Method and system for angular rolling of electrode plates of battery cells
By introducing the electrode sheet at a non-zero angle during the calendering process, the problem of electrode sheet wrinkling was solved, and the uniformity and porosity of the electrode sheet were improved, thus ensuring the quality of the battery electrode.
Patent Information
- Application Number
- CN202411331190.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-08-07
- Filing Date
- 2024-09-24
- Publication Date
- 2026-02-10
AI Technical Summary
During the battery electrode production process, wrinkling often occurs in the calendering process, especially in the boundary area between the current collector and the active material layer, resulting in unevenness and poor porosity of the electrode sheet.
By introducing the electrode sheet into the calendering system at a non-zero angle, specifically at an angle of 25° to 90° relative to the calendering axis, and maintaining this angle during calendering, residual stress in the current collector is reduced, thereby reducing wrinkling while maintaining the desired porosity.
This effectively reduces wrinkling of the electrode sheets, improves their uniformity and porosity, and ensures the quality of the battery electrodes.
Smart Images
Figure CN121506847A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The information provided in this section is for the purpose of generally presenting the context of the disclosure. The work of the presently named inventors, to the extent the described is not common heritage, is not to be taken as an admission that the described contributions are prior art or warrant any particular scope of disclosure.
[0002] The present disclosure relates to the field of battery assemblies, and more specifically, to methods and systems for angling calendered electrode sheets to reduce electrode wrinkling. BACKGROUND
[0003] Electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles include one or more electric machines and a battery system including one or more battery cells, modules, and / or packs. A power control system is used to control the charging and / or discharging of the battery system during charging and / or driving.
[0004] A battery cell includes a cathode electrode, an anode electrode, and a separator arranged in a battery cell stack located in a battery cell housing (or battery cell can). The cathode electrode includes a layer of cathode active material arranged on a cathode current collector. The anode electrode includes a layer of anode active material arranged on an anode current collector. The cathode electrode and the anode electrode are connected to a cathode terminal and an anode terminal arranged on an outer surface of the housing.
[0005] A battery module or battery pack typically includes a housing that supports the cathode terminals and the anode terminals and surrounds the battery cells. The terminals of the battery cells are connected to respective ones of the cathode electrodes and the anode electrodes. The battery cells are interconnected to provide a desired output voltage. SUMMARY
[0006] A method of calendering an electrode sheet according to the present disclosure includes positioning the electrode sheet at an inlet of a calendering system, the calendering system including at least one roll defining a calendering axis, the electrode sheet including a layer of active material arranged on a portion of a current collector, the layer of active material including a first lateral side and a second lateral side opposite the first lateral side, a first uncoated portion arranged along the first lateral side of the layer of active material, and a second uncoated portion arranged along the second lateral side, the layer of active material being applied along a coating axis extending substantially parallel to the first lateral side and the second lateral side, directing the electrode sheet into the inlet with the coating axis at an angle relative to the calendering axis, and calendering the electrode sheet with the coating axis at a non-zero angle relative to the calendering axis.
[0007] In other features, calendering the electrode sheet at a non-zero angle of the coating axis relative to the calendering axis includes passing the electrode sheet through the calendering system with the coating axis arranged at about a 45° angle relative to the calendering axis.
[0008] In other features, calendering the electrode sheet at a non-zero angle of the coating axis relative to the calendering axis includes passing the electrode sheet through the calendering system with the coating axis arranged at about a 90° angle relative to the calendering axis.
[0009] In other features, calendering the electrode sheet at a non-zero angle of the coating axis relative to the calendering axis includes passing the electrode sheet through the calendering system with the coating axis arranged at an angle between 25° and 90° relative to the calendering axis.
[0010] According to the present disclosure, a system for calendering an electrode sheet includes a calendering member operable to apply a calendering pressure on the electrode sheet along a calendering axis at a non-zero angle relative to a coating axis, the electrode sheet including a layer of active material having a first lateral side and a second lateral side opposite the first lateral side, a first uncoated portion arranged along the first lateral side of the layer of active material and a second uncoated portion arranged along the second lateral side, the layer of active material defining the coating axis extending substantially parallel to the first lateral side and the second lateral side.
[0011] In other features, the alignment system is configured to position the electrode sheet at a non-zero angle relative to the calendering axis.
[0012] In other features, the alignment system includes a turntable configured to receive the electrode sheet in a first orientation with the coating axis substantially aligned with a travel axis of the system and to rotate the electrode sheet to a second orientation with the coating axis at a non-zero angle relative to the calendering axis.
[0013] In other features, the cutting system is operable to cut the electrode sheet into a selected length prior to processing by the alignment system.
[0014] In other features, the cutting system cuts the electrode sheet along a cutting axis substantially perpendicular relative to the coating axis.
[0015] In other features, the calendering member includes a first roller and a second roller, the first roller and the second roller moving through the electrode sheet along an axis at a non-zero angle relative to the coating axis.
[0016] In other features, the first roller includes a first roller axis and the second roller includes a second roller axis, the electrode sheet passing between the first roller and the second roller substantially perpendicular to the first roller axis and the second roller axis.
[0017] In other features, the first roll includes a first roll axis and the second roll includes a second roll axis, the electrode sheet passing between the first roll and the second roll substantially parallel to the first roll axis and the second roll axis.
[0018] In other features, the stationary calender member has a calender surface, the calender member configured to move along an axis at a non-zero angle relative to the coating axis on the calender surface.
[0019] In other features, the stationary calender member has a calender surface that supports the electrode sheet, the calender member including a plurality of rolls configured to apply a calender pressure to the electrode sheet along an axis at a non-zero angle relative to the coating axis.
[0020] In other features, the plurality of rolls includes a first roll having a first roll axis, a second roll having a second roll axis, a third roll having a third roll axis, and a fourth roll having a fourth roll axis, each of the first roll axis, the second roll axis, the third roll axis, and the fourth roll axis passing through the calender surface.
[0021] In other features, the plurality of rolls defines a roll system having a central axis of rotation.
[0022] In other features, the first roll is configured to rotate about the first roll axis, the second roll is configured to rotate about the second roll axis, the third roll is configured to rotate about the third roll axis, the fourth roll is configured to rotate about the fourth roll axis, and the roll system is configured to rotate about the central axis of rotation.
[0023] In other features, the first direction changing system is arranged upstream of the calender member and the second direction changing system is arranged downstream of the calender member.
[0024] In other features, the first direction changing system includes a first drum and the second direction changing system includes a second drum, the calender member arranged between the first drum and the second drum.
[0025] In other features, the winding spool is configured to wind the electrode sheet about an axis substantially parallel relative to the coating axis.
[0026] Other applicable fields of the disclosure will become apparent from consideration of the detailed description and drawings in conjunction with the claims. BRIEF DESCRIPTION OF DRAWINGS
[0027] The present disclosure will become more fully understood from the detailed description and drawings, wherein:
[0028] Figure 1 is a block diagram illustrating a calender system for calendering an electrode sheet at an angle to reduce electrode wrinkling in accordance with the present disclosure;
[0029] Figure 2 It is based on this disclosure Figure 1 A plan view of the electrode sheet to be rolled at a certain angle in the system;
[0030] Figure 3 This is a block diagram illustrating a system for a rolled electrode sheet according to one aspect of the present disclosure;
[0031] Figure 4 This is a block diagram illustrating a system for rolling electrode sheets according to another aspect of this disclosure;
[0032] Figure 5 This is a block diagram illustrating a system for rolling an electrode sheet at an angle according to one aspect of this disclosure;
[0033] Figure 6 This is a block diagram illustrating a system for rolling an electrode sheet at an angle, according to another aspect of this disclosure;
[0034] Figure 7 This is a block diagram illustrating a system for rolling an electrode sheet at an angle, according to another aspect of this disclosure;
[0035] Figure 8 Based on this disclosure Figure 7 A top view of a system for rolling electrode sheets;
[0036] Figure 9 This is a block diagram illustrating a system for rolling electrode sheets at an angle according to the present disclosure;
[0037] Figure 10 This is a block diagram illustrating a system for rolling electrode sheets at a certain angle according to another aspect of the present invention; and
[0038] Figure 11 This illustrates the use of the present disclosure for Figure 10 The flowcharts for the first and second directions of the system are shown.
[0039] In the accompanying drawings, reference numerals may be used repeatedly to identify similar and / or identical elements. Detailed Implementation
[0040] Although the battery cell formed according to this disclosure is described in the context of an electric vehicle, the battery cell can be used in stationary applications and / or other applications.
[0041] The battery cell includes multiple electrodes, each electrode comprising a current collector and an active material layer (e.g., a coating layer) coated on the current collector. The active material layer typically comprises a mixture of active materials, optional conductive fillers, and optional binders mixed together and coated onto the current collector. After the coating is applied, the electrodes pass through rollers that can be at room temperature or heated. The electrodes include a cathode electrode and an anode electrode that exchange lithium ions during charging and discharging.
[0042] Defects can occur during the calendering process in the production of battery electrodes. For example, differences in the material properties of the current collector and the active material layer can cause wrinkling of the electrode sheet. Wrinkling is particularly common along the boundary region between the active material layer and the current collector.
[0043] More specifically, the active material layer forms an internal coating region, leaving uncoated, exposed edges of the current collector on the opposite side of the active material. In the calendering process, very high compressive forces are typically applied to the current collector to achieve higher electrode density and thus lower electrode porosity. These very high compressive forces cause wrinkling along the edges of the active material layer.
[0044] The electrode calendering system and method disclosed herein provide a solution to reduce post-calendering wrinkling of the current collector by angulating the electrode sheet entering the calendering system. During the coating of the active material layer, this angle can be between approximately 25° and 90° relative to the direction of travel of the electrode sheet. By calendering at an angle relative to the direction of electrode coating, residual stress in the current collector is reduced, and wrinkling is thus mitigated, while still achieving the desired porosity.
[0045] Now for reference Figure 1 A block diagram of an exemplary calendering system 10 for reducing wrinkling after calendering is presented. Figure 1 The calendering system 10 and / or any other exemplary systems and methods described herein may be adapted to manufacture battery electrodes (e.g., anode and cathode electrodes) for vehicle applications and / or any other suitable applications including electrodes.
[0046] like Figure 1 As shown, the calendering system 10 includes a housing 12 having an inlet portion 14 and an outlet portion 16. A calendering mill system 20 is arranged within the housing 12 between the inlet portion 14 and the outlet portion 16. In one example, the calendering mill system 20 includes a first calendering member 22 shown as a first roll 23 and a second calendering member 24 shown as a second roll 25. Although depicted as rolls, the first calendering member 22 and / or the second calendering member 24 can take different forms, as will become more apparent herein.
[0047] The inlet portion 14 receives the electrode sheet 28, and the outlet portion 16 allows the electrode sheet 28 to pass through the housing 12 after calendering. The electrode sheet 28 can take various forms, including pre-cut sheets and continuous sheets. Figure 2 As shown, the electrode sheet 28 includes a first side edge 30 and opposing second side edges 32, a leading edge 34, and a trailing edge 36. According to this disclosure, as the name suggests, the leading edge 34 guides the electrode sheet 28 into the inlet portion 14. At this point, it should be understood that the term "sheet" is used to describe cut sheets of a defined length as well as continuous sheets stored on a roll.
[0048] Electrode sheet 28 includes a current collector 38 and an active material layer 40 coated onto a portion of the current collector 38. Electrode sheet 28 may be pressed and / or heated once or multiple times prior to calendering. In the example shown, electrode sheet 28 includes an active material layer 42 and an inactive material layer 44. In this example, active material layer 40 includes a first lateral side 48 and a second lateral side 50, the first lateral side 48 extending substantially parallel to and spaced apart from the leading edge 34, and the second lateral side 50 extending substantially parallel to and spaced apart from the trailing edge 36. Coating axis 54 extends through active material layer 40 between the first side edge 30 and the second side edge 32. Calendering axis 58 extends between the leading edge 34 and the trailing edge 36.
[0049] As will be detailed herein, the calendering axis 58 differs from the coating axis. In other words, the calendering axis 58 forms an angle (e.g., 90° or another non-zero angle) relative to the coating axis 54. For example, as Figure 3 As shown, the first calendering member 22 may have a roll axis 68 defining the axis of rotation of the first roll 23. The second calendering member 24 includes a roll axis (not shown) extending substantially parallel to the roll axis 68. Figure 3 In the diagram, the calendering axis 58 is shown as substantially parallel to the first side edge 30 and the second side edge 32, such that the leading edge 34 enters the calendering system 20 substantially parallel to the roll axis 68. Figure 4 In the diagram, the calendering axis 58 is shown at a 45° angle relative to the first side edge 30 and the second side edge 32, such that the leading edge 34 enters the calendering system 20 at an angle relative to the roll axis 68. According to this disclosure, the angle between the calendering axis 58 and the roll axis 68 can be between about 25° and about 90° to reduce wrinkling after calendering.
[0050] In either case, the coating axis 54 will be parallel to the roller axis 68. Figure 3 ) or at a certain angle relative to the roller shaft 68 ( Figure 4The inactive material layer 44 at the leading edge 34 passes through the calender system 20, ensuring that it enters between the first calender member 22 and the second calender member 24 before the active material layer 40. Guiding the leading edge 34 between the first calender member 22 and the second calender member 24 before applying pressure to the active material layer 40 ensures that the inactive material layer 44 is not initially under stress. When the calender axis 58 is perpendicular to or angled relative to the roll axis 68, the stress in the active material layer 40 is uniform between the first side edge 30 and the second side edge 32, resulting in reduced wrinkling. When the electrode sheet 28 is calendered to a selected porosity value (e.g., 25%), maintaining an angle of approximately 25° to approximately 90° between the calender axis 58 and the roll axis 68 produces less wrinkling than conventional methods.
[0051] exist Figure 5 The present disclosure describes a system 74 for forming an electrode sheet. System 74 includes a coating system 77 for applying an active material layer 40 to a current collector 38. According to the present disclosure, the electrode sheet 28 having the active material layer 40 is transferred from the coating system 77 to a cutting and holding system 80. The cutting and holding system 80 separates the electrode sheet 28 into individual sheets (not individually labeled).
[0052] The cutting and holding system 80 includes a cutter 82 arranged between a first clamp 84 and a second clamp 86. Electrode sheet 28 advances through the cutting and holding system 80, and the first clamp 84 and the second clamp 86 are activated. Once held in place, the cutter 82 moves along the cutting axis 90 through the electrode sheet. At this point, the individual electrode sheet is conveyed onto a rotary table 92 that rotates about the table axis 94. The individual electrode sheet is then passed to the calender system 20 in the desired orientation, positioning the calender axis 58 at a selected angle relative to the roll 68, for example, between approximately 25° and approximately 90°. The individual sheet is calendered and passes substantially wrinkle-free from the exit section 16.
[0053] exist Figure 6 The present disclosure describes a system 100 for forming an electrode sheet according to another aspect of the present disclosure. System 100 includes a calender system 104 having a fixed calendering member 106 including a calendering surface 108 and a rotatable calendering member 110 having a roll axis 112. An electrode sheet 28 passes through a coating system 77 along a coating axis 54. The electrode sheet 28 is then transferred from the coating system 77 to the calendering surface 108 of the fixed calendering member 106.
[0054] like Figure 7As shown, electrode sheet 28 moves along coating axis 54 on calender surface 108 and is collected on roll 114. As electrode sheet 28 translates on calender pressure surface 108, rotatable calender member 110 rotates about roll axis 112 and translates laterally along calender axis 58 across calender pressure surface 108. Although calender axis 58 is shown as extending substantially perpendicular to coating axis 54, rotatable calender member 110 can be arranged relative to coating axis 54 at any desired non-zero calender angle.
[0055] exist Figure 8 The image shows a system for forming an electrode sheet 120 according to the present disclosure. System 120 includes a calender system 122, which includes a first calendering member 128 shown as a first roll 130 and a second calendering member 132 shown as a second roll 134. The first roll 130 includes a first roll axis 136, and the second roll 134 includes a second roll axis 138. Upon exiting the coating system 77, the electrode sheet 28 passes between the first roll 130 and the second roll 134, wherein the coating axis 54 is substantially parallel to the first roll axis 136 and the second roll axis 138. The first roll 130 and the second roll 134 translate laterally along the calendering axis 58, except for rotation about the respective roll axes of the first roll axis 136 and the second roll axis 138. Although the calendering axis 58 is shown extending substantially perpendicularly to the coating axis 54, the first roll 130 and the second roll 134 can be arranged relative to the coating axis 54 at any desired non-zero calendering angle (e.g., about 25° to about 90°).
[0056] Now refer to Figure 9 The same reference numerals denote corresponding components in the respective views, according to the system 145 for forming electrode sheets of this disclosure. System 145 includes a calender system 154, which includes a fixed calendering member 156 having a calendering surface 158. Calender system 154 is also shown as including a first rotatable calendering member 161 shown as a first roll 162, a second rotatable calendering member 164 shown as a second roll 165, a third rotatable calendering member 167 shown as a third roll 168, and a fourth rotatable calendering member 170 shown as a fourth roll 171.
[0057] According to this disclosure, the first roll 162 includes a first roll axis 177, the second roll 165 includes a second roll axis 179, the third roll 168 includes a third roll axis 181, and the fourth roll 171 includes a fourth roll axis 183. The first roll axis 177, the second roll axis 179, the third roll axis 181, and the fourth roll axis 183 project through the calendering surface 158. In addition to rotating about each respective roll axis, the first roll 162, the second roll 165, the third roll 168, and the fourth roll 171 rotate as a system about a central rotation axis 186.
[0058] As the electrode sheet 28 exits the coating system 77, it travels along the coating axis 54 on the calendering surface 158. The first roll 162, second roll 165, third roll 168, and fourth roll 171 rotate about their respective axes 177, 179, 181, and 183, applying pressure to the electrode sheet 28 against the calendering surface 158. Furthermore, the first roll 162, second roll 165, third roll 168, and fourth roll 171 rotate about the central rotation axis 186. With this arrangement, as the electrode sheet 28 passes through the calendering system 154, the calendering axis 58 will always be at a non-zero angle relative to the coating axis 54, resulting in minimal wrinkles (if any) after calendering.
[0059] Now refer to Figure 10 and Figure 11 In describing a system 198 for forming electrode sheets according to another aspect of this disclosure, the same reference numerals denote corresponding portions in the respective views. System 198 includes a calender system 204 arranged between a first orientation-changing system 206 and a second orientation-changing system 208. The first orientation-changing system 206 may be in the form of a first drum 210, and the second orientation-changing system 208 may be in the form of a second drum 212. Of course, the first orientation-changing system 206 and the second orientation-changing system 208 may take various forms, including spools, rollers, etc.
[0060] The calender system 204 includes a first rotatable calendering member 214 and a second rotatable calendering member 216. The first rotatable calendering member 214 includes a first roll axis 218, and the second rotatable calendering member 216 includes a second roll axis 220. Figure 11 As shown, the first orientation changing system 206 forces the electrode sheet 28 to pass between the first rotatable calendering member 214 and the second rotatable calendering member 216, such that the coating axis is substantially parallel to each of the first roller axis 218 and the second roller axis 220.
[0061] As the electrode sheet 28 passes through the calender system 204, the first rotatable calender member 214 and the second rotatable calender member 216 travel laterally, except for rotation. In this way, the calender axis 58 is substantially perpendicular to the coating axis 54. With this arrangement, as the electrode sheet 28 passes through the calender system 154, the calender axis 58 will always be at a non-zero angle relative to the coating axis 54, resulting in very few wrinkles (if any) after calendering.
[0062] The terms “about” and “substantially” are intended to include the degree of error associated with a measurement based on a specific quantity of equipment available at the time of application submission. For example, “about” and “substantially” can include a range of ±8% for a given value.
[0063] The foregoing description is merely illustrative in nature and is in no way intended to limit this disclosure, its application, or use. The broad teachings of this disclosure can be implemented in various forms. Therefore, while this disclosure includes specific examples, its true scope should not be limited thereto, as other modifications will become apparent upon examination of the drawings, specification, and appended claims. It should be understood that one or more steps within the method may be performed in a different order (or simultaneously) without altering the principles of this disclosure. Furthermore, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of this disclosure may be implemented in and / or combined with features of any other embodiment, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and substitutions of one or more embodiments for each other remain within the scope of this disclosure.
[0064] Spatial and functional relationships between components (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connection,” “joint,” “coupled,” “adjacent,” “closely adjacent,” “on top,” “above,” “below,” and “set.” Unless explicitly described as “direct,” when describing the relationship between a first component and a second component in the foregoing disclosure, the relationship can be a direct relationship in which no other intermediate components exist between the first component and the second component, or an indirect relationship (spatially or functionally) in which one or more intermediate components exist between the first component and the second component. As used herein, the phrase at least one of A, B, and C should be interpreted as indicating logic using non-exclusive OR (A OR B OR C) and should not be interpreted as indicating “at least one of A, at least one of B, and at least one of C.”
Claims
1. A method for rolling an electrode sheet, comprising: An electrode sheet is positioned at the entrance of a calendering system, the calendering system including at least one roll defining a calendering axis, the electrode sheet including an active material layer disposed on a portion of a current collector, the active material layer including a first lateral side and a second lateral side opposite to the first lateral side, a first uncoated portion disposed along the first lateral side of the active material layer and a second uncoated portion disposed along the second lateral side, the active material layer being applied along a coating axis that extends substantially parallel to the first lateral side and the second lateral side; The electrode sheet is guided into the inlet, wherein the coating axis is angled relative to the rolling axis; as well as The electrode sheet is rolled, wherein the coating axis is at a non-zero angle relative to the rolling axis.
2. The method of claim 1, wherein rolling the electrode sheet at a non-zero angle relative to the rolling axis comprises passing the electrode sheet through the rolling system, wherein the coating axis is arranged at an angle of approximately 45° relative to the rolling axis.
3. The method of claim 1, wherein rolling the electrode sheet at a non-zero angle relative to the rolling axis comprises passing the electrode sheet through the rolling system, wherein the coating axis is arranged at an angle of approximately 90° relative to the rolling axis.
4. The method of claim 1, wherein rolling the electrode sheet at a non-zero angle relative to the rolling axis comprises passing the electrode sheet through the rolling system, wherein the coating axis is arranged between an angle of 25° and 90° relative to the rolling axis.
5. A system for calendering an electrode sheet, the electrode sheet comprising an active material layer, a first uncoated portion, and a second uncoated portion, the active material layer having a first lateral side and a second lateral side opposite to the first lateral side, the first uncoated portion being disposed along the first lateral side of the active material layer, the second uncoated portion being disposed along the second lateral side, the active material layer defining a coating axis extending substantially parallel to the first lateral side and the second lateral side, the system comprising: A calendering member operable to apply calendering pressure on the electrode sheet at a non-zero angle relative to the coating axis along the calendering axis.
6. The system according to claim 5, further comprising: An alignment system configured to position the electrode sheet at the non-zero angle relative to the rolling axis.
7. The system according to claim 5, wherein, The calendering member includes a first roller and a second roller, which move on the electrode sheet along an axis that is at a non-zero angle relative to the coating axis.
8. The system according to claim 7, wherein, The first roller includes a first roller axis, and the second roller includes a second roller axis, with the electrode sheet passing between the first roller and the second roller substantially perpendicular to the first roller axis and the second roller axis.
9. The system of claim 5, further comprising: a fixed calendering member having a calendering surface, the calendering member being configured to move on the calendering surface along an axis at a non-zero angle relative to the coating axis.
10. The system according to claim 5, comprising a first direction-changing system disposed upstream of the rolling member and a second direction-changing system disposed downstream of the rolling member.