Energy storage device

Abstract

An embodiment of the present invention discloses an energy storage device. The energy storage device includes: a housing and an energy conversion element, the housing including a first half housing and a second half housing; both the first half housing and the second half housing include a recessed structure and an edge portion, the edge portion is disposed around the mouth of the recessed structure and is connected to the mouth, the recessed structure of the first half housing and the recessed structure of the second half housing together enclose a cavity, the energy conversion element is disposed in the cavity, the edge portion of the first half housing is hermetically connected to the edge portion of the second half housing to form a sealing edge, a part of the sealing edge is bent toward a first side of the housing, and another part is bent toward a second side of the housing opposite to the first side.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conversion, and more specifically, to an energy storage device. Background Art

[0002] Energy storage devices, such as soft-pack batteries, usually include a winding core and two half-shells that are buckled together. The winding core is assembled into a space surrounded by two half-shells. The two pole ears of the winding core extend outward from the edges of the two half-shells. The two half-shells are insulated. For example, the half-shells are aluminum-plastic films. The pole ears are also insulated from the two half-shells. The edges of the two half-shells are connected together by hot pressing. The plastic layer on the surface of the aluminum-plastic film is a thermoplastic material. When heated to a set temperature, the plastic layer on the aluminum-plastic film becomes sticky. Under the action of external pressure, the two edges are bonded together, and the pole ears are bonded to the two edges.

[0003] Normally, the edges that are bonded together extend outward, which makes the energy storage device large and not conducive to assembly to other equipment. In some schemes, the edges that are bonded together are bent to one side and fit onto the side wall of the shell. In traditional soft-pack batteries, the edge seals of the packaging film are all bent to one side, but in this scheme, since the edges are annular edge seals, if they are bent to one side, the shell will usually wrinkle to form an elastic deformation structure, so the bent part is prone to dimensional rebound, affecting dimensional consistency and assembly use. The wrinkles will also take up a large space, thereby limiting the energy space utilization of the battery, and the battery energy density is low. In addition, if the structural shell is modified to a packaging material with greater hardness and thickness, such as stainless steel foil, its strength is too high to form wrinkles well, and structural damage may occur during the wrinkle formation process, thereby destroying the sealing performance.

[0004] Therefore, it is necessary to provide a new technical solution to solve at least one of the above technical problems. Summary of the invention

[0005] An object of the present invention is to provide a new technical solution for an energy storage device.

[0006] According to a first aspect of the present invention, an energy storage device is provided. The energy storage device comprises: a shell and an energy conversion element, the shell comprising a first half shell and a second half shell; the first half shell and the second half shell both comprise a recessed structure and an edge portion, the edge portion is arranged around the mouth of the recessed structure and connected to the mouth, the recessed structure of the first half shell and the recessed structure of the second half shell together form a cavity, the energy conversion element is arranged in the cavity, the edge portion of the first half shell is sealed and connected to the edge portion of the second half shell to form a sealing edge, a portion of the sealing edge is bent toward the first side of the shell, and another portion is bent toward the second side of the shell in a direction opposite to the first side.

[0007] Optionally, the sealing edge is attached to the outer surface of the shell.

[0008] Optionally, the conducting portion is provided on the recessed structure, and the conducting portion is connected to the energy conversion element.

[0009] Optionally, the sealing edge is bonded to the outer surface of the housing by glue.

[0010] Optionally, the shell is a rectangular parallelepiped, at least one of the four corners of the sealing edge is bent toward the first side, and a portion of the sealing edge other than the corner is bent toward the second side.

[0011] Optionally, at least two locations of the sealing edge are bent toward the first side, and a portion of the sealing edge other than the at least two locations is bent toward the second side.

[0012] Optionally, the at least two locations are evenly distributed along the circumference of the sealing edge.

[0013] Optionally, the edge portion of the first half shell and the edge portion of the second half shell are connected by thermoplastic material.

[0014] Optionally, the first half shell and the second half shell have the same height, and the width of the sealing edge is equal to the height of the first half shell.

[0015] Optionally, at least one of the first half shell and the second half shell includes a metal layer and two thermoplastic material layers, the metal layer is located between the two thermoplastic material layers, the two thermoplastic material layers form a hollow structure at corresponding positions to expose the metal layer, and the metal layer is connected to the energy conversion element.

[0016] According to an embodiment of the present disclosure, a portion of the sealing edge is bent toward the first side, and another portion is bent toward the second side, rather than being bent toward one side as a whole. In this way, the rebound forces of the bending on both sides can offset each other, thereby preventing the sealing edge from detaching from the side wall of the housing.

[0017] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0019] Figure 1 is an exploded view of a soft-pack battery during assembly according to an embodiment of the present disclosure.

[0020] Figure 2 is an exploded view of a half shell according to an embodiment of the present disclosure.

[0021] Figure 3 is a cross-sectional view of a soft-pack battery without vacuuming according to an embodiment of the present disclosure.

[0022] Figure 4 is a cross-sectional view of a vacuum-evacuated soft-pack battery according to an embodiment of the present disclosure.

[0023] Figure 5 is a three-dimensional diagram of another soft-pack battery according to an embodiment of the present disclosure

[0024] Figure 6 is a cross-sectional view of a soft-pack battery according to an embodiment of the present disclosure.

[0025] Figure 7 is a stereoscopic diagram of another soft-pack battery according to an embodiment of the present disclosure.

[0026] Figure 8 is a side view of yet another soft-pack battery according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0028] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0029] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0031] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] According to one embodiment of the present disclosure, an energy storage device is provided. Figure 1-Figure 4 As shown, the energy storage device may be, but is not limited to, a capacitor, a battery, etc. The battery is a primary battery or a secondary battery. The following is an example of a lithium-ion battery. For example, the lithium-ion battery is a soft-pack battery or a button battery.

[0033] The energy storage device includes a shell and an energy conversion element. The energy conversion element is used for conversion between chemical energy and electrical energy. For example, the energy conversion element includes a winding core 11. The winding core 11 is a winding structure or a laminated structure. The winding structure is that the entire electrode sheet (for example, the electrode sheet includes a positive electrode sheet, a negative electrode sheet and a separator located between the positive electrode sheet and the negative electrode sheet) is wound into a spiral structure. The laminated structure is that the electrode sheet is divided into multiple sheets. Multiple sheets are stacked together.

[0034] The energy conversion element is a block structure. For example, a rectangular structure, a cylindrical structure, an elliptical cylinder structure, etc. An electrode terminal is attached to at least one surface of the energy conversion element. The electrode terminal is connected to the electrode of the energy conversion element. For example, the electrode terminal is a pole ear 111. The pole ear 111 is a nickel sheet, etc. Alternatively, the electrode terminal is an empty foil area of ​​the pole piece of the winding core 11. The empty foil area is the part of the pole piece that is not covered with the electrode active material.

[0035] The shell includes a first half shell 12 and a second half shell 13. The interior of the shell forms a closed cavity. The first half shell 12 and the second half shell 13 each include a recessed structure 14 and an edge portion 155. The edge portion 155 is arranged around the mouth of the recessed structure 14 and connected to the mouth. The recessed structure 14 of the first half shell 12 and the recessed structure 14 of the second half shell 13 together form a cavity.

[0036] The energy conversion element is disposed in the cavity. The edge portion 155 of the first half shell 12 is sealed 15 with the edge portion 155 of the second half shell 13 to form a sealed edge 15. For example, the sealed connection 15 is formed by bonding, welding, hot-melt connection, etc.

[0037] A portion of the sealing edge 15 is bent toward a first side 15a of the shell, and another portion is bent toward a second side 15b of the shell in a direction opposite to the first side 15a. For example, the first side 15a is a side close to the side wall of the first half shell 12; the second side 15b is a side close to the side wall of the second half shell.

[0038] like Figure 4 and Figure 5 As shown, the housing is in a rectangular parallelepiped structure, a cylindrical structure, an elliptical cylindrical structure, etc. Those skilled in the art can make configurations according to actual needs.

[0039] In the disclosed embodiment, a portion of the sealing edge 15 is bent toward the first side 15a, and another portion is bent toward the second side 15b, rather than being bent toward one side as a whole. In this way, the rebound forces of the bending on both sides can offset each other, thereby preventing the sealing edge 15 from detaching from the side wall of the housing.

[0040] In addition, compared with the bending on one side, the bending on both sides makes the circumferential distance of the sealing edge 15 larger, and a part of the sealing edge 15 overlaps. In this way, after bending, the sealing edge 15 can be evenly attached to the outer surface of the shell without forming wrinkles. The surface of the energy storage device is flat.

[0041] In other examples, the sealing edge 15 has a set distance from the outer surface of the housing after being bent, rather than being in contact with the outer surface.

[0042] In an example, Figure 1 As shown, the conductive part is provided on the recessed structure 14, and the conductive part is connected to the energy conversion element. For example, the conductive part is a metal sheet 115, and the energy conversion element is connected to an external device through the metal sheet 115. The conductive part serves as an electrode of the energy storage device.

[0043] Of course, the conductive portion may also be an exposed metal layer, as described below.

[0044] In one example, the sealing edge 15 is bonded to the outer surface of the housing by glue. In this way, the sealing edge 15 can be more firmly fixed to the outer surface of the housing.

[0045] In an example, Figure 5As shown, the housing is a rectangular parallelepiped. At least one of the four corners of the sealing edge 15 is bent toward the first side 15a. The portion of the sealing edge 15 other than the corner is bent toward the second side 15b.

[0046] For example, the four corners are all bent toward the first side 15a. In this example, the bending direction of the corners is opposite to the bending direction of other parts. In this way, the circumferential distance of the sealing edge 15 is larger, and the overlapping area is larger. The sealing edge 15 fits more closely on the outer surface of the shell.

[0047] In one example, at least two portions of the sealing edge 15 are bent toward the first side 15a, and portions of the sealing edge 15 other than the at least two portions are bent toward the second side 15b. Figure 7-Figure 8 As shown, the housing is cylindrical in shape. Two places of the sealing edge 15 are bent toward the first side 15a, and the two places are arranged opposite to each other. This makes the bending of the sealing edge 15 more stable.

[0048] For example, the at least two locations are evenly distributed along the circumference of the sealing edge 15. In this way, the sealing edge 15 is subjected to more balanced forces at various locations, and has a higher ability to maintain bending.

[0049] In one example, the first half shell 12 and the second half shell 13 have the same height. Figure 5 In this way, after being bent, the outer edge of the sealing edge 15 can be flush with the upper and lower surfaces of the housing, which makes the appearance of the housing more regular.

[0050] According to another embodiment of the present disclosure, a method for manufacturing an energy storage device is provided. The manufacturing method comprises:

[0051] Placing the energy conversion element into the cavity, wherein the electrode terminal is opposite to the conductive portion of the shell;

[0052] The cavity is evacuated, and the conductive part is pressed against the electrode terminal by atmospheric pressure. When evacuating, the air pressure in the cavity is less than the atmospheric pressure. Under the action of atmospheric pressure, the shell is partially deformed. The conductive part gradually approaches the electrode terminal, and finally contacts the electrode terminal and fits tightly together. When charging and discharging, the winding core 11 is connected to the external circuit through the electrode terminal and the conductive part.

[0053] In the disclosed embodiment, the cavity is evacuated and atmospheric pressure is used to make the conductive part of the shell contact the electrode terminal, as opposed to welding the two together. In this way, the energy conversion element will not be affected by high temperature, thereby maintaining good energy conversion performance.

[0054] In addition, when gas appears in the energy storage device, for example, when the internal air pressure is greater than the atmospheric pressure, the shell gradually expands due to the internal air pressure. The conductive part gradually moves away from the energy conversion element until it is separated from the electrode terminal. In this way, the conductive part and the electrode terminal form a circuit break, and charging and discharging stop. In this way, the explosion of the energy storage device can be effectively avoided.

[0055] Figure 1 : is an exploded view of a soft-pack battery during assembly according to an embodiment of the present disclosure. In this example, the shell includes a first half shell 12 and a second half shell 13 that are sealed together. The first half shell 12 and the second half shell 13 each include a recessed structure 14 and an edge portion 155 formed by extending outward from the edge of the recessed structure 14. The edge portion 155 is configured for sealed connection, the recessed structure 14 constitutes at least a portion of the cavity, and the conductive portion is provided on the recessed structure 14. In one example, during assembly, the two recessed structures 14 are opposite. The edge portions 155 of the first half shell 12 and the second half shell 13 are fitted together to form a sealed edge. For example, a thermoplastic material is provided on the edge portion 155, and the edge portions 155 of the first half shell 12 and the second half shell 13 are connected together by hot pressing.

[0056] For example, the first half shell 12 and the second half shell 13 are both metal plastic films, such as aluminum plastic films, steel plastic films, etc. The plastic material on the metal plastic film can be formed into a sealed connection by hot pressing.

[0057] Alternatively, the first half shell 12 and the second half shell 13 are made of plastic, such as polyetherketone (PEK), polyetheretherketone (PEEK), polypropylene (PP), etc. The above materials are thermoplastic materials and can be connected by hot pressing.

[0058] In one example, before the cavity is evacuated, the process further includes: injecting electrolyte into the cavity. For example, the cavity is in the shape of a rectangular parallelepiped, and after the energy conversion element is placed in the cavity, the edge portions 155 on three sides (e.g., three short sides 155b) of the rectangular parallelepiped are sealed. The edge portion 155 on another side (e.g., long side 155a) forms an injection port 151. The injection port 151 is configured to be used for injecting electrolyte.

[0059] For example, the short sides 155b of the edge portions 155 of the two half shells are first sealed. The long sides 155a are not completely sealed to form the injection port 151. For example, the edges of the long sides 15a are connected to form a bag. The bag is used to contain the gas generated during activation. The electrolyte is a carrier for ion transmission. For example, lithium ions migrate in the electrolyte to perform charging and discharging.

[0060] After the electrolyte is injected, the shell is sealed for the first time. For example, the electrolyte is injected into the cavity at the injection port 151. After the injection is completed, the first sealing is performed to close the injection port 151.

[0061] The conductive part is pressed against the electrode terminal by mechanical pressure, and the formation process is performed. For example, pressure is applied from the outside of the conductive part toward the electrode terminal to make the two contact. While maintaining the contact, the winding core 11 is charged and discharged to perform the formation process on the energy storage device.

[0062] In this example, since the conductive portion and the electrode terminal are opposite to each other, the conductive portion and the electrode terminal can be connected to each other only by applying mechanical pressure.

[0063] Furthermore, when the winding core 11 is defective, the conducting portion and the electrode terminal can be separated at any time, so that the winding core 11 can be easily replaced.

[0064] In one example, after the cavity is evacuated, the shell is also sealed for a second time. For example, after the formation process is completed, the first seal is opened, for example, the first seal is cut on the side close to the winding core 11 to form an opening 152. Vacuum is evacuated at the opening 152. At this time, the gas in the cavity and the excess electrolyte will be discharged from the opening 152. Due to the effect of atmospheric pressure, the conductive part and the electrode terminal are pressed together to form contact.

[0065] After the vacuuming is completed, a second sealing is performed on the long side 155a to close the shell, thereby finally forming a complete energy storage device.

[0066] In an example, Figure 3-Figure 4 As shown, the cavity is cylindrical. The energy conversion element is cylindrical. Electrode terminals are respectively arranged on the two end faces of the energy conversion element. Conductive parts are respectively arranged on the parts of the shell corresponding to the two end faces of the cavity.

[0067] For example, the bottom of the first half shell 12 and the bottom of the second half shell 13 are both provided with a conducting part. The electrode terminals correspond to the conducting parts one by one. In this example, the two conducting parts are arranged opposite to each other, which makes it easy to connect the energy storage device with external equipment.

[0068] In an example, Figure 3-Figure 4 As shown, at least one of the first half shell and the second half shell includes a metal layer and two thermoplastic material layers. The metal layer is located between the two thermoplastic material layers. The two thermoplastic material layers form a hollow structure at corresponding positions to expose the metal layer. The metal layer is connected to the energy conversion element. A window structure 121 is formed on the thermoplastic material layer, and the portion of the metal layer located at the window structure 121 is the conductive part. For example, the shell has a multi-layer composite structure. The material of the thermoplastic material layer is PP, PEEK, PEK, etc. Thermoplastic material layers are provided on the upper and lower surfaces of the metal layer. The window structure 121 is formed at a set position of the thermoplastic material layer by etching and scraping to expose the conductive part in the window structure 121. In this way, the conductive part is directly formed on the shell, which makes it easy to set the conductive part.

[0069] In an example, Figure 2-Figure 4 As shown, the window structure 121 is a through hole. The conductive part is a metal sheet 115, for example, the metal sheet 115 is circular, rectangular, elliptical, semicircular, etc. A thermoplastic material ring, such as a plastic ring 116, is arranged at the edge of the metal sheet 115. When hot pressing is performed, the thermoplastic material ring melts and acquires viscosity. The thermoplastic material ring is bonded to the edge of the through hole, so that the metal sheet 115 closes the through hole. The metal sheet 115 serves as a conductive part.

[0070] In an example, Figure 6 As shown, a stem 112 is provided inside the energy conversion element. The end of the stem 112 is opposite to the electrode terminal. For example, the stem 112 is an insulating material, such as plastic, ceramic, glass, etc. The shape of the stem 112 is a cylinder, a square column, an elliptical column, a polygonal column, etc.

[0071] For example, the winding core 11 is wound outside the core column 112. Electrode terminals are arranged at both ends of the winding core 11 in the axial direction. The two electrode terminals are respectively against the two ends of the core column 112. When vacuuming, the core column 112 can squeeze the electrode terminals together with the conductive part, so that the electrode terminals and the conductive part can have good contact.

[0072] The core column 112 can also play a supporting role. The core column 112 makes it difficult for the shell to be deformed due to external force, thereby improving the structural strength of the energy storage device.

[0073] In other examples, the winding core 11 is a laminated structure. The core column 112 is perpendicular to the surface of each layer. A core column 112 that penetrates each layer is arranged in the middle of the winding core 11. The core column 112 can also play a role in supporting the electrode terminal.

[0074] In an example, Figure 6As shown, a bump 118 is provided at a contacting portion of the conductive portion and / or the electrode terminal. For example, a bump 118 is provided on the electrode terminal. A plurality of bumps 118 are distributed in a matrix. When vacuuming, the bump 118 first contacts the conductive portion. Due to the effect of atmospheric pressure, a pit is formed in the conductive portion. The bump 118 cooperates with the pit to effectively prevent the electrode terminal from moving relative to the conductive portion.

[0075] In addition, when the conductive portion and the electrode terminal are completely pressed together, the bumps 118 can increase the contact area between the two, and the conductive portion and the electrode terminal form contact in space, rather than just in a plane, which makes the electrical connection between the two more stable.

[0076] In an example, Figure 1 As shown, a metal with an atomic number higher than nickel in the periodic table or an alloy of the above metals, such as a sheet made of gold, silver, etc., is provided between the electrode terminal and the conductive part. By providing an intermediate metal layer 119, the connection between the electrode terminal and the conductive part is more secure, and the conductive effect is more significant; or

[0077] The electrode terminal is a metal with an atomic number higher than nickel in the periodic table or an alloy of the above metals, and the types of metals are as described above. In this example, the tab 111 or the electrode sheet is a metal higher than nickel, which has low resistance, low heat generation during charging and discharging, and is safe and reliable; or

[0078] The electrode terminal is a composite structure of multiple layers of metal, one of which is a metal with an atomic number higher than nickel in the periodic table or an alloy of the above metals. For example, the tab 111 or the electrode sheet is a composite of at least two of the above metal layers. In this way, the conductivity and structural strength of the electrode terminal are higher; or

[0079] The electrode terminal is doped with a metal with an atomic number higher than nickel in the periodic table. This material has a good conduction effect.

[0080] In an example, Figure 1 As shown, an insulating component 117 is provided between the electrode terminal and the energy conversion element. For example, the insulating component 117 is made of plastic, rubber, silicone, etc. The insulating component 117 can prevent the electrode terminal from contacting the winding core 11, thereby avoiding a short circuit.

[0081] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. An energy storage device, characterized in that, it includes: a housing and an energy conversion element, the housing includes a first half housing and a second half housing; both the first half housing and the second half housing include a recessed structure and an edge portion, the edge portion is disposed around the mouth of the recessed structure and is connected to the mouth, the recessed structure of the first half housing and the recessed structure of the second half housing together enclose a cavity, the energy conversion element is disposed in the cavity, the edge portion of the first half housing and the edge portion of the second half housing are hermetically connected to form a sealing edge, a part of the sealing edge is bent toward the first side of the housing, and another part is bent toward the second side of the housing opposite to the first side.

2. The energy storage device according to claim 1, characterized in that, the sealing edge is attached to the outer surface of the housing.

3. The energy storage device according to claim 1, characterized in that, a conduction portion is provided on the recessed structure, and the conduction portion is connected to the energy conversion element.

4. The energy storage device according to claim 1, characterized in that: the sealing edge is adhesively bonded to the outer surface of the housing by glue.

5. The energy storage device according to claim 1, characterized in that: the housing is a cuboid, at least one of the four corners of the sealing edge is bent toward the first side, and the portion of the sealing edge other than the corner is bent toward the second side.

6. The energy storage device according to claim 1, characterized in that: at least two portions of the sealing edge are bent toward the first side, and the portion of the sealing edge other than the at least two bends is bent toward the second side.

7. The energy storage device according to claim 6, characterized in that: the at least two bends are evenly distributed along the circumference of the sealing edge.

8. The energy storage device according to claim 1, characterized in that: the edge portion of the first half housing and the edge portion of the second half housing are connected by a thermoplastic material.

9. The energy storage device according to claim 1, characterized in that: the first half housing and the second half housing have the same height, and the width of the sealing edge is equal to the height of the first half housing.

10. The energy storage device according to claim 1, characterized in that: at least one of the first half housing and the second half housing includes a metal layer and two thermoplastic material layers, the metal layer is located between the two thermoplastic material layers, and the two thermoplastic material layers form a hollow structure at corresponding positions to expose the metal layer, and the metal layer is connected to the energy conversion element.

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