Capacitor core and metallized film winding type flattening capacitor
By employing a staggered design, a metallized layer with a waveform profile, and an anchoring connection structure, the problem of micro-defects in traditional capacitors easily developing into through-channels is solved, thereby improving the safety and lifespan of the capacitor and ensuring the stability of the electrodes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-22
- Publication Date
- 2026-03-10
AI Technical Summary
Traditional metallized film capacitors have microscopic defects in their interlayer structure that can easily develop into low-impedance breakdown channels that penetrate multiple dielectric layers, leading to capacitor failure. Furthermore, the metal layers are prone to detachment due to thermal stress.
The metallization layer, which employs a misaligned design and a wave-shaped profile, combined with an anchoring connection structure, including axial and circumferential misalignment, wavy or sawtooth edges, and an anchoring connection structure such as an array of pits or grooves, forms a composite misalignment and mechanical interlock, isolating defects and enhancing bonding strength.
It effectively blocks penetrating breakdown channels, improves the safety margin and service life of capacitors, ensures the integrity of electrodes under extreme temperatures, and reduces the risk of partial discharge.
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Figure CN121641689A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of capacitors, in particular to a capacitor core and a metalized film wound and flattened type capacitor comprising the capacitor core. BACKGROUND
[0002] Metalized film capacitors are widely used in new energy, industrial control, consumer electronics and automotive electronics due to their self-healing characteristics, high specific capacity and good frequency characteristics. The core component of the capacitor core is usually made by winding the base film with a metalized layer on the surface into a cylinder, and then through processes such as flattening and end face gold spraying.
[0003] However, in the interlayer structure, the traditional winding process pursues strict alignment of the edges of each layer of film. This alignment structure causes the microscopic defects that may exist on each layer of film to be highly overlapped in the vertical direction, such as mechanical damage, impurity points, abnormal crystal rings, burst points, pinholes, etc. generated in the process of base film drawing or metalized film vacuum evaporation. When the metalized film capacitor is used as a high-voltage capacitor, a pulse capacitor, a filter capacitor or an absorption capacitor, etc., these aligned defect points are prone to develop into low-impedance breakdown channels that penetrate through multiple layers of dielectric. SUMMARY
[0004] The present application provides a capacitor core and a metalized film wound and flattened type capacitor to solve the problems in the prior art. The specific technical solutions are as follows: On the one hand, the present application provides a capacitor core, comprising at least two layers of metalized films stacked in sequence, wherein the metalized film comprises a film substrate and a metalized layer on at least one surface thereof. In the multiple layers of metalized films, at least two adjacent layers of metalized films are arranged offset to each other in the stacking direction, and the offset arrangement comprises axial offset and / or circumferential offset.
[0005] As a further technical solution of the present application, the axial offset is that the corresponding side edges of the two adjacent layers of metalized films are offset to each other in the direction parallel to the winding core axis.
[0006] As a further technical solution of the present application, the circumferential offset is that the metalized layer patterns of the two adjacent layers of metalized films are rotated by an angle around the core center axis in the projection plane perpendicular to the winding core axis.
[0007] As a further technical solution of the present application, when the number of metalized films is three or more, all the metalized films form alternating odd layers and even layers in the stacking direction, the metalized films of the odd layers correspond to each other, the metalized films of the even layers correspond to each other, and the metalized films of the odd layers and the metalized films of the even layers are arranged offset to each other.
[0008] As a further technical solution of the present application, the metallization layer has a wave-shaped profile at at least one side edge of its planar pattern.
[0009] As a further technical solution of the present application, the wave-shaped profile is a wavy shape or a zigzag shape.
[0010] As a further technical solution of the present application, the wave-shaped profile of the metallization layer is entirely located inside the physical edge of the thin-film substrate to form a margin area on the thin-film substrate.
[0011] As a further technical solution of the present application, an anchoring connection structure is provided on at least one surface of the thin-film substrate that carries the metallization layer, and the metallization layer covers and fills the anchoring connection structure.
[0012] As a further technical solution of the present application, the anchoring connection structure is an array of concave structures regularly arranged on the bonding surface of the anchoring connection structure. and / or, the anchoring connection structure is a network of grooves staggered on the bonding surface of the thin-film substrate.
[0013] In another aspect, the present application also provides a metallized thin-film roll-type squashed capacitor, comprising the capacitor core of any of the above technical solutions.
[0014] The beneficial effects of the present application are as follows: By introducing the interlayer misalignment structure, the spatial alignment of micro defects in each layer in the vertical direction is actively destroyed, and even if there are defects in a single layer, the upper and lower adjacent layers at the corresponding positions are all intact dielectric, thereby "isolating" the defects and blocking the path of developing into a through-type breakdown channel, which changes the failure mode of the capacitor from "sudden short circuit" to a gentle "capacity attenuation", and the safety margin and service life are improved by orders of magnitude.
[0015] The edge of the metallization layer is designed as a wavy or zigzag shape, which completely eliminates the geometric sharp end of the traditional straight edge. This design enables smooth transition of the electric field from the metal conductor to the dielectric, effectively dispersing the edge field strength. At the same time, by precisely controlling the small margin at the wave peak, the process feasibility and long-term insulation reliability are taken into account while ensuring the optimization effect of the electric field, thereby reducing the partial discharge of the capacitor.
[0016] Preparation of micro-pit array or groove network on the surface of the film substrate as anchoring structure, so that the subsequent metal layer is embedded and filled in, forming a firm three-dimensional mechanical interlocking. This "bulk anchoring" mechanism will combine the force from the fragile physical adsorption to strong mechanical combination, greatly improve the metal layer peeling strength, fundamentally solve the problem of metal layer falling caused by thermal stress, ensure the integrity of the electrode under extreme temperature cycle, so as to ensure the long-term stability of the capacitor parameters. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 The dislocation structure of the multi-layer metalized film in the stacked state when laid is shown. Figure 2 The schematic diagram of the metalized film itself is shown. Figure 3 The schematic diagram of the waveform profile of the metalized layer edge is shown. Figure 4 The schematic diagram of the array pit structure on the bonding surface of the film substrate is shown. Figure 5 The schematic diagram of the groove network on the bonding surface of the film substrate is shown.
[0018] BRIEF DESCRIPTION OF DRAWINGS: 1, metalized film; 11, film substrate; 111, anchoring structure; 12, metalized layer; 13, blank area. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the present application will be described clearly and completely in combination with the embodiments.
[0020] The present embodiment provides a capacitor core of a metalized film wound and flattened capacitor, which is formed by winding and flattening a plurality of stacked metalized films 1. In the present application, only the metalized film 1 itself and the stacked state of the plurality of metalized films 1 before winding are improved, and the specific winding and flattening operation is not involved.
[0021] The following will be combined Figures 1-5 The capacitor core is described in detail.
[0022] Figure 1In the capacitor core, the capacitor core comprises at least two layers of metalized films 1 arranged in sequence, and the adjacent two layers of the metalized films 1 are arranged in a staggered manner in the stacking direction; the staggered design actively destroys the vertical alignment relationship of the defect points of each layer in the physical space, that is, even if there is a defect at a certain position of a certain layer, the corresponding positions of the adjacent upper and lower layers are complete media, so that the defect is "isolated" in the local, avoiding the formation of a weak path, effectively preventing a single defect from developing into a low-impedance breakdown channel penetrating through the entire core thickness.
[0023] Specifically, the stagger of the adjacent two layers of the metalized films 1 includes axial stagger: before winding, the multiple layers of the metalized films 1 are in a flat stacked state, at this time, the adjacent two metalized films 1 are staggered in the width direction of the metalized film 1, and when the multiple layers of the metalized films 1 are wound into a core, the width direction of the metalized film 1 in the flat state is changed into the axial direction of the core, and the axial stagger of the adjacent two layers of the metalized films 1 is completed.
[0024] Specifically, the stagger of the adjacent two layers of the metalized films 1 includes circumferential stagger: before winding, the multiple layers of the metalized films 1 are in a flat stacked state, at this time, the adjacent two layers of the metalized films 1 are staggered in the length direction of the metalized film 1, and when the multiple layers of the metalized films 1 are wound into a core, the length direction of the metalized film 1 in the flat state is changed into the circumferential direction of the core, and the circumferential stagger of the adjacent two layers is completed.
[0025] In combination with the above description of the stagger of the adjacent two layers of the metalized films 1, the core of the application realizes a complex stagger structure in three-dimensional space, specifically: the axial stagger and the circumferential stagger are independent of each other and can be implemented alone or jointly, when the two are combined, the relative positions of the adjacent two layers of the film in the core formed by winding are offset in the axial direction (the side surface direction of the core) and the circumferential direction (the direction around the center of the core). This combination completely offsets the corresponding points on the two layers of the film in three-dimensional space; the single axial stagger mainly blocks the straight-line breakdown path along the radial direction (i.e. the thickness direction) of the core; and after superimposing the circumferential stagger, the geometric conditions for forming a penetrating channel along any possible inclined or spiral path are further destroyed, completely "encapsulating" the local defects on any single layer of the film in the normal adjacent medium, significantly improving the ability to resist breakdown under complex electric field distribution.
[0026] Further, when the number of the metalized films 1 is three or more, the positions of the multiple layers of the metalized films 1 in the stacking direction are alternately corresponding; that is, if the multiple layers of the metalized films 1 arranged in sequence in the stacking direction are sequentially numbered, then the positions of the metalized films 1 of the odd layers are the same, the positions of the metalized films 1 of the even layers are the same, and the metalized films 1 of the odd layers are staggered with the metalized films 1 of the even layers in the axial direction, for example Figure 1If the defect points on the metallized film 1 are set as G points, then in the axial direction, the G points of odd layers correspond to the G points of even layers, and the G points of odd layers are staggered with the G points of even layers; all odd layers and all even layers are set to be aligned in the axial direction to form two groups of film layer groups staggered with each other, and this design can achieve more uniform defect distribution and more stable internal stress field.
[0027] Figure 2 and Figure 3 In the above, the metallized film 1 includes a film substrate 11 and a metallized layer 12 formed on at least one surface thereof, the metallized layer 12 has a wave-shaped profile at at least one side edge of a planar pattern thereof, and the wave-shaped profile of the metallized layer 12 is entirely located inside a physical edge of the film substrate 11 to form a margin area 13 on the film substrate 11; the traditional straight edge is changed to a wave-shaped edge, so that the electric field distribution of the edge of the metallized layer 12 is changed to be more gentle and local peaks are avoided; for example Figure 3 As shown in the above, the edge of the metallized layer 12 is set to a sine wave shape, which has a wave peak P point and a wave valley V point, the margin distance of the P point to the edge of the film substrate 11 is a minimum value d1, d1 can be greater than a certain value, for example, d1 is greater than 0.2 mm, to ensure that the slitting process does not damage the metallized layer 12 and has sufficient safety margin, and the margin distance of the V point to the edge of the film substrate 11 is a maximum value d2, d2 can be less than a certain value to limit the area ratio of the margin area 13, for example, d2 is less than 1 mm, to ensure the size of the battery cell and the electric field distribution during work.
[0028] An anchor connection structure 111 is arranged on at least one surface of the film substrate 11 bearing the metallized layer 12, and the metallized layer 12 covers and fills the anchor connection structure 111; before metal evaporation, the anchor connection structure 111 is pre-prepared on the surface of the film substrate 11 by laser etching or chemical treatment, and during metal evaporation, the metallized layer 12 completely fills these microstructures during deposition to form a firm mechanical interlocking, thereby improving the bonding mechanism from surface physical adsorption to bulk mechanical anchoring.
[0029] Specifically, as shown in the above Figure 4 The anchor connection structure 111 is an array type pit structure regularly arranged on the bonding surface of the anchor connection structure 111; the structure is composed of discrete pits distributed on the bonding surface according to certain rules (such as matrix, hexagonal close packing), each pit is filled with metal material during metal evaporation to form an independent “mechanical rivet point”, and these rivet points are uniformly dispersed and can effectively resist the peeling stress of the metal layer in any direction.
[0030] Specifically, as shown in the above Figure 5The anchoring connection structure 111 is a network of grooves staggered on the bonding surface of the film base 11. The structure is composed of continuous grooves staggered and connected on the bonding surface, forming a network. After the grooves are filled with metal, a continuous "three-dimensional skeleton" type interlocking is formed. This structure not only provides adhesion, but also more effectively prevents and deflects the microcracks that may occur at the interface.
[0031] In summary, in practical applications, the pit array and the network of grooves can be implemented alone or combined on the same bonding surface. For example, the pit array can be further arranged in the area divided by the network of grooves to form a "grid plus dot array" composite anchoring connection structure 111, thereby synergistically improving the bonding strength and reliability at macro and micro scales.
[0032] The above examples are only used to illustrate the technical solutions of the present application, and not to limit them.
Claims
1. A capacitor core, characterized in that: it comprises at least two layers of metallized films (1) arranged in sequence, the metallized film comprising a film substrate (11) and a metallization layer (12) on at least one surface thereof; in the plurality of layers of metallized films (1), at least two adjacent layers of metallized films (1) are arranged in staggered manner in the stacking direction, and the staggered arrangement comprises axial staggering and / or circumferential staggering.
2. The capacitor core of claim 1 wherein, The axial staggering is that in the direction parallel to the winding core axis, the corresponding side edges of the adjacent two layers of metallized films (1) are offset from each other.
3. The capacitor core of claim 1 wherein, The circumferential staggering is that in the projection plane perpendicular to the winding core axis, the metallization layer (12) patterns of the adjacent two layers of metallized films (1) are rotated around the core central axis by an angle.
4. The capacitor core of claim 2 or 3, wherein: When the number of the metallized films (1) is three or more, all the metallized films (1) form alternating odd layers and even layers in the stacking direction, and the metallized films (1) of the odd layers correspond to each other, the metallized films (1) of the even layers correspond to each other, and the metallized films (1) of the odd layers and the metallized films (1) of the even layers are arranged in staggered manner.
5. The capacitor core of claim 1 wherein: The metallization layer (12) has a wave-shaped profile at at least one side edge of its planar pattern.
6. The capacitor core of claim 5 wherein: The wave-shaped profile is wavy or zigzag.
7. The capacitor core of claim 5 wherein: The wave-shaped profile of the metallization layer is located entirely inside the physical edge of the film substrate to form a margin area (13) on the film substrate.
8. The capacitor core of claim 1 wherein: An anchoring connection structure is provided on at least one surface of the film substrate (11) carrying the metallization layer (12), and the metallization layer (12) covers and fills the anchoring connection structure.
9. The capacitor core of claim 8, wherein: The anchoring connection structure is an array of recess structures regularly arranged on the bonding surface of the anchoring connection structure. And / or, the anchoring connection structure is a network of grooves staggered on the bonding surface of the film substrate (11).
10. A metalized film roll-embossed capacitor characterized by: The capacitor core according to any one of claims 1-9.