Lithium battery with uniform temperature characteristic and preparation method thereof

Abstract

The lithium battery comprises a battery shell, a battery cell and an electrolyte, the battery cell comprises a uniform-temperature positive plate, a uniform-temperature negative plate and a diaphragm, the uniform-temperature positive plate comprises a positive top plate and a positive bottom plate, a plurality of first columnar supports are fixedly arranged on the inner side of the positive top plate, and a plurality of second columnar supports are fixedly arranged on the inner side of the positive bottom plate. An aluminum wire mesh is clamped between the first columnar support and the positive electrode bottom plate, a first transverse groove is formed in the inner side of the positive electrode bottom plate, and acetone is injected into a cavity between the positive electrode top plate and the positive electrode bottom plate; the uniform-temperature negative plate comprises a negative top plate and a negative bottom plate, a plurality of second columnar supports are fixedly arranged on the inner side of the negative top plate, a copper wire net is arranged between the second columnar supports and the negative bottom plate, a second transverse groove is formed in the inner side of the negative bottom plate, and ultrapure water is injected into a cavity between the negative top plate and the negative bottom plate. The problem of non-uniform temperature of the lithium battery in the overcharge and charge-discharge processes can be solved, so that the service life of the lithium battery is further prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and in particular to a lithium battery with a temperature-averaging characteristic and a preparation method thereof. Background Art

[0002] Lithium batteries are batteries that use lithium alloy metal oxides as positive electrode materials, graphite as negative electrode materials, and electrolytes as media. They store and release energy through the movement of lithium ions between the positive and negative electrodes. Due to the advantages of high energy density, long cycle life, and no memory effect, lithium batteries are widely used in consumer products such as mobile phones, laptops, and digital products. However, overheating of the electrodes at the tabs during overcharging of lithium batteries, and excessively high temperatures of the electrodes near the tabs during normal charging and discharging, will cause uneven temperature distribution in the battery, reducing the cycle life of lithium batteries and increasing the aging rate.

[0003] The battery shell of a lithium battery is usually made of materials with low thermal conductivity, such as aluminum, steel, iron, and aluminum-plastic film. At the same time, an electrolyte with extremely low thermal conductivity composed of an organic solvent is filled between the battery shell and the battery cell. In order to meet the need for temperature balance during supercharging and operation of lithium batteries, air cooling or liquid cooling plates are often used outside the battery shell. The heat dissipation method outside the lithium battery shell is often unable to effectively evenly heat and dissipate the battery cells. Therefore, it is very necessary to develop a lithium battery with temperature-averaging characteristics to solve the problem of overheating and shortened life of lithium batteries due to uneven battery cell temperature during supercharging and operation without changing the existing lithium battery preparation process. Summary of the invention

[0004] The first technical problem to be solved by the present application is to provide a lithium battery with a uniform temperature characteristic to solve the problem of uneven temperature of the lithium battery during overcharging and charging and discharging, thereby further improving the life of the lithium battery.

[0005] The second technical problem to be solved by the present application is to provide a method for preparing a lithium battery with a uniform temperature characteristic.

[0006] To solve the first technical problem mentioned above, the technical solution of this application is:

[0007] A lithium battery with a uniform temperature characteristic, comprising a battery shell, a battery cell and an electrolyte, wherein the battery cell is fixedly arranged inside the battery shell, the inner cavity of the battery shell is filled with electrolyte, the battery cell comprises a uniform temperature positive plate, a uniform temperature negative plate and a diaphragm, the diaphragm is arranged between the uniform temperature positive plate and the uniform temperature negative plate, the uniform temperature positive plate is provided with a positive ear, the uniform temperature negative plate is provided with a negative ear, the uniform temperature positive plate comprises a positive top plate and a positive bottom plate, a plurality of first columnar supports are fixedly arranged inside the positive top plate, a plurality of first columnar supports are sandwiched between the first columnar supports and the positive bottom plate Aluminum wire mesh, a first transverse groove is arranged on the inner side of the positive bottom plate, the aluminum wire mesh and the first transverse groove constitute a positive electrode liquid wick structure, and the chamber between the positive top plate and the positive bottom plate is filled with acetone; the temperature-averaging negative plate comprises a negative top plate and a negative bottom plate, a plurality of second columnar supports are fixedly arranged on the inner side of the negative top plate, a copper wire mesh is arranged between the second columnar support and the negative bottom plate, a second transverse groove is arranged on the inner side of the negative bottom plate, the copper wire mesh and the second transverse groove constitute a negative electrode liquid wick structure, and the chamber between the negative top plate and the negative bottom plate is filled with ultrapure water.

[0008] Preferably, interconnecting grooves are provided at both ends of the first transverse groove and both ends of the second transverse groove.

[0009] Preferably, the temperature-averaging positive plate is made of metal aluminum, the temperature-averaging negative plate is made of metal copper, and the battery shell is made of steel shell, aluminum shell, nickel-plated iron shell or aluminum-plastic shell.

[0010] Preferably, the interiors of the temperature-uniform positive electrode plate and the temperature-uniform negative electrode plate are both in a vacuum or negative pressure state, and the interior of the battery housing is in a vacuum state.

[0011] Preferably, the temperature-averaging positive plate and the temperature-averaging negative plate are cylindrical, the temperature-averaging negative plate is sleeved inside the temperature-averaging positive plate, and the diaphragm is provided between the temperature-averaging positive plate and the temperature-averaging negative plate and inside the temperature-averaging negative plate.

[0012] Preferably, both sides of the temperature-averaging positive electrode plate are coated with a positive electrode material mixed with a lithium compound material, a binder and a conductive agent, and both sides of the temperature-averaging negative electrode plate are coated with a negative electrode material mixed with graphite, a binder and a conductive agent.

[0013] To solve the above second technical problem, the technical solution of this application is:

[0014] A method for preparing a lithium battery with a uniform temperature characteristic, characterized by comprising the following steps:

[0015] (1) Preparation of electrode plates: etching a first columnar support on the inner surface of the positive electrode top plate, etching a first transverse groove with equal spacing on the inner surface of the positive electrode bottom plate, laying an aluminum wire mesh between the positive electrode top plate and the positive electrode bottom plate, welding the positive electrode top plate and the positive electrode bottom plate around by vacuum diffusion welding, and then injecting acetone to obtain a uniform temperature positive electrode plate; etching a second columnar support on the inner surface of the negative electrode top plate, etching a second transverse groove with equal spacing on the inner surface of the negative electrode bottom plate, laying a copper wire mesh between the negative electrode top plate and the negative electrode bottom plate, welding the negative electrode top plate and the negative electrode bottom plate around by vacuum diffusion welding, and then injecting ultrapure water to obtain a uniform temperature negative electrode plate;

[0016] (2) Plate coating: coating the positive electrode material on both sides of the uniform temperature positive electrode plate, and then rolling and baking the plate; coating the negative electrode material on both sides of the uniform temperature negative electrode plate, and then rolling and baking the plate; welding the positive electrode lug to the uniform temperature positive electrode plate, and welding the negative electrode lug to the uniform temperature negative electrode plate;

[0017] (3) Preparation of battery cells: a separator is arranged between the temperature-averaging positive electrode plate and the temperature-averaging negative electrode plate obtained in step (2) to fix the obtained battery cells, and the packaged battery cells are loaded into a battery housing;

[0018] (4) Primary injection: injecting electrolyte into the battery housing, then sealing it with a rubber plug, subjecting it to high temperature aging treatment so that the electrolyte infiltrates the temperature-averaged positive plate, the temperature-averaged negative plate and the separator, pulling out the rubber plug, and charging the lithium battery in a constant temperature and humidity environment to activate the positive and negative electrode materials;

[0019] (5) Secondary injection: Inject electrolyte into the battery casing for a second time, and evacuate the inside of the battery casing with a vacuum pump and then seal it.

[0020] Furthermore, in step (3), the temperature-averaging positive plate, the separator and the temperature-averaging negative plate are arranged in sequence and stacked together layer by layer by a stacking machine to form a square stacked battery cell.

[0021] Furthermore, in step (3), the temperature-averaging positive plate, the separator, the temperature-averaging negative plate and the separator are arranged in sequence, wound and assembled into a cylindrical shape by a winding machine, and then glued and fixed into a battery cell.

[0022] The technical effects achieved by adopting the above technical solution are:

[0023] The columnar support structure of the temperature-averaging positive plate and the temperature-averaging negative plate of the present application forms a steam channel, and the transverse groove structure and the wire mesh together constitute a working fluid liquid channel to ensure that the liquid flows therein, and the gas-liquid phase change cycle improves the heat dissipation efficiency of the plate. By using the temperature-averaging positive plate with acetone injected inside as the positive electrode of the lithium battery, and using the temperature-averaging negative plate with ultrapure water injected inside as the negative electrode of the lithium battery, a positive and negative temperature-averaging plate with temperature-averaging characteristics is formed. Since the positive and negative temperature-averaging plates have high thermal conductivity and good temperature-averaging characteristics, the heat at the pole ear of the lithium battery during high-power charging can be quickly transferred to each part of the plate, and at the same time, the problem that the temperature of the upper part of the lithium battery is high and the temperature of the lower part is low during operation of the lithium battery is solved, so that the temperature of the lithium battery is uniform, thereby improving the life of the lithium battery, solving the problem that the heat dissipation and temperature-averaging effects of the existing heat dissipation scheme are not obvious due to the low thermal conductivity of the battery housing, the electrolyte and the surface coating material of the plate, and meeting the requirements of the consumer goods field, the industrial field, the energy storage field and the power system for lithium battery supercharging and balanced working temperature.

[0024] Since interconnected grooves are provided at both ends of the first transverse groove and both ends of the second transverse groove, the flow of the filled working fluid is ensured, thereby improving the heat dissipation effect.

[0025] Since the interiors of the temperature-averaging positive plate and the temperature-averaging negative plate are both in a vacuum or negative pressure state, the interior of the battery housing is in a vacuum state, thereby preventing oxidation of the electrolyte and the heat dissipation medium, thereby improving battery performance and life.

[0026] The preparation method of the lithium battery with uniform temperature characteristics of the present application has the following beneficial effects:

[0027] The preparation method of the lithium battery with uniform temperature characteristics of the present application adopts a uniform temperature positive plate with uniform temperature characteristics composed of a positive top plate with a support column structure, an aluminum wire mesh, a positive bottom plate with a transverse groove structure, and an acetone working medium; the uniform temperature negative plate with uniform temperature characteristics is composed of a negative top plate with a support column structure, a copper wire mesh, a negative bottom plate with a transverse groove structure, and an ultrapure water-shaped working medium; the uniform temperature positive plate and the uniform temperature negative plate form a uniform temperature battery cell in a certain arrangement order, avoiding the external heat dissipation of the battery caused by the high thermal resistance of the battery shell, electrolyte, and the coating materials on the surface of the positive and negative plates. At the same time, the temperature at the ear during supercharging and working can be quickly uniformized to avoid the formation of "hot spots", promote the temperature balance of the battery cell, and improve the service life of the lithium battery. The preparation method of the lithium battery with uniform temperature characteristics of the present application is realized on the basis of the existing lithium battery preparation process, making full use of the existing preparation process flow, reducing the high asset investment brought about by equipment transformation, and also more conducive to enterprise cost and quality control. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0029] Figure 1 is a schematic diagram of the battery cell structure of Example 1;

[0030] Figure 2 It is a schematic diagram of the internal structure of the temperature-averaged positive plate;

[0031] Figure 3 Schematic diagram of the structure of the positive electrode top plate;

[0032] Figure 4 It is a schematic diagram of the aluminum wire mesh structure;

[0033] Figure 5 Schematic diagram of the structure of the positive electrode bottom plate;

[0034] Figure 6 This is a schematic diagram of the battery structure of Example 2;

[0035] In the figure, 1. battery casing; 2. diaphragm; 3. tape; 4. temperature-uniform negative plate; 5. temperature-uniform positive plate; 6. negative electrode ear; 7. positive electrode ear; 8. positive electrode top plate; 9. aluminum wire mesh; 10. positive electrode bottom plate; 11. first columnar support; 12. first transverse groove; 13. interconnecting grooves. DETAILED DESCRIPTION

[0036] Embodiment 1

[0037] like Figures 1 to 5 As shown, a lithium battery with temperature-averaging characteristics includes a battery casing 1, a battery cell and an electrolyte. The battery casing 1 is fixedly provided with a battery cell, and the inner cavity of the battery casing 1 is filled with an electrolyte prepared from lithium salt and an organic solvent. The battery casing 1 is made of steel shell, aluminum shell, nickel-plated iron shell or aluminum-plastic shell.

[0038] The battery cell includes a temperature-averaging positive plate 5, a temperature-averaging negative plate 4 and a diaphragm 2. The temperature-averaging positive plate 5, the temperature-averaging negative plate 4 and the diaphragm 2 are arranged in the order of the temperature-averaging positive plate 5-diaphragm 2-temperature-averaging negative plate 4, that is, the temperature-averaging positive plate 5 and the temperature-averaging negative plate 4 are separated by the diaphragm 2. The end of the temperature-averaging positive plate 5 is provided with a positive ear 7, and the end of the temperature-averaging negative plate 4 is provided with a negative ear 6. The positive ear 7 is an aluminum ear, and the negative ear 6 is a nickel ear. The temperature-averaging positive plate 5 includes a positive top plate 8 and a positive bottom plate 10. A plurality of first columnar supports 11 are fixedly arranged on the inner side of the positive top plate. An aluminum wire mesh 9 is sandwiched between the first columnar support 11 and the positive bottom plate 10. A first transverse groove 12 parallel to the direction of the positive ear is etched on the inner side of the positive bottom plate 10. The aluminum wire mesh 9 and the first transverse groove 12 constitute a positive liquid wick structure. Acetone is filled in the chamber between the positive top plate 8 and the positive bottom plate 10. The positive electrode top plate 8 and the positive electrode bottom plate 10 of the temperature-averaging positive electrode plate 5 are made of metal aluminum. The two sides of the temperature-averaging positive electrode plate 5 are coated with a positive electrode material mixed with a lithium compound material, a binder and a conductive agent. The lithium compound material is lithium manganese oxide, lithium cobalt oxide, nickel cobalt lithium manganese oxide, lithium iron phosphate, etc.

[0039] The temperature-averaging negative plate 4 includes a negative top plate and a negative bottom plate. A plurality of second columnar supports are fixedly arranged on the inner side of the negative top plate. A copper wire mesh is arranged between the second columnar support and the negative bottom plate. A second transverse groove parallel to the negative ear direction is etched on the inner side of the negative bottom plate. The copper wire mesh and the second transverse groove constitute a negative electrode liquid wick structure. Ultrapure water is filled in the chamber between the negative top plate and the negative bottom plate. Both ends of the first transverse groove 12 and the second transverse groove are submillimeter grooves. Both ends of the first transverse groove 12 and the second transverse groove are provided with interconnecting grooves 13. The interconnecting grooves 13 can ensure the flow of the working fluid filled therein and improve the heat dissipation effect. The negative top plate and the negative bottom plate of the temperature-averaging negative plate 4 are made of metal copper. The plate surfaces on both sides of the temperature-averaging negative plate 4 are coated with a negative electrode material prepared from graphite, a binder and a conductive agent. The interior of the temperature-averaging positive plate 5 and the temperature-averaging negative plate 4 are both in a vacuum or negative pressure state, and the interior of the battery housing 1 is in a vacuum state, which avoids oxidation of the electrolyte and the heat dissipation medium and improves the battery performance and life.

[0040] The positive and negative electrode liquid wick structures of the lithium battery with temperature-averaging characteristics of the present application form working fluid liquid channels to ensure that the liquid working fluid flows therein and improve the heat dissipation efficiency. On the one hand, the first columnar support 11 and the second columnar support can play a role in supporting and preventing the plate body from collapsing. On the other hand, under the action of the first columnar support 11 and the second columnar support, gas channels are formed between the positive electrode top plate 8 and the positive electrode bottom plate 10 and between the negative electrode top plate and the negative electrode bottom plate to ensure the flow of the filled working fluid vapor and improve the heat dissipation effect. The preparation method of the lithium battery with temperature-averaging characteristics of this embodiment includes the following steps:

[0041] (1) Plate preparation: a first columnar support 11 is etched on the inner surface of the positive top plate 8, a first transverse groove with equal spacing is etched on the inner surface of the positive bottom plate 10, an aluminum wire mesh 9 is laid between the positive top plate 8 and the positive bottom plate 10, the positive top plate 8 and the positive bottom plate 10 are welded around by vacuum diffusion welding, and then acetone is injected to obtain a uniform temperature positive plate 5. A second columnar support is etched on the inner surface of the negative top plate, a second transverse groove with equal spacing is etched on the inner surface of the negative bottom plate, a copper wire mesh is laid between the negative top plate and the negative bottom plate, the negative top plate and the negative bottom plate are welded around by vacuum diffusion welding, and then ultrapure water is injected to obtain a uniform temperature negative plate 4.

[0042] (2) Plate coating: After coating both sides of the temperature-averaging positive plate 5 with positive electrode material, roll-pressing and baking are performed; after coating both sides of the temperature-averaging negative plate 4 with negative electrode material, roll-pressing and baking are performed; positive electrode tabs are welded to the temperature-averaging positive plate 5 , and negative electrode tabs are welded to the temperature-averaging negative plate 4 .

[0043] (3) Preparation of battery cells: The temperature-averaging positive electrode plate 5, the separator 2 and the temperature-averaging negative electrode plate 4 are arranged in sequence, and stacked layer by layer by a stacking machine to form a square stacked battery cell, and the packaged battery cell is loaded into the battery housing 1.

[0044] (4) Primary injection: inject electrolyte into the battery housing 1, which is then sealed with a rubber plug. After high-temperature aging treatment, the electrolyte is allowed to soak the temperature-equalizing positive plate 5, the temperature-equalizing negative plate 4 and the diaphragm 2. Pull out the rubber plug and charge the lithium battery in a constant temperature and humidity environment to activate the positive and negative electrode materials.

[0045] (5) Secondary liquid injection: electrolyte is injected into the battery housing 1 for a second time, and the interior of the battery housing 1 is evacuated and sealed by a vacuum pump.

[0046] The lithium batteries obtained through the above steps are inspected for charge and discharge, classified according to battery capacity, and placed in a 40±5°C space for high-temperature aging for a certain period of time to allow the lithium battery electrolyte to be more fully infiltrated and the SEI film to be more compact after formation. Finally, the outer surface of the battery shell 1 is inspected for appearance, sprayed with grade code, grade scanning inspection, and packaging inspection before storage, completing the preparation of lithium batteries with temperature-averaging characteristics.

[0047] Embodiment 2

[0048] like Figure 6 As shown, the structure of this embodiment is basically the same as that of embodiment 1, except that the temperature-averaging positive plate 5 and the temperature-averaging negative plate 4 are cylindrical, preferably round or square, and the temperature-averaging negative plate 4 is sleeved inside the temperature-averaging positive plate 5, a diaphragm 2 is arranged between the temperature-averaging positive plate 5 and the temperature-averaging negative plate 4, and a diaphragm 2 is arranged on the inner side of the temperature-averaging negative plate 4.

[0049] The method for preparing a lithium battery with a uniform temperature characteristic in this embodiment comprises the following steps:

[0050] (1) Plate preparation: a first columnar support 11 is etched on the inner surface of the positive electrode top plate 8, first transverse grooves 12 with equal spacing are etched on the inner surface of the positive electrode bottom plate 10, an aluminum wire mesh 9 is laid between the positive electrode top plate 8 and the positive electrode bottom plate 10, the positive electrode top plate 8 and the positive electrode bottom plate 10 are welded around by vacuum diffusion welding, and then acetone is injected to obtain a uniform temperature positive electrode plate 5; a second columnar support is etched on the inner surface of the negative electrode top plate, second transverse grooves with equal spacing are etched on the inner surface of the negative electrode bottom plate, a copper wire mesh is laid between the negative electrode top plate and the negative electrode bottom plate, the negative electrode top plate and the negative electrode bottom plate are welded around by vacuum diffusion welding, and then ultrapure water is injected to obtain a uniform temperature negative electrode plate 4.

[0051] (2) Plate coating: After coating both sides of the temperature-averaging positive plate 5 with positive electrode material, roll-pressing and baking are performed; after coating both sides of the temperature-averaging negative plate 4 with negative electrode material, roll-pressing and baking are performed; positive electrode tabs are welded to the temperature-averaging positive plate 5 , and negative electrode tabs are welded to the temperature-averaging negative plate 4 .

[0052] (3) Preparation of battery cells: Arrange the temperature-averaging positive electrode sheet 5, the diaphragm 2, the temperature-averaging negative electrode sheet 2 and the diaphragm 2 in sequence, wind them into a cylindrical shape using a winding machine, and then use tape 3 to fix them into battery cells. The packaged battery cells are loaded into the battery housing 1.

[0053] (4) Primary injection: inject electrolyte into the battery housing 1, which is then sealed with a rubber plug. After high-temperature aging treatment, the electrolyte is allowed to soak the temperature-uniform positive electrode plate 5, the temperature-uniform negative electrode plate 4 and the separator 2.

[0054] (5) Secondary liquid injection: electrolyte is injected into the battery housing 1 for a second time, and the interior of the battery housing 1 is evacuated and sealed by a vacuum pump.

[0055] The lithium batteries obtained through the above steps are inspected for charge and discharge, classified according to battery capacity, and placed in a 40±5°C space for high-temperature aging for a certain period of time to allow the lithium battery electrolyte to be more fully infiltrated and the SEI film to be more compact after formation. Finally, the outer surface of the battery shell 1 is inspected for appearance, sprayed with grade code, grade scanning inspection, and packaging inspection before storage, completing the preparation of lithium batteries with temperature-averaging characteristics.

[0056] The lithium battery with temperature equalization characteristics of the present application uses a temperature equalization positive plate 5 with acetone injected inside as the positive electrode of the lithium battery, and uses a temperature equalization negative plate 4 with ultrapure water injected inside as the negative electrode of the lithium battery, to form a positive and negative electrode temperature equalization plate with temperature equalization characteristics. Since the positive and negative electrode temperature equalization plates have high thermal conductivity and good temperature equalization characteristics, the heat at the pole ear of the lithium battery during high-power charging can be quickly transferred to every part of the plate. At the same time, it can also solve the problem that the temperature of the upper part of the lithium battery is high and the temperature of the lower part is low during operation, so that the temperature of the lithium battery is uniform, thereby improving the life of the lithium battery, avoiding the problem that the existing heat dissipation solution has low thermal conductivity of the battery casing, electrolyte and plate surface coating material, resulting in unclear heat dissipation and temperature equalization effects, and meeting the requirements of consumer products, industrial fields, energy storage fields and power systems for lithium battery supercharging and balanced operating temperature.

[0057] This application uses a temperature-averaging positive plate based on gas-liquid phase change to replace the positive electrode of the lithium battery, and a temperature-averaging negative plate based on gas-liquid phase change to replace the negative electrode of the lithium battery. The positive and negative plates are arranged in a certain way to form a battery cell. The efficient thermal conductivity and extremely high thermal conductivity of the positive and negative temperature-averaging plates can quickly average the heat accumulated near the pole ear during lithium battery overcharging and operation, achieving battery temperature reduction and temperature balance.

Claims

1. A lithium battery with a temperature-averaging characteristic, comprising a battery housing, a battery cell and an electrolyte, wherein the battery cell is fixedly arranged inside the battery housing, and the inner cavity of the battery housing is filled with an electrolyte, characterized in that: The battery cell comprises a temperature-averaging positive plate, a temperature-averaging negative plate and a diaphragm, wherein the diaphragm is arranged between the temperature-averaging positive plate and the temperature-averaging negative plate, the temperature-averaging positive plate is provided with a positive electrode ear, and the temperature-averaging negative plate is provided with a negative electrode ear. The temperature-averaging positive electrode plate comprises a positive electrode top plate and a positive electrode bottom plate, a plurality of first columnar supports are fixedly arranged on the inner side of the positive electrode top plate, an aluminum wire mesh is sandwiched between the first columnar supports and the positive electrode bottom plate, a first transverse groove is arranged on the inner side of the positive electrode bottom plate, the aluminum wire mesh and the first transverse groove constitute a positive electrode liquid wick structure, and acetone is filled in the chamber between the positive electrode top plate and the positive electrode bottom plate; The temperature-averaging negative electrode plate includes a negative electrode top plate and a negative electrode bottom plate, a plurality of second columnar supports are fixedly arranged on the inner side of the negative electrode top plate, a copper wire mesh is arranged between the second columnar support and the negative electrode bottom plate, a second transverse groove is arranged on the inner side of the negative electrode bottom plate, the copper wire mesh and the second transverse groove constitute a negative electrode liquid absorption core structure, and the chamber between the negative electrode top plate and the negative electrode bottom plate is filled with ultrapure water.

2. A lithium battery with temperature-isolating characteristics according to claim 1, characterized in that: Interconnecting grooves are provided at both ends of the first transverse groove and both ends of the second transverse groove.

3. A lithium battery with temperature-averaging characteristics according to claim 1, characterized in that: The temperature-averaging positive plate is made of metal aluminum, the temperature-averaging negative plate is made of metal copper, and the battery shell is made of steel shell, aluminum shell, nickel-plated iron shell or aluminum-plastic shell.

4. A lithium battery with temperature-averaging characteristics according to claim 1, characterized in that: The interiors of the temperature-averaging positive electrode plate and the temperature-averaging negative electrode plate are both in a vacuum or negative pressure state, and the interior of the battery housing is in a vacuum state.

5. A lithium battery with temperature-averaging characteristics according to claim 1, characterized in that: The temperature-averaging positive plate and the temperature-averaging negative plate are cylindrical, the temperature-averaging negative plate is sleeved inside the temperature-averaging positive plate, and the diaphragm is arranged between the temperature-averaging positive plate and the temperature-averaging negative plate and inside the temperature-averaging negative plate.

6. A lithium battery with temperature-averaging characteristics according to claim 1, characterized in that: The two sides of the temperature-averaging positive plate are coated with a positive electrode material mixed with a lithium compound material, a binder and a conductive agent, and the two sides of the temperature-averaging negative plate are coated with a negative electrode material mixed with graphite, a binder and a conductive agent.

7. The method for preparing a lithium battery with a uniform temperature characteristic according to claim 1, characterized in that: The following steps are involved: (1) Preparation of electrode plates: etching a first columnar support on the inner surface of the positive electrode top plate, etching a first transverse groove with equal spacing on the inner surface of the positive electrode bottom plate, laying an aluminum wire mesh between the positive electrode top plate and the positive electrode bottom plate, welding the positive electrode top plate and the positive electrode bottom plate around by vacuum diffusion welding, and then injecting acetone to obtain a uniform temperature positive electrode plate; etching a second columnar support on the inner surface of the negative electrode top plate, etching a second transverse groove with equal spacing on the inner surface of the negative electrode bottom plate, laying a copper wire mesh between the negative electrode top plate and the negative electrode bottom plate, welding the negative electrode top plate and the negative electrode bottom plate around by vacuum diffusion welding, and then injecting ultrapure water to obtain a uniform temperature negative electrode plate; (2) Plate coating: coating the positive electrode material on both sides of the uniform temperature positive electrode plate, and then rolling and baking the plate; coating the negative electrode material on both sides of the uniform temperature negative electrode plate, and then rolling and baking the plate; welding the positive electrode lug to the uniform temperature positive electrode plate, and welding the negative electrode lug to the uniform temperature negative electrode plate; (3) Preparation of battery cells: a separator is arranged between the temperature-averaging positive electrode plate and the temperature-averaging negative electrode plate obtained in step (2) to fix the obtained battery cells, and the packaged battery cells are loaded into a battery housing; (4) Primary injection: injecting electrolyte into the battery housing, then sealing it with a rubber plug, subjecting it to high temperature aging treatment so that the electrolyte infiltrates the temperature-averaged positive plate, the temperature-averaged negative plate and the separator, pulling out the rubber plug, and charging the lithium battery in a constant temperature and humidity environment to activate the positive and negative electrode materials; (5) Secondary injection: Inject electrolyte into the battery casing for a second time, and evacuate the inside of the battery casing with a vacuum pump and then seal it.

8. The method for preparing a lithium battery with a uniform temperature characteristic according to claim 7, characterized in that: In step (3), the temperature-averaging positive electrode plate, the separator and the temperature-averaging negative electrode plate are arranged in sequence and stacked together layer by layer by a stacking machine to form a square stacked battery cell.

9. The method for preparing a lithium battery with a uniform temperature characteristic according to claim 7, characterized in that: In step (3), the temperature-averaging positive plate, the separator, the temperature-averaging negative plate and the separator are arranged in sequence, wound and assembled into a cylindrical shape by a winding machine, and then glued and fixed into a battery cell.

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