Ptc protection element and battery pack

Abstract

PTC protection element and battery pack. Provided are: a first PTC chip and a second PTC chip which are stacked; an intermediate pin which is sandwiched between the first PTC chip and the second PTC chip and is electrically connected to both; and a parallel pin which includes an upper pin portion which is attached to an upper surface of the first PTC chip and a lower pin portion which is attached to a lower surface of the second PTC chip, the first PTC chip and the second PTC chip are sandwiched between the upper pin portion and the lower pin portion, and the upper pin portion and the lower pin portion are electrically connected to each other, so that current input to the parallel pin can be converged to the intermediate pin through the first PTC chip and the second PTC chip, respectively.

Description

Technical Field

[0001] This disclosure relates to a PTC protection element and a battery pack incorporating the PTC protection element. Background Technology

[0002] With the rapid development of electric vehicles, energy storage systems, and portable electronic devices, the use of high-energy-density battery packs is becoming increasingly widespread, and their safety issues are becoming more prominent. Overcharging, short circuits, or abnormal heating can all lead to battery thermal runaway and cause serious accidents. PTC protection elements, as an important overcurrent protection component, are widely used in battery packs. When the circuit current abnormally increases, causing the temperature to rise, the resistance of the PTC protection element will rise sharply, thereby limiting the current and acting as a "switch" for protection.

[0003] Existing PTC protection components typically consist of an upper pin, a PTC chip, and a lower pin stacked together. The PTC chip is sandwiched between the upper and lower pins, with the lower surface of the lower pin in contact with the battery electrodes. Current flows from the lower pin through the PTC chip and out through the upper pin. When the current in this circuit abnormally increases, causing the temperature to rise, the resistance of the PTC chip will rise sharply, thereby limiting the current.

[0004] However, the existing PTC protection elements have the following drawbacks: the maximum operating current of existing PTC protection elements is directly related to the area of ​​the PTC chip. Increasing the chip area is limited by the space within the battery pack, and increasing the chip area leads to increased cost and thermal inertia (slower response). Furthermore, the increase in area is not linearly proportional to the increase in maximum operating current. This restricts the maximum operating current that existing PTC protection elements can safely carry, failing to meet the requirements of battery packs developing towards higher capacity and higher discharge rates. Summary of the Invention

[0005] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a PTC protection element and a battery pack using the PTC protection element, which can increase the maximum operating current without increasing the area of ​​the PTC chip.

[0006] The PTC protection element of the first embodiment of the present invention includes: a first PTC chip and a second PTC chip stacked together; an intermediate pin sandwiched between the first PTC chip and the second PTC chip and electrically connected to both; and a parallel pin including an upper pin portion attached to the upper surface of the first PTC chip and a lower pin portion attached to the lower surface of the second PTC chip, wherein the first PTC chip, the intermediate pin, and the second PTC chip are sandwiched between the upper pin portion and the lower pin portion, and the upper pin portion and the lower pin portion are electrically connected to each other, thereby enabling the current input to the parallel pin to converge to the intermediate pin through the first PTC chip and the second PTC chip respectively.

[0007] According to the first aspect of the present invention, the PTC protection element, by stacking a first PTC chip and a second PTC chip and forming a parallel conductive path through which current flows through the first PTC chip and the second PTC chip respectively and converges to the intermediate pin, can increase the maximum operating current without increasing the area of ​​the PTC chip, thereby meeting the higher requirements of high-capacity, high-rate battery packs for overcurrent protection elements. Furthermore, the two PTC chips share the intermediate pin, reducing the amount of pin material used and lowering costs.

[0008] The second aspect of the PTC protection element of the present invention is that, in the first aspect of the PTC protection element, the upper pin portion and the lower pin portion are integrally formed.

[0009] According to the second aspect of the present invention, the PTC protection element reduces the number of independent parts and simplifies the production process because the upper pin portion and the lower pin portion are integrally formed.

[0010] The third-party PTC protection element of the present invention is, in the second-way PTC protection element, wherein the parallel pin is formed by bending a racetrack-shaped metal sheet.

[0011] According to the third-party PTC protection element of the present invention, parallel pins are formed by bending a racetrack-shaped metal sheet. The processing technology is simple and can achieve low cost while ensuring performance.

[0012] The fourth aspect of the PTC protection element of the present invention is as follows: in the second aspect of the PTC protection element, concentric circular holes are formed on the upper pin portion, the first PTC chip, the second PTC chip, and the middle pin, and a cross-shaped shunt groove is formed on the lower pin portion at a position corresponding to the circular holes.

[0013] According to the fourth aspect of the present invention, the PTC protection element has concentric circular holes formed on the upper pin portion, the first PTC chip, the second PTC chip, and the middle pin, and a cross-shaped shunt groove formed on the lower pin portion at a position corresponding to the circular holes. This allows the lower pin portion to be easily soldered to the battery electrode through the circular holes, and the cross-shaped shunt groove improves the soldering strength. At the same time, it makes the metal sheet easier to deform, absorbing the dimensional tolerances of the battery or the PTC disclosed in this invention, forming a reliable solder joint. This allows the PTC element to be placed and soldered at any angle of 0°, 90°, 180°, or 270° without the need to customize different pins for different installation directions, greatly enhancing the flexibility of PTC element layout, reducing mold costs, and shortening the product development cycle.

[0014] The fifth embodiment of the PTC protection element of the present invention further includes a parallel guide plate and an insulating sheet in the PTC protection elements of the first to fourth embodiments. The parallel guide plate and the insulating sheet are sandwiched between the second PTC chip and the lower pin portion. The parallel guide plate is attached to the lower surface of the second PTC chip. The parallel guide plate is electrically connected to the upper pin portion and the lower pin portion at the position where the upper pin portion and the lower pin portion are electrically connected to each other to form a current shunt region. The insulating sheet is sandwiched between the parallel guide plate and the lower pin portion, so that the portion of the parallel guide plate located outside the current shunt region is insulated from the lower pin portion.

[0015] According to the fifth aspect of the present invention, the PTC protection element adds a parallel guide plate and an insulating sheet between the second PTC chip and the lower pin portion, so that the current flowing in from the lower pin portion is diverted to the upper pin portion and the parallel guide plate in a specific shunting area, and then flows through the first PTC chip and the second PTC chip respectively to converge to the middle pin, thereby ensuring the impedance balance of the parallel branch, achieving a better current sharing effect, making the current flowing through the two PTC chips the same, and thus making the operating time of the two PTC chips tend to be the same.

[0016] The PTC protection element of the sixth embodiment of the present invention comprises: a first PTC chip and a second PTC chip stacked together; an intermediate pin sandwiched between the first PTC chip and the second PTC chip and electrically connected to both; a parallel pin including an upper pin portion and a lower pin portion, the upper pin portion and the lower pin portion being separately disposed, the first PTC chip, the intermediate pin, and the second PTC chip being disposed between the upper pin portion and the lower pin portion; a parallel guide plate attached to the lower surface of the second PTC chip; and an insulating sheet sandwiched between the parallel guide plate and the lower pin portion, thereby insulating the parallel guide plate from the lower pin portion. The parallel guide plate, the upper pin portion, and the lower pin portion are respectively connected to a current controller via wires, and the current controller is capable of proportionally outputting the current input from the lower pin portion to the parallel guide plate and the upper pin portion.

[0017] According to the sixth aspect of the present invention, the PTC protection element insulates the parallel guide plate from the lower pin portion through an insulating sheet, and outputs the current input from the lower pin portion to the parallel guide plate and the upper pin portion in proportion through a current controller, thereby enabling more accurate and proactive monitoring and adjustment of the current flowing through the two PTC chips, meeting higher protection accuracy and reliability requirements.

[0018] The PTC protection element of the seventh embodiment of the present invention is as follows: in the PTC protection element of the sixth embodiment, circular holes are formed on the upper pin portion, the first PTC chip, the second PTC chip, the middle pin, the parallel guide plate, and the insulating sheet, and the circular holes are arranged concentrically. A cross-shaped shunt groove is formed on the lower pin portion at the position corresponding to each of the circular holes.

[0019] According to the seventh aspect of the present invention, a PTC protection element has circular holes formed on the upper pin portion, the first PTC chip, the second PTC chip, the middle pin, the parallel guide plate, and the insulating sheet, with each of the circular holes being concentrically arranged. A cross-shaped shunt groove is formed on the lower pin portion at a position corresponding to each of the circular holes. This allows the lower pin portion to be easily soldered to the battery electrode through the circular holes, and the welding strength is improved by the cross-shaped shunt groove. At the same time, it makes the metal sheet easier to deform, absorbing the dimensional tolerances of the battery or the PTC disclosed in this invention, forming a reliable solder joint. This allows the PTC element to be placed and soldered at any angle of 0°, 90°, 180°, or 270° without the need to customize different pins for different installation directions, greatly enhancing the flexibility of PTC element layout, reducing mold costs, and shortening the product development cycle.

[0020] The battery pack of the first embodiment of the present invention includes a plurality of battery cells and a PTC protection element as described in the first to seventh embodiments, wherein the lower pin of the PTC protection element is soldered to the electrode of the battery cell.

[0021] The battery pack according to the first aspect of the present invention can meet the requirements of greater discharge current and safety. Attached Figure Description

[0022] Figure 1 (a) is a drawing showing the state of the PTC protection element of Embodiment 1 of this disclosure installed in a battery cell and in a disassembled state. Figure 1 (b) is a perspective view of the PTC protection element according to Embodiment 1 of this disclosure. Figure 1 (c) is a cross-sectional view of the PTC protection element of Embodiment 1 of this disclosure.

[0023] Figure 2 The accompanying drawing shows the flattened state of the parallel pins in Embodiment 1 of this disclosure.

[0024] Figure 3 The accompanying drawing illustrates the structure of the lower pin in Embodiment 1 of this disclosure.

[0025] Figure 4 (a) is a drawing showing the exploded state of the PTC protection element according to Embodiment 2 of this disclosure. Figure 4 (b) is a perspective view of the PTC protection element of Embodiment 2 of this disclosure.

[0026] Figure 5 (a) is a drawing showing the exploded state of the PTC protection element according to Embodiment 3 of this disclosure. Figure 5 (b) is a perspective view of the PTC protection element of Embodiment 3 of this disclosure.

[0027] Explanation of reference numerals in the attached figures: 100, 100a, 100b: PTC protection components 10, 10a, 10b: First PTC chip 20, 20a, 20b: Second PTC chip 30, 30a, 30b: Intermediate pins 40, 40a, 40b: Parallel pins 41, 41a, 41b: Upper pin section 42, 42a, 42b: Lower pin section 421: Diversion Channel 43a, 43b: Parallel guide plates 50a, 50b: Insulating sheets 70: Current controller Detailed Implementation

[0028] The technical solution of this disclosure will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0029] In all the accompanying drawings, the same reference numerals denote the same elements. Furthermore, the drawings are schematic diagrams illustrating the structures involved in this disclosure, and this disclosure is not limited to the structures shown in the drawings. The terminology used in the specification is only for describing specific embodiments and is not intended to limit this disclosure. All terms used in the specification, unless otherwise defined, have the meaning commonly understood by those skilled in the art. For the sake of brevity and clarity, well-known functions or structures may not be described in detail. In the description of this invention, the term "connection" includes both "direct connection" and "indirect connection," and the terms "upper," "lower," "inner," "outer," etc., indicate orientations or positional relationships based on those shown in the accompanying drawings, or orientations or positional relationships conventionally set when the product of this invention is used. These are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Ordinal numbers such as "first," "second," etc., are only for distinguishing components and do not have any sequential meaning.

[0030] Implementation Method 1 like Figure 1 As shown in (a), (b) and (c), the PTC protection element 100 of this embodiment includes a first PTC chip 10, a second PTC chip 20, an intermediate pin 30 and a parallel pin 40 stacked together.

[0031] like Figure 1 As shown in (a), the first PTC chip 10 and the second PTC chip 20 are formed in a ring shape. The first PTC chip 10 and the second PTC chip 20 are stacked in the vertical direction with concentric circular holes in the ring shape. The first PTC chip 10 is located on top and the second PTC chip 20 is located on the bottom.

[0032] like Figure 1As shown in (a), the intermediate pin 30 is made of a highly conductive metal sheet (such as a nickel sheet, copper sheet, etc.). One end of the intermediate pin 30 is formed into a ring shape and sandwiched between the first PTC chip 10 and the second PTC chip 20. The circular hole of the ring shape is concentric with the circular holes of the first PTC chip 10 and the second PTC chip 20. The upper and lower surfaces of the ring-shaped end of the intermediate pin 30 are connected to the lower surface of the first PTC chip 10 and the upper surface of the second PTC chip 20 by means of conductive adhesive, sintering, or direct pressing. The other end of the intermediate pin 30 is formed into a strip shape and extends from between the first PTC chip 10 and the second PTC chip 20.

[0033] like Figure 2 As shown, the parallel pin 40 is made of a metal sheet, preferably a nickel sheet, a copper-nickel composite sheet, etc.

[0034] In this embodiment, the metal sheet constituting the parallel pin 40 is formed in a racetrack shape. A circular hole is formed at one end of the metal sheet along its length, and a cross-shaped flow divider 421 is formed at the other end along its length. Notches are formed at the center of the two long sides of the metal sheet, allowing the metal sheet to be easily folded to form a bending structure, thereby forming a structure as shown... Figure 1 (c) Upper pin portion 41 and lower pin portion 42. By integrally molding the upper pin portion 41 and lower pin portion 42 in the manner described above, the number of independent parts is reduced, and the production process is simplified. In addition, the parallel pin 40 is formed by bending a racetrack-shaped metal sheet, which simplifies the manufacturing process and enables cost reduction while ensuring performance.

[0035] like Figure 1 and 2 As shown, the upper lead portion 41 is one end of a metal sheet with a circular hole, which is attached to the upper surface of the first PTC chip 10, forming a structure that clamps the first PTC chip 10 together with the middle lead 30. The lower lead portion 42 is one end of a metal sheet with a cross-shaped shunt groove 421, which is attached to the lower surface of the second PTC chip 20, forming a structure that clamps the second PTC chip 20 together with the middle lead 30.

[0036] The upper pin portion 41, the first PTC chip 10, the middle pin 30, and the circular holes formed on the second PTC chip 20 are arranged coaxially, so that the lower pin portion 42 can be soldered to the electrode of the battery cell through these circular holes.

[0037] In this embodiment, a cross-shaped shunt groove 421 is formed on the lower lead portion 42. The position of 421 corresponds to the position of the circular hole formed on the upper lead portion 41, the first PTC chip 10, the middle lead 30, and the second PTC chip 20, so that the lower lead portion 42 can be soldered to the battery electrode through the circular hole. The position of the solder joint is preferably as follows: Figure 3 As shown, the cross-shaped shunt 421 improves the welding strength and makes the metal sheet easy to deform, absorbing the dimensional tolerances of the battery or the PTC disclosed herein, forming a reliable solder joint. This allows the PTC element to be placed and welded at any angle of 0°, 90°, 180°, or 270° without the need to customize different pins for different mounting directions. This greatly enhances the flexibility of PTC element layout, reduces mold costs, and shortens the product development cycle.

[0038] According to the PTC protection element 100 of this embodiment, when current flows into the PTC protection element 100 from the lower pin portion 42 of the parallel pin 40, it splits into two paths. One path flows through the upper pin portion 41 of the parallel pin 40 to the first PTC chip 10 and exits from the middle pin 30. The other path flows through the lower pin portion 42 of the parallel pin 40 to the second PTC chip 20 and exits from the middle pin 30. The middle pin 30 serves as a common current outlet. The upper pin portion 41, the middle pin 30, and the lower pin portion 42 together form an integrated and stable parallel conductive path, thereby increasing the maximum operating current without increasing the area of ​​the PTC chip, thus meeting the higher requirements of high-capacity, high-rate battery packs for overcurrent protection elements. Furthermore, the two PTC chips share the middle pin, reducing the amount of pin material used and lowering costs.

[0039] Implementation Method 2 Next, refer to Figure 4 Embodiment 2 of the present invention will be described.

[0040] like Figure 4 As shown in (a) and (b), the structure of the PTC protection element 100a in Embodiment 2 is similar to that of the PTC protection element 100 in Embodiment 1. It includes a first PTC chip 10a, a second PTC chip 20a, an intermediate pin 30a, and a parallel pin 40a stacked together. The parallel pin 40a includes an upper pin portion 41a and a lower pin portion 42a.

[0041] Compared to the PTC protection element 100 of Embodiment 1, in the PTC protection element 100a of Embodiment 2, an insulating sheet 50a and a parallel guide plate 43a are provided between the lower lead portion 42a and the second PTC chip 20a. The parallel guide plate 43a is formed with the same shape as the lower lead portion 42a, can be made of the same material as the parallel lead 40a, and is attached to the lower surface of the second PTC chip 20a. That is, Embodiment 2 is based on Embodiment 1, by adding a parallel guide plate 43a and an insulating sheet 50a sequentially between the second PTC chip 20a and the lower lead portion 42a.

[0042] like Figure 4 As shown in (a) and (b), the parallel guide plate 43a and the bent area of ​​the parallel pin 40a are electrically connected to form a shunt region. That is, the upper pin 41a, the parallel guide plate 43a, and the lower pin 42a are connected in the shunt region. Thus, the current flowing from the battery through the lower pin 42a to the PTC protection element 100a is divided into two paths in this shunt region. One path flows from the lower pin 42a through the upper pin 41a to the first PTC chip 10a and then out through the middle pin 30a. The other path flows from the lower pin 42a through the parallel guide plate 43a to the second PTC chip 20a and then out through the middle pin 30a. The middle pin 30a serves as a common current outlet. The upper pin 41a, the middle pin 30a, and the parallel guide plate 43a together constitute an integrated and stable parallel conductive path.

[0043] Compared to embodiment 1, embodiment 2 ensures impedance balance of the parallel branch by diverting the current flowing in from the lower pin 42a to the upper pin 41a and the parallel guide plate 43a in a specific shunting region, and then flowing through the first PTC chip 10a and the second PTC chip 20a respectively to converge to the middle pin 30a. This achieves a better current sharing effect, makes the current flowing through the two PTC chips the same, and thus makes the operating time of the two PTC chips similar.

[0044] Implementation Method 3 Next, refer to Figure 5 Embodiment 3 of the present invention will be described.

[0045] like Figure 5 As shown in (a) and (b), the structure of the PTC protection element 100b in Embodiment 3 is similar to that of the PTC protection element 100a in Embodiment 2, including a first PTC chip 10b, a second PTC chip 20b, an intermediate pin 30b, and a parallel pin 40b stacked together. The parallel pin 40b includes an upper pin portion 41b and a lower pin portion 42b. An insulating sheet 50b and a parallel guide plate 43b are disposed between the lower pin portion 42b and the second PTC chip 20b.

[0046] Compared to the PTC protection element 100a in Embodiment 2, in the PTC protection element 100b in Embodiment 3, the upper pin portion 41b, the parallel guide plate 43b, and the lower pin portion 42b are not directly connected to each other in the shunt region, but are respectively connected to the current controller 70 via wires. The current controller 70 can be a microprocessor-based active balancing circuit or intelligent switching circuit, having one input terminal INPUT and two independent output terminals OUTPUT 1 and OUTPUT 2. The input terminal is connected to the lower pin portion 42b via a wire, and the two output terminals are respectively connected to the upper pin portion 41b and the parallel guide plate 43b of the PTC protection element 100b via wires.

[0047] By configuring the PTC protection element 100b of Embodiment 3 as described above, the current flowing out of the battery flows into the current controller 70 through the lower pin 42b. The current controller 70 divides the current into two paths: one path flows through the upper pin 41b to the first PTC chip 10b and then flows out from the middle pin 30b; the other path flows through the parallel guide plate 43b to the second PTC chip 20b and then flows out from the middle pin 30b.

[0048] Since the current controller 70 can control the current flowing through the two branches in real time and control the ratio of the current flowing to the first PTC chip 10b and the second PTC chip 20b, the current distribution can always be in the optimal state, which can meet the requirements of higher protection accuracy and reliability, and even pre-adjust before the PTC protection element operates, so as to realize intelligent overcurrent protection.

[0049] The embodiments of the PTC protection element of the present invention have been described above. Next, the structure of a battery pack using the PTC protection element of the present invention will be described.

[0050] A battery pack using the PTC protection element of this invention comprises multiple battery cells. The PTC protection element of this invention can be connected to the positive terminal or the negative terminal of a battery cell. Assembling multiple battery cells with the PTC protection element disclosed herein yields a battery pack. During assembly, the lower lead of the PTC protection element is soldered to the electrode of the battery cell or to accessories such as a busbar or protection board electrically connected to the battery cell. The PTC protection element of this invention has a compact structure and reliable connection, making it ideal for use in space-constrained battery packs.

[0051] The PTC protection element and the battery pack equipped with the PTC protection element of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. Therefore, it should be understood that the present invention includes changes and modifications within the scope of the appended claims and their equivalents. In particular, it should be understood that any combination of any part or all of any two or more of the above embodiments and their modifications is within the scope of the present invention.

[0052] Industrial applicability This disclosure can be applied to the production and use of PTC protection elements and battery packs equipped with such PTC protection elements.

Claims

1. A PTC protection element, characterized in that, have: A first PTC chip and a second PTC chip are stacked together; The intermediate pin is sandwiched between the first PTC chip and the second PTC chip, and is electrically connected to both of them respectively; and The parallel pin includes an upper pin portion and a lower pin portion, with the first PTC chip, the intermediate pin, and the second PTC chip sandwiched between the upper pin portion and the lower pin portion. The upper pin portion and the lower pin portion are electrically connected to each other, thereby enabling the current input to the parallel pin to flow to the intermediate pin through the first PTC chip and the second PTC chip respectively.

2. The PTC protection element according to claim 1, characterized in that, The upper pin portion and the lower pin portion are integrally formed.

3. The PTC protection element according to claim 2, characterized in that, The parallel pins are formed by bending a racetrack-shaped metal sheet.

4. The PTC protection element according to claim 2, characterized in that, Circular holes are formed on the upper pin portion, the first PTC chip, the second PTC chip, and the middle pin, respectively, and the circular holes are arranged concentrically. A cross-shaped shunt groove is formed on the lower pin portion at the position corresponding to each of the circular holes.

5. The PTC protection element according to any one of claims 1-4, characterized in that, It also includes a parallel guide plate and an insulating sheet, which are sandwiched between the second PTC chip and the lower pin portion. The parallel guide plate is attached to the lower surface of the second PTC chip. The parallel guide plate is electrically connected to the upper pin portion and the lower pin portion at the position where the upper pin portion and the lower pin portion are electrically connected to each other to form a current shunt region. The insulating sheet is sandwiched between the parallel guide plate and the lower pin portion, so that the portion of the parallel guide plate located outside the current shunt region is insulated from the lower pin portion.

6. A PTC protection element, characterized in that, have: A first PTC chip and a second PTC chip are stacked together; The middle pin is sandwiched between the first PTC chip and the second PTC chip, and is electrically connected to both of them respectively; The parallel pin includes an upper pin portion and a lower pin portion, the upper pin portion and the lower pin portion are separately disposed, and the first PTC chip, the intermediate pin and the second PTC chip are disposed between the upper pin portion and the lower pin portion; A parallel guide plate is attached to the lower surface of the second PTC chip; as well as An insulating sheet is sandwiched between the parallel guide plate and the lower lead portion to insulate the parallel guide plate from the lower lead portion. The parallel guide plate, the upper pin portion, and the lower pin portion are respectively connected to the current controller via wires. The current controller can output the current input from the lower pin portion to the parallel guide plate and the upper pin portion in a proportional manner.

7. The PTC protection element as described in claim 6, characterized in that, Circular holes are formed on the upper pin portion, the first PTC chip, the second PTC chip, the middle pin, the parallel guide plate, and the insulating sheet, respectively, and the circular holes are arranged concentrically. A cross-shaped shunt groove is formed on the lower pin portion at the position corresponding to each of the circular holes.

8. A battery pack, characterized in that, include: Multiple battery cells; as well as The PTC protection element according to any one of claims 1-7, wherein the lower pin portion of the PTC protection element is soldered to the electrode of the battery cell.

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