Electrode assembly, battery cell, and electrochemical device

Abstract

The utility model discloses an electrode assembly, electric core and electrochemical device, this electrode assembly includes the first pole piece, second pole piece and isolation membrane of laminated setting, and isolation membrane is located between the first pole piece and second pole piece, the polarity of first pole piece and second pole piece is opposite, and the electrode assembly still includes first lug bundle and fastener, and first lug bundle includes a plurality of first lug, and a plurality of first lug laminated setting forms first lug bundle, and first lug connects the first pole piece, and the end of first lug connecting the first pole piece is arranged along the first direction, and the first direction is the thickness direction of electrode assembly, and fastener is installed in first lug bundle to fix first lug bundle, the electrode assembly that the application proposes aims at improving the connection stability of a plurality of lug in electrode assembly.

Description

Technical Field

[0001] This application relates to the field of electrochemical energy storage, and in particular to an electrode assembly, a battery cell, and an electrochemical device. Background Technology

[0002] Multi-tab lithium-ion batteries are a type of lithium-ion battery design that optimizes battery performance by increasing the number of tabs. They are mainly used in consumer electronics, electric vehicles, and other fields. Their high current carrying capacity and fast charge and discharge characteristics make them suitable for scenarios with high performance requirements.

[0003] Existing multi-tab lithium-ion batteries mainly use ultrasonic welding to connect multiple tabs into one unit. However, the welding quality of ultrasonic welding is affected by fluctuations in welding parameters, and problems such as incomplete welding or over-welding are prone to occur, affecting the connection stability between multiple tabs. Utility Model Content

[0004] The main objective of this application is to provide an electrode assembly designed to improve the connection stability of multiple tabs within the electrode assembly.

[0005] To achieve the above objectives, this application proposes an electrode assembly comprising a first electrode, a second electrode, and a separating membrane stacked together, wherein the separating membrane is located between the first electrode and the second electrode; the first electrode and the second electrode have opposite polarities; the electrode assembly further comprises:

[0006] The first electrode bundle includes a plurality of first electrodes, which are stacked to form the first electrode bundle. The first electrodes are connected to the first electrode plate, and the ends of the first electrodes connected to the first electrode plate are arranged along a first direction, which is the thickness direction of the electrode assembly.

[0007] Fasteners are installed on the first electrode bundle to secure the first electrode bundle.

[0008] In some embodiments, the fastener is a ring-shaped structure, and the fastener is arranged around the outer periphery of the first electrode bundle.

[0009] In some embodiments, the fastener includes a first portion and a second portion, the first portion and the second portion being detachably connected to the outer periphery of the first tab bundle.

[0010] In some embodiments, the inner height of the fastener is the sum of the thicknesses of the plurality of first tabs, and the inner width of the fastener is the width of the first tabs.

[0011] In some embodiments, the first electrode bundle is provided with electrode tab adhesive near the first electrode sheet, and the distance between the fastener and the electrode tab adhesive is L1, wherein L1 satisfies: L1≥5mm.

[0012] In some embodiments, the distance between the fastener and the side of the first electrode bundle away from the first electrode plate is L2, wherein L2 satisfies: L2≥5mm.

[0013] In some embodiments, the fastener is made of a conductive material.

[0014] In some embodiments, a second electrode bundle is also included, the second electrode bundle including a plurality of second electrodes, the plurality of second electrodes being stacked to form the second electrode bundle, the second electrodes being connected to the second electrode plate, and the ends of the second electrodes connected to the second electrode plate being arranged along the first direction;

[0015] The number of fasteners is at least one, and the fasteners are respectively connected to the first electrode bundle and / or the second electrode bundle to fix the first electrode bundle and / or the second electrode bundle.

[0016] This application also proposes a battery cell including the electrode assembly described above.

[0017] This application also proposes an electrochemical device comprising a battery cell as described above.

[0018] The electrode assembly in this application includes a first electrode sheet, a second electrode sheet, a separator membrane disposed between the first and second electrode sheets, a first electrode tab bundle, and fasteners. The first electrode tab bundle includes multiple stacked first electrode tabs, one end of which is connected to the first electrode sheet. The multiple first electrode tabs are arranged along the thickness direction of the electrode assembly. Fasteners are installed on the multiple first electrode tabs to gather them together to form the first electrode tab bundle, preventing the multiple first electrode tabs from scattering and thus affecting the performance and lifespan of the electrode assembly. The fasteners replace traditional welding connections, avoiding the degradation of the first electrode tab material performance caused by the heat-affected zone of welding, eliminating the risk of welding defects such as incomplete welding / over-welding, making the connection of the multiple first electrode tabs more stable, and improving the safety and service life of the electrode assembly. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an electrode assembly according to an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of the structure of an electrode assembly according to another embodiment of this application.

[0021] Reference numerals: 100, Electrode assembly; 120, First electrode bundle; 121, First electrode tab; 130, Fastener; 140, Electrode adhesive; 150, Second electrode bundle. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. The embodiments of this application may omit unnecessary detailed descriptions. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0023] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0024] Throughout this specification, references to “implementation,” “partial implementation,” “one implementation,” “another implementation,” “specific method,” or “partial method” mean that at least one implementation or embodiment in this application includes the specific features, structures, materials, or characteristics described in that implementation or embodiment.

[0025] In this application, numerical ranges are involved. Unless otherwise specified, the numerical ranges mentioned above are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form a range not explicitly stated.

[0026] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments should not be construed as limiting the present application, and that changes, substitutions and modifications can be made to the embodiments without departing from the spirit, principles and scope of the present application.

[0027] Multi-tab lithium-ion batteries are a type of lithium-ion battery design that optimizes battery performance by increasing the number of tabs. They are mainly used in consumer electronics, electric vehicles, and other fields. Their high current carrying capacity and fast charge and discharge characteristics make them suitable for scenarios with high performance requirements.

[0028] Existing multi-tab lithium-ion batteries mainly use ultrasonic welding to connect multiple tabs into one unit. However, the welding quality of ultrasonic welding is affected by fluctuations in welding parameters, and problems such as incomplete welding or over-welding are prone to occur, affecting the connection stability between multiple tabs.

[0029] The main objective of this application is to provide an electrode assembly designed to improve the connection stability of multiple tabs within the electrode assembly.

[0030] To achieve the above objectives, this application proposes an electrode assembly 100, with reference to... Figure 1 , Figure 1 This is a schematic diagram of the structure of an electrode assembly 100 according to an embodiment of this application. The electrode assembly 100 includes a first electrode, a second electrode, and a separator film stacked together, with the separator film located between the first and second electrode. The first and second electrode have opposite polarities. The electrode assembly 100 also includes a first electrode tab bundle 120 and a fastener 130. The first electrode tab bundle 120 includes a plurality of first electrode tabs 121, which are stacked to form the first electrode tab bundle 120. The first electrode tabs 121 are connected to the first electrode, and the ends of the first electrode tabs 121 connected to the first electrode are arranged along a first direction, which is the thickness direction of the electrode assembly 100. The fastener 130 is installed on the first electrode tab bundle 120 to fix the first electrode tab bundle 120.

[0031] In this embodiment, the stacked first electrode, second electrode, and separator are the most basic components of the battery, serving as the unit for storing and releasing electrical energy. The electrode includes a current collector and an active material layer disposed on at least one side of the current collector. The current collector can be a metal foil or a composite current collector. Depending on the polarity, the metal foil can be aluminum foil or copper foil. The composite current collector can include a metal foil substrate and a conductive layer disposed on at least one side of the metal foil substrate. Depending on the polarity, the metal foil substrate can be an aluminum foil substrate or a copper foil substrate. The conductive layer can be carbon, carbon black, graphite, expanded graphite, or other carbon materials.

[0032] The active material layer may include active materials, binders, and conductive agents. The active materials may be materials such as lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, NMC, NCA, or other materials that can be used as active materials. The binders may be materials such as polyvinylidene fluoride (PVDF), poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), polytetrafluoroethylene (PTFE), or other materials that can be used as battery binders. The conductive agents may be materials such as carbon, carbon black, graphite, expanded graphite, graphene, or other materials that can be used as battery conductive agents.

[0033] The separator separates the negative and positive electrodes and provides a pathway for lithium-ion migration. The use of the separator is not particularly restricted, as long as it is a commonly used separator in lithium-ion secondary batteries. In particular, separators with low resistance to electrolyte ion movement and excellent electrolyte permeability are preferred. Specifically, porous polymer membranes can be used, such as porous polymer membranes formed from polyolefin-based polymers (e.g., ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, ethylene / methacrylate copolymers, etc.) or laminated structures with two or more layers.

[0034] Tabs are crucial connecting components in a battery, enabling current conduction between the internal cells (positive and negative electrodes) and the external circuitry. In a multi-tab design, multiple tabs are welded onto each terminal (positive or negative). These tabs are then combined and connected to the battery's terminals via a current collector. This group of tabs connected in parallel is called a tab bundle. By shortening the current path through multi-tab design, the battery's internal resistance is fundamentally reduced, and the power and safety of the battery assembly are improved.

[0035] Fastener 130 is a component used to fix multiple first tabs 121 in the first tab bundle 120. By physically fixing the multiple first tabs 121 in the first tab bundle 120, welding defects such as incomplete welds / over-welds that occur during ultrasonic welding are avoided, making the connection of the multiple first tabs 121 more stable. The fastener 130 can be ring-shaped, with channels inside the ring structure fitting around the outer periphery of the first tab bundle 120 to prevent the multiple first tabs 121 from scattering. Alternatively, the fastener 130 can be U-shaped, possessing a certain degree of elasticity, and its deformation on both sides clamps the opposite surfaces of the first tab bundle 120 to prevent the multiple first tabs 121 from scattering. The fastener 130 can also be a serpentine winding structure, where an installation tool bends and winds the fastener 130 around the outer periphery of the first tab bundle 120, thereby preventing the multiple first tabs 121 from scattering and improving battery performance, safety, and lifespan. Fastener 130 is made of a conductive material, such as metals like copper, silver, and nickel, or non-metallic conductive materials like graphite. It is preferably made of a low-resistance material, such as copper or graphite, so as not to affect the conductivity of the first pole ear bundle 120.

[0036] The electrode assembly 100 in this application includes a first electrode sheet, a second electrode sheet, a separator membrane disposed between the first and second electrode sheets, a first electrode tab bundle 120, and fasteners 130. The first electrode tab bundle 120 includes multiple stacked first electrode tabs 121, one end of which is connected to the first electrode sheet. The multiple first electrode tabs 121 are arranged along the thickness direction of the electrode assembly 100. The fasteners 130 are installed on the multiple first electrode tabs 121 to gather them together to form the first electrode tab bundle 120, preventing the multiple first electrode tabs 121 from scattering and affecting the performance and lifespan of the electrode assembly 100. The fasteners 130 replace the traditional welding connection, avoiding the degradation of the material properties of the first electrode tabs 121 caused by welding heat, eliminating the risk of welding defects such as incomplete welding / over-welding, making the connection of the multiple first electrode tabs 121 more stable, and improving the safety and service life of the electrode assembly 100.

[0037] According to some embodiments of this application, refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of an electrode assembly 100 according to another embodiment of this application. The fastener 130 is a ring structure and is arranged around the outer periphery of the first electrode bundle 120.

[0038] In this embodiment, the fastener 130 adopts a ring structure with a through hole having a rectangular cross-section. After the first electrode, the second electrode, and the separator are wound or stacked, multiple first electrode ears 121 are stacked. After the multiple first electrode ears 121 are squeezed and shaped to form a first electrode ear bundle 120, the ring-shaped fastener 130 is fitted over the first electrode ear bundle 120. The ring-shaped fastener 130 can provide uniform constraint force in the circumferential direction of the first electrode ear bundle 120 to prevent the multiple first electrode ears 121 from spreading out in the thickness direction of the electrode assembly 100 or from being misaligned in the horizontal direction, thereby improving the safety and service life of the electrode assembly 100.

[0039] According to some embodiments of this application, the fastener 130 includes a first part and a second part, the first part and the second part being detachably connected to the outer periphery of the first pole ear bundle 120.

[0040] In this embodiment, the fastener 130 is a split design, comprising a detachably connected first part and a second part. The first part and the second part can be detachably connected by plugging or snapping, making the installation of the fastener 130 more convenient. Compared to an integrated design, the split fastener 130 can be made smaller, which can further tighten the first tab bundle 120 and prevent the multiple first tabs 121 from spreading out. Furthermore, the split fastener 130 facilitates later maintenance and disassembly, which is beneficial for tab separation during battery recycling. The first part and the second part can be detachably connected in the thickness direction or the width direction of the first tab bundle 120, without further limitation. It is understood that in other embodiments, the fastener 130 is an integrated annular structure with multiple first tabs 121 stacked. After the multiple first tabs 121 are compressed and shaped to form the first tab bundle 120, the annular fastener 130 is fitted over the first tab bundle 120 to constrain the multiple first tabs 121.

[0041] According to some embodiments of this application, the inner height of the fastener 130 is the sum of the thicknesses of the plurality of first tabs 121, and the inner width of the fastener 130 is the width of the first tabs 121.

[0042] In this embodiment, the inner height of the fastener 130 is equal to the product of the thickness of the first tab 121 and the number of first tabs 121, which is equal to the thickness of the first tab bundle 120; the inner width of the fastener 130 is equal to the width of the first tab 121, which is equal to the width of the first tab bundle 120, so that the size of the through hole inside the fastener 130 matches the size of the first tab bundle 120. The fastener 130 can be clamped to the outer periphery of the first tab bundle 120, thereby preventing the multiple first tabs 121 in the first tab bundle 120 from spreading out, and thus improving the safety and service life of the electrode assembly 100.

[0043] According to some embodiments of this application, refer to Figure 1 The first electrode bundle 120 is provided with electrode tab adhesive 140 near the first electrode plate. The distance between the fastener 130 and the electrode tab adhesive 140 is L1, and L1 satisfies: L1≥5mm.

[0044] In this embodiment, the tab adhesive 140 is a type of adhesive specifically used for encapsulating and fixing the battery tabs. The tab adhesive 140 is applied to the point where the first tab bundle 120 protrudes, sealing the gap between the first tab bundle 120 and the aluminum-plastic film, thus achieving a sealing and fixing effect. The distance between the fastener 130 and the tab adhesive 140 is L1, which must be greater than or equal to 5mm, such as 5mm, 6mm, 7mm, or any value between these values. The specific value should be selected based on the length of the first tab bundle 120. The distance between the fastener 130 and the tab adhesive 140 should not be too close, as this would cause the multiple first tabs 121 at the distal end of the first tab bundle 120 to spread out, thereby affecting the performance and safety of the electrode assembly 100.

[0045] According to some embodiments of this application, refer to Figure 1 The distance between the fastener 130 and the side of the first pole ear bundle 120 away from the first pole piece is L2, and L2 satisfies: L2>5mm.

[0046] In this embodiment, the distance between the fastener 130 and the edge of the first electrode bundle 120 away from the first electrode plate is L2. L2 satisfies a value greater than or equal to 5mm, such as 5mm, 6mm, 7mm, or any value between the above. The specific value should be selected according to the length of the first electrode bundle 120. The distance between the fastener 130 and the edge of the first electrode bundle 120 should not be too close. If the distance is too close, the middle of the multiple first electrodes 121 of the first electrode bundle 120 will easily spread out, thereby affecting the performance and safety of the electrode assembly 100.

[0047] According to some embodiments of this application, the fastener 130 is made of a conductive material.

[0048] In this embodiment, the fastener 130 is made of a conductive material, such as metals like copper, silver, and nickel, or non-metallic conductive materials like graphite. It is preferably made of a low-resistance material, such as copper or graphite, so as not to affect the conductivity of the first electrode ear bundle 120.

[0049] According to some embodiments of this application, refer to Figure 1 It also includes a second electrode bundle 150, which includes a plurality of second electrodes stacked together to form the second electrode bundle 150. The second electrodes are connected to second electrodes, and the ends of the second electrodes connected to the second electrodes are arranged along a first direction.

[0050] The number of fasteners 130 is at least one, and the fasteners 130 are respectively connected to the first pole ear bundle 120 and / or the second pole ear bundle 150 to fix the first pole ear bundle 120 and / or the second pole ear bundle 150.

[0051] In this embodiment, the electrode assembly 100 further includes a plurality of second electrode tabs connected to the second electrode sheet. After the second electrode sheet is stacked, the plurality of second electrode tabs are arranged in a first direction to form a second electrode tab bundle 150. The number of fasteners 130 is at least one, which are respectively installed on the first electrode tab bundle 120 and / or the second electrode tab bundle 150. The plurality of second electrode tabs in the second electrode tab bundle 150 are fixed by means of physical means, which can avoid welding defects such as incomplete welding / over-welding during ultrasonic welding, making the connection of the plurality of second electrode tabs more stable and improving the performance and safety of the electrode assembly 100.

[0052] This application also provides an electrochemical device, including any device in which an electrochemical reaction occurs to interconvert chemical energy and electrical energy, including, but not limited to, all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0053] In some embodiments, the electrochemical device includes the electrode assembly 100 as described above.

[0054] This application also provides an electronic device that includes the electrochemical device described above.

[0055] The electronic device described in this application is not particularly limited and can be applied to any electronic device known in the prior art.

[0056] According to some embodiments of this application, electronic devices include, but are not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, and android robots.

[0057] When the term "embodiment" is mentioned in the specification, it means that there is at least one embodiment in this application that includes the specific feature, structure, material, or characteristic. Therefore, expressions such as "in some embodiments," "in certain embodiments," and "exemplary" used throughout the document do not necessarily refer to the same embodiment. Furthermore, the specific feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments.

[0058] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments should not be construed as limiting the present application, and that changes, substitutions and modifications can be made to the embodiments without departing from the spirit, principles and scope of the present application.

Claims

1. An electrode assembly, characterized in that, It includes a first electrode, a second electrode, and a separator layered together, with the separator located between the first electrode and the second electrode; the first electrode and the second electrode have opposite polarities. The electrode assembly also includes: The first electrode bundle includes a plurality of first electrodes, which are stacked to form the first electrode bundle. The first electrodes are connected to the first electrode plate, and the ends of the first electrodes connected to the first electrode plate are arranged along a first direction, which is the thickness direction of the electrode assembly. Fasteners are installed on the first electrode bundle to secure the first electrode bundle.

2. The electrode assembly according to claim 1, characterized in that, The fastener is a ring-shaped structure and is arranged around the outer periphery of the first electrode bundle.

3. The electrode assembly according to claim 2, characterized in that, The fastener includes a first part and a second part, the first part and the second part being detachably connected to the outer periphery of the first pole ear bundle.

4. The electrode assembly according to claim 3, characterized in that, The inner height of the fastener is the sum of the thicknesses of the plurality of first tabs, and the inner width of the fastener is the width of the first tabs.

5. The electrode assembly according to any one of claims 1 to 4, characterized in that, The first electrode bundle is provided with electrode tab adhesive near the first electrode plate, and the distance between the fastener and the electrode tab adhesive is L1, wherein L1 satisfies: L1≥5mm.

6. The electrode assembly according to claim 5, characterized in that, The distance between the fastener and the side of the first electrode bundle away from the first electrode plate is L2, and L2 satisfies: L2≥5mm.

7. The electrode assembly according to any one of claims 1 to 4, characterized in that, The fastener is made of a conductive material.

8. The electrode assembly according to any one of claims 1 to 4, characterized in that, It also includes a second electrode bundle, which includes a plurality of second electrodes stacked together to form the second electrode bundle. The second electrodes are connected to the second electrode plate, and the ends of the second electrodes connected to the second electrode plate are arranged along the first direction. The number of fasteners is at least one, and the fasteners are respectively connected to the first electrode bundle and / or the second electrode bundle to fix the first electrode bundle and / or the second electrode bundle.

9. A battery cell, characterized in that, Includes the electrode assembly as described in any one of claims 1 to 8.

10. An electrochemical device, characterized in that, Including the battery cell as described in claim 9.

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