Pouch battery and electric device using the same

Abstract

This invention relates to the field of new energy technology and discloses a soft-pack battery and an electrical device. The soft-pack battery includes: a casing, a cell, and electrode sheets. The casing has a through-hole suitable for the electrode sheets to pass through, and the electrode sheets are at least partially disposed within the through-hole. A sealing and insulating member is disposed between the electrode sheets and the casing, and along a first direction, the sealing and insulating member is at least partially located within the through-hole. The electrode sheets have a notch at at least one end in a third direction, and the notch is connected to the casing through the sealing and insulating member. Along a second direction, the maximum size of the notch is A mm, and the thickness of the electrode sheet is B mm, satisfying: 0.069 ≤ A / B ≤ 0.889. The soft-pack battery provided by this invention controls A / B within a reasonable range, which can optimize the interlayer bonding form of the hot-press sealing while ensuring the conductivity of the electrode sheets, thereby improving the sealing reliability.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a soft-pack battery and an electrical device. Background Technology

[0002] Due to its simple assembly process and fewer components, pouch batteries are widely used in the field of new energy batteries. However, as users demand higher and higher battery charging and discharging performance, pouch batteries, due to their thin current output end, have an overcurrent bottleneck, resulting in a lower charging and discharging rate, which makes it difficult to meet the application requirements of high-rate charging and discharging. Summary of the Invention

[0003] In view of this, the present invention provides a pouch battery and an electrical device to solve the problem of low charge and discharge rates of pouch batteries.

[0004] In a first aspect, the present invention provides a pouch cell battery, comprising:

[0005] The housing includes a first housing surface and a second housing surface, and an accommodating space is formed between the first housing surface and the second housing surface.

[0006] The battery cell is housed within the containment space;

[0007] An electrode sheet is electrically connected to the battery cell and is adapted to extend from the housing space to the outside of the housing. The housing has a through portion suitable for the electrode sheet to pass through, and the electrode sheet is at least partially disposed in the through portion.

[0008] The direction in which the electrode sheet is led out is the first direction, the thickness direction of the soft-pack battery is the second direction, and the direction perpendicular to the first and second directions is the third direction.

[0009] A sealing and insulating element is disposed between the electrode sheet and the housing, and along the first direction, the sealing and insulating element is at least partially located within the through portion;

[0010] The electrode sheet has a notch at at least one end in the third direction, and the notch is connected to the housing through a sealing and insulating component; along the second direction, the maximum size of the notch is A mm, and the thickness of the electrode sheet is B mm, satisfying: 0.069≤A / B≤0.889.

[0011] Beneficial effects: When the A / B ratio is too large, the maximum size A of the notch is too large, significantly reducing the effective conductive area of ​​the electrode sheet. Conversely, when the electrode sheet thickness B is too small, current transmission capacity decreases, affecting the battery's fast charging and discharging performance. When the A / B ratio is too small, the maximum size A of the notch is too small, resulting in a steep fit between the first and second shell surfaces during hot pressing, leading to stress concentration between layers and increasing the risk of interlayer peeling of the aluminum-plastic film, reducing sealing reliability, and thus increasing the risk of electrolyte leakage. Simultaneously, while a large electrode sheet thickness B helps improve conductivity, it also exacerbates the tendency for interlayer peeling during hot pressing, increasing the probability of sealing gap formation. Therefore, controlling A / B within a reasonable range can optimize the interlayer bonding morphology of hot pressing while ensuring the electrode sheet's conductivity, thereby improving sealing reliability.

[0012] Secondly, the present invention also provides an electrical device, comprising:

[0013] The main body of the electrical device, and the soft-pack battery as described above that is electrically connected to the main body of the electrical device.

[0014] Since the electrical device includes a pouch battery and has the same effect as a pouch battery, it will not be elaborated further here. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the soft-pack battery of the present invention;

[0017] Figure 2 This is an exploded view of the soft package of the present invention;

[0018] Figure 3 This is a top view of the soft case of the present invention;

[0019] Figure 4 for Figure 3 A schematic diagram of the shell with section AA in the middle;

[0020] Figure 5 for Figure 3 Schematic diagram of section AA;

[0021] Figure 6 This is a partially enlarged view of the soft-pack battery of the present invention after the casing has been removed;

[0022] Figure 7This is a schematic diagram of the electrode sheet of the present invention;

[0023] Figure 8 Schematic diagrams of various deformed structures of the electrode sheet of the present invention;

[0024] Figure 9 for Figure 5 A magnified view of a pouch cell with a cross-section of the middle BB (body-block) section;

[0025] Figure 10 for Figure 3 A schematic diagram of another type of soft-pack battery with a cross-section of AA.

[0026] Figure 11 This is a schematic diagram showing the detailed structure of the housing of the present invention;

[0027] Figure 12 This is a schematic diagram of the current output terminal of a pouch battery wrapped with an aluminum-plastic film in the relevant technology.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Housing; 11. First housing surface; 12. Second housing surface; 13. Through portion; 101. Outer insulating layer; 102. Intermediate metal layer; 103. Inner insulating layer; 141. First sealing edge; 142. Second sealing edge; 143. Third sealing edge;

[0030] 2. Battery cell; 3. Electrode plate; 31. Notch; 32. First electrode terminal; 301. First electrode plate; 302. Second electrode plate;

[0031] 4. Sealing and insulating components; 41. Sealing edge; 42. Sealing chamfer;

[0032] 7. Sealing gap; 8. Aluminum-plastic film; 9. Current output terminal. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] Due to its simple assembly process and fewer components, pouch batteries are widely used in the field of new energy batteries. However, as users demand higher and higher battery charging and discharging performance, pouch batteries, due to their thin current output end, have an overcurrent bottleneck, resulting in a lower charging and discharging rate, which makes it difficult to meet the application requirements of high-rate charging and discharging.

[0038] Soft-pack batteries typically use tabs (TABs) as the current output terminal. These TABs act as terminals, welded to the electrode tabs and extending to the outside of the casing to achieve circuit connection. By increasing the overall thickness of the current output terminal (TAB), the external current-carrying cross-sectional area of ​​the battery can be increased, thereby shortening the overall charge and discharge time of the battery.

[0039] Combination Figure 12 As shown, it is a schematic diagram of the current output terminal of a pouch battery wrapped with an aluminum-plastic film in the related technology.

[0040] However, as the thickness of the current output terminal 9 increases, there is a large sealing gap 7 between the aluminum-plastic film 8 and the current output terminal 9, which leads to a decrease in sealing performance. The inside of the battery is easily connected to the outside, which can easily cause electrolyte leakage or external environmental intrusion, thereby affecting the safety of the battery.

[0041] The study found that, especially when the two ends of the current output terminal 9 are at right angles along the width direction, the sealing gap 7 between the aluminum-plastic film 8 and the current output terminal 9 is more obvious, and micropores or voids are easily formed, which increases the risk of sealing failure.

[0042] It should be noted that, in order to facilitate understanding of the technical solution of this application, several technical terms used in the following embodiments will be explained first.

[0043] A battery cell is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of carrying out electrochemical reactions such as charging and discharging.

[0044] A battery cell is the basic unit in a battery, typically consisting of a positive electrode, a negative electrode, and a separator. Battery cells can be either wound or stacked. The main body of a battery cell includes the positive electrode, the negative electrode, and the separator located between the positive and negative electrodes.

[0045] A separator is placed between the positive and negative electrode plates to separate them and prevent short circuits caused by contact. The separator can be at least one of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride.

[0046] Lithium-ion cells primarily function by the insertion and extraction of lithium ions between the positive and negative electrode plates. In cylindrical cells, a three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0047] The positive electrode is one of the core components in a battery that carries the positive electrode active material. During charging, metal ions (e.g., lithium ions) are released from the positive electrode active material (oxidation reaction), migrate through the electrolyte, and intercalate into the negative electrode. During discharging, metal ions (e.g., lithium ions in a lithium battery) are released from the negative electrode and intercalated into the positive electrode active material (reduction reaction), thus realizing the storage and release of lithium ions.

[0048] A positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive active materials for batteries. These positive active materials can be used alone or in combination. The lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, and their modified compounds.

[0049] The positive electrode current collector includes a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. Composite current collectors can also be used, which may include a polymer base layer and a metal layer. Composite current collectors are formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer substrate (such as polyethylene terephthalate, polyethylene terephthalate, polyethylene, polyethylene, etc.).

[0050] The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene and carbon nanofibers.

[0051] The positive electrode binder includes, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0052] During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through the external circuit to maintain charge balance. During discharge, active ions (such as Li) previously embedded in the negative electrode can be released, while electrons from the negative electrode are transferred to the negative electrode through the external circuit to maintain charge balance, thus achieving energy storage and release.

[0053] The negative electrode sheet includes a negative current collector and a negative active layer disposed on at least one surface of the negative current collector. The negative current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. The negative current collector can also be a composite current collector, which may include a polymer base material and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer base material (such as a base material of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.). The negative active layer includes a negative active material, conductive components, and adhesives.

[0054] The negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, and mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-ammonia composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0055] The battery cell also includes tabs, which are located on one side of the positive / negative current collector battery cell and are separately or integrally formed with the current collector. They are electrically connected to the current collector to conduct the current on the corresponding current collector. When the tabs and the current collector are separately set, the tabs and the current collector can be connected by welding.

[0056] The tabs are made of a metal material with good electrical conductivity (such as copper, aluminum, copper or nickel).

[0057] The following is combined Figures 1 to 11 The following describes embodiments of the present invention.

[0058] According to an embodiment of the present invention, in one aspect, a pouch battery is provided, comprising:

[0059] The housing 1 includes a first housing surface 11 and a second housing surface 12, and an accommodating space is formed between the first housing surface 11 and the second housing surface 12.

[0060] Battery cell 2 is located within the housing space;

[0061] Electrode 3 is electrically connected to battery cell 2 and is adapted to extend from the housing space to the outside of housing 1. Housing 1 has a through portion 13 for electrode 3 to pass through, and electrode 3 is at least partially disposed in the through portion 13.

[0062] The direction in which the electrode sheet 3 is led out is the first direction, the thickness direction of the soft-pack battery is the second direction, and the direction perpendicular to the first and second directions is the third direction.

[0063] A sealing and insulating member 4 is disposed between the electrode sheet 3 and the housing 1, and along the first direction, the sealing and insulating member 4 is at least partially located within the through portion 13;

[0064] The electrode sheet 3 has a notch 31 at at least one end in the third direction, and the notch 31 is connected to the housing 1 through the sealing and insulating member 4; along the second direction, the maximum size of the notch 31 is A mm, and the thickness of the electrode sheet 3 is B mm, satisfying: 0.069≤A / B≤0.889.

[0065] The soft-pack battery involved in this embodiment includes a housing 1, a battery cell 2, and an electrode sheet 3. The housing 1 includes a first housing surface 11 and a second housing surface 12, which are arranged opposite to each other and together form an accommodating space. The battery cell 2 is disposed in the accommodating space and is electrically connected to an external circuit through the electrode sheet 3.

[0066] The electrode sheet 3 can be made of at least one or more of the following materials: aluminum, aluminum alloy, copper, copper-aluminum alloy, steel, stainless steel, nickel, etc., and is used to electrically connect the battery cell inside the housing 1 to other batteries or electrical devices outside.

[0067] The material of the housing 1 may include an aluminum-plastic composite film, and the first housing surface 11 and the second housing surface 12 are formed by folding or encapsulating the same whole aluminum-plastic composite film.

[0068] During assembly, the battery cell 2 is placed between the first housing surface 11 and the second housing surface 12, and the edges of the first housing surface 11 and the second housing surface 12 are heat-sealed to completely cover the battery cell 2 and the non-exposed area of ​​the electrode sheet 3 with the aluminum-plastic composite film. Since the electrode sheet 3 needs to protrude from the housing 1 to conduct electricity with the external circuit, the first housing surface 11 and the second housing surface 12 form a through portion 13 at the corresponding protrusion position of the electrode sheet 3, and the electrode sheet 3 is at least partially disposed in the through portion 13.

[0069] Research has found that in order to increase the current-carrying area of ​​the pouch battery and improve the current rate inside and outside the battery, the thickness of the electrode sheet 3 can be increased to shorten the current-carrying bottleneck of the pouch battery. However, after the thickness of the electrode sheet 3 is increased, the thickness of the pouch battery casing 1 increases when sealing the electrode sheet 3. The fit between the seal and the electrode sheet 3 is not good, resulting in a large gap and an increased risk of sealing failure. When the first casing surface 11 and the second casing surface 12 are packaged, if the edge of the electrode sheet 3 is a right-angle structure, the direction of the pulling force between the first casing surface 11 and the second casing surface 12 at the position of the side of the electrode sheet 3 along the third direction is perpendicular to the bonding plane of the two casing surfaces. This makes the interlayer bonding force of the aluminum-plastic film at this position easy to be damaged, thereby causing interlayer peeling. It is very easy for the electrode sheet 3 to form a sealing gap between the casing 1 due to pulling, resulting in poor sealing.

[0070] To address the aforementioned issues, this embodiment provides a notch 31 at at least one end of the electrode sheet 3 along a third direction. By changing the edge from a right angle to a chamfer, the first housing surface 11 and the second housing surface 12 smoothly fit together along the notch 31 during the hot-press sealing process. This reduces the pulling force between the first housing surface 11 and the second housing surface 12, thereby effectively reducing the risk of interlayer peeling, improving the sealing reliability of the soft-pack battery during long-term use, and preventing electrolyte leakage and external environmental corrosion of the battery cell.

[0071] A sealing insulating member 4 is further provided between the electrode sheet 3 and the housing 1, and the sealing insulating member 4 is at least partially located in the through portion 13 along the first direction; thereby the sealing insulating member 4 fills the gap portion 31 and the through portion 13, further enhancing the sealing effect between the electrode sheet 3 and the housing 1.

[0072] The sealing insulation component 4 can be made of one or more of the following insulating materials: polypropylene (CPP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene succinate (PBS), and polyimide (PI).

[0073] When the thickness B of the electrode sheet 3 is greater, the risk of delamination between the first housing surface 11 and the second housing surface 12 is greater, and the sealing gap 7 is more likely to be generated. In this case, the notch 31 plays a more significant role in mitigating cracking. Conversely, when the thickness B of the electrode sheet 3 is reduced, although the risk of delamination between the first housing surface 11 and the second housing surface 12 is relatively reduced and the sealing gap 7 is less likely to be generated, the current transmission rate also decreases, affecting the overall performance of the battery.

[0074] When the maximum size A of the notch 31 is larger, the fit between the first housing surface 11 and the second housing surface 12 along the chamfered transition area is smoother, the risk of interlayer peeling is lower, and the sealing reliability is improved. However, if the maximum size A of the notch 31 is too large, it will occupy more space and affect the effective conductive area of ​​the electrode sheet. When the maximum size AA of the notch 31 is too small, the fit between the first housing surface 11 and the second housing surface 12 along the chamfered transition area is steeper, the effect of the notch 31 is relatively weakened, the risk of interlayer peeling increases, and the sealing reliability decreases.

[0075] Therefore, the maximum size A of the notch 31 needs to be reasonably matched according to the thickness B of the electrode sheet 3, so as to ensure the sealing reliability while taking into account the conductivity.

[0076] When the A / B ratio is too large, the maximum size A of the notch 31 is too large, which will significantly reduce the effective conductive area of ​​the electrode sheet 3. When the thickness B of the electrode sheet 3 is too small, it will also lead to a decrease in current transmission capacity and affect the battery's fast charging and discharging performance. When the A / B ratio is too small, the maximum size A of the notch 31 is too small, which will cause the first housing surface 11 and the second housing surface 12 to adhere steeply during hot pressing, resulting in stress concentration between layers. This can easily cause the aluminum-plastic film to peel off, reduce sealing reliability, and increase the risk of electrolyte leakage. At the same time, when the thickness B of the electrode sheet 3 is too large, although it helps to improve conductivity, it will also exacerbate the tendency of interlayer peeling during hot pressing and sealing, leading to an increased probability of the formation of the sealing gap 7.

[0077] In this embodiment, along the second direction, the maximum dimension Amm of the notch 31 ranges from 0.1mm ≤ Amm ≤ 0.5mm. The thickness Bmm of the electrode sheet 3 ranges from 0.3mm ≤ Bmm ≤ 1.5mm.

[0078] For example, in this embodiment, the value of A / B can be 0.069 or 0.15 or 0.231 or 0.312 or 0.393 or 0.474 or 0.555 or 0.636 or 0.717 or 0.8 or 0.82 or 0.889, or it can be any range formed by any two of the above values.

[0079] In this embodiment, the direction in which the electrode sheet 3 is led out is the first direction, which can also be the length direction of the soft-pack battery; the thickness direction of the soft-pack battery is the second direction; and the direction perpendicular to the first and second directions is the third direction, which can also be the width direction of the soft-pack battery.

[0080] In some embodiments, the electrode sheet 3 has notches 31 at both ends in the third direction.

[0081] The electrode sheet 3 has a notch 31 at at least one end in the third direction, such as... Figure 8As shown in (e), furthermore, the electrode sheet 3 has notches 31 at both ends in the third direction, as shown in (e). Figure 7 as well as Figure 8 As shown in (a), (b), (c), (d), and (f), stress is dispersed at both ends of the electrode sheet 3 in the third direction, reducing the risk of interlayer peeling in the edge area and improving the sealing reliability of the sealing area. At the same time, the symmetrical arrangement of the notch 31 in the third direction helps to balance the thermal pressure on both sides of the electrode sheet, avoiding deformation or misalignment of the aluminum-plastic film caused by uneven stress, and further ensuring the packaging quality.

[0082] Preferred use Figure 7 As shown in the structure, the electrode sheet 3 has notches 31 at both ends in the third direction, and notches 31 are formed at both corners in the second direction. The notches 31 are specifically chamfered, so that the middle of the electrode sheet 3 can ensure the flow, and the upper and lower surfaces in the second direction are notched, which increases the thickness of the sealing insulation 4 and improves the sealing effect.

[0083] In some embodiments, the size of the notch 31 in the third direction is in the range of N mm, satisfying: 0.1 mm ≤ N mm ≤ 0.5 mm.

[0084] By limiting the range of Nmm values, the sealing effect of the electrode sheet 3 edge can be effectively improved, while ensuring the current carrying capacity of the electrode sheet.

[0085] Furthermore, Nmm = Amm is satisfied.

[0086] For example, in this embodiment, the value of Nmm can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, or 0.5mm, or it can be any range formed by any two of the above values.

[0087] In some embodiments, the size of the third-party upward electrode 3 is J1mm and the size of the housing 1 is J2mm, satisfying: 0.25≤J1 / J2≤0.8; and / or, 20mm≤J1mm≤80mm; and / or, 80mm≤J2mm≤120mm.

[0088] By limiting the upper limit of the J1 / J2 ratio, the size of the electrode sheet 3 in the third direction can be prevented from being too large, and the sealing edge size from the edge of the electrode sheet 3 to the edge of the battery casing 1 can be prevented from being too small, which would make the seal prone to failure. At the same time, by limiting the lower limit of the J1 / J2 ratio, it can be ensured that the electrode sheet 3 has a sufficient effective area to maintain the current carrying capacity of the electrode sheet 3 and avoid insufficient overcurrent capacity due to excessive size.

[0089] For example, in this embodiment, the value of J1 / J2 can be 0.25 or 0.30 or 0.35 or 0.40 or 0.45 or 0.50 or 0.55 or 0.60 or 0.65 or 0.70 or 0.75 or 0.8, or it can be any range formed by any two of the above values.

[0090] In some embodiments, the maximum dimension of the notch 31 at the first end of the electrode sheet 3 in the third direction along the second direction is A1mm, and the maximum dimension of the notch 31 at the second end of the electrode sheet 3 in the third direction along the second direction is A2mm. A1 and A2 satisfy the relationship: |A1mm-A2mm|≤0.2mm.

[0091] The radius (R) of the notches 31 at both ends of the electrode sheet 3 in the third direction can be the same or similar to ensure the uniformity of stress distribution at both ends in the third direction. When there is a difference between A1 and A2, the difference should be controlled within the above range to avoid local stress concentration during hot pressing due to asymmetrical chamfering, which could lead to peeling or poor sealing between the first shell surface 11 and the second shell surface 12, thus ensuring the safety and reliability of the soft-pack battery during long-term use.

[0092] For example, in this embodiment, the value of |A1mm-A2mm| can be 0mm or 0.1mm or 0.12mm or 0.15mm or 0.2mm, or it can be any range formed by any two of the above values.

[0093] In some embodiments, such as Figure 8 As shown in (c), the electrode sheet 3 has a first end face at the first end in the third direction and a second end face at the second end; the corners of the first end face and / or the second end face along the second direction are both constructed as notches 31.

[0094] By further providing notches 31 at the corners of the first and second end faces along the second direction, the interlayer peeling phenomenon of the first shell surface 11 and the second shell surface 12 at the corners during hot-press sealing can be effectively alleviated, thus avoiding the risk of electrolyte leakage caused by sealing defects.

[0095] In some embodiments, a first notch and a second notch are formed at the two corners of the first end face or the second end face along the second direction, respectively. The maximum dimension of the first notch along the second direction is A3mm, and the maximum dimension of the second notch along the second direction is A4mm. A3 and A4 satisfy the relationship: |A3mm-A4mm|≤0.3mm.

[0096] The maximum dimensions of the notches at both ends of the first or second end face along the second direction can be the same or similar to ensure that the stress distribution on both sides in the second direction is symmetrical. When there is a difference between A3 and A4, the difference can be controlled within the above range to avoid uneven local stress during hot pressing due to asymmetrical chamfering, which could lead to delamination of the aluminum-plastic film at the packaging edge or sealing failure.

[0097] For example, in this embodiment, the value of |A3mm-A4mm| can be 0mm or 0.1mm or 0.12mm or 0.15mm or 0.2mm or 0.25mm or 0.3mm, or it can be a range formed by any two of the above values.

[0098] In some embodiments, the thickness of the sealing insulation 4 at the position corresponding to the notch 31 is greater than the thickness at the position corresponding to the non-notch 31.

[0099] By appropriately increasing the thickness of the sealing insulation component 4 in the corresponding notch 31 area, the gap between the two ends of the electrode sheet 3 in the third direction and the housing 1 can be effectively filled, improving the tightness of the interface fit, further suppressing local peeling caused by stress concentration during hot pressing, and improving the sealing effect at the notch 31.

[0100] In this embodiment, the thickness of the sealing insulation component 4 ranges from 0.03mm to 0.2mm.

[0101] In some embodiments, combined with Figure 9 As shown, the electrode sheet 3 includes a first electrode 32 connected to the battery cell 2, and the first electrode 32 extends at least partially beyond the through portion 13 along a first direction.

[0102] The first electrode 32 extends at least partially beyond the through portion 13 along the first direction, meaning that the first electrode 32 is not within the projection range of the through portion 13 in the first direction, thereby avoiding the risk of short circuit between the housing 1 and the battery cell 2 due to positional overlap.

[0103] In some embodiments, combined with Figure 9 As shown, the closest distance between the first electrode 32 and the through portion 13 along the first direction is Cmm, which satisfies: 2mm≤Cmm≤10mm.

[0104] By limiting the range of Cmm values, a sufficient safe distance can be maintained between the first electrode 32 and the through portion 13 to avoid electrical short circuits caused by assembly deviations; at the same time, it can be prevented that excessive distance will increase the overall volume of the battery and affect the energy density.

[0105] For example, in this embodiment, the value of Cmm can be 2mm or 3mm or 3.5mm or 5mm or 6mm or 8mm or 10mm, or it can be a range formed by any two of the above values.

[0106] In some embodiments, the battery cell 2 includes an electrode sheet and a tab extending from the electrode sheet; the electrode sheet 3 is directly electrically connected to the tab.

[0107] In this embodiment, the electrode plate 3 is directly electrically connected to the tab, thereby utilizing the electrode plate 3 as part of the conductive path to achieve external circuit connection between the tab and the cell 2, improving conductivity reliability. This shortens the current transmission path, reduces internal resistance, and improves battery charging and discharging efficiency.

[0108] The electrode sheet 3 can be connected to the tab by welding, riveting or bonding to ensure stable electrical connection and mechanical strength that meets design requirements.

[0109] In some other embodiments, the battery cell 2 includes an electrode sheet, and the electrode sheet 3 is directly electrically connected to the electrode sheet.

[0110] Electrode 3 is directly electrically connected to the electrode plate. In this case, electrode 3 can act as a tab and be directly connected to the external circuit. In this embodiment, electrode 3, as an extension of the electrode plate, is manufactured integrally with the electrode plate and led out to the external circuit, thereby eliminating the need for an additional tab structure and simplifying the assembly process.

[0111] In some embodiments, combined with Figure 3 As shown, the electrode sheet 3 includes a first electrode sheet 301 and a second electrode sheet 302. The first electrode sheet 301 and the second electrode sheet 302 are respectively led out from opposite ends of the housing 1 along the first direction. The first electrode sheet 301 and the second electrode sheet 302 are respectively provided with notches 31.

[0112] The pouch battery has electrode plates 3 extending from both ends of its opposite sides along the first direction, allowing for flexible selection of electrical connection paths when the batteries are assembled. Furthermore, notches 31 are provided on the first electrode plate 301 and the second electrode plate 302, ensuring a good transition effect for the electrode plates 3 extending from both ends of the pouch battery along the first direction. This improves the sealing strength between the casing 1 and the electrode plates 3, reduces the precision requirements for sealing assembly, and avoids poor sealing.

[0113] In some embodiments, the distance between the first electrode plate 301 and the second electrode plate 302 along the first direction is Dmm, which satisfies 270mm≤Dmm≤800mm.

[0114] The distance D between the first electrode plate 301 and the second electrode plate 302 actually reflects the effective length of the cell in the first direction. Reasonably controlling the range of D values ​​can prevent the battery size from becoming too long due to excessive D, which would affect the overcurrent capacity.

[0115] For example, in this embodiment, the value of Dmm can be 270mm or 300mm or 350mm or 400mm or 450mm or 500mm or 550mm or 600mm or 650mm or 700mm or 750mm or 800mm, or it can be a range formed by any two of the above values.

[0116] In some embodiments, the following condition is satisfied: 0.4mm ≤ Bmm ≤ 1.2mm.

[0117] The greater the thickness B of the electrode sheet 3, the greater the risk of interlayer delamination between the first housing surface 11 and the second housing surface 12, and the easier it is to generate a sealing gap 7. In this case, the notch 31 plays a more significant role in mitigating cracking. Conversely, when the thickness B of the electrode sheet 3 decreases, although the risk of interlayer delamination between the first housing surface 11 and the second housing surface 12 is relatively reduced, and it is less likely to generate a sealing gap 7, the current transmission rate also decreases, affecting the overall performance of the battery. Therefore, it is necessary to comprehensively consider the impact of the thickness B of the electrode sheet 3 on sealing performance and conductivity performance, and reasonably set the value range of B to effectively suppress interlayer delamination and the generation of sealing gaps 7 while ensuring current transmission efficiency.

[0118] For example, in this embodiment, the value of Bmm can be 0.4mm or 0.5mm or 0.6mm or 0.7mm or 0.8mm or 0.9mm or 1.0mm or 1.1mm or 1.2mm, or it can be a range formed by any two of the above values.

[0119] In some embodiments, the conductivity rate of the first electrode plate 301 is greater than that of the second electrode plate 302, and the maximum dimension a5mm of the notch 31 of the first electrode plate 301 along the second direction is not equal to the maximum dimension a6mm of the notch 31 of the second electrode plate 302 along the second direction.

[0120] In some embodiments, the following condition is satisfied: a5mm < a6mm.

[0121] The second electrode 302 has a slow conductivity rate and concentrated heat generation. Thermal stress is more likely to accumulate at the chamfer, increasing the risk of seal failure and resulting in poor sealing. Therefore, the R-angle size a6 of the notch of the second electrode 302 is designed to be larger than a5 of the first electrode 301, which can further improve the sealing strength between the second electrode 302 and the housing 1 and avoid sealing differences on both sides of the electrode 3.

[0122] In other embodiments, the following condition is satisfied: a6mm ≤ a5mm. Reducing the size of a6 increases the cross-sectional area of ​​the second electrode plate, thereby increasing the current-carrying capacity of the second electrode plate, and thus improving the overall current-carrying capacity of the battery.

[0123] In some embodiments, the sealing and insulating member 4 is sleeved on the outer periphery of the electrode sheet 3.

[0124] By providing a sealing and insulating component 4 around the outer periphery of the electrode sheet 3, the insulation performance between the electrode sheet and the housing is effectively enhanced, preventing safety hazards caused by partial discharge or short circuit. The sealing and insulating component 4 tightly covers the notch 31 and the adjacent area, further filling the microscopic gap between the housing 1 and the electrode sheet 3, and improving the overall sealing reliability.

[0125] In some embodiments, combined with Figure 5 As shown, the sealing insulating component 4 forms a sealing edge 41 on both sides along the third direction and beyond the electrode plate 3. The width of the sealing edge 41 along the third direction is Emm, which satisfies: 1.5mm≤Emm≤8mm.

[0126] The sealing edge formed by the sealing connection between the first housing surface 11 and the second housing surface 12 of the soft-pack battery is used to seal the battery cell; the sealing connection can be achieved by heat fusion of the inner sealing layer or by adhesive sealing.

[0127] If the width E of the sealing edge 41 along the third direction is too small, the sealing coverage between the housing and the electrode sheet will be insufficient, which may lead to a decrease in sealing reliability. If the width E of the sealing edge 41 along the third direction is too large, it may cause material stacking redundancy and increase the packaging difficulty. Therefore, reasonably controlling the value range of E can ensure that the sealing edge 41 fully covers the bonding area between the housing and the electrode sheet, effectively blocking the electrolyte penetration path, and can also avoid assembly interference caused by material overflow.

[0128] For example, in this embodiment, the value of Emm can be 1.5mm or 2mm or 3mm or 4mm or 5mm or 6mm or 7mm or 8mm, or it can be a range formed by any two of the above values.

[0129] In some embodiments, combined with Figure 10 As shown, the sealing insulating member 4 has a sealing chamfer 42 formed at at least one end along a third direction.

[0130] Since the sealing insulation component 4 is located between the electrode sheet 3 and the housing 1, the first housing surface 11 and the second housing surface 12 are actually in contact with the side of the sealing insulation component 4 along the third direction during encapsulation. If the end of the sealing insulation component 4 along the third direction is a right-angle structure, stress concentration is likely to occur during the press-fitting process, causing the first housing surface 11 and the second housing surface 12 to cause interlayer peeling, thereby forming a sealing gap and resulting in poor sealing.

[0131] By forming a sealing chamfer 42 at at least one end of the sealing insulation member 4 along a third direction, the first housing surface 11 and the second housing surface 12 can smoothly transition along the sealing chamfer 42 during the hot-press sealing process, reducing the mutual pulling force between the first housing surface 11 and the second housing surface 12, thereby effectively reducing the risk of interlayer peeling and improving the sealing reliability of the soft pack battery in long-term use.

[0132] Optionally, the sealing insulation element 4 has sealing chamfered portions 42 formed at both ends along the third direction.

[0133] In some embodiments, combined with Figure 9 As shown, along the first direction, the sealing insulation element 4 extends beyond the outer edge of the housing 1.

[0134] Along the first direction, the sealing and insulating component 4 extends beyond the outer edge of the housing 1, forming a complete protective edging in the area extending beyond the outer edge of the housing 1. This enhances the insulation effect between the electrode sheet 3 and the external environment, further blocking the path of electrolyte penetration along the edge of the housing. The width of the extended portion is reasonably adapted to the encapsulation space, ensuring both the sealing coverage area and the overall assembly accuracy.

[0135] In addition, the sealing insulation component 4 is set beyond the outer edge of the housing 1, which can effectively avoid the impact of housing edge burrs or deformation on the sealing insulation performance, prevent the risk of partial discharge or short circuit caused by edge defects, and improve battery safety and reliability.

[0136] In some embodiments, along the first direction, the length of the sealing insulation 4 extending beyond the outer edge of the housing 1 is F mm, satisfying: 0.5 mm ≤ F mm ≤ 6 mm.

[0137] When the length F of the sealing insulation component 4 extending beyond the outer edge of the housing 1 in the first direction is too small, it is difficult to form an effective edging and cannot fully cover the burrs or micro-uneven areas that may exist on the edge of the housing, resulting in a weakened insulation effect and an increased risk of partial discharge. When F is too large, the sealing insulation component 4 blocks too much area of ​​the electrode sheet 3, affecting heat dissipation. In addition, excessive stacking of materials will also affect the welding area between the electrode sheet 3 and the external structure, thereby reducing the reliability of the connection.

[0138] Therefore, by reasonably controlling the range of F values, both insulation protection and heat dissipation performance can be taken into account, while ensuring effective exposure of the welding area and maintaining the overall structural compactness and manufacturing yield of the battery.

[0139] For example, in this embodiment, the value of Fmm can be 0.5mm or 1mm or 1.5mm or 2mm or 2.5mm or 3mm or 3.5mm or 4mm or 4.5mm or 5mm or 5.5mm or 6mm, or it can be a range formed by any two of the above values.

[0140] In some embodiments, the notch 31 is continuously provided along a first direction.

[0141] By continuously providing notches 31 along the first direction, stress can be effectively guided to distribute evenly, ensuring that notches 31 exist in all areas of the electrode sheet 3 along the first direction. This allows the first housing surface 11 and the second housing surface 12 to smoothly adhere along the notches 31 during the hot-press sealing process, avoiding sealing failure caused by local stress concentration, further improving the structural integrity of the sealing area, effectively reducing the risk of interlayer peeling, and improving the sealing reliability of the soft-pack battery during long-term use.

[0142] In some embodiments, the housing 1 includes at least a three-layer structure consisting of an outer insulating layer 101, a middle metal layer 102, and an inner insulating layer 103.

[0143] Combination Figure 11 As shown, along the second direction, the electrode sheet 3 includes a first end face and a second end face, and the distance from one of them to the intermediate metal layer 102 is Gmm, which satisfies: 0.07mm≤Gmm≤0.3mm.

[0144] The material of the shell 1 may include aluminum-plastic film, which is a flexible packaging material composed of multiple materials. Specifically, it may be a multi-layer film composed of an outer protective layer, an intermediate aluminum foil layer and an inner heat-sealing layer bonded together with an adhesive.

[0145] The outer protective layer serves as the outer insulation layer, and its material can be one or more of the following: polycaprolactam (nylon 6), PET (polyethylene terephthalate), polybutylene succinate, etc.

[0146] The metal layer can be one or more of the following metals or alloys: aluminum, aluminum alloy, copper, nickel, etc.

[0147] The inner heat-sealing layer serves as the inner insulation layer, and its material can be one or more of materials such as polypropylene film (PP) and cast polypropylene film (CPP).

[0148] Since the intermediate metal layer 102 is conductive, when the first or second end face of the electrode sheet 3 is too close to the intermediate metal layer 102, the Gmm is too small, which poses a risk of insufficient insulation gap and may cause an electrical short circuit between the electrode and the metal layer; while if the Gmm is too large, it will lead to redundant casing, reduce space utilization, and affect the battery energy density.

[0149] Specifically, in this embodiment, the thickness of the inner insulating layer 103 ranges from 0.04mm to 0.08mm, and the thickness of the sealing insulating component 4 ranges from 0.03mm to 0.2mm.

[0150] For example, in this embodiment, the value of Gmm can be 0.07mm or 0.08mm or 0.1mm or 0.15mm or 0.2mm or 0.25mm or 0.3mm, or it can be a range formed by any two of the above values.

[0151] In some embodiments, when Bmm satisfies 0.5mm≤Bmm≤1.2mm, Gmm satisfies: 0.08mm≤Gmm≤0.3mm.

[0152] When the thickness B of electrode sheet 3 is larger, it is more necessary to ensure the insulation effect. Therefore, the value of Gmm should be increased appropriately as Bmm increases to ensure sufficient insulation spacing and prevent short circuit risk caused by insufficient electrical clearance due to the increase of electrode sheet thickness. When Bmm is in a smaller range, Gmm can be reduced appropriately to improve space utilization efficiency while ensuring safety.

[0153] In some embodiments, the ratio of the total dimension of the notch 31 along the second direction to the dimension of the electrode sheet 3 in the second direction is 0.1 to 0.9.

[0154] The dimension of the notch 31 along the second direction can be the same as or smaller than the dimension along the thickness direction of the electrode sheet. By limiting the upper limit of the ratio of the total dimension of the notch 31 along the second direction to the dimension of the electrode sheet 3 in the second direction, the dimension of the notch 31 along the second direction is prevented from being too large, which would lead to a narrowing of the width of the electrode sheet 3, a reduction in the current-carrying cross-sectional area, and affect the transmission of external current in the battery, resulting in concentrated heat generation on the electrode sheet. At the same time, by limiting the lower limit of the ratio of the total dimension of the notch 31 along the second direction to the dimension of the electrode sheet 3 in the second direction, the dimension of the notch 31 along the second direction is prevented from being too small, which would lead to an insufficient size of the sealing layer, poor sealing performance of the battery casing, and affect the overall sealing strength of the battery, resulting in cracking of the sealing edge.

[0155] For example, in this embodiment, the ratio of the total size of the notch 31 along the second direction to the size of the electrode sheet 3 in the second direction can be 0.1 or 0.2 or 0.3 or 0.5 or 0.6 or 0.7 or 0.9, or it can be a range formed by any two of the above values.

[0156] In some embodiments, at least one of the first housing surface 11 and / or the second housing surface 12 is formed with a recess for accommodating the battery cell 2.

[0157] At least one of the first housing surface 11 and / or the second housing surface 12 is formed with a pit, which provides a space for the battery cell 2 to be accommodated, and provides a buffer space for the expansion and deformation generated by the battery cell 2 during operation. It can also increase the diffusion path of gas, slow down the accumulation of internal pressure, reduce the risk of local bulging caused by gas accumulation, and thus further avoid sealing failure.

[0158] Optionally, the depth of the pit in the thickness direction is adapted to the thickness of the cell 2.

[0159] In some embodiments, both the first housing surface 11 and the second housing surface 12 are formed with recesses.

[0160] Both the first housing surface 11 and the second housing surface 12 have recesses, which are arranged opposite each other to form a symmetrical structure that encloses the battery cell 2. This improves the uniformity of the overall mechanical distribution and suppresses local stress concentration. It also helps to balance the internal expansion force during battery charge and discharge cycles, ensuring a good seal.

[0161] In some embodiments, a sealing edge is formed on the first housing surface 11 along the outer periphery of the recess, and at least a portion of the sealing edge forms a through portion 13.

[0162] Along the second direction, the portion where the sealing edge and electrode 3 overlap protrudes beyond the portion where the sealing edge and electrode 3 do not overlap.

[0163] The thicker the protrusion, the thicker the electrode sheet 3, and the stronger the current carrying capacity of the electrode sheet 3.

[0164] In some embodiments, combined with Figure 4 As shown, along the second direction, the height difference between the overlapping part of the sealing edge and the non-overlapping part of the electrode 3 and the overlapping part of the sealing edge and the electrode 3 is Hmm, which satisfies: 0.16mm≤Hmm≤1.6mm.

[0165] When the thickness of electrode 3 increases, the current carrying capacity of electrode 3 becomes stronger, and Hmm increases accordingly. However, if Hmm is too large, it may cause stress concentration in the sealing structure and affect the sealing reliability. Therefore, the value range of Hmm needs to be reasonably set according to the actual current carrying capacity of electrode 3 to achieve a performance balance under the premise of ensuring current carrying capacity and sealing reliability. When the thickness of electrode 3 decreases, Hmm should be reduced accordingly to avoid material waste and structural redundancy.

[0166] In this embodiment, the thickness of electrode sheet 3 ranges from 0.3mm to 1.2mm.

[0167] The thickness of the sealing insulation component 4 ranges from 0.03mm to 0.2mm.

[0168] For example, in this embodiment, the value of Hmm can be 0.16mm or 0.2mm or 0.3mm or 0.4mm or 0.5mm or 0.6mm or 0.7mm or 0.8mm or 0.9mm or 1.0mm or 1.1mm or 1.2mm or 1.3mm or 1.4mm or 1.5mm or 1.6mm, or it can be a range formed by any two of the above values.

[0169] In some embodiments, combined with Figure 2 As shown, the housing 1 includes a first sealing edge 141, a second sealing edge 142 and a third sealing edge 143, a through portion 13 is formed on the first sealing edge 141, the second sealing edge 142 and the first sealing edge 141 are disposed opposite to each other, and the third sealing edge 143 is adapted to connect the first sealing edge 141 and the second sealing edge 142.

[0170] The dimension of the third sealing edge 143 extending away from the battery cell 2 is greater than the dimension of the first sealing edge 141 extending away from the battery cell 2.

[0171] In this embodiment, the second sealing edge 142 and the first sealing edge 141 are respectively disposed on opposite sides of the housing 1 along the first housing surface 11, and the third sealing edge 143 is disposed on one side of the housing 1 along a third direction and is connected to the first sealing edge 141 and the second sealing edge 142, forming an enclosing structure for the battery cell 2.

[0172] By making the extension dimension of the third sealing edge 143 larger than that of the first sealing edge 141, the structural strength of the housing edge can be effectively enhanced, and the overall sealing effect can be improved.

[0173] In some embodiments, along the first direction, when the distance between the first sealing edge 141 and the second sealing edge 142 is greater than or equal to 400 mm, the following condition is satisfied: 0.069≤A / B≤0.85.

[0174] When the distance between the first sealing edge 141 and the second sealing edge 142 is greater than or equal to 400mm, that is, when the size of the cell 2 in the first direction is large, the current transmission path between the cell and the electrode sheet is long and the overall resistance of the battery is large. In order to ensure the uniformity of current transmission, the value of A / B needs to be controlled within a reasonable range and the upper limit of the value of A / B should be appropriately lowered to avoid the R angle A of the notch 31 being too large, which will significantly reduce the effective conductive area of ​​the electrode sheet 3. If the thickness B of the electrode sheet 3 is too small, it will also lead to a decrease in current transmission capability and affect the performance of the battery's fast charging and discharging.

[0175] In some embodiments, the chamfer of the notch 31 may be a right angle or a rounded corner, forming an inclined transition surface between two adjacent surfaces by a right angle, or forming an arc-shaped transition surface between two adjacent surfaces by a rounded corner.

[0176] The preparation methods of the pouch cell in each embodiment are as follows:

[0177] (1) Preparation of the positive electrode:

[0178] The positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the positive electrode sheet is obtained. The mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0179] (2) Preparation of negative electrode:

[0180] The negative electrode active material, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0181] (3) Preparation of electrolyte:

[0182] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0183] (4) Preparation of the diaphragm:

[0184] Polyethylene film is selected as the diaphragm.

[0185] (5) Preparation of lithium-ion batteries:

[0186] The positive electrode, separator, and negative electrode are stacked in sequence to form a battery cell. The battery cell is placed in an aluminum-plastic shell, with the inner layer of the aluminum-plastic shell being cast polypropylene (CPP), the middle layer being metallic aluminum, and the outer layer being polycaprolactam (nylon 6). The edges are sealed using a heat sealer, and an electrolyte injection port is reserved. The battery is dried, and then electrolyte is injected. After standing, formation, volume adjustment, and final sealing, a soft-pack battery is obtained.

[0187] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate; the negative electrode active material can be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0188] Along the second direction, the maximum dimension of the notch 31 is A mm, and the thickness of the electrode sheet 3 is B mm. In this embodiment, the testing methods for A and B are as follows: the battery is discharged to the lower limit voltage at 0.33C, and the value of A and the value of B of the electrode sheet thickness in the chamfer direction are measured using a scanning electron microscope. Specifically, when measuring the value of B, five points can be measured in the non-chamfered area of ​​the electrode sheet, and the average value is taken to obtain the value of B.

[0189] When the positive electrode active material of the battery is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V. When the positive electrode active material of the battery is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0190] Referring to Table 1 below, the provided soft-pack battery was subjected to electrode plate temperature rise test and electrode plate leakage test through several embodiments and comparative tests to verify its qualification.

[0191] Performance Test 1: Electrode Plate Temperature Rise Test, the method is as follows:

[0192] For each embodiment and comparative example, 10 identical pouch batteries were used. The pouch battery preparation method is as described above. The A and B values ​​of the electrode plates of the pouch batteries in each embodiment and comparative example are shown in Table 1 below. Apart from this, the remaining structures are the same. The 10 batteries were subjected to charge-discharge tests, and the test methods are as follows:

[0193] At 25℃, the electrode plates are connected to a temperature sensor, and the pouch cells are charged at a constant current rate of 4C until the voltage reaches the upper limit. Then, constant voltage charging is switched until the current drops to 0.05C. The temperature change of the electrode plates is recorded throughout the charging process. The highest temperature of the electrode plates of 10 pouch cells is measured. If the highest temperature T is less than or equal to 45℃, the test result is considered good. If the highest temperature T is greater than 45℃ but less than or equal to 65℃, the test result is considered qualified. If the highest temperature T is greater than 65℃, the test result is considered unqualified.

[0194] Different systems require corresponding adjustments to the upper and lower voltage limits: When the positive electrode active material includes lithium iron phosphate, the upper limit voltage is 3.65V and the lower limit voltage is 2.5V; when the positive electrode active material includes lithium nickel cobalt manganese oxide, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V; when the positive electrode active material includes lithium manganese iron phosphate, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V; when the positive electrode active material includes lithium nickel manganese oxide, the upper limit voltage is 4.8V and the lower limit voltage is 3.5V.

[0195] In this test, the active material for the positive electrode of the pouch battery was selected from lithium nickel cobalt manganese oxide (LiNi). 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0196] Performance Test 2: Electrode Leakage Test, the method is as follows:

[0197] For each embodiment and comparative example, 200 identical pouch batteries were used. The pouch battery preparation method is as described above. The A and B values ​​of the electrode plates of the pouch batteries in each embodiment and comparative example are shown in Table 1 below. Apart from this, the remaining structures are the same. Charge-discharge tests were performed on the 200 batteries, and the test methods are as follows:

[0198] At 25°C, the pouch cells of each embodiment and comparative example were subjected to cyclic testing according to the following procedure, and leakage was tested.

[0199] For pouch cells with lithium iron phosphate as the positive electrode active material:

[0200] 1) Charge at a constant current rate of 1C to 3.65V, and then charge at a constant voltage until the current drops to 0.05C;

[0201] 2) Let it stand for 30 minutes;

[0202] 3) Discharge to 2.5V at a 1C rate;

[0203] 4) Let it stand for 30 minutes;

[0204] Repeat steps 1)-4) for 100 cycles.

[0205] For pouch cells with lithium nickel cobalt manganese oxide as the positive electrode active material:

[0206] 1) Charge at a constant current rate of 1C to 4.35V, and then charge at a constant voltage until the current drops to 0.05C;

[0207] 2) Let it stand for 20 minutes;

[0208] 3) Discharge to 2.75V at a 1C rate;

[0209] 4) Let it stand for 20 minutes;

[0210] Repeat steps 1)-4) for 100 cycles.

[0211] After cycling, the pouch cell was placed in a vibration table and subjected to random vibration in the Z / Y / X directions and sinusoidal fixed-frequency vibration under the conditions of GB38031-2020.8.2. The random vibration in each direction was carried out for 12 hours and the sinusoidal fixed-frequency vibration for 2 hours. Then, it was observed whether there was leakage at the sealing connection between the pouch cell electrode sheet and the aluminum-plastic film shell in each embodiment and comparative example. The number of leaking cells was recorded as n. The percentage of leaking cells was calculated using the formula (n / 200)×100%. If the percentage of leaking cells was less than or equal to 2%, it was considered good. If the percentage of leaking cells was greater than 2% but less than or equal to 5%, it was considered qualified. If the percentage of leaking cells was greater than 5%, it was considered unqualified.

[0212] In this test, the active material for the positive electrode of the pouch battery was selected from lithium nickel cobalt manganese oxide (LiNi). 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0213] Table 1

[0214]

[0215] Regarding the test results, referring to Table 1 above, the explanation is as follows:

[0216] As can be seen from Examples 1-19, when the value of the formula A / B is within the range of 0.069≤A / B≤0.889, the results of the electrode sheet heating test are all good or qualified; the results of the electrode sheet leakage test are all good or qualified, thus meeting the performance requirements.

[0217] In Comparative Examples 1, 2, and 3, the value of the A / B ratio was below the lower limit, resulting in failures in the electrode leakage test and failing to meet performance requirements. In Comparative Example 4, the value of the A / B ratio exceeded the upper limit, leading to failure in the electrode heating test and failing to meet performance requirements.

[0218] According to an embodiment of the present invention, in another aspect, an electrical device is also provided, comprising:

[0219] The main body of the electrical device, and the soft-pack battery as described above that is electrically connected to the main body of the electrical device.

[0220] In this embodiment, the battery can provide electrical energy to the main body of the electrical device, which can be an electronic device, an electric vehicle, or an energy storage system. The electronic device includes a smartphone, a laptop or a tablet computer, the electric vehicle includes an electric car, an electric bicycle or an electric bus, and the energy storage system is used for grid peak shaving, distributed energy storage or emergency power supply.

[0221] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope defined by the present invention.

Claims

1. A soft-pack battery, characterized in that, include: The housing (1) includes a first housing surface (11) and a second housing surface (12), and an accommodating space is formed between the first housing surface (11) and the second housing surface (12); The battery cell (2) is disposed within the accommodating space; The electrode sheet (3) is electrically connected to the battery cell (2) and is adapted to extend from the receiving space to the outside of the housing (1). The housing (1) has a through portion (13) suitable for the electrode sheet (3) to pass through, and the electrode sheet (3) is at least partially disposed in the through portion (13). The direction in which the electrode sheet (3) is led out is the first direction, the thickness direction of the soft-pack battery is the second direction, and the direction perpendicular to the first direction and the second direction is the third direction. A sealing insulating member (4) is disposed between the electrode sheet (3) and the housing (1), and along the first direction, the sealing insulating member (4) is at least partially located within the through portion (13); The electrode sheet (3) has a notch (31) at at least one end in the third direction, and the notch (31) is connected to the housing (1) through the sealing insulation member (4); along the second direction, the maximum size of the notch (31) is A mm, and the thickness of the electrode sheet (3) is B mm, satisfying: 0.069≤A / B≤0.

889.

2. The soft-pack battery according to claim 1, characterized in that, The electrode sheet (3) has notches (31) at both ends in the third direction.

3. The soft-pack battery according to claim 1, characterized in that, The size of the notch (31) in the third direction is N mm, satisfying: 0.1 mm ≤ N mm ≤ 0.5 mm.

4. The soft-pack battery according to claim 2, characterized in that, The maximum dimension of the notch (31) at the first end of the electrode sheet (3) in the third direction along the second direction is A1mm, and the maximum dimension of the notch (31) at the second end of the electrode sheet (3) in the third direction along the second direction is A2mm. A1 and A2 satisfy the relationship: |A1mm-A2mm|≤0.2mm.

5. The soft-pack battery according to claim 1, characterized in that, The electrode sheet (3) has a first end face at the first end in the third direction and a second end face at the second end; the corner of the first end face and / or the second end face along the second direction is constructed as the notch (31).

6. The soft-pack battery according to claim 5, characterized in that, The first end face or the second end face forms a first notch and a second notch at its two corners along the second direction, respectively. The maximum dimension of the first notch along the second direction is A3mm, and the maximum dimension of the second notch along the second direction is A4mm. A3 and A4 satisfy the relationship: |A3mm-A4mm|≤0.3mm.

7. The soft-pack battery according to claim 1, characterized in that, The thickness of the sealing insulation element (4) at the position corresponding to the notch (31) is greater than the thickness at the position not corresponding to the notch (31).

8. The soft-pack battery according to claim 1, characterized in that, The electrode sheet (3) includes a first electrode (32) connected to the battery cell (2), and the first electrode (32) extends at least partially beyond the through portion (13) along the first direction.

9. The soft-pack battery according to claim 8, characterized in that, The closest distance between the first electrode end (32) and the through portion (13) along the first direction is Cmm, which satisfies: 2mm≤Cmm≤10mm.

10. The soft-pack battery according to claim 1, characterized in that, The battery cell (2) includes an electrode and a tab extending from the electrode; the electrode (3) is directly electrically connected to the tab.

11. The soft-pack battery according to claim 1, characterized in that, The battery cell (2) includes an electrode sheet, and the electrode sheet (3) is directly electrically connected to the electrode sheet.

12. The soft-pack battery according to claim 1, characterized in that, The electrode sheet (3) includes a first electrode sheet (301) and a second electrode sheet (302). The first electrode sheet (301) and the second electrode sheet (302) are respectively led out from the housing (1) at opposite ends along the first direction. The first electrode sheet (301) and the second electrode sheet (302) are respectively provided with the notch portion (31).

13. The soft-pack battery according to claim 12, characterized in that, Along the first direction, the distance between the first electrode sheet (301) and the second electrode sheet (302) is Dmm, which satisfies 270mm≤Dmm≤800mm.

14. The soft-pack battery according to claim 13, characterized in that, Satisfies: 0.4mm≤Bmm≤1.2mm.

15. The soft-pack battery according to claim 12, characterized in that, The conductivity of the first electrode (301) is greater than that of the second electrode (302). The maximum dimension a5mm of the notch (31) of the first electrode (301) along the second direction is not equal to the maximum dimension a6mm of the notch (31) of the second electrode (302) along the second direction.

16. The soft-pack battery according to claim 15, characterized in that, Satisfies: a5mm < a6mm.

17. The pouch cell according to any one of claims 1 to 16, characterized in that, The sealing and insulating component (4) is sleeved on the outer periphery of the electrode sheet (3).

18. The soft-pack battery according to claim 17, characterized in that, The sealing insulating member (4) forms a sealing edge (41) on both sides of the third direction and beyond the electrode sheet (3). The width of the sealing edge (41) along the third direction is Emm, which satisfies: 1.5mm≤Emm≤8mm.

19. The soft-pack battery according to claim 17, characterized in that, The sealing insulation member (4) has a sealing chamfer (42) formed at least one end along the third direction.

20. The pouch cell according to any one of claims 1 to 16, characterized in that, Along the first direction, the sealing insulation element (4) extends beyond the outer edge of the housing (1).

21. The soft-pack battery according to claim 20, characterized in that, Along the first direction, the length of the sealing insulation member (4) extending beyond the outer edge of the housing (1) is F mm, satisfying: 0.5 mm ≤ F mm ≤ 6 mm.

22. The pouch cell according to any one of claims 1 to 16, characterized in that, The notch (31) is continuously provided along the first direction.

23. The pouch cell according to any one of claims 1 to 16, characterized in that, The shell (1) comprises at least three layers: an outer insulating layer (101), a middle metal layer (102), and an inner insulating layer (103); Along the second direction, the electrode sheet (3) includes a first end face and a second end face, one of which is at a distance of Gmm from the intermediate metal layer (102), satisfying: 0.07mm≤Gmm≤0.3mm.

24. The soft-pack battery according to claim 23, characterized in that, When Bmm satisfies 0.5mm≤Bmm≤1.2mm, Gmm satisfies: 0.08mm≤Gmm≤0.3mm.

25. The pouch cell according to any one of claims 1 to 16, characterized in that, The ratio of the total dimension of the notch (31) along the second direction to the dimension of the electrode sheet (3) in the second direction is 0.1 to 0.

9.

26. The pouch cell according to any one of claims 1 to 16, characterized in that, At least one of the first housing surface (11) and / or the second housing surface (12) is formed with a recess for accommodating the battery cell (2).

27. The soft-pack battery according to claim 26, characterized in that, The first shell surface (11) and the second shell surface (12) are both formed with the aforementioned pits.

28. The pouch battery according to claim 26, characterized in that, The first housing surface (11) has a sealing edge formed along the outer periphery of the recess, and at least a portion of the sealing edge forms the through portion (13). Along the second direction, the portion of the sealing edge and the electrode sheet (3) that overlaps protrudes beyond the portion of the sealing edge and the electrode sheet (3) that do not overlap.

29. The soft-pack battery according to claim 28, characterized in that, Along the second direction, the height difference between the overlapping portion of the sealing edge and the electrode sheet (3) and the non-overlapping portion of the sealing edge and the electrode sheet (3) is Hmm, satisfying: 0.16mm≤Hmm≤1.6mm.

30. The pouch cell according to any one of claims 1 to 16, characterized in that, The housing (1) includes a first sealing edge (141), a second sealing edge (142) and a third sealing edge (143). The through portion (13) is formed on the first sealing edge (141). The second sealing edge (142) and the first sealing edge (141) are disposed opposite to each other. The third sealing edge (143) is adapted to connect the first sealing edge (141) and the second sealing edge (142). The dimension of the third sealing edge (143) extending away from the battery cell (2) is greater than the dimension of the first sealing edge (141) extending away from the battery cell (2).

31. The soft-pack battery according to claim 30, characterized in that, Along the first direction, when the distance between the first sealing edge (141) and the second sealing edge (142) is greater than or equal to 400mm, the following condition is met: 0.069≤A / B≤0.

85.

32. The pouch cell according to any one of claims 1 to 16, characterized in that, The chamfering form of the notch (31) includes a right angle or a rounded corner, forming an inclined transition surface between two adjacent surfaces by using a right angle, or forming an arc-shaped transition surface between two adjacent surfaces by using a rounded corner.

33. An electrical device, characterized in that, include: The electrical device body, and the pouch battery as described in any one of claims 1 to 32, which is electrically connected to the electrical device body.

Images