A sodium-ion battery

Abstract

This invention discloses a sodium-ion battery, comprising: a casing with openings on both sides along a first direction; a cover plate covering the openings on both sides of the casing to form a receiving cavity; and an electrode assembly disposed inside the receiving cavity, the electrode assembly including a first electrode and a second electrode with opposite polarities, and a separator; the first electrode, separator, and second electrode are sequentially stacked and wound to form the electrode assembly. A heat-conducting electrode post is disposed on the cover plate, and a heat-conducting component is also disposed inside the receiving cavity, the heat-conducting component being connected to the heat-conducting electrode post. Through a specific thin-film, large-size design (W:H=4:3), combined with the characteristic of sodium-ion batteries maintaining constant thickness during charging and discharging, and employing a high-efficiency winding process, high safety and good thermal uniformity under high-rate charging and discharging are achieved.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion battery technology, specifically to a sodium-ion battery. Background Technology

[0002] Sodium-ion batteries have broad application prospects in energy storage power stations and electric vehicles due to the abundance of sodium resources, low cost, and good performance at high and low temperatures and in terms of safety. However, the current mainstream sodium-ion square battery structure mostly follows the design of lithium-ion batteries, which fails to fully adapt to the material and electrochemical characteristics of sodium-ion batteries themselves.

[0003] Specifically, in lithium-ion batteries, the graphite anode undergoes significant volume changes during lithium insertion and extraction, leading to periodic fluctuations in cell thickness. This limits the development of ultra-thin, large-area structures and places high demands on assembly pressure management; improper management can easily lead to safety hazards such as lithium plating. In contrast, sodium-ion batteries primarily use adsorption and pore filling for sodium insertion in the anode, resulting in minimal thickness changes during charge and discharge. This provides a feasible basis for large-size, thin-thickness battery structures from a material mechanism perspective.

[0004] While existing thin-film batteries have made some attempts to improve volumetric energy density, they mostly employ a stacking process, which involves large equipment investment, low production efficiency, and high manufacturing costs. Furthermore, traditional wound batteries require electrode die-cutting to form tabs, a complex process that easily generates metal burrs, posing a risk of internal short circuits. Simultaneously, during high-rate operation, internal heat generation is concentrated, and external heat dissipation methods are insufficient to effectively manage the temperature of the core area, affecting performance and cycle life.

[0005] Therefore, a new battery structure optimized for the characteristics of sodium-ion batteries is needed, which takes into account efficient thermal management, improved intrinsic safety, simplified process and improved space utilization, so as to give full play to the technical and economic advantages of sodium-ion batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a sodium-ion battery that addresses the problems of existing sodium-ion battery structures failing to fully utilize their material advantages, insufficient thermal management efficiency, safety risks and high costs associated with the tab manufacturing process, and the need to improve space utilization.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A sodium-ion battery, comprising: The housing has openings on both sides along a first direction; A cover plate covers the openings on both sides of the housing to form an accommodating cavity; An electrode assembly is disposed inside the accommodating cavity. The electrode assembly includes a first electrode and a second electrode with opposite polarities, and a diaphragm. The first electrode, the diaphragm, and the second electrode are sequentially stacked and wound to form the electrode assembly. The first electrode has a first electrode body region and a first electrode tab, and the second electrode has a second electrode body region and a second electrode tab. The shell has a first distance along a first direction, a second distance along a second direction, and a third distance along a third direction; the first direction, the second direction, and the third direction are mutually perpendicular; the ratio of the second distance to the first distance is 4:3; The first electrode body region has a width W1 along the second direction, and the first electrode tab has a width W2 along the second direction, where 80% ≤ W2 / W1 ≤ 90%; A heat-conducting electrode is provided on the cover plate, and a heat-conducting component is also provided inside the accommodating cavity. The heat-conducting component is connected to the heat-conducting electrode.

[0008] Furthermore, the electrode assembly includes a plurality of individual coils stacked along the third direction, and the heat-conducting element is disposed between two adjacent individual coils.

[0009] Furthermore, both the first electrode and the second electrode include a current collector, an active layer, and a ceramic region; the current collector is an aluminum foil, the active layer is disposed on the surface of the aluminum foil, and the ceramic region is disposed on both sides of the active layer along the first direction.

[0010] Furthermore, the cover plate includes a first cover plate and a second cover plate; the first cover plate is provided with the heat-conducting electrode post, and the heat-conducting electrode post is disposed through the first cover plate; a first groove is provided on the surface of the first cover plate near the electrode assembly; one end of the heat-conducting element is disposed in the first groove.

[0011] Furthermore, the heat-conducting component includes a main heat-conducting component area and a heat-conducting component connecting section; the first groove has a first width along the first direction, and the heat-conducting component connecting section has a second width along the first direction, wherein the first width is greater than the second width.

[0012] Furthermore, a sensor is provided on the heat-conducting component, and adhesive is provided in the first groove.

[0013] Furthermore, both the first cover plate and the second cover plate are provided with through holes; the signal line of the sensor is led out from the through holes.

[0014] Furthermore, an explosion-proof valve is also provided on the first cover plate.

[0015] Furthermore, the second cover plate is also provided with an injection hole.

[0016] An electrical device comprising a plurality of the aforementioned sodium-ion batteries.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves high safety and good thermal balance under high-rate charging and discharging by using a specific thin and large-size design (W:H=4:3) and the characteristic of sodium-ion batteries that the thickness remains unchanged during charging and discharging.

[0018] 2. This invention, through its innovative "foil-ceramic-material zone-ceramic" electrode design, ensures that during production and winding, the slitting and burr-prone areas are all insulated ceramic coating zones, fundamentally avoiding internal short circuits caused by burrs and improving battery safety and cycle life.

[0019] 3. This invention constructs an efficient internal and external heat conduction channel by connecting the built-in heat-conducting plate and the heat-conducting electrode of the cover plate. It can monitor and transfer the internal heat of the battery cell in real time. Combined with the external liquid cooling system, it can achieve precise temperature control, prevent thermal runaway, and further improve rate performance.

[0020] 4. This invention adopts a full tab winding structure, which eliminates the tab die-cutting process. The electrode design reduces material waste from slitting and improves the yield. The winding process itself has lower equipment investment and higher efficiency compared to the stacking process, thereby significantly reducing the overall manufacturing cost and pack cost of the battery.

[0021] 5. The flat rectangular structure of this invention can be flexibly designed according to the space and working conditions of different application scenarios (such as energy storage and heavy trucks), thereby improving space utilization and adaptability. Attached Figure Description

[0022] Figure 1 This is a side view of the negative electrode of a single cell in this invention; Figure 2 This is a side view of the positive electrode of a single cell of the present invention; Figure 3 This is a schematic diagram of the internal structure of a single battery cell of the present invention; Figure 4 This is an exploded view of a single battery cell of the present invention; Figure 5 This is a schematic diagram of the internal structure of a single core of the present invention; Figure 6 This is a schematic diagram of the positive electrode cover plate structure of the present invention; Figure 7 This is a schematic diagram of the positive electrode cover plate structure of the present invention; Figure 8 This is a schematic diagram of the negative electrode cover plate structure of the present invention; Figure 9 This is a schematic diagram of the negative electrode cover plate structure of the present invention; Figure 10 This is a schematic diagram of the heat-conducting plate structure of the present invention; Figure 11This is a schematic diagram of the existing double-strip positive electrode production method; Figure 12 This is a schematic diagram of the production method of the dual-strip positive and negative electrode sheets of the present invention; Figure 13 This is a schematic diagram of the positive and negative electrodes and the separator assembled according to the present invention.

[0023] Figure label: 100. Housing; 200. First cover plate; 201. Positive electrode post tab welding area; 202. First connection area; 203. Outer side of the positive electrode cover plate heat-conducting post; 204. Heat-conducting post; 205. First retainer; 206. Liquid injection hole; 300. Second cover plate; 301. Negative electrode post tab welding area; 302. Explosion-proof valve retainer; 303. Second connection area; 304. Retainer body; 305. Negative electrode post; 306. Explosion-proof valve; 307. Outside of the negative electrode cover heat-conducting electrode post; 400. Electrode assembly; 401. Finishing adhesive; 402. First tab; 403. Second tab; 500. Heat-conducting component; 501. High-viscosity heat-conducting adhesive coating; 502. Heat-conducting component connecting section; 1101. Foil current collector; 1102. Ceramic area; 1103. Active layer; 1104. Cut edge. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figure 1-13This embodiment provides a sodium-ion battery, including a housing 100, a cover plate, and an electrode assembly 400. The housing 100 has a rectangular structure with openings on both sides along its length. The cover plate covers the openings on both sides of the housing 100, forming a sealed accommodating cavity. The electrode assembly 400 is disposed inside the accommodating cavity and includes a first electrode and a second electrode with opposite polarities, as well as a separator. The electrode assembly is formed by a winding process. The first electrode has a first electrode body area and a first electrode tab 402, and the second electrode has a second electrode body area and a second electrode tab 403. The dimensions of the housing 100 are [not specified in the original text]. The first distance along the first direction is 420mm, the second distance along the second direction is 348mm, and the third distance along the third direction is 38mm. The ratio of the second distance to the first distance is 4:3. The ratio of the width W2 of the first electrode tab 402 to the width W1 of the first electrode body area satisfies 80%≤W2 / W1≤90% to achieve efficient current transmission. A heat-conducting electrode post is provided on the cover plate, and a heat-conducting component 500 is also provided inside the accommodating cavity. The heat-conducting component 500 is connected to the heat-conducting electrode post to conduct the heat generated by the electrode assembly 400 and optimize the thermal management performance of the battery.

[0026] As an improvement, the electrode assembly 400 is composed of multiple individual cores stacked along a third direction. A heat-conducting element 500 is provided between adjacent individual cores to conduct heat between the individual cores. The heat-conducting element 500 is made of silicon-based composite material and is coated with high-viscosity thermally conductive adhesive. It achieves a stable connection with the thermally conductive electrode through a groove embedded in the cover plate.

[0027] Furthermore, both the first electrode and the second electrode include an aluminum foil current collector 1101, an active layer 1103 coated on the surface of the aluminum foil, and ceramic regions 1102 disposed on both sides of the active layer 1103. The ceramic regions 1102 are provided to avoid burrs generated during the cutting process, thereby preventing battery short circuits and improving safety.

[0028] Furthermore, the cover plate is divided into a first cover plate 200 and a second cover plate 300. A through-through heat-conducting electrode post 204 is provided on the first cover plate 200. A first groove is opened on the side surface near the electrode assembly 400. One end of the heat-conducting component 500 is embedded in the first groove. Through structural fit and high-viscosity heat-conducting adhesive, a tight connection is achieved to ensure the stability of heat conduction.

[0029] The heat-conducting component 500 includes a heat-conducting component main area and a heat-conducting component connecting section 502. The first width of the first groove along the first direction is greater than the second width of the heat-conducting component connecting section 502 along the first direction. This design allows the heat-conducting component connecting section 502 to be securely embedded in the first groove, preventing it from loosening during battery use.

[0030] As an improvement, a temperature sensor is provided on the heat-conducting component 500 to monitor the temperature of the electrode assembly in real time. The first groove is filled with high-viscosity thermally conductive adhesive to ensure the heat conduction efficiency between the heat-conducting component and the cover plate, while also fixing the position of the sensor.

[0031] Furthermore, both the first cover plate 200 and the second cover plate 300 have through holes, through which the sensor signal lines are led out and connected to an external temperature control system to realize real-time monitoring and adjustment of the battery's internal temperature.

[0032] Furthermore, the first cover plate 200 is also equipped with an explosion-proof valve 306. The opening pressure of the explosion-proof valve 306 is 0.8±0.2Mpa, which ensures that the pressure inside the battery can be released in time when there is an abnormality, thereby improving the safety of the battery.

[0033] The second cover plate 300 is also provided with an injection hole 206, which is used to inject electrolyte into the accommodating cavity. After the electrolyte is injected, it is sealed by welding with a sealing nail to ensure the battery's airtightness.

[0034] In addition, this embodiment provides an electrical device including multiple sodium-ion batteries connected in series or in parallel, suitable for energy storage systems or heavy trucks, and leveraging the advantages of high rate of operation, high safety and high energy density.

[0035] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A sodium-ion battery, characterized in that, include: The housing has openings on both sides along a first direction; A cover plate covers the openings on both sides of the housing to form an accommodating cavity; An electrode assembly is disposed inside the accommodating cavity. The electrode assembly includes a first electrode and a second electrode with opposite polarities, and a diaphragm. The first electrode, the diaphragm, and the second electrode are sequentially stacked and wound to form the electrode assembly. The first electrode has a first electrode body region and a first electrode tab, and the second electrode has a second electrode body region and a second electrode tab. The shell has a first distance along a first direction, a second distance along a second direction, and a third distance along a third direction; the first direction, the second direction, and the third direction are mutually perpendicular; the ratio of the second distance to the first distance is 4:3; The first electrode body region has a width W1 along the second direction, and the first electrode tab has a width W2 along the second direction, where 80% ≤ W2 / W1 ≤ 90%; A heat-conducting electrode is provided on the cover plate, and a heat-conducting component is also provided inside the accommodating cavity. The heat-conducting component is connected to the heat-conducting electrode.

2. A sodium-ion battery according to claim 1, characterized in that: The electrode assembly includes a plurality of individual coils stacked along the third direction, and the heat-conducting element is disposed between two adjacent individual coils.

3. A sodium-ion battery according to claim 1, characterized in that: Both the first electrode and the second electrode include a current collector, an active layer, and a ceramic region; the current collector is an aluminum foil, the active layer is disposed on the surface of the aluminum foil, and the ceramic region is disposed on both sides of the active layer along the first direction.

4. A sodium-ion battery according to claim 3, characterized in that: The cover plate includes a first cover plate and a second cover plate; the first cover plate is provided with the heat-conducting electrode post, and the heat-conducting electrode post is disposed through the first cover plate; a first groove is provided on the side surface of the first cover plate near the electrode assembly; one end of the heat-conducting element is disposed in the first groove.

5. A sodium-ion battery according to claim 1, characterized in that: The heat-conducting component includes a main heat-conducting component area and a heat-conducting component connecting section; the first groove has a first width along the first direction, and the heat-conducting component connecting section has a second width along the first direction, wherein the first width is greater than the second width.

6. A sodium-ion battery according to claim 5, characterized in that: A sensor is installed on the heat-conducting component, and adhesive is installed in the first tank.

7. A sodium-ion battery according to claim 1, characterized in that: Both the first cover plate and the second cover plate are provided with through holes; the signal line of the sensor is led out from the through holes.

8. A sodium-ion battery according to claim 1, characterized in that: An explosion-proof valve is also provided on the first cover plate.

9. A sodium-ion battery according to claim 1, characterized in that: The second cover plate is also provided with an injection hole.

10. An electrical device comprising a plurality of sodium-ion batteries according to any one of claims 1-9.

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