A battery pack

Abstract

This invention provides a battery pack with good insulation strength, which helps to improve the safety performance of the battery pack. The battery pack includes a housing, a battery array, and structural adhesive; the battery array is housed in the housing, and the battery array includes multiple battery cells arranged in parallel, each battery cell including multiple batteries, the multiple batteries including a first battery and a second battery, the first battery and the second battery are arranged alternately, and adjacent first batteries and second batteries are connected by a first buffer pad; the first battery and the second battery respectively include a shell and a first insulating film covering the outer surface of the shell; the structural adhesive is used to fix the first battery and the second battery to the housing; and, among the second batteries in the battery array, the second battery with the most adjacent second batteries m satisfies the following relationship (1):

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery pack. Background Technology

[0002] Currently, many power battery packs integrate the batteries directly into the housing to improve assembly efficiency and reduce costs, which is the CTP (Cell to Pack) structure. This simplifies the original battery module design, thereby reducing the number of parts, improving integration efficiency and energy density, and reducing costs.

[0003] In a CTP (Computer-to-Pack) structure, the battery is typically fixed to the casing using adhesive. The battery casing is usually made of metal (such as aluminum). Because batteries have high insulation requirements, insulating films are typically applied to the sides and bottom of the battery. However, the adhesion strength between the insulating film and the structural adhesive is relatively weak, and the battery pack is prone to adhesion failure during long-term use. Therefore, to improve the adhesion strength between the battery and the battery casing, the insulating film on the bottom of the battery is usually removed, allowing the battery to be fixed to the casing through its metal bottom surface, thus improving the adhesion strength. On the one hand, the battery casing is generally also made of metal, so the two exposed metal surfaces are prone to insulation problems. On the other hand, the bottom of the battery usually has rounded corners. During production, considering tolerances, the insulating film on the side of the battery usually exposes these rounded corners to prevent gaps or wrinkles at the corners. This design can easily lead to insufficient insulation between the exposed rounded corners of adjacent batteries in the battery pack, resulting in safety issues. Summary of the Invention

[0004] To address at least one deficiency in the existing technology, the present invention provides a battery pack with good insulation strength, thereby improving the safety performance of the battery pack.

[0005] To achieve its objective, the present invention provides the following technical solution:

[0006] This invention provides a battery pack, including a housing, a battery array, and structural adhesive:

[0007] The battery array is housed in the housing, and the battery array includes multiple battery cells arranged in parallel. Each battery cell includes multiple batteries, and the multiple batteries include a first battery and a second battery. The first battery and the second battery are arranged alternately. Between two adjacent rows of battery cells, the first battery and the second battery are arranged alternately.

[0008] The first battery and the second battery each include a housing and a first insulating film covering the outer surface of the housing. The first insulating film covering the housing of the second battery has a hollow area on the side corresponding to the bottom and lower part of the second battery. The rounded corner of the edge of the lower side of the second battery is located in the hollow area, so that the area of ​​the housing of the second battery corresponding to the hollow area is exposed to the first insulating film.

[0009] The structural adhesive is applied between the bottom surface of the first battery, the bottom surface of the second battery, and the housing, and covers the hollow area of ​​the second battery, for fixing the first battery and the second battery to the housing;

[0010] Furthermore, among the second cells in the battery array, the second cell with the most adjacent second cells m satisfies the following relationship (1):

[0011]

[0012] Among them, R bc R is an approximate calculated value of the insulation resistance between the second battery and the casing. bb2 This is an approximate calculated value of the insulation resistance between two adjacent second batteries.

[0013] Furthermore, the adjacent first battery and second battery are connected by a first buffer pad;

[0014] The battery cells in two adjacent columns are connected by a second buffer pad;

[0015] The casing may or may not have an insulating coating on the bottom surface of the first battery and the surface corresponding to the bottom surface of the second battery.

[0016] A first limiting strip may or may not be provided between the bottom surface of each battery and the housing.

[0017] Furthermore, in relation (1), the R... bb2 Calculate according to the following relation (2):

[0018]

[0019] In the relationship (2), ρ2 is the volume resistivity of the structural adhesive, r2 is the radius of the rounded corner of the side of the battery, L1 is the thickness of the first insulating film, W1 is the thickness of the first buffer pad, W2 is the thickness of the second buffer pad, and H3 is the height of the hollow area.

[0020] Furthermore, when the insulating coating is not provided, R in equation (1) bcCalculate according to the following relationship (3):

[0021]

[0022] When the insulating coating is provided, R in equation (1) bc Calculate according to the following relation (4):

[0023]

[0024] In the above equations (3) and (4), ρ1 is the volume resistivity of the first limiting strip, ρ2 is the volume resistivity of the structural adhesive, H1 is the thickness of the structural adhesive between the bottom surface of a single battery and the housing, S is the bottom surface area of ​​a single battery, n1 is the number of first limiting strips corresponding to the bottom surface of a single battery, S1 is the contact area between a single first limiting strip and the bottom surface of a single battery, ρ3 is the volume resistivity of the insulating coating, and L2 is the thickness of the insulating coating.

[0025] Preferably, the first buffer pad connects the first battery and the second battery in the battery cell into one unit by means of adhesive bonding;

[0026] And / or, the second buffer pad connects two adjacent rows of battery cells into one unit by means of adhesive bonding;

[0027] And / or, a support structure is provided on the outside of the battery cell to keep the first buffer pad in a compressed state.

[0028] Furthermore, the rounded corner area at the bottom of the second battery is located within the hollowed-out area.

[0029] Preferably, the second battery of each battery cell includes a side facing the battery cells in the adjacent row, and the lower edge rounded corner of the casing of the second battery corresponding to the hollow area of ​​the side is covered by a second insulating film.

[0030] Preferably, between two adjacent rows of battery cells, each battery includes a side facing the adjacent row of battery cells, the lower edge of which is rounded and covered by a second insulating film.

[0031] In the outer battery cell, the lower edge rounded corner of the side opposite to the side of the battery with the second insulating film is also covered by the second insulating film.

[0032] Preferably, inside the housing, a second limiting strip is provided on the outside of the battery cell located on the outer side to limit the overflow height of the structural adhesive, and to allow the structural adhesive to cover the hollow area.

[0033] In some implementations, ρ1 ≥ 1 × 10 13 Ω·cm, where ρ2≥7.5×10 9 Ω·cm, where ρ3≥1×10 13 Ω·cm;

[0034] And / or, the material of the structural adhesive is selected from one or more of polyurethane and epoxy resin;

[0035] And / or, the thickness W1 of the first buffer pad is 0.5-1.5 mm;

[0036] And / or, the thickness W2 of the second buffer pad is 0.5-5mm;

[0037] And / or, the thickness L1 of the first insulating film is 0.015-0.2 mm;

[0038] And / or, the thickness H1 of the structural adhesive between the bottom surface of a single battery and the housing is 0.5-2.5 mm;

[0039] And / or, the thickness L2 of the insulating coating is 0.1-0.3 mm;

[0040] And / or, the height H2 of the second limiting bar satisfies: H1+r1≤H2≤H1+r1+3mm, where r1 is the radius of the rounded corner at the bottom of the battery;

[0041] And / or, the height H3 of the hollowed-out area satisfies: r1 < H3 ≤ H2, where r1 is the radius of the bottom corner of the battery;

[0042] And / or, 0 < r2 ≤ 3.5 mm.

[0043] The technical solution provided by this invention has the following beneficial effects:

[0044] In the battery pack of the present invention, a first battery without a hollow area and a second battery with a hollow area are mixed and assembled, and the requirements of relation (1) are met by reasonably setting the relevant parameters. This can improve the safety performance of the battery pack, increase the insulation strength of the battery pack, and also have good structural strength. At the same time, it greatly reduces the design cost and is conducive to improving development efficiency. Attached Figure Description

[0045] Figure 1 This is a front view schematic diagram of the first battery in one embodiment;

[0046] Figure 2 This is a front view schematic diagram of the second battery in one embodiment;

[0047] Figure 3This is a top view of the battery before the first insulating film is applied.

[0048] Figure 4 This is a schematic diagram of a battery pack in one embodiment;

[0049] Figure 5 A side view of two rows of battery cells arranged side by side;

[0050] Figure 6 In order to be in Figure 5 A schematic diagram showing the addition of a second insulating film to the existing structure;

[0051] Figure 7 for Figure 5 A schematic diagram of the bottom of the battery array;

[0052] Figure 8 This is a bottom view of a battery array with three rows of battery cells arranged side by side.

[0053] Figure 9 Calculate the equivalent shape for the insulation resistance between two adjacent second cells;

[0054] Figure 10 for Figure 9 Simplified shape;

[0055] Figure 11 for Figure 9 Enlarged view of point A in the middle;

[0056] Figure 12 for Figure 10 Enlarged diagram of point B in the middle.

[0057] Reference numerals: Battery unit 100, first battery 1, second batteries 2, 2a, 2b, housing 3, first insulating film 4, lower side 5, bottom surface 6, side 7, box body 8, first buffer pad 9, end plate 10, beam 11, structural adhesive 12, first limiting strip 13, second limiting strip 14, hollow area 15, second buffer pad 16, insulating coating 17, second insulating film 18, battery array 19. Detailed Implementation

[0058] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0060] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the construction shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. The terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0061] See Figure 1-8 The battery pack provided by the present invention includes a housing 8, a battery array 19, and structural adhesive 12.

[0062] The battery array 19 is housed within the casing 8. See also... Figure 5 , Figure 7 , Figure 8 The battery array comprises multiple battery cells 100 arranged in parallel. See also Figure 4 Each battery unit 100 includes multiple batteries, including a first battery 1 and a second battery 2. In each battery unit 100, the first battery 1 and the second battery 2 are arranged alternately to form a row of batteries; and a first buffer pad 9 is provided between adjacent batteries to connect adjacent first batteries 1 and second batteries 2 into a single unit. See also... Figure 7 , Figure 8 Between two adjacent rows of battery cells 100, the first battery 1 and the second battery 2 are also arranged alternately. Specifically, the multiple parallel battery cells 100 include multiple rows and columns of batteries, and the first battery 1 and the second battery 2 are arranged alternately between each row, each column, and between adjacent rows and columns. A second buffer pad 16 is provided between two adjacent rows of battery cells 100, which connects the two adjacent rows of battery cells 100 into one unit.

[0063] The first battery 1 includes a housing 3 and a first insulating film 4 covering the outer surface of the housing 3. Similarly, the second battery 2 also includes a housing 3 and a first insulating film 4 covering the outer surface of the housing 3. The difference between the second battery 2 and the first battery 1 is that the first insulating film 4 of the second battery 2 has a hollow area 15. Specifically, the first insulating film 4 has hollow areas 15 corresponding to the bottom surface 6 and the lower side surface 5 of the second battery 2. Thus, the housing 3 of the second battery 2 corresponding to the position of the hollow area 15 is exposed to the first insulating film 4. The surface of the housing 3 of the second battery 2 in these areas is not covered by the first insulating film 4. Specifically, the rounded corner of the lower side surface 5 of the second battery 2 is located within the hollow area 15, that is, the rounded corner of the lower side surface 5 of the second battery 2 is not covered by the first insulating film 4. Specifically, the lower side surface 5 is the side part adjacent to the bottom of the housing of the second battery; specifically, the rounded corner area of ​​the bottom of the second battery 2 is located within the hollow area 15. The first insulating film 4 of the first battery 1 does not have such a perforated area 15, that is, the bottom surface 6 and side surface 7 of the first battery 1 are completely covered by the first insulating film 4. Structural adhesive 12 is provided between the bottom surface of the first battery 1, the bottom surface of the second battery 2, and the housing 8. Specifically, structural adhesive 12 is provided between the bottom surface 6 of the first battery 1 and the housing 8, and between the bottom surface 6 of the second battery 2 and the housing 8. The structural adhesive 12 covers the perforated area 15 of the first insulating film 4 of the second battery 2, so that the exposed bottom surface 6 of the housing 3 and the lower side surface 5 of the housing 3 of the second battery 2 are covered by the structural adhesive 12; the structural adhesive 12 fixes the first battery 1 and the second battery 2 to the housing 8. A first limiting strip 13 may be provided between the bottom surface 6 of each battery and the housing 8, or the first limiting strip 13 may not be provided; for example... Figure 4 In the example shown, a first limiting strip 13 is provided between the bottom surface 6 of each battery and the housing 8.

[0064] An insulating coating 17 may be provided on the surfaces of the housing 8 corresponding to the bottom surface 6 of the first battery 1, and on the surfaces of the housing 8 corresponding to the bottom surface 6 of the second battery 2, or an insulating coating 17 may not be provided. Figure 4 In the example shown, an insulating coating 17 is provided on the surface of the housing 8 corresponding to the bottom surface 6 of the first battery 1 and on the surface of the housing 8 corresponding to the bottom surface 6 of the second battery 2.

[0065] In this invention, among the second batteries included in the battery array of the battery pack, the second battery with the most adjacent second batteries m satisfies the following relationship (1):

[0066]

[0067] Among them, R bc R is the calculated value of the insulation resistance between the second battery and the casing. bb2This is an approximate calculated value of the insulation resistance between two adjacent second batteries.

[0068] Specifically, with Figure 7 For example, the battery array includes multiple second batteries 2. Some second batteries are adjacent to one second battery from an adjacent column, while some second batteries, such as second battery 2a, are adjacent to two second batteries from adjacent columns. Second battery 2a is... Figure 7 The battery array shown has the most adjacent second cells, with a number of 2 for each second cell. Figure 7 In the example, the second battery 2a must satisfy the above relationship (1), where m = 2, that is, m is the number of adjacent second batteries to the second battery 2a. Similarly, with Figure 8 For example, in this battery array, the second battery with the most adjacent second batteries is the second battery 2b. The second battery 2b is adjacent to the second batteries of 4 battery cells from adjacent columns. The second battery 2b must satisfy the above relationship (1), where m = 4.

[0069] Among them, R in relation (1) bb2 Calculate according to the following relation (2):

[0070]

[0071] When the insulating coating 17 is not provided, the R in equation (1) bc Calculate according to the following relationship (3):

[0072]

[0073] When the insulating coating 17 is provided, the R in equation (1) bc Calculate according to the following relation (4):

[0074]

[0075] In the above formula, the volume resistivity of the first limiting strip 13 is ρ1, in Ω·cm; the volume resistivity of the structural adhesive 12 is ρ2, in Ω·cm; the thickness of the structural adhesive 12 between the bottom surface 6 of a single battery and the housing 8 is H1, in cm; and the area of ​​the bottom surface 6 of a single battery is S, in cm². 2 The number of first limiting strips 13 corresponding to the bottom surface 6 of a single battery is n1; the contact area between a single first limiting strip 13 and the bottom surface 6 of a single battery is S1, in cm. 2The volume resistivity of the insulating coating 17 is ρ3, in Ω·cm; the thickness of the insulating coating 17 is L2, in cm; the radius of the rounded corner of the side surface 5 of the battery is r2, that is, the radius of the rounded corner at the edge between two adjacent side surfaces of the battery (e.g., Figure 7 (As shown), the unit is cm; the thickness of the first insulating film 4 is L1, in cm; the thickness of the first buffer pad 9 is W1, in cm; the thickness of the second buffer pad 16 is W2, in cm; the height of the hollow area 15 is H3, in cm.

[0076] In the text, the rounded corners of the battery's sides refer to the rounded corners at the edges between two adjacent sides of the battery, where r2 is the radius of the rounded corner. See [link to relevant documentation]. Figure 3 The illustration shows that this rounded corner will be referred to as rounded corner r2 below. In this text, the rounded corner at the bottom of the battery refers to the rounded corner where the bottom surface and the side surface of the battery intersect, and r1 is the radius of this rounded corner. See [link to relevant documentation]. Figure 2 The illustration.

[0077] In the battery pack of the present invention, a first battery 1 without a cutout area 15 and a second battery 2 with a cutout area 15 are mixed and assembled. Preferably, the first battery 1 and the second battery 2 in the battery unit 100 are connected into one unit by a first buffer pad 9; preferably, adjacent rows of battery units 100 are connected into one unit by a second buffer pad 16. This battery pack structure has good structural strength. In the present invention, the battery pack satisfies the above-mentioned relational calculation. The requirements dictate that the battery pack must have superior insulation strength to prevent insulation failure and effectively ensure its safety performance.

[0078] In the above relation (1), let That is, R ≥ 10MΩ. The larger the calculated value of R, the greater the insulation strength of the battery pack. In order to meet the requirements of good insulation strength, the values ​​of various relevant parameters can be reasonably set through the relationships (1)-(4) to obtain the required calculated value of R, thereby improving the insulation safety of the battery. The implementation method of this invention is simple, requires few parts, and has low cost. It can greatly improve the integration efficiency and design efficiency of the battery pack and reduce costs.

[0079] To facilitate understanding, the following will be explained... Figure 9-12 The approximate calculated value R of the insulation resistance between two adjacent second batteries in this invention. bb2 The calculation method is explained below:

[0080] Figure 9 This is a schematic diagram showing the bottom surface distribution of four adjacent batteries between two rows of adjacent battery cells 101 and 102; the equivalent insulation resistance of the structural adhesive between the hollowed-out areas of two adjacent second batteries 2 between the two rows of battery cells can be equivalent to... Figure 9The shape of the gray area circled in the middle is calculated, and its insulation resistance value is recorded as R. bb1 See also Figure 11 The method for extracting the shape of the gray area is as follows: O1 and O2 are the center points corresponding to the rounded corners r2 of two adjacent first batteries 1 in the two rows of battery units 101 and 102, respectively; connect O1 and O2 to draw an auxiliary line segment O1O2, and draw a tangent a1b1 through the rounded corner r2 (including the first insulating film) of the first battery 1 in battery unit 102, perpendicular to O1O2. Point a1 is the intersection of a1b1 and the side of the second battery 2 in battery unit 101, and point b1 is the intersection of a1b1 and the side of the second battery 2 in battery unit 102; through the rounded corner r2 of the first battery 1 in battery unit 101... 2 (including the first insulating film) is tangent to c1d1 and perpendicular to O1O2. Point c1 is the intersection (intersection line) of c1d1 and the side of the second battery 2 of battery unit 102, and point d1 is the intersection of c1d1 and the side of the second battery 2 of battery unit 101. a1 and d1 form a curve with the tangent of the side of the second battery 2 of battery unit 101, and b1 and c1 form a curve with the tangent of the side of the second battery 2 of battery unit 102. Finally, the equivalent cross-sectional shape a1b1c1d1 of the insulation resistance value of two adjacent second batteries 2 between the two rows of battery units 101 and 102 is obtained. Due to its relatively complex shape, the inventors have simplified its shape to Figure 10 The shape of the gray area circled in the middle, and the simplified shape corresponding to the insulation resistance value, are denoted as R. bb2 For a simplified version, please refer to [link / reference]. Figure 12 Its shape characteristics are as follows: O1 and O2 are the center points corresponding to the rounded corners r2 of two adjacent first batteries 1 in the two rows of battery units 101 and 102, respectively; connect O1 and O2 to form an auxiliary line segment O1O2; line segment a2d2 is parallel to O1O2 and tangent to the rounded corner of the side of the second battery 2 in battery unit 101; line segment b2c2 is parallel to O1O2 and tangent to the rounded corner of the side of the second battery 2 in battery unit 102; line segment a2b2 is perpendicular to O1O2 and tangent to the rounded corner of the side of the first battery 1 in battery unit 102; line segment c2d2 is perpendicular to O1O2 and tangent to the rounded corner of the side of the first battery 1 in battery unit 101. Because R bb1 >R bb2 Therefore, it is only necessary to confirm R. bb2 Meeting insulation performance requirements ensures R bb1 It also meets the insulation performance requirements, thus simplifying the calculation. R bb2 The calculation formula is given in relation (2) above.

[0081] In some embodiments, the first buffer pad 9 connects the first battery 1 and the second battery 2 in the battery unit 100 into one unit by means of adhesion, such as by adhesive bonding. By alternately connecting the individual first batteries 1 and second batteries 2 in the battery unit 100 into one unit, the structural strength of the entire battery pack can be improved, and the safety of the battery pack can be enhanced.

[0082] In some embodiments, the second buffer pad 16 connects adjacent rows of battery cells 100 together by adhesive bonding, such as by using glue. Specifically, by bonding the second buffer pad 16 to the battery cells 100 on both sides, the battery cells 100 are integrated, which can improve the structural strength of the entire battery pack and enhance its safety. The second buffer pad 16 also serves as a heat insulation buffer, ensuring the gap between adjacent battery cells. Specifically, the height of the second buffer pad 16 from the bottom of the battery is not less than the height of the hollow area 15 of the first insulating film 4 of the second battery 2, thereby facilitating the structural adhesive 12 to cover the surface of the housing 3 corresponding to the hollow area 15.

[0083] Furthermore, in all battery cells 100, a support structure is provided on the outside of the battery cell 100 to keep the first buffer pad 9 in a compressed state. The support structure is, for example, an end plate 10 located on the outside of the outer side of the battery cell 100. The end plate 10 may also have a beam 11 or other structure providing support for the battery pack. After the battery pack is assembled, the support structure provides support and insulation, and keeps the first buffer pad 9 between the first battery 1 and the second battery 2 of the battery cell 100 in a compressed state, possessing a certain amount of compression and rebound force, so that the two adjacent batteries form a whole. The first buffer pad 9 also provides heat insulation and buffering, and ensures the gap between two adjacent batteries. By binding the first battery 1 and the second battery 2 within the battery cell 100 together with the first buffer pad 9 and the second buffer pad 16, the first battery 1 with relatively weak adhesion and the second battery 2 with relatively strong adhesion can be regarded as a whole, greatly improving the structural strength after the batteries are stacked. By assembling the first battery 1 and the second battery 2 alternately, and using the first buffer pad 9 and the second buffer pad 16 to connect the batteries in each row and column into one unit, a battery pack with better bonding strength can be obtained.

[0084] In some examples, such as Figure 6As shown, there are multiple battery cells 100. Each battery cell 100 has a second battery 2, which includes a side facing the adjacent row of battery cells 100. The lower edge of the casing 3 of the second battery 2, corresponding to the hollowed-out area 15 of this side, is covered by a second insulating film 18, further improving insulation strength. More preferably, between two adjacent rows of battery cells 100, each battery includes a side facing the adjacent row of battery cells 100, and the lower edge of this side is covered by a second insulating film 18, further improving insulation strength. In the outer battery cells, the lower edge of the side opposite to the side of the battery with the second insulating film 18 is also covered by the second insulating film 18.

[0085] In this invention, an insulating coating 17 may or may not be provided on the surfaces of the housing 8 corresponding to the bottom surface 6 of the first battery 1, and on the surfaces of the housing 8 corresponding to the bottom surface 6 of the second battery 2. When an insulating coating 17 is provided, it helps to further enhance the insulation effect.

[0086] In some embodiments, within the housing 8, a second limiting strip 14 is provided on the outer side of the outermost battery cell 100 to limit the overflow height of the structural adhesive 12, and to allow the structural adhesive 12 to cover the hollowed-out area 15 of the second battery 2. Specifically, the structural adhesive 12 covers the surface of the housing 3 corresponding to the hollowed-out area 15. The height of the second limiting strip 14 limits the maximum thickness of the structural adhesive 12 on the side of the outermost battery of the battery cell 100. The length of the second limiting strip 14 can be specifically set to match the row or column of batteries corresponding to the position.

[0087] In this invention, the specific materials of the first insulating film 4, the second insulating film 18, the insulating coating 17, and the structural adhesive 12 are not particularly limited, and can be any materials applicable in the art. For example, the material of the first insulating film 4 or the second insulating film 18 may be, but is not limited to, polyester resin (PET), polycarbonate (PC), etc.; the material of the insulating coating 17 may be, but is not limited to, epoxy powder; and the material of the structural adhesive 12 may be, but is not limited to, one or more of polyurethane and epoxy resin. The materials of the first limiting strip 13 and the second limiting strip 14 may both be materials known in the art, such as, but not limited to, polycarbonate (PC) or other rigid plastics, foam, etc. The material of the first buffer pad 9 may be, but is not limited to, polypropylene foam (MPP), aerogel, etc.; and the material of the second buffer pad 16 may be, but is not limited to, polypropylene foam (MPP), aerogel, epoxy board, etc. The material of the battery casing 3 may be, for example, aluminum or steel, and the material of the housing 8 may be, for example, aluminum or steel.

[0088] In some examples, ρ1 is, for example, ≥1×10 13 Ω·cm, wherein ρ2 is, for example, ≥7.5×10 9Ω·cm, where ρ3 is, for example, ≥1×10 13 Ω·cm; the thickness W1 of the first buffer pad 9 is, for example, 0.5-1.5mm; the thickness W2 of the second buffer pad 16 is, for example, 0.5-5mm; the thickness L1 of the first insulating film 4 is, for example, 0.015-0.2mm; the thickness H1 of the structural adhesive 12 between the bottom surface 6 of a single battery and the housing 8 is, for example, 0.5-2.5mm, and when the first limiting strip 13 is provided, H1 is also the height of the first limiting strip 13; the thickness L2 of the insulating coating 17 is, for example, 0.1-0.3mm; the height H2 of the second limiting strip 14 satisfies: H1+r1≤H2≤H1+r1+3mm, where r1 is the radius of the bottom corner of the battery; the height H3 of the hollow area 15 satisfies: r1<H3≤H2; the radius r2 of the edge corner of the side surface 5 of the battery is 0<r2≤3.5mm. The number of first limiting strips 13 between the bottom surface 6 of a single battery and the housing 8 is not particularly limited; for example, it can be 0 strips, 1 strip, or multiple strips, such as 2-4 strips, or 2, 3, 4 strips, etc. In some examples, the radius r1 of the corner fillet of the bottom surface 6 of the battery is 0 < r1 ≤ 3.5 mm.

[0089] Example:

[0090] In one embodiment of this application, structural adhesive A, structural adhesive B, and a first limiting strip are used respectively for battery pack design, and the insulation performance of the battery pack is verified. A schematic diagram of the battery pack is shown below. Figure 1-5 , Figure 7-8 Structural adhesive A is a two-component polyurethane structural adhesive with a volume resistivity ρ2 of 7.6 x 10⁻⁶. 9 Ω·cm; Structural adhesive B is a two-component polyurethane structural adhesive with a volume resistivity ρ2 of 2.5 x 10 Ω·cm; 13 Ω·cm; The height of the first limiting strip 13 is 1mm, and the volume resistivity ρ1 of the first limiting strip 13 is 1x10 Ω·cm; 16 Ω·cm. The battery casing 3 is made of aluminum, and the housing 8 is also made of aluminum. The parameters of the battery pack are shown in Table 1 below:

[0091] Table 1

[0092]

[0093]

[0094] (i) Without an insulating coating, by changing the type of structural adhesive 12, and by changing the contact area S1 between a single first limiting strip 13 and the bottom surface 6 of a single battery, and / or the number n1 of the first limiting strips 13 corresponding to the bottom surface 6 of a single battery, multiple sets of experiments were conducted under different n1S1 / S×100% conditions. The R values ​​corresponding to each set of experiments were calculated using the relationships (1), (2), and (3), among which the R values ​​have Figure 7 The specific test results for the battery pack of the battery array shown are shown in Table 2-1. Figure 8 The specific test results of the battery pack of the battery array shown are shown in Table 2-2. When calculating the R value using relation (1) in Table 2-1, m = 2, and the calculated R value is shown in Table 2-1; when calculating the R value using relation (1) in Table 2-2, m = 4, and the calculated R value is shown in Table 2-2.

[0095] Table 2-1 (No insulating coating, m=2)

[0096]

[0097] Table 2-2 (No insulating coating, m=4)

[0098]

[0099]

[0100] (II) Assume an insulating coating with a thickness L2 of 0.15 mm and a volume resistivity ρ3 of 1 x 10⁻⁶. 15 Ω·cm. By changing the type of structural adhesive 12, and changing the contact area S1 between a single first limiting strip 13 and the bottom surface 6 of a single battery and / or the number n1 of first limiting strips 13 corresponding to the bottom surface 6 of a single battery, multiple sets of experiments were carried out under different n1S1 / S×100% conditions. The R value corresponding to each set of experiments was calculated using the relationships (1), (2), and (4), among which the R value with Figure 7 The specific test results for the battery pack of the battery array shown are shown in Table 3-1. Figure 8 The specific test results of the battery pack of the battery array shown are shown in Table 3-2. When calculating the R value using relation (1) in Table 3-1, m = 2, and the calculated R value is shown in Table 3-1; when calculating the R value using relation (1) in Table 3-2, m = 4, and the calculated R value is shown in Table 3-2.

[0101] Table 3-1 (with insulating coating, m=2)

[0102]

[0103] Table 3-2 (with insulating coating, m=4)

[0104]

[0105] In Tables 2-1, 2-2, 3-1, and 3-2, insulation resistance tests were conducted on the battery packs designed for each experimental group. A battery pack with a measured resistance ≥10MΩ was considered OK, while a resistance below 10MΩ was considered NG. See the "Insulation Resistance Test Results" in the tables for details. The experimental results show that all experimental groups with a calculated R value ≥10MΩ based on the formula of this invention passed the insulation test.

[0106] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A battery pack, characterized in that, Including the housing, battery array, and structural adhesive: The battery array is housed in the housing, and the battery array includes multiple battery cells arranged in parallel. Each battery cell includes multiple batteries, and the multiple batteries include a first battery and a second battery. The first battery and the second battery are arranged alternately. Between two adjacent rows of battery cells, the first battery and the second battery are arranged alternately. The first battery and the second battery each include a housing and a first insulating film covering the outer surface of the housing. The first insulating film covering the housing of the second battery has a hollow area on the side corresponding to the bottom and lower part of the second battery. The rounded corner of the edge of the lower side of the second battery is located in the hollow area, so that the area of ​​the housing of the second battery corresponding to the hollow area is exposed to the first insulating film. The structural adhesive is applied between the bottom surface of the first battery, the bottom surface of the second battery, and the housing, and covers the hollow area of ​​the second battery, for fixing the first battery and the second battery to the housing; Furthermore, among the second cells in the battery array, the second cell with the most adjacent second cells m satisfies the following relationship (1): Among them, R bc R is the calculated value of the insulation resistance between the second battery and the housing. bb2 This is an approximate calculated value of the insulation resistance between two adjacent second batteries.

2. The battery pack according to claim 1, characterized in that, The adjacent first battery and second battery are connected by a first buffer pad; The battery cells in two adjacent columns are connected by a second buffer pad; The casing may or may not have an insulating coating on the bottom surface of the first battery and the surface corresponding to the bottom surface of the second battery. A first limiting strip may or may not be provided between the bottom surface of each battery and the housing.

3. The battery pack according to claim 2, characterized in that, In relation (1), the R bb2 Calculate according to the following relation (2): In the relationship (2), ρ2 is the volume resistivity of the structural adhesive, r2 is the radius of the rounded corner of the side of the battery, L1 is the thickness of the first insulating film, W1 is the thickness of the first buffer pad, W2 is the thickness of the second buffer pad, and H3 is the height of the hollow area.

4. The battery pack according to claim 3, characterized in that, When the insulating coating is not provided, R in equation (1) bc Calculate according to the following relationship (3): When the insulating coating is provided, R in equation (1) bc Calculate according to the following relation (4): In the above equations (3) and (4), ρ1 is the volume resistivity of the first limiting strip, ρ2 is the volume resistivity of the structural adhesive, H1 is the thickness of the structural adhesive between the bottom surface of a single battery and the housing, S is the bottom surface area of ​​a single battery, n1 is the number of first limiting strips corresponding to the bottom surface of a single battery, S1 is the contact area between a single first limiting strip and the bottom surface of a single battery, ρ3 is the volume resistivity of the insulating coating, and L2 is the thickness of the insulating coating.

5. The battery pack according to any one of claims 2-4, characterized in that, The first buffer pad connects the first battery and the second battery in the battery cell into one unit by means of adhesive bonding. And / or, the second buffer pad connects two adjacent rows of battery cells into one unit by means of adhesive bonding; And / or, a support structure is provided on the outside of the battery cell to keep the first buffer pad in a compressed state.

6. The battery pack according to any one of claims 1-4, characterized in that, The rounded corner area at the bottom of the second battery is located within the hollowed-out area.

7. The battery pack according to any one of claims 1-4, characterized in that, The second battery of each battery cell includes a side facing the adjacent row of battery cells, and the lower edge of the casing of the second battery corresponding to the hollow area of ​​the side is covered by a second insulating film.

8. The battery pack according to claim 7, characterized in that, Between two adjacent rows of battery cells, each battery cell includes a side facing the adjacent row of battery cells, the lower edge of which is rounded and covered by a second insulating film. In the outer battery cell, the lower edge rounded corner of the side opposite to the side of the battery with the second insulating film is also covered by the second insulating film.

9. The battery pack according to any one of claims 1-4, characterized in that, Inside the housing, a second limiting strip is provided on the outside of the battery cell located on the outer side to limit the overflow height of the structural adhesive and to allow the structural adhesive to cover the hollow area.

10. The battery pack according to claim 4, characterized in that, The ρ1≥1×10 13 Ω·cm, where ρ2≥7.5×10 9 Ω·cm, where ρ3≥1×10 13 Ω·cm; And / or, the material of the structural adhesive is selected from one or more of polyurethane and epoxy resin; And / or, the thickness W1 of the first buffer pad is 0.5-1.5 mm; And / or, the thickness W2 of the second buffer pad is 0.5-5mm; And / or, the thickness L1 of the first insulating film is 0.015-0.2 mm; And / or, the thickness H1 of the structural adhesive between the bottom surface of a single battery and the housing is 0.5-2.5 mm; And / or, the thickness L2 of the insulating coating is 0.1-0.3 mm; And / or, the height H2 of the second limiting bar satisfies: H1+r1≤H2≤H1+r1+3mm, where r1 is the radius of the rounded corner at the bottom of the battery; And / or, the height H3 of the hollowed-out area satisfies: r1 < H3 ≤ H2, where r1 is the radius of the bottom corner of the battery; And / or, 0 < r2 ≤ 3.5 mm.

Images