt, and a metal phosphate sodium salt.

[0069] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode coating located on the surface of the negative electrode current collector;

[0070] The negative electrode coating includes a negative electrode active material, and the negative electrode active material includes a metal sodium phosphate salt.

[0071] Specifically, the chemical formula of metal cyanide sodium salt is: x M[Fe(CN)6] y ·zH2O, A is usually an alkali metal ion such as Na, K, Ca, M is a transition metal ion, and x, y, z are their stoichiometric numbers.

[0072] The general formula of metal oxide sodium salt is Na x M(MO4), wherein M is usually a transition metal such as Co, Mn, Ni, Zn, Cu, Fe, etc., and M can be a multi-element transition metal element.

[0073] Metallic sodium phosphate general formula: Na x M y(XO4) z , where M is Zr, Ti, etc., X is Si, P, etc., and x, y, z are stoichiometric numbers.

[0074] In some embodiments, the water system membrane includes any one of a PP membrane, a PE membrane, a cellulose membrane, a nylon membrane, a glass fiber membrane, a non-woven membrane, and a ceramic membrane.

[0075] In some embodiments, the positive electrode coating and the negative electrode coating further include carbon materials, such as hard carbon, soft carbon, graphene, etc.

[0076] In some embodiments, the positive electrode current collector and the negative electrode current collector matrix materials include: aluminum mesh, nickel mesh, titanium mesh, copper mesh, carbon cloth, graphite cloth, aluminum foil, nickel foil, titanium foil, copper foil, foamed aluminum, foamed nickel, foamed titanium, foamed copper, etc.

[0077] In some embodiments, the electrolyte used in the water-based sodium ion battery of the present invention includes water and sodium salts, and the sodium salts include sodium perchlorate, sodium nitrate, sodium sulfate, sodium acetate, ammonium acetate, etc. and other sodium salts with good sodium element insertion and extraction capabilities.

[0078] In some embodiments, the battery body of the present invention includes two battery cell groups, which are connected in series through pole ears. The voltage of the bare battery cell is 1 to 1.5V, and the voltage of one battery body is 2 to 3V. Focusing on the innovation of the 3V voltage design of the battery cell, the design accurately connects with the current application standards of lithium batteries, thus showing multiple significant advantages. Through compatibility and standardization, the battery cell is connected with a variety of portable devices and systems on the market, which improves the versatility of the battery and the production efficiency of the manufacturer. At the same time, the 3V design optimizes energy efficiency, reduces voltage conversion losses, and enhances the performance of the overall system. The 3V voltage design of the battery cell, with its many advantages, shows strong market competitiveness and broad application prospects.

[0079] The water-based sodium ion battery of the present application is further described below with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0080] Examples 1 to 9

[0081] The present embodiments 1 to 9 provide a water-based sodium ion battery structure such as Figure 1 As shown, the positive electrode material (i.e., positive electrode active material), the negative electrode material (negative electrode active material), the main sodium salt in the electrolyte and the solvent used for the positive electrode plate and the negative electrode plate are shown in Table 1 below, and the performance of the test battery is shown in Table 1.

[0082] Comparative Examples 1 to 3

[0083] The water-based sodium ion batteries provided in Comparative Examples 1 to 3 are the same as those in Example 1, except that the electrolyte in Comparative Example 1 is sodium oxalate, the electrolyte in Comparative Example 2 is sodium citrate, and the electrolyte in Comparative Example 3 is sodium carbonate, as shown in Table 1.

[0084] The battery performance tests in Examples 1 to 9 and Comparative Examples 1 to 3 are as follows:

[0085] The embodiments and comparative examples were assembled into batteries for electrochemical testing. At room temperature (25±2°C) and normal pressure (0.1MPa), the sodium ion batteries prepared by the embodiments and comparative examples were charged at a constant current of 0.1C to the upper limit of the charge and discharge cut-off voltage (2V), then left to stand for 5 minutes, and then discharged at a constant current of 0.1C to the lower limit of the charge and discharge cut-off voltage (0V), and left to stand for 5 minutes. This is a cyclic charge and discharge process. The voltage platform can be recorded, and the discharge capacity this time is recorded as the 0.1C first cycle discharge capacity. After 500 cycles of charge and discharge, the discharge capacity after 500 cycles is obtained. The discharge capacity after 500 cycles of 0.1C is divided by the 0.1C first cycle discharge capacity, which is the capacity retention rate of the sodium ion battery after 500 cycles at 0.1C.

[0086] The embodiment and the comparative example are assembled into a battery for high and low temperature cycle performance test method. At low temperature (-20±2℃) and normal pressure (0.1MPa), the battery charge and discharge voltage interval is maintained at 0V-2V, and the battery is cycled at a current density of 0.1C. The 0.1C first cycle discharge capacity is first recorded, and then the discharge capacity after 200 cycles is obtained after 200 cycles of charge and discharge. The capacity retention rate after 200 cycles of low temperature cycles is recorded in the above manner. At high temperature (45±2℃) and normal pressure (0.1MPa), the battery charge and discharge voltage interval is maintained at 0V-2V, and the battery is cycled at a current density of 0.1C. The 0.1C first cycle discharge capacity is first recorded, and then the discharge capacity after 200 cycles of charge and discharge is obtained after 200 cycles of charge and discharge. The capacity retention rate after 200 cycles of low temperature cycles is recorded in the above manner.

[0087] The examples and comparative examples were assembled into batteries for battery energy density testing. At room temperature (25±2°C) and pressure (0.1MPa), the water-based sodium ion system battery was charged to 2V at a constant current of 0.2C, then charged at a constant voltage of 2V until the current was less than or equal to 0.05C, and then left to stand for 5 minutes, and the charging capacity at this time was recorded, i.e., the first charging capacity; then discharged at a constant current of 0.2C until the voltage was less than or equal to 0.5V, and the discharge capacity at this time was recorded. Energy density = discharge capacity / mass of active material. Among them, active material refers to positive electrode active material and negative electrode active material.

[0088] The performance test results of the water-based sodium ion batteries in Examples 1 to 9 of the present application and Comparative Examples 1 to 3 are shown in Table 1.

[0089] Table 1 - Performance test results of water-based sodium ion batteries in Examples 1 to 9 and Comparative Examples 1 to 3

[0090]

[0091]

[0092] The chemical formula of the Prussian blue material used in the positive electrode active materials in Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1 is Na2Mn[Fe(CN)6]·0.3H2O, and the chemical formula of the layered oxide used in the positive electrode active materials in Examples 4 to 6 is NaNi 0.7 Co 0.1 Mn 0.2 O2 / Na5FeO4 (coating), the chemical formula of the polyanion material used in the positive electrode active material in Examples 7 to 9 is Na4Fe3(PO4)2P2O7; the chemical formula of the negative electrode active material sodium titanium phosphate in Examples 1 to 9 and Comparative Examples 1 to 3 is NaTi2(PO4)3 / C (carbon coating); the conductive material of the pole piece is Super P, the binder is PVDF, and the solvent is NMP; the ratio of the positive or negative electrode active material, the conductive material and the binder is 9:1:1. The electrolyte concentration is: sodium perchlorate is 17.0 mol / L, sodium sulfate is 1.3 mol / L, sodium nitrate is 1.0 mol / L, sodium oxalate is 0.2 mol / L, sodium citrate is 0.5 mol / L, and sodium carbonate is 2.0 mol / L.

[0093] It can be seen from Table 1 that the shell used in this battery system is more suitable for the high-concentration electrolyte formula of the strong acid salt system, which can not only improve the voltage platform of the water-based battery, but also has a high battery capacity retention rate in high and low temperature environments, and can adapt to practical application scenarios in a wide temperature range.

[0094] The internal resistance test was conducted on the bare cell group of the water-based sodium ion battery in Example 1, which has a centrally symmetrical output tab monomer connected in series at both ends; the positive and negative electrode materials, electrolyte, and separator used in Comparative Example 4 are the same as those in Example 1, except that a single bare cell group of two battery cells in Comparative Example 4 is provided, which has a single end of a symmetrical output tab monomer connected in series. The internal resistance test method uses the AC method (1KHz), and the battery is 40% SOC.

[0095] Table 2 - Test results of internal resistance performance of water-based sodium ion batteries

[0096]

[0097]

[0098] As can be seen from Table 2, the water-based sodium ion battery structure design of the present invention has only half the internal resistance of a single bare cell group of two battery cells in the currently common soft-pack or square shell lamination process with single-end symmetrical tab cells connected in series, proving that the water-based sodium ion battery of the present invention has good current carrying capacity.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A water-based sodium ion battery, characterized in that: include: case; At least two battery cell groups, each of which is located in the housing, each of which includes a plurality of electric chips, each of which includes: A positive electrode plate, wherein positive electrode tabs are provided on both sides of the positive electrode plate; Water system diaphragm; A negative electrode plate, wherein negative electrode tabs are provided on both sides of the negative electrode plate; Among them, the positive electrode tabs of the corresponding positive electrode sheets in any two adjacent battery cell groups are connected to the negative electrode tabs corresponding to the negative electrode sheets.

2. The water-based sodium ion battery according to claim 1, characterized in that: The housing comprises: A housing, wherein the battery cell group is located inside the housing; A cover plate is disposed on the shell.

3. The water-based sodium ion battery according to claim 2, characterized in that: At least one partition is arranged in the shell, and the partition divides the inside of the shell into at least two accommodating chambers. The accommodating chambers correspond to the battery cell groups one by one, and the battery cell groups are located in the accommodating chambers.

4. The water-based sodium ion battery according to claim 3, characterized in that: The positive electrode tab comprises a first horizontal portion and a first bent portion, the first bent portion is arranged obliquely, one end of the first bent portion is connected to the positive electrode sheet, and the other end is connected to the first horizontal portion; The negative electrode ear comprises a second horizontal portion and a second bent portion, the second bent portion is inclined, one end of the second bent portion is connected to the negative electrode sheet, and the other end is connected to the second horizontal portion; The first horizontal portion of the corresponding positive electrode tab in any two adjacent battery cell groups is connected to the second horizontal portion of the negative electrode tab.

5. The water-based sodium ion battery according to claim 2, characterized in that: The cover plate is provided with an electrolyte injection hole at a position corresponding to the battery cell group.

6. The water-based sodium ion battery according to claim 2, characterized in that: A plurality of battery cell fixing clips are arranged in the accommodating chamber for fixing the battery cell group.

7. The water-based sodium ion battery according to claim 2, characterized in that: The cover plate is also provided with an exhaust valve; A groove is provided on the cover plate corresponding to the battery core fixing clip, and the upper end of the battery core fixing clip extends into the groove.

8. The water-based sodium ion battery according to claim 2, characterized in that: The two ends of the cover plate are also provided with current collecting terminals, and a protective shell is rotatably provided on the current collecting terminals; The current collecting terminal is provided with a current collecting hole.

9. The water-based sodium ion battery according to claim 1, characterized in that: The positive electrode plate includes a positive electrode current collector and a positive electrode coating located on the surface of the positive electrode current collector; The positive electrode coating comprises a positive electrode active material, wherein the positive electrode active material comprises at least one of a metal oxide sodium salt, a metal cyanide sodium salt, and a metal phosphate sodium salt; The negative electrode plate comprises a negative electrode current collector and a negative electrode coating located on the surface of the negative electrode current collector; The negative electrode coating includes a negative electrode active material, and the negative electrode active material includes a metal sodium phosphate salt.

10. The water-based sodium ion battery according to claim 1, characterized in that: The water system diaphragm includes any one of a PP diaphragm, a PE diaphragm, a cellulose diaphragm, a nylon diaphragm, a glass fiber diaphragm, a non-woven fabric diaphragm, and a ceramic diaphragm.

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