Battery cell and battery
By using a spiral arrangement of positive and negative electrode plates and a separator, the defects of winding and stacking processes in lithium battery assembly are solved, achieving a battery design with high efficiency, low burrs, long lifespan, and high yield.
Patent Information
- Application Number
- CN202423130085.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2034-12-18
AI Technical Summary
Existing lithium battery assembly processes suffer from problems such as high tension control precision and easy lithium deposition in wound cells, and cumbersome production and low yield of burr-prone cells in stacked cells.
The positive and negative electrodes are arranged in a spiral shape and combined with a separator. The electrodes do not need to be wound or stacked. They are connected by the straight and bent sections of the spiral coil to form a single electrode structure that does not need to be cut, ensuring the stability of the electrodes and the insulation of the separator.
It improves battery production efficiency, reduces the possibility of burr formation, extends cell lifespan, increases yield and cycle capacity retention, and enhances cell stability and space utilization.
Smart Images
Figure CN223771131U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and more specifically, to a battery cell and a battery. Background Technology
[0002] A lithium battery consists of a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a lithium battery, lithium ions need to migrate between the positive and negative electrodes. Therefore, in order to reduce the obstruction of lithium ions during their movement and improve the charging and discharging efficiency of the battery, it is necessary to ensure that the positive and negative electrodes are spaced apart and to place a separator between the positive and negative electrodes to prevent short circuits during the assembly process of the lithium-ion battery.
[0003] Currently, there are two main assembly processes for lithium batteries: winding and stacking. Winded cells have a high degree of automation, but require high precision in controlling the winding tension, and lithium plating is prone to occur at the rounded corners. Stacked cells have a more complex manufacturing process, are prone to burrs, and have a lower yield, but offer higher space utilization. Both existing assembly processes have their advantages and disadvantages and urgently need improvement.
[0004] Therefore, there is an urgent need to invent a new type of battery cell and battery. Utility Model Content
[0005] One of the objectives of this utility model is to provide a battery cell that addresses the shortcomings of existing technologies by eliminating the need for winding the electrodes, preventing lithium plating at corners, and simplifying the electrode stacking assembly process.
[0006] To solve the above-mentioned technical problems, this application adopts the following technical solution:
[0007] A battery cell is provided, comprising a positive electrode, a negative electrode, and a separator arranged spirally along the thickness direction of the electrode. The positive electrode and the negative electrode have multiple spiral coils connected in sequence along the spiral direction. Each spiral coil includes at least one straight section and at least one bent section. The positive electrode and the negative electrode abut against each other along the spiral direction. The separator is disposed between the positive electrode and the negative electrode.
[0008] Specifically, the width of the bent section is the same as the width of the straight section.
[0009] Specifically, the bent segment is designed as a ring.
[0010] Specifically, the spiral ring has an axially oriented through hole in its center.
[0011] Specifically, the projection of the spiral coil in the thickness direction of the battery cell is racetrack-shaped.
[0012] Specifically, it also includes tabs, which are disposed at the tail and / or head of the positive electrode and the negative electrode.
[0013] Specifically, the tab is disposed on the side of the battery cell.
[0014] Specifically, the width of the separator is greater than the larger of the width of the positive electrode and the width of the negative electrode, and the separator extends beyond the inner and outer edges of the positive and negative electrodes.
[0015] Specifically, both the positive electrode and the negative electrode include a current collector and an active material coating applied to both sides of the current collector in the thickness direction.
[0016] The beneficial effects of this utility model are as follows: Since the positive and negative electrode sheets are spirally arranged and assembled along the spiral direction, the positions of the positive and negative electrode sheets will not interfere with each other. Both the positive and negative electrode sheets can be set as single electrode sheets and assembled along the spiral direction, eliminating the need for multiple stacking of the electrode sheets, resulting in high production efficiency. Furthermore, the electrode sheets do not need to be cut, reducing the possibility of burrs and increasing the yield rate of the battery cell. Moreover, the spiral assembly method does not bend the electrode sheets, thus preventing corner lithium plating, resulting in a longer battery cell lifespan and higher cycle capacity retention.
[0017] The second objective of this utility model is to provide a battery that includes the aforementioned battery cell. Attached Figure Description
[0018] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and are used to explain the present invention, but do not constitute an undue limitation of the present invention. In the drawings:
[0019] Figure 1 This is a schematic diagram of the structure of this utility model;
[0020] Figure 2 This is a top view of the present invention;
[0021] Figure 3 This is a side view of the present invention;
[0022] Figure 4 This is a schematic diagram showing the position of the electrode tab of this utility model.
[0023] Wherein: 1-positive electrode; 2-separator; 3-negative electrode; 4-spiral coil; 41-straight section; 42-bent section; 5-side; 6-tab. Detailed Implementation
[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the 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. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application.
[0025] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0026] Although this application discloses preferred embodiments as described above, it is not intended to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.
[0027] The manufacturing process of stacked batteries includes electrode cutting, electrode stacking, and encapsulation. In the electrode cutting process, the electrodes need to be divided into multiple parts of suitable size. In this process, it is necessary to ensure that the shape and size of each electrode are consistent. In the electrode stacking process, multiple electrodes need to be stacked alternately, and the position of multiple electrodes in the stacking process needs to be accurate. Because the electrodes of stacked batteries are cut multiple times, burrs are easily generated on the electrodes, which can cause short circuits in the battery and reduce the yield rate. Furthermore, due to the accuracy requirements in the stacking and cutting processes, the production efficiency of the electrodes is relatively low and the requirements for equipment are high.
[0028] The manufacturing process of wound battery cells includes electrode winding and encapsulation. During the electrode winding process, positive electrode, negative electrode, and separator are stacked layer by layer, and these layers are wound into a cylindrical battery cell by a winding machine. Since the electrode does not need to be cut or stacked, the electrode winding process is highly efficient. However, because the electrode needs to be bent during the winding process, the active material of the electrode is compressed and stretched at the bending point, which makes the wound battery prone to corner lithium plating, reducing the cycle capacity retention rate and service life of the wound battery.
[0029] Therefore, this application combines the advantages of wound batteries and stacked batteries to change the electrode sheet to be made in a single sheet form without cutting and assembled in a stacked manner. Since the electrode sheet is a single sheet, the cutting process is simpler and more efficient, and the stacked assembly method does not require bending the electrode sheet, which is less likely to cause lithium plating on the electrode sheet.
[0030] Implementation Method 1
[0031] like Figure 1-4 As shown, this application provides a battery cell including a positive electrode 1, a negative electrode 3, and a separator 2 arranged spirally along the thickness direction of the electrode. The positive electrode 1 and the negative electrode 3 are provided with a plurality of spiral coils 4 connected in sequence along the spiral direction. The spiral coil 4 includes at least one straight section 41 and at least one bent section 42. The spiral coil 4 is formed by rotating the electrode one revolution along the axis of the spiral direction. The positive electrode 1 and the negative electrode 3 abut against each other along the spiral direction. The separator 2 is disposed between the positive electrode 1 and the negative electrode 3.
[0032] For example, the spiral coils 4 can be set to the same size, and the bent section 42 of the lower spiral coil 4 and the straight section 41 of the corresponding upper spiral coil 4 are connected to realize the stacking of multiple spiral coils 4, so that the spiral shape of the electrode sheet is continuously spiraled upward along the axis of the spiral. The spiral-shaped battery cell of this application has better stability than the wound battery cell and the stacked battery cell. The wound battery cell needs to bend the electrode sheet during the winding process. After the winding is completed, there is stress in the electrode sheet. The stacked battery cell has multiple electrode sheets. When the battery cell is impacted, the impact force on the electrode sheet is difficult to disperse, which can easily cause the electrode sheet to become skewed. However, the battery cell electrode sheet of this application does not have stress and the electrode sheet is set as a whole, which has a better effect on dispersing the impact force on the battery cell. The battery cell of this application has better stability.
[0033] This application arranges the positive and negative electrode sheets 3 and the separator 2 in a spiral shape along the thickness direction of the electrode sheets. This allows the positive and negative electrode sheets 3 to be stacked in a spiral shape, preventing interference between their movement paths during the spiral stacking process. Both the positive and negative electrode sheets 3 can be stacked continuously as single sheets. Since the positive and negative electrode sheets 3 can be set as single sheets, there is no need to cut them, simplifying the battery manufacturing process and improving production efficiency. Furthermore, because the electrode sheets do not need to be cut, there are no burrs, reducing the possibility of short circuits caused by burrs puncturing the separator 2, resulting in a higher yield rate for the battery cells. Moreover, the battery cells in this application are stacked in a spiral direction. The positive and negative electrode sheets 3 are not bent during assembly, which would compress or stretch the active material layer coated on the electrode sheets, causing damage to the structure of the active material layer and making the cell prone to lithium plating. The spiral cell structure of this application is different from the previous stacked and wound structures. This structure can combine the technical advantages of both and solve the inherent defects of the two structures. Theoretically, the cell produced by using this structure can improve the service life. The spiral coil 4 of the cell of this application is provided with two straight sections 41 and two bent sections 42. The straight section 41 has a higher space utilization rate, which makes the energy density of the battery higher; while the bent section 42 can better connect the different spiral coils 4 to complete the spiral arrangement of the electrode sheets.
[0034] Preferably, the width of the bent section 42 is the same as the width of the straight section 41. When the widths of the bent section 42 and the straight section 41 are set to be the same, the generation of the electrode sheet is simpler, and the electrode sheet of this application can be obtained by spirally bending a roll of electrode sheet.
[0035] Preferably, the bending segment 42 is set as a ring, and the ring shape is more conducive to bending the electrode into a suitable shape during the electrode formation process.
[0036] In some embodiments, the bending segment 42 can be configured with different shapes to adapt to batteries of different shapes, such as the bending segment 42 can be configured as a rectangle to adapt to a square battery.
[0037] Preferably, a through hole is provided in the middle of the spiral coil 4 along the axial direction, which is the thickness direction of the battery cell and also the direction of the spiral stacking of the electrode sheets. The through hole enables the battery cell to have better heat dissipation function, and the size and shape of the through hole can be set to provide the installation position of the device. Since the through hole is stacked, it is different from the through hole of the wound battery cell. The influence of the shape of the through hole on the electrode stress during the electrode winding process needs to be considered. The through hole of this application can be set in a variety of shapes.
[0038] Preferably, the projection of the spiral coil 4 in the thickness direction of the cell is racetrack-shaped. The racetrack-shaped cell is easier to dissipate heat and has better space utilization.
[0039] like Figure 4 As shown, specifically, it also includes tabs, which are set at the tail and / or head of the positive electrode 1 and the negative electrode 3. Setting the tabs at the head or tail of the electrode occupies less space in the cell and can improve the space utilization of the cell.
[0040] Specifically, placing the tabs on the side 5 of the battery cell helps to shorten the current travel path and improve the charging and discharging performance of the battery cell.
[0041] Specifically, the width of the separator 2 is greater than the larger of the widths of the positive electrode 1 and the negative electrode 3, so that the separator 2 can better achieve insulation between the positive and negative electrode 3. Furthermore, the separator 2 extends beyond the inner and outer edges of the positive electrode 1 and the negative electrode 3. Since the electrode is spirally arranged, it is necessary to control the insulation between the positive and negative electrode 3 at the through hole.
[0042] Specifically, both the positive electrode 1 and the negative electrode 3 include a current collector and an active material coating on both sides of the current collector in the thickness direction. The spiral electrode with double coating helps to improve space utilization.
[0043] The head and tail of the positive electrode 1 and the negative electrode 3 are respectively set at both ends of the cell length direction, which can prevent the height difference between the head and tail from being concentrated in one place and prevent lithium plating of the battery when the electrode is under pressure.
[0044] Implementation Method 2
[0045] This application also provides a battery including the above-mentioned battery cell. The battery can be a soft-pack battery or a hard-shell battery. Since the battery cell of this application is a spiral electrode cell, it can be adapted to batteries of various types of casings. This application is applicable to all battery types that can be used with stacked cells or wound cells.
[0046] Preferably, the battery cell of this application is used in a pouch cell, which has high energy density, light weight, good flexibility and customizability. The spiral electrode cell design enables the battery to achieve higher volumetric efficiency and adapt to the shape and size of the pouch cell, which is particularly advantageous in applications requiring lightweight and high energy density.
[0047] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the present invention's conception through the foregoing teachings or related technical or knowledge. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be protected within the scope of the appended claims.
Claims
1. An electric cell, characterized by: The electrode plate (1) and the negative electrode plate (3) are in contact with each other along the spiral direction, and the separator (2) is arranged between the positive electrode plate (1) and the negative electrode plate (3).
2. The cell of claim 1, wherein: The width of the bending section (42) is the same as the width of the flat section (41).
3. The cell of claim 2, wherein: The bending section (42) is arranged in a circular ring shape.
4. The cell of claim 1, wherein: The spiral turns (4) are provided with a through hole arranged along the axial direction.
5. The cell of claim 3, wherein: The projection of the spiral turns (4) in the thickness direction of the battery cell is in the shape of a racetrack.
6. The cell of claim 1, wherein: The tab (6) is arranged at the tail and / or head of the positive electrode plate (1) and the negative electrode plate (3).
7. The cell of claim 6, wherein: The tab (6) is arranged at the side (5) of the battery cell.
8. The cell of claim 1, wherein: The width of the separator (2) is greater than the greater width of the width of the positive electrode plate (1) and the width of the negative electrode plate (3), and the separator (2) exceeds the inner edge and the outer edge of the positive electrode plate (1) and the negative electrode plate (3).
9. The cell of claim 1, wherein: The positive electrode plate (1) and the negative electrode plate (3) each comprise a current collector and an active material coating layer coated on both sides of the current collector in the thickness direction.
10. A battery, characterized by: The battery cell of any one of claims 1-9.