Negative pressure encapsulated soft-packaged zinc-air battery power bank and preparation method thereof

Abstract

This invention relates to the field of zinc-air battery energy storage technology, specifically disclosing a negative pressure encapsulated soft-pack zinc-air battery power bank and its preparation method. The power bank includes a zinc-air battery cell assembly and a packaging bag covering the zinc-air battery cell assembly. The inside of the packaging bag is under vacuum negative pressure, allowing the inner surface of the packaging bag to adhere to the outer surface of the zinc-air battery cell assembly. This invention relies on a vacuum negative pressure structure design to ensure the packaging bag is completely and tightly attached to the power bank body. When a small amount of electrolyte leaks from the cell, the alkaline-sensitive pH-changing layer inside the packaging bag causes the surface at the leak point to darken due to electrolyte wetting. The alkaline electrolyte, upon contact with the color-changing layer, produces a noticeable color change, allowing for visual identification of the leakage fault. The entire detection process does not require disassembly, significantly improving the efficiency of each step of the inspection. This accelerates the detection of leaking zinc-air batteries and prevents air from entering the cell, thus preventing battery failure.

Description

Technical Field

[0001] This invention relates to the field of zinc-air battery energy storage technology, specifically to a negative pressure encapsulated soft-pack zinc-air battery power bank and its preparation method. Background Technology

[0002] Zinc-air batteries are a type of metal-air chemical power source that uses metallic zinc as the negative electrode active material and oxygen from ambient air as the positive electrode active material. They possess significant advantages such as high energy density, low raw material cost, stable discharge performance, and environmental friendliness. They are often manufactured as disposable, unactivated energy storage power banks and are widely used in emergency power supply, outdoor travel, backup power, and many other scenarios. Because zinc-air batteries rely on oxygen to participate in the electrochemical reaction for discharge, the product must be strictly isolated from air before activation to prevent premature self-discharge and failure.

[0003] Currently, zinc-air batteries and their products generally adopt atmospheric pressure heat sealing. For example, for button-type zinc-air batteries, the industry generally believes that atmospheric pressure sealing is more advantageous than vacuum sealing. First, under negative pressure, the expansion of air bubbles inside the cell can easily cause the electrolyte to permeate out of the permeable layer, causing the battery to fail. Second, the amount of residual oxygen inside the heat-sealed bag is very limited, and after reacting with the cell, it will not continue to affect the product performance. Finally, adding an extra vacuuming process will increase equipment investment and production costs, making it not cost-effective. Therefore, existing products usually put the cell and the permeable packaging shell into a heat-sealed bag and then directly heat-seal it under atmospheric pressure to complete the product packaging.

[0004] However, in practical applications and long-term research and development, it has been found that soft-pack zinc-air batteries and their products have intractable technical defects in the atmospheric pressure packaging scheme: First, zinc-air batteries have a probability of electrolyte leakage. Under atmospheric pressure, the breathable packaging shell inside the bag has a buffer space, and the leaked electrolyte will be completely absorbed and hidden by the breathable packaging shell. The outer packaging does not show obvious deformation or appearance changes, but it is easy to seep into the hands when opened for use. The leakage defect is extremely hidden and difficult to quickly identify in the warehousing, transportation and factory quality inspection stages, posing a significant safety hazard. Second, leakage of zinc-air batteries is difficult to detect. It is a slow seepage phenomenon. Under atmospheric pressure, this leakage may not be discovered for 1-3 months. By the time it is discovered, it has already entered the hands of customers. Third, when producing soft-pack zinc-air battery products, our company found that when the soft-pack zinc-air battery products are stored for 3 months or more, the air remaining in the packaging bag will slowly enter between the positive electrode and the separator of the battery during long-term storage, resulting in a shortened product storage life and inability to be activated and used normally. Summary of the Invention

[0005] The present invention provides a negative pressure encapsulated soft-pack zinc-air battery power bank, comprising a soft-pack zinc-air battery cell assembly, a breathable diffusion layer, and an encapsulation bag covering the outside of the zinc-air battery cell assembly. The zinc-air battery cell pack uses a pouch zinc-air battery. The inside of the packaging bag is under vacuum negative pressure so that the inner surface of the packaging bag is in contact with the outer surface of the zinc-air battery cell pack.

[0006] Preferably, the inner surface of the packaging bag is coated with an alkali-sensitive pH color-changing layer. When electrolyte leakage occurs in the zinc-air battery cell assembly, the alkali-sensitive pH color-changing layer can change color when it comes into contact with alkaline electrolyte.

[0007] Preferably, the zinc-air battery cell pack includes at least one zinc-air cell, and the zinc-air cell includes a battery casing, a zinc negative electrode and an air positive electrode disposed within the battery casing.

[0008] Preferably, the covering shell is made of flexible plastic film.

[0009] Preferably, the number of zinc-air cells is at least two, and the multiple zinc-air cells are connected in series.

[0010] Preferably, the multiple zinc-air cells are arranged symmetrically in two rows, and the positive air electrode side of all zinc-air cells faces outward.

[0011] Preferably, the zinc-air battery cell pack has a breathable diffusion layer on both the top and bottom surfaces.

[0012] Preferably, the zinc-air battery cell pack also includes a housing, which includes an upper housing and a lower housing. The upper housing and the lower housing are sealed together by heat pressing to form the housing. Multiple zinc-air individual cells and a breathable diffusion layer are enclosed inside the housing.

[0013] Preferably, the packaging bag is a heat-sealable plastic bag, and the opening of the packaging bag is sealed by heat pressing to form a closed cavity.

[0014] Preferably, a method for preparing a negative pressure encapsulated soft-pack zinc-air battery power bank includes the following steps: S1: Prefabricated zinc-air battery cell packs are arranged and packed into packaging bags. S2: Vacuum treatment is performed on the internal cavity of the packaging bag to reduce the pressure inside the bag to a preset negative pressure value, thereby driving the inner bag surface of the packaging bag to completely adhere to the outer surface of the zinc-air battery cell pack. S3: Maintain a vacuum negative pressure state, perform heat sealing on the opening of the packaging bag, and obtain the finished vacuum-sealed zinc-air battery power bank after cooling.

[0015] The beneficial effects of this invention are: 1. This invention relies on a vacuum negative pressure structure design to ensure that the packaging bag is completely and tightly attached to the power bank body. When a small amount of electrolyte leaks from the battery cell, the leaked liquid is directly between the inner wall of the packaging bag and the zinc-air battery cell assembly. The surface of the leaking area darkens in color due to electrolyte wetting, making the leakage fault quickly and intuitively identifiable with the naked eye. When combined with the alkaline-sensitive pH color-changing layer inside the packaging bag, the alkaline electrolyte will also produce a noticeable color change upon contact with the color-changing layer. The entire detection process does not require unpacking and can be directly applied to factory quality inspection, warehousing sorting, and transportation inspection, significantly improving the inspection efficiency of each stage and completely solving the common problem in the industry that minor leaks are highly concealed and difficult to detect.

[0016] 2. Electrolyte leakage in zinc-air batteries under normal pressure packaging is a slow permeation process. Leaking cells caused by micropore defects in the breathable membrane or insufficient sealing during hot-pressing typically take 1-2 months to show identifiable leakage characteristics on the outer packaging. This significant delay in defect detection means quality problems often only become apparent after the product has reached the customer. This invention employs a vacuum negative pressure packaging structure. The negative pressure environment accelerates electrolyte permeation and diffusion. Products with potential leakage can show leakage defects within one week through packaging bag deformation. This allows for defective product screening and interception during factory quality inspection, preventing leaking products from entering the market and significantly improving product qualification rates and overall quality control efficiency.

[0017] 3. After vacuuming, there is no residual air inside the packaging bag, which eliminates the path for gas to slowly seep into the positive electrode and the separator from the source. This avoids the self-discharge and cell bulging problems caused by oxygen participating in the electrochemical reaction in advance during long-term storage, effectively extending the storage life and shelf life of the zinc-air battery power bank and improving the reliability of the product during long-term storage.

[0018] 4. Vacuum sealing ensures that the packaging bag fits tightly against the battery cell, eliminating the air gap between the packaging bag and the battery cell under normal pressure sealing. This significantly reduces the overall size of the product and greatly increases the product loading capacity per unit storage and transportation space. In the same size packaging box, the product loading capacity can be increased from 10 to 15, effectively reducing the transportation and storage packaging costs per unit product. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the internal structure of the zinc-air cell battery of the present invention.

[0020] Figure 2 This is a schematic diagram of the zinc-air battery cell assembly structure of the present invention.

[0021] Figure 3 This is a schematic diagram of the vacuum-sealed structure of the present invention.

[0022] Figure label: 10. Zinc-air battery cell assembly; 20. Breathable diffusion layer; 30. Casing; 40. Packaging bag. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] Example 1: like Figures 1 to 3 As shown, this embodiment provides a negative pressure encapsulated soft-pack zinc-air battery power bank, including a zinc-air battery cell assembly 10, a breathable diffusion layer 20, and an encapsulation bag 40 covering the outside of the zinc-air battery cell assembly 10. The zinc-air battery cell pack 10 uses a soft-pack zinc-air battery. The internal cavity of the encapsulation bag 40 is in a vacuum negative pressure state. Under atmospheric pressure, the inner surface of the encapsulation bag 40 is completely attached to the outer surface of the zinc-air battery cell pack 10, forming a tightly wrapped vacuum-sealed structure.

[0025] The packaging bag 40 is a flexible and deformable heat-sealable plastic bag made of a plastic composite film with high oxygen barrier properties. It has good flexibility and heat-sealing performance. The opening of the packaging bag 40 is sealed by heat and pressure to form a closed internal cavity, ensuring the airtightness of the cavity and preventing the entry of external air. Since the inside of the packaging bag 40 is a vacuum environment and the bag body is tightly attached to the surface of the zinc-air battery cell pack 10, the inner surface of the packaging bag 40 is coated with an alkali-sensitive pH color-changing layer. The alkali-sensitive pH color-changing layer is made of pH-sensitive ink that can change color significantly when it comes into contact with alkaline electrolyte. When electrolyte leakage occurs, after the alkaline electrolyte comes into contact with the alkali-sensitive pH color-changing layer, it will produce a conspicuous color change in the leakage area. This, together with the deformation amplification effect brought about by the vacuum negative pressure, forms a dual indication, further improving the detection sensitivity of trace leakage, and facilitating the rapid identification of defective products in the quality inspection, warehousing, and transportation stages.

[0026] Furthermore, the zinc-air battery cell pack 10 contains four zinc-air cells. Multiple zinc-air cells are connected in series through a conductive structure to improve the overall output voltage and meet the power supply requirements of the power bank. Each zinc-air cell includes a battery pack shell, a zinc negative electrode, an air positive electrode and an alkaline electrolyte disposed within the battery pack shell. The zinc anode serves as the negative electrode active material of the battery, while the air cathode serves as the positive electrode reaction site. Discharge is achieved by relying on external oxygen to participate in the electrochemical reaction. The air cathode is positioned facing the outer end face of the single cell to ensure full contact with the outside air during use. The battery pack casing of the zinc-air single cell is sealed by heat pressing to form a sealed structure, which seals the zinc negative electrode, air positive electrode and alkaline electrolyte inside the battery pack casing.

[0027] Furthermore, the four zinc-air cells are arranged symmetrically in two rows, with two cells in each row. The positive air electrode side of all zinc-air cells faces the outside of the zinc-air battery cell assembly 10. The upper and lower surfaces of the zinc-air battery cell assembly 10 are covered with a permeable diffusion layer 20, which corresponds to the positive air electrode of the upper and lower rows of cells, forming an integral gas diffusion layer structure to further optimize the air diffusion effect. The breathable diffusion layer 20 is preferably made of mesh fabric with uniformly distributed breathable pores on the fabric surface. As a gas diffusion channel, it can make the incoming air diffuse evenly to the entire reaction surface of the positive air electrode, ensuring a stable and uniform discharge process. The zinc-air battery cell pack also includes a housing 30, which includes an upper housing and a lower housing. The upper housing and the lower housing are sealed together by heat pressing to form an integral housing 30. The housing 30 is preferably made of non-woven fabric. Multiple zinc-air single cells and a breathable diffusion layer 20 are wrapped inside the housing 30, thereby fixing them together to form a complete zinc-air battery cell pack 10.

[0028] The method for preparing the vacuum-sealed zinc-air battery power bank in this embodiment includes the following steps: S1: Prefabricated Zinc-Air Battery Cell Pack 10 First, individual zinc-air cells are prepared: the zinc negative electrode, air positive electrode, and alkaline electrolyte are assembled into the battery pack shell, and the periphery of the battery pack shell is heat-sealed to obtain a sealed zinc-air cell, ensuring that the air positive electrode faces the outer end face of the zinc-air cell. Four prepared zinc-air cells are connected in series and a charging cable is connected. The series-connected battery pack is arranged symmetrically in two rows, so that the air positive electrode of all zinc-air cells faces the outer end face. With all sides facing outwards, a layer of mesh fabric is laid on the top and bottom sides of the arranged battery pack as a breathable diffusion layer 20. After smoothing, the whole pack is inserted into the non-woven fabric shell 30. The non-woven fabric shell 30 is then heat-sealed around its perimeter to fix and cover the internal structure, resulting in a pre-fabricated zinc-air battery cell pack 10. At the same time, a pre-fabricated encapsulation bag 40 is also prepared: an alkali-sensitive pH color-changing ink is uniformly coated on the inner surface of the encapsulation bag 40. After drying and curing, the bag is made with an opening at one end, resulting in an encapsulation bag 40 with an alkali-sensitive color-developing layer inside.

[0029] S2: Bagging and Vacuuming After the prefabricated zinc-air battery cell assembly 10 is flattened, it is inserted into the packaging bag 40 from the opening. The position of the zinc-air battery cell assembly 10 is adjusted to be placed in the center. The vacuuming equipment is started to vacuum the internal cavity of the packaging bag 40, gradually extracting the residual air in the bag and reducing the pressure inside the bag to a preset negative pressure value. Under the pressure difference between the negative pressure and the external atmospheric pressure, the flexible packaging bag 40 gradually shrinks and tightens, so that the inner bag surface of the packaging bag is completely attached to the outer surface of the zinc-air battery cell assembly 10, and all the air inside the bag is expelled.

[0030] S3: The hot-press sealing process maintains the vacuum negative pressure inside the packaging bag 40. The opening of the packaging bag is sent into the heat sealing equipment, and the opening is hot-pressed to form an airtight seal structure. After the hot pressing is completed, the pressure is maintained for cooling and shaping, and the vacuum-sealed zinc-air battery power bank is obtained.

[0031] Example 2: This embodiment provides a basic vacuum-sealed zinc-air battery power bank, whose overall structure is basically the same as that of Embodiment 1, except that the inner surface of the packaging bag 40 in this embodiment does not have an alkali-sensitive pH color-changing layer.

[0032] In this embodiment, the packaging bag 40 is made of ordinary high-barrier plastic composite film with no additional coating on the inner surface. Leakage detection is achieved solely by the deformation effect of the bag body caused by vacuum negative pressure. When electrolyte leakage occurs in the zinc-air battery cell pack 10, the leaked electrolyte directly expands the tightly sealed packaging bag 40, forming a local bulge deformation. Leakage defects can be identified by visually observing the deformation.

[0033] This embodiment simplifies the preparation process and material costs of the packaging bag, making it suitable for general scenarios that are cost-sensitive and require mass production. It also possesses the core advantages of vacuum packaging, such as long-term storage and high space utilization in transportation.

[0034] Example 3: This embodiment is basically the same as the structure of Embodiment 1, except that the number of zinc-air cells can be flexibly configured according to the output voltage and capacity requirements. It can be 2, 6, 8, etc., or it can be connected in parallel or in a series-parallel hybrid manner, all of which fall within the protection scope of this invention.

[0035] To fully demonstrate that negative pressure accelerates the exposure of battery cells with leakage issues, 100 power banks were made, some using normal pressure packaging and some using negative pressure packaging. The following test data were obtained: As can be seen from the table, under negative pressure packaging, batteries with leakage problems will show up within a week. Negative pressure packaging does not increase the probability of cell leakage, allowing problematic zinc-air battery power banks to be intercepted before leaving the factory.

[0036] To fully demonstrate the beneficial effects of vacuuming on the air in flexible zinc packs, the following tests were conducted: Traditional rigid casings do not require vacuuming and will not bulge even after long-term storage because the internal space is fixed and gas cannot enter. In contrast, with soft casings, gas can easily enter the interior from the heat-sealed bag. This invention uses a vacuum negative pressure encapsulation soft-pack structure, which retains the low cost and lightweight characteristics of soft casings while ensuring that the packaging bag fits tightly against the surface of the battery cell through the vacuum negative pressure environment inside the bag. This fundamentally blocks the path of external gas to seep into the battery cell, preventing gas from accumulating between the positive electrode and the separator and causing bulging failure. This allows the long-term storage performance of the soft-pack zinc-air battery to reach a level comparable to that of a rigid casing structure. At the same time, it also has the advantage of visual leakage detection, allowing battery cells with leakage problems to be exposed before leaving the factory.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A negative pressure encapsulated soft-pack zinc-air battery power bank, characterized in that, It includes a zinc-air battery cell assembly (10), a breathable diffusion layer (20), and a packaging bag (40) covering the outside of the zinc-air battery cell assembly (10). The zinc-air battery cell assembly (10) uses a soft-pack zinc-air battery. The inside of the packaging bag (40) is in a vacuum negative pressure state so that the inner surface of the packaging bag (40) is attached to the outer surface of the zinc-air battery cell assembly (10).

2. The negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 1, characterized in that, The inner surface of the packaging bag (40) is coated with an alkali-sensitive pH color-changing layer. When electrolyte leakage occurs in the zinc-air battery cell assembly (10), the alkali-sensitive pH color-changing layer can change color when it comes into contact with alkaline electrolyte.

3. The negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 1, characterized in that, The zinc-air battery cell pack (10) includes at least one zinc-air cell, which includes a battery pack casing, a zinc negative electrode and an air positive electrode disposed within the battery pack casing.

4. A negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 3, characterized in that, The number of zinc-air cells is at least two, and multiple zinc-air cells are connected in series.

5. A negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 4, characterized in that, The zinc-air cells are arranged symmetrically in two rows, and the positive air electrode side of all zinc-air cells faces outward.

6. A negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 4, characterized in that, The zinc-air battery cell assembly (10) has a breathable diffusion layer (20) on both the upper and lower surfaces.

7. A negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 6, characterized in that, The zinc-air battery cell assembly (10) also includes a housing (30), which includes an upper shell and a lower shell. The upper shell and the lower shell are sealed together by hot pressing to form the housing (30). Multiple zinc-air single cells and a breathable diffusion layer (20) are enclosed inside the housing (30).

8. A negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 1, characterized in that, The packaging bag (40) is a heat-sealed plastic bag, and the opening of the packaging bag (40) is sealed by heat pressure to form a closed cavity.

9. A negative pressure encapsulated soft-pack zinc-air battery power bank according to claim 3, characterized in that, The battery pack casing is made of a soft plastic film.

10. A method for preparing a soft-pack zinc-air battery power bank with negative pressure encapsulation as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Prefabricate zinc-air battery cell assembly (10), and pack the zinc-air battery cell assembly (10) into a packaging bag (40) after tidying it up; S2: Vacuum treatment is performed on the internal cavity of the packaging bag (40) to reduce the pressure inside the bag to a preset negative pressure value, thereby driving the inner bag surface of the packaging bag (40) to completely adhere to the outer surface of the zinc-air battery cell assembly (10). S3: Maintain a vacuum negative pressure state, perform heat sealing on the opening of the packaging bag (40), and obtain the finished product of vacuum-sealed zinc-air battery power bank after cooling.

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