阅读说明：本技术 一种适用于贴装过流保护器件ptc的保护板 (Protection plate suitable for pasting and mounting over-current protection device PTC ) 是由 夏坤 方勇 张锐 黄定兵 曹清华 张伟 吴国臣 于 2019-09-26 设计创作，主要内容包括：本发明涉及一种适用于贴装过流保护器件PTC的保护板,是硬板、软板、软硬结合板,包括基板层和线路层,线路层覆于基板层表面,所述的线路层包含焊接各电子元器件引脚的焊盘、构成线路的导电线和覆盖导电线的保护层,其中,至少包含1组用于焊接PTC的焊盘,导电线在走线时至少有1根从焊接PTC两端引脚的焊盘中间进行局部布线或是从两端引脚的焊盘之间穿过,即至少1根导电线从PTC的底部经过。本发明通过导电线走线时从PTC的底部经过的设计,当电流较小时,该段导电线发热较小,PTC几乎不受该段导电线的发热影响,当电流较大时,该段导电线发热剧增,PTC受该段导电线的发热影响较大,更容易触发PTC的动作保护。(The invention relates to a protection board suitable for mounting an overcurrent protection device PTC, which is a hard board, a soft board and a soft and hard combined board and comprises a substrate layer and a line layer, wherein the line layer covers the surface of the substrate layer, and comprises bonding pads for welding pins of electronic components, conducting wires for forming a line and a protection layer for covering the conducting wires, wherein at least 1 group of bonding pads for welding the PTC are included, and at least 1 conducting wire is locally wired from the middle of the bonding pads for welding the pins at two ends of the PTC or penetrates through the bonding pads for welding the pins at two ends when in wiring, namely at least 1 conducting wire passes through the bottom of the PTC. According to the invention, through the design that the conductive wire passes through the bottom of the PTC when the wire is wired, when the current is small, the conductive wire generates less heat, the PTC is hardly influenced by the heat of the conductive wire, when the current is large, the conductive wire generates heat sharply, the PTC is greatly influenced by the heat of the conductive wire, and the action protection of the PTC is more easily triggered.)

1. The protection board comprises a substrate layer and a line layer, wherein the line layer covers the surface of the substrate layer, and the protection board is characterized in that the line layer comprises bonding pads for welding pins of all electronic components, conductive wires forming a line and a protection layer for covering the conductive wires, wherein at least 1 group of bonding pads for welding the PTC are included, and at least 1 conductive wire is locally wired in the middle of the bonding pads for welding the pins at two ends of the PTC or penetrates through the bonding pads for welding the pins at two ends when in wiring, namely at least 1 conductive wire passes through the bottom of the PTC.

2. The protection plate for attaching an overcurrent protection device PTC according to claim 1, wherein the conductive wire passes through the bottom of the PTC and can be a single-side all-through type, a double-side all-through type, a single-side partial wiring type, a double-side partial wiring type, or a single-side partial wiring type and a full-through type.

3. A protection plate suitable for being mounted with a PTC of an overcurrent protection device according to claim 1 or 2, wherein the conducting wires passing through the bottom of the PTC can be single, double or more or all.

4. A protection plate suitable for being mounted with an overcurrent protection device PTC according to claim 3, wherein the conductive wire trace is a straight line, a curved line, or a combination of a straight line and a curved line.

5. A protective plate suitable for mounting an overcurrent protection device PTC according to claim 1 or 2, wherein the circuit layer further comprises bonding pads for soldering NTC, IC, MOS, precision resistor, capacitor type electronic components and conductive wires for forming electronic circuits.

6. The protection plate suitable for being mounted with an overcurrent protection device PTC according to claim 5, wherein the shape of the bonding pad can be round, rectangular, polygonal or irregular, and the surface treatment mode of the bonding pad can be one or more than two of electroless nickel gold, electroplating nickel gold, electroless silver, OSP and hot air leveling.

7. A protection plate suitable for mounting an over-current protection device PTC according to claim 5, wherein said wiring layer is single layer, double layer or multi-layer, and when the wiring layer is double layer or multi-layer, the circuit is connected through the conductive hole between the wiring layers.

8. The protection plate suitable for being mounted with an over-current protection device PTC according to claim 7, wherein the conductive hole is one or a combination of more than two of a through hole, a blind hole and a buried hole.

9. The protection plate suitable for being mounted with a PTC of an overcurrent protection device according to claim 1, wherein the substrate layer is a layer of phenolic resin, epoxy resin, polyester resin, BT resin, PI resin, PPO resin, MS resin, ceramic, metal or metal alloy.

10. The protection plate for mounting a PTC of an overcurrent protection device according to claim 1 or 6, wherein the number of the substrate layers can be a single layer, a double layer or a multi-layer.

11. The protective plate for attaching an overcurrent protection device PTC according to claim 1, wherein the protective layer exposes the bonding pad window.

12. A protection plate suitable for being mounted with an overcurrent protection device PTC according to claim 1 or 11, wherein a nickel layer is formed on the surface of the bonding pad by chemical nickel-gold deposition.

13. The protection plate suitable for being attached with the over-current protection device PTC according to claim 1 or 11, wherein the protection layer is solder resist ink covering the surface of the circuit layer and silk-screen characters printed on the solder resist ink.

Technical Field

The invention relates to a protection plate which can ensure long-term use of PTC under the condition of common low current application and can meet the requirement that the protection action time of a Limited Power Supply (LPS for short) 8A is within 60s, wherein a wire is designed to pass through a bonding pad for welding pins at two ends of the PTC, namely to pass through the bottom of the PTC, and when low current is passed, the conductive wire generates little heat and hardly affects the PTC; when a large current is conducted, the conductive wire section generates heat greatly, so that the heat generation of the PTC is accelerated, and the PTC is easier to act and protect.

Background

Along with the increasingly strict requirements of users on products such as smart phones, the capacity of a battery core of the smart phone is increased, the charging current of the smart phone is increased, the popularity of quick charging has higher and higher requirements on a PTC (positive temperature coefficient) of an overcurrent protection device, and the quick charging is expected to reduce the initial resistance, improve the sustainable current and prolong the service life of the PTC; however, the reduction of resistance inevitably causes a delay in the PTC operation time, and the protection operation time required by LPS for PTC is 8A to less than 60s in the case of using a PTC overcurrent protection device according to the standard specification for LPS in lithium battery safety standard UL 2054. Therefore, it is likely that PTC alone cannot satisfy both the low resistance and LPS.

Disclosure of Invention

The invention aims to: the protection plate is suitable for mounting the PTC of the over-current protection device, so that the PTC can simultaneously meet the LPS standard specified by the battery safety standard UL2054 while meeting low resistance and long service life.

The purpose of the invention is realized by the following technical scheme: the invention provides a protection board suitable for mounting a PTC (positive temperature coefficient) of an overcurrent protection device, which can be a hard board, a soft board and a rigid-flexible board and comprises a substrate layer and a line layer, wherein the line layer covers the surface of the substrate layer, and comprises bonding pads for welding pins of electronic components, conducting wires forming a line and a protection layer for covering the conducting wires, wherein at least 1 group of bonding pads for welding the PTC are included, and at least 1 conducting wire is locally wired from the middle of the bonding pads for welding the pins at two ends of the PTC or is penetrated between the bonding pads for welding the pins at two ends when in wiring, namely at least 1 conducting wire passes through the bottom of the PTC.

The conductive wires of the circuit layer of the invention have 1 or more than 2 conductive wires which are locally wired from the middle of the welding pads of the welding PTC or pass through the welding pads of the welding PTC, namely, part or all of the conductive wires pass through the bottom of the PTC. The principle is as follows: when the power is switched on in the circuit, the heat generated by the section from the bottom of the PTC through the conductive wire can help to accelerate the heat generation of the PTC according to the heat generation power Q = I²And R, when the current is small, the conductive wire generates less heat, the PTC is hardly influenced by the heat of the conductive wire, when the current is large, the conductive wire generates heat and increases sharply, and the PTC is greatly influenced by the heat of the conductive wire, so that the action protection of the PTC is triggered more easily.

The type of the conductive wire passing through the bottom of the PTC element can be a single-side all-through type, a double-side all-through type, a single-side local wiring type, a double-side local wiring type, or a local wiring type and a full-through type.

The conductive wires passing through the bottom of the PTC may be single, double or more, or all.

The conducting wire routing is a straight line, a curve or a combination of the straight line and the curve.

The circuit layer also comprises a bonding pad for welding NTC, IC, MOS, precision resistor and capacitor electronic components and a conducting wire for forming an electronic circuit.

The shape of the bonding pad can be round, rectangular, polygonal and irregular, and the surface treatment mode of the bonding pad can be one or more than two of chemical precipitation nickel gold, electroplating nickel gold, chemical precipitation silver, OSP and hot air leveling.

The circuit layer can be a single layer, a double layer or a multilayer, and when the circuit layer is a double layer or a multilayer, the circuit layer is connected with a circuit through a conductive hole between the circuit layers.

And one or the combination of more than two of the conductive hole through hole, the blind hole and the buried hole.

The substrate layer is a phenolic resin, an epoxy resin, a polyester resin, a BT resin, a PI resin, a PPO resin, an MS resin, a ceramic, a metal or a metal alloy layer.

On the basis of the scheme, the number of the substrate layers can be single layer, double layers or multiple layers.

The surface of the circuit layer needs to be printed with a protective layer, so that the circuit layer is protected, the short circuit of the solder in dip-dyeing of the non-pad part is prevented, and meanwhile, the pad for welding the pins of the electronic components needs to be windowed and exposed.

The protective layer is solder resist ink covering the surface of the circuit layer and silk-screen characters printed on the solder resist ink.

The invention has the advantages that: the protection shield changes the ambient temperature around the PTC through the design of walking the line and influences the heating of PTC, passes between the pad of welding PTC both ends pin when walking the line, namely passes through from the bottom of PTC. When the access circuit is electrified, the heat of the conductive wire can help to accelerate the heat generation of the PTC, and the Q = I heat generation power²And R, when the current is small, the conductive wire generates less heat, the PTC is hardly influenced by the heat of the conductive wire, when the current is large, the conductive wire generates heat and increases sharply, and the PTC is greatly influenced by the heat of the conductive wire, so that the action protection of the PTC is triggered more easily. The PTC can realize low resistance and long service life and can meet the standard of LPS.

Drawings

FIG. 1 is a cross-sectional view of a test plate according to example 1 of the present invention;

FIG. 2 is a schematic structural diagram of a test board according to embodiment 1 of the present invention;

FIG. 3 is a schematic structural diagram of a test board according to example 2 of the present invention;

FIG. 4 is a schematic structural diagram of a test board according to example 3 of the present invention;

FIG. 5 is a schematic view of a test board according to example 4 of the present invention;

FIG. 6 is a schematic structural view of a conventional test board not incorporating the present invention;

FIG. 7 shows an action time of 8A, wherein from left to right, the conventional testboard, the single-sided all-pass type, the double-sided all-pass type, the single-sided local layout, and the double-sided local layout are shown;

fig. 8 is a curve showing the change in charge/discharge resistance of 3A, in which the right side is a full-double-side-penetration type, a partial-double-side-wiring type, a full-single-side-penetration type, a partial-single-side-wiring type, or a conventional test board, respectively, from top to bottom;

the reference numbers in the figures illustrate:

1-protective layer;

2-line layer;

3-the substrate layer;

4-a nickel-gold layer;

5——PTC；

21a — a first test pad; 21 b-second test pad;

22 a-first PTC pad; 22 b-second PTC pad;

23a — first electrically conductive line of example 1; 23b — second conductive line of example 1;

23c — first electrically conductive line of example 2; 23d — second conductive line of example 2;

23e — first electrically conductive line of example 3; 23f — second conductive line of example 3;

23g — first electrically conductive line of example 4; 23h — example 4 second conductive line;

23i — conventional test board first conductive line; 23j — conventional test board second conductive line.

Detailed Description