Insulating member, tab assembly, battery cell, battery, and electric device

Abstract

The present application discloses an insulating member, a tab assembly, a battery cell, a battery, and an electric device. The insulating member is configured to be connected to a tab, and comprises a first base layer, a first packaging layer, and a second packaging layer, wherein the first base layer is located between the first packaging layer and the second packaging layer, and the melting point A of the first base layer satisfies A≥185°C. When the temperature rises significantly, the insulating member is melted, and thus the tab comes into contact with a metal layer of an electrode assembly or a battery cell casing, resulting in a short circuit. The first base layer having a relatively high melting point is provided, thereby reducing the risk of a short circuit caused by the melting of the first base layer.

Description

Insulation parts, tab components, battery cells, batteries and electrical equipment Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an insulating member, a tab assembly, a battery cell, a battery, and an electrical device. Background Art

[0002] With the continuous updating and development of lithium-ion battery technology, the application fields of lithium-ion batteries are also expanding. The resulting battery cell safety issues are receiving more and more public attention. Lithium-ion battery safety accidents characterized by battery thermal runaway caused by external short circuits occur frequently, which brings certain resistance to the development of lithium-ion batteries. How to solve the battery cell safety issue is a difficult problem that the current lithium-ion battery industry cannot avoid. Summary of the Invention

[0003] In view of this, it is necessary to provide an insulating part, a tab assembly, a battery cell, a battery and an electrical device to reduce the risk of short circuit.

[0004] An embodiment of the present application provides an insulating member configured to connect a tab, comprising a first base layer, a first encapsulation layer, and a second encapsulation layer. The first base layer is positioned between the first and second encapsulation layers, and the melting point A of the first base layer satisfies A ≥ 185°C. When the temperature rises significantly, the insulating member melts, causing the tab to contact the metal layer of the electrode assembly or the battery cell casing, resulting in a short circuit. By providing a first base layer with a higher melting point, the risk of a short circuit caused by melting of the first base layer is reduced.

[0005] In one or more of the above optional embodiments, the melting point of the first substrate layer is higher than that of the first encapsulation layer. When the temperature inside the battery cell rises, the first encapsulation layer may melt first and form a pressure relief channel, which is beneficial for pressure relief. The melting point of the first substrate layer is higher than that of the second encapsulation layer. When the temperature inside the battery cell rises, the second encapsulation layer may melt first and form a pressure relief channel, which is beneficial for pressure relief and reduces the risk of fire.

[0006] In one or more of the above optional embodiments, the thickness of the first base layer is 6% to 10% of the thickness of the insulating member, which is beneficial to reducing the appearance of pores and channels in the battery cell housing and the risk of leakage and short circuit. If the thickness of the first base layer is too thick, pores and channels may easily appear in the packaging triangle area of ​​the sealing portion (the edge area of ​​the insulating member). If the thickness of the first base layer is too thin, it may easily melt, resulting in exposure of the tab and further short circuit.

[0007] In one or more of the above optional embodiments, 220°C ≤ A ≤ 400°C is further beneficial to reducing the risk of short circuit caused by contact between the tab and the metal layer of the battery cell shell, and causing thermal runaway.

[0008] In one or more of the above optional embodiments, 300°C ≤ A ≤ 500°C can further help reduce the risk of short circuit caused by contact between the tab and the metal layer of the battery cell shell, and triggering thermal runaway.

[0009] In one or more of the above optional embodiments, the melting point B of the first packaging layer satisfies 115°C≤B≤145°C, which is beneficial for depressurizing the interior of the battery cell shell, improving safety, and reducing the occurrence of premature failure of the battery cell, which is beneficial for increasing the service life of the battery cell.

[0010] In one or more of the above optional embodiments, the melting point C of the second packaging layer satisfies 115°C≤C≤145°C, which is beneficial to relieving pressure inside the battery cell shell, improving safety, and reducing the occurrence of premature failure of the battery cell, which is beneficial to increasing the service life of the battery cell.

[0011] In one or more of the above optional embodiments, the thickness of the first packaging layer is 30% to 44% of the thickness of the insulating member, which is beneficial to improving the connection strength between the first packaging layer and the adhesive layer, facilitating pressure relief and reducing occupied space.

[0012] In one or more optional embodiments above, the thickness of the second packaging layer is 30% to 44% of the thickness of the insulating member, which is beneficial to improving the connection strength between the second packaging layer and the tab, facilitating pressure relief and reducing occupied space.

[0013] In one or more optional embodiments above, the insulating member includes two connecting layers, the first encapsulation layer is connected to the first base layer through one of the connecting layers, and the second encapsulation layer is connected to the first base layer through the other connecting layer.

[0014] In one or more of the above optional embodiments, the thickness of the connection layer is 3% to 8% of the thickness of the insulating member, which can improve the connection strength between the first base layer and the first packaging layer and reduce the occupied space.

[0015] In one or more optional embodiments above, the difference between the melting point of the first substrate layer and the melting point of the first encapsulation layer is greater than 62° C., and / or the difference between the melting point of the first substrate layer and the melting point of the second encapsulation layer is greater than 62° C., reducing the risk of short circuit.

[0016] In one or more optional embodiments above, the difference between the melting point of the first substrate layer and the melting point of the first encapsulation layer is greater than 147°C, and\or the difference between the melting point of the first substrate layer and the melting point of the second encapsulation layer is greater than 147°C, further reducing the risk of short circuit.

[0017] In one or more optional embodiments above, the difference between the melting point of the first substrate layer and the melting point of the first encapsulation layer is greater than 227°C, and\or the difference between the melting point of the first substrate layer and the melting point of the second encapsulation layer is greater than 227°C, further reducing the short circuit risk.

[0018] In one or more optional embodiments above, when the temperature is greater than 180°C, the softening melting range of the first substrate layer is 200°C-500°C.

[0019] In one or more of the above optional embodiments, the melting range of the insulating member is 200°C-500°C.

[0020] In one or more of the above optional embodiments, the melting point D of the connecting layer is 100°C≤D≤180°C.

[0021] In one or more optional embodiments above, the connecting layer comprises one or more of hot melt adhesive, aminosilane adhesive, polyurethane adhesive, epoxy resin, and acrylic adhesive.

[0022] In one or more optional embodiments above, the connecting layer comprises a first type of glue and a second type of glue, the first type of glue comprises one or more of silica gel, a thickener, and a phenolic resin, and the second type of glue comprises one or more of a silane coupling agent, a curing agent, and an amino resin.

[0023] In one or more optional embodiments above, the first substrate layer comprises one or more of polyimide, polyamideimide, polyethyleneimine, polyethylene naphthalate, polyethylene terephthalate, and modified polypropylene.

[0024] An embodiment of the present application provides a tab assembly, comprising a tab and two insulating members according to any one of the above embodiments. The tab is disposed between the two insulating members along the thickness direction of the tab.

[0025] In one or more optional embodiments above, the tab assembly is immersed in dimethyl carbonate for 24 hours, and the peel strength between the tab and the insulating member is 0.2-2.0 N / mm.

[0026] An embodiment of the present application provides a battery cell including a battery cell shell, an electrode assembly, and a tab assembly. The tab assembly includes a tab and two insulating parts. The battery cell shell includes a main body and a sealing part. The electrode assembly is arranged in the main body. The tab is connected to the electrode assembly and extends from the sealing part. Along the thickness direction of the tab, the tab is arranged between the two insulating parts. Each insulating part includes a first base layer, a first packaging layer and a second packaging layer. Along the thickness direction of the tab, the first base layer is located between the first packaging layer and the second packaging layer. The first packaging layer is connected to the sealing part, and the second packaging layer is connected to the tab. When the temperature is greater than 180°C, the melting point A of the first base layer satisfies A≥185°C. When the temperature rise is large, the insulating part is melted, and the tab contacts the metal layer of the electrode assembly or the battery cell shell, resulting in a short circuit. The present application reduces the risk of a short circuit caused by the melting of the first base layer by providing a first base layer with a higher melting point.

[0027] In one or more of the above optional embodiments, the sealing portion includes two adhesive layers along the thickness direction of the battery cell housing. Along the thickness direction of the battery cell housing, the sealing portion includes a first region that does not overlap with the insulating member, and the two adhesive layers located in the first region are bonded together. Twice the thickness of the first base layer is less than the sum of the thicknesses of the two adhesive layers, or the sum of the thicknesses of the first base layers on both sides of the tab is less than the sum of the thicknesses of the two adhesive layers. This reduces the formation of pores and channels in the battery cell housing, thereby reducing the risk of leakage and short circuits.

[0028] In one or more of the above optional embodiments, the sum of the thickness of the insulating member and the thickness of the adhesive layer is less than the sum of the thicknesses of the two adhesive layers, further reducing the occurrence of pore channels in the battery cell shell and reducing the risk of leakage and short circuit.

[0029] In one or more optional embodiments above, along the thickness direction of the battery cell shell, the sealing portion includes a second region that overlaps with the insulating member and does not overlap with the tab, the second region is adjacent to the first region, and along the thickness direction of the tab, the difference between the thickness of the first region and the thickness of the second region is less than 50 μm.

[0030] In one or more of the above optional embodiments, the tab includes a first section, a second section, and a third section. At least a portion of the first section is connected to the electrode assembly. The second section is bent and connected to the first section, and the second section accounts for 5%-70% of the thickness of the battery cell. The third section is bent and connected to the second section, and a portion of the third section extends beyond the sealing portion.

[0031] An embodiment of the present application provides a battery, comprising the battery cell in any one of the above embodiments.

[0032] An embodiment of the present application provides an electrical device, comprising the battery in any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic structural diagram of a battery cell in some embodiments.

[0034] FIG2 shows an exploded schematic diagram of a battery cell in some embodiments.

[0035] FIG3 shows a schematic cross-sectional view of a battery cell in some embodiments.

[0036] FIG4 is a schematic cross-sectional view of a battery cell casing in some embodiments.

[0037] FIG5 is a schematic structural diagram of a tab, a first insulating member, and a second insulating member in some embodiments.

[0038] FIG6 shows a schematic structural diagram of batteries and electrical devices in other embodiments.

[0039] Description of the main component symbols: Battery cell 100 First region 101 Second region 102 Battery cell housing 10 Adhesive layer 10a Metal layer 10b Outer layer 10c Main body 11 First housing 111 First recess 111a Second housing 112 Second recess 112a First extended edge 113 Second extended edge 114 Sealing portion 12 First sealing portion 12a Second sealing portion 12b Electrode assembly 20 First pole piece 21 Second pole piece 22 Separator 23 Tab 30 First segment 31 Second segment32 Third section 33 First protective layer 100a Insulation member 40 First base layer 41 First packaging layer 42 Second packaging layer 43 Connecting layer 44 Tab assembly 120 Battery 200 Electrical device 300

[0040] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0041] The following detailed description is illustrative and non-limiting. It is intended to provide a basic understanding of the present application and is not intended to identify the key or decisive elements of the present application or to limit the scope of protection. As long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any manner.

[0042] When a component is referred to as being “disposed on” another component, it can be directly disposed on the other component or there may be a component intervening therebetween. When a component is referred to as being “connected to” another component, it can be directly connected to the other component or there may be a component intervening therebetween.

[0043] Unless otherwise defined, the term "plurality" herein, when used to describe the number of components, specifically means that the components are two or more.

[0044] An embodiment of the present application provides a battery cell including a battery cell shell, an electrode assembly, and a tab assembly. The battery cell shell includes a main body and a sealing portion. The electrode assembly is arranged in the main body. The tab assembly includes a tab and two insulating parts. The tab is connected to the electrode assembly and extends from the sealing portion. Along the thickness direction of the tab, the tab is arranged between the two insulating parts. Each insulating part includes a first base layer, a first packaging layer and a second packaging layer. Along the thickness direction of the tab, the first base layer is located between the first packaging layer and the second packaging layer. The first packaging layer is connected to the sealing portion, and the second packaging layer is connected to the tab. When the temperature is greater than 180°C, the melting point A of the first base layer satisfies A≥185°C. When the temperature rise is large, the insulating part is melted, causing the tab to contact the metal layer of the electrode assembly or the battery cell shell, resulting in a short circuit. The present application reduces the risk of a short circuit caused by the melting of the first base layer by providing a first base layer with a higher melting point.

[0045] The following will describe some embodiments of the present application in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0046] Referring to Figures 1 to 5 , one embodiment of the present application provides a battery cell 100 comprising a battery cell housing 10, an electrode assembly 20, and a tab assembly 120. The tab assembly 120 comprises a tab 30 and two insulating members 40. The electrode assembly 20 is disposed within the battery cell housing 10. The tab 30 is connected to the electrode assembly 20 and extends from the battery cell housing 10. Along the thickness direction of the tab 30, the tab 30 is disposed between the two insulating members 40.

[0047] In some embodiments, the battery cell shell 10 may be a packaging bag encapsulated by a packaging film (such as an aluminum-plastic film), that is, the battery cell 100 is a soft-pack battery cell.

[0048] In some embodiments, the cell casing 10 includes a stacked adhesive layer 10a, a metal layer 10b, and an outer layer 10c. The metal layer 10b is disposed between the adhesive layer 10a and the outer layer 10c, and the outer layer 10c is located at the outermost layer of the cell casing 10. The outer layer 10c can be a nylon layer or a composite layer of polyester resin (PET) and nylon, and provides protection against pollution, corrosion, and damage from external forces. The metal layer 10b can include one of aluminum and steel, and provides waterproofing, a barrier function, and helps shape the cell casing 10. The adhesive layer 10a is a heat-sealing layer and can include a polymer, including one of polypropylene and polyethylene. The adhesive layer 10a is used to seal the cell casing 10 by hot pressing and to separate the metal layer 10b from the electrode assembly 20, thereby reducing the risk of electrolyte leakage from the cell casing 10 and corrosion of the metal layer 10b.

[0049] In some embodiments, the cell housing 10 includes a main body 11 and a sealing portion 12 , wherein the main body 11 is connected to the sealing portion 12 . The electrode assembly 20 is disposed on the main body 11 , and the tab 30 extends from the sealing portion 12 out of the cell housing 10 .

[0050] In some embodiments, the main body 11 includes a first shell 111 and a second shell 112. The first shell 111 is provided with a first recess 111a, and the second shell 112 is provided with a second recess 112a. The first shell 111 is connected to the second shell 112 to form a storage space. Part of the electrode assembly 20 is provided in the first recess 111a, and part is provided in the second recess 112a. The circumferential side of the first shell 111 extends outward to form a first extended edge 113, and the circumferential side of the second shell 112 extends outward to form a second extended edge 114. After the first shell 111 is connected to the second shell 112, the first extended edge 113 and the second extended edge 114 overlap and are sealed and connected to form a sealing portion 12.

[0051] In some embodiments, the first shell 111 and the second shell 112 may be an integral structure or a separate structure.

[0052] In some embodiments, the sealing portion 12 includes a first sealing portion 12 a , and the tab 30 extends out of the cell casing 10 from the first sealing portion 12 a .

[0053] In some embodiments, the sealing portion 12 includes a second sealing portion 12b connected to the first sealing portion 12a.

[0054] In some embodiments, the electrode assembly 20 includes a first electrode piece 21, a second electrode piece 22, and a separator 23, wherein the separator 23 is disposed between the first electrode piece 21 and the second electrode piece 22. The separator 23 is used to prevent the first electrode piece 21 and the second electrode piece 22 from directly contacting each other, thereby reducing the risk of a short circuit between the first electrode piece 21 and the second electrode piece 22.

[0055] In some embodiments, the electrode assembly 20 is a wound structure, that is, the first electrode piece 21, the separator 23, and the second electrode piece 22 are stacked in sequence and then wound to form the electrode assembly 20. In other embodiments, the electrode assembly 20 can also be a laminated structure, that is, the first electrode piece 21, the separator 23, and the second electrode piece 22 are stacked in sequence to form an electrode assembly unit, and multiple electrode assembly units are stacked to form the electrode assembly 20. In some embodiments, the first electrode piece 21 is a negative electrode piece or a positive electrode piece, and the second electrode piece 22 is a electrode piece with opposite polarity to the first electrode piece 21. This application is described as an example of the first electrode piece 21 being a positive electrode piece and the second electrode piece 22 being a negative electrode piece.

[0056] In some embodiments, the tab 30 includes a first section 31, a second section 32, and a third section 33. At least a portion of the first section 31 is connected to the first pole piece 21 or the second pole piece 22. The second section 32 is bent and connected to the first section 31. The third section 33 is bent and connected to the second section 32, and a portion of the third section 33 extends out of the sealing portion 12. A portion of the third section 33 extends out of the insulating member 40 for connection to other components for energy transmission.

[0057] In some embodiments, the first section 31 is welded to the first pole piece 21 or the second pole piece 22. Welding methods include laser welding, ultrasonic welding, and the like.

[0058] In some embodiments, along the thickness direction of the battery cell 100, the length of the second segment 32 is 5%-70% of the thickness of the battery cell 100, which helps to reduce the head space of the battery cell 100 occupied by the tab 30. Optionally, the length of the second segment 32 is any one of 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, and 70% of the thickness of the battery cell 100.

[0059] In some embodiments, the battery cell 100 includes a first protective layer 100 a , which covers the overlapping portion of the first section 31 and the first electrode 21 , thereby reducing the risk of burrs piercing the isolation membrane 23 and causing a short circuit between the first electrode 21 and the second electrode 22 .

[0060] In some embodiments, the battery cell 100 includes at least three tabs 30. When there are three tabs 30, the polarity of two of the tabs 30 is opposite to the polarity of the other tab 30. When there are four tabs 30, the polarity of three of the tabs 30 is opposite to the polarity of the other tab 30, or the polarity of two of the tabs 30 is opposite to the polarity of the other two tabs 30. When there are three tabs, at least one tab 30 needs to be bent before extending out of the battery cell casing 10.

[0061] Please refer to Figures 3, 4 and 5. In some embodiments, each insulating member 40 includes a first base layer 41, a first packaging layer 42 and a second packaging layer 43. Along the thickness direction of the tab 30, the first base layer 41 is located between the first packaging layer 42 and the second packaging layer 43. The first packaging layer 42 is connected to the sealing portion 12, and the second packaging layer 43 is connected to the tab 30. When the temperature is greater than 180°C, the melting point A of the first base layer 41 satisfies A≥185°C.

[0062] In some embodiments, the tab assembly 120 is immersed in DMC (dimethyl carbonate) for 24 hours, and the peel strength between the tab 30 and the insulating member 40 is 0.2-2.0 N / mm. Within this range, the leakage of the battery cell can be effectively reduced.

[0063] In some embodiments, the test method is as follows:

[0064] The insulating member 40 and the tab 30 were completely immersed in the E173 electrolyte, baked at 85°C for 1D / 3D / 7D / 14D, and then removed from the furnace. After standing at room temperature for 30 minutes, the electrolyte was discarded, and the samples were soaked in anhydrous ethanol for 10 minutes and then dried.

[0065] The insulation 40 and tab 30 were manually peeled apart perpendicular to the tab direction, and the peel strength between the insulation 40 and tab 30 was tested using a high-speed rail tensile tester (test speed: 175 mm / min). After peeling, the insulation 40 did not change color or fall off, and the tab 30 was not corroded.

[0066] In some embodiments, the melting range of the insulating member 40 is between 200°C and 500°C.

[0067] After the tab 30 is bent, the second section 32 is close to the electrode assembly 20. When the temperature rises significantly, the insulating member 40 is melted, causing the tab 30 to contact the electrode assembly 20 or the metal layer 10b of the battery cell shell 10, resulting in a short circuit. In this application, a first base layer 41 with a higher melting point is provided to reduce the risk of a short circuit caused by the melting of the first base layer 41.

[0068] In some embodiments, 220°C ≤ A ≤ 400°C, which is further beneficial to reducing the risk of short circuit caused by contact between the tab 30 and the electrode assembly 20 or the tab 30 and the metal layer 10b, and causing thermal runaway.

[0069] Optionally, the melting point A of the first substrate layer 41 can be any one of 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, and 400℃.

[0070] In some embodiments, 300° C. ≤ A ≤ 500° C. can further help reduce the risk of short circuit caused by contact between the tab 30 and the electrode assembly 20 or between the tab 30 and the metal layer 10 b and inducing thermal runaway.

[0071] Optionally, the melting point A of the first substrate layer 41 can be any one of 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, and 500℃.

[0072] In some embodiments, the melting range of the first base layer 41 is 200° C.-500° C.

[0073] In some embodiments, the material of the first substrate layer 41 includes one or more of polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), or polyamideimide (PAI).

[0074] In some embodiments, the melting point of the material of the first base layer 41 can be adjusted by the following methods:

[0075] Changing molecular weight: Increasing molecular weight can increase the melting point because longer molecular chains increase the interaction between molecules.

[0076] Modifying the molecular structure: Introducing cross-linking or branching structures can increase the melting point. The molecular structure can be adjusted by changing the reaction conditions or using different modification methods.

[0077] Adding fillers or additives: Adding appropriate fillers or additives to polymer materials can change their physical properties, including melting point.

[0078] In some embodiments, the first encapsulation layer 42 is connected to the adhesive layer 10 a . Optionally, the first encapsulation layer 42 is adhesively connected to the adhesive layer 10 a by heat pressing.

[0079] In some embodiments, the melting point of the first packaging layer 42 is lower than that of the first base layer 41 . When the internal temperature of the battery cell 100 rises, the first packaging layer 42 may melt first and form a pressure relief channel, which is conducive to pressure relief and reduces the risk of fire.

[0080] In some embodiments, the melting point B of the first packaging layer 42 satisfies 115°C≤B≤145°C. When the temperature of the melting point B is relatively low (lower than 115°C), the battery cell 100 may fail prematurely, thereby reducing the service life of the battery cell 100. When the temperature of the melting point B is relatively high (higher than 145°C), the pressure relief may not be timely, which is detrimental to the safety of the battery cell 100. By limiting 115°C≤B≤145°C, it is further beneficial to relieve the pressure inside the battery cell shell 10, improve safety, and reduce the occurrence of premature failure of the battery cell 100, which is beneficial to improving the service life of the battery cell 100.

[0081] Optionally, the melting point B of the first encapsulation layer 42 can be any one of 115°C, 116°C, 117°C, 118°C, 119°C, 120°C, 121°C, 122°C, 123°C, 124°C, 125°C, 126°C, 127°C, 128°C, 129°C, 130°C, 131°C, 132°C, 133°C, 134°C, 135°C, 136°C, 137°C, 138°C, 139°C, 140°C, 141°C, 142°C, 143°C, 144°C, and 145°C.

[0082] In some embodiments, satisfying 115°C≤B≤135°C can further facilitate pressure relief.

[0083] In some embodiments, the material of the first encapsulation layer 42 includes polypropylene.

[0084] In some embodiments, the second packaging layer 43 is connected to the tab 30. Optionally, the second packaging layer 43 is bonded to the tab 30 by heat pressing.

[0085] In some embodiments, the melting point of the second packaging layer 43 is lower than that of the first base layer 41 . When the internal temperature of the battery cell 100 increases, the second packaging layer 43 may melt first and form a pressure relief channel, which is beneficial for pressure relief.

[0086] In some embodiments, the melting point C of the second packaging layer 43 satisfies 115℃≤C≤145℃. When the temperature of the melting point C is relatively low (lower than 115℃), the battery cell 100 may fail prematurely, thereby reducing the service life of the battery cell 100. When the temperature of the melting point B is relatively high (higher than 145℃), the pressure relief may not be timely, which is detrimental to the safety of the battery cell 100. By limiting 115℃≤C≤145℃, it is further beneficial to relieve the pressure inside the battery cell shell 10, improve safety, and reduce the occurrence of premature failure of the battery cell 100, which is beneficial to improving the service life of the battery cell 100.

[0087] Optionally, the melting point C of the second encapsulation layer 43 can be any one of 115°C, 116°C, 117°C, 118°C, 119°C, 120°C, 121°C, 122°C, 123°C, 124°C, 125°C, 126°C, 127°C, 128°C, 129°C, 130°C, 131°C, 132°C, 133°C, 134°C, 135°C, 136°C, 137°C, 138°C, 139°C, 140°C, 141°C, 142°C, 143°C, 144°C, and 145°C.

[0088] In some embodiments, satisfying 115°C≤C≤135°C can further facilitate pressure relief.

[0089] In some embodiments, the material of the second encapsulation layer 43 includes polypropylene.

[0090] In some embodiments, the insulating member 40 includes two connecting layers 44 , the first encapsulation layer 42 is connected to the first base layer 41 through one of the connecting layers 44 , and the second encapsulation layer 43 is connected to the first base layer 41 through the other connecting layer 44 .

[0091] Since the first base layer 41 and the first encapsulation layer 42 are made of different materials and have different melting points, and the first base layer 41 and the second encapsulation layer 43 are made of different materials and have different melting points, they cannot be compounded through a high-temperature casting process. The connecting layer 44 facilitates the bonding of the first base layer 41 and the first encapsulation layer 42, as well as the bonding of the first base layer 41 and the second encapsulation layer 43.

[0092] In some embodiments, the material of the connecting layer 44 includes one or more of hot melt adhesive, aminosilane adhesive, polyurethane adhesive, epoxy resin, and acrylic adhesive.

[0093] In some embodiments, the material of the connecting layer 44 includes a first type of glue and a second type of glue, the first type of glue contains one or more of silica gel, thickener, and phenolic resin, and the second type of glue contains one or more of silane coupling agent, curing agent, and amino resin.

[0094] In some embodiments, the melting point D of the connection layer 44 is 100° C. ≤ D ≤ 180° C.

[0095] Optionally, the melting point D of the connecting layer 44 can be any one of 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, and 180°C.

[0096] In some embodiments, when testing the melting point of the first base layer 41, it is necessary to separate the first base layer 41. Partial connecting layers 44 are bonded to both sides of the separated first base layer 41. The melting point of the first base layer 41 is recorded after the temperature is greater than 180°C, thereby reducing the interference of the connecting layer 44 on the testing of the melting point of the first base layer 41.

[0097] In some embodiments, after the first shell 111 and the second shell 112 are connected, the sealing portion 12 includes two adhesive layers 10a along the thickness of the cell shell 10. Along the thickness of the cell shell 10, the sealing portion 12 includes a first region 101 that does not overlap with the insulating member 40. The two adhesive layers 10a in the first region 101 are bonded together. Twice the thickness of the first base layer 41 is less than the sum of the thicknesses of the two adhesive layers 10a after hot pressing, or the sum of the thicknesses of the first base layer 41 on both sides of the tab 30 is less than the sum of the thicknesses of the two adhesive layers 10a. Because the first base layer 41 has a high melting point and cannot melt during the packaging process, an excessively thick first base layer 41 that does not melt after packaging can easily create porous channels, leading to leakage and allowing external moisture to easily enter the cell shell 10, potentially causing a short circuit. By ensuring that half the thickness of the first base layer 41 is less than the sum of the thicknesses of the two adhesive layers 10a after hot pressing, the formation of porous channels in the cell shell 10 is reduced, reducing the risk of leakage and short circuits.

[0098] In some embodiments, the sum of the thickness of the insulating member 40 and the thickness of the adhesive layer 10 a is less than the sum of the thicknesses of the two adhesive layers 10 a , further reducing the occurrence of pore channels in the battery cell housing 10 and lowering the risk of leakage and short circuit.

[0099] In some embodiments, along the thickness direction of the cell casing 10, the sealing portion 12 includes a second region 102 that overlaps with the insulating member 40 and does not overlap with the tab 30. The second region 102 is adjacent to the first region 101. Along the thickness direction of the tab 30, the difference between the thickness of the first region 101 and the thickness of the second region 102 is D, with 60 μm ≤ D ≤ 100 μm. This further reduces the formation of porous channels in the cell casing 10 and reduces the risk of leakage and short circuits. In some embodiments, the thickness of the first base layer 41 is 6% to 10% of the thickness of the insulating member 40. If the thickness of the first base layer 41 is too small (less than 6%), the tab 30 is easily exposed. If the thickness of the first base layer 41 is too large (greater than 10%), leakage and short circuits are likely to occur. By limiting the thickness of the first base layer 41 to 6% to 10% of the thickness of the insulating member 40, the formation of porous channels in the cell casing 10 is reduced, thereby reducing the risk of leakage and short circuits.

[0100] Optionally, the thickness of the first base layer 41 may be any one of 6%, 7%, 8%, 9%, and 10% of the thickness of the insulating member 40 .

[0101] In some embodiments, the thickness d1 of the first base layer 41 is 5 μm≤h1≤8 μm. Alternatively, d1 can be any one of 5 μm, 6 μm, 7 μm, and 8 μm.

[0102] In some embodiments, the thickness of the first encapsulation layer 42 is 30% to 44% of the thickness of the insulating member 40. If the thickness of the first encapsulation layer 42 is too small (less than 30%), the connection strength between the first encapsulation layer 42 and the adhesive layer 10a will be affected, and the pressure relief channel formed by the melting of the first encapsulation layer 42 will be reduced, which is not conducive to pressure relief. If the thickness of the first encapsulation layer 42 is too large (greater than 44%), the occupied space will be increased, affecting the head space of the battery cell 100. By limiting the thickness of the first encapsulation layer 42 to 30% to 44% of the thickness of the insulating member 40, it is beneficial to improve the connection strength between the first encapsulation layer 42 and the adhesive layer 10a, which is beneficial to pressure relief and reduces the occupied space.

[0103] Optionally, the thickness of the first encapsulation layer 42 is any one of 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, and 44% of the thickness of the insulating member 40.

[0104] In some embodiments, the thickness d2 of the first encapsulation layer 42 is 25 μm ≤ d2 ≤ 44 μm. Alternatively, d2 may be any one of 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, and 44 μm.

[0105] In some embodiments, the thickness of the second packaging layer 43 is 30% to 44% of the thickness of the insulating member 40. If the thickness of the second packaging layer 43 is too small (less than 30%), the connection strength between the second packaging layer 43 and the tab 30 will be affected, and the pressure relief channel formed by the melting of the second packaging layer 43 will be reduced, which is not conducive to pressure relief. If the thickness of the second packaging layer 43 is too large (greater than 44%), the occupied space will be increased, affecting the head space of the battery cell 100. By limiting the thickness of the second packaging layer 43 to 30% to 44% of the thickness of the insulating member 40, it is beneficial to improve the connection strength between the second packaging layer 43 and the tab 30, which is beneficial to pressure relief and reduces the occupied space.

[0106] Optionally, the thickness of the second encapsulation layer 43 is any one of 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, and 44% of the thickness of the insulating member 40.

[0107] In some embodiments, the thickness d3 of the second encapsulation layer 43 is 25 μm ≤ d3 ≤ 44 μm. Alternatively, d3 may be any one of 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, and 44 μm.

[0108] In some embodiments, the thickness of the connection layer 44 is 3% to 8% of the thickness of the insulating member 40 .

[0109] In some embodiments, the thickness h1 of the connection layer 44 is 3μm ≤ h1 ≤ 5μm. When the thickness h1 is less than 3μm, the connection strength between the first base layer 41 and the first encapsulation layer 42 is easily affected, and the process cannot achieve the coating precision of too thin a thickness. When the thickness h1 is greater than 5μm, the space occupied increases, affecting the headroom of the battery cell 100. By limiting the range of 3μm ≤ h1 ≤ 5μm, the connection strength between the first base layer 41 and the first encapsulation layer 42 can be improved, while the space occupied can be reduced.

[0110] Optionally, the thickness h1 may be any one of 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4.0 μm, 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, and 5.0 μm.

[0111] In some embodiments, the difference α between the melting point of the first base layer 41 and the melting point of the first encapsulation layer 42 is greater than 62° C., thereby reducing the risk of short circuit.

[0112] In some embodiments, α is ≥ 147°C, further reducing the risk of short circuit. In some embodiments, α is ≥ 227°C, further reducing the risk of short circuit.

[0113] In some embodiments, the difference β between the melting point of the first base layer 41 and the melting point of the second encapsulation layer 43 is greater than 62° C., thereby reducing the risk of short circuit.

[0114] In some embodiments, β is ≥ 147°C, further reducing the risk of short circuit. In some embodiments, β is ≥ 227°C, further reducing the risk of short circuit.

[0115] When the melting point A of the first base layer 41 is greater than or equal to 185° C., the greater the difference α is, the higher the passing rate of the external short-circuit test of the battery cell is.

[0116] The present application will be further described below through specific examples.

[0117] The external short circuit test and 130℃ hot box test were carried out in groups of 100 battery cells.

[0118] In some embodiments, the external short circuit test method includes: 1. Pre-treatment - 1CAP process 1) Test temperature is 20°C (±5°C); 2) Rest 5min; 3) 0.5C CC to 4.5V, CV to 0.025C 4) Rest 5min;

[0119] Testing process:

[0120] Check the appearance and take photos before and after the test;

[0121] Attach the temperature-sensing wire to the center of the cell surface. Place the sample in a test environment at 55±2°C. After the cell surface temperature reaches the test temperature, let it stand for 40±1 minutes. Use an 80±20mΩ load resistor to short-circuit the positive and negative electrodes of the sample and test until the voltage is lower than 0.1V.

[0122] Measurement frequency: Voltage and internal resistance measurements use 1KHz specifications, and are measured after pre-processing and testing.

[0123] Judgment criteria: The surface temperature of the sample does not exceed 150℃, and it does not catch fire or explode.

[0124] The test ends when one of the following conditions is met:

[0125] 1) Stop when the sample voltage is lower than 0.1V and the surface temperature drops to the test environment temperature ±10℃.

[0126] 2) If the voltage cannot be reduced to 0.1V, the surface temperature is allowed to drop to the test environment temperature.

[0127] In some embodiments, the 130°C hot box test method includes: pre-treatment-1CAP process: 1) test temperature is 20°C (±5°C); 2) rest 5min; 3) 0.5°C CCto4.5V, CV to 0.025°C; 4) rest 5min.

[0128] Testing process:

[0129] Check the appearance and take photos before and after the test;

[0130] Temperature sensing line location;

[0131] Place the sample vertically in the box and heat it to 130±2℃ at a rate of 5±2℃ and maintain for 60 minutes;

[0132] Measurement frequency: Voltage and internal resistance measurements use 1KHz specifications, measured after pre-processing and testing;

[0133] Judgment criteria: no fire, no explosion.

[0134] Table 1

[0135] As can be seen from Table 1, on the basis that the melting point A of the first base layer 41 is greater than or equal to 185°C, the higher the melting point of A, the greater the difference α between the melting point A of the first base layer 41 and the melting point B of the first encapsulation layer 42, and the greater the difference β between the melting point A of the first base layer 41 and the melting point B of the second encapsulation layer 43, which can improve the pass rate of the external short circuit test and reduce the short circuit risk.

[0136] On the basis that the melting point A of the first base layer 41 is greater than or equal to 185°C, the melting point B of the first encapsulation layer 42 is within the range of 115°C≤B≤145°C, and the melting point C of the second encapsulation layer 43 is within the range of 115°C≤C≤145°C, the higher the melting point A of the first base layer 41, the lower the melting point B of the first encapsulation layer 42, and the lower the melting point C of the second encapsulation layer 43, the greater the difference α between the melting point A of the first base layer 41 and the melting point B of the first encapsulation layer 42, and the greater the difference β between the melting point A of the first base layer 41 and the melting point B of the second encapsulation layer 43, the higher the external short circuit test pass rate, reducing the short circuit risk, and the higher the 130°C hot box test pass rate, reducing the fire risk.

[0137] 5 , an embodiment of the present application provides a tab assembly 120 , including a tab 30 and two insulating members 40 in any of the above embodiments. Along the thickness direction of the tab 30 , the tab 30 is disposed between the two insulating members 40 .

[0138] In some embodiments, along the width direction of the tab 30 , the width of the insulating member 40 is greater than the width of the tab 30 . In the second region 102 , the second encapsulation layer 43 of one insulating member 40 is bonded to the second encapsulation layer 43 of another insulating member 40 .

[0139] Please refer to FIG. 6 . The present application further provides a battery 200 using the above-mentioned battery cell 100 . The battery 200 includes at least one battery cell 100 .

[0140] 6 , the present application also provides an electrical device 300 using the battery 200. In one embodiment, the electrical device 300 of the present application may be, but is not limited to, electronic equipment, drones, backup power supplies, electric vehicles, electric motorcycles, electric power-assisted bicycles, power tools, large household batteries, and the like.

[0141] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present application and are not intended to limit the present application. As long as they are within the spirit of the present application, appropriate changes and modifications to the above embodiments fall within the scope disclosed in the present application.

Claims

1. An insulating part configured to connect the tab, characterized in that It includes a first base layer, a first encapsulation layer and a second encapsulation layer. The first base layer is located between the first encapsulation layer and the second encapsulation layer, and the melting point A of the first base layer satisfies A≥185°C.

2. The insulating member according to claim 1, wherein The melting point of the first base layer is higher than that of the first encapsulation layer, and the melting point of the first base layer is higher than that of the second encapsulation layer.

3. The insulating member according to claim 1, characterized in that, The thickness of the first base layer is 6% to 10% of the thickness of the insulating part.

4. The insulating member according to any one of claims 1 to 3, characterized in that, 220℃≤A≤400℃。 5. The insulating member according to any one of claims 1 to 3, characterized in that 300℃≤A≤500℃。 6. The insulating member according to any one of claims 1 to 5, characterized in that, The melting point B of the first encapsulation layer satisfies 115°C≤B≤145°C, and / or the melting point C of the second encapsulation layer satisfies 115°C≤C≤145°C.

7. The insulating member according to any one of claims 1 to 6, characterized in that The difference between the melting point of the first base layer and the melting point of the first encapsulation layer is greater than 62°C, and / or the difference between the melting point of the first base layer and the melting point of the second encapsulation layer is greater than 62°C.

8. The insulating member according to any one of claims 1 to 7, characterized in that, The difference between the melting point of the first base layer and the melting point of the first encapsulation layer is greater than 147°C, and / or the difference between the melting point of the first base layer and the melting point of the second encapsulation layer is greater than 147°C.

9. The insulating member according to any one of claims 1 to 8, characterized in that, The difference between the melting point of the first base layer and the melting point of the first encapsulation layer is greater than 227°C, and / or the difference between the melting point of the first base layer and the melting point of the second encapsulation layer is greater than 227°C.

10. The insulating member according to any one of claims 1 to 9, characterized in that, After the temperature is greater than 180°C, the softening melting range of the first base layer is 200°C - 500°C.

11. The insulating member according to any one of claims 1 to 10, characterized in that, The melting range of the insulating part is 200°C - 500°C.

12. The insulating member according to any one of claims 1 to 11, characterized in that, The thickness of the first encapsulation layer is 30% to 44% of the thickness of the insulating part.

13. The insulating member according to any one of claims 1 to 12, characterized in that, The thickness of the second encapsulation layer is 30% to 44% of the thickness of the insulating part.

14. The insulating member according to any one of claims 1 to 13, characterized in that, The insulating part includes two connecting layers. The first encapsulation layer connects the first base layer through one of the connecting layers, and the second encapsulation layer connects the first base layer through the other connecting layer.

15. The insulating member according to claim 14, wherein, The thickness of the connecting layer is 3% to 8% of the thickness of the insulating part.

16. The insulating member according to claim 14, characterized in that, The melting point D of the connecting layer satisfies 100°C≤D≤180°C.

17. The insulating member according to claim 14, characterized in that, The connecting layer contains one or more of hot melt adhesive, amino silane glue, polyurethane glue, epoxy resin, acrylic glue.

18. The insulating member according to any one of claims 14 to 17, characterized in that, The connecting layer contains a first type of glue and a second type of glue. The first type of glue contains one or more of silica gel, thickening agent, phenolic resin, and the second type of glue contains one or more of silane coupling agent, curing agent, amino resin.

19. The insulating member according to any one of claims 1 to 18, characterized in that, The first base layer contains one or more of polyimide, polyamideimide, polyethyleneimine, polyethylene naphthalate, polyethylene terephthalate, modified polypropylene.

20. An electrode tab assembly, characterized in that, It includes a tab and two insulating parts as described in any one of claims 1 to 19. Along the thickness direction of the tab, the tab is arranged between the two insulating parts.

21. The tab assembly according to claim 20, wherein, The tab assembly is immersed in dimethyl carbonate for 24 hours, and the peel strength between the tab and the insulating part is 0.2N / mm - 2.0N / mm.

22. A battery cell, characterized in that, It includes: a battery cell housing, including a main body part and a sealing part; an electrode assembly, arranged inside the main body part; The tab assembly according to any one of claims 20 to 21, wherein the tab is connected to the electrode assembly and extends out of the sealing portion, and in the thickness direction of the tab, the tab is disposed between the two insulating members; Each of the insulating members includes a first base layer, a first encapsulation layer, and a second encapsulation layer. In the thickness direction of the tab, the first base layer is located between the first encapsulation layer and the second encapsulation layer. The first encapsulation layer is connected to the sealing portion, and the second encapsulation layer is connected to the tab. After the temperature is greater than 180 °C, the first base layer has a melting point A, and A≥185 °C.

23. The battery cell according to claim 22, wherein, In the thickness direction of the battery cell housing, the sealing portion includes two adhesive layers; In the thickness direction of the battery cell housing, the sealing portion includes a first region that does not overlap with the insulating member. The two adhesive layers located in the first region are adhesively connected, and twice the thickness of the first base layer is less than the sum of the thicknesses of the two adhesive layers, or the sum of the first base layers on both sides of the tab is less than the sum of the thicknesses of the two adhesive layers.

24. The battery cell according to claim 23, characterized in that, In the sealing portion, the sum of the thickness of the insulating member and the thickness of the adhesive layer is less than the sum of the thicknesses of the two adhesive layers.

25. The battery cell according to claim 23, characterized in that, In the thickness direction of the battery cell housing, the sealing portion includes a second region that overlaps with the insulating member and does not overlap with the tab. The second region is adjacent to the first region. In the thickness direction of the tab, the difference between the thickness of the first region and the thickness of the second region is D, and 60 μm≤D≤100 μm.

26. The battery cell according to any one of claims 22 to 25, characterized in that The tab includes a first section, a second section, and a third section; At least a part of the first section is connected to the electrode assembly; The second section is bent to connect the first section; the second section accounts for 5%-70% of the thickness of the battery cell; The third section is bent to connect the second section, and a part of the third section extends out of the sealing portion.

27. A battery, characterized in that, A battery cell including the battery cell according to any one of claims 22 to 26.

28. An electrical device, characterized in that, A battery including the battery according to claim 27.

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