Battery and energy storage device

Abstract

The invention relates to a battery and an energy storage device. The battery comprises a plurality of single batteries, and the single batteries are sequentially stacked in a preset direction to form a battery module; wherein the charging cut-off voltage of each battery monomer is smaller than the positive and negative electrode gassing voltage of the battery monomer. Thus, the charging cut-off voltage of each battery monomer is kept to be smaller than the gassing voltage of the positive electrode and the negative electrode, so that each battery monomer is in an efficient charging and discharging state of 90% or above in the whole charging period, the problems of thermal runaway and thermal deformation of the battery, oxidation loss of a positive electrode current collector and the like are solved, and the service life of the battery is greatly prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery and an energy storage device. BACKGROUND

[0002] The bipolar battery is a new type of internal structure battery in chemical batteries, and the core technology is to coat positive and negative active materials on two sides of a substrate with good conductivity to replace the positive and negative two battery plates in the conventional battery structure. The new type of internal structure battery can greatly simplify the battery structure, and can cancel the components such as the tab, the pole, the internal and external connecting wires, etc., thereby reducing about 30% of the materials and weight, and significantly reducing the battery internal resistance and the battery manufacturing cost. The technology can be widely applied in lithium, lead, zinc, nickel-based primary and secondary batteries, and is very suitable for high-current and fast charging and discharging scenes, so it is an ideal new type of structure battery for the energy storage industry, and has good industrial development prospects.

[0003] The existing lead-based battery is prone to thermal runaway, thermal deformation and positive current collector oxidation during charging, which seriously affects the charging and discharging efficiency and service life of the lead-based battery. SUMMARY

[0004] Therefore, it is necessary to provide a battery and an energy storage device to improve the above defects in view of the problems that the existing lead-based battery is prone to thermal runaway, thermal deformation and positive current collector oxidation during charging, resulting in low charging and discharging efficiency and short service life of the lead-based battery.

[0005] A battery includes a plurality of battery monomers, each of the battery monomers being stacked in a preset direction to form a battery module.

[0006] Each of the battery monomers has a charging cutoff voltage less than the gas evolution voltage of the positive and negative electrodes.

[0007] In one embodiment, the output voltage of the battery is 12V, and the battery includes 7 battery monomers.

[0008] In one embodiment, each of the battery monomers includes a packaging frame, a first isolation film, a second isolation film and a bipolar plate.

[0009] The packaging frame has a receiving cavity, a first opening and a second opening on opposite sides of the packaging frame, and the bipolar plate is arranged in the receiving cavity; the first isolation film is arranged at the first opening, and the second isolation film is arranged at the second opening.

[0010] In one embodiment, the bipolar plate includes a substrate, a positive current collector, a negative current collector, a positive active material layer and a negative active material layer.

[0011] The substrate is arranged in the accommodating cavity, the positive electrode current collector is arranged on one side of the substrate facing the first opening, and the negative electrode current collector is arranged on one side of the substrate facing the second opening.

[0012] The positive electrode active material layer is arranged on one side of the negative electrode current collector away from the substrate, and the negative electrode active material layer is arranged on one side of the negative electrode current collector away from the substrate.

[0013] In one embodiment, the surface of the positive electrode current collector is provided with an oxidation-resistant layer capable of conducting electricity.

[0014] In one embodiment, the oxidation-resistant layer is a multi-element alloy layer including at least tin and bismuth.

[0015] In one embodiment, the negative electrode current collector is a copper foil layer; the surface of the negative electrode current collector is provided with a corrosion-resistant layer resistant to electrolyte corrosion, and the corrosion-resistant layer is a multi-element alloy layer including at least lead and tin.

[0016] In one embodiment, the positive electrode active material layer and / or the negative electrode active material layer uses a lead sulfate material modified by doping a graphene component in lead sulfate particles and in the molecular lattice of lead sulfate.

[0017] In one embodiment, the battery further comprises a positive output plate, a negative output plate, and a locking assembly.

[0018] The positive output plate is arranged at one end of the battery module exposed to the first opening and serves as the positive electrode of the battery; the negative output plate is arranged at one end of the battery module exposed to the second opening and serves as the negative electrode of the battery.

[0019] The locking assembly is used to lock and fix the positive output plate, the packaging frame of each battery monomer, and the negative output plate.

[0020] An energy storage device comprising the battery as claimed in any one of the above embodiments.

[0021] The above battery and energy storage device keep the charge cut-off voltage of each battery monomer less than the gas evolution voltage of its positive and negative electrodes, so that each battery monomer is in a high-efficiency charge and discharge state of more than 90% during the entire charging period, thereby improving problems such as battery thermal runaway, thermal deformation, and oxidation loss of the positive electrode current collector, and greatly improving the charge and discharge efficiency and service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a schematic view of the cross-sectional structure of a battery monomer in an embodiment of the present application.

[0023] Figure 2 for Figure 1 a cross-sectional structure schematic diagram of a battery cell packaging frame;

[0024] Figure 3 for a cross-sectional structure schematic diagram of a battery in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without using some or all of these specific details, and that the present application is not limited to the specific embodiments disclosed below.

[0026] In the description of the present application, 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", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0027] In addition, the terms "first", "second", "third" and the like are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0028] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0031] Please see Figure 1 , Figure 2 and Figure 3 As shown, an embodiment of the present invention provides a battery 100, which includes a plurality of battery cells 100, and the battery cells 100 are stacked sequentially along a preset direction to form a battery module.

[0032] Specifically, each battery cell 100 includes a bipolar plate 10, an encapsulation frame 21, a first separator 22, and a second separator 23. The encapsulation frame 21 has a receiving cavity 211 and a first opening 212 and a second opening 213 located on opposite sides of the encapsulation frame 21. The bipolar plate 10 is disposed within the receiving cavity 211 of the encapsulation frame 21. The first separator 22 is disposed at the first opening 212, and the second separator 23 is disposed at the second opening 213, thereby encapsulating the bipolar substrate 11 within the encapsulation frame 21.

[0033] In an embodiment of the present invention, the bipolar plate 10 includes a substrate 11, a positive current collector 12, a negative current collector 13, a positive active material layer 14, and a negative active material layer 15. The substrate 11 is disposed in a receiving cavity 211. The positive current collector 12 is stacked on the side of the substrate 11 facing the first opening 212. The negative current collector 13 is stacked on the side of the substrate 11 facing the second opening 213. The positive active material layer 14 is stacked on the side of the positive current collector 12 away from the substrate 11, and the negative active material layer 15 is stacked on the side of the negative current collector 13 away from the substrate 11.

[0034] In a specific embodiment, a conductive antioxidant layer is provided on the surface of the positive current collector 12. Thus, by providing a conductive antioxidant layer on the surface of the positive current collector 12, when oxygen is evolved on the surface of the positive current collector 12 during charging, the positive current collector 12 will not generate non-conductive PbO under the protection of the antioxidant layer. n The layer (i.e., a mixture of PbO and PbO2) is conductive, thus preventing the electrical conduction between the positive electrode active material layer 14 and the positive electrode current collector 12 from being blocked, which is beneficial to improving the battery's high-current charge and discharge capability and lifespan. Optionally, the positive electrode current collector 12 can be a lead foil layer.

[0035] In a specific embodiment, the antioxidant layer is a multi-element alloy layer comprising at least tin and bismuth. Thus, tin provides excellent conductivity and corrosion resistance, while bismuth provides excellent oxidation resistance, resulting in an antioxidant layer that possesses both strong oxidation resistance and good conductivity. This avoids the formation of non-conductive PbO on the surface of the positive electrode current collector 12. n On the one hand, the positive electrode active material layer 14 is kept electrically conductive with the positive electrode current collector 12 through the anti-oxidation layer. Optionally, the anti-oxidation layer can be formed on the surface of the positive electrode current collector 12 by electroplating.

[0036] In a specific embodiment, the negative electrode current collector 13 can be a copper foil layer. Thus, in this embodiment, a copper foil layer is used instead of traditional lead as the negative electrode current collector 13. Since the resistivity of copper foil is 16.73 ohms, while the resistivity of lead is 206.43 ohms, the conductivity of the negative electrode current collector 13 is greatly improved, which is beneficial for improving the battery's high-current charge and discharge capability. Furthermore, a corrosion-resistant layer resistant to electrolyte corrosion is provided on the surface of the negative electrode current collector 13. Optionally, this corrosion-resistant layer can be a multi-element alloy layer comprising at least lead and tin.

[0037] In a specific embodiment, the bipolar plate 10 further includes reinforcing ribs 16. The substrate 11 includes at least two sub-substrates 111 joined together, with each pair of adjacent sub-substrates 111 fixedly connected by reinforcing ribs 16. The positive current collector 12 and the positive active material layer 14 are stacked on the same side of each sub-substrate 111, while the negative current collector 13 and the negative active material layer 15 are stacked on the other side of each sub-substrate 111. Thus, the substrate 11 is formed by joining the sub-substrates 111 using reinforcing ribs 16, which improves the bending resistance of the substrate 11 and facilitates processing and transportation. Especially when the substrate 11 is large, processing and transporting a single large substrate 11 is difficult. However, in this embodiment, the large substrate 11 is formed by joining two or more smaller sub-substrates 111, thereby greatly reducing the difficulty of processing and transportation.

[0038] Furthermore, each reinforcing rib 16 is welded to the positive current collector 12 on two adjacent sub-substrates 111, and each reinforcing rib 16 is welded to the negative current collector 13 on two adjacent sub-substrates 111. In this way, on the one hand, the positive current collector 12 and the negative current collector 13 are electrically connected through the reinforcing ribs 16; on the other hand, the splicing of each sub-substrate 111 is achieved. It should be noted that the reinforcing ribs 16 are supported by a conductive material, such as copper.

[0039] Furthermore, one end of each reinforcing rib 16 extends out of the negative current collector 13 into the negative active material layer 15, thereby further improving the bending resistance of the bipolar plate 10. Of course, the other end of each reinforcing rib 16 can also extend out of the positive current collector 12 into the positive active material layer 14.

[0040] It should be noted that both ends of the reinforcing rib 16 extend into the negative electrode active material layer 15 and the positive electrode active material layer 14 respectively, which can enhance the bending resistance of the bipolar electrode plate 10, but it is inconvenient for clamping and transportation during the production process. Therefore, the reinforcing rib 16 is preferably extended into the negative electrode active material layer 15 or the positive electrode active material layer 14 only at one end. Specifically... Figure 1 In the embodiment shown, one end of each reinforcing rib 16 extends out of the negative current collector 13 into the negative active material layer 15, while the other end of each reinforcing rib 16 does not extend out of the positive current collector 12.

[0041] Please see Figure 3 As shown, in an embodiment of the present invention, the battery 200 further includes a positive output plate 41 and a negative output plate 42.

[0042] Since the individual battery cells 100 are stacked sequentially along a preset direction to form a battery module, one end of the battery module in that preset direction exposes a first opening 212, and the other end of the battery module in that preset direction exposes a second opening 213. Specifically... Figure 3 In the embodiment shown, the first opening 212 of the encapsulation frame 21 of the uppermost battery cell 100 of the battery module faces upward, meaning that the upper end of the battery module has the first opening 212 exposed. The second opening 213 of the encapsulation frame 21 of the lowermost battery cell 100 of the battery module faces upward, meaning that the lower end of the battery module has the second opening 213 exposed.

[0043] A positive electrode output plate 41 is disposed at the end of the battery module that exposes the first opening 212, serving as the positive electrode of the battery. A negative electrode output plate 42 is disposed at the end of the battery module that exposes the second opening 213, serving as the negative electrode of the battery.

[0044] In a specific embodiment, the battery 200 also includes a locking assembly (not shown in the figure), which is used to lock and fix the positive output plate 41, the encapsulation frame 21 of each battery cell 100 and the negative output plate 42 to form a whole.

[0045] Furthermore, the locking assembly includes a pull rod 31 and a locking member 32. One end of the pull rod 31 has a limiting portion 311. The pull rod 31 passes through the negative output plate 42, the encapsulation frame 21 of each battery cell 100, and the positive output plate 41. The locking member 32 is threadedly connected to the end of the pull rod 31 away from the limiting portion 311, thereby limiting the negative output plate 42, the encapsulation frame 21 of each battery cell 100, and the positive output plate 41 between the limiting portion 311 and the locking member 32. Optionally, the pull rod 31 can be a bolt, and the locking member 32 can be a nut.

[0046] It should be noted that the active materials of traditional lead-based batteries are mainly composed of lead powder and lead oxide powder. During charging, the lead powder in the positive electrode active material is transformed into lead oxide under oxidation, while the negative electrode is transformed into elemental lead powder under reduction conditions. During discharging, the active materials of both the positive and negative electrodes are gradually transformed into lead sulfate powder. When the proportion of non-conductive lead sulfate powder in the positive and negative active materials exceeds 50%, the current conduction function between lead powder or lead oxide powder is disrupted. Furthermore, after multiple charge-discharge cycles, some lead sulfate powder in the active materials of traditional lead-based batteries agglomerates into non-conductive clumps. Therefore, the utilization rate of active materials in lead-based batteries is generally less than 50%, resulting in generally poor specific capacity and specific power of lead-based batteries.

[0047] To address the shortcomings of traditional lead-based batteries, in embodiments of the present invention, the positive electrode active material layer 14 and / or the negative electrode active material layer 15 are modified lead sulfate materials by doping graphene into the lead sulfate particles and the lead sulfate molecular lattice. Thus, the modified lead sulfate material, due to the presence of fine graphite particles containing graphene in the lead sulfate particles and the lead sulfate molecular lattice, exhibits excellent conductivity. Therefore, when this modified lead sulfate material is used as the positive electrode active material layer 14 and / or the negative electrode active material layer 15, it can maintain good conductivity continuously during charging and discharging. Even when the lead sulfate content in the positive electrode active material layer 14 and / or the negative electrode active material layer 15 is 100%, it ensures excellent conductivity and high activity, thereby significantly improving the specific capacity and specific power of the lead-based battery. It also prevents the formation of non-conductive interfaces and agglomerates on the surface and inside the active material of the electrode plates, significantly extending the service life of the lead-based battery.

[0048] Furthermore, a high-speed stirring device is used to rapidly stir the recovered lead sulfate powder, diluted sulfuric acid solution, graphite powder containing nano-graphene, and several acid-resistant impact balls (such as zigzag balls). This allows the impact balls to deliver high-energy impacts to the lead sulfate molecules, causing cracks in the lead sulfate particles and lattice distortion. This allows the nano-graphite particles to more easily enter the cracks in the lead sulfate particles and the molecular lattice. Then, rapid cooling causes the dissolved lead sulfate to precipitate as fine crystals, thus obtaining the modified lead sulfate material.

[0049] It should be noted that under current standards, the standard charging cutoff voltage for a lead-based battery with an output voltage of 12V is 14.2V. Existing batteries are formed by stacking six individual cells, therefore the charging cutoff voltage for each individual cell is approximately 2.367V (i.e., 14.2V / 6).

[0050] However, the inventors of this application have creatively discovered that the charging efficiency of the battery cell 100 is greater than 90% before the charging voltage reaches 2.15V. When the charging voltage of the battery cell 100 reaches 2.15V, the battery capacity is already 90% charged. After the charging voltage of the battery cell 100 exceeds 2.15V, the charging efficiency drops sharply, and the charging loss causes the battery temperature to rise rapidly. At the same time, the voltage of the positive current collector 12 and the negative current collector 13 approaches the gas evolution voltage (around 2.3V), causing a large amount of oxygen to be evolved from the positive current collector, resulting in oxidation loss. Therefore, the main cause of thermal runaway, thermal deformation, and oxidation loss of the positive current collector in lead-based batteries is the low-efficiency charging in the later stages (i.e., when the voltage of the positive and negative current collectors of each battery cell is near or exceeds the gas evolution voltage).

[0051] To address the aforementioned disadvantages caused by the higher charging voltage of each battery cell 100 during the later stages of charging, in one embodiment, the charging cut-off voltage of each battery cell 100 is lower than the gas evolution voltage of its positive and negative electrodes. This gas evolution voltage is the voltage at which a large amount of gas is evolved at the positive current collector 12 and negative current collector 13 of the battery cell 100.

[0052] Please see Figure 3As shown, in a specific embodiment, the output voltage of battery 200 is 12V. Battery 200 comprises seven individual battery cells 100, meaning the seven individual battery cells 100 are stacked along a predetermined direction to form a battery module. Thus, while maintaining a standard output voltage of 12V and a charging cutoff voltage of 14.2V, the charging cutoff voltage of each individual battery cell 100 is 2.03V (14.2V ÷ 7), which is less than 2.15V (ensuring it is far less than the gas evolution voltage of 2.3V). This ensures that each individual battery cell 100 is in a highly efficient charge / discharge state of over 90% throughout the entire charging period, thereby improving problems such as battery thermal runaway, thermal deformation, and oxidation loss of the positive electrode current collector 12, and increasing battery lifespan.

[0053] Based on the aforementioned battery, the present invention also provides an energy storage device, which includes the battery 200 as described in any of the above embodiments. Specifically, this energy storage device can be applied in scenarios requiring energy storage and discharging, such as energy storage cabinets, electric vehicles, ships, spacecraft, and submarines, and is not limited thereto.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A battery, characterized in that, The battery includes multiple battery cells (100), and each of the battery cells (100) is stacked sequentially along a preset direction to form a battery module; The charging cutoff voltage of each of the battery cells (100) is less than the gas evolution voltage of its positive and negative electrodes.

2. The battery according to claim 1, characterized in that, The battery has an output voltage of 12V and comprises 7 battery cells (100).

3. The battery according to claim 1, characterized in that, Each of the battery cells (100) includes an encapsulation frame (21), a first separator (22), a second separator (23), and a bipolar plate (10); The encapsulation frame (21) has a receiving cavity (211) and a first opening (212) and a second opening (213) located on opposite sides of the encapsulation frame (21). The bipolar plate (10) is disposed in the receiving cavity (211). The first isolation film (22) is disposed at the first opening (212), and the second isolation film (23) is disposed at the second opening (213).

4. The battery according to claim 3, characterized in that, The bipolar plate (10) includes a substrate (11), a positive current collector (12), a negative current collector (13), a positive active material layer (14), and a negative active material layer (15); The positive current collector (12) is stacked on the side of the substrate (11) facing the first opening (212), and the negative current collector (13) is stacked on the side of the substrate (11) facing the second opening (213). The positive electrode active material layer (14) is stacked on the side of the negative electrode current collector (13) away from the substrate (11), and the negative electrode active material layer (15) is stacked on the side of the negative electrode current collector (13) away from the substrate (11).

5. The battery according to claim 4, characterized in that, The surface of the positive current collector (12) is provided with an antioxidant layer that can conduct electricity.

6. The battery according to claim 5, characterized in that, The antioxidant layer is a multi-element alloy layer comprising at least tin and bismuth.

7. The battery according to claim 5, characterized in that, The negative current collector (13) is a copper foil layer.

8. The battery according to claim 4, characterized in that, The positive electrode active material layer (14) and / or the negative electrode active material layer (15) are made of lead sulfate material modified by doping graphene components into lead sulfate particles and into the molecular lattice of lead sulfate.

9. The battery according to claim 3, characterized in that, The battery also includes a positive output plate (41), a negative output plate (42), and a locking assembly; The positive electrode output plate (41) is disposed at one end of the battery module that exposes the first opening (212) and serves as the positive electrode of the battery; the negative electrode output plate (42) is disposed at one end of the battery module that exposes the second opening (213) and serves as the negative electrode of the battery. The locking assembly is used to lock and fix the positive output plate (41), the encapsulation frame (21) of each of the battery cells (100) and the negative output plate (42).

10. An energy storage device, characterized in that, Includes the battery (200) as described in any one of claims 1 to 9.

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