Battery cell, battery pack, and insulation method for battery cell

Abstract

The application discloses a battery unit, a battery pack and an insulation processing method of the battery unit. The battery unit comprises a battery shell, a part of an outer surface of the battery shell is covered with a first insulation film, a shell mounting surface of the battery shell is provided with a second insulation film, the shell mounting surface is a side surface of the battery shell facing a bottom plate, 0.83<=(S2xF2) / (S1xF1)<=54, and F2>F1; wherein S1 is an area of the first insulation film on the shell mounting surface; S2 is an area of the second insulation film on the shell mounting surface; F1 is a peeling strength of the first insulation film; and F2 is a peeling strength of the second insulation film. Based on the relationship between the areas and the peeling strengths of the first insulation film and the second insulation film, the application can ensure that the battery unit and the bottom plate have relatively optimal bonding strength on the basis of improving the insulation protection effect, and can also prevent the problem of low insulation film attachment yield.

Description

Technical Field

[0001] This application relates to the field of battery pack technology, and more specifically, to a battery cell, a battery pack, and a method for insulating the battery cell. Background Technology

[0002] A battery cell typically consists of a battery casing and battery cells housed inside the casing. The battery cell is the core component of the battery cell and is composed of a positive electrode, a negative electrode, a separator, and an electrolyte. The battery casing is the outermost protective structure of the battery cell, serving to house and protect the internal components.

[0003] To ensure the safe and stable operation of the battery cell, an insulating film is usually attached to the outside of the battery casing. During the charging and discharging process, the electrodes of the battery cell will carry a high voltage. The insulating film can effectively prevent the current conduction between the battery casing and external conductors, prevent short circuits, and avoid serious safety problems such as battery performance degradation, overheating, or even fire and explosion.

[0004] Battery cells are typically glued to a base plate. An insulating film is glued to the side of the battery cell facing the base plate, but the insulating film does not completely cover the surface of the battery cell facing the base plate, leaving a partially exposed area (called the insulating film window area). Although this arrangement of the insulating film can improve the bonding strength between the battery cell and the base plate by utilizing the window area, it is prone to causing the risk of insulation failure between the battery casing and the base plate.

[0005] Therefore, how to ensure the bonding strength between the battery cell and the base plate while preventing the problem of low bonding yield due to difficulties in rework is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a battery cell that, while ensuring the bonding strength between the battery cell and the base plate, prevents the problem of low bonding yield due to difficulties in rework.

[0007] Another objective of this application is to provide a battery pack having the above-mentioned battery cells, and a method for insulating the above-mentioned battery cells.

[0008] To achieve the above objectives, this application provides the following technical solution:

[0009] The first aspect of this application provides a battery cell for mounting on a base plate, including a battery housing, a portion of the outer surface of the battery housing is covered with a first insulating film, and a second insulating film is provided on the housing mounting surface of the battery housing, the housing mounting surface being the side surface of the battery housing facing the base plate, then 0.83≤(S2×F2) / (S1×F1)≤54, and F2>F1;

[0010] Wherein, S1 is the area of ​​the first insulating film on the mounting surface of the housing, in mm. 2 ;

[0011] S2 represents the area of ​​the second insulating film on the mounting surface of the housing, in mm. 2 ;

[0012] F1 is the peel strength of the first insulating film, in N / mm;

[0013] F2 is the peel strength of the second insulating film, in N / mm.

[0014] The battery cell provided in this application adds a second insulating film to the mounting surface of the battery casing facing the base plate. This arrangement ensures that the mounting surface facing the base plate includes both the first and second insulating films. Areas not covered by the first insulating film are covered by the second insulating film, preventing poor insulation performance due to large areas of exposed areas. In the battery cell disclosed in this application, (S2×F2) / (S1×F1) satisfies: 0.83≤(S2×F2) / (S1×F1)≤54. This avoids the problem of weak adhesion between the battery casing and the base plate and a high risk of vibration failure due to excessively small values ​​in the above formula; it also avoids the problem of difficult repair of the second insulating film and low yield rate of second insulating film coating due to excessively large values ​​in the above formula. Based on the relationship between the area and peel strength of the first and second insulating films, this application can improve the insulation protection effect, ensure better adhesion strength between the battery cell and the base plate, and prevent the problem of low adhesion yield caused by the difficulty of rework of the second insulating film.

[0015] A second aspect of this application provides a battery pack, including a base plate and a battery cell disposed on the base plate, the battery cell being the battery cell described above.

[0016] The battery pack provided in this application has all the technical effects of the aforementioned battery unit, and will not be described in detail here.

[0017] A third aspect of this application provides an insulation treatment method for a battery cell, the battery cell being mounted on a base plate and including a battery casing, the insulation treatment method including a first insulating film pasting step and a second insulating film pasting step;

[0018] The first insulating film pasting step includes: pasting a first insulating film onto the side surface of the battery housing, and extending at least a portion of the edge of the first insulating film to the housing mounting surface, wherein the housing mounting surface is the side surface of the battery housing facing the base plate, and the side surface of the battery housing is the surface of the battery housing connected to the housing mounting surface;

[0019] The second insulating film pasting step includes: pasting the second insulating film on the housing mounting surface, then 0.83≤(S2×F2) / (S1×F1)≤54, and F2>F1;

[0020] Wherein, S1 is the area of ​​the first insulating film on the mounting surface of the housing, in mm. 2 ;

[0021] S2 represents the area of ​​the second insulating film on the mounting surface of the housing, in mm. 2 ;

[0022] F1 is the peel strength of the first insulating film, in N / mm;

[0023] F2 is the peel strength of the second insulating film, in N / mm.

[0024] The battery cell insulation treatment method provided in this application involves attaching a second insulating film with greater peel strength to the housing mounting surface of the battery casing facing the base plate, while extending at least a portion of the edge of the first insulating film to the housing mounting surface. This ensures that the housing mounting surface facing the base plate includes both the first and second insulating films. Areas not covered by the first insulating film can be covered by the second insulating film, preventing poor insulation performance caused by large-area exposure of the uncovered areas. The expression S2×F2) / (S1×F1) satisfies: 0.83≤(S2×F2) / (S1×F1)≤54. This avoids the problem of weak adhesion between the battery casing and the base plate and a high risk of vibration failure due to excessively small values ​​of the above expression; it also avoids the problem of difficult rework of the second insulating film and low yield rate of covering the second insulating film due to excessively large values ​​of the above expression. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the battery cell installed inside the battery box according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the structure of the battery cell disclosed in the embodiments of this application;

[0028] Figure 3 This is a partial cross-sectional view of a battery cell mounted on a base plate, as disclosed in an embodiment of this application.

[0029] Figure 4 This is a front view of the housing mounting surface disclosed in the embodiments of this application;

[0030] Figure 5 This is a front view of the housing mounting surface disclosed in another embodiment of this application;

[0031] Figure 6 This is a partial cross-sectional view of a battery cell mounted on a base plate, as disclosed in another embodiment of this application.

[0032] Figure 7 This is a partial cross-sectional view of a battery cell mounted on a base plate, as disclosed in another embodiment of this application.

[0033] The meanings of the various reference numerals in the figure are as follows:

[0034] 1-Battery cell; 110-Battery casing; 120-First insulating film; 130-Second insulating film; 140-Adhesive layer; 150-Terminal assembly;

[0035] 2-Battery housing; 200-Base plate. Detailed Implementation

[0036] This application discloses a battery cell to ensure the bonding strength between the battery cell and the base plate while preventing the problem of low bonding yield due to difficulty in rework.

[0037] This application also discloses a battery pack having the above-mentioned battery cells, and a method for insulating the above-mentioned battery cells.

[0038] Hereinafter, embodiments will be described with reference to the accompanying drawings. Furthermore, the embodiments shown below do not limit the scope of the application as described in the claims. Additionally, the complete composition represented in the embodiments below is not limited to what is necessary as the solution to the application described in the claims. It should be noted that, for ease of description, only the parts relevant to the application are shown in the drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0039] like Figure 1 and Figure 2As shown, in practical applications of the battery pack, to ensure the stability of the battery cell 1, it is usually necessary to glue the battery cell 1 to the base plate 200 of the battery box 2. It should be noted that the base plate 200 is not limited to the base plate of the battery box 2; that is, the battery pack may also be installed without a battery box 2, and the battery cell 1 may be directly placed in the corresponding space of the vehicle chassis. In this case, the base plate 200 of the battery pack becomes part of the vehicle. In this embodiment, the part used to support the battery cell 1 is referred to as the base plate 200.

[0040] To ensure the safe and stable operation of battery unit 1, an insulating film is attached to the outside of battery housing 110. For ease of understanding, in the installed state of battery unit 1, the surface of battery housing 110 facing the base plate 200 is defined as the housing mounting surface.

[0041] Currently, to ensure the bonding strength between battery cell 1 and base plate 200, the insulating film is usually only wrapped around the edge of the housing mounting surface, so that the part of the housing mounting surface not covered by the insulating film can obtain better bonding strength. Although the adhesive used to bond battery cell 1 also has a certain insulating property, the insulating property is limited, and the adhesive layer is easily squeezed and deformed under external force. Since the area of ​​the part not covered by the insulating film is large, there is a risk of insulation failure.

[0042] To reduce the risk of insulation failure, existing technologies employ an insulating film covering method, where the entire mounting surface of the casing is covered with an insulating film. Since the entire mounting surface is covered with an insulating film, it offers superior insulation performance. However, because the portion bonded between the battery cell 1 and the base plate 200 is actually the insulating film, not the battery casing 110, there are two adhesive layers between the battery cell 1 and the base plate 200: one is an adhesive layer between the insulating film and the base plate 200, and the other is the adhesive backing of the insulating film. The adhesive strength between the battery cell 1 and the base plate 200 is affected by the adhesive backing of the insulating film. Typically, the adhesive strength of the adhesive backing is less than that of the adhesive layer. When the battery pack is exposed to vibration, delamination can easily occur between the battery casing 110 and the insulating film. This results in the battery casing 110 and its internal components, such as the battery cells, partially detaching from the insulating film, inevitably leading to shaking and affecting the safety of the battery pack.

[0043] To prevent delamination between the battery casing 110 and the insulating film, a strong adhesive insulating film is usually selected to reduce the risk of delamination in a vibration environment. However, if the adhesive strength between the insulating film and the battery casing 110 is too high, it will be difficult to adjust the position if there is an assembly deviation in the insulating film, which will affect the production yield of the battery cell 1.

[0044] The applicant discovered through research that existing insulating film coating methods cannot simultaneously achieve optimal insulation performance, adhesive strength, and production yield. Based on this, this application discloses a battery cell 1 that can improve the production yield of the battery cell 1 while ensuring superior insulation performance and adhesive strength.

[0045] In addition, the applicant's research found that in order to improve the bonding strength, it is inevitable that the insulating film will deviate and be difficult to adjust its position, which in turn leads to a decrease in production yield. It is necessary to find a balance between bonding strength and production yield.

[0046] like Figure 2 and Figure 3 As shown in the embodiment of this application, the battery unit 1 is used to be disposed on the base plate 200. The base plate 200 is not limited to the base plate of the battery box 2, but can be any part used to support the battery unit 1 and to bond and fix the battery unit 1.

[0047] The battery cell 1 disclosed in this application includes a battery housing 110, and a battery cell is typically disposed inside the battery housing 110. A terminal assembly 150 is generally disposed on the battery housing 110, and the terminal assemblies 150 of two battery cells can be electrically connected via conductive components.

[0048] The terminal assembly 150 generally includes a positive terminal assembly and a negative terminal assembly. When two battery cells 1 are connected in series, the conductive component needs to electrically connect the positive terminal assembly of one battery cell 1 and the negative terminal assembly of the other battery cell 1, respectively. When two battery cells 1 are connected in parallel, the conductive component needs to electrically connect the terminal assemblies of the same polarity of the two battery cells 1, respectively. The battery cell has a positive tab and a negative tab. The positive tab is electrically connected to the positive terminal assembly of the battery casing, and the negative tab is electrically connected to the negative terminal assembly of the battery casing. The terminal assembly 150 (positive and negative terminal assemblies) is an important component connecting the battery cell 1 to the external circuit. It can transfer the electrical energy generated by the battery cell to the external circuit, and simultaneously introduce electrical energy from the external circuit into the battery cell for charging, acting as a bridge for current conduction.

[0049] The battery cell is the core component of battery unit 1, consisting of a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode is typically made of materials such as lithium cobalt oxide, lithium manganese oxide, or lithium iron phosphate; the negative electrode is generally made of materials such as graphite; the separator is a thin film with a microporous structure, located between the positive and negative electrodes, which isolates the positive and negative electrodes to prevent short circuits; the electrolyte is an organic solution containing lithium salts, responsible for conducting lithium ions between the positive and negative electrodes.

[0050] The battery casing 110 is the outermost protective structure of the battery cell 1, serving to house and protect internal components (such as the battery cells). Common types include square, cylindrical, and pouch cells. The main function of the battery casing 110 is to prevent harmful substances such as moisture and oxygen from entering the interior, avoiding damage to the battery cells, protecting the internal battery cells and other components from external physical impacts and chemical corrosion, and ensuring the safety and stability of the battery cell 1.

[0051] A portion of the outer surface of the battery casing 110 is covered with a first insulating film 120. Typically, the exposed metal portions of the battery casing 110 require insulation protection. The first insulating film 120 is a common insulation treatment method. Those skilled in the art can select appropriate surfaces of the battery casing 110 and perform insulation treatment by covering them with the first insulating film 120, according to their needs. The first insulating film 120 is mainly used to insulate other surfaces of the battery casing 110 (referring to surfaces other than the casing mounting surface). A portion of the edge of the first insulating film 120 may extend to the casing mounting surface. The area of ​​the first insulating film 120 on the casing mounting surface is S1, in mm. 2 .

[0052] A second insulating film 130 is provided on the mounting surface of the battery housing 110. The mounting surface is the side of the battery housing 110 facing the base plate 200, which is also the side of the battery housing 110 used for bonding with the base plate 200. The area of ​​the second insulating film 130 on the mounting surface is S2, in mm. 2 .

[0053] The insulating area formed by the first insulating film 120 and the second insulating film 130 can cover the entire area of ​​the housing mounting surface. That is, any area of ​​the housing mounting surface can be covered by at least one of the first insulating film 120 and the second insulating film 130. Under the coverage of the first insulating film 120 and the second insulating film 130, there are no exposed metal parts on the housing mounting surface, so as to ensure the insulation protection effect.

[0054] Those skilled in the art will understand that the area of ​​the housing mounting surface not covered by the first insulating film 120 may not be completely covered by the second insulating film 130. That is, the insulating area composed of the first insulating film 120 and the second insulating film 130 may not completely cover the entire area of ​​the housing mounting surface. As long as the area not covered by the first insulating film 120 is provided with the second insulating film 130, a better insulation protection effect can be obtained compared with the prior art where the first insulating film 120 is only provided at the edge of the housing mounting surface.

[0055] The first insulating film 120 and the second insulating film 130 have different peel strengths. As adhesive-backed insulating tapes, the peel strength of the first insulating film 120 and the second insulating film 130 is an important indicator for measuring their performance under specific stress conditions. The peel strength of the first insulating film 120 and the second insulating film 130 refers to the peel strength of the insulating film after it has been adhered to a surface, when a peeling force is applied along a direction perpendicular to the adhesive surface, causing it to peel vertically. Peel strength (N / mm) = peel force (N) ÷ width of insulating film (mm). The peel strength of the first insulating film 120 is F1, and the peel strength of the second insulating film 130 is F2, where F2 > F1.

[0056] The first insulating film 120 can be made of one of polyethylene terephthalate, polyimide, polypropylene, and acrylic adhesive; the second insulating film 130 can be made of polyethylene terephthalate, polyimide, polypropylene, or acrylic adhesive. The first insulating film 120 and the second insulating film 130 can be made of the same material or different materials. Those skilled in the art can select the specific materials for the first insulating film 120 and the second insulating film 130 according to insulation requirements. This embodiment does not limit the specific materials of the first insulating film 120 and the second insulating film 130.

[0057] In this embodiment, a second insulating film 130 with greater peel strength is provided on the area of ​​the housing mounting surface not covered by the first insulating film 120 to prevent poor insulation performance caused by large-area exposure of the area not covered by the first insulating film 120. Furthermore, the second insulating film 130 can directly participate in the bonding between the base plates 200, achieving greater bonding strength compared to the area where the first insulating film 120 is located. This is because the peel strength of the second insulating film 130 is greater than that of the first insulating film 120, meaning the bonding strength between the second insulating film 130 and the housing mounting surface is greater than that between the first insulating film 120 and the housing mounting surface. Compared to the first insulating film 120, the second insulating film 130 is less prone to detachment from the housing mounting surface in a vibration environment. After the battery unit 1 is bonded to the base plate 200, it is less likely that the battery unit 1 will wobble relative to the base plate 200 due to detachment of the battery housing 110's housing mounting surface from the second insulating film 130, thus improving the bonding strength between the battery unit 1 and the base plate 200.

[0058] Compared to covering the entire area of ​​the housing mounting surface only with the first insulating film 120, in this embodiment, a second insulating film 130 with greater peel strength is covered on a portion of the housing mounting surface. If the second insulating film 130 has adhesion deviations and needs to be repaired, although the second insulating film 130 has greater peel strength, it is also easier to peel off because the area covered by the second insulating film 130 is smaller, and the second insulating film 130 is less likely to deform or be damaged during peeling. If the first insulating film 120 has adhesion deviations and needs to be repaired, although the first insulating film 120 covers a large area of ​​the side surface of the battery housing 110, the first insulating film 120 has lower peel strength and is easier to peel off, allowing for re-attachment of the first insulating film 120. This prevents the problem of low adhesion yield caused by the difficulty in repairing the first insulating film 120 and the second insulating film 130.

[0059] In this embodiment, (S2×F2) / (S1×F1) satisfies: 0.83≤(S2×F2) / (S1×F1)≤54. That is, based on the relationship between the area and peel strength of the first insulating film 120 and the second insulating film 130, it is possible to improve the insulation protection effect, ensure better bonding strength between the battery cell 1 and the base plate 200, and prevent the problem of low adhesion yield of the second insulating film 130 due to the difficulty of rework.

[0060] For example, the value of (S2×F2) / (S1×F1) can be: 0.83, 1.5, 3.5, 5.5, 8.5, 12.5, 15, 18.5, 21, 24.5, 27.5, 30, 33, 35.5, 38, 40, 43, 45, 48, 50, 53, 54, etc. This embodiment does not limit the specific value of (S2×F2) / (S1×F1), and those skilled in the art can choose the specific value of (S2×F2) / (S1×F1) based on their needs.

[0061] In this embodiment, when (S2×F2) / (S1×F1) satisfies: 0.83≤(S2×F2) / (S1×F1)≤54, the problem of weak bonding strength between the battery casing 110 and the base plate 200 and high risk of vibration failure due to the value of the above relationship being too small can be avoided; it can also avoid the problem of difficulty in repairing the second insulating film 130 and low yield of covering the second insulating film 130 due to the value of the above relationship being too large.

[0062] Simply selecting the parameter S2 (the area of ​​the second insulating film 130 on the housing mounting surface) within a certain range cannot achieve the effect of both ensuring the bonding strength between the battery cell 1 and the base plate 200 and preventing low bonding yield due to rework difficulties. This is because, although increasing the value of S2 can improve the bonding strength between the battery cell 1 and the base plate 200 to a certain extent, if the peel strength F2 of the second insulating film 130 is too small, it may not be able to guarantee the bonding strength between the battery cell 1 and the base plate 200, and may even reduce the bonding strength between the battery cell 1 and the base plate 200 due to F2 being too small.

[0063] Correspondingly, reducing the value of S2 can facilitate the peeling of the second insulating film 130 to some extent and improve the adhesion yield. However, if the peel strength F2 of the second insulating film 130 is too large, it may not guarantee the ease of peeling the second insulating film 130, and may even cause damage to the second insulating film 130 during peeling due to excessively large F2, thus affecting the adhesion yield. In addition, if S1 and F1 also have large values, it may further increase the difficulty of peeling the insulating film on the housing mounting surface.

[0064] Based on this, in this embodiment, (S2×F2) / (S1×F1) satisfies: 0.83≤(S2×F2) / (S1×F1)≤54. That is, based on the relationship between the area and peel strength of the first insulating film 120 and the second insulating film 130, it is possible to improve the insulation protection effect, ensure better bonding strength between the battery cell 1 and the base plate 200, and prevent the problem of low adhesion yield of the second insulating film 130 due to the difficulty of rework.

[0065] The ratio S2 / S1, which is the area S2 of the second insulating film 130 on the housing mounting surface and the area S1 of the first insulating film 120 on the housing mounting surface, ranges from 0.5 to 4. For example, S2 / S1 can be 0.5, 0.8, 1.0, 1.3, 1.6, 1.9, 2.2, 2.5, 2.8, 3.0, 3.3, 3.5, 3.8, 4.0, etc. This embodiment does not limit the specific value of S2 / S1; those skilled in the art can select the above values ​​based on the requirements of adhesive strength and ease of peeling.

[0066] The area S1 of the first insulating film 120 on the mounting surface of the housing is 770 mm². 2 ~24225mm 2 For example, S1 can be 770mm. 2 970mm 2 1270mm 2 1770mm 2 2370mm 2 3000mm2 3848mm 2 5000mm 2 6500mm 2 8000mm 2 9500mm 2 11000mm 2 13000mm 2 15500mm 2 18000mm 2 20000mm 2 21500mm 2 23000mm 2 24225mm 2 It should be noted that the value of S1 is related to the size of the battery cell 1. The larger the size of the battery cell 1, the larger the value of S1 can be. In this embodiment, the area S1 of the first insulating film 120 on the housing mounting surface is not limited.

[0067] Correspondingly, the area S2 of the second insulating film 130 on the housing mounting surface is 380 mm². 2 ~96900mm 2 For example, S2 can be 380mm. 2 600mm 2 980mm 2 1460mm 2 1870mm 2 2580mm 2 3400mm 2 4848mm 2 6000mm 2 8500mm 2 11000mm 2 14000mm 2 18000mm 2 21500mm 2 24225mm 2 31500mm 2 36500mm 2 41500mm 2 51500mm 2 62000mm 2 71500mm 2 82000mm 2 96900mm 2It should be noted that the value of S2 is related to the size of the battery cell 1. The larger the size of the battery cell 1, the larger the value of S2 can be. In this embodiment, the area S2 of the second insulating film 130 on the housing mounting surface is not limited.

[0068] In a specific embodiment of this application, the peel strength F1 of the first insulating film 120 can be 0.2 N / mm to 0.9 N / mm. For example, the peel strength F1 of the first insulating film 120 can be 0.2 N / mm, 0.25 N / mm, 0.3 N / mm, 0.35 N / mm, 0.4 N / mm, 0.45 N / mm, 0.5 N / mm, 0.55 N / mm, 0.6 N / mm, 0.65 N / mm, 0.7 N / mm, 0.75 N / mm, 0.8 N / mm, 0.85 N / mm, 0.9 N / mm, etc. Those skilled in the art can choose the specific value of F1 based on their needs; this embodiment does not limit the specific value of F1.

[0069] The peel strength F2 of the second insulating film 130 can be from 0.5 N / mm to 3 N / mm. For example, the peel strength F2 of the second insulating film 130 can be 0.5 N / mm, 0.55 N / mm, 0.6 N / mm, 0.65 N / mm, 0.7 N / mm, 0.75 N / mm, 0.8 N / mm, 0.85 N / mm, 0.9 N / mm, 1 N / mm, 1.3 N / mm, 1.6 N / mm, 2 N / mm, 2.2 N / mm, 2.5 N / mm, 2.7 N / mm, 3 N / mm, etc. Those skilled in the art can choose the specific value of F2 based on requirements, as long as F2 > F1. This embodiment does not limit the specific value of F2.

[0070] The peel strength of the first insulating film 120 and the second insulating film 130 both affect the bonding performance and production yield of the battery cell 1. Those skilled in the art can select the peel strength of the first insulating film 120 and the second insulating film 130 according to the requirements of the bonding performance and production yield of the battery cell 1.

[0071] like Figure 3As shown in a specific embodiment of this application, on the housing mounting surface of the battery housing 110, at least one edge of the second insulating film 130 has a gap with the corresponding edge of the housing mounting surface. That is, at least one edge of the second insulating film 130 does not cover the corresponding edge of the housing mounting surface. The gap can be set between the edges of several sides of the second insulating film 130 and the corresponding edges of the housing mounting surface, or the gap can be set between the edge of any side of the second insulating film 130 and the corresponding edge of the housing mounting surface. It should be noted that if one edge of the second insulating film 130 is defined as the target edge, then the edge of the corresponding side of the housing mounting surface is the edge of the housing mounting surface closest to the target edge. The corresponding side of the housing mounting surface mentioned later also refers to the side closest to the target edge of the second insulating film 130, and will not be elaborated further below.

[0072] Taking a rectangular structure as an example, at least one side of the second insulating film 130 extends to the corresponding side of the housing mounting surface, forming an exposed area. This exposed area refers to the region where the second insulating film 130 is not adhered. Before the first insulating film 120 is adhered, the metal material of the housing in this exposed area is exposed. Those skilled in the art can select the location and area of ​​the exposed area according to design requirements. The distance between each side edge of the second insulating film 130 and the corresponding side edge of the housing mounting surface can be designed to be equal or unequal. This embodiment does not limit the specific location and area of ​​the exposed area. An exposed area can be provided between the edge of any side of the second insulating film 130 and the corresponding side edge of the housing mounting surface, or an exposed area can be provided between the edges of some sides of the second insulating film 130 and the corresponding side edge of the housing mounting surface.

[0073] If the first insulating film 120 and the second insulating film 130 can cover the entire area of ​​the housing mounting surface, then the exposed area not covered by the second insulating film 130 needs to be covered by the first insulating film 120. That is, a portion of the first insulating film 120 will be directly bonded to the exposed area of ​​the housing mounting surface. The first insulating film 120 can be bonded only to the exposed area, or it can be partially bonded to the exposed area and partially bonded to the second insulating film 130. Since bonding to the second insulating film 130 will form an overlapping area of ​​the first insulating film 120 and the second insulating film 130, and the overlapping area has a larger insulating film thickness, the first insulating film 120 bonded only to the exposed area can achieve a better heat dissipation effect compared to bonding to the second insulating film 130.

[0074] In this embodiment, the second insulating film 130 is not directly bonded to the edge of the housing mounting surface. Instead, a portion of the surface is left exposed, allowing a portion of the first insulating film 120 extending onto the housing mounting surface to be directly bonded to the exposed area (i.e., directly bonded to the housing mounting surface). This ensures that the first insulating film 120 extending onto the housing mounting surface achieves good adhesive strength and prevents the first insulating film 120 from detaching. Furthermore, in addition to being bonded to the exposed area, the first insulating film 120 extending onto the housing mounting surface can also partially cover the second insulating film 130.

[0075] like Figure 6 As shown, in a specific embodiment of this application, at least one edge of the second insulating film 130 can be extended to the edge of the corresponding side of the housing mounting surface, that is, the edge of at least one side of the second insulating film 130 is designed to be flush with the edge of the corresponding side of the housing mounting surface. For example, one or both edges of the second insulating film 130 can be extended to the edge of the corresponding side of the housing mounting surface, or the edge of either side of the second insulating film 130 can be extended to the edge of the corresponding side of the housing mounting surface, that is, the second insulating film 130 covers the entire surface of the housing mounting surface.

[0076] In this embodiment, at least one edge of the second insulating film 130 is extended to the edge of the corresponding side of the housing mounting surface, so that the entire side covers the second insulating film 130 and there is no area on the side not covered by the second insulating film 130. This side edge can obtain double insulation protection from the first insulating film 120 and the second insulating film 130, and can achieve a better insulation protection effect.

[0077] like Figure 4 and Figure 5 As shown in a specific embodiment of this application, the battery unit 1 can be a prismatic battery unit, the battery housing 110 has a cuboid structure, and the housing mounting surface has a rectangular structure. To improve the insulation protection effect, a portion of the edge of the first insulating film 120 needs to extend to the housing mounting surface. The first insulating film 120 extending to the housing mounting surface may overlap with the second insulating film 130 on the housing mounting surface, or it may not overlap.

[0078] Those skilled in the art will understand that the area of ​​the second insulating film 130 on the housing mounting surface and the peel strength of the second insulating film 130 can affect the adhesive strength and adhesion yield of the second insulating film 130. That is, the larger the area of ​​the second insulating film 130 on the housing mounting surface, the greater the peel strength, and thus the greater the adhesive strength, but the peeling difficulty is also greater, resulting in a poorer adhesion yield. The smaller the area of ​​the second insulating film 130 on the housing mounting surface, the lower the peel strength, and thus the lower the adhesive strength, but the peeling difficulty is also easier, resulting in a better adhesion yield.

[0079] If the second insulating film 130 cannot cover the entire area of ​​the housing mounting surface, it will affect the insulation protection effect of the battery unit 1. Therefore, in order to ensure the insulation protection effect of the battery unit 1, a portion of the edge of the first insulating film 120 can be extended to the housing mounting surface to improve the insulation protection effect of the battery unit 1.

[0080] In this embodiment, at least two relatively long edges of the housing mounting surface can be covered with a first insulating film 120 (e.g., Figure 4 (As shown). Alternatively, all four sides of the housing mounting surface can be covered with a first insulating film 120 (e.g., Figure 5 (As shown). When the second insulating film 130 cannot cover the entire area of ​​the housing mounting surface, covering the housing mounting surface with the first insulating film 120 can increase the insulation protection area and improve the insulation protection effect.

[0081] like Figure 3 As shown in a specific embodiment of this application, on the housing mounting surface, the first insulating film 120 is flush with at least one edge of the second insulating film 130. For example, the second insulating film 130 has a rectangular structure, and the first insulating film 120 and the second insulating film 130 can be aligned with one side, or multiple sides of the first insulating film 120 and the second insulating film 130 can be aligned, or the edges of either side of the first insulating film 120 and the second insulating film 130 can be flush with each other.

[0082] In this embodiment, the first insulating film 120 is flush with at least one edge of the second insulating film 130, so that there is no exposed metal area in the flush-joined area of ​​the first insulating film 120 and the second insulating film 130, thus eliminating the risk of short circuit. Moreover, the flush-joined first insulating film 120 and the second insulating film 130 ensure no overlapping area in the thickness direction, which is beneficial for heat dissipation of the battery cell 1.

[0083] In this embodiment, a portion of the side edge of the second insulating film 130 can be flush with the first insulating film 120, and the other side edges of the second insulating film 130 can be arranged in an overlapping area with the first insulating film 120, or arranged at intervals. This embodiment does not limit the relative arrangement between the second insulating film 130 and the first insulating film 120.

[0084] like Figure 6 and Figure 7As shown, the first insulating film 120 and the second insulating film 130 may have overlapping areas on the mounting surface of the housing. In this embodiment, the first insulating film 120 and the second insulating film 130 are provided with overlapping areas at their edges, so that there are no exposed metal areas at the edges of the second insulating film 130, thus improving the insulation protection effect. Compared with the structure where the first insulating film 120 and the second insulating film 130 are flush with each other at their edges, the overlapping area provides a better insulation protection effect. Furthermore, flush joining requires high bonding precision and can easily lead to insulation protection failure due to ineffective flushing at the joint.

[0085] It should be noted that some edges of the second insulating film 130 may overlap with the first insulating film 120, or all edges of the second insulating film 130 may overlap with the first insulating film 120.

[0086] Those skilled in the art can select the positions of the overlapping area and the flush-joining area according to the requirements of insulation protection and heat dissipation. For example, when the requirement for insulation protection is greater than the requirement for heat dissipation in a certain area of ​​the housing mounting surface, then the second insulating film 130 and the first insulating film 120 can be set as overlapping areas in that area; when the requirement for heat dissipation is greater than the requirement for insulation protection in a certain area of ​​the housing mounting surface, then the second insulating film 130 and the first insulating film 120 can be set as flush-joining areas in that area.

[0087] like Figure 6 As shown, in the overlapping area, the first insulating film 120 can be located on the side of the second insulating film 130 facing away from the housing mounting surface. That is, when attaching the first insulating film 120 and the second insulating film 130, the second insulating film 130 can be attached to the housing mounting surface first, and then the first insulating film 120 can be attached to other surfaces of the battery housing 110, so that a portion of the structure of the first insulating film 120 extends to the housing mounting surface, allowing the first insulating film 120 to cover the second insulating film 130.

[0088] In this embodiment, in the overlapping area, the first insulating film 120 is covered over the second insulating film 130, so that the second insulating film 130 can be completely adhered to the housing mounting surface. When the battery unit 1 and the base plate 200 are bonded together by the adhesive layer 140, since the entire area of ​​the second insulating film 130 is bonded to the housing mounting surface, the second insulating film 130 has a larger effective bonding area. Furthermore, the peel strength of the second insulating film 130 is greater than that of the first insulating film 120. Therefore, this method can improve the bonding strength between the battery unit 1 and the base plate 200.

[0089] like Figure 7As shown, in the overlapping area, the second insulating film 130 can also be located on the side of the first insulating film 120 facing away from the housing mounting surface. That is, when attaching the first insulating film 120 and the second insulating film 130, the first insulating film 120 can be first attached to other surfaces of the battery housing 110 (i.e., surfaces other than the housing mounting surface), such that a portion of the structure of the first insulating film 120 extends onto the housing mounting surface. Then, the second insulating film 130 is attached to the housing mounting surface, so that the second insulating film 130 can cover the first insulating film 120.

[0090] In this embodiment, in the overlapping area, the second insulating film 130 covers the first insulating film 120, so that the edge of the second insulating film 130 is not directly pasted to the battery casing 110, but is pasted to the first insulating film 120. Since the first insulating film 120 has weaker adhesion than the second insulating film 130, the edge of the first insulating film 120 is more likely to peel off and form an edge opening; while the second insulating film 130 has stronger adhesion. By covering the edge of the first insulating film 120 with the second insulating film 130, the edge opening of the first insulating film 120 can be prevented, thereby preventing the adhesive layer 140 from overflowing between the first insulating film 120 and the battery casing 110, which would affect the reliability of the battery cell 1 installation.

[0091] In a specific embodiment of this application, the thickness of the first insulating film 120 can be 80μm to 250μm. For example, the thickness of the first insulating film 120 can specifically be: 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, etc.

[0092] The thickness of the second insulating film 130 can be from 80μm to 250μm. For example, the specific thickness of the second insulating film 130 can be: 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, etc.

[0093] The thickness of the first insulating film 120 and the second insulating film 130 both affect the heat dissipation and insulation protection effects of the battery cell 1. Those skilled in the art can select the thickness of the first insulating film 120 and the second insulating film 130 according to the heat dissipation and insulation protection requirements of the battery cell 1. In this embodiment, the thickness of the first insulating film 120 and the second insulating film 130 is controlled within the range of 80μm to 250μm. This avoids the problem of excessive height of the battery cell 1 due to excessive thickness of the first insulating film 120 and the second insulating film 130, which would affect battery stability. Furthermore, excessive thickness of the first insulating film 120 and the second insulating film 130 does not significantly improve insulation performance. It also avoids the problem of poor insulation effect and insulation failure due to insufficient thickness of the first insulating film 120 and the second insulating film 130.

[0094] In a specific embodiment of this application, the hardness of the battery casing 110 is HB20 to HB100, that is, the Brinell hardness of the battery casing 110 is 20 to 100. In this embodiment, a material with a hardness in the range of HB20 to HB100 is selected to prepare the battery casing 110, so that the battery casing 110 has high hardness and less deformation. Therefore, the force exerted on the first insulating film 120 and the second insulating film 130 by the deformation of the battery casing 110 is also smaller, which can improve the service life of the first insulating film 120 and the second insulating film 130 and avoid the problem of insulation protection failure caused by the deformation and damage of the first insulating film 120 and the second insulating film 130 by the battery casing 110.

[0095] The battery casing 110 can be made of steel or aluminum. Those skilled in the art will understand that steel and aluminum casings have different hardness and therefore different requirements for insulation performance. Based on this, when the battery casing 110 is made of steel, then 15 ≤ (S2×F2) / (S1×F1) ≤ 50. While the overall strength of a steel-cased battery is high, the adhesion strength between the surface of the steel casing and the first insulating film 120 and the second insulating film 130 is relatively weak. This ensures a good repair rate, so a larger value for (S2×F2) / (S1×F1) can be chosen to improve the adhesion strength between the battery cell 1 and the base plate 200. Therefore, in this embodiment, a value within the range of 15 to 50 is selected to ensure the adhesion strength between the battery cell 1 and the base plate 200 while maintaining a good repair yield for the first insulating film 120 and the second insulating film 130 on the battery cell.

[0096] When the battery casing 110 is made of aluminum, then 0.83 ≤ (S2×F2) / (S1×F1) ≤ 25. The surface of the aluminum casing has good adhesion strength to the first insulating film 120 and the second insulating film 130. The value of (S2×F2) / (S1×F1) can be chosen to be smaller to improve the rework yield of the first insulating film 120 and the second insulating film 130 on the battery cell 1. Therefore, in this embodiment, selecting a value within the range of 0.83 to 25 can ensure a better rework yield of the first insulating film 120 and the second insulating film 130 on the battery cell 1 while satisfying the premise of having better adhesion strength between the battery cell 1 and the base plate 200.

[0097] Those skilled in the art will understand that the battery casing is provided with terminal post assemblies, the function of which can be referred to the preceding description. For ease of understanding, the surface on which the terminal post assemblies are provided is defined as the casing's electrical contact surface.

[0098] The battery housing's electrical contact surface and mounting surface can be two opposing surfaces of the battery housing. When the battery cell 1 is in the installation state, taking the mounting surface of the battery housing 110 as the bottom surface as an example, the electrical contact surface of the battery housing 110 is the top surface of the battery housing 110, meaning the terminal assembly is located at the top of the battery housing 110.

[0099] The casing's electrical contact surface and the casing's mounting surface can also be the same surface of the battery casing. When the battery cell 1 is in the installed state, taking the casing mounting surface as the bottom surface of the battery casing 110 as an example, the casing's electrical contact surface is also the bottom surface of the battery casing 110, meaning the terminal assembly is located at the bottom of the battery casing 110. It should be noted that when the casing's electrical contact surface and the casing mounting surface are the same surface of the battery casing, the second insulating film 130 and the first insulating film 120 must avoid the terminal assembly, i.e., the conductivity of the terminal assembly must be maintained.

[0100] The casing electrical contact surface and the casing mounting surface can also be the two surfaces connected to the battery casing. When the battery cell 1 is in the installation state, taking the casing mounting surface as the bottom surface of the battery casing 110 as an example, the casing electrical contact surface is also the side surface of the battery casing 110, that is, the terminal assembly is located on the side between the top and bottom of the battery casing 110.

[0101] During use, various chemical reactions occur inside battery cell 1, generating a large amount of gas and causing the internal pressure of battery cell 1 to rise. Therefore, in order to prevent the battery cell 1 from exploding due to excessive internal pressure, an explosion-proof valve (not shown in the figure) is usually installed on the battery casing 110, that is, a weak structure is created on the battery casing 110.

[0102] When battery cell 1 is operating normally, the internal pressure is within the normal range, and the explosion-proof valve remains intact and sealed to prevent leakage of electrolyte, gas, etc. inside battery cell 1. When the internal pressure of battery cell 1 rises sharply due to abnormal conditions such as overcharging, overheating, or short circuit, reaching or exceeding the opening pressure set by the explosion-proof valve, the explosion-proof valve will rupture or be pushed open, allowing the high-pressure gas and heat inside the battery casing 110 to be released, thereby reducing the internal pressure of the battery casing 110 and preventing serious safety accidents such as explosion of battery cell 1.

[0103] For ease of understanding, the surface of the battery housing 110 where the explosion-proof valve is located is defined as the housing pressure relief surface. The housing pressure relief surface and the housing mounting surface can be two opposing surfaces of the battery housing. When the battery cell 1 is in the installed state, taking the housing mounting surface as the bottom surface of the battery housing 110 as an example, the housing pressure relief surface is the top surface of the battery housing 110, meaning the explosion-proof valve is located at the top of the battery housing 110. During thermal runaway pressure relief of the battery cell 1, high-temperature, high-pressure substances are ejected upwards through the ruptured explosion-proof valve.

[0104] The pressure relief surface and the mounting surface of the battery casing can also be the same surface of the battery casing. When battery cell 1 is in the installed state, taking the mounting surface of the battery casing 110 as the bottom surface as an example, the pressure relief surface of the battery casing 110 is also the bottom surface of the battery casing 110, that is, the explosion-proof valve is located at the bottom of the battery casing 110. When battery cell 1 experiences thermal runaway pressure relief, high-temperature and high-pressure substances are ejected downwards through the ruptured explosion-proof valve.

[0105] The pressure relief surface and the mounting surface of the housing can also be the two surfaces connected to the battery housing. When the battery cell 1 is in the installed state, taking the bottom surface of the battery housing 110 as an example, the pressure relief surface is also the side surface of the battery housing 110, that is, the explosion-proof valve is located on the side between the top and bottom of the battery housing 110. When the battery cell 1 experiences thermal runaway pressure relief, high-temperature and high-pressure substances are ejected to the side through the ruptured explosion-proof valve.

[0106] like Figure 1 As shown in the illustration, this application also discloses a battery pack, which includes a base plate 200 and battery units 1 disposed on the base plate 200. The base plate 200 supports the battery units 1. For example, the battery pack may include a battery housing 2, and the base plate 200 of the battery housing 2 is the base plate of the battery pack. It should be noted that the battery pack may also omit the battery housing 2, and the battery units 1 may be directly arranged in the corresponding space of the vehicle chassis; in this case, the base plate 200 of the battery pack becomes part of the vehicle.

[0107] The battery unit 1 in this embodiment is the battery unit 1 disclosed in the above embodiment. The battery pack disclosed in this application embodiment has the above-mentioned battery unit 1, and therefore has all the technical effects of the above-mentioned battery unit 1, which will not be repeated here.

[0108] Furthermore, the battery unit 1 can be adhesively bonded to the base plate 200, and the adhesive layer 140 between the housing mounting surface and the base plate 200 covers the first insulating film 120 and the second insulating film 130 on the housing mounting surface. The adhesive layer 140 can completely cover the first insulating film 120 and the second insulating film 130 on the housing mounting surface, which can improve the insulation performance of the battery pack and the bonding strength between the battery unit 1 and the base plate 200.

[0109] Given the fluidity of the adhesive layer 140 during bonding, the adhesive layer 140 can extend from the housing mounting surface to each housing side surface of the battery housing 110, which is the surface connected to the housing mounting surface, thereby further improving the bonding and fixing effect and the insulation protection effect of the battery cell 1.

[0110] The base plate 200 can be a support plate that only provides support, or it can be a heat exchange plate that exchanges heat with the battery unit 1. The heat exchange plate can be a metal plate, which utilizes the high thermal conductivity of the metal plate to assist in the heat dissipation of the battery unit 1. The heat exchange plate can also be a medium plate through which a heat exchange medium flows, which uses the circulating heat exchange medium to help control the temperature of the battery unit 1 so as to keep the temperature of the battery unit 1 within a reasonable range.

[0111] This application also discloses an insulation treatment method for a battery cell, wherein the battery cell 1 is used to be mounted on a base plate 200, and the battery cell 1 includes a battery casing 110. The insulation treatment method disclosed in this embodiment includes a first insulating film pasting step and a second insulating film pasting step.

[0112] The first step is the pasting of the insulating film;

[0113] A first insulating film 120 is attached to the side surface of the battery housing 110, and at least a portion of the edge of the first insulating film 120 is extended to the housing mounting surface, which is the side surface of the battery housing 110 facing the base plate 200, and the side surface of the battery housing 110 is the surface of the battery housing 110 that is connected to the housing mounting surface.

[0114] Second step: Applying the insulating film;

[0115] If the second insulating film 130 is pasted on the mounting surface of the housing, then 0.83≤(S2×F2) / (S1×F1)≤54, and F2>F1;

[0116] Wherein, S1 is the area of ​​the first insulating film 120 on the mounting surface of the housing, in mm. 2 ;

[0117] S2 is the area of ​​the second insulating film 130 on the mounting surface of the housing, in mm. 2 ;

[0118] F1 is the peel strength of the first insulating film 120, in N / mm;

[0119] F2 is the peel strength of the second insulating film 130, in N / mm.

[0120] It should be noted that the specific parameters and structures of the second insulating film 130 and the first insulating film 120, as well as their positional relationship with the battery casing 110, can be referred to the battery cell 1 disclosed in the above embodiments, and will not be repeated here.

[0121] To verify the technical effectiveness of the battery cell disclosed in the embodiments of this application, vibration tests and repair performance tests were conducted on the battery cell. The specific test process is as follows:

[0122] A batch of sample batteries were selected. During the assembly process, the sample batteries were assembled using the same production line, the same manufacturing process, and the same structural dimensions. The four sides of the assembled sample batteries were covered with a first insulating film 120. The first insulating film 120 on the four sides (i.e., the side surfaces of the casing) extended towards the bottom surface (i.e., the mounting surface of the casing) and covered part of the bottom surface. The exposed part of the mounting surface of the casing was covered with a second insulating film 130. The first insulating film 120 and the second insulating film 130 covered by each group of sample batteries were the same in terms of material, thickness, and other performance parameters, except for the peel strength and the coverage area. For details, please refer to the table in the example.

[0123] Peel strength performance test:

[0124] The insulating film samples to be tested (samples of the first insulating film 120 and the second insulating film 130) were cut to a size of 25mm*150mm and respectively attached to the first test substrate (simulating the mounting surface of the housing). They were rolled twice with rollers and left to stand at room temperature for 6 hours. The fixed end of the universal testing machine was used to clamp the test substrate horizontally, and the loading end was used to hold the free end of the insulating film sample. The sample was peeled at a speed of 300mm / min at a 90° vertical angle (i.e., the direction of the peeling force was perpendicular to the first test substrate). The peeling was continued for a length of 100mm. The force value curve of the peeling force was recorded. The effective line segment was selected, and the peel strength (N / mm) was calculated as: average peel force (N) ÷ film width of the insulating film sample (mm).

[0125] 1. Vibration test:

[0126] The sample battery and the second test substrate (simulation substrate 200) were bonded together with polyurethane structural adhesive with a thickness of 1.5 mm. The sample battery and the second test substrate were placed in a 45°C environment and left to stand for 48 hours. The test instrument used a three-dimensional vibration platform. The sample battery and the second test substrate were placed on the vibration platform and clamped. Vibration was performed in the X, Y and Z directions respectively. The vibration frequency was 200 Hz, the vibration time was 21 hours, and the temperature was 60°C.

[0127] After vibration, check whether there is any cracking or separation between the bottom of the sample battery and the second test substrate. The specific inspection method is as follows: spray red ink around the bottom of the sample battery. After the red ink dries, remove the sample battery and the second test substrate and observe whether there is any red mark between the bottom of the sample battery and the second test substrate. If there is, it proves that the connection has failed.

[0128] 2. Performance testing upon return for repair:

[0129] 100 sample batteries were selected for each embodiment. The performance and dimensional parameters of the first and second insulating films were the same. The sample batteries were clamped at the fixed end of the universal testing machine after being coated. One end of the first / second insulating film was torn off and clamped at the loading end of the machine. A force of 3.5 N / mm was applied and the film was peeled off vertically at 300 mm / min at 90°. After the peeling was completed, the first / second insulating film was observed to see if it was deformed or damaged. The average value was recorded. If the pass rate was greater than 96% (i.e., 0.96), it was considered qualified. This shows that the rework pass rate of the first / second insulating film was low.

[0130] Table 1 Comparison of Battery Cell Vibration Test and Repair Performance Test

[0131]

[0132]

[0133] As shown in Table 1, when (S2×F2) / (S1×F1) is less than 15 but not less than 0.83, the rework performance test results (rework yield) are all not less than 0.98 (i.e., 98%), for example, in Examples 1, 2, 3, 4, 5, 7, 10, 11, 12, 13, 14, 15, 16, 17, and 18. When (S2×F2) / (S1×F1) is less than 2 but not less than 0.83, the rework performance test results (rework yield) are all 1 (i.e., 100%), for example, in Examples 2, 3, 12, 17, and 18.

[0134] In Examples 1-22, there was no cracking or separation at the bonding joint between the sample battery and the second test substrate. Moreover, the rework performance test results were all greater than 96%, which can ensure the bonding strength between the battery cell and the base plate and prevent the problem of low bonding yield due to rework difficulties.

[0135] The results shown in Comparative Examples 1-3 indicate that when (S2×F2) / (S1×F1) is less than 0.83, although the rework performance test results (rework yield) are all 1, which meets the rework yield requirements, cracking and separation occur at the bonding points.

[0136] The results shown in Comparative Examples 4-6 indicate that when (S2×F2) / (S1×F1) is higher than 54, although there is no cracking or separation at the bonding point, the rework performance test results (rework yield) are all below 96%, which does not meet the rework yield requirements.

[0137] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0138] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0139] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0140] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A battery cell for mounting on a base plate (200), characterized in that, The battery housing (110) is partially covered with a first insulating film (120), and a second insulating film (130) is provided on the housing mounting surface of the battery housing (110). The housing mounting surface is the side surface of the battery housing (110) facing the base plate (200). Then, 0.83≤(S2×F2) / (S1×F1)≤54, F1 is 0.2N / mm~0.9N / mm, F2 is 0.5 N / mm~3N / mm, and F2>F1. The value range of S2 / S1 is 0.5~3.

8. Wherein, S1 is the area of ​​the first insulating film (120) on the housing mounting surface, in mm. 2 ; S2 is the area of ​​the second insulating film (130) on the housing mounting surface, in mm. 2 ; F1 is the peel strength of the first insulating film (120), in N / mm; F2 is the peel strength of the second insulating film (130), in N / mm.

2. The battery cell as described in claim 1, characterized in that, The area S1 of the first insulating film (120) on the housing mounting surface is 770 mm. 2 ~24225mm 2 ; The area S2 of the second insulating film (130) on the housing mounting surface is 380 mm. 2 ~96900 mm 2 .

3. The battery cell as described in claim 1, characterized in that, On the housing mounting surface, at least one edge of the second insulating film (130) is spaced from the edge of the corresponding side of the housing mounting surface.

4. The battery cell as described in claim 3, characterized in that, On the housing mounting surface, the edge of either side of the second insulating film (130) is spaced from the edge of the corresponding side of the housing mounting surface.

5. The battery cell as described in claim 1, characterized in that, On the housing mounting surface, at least one edge of the second insulating film (130) is flush with the edge of the corresponding side of the housing mounting surface.

6. The battery cell as described in claim 5, characterized in that, On the housing mounting surface, the second insulating film (130) covers the entire area of ​​the housing mounting surface.

7. The battery cell as claimed in claim 1, characterized in that, The housing mounting surface has a rectangular structure, and at least two relatively long sides are covered with the first insulating film (120).

8. The battery cell as claimed in claim 7, characterized in that, The first insulating film (120) is covered on all four sides of the housing mounting surface.

9. The battery cell as claimed in claim 1, characterized in that, On the housing mounting surface, the first insulating film (120) is flush with at least one edge of the second insulating film (130).

10. The battery cell as claimed in claim 9, characterized in that, On the mounting surface of the housing, the edges of either side of the first insulating film (120) and the second insulating film (130) are flush and joined.

11. The battery cell as claimed in claim 1, characterized in that, On the mounting surface of the housing, there is an overlapping area between the first insulating film (120) and the second insulating film (130).

12. The battery cell as claimed in claim 11, characterized in that, In the overlapping area, the first insulating film (120) is located on the side of the second insulating film (130) that is opposite to the housing mounting surface; or, In the overlapping area, the second insulating film (130) is located on the side of the first insulating film (120) that is opposite to the housing mounting surface.

13. The battery cell according to any one of claims 1-12, characterized in that, The thickness of the first insulating film (120) is 80 μm ~ 250 μm; And / or, The thickness of the second insulating film (130) is 80 μm ~ 250 μm.

14. The battery cell according to any one of claims 1-12, characterized in that, The first insulating film (120) is made of polyethylene terephthalate, polyimide, polypropylene or acrylic adhesive; And / or, The second insulating film (130) is made of polyethylene terephthalate, polyimide, polypropylene or acrylic adhesive.

15. The battery cell according to any one of claims 1-12, characterized in that, The insulating region formed by the first insulating film (120) and the second insulating film (130) covers the entire area of ​​the housing mounting surface.

16. The battery cell according to any one of claims 1-12, characterized in that, The hardness of the battery casing (110) is HB20~HB110.

17. The battery cell according to any one of claims 1-12, characterized in that, If the battery casing (110) is made of steel, then 15 ≤ (S2×F2) / (S1×F1) ≤ 50.

18. The battery cell according to any one of claims 1-12, characterized in that, If the battery casing (110) is made of aluminum, then 0.83 ≤ (S2×F2) / (S1×F1) ≤ 25.

19. The battery cell according to any one of claims 1-12, characterized in that, The battery casing is provided with a terminal post assembly, and the surface of the battery casing on which the terminal post assembly is provided is the casing contact surface; The electrical contact surface of the housing and the mounting surface of the housing are two surfaces of the battery housing that are arranged opposite to each other. or, The electrical contact surface of the housing and the mounting surface of the housing are two surfaces connected to the battery housing; or, The electrical contact surface of the housing and the mounting surface of the housing are the same surface of the battery housing.

20. The battery cell according to any one of claims 1-12, characterized in that, An explosion-proof valve is provided on the battery casing, and the surface of the battery casing on which the explosion-proof valve is provided is the casing pressure relief surface; The pressure relief surface of the housing and the mounting surface of the housing are two surfaces of the battery housing that are arranged opposite to each other. or, The pressure relief surface of the housing and the mounting surface of the housing are two surfaces connected to the battery housing; or, The pressure relief surface of the housing and the mounting surface of the housing are the same surface of the battery housing.

21. A battery pack, characterized in that, It includes a base plate (200) and a battery cell disposed on the base plate (200), wherein the battery cell is the battery cell as described in any one of claims 1-20.

22. The battery pack as claimed in claim 21, characterized in that, The battery cell is glued to the base plate (200), and the adhesive layer (140) between the housing mounting surface and the base plate (200) covers the first insulating film (120) and the second insulating film (130) on the housing mounting surface.

23. The battery pack as claimed in claim 22, characterized in that, The adhesive layer (140) extends from the housing mounting surface to each housing side surface of the battery housing (110), the housing side surface being the surface connected to the housing mounting surface.

24. The battery pack as claimed in claim 21, characterized in that, The base plate (200) is a heat exchange plate.

25. A method for insulating a battery cell, characterized in that, The battery unit is used to be mounted on the base plate (200) and includes a battery housing (110). The insulation treatment method includes a first insulation film pasting step and a second insulation film pasting step. The first insulating film pasting step includes: pasting a first insulating film (120) onto the housing side surface of the battery housing (110), and extending at least a portion of the edge of the first insulating film (120) to the housing mounting surface, wherein the housing mounting surface is the side surface of the battery housing (110) facing the base plate (200), and the housing side surface is the surface of the battery housing (110) connected to the housing mounting surface; The second insulating film pasting step includes: pasting the second insulating film (130) onto the mounting surface of the housing, then 0.83≤(S2×F2) / (S1×F1)≤54, F1 is 0.2N / mm~0.9N / mm, F2 is 0.5 N / mm~3N / mm, and F2>F1, and the value range of S2 / S1 is: 0.5~3.8; Wherein, S1 is the area of ​​the first insulating film (120) on the housing mounting surface, in mm. 2 ; S2 is the area of ​​the second insulating film (130) on the housing mounting surface, in mm. 2 ; F1 is the peel strength of the first insulating film (120), in N / mm; F2 is the peel strength of the second insulating film (130), in N / mm.

Images