CN213459900U

CN213459900U - Battery cover plate assembly and single battery

Info

Publication number: CN213459900U
Application number: CN202022275774.9U
Authority: CN
Inventors: 陈代松; 喻聪; 冷利民; 徐中领; 张耀
Original assignee: Sunwoda Electric Vehicle Battery Co Ltd
Current assignee: Xinwangda Power Technology Co ltd
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2021-06-15
Anticipated expiration: 2030-10-14

Abstract

The utility model relates to a battery cover plate component and a single battery, wherein, the battery cover plate component comprises a current conducting plate, a positive terminal, a negative terminal and a composite safety component; the composite safety assembly is connected between the upper surface of the conductive plate and the negative terminal in series; the composite safety assembly comprises a memory alloy piece and a current limiting element, wherein the memory alloy piece and the current limiting element can be connected in series with each other, the memory alloy piece is used for being converted from a compression state to an extension state when the temperature is increased to a first temperature so as to conduct a negative terminal and a conductive plate, so that the battery forms an external short circuit, and the current limiting element is used for limiting short-circuit current; when the temperature is lower than the first temperature, the memory alloy piece is in a compressed state, and the negative terminal and the conductive plate are separated and insulated. The battery cover plate component and the single battery of the utility model do not need to add gas production additives such as lithium carbonate and the like in the battery pole piece, thereby not influencing the cycle and storage performance of the battery; in addition, the current limiting element is arranged in the composite safety component, so that short-circuit discharge current can be effectively limited.

Description

Battery cover plate assembly and single battery

Technical Field

The utility model relates to a battery technology field especially relates to a battery cover plate subassembly and battery cell.

Background

Along with the popularization of automobile electromotion, the endurance mileage of the electric automobile is continuously improved, the energy density of a power battery is higher and higher, and the accidents of electric automobile fire caused by overcharging and overheating are more frequent. If the energy of the battery cannot be timely and controllably released, worse accidents are possibly caused.

At present, a mechanical turnover piece or a similar device is arranged on a common power battery cover plate, so that the anode and the cathode of the battery are in short circuit when overcharged and overheated, and the energy of the battery is released through external short circuit to play a role in protection. In order to normally turn the turnover sheet, a certain amount of lithium carbonate is generally required to be added into the positive electrode of the battery, and the lithium carbonate is decomposed to generate a large amount of gas when the battery reaches the decomposition voltage or temperature, or an overcharge additive such as biphenyl is added into the electrolyte, and when the battery is overcharged to a certain voltage or temperature, the biphenyl is subjected to polymerization reaction to generate a large amount of gas, so that the gas pressure in the battery is increased, and the turnover sheet is turned over. The addition of additives such as lithium carbonate or biphenyl not only reduces the energy density of the whole battery core, but also has great negative effects on the cycle and storage performance of the battery.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a battery cover plate assembly and a single battery to solve the above problems.

The utility model discloses a battery cover plate component, which comprises a current conducting plate, a positive terminal, a negative terminal and a composite safety component; the positive terminal can be electrically connected with a positive electrode lug of the battery cell, and the negative terminal can be electrically connected with a negative electrode lug of the battery cell; the positive terminal is electrically connected above the conductive plate, and the composite safety assembly is connected between the upper surface of the conductive plate and the negative terminal in series; the composite safety assembly comprises a memory alloy piece and a current limiting element, wherein the memory alloy piece and the current limiting element can be mutually connected in series, the memory alloy piece is used for being converted from a compression state to an extension state when the temperature is increased to a first temperature so as to conduct a negative terminal and a conductive plate to enable the battery to form an external short circuit, and the current limiting element is used for limiting short-circuit current; when the temperature is lower than a first temperature, the memory alloy piece is in a compressed state, and a gap is reserved between the negative terminal and the conductive plate and is insulated; when the memory alloy member is transformed into the expanded state, the gap disappears and the negative terminal is conducted with the conductive plate.

In one embodiment, the memory alloy member is at least one or a combination of Au-Cd, Ag-Cd, Cu-Zn-M (M ═ Al, Sn, Si, Ga, Au), In-Ti, Ni-Al, Fe-Pt, Ti-Ni-Pd, Ti-Nb, U-Nb, Fe-Mn-Si; the first temperature is in the range of 40 ℃ to 80 ℃.

In one embodiment, the memory alloy member has a two-way shape memory effect, and when the temperature is reduced below the first temperature, the memory alloy member returns from the expanded state to the compressed state so as to restore the spaced and insulated state between the negative terminal and the conductive plate.

In one embodiment, the current limiting element is a fixed resistance element or a PTC element; the resistance range of the constant value resistance element is 1 x 10^-3Ω-1*10³Omega; the PTC element has a resistance suddenly increased at a second temperature to limit short-circuit current, the second temperature is higher than the first temperature, and after the resistance suddenly increased, the resistance of the PTC element ranges from 1 x 10^-3Ω-1*10³Ω。

In one embodiment, the second temperature ranges from 70 ℃ to 150 ℃.

In one embodiment, the composite safety assembly includes an inner element and an outer element, the inner element including the memory alloy element and a flow restriction element; the external element comprises an upper conducting strip, a lower conducting strip and an insulating sealing ring, a mounting hole is formed in the insulating sealing ring, and the upper conducting strip is arranged above the mounting hole and is electrically connected with the negative terminal; the lower conducting plate is arranged below the mounting hole and is electrically connected with the conducting plate; the internal element is arranged in the mounting hole, and one end of the internal element is fixedly connected with the upper conducting strip or the lower conducting strip.

In one embodiment, the upper surface of the insulating seal ring is provided with a first groove, the first groove is communicated with the mounting hole, the upper conducting strip is embedded in the first groove, and the upper surface of the upper conducting strip protrudes out of the upper surface of the insulating seal ring; the lower surface of the insulating sealing ring is provided with a second groove, the second groove is communicated with the mounting hole, the lower conducting strip is embedded in the second groove, and the lower surface of the lower conducting strip protrudes out of the lower surface of the insulating sealing ring.

In one embodiment, the battery cover plate assembly further comprises an insulating gasket, a positive post, a negative post and an insulating sealing plug; the insulating gasket is arranged between the current conducting plate and the negative terminal, a first conducting hole and a second conducting hole which are mutually spaced are formed in the current conducting plate, a third conducting hole and a fourth conducting hole which are mutually spaced are formed in the insulating gasket, the composite safety component is arranged in the fourth conducting hole, and the positive pole is arranged in the first conducting hole in a penetrating mode and used for electrically connecting a positive pole lug and a positive terminal of the battery cell; the positions of the second via hole and the third via hole correspond to each other, and the negative pole column sequentially penetrates through the second via hole and the third via hole and is used for electrically connecting a negative pole lug of the battery cell with a negative pole terminal; the insulating sealing plug is arranged between the hole wall of the current-conducting plate and the positive pole column and the negative pole column in a sealing mode.

In one embodiment, the memory alloy member is in a zigzag folded sheet shape; one end of the current limiting element is fixedly and electrically connected with one of the conductive plate and the negative terminal, the other end of the current limiting element is fixedly and electrically connected with the memory alloy piece, when the memory alloy piece is in a compressed state, a gap is formed between the other end of the memory alloy piece and the other one of the conductive plate and the negative terminal, and when the memory alloy piece is in an extended state, the other end of the memory alloy piece is in contact with the other one of the conductive plate and the negative terminal so as to eliminate the gap and conduct the negative terminal and the conductive plate; or one end of the current-limiting element is fixedly and electrically connected with one of the conductive plate and the negative terminal, one end of the memory alloy piece is fixedly and electrically connected with the other one of the conductive plate and the negative terminal, when the memory alloy piece is in a compressed state, a gap is formed between the other end of the memory alloy piece and the other end of the current-limiting element, and when the memory alloy piece is in an extended state, the other end of the memory alloy piece is in contact with the other end of the current-limiting element so as to eliminate the gap and conduct the negative terminal and the conductive plate; or, the current limiting element comprises a first resistance element and a second resistance element, the first resistance element is a PTC element or a constant value resistance element, the second resistance element is a PTC element or a constant value resistance element, the PTC element is used for increasing resistance suddenly at a second temperature so as to limit short-circuit current, and the second temperature is higher than the first temperature; one end of the first resistance piece is fixedly and electrically connected with one of the conductive plate and the negative terminal, and the other end of the first resistance piece is fixedly and electrically connected with one end of the memory alloy piece; one end of the second resistance piece is fixedly and electrically connected with the other one of the conductive plate and the negative terminal, when the memory alloy piece is in a compressed state, a gap is formed between the other end of the memory alloy piece and the other end of the second resistance piece, and when the memory alloy piece is in an extended state, the other end of the memory alloy piece is in contact with the other end of the second resistance piece, so that the gap is eliminated, and the negative terminal is conducted with the conductive plate.

The utility model also provides a single battery, including electric core, insulating film, casing and any one of the above-mentioned battery cover plate subassembly, be provided with anodal utmost point ear and negative pole utmost point ear on the electric core, anodal utmost point ear is used for being connected with the positive terminal electricity, negative pole utmost point ear is used for being connected with the negative terminal electricity; the insulation film is coated outside the battery core, the battery core and the insulation film are arranged in the shell, an opening is formed in the upper portion of the shell, and the battery cover plate assembly is covered on the opening of the shell.

The utility model discloses a battery cover plate subassembly and battery cell, its beneficial effect is:

the battery cover plate component and the single battery of the utility model have the advantages that the composite safety component is connected between the negative terminal and the current conducting plate in series, and gas generating additives such as lithium carbonate and the like do not need to be added into the battery pole piece, so that the circulation and storage performance of the battery are not influenced; in addition, the current limiting element is arranged in the composite safety assembly, so that short-circuit discharge current can be effectively limited, and the risk of electric core fire and explosion caused by continuous rise of the temperature of the battery is avoided.

Drawings

Fig. 1 is a schematic structural diagram of a single battery according to an embodiment of the present invention.

Fig. 2 is an exploded schematic view of a battery cover plate assembly according to an embodiment of the present invention.

Fig. 3 is a schematic perspective view of a composite safety assembly according to an embodiment of the present invention.

Fig. 4 is an exploded schematic view of a composite safety assembly according to an embodiment of the present invention.

Fig. 5 is a longitudinal cross-sectional view of a memory alloy member in a composite safety assembly in a compressed state according to an embodiment of the present invention.

Fig. 6 is a longitudinal cross-sectional view of a memory alloy member in a composite safety assembly in an extended state according to an embodiment of the present invention.

Fig. 7 is a partial longitudinal cross-sectional view of the composite safety assembly disposed in the fourth via hole of the insulating spacer according to an embodiment of the present invention.

Fig. 8 is a longitudinal cross-sectional view of a memory alloy member in a composite safety assembly according to another embodiment of the present invention in a compressed state.

Fig. 9 is a longitudinal cross-sectional view of a memory alloy member in a composite safety assembly according to another embodiment of the present invention in a compressed state.

Fig. 10 is a longitudinal cross-sectional view of a memory alloy member in a composite security assembly according to yet another embodiment of the present invention in a compressed state.

Fig. 11 is a partial longitudinal cross-sectional view of a composite safety assembly disposed in a fourth via hole of an insulating gasket according to another embodiment of the present invention.

Reference numerals:

the battery comprises a single battery 10, a battery core 100, a positive electrode tab 110, a negative electrode tab 120, an insulating film 200, a shell 300, a battery cover plate assembly 400, a conductive plate 410, a first via hole 411, a second via hole 412, a positive electrode terminal 421, a negative electrode terminal 422, an insulating gasket 430, a third via hole 431, a fourth via hole 432, an insulating plate 440, a fifth via hole 441, a sixth via hole 442, a positive electrode column 451, a negative electrode column 452, an insulating sealing plug 460, a resistor sheet 470, a seventh via hole 471, a positive electrode adapter 481 and a negative electrode adapter 482;

the composite safety assembly 500, an internal element 510, a memory alloy piece 511, a current limiting element 512, a first resistance piece 513, a second resistance piece 514, an external element 520, an upper conductive piece 521, a lower conductive piece 522, an insulating sealing ring 523, a mounting hole 524, a first groove 525, a second groove 526, a first protruding end 531, a second protruding end 532, a first embedding groove 533, and a second embedding groove 534; interval 600.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The utility model provides a battery cover plate subassembly and battery cell, wherein, in an embodiment, the structure of battery cell 10 is as shown in figure 1, including electric core 100, insulating film 200, casing 300 and battery cover plate subassembly 400, be provided with anodal utmost point ear 110 and negative pole utmost point ear 120 on electric core 100, anodal utmost point ear 110 is used for being connected with the anodal terminal 421 electricity on the battery cover plate subassembly 400, negative pole utmost point ear 120 is used for being connected with the negative pole terminal 422 electricity on the battery cover plate subassembly 400; the battery cell 100 and the insulating film 200 are both disposed in the casing 300, and the insulating film 200 is coated outside the battery cell 100, so as to prevent the battery cell 100 from being short-circuited due to direct contact with the inner wall of the casing 300. In addition, as shown in fig. 1, the upper portion of the housing 300 is opened, and the battery cover assembly 400 is covered at the opening of the housing 300.

In one embodiment, the explosion structure of the battery cover plate assembly 400 is shown in fig. 2 and includes a conductive plate 410, a positive terminal 421, a negative terminal 422, an insulating gasket 430, a composite safety assembly 500, an insulating plate 440, a positive post 451, a negative post 452, and an insulating sealing plug 460. Positive terminal 421 is electrically connected to the upper side of conductive plate 410, and resistor disc 470 is also connected in series between positive terminal 421 and conductive plate 410. The insulating plate 440 is disposed under the conductive plate 410 to prevent the battery cell 100 from contacting the conductive plate 410 to be short-circuited. The insulating spacer 430 is disposed between the conductive plate 410 and the negative terminal 422, the conductive plate 410 is formed with a first via hole 411 and a second via hole 412 spaced apart from each other, the insulating spacer 430 is formed with a third via hole 431 and a fourth via hole 432 spaced apart from each other, the insulating plate 440 is formed with a fifth via hole 441 and a sixth via hole 442 spaced apart from each other, and the resistor 470 is formed with a seventh via hole 471. The composite safety component 500 is disposed within the fourth via 432. The positions of the first via hole 411, the fifth via hole 441 and the seventh via hole 471 are corresponding, and the positive post 451 is sequentially inserted into the fifth via hole 441, the first via hole 411 and the seventh via hole 471 to electrically connect the positive tab 110 of the battery cell 100 and the positive terminal 421; the positions of the second via hole 412, the third via hole 431 and the sixth via hole 442 correspond, and the negative pole 452 sequentially penetrates through the sixth via hole 442, the second via hole 412 and the third via hole 431 to electrically connect the negative pole tab 120 of the battery cell 100 and the negative pole terminal 422; the insulating sealing plug 460 is hermetically arranged between the hole wall of the conductive plate 410 and the positive post 451 and the negative post 452, so as to prevent the positive post 451 and the negative post 452 from directly contacting the conductive plate 410 to cause short circuit. In addition, the insulating sealing plug 460 also serves to seal the gaps between the first via hole 411 and the positive post 451, and between the second via hole 412 and the negative post 452.

In a specific embodiment, as shown in fig. 2, the battery cover plate assembly 400 further includes a positive electrode adapter plate 481 and a negative electrode adapter plate 482, wherein the positive electrode adapter plate 481 is used for electrically connecting the positive electrode tab 110 of the battery cell 100 and the positive electrode column 451, and the negative electrode adapter plate 482 is used for electrically connecting the negative electrode tab 120 of the battery cell 100 and the negative electrode column 452. Specifically, the positive electrode tab 110 of the battery cell 100 is welded and fixed to one surface of the positive electrode adaptor 481 (not shown in the drawings), one end of the positive electrode post 451 is welded and fixed to the other surface of the positive electrode adaptor 481, and the other end of the positive electrode post 451 passes through the fifth via hole 441, the first via hole 411 and the seventh via hole 471 in sequence to be electrically connected to the positive electrode terminal 421. The negative electrode tab 120 of the battery cell 100 is welded and fixed to one surface of the negative electrode adaptor 482 (not shown in the drawings), one end of the negative electrode pillar 452 is welded and fixed to the other surface of the negative electrode adaptor 482, and the other end of the negative electrode pillar 452 sequentially passes through the sixth via hole 442, the second via hole 412, and the third via hole 431 to be electrically connected to the negative electrode terminal 422. Note that the resistor sheet 470 connected in series between the positive electrode terminal 421 and the conductive plate 410 is used to reduce a short-circuit current when the short circuit occurs outside the battery, and in other embodiments, the resistor sheet 470 may be omitted.

In one embodiment, the structure of the composite security device 500 is as shown in fig. 3 to 6, where fig. 3 is a perspective view of the composite security device 500, fig. 4 is an exploded view of the composite security device 500, fig. 5 is a longitudinal sectional view of the memory alloy 511 of the composite security device 500 in a compressed state, and fig. 6 is a longitudinal sectional view of the memory alloy 511 of the composite security device 500 in an extended state. The structure in which the composite safety device 500 is disposed in the fourth via hole 432 of the insulating gasket 430 is shown in fig. 7, and the composite safety device 500 is connected in series between the upper surface of the conductive plate 410 and the negative terminal 422. As shown in fig. 3 to 7, the composite safety assembly 500 includes an inner element 510 and an outer element 520, the inner element 510 including a memory alloy element 511 and a current limiting element 512 connected in series with each other; the external element 520 comprises an upper conducting strip 521, a lower conducting strip 522 and an insulating sealing ring 523, wherein a mounting hole 524 is formed in the insulating sealing ring 523, and the upper conducting strip 521 is arranged above the mounting hole 524 and is electrically connected with the negative terminal 422; the lower conductive plate 522 is disposed below the mounting hole 524 and is electrically connected to the conductive plate 410; the inner member 510 is disposed in the mounting hole 524, and one end of the inner member 510 is fixedly connected to the upper conductive plate 521 or the lower conductive plate 522.

In addition, as shown in fig. 3 to 7, the upper surface of the insulating seal ring 523 is provided with a first groove 525, the first groove 525 is communicated with the mounting hole 524, the upper conducting strip 521 is embedded in the first groove 525, and the upper surface of the upper conducting strip 521 protrudes out of the upper surface of the insulating seal ring 523 to form a first protruding end 531; the lower surface of the insulating seal ring 523 is provided with a second groove 526, the second groove 526 is communicated with the mounting hole 524, the lower conducting strip 522 is embedded in the second groove 526, and the lower surface of the lower conducting strip 522 protrudes out of the lower surface of the insulating seal ring 523 to form a second protruding end 532. As shown in fig. 7, the lower surface of the negative terminal 422 is provided with a first embedding groove 533 corresponding to the first protruding end 531, the first protruding end 531 can be embedded in the first embedding groove 533, the upper surface of the conductive plate 410 is provided with a second embedding groove 534 corresponding to the second protruding end 532, and the second protruding end 532 can be embedded in the second embedding groove 534. The structure of the composite safety assembly 500 thus designed facilitates the assembly of the composite safety assembly 500 itself, and facilitates the assembly of the composite safety assembly 500 within the battery cover plate assembly 400. In addition, the upper surface of the upper conductive sheet 521 is designed to protrude out of the upper surface of the insulating sealing ring 523, and the lower surface of the lower conductive sheet 522 is designed to protrude out of the lower surface of the insulating sealing ring 523, so that the composite safety assembly 500 is conveniently connected in series between the upper surface of the conductive plate 410 and the negative electrode terminal 422.

In one embodiment, as shown in fig. 4 to 7, the memory alloy member 511 is a zigzag folded sheet, and one end of the current limiting element 512 is fixedly and electrically connected to the lower conductive sheet 522, and the other end is fixedly and electrically connected to the memory alloy member 511. As shown in fig. 5 and 7, when the temperature is lower than the first temperature, the memory alloy piece 511 is in a compressed state, a space 600 exists between the other end of the memory alloy piece and the upper conducting piece 521, and the conducting plate 410 and the negative terminal 422 are insulated from each other; when the temperature rises to the first temperature, as shown in fig. 6, the memory alloy member 511 is transformed from the compressed state to the expanded state, and the other end of the memory alloy member 511 is brought into contact with the upper conductive sheet 521 to eliminate the gap 600 and to conduct the negative terminal 422 and the conductive plate 410, so that the battery forms an external short circuit, and the current limiting element 512 connected in series with the memory alloy member 511 serves to limit the short-circuit current. In addition, in other embodiments, one end of the current limiting element 512 may also be fixedly and electrically connected to the upper conductive plate 521, and the other end of the current limiting element may also be fixedly and electrically connected to the memory alloy piece 511, when the memory alloy piece 511 is in the compressed state, a gap 600 may exist between the other end of the memory alloy piece and the lower conductive plate 522, and when the memory alloy piece 511 is in the extended state, the other end of the memory alloy piece may contact the lower conductive plate 522.

In another embodiment, the composite safety assembly 500 is configured as shown in fig. 8, one end of the current limiting element 512 is fixedly connected to the lower conductive plate 522, one end of the memory alloy piece 511 is fixedly connected to the upper conductive plate 521, a gap 600 is formed between the other end of the memory alloy piece and the other end of the current limiting element 512 when the memory alloy piece 511 is in a compressed state, and the other end of the memory alloy piece is in contact with the other end of the current limiting element 512 when the memory alloy piece 511 is in an extended state, so as to eliminate the gap 600 and conduct the negative terminal 422 and the conductive plate 410. It should be noted that, in other embodiments, the positions of the memory alloy element 511 and the current limiting element 512 may also be reversed, and are not described herein again.

In yet another embodiment, the structure of the composite safety device 500 is as shown in fig. 9, the current limiting element 512 includes a first resistive element 513 and a second resistive element 514, the first resistive element 513 is a PTC element or a fixed-value resistive element, and the second resistive element 514 is a PTC element or a fixed-value resistive element; one end of the first resistance member 513 is fixedly and electrically connected with the upper conductive sheet 521; one end of the second resistance member 514 is fixedly and electrically connected with the lower conductive sheet 522, the other end is fixedly and electrically connected with one end of the memory alloy member 511, when the memory alloy member 511 is in a compressed state, a gap 600 is formed between the other end of the memory alloy sheet and the other end of the first resistance member 513, and when the memory alloy member 511 is in an extended state, the other end of the memory alloy sheet is in contact with the other end of the first resistance member 513 to eliminate the gap 600 and conduct the negative terminal 422 and the conductive plate 410. It should be noted that, in other embodiments, the positions of the first resistive element 513 and the second resistive element 514 may also be reversed, and are not described herein again.

In addition, in one embodiment, the structure of the composite safety device 500 is as shown in fig. 10 and 11, the composite safety device 500 may only include the internal element 510, that is, the composite safety device 500 may only include the memory alloy piece 511 and the current limiting element 512 connected in series with each other, one end of the current limiting element 512 is directly and fixedly connected to the conductive plate 410, the other end of the current limiting element 512 is fixedly connected to the memory alloy piece 511, when the memory alloy piece 511 is in a compressed state, the interval 600 exists between the other end of the memory alloy piece and the negative terminal 422, and when the memory alloy piece 511 is in an extended state, the other end of the memory alloy piece 511 contacts the negative terminal 422 to eliminate the interval 600 and to conduct the negative terminal 422 and the conductive plate 410. In addition, the present invention is not limited to the manner of fixing the electrical connection between the two members, and may be applied by means of bonding with a conductive adhesive or by other means such as welding. In addition, when the composite safety assembly 500 includes the external element 520, since the upper conductive plate 521 is already fixedly and electrically connected to the negative terminal 422 and the lower conductive plate 522 is already fixedly and electrically connected to the conductive plate 410, one end of the current limiting element 512 or the memory alloy 511 is fixedly and electrically connected to the upper conductive plate 521, that is, one end of the current limiting element 512 or the memory alloy 511 is indirectly and fixedly and electrically connected to the negative terminal 422, and one end of the current limiting element 512 or the memory alloy 511 is fixedly and electrically connected to the lower conductive plate 522, that is, one end of the current limiting element 512 or the memory alloy 511 is indirectly and fixedly and electrically connected to the conductive plate 410.

In a specific embodiment, the memory alloy piece 511 is at least one or a combination of Au-Cd, Ag-Cd, Cu-Zn-M (M ═ Al, Sn, Si, Ga, Au), In-Ti, Ni-Al, Fe-Pt, Ti-Ni-Pd, Ti-Nb, U-Nb, Fe-Mn-Si; the first temperature is in the range of 40 ℃ to 80 ℃. The memory alloy piece 511 made of different materials has different temperature for state transition, and in a specific application scene, the specific material of the memory alloy piece 511 can be reasonably selected according to the needs. In one embodiment, the memory alloy member 511 has a one-way shape memory effect, and the memory alloy member 511 is manufactured to be in a stretched state in an environment higher than a first temperature and is compressed to be in a compressed state in a environment lower than the first temperature, so that the conductive plate 410 and the negative terminal 422 are insulated from each other by a space 600, as shown in fig. 5 and 7; when the temperature rises to the first temperature, the memory alloy member 511 is restored from the compressed state to the expanded state, so that the space 600 between the negative terminal 422 and the conductive plate 410 is removed and conducted with each other, and the battery forms an external short circuit, as shown in fig. 6.

In another embodiment, the memory alloy 511 has a two-way shape memory effect and is made to compress below a first temperature and to expand above the first temperature. When the temperature is lower than the first temperature, the memory alloy member 511 is in a compressed state, so that the conductive plate 410 and the negative terminal 422 are insulated from each other by a space 600, as shown in fig. 5 and 7. When the temperature rises to the first temperature, the memory alloy member 511 is transformed from the compressed state to the expanded state, so that the space 600 between the negative terminal 422 and the conductive plate 410 is removed and conducted with each other, and the battery forms an external short circuit, as shown in fig. 6. When the temperature is reduced below the first temperature, the memory alloy member 511 is transformed from the expanded state to the compressed state, so that the negative terminal 422 and the conductive plate 410 are restored to a state in which the space 600 exists and are insulated, as shown in fig. 5 and 7.

In one embodiment, the current limiting element 512 in the composite safety assembly 500 is a fixed value resistive element or a PTC element; the resistance range of the constant value resistance element is 1 x 10^-3Ω-1*10³Omega; the PTC element has a resistance suddenly increased at a second temperature to limit short-circuit current, the second temperature is higher than the first temperature, and after the resistance suddenly increased, the resistance of the PTC element is in a range of 1 x 10^-3Ω-1*10³Omega. In a specific embodiment, the second temperature is in the range of 70 ℃ to 150 ℃. In another specific embodiment, the material of the memory alloy piece 511 is Ni — Ti alloy, and the first temperature of the memory alloy piece 511 from the occurrence of the state transition is in a range of 55 ℃ to 75 ℃; the current limiting element 512 is a PTC element and the second temperature at which the PTC element experiences a sudden increase in resistance is in the range of 80 c to 120 c.

In one specific embodiment, the conductive plate 410 is a piece of aluminum foil and the current limiting element 512 in the composite safety assembly 500 is a PTC element. When the charging temperature of the battery is normal, the memory alloy piece 511 is in a compressed state, where the normal charging temperature refers to a normal temperature environment with a temperature less than 40 ℃, and the conductive plate 410 and the negative terminal 422 have a space 600 therebetween and are insulated from each other, that is, the memory alloy piece 511 at normal temperature can prevent the negative terminal 422 from being conducted with the conductive plate 410, thereby preventing the battery from forming an external short circuit. When overcharge occurs, heat is generated inside the battery, and the negative pole 452 generates joule heat itself, when the temperature of the memory alloy 511 in the composite safety assembly 500 reaches a first temperature, for example, 68 ℃, the memory alloy is converted from a compression state to an extension state, and the space 600 between the conductive plate 410 and the negative pole terminal 422 is eliminated, so that the negative pole terminal 422 and the conductive plate 410 are conducted to form an external short circuit, and the internal energy of the battery is released in time; meanwhile, as the short-circuit discharge progresses, the temperature of the negative pole column 452 further rises, and when the temperature of the PTC element in the composite safety assembly 500 reaches a second temperature, for example, 100 ℃, the resistance of the PTC element rapidly increases, so that the short-circuit can be effectively limited, and the thermal runaway of the power battery can be prevented, thereby realizing the overcharge and overheat protection of the lithium ion battery, and improving the safety of the power battery during charging.

In another specific embodiment, the memory alloy 511 has a two-way shape memory effect, when the battery is exposed to a high temperature environment in a standing state, the external environment transfers heat to the composite safety assembly 500 through the negative terminal 422 and the aluminum flake, when the temperature of the memory alloy 511 in the composite safety assembly 500 reaches a first temperature, for example, 68 ℃, the memory alloy is converted from a compression state to an extension state, the space 600 between the conductive plate 410 and the negative terminal 422 is eliminated, the negative terminal 422 and the conductive plate 410 are conducted, an external short circuit is formed, and the internal energy of the battery is released in time; meanwhile, as the short-circuit discharge progresses, the temperature of the negative pole column 452 further rises, and when the temperature of the PTC component in the composite safety assembly 500 reaches its transition temperature, for example, 100 ℃, the resistance of the PTC component increases rapidly, so that the short-circuit can be effectively limited, and the power battery is prevented from thermal runaway, thereby realizing protection of the lithium ion battery from an overheat environment, and improving the safety of the power battery when the power battery is overheated. When the temperature of the external environment is reduced below the first temperature, the memory alloy member 511 in the composite safety device 500 is transformed from the expanded state to the compressed state to restore the state in which the space 600 exists and the conductive plate 410 is insulated between the negative terminal 422 and the conductive plate 410, as shown in fig. 5 and 7, thereby enabling the battery to be restored to the normal state.

In a further specific embodiment, the current limiting element 512 of the composite safety device 500 is a constant resistance element, when the battery temperature is normal, the memory alloy 511 of the composite safety device 500 is in a compressed state, and the conductive plate 410 and the negative terminal 422 are isolated from each other by a gap 600; when the battery is in an external short circuit, heat generated inside the battery and the temperature of the memory alloy part 511 in the composite safety component 500 under the action of joule heat of the negative pole column 452 per se quickly reach a first temperature, for example, 68 ℃, the memory alloy part 511 is converted from a compression state to an extension state, the interval 600 between the conductive plate 410 and the negative pole terminal 422 is eliminated, the negative pole terminal 422 and the conductive plate 410 are conducted to form an external short circuit, the internal energy of the battery is released in time, the constant value resistance element can effectively limit a short circuit, the thermal runaway of the power battery is prevented, the short circuit of the lithium ion battery is protected from overheating, and the safety of the power battery during charging is improved.

The battery cover plate assembly 400 and the single battery 10 of the present invention have the advantages that the composite safety assembly 500 is connected in series between the negative terminal 422 and the conductive plate 410, and gas generation additives such as lithium carbonate are not added in the battery pole piece, so that the cycle and storage performance of the battery are not affected; in addition, by arranging the current limiting element 512 in the composite safety assembly 500, the short-circuit discharge current can be effectively limited, and the risk that the battery temperature continuously rises to cause the ignition and explosion of the battery core 100 is avoided.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A battery cover plate component is characterized by comprising a conductive plate, a positive terminal, a negative terminal and a composite safety component; the positive terminal can be electrically connected with a positive electrode lug of the battery cell, and the negative terminal can be electrically connected with a negative electrode lug of the battery cell; the positive terminal is electrically connected above the conductive plate, and the composite safety assembly is connected between the upper surface of the conductive plate and the negative terminal in series;

the composite safety assembly comprises a memory alloy piece and a current limiting element, wherein the memory alloy piece and the current limiting element can be mutually connected in series, the memory alloy piece is used for being converted from a compression state to an extension state when the temperature is increased to a first temperature so as to conduct a negative terminal and a conductive plate to enable the battery to form an external short circuit, and the current limiting element is used for limiting short-circuit current;

when the temperature is lower than a first temperature, the memory alloy piece is in a compressed state, and a gap is reserved between the negative terminal and the conductive plate and is insulated; when the memory alloy member is transformed into the expanded state, the gap disappears and the negative terminal is conducted with the conductive plate.

2. The battery cover plate assembly of claim 1, wherein the memory alloy member is at least one or a combination of Au-Cd, Ag-Cd, Cu-Zn-M (M ═ Al, Sn, Si, Ga, Au), In-Ti, Ni-Al, Fe-Pt, Ti-Ni-Pd, Ti-Nb, U-Nb, Fe-Mn-Si; the first temperature is in the range of 40 ℃ to 80 ℃.

3. The battery cover plate assembly of claim 1, wherein the memory alloy member has a two-way shape memory effect, and returns from a stretched state to a compressed state when the temperature is reduced below the first temperature to restore the spaced and insulated state between the negative terminal and the conductive plate.

4. The battery cover plate assembly of claim 1, wherein the current limiting element is a fixed resistance element or a PTC element; the resistance range of the constant value resistance element is 1 x 10^-3Ω-1*10³Omega; the PTC element has a resistance suddenly increased at a second temperature to limit short-circuit current, the second temperature is higher than the first temperature, and after the resistance suddenly increased, the resistance of the PTC element ranges from 1 x 10^-3Ω-1*10³Ω。

5. The battery cover plate assembly of claim 4, wherein the second temperature is in a range of 70 ℃ to 150 ℃.

6. The battery cover plate assembly of claim 1, wherein the composite safety assembly comprises an inner element and an outer element, the inner element comprising the memory alloy member and a current limiting element; the external element comprises an upper conducting strip, a lower conducting strip and an insulating sealing ring, a mounting hole is formed in the insulating sealing ring, and the upper conducting strip is arranged above the mounting hole and is electrically connected with the negative terminal; the lower conducting plate is arranged below the mounting hole and is electrically connected with the conducting plate; the internal element is arranged in the mounting hole, and one end of the internal element is fixedly connected with the upper conducting strip or the lower conducting strip.

7. The battery cover plate assembly of claim 6, wherein a first groove is formed in the upper surface of the insulating seal ring, the first groove is communicated with the mounting hole, the upper conducting plate is embedded in the first groove, and the upper surface of the upper conducting plate protrudes out of the upper surface of the insulating seal ring; the lower surface of the insulating sealing ring is provided with a second groove, the second groove is communicated with the mounting hole, the lower conducting strip is embedded in the second groove, and the lower surface of the lower conducting strip protrudes out of the lower surface of the insulating sealing ring.

8. The battery cover plate assembly of claim 1, further comprising an insulating gasket, a positive post, a negative post, and an insulating sealing plug; the insulating gasket is arranged between the current conducting plate and the negative terminal, a first conducting hole and a second conducting hole which are mutually spaced are formed in the current conducting plate, a third conducting hole and a fourth conducting hole which are mutually spaced are formed in the insulating gasket, the composite safety component is arranged in the fourth conducting hole, and the positive pole is arranged in the first conducting hole in a penetrating mode and used for electrically connecting a positive pole lug and a positive terminal of the battery cell; the positions of the second via hole and the third via hole correspond to each other, and the negative pole column sequentially penetrates through the second via hole and the third via hole and is used for electrically connecting a negative pole lug of the battery cell with a negative pole terminal; the insulating sealing plug is arranged between the hole wall of the current-conducting plate and the positive pole column and the negative pole column in a sealing mode.

9. The battery cover plate assembly of any one of claims 1-8, wherein the memory alloy member is in the form of a Z-folded sheet; and the number of the first and second electrodes,

one end of the current limiting element is fixedly and electrically connected with one of the conductive plate and the negative terminal, the other end of the current limiting element is fixedly and electrically connected with the memory alloy piece, when the memory alloy piece is in a compressed state, a gap is formed between the other end of the memory alloy piece and the other one of the conductive plate and the negative terminal, and when the memory alloy piece is in an extended state, the other end of the memory alloy piece is in contact with the other one of the conductive plate and the negative terminal so as to eliminate the gap and conduct the negative terminal and the conductive plate;

or one end of the current-limiting element is fixedly and electrically connected with one of the conductive plate and the negative terminal, one end of the memory alloy piece is fixedly and electrically connected with the other one of the conductive plate and the negative terminal, when the memory alloy piece is in a compressed state, a gap is formed between the other end of the memory alloy piece and the other end of the current-limiting element, and when the memory alloy piece is in an extended state, the other end of the memory alloy piece is in contact with the other end of the current-limiting element so as to eliminate the gap and conduct the negative terminal and the conductive plate;

or, the current limiting element comprises a first resistance element and a second resistance element, the first resistance element is a PTC element or a constant value resistance element, the second resistance element is a PTC element or a constant value resistance element, the PTC element is used for increasing resistance suddenly at a second temperature so as to limit short-circuit current, and the second temperature is higher than the first temperature; one end of the first resistance piece is fixedly and electrically connected with one of the conductive plate and the negative terminal, and the other end of the first resistance piece is fixedly and electrically connected with one end of the memory alloy piece; one end of the second resistance piece is fixedly and electrically connected with the other one of the conductive plate and the negative terminal, when the memory alloy piece is in a compressed state, a gap is formed between the other end of the memory alloy piece and the other end of the second resistance piece, and when the memory alloy piece is in an extended state, the other end of the memory alloy piece is in contact with the other end of the second resistance piece, so that the gap is eliminated, and the negative terminal is conducted with the conductive plate.

10. A single battery, comprising a battery core, an insulating film, a shell and the battery cover assembly of any one of claims 1 to 9, wherein the battery core is provided with a positive electrode tab and a negative electrode tab, the positive electrode tab is used for being electrically connected with the positive electrode terminal, and the negative electrode tab is used for being electrically connected with the negative electrode terminal; the insulation film is coated outside the battery core, the battery core and the insulation film are arranged in the shell, an opening is formed in the upper portion of the shell, and the battery cover plate assembly is covered on the opening of the shell.